Publications by authors named "Alexander M Aiken"

26 Publications

  • Page 1 of 1

Association between SARS-CoV-2 exposure and antibody status among healthcare workers in two London hospitals: a cross-sectional study.

Infect Prev Pract 2021 Sep 22;3(3):100157. Epub 2021 Jun 22.

London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.

Background: Patient-facing (frontline) health-care workers (HCWs) are at high risk of repeated exposure to SARS-CoV-2.

Aim: We sought to determine the association between levels of frontline exposure and likelihood of SARS-CoV-2 seropositivity amongst HCW.

Methods: A cross-sectional study was undertaken using purposefully collected data from HCWs at two hospitals in London, United Kingdom (UK) over eight weeks in May-June 2020. Information on sociodemographic, clinical and occupational characteristics was collected using an anonymised questionnaire. Serology was performed using split SARS-CoV-2 IgM/IgG lateral flow immunoassays. Exposure risk was categorised into five pre-defined ordered grades. Multivariable logistic regression was used to examine the association between being frontline and SARS-CoV-2 seropositivity after controlling for other risks of infection.

Findings: 615 HCWs participated in the study. 250/615 (40.7%) were SARS-CoV-2 IgM and/or IgG positive. After controlling for other exposures, there was non-significant evidence of a modest association between being a frontline HCW (any level) and SARS-CoV-2 seropositivity compared to non-frontline status (OR 1.39, 95% CI 0.84-2.30, =0.200). There was 15% increase in the odds of SARS-CoV-2 seropositivity for each step along the frontline exposure gradient (OR 1.15, 95% CI 1.00-1.32, =0.043).

Conclusion: We found a high SARS-CoV-2 IgM/IgG seropositivity with modest evidence for a dose-response association between increasing levels of frontline exposure risk and seropositivity. Even in well-resourced hospital settings, appropriate use of personal protective equipment, in addition to other transmission-based precautions for inpatient care of SARS-CoV-2 patients could reduce the risk of hospital-acquired SARS-CoV-2 infection among frontline HCW.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.infpip.2021.100157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8217738PMC
September 2021

Mortality attributable to third-generation cephalosporin resistance in Gram-negative bloodstream infections in African hospitals: a multi-site retrospective study.

JAC Antimicrob Resist 2021 Mar 19;3(1):dlaa130. Epub 2021 Jan 19.

Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.

Background: Bloodstream infections (BSI) caused by Enterobacteriaceae show increasing frequency of resistance to third-generation cephalosporin (3GC) antibiotics on the African continent but the mortality impact has not been quantified.

Methods: We used historic data from six African hospitals to assess the impact of 3GC resistance on clinical outcomes in and BSI. We matched each bacteraemic patient to two uninfected patients. We compared outcomes between 3GC-susceptible and 3GC-resistant BSI and their respective uninfected controls using Cox regression models.

Results: For 1431 BSI patients, we matched 1152 (81%) 3GC-susceptible and 279 (19%) 3GC-resistant cases to 2263 and 546 uninfected inpatient controls. For 1368 BSI patients, we matched 502 (37%) 3GC-susceptible and 866 (63%) 3GC-resistant cases to 982 and 1656 uninfected inpatient controls. We found that 3GC-resistant had similar hazard ratios (HRs) for in-hospital mortality over their matched controls as compared to susceptible infections over their controls (ratio of HRs 1.03, 95% CI 0.73-1.46). Similarly, 3GC-resistance in BSI was not associated with mortality (ratio of HR 1.10, 95% CI 0.80-1.52). Estimates of mortality impact varied by site without a consistent pattern.

Conclusions: In a retrospective analysis, including the use of matched uninfected patients, there did not appear to be an impact of 3GC-resistance on mortality in or BSI in African hospitals, as compared with susceptible BSI with equivalent species. Better information on the actual use of antibiotics in treating infections in African hospitals would improve these impact estimates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jacamr/dlaa130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8210247PMC
March 2021

Postnatal infection surveillance by telephone in Dar es Salaam, Tanzania: An observational cohort study.

PLoS One 2021 1;16(7):e0254131. Epub 2021 Jul 1.

Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.

Introduction: Maternal and newborn infections are important causes of mortality but morbidity data from low- and middle-income countries is limited. We used telephone surveillance to estimate infection incidence and risk factors in women and newborns following hospital childbirth in Dar es Salaam.

Methods: We recruited postnatal women from two tertiary hospitals and conducted telephone interviews 7 and 28 days after delivery. Maternal infection (endometritis, caesarean or perineal wound, or urinary tract infection) and newborn infection (umbilical cord or possible severe bacterial infection) were identified using hospital case-notes at the time of birth and self-reported symptoms. Adjusted Cox regression models were used to assess the association between potential risk-factors and infection.

Results: We recruited 879 women and interviewed 791 (90%). From day 0-7, 6.7% (49/791) women and 6.2% (51/762) newborns developed infection. Using full follow-up data, the infection rate was higher in women with caesarean childbirth versus women with a vaginal delivery (aHR 1.93, 95%CI 1.11-3.36). Only 24% of women received pre-operative antibiotic prophylaxis before caesarean section. Infection was higher in newborns resuscitated at birth versus newborns who were not resuscitated (aHR 4.45, 95%CI 2.10-9.44). At interview, 66% (37/56) of women and 88% (72/82) of newborns with possible infection had sought health-facility care.

Conclusions: Telephone surveillance identified a substantial risk of postnatal infection, including cases likely to have been missed by hospital-based data-collection alone. Risk of maternal endometritis and newborn possible severe bacterial infection were consistent with other studies. Caesarean section was the most important risk-factor for maternal infection. Improved implementation of pre-operative antibiotic prophylaxis is urgently required to mitigate this risk.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0254131PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8248639PMC
July 2021

Cleaning Neonatal Units in Low-resource Settings: A Hot-topic in Waiting?

Pediatr Infect Dis J 2021 May;40(5S):S1-S4

From the Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom.

Globally, about 3-quarters of births now occur in healthcare facilities, with the proportion being 50% for sub-Saharan Africa, where healthcare-associated infections among newborns are typically 3-20 times higher than in facilities in high-income countries. As this upward trend in institutional deliveries continues, the demand for specialized neonatal care also rises, with dedicated units often only available in tertiary referral hospitals in the case of low- and middle-income countries. Preventing nosocomial infections among vulnerable newborns requires effective and feasible control strategies and interventions. The role of cleaning and cleaners in reducing risks and maintaining a clean safe environment has until very recently been neglected at policy, program, practice, and research levels. There is now an opportunity to reposition cleaning within global and national initiatives related to Water, Sanitation and Hygiene, Infection Prevention and Control, and Antimicrobial Resistance. The evidence base should also be strengthened on cost-effective bundles of cleaning interventions, particularly in the context of low-resource settings. Here increasing overcrowding and shortages of staff and supplies present major threats to neonatal survival and well-being and heighten the case for optimizing the use of low-cost, back-to-basics interventions like cleaning.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/INF.0000000000002927DOI Listing
May 2021

The association between antimicrobial resistance and HIV infection: a systematic review and meta-analysis.

Clin Microbiol Infect 2021 Jun 1;27(6):846-853. Epub 2021 Apr 1.

Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Biomedical Research and Training Institute, Harare, Zimbabwe; Division of Infectious and Tropical Medicine, Medical Centre of the University of Munich, Munich, Germany.

Objectives: People living with HIV (PLWH) are at increased risk of infections with resistant organisms due to more frequent healthcare utilization. Our objective was to investigate the association between HIV and antimicrobial resistance (AMR).

Methods: We searched MEDLINE, EMBASE, Web of Science, LILACS and African Journals Online. Studies were eligible if they reported on AMR for colonization or infection with bacterial pathogens (excluding mycobacteria and bacteria causing sexually transmitted infections) and were stratified by HIV status, species and antimicrobials tested. Pooled odds ratios were used to evaluate the association between HIV and resistance.

Results: In total, 92 studies published between 1995 and 2020 were identified. The studies included the following organisms: Staphylococcusaureus (n = 47), Streptococcus pneumoniae (n = 28), Escherichia coli (n = 6) and other Gram-negative bacteria. PLWH had a 2.12 (95%CI 1.36-3.30) higher odds for colonization and 1.90 (95%CI 1.45-2.48) higher odds for infection with methicillin-resistant S. aureus, a 2.28 (95%CI 1.75-2.97) higher odds of infection with S. pneumoniae with decreased penicillin susceptibility, and a 1.59 (95%CI 0.83-3.05) higher odds of resistance to third-generation cephalosporins in E. coli and Klebsiella pneumoniae.

Conclusion: This review shows an increased risk of AMR in PLWH across a range of bacterial pathogens and multiple drug classes. The lack of laboratory capacity for identifying AMR, and limited access to alternative treatment options in countries with the highest burden of HIV, highlight the need for more research on AMR in PLWH. Overall, the quality of studies was moderate or low, which may impact the findings of this review.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cmi.2021.03.026DOI Listing
June 2021

The Clean pilot study: evaluation of an environmental hygiene intervention bundle in three Tanzanian hospitals.

Antimicrob Resist Infect Control 2021 01 7;10(1). Epub 2021 Jan 7.

Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.

Background: Healthcare associated infections (HAI) are estimated to affect up to 15% of hospital inpatients in low-income countries (LICs). A critical but often neglected aspect of HAI prevention is basic environmental hygiene, particularly surface cleaning and linen management. TEACH CLEAN is an educational intervention aimed at improving environmental hygiene. We evaluated the effectiveness of this intervention in a pilot study in three high-volume maternity and newborn units in Dar es Salaam, Tanzania.

Methods: This study design prospectively evaluated the intervention as a whole, and offered a before-and-after comparison of the impact of the main training. We measured changes in microbiological cleanliness [Aerobic Colony Counts (ACC) and presence of Staphylococcus aureus] using dipslides, and physical cleaning action using gel dots. These were analysed with descriptive statistics and logistic regression models. We used qualitative (focus group discussions, in-depth interviews, and semi-structured observation) and quantitative (observation checklist) tools to measure why and how the intervention worked. We describe these findings across the themes of adaptation, fidelity, dose, reach and context.

Results: Microbiological cleanliness improved during the study period (ACC pre-training: 19%; post-training: 41%). The odds of cleanliness increased on average by 1.33 weekly during the pre-training period (CI = 1.11-1.60), and by 1.08 (CI = 1.03-1.13) during the post-training period. Cleaning action improved only in the pre-training period. Detection of S. aureus on hospital surfaces did not change substantially. The intervention was well received and considered feasible in this context. The major pitfalls in the implementation were the limited number of training sessions at the hospital level and the lack of supportive supervision. A systems barrier to implementation was lack of regular cleaning supplies.

Conclusions: The evaluation suggests that improvements in microbiological cleanliness are possible using this intervention and can be sustained. Improved microbiological cleanliness is a key step on the pathway to infection prevention in hospitals. Future research should assess whether this bundle is cost-effective in reducing bacterial and viral transmission and infection using a rigorous study design.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13756-020-00866-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789081PMC
January 2021

The effect of behavioural interventions targeting hand hygiene practices among nurses in high-income hospital settings: a systematic review.

Public Health Rev 2020 Dec 7;41(1):29. Epub 2020 Dec 7.

Department of Infectious Disease, London School of Hygiene and Tropical Medicine, London, UK.

Background: Hand hygiene is a critical behaviour for infection control but efforts to raise compliance among clinical professionals have been met with mixed success. The aim of this systematic review was to identify the effectiveness of the behaviour change techniques utilised in recent hand hygiene interventions that seek to improve hand hygiene compliance among nurses in hospitals in high-income countries. Nurses are at the frontline of healthcare delivery, and so improving their HH behaviour and thus increasing HHC rates will have a relatively large impact on reducing transmission and preventing healthcare acquired infections.

Methods: High-quality studies among nurses in high-income countries were surveyed from the scientific literature, following PRISMA guidelines, to identify which kinds of behaviour change mechanisms have been used to effectively increase hand hygiene compliance. Only seven studies met all inclusion criteria. A formal meta-analysis was not conducted due to the heterogeneity of the included studies. Instead, the review analysed studies in line with the Intervention Component Analysis approach to identify which differences in intervention characteristics appear to be important. Analysis proceeded in two steps: first, the Effective Practice and Organization of Care Data Extraction Checklist was used to identify the study design and to describe the intervention, target population, setting, results, outcome measures, and analytic approach. The second step involved inferring the behavioural change techniques used in the complex study interventions. Following coding, logic models were then inferred for each study to identify the Theory of Change behind each intervention. These Theories of Change were then examined for suggestions as to which BCTs were likely to have been responsible for any effectiveness observed.

Results: Goals and planning (to achieve specific ends), comparison of behaviour (to peers or some ideal) and feedback and monitoring (observing and providing feedback about behaviour or outcomes) were the most frequently used behaviour change technique groupings used across studies and within interventions.

Conclusion: The complexity of the interventions used and lack of sufficient studies makes assignment of responsibility for behaviour change to specific behaviour change techniques difficult. Delivery channels and activities identified in the study Theories of Change were also highly individualized and so difficult to compare. However, we identified a temporal shift in types of techniques used in these recent studies on HH interventions, as compared with studies from prior to the review period. These newer interventions did not focus on providing access to alcohol-based hand rub or trying to solely encourage administrative support. Instead, they had nurses create goals and plan how to best facilitate HH, compared both individuals' and the group's behaviour to others, and focused on providing feedback.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40985-020-00141-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7720577PMC
December 2020

Feasibility of informing syndrome-level empiric antibiotic recommendations using publicly available antibiotic resistance datasets.

Wellcome Open Res 2019 24;4:140. Epub 2020 Jun 24.

Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.

Antibiotics are often prescribed empirically to treat infection syndromes before causative bacteria and their susceptibility to antibiotics are identified. Guidelines on empiric antibiotic prescribing are key to effective treatment of infection syndromes, and need to be informed by likely bacterial aetiology and antibiotic resistance patterns. We aimed to create a clinically-relevant composite index of antibiotic resistance for common infection syndromes to inform recommendations at the national level. To create our index, we used open-access antimicrobial resistance (AMR) surveillance datasets, including the ECDC Surveillance Atlas, CDDEP ResistanceMap, WHO GLASS and the newly-available Pfizer ATLAS dataset. We integrated these with data on aetiology of common infection syndromes, existing empiric prescribing guidelines, and pricing and availability of antibiotics.  The ATLAS dataset covered many more bacterial species (287) and antibiotics (52) than other datasets (ranges = 8-11 and 16-32 respectively), but had a similar number of samples per country per year. Using these data, we were able to make empiric prescribing recommendations for bloodstream infection, pneumonia and cellulitis/skin abscess in up to 44 countries. There was insufficient data to make national-level recommendations for the other six syndromes investigated. Results are presented in an interactive web app, where users can visualise underlying resistance proportions to first-line empiric antibiotics for infection syndromes and countries of interest. We found that whilst the creation of a composite resistance index for empiric antibiotic therapy was technically feasible, the ATLAS dataset in its current form can only inform on a limited number of infection syndromes. Other open-access AMR surveillance datasets are largely limited to bloodstream infection specimens and cannot directly inform treatment of other syndromes. With improving availability of international AMR data and better understanding of infection aetiology, this approach may prove useful for informing empiric prescribing decisions in settings with limited local AMR surveillance data.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12688/wellcomeopenres.15477.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327722PMC
June 2020

Nosocomial Infections During Extracorporeal Membrane Oxygenation in Neonatal, Pediatric, and Adult Patients: A Comprehensive Narrative Review.

Pediatr Crit Care Med 2020 03;21(3):283-290

Department of Infection, Imperial College Healthcare NHS Trust, London, United Kingdom.

Objectives: Extracorporeal membrane oxygenation is increasingly used in critically ill patients with refractory cardiopulmonary failure. Nosocomial infection acquired during extracorporeal membrane oxygenation represents one of the most frequent complications but the available evidence on the risk of infection and its association with outcomes has not been comprehensively analyzed. We performed a narrative review examining the epidemiology of nosocomial infection during extracorporeal membrane oxygenation, association with clinical outcomes, and preventive strategies.

Data Sources: We searched PubMed, Web of Science, EMBASE, and the Cochrane Library between 1972 and June 2018.

Study Selection: We included any article which detailed nosocomial infection during extracorporeal membrane oxygenation. Articles were excluded if they were not written in English, detailed extracorporeal membrane oxygenation use for infections acquired prior to extracorporeal membrane oxygenation, or used other forms of extracorporeal support such as ventricular assist devices.

Data Extraction: Two reviewers independently assessed eligibility and extracted data. We screened 984 abstracts and included 59 articles in the final review.

Data Synthesis: The reported risk of nosocomial infection among patients receiving extracorporeal membrane oxygenation ranged from 3.5% to 64% per extracorporeal membrane oxygenation run, while the incidence of infection ranged from 10.1 to 116.2/1,000 extracorporeal membrane oxygenation days. Nosocomial infections during extracorporeal membrane oxygenation were consistently associated with longer duration of extracorporeal membrane oxygenation and, in several large multicenter studies, with increased mortality. Risk factors for nosocomial infection included duration of extracorporeal membrane oxygenation, mechanical and hemorrhagic complications on extracorporeal membrane oxygenation, and use of venoarterial and central extracorporeal membrane oxygenation. Biomarkers had low specificity for infection in this population. Few studies examined strategies on how to prevent nosocomial infection on extracorporeal membrane oxygenation.

Conclusions: Nosocomial infections in extracorporeal membrane oxygenation patients are common and associated with worse outcomes. There is substantial variation in the rates of reported infection, and thus, it is possible that some may be preventable. The evidence for current diagnostic, preventive, and therapeutic strategies for infection during extracorporeal membrane oxygenation is limited and requires further investigation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/PCC.0000000000002190DOI Listing
March 2020

Implementation of a surgical unit-based safety programme in African hospitals: a multicentre qualitative study.

Antimicrob Resist Infect Control 2019 30;8:91. Epub 2019 May 30.

Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Rämistrasse 100, HAL 14, 8091 Zurich, Switzerland.

Background: A Surgical Unit-based Safety Programme (SUSP) has been shown to improve perioperative prevention practices and to reduce surgical site infections (SSI). It is critical to understand the factors influencing the successful implementation of the SUSP approach in low- and middle-income settings. We undertook a qualitative study to assess viability, and understand facilitators and barriers to implementing the SUSP approach in 5 African hospitals.

Methods: Qualitative study based on interviews with individuals from all hospitals participating in a WHO-coordinated before-after SUSP study. The SUSP intervention consisted of a multimodal strategy including multiple SSI prevention measures combined with an adaptive approach aimed at improving teamwork and safety culture.

Results: Thirteen interviews (5 head surgeons, 3 surgeons, 5 nurses) were conducted with staff from five hospital sites. Identified facilitators included (intrinsic motivation of local SUSP teams, boundary spanners, multidisciplinary engagement, active leadership support), (hospital networking and positive deviance, benchmarking), (enabling infrastructures, momentum from previous projects), and of infection rates and process indicators. Barriers (organisational 'constipators', workload, mistrust, turnover) and local solutions to these were also identified.

Conclusions: Participating hospitals benefitted from the SUSP programme structures (e.g. surveillance, hospital networks, formation of multidisciplinary teams) and adaptive tools (e.g. learning from defects, executive rounds guide) to change perceptions around patient safety and improve behaviours to prevent SSI. The combination of technical and adaptive elements represents a promising approach to facilitate the introduction of evidence-based best practices and to improve safety culture through local team engagement in resource-limited settings.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13756-019-0541-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6543622PMC
May 2020

A multimodal infection control and patient safety intervention to reduce surgical site infections in Africa: a multicentre, before-after, cohort study.

Lancet Infect Dis 2018 05 5;18(5):507-515. Epub 2018 Mar 5.

Johns Hopkins Armstrong Institute for Patient Safety and Quality, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Background: Surgical site infections (SSIs) are the most frequent health-care-associated infections in developing countries. Specific prevention measures are highly effective, but are often poorly implemented. We aimed to establish the effect of a multimodal intervention on SSIs in Africa.

Methods: We did a before-after cohort study, between July 1, 2013, and Dec 31, 2015, at five African hospitals. The multimodal intervention consisted of the implementation or strengthening of multiple SSI prevention measures, combined with an adaptive approach aimed at the improvement of teamwork and the safety climate. The primary outcome was the first occurrence of SSI, and the secondary outcome was death within 30 days post surgery. Data on adherence to SSI prevention measures were prospectively collected. The intervention effect on SSI risk and death within 30 days post surgery was assessed in a mixed-effects logistic regression model, after adjustment for key confounders.

Findings: Four hospitals completed the baseline and follow-up; three provided suitable (ie, sufficient number and quality) data for the sustainability period. 4322 operations were followed up (1604 at baseline, 1827 at follow-up, and 891 in the sustainability period). SSI cumulative incidence significantly decreased post intervention, from 8·0% (95% CI 6·8-9·5; n=129) to 3·8% (3·0-4·8; n=70; p<0·0001), and this decrease persisted in the sustainability period (3·9%, 2·8-5·4; n=35). A substantial improvement in compliance with prevention measures was consistently observed in the follow-up and sustainability periods. The likelihood of SSI during follow-up was significantly lower than pre-intervention (odds ratio [OR] 0·40, 95% CI 0·29-0·54; p<0·0001), but the likelihood of death was not significantly reduced (0·72, 0·42-1·24; p=0·2360).

Interpretation: Implementation of our intervention is feasible in African hospitals. Improvement was observed across all perioperative prevention practices. A significant effect on the overall SSI risk was observed, but with some heterogeneity between sites. Further large-scale experimental studies are needed to confirm these results and to improve the sustainability and long-term effect of such complex programmes.

Funding: US Agency for Healthcare Research and Quality, WHO.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S1473-3099(18)30107-5DOI Listing
May 2018

Bias and inference from misspecified mixed-effect models in stepped wedge trial analysis.

Stat Med 2017 Oct 28;36(23):3670-3682. Epub 2017 May 28.

Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, U.K.

Many stepped wedge trials (SWTs) are analysed by using a mixed-effect model with a random intercept and fixed effects for the intervention and time periods (referred to here as the standard model). However, it is not known whether this model is robust to misspecification. We simulated SWTs with three groups of clusters and two time periods; one group received the intervention during the first period and two groups in the second period. We simulated period and intervention effects that were either common-to-all or varied-between clusters. Data were analysed with the standard model or with additional random effects for period effect or intervention effect. In a second simulation study, we explored the weight given to within-cluster comparisons by simulating a larger intervention effect in the group of the trial that experienced both the control and intervention conditions and applying the three analysis models described previously. Across 500 simulations, we computed bias and confidence interval coverage of the estimated intervention effect. We found up to 50% bias in intervention effect estimates when period or intervention effects varied between clusters and were treated as fixed effects in the analysis. All misspecified models showed undercoverage of 95% confidence intervals, particularly the standard model. A large weight was given to within-cluster comparisons in the standard model. In the SWTs simulated here, mixed-effect models were highly sensitive to departures from the model assumptions, which can be explained by the high dependence on within-cluster comparisons. Trialists should consider including a random effect for time period in their SWT analysis model. © 2017 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/sim.7348DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5600088PMC
October 2017

Reliability and validity of using telephone calls for post-discharge surveillance of surgical site infection following caesarean section at a tertiary hospital in Tanzania.

Antimicrob Resist Infect Control 2017 8;6:43. Epub 2017 May 8.

'Lazzaro Spallanzani' National Institute for Infectious Diseases-IRCCS, Rome, Italy.

Background: Surgical site infection (SSI) is a common post-operative complication causing significant morbidity and mortality. Many SSI occur after discharge from hospital. Post-discharge SSI surveillance in low and middle income countries needs to be improved.

Methodology: We conducted an observational cohort study in Dodoma, Tanzania to examine the sensitivity and specificity of telephone calls to detect SSI after discharge from hospital in comparison to a gold standard of clinician review. Women undergoing caesarean section were enrolled and followed up for 30 days. Women providing a telephone number were interviewed using a structured questionnaire at approximately days 5, 12 and 28 post-surgery. Women were then invited for out-patient review by a clinician blinded to the findings of telephone interview.

Results: A total of 374 women were enrolled and an overall SSI rate of 12% ( = 45) was observed. Three hundred and sixteen (84%) women provided a telephone number, of which 202 had at least one telephone interview followed by a clinical review within 48 h, generating a total of 484 paired observations. From the clinical reviews, 25 SSI were diagnosed, of which telephone interview had correctly identified 18 infections; telephone calls did not incorrectly identify SSI in any patients. The overall sensitivity and specificity of telephone interviews as compared to clinician evaluation was 72 and 100%, respectively.

Conclusion: The use of telephone interview as a diagnostic tool for post-discharge surveillance of SSI had moderate sensitivity and high specificity in Tanzania. Telephone-based detection may be a useful method for SSI surveillance in low-income settings with high penetration of mobile telephones.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13756-017-0205-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5422869PMC
May 2017

Commentary: The tide continues to move on mass deworming-where are we now?

Int J Epidemiol 2016 12;45(6):2161-2163

International Initiative for Impact Evaluation (3ie), Washington, DC, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ije/dyw345DOI Listing
December 2016

Carriage of antibiotic-resistant in hospitalised children in tertiary hospitals in Harare, Zimbabwe.

Antimicrob Resist Infect Control 2017 11;6:10. Epub 2017 Jan 11.

Biomedical Research and Training Institute, Harare, Zimbabwe ; London School of Hygiene and Tropical Medicine, London, UK.

Background: Extended-spectrum β-lactamase-producing and gentamicin resistant are increasingly recognised as a major cause of infection in low-income countries. We assessed the prevalence of gastrointestinal carriage of these bacteria in hospitalised children in Harare, Zimbabwe.

Methods: We conducted a cohort study in paediatric inpatients at two tertiary-referral hospitals between May and July 2015. Rectal swabs and faecal samples were collected within 24 h of admission and further follow-up samples were collected on alternate days during hospitalization. Disc-based, selective and enrichment methods were used to detect carriage of these two forms of resistance. Standard methods were used to confirm resistance status and determine the susceptibility of resistant isolates to other commonly-used antibiotics.

Results: One hundred and sixty four paediatric inpatient admissions (median age = 1.0 year, IQR = 0.2-2.2years) were enrolled, and an average of 1.9 faecal samples per patient were collected. On admission, 68/164 (41%) patients had both ESBL and gentamicin-resistant detected, 18 (11%) had ESBL only, 17 (10%) had gentamicin resistance only and 61 (37%) had negative screening for both forms of resistance. During hospitalisation, 32/164 (20%) patients were found to have a type of resistant organism which was not present in their admission sample. We found that faecal samples and use of a selective enrichment broth enhanced the detection of resistant organisms. Amongst resistant bacteria isolated, there were high levels of resistance to ciprofloxacin and chloramphenicol, but not ertapenem.

Conclusions: More than half of children had enteric carriage of a clinically-relevant form of antibiotic resistance on admission to public-sector hospitals in urban Zimbabwe. Additionally, a fifth of children acquired a further form of resistance during hospitalisation. Urgent action is needed to tackle the spread of antibiotic resistant enteric bacteria in African hospitals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13756-016-0155-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5225579PMC
January 2017

Effect of handrubbing using locally-manufactured alcohol-based handrubs in paediatric wards in Harare, Zimbabwe.

Antimicrob Resist Infect Control 2017 11;6. Epub 2017 Jan 11.

London School of Hygiene and Tropical Medicine, London, UK ; Biomedical Research and Training Institute, Harare, Zimbabwe.

We assessed bacterial contamination of hands of adults present in paediatric wards in two tertiary-care hospitals in Harare, Zimbabwe and the microbiologic efficacy of locally-manufactured alcohol-based hand rub (ABHR). During unannounced visits, samples were collected using hand-print and hand-rinse methods. Samples were collected from 152 individuals (16 nurses, 10 doctors, 28 students, 86 parents/guardians, 12 others). Contamination of hands with Gram-negative bacteria was found in 91% of adults tested with a mean of 14.6 CFU (hand-rinse method; IQR 3-65), representing a high risk for transmission of pathogens potentially leading to nosocomial infections. A single application of ABHR under controlled conditions achieved an average of 82% (or 0.72 log) reduction in detectable counts. Amongst 49 isolates from hands, 53% were resistant to gentamicin and 63% were resistant to cefpodoxime. Use of ABHR represents an attractive intervention for reducing nosocomial infections in this setting.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13756-016-0166-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5225549PMC
January 2017

Authors' Response to: Deworming externalities and school impacts in Kenya.

Int J Epidemiol 2015 Oct 22;44(5):1596-9. Epub 2015 Jul 22.

Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ije/dyv130DOI Listing
October 2015

Re-analysis of health and educational impacts of a school-based deworming programme in western Kenya: a statistical replication of a cluster quasi-randomized stepped-wedge trial.

Int J Epidemiol 2015 Oct 22;44(5):1581-92. Epub 2015 Jul 22.

Department of Social and Environmental Health Research, and.

Introduction: Helminth (worm) infections cause morbidity among poor communities worldwide. An influential study conducted in Kenya in 1998-99 reported that a school-based drug-and-educational intervention had benefits for worm infections and school attendance.

Methods: In this statistical replication, we re-analysed data from this cluster quasi-randomized stepped-wedge trial, specifying two co-primary outcomes: school attendance and examination performance. We estimated intention-to-treat effects using year-stratified cluster-summary analysis and observation-level random-effects regression, and combined both years with a random-effects model accounting for year. The participants were not blinded to allocation status, and other interventions were concurrently conducted in a sub-set of schools. A protocol guiding outcome data collection was not available.

Results: Quasi-randomization resulted in three similar groups of 25 schools. There was a substantial amount of missing data. In year-stratified cluster-summary analysis, there was no clear evidence for improvement in either school attendance or examination performance. In year-stratified regression models, there was some evidence of improvement in school attendance [adjusted odds ratios (aOR): year 1: 1.48, 95% confidence interval (CI) 0.88-2.52, P = 0.147; year 2: 1.23, 95% CI 1.01-1.51, P = 0.044], but not examination performance (adjusted differences: year 1: -0.135, 95% CI -0.323-0.054, P = 0.161; year 2: -0.017, 95% CI -0.201-0.166, P = 0.854). When both years were combined, there was strong evidence of an effect on attendance (aOR 1.82, 95% CI 1.74-1.91, P < 0.001), but not examination performance (adjusted difference -0.121, 95% CI -0.293-0.052, P = 0.169).

Conclusions: The evidence supporting an improvement in school attendance differed by analysis method. This, and various other important limitations of the data, caution against over-interpretation of the results. We find that the study provides some evidence, but with high risk of bias, that a school-based drug-treatment and health-education intervention improved school attendance and no evidence of effect on examination performance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ije/dyv128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681108PMC
October 2015

Re-analysis of health and educational impacts of a school-based deworming programme in western Kenya: a pure replication.

Int J Epidemiol 2015 Oct 22;44(5):1572-80. Epub 2015 Jul 22.

Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK.

Background: Helminth (worm) infections cause morbidity among poor communities worldwide. An influential study conducted in Kenya in 1998-99 reported that a school-based drug-and-educational intervention had benefits regarding worm infections and school attendance. Effects were seen among children treated with deworming drugs, untreated children in intervention schools and children in nearby non-intervention schools. Combining these effects, the intervention was reported to increase school attendance by 7.5% in treated children. Effects on other outcomes (worm infections, anaemia, nutritional status and examination performance) were also investigated.

Methods: In this pure replication, we used data provided by the original authors to re-analyse the study according to their methods. We compared these results against those presented in the original paper.

Results: Although most results were reproduced as originally reported, we identified discrepancies of several types between the original findings and re-analysis. For worm infections, re-analysis showed reductions similar to those originally reported. For anaemia prevalence, in contrast to the original findings, re-analysis found no evidence of benefit. For nutritional status, both original findings and re-analysis described modest evidence for a small improvement. For school attendance, re-analysis showed benefits similar to those originally found in intervention schools for both children who did and those who did not receive deworming drugs. However, after correction of coding errors, there was little evidence of an indirect effect on school attendance among children in schools close to intervention schools. Combining these effects gave a total increase in attendance of 3.9% among treated children, which was no longer statistically significant. As in the original results, re-analysis found no effect of the intervention on examination performance.

Conclusions: Re-applying analytical approaches originally used, but correcting various errors, we found little evidence for some previously-reported indirect effects of a deworming intervention. Effects on worm infections, nutritional status, examination performance and school attendance on children in intervention schools were largely unchanged.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ije/dyv127DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681107PMC
October 2015

Carriage of Staphylococcus aureus in Thika Level 5 Hospital, Kenya: a cross-sectional study.

Antimicrob Resist Infect Control 2014 15;3:22. Epub 2014 Jul 15.

Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen but little is known about its circulation in hospitals in developing countries. We aimed to describe carriage of S.aureus amongst inpatients in a mid-sized Kenyan government hospital.

Methods: We determined the frequency of S.aureus and MRSA carriage amongst inpatients in Thika Hospital, Kenya by means of repeated cross-sectional ward surveys. For all S.aureus isolates, we performed antibiotic susceptibility tests, genomic profiling using a DNA microarray and spa typing and MLST.

Results: In this typical mid-sized Kenyan Government hospital, we performed 950 screens for current carriage of S.aureus amongst inpatients over a four month period. We detected S.aureus carriage (either MSSA or MRSA) in 8.9% (85/950; 95%CI 7.1-10.8) of inpatient screens, but patients with multiple screens were more likely have detection of carriage. MRSA carriage was rare amongst S.aureus strains carried by hospital inpatients - only 7.0% (6/86; 95%CI 1.5-12.5%) of all isolates were MRSA. Most MRSA (5/6) were obtained from burns patients with prolonged admissions, who only represented a small proportion of the inpatient population. All MRSA strains were of the same clone (MLST ST239; spa type t037) with concurrent resistance to multiple antibiotic classes. MSSA isolates were diverse and rarely expressed antibiotic resistance except against benzyl-penicillin and co-trimoxazole.

Conclusions: Although carriage rates for S.aureus and the MRSA prevalence in this Kenyan hospital were both low, burns patient were identified as a high risk group for carriage. The high frequency of genetically indistinguishable isolates suggests that there was local transmission of both MRSA and MSSA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/2047-2994-3-22DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4107749PMC
July 2014

Antibiotic resistance needs global solutions.

Lancet Infect Dis 2014 Jul;14(7):550-1

Department of Medical Microbiology, University of Groningen, University Medical Centre, Groningen, Netherlands.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S1473-3099(14)70709-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6872450PMC
July 2014

Changing use of surgical antibiotic prophylaxis in Thika Hospital, Kenya: a quality improvement intervention with an interrupted time series design.

PLoS One 2013 11;8(11):e78942. Epub 2013 Nov 11.

London School of Hygiene and Tropical Medicine, London, United Kingdom ; Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya.

Introduction: In low-income countries, Surgical Site Infection (SSI) is a common form of hospital-acquired infection. Antibiotic prophylaxis is an effective method of preventing these infections, if given immediately before the start of surgery. Although several studies in Africa have compared pre-operative versus post-operative prophylaxis, there are no studies describing the implementation of policies to improve prescribing of surgical antibiotic prophylaxis in African hospitals.

Methods: We conducted SSI surveillance at a typical Government hospital in Kenya over a 16 month period between August 2010 and December 2011, using standard definitions of SSI and the extent of contamination of surgical wounds. As an intervention, we developed a hospital policy that advised pre-operative antibiotic prophylaxis and discouraged extended post-operative antibiotics use. We measured process, outcome and balancing effects of this intervention in using an interrupted time series design.

Results: From a starting point of near-exclusive post-operative antibiotic use, after policy introduction in February 2011 there was rapid adoption of the use of pre-operative antibiotic prophylaxis (60% of operations at 1 week; 98% at 6 weeks) and a substantial decrease in the use of post-operative antibiotics (40% of operations at 1 week; 10% at 6 weeks) in Clean and Clean-Contaminated surgery. There was no immediate step-change in risk of SSI, but overall, there appeared to be a moderate reduction in the risk of superficial SSI across all levels of wound contamination. There were marked reductions in the costs associated with antibiotic use, the number of intravenous injections performed and nursing time spent administering these.

Conclusion: Implementation of a locally developed policy regarding surgical antibiotic prophylaxis is an achievable quality improvement target for hospitals in low-income countries, and can lead to substantial benefits for individual patients and the institution.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0078942PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3823974PMC
August 2014

Interventional studies for preventing surgical site infections in sub-Saharan Africa - A systematic review.

Int J Surg 2012 14;10(5):242-9. Epub 2012 Apr 14.

London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.

Background: There is a great need for safe surgical services in sub-Saharan Africa, but a major difficulty of performing surgery in this region is the high risk of post-operative surgical site infection (SSI).

Methods: We aimed to systematically review which interventions had been tested in sub-Saharan Africa to reduce the risk of SSI and to synthesize their findings. We searched Medline, Embase and Global Health databases for studies published between 1995 and 2010 without language restrictions and extracted data from full-text articles.

Findings: We identified 24 relevant articles originating from nine countries in sub-Saharan Africa. The methodological quality of these publications was diverse, with inconsistency in definitions used for SSI, period and method of post-operative follow-up and classification of wound contamination. Although it was difficult to synthesise information between studies, there was consistent evidence that use of single-dose pre-operative antibiotic prophylaxis could reduce, sometimes dramatically, the risk of SSI. Several studies indicated that alcohol-based handrubs could provide a low-cost alternative to traditional surgical hand-washing methods. Other studies investigated the use of drains and variants of surgical technique. There were no African studies found relating to several other promising SSI prevention strategies, including use of checklists and SSI surveillance.

Conclusions: There is extremely limited research from sub-Saharan Africa on interventions to curb the occurrence of SSI. Although some of the existing studies are weak, several high-quality studies have been published in recent years. Standard methodological approaches to this subject are needed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijsu.2012.04.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3492758PMC
November 2012

Risk and causes of paediatric hospital-acquired bacteraemia in Kilifi District Hospital, Kenya: a prospective cohort study.

Lancet 2011 Dec 29;378(9808):2021-2027. Epub 2011 Nov 29.

Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya; Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford University, Oxford, UK.

Background: In sub-Saharan Africa, community-acquired bacteraemia is an important cause of illness and death in children. Our aim was to establish the magnitude and causes of hospital-acquired (nosocomial) bacteraemia in African children.

Methods: We reviewed prospectively collected surveillance data of 33,188 admissions to Kilifi District Hospital, Kenya, between April 16, 2002, and Sept 30, 2009. We defined bacteraemia as nosocomial if it occurred 48 h or more after admission. We estimated the per-admission risk, daily rate, effect on mortality, and microbial cause of nosocomial bacteraemia and analysed risk factors by multivariable Cox regression. The effect on morbidity was measured as the increase in hospital stay by comparison with time-matched patients without bacteraemia.

Findings: The overall risk of nosocomial bacteraemia during this period was 5·9/1000 admissions (95% CI 5·2-6·9) but we recorded an underlying rise in risk of 27% per year. The incidence was 1·0/1000 days in hospital (0·87-1·14), which is about 40 times higher than that of community-acquired bacteraemia in the same region. Mortality in patients with nosocomial bacteraemia was 53%, compared with 24% in community-acquired bacteraemia and 6% in patients without bacteraemia. In survivors, nosocomial bacteraemia lengthened hospital stay by 10·1 days (3·0-17·2). Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Acinetobacter spp, group D streptococci, and Pseudomonas aeruginosa accounted for three-quarters of nosocomial infections. Nosocomial bacteraemia was significantly associated with severe malnutrition (hazard ratio 2·52, 95% CI 1·79-3·57) and blood transfusion in children without severe anaemia (4·99; 3·39-7·37).

Interpretation: Our findings show that although nosocomial bacteraemia is rare, it has serious effects on morbidity and mortality, and the microbiological causes are distinct from those of community-acquired bacteraemia. Nosocomial infections are largely unrecognised or undocumented as a health risk in low-income countries, but they are likely to become public health priorities as awareness of their occurrence increases and as other prominent childhood diseases are progressively controlled.

Funding: Wellcome Trust.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S0140-6736(11)61622-XDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3242162PMC
December 2011

Reversion of the ELISPOT test after treatment in Gambian tuberculosis cases.

BMC Infect Dis 2006 Mar 30;6:66. Epub 2006 Mar 30.

Tuberculosis Division, Medical Research Council Laboratories, Banjul, The Gambia.

Background: New tools are required to improve tuberculosis (TB) diagnosis and treatment, including enhanced ability to compare new treatment strategies. The ELISPOT assay uses Mycobacterium tuberculosis-specific antigens to produce a precise quantitative readout of the immune response to pathogen. We hypothesized that TB patients in The Gambia would have reduced ELISPOT counts after successful treatment.

Methods: We recruited Gambian adults with sputum smear and culture positive tuberculosis for ELISPOT assay and HIV test, and followed them up one year later to repeat testing and document treatment outcome. We used ESAT-6, CFP-10 and Purified Protein Derivative (PPD) as stimulatory antigens. We confirmed the reliability of our assay in 23 volunteers through 2 tests one week apart, comparing within and between subject variation.

Results: We performed an ELISPOT test at diagnosis and 12 months later in 89 patients. At recruitment, 70/85 HIV-negative patients (82%) were ESAT-6 or CFP-10 (EC) ELISPOT positive, 77 (90%) were PPD ELISPOT positive. Eighty-two cases (96%) successfully completed treatment: 44 (55%; p < 0.001) were EC ELISPOT negative at 12 months, 17 (21%; p = 0.051) were PPD ELISPOT negative. Sixty (73%) cured cases had a CFP-10 ELISPOT count decrease, 64 (78%) had an ESAT-6 ELISPOT count decrease, 58 (70%) had a PPD ELISPOT count decrease. There was a mean decline of 25, 44 and 47 SFU/2 x 105 cells for CFP-10, ESAT-6 and PPD respectively (p < 0.001 for all). Three of 4 HIV positive patients were cured, all 3 underwent ELISPOT reversion; all 4 not cured subjects (3 HIV-negative, 1 HIV positive) were ESAT-6, CFP-10 and PPD ELISPOT positive at 12 months.

Conclusion: Successful tuberculosis treatment is accompanied by a significant reduction in the M. tuberculosis-specific antigen ELISPOT count. The ELISPOT has potential as a proxy measure of TB treatment outcome. Further investigation into the decay kinetics of T-cells with treatment is warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2334-6-66DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1562425PMC
March 2006
-->