Publications by authors named "Richard Aschbacher"

19 Publications

  • Page 1 of 1

Impact of Prior Antibiotic Use in Primary Care on Resistance to Third Generation Cephalosporins: A Case-Control Study.

Antibiotics (Basel) 2021 Apr 16;10(4). Epub 2021 Apr 16.

Department of Medical Sciences and Public Health, Faculty of Medicine and Surgery, University of Cagliari, 09124 Cagliari, Italy.

Research is lacking on the reversibility of antimicrobial resistance (AMR). Thus, we aimed to determine the influence of previous antibiotic use on the development and decay over time of third generation cephalosporin (3GC)-resistance of . Using the database of hospital laboratories of the Autonomous Province of Bolzano/Bozen (Italy), anonymously linked to the database of outpatient pharmaceutical prescriptions and the hospital discharge record database, this matched case-control study was conducted including as cases all those who have had a positive culture from any site for 3GC resistant (3GCREC) during a 2016 hospital stay. Data were analyzed by conditional logistic regression. 244 cases were matched to 1553 controls by the date of the first isolate. Male sex (OR 1.49, 95% CI 1.10-2.01), older age (OR 1.11, 95% CI 1.02-1.21), the number of different antibiotics taken in the previous five years (OR 1.20, 95% CI 1.08-1.33), at least one antibiotic prescription in the previous year (OR 1.92, 95% CI 1.36-2.71), and the diagnosis of diabetes (OR 1.57, 95% CI 1.08-2.30) were independent risk factors for 3GCREC colonization/infection. Patients who last received an antibiotic prescription two years or three to five years before hospitalization showed non-significant differences with controls (OR 0.97, 95% CI 0.68-1.38 and OR 0.85, 95% CI 0.59-1.24), compared to an OR of 1.92 (95% CI 1.36-2.71) in those receiving antibiotics in the year preceding hospitalization. The effect of previous antibiotic use on 3GC-resistance of is highest after greater cumulative exposure to any antibiotic as well as to 3GCs and in the first 12 months after antibiotics are taken and then decreases progressively.
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http://dx.doi.org/10.3390/antibiotics10040451DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8073604PMC
April 2021

Country Income Is Only One of the Tiles: The Global Journey of Antimicrobial Resistance among Humans, Animals, and Environment.

Antibiotics (Basel) 2020 Aug 1;9(8). Epub 2020 Aug 1.

Infectious Diseases Unit; Bolzano Central Hospital, 39100 Bolzano, Italy.

Antimicrobial resistance (AMR) is one of the most complex global health challenges today: decades of overuse and misuse in human medicine, animal health, agriculture, and dispersion into the environment have produced the dire consequence of infections to become progressively untreatable. Infection control and prevention (IPC) procedures, the reduction of overuse, and the misuse of antimicrobials in human and veterinary medicine are the cornerstones required to prevent the spreading of resistant bacteria. Purified drinking water and strongly improved sanitation even in remote areas would prevent the pollution from inadequate treatment of industrial, residential, and farm waste, as all these situations are expanding the resistome in the environment. The One Health concept addresses the interconnected relationships between human, animal, and environmental health as a whole: several countries and international agencies have now included a One Health Approach within their action plans to address AMR. Improved antimicrobial usage, coupled with regulation and policy, as well as integrated surveillance, infection control and prevention, along with antimicrobial stewardship, sanitation, and animal husbandry should all be integrated parts of any new action plan targeted to tackle AMR on the Earth. Since AMR is found in bacteria from humans, animals, and in the environment, we briefly summarize herein the current concepts of One Health as a global challenge to enable the continued use of antibiotics.
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http://dx.doi.org/10.3390/antibiotics9080473DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7460298PMC
August 2020

Recommendations for the surveillance of multidrug-resistant bacteria in Italian long-term care facilities by the GLISTer working group of the Italian Association of Clinical Microbiologists (AMCLI).

Antimicrob Resist Infect Control 2020 07 13;9(1):106. Epub 2020 Jul 13.

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, Unit of Microbiology and Clinical Microbiology, University of Pavia, Pavia, Italy.

Long-term care facilities (LTCFs) are an important reservoir of multidrug-resistant organisms (MDROs). Colonization of LTCF residents by MDROs is generally higher in Italy compared to other European countries. The present review by the working group for the study of infections in LTCFs (GLISTer) of the Italian Association of Clinical Microbiologists (AMCLI) aims to propose criteria for a laboratory-based surveillance of MDROs in Italian LTCFs.We recommend the adhesion to three levels of laboratory-based MDROs surveillance in LTCFs: i) mandatory MDRO surveillance by cumulative retrospective analysis of antimicrobial susceptibility data, obtained as part of routine care of clinical specimens. ii) strongly recommended surveillance by active rectal swab cultures or molecular screening to determine colonization with carbapenemase-producing Enterobacterales, should a resident be proven infected. iii) voluntary surveillance by prospective MDRO surveys, mainly based on point prevalence colonization studies, allowing to determine the MDROs baseline prevalence in the facility.Laboratory-based surveillance of MDROs in LTCFs is aimed at providing useful epidemiological information to healthcare providers operating in the facility, but it is only effective if the collected data are used for infection prevention and control purposes, targeting the peculiar aspects of LTCFs.
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http://dx.doi.org/10.1186/s13756-020-00771-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356128PMC
July 2020

Colonization of long-term care facility residents in three Italian Provinces by multidrug-resistant bacteria.

Antimicrob Resist Infect Control 2018 6;7:33. Epub 2018 Mar 6.

1Department of Clinical Surgical Diagnostic and Pediatric Sciences, Laboratory of Microbiology and Clinical Microbiology, University of Pavia, Via Brambilla 74, 27100 Pavia, Italy.

Background: Rationale and aims of the study were to compare colonization frequencies with MDR bacteria isolated from LTCF residents in three different Northern Italian regions, to investigate risk factors for colonization and the genotypic characteristics of isolates. The screening included expressing extended-spectrum β-lactamases (ESβLs) and high-level AmpC cephalosporinases, carbapenemase-producing , or , methicillin-resistant (MRSA) and vancomycin-resistant enterococci (VRE).

Methods: Urine samples and rectal, inguinal, oropharyngeal and nasal swabs were plated on selective agar; resistance genes were sought by PCR and sequencing. Demographic and clinical data were collected.

Results: Among the LTCF residents, 75.0% (78/104), 69.4% (84/121) and 66.1% (76/115) were colonized with at least one of the target organisms in LTCFs located in Milan, Piacenza and Bolzano, respectively. ESβL producers (60.5, 66.1 and 53.0%) were highly predominant, mainly belonging to expressing CTX-M group-1 enzymes. Carbapenemase-producing enterobacteria were found in 7.6, 0.0 and 1.6% of residents; carbapemenase-producing and were also detected. Colonization by MRSA (24.0, 5.7 and 14.8%) and VRE (20.2, 0.8 and 0.8%) was highly variable. Several risk factors for colonization by ESβL-producing and MRSA were found and compared among LTCFs in the three Provinces. Colonization differences among the enrolled LTCFs can be partially explained by variation in risk factors, resident populations and staff/resident ratios, applied hygiene measures and especially the local antibiotic resistance epidemiology.

Conclusions: The widespread diffusion of MDR bacteria in LTCFs within three Italian Provinces confirms that LTCFs are an important reservoir of MDR organisms in Italy and suggests that future efforts should focus on MDR screening, improved implementation of infection control strategies and antibiotic stewardship programs targeting the complex aspects of LTCFs.
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http://dx.doi.org/10.1186/s13756-018-0326-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5839059PMC
July 2019

Colonization of residents and staff of an Italian long-term care facility and an adjacent acute care hospital geriatric unit by multidrug-resistant bacteria.

New Microbiol 2017 Oct 10;40(4):258-263. Epub 2017 Oct 10.

Laboratorio Aziendale di Microbiologia e Virologia, Comprensorio Sanitario di Bolzano, Italy.

In 2016, we undertook a point prevalence screening study for Enterobacteriaceae with extended-spectrum β-lactamases (ESBLs), high-level AmpC cephalosporinases and carbapenemases, and also methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin resistant enterococci (VRE) in a long-term care facility (LTCF) and the associated acute care hospital geriatric unit in Bolzano, Northern Italy. Urine samples and rectal, inguinal, oropharyngeal and nasal swabs were plated on selective agars. Demographic data were collected. ESBL and carbapenemase genes were sought by PCR. We found the following colonization percentages with multidrug-resistant (MDR) bacteria in 2016 in LTCF residents: all MDR organisms, 66.1%; ESBL producers, 53.0%; carbapenemase-producers, 1.7%; MRSA, 14.8%; VRE, 0.8%. Colonization by all MDR bacteria was 19.4% for LTCF staff and 26.0% for geriatric unit patients. PCR showed that 80.3% of Escherichia coli isolates from LTCF residents, all E. coli isolates from LTCF staff, 62.5% and 100% of Klebsiella pneumoniae from LTCF residents and geriatric unit patients, respectively, had a blaCTX-M-type gene. All carbapenemase-producing Enterobacteriaceae harboured a blaVIM-type gene. To conclude, the ongoing widespread diffusion of MDR bacteria in the LTCF suggests that efforts should be strengthened on MDR screening, implementation of infection control strategies and antibiotic stewardship programs targeting the unique aspects of LTCFs.
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October 2017

Predominance of Clostridium difficile 027 during a five-year period in Bolzano, Northern Italy.

Infez Med 2017 Mar;25(1):13-20

Laboratory of Microbiology and Virology, Central Hospital of Bolzano, Italy.

Toxigenic Clostridium difficile is responsible for antibiotic-associated diarrhoea and other diseases. The increasing frequency and severity is attributed to highly-virulent ribotypes such as 027. The aim of the study was to collect epidemiological and molecular data for C. difficile isolates during 2009-2013 in the Central Hospital of Bolzano, Northern Italy. Stool samples from inpatients of the Bolzano Central Hospital were screened for toxins A and B, and C. difficile was cultured and tested for antibiotic susceptibility. PCRs were performed for genes of toxin A, toxin B, binary toxin and ribotyping. During the period 2009-13 from 320 patients (9% of patients tested) at least one stool sample proved positive for C. difficile toxins, and incidences for all hospital inpatients per 10,000 patient days (per 1,000 admissions) varied between 2.2 (1.5) and 4.3 (3.0). Out of 138 isolates (43% of total isolates were studied), 24 different ribotypes were identified. Isolates with ribotype 027 were predominant (38%), followed by 018 (13%) and 607 (10%). Whereas for ribotype 018 a significant decrease was seen during the five-year period, ribotype 027 increased significantly from 0% in 2009 to 64% in 2012, decreasing then to 10% in 2013. Isolates were sensitive to metronidazole and vancomycin, whereas isolates of the three major ribotypes were resistant to moxifloxacin. Our data indicates a significant change in C. difficile incidence rates and ribotype frequencies during the five-year period in the Central Hospital in Bolzano.
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March 2017

Review on colonization of residents and staff in Italian long-term care facilities by multidrug-resistant bacteria compared with other European countries.

Antimicrob Resist Infect Control 2016 11;5:33. Epub 2016 Oct 11.

Dipartimento SCCDP, Unità di Microbiologia e Microbiologia clinica, Pavia, Italy.

Background: Rates of colonization and infection with multidrug-resistant (MDR) bacteria are increasing worldwide, in both acute care hospitals and long-term care facilities (LTCFs). Italy has one of the highest prevalence of MDR bacteria in European countries, especially with regard to methicillin-resistant (MRSA) and extended-spectrum β-lactamase (ESBL) or carbapenemase producing (CPE).

Method: Review of studies on colonization by MDR bacteria from Italian LTCFs, risk factors for colonization and molecular characteristics of surveillance and clinical isolates, compared with other European countries.

Results: High variability of MDR colonization has been reported within and especially between European countries. Only a few surveillance studies have been performed in Italian LTCFs; these show MRSA colonization prevalence of 7.8-38.7 % for residents and 5.2-7.0 % for staff members, ESBL prevalence of 49.0-64.0 % for residents and 5.2-14.5 % for staff and prevalence of CPE of 1.0-6.3 % for residents and 0.0-1.5 % for staff. In Italian LTCFs, as well as in other European countries, the most prevalent ESBLs from surveillance or clinical isolates were found to be CTX-M-type enzymes, particularly CTX-M-15, expressed by the pandemic ST131 clonal group; this lineage also expresses carbapenemase genes of the and types. Various risk factors for colonization of residents by MDR bacteria were identified.

Conclusions: The limited data from Italian LTCFs confirms these settings as important reservoirs for MDR organisms, allowing important considerations regarding the infection risk by these organisms. Nevertheless, more extended and countrywide screening studies for MDR colonization in Italian LTCFs are required. To promote further studies of various microbiological aspects related to LTCFs, the Association of Italian Clinical Microbiologists (Associazione Microbiologi Clinici Italiani; AMCLI) in 2016 has set up a new Working Group for the Study of Infections in LTCFs (Gruppo di Lavoro per lo Studio delle Infezioni nelle Residenze Sanitarie Assistite e Strutture Territoriali assimilabili; GLISTer), consisting of Clinical Microbiologists represented by the authors of this review article.
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http://dx.doi.org/10.1186/s13756-016-0136-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5057254PMC
October 2016

Occurrence of Clostridium difficile infections due to PCR ribotype 027 in Bucharest, Romania.

J Infect Dev Ctries 2014 Jun 11;8(6):694-8. Epub 2014 Jun 11.

National Institute for Infectious Diseases Matei Bals, Bucharest, Romania.

Introduction: Little is known about prevailing ribotypes of Clostridium difficile infection in Romania where CDI is not a mandatory notifiable disease.

Methodology: We studied 64 non-duplicate C. difficile isolates from patients hospitalised at the National Institute of Infectious Diseases, Bucharest, Romania between March 2011 and March 2012.

Results: Sixty-three of the 64 C. difficile isolates produced toxins A and B whereas 44 (69%) isolates produced a binary toxin. Ribotype 027 accounted for 43 (68%) of the 63 toxigenic strains. The remaining 20 isolates belonged to ribotypes 018 (n = 9), 012 (n = 3), and, with one isolate each, 014, 031, 081, 416, 433, 500, 507 and PR03035 (new ribotype). Information on hospital mortality was available for 62 of the 64 patients; among these 62 cases, 4 (6.4%) ended fatal. Recurrence was documented for 11 (18.3%) of the 60 patients for whom this information was available. Multilocus variable-number tandem repeat analysis of the 43 isolates of ribotype 027 yielded a unique cluster for the Romanian isolates when compared to Austrian or Italian isolates.

Conclusion: Our findings sustain the hypothesis of a recent emerged outbreak of C. difficile PCR ribotype 027 infections in the area of Bucharest.
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http://dx.doi.org/10.3855/jidc.4435DOI Listing
June 2014

Antibiotic susceptibility and molecular epidemiology of Panton-Valentine leukocidin-positive meticillin-resistant Staphylococcus aureus: An international survey.

J Glob Antimicrob Resist 2014 Mar 3;2(1):43-47. Epub 2013 Sep 3.

Hôpitaux Universitaires de Genève, Geneva, Switzerland.

The antibiotic susceptibility and molecular epidemiology of Panton-Valentine leukocidin (PVL)-positive meticillin-resistant Staphylococcus aureus (MRSA) isolates reported from 17 countries in the Americas, Europe and, Australia-Asia were analysed. Among a total of 3236 non-duplicate isolates, the lowest susceptibility was observed to erythromycin in all regions. Susceptibility to ciprofloxacin showed large variation (25%, 75% and 84% in the Americas, Europe and Australia-Asia, respectively). Two vancomycin-intermediate PVL-positive MRSA isolates were reported, one from Hong Kong and the other from The Netherlands. Resistance to trimethoprim/sulfamethoxazole and linezolid was <1%. Among 1798 MRSA isolates from 13 countries that were tested for the requested 10 non-β-lactam antibiotics, 49.4% were multisusceptible. However, multiresistant isolates (resistant to at least three classes of non-β-lactam antibiotics) were reported from all regions. Sequence type 30 (ST30) was reported worldwide, whereas ST80 and ST93 were exclusive to Europe and Australia, respectively. USA300 and related clones (ST8) are progressively replacing the ST80 clone in several European countries. Eight major clusters were discriminated by multilocus variable-number tandem repeat assay (MLVA), showing a certain geographic specificity. PVL-positive MRSA isolates frequently remain multisusceptible to non-β-lactam agents, but multiresistance is already prevalent in all regions. Surveillance of MRSA susceptibility patterns should be monitored to provide clinicians with the most current information regarding changes in resistance patterns.
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http://dx.doi.org/10.1016/j.jgar.2013.08.003DOI Listing
March 2014

Changes in colonization of residents and staff of a long-term care facility and an adjacent acute-care hospital geriatric unit by multidrug-resistant bacteria over a four-year period.

Scand J Infect Dis 2014 Feb 17;46(2):114-22. Epub 2013 Dec 17.

From the Reparto di Geriatria , Comprensorio Sanitario di Bolzano , Italy.

Background: In 2012 we undertook a screening study for Enterobacteriaceae with extended-spectrum β-lactamases (ESBLs), derepressed or acquired high-level AmpC cephalosporinases, and metallo-β-lactamases (MBLs), and also methicillin-resistant Staphylococcus aureus (MRSA), in a long-term care facility (LTCF1) and the associated acute care hospital geriatric ward in Bolzano, northern Italy. The study followed up an initial survey carried out in LTCF1 in 2008. For comparison, screening in 2012 was extended to a second LTCF.

Methods: Urine samples and rectal, inguinal, oropharyngeal, and nasal swabs were plated on selective agars. Isolates were typed by pulsed-field gel electrophoresis. Resistance genes and Escherichia coli belonging to ST131 were sought by PCR. Demographic data were collected.

Results: Fewer residents of LTCF1 were colonized with multidrug-resistant (MDR) bacteria in 2012: all MDR organisms, 53.8% vs 74.8% in 2008; ESBL producers, 49.0% vs 64.0% in 2008; MRSA, 13.2% vs 38.7% in 2008; only 2 MBL-producers were isolated in 2012 vs 8 in 2008. Colonization of staff in LTCF1 by MDR bacteria had also decreased (overall 10.5% in 2012 vs 27.5% in 2008). Changed case mixes and risk factors, together with strengthened hygiene measures probably underlie the changes. Colonization proportions in 2012 in LTCF2 were similar to those in LTCF1. By contrast there was no significant change in the proportion of patients colonized by MDR bacteria in the geriatric ward (22.2% in 2008 vs 22.7% in 2012).

Conclusions: A significant decrease in the proportions of staff and residents of an LTCF colonized by MDR bacteria was observed over a 4-y interval.
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http://dx.doi.org/10.3109/00365548.2013.859392DOI Listing
February 2014

Carbapenemase-producing Enterobacteriaceae during 2011-12 in the Bolzano area (Northern Italy): increasing diversity in a low-endemicity setting.

Diagn Microbiol Infect Dis 2013 Dec 11;77(4):354-6. Epub 2013 Oct 11.

Laboratory of Microbiology and Virology, Bolzano Health District, Bolzano, Italy.

The recent (2011-2012) distribution of carbapenemase determinants in Enterobacteriaceae was studied in the Bolzano area (Northern Italy). Low proportions of carbapenemase producers were found for Escherichia coli (0.2%), Citrobacter freundii (1.1%), Klebsiella pneumoniae (1.3%), Klebsiella oxytoca (1.6%) and Enterobacter spp (1.8%). Although VIM-1 remained the most common carbapenemase, the emergence of K. pneumoniae producing KPC-3 and of E. coli producing OXA-48 was observed. Of concern is the spread of the hyperepidemic strains E. coli ST131 producing VIM-1 and K. pneumoniae ST258 producing KPC-3. Low essential and category agreements between the reference broth microdilution and commercial methods were observed for carbapenems.
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http://dx.doi.org/10.1016/j.diagmicrobio.2013.08.029DOI Listing
December 2013

Molecular epidemiology of methicillin-resistant Staphylococcus aureus from bacteraemia in northern Italy.

Infez Med 2012 Dec;20(4):256-64

Laboratorio Aziendale di Microbiologia e Virologia, Comprensorio Sanitario di Bolzano, Italy.

Background: Vancomycin is frequently used in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia; reduced susceptibility to vancomycin is therefore disturbing.

Methods: molecular epidemiological analysis of 81 MRSA bacteraemia isolates collected during 2002-10 in the province of Bolzano, northern Italy was performed. MICs of a range of antimicrobials were determined by agar microdilution, screening for hGISA was by Macro-Etest and Etest GRD and confirmed by PAP-AUC with vancomycin and teicoplanin. All isolates were characterised by toxin gene profiling, agr, spa, and SCCmec-typing; MLST and PFGE were carried out on representative strains.

Results: The dominant clones identified were ST8-MRSA-IVc (55%) and ST228- and ST111-MRSA-I (25%); most of the latter two lineages (19/20; 95%) were GISA or PAP-AUC confirmed hGISA. One ST8-MRSA-IVc isolate harboured ccrA2B2 together with ccrA4B4. The remainder were diverse genotypically and belonged to MLST clonal complexes 1, 22, 45 and 398.

Conclusions: Diverse lineages of MRSA were identified as causing bacteraemia in a province in northern Italy. The association of a specific genotype with the hGISA and GISA phenotypes among representatives of the second most common lineage identified is of clinical concern.
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December 2012

High clonal heterogeneity of Panton-Valentine leukocidin-positive meticillin-resistant Staphylococcus aureus strains from skin and soft-tissue infections in the Province of Bolzano, Northern Italy.

Int J Antimicrob Agents 2012 Jun 3;39(6):522-5. Epub 2012 Apr 3.

Laboratorio Aziendale di Microbiologia e Virologia, Comprensorio Sanitario di Bolzano, Italy.

Panton-Valentine leukocidin (PVL)-positive community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) isolates are widespread in many countries, with varying distribution and epidemiology. The aim of this study was to characterise 10 PVL-positive MRSA isolates collected during February 2010 to January 2011 from skin and soft-tissue infections in the North Italian Province of Bolzano. Accessory gene regulator (agr) typing, staphylococcal cassette chromosome mec (SCCmec) typing, staphylococcal protein A (spa) gene typing, multilocus sequence typing, toxin gene profiling, polymerase chain reaction for type I arginine catabolic mobile element (ACME) and antimicrobial resistance typing were applied to the isolates. Eight different CA-MRSA clones were identified, including ST30-IVc, ST772-V, ST80-IVc, ST5-IVc, ST88-IVa, ST93-IVa, ST8-IVc and the type I ACME-positive ST8-IVa. The high heterogeneity of PVL-positive MRSA probably reflects the introduction of different clones by international travellers or immigrants.
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http://dx.doi.org/10.1016/j.ijantimicag.2012.02.004DOI Listing
June 2012

Dominance of CTX-M group 1 beta-lactamase enzymes in ESBL producing E. coli from outpatient urines in neighboring regions of Austria and Italy.

Wien Klin Wochenschr 2011 Jan 21;123(1-2):41-4. Epub 2011 Jan 21.

Department of Hygiene, Microbiology & Social Medicine, Medical University Innsbruck, Innsbruck, Austria.

The importance of extended spectrum β-lactamases (ESBL) is increasing worldwide. ESBLs of the CTX-M type are on the rise in Europe, not only in the hospital environment but also in outpatients. Therefore we performed a comparative pilot study including ESBL producing Escherichia coli isolated from outpatients suffering from urinary tract infections, 28 from Innsbruck, Austria, and 34 from Bolzano, Italy. Using established PCR methods we detected in nearly 90% of ESBL producing E. coli isolates CTX-M group 1 enzymes and only a few group 2 or group 9 enzymes. bla (TEM), bla (OXA-1) and aminoacyltransferase aac(6')-lb were significantly more frequent in the Austrian region, where also bla (SHV )was found in one isolate. In 2009 the overall prevalence of ESBL in E. coli causing urinary tract infection in outpatient samples was 7.6% in a local laboratory in Innsbruck and 5% in Bolzano. Additionally, we investigated plasmid-mediated qnr genes which can contribute to quinolone resistance, qnrA was found in an AmpC producing E. coli from Innsbruck and qnrS in two ESBL producers from Bolzano. Data confirmed that ESBL-producing E. coli have emerged as important pathogens in urinary tract infections of outpatients in both regions.
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http://dx.doi.org/10.1007/s00508-010-1527-6DOI Listing
January 2011

Complete nucleotide sequence of the IncN plasmid pKOX105 encoding VIM-1, QnrS1 and SHV-12 proteins in Enterobacteriaceae from Bolzano, Italy compared with IncN plasmids encoding KPC enzymes in the USA.

J Antimicrob Chemother 2010 Oct 22;65(10):2070-5. Epub 2010 Jul 22.

Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanita, Rome, Italy.

Objectives: We determined the complete nucleotide sequence of pKOX105, a 54 641 bp plasmid from a Klebsiella oxytoca strain that was isolated from a resident of a long-term-care facility in Bolzano, Italy.

Methods: The plasmid was sequenced using a shotgun approach. Combinatorial PCRs, directed PCRs and walking reads were used to assemble the contigs and to fill in gaps. Gene sequences were compared with reference plasmids and aligned with GenBank data using BLAST and CLUSTAL W software.

Results: pKOX105 belonged to incompatibility group IncN, harboured bla(VIM-1), bla(SHV-12), qnrS1, aacA4 and dfrA14 and conferred resistance to carbapenems, oxyimino-cephalosporins, quinolones, aminoglycosides and trimethoprim. It was highly related to the p9 and p12 plasmids from Klebsiella pneumoniae and K. oxytoca strains isolated at a New York City hospital in 2005 carrying bla(KPC-2) and bla(KPC-3), respectively.

Conclusions: IncN plasmids are broad host-range plasmids that have contributed significantly to the worldwide dissemination of many different resistance genes in Enterobacteriaceae from animal and human sources. This plasmid family is now playing a crucial role in the global spread of diverse carbapenemase genes in Klebsiella spp.
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http://dx.doi.org/10.1093/jac/dkq269DOI Listing
October 2010

Linkage of acquired quinolone resistance (qnrS1) and metallo-beta-lactamase (blaVIM-1) genes in multiple species of Enterobacteriaceae from Bolzano, Italy.

J Antimicrob Chemother 2008 Mar 8;61(3):515-23. Epub 2008 Jan 8.

Laboratorio Interaziendale di Microbiologia e Virologia, Via Amba Alagi 5, I-39100 Bolzano, Italy.

Objectives: Twenty-four of 209 oxyimino-cephalosporin- and/or aztreonam-resistant Enterobacteriaceae collected around Bolzano had reduced susceptibility or resistance to carbapenems and gave positive metallo-beta-lactamase (MBL) tests. Their resistance mechanisms were investigated.

Methods: Resistances were identified by Vitek 2 and MIC tests and isolates were genotyped by PFGE. Resistance genes were identified by PCR and sequencing, and plasmids were transferred by conjugation and/or transformation. Plasmid-borne genes were identified by Southern blotting, and their genetic surroundings were investigated by PCR mapping.

Results: The 24 isolates with positive EDTA/imipenem synergy tests had bla(VIM-1) carried on 40-150 kb plasmids. Imipenem MICs ranged from 2 to >32 mg/L, while those of meropenem and ertapenem were lower. The isolates included a clonal cluster of 10 Klebsiella pneumoniae, two other K. pneumoniae isolates, and diverse isolates of Escherichia coli (seven), Klebsiella oxytoca (three) and Citrobacter freundii (two). Six MBL producers were aztreonam-susceptible; the 18 aztreonam-resistant isolates had co-resident extended-spectrum beta-lactamases. bla(VIM-1) occurred as the first cassette in class 1 integrons, with aacA4 as the second cassette. Quinolone resistance gene qnrS1 was detected in 21 of 24 (87.5%) bla(VIM-1)-positive isolates versus 14 of 185 (7.6%) bla(VIM)-negative isolates (P < 0.0001), with 13 of the latter belonging to a clonal cluster of E. coli. qnrS1 was located on the same plasmids as bla(VIM-1) and aacA4, but was not closely linked, as judged by PCR mapping.

Conclusions: bla(VIM-1) has become disseminated among enterobacteria in a small Italian town. The frequent association of genes conferring carbapenem, aminoglycoside and quinolone resistance on single plasmids will facilitate co-selection.
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http://dx.doi.org/10.1093/jac/dkm508DOI Listing
March 2008
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