Publications by authors named "Na Ra Yun"

66 Publications

Comparison of RT-PCR, RT-nested PCRs, and real-time PCR for diagnosis of severe fever with thrombocytopenia syndrome: a prospective study.

Sci Rep 2021 Aug 18;11(1):16764. Epub 2021 Aug 18.

Department of Internal Medicine, School of Medicine, Pusan National University, Pusan, Republic of Korea.

We designed a highly sensitive reverse transcription nested polymerase chain reaction targeting the M-segment (NPCR-M) of severe fever with thrombocytopenia syndrome (SFTS) virus. NPCR-M was performed in parallel with three other referenced PCR assays QPCR-S, PCR-M, and NPCR-S to assess their clinical usefulness as routine diagnostic techniques for SFTS. In this multi-centered prospective study, 122 blood samples from 38 laboratory-confirmed SFTS patients and 85 control samples were used. The results demonstrated that QPCR-S and NPCR-S had better sensitivity rate up to 21 days after symptom onset however, the PCR-M showed poor sensitivity after 7 days of symptom onset. Our designed NPCR-M had a higher detection rate up to 40 days from symptom onset and revealed the persistence of SFTSV RNA in the early convalescent phase. No false-positive results were seen for the control samples. Additionally, NPCR-M showed positive results for a sample that initially showed negative results from other PCRs and for many other samples collected in the convalescent phase of SFTS. Our designed nested PCR is suitable for SFTSV detection in patients' blood collected in the acute and early convalescent phase of SFTS, and shows better sensitivity and high specificity even up to 40 days after symptom onset.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-96066-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8373928PMC
August 2021

Utility of Nested Reverse-Transcriptase Polymerase Chain Reaction of Clinical Specimens for Early Diagnosis of Hemorrhagic Fever with Renal Syndrome.

Am J Trop Med Hyg 2021 Aug 9. Epub 2021 Aug 9.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Hemorrhagic fever with renal syndrome (HFRS) is confirmed by the isolation of hantavirus from serum, detection of virus-specific IgM, or a four-fold change in IgG titers during the acute and convalescent periods measured using an immunofluorescence assay (IFA). However, these tests are inefficient for early diagnosis. Therefore, this study investigated the usefulness of reverse-transcriptase nested polymerase chain reaction (RT-nPCR) for early diagnosis of HFRS using clinical samples such as urine and serum. Electronic medical records of eight patients with confirmed HFRS using IFA and RT-nPCR between May 2016 and May 2020 at Chosun University Hospital were reviewed. The virus was detected in all patients using RT-nPCR targeting the large (L) segment of hantavirus during the early phase in urine and serum. Importantly, the virus was identified in urine at a time when it was not identified in serum. Additionally, the virus was detected in urine and serum for up to 1 month after initial presentation with illness, but not in saliva, using RT-nPCR. We report eight HFRS cases diagnosed using urine and serum, but not using saliva, with RT-nPCR targeting the L-segment. Hantavirus RNA detection by RT-nPCR in urine and serum may aid the rapid diagnosis of HFRS during the early phase of the disease. In particular, HFRS should not be ruled out based on negative RT-PCR results in serum, and RT-PCR should be performed using urine as well as serum during the early phase of symptoms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.21-0185DOI Listing
August 2021

Clinical Usefulness of Nested Reverse-Transcription Polymerase Chain Reaction for the Diagnosis of Severe Fever with Thrombocytopenia Syndrome.

Am J Trop Med Hyg 2021 Aug 2. Epub 2021 Aug 2.

Department of Internal Medicine, Chosun University, Gwangju, South Korea.

Severe fever with thrombocytopenia syndrome (SFTS), caused by SFTS virus (SFTSV) is an emerging tick-borne infectious disease. Few studies have assessed the clinical usefulness of nested reverse-transcription polymerase chain reaction (RT-PCR) for diagnosing SFTS. We performed conventional RT-PCR targeting the M segment, nested RT-PCR targeting M and S segments, and real-time RT-PCR targeting the S segment of SFTSV for four patients with suspected SFTS. Although conventional RT-PCR results for the first two patients were negative at admission, nested RT-PCR using the S or M targets was positive for the same samples. Likewise, in the other two patients, initial samples were confirmed positive in all three tests, but follow-up testing demonstrated negative conventional RT-PCR and positive nested RT-PCR results. Thus, delayed testing using conventional RT-PCR or real-time RT-PCR in symptomatic patients with SFTS may result in missed diagnoses, and compared with these methods, nested RT-PCR may increase the window for obtaining positive SFTSV PCR results. Meanwhile, the indirect immunofluorescence assay showed seroconversion to SFTSV antibodies in all four patients. Nested RT-PCR for SFTSV M and S segments could help diagnose SFTS in patients testing negative by conventional RT-PCR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.21-0183DOI Listing
August 2021

Molecular detection and identification of Culex flavivirus in mosquito species from Jeju, Republic of Korea.

Virol J 2021 07 19;18(1):150. Epub 2021 Jul 19.

Department of Clinical Laboratory Science, Gwangju Health University, Gwangju, Republic of Korea.

Background: Mosquito-borne flaviviruses are prime pathogens and have been a major hazard to humans and animals. They comprise several arthropod-borne viruses, including dengue virus, yellow fever virus, Japanese encephalitis virus, and West Nile virus. Culex flavivirus (CxFV) is a member of the insect-specific flavivirus (ISF) group belonging to the genus Flavivirus, which is widely distributed in a variety of mosquito populations.

Methods: Viral nucleic acid was extracted from adult mosquito pools and subjected to reverse transcriptase nested polymerase chain reaction (PCR) using target-specific primers for detecting CxFV nonstructural protein 5 (NS5). The PCR-positive samples were then sequenced, and a phylogenetic tree was constructed, including reference sequences obtained from GenBank.

Results: 21 pools, belonging to Culex pipiens pallens (Cx. p. pallens) were found to be positive for the CxFV RNA sequence, with a minimum infection rate of 14.5/1000 mosquitoes. The phylogenetic analysis of the NS5 protein sequences indicated that the detected sequences were closely related to strains identified in China, with 95-98% sequence similarities.

Conclusion: Our findings highlight the presence of CxFV in Cx. p. pallens mosquito species in Jeju province, Republic of Korea. This is the first study reporting the prevalence of CxFV in Culex Pipiens (Cx. pipiens) host in the Jeju province, which can create possible interaction with other flaviviruses causing human and animal diseases. Although, mosquito-borne disease causing viruses were not identified properly, more detailed surveillance and investigation of both the host and viruses are essential to understand the prevalence, evolutionary relationship and genetic characteristic with other species.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12985-021-01618-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8287664PMC
July 2021

Clinical usefulness of 16S ribosomal RNA real-time PCR for the diagnosis of scrub typhus.

Sci Rep 2021 Jul 12;11(1):14299. Epub 2021 Jul 12.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Scrub typhus is a major acute febrile disease in the Asia-Pacific region. The purpose of the present study is to investigate the clinical usefulness of real-time PCR (Q-PCR) of 16S rRNA for the diagnosis of scrub typhus. We examined blood specimens from 148 adult patients who were confirmed to have scrub typhus from September 2008 to December 2009. Among the 148 scrub typhus patients, 36 patients were treated with antibiotics before admission. To evaluate the clinical usefulness of 16S rRNA Q-PCR, we compared its diagnostic accuracy to the accuracy of the following methods: nested PCR (N-PCR) targeting the gene encoding the 56-kDa protein, Q-PCR targeting the gene encoding the 47-kDa protein, and conventional PCR (C-PCR), targeting the 16S rRNA gene. According to 16S rRNA Q-PCR and 47-kDa Q-PCR, the mild group had copy numbers of 234.4 ± 261.9 and 130.5 ± 128.3, whereas the severe group had copy numbers of 584.4 ± 911.4 and 244.7 ± 210.9, respectively. In both tests, the mean copy numbers were significantly greater in the severe group (P = 0.037 and P = 0.035). 16S rRNA Q-PCR detected Orientia tsutsugamushi infections with a sensitivity of 91.9% (95% CI 86.3-95.7), and 56-kDa N-PCR, 47-kDa Q-PCR, and 16S rRNA C-PCR exhibited lower sensitivities of 81.1% (95% CI 73.8-87.0), 74.3% (95% CI 66.5-81.1), and 87.8% (95% CI 81.5-92.6), respectively, for all 148 patients. In addition, 16S rRNA Q-PCR exhibited a sensitivity of 99.1% (95% CI 95.1-100.0) in the 112 patients who were not treated with antibiotics before admission. 16S rRNA Q-PCR is clinically useful for the rapid diagnosis of scrub typhus and is more accurate than the 56-kDa N-PCR, 47-kDa Q-PCR, and 16S C-PCR methods.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-93541-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8275794PMC
July 2021

Acute Appendicitis Associated with Hantaan Virus Infection.

Am J Trop Med Hyg 2021 Jul 6. Epub 2021 Jul 6.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Hantaviruses are Bunyaviridae viruses that cause hemorrhagic fever with renal syndrome (HFRS). Appendicitis caused by Hantaan virus has not been reported previously. An 81-year-old man who underwent laparoscopic appendectomy for suspected appendicitis based on abdominal pain, fever, hypotension, and computed tomography findings. Based on a suspicion of hemorrhagic fever with renal syndrome, the patient's plasma was simultaneously analyzed using an indirect immunofluorescent antibody assay and nested reverse transcription-polymerase chain reaction (RT-PCR). The appendix tissue was also analyzed using nested RT-PCR and immunohistochemical (IHC) staining to identify the presence of Hantaan virus. Nested RT-PCR detected the presence of Hantaan virus, and indirect immunofluorescent antibody assay results revealed the presence of elevated antibody levels. Furthermore, IHC staining of the appendix tissue confirmed Hantaan virus antigens in the peripheral nerve bundle. Based on these findings, we confirmed the nerve tropism of the Hantaan virus. Hantaan virus in plasma and appendix tissue samples was confirmed using PCR and phylogenetic tree analysis. Moreover, we detected hypertrophy of the submucosa and periappendiceal adipose tissue nerve bundle along with Hantaan virus antigens in peripheral nerve bundles using IHC staining. Hence, we report that Hantaan virus infection may be accompanied by appendicitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.20-1468DOI Listing
July 2021

Molecular investigation of tick-borne pathogens in ticks removed from tick-bitten humans in the southwestern region of the Republic of Korea.

PLoS One 2021 15;16(6):e0252992. Epub 2021 Jun 15.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

In this study, we investigated the presence of tick-borne pathogens in ticks removed from tick-bitten humans in the southwestern provinces of the Republic of Korea (ROK). We identified 33 ticks from three tick species, namely Amblyomma testudinarium (60.6%), Haemaphysalis longicornis (27.3%), and Ixodes nipponensis (12.1%) in order of occurrence via morphology and 16S rDNA-targeting polymerase chain reaction (PCR). Tick-borne pathogens were detected in 16 ticks using pathogen-specific PCR. From the results, 12 ticks (36.4%) tested positive for spotted fever group (SFG) Rickettsia: Rickettsia monacensis (1/12), R. tamurae (8/12), and Candidatus Rickettsia jingxinensis (3/12). Three ticks (9.1%) were positive for Anaplasma phagocytophilum. In addition, three ticks (9.1%) tested positive for Babesia gibsoni (1/3) and B. microti (2/3). In conclusion, we identified three tick species; the most common species was A. testudinarium, followed by H. longicornis and I. nipponensis. SFG Rickettsia, A. phagocytophilum, and Babesia spp. were the most frequently detected pathogens in ticks removed from tick-bitten humans. To our knowledge, this is the first report of R. tamurae and Ca. R. jingxinensis detection in Korea. The present results will contribute to the understanding of tick-borne infections in animals and humans in the ROK.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0252992PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8205137PMC
June 2021

Human granulocytic anaplasmosis in a Single University Hospital in the Republic of Korea.

Sci Rep 2021 May 25;11(1):10860. Epub 2021 May 25.

Department of Internal Medicine, Chosun University College of Medicine, 588 Seosuk-dong, Dong-gu, Gwangju, 501-717, South Korea.

To date, only a few studies have analyzed the clinical characteristics and genetic features of human granulocytic anaplasmosis (HGA) in South Korea. Thus, in this study, we investigated the clinical characteristics of HGA and methods used for clinical diagnosis. The clinical characteristics of patients with HGA were studied retrospectively. We reviewed the medical charts of 21 confirmed patients with HGA admitted to the Chosun University Hospital, located in Gwangju, South Korea. Twenty-one HGA patients visited the hospital 2-30 days (median 7 days) after the onset of symptoms. Fourteen patients (66.7%) had fever, which was alleviated 2 h (range 0-12.75 h) after starting treatment with doxycycline. Of the 18 patients who underwent peripheral blood (PB) smear test, only one (5.6%) had morulae. Additionally, only 4/17 patients (23.5%) had morulae in the PB smear reconducted after the confirmation of anaplasmosis. All 21 patients recovered without significant complications. As per results of the blood tests conducted at the time of admission, 7/21 (33.3%) and 5/21 (23.8%) patients showed at least 1:16 and 1:80 of IgM and IgG titers, respectively. Most HGA patients in Korea recovered without significant complications. The indirect immunofluorescence antibody diagnosis or morulae identification for HGA in this study had low sensitivity in the early stage of the disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-90327-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8149831PMC
May 2021

Risk Factors and a Scoring System to Predict ARDS in Patients with COVID-19 Pneumonia in Korea: A Multicenter Cohort Study.

Dis Markers 2021 9;2021:8821697. Epub 2021 Apr 9.

Department of Infectious Diseases, Chonnam National University Hospital, Gwangju, Republic of Korea.

Predictive studies of acute respiratory distress syndrome (ARDS) in patients with coronavirus disease 2019 (COVID-19) are limited. In this study, the predictors of ARDS were investigated and a score that can predict progression to ARDS in patients with COVID-19 pneumonia was developed. All patients who were diagnosed with COVID-19 pneumonia between February 1, 2020, and May 15, 2020, at five university hospitals in Korea were enrolled. Their demographic, clinical, and epidemiological characteristics and the outcomes were collected using the World Health Organization COVID-19 Case Report Form. A logistic regression analysis was performed to determine the predictors for ARDS. The receiver operating characteristic (ROC) curves were constructed for the scoring model. Of the 166 patients with COVID-19 pneumonia, 37 (22.3%) patients developed ARDS. The areas under the curves for the infiltration on a chest X-ray, C-reactive protein, neutrophil/lymphocyte ratio, and age, for prediction of ARDS were 0.91, 0.90, 0.87, and 0.80, respectively (all < 0.001). The COVID-19 ARDS Prediction Score (CAPS) was constructed using age (≥60 years old), C-reactive protein (≥5 mg/dL), and the infiltration on a chest X-ray (≥22%), with each predictor allocated 1 point. The area under the curve of COVID-19 ARDS prediction score (CAPS) for prediction of ARDS was 0.90 (95% CI 0.86-0.95; < 0.001). It provided 100% sensitivity and 75% specificity when the CAPS score cutoff value was 2 points. CAPS, which consists of age, C-reactive protein, and the area of infiltration on a chest X-ray, was predictive of the development of ARDS in patients with COVID-19 pneumonia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2021/8821697DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8052177PMC
April 2021

Evaluation of the Diagnostic Accuracy of Antibody Assays for Patients with Scrub Typhus.

J Clin Microbiol 2021 06 18;59(7):e0294220. Epub 2021 Jun 18.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

This study was carried out to evaluate the accuracy of various antibody tests for scrub typhus, namely, the indirect immunofluorescence assay (IFA) from the Korea Centers for Disease Control and Prevention (KCDC) and four commercial kits (companies A to D). The test accuracy was based on the diagnosis of scrub typhus, as defined by a positive PCR or culture. In total, serum samples from 97 patients with scrub typhus and 200 non-scrub typhus patients were tested. The respective sensitivity and specificity of each test were as follows. For the KCDC IFA, sensitivity and specificity were 55.7% (95% confidence interval [CI], 45.2 to 65.8%) and 94.8% (95% CI, 90.4 to 97.3%) for IgM and 42.3% (95% CI, 32.3 to 52.7%) and 96.3% (95% CI, 92.6 to 98.5%) for IgG, with diagnostic cutoffs of ≥1:16 for IgM and ≥1:256 for IgG. For kit A, the sensitivity and specificity were 70.1% (95% CI, 59.8 to 78.8%) and 74.6% (95% CI, 67.6 to 80.6%) for total immunoglobulins, with a cutoff of ≥1:40. For kit B, the sensitivity and specificity were 64.3% (95% CI, 51.9 to 75.1%) and 94.9% (95% CI, 81.4 to 99.1%) for IgM and 67.1% (95% CI, 54.8 to 77.6%) and 74.4% (95% CI, 57.6 to 86.4%) for IgG. For kit C, the sensitivity and specificity were 53.6% (95% CI, 43.2 to 63.7%) and 99.5% (95% CI, 96.8 to 100%) for IgM and 36.1% (95% CI, 26.8 to 46.5%) and 100% (95% CI, 97.6 to 100%) for IgG. For kit D, the sensitivity and specificity were 73.2% (95% CI, 63.1 to 81.4%) and 89.5% (95% CI, 84.2 to 93.2%) for total immunoglobulins. These results are all unsatisfactory, highlighting an urgent need for the development of more highly sensitive and specific tests.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JCM.02942-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8218765PMC
June 2021

First report of the molecular detection of human pathogen Rickettsia raoultii in ticks from the Republic of Korea.

Parasit Vectors 2021 Apr 7;14(1):191. Epub 2021 Apr 7.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Background: Rickettsial diseases associated with the spotted fever group constitute a growing number of newly identified Rickettsia pathogens and their tick vectors in various parts of the world. At least 15 distinct tick species belonging to six genera have shown the presence of Rickettsia raoultii. Herein, we report the detection of R. raoultii in ticks from the Republic of Korea (ROK).

Methods: Thirty-five ticks were collected from 29 patients with tick bites in Gwangju Metropolitan City, Jeollanam Province, ROK. The ticks were identified using molecular, morphological, and taxonomic characteristics. All samples were screened for presence of Rickettsia species using nested polymerase chain reactions of their outer membrane protein (ompA) and citrate synthase (gltA) genes. The amplified products were sequenced for subsequent phylogenetic analyses.

Results: Sequencing data showed the DNA sequences of R. raoultii in three Haemaphysalis longicornis ticks. All three tick samples were 99.4-100% similar to previously reported partial sequences of ompA of R. raoultii strains CP019435 and MF002523, which formed a single clade with the reference strains.

Conclusions: We provide the first description and molecular identification of R. raoultii detected in H. longicornis ticks in the ROK. This observation extends the geographical distribution of R. raoultii. Screening of human samples for this pathogen will provide information about the prevalence of rickettsial infections in this region.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13071-021-04695-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8025568PMC
April 2021

The Effect of Long-lasting Permethrin Impregnated Socks on Tick Bite in Korea.

J Korean Med Sci 2021 Feb 22;36(7):e49. Epub 2021 Feb 22.

Department of Preventive Medicine, College of Medicine, Chosun University, Gwangju, Korea.

Background: The risk of tick-borne diseases is decreased by increasing awareness and knowledge through prevention education. The aim of the present study was to evaluate the effect of long-lasting permethrin impregnated (LLPI) socks for tick bites.

Methods: A randomized open label study was conducted to determine the effectiveness of LLPI socks for prevention of tick bites among 367 adults living in a rural area. Participants completed questionnaires at the start of follow-up (July 2014) and at the end of follow-up (December 2014), and tick bites were reported.

Results: A total of 332 subjects completed the follow-up survey. The tick bite rate of the two groups was not significantly different (3.6% vs. 3.1%). But the tick bite rate of lower extremities of subjects wearing LLPI socks was significantly lower compared to that of subjects wearing general socks.

Conclusion: The tick bite rate was not different between the two groups, but the tick bite rate of lower extremities of LLPI was significantly lower than general groups. Further study is needed to investigate the effect of LLPI clothes with larger populations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3346/jkms.2021.36.e49DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900532PMC
February 2021

Effects of steroid therapy in patients with severe fever with Thrombocytopenia syndrome: A multicenter clinical cohort study.

PLoS Negl Trop Dis 2021 02 19;15(2):e0009128. Epub 2021 Feb 19.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an acute, febrile, and potentially fatal tick-borne disease caused by the SFTS Phlebovirus. Here, we evaluated the effects of steroid therapy in Korean patients with SFTS.

Methods: A retrospective study was performed in a multicenter SFTS clinical cohort from 13 Korean university hospitals between 2013 and 2017. We performed survival analysis using propensity score matching of 142 patients with SFTS diagnosed by genetic or antibody tests.

Results: Overall fatality rate was 23.2%, with 39.7% among 58 patients who underwent steroid therapy. Complications were observed in 37/58 (63.8%) and 25/83 (30.1%) patients in the steroid and non-steroid groups, respectively (P < .001). Survival analysis after propensity score matching showed a significant difference in mean 30-day survival time between the non-steroid and steroid groups in patients with a mild condition [Acute Physiology and Chronic Health Evaluation II (APACHE II) score <14; 29.2 (95% CI 27.70-30.73] vs. 24.9 (95% CI 21.21-28.53], P = .022]. Survival times for the early steroid (≤5 days from the start of therapy after symptom onset), late steroid (>5 days), and non-steroid groups, were 18.4, 22.4, and 27.3 days, respectively (P = .005).

Conclusions: After steroid therapy, an increase in complications was observed among patients with SFTS. Steroid therapy should be used with caution, considering the possible negative effects of steroid therapy within 5 days of symptom onset or in patients with mild disease (APACHE II score <14).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pntd.0009128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7928499PMC
February 2021

Follow-up investigation of antibody titers and diagnostic antibody cutoff values in patients with scrub typhus in South Korea.

BMC Infect Dis 2021 Jan 13;21(1):69. Epub 2021 Jan 13.

Departments of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Background: Scrub typhus is a mite-borne infectious disease caused by Orientia tsutsugamushi. Few follow-up studies have assessed antibody titers using serologic tests from various commercial laboratories and the Korea Centers for Disease Control and Prevention (KCDC).

Methods: A prospective study to assess the antibody titers in patients with scrub typhus and seroprevalence in individuals undergoing health checkups was conducted using results of immunofluorescence antibody assays (IFAs) and serologic tests, used by the KCDC and commercial laboratories, respectively. The following tests were performed simultaneously: (i) indirect IFA used by the KCDC to detect immunoglobulin (Ig) M and IgG, (ii) IFA used by a commercial laboratory to detect total Ig, and (iii) antibody tests using two commercially available kits.

Results: When the IgM and IgG cutoff values (≥1:16 and ≥1:256, respectively) used in the IFA and the total IgG cutoff values (≥1:40) were used in prospective follow-up investigations, the antibody positivity rates of 102 patients with scrub typhus were 44.1, 35.3, and 57.6%, respectively, within 5 days of symptom onset. Among 91 individuals who recovered from scrub typhus, the follow-up IgM, IgG, and total Ig positivity rates for 13 years were 37.4% (34/91), 22.0% (20/91), and 76.9% (70/91), respectively. Among 216 individuals undergoing health checkups, the seroprevalence of IgM was 4.2% (9/216); no seroprevalence of IgG was observed.

Conclusions: IFAs used by the KCDC and the commercial laboratory and rapid commercial kits could not distinguish between patients who had recovered from scrub typhus and those who are currently infected with O. tsutsugamushi. In South Korea and other countries, where low antibody cutoff values are used, upward adjustments of cutoff values may be necessary.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12879-020-05735-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7807423PMC
January 2021

A case of SFTS coinfected with E. coli bacteremia.

BMC Infect Dis 2021 Jan 7;21(1):25. Epub 2021 Jan 7.

Graduate School of Chosun University, Gwangju, Republic of Korea.

Background: Severe fever thrombocytopenia syndrome virus (SFTSV) is the causative agent of severe fever thrombocytopenia syndrome (SFTS). SFTS is an emerging infectious disease, characterized by high fever, gastrointestinal symptoms, leukopenia, thrombocytopenia, and a high mortality rate. Until now, little importance has been given to the association of SFTS with leukocytosis and bacterial co-infection.

Case Presentation: A 51-year old man visited our hospital with fever and low blood pressure. He was a farmer by occupation and often worked outdoors. He had a Foley catheter inserted due to severe BPH. Laboratory tests revealed thrombocytopenia, elevated liver function, and elevated CRP levels. He had marked leukocytosis, proteinuria, hematuria, and conjunctival hemorrhage. Initially, we thought that the patient was suffering from hemorrhagic fever with renal syndrome (HFRS). However, we confirmed SFTS through PCR and increasing antibody titer. However, his blood culture also indicated E. coli infection.

Conclusion: SFTS displays characteristics of fever, thrombocytopenia, elevated liver function, and leukocytopenia. We described a case of SFTS with leukocytosis due to coinfection with E. coli. Since patients with SFTS usually have leukocytopenia, SFTS patients with leukocytosis are necessarily evaluated for other causes of leukocytosis. Here, we report the first case of an SFTS with concurrent E. coli bacteremia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12879-020-05705-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7792358PMC
January 2021

Orientia tsutsugamushi DNA load and genotypes in blood as a marker of severity.

Acta Trop 2021 Mar 9;215:105786. Epub 2020 Dec 9.

Departments of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi and is endemic to many parts of the Asia-Pacific region. We investigated whether the genotype of O. tsutsugamushi or the DNA load would be a useful marker of disease severity in scrub typhus patients. We evaluated the clinical features, genotypes and bacterial DNA load in the blood of 118 patients, including 114 surviving and 4 non-surviving patients, admitted at Chosun University Hospital. Four patients infected with the Pajoo, Yonchon, Youngworl and Boryong genotypes died. In the 114 survivors, 100 Boryong and 2 Taguchi genotypes were identified. The genotypes involved showed significant differences between the surviving and non-surviving patients (p<0.001). The median number of O. tsutsugamushi DNA copies was 78 copies /μL (range 3,960) in surviving patients, whereas 83,800 copies/μL (range 244,600) in the non-surviving patients. We found that the genotype and DNA load in the patient's blood are useful markers of disease severity in scrub typhus.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.actatropica.2020.105786DOI Listing
March 2021

First identification of Anaplasma phagocytophilum in both a biting tick Ixodes nipponensis and a patient in Korea: a case report.

BMC Infect Dis 2020 Nov 11;20(1):826. Epub 2020 Nov 11.

Department of Internal Medicine, College of Medicine, Dong-A University, Busan, Republic of Korea.

Background: Human granulocytic anaplasmosis (HGA) is a tick-borne infectious disease caused by Anaplasma phagocytophilum. To date, there have been no reported cases of A. phagocytophilum infection found in both the biting tick and the patient following a tick bite.

Case Presentation: An 81-year-old woman presented with fever following a tick bite, with the tick still intact on her body. The patient was diagnosed with HGA. The tick was identified as Ixodes nipponensis by morphological and molecular biological detection methods targeting the 16S rRNA gene. The patient's blood was cultured after inoculation into the human promyelocytic leukemia cell line HL-60. A. phagocytophilum growth was confirmed via culture and isolation. A. phagocytophilum was identified in both the tick and the patient's blood by Anaplasma-specific groEL- and ankA-based nested polymerase chain reaction followed by sequencing. Moreover, a four-fold elevation in antibodies was observed in the patient's blood.

Conclusion: We report a case of a patient diagnosed with HGA following admission for fever due to a tick bite. A. phagocytophilum was identified in both the tick and the patient, and A. phagocytophilum was successfully cultured. The present study suggests the need to investigate the possible incrimination of I. nipponensis as a vector for HGA in Korea.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12879-020-05522-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7656494PMC
November 2020

Usefulness of Nested Polymerase Chain Reaction with Clinical Specimens for Diagnosis of Leptospirosis: a Case Series and a Review of Literature.

J Korean Med Sci 2020 Sep 14;35(36):e301. Epub 2020 Sep 14.

Department of Infectious Diseases, Chosun University Hospital, Gwangju, Korea.

A culture of the species and the microscopic agglutination test (MAT) are considered as the reference standard for the diagnosis of leptospirosis, but both tests are imperfect for early diagnosis. We describe 4 patients diagnosed with leptospirosis using nested polymerase chain reaction (N-PCR) that targeted the 16S rRNA gene and the passive hemagglutination assay (PHA). In our 4 cases, DNA in the urine, plasma, or cerebrospinal fluid (CSF), was detected by N-PCR in the early phase of leptospirosis, except in the sample from the buffy coat. Especially, case 3 showed that N-PCR with the urine and CSF was positive 8 days after symptom onset, but not for the plasma or buffy coat. We report 4 cases of leptospirosis that were diagnosed by N-PCR that targeted the 16S rRNA gene with urine, plasma, or CSF, but not the buffy coat. Three were cured by doxycycline but the case 4 was fatal. Detection of DNA by PCR from the urine and CSF, in addition to plasma, may be helpful to confirm the diagnosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3346/jkms.2020.35.e301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7490198PMC
September 2020

Asymptomatic-anaplasmosis confirmation using genetic and serological tests and possible coinfection with spotted fever group Rickettsia: a case report.

BMC Infect Dis 2020 Jun 30;20(1):458. Epub 2020 Jun 30.

Departments of Internal Medicine, College of Medicine, Chosun University, 588 Seosuk-dong, Dong-gu, Gwangju, 61453, Republic of Korea.

Background: Anaplasmosis is an emerging acute febrile disease that is caused by a bite of an Anaplasma phagocytophilum-infected hard tick. As for healthy patients, reports on asymptomatic anaplasmosis resulting from such tick bites are rare.

Case Presentation: A 55-year-old female patient visited the hospital with a tick bite in the right infraclavicular region. The tick was suspected to have been on the patient for more than 10 days. PCR and an indirect immunofluorescence assay (IFA) were performed to identify tick-borne infectious diseases. The blood sample collected at admission yielded a positive result in nested PCR targeting Ehrlichia- or Anaplasma-specific genes groEL and ankA. Subsequent sequencing confirmed the presence of A. phagocytophilum, and seroconversion was confirmed by the IFA involving an A. phagocytophilum antigen slide. PCR detected no Rickettsia-specific genes [outer membrane protein A (ompA) or surface cell antigen 1 (sca1)], but seroconversion of spotted fever group (SFG) rickettsiosis was confirmed by an IFA.

Conclusions: This study genetically and serologically confirmed an asymptomatic A. phagocytophilum infection. Although SFG rickettsiosis was not detected genetically, it was detected serologically. These findings indicate the possibility of an asymptomatic coinfection: anaplasmosis plus SFG rickettsiosis. It is, therefore, crucial for clinicians to be aware of potential asymptomatic anaplasmosis following a tick bite.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12879-020-05170-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7325360PMC
June 2020

Clinical Course and Outcomes of Patients with Severe Acute Respiratory Syndrome Coronavirus 2 Infection: a Preliminary Report of the First 28 Patients from the Korean Cohort Study on COVID-19.

J Korean Med Sci 2020 Apr 6;35(13):e142. Epub 2020 Apr 6.

Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pneumonia emerged in Wuhan, China in December 2019. In this retrospective multicenter study, we investigated the clinical course and outcomes of novel coronavirus disease 2019 (COVID-19) from early cases in Republic of Korea.

Methods: All of the cases confirmed by real time polymerase chain reaction were enrolled from the 1st to the 28th patient nationwide. Clinical data were collected and analyzed for changes in clinical severity including laboratory, radiological, and virologic dynamics during the progression of illness.

Results: The median age was 40 years (range, 20-73 years) and 15 (53.6%) patients were male. The most common symptoms were cough (28.6%) and sore throat (28.6%), followed by fever (25.0%). Diarrhea was not common (10.7%). Two patients had no symptoms. Initial chest X-ray (CXR) showed infiltration in 46.4% of the patients, but computed tomography scan confirmed pneumonia in 88.9% (16/18) of the patients. Six patients (21.4%) required supplemental oxygen therapy, but no one needed mechanical ventilation. Lymphopenia was more common in severe cases. Higher level of C-reactive protein and worsening of chest radiographic score was observed during the 5-7 day period after symptom onset. Viral shedding was high from day 1 of illness, especially from the upper respiratory tract (URT).

Conclusion: The prodromal symptoms of COVID-19 were mild and most patients did not have limitations of daily activity. Viral shedding from URT was high from the prodromal phase. Radiological pneumonia was common from the early days of illness, but it was frequently not evident in simple CXR. These findings could be plausible explanations for the easy and rapid spread of SARS-CoV-2 in the community.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3346/jkms.2020.35.e142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7131901PMC
April 2020

Scalp eschar and neck lymphadenopathy after tick bite (SENLAT) caused by Bartonella henselae in Korea: a case report.

BMC Infect Dis 2020 Mar 12;20(1):216. Epub 2020 Mar 12.

Division of Bacterial Disease Research, Center for Infectious Disease Research, Korea National Institute of Health, Chungcheongbuk-do, Korea.

Background: Tick-borne lymphadenopathy (TIBOLA) is an infectious disease, mainly caused by species from the spotted fever group rickettsiae and is characterized by enlarged lymph nodes following a tick bite. Among cases of TIBOLA, a case of scalp eschar and neck lymphadenopathy after tick bite (SENLAT) is diagnosed when an eschar is present on the scalp, accompanied by peripheral lymphadenopathy (LAP). Only a few cases of SENLAT caused by Bartonella henselae have been reported.

Case Presentation: A 58-year-old male sought medical advice while suffering from high fever and diarrhea. Three weeks before the visit, he had been hunting a water deer, and upon bringing the deer home discovered a tick on his scalp area. Symptoms occurred one week after hunting, and a lump was palpated on the right neck area 6 days after the onset of symptoms. Physical examination upon presentation confirmed an eschar-like lesion on the right scalp area, and cervical palpation revealed that the lymph nodes on the right side were non-painful and enlarged at 2.5 × 1.5 cm. Fine needle aspiration of the enlarged lymph nodes was performed, and results of nested PCR for the Bartonella internal transcribed spacer (ITS) confirmed B. henselae as the causative agent.

Conclusion: With an isolated case of SENLAT and a confirmation of B. henselae in Korea, it is pertinent to raise awareness to physicians in other Asian countries that B. henselae could be a causative agent for SENLAT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12879-020-4940-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7066777PMC
March 2020

Severe Fever with Thrombocytopenia Syndrome Associated with Manual De-Ticking of Domestic Dogs.

Vector Borne Zoonotic Dis 2020 04 11;20(4):285-294. Epub 2020 Feb 11.

Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease. SFTS is caused by the SFTS virus, a novel phlebovirus, and is spread by ticks. A 50-year-old man was admitted to our hospital with the chief complaint of fever and was diagnosed with confirmed SFTS. An epidemiological investigation was conducted, and immunofluorescent antibody assays (IFAs) were performed to determine the role of the patient's three dogs in the transmission. PCR assays were performed using ticks that were collected with the dragging and flagging method from the patient's dogs and home. PCR results were positive, and IFA confirmed an increased antibody titer. Although the reverse transcription PCR results of the three dogs were negative for SFTS virus, one dog had an elevated SFTS IFA immunoglobulin G (IgG) titer of 1:1,024. Moreover, a number of ticks were observed in the area surrounding the dog cages. Based on the findings of the patient interview, the patient was likely to have acquired SFTS by blood splash because he removed or burst ticks from the dogs with his bare hands. Although no tick bites were reported, tick transmission could not be ruled out. Studies have shown that only one in three individuals with a diagnosis of SFTS recalls a tick bite; thus, a definite exclusion of tick transmission in this case was not possible. The epidemiological findings of our case suggest a possible relationship between tick infestation in domestic dogs and SFTS virus transmission to humans. However, there is no direct evidence supporting this viral transmission route. Future studies are needed to further investigate a potential route of SFTS transmission by exposure to engorged tick blood or pet dogs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/vbz.2019.2463DOI Listing
April 2020

Prevalence of Orientia tsutsugamushi, Anaplasma phagocytophilum and Leptospira interrogans in striped field mice in Gwangju, Republic of Korea.

PLoS One 2019 16;14(8):e0215526. Epub 2019 Aug 16.

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

This study investigated the prevalence of Orientia tsutsugamushi, Anaplasma phagocytophilum, and Leptospira interrogans in wild rodents through molecular detection using organ samples and through serological assay using blood samples of mice collected from two distinct sites in Gwangju Metropolitan City, Republic of Korea (ROK). A total of 47 wild rodents, identified as Apodemus agrarius (A. agrarius), were captured from June to August 2016. The seroprevalence of antibodies against bacterial pathogens in A. agrarius sera was analyzed; 17.4% (8/46) were identified as O. tsutsugamushi through indirect immunofluorescence assay and 2.2% (1/46) were identified as Leptospira species through passive hemagglutination assay. Using polymerase chain reaction, the spleen, kidney and blood samples were investigated for the presence of O. tsutsugamushi, A. phagocytophilum, and L. interrogans. Out of the 47 A. agrarius, 19.1% (9/47) were positive for A. phagocytophilum and 6.4% (3/47) were positive for L. interrogans, while none were positive for O. tsutsugamushi. Four out of 46 (8.7%) blood samples, six out of 45 (13.3%) spleen samples, and one out of 47 (2.1%) kidney samples were positive for A. phagocytophilum. Three out of 47 (6.4%) kidney samples were positive for L. interrogans. The sequencing results of PCR positive samples demonstrated > 99% similarity with A. phagocytophilum and L. interrogans sequences. A. phagocytophilum was mostly detected in the spleen, whereas L. interrogans was mostly detected in the kidneys. Notably, A. phagocytophilum and L. interrogans were detected in A. agrarius living in close proximity to humans in the metropolitan suburban areas. The results of this study indicate that rodent-borne bacteria may be present in wild rodents in the metropolitan suburban areas of ROK.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0215526PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6697328PMC
March 2020

Detection of Borrelia miyamotoi in Ixodes nipponensis in Korea.

PLoS One 2019 29;14(7):e0220465. Epub 2019 Jul 29.

Clinical Pathology, Gwangju Health University, Gwangju, South Korea.

Background: This study investigated Borrelia species prevalence in ticks from vegetation, through a molecular method, in Gwangju Metropolitan City, South Korea.

Methodology/principal Findings: A total of 484 ticks were collected through flagging and dragging in a suburban area of Gwangju Metropolitan City, South Korea, in 2014. These ticks were morphologically identified and subjected to nested PCR, targeting Borrelia-specific CTP synthase (pyrG), outer surface protein A (ospA) and flagellin (flaB) genes. Molecular biological species identification of Borrelia-positive ticks was conducted via 16S rRNA PCR assays. Of the 484 ticks collected, 417 (86.2%) were identified as Haemaphysalis longicornis, 42 (8.7%) as H. flava, and 25 (5.2%) as Ixodes nipponensis. All the ixodid ticks containing Borrelia species bacteria were confirmed to be I. nipponensis adults, by both morphological and molecular methods. Of the 25 I. nipponensis ticks collected, four (16%) were positive for Borrelia species, three of which were B. afzelii and one B. miyamotoi.

Conclusions/significance: Our study has shown the harboring of B. miyamotoi by I. nipponensis in South Korea. Morphological and molecular genetic analyses revealed that, in South Korea, I. nipponensis could potentially transmit B. miyamotoi to humans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0220465PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6663023PMC
March 2020

Case Report: Coinfection with and .

Am J Trop Med Hyg 2019 08;101(2):332-335

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.

and are bacteria of the family Rickettsiaceae, which causes fever, rash, and eschar formation; outdoor activities are a risk factor for Rickettsiaceae infection. A 75-year-old woman presented with fever, rash, and eschar and was confirmed as being scrub typhus based on a nested-polymerase chain reaction (N-PCR) test for a 56-kDa gene of ; the genome was identified as the Boryong genotype. In addition, a pan-Rickettsia real-time PCR test was positive and a N-PCR test using a -specific partial outer membrane protein A (rOmpA) confirmed . This is the first case wherein a patient suspected of having scrub typhus owing to the presence of rash and eschar was also found to be coinfected with and based on molecular testing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.18-0631DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6685553PMC
August 2019

Hemorrhagic Fever with Renal Syndrome as a Cause of Acute Diarrhea.

Am J Trop Med Hyg 2019 05;100(5):1236-1239

Department of Bio-Medical Sciences, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Hemorrhagic fever with renal syndrome (HFRS) is a febrile disorder caused in Korea by the Hantaan and Seoul viruses. Its characteristic clinical manifestations include fever, hemorrhage, and renal failure, but a primary presentation with acute infectious diarrhea is rare. Owing to decreased urine output and renal function, a 54-year-old patient was transferred to our hospital from a local clinic, where he had been receiving treatment for diarrhea occurring more than 10 times a day. The patient was treated in the Gastroenterology Department at our hospital for acute renal failure secondary to inflammatory diarrhea based on the findings of stool leukocytes. An immunofluorescent antibody assay showed a 4-fold increase in the acute-phase antibody titer to during recovery. A nested reverse transcription polymerase chain reaction (RT-nPCR) assay of plasma yielded negative results, but Hantaan virus positivity was confirmed on an RT-nPCR assay of the buffy coat. Another 60-year-old patient with watery diarrhea was treated conservatively for suspected infectious diarrhea. However, an immunofluorescent antibody assay showed a 4-fold increase in the acute-phase HFRS antibody titer. RT-nPCR using plasma yielded negative results, but Seoul virus was detected on an RT-nPCR buffy coat assay, confirming the diagnosis of HFRS. Hemorrhagic fever with renal syndrome can present with gastrointestinal symptoms such as acute diarrhea alone. This report highlights the importance of considering HFRS in the differential diagnosis of patients with acute diarrhea and the need for additional research on the usefulness of the buffy coat in the PCR diagnosis of HFRS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.18-0974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6493941PMC
May 2019

Case Report: Scrub Typhus and Q Fever Coinfection.

Am J Trop Med Hyg 2019 05;100(5):1130-1133

Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, South Korea.

A 56-year-old female goat herder had scrub typhus that persisted after receiving doxycycline for 5 days. Her symptoms continued, prompting us to perform further examinations that revealed coinfection of Q fever and scrub typhus via molecular and serological testing. We also isolated using BALB/c mice and L929 cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.18-0092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6493945PMC
May 2019

Indicators of severe prognosis of scrub typhus: prognostic factors of scrub typhus severity.

BMC Infect Dis 2019 Mar 25;19(1):283. Epub 2019 Mar 25.

Department of Internal Medicine, Chosun University College of Medicine, 588 Seosuk-dong, Dong-gu, Gwangju, 501-717, Republic of Korea.

Background: Scrub typhus is an acute disease, characterized by symptoms of fever, which occurs due to infection by Orientia tsutsugamushi. In most cases, patients recover from the disease with appropriate treatment, but serious and fatal complications may occur. The present study examined laboratory findings and tumor necrosis factor-alpha (TNF-α) levels of scrub typhus patients to identify the prognostic predictors of disease severity.

Method: Patients whose scrub typhus diagnosis was confirmed by elevated indirect fluorescent antibody (IFA) levels and positive polymerase chain reaction (PCR) results were classified according to disease severity into one of three groups; i.e., deceased (n = 7), severe (n = 15), and mild (n = 15) retrospectively registered. Additionally, the usefulness of modified Acute Physiology and Chronic Health Evaluation II (APACHE II) score, C-reactive protein (CRP) level, white blood cell (WBC) count, and TNF-α level as prognostic predictors were examined.

Result: The mean TNF-α levels of the deceased, severe, and mild groups were 53.5 (range: 7.8-147.8), 26.0 (1.7-64.4), and 8.8 pg/mL (4.6-16.0), respectively. The results of Kruskal-Wallis tests showed statistically significant differences between the deceased and severe groups versus the mild group (p = 0.005). CRP level and Modified APACHE II score also differed significantly among the groups (p = 0.046 and 0.007, respectively); however, WBC count did not (p = 0.196).

Conclusion: An elevated serum TNF-α level in patients with scrub typhus could predict a severe condition or death and may be useful in predicting patient prognosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12879-019-3903-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6434784PMC
March 2019

Identifying the mechanism underlying treatment failure for Salmonella Paratyphi A infection using next-generation sequencing - a case report.

BMC Infect Dis 2019 Feb 26;19(1):191. Epub 2019 Feb 26.

Department of Premedical Science, College of Medicine, Chosun University, Gwangju, Republic of Korea.

Background: Salmonella is a notorious pathogen that causes gastroenteritis in humans and the emergence of resistance to third-generation cephalosporins and azithromycin have raised concern. There has been rare case of Salmonella Paratyphi A infection accompanied by spondylitis. Here, we report a case of initial antibiotic treatment failure in a Korean man with Salmonella Paratyphi A infection and conducted next-generation sequencing (NGS) to determine the cause of failure of initial treatment for Salmonella Paratyphi A infection.

Case Presentation: A 70-year-old man was admitted to Chosun University Hospital with reported consistent low back pain with a history of having 5 days of chills and fever in another hospital a month ago. He was administered ceftriaxone (2 g daily) for 18 days including initial treatment to cover Salmonella enterica. The antimicrobial susceptibility test using MIC plate, found that the identified organism was resistant to ciprofloxacin and nalidixic acid. Moreover, the Salmonella Paratyphi A isolates were found to have an MIC > 16 mg/L for azithromycin, as he had resistance to both azithromycin and nalidixic acid, the treatment was switched to a combination of ciprofloxacin and cefotaxime. We carried out next-generation sequencing (NGS) to determine the cause of failure of initial treatment for Salmonella Paratyphi A infection. NGS showed that the amino acid substitution GyrA S83F and the expression of multiple RNA-family efflux pumps led to a high-level resistance to quinolone. No genes related to ceftriaxone resistance, such as CTX-M, CMY-2, or other extended-spectrum beta-lactamases were identified in Salmonella enterica Paratyphi A using NGS. The GyrA S83F mutation and the expression of multiple RNA-family efflux pumps may have contributed to the treatment failure of ceftriaxone, even though the MIC of the isolate to ceftriaxone was less than 1.

Conclusion: This case involved a Salmonella Paratyphi A infection accompanied by spondylitis. To our knowledge, this is the first report to elucidate the mechanism underlying antimicrobial resistance using NGS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12879-019-3821-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390365PMC
February 2019
-->