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Dolatyar Dehkharghani A, Haghighat S, Rahnamaye Farzami M, Douraghi M, Rahbar M. Subtyping β-lactamase-producing Escherichia coli strains isolated from patients with UTI by MLVA and PFGE methods. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2021; 24:437-443. [PMID: 34094024 PMCID: PMC8143711 DOI: 10.22038/ijbms.2021.49790.11372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 03/07/2021] [Indexed: 12/03/2022]
Abstract
OBJECTIVES Strain subtyping is an important epidemiological tool to trace contamination, determine clonal relationships between different strains, and the cause of outbreaks. Current subtyping methods, however, yield less than optimal subtype discrimination. Pulsed-field gel electrophoresis is the gold standard method for Escherichia coli and Multiple-Locus Variable-number tandem repeat Analysis is a rapid PCR-based method. The purpose of this study was to evaluate MLVA and PFGE methods for subtyping β -lactamase-producing E. coli strains isolated from urinary tract infections. MATERIALS AND METHODS Overall, 230 E. coli isolates from patients with urinary tract infections were examined for antimicrobial susceptibility testing. 10-loci and 7-loci MLVA and PFGE methods were used for molecular typing of β -lactamase-producing E. coli isolates. RESULTS Out of 230 isolates, 130 (56.5%) β -lactamase-producing E. coli isolates were found in this study. The diversity indices of the VNTR loci showed an average diversity of 0.48 and 0.54 for 7-loci and 10-loci MLVA, respectively. The discriminatory power of PFGE showed a value of 0.87. The discordance between the methods was high. CONCLUSION Our study showed that PFGE is more discriminatory than MVLA. MLVA is a PCR- based method and can generate unmistakable data, in contrast to PFGE. Optimization of polymorphic VNTR is essential to improve the discriminatory power of MLVA based on geographical region.
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Affiliation(s)
- Alireza Dolatyar Dehkharghani
- Department of Microbiology, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Setareh Haghighat
- Department of Microbiology, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Marjan Rahnamaye Farzami
- Department of Microbiology, Research Center of Reference Health Laboratory, Ministry of Health and Medical Education, Tehran, Iran
| | - Masoumeh Douraghi
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Rahbar
- Department of Microbiology, Research Center of Reference Health Laboratory, Ministry of Health and Medical Education, Tehran, Iran
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Lee KH, Yoo JR, Kim YR, Heo ST. Phylogenetic Analysis for the Origin of Typhoid Fever Outbreak on Jeju Island, Korea, in 2017. Infect Chemother 2020; 52:421-426. [PMID: 31997603 PMCID: PMC7533213 DOI: 10.3947/ic.2020.52.3.421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 12/09/2019] [Indexed: 11/24/2022] Open
Abstract
In June 2017, on Jeju Island, six patients were diagnosed with typhoid fever. All six patients were admitted to our hospital with fever, all of them had been working at the same hotel. The gyrA and gyrB genes of four out of six Salmonella typhi cases were amplified by polymerase chain reaction. The phylogenetic tree of the genes showed that the S. Typhi isolates from Jeju Island in 2017 had the same genotype and were similar to isolates from the United Kingdom. The origin of the isolates of the outbreak was the same, and the disease strain may have been imported from outside of Korea.
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Affiliation(s)
- Keun Hwa Lee
- Department of Microbiology and Immunology, Hanyang University College of Medicine, Seoul, Korea
| | - Jeong Rae Yoo
- Division of Infectious Disease, Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea
| | - Young Ree Kim
- Department of Laboratory Medicine, Jeju National University School of Medicine, Jeju, Korea
| | - Sang Taek Heo
- Division of Infectious Disease, Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea
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Wei X, You L, Wang D, Huang H, Li S, Wang D. Antimicrobial resistance and molecular genotyping of Salmonella enterica serovar Enteritidis clinical isolates from Guizhou province of Southwestern China. PLoS One 2019; 14:e0221492. [PMID: 31546249 PMCID: PMC6756847 DOI: 10.1371/journal.pone.0221492] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/07/2019] [Indexed: 11/23/2022] Open
Abstract
Salmonella enterica serovar Enteritidis (S. Enteritidis) is the most common and essential serotype that causes salmonellosis in Guizhou province. This study aimed to investigate the antimicrobial resistance (AMR) and molecular genotyping of 79 S. Enteritidis clinical isolates from 2011 to 2016 in Guizhou, China. Antimicrobial resistance and minimum inhibitory concentrations (MICs) of S. Enteritidis clinical isolates were detected by micro broth dilution method against ten classes 16 antimicrobial agents, and molecular genotyping were examined by pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA). All (100%) isolates showed resistance to at least one antimicrobial. Resistance to nalidixic acid (98.7%) was the highest, followed by sulfamethoxazole (87.3%) and ampicillin (77.2%). The majority of isolates (92.4%) showed decreased susceptibility to ciprofloxacin. Resistance to the third and fourth-generation cephalosporins was observed. Twenty-six AMR profiles were observed, and the predominant AMR profile was ampicillin-streptomycin-sulfamethoxazole-amoxicillin/clavulanic acid-nalidixic acid. A high burden of multidrug resistance (MDR) (81.0%) was found. Seventy-nine S. Enteritidis isolates were divided into 33 different pulsotypes (PTs), and the most frequent PT was PT18. Twenty-six different MLVA types (MTs) were generated with seven VNTR loci analysis of these isolates. The dominant PTs and MTs were persistent during 2011-2016. S. Enteritidis clinical isolates showed higher genetic diversity using PFGE combined with MLVA grouped into 60 PT-MT genotypes. No correlation was observed between genotypes, AMR profiles and geographic location. These data revealed the characteristics of AMR and molecular genotyping of S. Enteritidis clinical isolates in Guizhou province. These results highlight that strengthening the AMR and molecular genotyping surveillance is essential to prevent and control salmonellosis in Guizhou. PFGE combined with MLVA should be powerful tools for the molecular genotyping of S. Enteritidis isolates.
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Affiliation(s)
- Xiaoyu Wei
- Laboratory of Bacterial Infectious Disease of Experimental Center, Guizhou Provincial Center for Disease Control and Prevention, Guiyang, China
| | - Lv You
- Laboratory of Bacterial Infectious Disease of Experimental Center, Guizhou Provincial Center for Disease Control and Prevention, Guiyang, China
| | - Dan Wang
- Institute of Communicable Disease Control and Prevention, Guizhou Provincial Center for Disease Control and Prevention, Guiyang, China
| | - He Huang
- Institute of Communicable Disease Control and Prevention, Guizhou Provincial Center for Disease Control and Prevention, Guiyang, China
| | - Shijun Li
- Laboratory of Bacterial Infectious Disease of Experimental Center, Guizhou Provincial Center for Disease Control and Prevention, Guiyang, China
| | - Dingming Wang
- Institute of Communicable Disease Control and Prevention, Guizhou Provincial Center for Disease Control and Prevention, Guiyang, China
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Kang MS, Oh JY, Kwon YK, Lee DY, Jeong OM, Choi BK, Youn SY, Jeon BW, Lee HJ, Lee HS. Public health significance of major genotypes of Salmonella enterica serovar Enteritidis present in both human and chicken isolates in Korea. Res Vet Sci 2017; 112:125-131. [PMID: 28242576 DOI: 10.1016/j.rvsc.2017.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 02/03/2017] [Accepted: 02/15/2017] [Indexed: 11/17/2022]
Abstract
Salmonella enterica serovar Enteritidis is one of the most common serotypes implicated in Salmonella infections in both humans and poultry worldwide. It has been reported that human salmonellosis is mainly associated with the consumption of poultry products contaminated with serovar Enteritidis. The present study was to extensively analyze the public health risk of serovar Enteritidis isolates from chickens in Korea. A total of 127 chicken isolates were collected from clinical cases, on-farm feces, and chicken meat between 1998 and 2012 and 20 human clinical isolates were obtained from patients with diarrhea between 2000 and 2006 in Korea. To characterize the isolates from chickens and humans, we compared the pulsed-field gel electrophoresis (PFGE) patterns and multilocus variable-number tandem-repeat analysis (MLVA) profiles of the isolates. We further characterized representative isolates of different genotypes using a DNA microarray. PFGE revealed 28 patterns and MLVA identified 16 allelic profiles. The DNA microarray showed high genetic variability in plasmid regions and other fimbrial subunits of the isolates although the virulence gene contents of isolates from the same source and/or of the same genotype were unrelated. PFGE and MLVA showed that major genotypes were present in both human and chicken isolates. This result suggests that chickens in Korea pose a significant risk to public health as a source of serovar Enteritidis as has been noted in other countries.
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Affiliation(s)
- Min-Su Kang
- Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, Republic of Korea.
| | - Jae-Young Oh
- Department of Infectious Diseases & Avian Diseases, College of Veterinary Medicine and Korea Zoonosis Research Institute, Chonbuk National University, Iksan, Republic of Korea
| | - Yong-Kuk Kwon
- Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, Republic of Korea
| | - Deog-Yong Lee
- Division of Enteric Diseases, Center for Infectious Diseases, National Research Institute of Health, Cheongju, Republic of Korea
| | - Ok-Mi Jeong
- Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, Republic of Korea
| | - Byung-Kook Choi
- Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, Republic of Korea
| | - So-Youn Youn
- Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, Republic of Korea
| | - Byung-Woo Jeon
- Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, Republic of Korea
| | - Hye-Jin Lee
- Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, Republic of Korea
| | - Hee-Soo Lee
- Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, Republic of Korea
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Song Q, Shen X, Yang Y, Zhang D, Gao H. Genetically Similar Isolates of Salmonella enterica Serotype Enteritidis Persistent in China for a Long-Term Period. J Food Sci 2016; 81:M1778-81. [PMID: 27228342 DOI: 10.1111/1750-3841.13339] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 04/12/2016] [Indexed: 12/01/2022]
Abstract
Salmonella enterica serotype Enteritidis (S. Enteritidis) is an important causative agent of nontyphoidal salmonellosis in human populations. In this study, we collected 72 S. Enteritidis strains from 2004 to 2014 in Ningbo, mid-east China. Of the 72 strains, we identified a dominant clone of 58 strains recovered from patient's feces (n = 48), blood (n = 1), pleural effusion (n = 1), chickens (n = 3), and dessert cakes (n = 5) by pulsed-field gel electrophoresis (PFGE) and variable-number of tandem repeat analysis (MLVA). The profile arrangements of MLVA were SE1-SE2-SE3-SE5-SE6-SE8-SE9: 4-4-3-11-10-1-3. These dominant strains were susceptible to ampicillin, chloramphenicol, tetracycline, ciprofloxacin, gentamicin, cefotaxime and trimethoprim-sulfamethoxazole, and resistant to nalidixic acid. Additionally, all isolates harboured virulence genes invA, sipA, sopE, and spvB when tested by PCR. Our results reveal that genetically similar S. Enteritidis strains which accounted for several outbreaks as well as blood infection and pleural cavity infection are prevalent in China for a long-term period. This situation calls for further attention in the prevention and control of foodborne disease caused by Salmonella species.
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Affiliation(s)
- Qifa Song
- Dept. of Microbiology, Ningbo Municipal Centre for Disease Control and Prevention, Ningbo, Zhejiang, People's Republic of China
| | - Xuanyi Shen
- Dept. of Microbiology, Ningbo Municipal Centre for Disease Control and Prevention, Ningbo, Zhejiang, People's Republic of China
| | - Yuanbin Yang
- Dept. of Microbiology, Ningbo Municipal Centre for Disease Control and Prevention, Ningbo, Zhejiang, People's Republic of China
| | - Danyang Zhang
- Dept. of Microbiology, Ningbo Municipal Centre for Disease Control and Prevention, Ningbo, Zhejiang, People's Republic of China
| | - Hong Gao
- Dept. of Microbiology, Ningbo Municipal Centre for Disease Control and Prevention, Ningbo, Zhejiang, People's Republic of China
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Liu Y, Shi X, Li Y, Chen Q, Jiang M, Li W, Qiu Y, Lin Y, Jiang Y, Kan B, Sun Q, Hu Q. The evaluation and application of multilocus variable number tandem repeat analysis (MLVA) for the molecular epidemiological study of Salmonella enterica subsp. enterica serovar Enteritidis infection. Ann Clin Microbiol Antimicrob 2016; 15:4. [PMID: 26823185 PMCID: PMC4731957 DOI: 10.1186/s12941-016-0119-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 01/14/2016] [Indexed: 11/10/2022] Open
Abstract
Background Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) is one of the most prevalent Salmonella serotypes that cause gastroenteritis worldwide and the most prevalent serotype causing Salmonella infections in China. A rapid molecular typing method with high throughput and good epidemiological discrimination is urgently needed for detecting the outbreaks and finding the source for effective control of S. Enteritidis infections. Methods In this study, 194 strains which included 47 from six outbreaks that were well-characterized epidemiologically were analyzed with pulse field gel electrophoresis (PFGE) and multilocus variable number tandem repeat analysis (MLVA). Seven VNTR loci published by the US Center for Disease Control and Prevention (CDC) were used to evaluate and develop MLVA scheme for S. Enteritidis molecular subtyping by comparing with PFGE, and then MLVA was applied to the suspected outbreaks detection. All S. Enteritidis isolates were analyzed with MLVA to establish a MLVA database in Shenzhen, Guangdong province, China to facilitate the detection of S. Enteritidis infection clusters. Results There were 33 MLVA types and 29 PFGE patterns among 147 sporadic isolates. These two measures had Simpson indices of 0.7701 and 0.8043, respectively, which did not differ significantly. Epidemiological concordance was evaluated by typing 47 isolates from six epidemiologically well-characterized outbreaks and it did not differ for PFGE and MLVA. We applied the well established MLVA method to detect two S. Enteritidis foodborne outbreaks and find their sources successfully in 2014. A MLVA database of 491 S. Enteritidis strains isolated from 2004 to 2014 was established for the surveillance of clusters in the future. Conclusions MLVA typing of S. Enteritidis would be an effective tool for early warning and epidemiological surveillance of S. Enteritidis infections. Electronic supplementary material The online version of this article (doi:10.1186/s12941-016-0119-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yao Liu
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, 29# Wangjiang Road, Chengdu, 610064, Sichuan, People's Republic of China.
| | - Xiaolu Shi
- Shenzhen Major Infectious Disease Control Key Laboratory, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Yinghui Li
- Shenzhen Major Infectious Disease Control Key Laboratory, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Qiongcheng Chen
- Shenzhen Major Infectious Disease Control Key Laboratory, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Min Jiang
- Shenzhen Major Infectious Disease Control Key Laboratory, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Wanli Li
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, 29# Wangjiang Road, Chengdu, 610064, Sichuan, People's Republic of China.
| | - Yaqun Qiu
- Shenzhen Major Infectious Disease Control Key Laboratory, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Yiman Lin
- Shenzhen Major Infectious Disease Control Key Laboratory, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Yixiang Jiang
- Shenzhen Major Infectious Disease Control Key Laboratory, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Biao Kan
- Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
| | - Qun Sun
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, 29# Wangjiang Road, Chengdu, 610064, Sichuan, People's Republic of China.
| | - Qinghua Hu
- Shenzhen Major Infectious Disease Control Key Laboratory, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, People's Republic of China. .,School of Life Sciences, Shenzhen University, Shenzhen, 518000, Guangdong, People's Republic of China.
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Ktari S, Ksibi B, Gharsallah H, Mnif B, Maalej S, Rhimi F, Hammami A. Molecular epidemiological characteristics ofSalmonella entericaserovars Enteritidis, Typhimurium and Livingstone strains isolated in a Tunisian university hospital. APMIS 2015; 124:194-200. [DOI: 10.1111/apm.12484] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 10/22/2015] [Indexed: 12/01/2022]
Affiliation(s)
- Sonia Ktari
- Laboratory of Microbiology; Faculté de Medecine Sfax; Centre Hospitalier Universitaire Habib Bourguiba; Sfax Tunisia
| | - Boutheina Ksibi
- Laboratory of Microbiology; Faculté de Medecine Sfax; Centre Hospitalier Universitaire Habib Bourguiba; Sfax Tunisia
| | - Houda Gharsallah
- Laboratory of Microbiology; Faculté de Medecine Sfax; Centre Hospitalier Universitaire Habib Bourguiba; Sfax Tunisia
| | - Basma Mnif
- Laboratory of Microbiology; Faculté de Medecine Sfax; Centre Hospitalier Universitaire Habib Bourguiba; Sfax Tunisia
| | - Sonda Maalej
- Laboratory of Microbiology; Faculté de Medecine Sfax; Centre Hospitalier Universitaire Habib Bourguiba; Sfax Tunisia
| | - Fouzia Rhimi
- Laboratory of Microbiology; Faculté de Medecine Sfax; Centre Hospitalier Universitaire Habib Bourguiba; Sfax Tunisia
| | - Adnene Hammami
- Laboratory of Microbiology; Faculté de Medecine Sfax; Centre Hospitalier Universitaire Habib Bourguiba; Sfax Tunisia
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Lee DH, Hyeon JY, Kim J, Kim J, Kim S, Jeon SE, Choi SW, Hong WT, Song CS, Lee SW. Close genetic relationship between Salmonella enterica serovar Enteritidis isolated from patients with diarrhoea and poultry in the Republic of Korea. Clin Microbiol Infect 2015; 21:e68-70. [DOI: 10.1016/j.cmi.2015.05.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 05/28/2015] [Indexed: 10/23/2022]
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Lee KE, Lee DY, Choi HW, Chae SJ, Yun YS, Lee KC, Cho YS, Yang DK. Characterization of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar 4,[5],12:i:- isolates from pigs presenting with diarrhea in Korea. J Vet Med Sci 2015; 77:1511-5. [PMID: 26074410 PMCID: PMC4667674 DOI: 10.1292/jvms.15-0151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Between 2011 and 2012, a total of 896 pig fecal samples were collected from nine
provinces in Korea, and 50 salmonella enterica susp.
enterica serovar Typhimurium (S. Typhimurium) was
isolated. The characteristics of the 50 strains were analyzed, and 4 strains were
identified as Salmonella enterica subsp. enterica
serovar 4,[5],12:i:-. Salmonella 4,[5],12:i:- could not be distinguished
from S. Typhimurium through phage typing, antimicrobial resistance
testing or multiple-locus variable-number tandem repeat analysis (MLVA). However, among
the four Salmonella 4,[5],12:i:- strains, one (KVCC-BA1400078) was
identified as a Salmonella 4,[5],12:i:- clone isolated from humans in the
United States, and another (KVCC-BA1400080) was identified as DT193, which has been
primarily isolated from humans and animals in European countries. The presence of
Salmonella 4,[5],12:i:- in Korea poses a significant threat of
horizontal transfer between pigs and humans.
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Affiliation(s)
- Ki-Eun Lee
- Animal and Plant Quarantine Agency, Anyang 430-757, Republic of Korea
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Kim SP, Park SO, Lee SJ, Nam SH, Friedman M. A Polysaccharide isolated from the liquid culture of Lentinus edodes (Shiitake) mushroom mycelia containing black rice bran protects mice against salmonellosis through upregulation of the Th1 immune reaction. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:2384-91. [PMID: 24593132 DOI: 10.1021/jf405223q] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The present study investigated the antibacterial effect of a bioprocessed polysaccharide (BPP) isolated from Lentinus edodes liquid mycelial culture supplemented with black rice bran against murine salmonellosis. BPP was not bactericidal in vitro, it did, however, stimulate uptake of the bacteria into RAW 264.7 murine macrophage cells, as indicated by increased colony-forming unit (CFU) counts of the contents of the lysed macrophages incubated with Salmonella Typhimurium for 30 and 60 min. Two hours postinfection, the bacterial counts drastically increased in the macrophages, but 4 and 8 h postinfection BPP extract-treated cells showed lower bacterial counts than the vehicle (saline phosphate pH 7.4 buffer, PBS)-treated control. BPP elicited altered morphology and markedly elevated inducible nitric oxide (NO) synthase (iNOS) mRNA and protein expression in the infected macrophage cells. BPP also activated leukocytes in S. Typhimurium-infected mice, as determined by spleen lymphocyte proliferation and IFN-γ levels in mice sera. ELISA analysis on cytokine production by Th1 and Th2 immune cells from splenocytes of infected mice showed significant increases in the levels of the following Th1 cytokines: IL-1β, IL-2, IL-6, and IL-12. Histology assays of the livers of mice infected with a sublethal dose (1 × 10(4) CFU) of S. Typhimurium showed that BPP, administered daily through an intraperitoneal (ip) or oral route, protected against necrosis of the liver, a biomarker of in vivo salmonellosis. The lifespan of mice similarly infected with a lethal dose of S. Typhimurium (1 × 10(5) CFU) was significantly extended by ip injection or oral administration of the BPP without side effects. These results suggest that the activity of BPP against bacterial infection in mice occurs mainly through the activation of macrophage-mediated immune response resulting from augmented Th1 immunity. The significance of the results for microbial food safety and human health and further research needs are discussed.
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Affiliation(s)
- Sung Phil Kim
- Department of Biological Science, Ajou University , Suwon 443-749, Republic of Korea
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