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Fulltext Investigation of stx 2 + eae + Escherichia coli O157:H7 in beef imported from Malaysia to Thailand

International Food Research Journal, 2011;18(1):381-386.
MyJurnal

To gain insight into the microbiological safety of food products routinely traded across international borders in Southeast Asian countries, beef imported from Malaysia to southern Thailand was examined for contamination with Escherichia coli O157 and its subsequent spread into the imported areas. We screened 31 samples exported from Malaysia and 36 domestic Thai samples. Isolation methods including an O157 antigen-targeted immunomagnetic separation technique, screening on CHROMagar O157 medium, and serotype confirmation of E. coli isolates by specific agglutination tests were employed. Fourteen strains of E. coli O157:H7 were isolated from eight Malaysian samples (25.8%) and six strains from four Thai samples (11.1%). These strains were of the stx1-stx2+eae+ genotype except one Malaysian strain which was of the stx1- stx2- eae+ genotype. All 19 O157:H7 strains possessing the stx2 gene produced little or no Stx2 (reversed passive latex agglutination titer ≤ 4). Of the 19 strains, five Malaysian (38.5%) and two Thai (33.3%) strains exhibited resistance to a set of antibiotics. Finally, the results of two DNA fingerprinting
analyses (O157 IS-printing targeted to IS629 and pulsed-field gel electrophoresis, PFGE) of the O157:H7 strains possessing the stx2 gene, indicated that the Malaysian and Thai strains are closely related. Therefore, E. coli O157:H7 might be transferred from Malaysia to southern Thailand through beef trade.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Fulltext Occurrence of virulent multidrug-resistant Enterococcus faecalis and Enterococcus faecium in the pigs, farmers and farm environments in Malaysia

Tan SC, Chong CW, Teh CSJ, Ooi PT, Thong KL

PeerJ, 2018;6:e5353.
PMID: 30123701 DOI: 10.7717/peerj.5353

Background: Enterococcus faecalis and Enterococcus faecium are ubiquitous opportunistic pathogens found in the guts of humans and farmed animals. This study aimed to determine the occurrence, antimicrobial resistance, virulence, biofilm-forming ability and genotypes of E. faecalis and E. faecium from swine farms. Correlations between the genotypes, virulotypes, antibiotic resistance, and the environmental factors such as locality of farms and farm hygiene practice were explored.
Methods: E. faecalis and E. faecium strains were isolated from the oral, rectal and fecal samples of 140 pigs; nasal, urine and fecal samples of 34 farmers working in the farms and 42 environmental samples collected from seven swine farms located in Peninsular Malaysia. Antibiotic susceptibility test was performed using the disk diffusion method, and the antibiotic resistance and virulence genes were detected by Polymerase Chain Reaction. Repetitive Extragenic Palindromic-Polymerase Chain Reaction and Pulsed-Field Gel Electrophoresis were performed to determine the clonality of the strains. Crosstab/Chi-square test and DistLM statistical analyses methods were used to determine the correlations between the genotypes, virulence factors, antibiotic resistance, and the environmental factors.
Results: A total of 211 E. faecalis and 42 E. faecium were recovered from 140 pigs, 34 farmers and 42 environmental samples collected from seven swine farms in Peninsular Malaysia. Ninety-eight percent of the strains were multidrug-resistant (resistant to chloramphenicol, tetracycline, ciprofloxacin and erythromycin). Fifty-two percent of the strains formed biofilms. Virulence genes efa, asaI, gelE, esp, cyl and ace genes were detected. Virulence genes efa and asaI were most prevalent in E. faecalis (90%) and E. faecium (43%), respectively. Cluster analyses based on REP-PCR and PFGE showed the strains were genetically diverse. Overall, the strains isolated from pigs and farmers were distinct, except for three highly similar strains found in pigs and farmers. The strains were regional- and host-specific.
Discussion: This study revealed alarming high frequencies of multidrug-resistant enterococci in pigs and swine farmers. The presence of resistance and virulence genes and the ability to form biofilm further enhance the persistence and pathogenicity of the strains. Although the overall clonality of the strains were regionals and host-specific, strains with high similarity were found in different hosts. This study reiterates a need of a more stringent regulation to ensure the proper use of antibiotics in swine husbandry to reduce the wide spread of multidrug-resistant strains.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Genetic relatedness, antimicrobial resistance and biofilm formation of Salmonella isolated from naturally contaminated poultry and their processing environment in northern Malaysia

Chuah LO, Shamila Syuhada AK, Mohamad Suhaimi I, Farah Hanim T, Rusul G

Food Res Int, 2018 03;105:743-751.
PMID: 29433269 DOI: 10.1016/j.foodres.2017.11.066

We investigated the genetic relatedness, antibiotic resistance and biofilm-producing ability of 114 strains of Salmonella, belonged to three serotypes (Corvallis, Brancaster and Albany), isolated from naturally contaminated poultry and their environment in wet markets and smale-scale processing plant from northern Malaysia. Pulsed-field gel electrophoresis revealed that Salmonella strains isolated from various wet markets were clonally related, suggesting the widespread dissemination of these three serotypes in northern Malaysia. All except one strain of Salmonella were resistant to more than two classes of antibiotics, hence regarded as multidrug resistant (MDR). Resistance to sulphonamide (96.5%), ampicillin (89.5%), tetracycline (85.1%), chloramphenicol (75.4%), trimethoprim (68.4%), trimethoprim-sulfamethoxazole (67.5%), streptomycin (58.8%) and nalidixic acid (44.4%) were observed. Resistance determinants, floR, cmlA, tetA, tetB, tetG, temB, blaPSE-1, sul1, sul2, qnrA, qnrS, strA and aadA were detected by PCR among MDR Salmonella strains. Seventy-six strains (66.7%) harboured class-I integrons. The gene cassettes identified were dfrA1, dfrA12, aadA2 and an open reading frame orfC with unknown function. All Salmonella strains produced biofilm and 69.3% of them were strong biofilm-producers. Our findings suggested that most likely, persistent Salmonella colonises various sites in the processing environment by producing biofilm, which leads to their widespread dissemination in wet markets located in northern Malaysia.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Fulltext Data on antibiogram and resistance genes harboured bySalmonellastrains and their Pulsed-field gel electrophoresis clusters

Chuah LO, Shamila Syuhada AK, Mohamad Suhaimi I, Farah Hanim T, Rusul G

Data Brief, 2018 Apr;17:698-702.
PMID: 29511712 DOI: 10.1016/j.dib.2018.01.098

This article describes the Pulsed-field gel electrophoresis clustering of the predominantSalmonellastrains (Salmonellaser. Albany,Salmonellaser. Brancaster, andSalmonellaser. Corvallis) isolated from poultry and processing environment in wet market and small-scale processing plant in Penang and Perlis, the northern states of Malaysia. Agar disk diffusion assay was performed to determine the phenotypic antibiotic resistance of theseSalmonellastrains. The most common antibiograms among the three predominantSalmonellaserovars were reported. The presence of integrase genes and antibiotic resistance genes conferring to resistance against β-lactams, aminoglycosides, tetracyclines, quinolones, sulphonamides and chloramphenicol, was detected via PCR amplification.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Fulltext Using pulsed-field gel electrophoresis in the molecular investigation of an outbreak of Serratia marcescens infection in an intensive care unit

Alfizah H, Nordiah AJ, Rozaidi WS

Singapore Med J, 2004 May;45(5):214-8.
PMID: 15143356

Serratia marcescens is a well-known cause of nosocomial infections and outbreaks, particularly in immunocompromised patients with severe underlying disease. An outbreak due to S. marcescens infection was detected from 13 to 22 February 2001 at the intensive care unit (ICU) of our institution. We used pulsed-field gel electrophoresis (PFGE) typing to analyse the outbreak strains involved.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Characterization of Nontyphoidal Salmonella Isolates from Asymptomatic Migrant Food Handlers in Peninsular Malaysia

Woh PY, Thong KL, Behnke JM, Lewis JW, Zain SNM

J Food Prot, 2017 Aug;80(8):1378-1383.
PMID: 28722485 DOI: 10.4315/0362-028X.JFP-16-342

Asymptomatic Salmonella carriers who work as food handlers pose food safety and public health risks, particularly during food preparation, and this has serious implications for the disease burden in society. Therefore, we conducted a study to determine the number of Salmonella carriers in a migrant cohort in several food establishments in three major cities in Peninsular Malaysia. Sociodemographic data and stool samples were collected and analyzed using standard methods of detection and isolation. Antimicrobial susceptibility tests of the positive samples were also performed. A total of 317 migrant food handlers, originating from South and Southeast Asian countries, were recruited voluntarily. Nine (2.8%) stool samples were confirmed to be Salmonella positive. PCR serotyping and pulsed-field gel electrophoresis identified four serotypes as Typhimurium (n = 3), Corvallis (n = 2), Hadar (n = 1), Agona (n = 1) and two unknown serovars. Antimicrobial susceptibility tests revealed that all nine isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, ceftazidime, ceftriaxone, and gentamycin. However, seven isolates were found to be multidrug resistant to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, sulfonamides, streptomycin, and tetracycline. This study highlights that carriers of nontyphoidal Salmonella exist among migrant food handlers, which poses a health risk to consumers through food contamination. Our results indicate a need for authorities to enhance food safety awareness in the migrant workers and to reevaluate current health screening methods to include preventive measure such as mandatory stool screening as part of the preemployment and routine health examinations.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Fulltext Clonal distribution and possible microevolution of methicillin-resistant Staphylococcus aureus strains in a teaching hospital in Malaysia

Tan XE, Neoh HM, Hussin S, Zin NM

Asian Pac J Trop Biomed, 2013 Mar;3(3):224-8.
PMID: 23620843 DOI: 10.1016/S2221-1691(13)60055-6

OBJECTIVE: To genotypically characterize methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from medical and surgical wards in Universiti Kebangsaan Malaysia Medical Centre (UKMMC) in 2009.
METHODS: MRSA strains were collected and molecularly typed by pulsed-field gel electrophoresis (PFGE).
RESULTS: PFGE typing on 180 MRSA isolated in UKMMC identified 5 pulsotypes (A-E) and 6 singletons, where pulsotypes B and C were suspected to be divergent clones originating from a single ancestor. This study also showed that most MRSA strains were isolated from swab (119 isolates), followed by blood (22 isolates), tracheal aspirate (11 isolates) and sputum (10 isolates). On the other hand, urine and bone isolates were less, which were 4 and 1 isolates, respectively. The distribution of different pulsotypes of MRSA among wards suggested that MRSA was communicated in surgical and medical wards in UKMMC, with pulsotype B MRSA as the dominant strain. Besides, it was found that most deceased patients were infected by pulsotype B MRSA, however, no particular pulsotype could be associated with patient age, underlying disease, or ward of admittance.
CONCLUSIONS: Five pulsotypes of MRSA and 6 singletons were identified, with pulsotype B MRSA as the endemic strains circulating in these wards, which is useful in establishment of preventive measures against MRSA transmission.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Combined use of ribotyping, PFGE typing and IS431 typing in the discrimination of nosocomial strains of methicillin-resistant Staphylococcus aureus

Yoshida T, Kondo N, Hanifah YA, Hiramatsu K

Microbiol. Immunol., 1997;41(9):687-95.
PMID: 9343819

We have previously reported the phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clinical strains isolated in Malaya University Hospital in the period 1987 to 1989 using antibiogram, coagulase typing, plasmid profiles, and phage typing. Here, we report the analysis of the same strains with three genotyping methods; ribotyping, pulsed-field gel electrophoresis (PFGE) typing, and IS431 typing (a restriction enzyme fragment length polymorphism analysis using an IS431 probe). Ribotyping could discriminate 46 clinical MRSA strains into 5 ribotypes, PFGE typing into 22 types, and IS431 typing into 15 types. Since the differences of the three genotyping patterns from strain to strain were quite independent from one another, the combined use of the three genotyping methods could discriminate 46 strains into 39 genotypes. Thus, the powerful discriminatory ability of the combination was demonstrated.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field*
Macrorestriction analysis and antimicrobial susceptibility profiling of Salmonella enterica at a University Teaching Hospital, Kuala Lumpur

Tiong V, Thong KL, Yusof MY, Hanifah YA, Sam JI, Hassan H

Jpn J Infect Dis, 2010 Sep;63(5):317-22.
PMID: 20858996

The genetic diversity and antimicrobial resistance rates of clinical Salmonella isolates (2007-2008) at the University of Malaya Medical Centre, Kuala Lumpur, were investigated and the genetic diversity of the isolates was determined by pulsed-field gel electrophoresis (PFGE) and repetitive extragenic palindromic (REP)-PCR. XbaI-PFGE analysis generated 57 profiles (Dice coefficient, F=0.08-1.00), whereas REP-PCR using the REP primer generated only 35 (F=0.34-1.00). PFGE was therefore the more discriminative and reproducible method for assessing the genetic diversity of salmonellae. The antibiograms of 78 Salmonella isolates were assessed against 19 antimicrobials using the disk diffusion method. Twenty serotypes were identified, with the most common being S. Enteritidis (18%) followed by S. Typhimurium (14%), S. Paratyphi B var Java (9%), S. Weltevreden (9%), and S. Corvallis (9%). A total of 38 resistant profiles were defined, with 53.8% of the isolates being resistant to three or more antimicrobials. The highest resistance rates were observed for cephalothin (55.1%), tetracycline (47.4%), and nalidixic acid (35.9%). The presence of multidrug-resistant Salmonella strains is a cause for concern as it may limit the treatment of severe salmonellosis. One multidrug-resistant S. Enteritidis strain was a putative extended-spectrum beta-lactamase producer, based on a double disk diffusion analysis, and was resistant to ceftriaxone (MIC>32 microg/mL). The data generated by this study will contribute towards epidemiological monitoring and investigations of Salmonella infections in Malaysia.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field/methods
Intestinal carriage of multidrug-resistant gram-negative bacteria in preterm-infants during hospitalization in neonatal intensive care unit (NICU)

Yap PS, Ahmad Kamar A, Chong CW, Yap IK, Thong KL, Choo YM, et al.

Pathog Glob Health, 2016 Sep;110(6):238-246.
PMID: 27650884

The prevalence and antibiotic susceptibility of intestinal carriage of Gram-negative bacteria among preterm infants admitted to the neonatal intensive care unit (NICU) in a tertiary teaching hospital in Malaysia were determined. A total of 34 stool specimens were obtained from preterm infants upon admission and once weekly up to two weeks during hospitalization. The presumptive colonies of Escherichia coli and Klebsiella pneumoniae were selected for identification, antibiotic susceptibility testing, and subtyping by using pulsed-field gel electrophoresis (PFGE). Out of 76 Gram-negative isolates, highest resistance was detected for amoxicillin/clavulanate (30.8%, n = 16), ceftriaxone (42.3%, n = 22), ceftazidime (28.8%, n = 15), cefoxitin (28.8%, n = 15), aztreonam (36.5%, n = 19), and polymyxin B (23.1%, n = 12). Three colistin resistant K. pneumoniae have also been detected based on E-test analysis. Thirty-nine isolates of K. pneumoniae and 20 isolates of E. coli were resistant to more than three antimicrobial classes and were categorized as multidrug resistant (MDR). PFGE analysis revealed a higher diversity in pulsotypes for K. pneumoniae (18 pulsotypes) in comparison to E. coli (four pulsotypes). In addition, a total of fifteen pulsotypes was observed from 39 MDR K. pneumoniae. The risk factors for antibiotic resistance were assessed using random forest analysis. Gender was found to be the most important predictor for colistin resistant while length, OFC, and delivery mode were showing greater predictive power in the polymyxin B resistance. This study revealed worrying prevalence rates of intestinal carriage of multidrug-resistant K. pneumoniae and E. coli of hospitalized preterm infants in Malaysia, particularly high resistance to polymyxins.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field/methods
Fulltext First report on the molecular epidemiology of Malaysian Staphylococcus epidermidis isolated from a university teaching hospital

Sani NA, Sapri HF, Neoh HM, Hussin S

BMC Res Notes, 2014;7:597.
PMID: 25186825 DOI: 10.1186/1756-0500-7-597

Staphylococcus epidermidis is a pathogen associated with nosocomial infections whose medical importance has increased due to progressively invasive medical procedures. In this study, we characterized the molecular epidemiology of S. epidermidis strains circulating in our university hospital situated in Kuala Lumpur, Malaysia.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Genotypic characterization of Streptococcus pneumoniae serotype 19F in Malaysia

Jeevajothi Nathan J, Mohd Desa MN, Thong KL, Clarke SC, Masri SN, Md Yasin R, et al.

Infect Genet Evol, 2014 Jan;21:391-4.
PMID: 24342879 DOI: 10.1016/j.meegid.2013.11.026

Streptococcus pneumoniae is an epidemiologically important bacterial pathogen. Recently, we reported the antibiotic susceptibility patterns of a limited collection of pneumococcal isolates in Malaysia with a high prevalence of erythromycin resistant strains. In the present study, 55 of the pneumococcal isolates of serotype 19F were further analysed by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The generated genotypic patterns were then correlated with the antibiograms previously reported. Forty-seven different PFGE profiles (PTs) were obtained, showing that the isolates were genetically diverse. MLST identified 16 sequence types (STs) with ST-236 being predominant (58.2%), followed by ST-81 (10.3%). Among the ST-236 isolates, 22 were erythromycin resistant S. pneumoniae (ERSP) and 15 were trimethoprim/sulfamethoxazole (TMP/SMX) resistant, while among ST-81, four isolates were ERSP and two were TMP/SMX resistant. The high prevalence of erythromycin resistant serotype 19F isolates of ST-236 in this study has also been reported in other North and South East Asian countries.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Molecular characterization showed limited genetic diversity among Salmonella Enteritidis isolated from humans and animals in Malaysia

Ngoi ST, Thong KL

Diagn Microbiol Infect Dis, 2013 Dec;77(4):304-11.
PMID: 24139970 DOI: 10.1016/j.diagmicrobio.2013.09.004

Salmonella enterica serovar Enteritidis (S. Enteritidis) is the most common causative agent of non-typhoidal salmonellosis in Malaysia. We aimed to characterize S. Enteritidis isolated from humans and animals by analyzing their antimicrobial resistance profiles and genotypes. A total of 111 strains were characterized using multiple-locus variable-number tandem repeat analysis, pulsed-field gel electrophoresis, and antimicrobial susceptibility testing. Both typing methods revealed that genetically similar S. Enteritidis strains had persisted among human and animal populations within the period of study (2003-2008). Only 39% of the strains were multi-drug resistant (i.e., resistant to 3 or more classes of antimicrobial agents), with a majority (73%) of these in low-risk phase (multiple antibiotic resistant index <0.20). Limited genetic diversity among clinical and zoonotic S. Enteritidis suggested that animals are possible sources of human salmonellosis. The degree of multi-drug resistance among the strains was generally low during the study period.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Fulltext The significance of coagulase-negative staphylococci bacteremia in a low resource setting

Abdul Rahman Z, Hamzah SH, Hassan SA, Osman S, Md Noor SS

J Infect Dev Ctries, 2013 Jun;7(6):448-52.
PMID: 23771288 DOI: 10.3855/jidc.2535

INTRODUCTION: Coagulase-negative staphylococci (CoNS) are a group of micro-organisms that are increasingly implicated as a cause of significant infection and the leading cause of bloodstream infection (BSI). One important predictor of true BSI is the isolation of CoNS from multiple blood cultures, presuming that the isolates represent the same species. Thus the objective of this study was to determine the significance of repeated CoNS isolated from blood cultures.
METHODOLOGY: This was a prospective laboratory study which was initiated in June 2007 and lasted until July 2008. CoNS isolates were obtained from patients who had two positive blood cultures within a 14-day interval. CoNS were identified to the species level using an API-Staph, and antibiotics susceptibility testing was performed according to Clinical and Laboratory Standards Institute specifications. Strain relatedness was confirmed using pulsed-field gel electrophoresis.
RESULTS: During the study period, 202 CoNS-positive samples were isolated from 101 patients. The most common species isolated was Staphylococcus epidermidis (59.0%), and 83.2% of the patients isolated the same species of CoNS from repeated blood cultures. Among the isolates of the same species, only 40.7% had the same antibiogram. CoNS with the same species and antibiogram had 93.3% probability of belonging to the same strain. Most (65.5%) of the patients were treated with antibiotics, primarily from the glycopeptides group.
CONCLUSION: Speciation and antibiogram of CoNS from repeated blood cultures are adequate in determining the significance of repeated CoNS isolated from blood cultures.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Antimicrobial susceptibility and pulsed: field Gel Electrophoretic analysis of Salmonella in a tertiary hospital in northern Malaysia

Thong KL, Lai WL, Dhanoa A

J Infect Public Health, 2011 Jun;4(2):65-72.
PMID: 21663875 DOI: 10.1016/j.jiph.2011.03.003

Salmonella infections remain a major public health problem in developing countries. The occurrence of infections caused by antimicrobial-resistant Salmonella has been on the rise complicating the available therapeutic options. The study aimed to determine the antibiograms and genotypes of prevalent Salmonella serotypes.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Fulltext Isolation and molecular characterization of Leptospira interrogans and Leptospira borgpetersenii isolates from the urban rat populations of Kuala Lumpur, Malaysia

Benacer D, Mohd Zain SN, Amran F, Galloway RL, Thong KL

Am J Trop Med Hyg, 2013 Apr;88(4):704-9.
PMID: 23358635 DOI: 10.4269/ajtmh.12-0662

Rats are considered the principal maintenance hosts of Leptospira. The objectives of this study were isolation and identification of Leptospira serovars circulating among urban rat populations in Kuala Lumpur. Three hundred urban rats (73% Rattus rattus and 27% R. norvegicus) from three different sites were trapped. Twenty cultures were positive for Leptospira using dark-field microscopy. R. rattus was the dominant carrier (70%). Polymerase chain reaction (PCR) confirmed that all isolates were pathogenic Leptospira species. Two Leptospira serogroups, Javanica and Bataviae, were identified using microscopic agglutination test (MAT). Pulsed-field gel electrophoresis (PFGE) identified two serovars in the urban rat populations: L. borgpetersenii serovar Javanica (85%) and L. interrogans serovar Bataviae (15%). We conclude that these two serovars are the major serovars circulating among the urban rat populations in Kuala Lumpur. Despite the low infection rate reported, the high pathogenicity of these serovars raises concern of public health risks caused by rodent transmission of leptospirosis.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Characterization of vibrio parahaemolyticus isolated from coastal seawater in peninsular Malaysia

Tanil GB, Radu S, Nishibuchi M, Rahim RA, Napis S, Maurice L, et al.

Southeast Asian J. Trop. Med. Public Health, 2005 Jul;36(4):940-5.
PMID: 16295549

Twenty-one Vibrio parahaemolyticus isolates representing 21 samples of coastal seawater from three beaches in peninsular Malaysia were found to be sensitive to streptomycin, norfloxacin and chloramphenicol. Resistance was observed to penicillin (100%), ampicillin (95.2%), carbenicilin (95.2%), erythromycin (95.2%), bacitracin (71.4%), cephalothin (28.6%), moxalactam (28.6%), kanamycin (19.1%), tetracycline (14.3%), nalidixic acid (9.5%) and gentamicin (9.5%). Plasmids of 2.6 to 35.8 mDa were detected among plasmid-containing isolates. All isolates carried the Vp-toxR gene specific to V. parahaemolyticus and were negative for the tdh gene, but only one isolate was positive for the trh gene. DNA fingerprinting of the isolates using ERIC-PCR and PFGE showed that the isolates belong to two major clonal groups, with several isolates from different locations in the same group, indicating the presence of similar strains in the different locations.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Fulltext The dnd operon for DNA phosphorothioation modification system in Escherichia coli is located in diverse genomic islands

Ho WS, Ou HY, Yeo CC, Thong KL

BMC Genomics, 2015;16:199.
PMID: 25879448 DOI: 10.1186/s12864-015-1421-8

Strains of Escherichia coli that are non-typeable by pulsed-field gel electrophoresis (PFGE) due to in-gel degradation can influence their molecular epidemiological data. The DNA degradation phenotype (Dnd(+)) is mediated by the dnd operon that encode enzymes catalyzing the phosphorothioation of DNA, rendering the modified DNA susceptible to oxidative cleavage during a PFGE run. In this study, a PCR assay was developed to detect the presence of the dnd operon in Dnd(+) E. coli strains and to improve their typeability. Investigations into the genetic environments of the dnd operon in various E. coli strains led to the discovery that the dnd operon is harboured in various diverse genomic islands.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
Lactobacillus durianis sp. nov., isolated from an acid-fermented condiment (tempoyak) in Malaysia

Leisner JJ, Vancanneyt M, Lefebvre K, Vandemeulebroecke K, Hoste B, Vilalta NE, et al.

Int J Syst Evol Microbiol, 2002 May;52(Pt 3):927-931.
PMID: 12054259 DOI: 10.1099/00207713-52-3-927

Lactic acid bacteria (LAB) are the predominant micro-organisms in tempoyak, a Malaysian acid-fermented condiment. In a study on the diversity of LAB in this product, three isolates could not be identified using SDS-PAGE of whole-cell proteins or API 50 CH. The taxonomic position of the three isolates was clarified in the present study. 16S rDNA sequencing classified a representative strain in the genus Lactobacillus, clearly separated from all known species, and most closely related to the Lactobacillus reuteri phylogenetic group. DNA-DNA hybridization experiments and an extensive phenotypic description confirm that the strains represent a single and separate novel species among the obligately heterofermentative lactobacilli. The three isolates are distinguished at the intra-species level by plasmid profiling, pulsed-field gel electrophoresis of macro-restriction fragments and biochemical features. The name Lactobacillus durianis sp. nov. is proposed for the novel taxon and the type strain is LMG 19193T (= CCUG 45405T).

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field
A major methicillin-resistant Staphylococcus aureus clone predominates in Malaysian hospitals

Norazah A, Lim VK, Rohani MY, Alfizah H, Koh YT, Kamel AG

Epidemiol Infect, 2003 Jun;130(3):407-11.
PMID: 12825724

This study was conducted to determine the molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Malaysian hospitals. A total of 264 MRSA isolates from eight hospitals were subjected to typing by pulsed-field gel electrophoresis (PFGE) of SmaI restricted DNA. Antibiotic disk susceptibility testing was also carried out to determine their resistance patterns. Thirty-one PFGE pattern types were identified. Three major pattern types A, ZC and K were found with type A the predominant profile in c. 80% of strains and present in all hospitals. Unlike type A, other DNA pattern types were unique to the hospitals in which they were isolated. PFGE type A also consisted of strains that were multiply antibiotic resistant. The presence of a single predominant PFGE type in Malaysian hospitals is an important finding which suggests that inter-hospital spread of MRSA had occurred frequently and regularly.

Matched MeSH terms: Electrophoresis, Gel, Pulsed-Field

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