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  1. rRNA gene restriction patterns of Leptospira: a molecular typing system
    Pérolat P, Grimont F, Regnault B, Grimont PA, Fournié E, Thevenet H, et al.
    Res. Microbiol., 1990 Feb;141(2):159-71.
    PMID: 2189169
    A total of 67 serovar reference strains and 7 isolates belonging to the genus Leptospira were characterized by ribosomal ribonucleic acid (rRNA) gene restriction patterns. Fifty patterns were observed. Strains belonging to different genomic species always gave different patterns. However, genomic species were subdivided into several patterns. Forty-three serovars gave a specific pattern. Some serovars could not be separated by rRNA gene restriction patterns: strains of serovars icterohaemorrhagiae, copenhageni, lai, pyrogenes and jalna gave pattern 1; serovars birkini, mankarso and wolffi gave pattern 4; serovars canicola, gem, hebdomadis, pomona and hardjo (strain hardjoprajitno) gave pattern 12; serovars valbuzzi and zanoni gave pattern 14; serovars jonsis, malaya and sumneri gave pattern 16; serovars arborea, ballum, castellonis and kenya gave pattern 35; and serovars borincana and shermani gave pattern 43. These data provide the bases for a molecular typing system for the genus Leptospira.
    Matched MeSH terms: Bacterial Typing Techniques*
  2. Randomly amplified polymorphic DNA typing: a useful tool for rapid epidemiological typing of Klebsiella pneumoniae
    Wong NA, Linton CJ, Jalal H, Millar MR
    Epidemiol Infect, 1994 Dec;113(3):445-54.
    PMID: 7995354
    Discriminatory typing methods are invaluable in the investigation of outbreaks of infectious diseases. Single primers were used to generate randomly amplified polymorphic DNA (RAPD) profiles from Klebsiella pneumoniae isolates of various serotype and K. pneumoniae isolates from cases of sepsis at a Malaysian hospital and two English hospitals. RAPD profiles of acceptable reproducibility, a maximum of three minor band variations, were produced using a rapid DNA extraction method. RAPD typing of K. pneumoniae was shown to be as discriminatory as restriction fragment length polymorphism analysis using pulsed field gel electrophoresis yet quicker and less costly. The findings suggest that RAPD typing may be a useful tool for the epidemiological typing of K. pneumoniae.
    Matched MeSH terms: Bacterial Typing Techniques*
  3. Molecular epidemiologic analysis of Vibrio cholerae O1 isolates by pulsed-field gel electrophoresis
    Mahalingam S, Cheong YM, Kan S, Yassin RM, Vadivelu J, Pang T
    J Clin Microbiol, 1994 Dec;32(12):2975-9.
    PMID: 7883885
    Isolates of Vibrio cholerae O1 El Tor from two well-defined cholera outbreaks in Malaysia were analyzed by using pulsed-field gel electrophoresis (PFGE). Isolates from sporadic cases occurring during the same time period were also studied. Digestion of chromosomal DNA from these isolates of V. cholerae O1 with restriction endonucleases NotI (5'-GCGGCCGC-3') and SfiI (5'-GGCCNNNN-3'), followed by PFGE, produced restriction endonuclease analysis (REA) patterns consisting of 13 to 24 bands (ranging in size from 46 to 398 kbp). Analysis of the REA patterns generated by PFGE after digestion with NotI and SfiI suggested the clonal nature and close genetic identity of the isolates obtained during each of the two outbreaks (Dice coefficient, 0.93 to 1.0). Although they had very similar REA patterns, the two outbreak clones were not identical. Isolates of V. cholerae O1 from sporadic cases, on the other hand, appeared to be much more heterogeneous (five different REA patterns detected in the five isolates tested; Dice coefficient, 0.31 to 0.81) than those obtained during the two outbreaks. We conclude that PFGE of V. cholerae O1 chromosomal DNA digested with infrequently cutting restriction endonucleases is a useful method for molecular typing of V. cholerae isolates for epidemiological purposes.
    Matched MeSH terms: Bacterial Typing Techniques*
  4. Molecular analysis of Salmonella enteritidis by pulsed-field gel electrophoresis and ribotyping
    Thong KL, Ngeow YF, Altwegg M, Navaratnam P, Pang T
    J Clin Microbiol, 1995 May;33(5):1070-4.
    PMID: 7615707
    A total of 61 isolates of Salmonella enteritidis were analyzed by the techniques of pulsed-field gel electrophoresis (PFGE) and ribotyping. Twenty-three of the isolates were from Zurich, Switzerland, and 38 isolates were from the University Hospital, Kuala Lumpur, Malaysia. Five of the Malaysian isolates were hospital-related outbreak strains and were shown to be indistinguishable by PFGE analysis following digestion with three different restriction endonucleases, XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3'). The PFGE pattern of an isolate from a suspected carrier staff nurse was found to be identical to those of the hospital outbreak isolates. These isolates were also indistinguishable by ribotyping with SmaI and SphI. The same single PFGE pattern was also detected in 29 of 32 sporadic isolates of S. enteritidis. Four closely related ribotypes were detected among these 29 isolates. Similarly, outbreak-related strains from Switzerland showed close genetic identity by PFGE and ribotyping. Strains obtained from poultry showed more variations in their PFGE patterns and ribotypes, although the patterns were still closely related. In addition, SphI ribotypes A and D among the Swiss strains correlated with phage types 4 and 8, respectively. No correlation of phage types with PFGE pattern was noted. Both PFGE and ribotyping indicate that the S. enteritidis strains circulating in Malaysia and Switzerland are very similar and may be clonally related. Comparison of the PFGE patterns with the ribotypes for 23 Swiss and 16 Malaysian isolates showed that there was a 69% concordance in the grouping of isolates. We conclude that the close genetic similarity observed between epidemiologically unrelated and outbreak-related isolates of S. enteritidis suggests that both PFGE and ribotyping are of limited value in the epidemiological analysis of these particular isolates, possibly because of the highly clonal nature of pathogenic strains of S. enteritidis.
    Matched MeSH terms: Bacterial Typing Techniques/statistics & numerical data
  5. Characterization of group A streptococci isolated in Kuala Lumpur, Malaysia
    Jamal F, Pit S, Johnson DR, Kaplan EL
    J Trop Med Hyg, 1995 Oct;98(5):343-6.
    PMID: 7563264
    T-agglutination patterns of 190 strains of group A streptococci isolated between January 1989 and December 1993 from body fluids (10), throat culture (56), pus (51) and skin lesions (73) were determined. Mucoid colonial morphology was exhibited by 6.3% (12/190) of the strains on initial isolation. Type T-5,11,27,44 comprised 23.7%, followed by T-1,3,13,B3264 (11.1%), T-4,6 (8.4%) and T-8,25, Imp 19 (7.9%). About 42% (80/190) strains could not be characterized by T agglutination pattern. T-typing of 71 selected strains at WHO Collaborating Center, Minneapolis yielded similar results. Nineteen selected strains were further characterized by M-typing; only three strains were M-typeable. These strains were isolated from throat (M1), sputum (M5) and pus (M12). About 68% (48/71) isolates produced serum opacity factor. These data support the existence of as yet uncharacterized group A streptococcal serotypes in this region.
    Matched MeSH terms: Bacterial Typing Techniques
  6. Molecular analysis of environmental and human isolates of Salmonella typhi
    Thong KL, Cordano AM, Yassin RM, Pang T
    Appl Environ Microbiol, 1996 Jan;62(1):271-4.
    PMID: 8572705
    Molecular characterization of a total of 54 isolates of Salmonella typhi from Santiago, Chile, was performed by pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with three restriction endonucleases: XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3'), and SpeI (5'-ACTAGT-3'). Thirteen of the 54 isolates were obtained from environmental sources (sewage and river water), and the rest were isolates from clinical cases of typhoid fever. Considerable genetic diversity was detected among the human isolates obtained in 1994, as evidenced by the presence of 14 to 19 different PFGE patterns among 20 human isolates, with F (coefficient of similarity) values ranging from 0.69 to 1.0 (XbaI), 0.61 to 1.0 (AvrII), and 0.70 to 1.0 (SpeI). A total of eight phage types were detected among these 20 isolates, with 50% possessing the E1 or 46 phage type. There was no correlation between PFGE pattern and phage types. Similar diversity was seen among 21 isolates obtained in 1983, with 17 to 19 PFGE patterns detected and F values of 0.56 to 1.0 (XbaI), 0.55 to 1.0 (AvrII), and 0.67 to 1.0 (SpeI). Comparison of these two groups of human isolates obtained 11 years apart indicated that certain molecular types of S. typhi are shared and are able to persist for considerable periods. A similar degree of genetic diversity was also detected among the environmental isolates of S. typhi, for which 10 to 12 different PFGE patterns were detected among the 13 isolates analyzed, with F values ranging from 0.56 to 1.0 (XbaI), 0.52 to 1.0 (AvrII), and 0.69 to 1.0 (SpeI). Certain molecular types present among the environmental isolates of S. typhi were also found among the human isolates from the same time period, providing evidence for the epidemiological link between environmental reservoirs and human infection.
    Matched MeSH terms: Bacterial Typing Techniques
  7. 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: Bacterial Typing Techniques*
  8. Fulltext Outbreak of Salmonella enteritidis gastroenteritis: investigation by pulsed-field gel electrophoresis
    Thong KL, Puthucheary S, Pang T
    Int J Infect Dis, 1998 Jan-Mar;2(3):159-63.
    PMID: 9531664
    OBJECTIVE: Pulsed-field gel electrophoresis (PFGE) was used to investigate an outbreak of gastroenteritis caused by Salmonella enteritidis. The outbreak occurred among university undergraduates who consumed contaminated food.
    METHOD: Molecular typing was done by analyzing DNA band patterns of isolates of S. enteritidis after digestion of chromosomal DNA with infrequently-cutting restriction endonucleases XbaI, AvrII, and SpeI and separation of DNA fragments using PFGE.
    RESULTS: Twenty-nine outbreak isolates of S. enteritidis had identical or highly similar PFGE patterns, whereas different PFGE patterns were observed among three epidemiologically unrelated isolates obtained during the same period.
    CONCLUSION: The data obtained confirm the value of PFGE in epidemiologic investigations of outbreaks caused by S. enteritidis.
    Matched MeSH terms: Bacterial Typing Techniques
  9. Convenient and versatile DNA extraction using agarose plugs for ribotyping of problematic bacterial species
    Nair S, Karim R, Cardosa MJ, Ismail G, Pang T
    J Microbiol Methods, 1999 Oct;38(1-2):63-7.
    PMID: 10520586
    We describe a convenient, versatile and safe method for preparing bacterial DNA for ribotyping analysis. In this method, extraction of bacterial DNA from Salmnonella typhi and Burkholderia pseudomallei. and subsequent restriction endonuclease digestion, was performed in agarose blocks/plugs thus minimizing shearing and loss of DNA, problems commonly associated with liquid phase phenol extraction. Digested DNA in the plugs was then electrophoresed directly, transferred to nylon membranes and hybridized with labeled rDNA probes in the usual manner to provide reproducible restriction patterns. This method is particularly useful for bacterial species where standard DNA extraction in the liquid phase using phenol has been problematic (e.g. B. pseudomallei) but can be used for any bacterial species. The DNA extracted within the agarose plugs can be stored for long periods and can be used in other, widely-used typing methods such as pulsed-field gel electrophoresis (PFGE) and PCR-based techniques. Embedding live cells directly in agarose plugs also minimizes the risk of exposure to these virulent human pathogens among laboratory workers.
    Matched MeSH terms: Bacterial Typing Techniques
  10. Fulltext New emm (M protein gene) sequences of group A streptococci isolated from Malaysian patients
    Jamal F, Pit S, Facklam R, Beall B
    Emerg Infect Dis, 1999 Jan-Feb;5(1):182-3.
    PMID: 10081694
    Matched MeSH terms: Bacterial Typing Techniques
  11. Molecular evidence of clonality amongst Vibrio cholerae O1 biotype El Tor during an outbreak in Malaysia
    Vadivelu J, Iyer L, Kshatriya BM, Puthucheary SD
    Epidemiol Infect, 2000 Feb;124(1):25-30.
    PMID: 10722126
    Forty-three clinical strains of V. cholerae O1 biotype E1 Tor were isolated between 3 May and 10 June 1998 during an outbreak in the metropolitan area of Kuala Lumpur and its suburbs. With the exception of three Inaba strains that were restricted to three members of a family, all the others belonged to the Ogawa serotype. The strains were analysed for clonality using ribotyping and pulsed-field gel electrophoresis (PFGE). Two ribotypes, V/B21a and B27, were identified among 40 Ogawa isolates using BglI restriction endonuclease. Ribotype V/B21a has been described previously from Taiwan and Colombia and several Asian countries while B27 has been reported among isolates from Senegal. The three Inaba strains belonged to one ribotype, designated type A, not previously reported. PFGE analysis using NotI revealed that all isolates within a ribotype had identical profiles demonstrating clonality amongst the strains. Dice coefficient analysis of the two Ogawa genotypes revealed 89% similarity on ribotype patterns and 91.3% on PFGE profiles. Ribotype V/B21a isolates were associated with cases from dispersed areas of Kuala Lumpur and its suburbs while ribotype B27 was restricted to cases from one particular area suggesting a common-source outbreak.
    Matched MeSH terms: Bacterial Typing Techniques
  12. Characterization of Burkholderia pseudomallei isolated in Thailand and Malaysia
    Radua S, Ling OW, Srimontree S, Lulitanond A, Hin WF, Yuherman, et al.
    Diagn Microbiol Infect Dis, 2000 Nov;38(3):141-5.
    PMID: 11109011
    A total of 35 Burkholderia pseudomallei isolates from Thailand (16 clinical and eight soil isolates) and Malaysia (seven animal, two isolate each from clinical and soil) were investigated by their antimicrobial resistance, plasmid profiles and were typed by randomly amplified polymorphic DNA analysis. All isolates were found to be resistant to six or more of the 12 antimicrobial agents tested. Only two small plasmids of 1.8 and 2.4 megadalton were detected in two clinical isolates from Thailand. RAPD analysis with primer GEN2-60-09 resulted in the identification of 35 RAPD-types among the 35 isolates. The constructed dendrogram differentiated the 35 isolates into two main clusters and a single isolate. The wide genetic biodiversity among the 35 isolates indicate that RAPD-PCR can be a useful method to differentiate unrelated B. pseudomallei in epidemiological investigation.
    Matched MeSH terms: Bacterial Typing Techniques
  13. Enzyme biotypes of Helicobacter pylori isolated from Penang, Peninsular Malaysia
    Uyub AM, Azlan AA
    Southeast Asian J. Trop. Med. Public Health, 2000 Dec;31(4):693-6.
    PMID: 11414414
    A total of 52 clinical strains of Helicobacter pylori were characterized on the basis of preformed enzyme production with API ZYM kits. Using the biotyping schemes as defined by Reina and Alomar (1989), Kung et al (1989) and Matsumoto et al (1996), 15.3% (8/52), 13.5% (7/52) and 11.5% (6/52) of the isolates were not biotypable, respectively. Two enzymes, valine arylamidase and cystine arylamidase could be additionally used to differentiate between isolates. Our isolates were either negative or positive for both the enzymes or positive only for cystine arylamidase. We propose the incorporation of these two enzymes into the Matsumoto et al (1996) biotyping scheme to biotype strains into additional enzyme biotypes.
    Matched MeSH terms: Bacterial Typing Techniques/methods*
  14. Multidrug-resistant strains of Salmonella enterica serotype typhi are genetically homogenous and coexist with antibiotic-sensitive strains as distinct, independent clones
    Thong KL, Bhutta ZA, Pang T
    Int J Infect Dis, 2000;4(4):194-7.
    PMID: 11231181
    OBJECTIVE: The goal of this study was to report the molecular analysis of antibiotic-sensitive and multidrug-resistant (MDR) strains of Salmonella typhi, using pulsed-field gel electrophoresis (PFGE), with a particular emphasis on the coexistence of these strains in a typhoid-endemic region of Karachi, Pakistan.

    METHODS: One hundred isolates of S. typhi in humans (50 MDR and 50 antibiotic-sensitive isolates) from sporadic cases of typhoid fever were analyzed by Vi-phage typing, antibiograms and PFGE.

    RESULTS: The MDR S. typhi strains were resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole. Analysis by PFGE showed that 50 MDR isolates of S. typhi had a single, homogenous PFGE profile, which was distinctly different from that of 50 antibiotic-sensitive isolates obtained in the same time frame from the same area. This latter group of isolates showed much greater diversity of PFGE profiles, as has been observed in other endemic regions.

    CONCLUSIONS: Multidrug-resistant and antibiotic-susceptible strains of S. typhi can coexist in endemic areas as epidemiologically independent pathogens and are not in competition for continued persistence and transmission.

    Matched MeSH terms: Bacterial Typing Techniques*
  15. Detection of Escherichia coli O157:H7 by multiplex PCR and their characterization by plasmid profiling, antimicrobial resistance, RAPD and PFGE analyses
    Radu S, Ling OW, Rusul G, Karim MI, Nishibuchi M
    J Microbiol Methods, 2001 Aug;46(2):131-9.
    PMID: 11412923
    Twenty-five and three strains of Escherichia coli O157:H7 were identified from 25 tenderloin beef and three chicken meat burger samples, respectively. The bacteria were recovered using the immunomagnetic separation procedure followed by selective plating on sorbitol MacConkey agar and were identified as E. coli serotype O157:H7 with three primer pairs that amplified fragments of the SLT-I, SLT-II and H7 genes in PCR assays. Susceptibility testing to 14 antibiotics showed that all were resistant to two or more antibiotics tested. Although all 28 strains contained plasmid, there was very little variation in the plasmid sizes observed. The most common plasmid of 60 MDa was detected in all strains. We used DNA fingerprinting by randomly amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) to compare the 28 E. coli O157:H7 strains. At a similarity level of 90%, the results of PFGE after restriction with XbaI separated the E. coli O157:H7 strains into 28 single isolates, whereas RAPD using a single 10-mer oligonucleotides separated the E. coli O157:H7 strains into two clusters and 22 single isolates. These typing methods should aid in the epidemiological clarification of the E. coli O157:H7 in the study area.
    Matched MeSH terms: Bacterial Typing Techniques
  16. Characterization of Salmonella serovars by PCR-single-strand conformation polymorphism analysis
    Nair S, Lin TK, Pang T, Altwegg M
    J Clin Microbiol, 2002 Jul;40(7):2346-51.
    PMID: 12089246
    PCR-restriction fragment length polymorphism (PCR-RFLP) and PCR-single-strand conformation polymorphism (PCR-SSCP) analyses were carried out on the 1.6-kb groEL gene from 41 strains of 10 different Salmonella serovars. Three HaeIII RFLP profiles were recognized, but no discrimination between the serovars could be achieved by this technique. However, PCR-SSCP analysis of the groEL genes of various Salmonella serovars produced 14 SSCP profiles, indicating the potential of this technique to differentiate different Salmonella serovars (interserovar differentiation). Moreover, PCR-SSCP could differentiate strains within a subset of serovars (intraserovar discrimination), as three SSCP profiles were produced for the 11 Salmonella enterica serovar Enteritidis strains, and two SSCP profiles were generated for the 7 S. enterica serovar Infantis and five S. enterica serovar Newport strains. PCR-SSCP has the potential to complement classical typing methods such as serotyping and phage typing for the typing of Salmonella serovars due to its rapidity, simplicity, and typeability.
    Matched MeSH terms: Bacterial Typing Techniques
  17. Nosocomial outbreak of Enterobacter gergoviae bacteraemia in a neonatal intensive care unit
    Ganeswire R, Thong KL, Puthucheary SD
    J Hosp Infect, 2003 Apr;53(4):292-6.
    PMID: 12660126
    A nosocomial outbreak of bacteraemia, caused by Enterobacter gergoviae infected 11 babies, nine of whom were premature, and was investigated in the neonatal intensive care unit (NICU) of a general hospital in Johor Bahru, Malaysia. The strain that was isolated from the babies was also isolated from the dextrose saline used for the dilution of parenteral antibiotics and from the hands of a healthcare worker on duty in the nursery. Pulsed-field gel electrophoresis (PFGE) of Xba I-digested chromosomal DNA confirmed a possible cross-contamination of parenteral dextrose saline and the healthcare worker. Prompt and effective control measures were initiated within NICU and the nosocomial infection of E. gergoviae was brought to an abrupt end. To the best of our knowledge, this is the first documented outbreak of E. gergoviae in the NICU in a hospital in the state of Johor, Malaysia.
    Matched MeSH terms: Bacterial Typing Techniques
  18. Molecular typing of Salmonella enterica serovar typhi isolates from various countries in Asia by a multiplex PCR assay on variable-number tandem repeats
    Liu Y, Lee MA, Ooi EE, Mavis Y, Tan AL, Quek HH
    J Clin Microbiol, 2003 Sep;41(9):4388-94.
    PMID: 12958274
    A multiplex PCR method incorporating primers flanking three variable-number tandem repeat (VNTR) loci (arbitrarily labeled TR1, TR2, and TR3) in the CT18 strain of Salmonella enterica serovar Typhi has been developed for molecular typing of S. enterica serovar Typhi clinical isolates from several Asian countries, including Singapore, Indonesia, India, Bangladesh, Malaysia, and Nepal. We have demonstrated that the multiplex PCR could be performed on crude cell lysates and that the VNTR banding profiles produced could be easily analyzed by visual inspection after conventional agarose gel electrophoresis. The assay was highly discriminative in identifying 49 distinct VNTR profiles among 59 individual isolates. A high level of VNTR profile heterogeneity was observed in isolates from within the same country and among countries. These VNTR profiles remained stable after the strains were passaged extensively under routine laboratory culture conditions. In contrast to the S. enterica serovar Typhi isolates, an absence of TR3 amplicons and a lack of length polymorphisms in TR1 and TR2 amplicons were observed for other S. enterica serovars, such as Salmonella enterica serovar Typhimurium, Salmonella enterica serovar Enteritidis, and Salmonella enterica serovar Paratyphi A, B, and C. DNA sequencing of the amplified VNTR regions substantiated these results, suggesting the high stability of the multiplex PCR assay. The multiplex-PCR-based VNTR profiling developed in this study provides a simple, rapid, reproducible, and high-resolution molecular tool for the epidemiological analysis of S. enterica serovar Typhi strains.
    Matched MeSH terms: Bacterial Typing Techniques/methods*
  19. Research note: Molecular subtyping of Salmonella enterica serovar Tshiongwe recently isolated in Malaysia during 2001-2002
    Thong KL, Bakeri SA, Lai KS, Koh YT, Taib MZ, Lim VK, et al.
    Southeast Asian J. Trop. Med. Public Health, 2004 Mar;35(1):92-6.
    PMID: 15272750
    Pulsed field gel electrophoresis (PFGE) and antimicrobial susceptibility analysis were undertaken on twenty-three strains of Salmonella enterica serovar Tshiongwe, an unusual serovar, which recently emerged in Malaysia. Antimicrobial susceptibility analysis showed that all the strains were sensitive to ampicilin, chloramphenicol, cotrimoxazole, and kanamycin. Twenty (87%) and 8 (3.5%) strains had resistance to tetracycline and streptomycin respectively. PFGE analysis subtyped 23 strains into 10 profiles (Dice coefficient of similarity, F = 0.7-1.0). The predominant profile, X1 was found in both clinical and environmental isolates and was widely distributed in different parts of Malaysia during the study period. In addition, isolates recovered from food, a hand-towel, apron and the surface of a table-top in one particular location had unique, indistinguishable profiles (X4/4a) and identical antibiograms. Similarly, isolates from cooked meat and a chopping board had PFGE profiles similar to some human isolates. These probably indicated cross-contamination and poor hygiene in food practices, hence contributing to Salmonellosis. Factors causing the emergence of this rare Salmonella serovar being responsible for food poisoning episodes during the study period remained unclear. The study reiterated the usefulness and versatility of PFGE in the molecular subtyping of this rare Salmonella serovar in Malaysia.
    Matched MeSH terms: Bacterial Typing Techniques
  20. Phenotypic and genotypic characteristics and epidemiological significance of ctx+ strains of Vibrio cholerae isolated from seafood in Malaysia
    Chen CH, Shimada T, Elhadi N, Radu S, Nishibuchi M
    Appl Environ Microbiol, 2004 Apr;70(4):1964-72.
    PMID: 15066786
    Of 97 strains of Vibrio cholerae isolated from various seafoods in Malaysia in 1998 and 1999, 20 strains carried the ctx gene and produced cholera toxin. Fourteen, one, and five of these toxigenic strains belonged to the O139, O1 Ogawa, and rough serotypes, respectively. The rough strains had the rfb gene of the O1 serotype. The toxigenic strains varied in their biochemical characteristics, the amount of cholera toxin produced, their antibiograms, and the presence or absence of the pTLC plasmid sequence. DNA fingerprinting analysis by arbitrarily primed PCR, ribotyping, and a pulsed-field gel electrophoresis method classified the toxigenic strains into 3, 7, and 10 types, respectively. The relatedness of these toxigenic strains to clinical strains isolated in other countries and from international travelers was examined by using a dendrogram constructed from the pulsed-field gel electrophoresis profiles. The results of the examination of the antibiogram and the possession of the toxin-linked cryptic plasmid were consistent with the dendrogram-based relatedness: the O139 strains isolated from Malaysian seafoods could be separated into two groups that appear to have been introduced from the Bengal area independently. The rough strains of Malaysian seafood origin formed one group and belonged to a cluster unique to the Thailand-Malaysia-Laos region, and this group may have persisted in this area for a long period. The single O1 Ogawa strain detected in Malaysian seafood appears to have an origin and route of introduction different from those of the O139 and the rough strains.
    Matched MeSH terms: Bacterial Typing Techniques
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