Displaying publications 1 - 20 of 224 in total

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  1. Koh CL, Kok CH
    PMID: 6377513
    Fifteen independent E. coli strains of avian, bovine and porcine origin in Peninsular Malaysia were tested for antibiotic resistance and conjugative R plasmids. Eight (53%) isolates were found to be antibiotic resistant. Among them, 37.5% were mono-resistant and 62.5% were resistant to three or more antibiotics, i.e., multi-resistant. All of them were resistant to Tc and sensitive to Gm and Nx. Three of the eight antibiotic resistant strains were able to transfer all or part of their resistance to an E. coli K12 recipient by conjugation. The transfer frequencies of Km, Sm and Tc resistance of the three donors varied between 4.5 X 10(-8) to 6.8 X 10(-7). Analysis of the plasmid profiles of all the three donors and their respective transconjugants after agarose gel electrophoresis provided conclusive evidence that the transferable resistance traits were plasmid-mediated.
    Matched MeSH terms: Plasmids/drug effects*
  2. Koh CL, Kalaimathee KK, Ngeow YF
    Med J Malaysia, 1984 Dec;39(4):269-71.
    PMID: 6443581
    The plasmid profiles of 66 strains of penicillinase-producing Neisseria gonorrhoeae (PPNG), isolated in Peninsular Malaysia, were determined by agarose gel electrophoresis. All the isolates harboured two common plasmid species, a 4.4 x 10 6 Far-East type R plasmid associated with beta-lactamase production and a 2.6 x 106 plasmid of unknown function. In addition to these two plasmids, 51 (77%) PPNG isolates also carried a 24.5 x 106 conjugative plasmid.
    Matched MeSH terms: Plasmids*
  3. Kalaimathee KK, Koh CL, Ngeow YF
    Microbiol. Immunol., 1985;29(10):921-6.
    PMID: 3935906
    The plasmid profiles of 160 strains of Neisseria gonorrhoeae isolated in Peninsular Malaysia, comprising 80 penicillinase-producing (PPNG) and 80 non-penicillinase-producing (non-PPNG) isolates, were determined. The 80 PPNG isolates were divided into two plasmid groups. All of them harbored two common plasmid species, a 4.4 megadalton (Md) R plasmid previously associated with beta-lactamase production in PPNG strains from the Far East and a 2.6 Md multicopy plasmid of unknown function. In addition to these two plasmids, 60 (75%) PPNG isolates also carried a large 24.5 Md conjugative plasmid. In contrast, the 80 non-PPNG strains were divided into three plasmid groups. All of them possessed the 2.6 Md cryptic plasmid, and 35 (44%) isolates also harbored the 24.5 Md transfer plasmid. Besides these two plasmids, one non-PPNG isolate carried an additional 7.8 Md cryptic plasmid.
    Matched MeSH terms: Plasmids*
  4. Dillon JR, Bygdeman SM, Sandström EG
    Genitourin Med, 1987 Jun;63(3):160-8.
    PMID: 3111978
    One hundred and thirty eight penicillinase producing Neisseria gonorrhoeae (PPNG) and 239 non-PPNG strains were characterised serologically using a panel of seven monoclonal antibodies directed against protein 1A and seven against protein 1B. An association between serovar and susceptibility to antimicrobial agents, auxotype, and plasmid content was observed. Serogroup WI strains were more sensitive to penicillin, ampicillin, tetracycline, erythromycin, cefoxitin, and cefuroxime. Sixty five (82%) of the 79 WI strains were typed as being serovar Aedgkih, and 47 (72%) of these strains required arginine, uracil, and hypoxanthine for growth (AUH-). Seventy one (44%) of 160 WII/WIII strains were serovar Bacejk, and 42 (59%) of these required proline, citrulline, and uracil for growth (PCU-) and were plasmid free. Serovars Bcgk, Beghjk, Bacjk, and Bajk were associated with resistance to antimicrobial agents. Analysis of PPNG isolates showed a new serovar, Af, which was associated with strains imported from Malaysia and Singapore that required proline and ornithine for growth (Pro-Orn-) and carried the 24.5 megadalton transfer plasmid, the 2.6 megadalton cryptic plasmid, and the 4.5 megadalton penicillinase producing plasmid. Other associations between serovar and geographical location were noted.
    Matched MeSH terms: Plasmids
  5. Mohamed R, Lavin MF
    Biochem Biophys Res Commun, 1989 Feb 15;158(3):749-54.
    PMID: 2537634
    Anomalies in DNA replication, repair and recombination in ataxia-telangiectasia (A-T) point to a defect in structure or function of chromatin. In this study we have compared DNA-protein binding in nuclear extracts from control and A-T cells using two assay systems, filter-binding and DNA-accessibility. Interestingly, the extent of DNA protein binding over a range of protein concentration was significantly lower in A-T extracts. In addition the accessibility of the restriction enzyme Eco R1 to protein-bound plasmid was greater when A-T extracts were used. This is in keeping with the reduced binding observed in the filter-binding assay.
    Matched MeSH terms: Plasmids
  6. Phipps M, Pang T, Koh CL, Puthucheary S
    Microbiol. Immunol., 1991;35(2):157-61.
    PMID: 1886492
    Seven (6.1%) of 115 strains of Salmonella typhi isolated from Malaysian patients harbored a single large plasmid of 71 to 166 mD. Two of the seven plasmid-bearing strains were resistant to chloramphenicol (Cm) and tetracycline (Tc) and they transferred Cm and Tc resistance traits to Escherichia coli K12 at frequencies from 1.6 x 10(-7) to 1.9 x 10(-6). Agarose gel electrophoresis provided evidence that the resistance traits were cotransferred on a conjugative plasmid. The significance and importance of these results are discussed.
    Matched MeSH terms: Plasmids*
  7. Ansary A, Radu S
    FEMS Microbiol Lett, 1992 Mar 01;70(2):125-8.
    PMID: 1587459
    Six Campylobacter jejuni clinical isolates were examined for the occurrence of plasmids in association with antibiotic resistances as well as conjugal transfer. All the isolates were found to carry three similar plasmids of 78 kb, 12.6 kb and 3.3 kb in size. Multiple resistance to at least three of the antibiotics tested was observed with resistance to tetracycline most common. En bloc transfer of donor resistances at frequencies ranging from 10(-8) to 10(-4) were seen in all but one of the isolates during conjugation. The conjugal transfer of erythromycin, neomycin and streptomycin were observed to occur at frequencies similar to that of chloramphenicol, kanamycin and tetracycline. In isolate ABA94, three different antibiotic resistance phenotypes of the transconjugants were seen. In addition to en bloc transfer of the donor resistances, in approximately 10% of the transconjugants the streptomycin resistance was lost although these transconjugants carried the donor complement of three plasmids. In a further 1% of the transconjugants, resistance to kanamycin only was detected and these transconjugants did not carry any plasmids.
    Matched MeSH terms: Plasmids*
  8. Pang T, Altwegg M, Martinetti G, Koh CL, Puthucheary S
    Microbiol. Immunol., 1992;36(5):539-43.
    PMID: 1513268
    Genetic variation among Malaysian isolates of Salmonella typhi was determined by analysis of ribosomal RNA gene restriction patterns. Of the 20 isolates analyzed, eight different pattern combinations were detected. The amount of variation observed was also dependent upon the restriction endonuclease used; PstI produced more different patterns than did SmaI. The results suggested that disease activity was due to a number of different clones circulating simultaneously rather than a single strain. Further implications of the data are discussed.
    Matched MeSH terms: Plasmids
  9. Seleena P, Lee HL
    PMID: 7855665
    Matched MeSH terms: Plasmids/analysis; Plasmids/isolation & purification*
  10. Vadivelu J, Puthucheary SD, Phipps M, Chee YW
    J Med Microbiol, 1995 Mar;42(3):171-4.
    PMID: 7884797
    Eighteen strains of Aeromonas hydrophila from patients with bacteraemia were investigated for possible virulence factors. Cytotoxin and haemolysin were produced by all strains, whereas cholera toxin-like factor was produced by 33% of strains only. Enterotoxin production was not detected. Haemagglutination of guinea-pig, fowl and rabbit erythrocytes was demonstrated by 83%, 67% and 61% of strains, respectively. Fucose- and mannose-sensitive haemagglutinins were predominant. None of the strains agglutinated sheep erythrocytes. Extrachromosomal DNA was detected in 17 strains, 16 of which had a plasmid (3.6-5.1 MDa), the majority being between 4.6 and 5.1 MDa.
    Matched MeSH terms: Plasmids
  11. Son R, Ansary A, Salmah I, Maznah A
    World J Microbiol Biotechnol, 1995 May;11(3):315-8.
    PMID: 24414656 DOI: 10.1007/BF00367107
    Thirty-five veterinary isolates of Salmonella enteritidis were characterized by their susceptibility to 10 antimicrobial agents and by their plasmid profiles on agarose gel electrophoresis. All were susceptible to carbenicillin, chloramphenicol and nalidixic acid but 89% were resistant to tetracycline. When examined, 91% of the isolates harboured plasmids, with sizes ranging from 9.8 to 60 MDa. However, it was only possible to associate the presence of plasmids with tetracycline resistance; plasmids occurring in 90% of the tetracycline-resistant isolates. In conjugation experiments, with Escherichia coli K12 Nal(r) as recipient, the tetracycline resistance in three selected S. enteritidis isolates was observed to transfer at frequencies of 3.0×10(-3) to 1.0×10(-2)/donor cell. The concomitant transfer of a 56-MDa or 60-MDa plasmid in these three S. enteritidis isolates was also detected.
    Matched MeSH terms: Plasmids
  12. Kawalek MD, Benjamin S, Lee HL, Gill SS
    Appl Environ Microbiol, 1995 Aug;61(8):2965-9.
    PMID: 7487029
    A new mosquitocidal Bacillus thuringiensis subsp., jegathesan, has recently been isolated from Malaysia. Parasporal crystal inclusions were purified from this strain and bioassayed against fourth-instar larvae of Culex quinquefasciatus, Aedes aegypti, Aedes togoi, Aedes albopictus, Anopheles maculatus, and Mansonia uniformis. The 50% lethal concentration of crystal inclusions for each species was 0.34, 8.08, 0.34, 17.59, 3.91, and 120 ng/ml, respectively. These values show that parasporal inclusions from this new subspecies have mosquitocidal toxicity comparable to that of inclusions isolated from B. thuringiensis subsp. israelensis. Solubilized and chymotrypsin-activated parasporal inclusions possessed low-level hemolytic activity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the crystals were composed of polypeptides of 77, 74, 72, 68, 55, 38, 35, 27, and 23 kDa. Analysis by Western blotting (immunoblotting) with polyclonal antisera raised against toxins purified from B. thuringiensis subsp. israelensis reveals that proteins in parasporal inclusions of subsp. jegathesan are distinct, because little cross-reactivity was shown. Analysis of the plasmid content of B. thuringiensis subsp. jegathesan indicates that the genes for toxin production may be located on 105- to 120-kb plasmids. Cry- clones that have been cured of these plasmids are nontoxic. Southern blot analysis of plasmid and chromosomal DNA from subsp. jegathesan showed little or low homology to the genes coding for CryIVA, CryIVB, and CryIVD from B. thuringiensis subsp. israelensis.
    Matched MeSH terms: Plasmids/genetics
  13. Son R, Ansary A, Rusul G, Karim MI
    World J Microbiol Biotechnol, 1996 May;12(3):243-6.
    PMID: 24415231 DOI: 10.1007/BF00360921
    Three strains of verotoxin-producing Escherichia coli isolated from patients with haemorrhagic colitis harboured plasmids ranging in size from 2.7 kb to 91.2 kb. Those plasmids ranging from 2.7 kb to 6.8 kb hybridized to Shiga-like toxin I and Shiga-like toxin II gene probes.
    Matched MeSH terms: Plasmids
  14. Koay AS, My R, Cheong YM
    J Clin Microbiol, 1996 Jul;34(7):1863-5.
    PMID: 8784614
    Between 1992 and 1994, 253 tetracycline-resistant Neisseria gonorrhoeae (TRNG) strains were isolated and characterized by auxotype and serogroup (A/S) classes to study TRNG prevalence in different years. TRNG accounted for 28.1, 42.5, and 51.9% of the strains isolated in 1992, 1993, and 1994, respectively, showing a significant increase in each successive year (chi square = 26.7, P < 0.001). There was no significant increase in penicillinase-producing TRNG, which accounted for 53.1, 53.8, and 63.2% of the TRNG isolates. The 253 TRNG isolates belonged to 53 A/S classes. Eighteen A/S classes not observed in 1992 were detected in 1993, and 11 A/S classes not observed in 1992 and 1993 were isolated in 1994, indicating dissemination of the tetracycline resistance gene among the N. gonorrhoeae strains in Malaysia. Its emergence and subsequent rapid spread are alarming. The plasmid is capable of self-transfer (S.A. Morse, S.R. Johnson, J.W. Biddle, and M.C. Roberts, J. Infect. Dis. 155:819-822, 1987), allowing further dissemination of tetracycline resistance.
    Matched MeSH terms: Plasmids/genetics
  15. Son R, Rusu G, Karim MI
    J Appl Microbiol, 1997 Feb;82(2):240-4.
    PMID: 12452600
    Thirty-six strains of Escherichia coli isolated from animals in Bario, a remote area in Sarawak, Malaysia, were examined for presence of plasmid DNA and their susceptibility to nine antimicrobial agents. Of the total 36 isolates, five bovine and six canine isolates were found to contain plasmid DNA ranging in sizes from 2.6 to 70 kilobases. All were susceptible to chloramphenicol, erythromycin, gentamicin, nalidixic acid and neomycin but resistance to ampicillin (47%), erythromycin (19%), streptomycin (25%) and tetracycline (11%) was observed. Resistance was associated with carriage of a 47 kb (SC98), 70 kb, (SC133) and 56 and 4.6 kb (SC119) plasmids which were transmissible to the Escherichia coli K12 recipient. It is concluded that animals form a potential reservoir of R plasmids carrying E. coli in the study area.
    Matched MeSH terms: Plasmids/drug effects; Plasmids/genetics*
  16. Naidu AJ, Yadav M
    J Med Microbiol, 1997 Oct;46(10):833-8.
    PMID: 9364139
    Aeromonas hydrophila strains obtained from diarrhoeal samples of human patients (19 isolates) and freshwater ponds (11 isolates) were analysed for siderophore production. Both clinical and environmental isolates showed significantly increased siderophore production under iron-limiting conditions both at 28 degrees C and at 37 degrees C. Clinical isolates consistently produced higher levels of siderophores than did the environmental isolates. The role of plasmids in moderating siderophore production was studied after curing with acridine orange. Treatment with acridine orange for 24 h removed the larger plasmids but the smaller plasmids (< 5 MDa), more common in the environmental isolates, were resistant to curing. As found in the untreated isolates, the cured clinical isolates produced higher mean levels of siderophores than the cured environmental isolates. Siderophore production in A. hydrophila was significantly influenced by iron-limiting cultural conditions and the source of isolates, but plasmid content and growth temperature at 28 degrees C or 37 degrees C had little effect on production. The basis for the greater production of siderophores in clinical isolates than in environmental isolates needs further study.
    Matched MeSH terms: Plasmids
  17. Barloy F, Lecadet MM, Delécluse A
    Gene, 1998 May 12;211(2):293-9.
    PMID: 9602158
    Three new open reading frames were found downstream from cbm71, a toxin gene from Clostridium bifermentans malaysia (Cbm) strain CH18. The first one (91bp downstream) called cbm72, is 1857bp long and encodes a 71727-Da protein (Cbm72) with a sequence similar to that of Bacillus thuringiensis delta-endotoxins. This protein shows no significant toxicity to mosquito larvae. The two others, cbm17.1 (462bp) and cbm17.2 (459bp), are copies of the same gene encoding Cbm P18 and P16 polypeptides and located 426bp and 1022bp downstream from cbm72, respectively. They encode 17189-Da and 17451-Da proteins with sequences 44.6% similar to that of Aspergillus fumigatus hemolysin; however, they were not hemolytic in the conditions tested.
    Matched MeSH terms: Plasmids/genetics
  18. Radu S, Elhadi N, Hassan Z, Rusul G, Lihan S, Fifadara N, et al.
    FEMS Microbiol Lett, 1998 Aug 01;165(1):139-43.
    PMID: 9711850
    Antibiotic susceptibility, plasmid profiles and random amplification of polymorphic DNA (RAPD) were used to study strains of Vibrio vulnificus isolated from cockles (Anadara granosa). Thirty-six isolates were analyzed. The prevalent biotypes were 1 (72.2% of the isolates) and 2 (27.8%). Among these, 21 strains of biotype 1 and two strains of biotype 2 contained plasmid DNA bands ranging in size from 1.4 to 9.7 MDa. Thirty-one (83.3%) were found to be resistant to one or more of the antimicrobial agents tested, however no specific correlation between antimicrobial resistance patterns and a single biotype was found. In addition, no particular plasmid profile was predictive of a particular pattern of antibiotic susceptibility. Two primers produced polymorphisms in all strains tested, producing bands ranging from 0.25 to 2.7 kb, indicating a high variability among both biotype 1 and biotype 2 of the V. vulnificus strains investigated. RAPD identity across biotypes was also observed among Vibrio vulnificus strains.
    Matched MeSH terms: Plasmids/genetics*
  19. Son R, Nimita F, Rusul G, Nasreldin E, Samuel L, Nishibuchi M
    Lett Appl Microbiol, 1999 Aug;29(2):118-22.
    PMID: 10499300
    Nineteen strains of vancomycin-resistant Enterococcus faecium isolated from 10 of 75 (13.3%) tenderloin beef samples were examined for resistance to selected antibiotics, presence of plasmids, and genetic diversity by random amplification of polymorphic DNA analysis. All strains showed multiple resistant to the antibiotics tested. Multiple antibiotic indexing of the vancomycin-resistant E. faecium strains showed that all (100%) originated from high risk contamination environments where antibiotics were often used. Plasmids ranging in size from 1.5 to 36 megadalton were detected in 15 of 19 (79%) strains. Thus, three plasmid profiles and eight antibiotypes were observed among the E. faecium strains. A high degree of polymorphism was obtained by combining the results of the two primers used; with the 19 E. faecium strains being differentiated into 19 RAPD-types. These preliminary results suggest that RAPD-PCR has application for epidemiologic studies and that resistance patterns and plasmid profiling could be used as an adjunct to RAPD for the typing of E. faecium in the study area.
    Matched MeSH terms: Plasmids/analysis
  20. Radu S, Ho YK, Lihan S, Yuherman, Rusul G, Yasin RM, et al.
    Epidemiol Infect, 1999 Oct;123(2):225-32.
    PMID: 10579441
    A total of 31 strains of Vibrio cholerae O1 (10 from outbreak cases and 7 from surface water) and non-O1 (4 from clinical and 10 from surface water sources) isolated between 1993 and 1997 were examined with respect to presence of cholera enterotoxin (CT) gene by PCR-based assays, resistance to antibiotics, plasmid profiles and random amplified polymorphic DNA (RAPD) analysis. All were resistant to 9 or more of the 17 antibiotics tested. Identical antibiotic resistance patterns of the isolates may indicate that they share a common mode of developing antibiotic resistance. Furthermore, the multiple antibiotic resistance indexing showed that all strains tested originated from high risk contamination. Plasmid profile analysis by agarose gel electrophoresis showed the presence of small plasmids in 12 (7 non-O1 and 5 O1 serotypes) with sizes ranging 1.3-4.6 MDa. The CT gene was detected in all clinical isolates but was present in only 14 (6 O1 serotype and 8 non-O1 serotype) isolates from environmental waters. The genetic relatedness of the clinical and environmental Vibrio cholerae O1 and non-O1 strains was investigated by RAPD fingerprinting with four primers. The four primers generated polymorphisms in all 31 strains of Vibrio cholerae tested, producing bands ranging from < 250 to 4500 bp. The RAPD profiles revealed a wide variability and no correlation with the source of isolation. This study provides evidence that Vibrio cholerae O1 and non-O1 have significant public health implications.
    Matched MeSH terms: Plasmids
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