MyMedR

Antibiotic resistance and conjugative R plasmids in clinical isolates of Enterobacteriaceae in Peninsular Malaysia

Koh CL

Trans R Soc Trop Med Hyg, 1986;80(1):158-61.

Twenty-five strains of enterobacteria, isolated from man in Peninsular Malaysia and consisting of seven Enterobacter spp., five Escherichia coli, five Salmonella spp., four Klebsiella spp., two Shigella spp., one Proteus sp. and and one Providencia sp., were tested for antibiotic resistance and conjugative R plasmids. They were all sensitive to nalidixic acid and resistant to at least three antibiotics. The number of resistances ranged from 3 to 11 antibiotics, including cefoperazone and sisomicin (two) newly released antibiotics), in addition to common drugs of current use. Of the 25 isolates, 19 (76%) conjugally transferred, at varied frequencies, at least two resistance determinants. Results from equilibrium density gradient centrifugation, agarose gel electrophoresis and transformation experiments provided proof that the transferable resistances were plasmid-mediated. Restriction endonuclease cleavage patterns showed that the plasmids from Proteus strain K005 and Providencia strain K001 may be identical.

HLA-DQ alpha genotype and allele frequencies in Malays, Chinese, and Indians in the Malaysian population

Koh CL, Benjamin DG

Hum. Hered., 1994 May-Jun;44(3):150-5.

PMID: 8039798

The HLA-DQ alpha genotype and allele frequencies in 130 Malays, 125 Chinese, and 137 Indians in the Malaysian population were determined using a commercial HLA-DQ alpha DNA amplification and typing kit which distinguishes 6 alleles (DQA1.1, DQA1.2, DQA1.3, DQA2, DQA3, and DQA4) and 21 possible genotypes at this locus. All 21 genotypes were encountered in the Malay and Indian samples, but DQA1.1,DQA1.3 and DQA2,DQA2 genotypes were absent in the Chinese sample. In all three ethnic groups, the numbers observed for the various DQ alpha genotypes were in accordance with those expected from Hardy-Weinberg equilibrium. The allele frequencies observed in these three groups were significantly different to allow them to be distinguished as distinct populations. For the Malays, Chinese, and Indians, heterozygosity values at this locus were 0.77, 0.77, and 0.83, respectively, and values of the power of discrimination were 0.91, 0.90, and 0.94, respectively. These population data will enable the HLA-DQ alpha locus to be used as a marker in forensic identity testing in Malaysia.

Antimicrobial resistance and conjugative R plasmids in Escherichia coli strains isolated from animals in Peninsular Malaysia

Koh CL, Kok CH

Southeast Asian J. Trop. Med. Public Health, 1984 Mar;15(1):37-43.

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.

Nonconjugative R plasmid-mediated antibiotic resistance in Escherichia coli isolated from animals in Peninsular Malaysia

Koh CL, Kok CH

Southeast Asian J. Trop. Med. Public Health, 1984 Sep;15(3):313-6.

PMID: 6395350

Four of the five veterinary E. coli strains, which were unable to transfer their antibiotic resistance by conjugation, were found to harbour plasmids. Evidence from transformation, agarose gel electrophoresis and curing experiments showed that in strains KE-3, KE-4 and KE-14 a nonconjugative R plasmid carried the gene for resistance to tetracycline. The plasmids in KE-9 were cryptic.

Fulltext R plasmid-borne transferable multiple antibiotic resistance in a clinical isolate of Proteus sp in Peninsular Malaysia

Koh CL, Tay SH

Singapore Med J, 1984 Oct;25(5):300-3.

PMID: 6523137

A clinical isolate of Proteus sp., resistant to ampicillin, carbenicillin, cephaloridine, chloramphenicol, cotrimoxazole, gentamicin,
kanamycin and tetracycline, was examined for the presence of conjugative R plasmids. Results from conjugation, agarose gel
electrophoresis and transformation experiments showed that it harboured a large self-transmissible R plasmid which coded for all
the resistance traits.

Fulltext Knowledge of diabetes mellitus among diabetic and non-diabetic patients in Klinik Kesihatan Seremban

Ding CH, Teng CL, Koh CN

Med J Malaysia, 2006 Oct;61(4):399-404.

PMID: 17243515 MyJurnal

The Malaysian Ministry of Health has undertaken various campaigns on healthy lifestyle and health promotion over the years. The impact of these campaigns has been mixed and not well documented. This cross-sectional study evaluated the knowledge level of patients with and without diabetes in a large urban polyclinic using a 41-item questionnaire. One hundred and forty-nine adults (83 with diabetes, 66 without diabetes) participated in this study. Patients with diabetes had higher overall knowledge scores than those without diabetes (81.8% vs 64.0%, p < 0.001). While the overall knowledge of patients without diabetes appeared to be acceptable, several areas of knowledge deficiency were identified in this group--areas that should be filled by the on-going health promotion activities.
Study site: Klinik Kesihatan Seremban, Seremban, Negeri Sembilan, Malaysia

Fulltext Response: Scientific misconduct encountered by APAME journals: insight?

Looi LM, Wong LX, Koh CC

Malays J Pathol, 2016 Apr;38(1):73.

PMID: 27126670

Treatment of chronic urticaria with thyroxine in an euthyroid patient with thyroglobulin and microsomal antibodies

Koh CK, Hew FL, Chiu CL

Ann Acad Med Singap, 2000 Jul;29(4):528-30.

PMID: 11056786

INTRODUCTION: The association of chronic urticaria and thyroid autoimmunity is not well recognised and the potential use of thyroxine in the treatment of chronic urticaria in patients with thyroid autoimmunity is even less well known.

CLINICAL PICTURE: We report a case of chronic urticaria in an euthyroid patient with evidence of significantly elevated levels of thyroglobulin and microsomal antibodies.

TREATMENT AND OUTCOME: Treatment with thyroxine has brought about clinical remission of the chronic urticaria but no change in the thyroid antibody levels could be demonstrated.

CONCLUSION: Patients with chronic urticaria should be screened for evidence of thyroid autoimmunity. A closely monitored trial of thyroxine therapy for those who have thyroid autoimmunity can be rewarding.

Fulltext Outpatient procedures for cervical dysplasia: a 3 year review of laser vaporisation and LEEP

Lee KE, Koh CF, Watt WF

Med J Malaysia, 1999 Mar;54(1):47-51.

PMID: 10972004

A 3 year retrospective review (1995 to 1997) of 127 patients with cervical dysplasia who underwent Laser Vaporisation of the cervix and LEEP at the Gynaecological Cancer Centre, KK Women's & Children's Hospital, Singapore, was undertaken. Amongst the patients in the Laser Vaporisation group, the mean age was 37.7 years (SD 8.8), the mean operating time was 14.8 minutes (SD 8.5), 63.6% were given prophylactic antibiotics and the mean follow up period was 15.3 months (SD 12.0), whilst in the LEEP group, mean age was 40.3 years (SD 8.4), mean operating time, 11.8 minutes (SD 4.9), prophylactic antibiotic rate, 53.8% and mean follow up period was 19.1 months (SD 9.3). Mild and moderate haemorrhage post procedure were the only complications encountered, 10.2% (5/49) in the Laser group and 3.8% (3/78) in the LEEP group. 98% (48/49) and 97.4% (76/78) of the Laser and LEEP groups, respectively, were free of disease on follow up. None of the 3 patients with persistent or recurrent disease were diagnosed as having invasive cancer. Overall, there were no significant differences in the patient characteristics, histopathology, operating times, follow up period, the use of prophylactic antibiotics, and complications in the 2 groups. The low complication rate, high disease-free rate and the relatively short operating time of Laser Vaporisation and LEEP in our study suggests that, indeed, both the procedures can be done safely and efficiently in the outpatient setting. However the discrepancy between the histology of colposcopically directed biopsy and that of LEEP specimens suggests that colposcopically directed biopsy may not be as accurate as one might believe, and further studies analysing the concordance between colposcopically directed biopsy and LEEP biopsy histologies are needed.

Genetic variation among Malaysian isolates of Salmonella typhi as detected by ribosomal RNA gene restriction patterns

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.

ras gene mutations in Malaysian leukemia patients

Chin IY, Koh CL, Bosco JJ

Acta Haematol., 1992;87(1-2):107-8.

PMID: 1585764

Molecular epidemiology of Malaysian dengue 2 viruses isolated over twenty-five years (1968-1993)

Fong MY, Koh CL, Lam SK

Res. Virol., 1998 Nov-Dec;149(6):457-64.

PMID: 9923022

The limited sequencing approach was used to study the molecular epidemiology of 24 Malaysian dengue 2 viruses which were isolated between 1968 and 1993. The sequences of a 240-nucleotide-long region across the envelope/non-structural 1 protein (E/NS1) gene junction of the isolates were determined and analysed. Alignment and comparison of the nucleotide and deduced amino acid sequences of the isolates revealed that nucleotide changes occurred mostly at the third position of a particular codon and were of the transition (AG, CU) type. Five nucleotide changes resulted in amino acid substitutions. Pairwise comparisons of the nucleotide sequences gave divergence values ranging from 0 to 9.2%. At the amino acid level, the divergence ranged between 0 and 3.8%. Based on the 6% divergence as the cut-off point for genotypic classification, the isolates were grouped into two genotypes, I and II. Comparison of the nucleotide sequences of the Malaysian dengue isolates with those of the dengue viruses of other regions of the world revealed that members of genotypes I and II were closely related to viruses from the Indian Ocean and Western Pacific regions, respectively.

Fulltext Breakpoint cluster region (BCR) gene rearrangement studies in chronic myeloid and acute lymphoblastic leukemias

Chin YM, Bosco JJ, Koh CL

Med J Malaysia, 1992 Jun;47(2):110-3.

PMID: 1494330

Deoxyribonucleic acid (DNA) of twenty chronic myeloid leukemia (CML) and thirty acute lymphoblastic leukemia (ALL) patients were analysed by Southern hybridization. The DNA was digested with BglII and hybridized with a 4.5-kilobase (kb) ph1/bcr-3 DNA probe. All the 20 CML patients showed gene rearrangement within a 5.8-kb segment (the major breakpoint cluster region, M-bcr) of the breakpoint cluster region (bcr) gene of chromosome 22, indicating the presence of the Philadelphia chromosome. M-bcr rearrangement at the bcr gene of chromosome twenty-two was not detected in all the thirty ALL patients (nine adults and twenty-one children) and two normal controls.

Plasmid incidence rate and conjugative chloramphenicol and tetracycline resistance plasmids in Malaysian isolates of Salmonella typhi

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.

Plasmid profiles of Neisseria gonorrhoeae in Peninsular Malaysia

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.

Conjugal transfer of multiple antibiotic resistance from hospital isolates of Klebsiella to Escherichia coli

Koh CL, Lim ME, Wong YH

Southeast Asian J. Trop. Med. Public Health, 1983 Sep;14(3):336-40.

PMID: 6362015

Six independent isolates of Klebsiella from hospital environmental sources in Malaysia were found to be resistant to at least ampicillin, carbenicillin, cefoperazone, chloramphenicol, gentamicin and tetracycline. On the basis of their antibiograms, they were divided into four antibiogroups. They transferred all or part of their multiple antibiotic resistance traits to E. coli by conjugation. The results suggest that these Klebsiella strains harbour self-transmissible R plasmids. The significance of these findings are discussed.

Fulltext Nucleotide and encoded amino acid sequences of the membrane protein precursor and the membrane protein genes of three dengue-2 viruses isolated in Malaysia from patients with dengue haemorrhagic fever, dengue shock syndrome or dengue fever

Samuel S, Koh CL, Pang T, Lam SK

Nucleic Acids Res, 1990 Apr 11;18(7):1905.

PMID: 2336374 DOI: 10.1093/nar/18.7.1905

Fulltext Nucleotide and encoded amino acid sequences of the capsid protein gene of three dengue-2 viruses isolated in Malaysia from patients with dengue haemorrhagic fever, dengue shock syndrome or dengue fever

Samuel S, Koh CL, Pang T, Lam SK

Nucleic Acids Res, 1990 Apr 11;18(7):1904.

PMID: 2336373

Fulltext Cutaneous tuberculosis mimicking cellulitis in an immunosuppressed patient

Chin PW, Koh CK, Wong KT

Singapore Med J, 1999 Jan;40(1):44-5.

PMID: 10361486

A 28-year-old lady suffering from systemic lupus erythomatosus (SLE) with diffuse proliferative glomerulonephritis (DPGN) and who was on oral cyclophosphamide and prednisolone presented with left lower limb 'cellulitis'. The 'cellulitis' of the left lower limb failed to respond to usual antibiotics which prompted evaluation of the clinical diagnosis. The diagnosis is made based on the presence of granulomas, multinucleated giant cells and acid fast bacilli on the skin biopsy.

Fulltext Analysis of ras gene mutations in acute myeloid leukemia by the polymerase chain reaction and oligonucleotide probes

Chin YM, Bosco JJ, Koh CL

Singapore Med J, 1992 Feb;33(1):48-50.

PMID: 1598607

In vitro deoxyribonucleic acid (DNA) amplification by the polymerase chain reaction (PCR) followed by hybridization with oligonucleotide probes were used to study ras gene mutations in acute myeloid leukemia (AML). The DNA of 30 AML patients at presentation of the disease at the University of Malaya Hospital, Kuala Lumpur were screened for ras gene mutations in codons 12, 13 and 61 of the N-ras, K-ras and H-ras genes. Four patients (13.3%) had ras gene mutations. They were all below their early thirties in age. Of the four patients with ras gene mutations, three were M3 and one was M4 according to the French American British (FAB) classification of AML.

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