Displaying publications 21 - 40 of 47 in total

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  1. Cheong YM, Jegathesan M, Singh M, Wong S, Ong L
    Malays J Pathol, 1985 Aug;7:51-2.
    PMID: 3939616
  2. Cheong YM, Joseph PG, Koay AS
    PMID: 3477872
    The current drugs recommended for treatment of melioidosis are tetracycline, chloramphenicol and cotrimoxazole. Unfortunately these drugs are not the drug of choice in an acutely ill patient with septicaemia prior to the availability of laboratory results. With the discovery of the new cephalosporins which have a broad spectrum of activity clinicians are using them either alone or in combination with other antibiotics in such critical situations. Hence, an in-vitro study was carried out on the susceptibility of 41 strains of P. pseudomallei isolated in Malaysia, to these new cephalosporins and a new quinolone. The results showed that all the cephalosporins tested had some activity on the strains tested, with ceftazidime being the most active drug. Pefloxacin had very poor activity. However, further clinical studies are required to determine the duration, dosage and in-vivo activity of the antibiotics.
  3. Ngeow YF, Ramachandran S, Cheong YM
    Sex Transm Dis, 1991 7 1;18(3):192-4.
    PMID: 1948519
    Between January and August, 1989, 36 men and 28 women with uncomplicated lower genital tract infections by Neisseria gonorrhoeae were given single intramuscular injections of sulbactam (500 mg)/ampicillin (1000 mg) together with 1 g oral probenecid. Cure rates that were obtained were 100% for women, 97.2% for men, 100% for patients with penicillinase-producing Neisseria gonorrhoeae (PPNG), and 98.4% for patients with non-PPNG. No serious side effects were encountered, and patient acceptance of the drug was good. A high proportion of patients had concurrent chlamydial infection. Sulbactam/ampicillin was found to be effective against gonococcal urethritis and cervicitis by both PPNG and non-PPNG but have little effect on concomitant chlamydial infections, especially in women.
  4. Lim VK, Cheong YM, Suleiman AB
    Singapore Med J, 1993 Dec;34(6):525-8.
    PMID: 8153716
    A prospective survey of antibiotic prescribing patterns in six Ministry of Health general hospitals in Malaysia was undertaken. Information on antibiotic prescriptions including the types of antibiotics used and the purposes for prescription was obtained through the use of questionnaires. A total of 1,918 antibiotic prescriptions were available for analysis. About two-thirds of prescriptions were for therapeutic purposes. The most common infections treated were lower respiratory infection (31%), followed by skin and soft tissue infection (17%), and urinary tract infection (8%). Only 20% of the therapeutic prescriptions were based on microbiological test results. Prophylactic prescriptions were issued for a variety of indications, the most common being toilet and suture of wounds. Only 5% of prophylactic prescriptions were of less than 3 days duration. There was great diversity in antibiotics and antibiotic regimens employed. It was evident that there was a lack of compliance with guidelines on antibiotic use issued by the Ministry of Health.
  5. Cheong YM, Wong WK, Ngeow YF
    Singapore Med J, 1993 Aug;34(4):352-3.
    PMID: 8266214
    A first case of Chlamydia pneumoniae pneumonia in Malaysia is reported. The diagnosis was made by a significant change in C. pneumoniae antibody titre. The infection responded well to a course of erythromycin.
  6. 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.
  7. Ho TM, Shara S, Koay AS, Cheong YM
    J Med Entomol, 1992 Jul;29(4):611-3.
    PMID: 1495069
    A dot-immunobinding assay (DIBA) was compared with a direct fluorescent antibody technique (DFAT) for the detection of Rickettsia tsutsugamushi infection in Leptotrombidium fletcheri (Womersley & Heaslip). Laboratory colonies of infected and noninfected chiggers were examined. The relative proportions of positive, negative, and indeterminate results were significantly different between DIBA and DFAT for infected but not for noninfected chiggers. DIBA was more sensitive and had a better negative predictive value and a lower false negative percentage than DFAT. It was concluded that DIBA is a suitable alternative to DFAT for detecting scrub typhus infection in chiggers.
  8. Cheong YM, Lim VK, Jegathesan M, Suleiman AB
    Med J Malaysia, 1994 Dec;49(4):317-26.
    PMID: 7674966
    Knowledge of local antimicrobial resistance patterns of bacteria is a valuable guide to empirical antimicrobial therapy. This paper reports the resistance patterns of more than 36,000 bacteria isolated between August 1991 and July 1992 in six Malaysian hospitals and discusses the implications of the results. A customized menu driven software programme was developed to analyse the results. Generally, resistance to the commonly used antibiotics like ampicillin, cloxacillin, cephalosporins, gentamicin, cotrimoxazole and tetracycline was high. Some differences in resistance rate amongst the six hospitals were also noted. Continuous surveillance of antimicrobial resistance in hospitals is encouraged for the effective control of the emergence of antimicrobial resistance.
  9. Cheong YM, Ng YP, Chin CS, Thambu J
    Med J Malaysia, 1992 Mar;47(1):44-50.
    PMID: 1387449
    Vaginal discharge is a common complaint of women attending gynaecological clinics. The purpose of this study was to compare the occurrence of commonly implicated microorganisms in vaginal discharge amongst women with or without the complaint, attending a gynaecological and family planning clinic. The association of Gardnerella vaginalis with bacterial vaginosis was also studied. It was found that there were no significant differences between the cases and controls in the isolation rate of Gardnerella vaginalis, Torulopsis glabrata, Ureaplasma urealyticum, Mycoplasma ssp and Group B streptococcus (p greater than 0.05). Only the isolation rate of Candida albicans was significantly higher in the cases than controls (p less than 0.01). However, there was a significant association of G. vaginalis with bacterial vaginosis.
  10. Koay AS, Jegathesan M, Rohani MY, Cheong YM
    PMID: 9322288
    Strains of Salmonella typhi implicated in two separate cases of laboratory acquired infection from patients and the medical laboratory technologists who processed the patients' samples were analysed by pulsed-field gel electrophoresis. Although all four isolates were of bacteriophage type E1, PFGE was able to demonstrate that the strains responsible for the two laboratory acquired cases were not genetically related. The PFGE patterns of the isolates from the MLTs were found to be identical to those of the corresponding patients after digestion with restriction enzyme AvrII. This provided genetic as well as epidemiological evidence for the source of the laboratory acquired infections.
  11. Koay AS, Tay ST, Cheong YM, Yasin RM
    PMID: 8629074
    An IgM dot-immunobinding assay (IgM-DIA) was developed for the diagnosis of scrub typhus infection. The whole cell antigens of Karp, Kato and Gilliam strains of Rickettsia tsutsugamushi were immobilized onto nitrocellulose paper and reacted with patients sera. The presence of IgM R. tsutsugamushi specific antibody in the patient sera could be detected by the observation of a visible brown dot on the nitrocellulose paper. The IgM-DIA has a sensitivity of 90.4% and specificity of 81.4% as compared to the indirect immunoperoxidase test. The IgM-DIA is rapid, simple, cost-effective, does not require microscope or incubator. It is recommended as a rapid screening test for the diagnosis of scrub typhus infection in the field or rural area within the hyperendemic region.
  12. Zainah S, Cheong YM, Sinniah M, Gan AT, Akbal K
    Med J Malaysia, 1991 Sep;46(3):274-82.
    PMID: 1839925
    The microbial aetiology of genital ulcers was studied in 249 patients (241 men and 8 women) attending a Sexually Transmitted Disease Clinic in Kuala Lumpur, Malaysia. Herpes simplex virus type 2 was isolated in 48 (19.2%) patients, Haemophilus ducreyi from 22 (8.8%), Neisseria gonorrhoeae from seven (2.8%) and Chlamydia trachomatis from four (1.6%). Syphilis was diagnosed in 18 (7.2%) patients on the basis of dark field microscopy. Two (0.8%) patients were found to have both chancroid and syphilis and one (0.5%) had both gonorrhoea and syphilis. No organism was isolated in the remaining 151 (61.5%) patients. Overall, the accuracy of clinical diagnosis was 58% for single infection, 67% for herpes, 63% for syphilis, 47% for chancroid and 0% for lymphogranuloma venereum. Therefore, our study confirms the need for laboratory tests to diagnose accurately the aetiology of genital ulcer disease.
  13. Lachumanan R, Devi S, Cheong YM, Rodda SJ, Pang T
    Infect Immun, 1993 Oct;61(10):4527-31.
    PMID: 7691753
    Binding studies of 160 overlapping, synthetic octapeptides from the hydrophilic regions of the Sta58 major outer membrane protein of Rickettsia tsutsugamushi with sera from patients with scrub typhus revealed 15 immunodominant peptides which are recognized by all the sera tested. Further analysis of the specificity of peptide binding with five of these peptides indicated that the peptides showed significantly stronger binding to scrub typhus patients' sera than they did to sera from patients with other febrile illnesses common in the region, i.e., malaria, dengue fever, typhoid fever, and leptospirosis. The main antibody class binding to these peptides appears to be immunoglobulin M, and there appears to be little correlation between reactivity with peptides and antibody titers measured by the indirect immunoperoxidase test.
  14. 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.
  15. Thong KL, Cheong YM, Puthucheary S, Koh CL, Pang T
    J Clin Microbiol, 1994 May;32(5):1135-41.
    PMID: 7914202
    Pulsed-field gel electrophoresis (PFGE) was used to compare and analyze 158 isolates of Salmonella typhi from five well-defined outbreaks of typhoid fever in Malaysia and also isolates involved in sporadic cases of typhoid fever occurring during the same period. Digestion of chromosomal DNAs from these S. typhi isolates with the restriction endonucleases XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3') and then PFGE produced restriction endonuclease analysis (REA) patterns consisting of 11 to 24 DNA fragments ranging in size from 20 to 630 kbp. Analysis of the REA patterns generated by PFGE after digestion with XbaI and SpeI indicated that the S. typhi isolates obtained from sporadic cases of infection were much more heterogeneous (at least 13 different REA patterns were detected; Dice coefficient, between 0.73 and 1.0) than those obtained during outbreaks of typhoid fever. The clonal nature and the close genetic identities of isolates from outbreaks in Alor Setar, Penang, Kota Kinabalu, Johor Bahru, and Kota Bahru were suggested by the fact that only a limited number of REA patterns, which mostly differed by only a single band, were detected (one to four patterns; Dice coefficient, between 0.82 and 1.0), although a different pattern was associated with each of these outbreaks. Comparison of REA patterns with ribotyping for 18 S. typhi isolates involved in sporadic cases of infection showed a good correlation, in that 72% of the isolates were in the same group. There was no clear correlation of phage types with a specific REA pattern. We conclude that PFGE of s. typhi chromosomal DNA digested with infrequently cutting restriction endonucleases is a useful method for comparing and differentiating S. typhi isolates for epidemiological purposes.
  16. Cheng HJ, Ee R, Cheong YM, Tan WS, Yin WF, Chan KG
    Sensors (Basel), 2014;14(7):12511-22.
    PMID: 25019635 DOI: 10.3390/s140712511
    A multidrug-resistant clinical bacteria strain GB11 was isolated from a wound swab on the leg of a patient. Identity of stain GB11 as Pseudomonas aeruginosa was validated by using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Detection of the production of signaling molecules, N-acylhomoserine lactones (AHLs), was conducted using three different bacterial biosensors. A total of four different AHLs were found to be produced by strain GB11, namely N-butyryl homoserine lactone (C4-HSL), N-hexanoylhomoserine lactone (C6-HSL), N-octanoyl homoserine lactone (C8-HSL) and N-3-oxo-dodecanoylhomoserine lactone (3-oxo-C12-HSL) using high resolution liquid chromatography tandem mass spectrometry (LC-MS/MS). Of these detected AHLs, 3-oxo-C12-HSL was found to be the most abundant AHL produced by P. aeruginosa GB11.
  17. Yu CY, Ang GY, Cheng HJ, Cheong YM, Yin WF, Chan KG
    Genom Data, 2016 Mar;7:185-6.
    PMID: 26981402 DOI: 10.1016/j.gdata.2015.12.024
    Chryseobacterium indologenes is an emerging pathogen which poses a threat in clinical healthcare setting due to its multidrug-resistant phenotype and its common association with nosocomial infections. Here, we report the draft genome of a multidrug-resistant C. indologenes CI_885 isolated in 2014 from Malaysia. The 908,704-kb genome harbors a repertoire of putative antibiotic resistance determinants which may elucidate the molecular basis and underlying mechanisms of its resistant to various classes of antibiotics. The genome sequence has been deposited in DDBJ/EMBL/GenBank under the accession number LJOD00000000.
  18. Dhanoa A, Rajasekaram G, Lean SS, Cheong YM, Thong KL
    J Pathog, 2015;2015:789265.
    PMID: 26819759 DOI: 10.1155/2015/789265
    Introduction. Acinetobacter calcoaceticus-baumannii complex (ACB complex) is a leading opportunistic pathogen in intensive care units (ICUs). Effective control of spread requires understanding of its epidemiological relatedness. This study aims to determine the genetic relatedness and antibiotic susceptibilities of ACB complex in an ICU in Malaysia. Methodology. Pulsed field gel electrophoresis (PFGE), E-test, and disk diffusion were used for isolates characterization. Results. During the study period (December 2011 to June 2012), 1023 patients were admitted to the ICU and 44 ACB complex (blood, n = 21, and blind bronchial aspirates, n = 23) were recovered from 38 ICU patients. Six isolates were from non-ICU patients. Of the 44 ICU isolates, 88.6% exhibited multidrug-resistant (MDR) patterns. There was high degree of resistance, with minimum inhibitory concentration90 (MIC90) of >32 μg/mL for carbapenems and ≥256 μg/mL for amikacin, ampicillin/sulbactam, and cefoperazone/sulbactam. Isolates from the main PFGE cluster were highly resistant. There was evidence of dissemination in non-ICU wards. Conclusion. High number of clonally related MDR ACB complex was found. While the ICU is a likely reservoir facilitating transmission, importation from other wards may be important contributor. Early identification of strain relatedness and implementation of infection control measures are necessary to prevent further spread.
  19. Chia YC, Lim SH, Wang SJ, Cheong YM, Denaro J, Hettiarachchi J
    Headache, 2003 Oct;43(9):984-90.
    PMID: 14511275
    BACKGROUND/OBJECTIVE: Nonsteroidal anti-inflammatory drugs continue to be one of the most widely used therapies for migraine, but their efficacy in treating moderate to severe migraine headache has not been well documented. In contrast, the efficacy of triptans in this group of patients is well documented, although no systematic research is available that evaluates the effectiveness of switching to a triptan in patients who respond poorly to nonsteroidal anti-inflammatory drugs.

    METHODS: One hundred thirteen patients who met International Headache Society criteria for migraine and who did not experience satisfactory response to nonsteroidal anti-inflammatory drugs, received open-label treatment with a 40-mg dose of eletriptan for one migraine attack. Efficacy assessments were made at 1, 2, 4, and 24 hours postdose and consisted of headache and pain-free response rates, absence of associated symptoms, and functional response. Global ratings of treatment effectiveness and preference were obtained at 24 hours.

    RESULTS: The pain-free response rate at 2 hours postdose was 25% and at 4 hours postdose, 55%; the headache response rate at 2 hours was 66% and at 4 hours, 87%. At 2 hours postdose, relief of baseline associated symptoms was achieved by 41% of patients with nausea compared to 82% of patients at 4 hours; for patients with phonophobia, 67% were relieved at 2 hours and 93% at 4 hours, and for patients with photophobia, 70% were relieved at 2 hours and 91% at 4 hours. Functional response was achieved by 70% of patients by 2 hours postdose. The high level of acute response was maintained over 24 hours, with only 24% of patients experiencing a headache recurrence and only 10% using rescue medication. At 24 hours postdose, 74% of patients rated eletriptan as preferable to any previous treatment for migraine. The most frequent reasons cited for this treatment preference were faster headache improvement (83%) and functional response (78%). Overall, eletriptan was well tolerated; most adverse events were transient and mild to moderate in severity. No serious adverse events were reported.

    CONCLUSION: Results of this open-label trial found the 40-mg dose of eletriptan to have a high degree of efficacy and tolerability among patients who responded poorly to nonsteroidal anti-inflammatory drugs.

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