Displaying publications 1 - 20 of 28 in total

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  1. Baek JY, Kang CI, Kim SH, Ko KS, Chung DR, Peck KR, et al.
    Diagn Microbiol Infect Dis, 2016 Jun;85(2):218-20.
    PMID: 27083121 DOI: 10.1016/j.diagmicrobio.2016.02.022
    Tedizolid phosphate is a second-generation oxazolidinone prodrug that is potential activity against a wide range of Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, penicillin-resistant streptococci, and vancomycin-resistant enterococci. The in vitro activity of tedizolid and other comparator agents against multidrug-resistant (MDR) pneumococci from various Asian countries were evaluated. Of the S. pneumoniae clinical pneumonia isolates collected during 2008 and 2009 from 8 Asian countries (Korea, Taiwan, Thailand, Hong Kong, Vietnam, Malaysia, Philippines, and Sri Lanka), 104 isolates of MDR pneumococci were included in this study. Antimicrobial susceptibility testing for 18 antimicrobial agents was performed by broth microdilution method. Tedizolid was highly active against pneumococci. All isolates tested were inhibited at a tedizolid minimum inhibitory concentration (MIC) value of ≤0.25μg/ml (ranged from ≤0.03μg/ml to 0.25μg/ml). The MIC50 and MIC90 of tedizolid against MDR pneumococci were both 0.12μg/ml, while MIC50 and MIC90 of linezolid were 0.5μg/ml and 1μg/ml, respectively. In addition, tedizolid maintained the activity against S. pneumoniae regardless of the extensively drug-resistant (XDR) phenotype of the isolates. The activity of tedizolid was excellent against all types of MDR pneumococci, exhibiting and maintaining at least 4-fold-greater potency compared to linezolid, regardless of resistance phenotypes to other commonly utilized agents. Tedizolid has the potential to be an agent to treat infections caused by MDR pneumococci in the Asia.
  2. Louizi C, Khan MAA, Faisal K, Chowdhury R, Ghosh P, Hossain F, et al.
    Diagn Microbiol Infect Dis, 2023 Feb;105(2):115862.
    PMID: 36493571 DOI: 10.1016/j.diagmicrobio.2022.115862
    The spread of vector habitats along with increasing human mobility can introduce atypical Leishmania species and hence can challenge existing diagnostic practices for rapid detection of active infection with species outside the narrow target range. Here we assessed the pan-Leishmania detection ability of isothermal recombinase polymerase amplification (RPA) assays targeting 18S rRNA gene, cathepsin L-like cysteine proteinase B (Cpb) gene, and kinetoplast minicircle DNA (kDNA) regions. While the lowest limit of detection of the 18S rRNA-RPA and Cpb-RPA assays were estimated as 12 and 17 standard DNA molecules, respectively, both assays could amplify genomic DNA of 7 pathogenic Leishmania species. Evaluation of 18S rRNA-RPA and our previously developed kDNA-RPA assays on 70 real-time PCR-positive leishmaniasis samples of varying pathologies resulted in sensitivity rates of 35.71% and 88.57%, respectively, while the combined sensitivity was 98.57%. Combinatorial application of 18S rRNA-RPA and kDNA-RPA assays can be recommended for further diagnostic assessments.
  3. Issa R, Mohd Hassan NA, Abdul H, Hashim SH, Seradja VH, Abdul Sani A
    Diagn Microbiol Infect Dis, 2012 Jan;72(1):62-7.
    PMID: 22078904 DOI: 10.1016/j.diagmicrobio.2011.09.021
    A real-time quantitative polymerase chain reaction (qPCR) was developed for detection and discrimination of Mycobacterium tuberculosis (H37Rv and H37Ra) and M. bovis bacillus Calmette-Guérin (BCG) of the Mycobacterium tuberculosis complex (MTBC) from mycobacterial other than tuberculosis (MOTT). It was based on the melting curve (Tm) analysis of the gyrB gene using SYBR(®) Green I detection dye and the LightCycler 1.5 system. The optimal conditions for the assay were 0.25 μmol/L of primers with 3.1 mmol/L of MgCl(2) and 45 cycles of amplification. For M. tuberculosis (H37Rv and H37Ra) and M. bovis BCG of the MTBC, we detected the crossing points (Cp) at cycles of 16.96 ± 0.07, 18.02 ± 0.14, and 18.62 ± 0.09, respectively, while the Tm values were 90.19 ± 0.06 °C, 90.27 ± 0.09 °C, and 89.81 ± 0.04 °C, respectively. The assay was sensitive and rapid with a detection limit of 10 pg of the DNA template within 35 min. In this study, the Tm analysis of the qPCR assay was applied for the detection and discrimination of MTBC from MOTT.
  4. Mohamed Zahidi J, Bee Yong T, Hashim R, Mohd Noor A, Hamzah SH, Ahmad N
    Diagn Microbiol Infect Dis, 2015 Apr;81(4):227-33.
    PMID: 25641125 DOI: 10.1016/j.diagmicrobio.2014.12.012
    Molecular approaches have been investigated to overcome difficulties in identification and differentiation of Brucella spp. using conventional phenotypic methods. In this study, high-resolution melt (HRM) analysis was used for rapid identification and differentiation of members of Brucella genus. A total of 41 Brucella spp. isolates from human brucellosis were subjected to HRM analysis using 4 sets of primers, which identified 40 isolates as Brucella melitensis and 1 as Brucella canis. The technique utilized low DNA concentration and was highly reproducible. The assay is shown to be a useful diagnostic tool, which can rapidly differentiate Brucella up to species level.
  5. Tay ST, Rohani MY, Ho TM, Devi S
    Diagn Microbiol Infect Dis, 2002 Oct;44(2):137-42.
    PMID: 12458119
    In this study, recombinant proteins that encompassed the AD I-AD III regions of 56 kDa immunodominant gene of 2 Orientia tsutsugamushi (OT) serotypes; Gilliam and TA763 were expressed in Escherichia coli. Both recombinant proteins exhibited serologic cross-reactivity with the rabbit antisera against various OT serotypes, as evaluated by enzyme-linked immunosorbent assay (ELISA), but not against other rickettsial species, including Rickettsia typhi, R. prowazekii and TT118 SFG rickettsiae. The feasibility of using the recombinant proteins as a diagnostic reagent was further evaluated by ELISA using sera from blood donors and scrub typhus patients. The results suggested a higher affinity of the antihuman IgM than IgG with both recombinant proteins. The IgM ELISA findings were agreeable with the results of indirect immunoperoxidase (IIP) assay especially with sera of high antibody (1:1600). However, more than one antigen are probably needed for development of an effective assay for serodiagnosis of scrub typhus in endemic areas.
  6. Islam AH, Singh KK, Ismail A
    Diagn Microbiol Infect Dis, 2011 Jan;69(1):38-44.
    PMID: 21146712 DOI: 10.1016/j.diagmicrobio.2010.09.008
    Acinetobacter baumannii is an emerging nosocomial pathogen that is resistant to many types of antibiotics, and hence, a fast, sensitive, specific, and economical test for its rapid diagnosis is needed. Development of such a test requires a specific antigen, and outer membrane proteins (OMPs) are the prime candidates. The goal of this study was to find a specific OMP of A. baumannii and demonstrate the presence of specific IgM, IgA, and IgG against the candidate protein in human serum. OMPs of A. baumannii ATCC 19606 and 16 other clinical isolates of A. baumannii were extracted from an overnight culture grown at 37 °C. Protein profiles were obtained using sodium dodecyl sulfate polyacrylamide gel electrophoresis, and Western blot analysis was performed to detect the presence of IgM, IgA, and IgG against the OMP in host serum. An antigenic 34.4-kDa OMP was uniquely recognized by IgM, IgA, and IgG from patients with A. baumannii infection, and it did not cross-react with sera from patients with other types of infection. The band was also found in the other 16 A. baumannii isolates. This 34.4-kDa OMP is a prime candidate for development of a diagnostic test for the presence of A. baumannii.
  7. Aziah I, Ravichandran M, Ismail A
    Diagn Microbiol Infect Dis, 2007 Dec;59(4):373-7.
    PMID: 17964105
    Conventional polymerase chain reaction (PCR) testing requires many pipetting steps and has to be transported and stored in cold chain. To overcome these limitations, we designed a ready-to-use PCR test for Salmonella typhi using PCR reagents, primers against the ST50 gene of S. typhi, a built-in internal amplification control (IAC), and gel loading dye mixed and freeze-dried in a single tube. The 2-step dry-reagent-based assay was used to amplify a 1238-bp target gene and an 810-bp IAC gene from 73 BACTEC blood culture broths (33 true positives for S. typhi and 40 true negatives for non-S. typhi). The sensitivity, specificity, positive predictive value, and negative predictive value of the PCR assay were 87.9%, 100%, 100%, and 90.9%, respectively. We suggest that this rapid 2-step PCR test could be used for the rapid diagnosis of typhoid fever.
  8. Biedenbach DJ, Lewis MT, Jones RN
    Diagn Microbiol Infect Dis, 1999 Dec;35(4):277-83.
    PMID: 10668586
    The degree of activity of several beta-lactam antimicrobial agents was assessed in Malaysia (four medical centers) and Singapore (two medical centers) tested against 570 clinical isolates. The organisms were tested locally by the Etest (AB BIODISK, Solna, Sweden) method, validated by concurrent use of quality assurance strains (94.1% accurate performance overall). Ten groups of bacteria were tested against cefepime, cefpirome, ceftazidime, ceftriaxone, piperacillin/tazobactam, oxacillin, and imipenem. Among the tested Escherichia coli and Klebsiella spp., the occurrence of extended spectrum beta-lactamase-producing phenotypes was 5.6-7.0% and 36.7-38.0%, respectively. These strains remained most susceptible (97.5-100.0%) to cefepime and imipenem. Ceftazidime-resistant Enterobacter spp. (21.4% resistant), Citrobacter spp. (15.0%), indole-positive Proteus spp. (6.0%), and Serratia spp. (9.7%) were not resistant to cefepime, and only one strain was resistant to imipenem. Imipenem was generally most potent against non-fermentative Gram-negative bacilli such as Acinetobacter spp. and Pseudomonas aeruginosa. All tested beta-lactams were active against the oxacillin-susceptible staphylococci, except ceftazidime (MIC90, 12 micrograms/mL; 63.2-84.8% susceptibility rates). Overall spectrums of activity (rank by % resistance) favored imipenem (3.5%) > cefepime (7.7%) > cefpirome (8.9%) > piperacillin/tazobactam (13.2%) > ceftriaxone (14.7%) > ceftazidime (16.9%). No significant differences in resistance patterns were noted between monitored nations, and these results indicate emerging, elevated rates of resistance versus the studied broad-spectrum beta-lactams in Malaysia and Singapore. Results provide benchmark data for future studies using quantitative methods to determine antimicrobial resistance in these geographic areas.
  9. Afzan MY, Sivanandam S, Kumar GS
    Diagn Microbiol Infect Dis, 2010 Oct;68(2):159-62.
    PMID: 20846588 DOI: 10.1016/j.diagmicrobio.2010.06.005
    Trichomonas vaginalis, a flagellate protozoan parasite commonly found in the human genitourinary tract, is transmitted primarily by sexual intercourse. Diagnosis is usually by in vitro culture method and staining with Giemsa stain. There are laboratories that use Gram stain as well. We compared the use of modified Field's (MF), Giemsa, and Gram stains on 2 axenic and xenic isolates of T. vaginalis, respectively. Three smears from every sediment of spun cultures of all 4 isolates were stained, respectively, with each of the stains. We showed that MF staining, apart from being a rapid stain (20 s), confers sharper staining contrast, which differentiates the nucleus and the cytoplasm of the organism when compared to Giemsa and Gram staining especially on parasites from spiked urine samples. The alternative staining procedure offers in a diagnostic setting a rapid stain that can easily visualize the parasite with sharp contrasting characteristics between organelles especially the nucleus and cytoplasm. Vacuoles are more clearly visible in parasites stained with MF than when stained with Giemsa.
  10. Ong EB, Anthony AA, Ismail A, Ismail A, Lim TS
    Diagn Microbiol Infect Dis, 2013 Sep;77(1):87-9.
    PMID: 23790417 DOI: 10.1016/j.diagmicrobio.2013.05.010
    The hemolysin (HlyE) protein of Salmonella enterica serovar Typhi was reported to be antigenic. This work describes the cloning, expression, and purification of a hexahistidine-tagged HlyE protein under native conditions. Immunoblot analysis and a competitive enzyme-linked immunosorbent assay using sera from typhoid patients showed the presence of HlyE-specific antibodies in circulation.
  11. Vola A, Tamarozzi F, Noordin R, Yunus MH, Khanbabaie S, De Silvestri A, et al.
    Diagn Microbiol Infect Dis, 2018 Sep;92(1):31-33.
    PMID: 29776711 DOI: 10.1016/j.diagmicrobio.2018.04.007
    Rapid diagnostic tests for cystic echinococcosis (CE) are convenient to support ultrasound diagnosis in uncertain cases, especially in resource-limited settings. We found comparable diagnostic performances of the experimental Hyd Rapid Test and the commercial VIRapid HYDATIDOSIS Test, used in our diagnostic laboratory, using samples from well-characterized hepatic CE cases.
  12. Sam IC, Kahar-Bador M, Chan YF, Loong SK, Mohd Nor Ghazali F
    Diagn Microbiol Infect Dis, 2008 Dec;62(4):437-9.
    PMID: 18842374 DOI: 10.1016/j.diagmicrobio.2008.07.016
    The 1st 9 clinical isolates of multisensitive community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) from Malaysia carry SCCmec type IV and predominantly cause skin and soft-tissue infections. Seven were classified as nosocomially acquired. There was considerable clonal diversity, with both pandemic and novel multilocus sequence types detected. CA-MRSA rates appear to be increasing in our hospital, warranting close surveillance.
  13. Salleh FM, Al-Mekhlafi AM, Nordin A, Yasin 'M, Al-Mekhlafi HM, Moktar N
    Diagn Microbiol Infect Dis, 2011 Jan;69(1):82-5.
    PMID: 21146718 DOI: 10.1016/j.diagmicrobio.2010.08.028
    This study was conducted to evaluate the modification of the usual Gram-chromotrope staining technique developed in-house known as Gram-chromotrope Kinyoun (GCK) in comparison with the Weber Modified Trichrome (WMT) staining technique; as the reference technique. Two hundred and ninety fecal specimens received by the Microbiology Diagnostic Laboratory of Hospital Universiti Kebangsaan Malaysia were examined for the presence of microsporidial spores. The sensitivity and specificity of GCK compared to the reference technique were 98% and 98.3%, respectively. The positive and negative predictive values were 92.5% and 99.6%, respectively. The agreement between the reference technique and the GCK staining technique was statistically significant by Kappa statistics (K = 0.941, P < 0.001). It is concluded that the GCK staining technique has high sensitivity and specificity in the detection of microsporidial spores in fecal specimens. Hence, it is recommended to be used in the diagnosis of intestinal microsporidiosis.
  14. 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.
  15. Lee SH, Chong CE, Lim BS, Chai SJ, Sam KK, Mohamed R, et al.
    Diagn Microbiol Infect Dis, 2007 Jul;58(3):263-70.
    PMID: 17350202
    Burkholderia pseudomallei is a Gram-negative saprophytic soil bacterium, which is the etiologic agent of melioidosis, a severe and fatal infectious disease occurring in human and animals. Distinct clinical and animal isolates have been shown to exhibit differences in phenotypic trait such as growth rate, colony morphology, antimicrobial resistance, and virulence. This study was carried out to gain insight into the intrinsic differences between 4 clinical and 6 animal B. pseudomallei isolates from Malaysia. The 16S rRNA-encoding genes from these 10 isolates of B. pseudomallei were sequenced to confirm the identity of these isolates along with the avirulent Burkholderia thailandensis. The nucleotide sequences indicated that the 16S rRNA-encoding genes among the 10 B. pseudomallei isolates were identical to each other. However, the nucleotide sequence differences in the 16S rRNA-encoding genes appeared to be B. pseudomallei and B. thailandensis specific. The growth rate of all B. pseudomallei isolates was determined by generating growth curves at 37 degrees C for 72 h. The isolates were found to differ in growth rates with doubling time varying from 1.5 to 2.3 h. In addition, the B. pseudomallei isolates exhibited considerable variation in colony morphology when grown on Ashdown media, brain-heart infusion agar, and Luria-Bertani agar over 9 days of observation. Antimicrobial susceptibility tests indicated that 80% of the isolates examined were Amp(R) Cb(R) Kn(R) Gm(R) Chl(S) Te(S). Virulence of the B. pseudomallei clinical and animal isolates was evaluated in B. pseudomallei-susceptible BALB/c mice. Most of the clinical isolates were highly virulent. However, virulence did not correlate with isolate origin since 2 of the animal isolates were also highly virulent.
  16. Gunasegar S, Neela VK
    Diagn Microbiol Infect Dis, 2021 Jul;100(3):115369.
    PMID: 33845305 DOI: 10.1016/j.diagmicrobio.2021.115369
    Loop-mediated isothermal amplification (LAMP) test is widely used in molecular diagnostics as a point-of-care technique alternative to traditional PCR especially in resource-limited countries. LAMP has been recently used to diagnose leptospirosis. Therefore, we undertook a systematic review and meta-analysis to compare the accuracy of LAMP with PCR in the diagnosis of leptospirosis. Sixty-one studies were extracted from three international databases and analyzed throughout using the PRISMA guideline. The pooled sensitivity of LAMP and PCR technique was 0.80 (95% CI: 0.58-0.90) and 0.54 (95% CI: 0.35-0.67) respectively indicating that LAMP is more sensitive than PCR. The Q* value of LAMP and PCR-based technique is 274.61 and 397.95, respectively. Among the analyzed studies, significant heterogeneity was observed where I2 is 90.90% for LAMP-based and 86.18% for PCR-based. Our study suggests that LAMP has better diagnostic accuracy than PCR. However, future work should be carried out to reduce heterogeneity as well as to improve and develop effective intervention strategies.
  17. Radu S, Toosa H, Rahim RA, Reezal A, Ahmad M, Hamid AN, et al.
    Diagn Microbiol Infect Dis, 2001 Mar;39(3):145-53.
    PMID: 11337180
    Enterococcus species isolated from poultry sources were characterized for their resistance to antibiotics, plasmid content, presence of van genes and their diversity by randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). The results showed that all isolates were multi-resistance to the antibiotics tested. Ampicillin (15/70) followed by chloramphenicol (37/70) were the most active antibiotics tested against the Enterococcus spp. isolates, while the overall resistant rates against the other antibiotics were between 64.3% to 100%. All vancomycin-resistant E. faecalis, E. durans, E. hirae and E. faecium isolates tested by the disk diffusion assay were positive in PCR detection for presence of vanA gene. All E. casseliflavus isolates were positive for vanC2/C3 gene. However, none of the Enterococcus spp. isolates were positive for vanB and vanC1 genes. Plasmids ranging in sizes between 1.1 to ca. 35.8 MDa were detected in 38/70 of the Enterococcus isolates. When the genetic relationship among all isolates of the individual species were tested by RAPD-PCR, genetic differences detected suggested a high genetic polymorphisms of isolates in each individual species. Our results indicates that further epidemiological studies are necessary to elucidate the role of food animals as reservoir of VRE and the public health significance of infections caused by Enterococcus spp.
  18. Chang CH, Riazi M, Yunus MH, Osman S, Noordin R
    Diagn Microbiol Infect Dis, 2014 Dec;80(4):278-81.
    PMID: 25241641 DOI: 10.1016/j.diagmicrobio.2014.08.012
    This study evaluated 2 rapid leptospirosis serological tests, Leptorapide® (Linnodee, Northern Ireland) and VISITECT®-LEPTO (Omega Diagnostics, Scotland, UK), which are commonly used in Malaysia. A total of 183 samples comprised 113 sera from leptospirosis patients, and 70 sera from other infections and healthy controls were used. The leptospirosis sera were grouped into 2 serum panels, i.e., Group I (MAT+, PCR+) and Group II (MAT+). When inconclusive results were interpreted as positives, both tests showed lower diagnostic sensitivities (≤ 34%) with Group I sera, as compared to Group II sera (Leptorapide®, 93%; VISITECT®-LEPTO, 40%). When inconclusive results were interpreted as negatives, the 2 tests showed ~20% sensitivity with both serum panels. The diagnostic specificity of VISITECT®-LEPTO (94%) was superior to Leptorapide® (69%). Since both tests had misdiagnosed a large proportion of Group I patients and showed many inconclusive results among Group II patients, they have limited diagnostic value in detecting acute leptospirosis.
  19. Chenthamarakshan V, Vadivelu J, Puthucheary SD
    Diagn Microbiol Infect Dis, 2001 Jan;39(1):1-7.
    PMID: 11173184
    IgM and IgG based ELISA systems were developed using the culture filtrate antigen (CFA) of Burkholderia pseudomallei. The assays were evaluated using 95 sera from 66 septicemic cases and 47 sera from 20 cases with localized melioidosis. In addition 65 sera from culture negative cases that were also serologically negative for other endemic infections clinically suspected of melioidosis were included. These were compared with sera from 260 non-melioidosis cases, 169 sera from individuals with high risk of acquiring the infection and 48 sera from healthy controls. The IgG-ELISA was 96% sensitive and 94% specific. All sera from cases with septicemic and localized infections and 61 of 63 sera from clinically suspected melioidosis cases were positive for IgG antibody. The geometric mean titre index (GMTI) values of IgG antibody in melioidosis cases were significantly higher (p < 0.0005) compared to that of healthy subjects, high risk group and subjects with non-melioidosis infections. The sensitivity and specificity of IgM ELISA was 74 and 99% respectively. The GMTI value of IgM antibody in the sera of melioidosis cases was significantly higher as compared to that of non-melioidosis disease controls (p < or = 0.001). These results demonstrate that the detection of IgG is a better indicator of the disease in the diagnosis of melioidosis.
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