1.Comparison of susceptibility test methods to detect penicillin susceptibility in Streptococcus pneumoniae isolates.
Mohd Desa Mohd Nasir ; Navaratnam Parasakthi
The Malaysian journal of pathology 2004;26(1):29-33
The increasing prevalence of penicillin-resistant Streptococuus pneumoniae urges for fast and accurate susceptibility testing methods. This study evaluated the comparability of three commonly used techniques; disk diffusion, E-test and agar dilution, to detect penicillin susceptibility in clinical isolates of S. pneumoniae. Fifty pneumococcal isolates, obtained from patients at the University of Malaya Medical Centre, were selected to include both penicillin-susceptible strains and those that had decreased susceptibility (resistant and intermediate) to penicillin. The minimum inhibitory concentration (MIC) values of penicillin to serve as the reference was determined by the agar dilution method in which, based on the MIC breakpoints recommended by the National Committee for Clinical Laboratory Standards (NCCLS), 27 strains had decreased susceptibility to penicillin with 17 strains resistant and 10 intermediate. Comparing to the agar dilution method, oxacillin disk diffusion test detected all strains with decreased penicillin susceptibility as such while E-test showed a close agreement of susceptibility (92%) of the isolates to penicillin. This confirmed that oxacillin is a good screening test for S. pneumoniae isolates with decreased susceptibility to penicillin while E-test is very reliable for rapid and accurate detection of penicillin susceptibility.
Penicillin
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Streptococcus pneumoniae
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Dilution
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Upper case ee
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Clinical
2.Prevalence of Escherichia Coli O157:H7 and Enterobacteriaceae on Hands of Workers in Halal Cattle Abattoirs in Peninsular Malaysia
Shamsul Bahri Mohd Tamrin ; Adamu Muhammad Tukur ; Mohd Desa Mohd Nasir ; Khairani-Bejo Siti
Malaysian Journal of Medical Sciences 2016;23(5):65-71
Background: Several occupational diseases of multiple origins are encountered among
abattoir workers. Presence of indicator microorganisms (coliforms) on hands of workers can be
used a gauge for hygienic practices.
Methods: A cross-sectional study was performed to assess the prevalence of E.coli
and enterobacteriaceae among Halal abattoir workers in some government halal abattoirs of
Malaysia. A total of one hundred and sixty-five hand swab samples were collected from workers
of Halal abattoirs in Malaysia. The samples were subjected to microbiological analysis for
characterisation and serotyping.
Results: The results have shown that no Escherichia coli O157:H7 was isolated on
the hands of abattoir workers before and after work. However, a total prevalence of 9.7% was
recorded for all samples during work. For non-O157:H7, total prevalence of 33.3% during work
and 13% after work were obtained. High prevalence was recorded in sample taken during work
from Tampin, Jasin and Kemaman (100% each) while low prevalence where observed in Shah
Alam, Banting and Ipoh (20% each).
Conclusions: Based on the findings the hygienic practices of hand washing among the
workers in few locations was found to be low especially after work.
3.Pneumococcal replicative state in relation to its adherence capacity to A549-cell line: A preliminary in vitro analysis
Mohd Nasir Mohd Desa ; Navaratnam Parasakthi ; Shamala Devi Sekaran ; Jamunarani Vadivelu
Malaysian Journal of Microbiology 2011;7(2):107-110
This study was to compare the replication capacity of pneumococcal isolates (serotypes 1, 7F, 19F and 23F) with their adherence pattern to monolayer cells (A549). For standardization purposes, all isolates showed a normal growth curve in both bacteriological (THB + 0.5% yeast extract with and without 2% FBS) and cell culture media (RPMI + 2% FBS). In the former media, a shorter lag phase was observed for isolate serotypes 1 and 7F in presence of serum while in the later; growth yield was lower for all isolates with stationary phase approaching OD600 of 0.01 as compared to 1.0 in bacteriological media. In the replicative analysis at different growth phases of the isolates in cell culture media, growth capacity at 3 h post-incubation was frequently twice as that at 1 h, and that at early-log phase was frequently higher than that at mid-log phase at both post-incubation times. Adherence was frequently the least at early-log phase although the isolates were in the most active state of replication to increase the number of pneumococcal cells to adhere. At mid- and late-log phases, pneumococcal adherence was frequently higher although the replication was reduced. This study marks the potential correlation between pneumococcal growth fitness and adherence capacity whereby the later may not be superior during the early growth phase.
4.The emergence of Acinetobacter baumannii ST-6 multidrug resistant: A resilient biofilm producer, Malaysia
Jayakayatri Jeevajothi Nathan ; Mohd Nasir Mohd Desa ; Voon Chen Yong ; Parasakthi Navaratnam ; Navindra Kumari Palanisamy ; Eng Hwa Wong
Malaysian Journal of Microbiology 2016;12(4):265-269
Aims: The aim of this research is to explore the presence of multidrug-resistance (MDR) Acinetobacter baumannii
strains isolated from hospitalized patients in a tertiary-care center, Subang Jaya, Selangor, Malaysia and to compare
their genotypic and phenotypic characteristics.
Methodology and results: Clonal relationships were determined by multilocus sequence typing (MLST) and biofilm
forming ability was evaluated by using 2, 3 - bis (2 - methoxy - 4 - nitro - 5-sulfophenyl) - 5 - [(phenylamino) carbonyl] -
2H-tetrazolium hydroxide (XTT) reduction assay in microplates and Congo red agar method (CRA). Four virulence
genes coding for A. baumannii pilus usher-chaperone assembly protein, csuE gene; outer membrane protein, ompA
gene; biofilm poly-β-1, 6-Nacetylglucosamine (PNAG) synthesis protein, pgaA gene; and acinetobactin-mediated iron
acquisition protein, bauA gene were searched for in a collection of strains. Antimicrobial resistance against 11 antibiotics
were studied by broth microdilution method. Seventeen A. baumannii clinical strains were isolated and MLST showed
that the strains belonged to 5 distinct sequence types (STs), namely, ST-6, ST-265, ST-324, ST-325 and ST-432. Fiftythree
percent of the strains were resistant to 4 or more antibiotics. Twelve strains produced biofilm and out of them, 4
were strong biofilm producer, besides, these strong biofilm producers were MDR strains and belongs to ST-6. In
addition, all strains were ompA positive, biofilm producing strains were csuE and pgaA positive and only strong biofilm
producing strains were bauA positive.
Conclusion, significance and impact study: Our study demonstrates that the ST-6 strains in Malaysia could represent
MDR, capable of forming strong biofilm and possess csuE, ompA, pgaA and bauA genes, virulence characteristics that
probably help the bacteria to persist and cause infection.
Acinetobacter baumannii
5.Staphylococcus aureus Nasal Carriers Among Medical Students in A Medical School
Syafinaz Amin Nordin ; Nur Ain Nabila Za'im ; Nurul Nadzirah Sahari ; Siti Fatimah Jamaluddin ; Shahram Ahmadi ; Mohd Nasir Mohd Desa
The Medical Journal of Malaysia 2012;67(6):636-638
Staphylococcus aureus is usually considered a colonizer
but can result in infections under favourable conditions,
especially in the healthcare setting. Healthcare workers can be colonized by S. aureus, and may transmit them to
patients under their care. We conducted a cross sectional
study to determine the prevalence of S. aureus nasal
carriers among medical students in Universiti Putra
Malaysia (UPM) (from January to June 2011). Our study
involved 209 medical students comprising of 111 and 97 preclinical and clinical students respectively. A selfadministered questionnaire was distributed and nasal
swabs were collected. Upon identification, the antibiotic
susceptibility of the isolates was examined followed by
categorical analysis (Chi-square and Fisher’s exact tests)
with factors associated with S. aureus nasal carriage.
Twenty one (10%) S. aureus strains were isolated from 209
nasal swab samples. 14 isolates were from pre-clinical
students while the remaining seven were from clinical
students. There was no significant association between
gender, ethnicity, health status, skin infection and students’ exposure to hospital environment with S. aureus nasal carriage (p>0.05). Nineteen (90.5%) isolates were resistant to penicillin and there was also no significant association between penicillin resistant and the students’ groups. One (5.3%) isolate was resistant to erythromycin. There was no methicillin-resistant S. aureus isolated in this study.
6.Multilocus Sequence Typing Analysis of Invasive and Non-Invasive Group B Streptococcus of Hospital Origin in Malaysia
Menagah Ezhumalai ; AbdulRahman Muthanna ; Zarizal Suhail ; Nurul Diana Dzaraly ; Syafinaz Amin-Nordin ; Mohammad Noor Azmai Amal ; Mohd Nasir Mohd Desa
Malaysian Journal of Medical Sciences 2020;27(1):134-138
The aim of this study was to study the genotype of a hospital collection of Group B
Streptococcus (GBS) from invasive and non-invasive sites. Fifty-one pre-characterised human
of GBS were re-identified and further analysed by multilocus sequence typing (MLST) in relation
to previously published serotypes. Fifteen sequence types (ST) were found with ST1 being the
most predominant. ST1 was also associated with majority of the invasive isolates. The genotypic
distribution patterns of GBS in this study were largely in agreement with previous reports from
other countries indicating the tendency of certain genotypes to prevail in human infection settings.
7.Prevalence of macrolide resistance and in vitro activities of six antimicrobial agents against clinical isolates of Streptococcus pneumoniae from a multi-center surveillance in Malaysia
Jayakayatri Jeevajothi Nathan ; Niazlin Mohd Taib ; Mohd Nasir Mohd Desa ; Siti Norbaya Masri ; Rohani Md Yasin ; Farida Jamal ; Sreenivasa Rao Sagineedu ; Arunkumar Karunanidhi
The Medical Journal of Malaysia 2013;68(2):119-124
The in vitro activities of 6 antimicrobial agents against
clinical isolates of Streptococcus pneumoniae
(pneumococci) were investigated and the erythromycin
minimum inhibitory concentrations (MICs) were correlated
with the two major macrolide resistance determinants,
mef(A) and erm(B). MICs of commonly used antibiotics as
well as the presence of macrolide resistance determinant
genes in all isolates were tested. Seventy one
pneumococcal isolates collected at Institute for Medical
Research (IMR) were included in this study. Phenotypic
characterization, MIC determination using E-test strips and
polymerase chain reactions for antibiotic resistance
determination were included. Among the isolates, 25 (35.2%)
isolates were erythromycin susceptible, 3 (4.2%) were
intermediate and 42 (60.6%) were resistant. Fifty three
isolates (74.7%) were found with mef(A) alone, 15 (21.1%)
isolates with erm(B) + mef(A) combination and 3 (4.2%)
isolates with none of the two genes. The in vitro activity of penicillin, amoxicillin clavulanic acid, ceftriaxone and
cefotaxime is superior to trimethoprim-sulfamethoxazole
and erythromycin. In conclusion, pneumococcal isolates in
this study were highly susceptible to penicillin with very low MICs. However, a very high prevalence rate of erythromycin resistance was observed. Erythromycin resistant S.pneumoniae isolates with both mef(A) and erm(B) showed very high MICs ≥256 μg/mL.
8.Genotypic and phenotypic characterization of methicillin resistance determinants and β-lactamase in Staphylococcus species
Abdul Rahim Abdul Rachman ; Norhidayah Mat Azis ; Pung Hui Ping ; Zarizal Suhaili ; Syafinaz Amin Nordin ; Zulkefley Othman ; Mohd Nasir Mohd Desa
Malaysian Journal of Microbiology 2017;13(4):308-317
Aims: To characterize the genotypic distribution of mec complex, bla complex, methicillin-resistance level (cefoxitinMIC)
and β-lactamase activity in carriage methicillin-resistant Staphylococcus species for a potential correlation.
Methodology and results: Biochemical test, 30 µg cefoxitin diffusion disc test, cefoxitin E-test, mec and bla complexes
distributions, Pbp2a and β-lactamase assays were conducted to characterize phenotypic and genotypic of MRSA and
MRCoNS in our collection. Phylogenetic tree was constructed using MEGA6 software to trace the diversity of blaZ gene
of MRSA and MRCoNS. Sixteen MRSA and nineteen MRCoNS were identified by biochemical tests followed by 30 µg
cefoxitin antibiotic disc susceptibility test and mecA gene screening. Twenty nine isolates carry complete mecA genes
(2.1 kb), incomplete mec regulator (negative or truncated) and positive Pbp2a assay for both MRSA and MRCoNS. Only
MRCoNS SC177 isolate with cefoxitin MIC of 32 µg/mL carries complete mec complex. Thirty-one of thirty-five isolates
carry complete bla complex (blaZ, blaRI, blaI) with 10 MRSA produce strong β-lactamase and cefoxitin MIC of ≥12
µg/mL. Only 4 MRCoNS with cefoxitin MIC of ≤8 µg/mL produce strong β-lactamase. The diversity of blaZ gene was
demonstrated by phylogenetic analysis and unusual amino acid mutation at position 145 for MRSA SA60 isolate may
compromise its β-lactamase activity with low cefoxitin MIC level (2 µg/mL).
Conclusions, significance and impact of the study: Isolates that carry complete complete mecA gene were largely
consistent with the expression of Pbp2a. Nevertheless, there is no clear correlation of mec regulator genes in relation to
cefoxitin-MIC in both methicillin resistant (MR) Isolates that carry Staphylococcus species. On the other hand, various
expression level of β-lactamase may correlate with cefoxitin-MIC level in MRSA as compared to MRCoNS.
9.Characterization and antimicrobial activities of two Streptomyces isolates from soil in the periphery of Universiti Putra Malaysia
Nurul Zarith Mohamad Zin ; Nor Asmara Tasrip ; Mohd Nasir Mohd Desa,* ; Cheah Yoke Kqueen ; Zainul Amiruddin Zakaria ; Rukman Awang Hamat ; Mariana Nor Shamsudin,
Tropical Biomedicine 2011;28(3):651-660
This study was to assess the identification and antimicrobial activities of two
actinomycete isolates. The two isolates designated as B8 and C2, were isolated from a patch
of soil in the peripheral area of Universiti Putra Malaysia by streaking on starch casein agar
after standard serial dilution procedures. Their antimicrobial activities were first evaluated
against eight clinical laboratory strains namely Bacillus sp., Enterococcus sp., Escherichia
coli, Klebsiella sp., Pseudomonas sp., Salmonella sp., Staphylococcus aureus, and
Staphylococcus epidermidis by perpendicular streak method on Mueller Hinton and Tryptic
Soy agar. In both media, a broad-spectrum antibacterial activity was observed for both
isolates, with B8 against all the test bacteria and C2 against five of them (Bacillus sp., E. coli,
Pseudomonas sp., S. aureus and S. epidermidis). Re-assessment against E. coli ATCC 25922
and S. aureus ATCC 25923 strains by similar method showed antibacterial activities by
isolate B8 against both ATTC strains while C2 only against S. aureus ATCC 25923. Streptomyces
griseus ATCC 10137 was included in the later experiment and showed antibacterial activity
against both ATCC strains. Subsequently, the two isolates were identified by PCR/sequencing
techniques and phylogenetic analysis to be Streptomyces species (>93% homology based on
16S rRNA and rpoB genes). Characterization on cultural characteristic and viable count at
different temperatures (37ºC and 28ºC), on different microbiological media (AIA, ISP-2, MHA,
NA, PDA and TSA), were performed. More morphological features were observed on ISP-2 for
both isolates. A higher growth yield was also observed at 28ºC in all media but in comparing
that between the two isolates, isolate B8 outnumbered C2 at all experimental conditions. The
observed variation in cultural traits and growth yield indicate unique properties between the
two antibiotic-producing isolates
10.The PUTRA Press-fit System as An Alternative Femoral Fixation Technique for Posterior Cruciate Ligament Reconstruction – A Technical Note and Outcome Evaluation
Nasir Mohd Nizlan1, Paisal Hussin1, Raymond Yeak Dieu Kiat1, Mohd Zaidi Saleh2, Shahrulazua Ahmad3
Malaysian Journal of Medicine and Health Sciences 2019;15(3):148-152
Abstract
We describe our technique of single-bundle PCL reconstruction using a bony femoral press-fit system. 9 patients underwent PCL reconstruction using our pressfit system. The surgical procedure is described in detail. Post-operatively, 5 patients were available for assessment and review. Four patients gave a final Lysholm score of 92 – 100%. Three patients gave a Hospital for Special Surgery (HSS) score of excellent, one fair and one poor. Two patients gave a reduced Tegner activity score post-operatively while the other three gave a similar score post-operatively. Assessment using KT-1000 revealed four patients with a side-to-side difference of less than 3 mm (average side-to-side difference, 1.87 mm), while one patient exhibited a side-to-side difference of 5.8 mm. We believe that our technique enhances tunnel healing through usage of a bone-plug fixation and provides a cheap alternative for graft fixation on the femoral side in PCL reconstruction.