Displaying publications 1 - 20 of 127 in total

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  1. Fulltext Screening for New Delhi metallo-β-lactamase-1 in Enterobacteriaceae: Is there a role for the modified Hodge test?
    Abidin NZ, Sulong A, Alfizah H, Ding CH, Muttaqillah NA, Rahman MM
    Pak J Med Sci, 2015 Nov-Dec;31(6):1340-3.
    PMID: 26870093 DOI: 10.12669/pjms.316.8159
    The New Delhi metallo-β-lactamase-1 (NDM-1) enzyme is a plasmid-encoded enzyme that inactivates carbapenem antibiotics. This study aims to ascertain if the modified Hodge test (MHT) has a role in screening for NDM-1 in Enterobacteriaceae with reduced carbapenem susceptibility.
    Matched MeSH terms: beta-Lactamases
  2. Fulltext T4-like coliphage ΦKAZ14 virulent to pathogenic and extended spectrum β-lactamase-producing Escherichia coli of poultry origin
    Ahmad KA, Mohanmmed AS, Abas F, Chin SC
    Virol Sin, 2015 Feb;30(1):73-5.
    PMID: 25662886 DOI: 10.1007/s12250-014-3541-8
    Matched MeSH terms: beta-Lactamases/genetics; beta-Lactamases/metabolism*
  3. Isolation of Moraxella catarrhalis from sputum specimens of Malaysian patients
    Ahmad N, Cheong YM, Tahir HM
    Malays J Pathol, 1994 Jun;16(1):63-7.
    PMID: 16329578
    Moraxella catarrhalis has gained reputation as a pathogen in the lower respiratory tract especially in patients with underlying chronic lung diseases. It is considered significant when isolated from sputum specimens of adults with respiratory tract infections. A study was carried out to determine the prevalence of Moraxella catarrhalis isolated in sputum specimens and beta-lactamase production of these isolates. Sputum specimens sent to the Bacteriology division, Institute for Medical Research from April 1990 until April 1993 were screened for Moraxella catarrhalis. A total of 1678 sputum specimens were processed and Moraxella catarrhalis was isolated from 15 (0.89%) of the sputum specimens. Six out of 15 (40%) were isolated from patients with chronic lung disease. Eight out of 15 (47%) were beta-lactamase producers. Moraxella catarrhalis isolated in good-quality sputum must not be disregarded and should be looked for especially in patients with chronic obstructive pulmonary disease. Beta-lactamase production should be tested on all isolates so that appropriate treatment can be given. All the isolates in this study were sensitive to cotrimoxazole.
    Matched MeSH terms: beta-Lactamases/metabolism
  4. Characterization of the first isolate of Klebsiella pneumoniae carrying New Delhi metallo-β-lactamase and other extended spectrum β-lactamase genes from Malaysia
    Ahmad N, Hashim R, Shukor S, Mohd Khalid KN, Shamsudin F, Hussin H
    J Med Microbiol, 2013 May;62(Pt 5):804-806.
    PMID: 23449878 DOI: 10.1099/jmm.0.050781-0
    Matched MeSH terms: beta-Lactamases/genetics; beta-Lactamases/metabolism*
  5. Fulltext Phylogenetically Diverse Escherichia coli Strains from Chicken Coharbor Multiple Carbapenemase-Encoding Genes (bla NDM -bla OXA-blaIMP)
    Aklilu E, Harun A, Singh KKB, Ibrahim S, Kamaruzzaman NF
    Biomed Res Int, 2021;2021:5596502.
    PMID: 34660793 DOI: 10.1155/2021/5596502
    Carbapenem-resistant Enterobacteriaceae (CRE) has been a public health risk in several countries, and recent reports indicate the emergence of CRE in food animals. This study was conducted to investigate the occurrence, resistance patterns, and phylogenetic diversity of carbapenem-resistant E. coli (CREC) from chicken. Routine bacteriology, PCR detection of E. coli species, multiplex PCR to detect carbapenemase-encoding genes, and phylogeny of CRE E. coli were conducted. The results show that 24.36% (19/78) were identified as CREC based on the phenotypic identifications of which 17 were positive for the tested carbapenemases genes. The majority, 57.99% (11/19), of the isolates harbored multiple carbapenemase genes. Four isolates harbored all bla NDM, bla OXA, and bla IMP, and five and two different isolates harbored bla NDM and bla OXA and bla OXA and bla IMP, respectively. The meropenem, imipenem, and ertapenem MIC values for the isolates ranged from 2 μg/mL to ≥256 μg/mL. Phylogenetic grouping showed that the CREC isolates belonged to five different groups: groups A, B1, C, D, and unknown. The detection of CREC in this study shows that it has become an emerging problem in farm animals, particularly, in poultry farms. This also implies the potential public health risks posed by CRE from chicken to the consumers.
    Matched MeSH terms: beta-Lactamases/genetics*
  6. MCR-1 Gene Encoded Colistin-Resistant Escherichia coli in Raw Chicken Meat and Bean Sprouts in Malaysia
    Aklilu E, Raman K
    Int J Microbiol, 2020;2020:8853582.
    PMID: 32774381 DOI: 10.1155/2020/8853582
    This study was conducted to detect the presence of colistin-resistant Escherichia coli (E. coli) in raw chicken meat and bean sprouts collected from local markets and to determine the antimicrobial resistance patterns of the E. coli isolates. A total of 100 samples, comprised of 50 raw chicken meat and 50 bean sprouts, were collected and processed. Kirby-Bauer method was used to determine the antimicrobial resistance patterns, and PCR amplification was used to detect E. coli species-specific and colistin resistance (mcr-1 and mcr-2) genes. The results showed that 52.1% (12/23) of the E. coli isolated from raw chicken meat were positive for the colistin resistance encoding gene, mcr-1, whereas all the E. coli isolates from bean sprouts were negative for colistin resistance encoding genes. The findings show that chicken meat contaminated with colistin-resistant E. coli may pose public health risk to the consumers. Hence, prudent usage of antibiotics and hygienic handling of food items helps to prevent and combat the risks of spreading of colistin-resistant E. coli and the public health risks it may pose. More comprehensive and large-scale studies focusing on all the possible sources of colistin-resistant E. coli are recommended.
    Matched MeSH terms: beta-Lactamases
  7. Optimizing of pharmaceutical active compounds biodegradability in secondary effluents by β-lactamase from Bacillus subtilis using central composite design
    Al-Gheethi A, Noman E, Radin Mohamed RMS, Ismail N, Bin Abdullah AH, Mohd Kassim AH
    J Hazard Mater, 2019 03 05;365:883-894.
    PMID: 30497042 DOI: 10.1016/j.jhazmat.2018.11.068
    Biodegradation of pharmaceuticals active compounds (PACs) in secondary effluents by using B. subtilis 2012WTNC as a function of β-lactamase was optimized using response surface methodology (RSM) designed by central composite design (CCD). Four factors including initial concentration of bacteria (1-6 log10 CFU mL-1), incubation period (1-14 days), incubation temperature (20-40 °C) and initial concentration of PACs (1-5 mg L-1) were investigated. The optimal operating factors for biodegradation process determined using response surface methodology (RSM) was recorded with 5.57 log10 CFU mL-1 of B. subtilis, for 10.38 days, at 36.62 °C and with 4.14 mg L-1 of (cephalexin/amoxicillin) with R2 coefficient of 0.99. The biodegradation was 83.81 and 93.94% respectively. The relationship among the independent variables was significant (p 
    Matched MeSH terms: beta-Lactamases/metabolism*
  8. Fulltext Molecular analysis of ciprofloxacin resistance mechanisms in Malaysian ESBL-producing Klebsiella pneumoniae isolates and development of mismatch amplification mutation assays (MAMA) for rapid detection of gyrA and parC mutations
    Al-Marzooq F, Mohd Yusof MY, Tay ST
    Biomed Res Int, 2014;2014:601630.
    PMID: 24860827 DOI: 10.1155/2014/601630
    Ninety-three Malaysian extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolates were investigated for ciprofloxacin resistance. Two mismatch amplification mutation (MAMA) assays were developed and used to facilitate rapid detection of gyrA and parC mutations. The isolates were also screened for plasmid-mediated quinolone resistance (PMQR) genes including aac(6')-Ib-cr, qepA, and qnr. Ciprofloxacin resistance (MICs 4- ≥ 32  μ g/mL) was noted in 34 (37%) isolates, of which 33 isolates had multiple mutations either in gyrA alone (n = 1) or in both gyrA and parC regions (n = 32). aac(6')-Ib-cr was the most common PMQR gene detected in this study (n = 61), followed by qnrB and qnrS (n = 55 and 1, resp.). Low-level ciprofloxacin resistance (MICs 1-2  μ g/mL) was noted in 40 (43%) isolates carrying qnrB accompanied by either aac(6')-Ib-cr (n = 34) or a single gyrA 83 mutation (n = 6). Ciprofloxacin resistance was significantly associated with the presence of multiple mutations in gyrA and parC regions. While the isolates harbouring gyrA and/or parC alteration were distributed into 11 PFGE clusters, no specific clusters were associated with isolates carrying PMQR genes. The high prevalence of ciprofloxacin resistance amongst the Malaysian ESBL-producing K. pneumoniae isolates suggests the need for more effective infection control measures to limit the spread of these resistant organisms in the hospital.
    Matched MeSH terms: beta-Lactamases/metabolism*
  9. Fulltext Molecular Analysis of Antibiotic Resistance Determinants and Plasmids in Malaysian Isolates of Multidrug Resistant Klebsiella pneumoniae
    Al-Marzooq F, Mohd Yusof MY, Tay ST
    PLoS One, 2015;10(7):e0133654.
    PMID: 26203651 DOI: 10.1371/journal.pone.0133654
    Infections caused by multidrug resistant Klebsiella pneumoniae have been increasingly reported in many parts of the world. A total of 93 Malaysian multidrug resistant K. pneumoniae isolated from patients attending to University of Malaya Medical Center, Kuala Lumpur, Malaysia from 2010-2012 were investigated for antibiotic resistance determinants including extended-spectrum beta-lactamases (ESBLs), aminoglycoside and trimethoprim/sulfamethoxazole resistance genes and plasmid replicons. CTX-M-15 (91.3%) was the predominant ESBL gene detected in this study. aacC2 gene (67.7%) was the most common gene detected in aminoglycoside-resistant isolates. Trimethoprim/sulfamethoxazole resistance (90.3%) was attributed to the presence of sul1 (53.8%) and dfrA (59.1%) genes in the isolates. Multiple plasmid replicons (1-4) were detected in 95.7% of the isolates. FIIK was the dominant replicon detected together with 13 other types of plasmid replicons. Conjugative plasmids (1-3 plasmids of ~3-100 kb) were obtained from 27 of 43 K. pneumoniae isolates. An ESBL gene (either CTX-M-15, CTX-M-3 or SHV-12) was detected from each transconjugant. Co-detection with at least one of other antibiotic resistance determinants [sul1, dfrA, aacC2, aac(6')-Ib, aac(6')-Ib-cr and qnrB] was noted in most conjugative plasmids. The transconjugants were resistant to multiple antibiotics including β-lactams, gentamicin and cotrimoxazole, but not ciprofloxacin. This is the first study describing the characterization of plasmids circulating in Malaysian multidrug resistant K. pneumoniae isolates. The results of this study suggest the diffusion of highly diverse plasmids with multiple antibiotic resistance determinants among the Malaysian isolates. Effective infection control measures and antibiotic stewardship programs should be adopted to limit the spread of the multidrug resistant bacteria in healthcare settings.
    Matched MeSH terms: beta-Lactamases/genetics
  10. Identification of a novel SHV-β-lactamase variant (SHV-144) in a Malaysian multidrug-resistant Klebsiella pneumoniae isolate
    Al-Marzooq F, Yusof MY, Tay ST
    Jpn J Infect Dis, 2013;66(6):555-7.
    PMID: 24270152
    Matched MeSH terms: beta-Lactamases/genetics*
  11. Emergence of Klebsiella pneumoniae producing dual carbapenemases (NDM-1 and OXA-232) and 16S rRNA methylase (armA) isolated from a Malaysian patient returning from India
    Al-Marzooq F, Ngeow YF, Tay ST
    Int J Antimicrob Agents, 2015 Apr;45(4):445-6.
    PMID: 25631676 DOI: 10.1016/j.ijantimicag.2014.12.013
    Matched MeSH terms: beta-Lactamases/genetics*
  12. Fulltext Complete Genome Sequencing of Acinetobacter baumannii AC1633 and Acinetobacter nosocomialis AC1530 Unveils a Large Multidrug-Resistant Plasmid Encoding the NDM-1 and OXA-58 Carbapenemases
    Alattraqchi AG, Mohd Rani F, A Rahman NI, Ismail S, Cleary DW, Clarke SC, et al.
    mSphere, 2021 Jan 27;6(1).
    PMID: 33504662 DOI: 10.1128/mSphere.01076-20
    Carbapenem-resistant Acinetobacter spp. are considered priority drug-resistant human-pathogenic bacteria. The genomes of two carbapenem-resistant Acinetobacter spp. clinical isolates obtained from the same tertiary hospital in Terengganu, Malaysia, namely, A. baumannii AC1633 and A. nosocomialis AC1530, were sequenced. Both isolates were found to harbor the carbapenemase genes blaNDM-1 and blaOXA-58 in a large (ca. 170 kb) plasmid designated pAC1633-1 and pAC1530, respectively, that also encodes genes that confer resistance to aminoglycosides, sulfonamides, and macrolides. The two plasmids were almost identical except for the insertion of ISAba11 and an IS4 family element in pAC1633-1, and ISAba11 along with relBE toxin-antitoxin genes flanked by inversely orientated pdif (XerC/XerD) recombination sites in pAC1530. The blaNDM-1 gene was encoded in a Tn125 composite transposon structure flanked by ISAba125, whereas blaOXA-58 was flanked by ISAba11 and ISAba3 downstream and a partial ISAba3 element upstream within a pdif module. The presence of conjugative genes in plasmids pAC1633-1/pAC1530 and their discovery in two distinct species of Acinetobacter from the same hospital are suggestive of conjugative transfer, but mating experiments failed to demonstrate transmissibility under standard laboratory conditions. Comparative sequence analysis strongly inferred that pAC1633-1/pAC1530 was derived from two separate plasmids in an IS1006-mediated recombination or transposition event. A. baumannii AC1633 also harbored three other plasmids designated pAC1633-2, pAC1633-3, and pAC1633-4. Both pAC1633-3 and pAC1633-4 are cryptic plasmids, whereas pAC1633-2 is a 12,651-bp plasmid of the GR8/GR23 Rep3-superfamily group that encodes the tetA(39) tetracycline resistance determinant in a pdif module.IMPORTANCE Bacteria of the genus Acinetobacter are important hospital-acquired pathogens, with carbapenem-resistant A. baumannii listed by the World Health Organization as the one of the top priority pathogens. Whole-genome sequencing of carbapenem-resistant A. baumannii AC1633 and A. nosocomialis AC1530, which were isolated from the main tertiary hospital in Terengganu, Malaysia, led to the discovery of a large, ca. 170-kb plasmid that harbored genes encoding the New Delhi metallo-β-lactamase-1 (NDM-1) and OXA-58 carbapenemases alongside genes that conferred resistance to aminoglycosides, macrolides, and sulfonamides. The plasmid was a patchwork of multiple mobile genetic elements and comparative sequence analysis indicated that it may have been derived from two separate plasmids through an IS1006-mediated recombination or transposition event. The presence of such a potentially transmissible plasmid encoding resistance to multiple antimicrobials warrants vigilance, as its spread to susceptible strains would lead to increasing incidences of antimicrobial resistance.
    Matched MeSH terms: beta-Lactamases/genetics*
  13. Interaction of LysM BON family protein domain with carbapenems: A putative mechanism of carbapenem resistance
    Ali A, Kumar R, Khan A, Khan AU
    Int J Biol Macromol, 2020 Oct 01;160:212-223.
    PMID: 32464197 DOI: 10.1016/j.ijbiomac.2020.05.172
    Carbapenem resistance in Gram-negative pathogens has become a global concern for health workers worldwide. In one of our earlier studies, a Klebsiella pneumoniae-carbapenemase-2 producing strain was induced with meropenem to explore differentially expressed proteins under induced and uninduced conditions. There is, LysM domain BON family protein, was found over 12-fold expressed under the induced state. A hypothesis was proposed that LysM domain protein might have an affinity towards carbapenem antibiotics making them unavailable to bind with their target. Hence, we initiated a study to understand the binding mode of carbapenem with LysM domain protein. MICs of imipenem and meropenem against LysM clone were increased by several folds as compared to NP-6 clinical strain as well as DH5 α (PET-28a KPC-2) clone. This study further revealed a strong binding of both antibiotics to LysM domain protein. Molecular simulation studies of LysM domain protein with meropenem and imipenem for 80 ns has also showed stable structure. We concluded that overexpressed LysM domain under induced condition interacted with carbapenems, leading to enhanced resistance as proved by high MIC values. Hence, the study proved the proposed hypothesis that the LysM domain plays a significant role in the putative mechanism of antibiotics resistance.
    Matched MeSH terms: beta-Lactamases/metabolism
  14. Fulltext Risk factors and spatial distribution of extended spectrum β-lactamase-producing- Escherichia coli at retail poultry meat markets in Malaysia: a cross-sectional study
    Aliyu AB, Saleha AA, Jalila A, Zunita Z
    BMC Public Health, 2016 08 02;16:699.
    PMID: 27484086 DOI: 10.1186/s12889-016-3377-2
    BACKGROUND: The significant role of retail poultry meat as an important exposure pathway for the acquisition and transmission of extended spectrum β-lactamase-producing Escherichia coli (ESBL-EC) into the human population warrants understanding concerning those operational practices associated with dissemination of ESBL-EC in poultry meat retailing. Hence, the objective of this study was to determine the prevalence, spatial distribution and potential risk factors associated with the dissemination of ESBL-EC in poultry meat retail at wet-markets in Selangor, Malaysia.

    METHODS: Poultry meat (breast, wing, thigh, and keel) as well as the contact surfaces of weighing scales and cutting boards were sampled to detect ESBL-EC by using culture and disk combination methods and polymerase chain reaction assays. Besides, questionnaire was used to obtain data and information pertaining to those operational practices that may possibly explain the occurrence of ESBL-EC. The data were analysed using logistic regression analysis at 95 % CI.

    RESULTS: The overall prevalence of ESBL-EC was 48.8 % (95 % CI, 42 - 55 %). Among the risk factors that were explored, type of countertop, sanitation of the stall environment, source of cleaning water, and type of cutting board were found to be significantly associated with the presence of ESBL-EC.

    CONCLUSIONS: Thus, in order to prevent or reduce the presence of ESBL-EC and other contaminants at the retail-outlet, there is a need to design a process control system based on the current prevailing practices in order to reduce cross contamination, as well as to improve food safety and consumer health.

    Matched MeSH terms: beta-Lactamases/metabolism*
  15. Emergence of ST119 Acinetobacter pittii co-harbouring NDM-1 and OXA-58 in Malaysia
    Ang GY, Yu CY, Cheong YM, Yin WF, Chan KG
    Int J Antimicrob Agents, 2016 Feb;47(2):168-9.
    PMID: 26742728 DOI: 10.1016/j.ijantimicag.2015.11.008
    Matched MeSH terms: beta-Lactamases/secretion*
  16. Fulltext Enterobacter gergoviae peritonitis in a patient on chronic ambulatory peritoneal dialysis - first reported case
    Anna Misya’il Abdul Rashid, Lim, Christopher Thiam Seong
    Malaysian Journal of Medicine and Health Sciences, 2017;13(2):67-69.
    MyJurnal
    Enterobacter gergoviae is a gram negative rod-shaped opportunistic organism reported to cause urinary and respiratory tract infections, but peritonitis caused by this organism is unknown. We report a case of 50-year-old patient on peritoneal dialysis (PD) presented with Enterobacter gergoviae peritonitis with septic shock. Despite Intraperitoneal (IP) cloxacillin 250mg qid and IP ceftazidime 1gram q24h and subsequent escalation with IP amikacin 2mg/kg q24h and IP vancomycin 15mg/kg q24h within the next 48 hours, his peritonitis remained refractory and required catheter removal. Although Enterobacter gergoviae is naturally sensitive to aminoglycosides, carbapenems and quinolones, it reacts differently to the beta lactam antibiotics. Their resistance to third-generation cephalosporins is fast emerging and treatment with third-generation cephalosporins may cause AmpC-overproducing mutants. The majority of
    Enterobacteriaceae, including Extended-spectrum beta-lactamases producers, remain susceptible to carbapenems. Our report provides an unfavourable course of E. gergoviae peritonitis likely due to acquired secondary drug resistance during the therapy period.
    Matched MeSH terms: beta-Lactamases
  17. Antibiotic resistance patterns in nosocomial gram-negative bacterial infections in units with heavy antibiotic usage
    Ariffin H, Navaratnam P, Kee TK, Balan G
    J Trop Pediatr, 2004 Feb;50(1):26-31.
    PMID: 14984166
    The pattern of antibiotic resistance amongst gram-negative bacteria (GNB) in paediatric units, which have heavy empirical usage of broad-spectrum antibiotics, was studied prospectively over a 6-month period. A total of 200 consecutive, non-duplicate gram-negative isolates were obtained from 109 patients admitted to intensive care and oncology units in two hospitals. The commonest isolates were Klebsiella spp (36.5 per cent) and Pseudomonas (20.0 per cent). The isolates showed lower susceptibility rates to the third-generation cephalosporins (47-62 per cent) compared with cefepime (91 per cent), imipenem (90 per cent) and ciprofloxacin (99 per cent). Fifty-four (52.8 per cent) Klebsiella and Escherichia coli isolates were determined to be extended-spectrum beta-lactamase (ESBL) producing strains. Antibiotics found to be effective against ESBL-producers were imipenem and ciprofloxacin. The high resistance rate amongst GNB to third-generation cephalosporins is a likely consequence of heavy empirical usage of this group of antibiotics. The carbapenems and quinolones remain useful agents in the management of patients admitted to these units.
    Matched MeSH terms: beta-Lactamases/biosynthesis
  18. Population density and antibiotic resistant of bacteria from bivalve (Perna viridis and Anadara granosa)
    Asmat Armad, Nur Diana Mehat, Usup G, Rahimi Hamid
    Sains Malaysiana, 2014;43:543-550.
    This study was carried out to know the bacteria population density in the blood cockle (Anadara granosa) and green lipped mussel (Perna viridis), to analyse the bacteria resistance towards antibiotics and antimicrobial activity of isolates against selected pathogen. Samples of blood cockle and green lipped mussel were obtained from five areas in Kedah and Negeri Sembilan. Bacterial population densities in mussels and cockles were 3 x 102 - 8 x 108 cFulmL and 5 x 102 - 5 x 108 cFulmL, respectively. A total of 162 isolates were obtained, of which 131 isolates were from mussels and 31 isolates were from cockles. Vibrio sp. was the most dominant genus in both types of samples. Antibiotic testing of all isolates showed most were resistant to Penicillin (10 U) and most were sensitive to Ciprofloxacin (5 Jig). Most isolates (160/162) showed resistance to at least two antibiotics and 10 isolates were resistant to more than five antibiotics. Multiple antibiotic resistance indices (MAR) were calculated based on the antibiotic resistance results. Most isolates had a MAR index value of 02 which indicated the isolates were not contaminated with antibiotic residues. The highest index value was 0 .7 . Fifteen out of 39 isolates which produced beta-lactamase enzyme were tested for antimicrobial activity against selected pathogen. Results indicated that antimicrobial activity were varies among the isolates. Isolate smii-Ip produced antimicrobial activity against six out of the nine tested pathogen and none of the isolates active against Pseudomonas mirabilis.
    Matched MeSH terms: beta-Lactamases
  19. IMP-4-producing Pseudomonas aeruginosa in a French patient repatriated from Malaysia: impact of early detection and control measures
    Bert F, Vanjak D, Leflon-Guibout V, Mrejen S, Delpierre S, Redondo A, et al.
    Clin Infect Dis, 2007 Mar 1;44(5):764-5.
    PMID: 17278079
    Matched MeSH terms: beta-Lactamases/genetics; beta-Lactamases/metabolism*
  20. Molecular characterization of carbapenemase and cephalosporinase genes among clinical isolates of Acinetobacter baumannii in a tertiary medical centre in Malaysia
    Biglari S, Alfizah H, Ramliza R, Rahman MM
    J Med Microbiol, 2015 Jan;64(Pt 1):53-8.
    PMID: 25381148 DOI: 10.1099/jmm.0.082263-0
    Antimicrobial resistance in Acinetobacter baumannii is a growing public health concern and an important pathogen in nosocomial infections. We investigated the genes involved in resistance to carbapenems and cephalosporins in clinical A. baumannii isolates from a tertiary medical centre in Malaysia. A. baumannii was isolated from 167 clinical specimens and identified by sequencing of the 16S rRNA and rpoB genes. The MIC for imipenem, meropenem, ceftazidime and cefepime were determined by the E-test method. The presence of carbapenemase and cephalosporinase genes was investigated by PCR. The isolates were predominantly nonsusceptible to carbapenems and cephalosporins (>70 %) with high MIC values. ISAba1 was detected in all carbapenem-nonsusceptible A. baumannii harbouring the blaOXA-23-like gene. The presence of blaOXA-51-like and ISAba1 upstream of blaOXA-51 was not associated with nonsusceptibility to carbapenems. A. baumannii isolates harbouring ISAba1-blaADC (85.8 %) were significantly associated with nonsusceptibility to cephalosporins (P<0.0001). However, ISAba1-blaADC was not detected in a minority (<10 %) of the isolates which were nonsusceptible to cephalosporins. The acquired OXA-23 enzymes were responsible for nonsusceptibility to carbapenems in our clinical A. baumannii isolates and warrant continuous surveillance to prevent further dissemination of this antibiotic resistance gene. The presence of ISAba1 upstream of the blaADC was a determinant for cephalosporin resistance. However, the absence of this ISAba1-blaADC in some of the isolates may suggest other resistance mechanisms and need further investigation.
    Matched MeSH terms: beta-Lactamases/genetics*
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