Enterobacteriaceae encoding plasmid-mediated AmpC (pAmpC) β-lactamases confer resistance to the third generation cephalosporins. pAmpC association with extended spectrum β-lactamases (ESBLs), ...plasmid-mediated quinolone resistance (PMQR) and aminoglycoside modifying enzymes (AMEs) is well documented. There are limited data regarding the epidemiology and clinical significance of pAmpC in Saudi Arabia. This study aimed to determine the prevalence of pAmpC and its coexistence with ESBLs, PMQR and AMEs in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis isolates in Saudi hospitals from January to December 2015.
The VITEK 2 system was used for organism identification and susceptibility testing. PCR and sequencing were used to detect pAmpC, ESBL, AME and PMQR genes.
Out of 3625 isolates of E. coli, K. pneumoniae and P. mirabilis, 200 cefoxitin-resistant isolates were identified, making the prevalence of cefoxitin resistance 5.5 % (200/3625). CMY-2 and DHA were detected in 24 and 12 isolates, respectively. The prevalence of pAmpC was 1 % (36/3625). In several isolates, pAmpC β-lactamases were associated with PMQR genes including aac(6')-Ib-cr and qnrB and/or with AMEs including aacA4, aacC2, aadA1, aphA6, armA and rmtB genes. No ESBLs were detected in pAmpC β-lactamase-harbouring isolates.
To our knowledge, this is the first study determining the prevalence of pAmpC β-lactamases and their association with PMQR and/or AME genes in Saudi Arabia and the Gulf States. CMY-2 is the most prevalent pAmpC β-lactamase in this study. These data emphasize the importance of surveillance studies and implementation of antimicrobial stewardship programmes to reduce infections caused by such resistant organisms.
Carbapenem-resistant Acinetobacter baumannii is a major health problem worldwide, especially in intensive care units (ICUs). This study aimed to detect the prevalence of A. baumannii colonization of ...the gastrointestinal tract of patients admitted to the ICU in two hospitals in Saudi Arabia. In addition, it aimed to characterize the molecular mechanisms of carbapenem resistance in these isolates. From January to June 2014, 565 rectal swab specimens were screened for Acinetobacer strains and carbapenem resistance using CHROMagar Acinetobacter and CHROMagar KPC agar plates, respectively. Organism identification and susceptibility were detected using the Vitek 2 system. A total of 47 Acinetobacter spp. were detected, and 35 were resistant to carbapenem, making the prevalence of Acinetobacter spp. 8.3% (47/565) and carbapenem resistance (6.2%, 35/565). The 47 strains showed remarkable clonal diversity as revealed by PFGE. Using PCR, OXA-51, a chromosomal marker for A. baumannii, was detected in 46 strains. OXA-23 β-lactamase was detected in all 35 carbapenem-resistant A. baumannii. No IMP, VIM, SPM, SIM, GIM, KPC or NDM β-lactamases were detected in these isolates. Thus, OXA-23 was the main mechanism of carbapenem resistance in these isolates. To the best of our knowledge, this is the first study to detect the prevalence of Acinetobacter colonization in the digestive tract of ICU patients in Saudi Arabia. This study revealed the importance of having well-established protocols for early identification of these multidrug-resistant organisms, optimizing infection-control strategies and having active surveillance studies to reduce morbidity, mortality and cost.
The resistance determinants for carbapenems, fluoroquinolones and aminoglycosides were characterized in 16 extensively drug-resistant Klebsiella pneumoniae (XDRKPN) strains collected from Saudi ...hospitals during 2014.
PCR and sequencing were used to detect: blaKPC, blaNDM, blaVIM, blaIMP-1,blaOXA-48, blaCTX-M, blaTEM, blaSHV and ampC for β-lactam resistance; qnrA, qnrB, qnrS, aac(6')-Ib-cr, qepA and mutations of gyrA and parC for fluoroquinolone resistance; and aacA4, aacC2, aadA1, aphA6, armA and rmtB for aminoglycoside resistance. Enterobacterial repetitive intergenic consensus sequence-based PCR was performed to detect the clonal relatedness.
All isolates encoded blaCTX-M, aacC2 and aphA6, together with mutations in gyrA and parC. blaOXA-48, blaNDM-1, aadA1, aacA4, qnrB, aac(6')-Ib-cr, armA and/or rmtB were detected in different strains. At least 93.2 % clonal relatedness was detected among these strains.
To our knowledge, this is the first report describing XDRKPN encoding at least seven resistance determinants and harbouring methyltransferases in Saudi Arabia.
This study characterized the occurrence of carbapenem resistance of Acinetobacter baumannii isolates in a tertiary care hospital in Saudi Arabia. From January 2010 until February 2012, Acinetobacter ...spp. isolates were collected from different wards and were identified using Vitek 2 system and 16S rRNA gene sequencing. Vitek 2 system and Etest were used for susceptibility testing. PCR and Pulse field gel electrophoresis (PFGE) were used for detecting and typing genes associated with carbapenem resistance. A total of 141 isolates were identified as A. baumannii. A total of 46 (32.6%) isolates were carbapenem-resistant Acinetobacter baumannii (CRAB) isolates and had wild diversity by PFGE. Metallo ?-lactamase confirmatory test was positive for 43 isolates with negative PCR for blaIMP and blaVIM. Among the 46 CRAB strains, 37 isolates harbored blaOXA-23 which was encoded downstream of ISAba1 and 1 isolate had ISAba1 encoded upstream blaOXA-51. These data reveal that the interhospital transmission of CRAB isolates was apparently insignificant. BlaOXA-23 adjacent to ISAba1 was the main mechanism of carbapenem resistance in these isolates. To our knowledge, this is the first molecular study characterizing carbapenem resistance in A. baumannii in the Eastern Province of Saudi Arabia.
Carbapenem-resistant Acinetobacter baumannii is an urgent threat worldwide. This bacterium is associated with high morbidity and mortality, with limited available treatment options. Here, we report ...the draft genome sequences of five carbapenem-resistant Acinetobacter baumannii isolates from human samples.
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