Genetic diversity of OXA-51-like genes among multidrug-resistant Acinetobacter baumannii in Riyadh, Saudi Arabia
ABSTRACT We explore the genetic diversity of class D oxacillinases, including OXA-23, -24 (-40), -58 and, particularly, the intrinsic OXA-51-like genes, among multidrug-resistant (MDR) Acinetobacter baumannii strains from inpatients at a tertiary care hospital in Riyadh, Saudi Arabia. Sequence-based typing (SBT) of the OXA-51-like gene was carried out on 253 isolates. Selected isolates (n = 66) were subjected to multilocus sequence typing (MLST). The polymerase chain reaction (PCR) typing results showed that all isolates (n = 253) contained the OXA-51-like and OXA-23 genes. However, the OXA-58 gene was detected in five isolates. Further, none of the isolates had the OXA-40 (identical to the OXA-24) gene. SBT revealed a high OXA-51-like genotypic diversity and showed that all isolates were clustered into four main groups: OXA-66 (62.3 %), followed by OXA-69 (19.1 %), OXA-132 (7.6 %) and other OXA-51-like genes (10.3 %), including OXA-79, -82, -92, -131 and -197. MLST revealed four main sequence types (STs), 2, 19, 20 and 25, among the isolates, in addition to six isolates with newly designated ST194-ST197 singletons. Further, a high prevalence (81.4 %) of OXA-66 and OXA-69-like genes in A. baumannii was identified. More studies are essential in order to explore the molecular mechanisms that confer carbapenem-resistant phenotypes for A. baumannii isolates and to investigate the genetic diversity of other OXA-D genes.
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- " CC . The detection of six novel STs supports the notion that A . baumannii is diverse in clonal origins and / or is undergoing clonal expansion continuously . Due to the close proximity of Kuwait to other countries in the Gulf region , it is not surprising to detect common STs : ST - 2 and ST - 25 have been previously identified in Saudi Arabia ( Aly et al . , 2014 ) and in Yemen ( Bakour et al . , 2014 ) . Moreover ; ST - 2 is known as an endemic strain in European countries including Italy and Spain ( Villalón et al . , 2011 ; Mezzatesta et al . , 2014 ) . We also detected the novel international CC32 with known epidemic potential ( Da Silva et al . , 2014 ) . It has been shown that strains assi"
ABSTRACT: Acinetobacter baumannii is one of the most important opportunistic pathogens that causes serious health care associated complications in critically ill patients. In the current study we report on the diversity of the clinical multi-drug resistant A. baumannii in Kuwait by molecular characterization. One hundred A. baumannii were isolated from one of the largest governmental hospitals in Kuwait. Following the identification of the isolates by molecular methods, the amplified blaOXA-51-like gene product of one isolate (KO-12) recovered from blood showed the insertion of the ISAba19 at position 379 in blaOXA-78. Of the 33 multi-drug resistant isolates, 28 (85%) contained blaOXA-23, 2 (6%) blaOXA-24 and 6 (18%) blaPER-1 gene. We did not detect blaOXA-58, blaVIM, blaIMP, blaGES, blaVEB and blaNDM genes in any of the tested isolates. In 3 blaPER-1 positive isolates the genetic environment of blaPER-1 consisted of two copies of ISPa12 (tnpiA1) surrounding the blaPER-1 gene on a highly stable plasmid of ca. 140-kb. MLST analysis of the 33 A. baumannii isolates identified 20 different STs, of which 6 (ST-607, ST-608, ST-609, ST-610, ST-611 and ST-612) were novel. Emerging STs such as ST15 (identified for the first time in the Middle East), ST78 and ST25 were also detected. The predominant clonal complex was CC2. PFGE and MLST defined the MDR isolates as multi-clonal with diverse lineages. Our results lead us to believe that A. baumannii is diverse in clonal origins and / or is undergoing clonal expansion continuously while multiple lineages of MDR A. baumannii circulate in hospital wards simultaneously.Frontiers in Microbiology 07/2015; 6(743). DOI:10.3389/fmicb.2015.00743 · 3.99 Impact Factor
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- "XA - 23 in particular ) are the dominant carbapenemases in this species , as reported elsewhere in the world ( Walther - Rasmussen & Høiby , 2006 ; Gordon & Wareham , 2010 ) . For the intrinsic OXA - 51 , OXA - 66 appears to be the major OXA - 51 - like gene in the Kingdom , consistent with reports from the USA , South America , Turkey and China ( Aly et al . , 2014 ) . VIM has also been documented in A . baumannii from Saudi Arabia , similar to many reports from the Asia Pacific region and Latin America ( Fritsche et al . , 2005 ) ."
ABSTRACT: Resistance to β-lactams among Gram-negatives is a worldwide issue. Increased prevalence of extended spectrum β-lactamase (ESBL)-producers and the dissemination of carbapenem resistance genes are particularly concerning. ESBL-producing strains are common in the Kingdom of Saudi Arabia particularly among the Enterobacteriaceae and carbapenem resistance is on the increase especially among the non-fermenters. β-lactamase production is a major mechanism of resistance to these agents and although β-lactamase-producing strains have been documented in the Kingdom, relatively few reports characterised the molecular basis of this production. Nevertheless, available data suggest that CTX-M (CTX-M-15 in particular) is the predominant ESBL in Enterobacteriaceae with SHV being also prevalent in Klebsiella pneumoniae. Carbapenem resistance in the latter is mainly due to OXA-48 and NDM-1. In Pseudomonas aeruginosa, VEB-like enzymes are the most common ESBLs and VIM is the prevalent metallo-β-lactamase. OXA-10 extended-spectrum enzymes are also frequent. PER and GES ESBLs have been reported in Acinetobacter baumannii and oxacillinases (OXA-23 in particular) are the dominant carbapanamases in this species. Copyright © 2014, the Society for General Microbiology.Journal of Medical Microbiology 11/2014; 64(Pt_2). DOI:10.1099/jmm.0.077834-0 · 2.25 Impact Factor
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ABSTRACT: Purpose: The aim of this study was to investigate the molecular support of resistance to carbapenems, aminoglycosides, and fluoroquinolones in Acinetobacter baumannii clinical isolates collected from Yemen hospital. Methods: Three A. baumannii were isolated in February 2013 from three patients hospitalized at Al-Thawra University Hospital in Sana'a, Yemen. Antibiotic susceptibility testing was performed using the disk diffusion and E-test methods. Carbapenemase production was carried out by the modified Hodge test (MHT) and imipenem-ethylenediaminetetraacetic acid (EDTA) methods. Carbapenem, aminoglycoside, and fluoroquinolone resistance determinants were studied by polymerase chain reaction and sequencing. The epidemiological relatedness of the three strains was studied using multilocus sequence typing (MLST). Results: The isolates were resistant to almost all antibiotics tested with very high imipenem, amikacin, and ciprofloxacin minimum inhibitory concentrations (>32, >256, and >32 mg/L, respectively). The microbiological tests showed that the three A. baumannii were MHT positive, besides, the activity of β-lactamases was not inhibited by EDTA. All the three isolates contained the naturally occurring bla(OXA-51)-like gene and the bla(OXA-23)-like carbapenemase-encoding gene. The 16S rRNA methylase armA gene was detected in the three isolates. In addition, screening for genes encoding the aminoglycoside-modifying enzymes (AMEs) demonstrated that one isolate contained the acetyltransferase gene aac(6')-Ib. Fluoroquinolone resistance was associated with a single mutation Ser83Leu in the quinolone resistance determining region of the gyrA gene in all isolates. The MLST showed that the sequence type (ST) obtained corresponds to ST2 for the three strains. Conclusions: Here we report the first identification of multidrug-resistant A. baumannii isolates harboring the bla(OXA-23)-like gene, AMEs [aac(6')-Ib], and the 16S rRNA methylase (armA) in the Yemen hospital.Microbial drug resistance (Larchmont, N.Y.) 06/2014; 20(6). DOI:10.1089/mdr.2014.0018 · 2.49 Impact Factor