Abstract

GUILLEN, Rosa et al. Molecular detection of extended spectrum beta-lactamase (esbl) in enterobacteria isolated in Asunción. Mem. Inst. Investig. Cienc. Salud [online]. 2016, vol.14, n.1, pp.8-16. ISSN 1812-9528.  https://doi.org/10.18004/Mem.iics/1812-9528/2016.014(01)08-016.

Extended spectrum beta-lactamases (ESBLs), are enzymes responsible for the hydrolysis of the beta-lactam ring and resistance to both cephalosporins and penicillins, except carbapenems, therefore inhibiting its therapeutics activity. Even though, detection of the phenotypic resistance mechanism by conventional methods is possible, only molecular methods allow identification of the gene responsible for the resistance. The objective of this retrospective study was to identify the blaCTX-M2, blaPER-2, blaSHV, blaTEM genes in ESBL-producing enterobacteriaceae isolates, recovered from clinical samples collected between July 2007 and April 2008, from two reference hospitals in Asunción, Paraguay. Molecular gene detection was performed by polymerase chain reaction using specifics oligonucleotides. Out of the tested 232 ESBL-producing isolates, 83% (n=192) carried at least one of the bla genes as follows; 49% (94/192) blaCTX-M2, 45% (86/192) blaSHV, 40% (77/192) blaTEM and 7% (13/192) blaPER-2. In the rest 17% (n=40) none of the genes included in this study was detected; in 47% (90/192) more than one gene was detected, resulting blaCTX-M2 + blaTEM + blaSHV as the most frequent combination in 32 isolates. The presence of blaCTX-M2, as the most frequent codifying genes of BLEE is in agreement with previous reports in Paraguay and Argentina. This is the first report of the presence of blaTEM and blaSHV circulating in Paraguay. It is of much importance the study of others codifying resistance genes, taking into account the emergence of other BLEE in the region, such as blaCTX-M15, predominantly with ceftazidimase activity.

Keywords : Extended-Spectrum Beta-Lactamase (ESBL); cephalosporin resistance; enterobacterias; Polymerase Chain Reaction (PCR).

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