Detection of metallo-beta lactamases and oxacillinase genes in carbapenem-resistant Acinetobacter baumannii strains isolated in Morocco

Abstract

Introduction resistance to carbapenem is widespread among Acinetobacter baumannii (A. baumannii) strains. Metallo-beta lactamases enzymes (MBL) are responsible for carbapenem resistance, as are oxacillinases (OXA). In recent years, MBL producing carbapenem-resistant strains have been reported in the world and Morocco at increasing rates. Our study aimed to investigate the presence of carbapenemases in acinetobacter strains isolated from hospitalized patients in CHU Fez. Methods a total of 58 imipenem-resistant A. baumannii strains isolated from clinical samples were investigated. The presence of MBL was described phenotypically by the double-disk synergy test (DDST), MBL E-test, and modified Hodge test. The bla IMP , bla VIM , genes, and bla OXA-23 , bla OXA-51 genes were investigated by multiplex polymerase chain reaction (PCR). The blaNDM-1 gene was determined by simplex PCR. Results fifty-eight strains were resistant to imipenem (98%), the modified Hodge test (MHT) was positive for 58 strains (100%), 47 strains (82%) were found to be positive for MBL by the test of double-disk synergy (DDST), 58 strains (100%) were positive by E-test MBL. The OXA 51 gene was detected in all strains, and the OXA 23 gene was detected in 53 strains (91%). In addition, the MBL genes were not detected by genotypic methods. Conclusion the OXA-23 and OXA-51 carbapenemases type are responsible for the resistance to carbapenems in A. baumannii resistant to carbapenems in our establishment. Resistance to carbapenems by MBL enzymes has been found by phenotypic tests, which must be confirmed by genotypic methods; and solicit other MBL genes.

Application of nanopore sequencing to identify antimicrobial resistance genes, mobile genetic elements and virulence factors in clinical isolates

“…Three out of five isolates of A. baumannii co-harboured carbapenemase and extended spectrum beta-lactamase genes. This occurrence of double or multiple carbapenemase genes in a single isolates is a finding demonstrated in other studies [22] as well as co-existence of carbapenemase and extended-Spectrum β -Lactamase genes in single isolate [24]. One gram-positive isolate harboured carbapenems hydrolyzing oxacillinase which has been described elsewhere [25].…”

“…other studies [22] as well as co-existence of carbapenemase and extended-Spectrum β-Lactamase genes in single isolate [24]. One gram-positive isolate harboured carbapenems hydrolyzing oxacillinase which has been described elsewhere [25].…”

Karbapenem dirençli Pseudomonas ve Acinetobacter türlerinde MBL üretiminin saptanması ve risk faktörlerinin değerlendirilmesi.

“…Deep tracheal aspirates (20) and wound tissue specimens (17) made up the majority of samples 31%, and 26%, respectively; specimens of urine accounted for 18% of blood 11%, of abscess 3%, of sputum 3%, CSF 3%, of nasal swab 2%, of catheter tip 2%, of ear drainage 2%. Acinetobacter spp.…”

“…However, as adjunct tests, simple phenotypic tests can be used to detect such species, particularly diffusion or dilution methods based on increasing synergism between MBL inhibitors (including either EDTA or thiol compounds) and oximinocephalosporins or carbapenems. Phenotypic tests such as double disk synergy (DDS) and E-MBL strip tests consisting of EDTA-IMP and EDTA and 2-mercaptopropionic acid have been used DDS tests were followed by EDTA and imipenem-EDTA disc-diffusion microdilution methods both of which were confirmed to be reliable in detecting MBLs in carbapenem resistant Pseudomonas and Acinetobacter species [18][19][20][21][22]. Walsh Discrepancies in these studies were considered to result from the differences in the numbers of isolates examined [16,18,[22][23][24][25].…”

Acinetobacter baumannii Carbapenemase Producers in Morocco: Genetic Diversity

“…In North Africa, more specifically in Morocco, the presence of the carbapenemase gene in A. baumannii has been detected. Except for sporadic studies [ 7 , 8 ], we are not aware of any other studies on the characterization of carbapenemase genes in A. baumannii in Morocco.…”