Investigation of Metallo Beta Lactamases and Oxacilinases in Carbapenem Resistant Acinetobacter baumannii Strains Isolated from Inpatients

Abstract

Acinetobacter baumannii strains are non-fermenting aerobic Gram-negative bacteria that play an important role in hospital infections. Difficulties in the treatment and control of this growing threat make this pathogen an important health problem (1).Resistance to beta-lactam antibiotics is widespread among Acinetobacter strains. Plasmid-mediated metallo beta-lactamases Background: Resistance to beta-lactam antibiotics is widespread among Acinetobacter strains. Plasmid-mediated metallo beta lactamases (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 in Turkey in increasing rates. In our country, besides the OXA 51-like enzyme which is inherent in A. baumannii strains, OXA 58-like and OXA 23-like carbapenemases producing strains have also been widely detected. In addition, Verona Imipenemase (VIM) and (IMP)-type MBL have been reported in some centers. Aims: The aim of our study was to investigate the presence of carbapenemases in Acinetobacter strains isolated from hospitalized patients in Edirne. Study Design: Cross-sectional study. Methods: A total of 52 imipenem-resistant A. baumannii strains isolated between January and March 2013 were investigated. The presence of MBL was described phenotypically by the combined disk diffusion test (CDDT), double disk synergy test (DDST), MBL Etest (only performed in 28 strains) and modified Hodge test. bla IMP , bla VIM , bla GIM , bla SIM , bla SPM genes and bla OXA-23 , bla OXA-51 , bla OXA-40 , bla OXA-58 genes were investigated by multiplex polymerase chain reaction (PCR). The blaNDM-1 gene was determined by PCR. Results: By modified Hodge test, 50 strains (96%) were found to be MBL positive. Positivity of MBL was 21% by both CDDT (0.1 M EDTA) and DDST. Twenty-four of 28 strains (85.7%) were positive by MBL E-test. OXA 23-like and OXA 51-like carbapenemases were detected in all strains, but OXA 58-like and OXA 40-like carbapenemases-producing A. baumannii were not detected. Also, MBL genes were not detected by genotypic methods. Conclusion: Only OXA 23-like carbapenemase was responsible for carbapenem resistance in carbapenemresistant Acinetobacter strains in Edirne. The MBLproducing Acinetobacter strain is not yet a problem in our hospital. MBL resistance was found by phenotyping tests, which must be confirmed by genotypic methods; multiplex PCR tests can be easily used for screening MBL.

Studies of common antibiotic resistance-associated genes of Acinetobacter baumannii

“…2). Such prevalence is in line with the findings of other studies [9,10]. However, compared to others, the sample size in our study was relatively small; therefore, the study should be expanded to obtain more statistically significant data.…”

“…The results of the antibiotic sensitivity test of eight β-lactam antibiotics, as indicated in 19/58 samples, revealed that three antibiotics, CRO, FEP (a cephalosporin), and Screening of the 58 samples (52 DNA and established multiplex PCR showed that the presen e (47/58, 81%), following by OXA-23: (63.8%, 37/58) (1.7%), the lowest, was found in only one sample (Fig with the ndings of other studies [9,10]. However, c size in our study was relatively small; therefore, the obtain more statistically signi cant data.…”

Distribution of Aminoglycoside Resistance Genes Among Acinetobacter Baumannii Strains Isolated From Burn Patients in Tehran, Iran

“…Several sudden outbreaks of the bacteria are reported annually from hospitals around the world, indicating the importance of the bacteria and the need for a suitable plan to prevent infection, particularly by resistant strains. Many studies conducted in hospitals during the sudden outbreaks, revealed that hospital environments had been the source of infection in most cases (19). Various studies showed that Acinetobacter could survive for 16 weeks on dry surfaces of an environment; and this is considered as an alarm for its treatment because the isolates of A. baumannii could be isolated repeatedly from all various surfaces, indicating its high adaptability to incompatible environmental conditions.…”

Evaluation of metallo-beta-lactamase production in multiple antibiotic-resistant Pseudomonas spp. and Acinetobacter baumannii strains

“…K€ uç€ ukbasmaci et al [30] did not detect any MBL resistance gene by multiplex PCR in any one of the 51 isolates of P. aeruginosa. Aksoy et al [31] did not detect any MBL gene in 52 IMP resistant A. baumannii isolates but reported OXA-23-like and OXA-51-like resistance genes. In a study from northern Turkey, among 100 P. aeruginosa isolates studied by Ozgumus et al [32], VIM-type MBL was detected in one strain, IMP-1 type MBL was detected in nine strains, and clonal analysis of the IMP-1 type positive isolates revealed that all the strains were clonally related.…”