| Objective: The increasing prevalence of multi-drug resistant (MDR) strains is now a serious menace for public
health. The purpose of the study is to investigate the relationship between the variation of carbapenemases and
antibiotic resistance profile among A. baumannii strains isolated from Tabriz, North-west Iran.
Methods: A total of 127 A. baumannii isolates were obtained from two teaching hospitals in Tabriz, North-west
Iran. Multiplex PCR was performed for the detection of carbapenemase-encoding genes. Furthermore, the genetic
relationship of isolates was investigated by the enterobacterial repetitive intragenic consensus (ERIC)-PCR
technique.
Results: All isolates were resistant to carbapenem based on resistance to meropenem and imipenem. The frequency
of multidrug-resistant (MDR) and extensively drug-resistant (XDR) was equal to 74.80% and 33.07%
respectively. The most prevalent of MDR and XDR was related to patients up to 50 years (p < 0.05). The blaOXA-
23-like genes were the most predominant among tested isolates 82 (64.5%), followed by blaOXA-143-like, 54
(42.51%); blaOXA-72, 39 (30.7%). None of the isolates were positive for the blaOXA-58-like gene. There was a significant
relationship between the presence of the blaOXA-23 gene and the frequency of XDR strains (p < 0.01).
Based on ERIC-PCR, 88 isolates were clustered into seven groups, while the remaining 21 were as single isolates.
Most of the MDR isolates were related to B and C clusters (p < 0.05). The frequency of OXA-143 and OXA-72 was
significantly high in A and B clusters (p < 0.05). This is the first report of the high incidence of blaOXA-143 and
blaOXA-72 positive A. baumannii strains in Iran. The genetic relatedness of A. baumannii isolates was high, indicating
cross-transmission within hospitalized patients.
Conclusion: A high prevalence of MDR and XDR A. baumannii strains with new resistance mechanisms was
observed in our region. The incidence rate of OXA-type carbapenemases was different in the clusters classified by
ERIC -PCR typing. |