Detection Rate of Metallo-β-Lactamase-Expressing Genes; blaVIM-1, blaVIM-2 and blaSPM-1 in Pseudomonas aeruginosa Isolates

Imipenem-resistant Pseudomonas aeruginosa is an organism expressing metallo-β-lactamase (MBL) enzyme, and is a serious agent of hospital infection holding a serious universal therapeutic challenge. Carbapenems are potent options for the treatment of P. aeruginosa infections. The rate of MBLs expression has been variable among imipenem-resistant P. aeruginosa isolates. In the present study, we investigated the presence of MBL in the clinical isolates of P. aeruginosa.
A total of 60 P. aeruginosa isolates were obtained from Kerman hospitals during 2014-2015. The antibiotics susceptibility was assessed using disk diffusion test. MBL positivity in P. aeruginosa was investigated using double disk synergy test (DDST) and polymerase chain reaction (PCR) with amplification of blaVIM-2, blaVIM-1 and blaSPM-1.
From 60 P. aeruginosa isolates, 28 (46.6%) were imipenem-resistant. Among these, 17 (60.7%) were identified as MBL-producing P. aeruginosa isolates using DDST. Results of PCR test demonstrated the existence of 8 (28.5%) P. aeruginosa, producing blaSPM-1.
The frequency of blaSPM-1-producing P. aeruginosa isolates from Kerman Hospitals was relatively high. Therefore, it is recommended that the distribution of MBL-mediated resistances be managed.