Phenotypic and Molecular Survey of Metallo-beta-lactamase-producing Pseudomonas aeruginosa Isolated from Patients with Nosocomial and Non-Nosocomial Infections.

BACKGROUND: Resistance to antimicrobial agents in Pseudomonas aeruginosa (P. aeruginosa) including carbapenems is a prominent problem in patients. Aim of this study is surveying metallo-beta-lactamase (MBL)-producing P. aeruginosa isolated from patient specimens with nosocomial and non-nosocomial infections in Kurdistan province, Iran.

MATERIALS AND METHODS: In total, 146 Pseudomonas spp. were collected (December 2015 to August 2017). P. aeruginosa isolates were detected by phenotypic and polymerase chain reactions (PCR) of gyrB gene. Combination disk (CD) phenotypic test was used for identification of MBL-producing strains and PCR was applied for identification of blaIMP and blaVIM genes in P. aeruginosa. Sensitivity and specificity of phenotypic tests were calculated as well. Fisher's exact test and logistic regression were used for data analysis (p≤0.05).

RESULTS: A total of 134 (91.78%) and 133 (91.09%) P. aeruginosa were detected using PCR and the phenotypic test, respectively. Fifty six (41.79%) clinical isolates were isolated from patients with nosocomial infection. CD test proved that 67 out of 134 (50%) P. aeruginosa isolates were positive for MBL, of which 11 (8.20%) carried blaIMP gene. No significant relationship was found between MBL-producing P. aeruginosa and blaIMP genes; as well as between MBL-producing P. aeruginosa and blaIMP genes with age, sex, city of residence, inpatient/outpatient, and specimen's type (p≥0.05).

CONCLUSION: Presence of MBL-producing P. aeruginosa strains and blaIMP genes were proved in this study; thus more precaution should be taken in administration of carbapenem antibiotics to patients.