Prevalence and Antibiotic Resistance Patterns of Metallo-Beta-Lactamase-Producing Pseudomonas aeruginosa Isolated from Patients in a Hospital in Zabol, Southeast of Iran

Treatment of infections caused by metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa (P. aeruginosa) is a major healthcare-associated concern. Therefore, the purpose of this study was to ascertain antibiotic resistance patterns and prevalence of MBL genes in clinical isolates of P. aeruginosa.

   In total, 90 non-repetitive clinical isolates of P. aeruginosa were collected from clinical specimens of patients who referred to Amir Al-Momenin hospital in Zabol, southeast of Iran, from January 2019 to November 2022. Antibiotic susceptibility patterns were determined according to CLSI guidelines. Combined disk test (CDT) was used to detect MBL-producing P. aeruginosa isolates. MBL genes (blaIMP, blaVIM, blaNDM, and blaSPM) were detected by PCR (polymerase chain reaction) method.

The isolates were mostly resistant to ceftriaxone (51.1%, 46 of 90) and gentamicin (43.3%, 39 of 90). Based on CDT results, 89.4% (17 of 19) of carbapenem-resistant isolates were MBL positive. In addition, MBL genes including blaVIM, blaIMP, and blaNDM were detected in 20% (18 of 90), 8.9% (8 of 90), and 5.6% (5 of 90) of the isolates, respectively.

Based on this study findings, the use of ceftriaxone and gentamicin should be restricted. In addition, MBL genes (blaVIM and blaIMP) seem to play a crucial role in the spread of carbapenem-resistant infections and the emergence of multidrug-resistant isolates, leading to antibiotic treatment failure.