Extended-Spectrum Beta-Lactamases Producing Pseudomonas aeruginosa Isolated From Patients With Ventilator Associated Nosocomial Infection

Background: Ventilator-associated infections caused by extended-spectrum beta-lactamases (ESBL)-producing Pseudomonas aeruginosa leads to severe complications. Objectives: This research evaluated ESBL-producing P. aeruginosa carrying integron class 1 and class 2 isolated from patients with ventilator-associated nosocomial infections, admitted in to the intensive care unit (ICU) of eighteen hospitals in the north of Iran. Methods: The antibiotic susceptibility test was performed using minimum inhibitory concentration (MIC). The ESBL isolates were tested by the polymerase chain reaction (PCR) for the presence or absence of CTX, VEB, SHV, GES, and integron class 1 and 2 genes. Results: Out of the total of 205 patients at the ICUs with nosocomial infections (NIs), ESBL-producing P. aeruginosa was responsible for 14.63% of NIs. The prevalence of ventilator-associated infection for ventilator-associated pneumonia (VAP) was (25 patients) 83.33%, also 16.6% (five patients) had sepsis due to VAP. Distribution of CTX, VEB, SHV, and GES genes was 13 (43.33%), four (13.33%), 26 (86.66%), and zero (0%), respectively. The strains carrying integron class 1 and class 2 were 26 (86.66%) and two (6.66%), respectively. Regarding ESBL genes, six types of strains were observed to carry these genes. Conclusions: The presence of P. aeruginosa isolates containing different ESBL genes isolated from patients admitted to ICUs of eighteen hospitals, signifies the importance of employing antimicrobial stewardship in hospitals for avoiding unnecessary antibiotics prescription for empiric therapy, especially for critically ill patients at the ICUs.