Comparison of factors contributing to drug resistance and infection severity in Pseudomonas aeruginosa isolates among COVID-19 and non-COVID-19 patients.

BACKGROUND

SARS-CoVs increase susceptibility to bacterial co-infections, with Pseudomonas aeruginosa frequently detected in COVID-19 patients. Factors such as drug resistance, mobile genetic elements, and biofilm formation further complicate these infections. This study compared these characteristics in P. aeruginosa isolates from COVID-19 and non-COVID-19 patients.

METHODS

During a one-year study, 125 P. aeruginosa isolates were collected from COVID-19 patients (37 isolates) and non-COVID-19 patients (88 isolates). They were identified using conventional microbiological methods. Antimicrobial resistance patterns and multidrug-resistant (MDR) isolates were determined according to CLSI guidelines and MDR definitions. Biofilm formation was evaluated using a microtiter plate assay, and the presence of genes related to plasmid-mediated quinolone resistance (PMQR), integrons, and biofilm formation was determined by polymerase chain reaction (PCR).

RESULTS

The highest resistance and susceptibility among the COVID-19 and non-COVID-19 groups were observed with imipenem (51.4% vs. 42%) and cefepime (73% vs. 64.8%), respectively. Quinolones resistance ranged from 32 to 36%. Overall, 54 isolates (43.2%) were MDR, with colistin resistance found in 50% and 37.5% of MDR isolates from COVID-19 and non-COVID-19 patients, respectively. Isolates from COVID-19 patients also showed stronger biofilm-forming ability. Among PMQR genes, only aac(6')-Ib-cr was detected (47.2% of isolates). The prevalence of aac(6')-Ib-cr, class 1 integron, and pelF genes was significantly higher in isolates from COVID-19 patients.

CONCLUSION

Resistance to commonly used antibiotics from different classes, along with biofilm formation, class 1 integron, aac(6')-Ib-cr, and biofilm-associated genes, were higher in COVID-19 isolates, likely contributed to the greater severity of infections in this group.