Prevalence of overexpressed resistance nodulation division (RND) efflux pumps of Pseudomonas aeruginosa causing nosocomial infections in several hospitals in Ho Chi Minh City

Pseudomonas aeruginosa is a prevalent nosocomial pathogen known for its extensive antibiotic resistance. The overexpression of antibiotic efflux systems plays crucial role in the resistance patterns of this bacterium. Nevertheless, studies on the prevalence of efflux pump overexpression in P. aeruginosa in Vietnam remain limited. From May to July 2023, all strains suspected to be P. aeruginosa were collected from inpatents at the University Medical Center of Ho Chi Minh City, and Le Van Thinh Hospital, Ho Chi Minh City, Vietnam. After identification, the antibiotic susceptibility of these isolates were determined. Finally, the prevalence of overexpression of the MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY- OprM efflux systems were determined using the phenotypic method. The relationship between certain efflux pump overexpression and sampling sites or the antibiotic resistance profiles of these strains was analyzed using the Chi-squared test. Sixty isolated P. aeruginosa strains exhibited high rates of resistance to commonly used antibiotics, including ceftazidime (38.33%), cefepime (40.00%), meropenem (56.67%), imipenem (65.00%), gentamycin (41.67%), amikacin (31.67%), ciprofloxacin (45.00%), and levofloxacin (50.00%). The efflux pump MexEF-OprN was the most frequently overexpressed, found in 32/60 strains (53.33%), followed by MexCD-OprJ, which was overexpressed in 13/60 strains (21.67%). The overexpression of MexAB-OprM and MexXY-OprM were less common, detected in 6/60 strains (10.00%) and 3/60 strains (5.00%), respectively. MexEF-OprN overexpression was associated with the resistance patterns of these isolates. the current study was successful in determining the prevalence of efflux pump overexpression in clinical P. aeruginosa strains collected at multiple hospitals in Ho Chi Minh City.