Molecular identification of Pseudomonas aeruginosa and antibiotic resistance testing

Abstract

Pseudomonas aeruginosa is a Gram-negative bacillus considered an opportunistic pathogen, usually associated with nosocomial infections in immunocompromised patients. Among the infections caused, the most frequent are urinary tract infections, wound infections, pneumonia, and bacteremia. It has intrinsic and acquired resistance to antibiotics, due to the low permeability of its outer membrane, the overexpression of efflux pumps, and the production of enzymes that degrade the antibiotic. In this study, 61 samples of P. aeruginosa collected from the General Hospital “Dr. Aquiles Calles Ramírez" from the city of Tepic, which were phenotypically identified using the Vitek2 automated system. Subsequently, they were molecularly identified with the polymerase chain reaction technique, targeting the gyrB gene that codes for the B subunit of DNA gyrase. In 60 of the samples, amplification of the gyrB gene was obtained and only one, no amplification was observed. The results showed that infections caused by P. aeruginosa are more frequent in male patients, in age range of 41-60 years. Urine culture being the origin of the sample that most predominated. The sensitivity-resistance analysis to antibiotics showed that most of the strains are resistant to β-lactams, except for meropenem, which presented a high sensitivity in most of the strains, as well as in the case of ciprofloxacin, amikacin, and gentamicin.