A study on susceptibility patterns, resistance mechanisms and cross- resistances of antibiotics against Pseudomonas aeruginosa in a teaching hospital at Puducherry

Abstract

, a gram negative bacteria causes lung and nosocomial infections, mostly infect the body after surgery or invasive techniques. There has been a increasing prevalence in drug resistant variants in the recent years. 1. To determine the antibiotic susceptibility patterns of ; 2. To assess the antibiotics used against and the cross-resistence pattern existing between them; 3. To evaluate the possible resistance mechanisms of by phenotypic techniques.Thirty six consecutive, nonduplicate isolates were collected between January to July in the year 2018 from the hospital pus samples. The isolates showed synthesis of pyocyanin and a oxidase positive reaction. Kirby bauer’s disc diffusion method (HIMEDIA). was used for assessing the sensitivity of drugs. Disk approximation test was done to check the prevalence of inducible β-lactamases. Modified Hodge test was done to assess the metallo-β-lactamase activity. Double disk synergy method had been preferred to evaluate the extended-spectrum beta-lactamase (ESBL) activity. The most sensitive antibiotic was found to be ciprofloxacin which is followed by amikacin and ceftazidime (p < 0.05). 36% of the samples were resistant to more than one antibiotic groups. Cross-resistance was observed between the antibiotics. 53% of the samples had Inducible β-lactamases. Eighty percent of the samples which were non-resistant to ceftazidime showed positive reaction for inducible beta-lactamase. 2% isolates by DDS method showed the presence of ESBLs. The study samples did not show the presence of Metallo-β-lactamases.Strict adherence to the recent trend of “reserve drugs” concept and minimizing the misuse of antibiotics can bring down the drug resistance and morbidity. The addressal of irrational and inappropriate use of antimicrobials among the clinician is the need of the hour.