| Popis: |
Background: Pseudomonas aeruginosa is an opportunistic pathogen involved in number of hospital acquired infections such as catheter-associated urinary tract infections, bacteremia, septicemia, skin infections and ventilator-associated pneumoniae. Biofilm formation is an important trait implicated in chronic infections, such as cystic fibrosis and chromic pulmonary obstruction. Method: A total of 266 isolates were collected from the Armed Forces Institute of Pathology (AFIP). Antibiotic susceptibility was assessed by double disk synergy testing. ESBL and Modified Hodge testing was performed for phenotypic confirmation of carbapenemases. Molecular screening of the genes was done by PCR. Micro-dilution broth method was used to determine minimum inhibitory concentrations of antibiotics. Biofilm formation was done by micro-titer plate assay. Results: Overall, 20% of the P. aeruginosa isolates were extensively drug resistant (XDR-PA) and 25% were multi-drug-resistant (MDR-PA). Likewise, 43% of the isolates were ESBL producers and carbapenemase production was detected in 40% of the isolates. Molecular analysis confirmed occurrence of different resistant factors in ESBL positive isolates; 67% carried bla-TEM, 62% bla-CTXM-15, 41% bla-SHV, 34% bla-CTXM-14 and 33% bla-OXA-1. In addition, 68% of carbapenem-resistant isolates were positive for bla-NDM-1, 25% for bla-OXA-48 and 22% for bla-KPC-2. Biofilm formation was tested for 234 isolates, out of which 28% were strong biofilm formers. Moderate and weak biofilm formers were 46% and 23% respectively. Overall, ciprofloxacin, levofloxacin and cefepime showed inhibitory effects on P. aeruginosa biofilms. Antibiotics in combination showed strong synergistic effects (ciprofloxacin & cefepime); while gentamicin and cefepime resulted into complete eradication of P. aeruginosa biofilm. Conclusion: We confirm strong synergistic effects of gentamicin and cefepime that completely eradicated P. aeruginosa biofilm. We further confirm inhibitory effects of ciprofloxacin, levofloxacin and cefepime on P. aeruginosa biofilms. |
