Genetic fingerprinting and antimicrobial susceptibility profiles of Pseudomonas aeruginosa isolates from eye infections

Background: As Pseudomonas aeruginosa is known the most common etiologic agent in microbial keratitis associated with contact lens use, this study was designed to study the distribution and patterns of resistance to antimicrobial agents of keratitis isolates in Iran. In this study, also the suitability of enterobacterial repetitive intergenic consensus (ERIC)- PCR to rapidly type P. aeruginosa strains isolated from patients with keratitis was examined. Patients and methods: For this purpose, 57 clinically isolates of P. aeruginosa from keratitis patients referred to Farabi hospital were analyzed by antimicrobial susceptibility test using the disc diffusion method. Polymerase chain reaction with enterobacterial repetitive intergenic consensus primers (ERIC-PCR) was used to establish clonal relationship between the different isolates. Results: All the strains showed resistance to at least 4 antibiotics, but all were susceptible to fluoroquinolones. Multidrug resistance was found in two isolates (3.5%) which were resistant to more than one category of antibiotics including aminoglycoside (gentamicin) and B-lactam (cefazoline). ERIC-PCR produced 53 different ERIC fingerprints, 49 of which contained only 1 strain. Eight of the isolates had 100% similarity, forming four real clones but considering 85% similarity cut off between isolates, 8 clones containing 25 isolates (43.8%) could be considered. Conclusion: Fluoroquinolones appeared to be the most effective agent against ocular P. aeruginosa isolates. Comparison of ERIC-PCR profiles revealed a low level of similarity among the strains analyzed. ERIC-PCR seems to be an inexpensive, fast, reproducible, and discriminatory DNA typing tool for effective epidemiologic surveillance of P. aeruginosa isolates potentially transmissible between patients with ocular infections.