In vitro activity of penicillins, cephalosporins, aminoglycosides and aztreonam against clinical isolates of fluoroquinolone - resistant [FQR] aerobic gram-negative bacilli

ABSTRACT

A retrospective analysis of antibiotic susceptibility pattern of 634 clinical isolates of aerobic gram-negative bacilli isolated from urine, sputum, ear discharge and wounds was performed. The bacteria consisted of 270 isolates of Escherichia coli, 265 Pseudomonas aeruginosa, 58 Klebsiella sp., and 41 isolates of Proteus sp. Out of these 634 isolates, 191 [30.1%] were found resistant to three commonly used fluoroquinolones that is ciprofloxacin, ofloxacin and enoxacin. Out of 270 isolates of Escherichia coli, 104 [38.5%] were fluoroquinolone-resistant [FQR] while 59/265 [22.3%] isolates of Pseudomonas aeruginosa, 20/58 [34.5%] isolates of Klebsiella sp., and 8/41 [19.5%] isolates of Proteus sp. were found FQR. Cummulative susceptibility of these 191 FQR isolates to other eleven antibiotics was; amoxycillin 9.4%, coamoxy-clav 23%; coampi-sulbac 30.4%; gentamicin 68.1%; tobramycin 70.2%; cephradine 16.7%; cefaclor 25.6%; ceftizoxime 49.2%; ceftazidime 48.7%; cefuroxime 36.7% and aztreonam 26.2%