Susceptibility to beta-lactams and quinolones in Enterobacteriaceae isolated from UTIs in outpatients.

MARTIN MARCHISIO; AYELEN PORTO; ROMINA JORIS; MARINA RICO; MARIA ROSA BARONI; JOSE DI CONZA

BRAZILIAN JOURNAL OF MICROBIOLOGY

SOC BRASILEIRA MICROBIOLOGIA

Año: 2015 vol. 46 p. 1155 - 1159

1517-8382

The antibiotic susceptibility profile was evaluated in 71 Enterobacteriaceae isolates collected from outpatient urine cultures during July 2010 in two health institutions from Santa Fe, Argentina. The highest antibiotic resistance rates were observed to ampicillin (69%) (AMP), trimethoprim/sulfamethoxazole (33%) (TMS) and ciprofloxacin (25%) (CIP). Meanwhile, 21% isolates were resistant to 3 or more tested antibiotics families. Thirty integron-containing bacteria (42.3%) were detected and a strong association with TMS resistance was found. Third generation cephalosporin resistant was detected in only one Escherichia coli isolate and it was characterized as blaCMY-2 carrier. No plasmid-mediated quinolone resistance (PMQR) was found. Fluoroquinolone resistance was due to alterations in QRDR regions. Two mutations in GyrA (S83L, D87N) and one in ParC (S80I) were observed in all CIP-resistant E. coli. It was determined the main phylogenetic groups in E. coli isolates. Minimum Inhibitory Concentration (MIC) values to nalidixic acid (NAL), levofloxacin (LEV) and CIP were determined for 63 uropathogenic E. coli isolates being the MIC50 of 4 µg/ml, 0.03125 µg/ml and 0.03125 µg/ml while the MIC90 values of 1024 µg/ml, 64 µg/ml and 16 µg/ml, respectively. Association between phylogenetic groups A and B1 with fluoroquinolone resistance was observed. These results suggest that it would be important to aware about the potential risk associated with empirical treatment with both antibiotic families.