Abstract The antibiotic susceptibility profile was evaluated in 71 Enterobacteriaceae isolates obtained from outpatient urine cultures in July 2010 from two health institutions in Santa Fe, Argentina. The highest rates of antibiotic resistance were observed for ampicillin (AMP) (69%), trimethoprim/sulfamethoxazole (TMS) (33%), and ciprofloxacin (CIP) (25%). Meanwhile, 21% of the isolates were resistant to three 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 resistance was detected in only one Escherichia coli isolate, and it was characterized as a blaCMY-2 carrier. No plasmid-mediated quinolone resistance (PMQR) was found. Resistance to fluoroquinolone in the isolates 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 to be the main phylogenetic groups in E. coli isolates. Minimum Inhibitory Concentration (MIC) values against nalidixic acid (NAL), levofloxacin (LEV), and CIP were determined for 63 uropathogenic E. coli isolates as MIC50 of 4 μg/mL, 0.03125 μg/mL, and 0.03125 μg/mL, respectively, while the MIC90 values of the antibiotics were determined as 1024 μg/mL, 64 μg/mL, and 16 μg/mL, respectively. An association between the phylogenetic groups, A and B1 with fluoroquinolone resistance was observed. These results point to the importance of awareness of the potential risk associated with empirical treatment with both the families of antibiotics.

The presence of class 1, 2, and 3 integrons was investigated in four pediatric isolates of Salmonella enterica ser. Typhimurium (S. Typhimurium). A class 1 integron was detected in one S. Typhimurium strain, the only one that also showed resistance to various aminoglycoside antibiotics. This integron, called InJR06, and the aminoglycoside resistance determinants were located in pS06, a large (≥ 55 kb) conjugative plasmid. A single mobile cassette (encoding the aminoglycoside adenylyltransferase ANT(3´´)-Ia) was detected in the variable region of InJR06, while the architecture of the attI1 and attC sites was conserved.

Se averiguou a presença de integrones de classe 1, 2 e 3 em quatro isolamentos pediátricos de Salmonela enterica ser. Typhimurium (S. Typhimurium). Um integrón de classe 1 se pôde detectar em uma cepa de S. Typhimurium, a única que além disso apresentava resistência a vários antibióticos aminoglucósidos. Este integrón, chamado InJR06, e os determinantes de resistência a aminoglucósidos se localizaram em pS06, um plásmido conjugativo de tamanho grande (≥ 55 kb). A análise da região variável de InJR06 mostrou que um cassete genético codifica a aminoglucósido adeniltransferasa ANT(3´´)-Ia e que a arquitetura dos lugares attI1 e attC está conservada.

Se investigó la presencia de integrones de clase 1, 2 y 3 en cuatro aislamientos pediátricos de Salmonella enterica ser. Typhimurium (S. Typhimurium). Un integrón de clase 1 se detectó en una cepa de S. Typhimurium, la única que además presentaba resistencia a varios antibióticos aminoglucósidos. Este integrón, llamado InJR06, y los determinantes de resistencia a aminoglucósidos se localizaron en pS06, un plásmido conjugativo de tamaño grande (≥ 55 kb). El análisis de la región variable de InJR06 mostró que un casete génico codifica la aminoglucósido adeniltransferasa ANT(3´´)-Ia y que la arquitectura de los sitios attI1 y attC está conservada.