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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 bla CMY-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.

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Background: Extended spectrum beta-lactamase (ESBL) producing bacteria have emerged worldwide. There are a few reports on the prevalence of ESBL producing bacteria in Japanese teaching hospitals. In order to clarify if occurrence had been increased, we conducted retrospective study.Methods & Materials: All the patients who had bacterial culture test in our hospital from the year 2006 to 2015 were enrolled. ESBL production was confirmed by using double-disk synergy test. Bacterial culture was performed by BML Inc, Kawagoe, Japan. Prevalence of ESBL producing bacteria was compiled by strain basis. If the strain was detected more than twice from same type of specimen from one patient, they were counted as one strain. The local ethical committee approved the study.Results: 1. Increase of ESBL-producing strains and species. Forty-two ESBL producing strains were detected in the year 2005. They increased continuously and significantly to 216 strains in 2015. Among them, E.coli was the most dominant (56%). K.pneumoniae (22%) and P. mirabilis (22%) were secondly dominant in 2006. In 2015, E.coli increased to79%. K.pneumoniae, P.mirabilis and K. oxytoca were 32,11,1%, respectively. More than 90% of cases stayed as carriers, not showing serious infection by ESBL producing bacteria.2. Difference of age groups During the period, number of ESBL producing bacteria increased from two to 75 strains in children aged zero to nine. Senior patients aged >70 also recorded increase from 23 to 85 strains.3.Difference among specimens Sources of ESBL producing bacteria were urine (52%), sputum (24%), stool (21%) and blood (3%) in 2006. In the year 2015, the ratio of stool increased to 44%, urine, sputum, blood were 39, 13, 4%, respectively.In order to prevent outbreak, our hospital performs screening culture every other week for resistant bacteria to all neonatal care unit patients since 2004. On the other hand for adults, culture is ordered mostly in case with infectious symptoms. Both groups showed incease of ESBL producing bacteria strains. This result suggests occurrence of ESBL producing bacteria is increasing.Conclusion: ESBL producing bacteria had been increased in the last ten years, especially in newborns and senior patients.