[Aminoglycoside resistance in Enterobacteriaceae originated in a gynecology-obstetrical hospital: a survey for 16s rRNA methylases: ArmA, RmtB and RmtC].

We examined the resistance of 2359 clinical isolates of Enterobacteriaceae to gentamicin, amikacin, netilmicin and neomycin by the disc-diffusion assay. The isolates originated from female-patients and newborn infants in a gynecology-obstetrical hospital in Warsaw, Poland. Isolates from adults predominated. Most of the isolated bacteria were considered non-pathogenic, colonization flora. The majority (above 95%) of the isolates were sensitive to all of the tested aminoglycosides. Forty five (1,90%) isolates were resistant to one or more agents. In this group, E. coli was prevalent (73,33%). As little as 14 isolates had no growth inhibition around the gentamicin disc (10 mcg) (contact-growth). MICs of seven isolates ranged from 256 to 1024 (mcg/ml) of the tested agents. One isolate had MIC 1024 for amikacin and kanamycin. All the contact-growth isolates were examined for genes encoding for TEM, SHV and CTX-M beta-lactamases, and genes armA, rmtB and rmtC for 16S rRNA methylases reported in Europe. All of them produced TEM enzyme while SHV and CTX-M was expressed by one and two isolates respectively. None of the tested 16S rRNA methylases was detected. Our results show the low carriage of the aminoglycoside-resistant Enterobacteriaceae in healthy pregnant-women and most probably their sexual partners. Our findings may argue that production of the 16S rRNA methylases is still limited to patients with a long-term antibiotic-therapy in regular hospitals rather than to non-hospitalized population in Poland.