Antibiotic sensitivity of Enterococcus species strains cultured from hospital and medical centre patients

摘要

The isolation of Enterococcus species bacteria from clinical materials has recently become quite a frequent procedure. These micro-organisms are frequently resistant to many antibiotics, thus they often create therapeutic problems. The purpose of our study was to analyse Enterococcus spp. occurrence in diagnostic materials taken from the patients of the State Clinical Hospital of the Medical University in Bydgoszcz and from patients treated in medical centres (ambulatory centres), and to evaluate the sensitivity of these bacteria to antibacterial drugs. The analysis encompassed 1002 enterococcal strains coming from clinical material and 209 strains from medical centre material. The identification of Enterococcus spp. was based on Slidex-Strepto-kit (Bio-Merieux) and API 20 Strep (Bio-Merieux) test results. Antibiotic sensitivity was evaluated by disk-diffusion method. Resistance to high aminoglycoside concentrations (500 mg/l - gentamycin and 2000 mg/l streptomycin) was evaluated on BHI (Brain-Heart-Infusion, Bio-Merieux) agar. Among 8 800 micro-organism strains isolated in 1995, 1 211 (13.8%) strains were classified as enterococci strains. 1 002 (82.7%) strains originated from hospital patients, 209 (17.3%) strains were isolated from out-patient patients. The total of 768 (63.4%) enterococci was isolated in monocultures out of which number 629 (81.9%) belonged to species E. faecalis, while 139 (18.1%) - to E. faecium. None of enterococci strains under study was resistant to glycopeptides. None of strains produced (-lactamase in nitrocefin test (cefinaze, BBL). Enterococci strains isolated from urine in high percentage were sensitive to nitrofurantoin; this pertained to both hospital patients (80.6%) and medical centre patients (93.4%). About 30% of enterococci isolated from hospital patients and about 7% strains from medical centre patients were resistant to high concentration of aminoglycosides.key words: Enterococcus spp, resistance to antibiotics, resistance to high level concentrations of aminoglycosides