METHICILLIN RESISTANT STAPHYLOCOCCI - DISTRIBUTION IN CLINICAL SPECIMENS AND IN VITRO SUSCEPTIBILITY TO SOME ANTIBACTERIAL DRUGS

Methicillin/oxacillin resistant Staphylococci (MRS) cause high morbility and mortality. The aim of the present study is to determine the incidence rate of MRS among clinical specimens and to study in vitro their sensitivity to some antibacterial drugs most often applied in therapeutic schedules. A total of 104 Staphylococcus strains were isolated. Of them, 66,35 % were Staphylococcus aureus and 33,65 % were coagulase-negative staphylococci (CNS). MRS were 33,65 % of all the strains. Of them, 45,71 % were MRSA and 54,29 % were MRCNS. In the clinical material they were distributed as followed: 62,85 % from nasopharyngeal swabs, 14,28 % from blood cultures, 5,73 % from expectorated sputum, terminal urine and vaginal swabs, and 2,86 % from ear swabs and vascular catheters. MR was due to hyperproduction of normal staphylococcic penicillinase by 27 strains. Six strains contained in their chromosome gene mec A responsible for the synthesis of imperfect penicillin-binding protein. Some 12,5 % of MRSA and 11,8 % of MRCNS were resistant to gentamycin, 15,8 % of MRCNS - to ciprofloxacin, 12,5 % of MRSA and 21,1 % of MRCNS - to rifamycin and 21,1 % of MRCNS - to imipenem. The frequency of MRS strains was within mean values for the country. In-vitro sensitivity could assist the complex treatment of Staphylococcus infections.