INCIDENCE OF ANTIBIOTIC-RESISTANCE IN BLOOD AND URINE ISOLATES FROM HOSPITALIZED-PATIENTS - REPORT FROM A EUROPEAN COLLABORATIVE STUDY

During 1992-93, 2544 isolates from blood cultures, comprising 52% Cram -negative bacilli, 24% Staphylococcus aureus, 15% other staphylococci, 7% Enterococcus faecalis and 2% E. faecium, were consecutively collec ted and identified in 30 laboratories in 21 European countries. In add ition 2512 urine isolates, comprising 82% Gram-negative bacilli? 3% S. aureus, 4% other staphylococci and 11% enterococci mere collected. Th e bacteria were sent to 3 laboratories for susceptibility testing by t he microdilution method in Mueller-Hinton broth. The MICs of penicilli ns and aztreonam for all susceptible Gram-negative bacilli mere 0.25-8 mg/l, penems 0.032-2 mg/l, cefotaxime, ceftazidime and cefpirome or c efepime 0.032-0.25 mg/l, gentamicin, tobramycin and netilmicin 0.125-2 mg/l, amikacin 0.5-4 mg/l, ciprofloxacin 0.016-1 mg/l, trimethoprim 0 .25-1 mg/l and tetracycline 1-2 mg/l, For susceptible staphylococci th e MICs of erythromycin were 0.25-0.5 mg/l, clindamycin 0.125-0.25 mg/l , methicillin 2-8 mg/l, vancomycin and trimethoprim 1-4 mg/l, ciproflo xacin 0.25-1 mg/l, gentamicin and tobramycin 0.25-1 mg/l. For the ente rococci the MICs of ampicillin and vancomycin were 2-4 mg/l and of imi penem, teicoplanin and trimethoprim 0.5-1 mg/l. The antibiotic resista nce rates varied between laboratories, being lower in northern Europe, except for the penems, cefpirome and cefepime, which showed uniformly lower resistance rates. Compared to the earlier European studies the resistance rates to p-lactam antibiotics among the Gram-negatives have not changed except with an increase to cefotaxime and ceftazidime in central Europe. Resistance to aminoglycosides had also increased in ce ntral Europe from 7-8% to 20-21%, but decreased in southern Europe fro m 22-24% to 13-14% among the blood isolates and from 12-28% to 6-7% am ong the urine isolates, There was an increase in resistance to ciprofl oxacin and gentamicin in staphylococci from southern Europe. The preva lence of MRSA was significant in central and southern Europe. It is of importance that collaborative national and international studies on t he incidence of antibiotic resistance are being performed on a repetit ive basis.