INTRODUCTION:The purpose of this study was to determine the incidence of the gram negative and gram positive resistance among nosocomial pathogens and to asses the abilities of phenotypic methods to detect different resistance patterns in relation to MIC profiles tested by the sensititer. MATERIAL AND METHODS:This study was performed at Benha University Hospitals. Isolates were collected over a 1- year period,beginning from August 2009 till July 2010.Five hundred clinical specimens were collected from out and inpatients suspected to have bacterial infection.The specimens were collected from[ blood,deep pus,surgical wounds, respiratory tract or urinary tract infection(UTI), and were cultured at 37'C overnight on Blood,MacConkey,Chocolate Media.Gram positive isolates were further subculturd on Mannitol salt agar and Bile aesculin azide agar for identification of S.aureus and Enterococci respectively. For blood cultures, Bactec 9050 bottles were used.The pathogenic nosocomial isolates which were gram negative resistance to 3rd generation cephalosporins(N=54) and gram positive resistant to vancomycin+or - methicillin(N=20) were further subjected to automated identification and minimal inhibitory contraction testing using sensititer.
RESULTS:The resistance rate of nosocomial klebsiellae species were 33.3%for imipenem and 56.6% for meropenem.All tested E.coli strains were susceptible to imipenem and meropenem.The resistance rate of nosocomial Enterobacter species were 14.3% for both imipenem and meropenem.Pseudomonas aeurginosa represents 60% of Pseudomonas species isolates, one strain was pan drug resistant to the whole panel of sensititer antibiotics.• CONCLUSION: Antibiotic resistance represents a major problem in Benha University Hospitals. The Sensititer instrument is a very valuable tool for identification and susceptibility testing of the isolates.D68C AmpC & ESBL Detection Set is an excellent and cheap test to detect different resistant phenotypes. IMP-EDTA combined disc test is a very valuable test to detect MBL production