In order to identify major Inicrobial agems that causing nosocomial infections and also detection of
drug resistancy to current antibiotics, a cross-sectional study was canied out in two ho.\pitals of
medical Sciences University of Hamadan .In this study 620 samples were collected from facilities,
devices and differentparts of intensive care units (ICU) and coronarycare units (CCU) for one year.
The samples were also collected from wards air,wards floor, walls,kitchen sink, sewage,hospital beds,
staffs clothes, gawns, staffs hand.s, suction device, incubator, oxygen mask, ambo bag mask,
thermometer manometer, ventilator, vaso-catheters, stethoscope diaphragm, gavage liquid and
electrodes of ECG. The samples were cultured on E.M.B and Blood agar by sterile wet cotten swabs. A .
smear was also prepared for gram staining. After detection of microbial agents, antibiogram were
performed for strains by agar disk diffusion method. The mean of frequency of contamination was
32.7% in two hospitals. The distribiution (4 gram negative bacteria was 42.3% and gram positive
bacteria was also 57.7%. The rate of contamination in ICU was 31.5% and in CCU was 33.9%
respectively.The most impurtant bacteria were: Micrococci species Staph aureus and epidemidis,
E.coli, Bacillus subtilis, Klebsiella, Enterobacter, Pseudomonas ,diphtheroieds and Entrecocci. The
most drug resistancy were observed in Staphylococci, Micrococci, klebsiella, Enterococci and
Pseudumonas aeroginosa. There was high resistancy to ampicillin, tetracycline, sulfametoxazol and
penicillin.