microbiological evaluation of nosocomial infections by using national nosocomial infection surveillance (nnis) system

background: healthcare-associated infections such as nosocomial infections (ni) are important causes of mortality worldwide. objectives in this study we evaluated the nosocomial infections terms of microbiology (resistance, culturing, etc.) in a referral pediatric hospital based on national nosocomial infection surveillance system. patients and methods in an epidemiological surveillance study during a 14 month-period, patients who had no infection or not been in incubation period at the admission time, but had positive culture after the third day of admission, were defined as a case of nosocomial infection. characteristics and features of each infection were coded and classified. results the total number of hospitalized patients was 7730 and the total number of hospitalized days was 30147 days. the mean age of 103 patients with nosocomial infection was 21.59 ± 3.87 months and the average duration of hospital stay was 25.53 ± 17.63 days. the incidence of ni was 1.33 per 100 hospital discharges and 0.34 per 100 hospital days. the incidence of ni was 1.33 infections per 100 hospital discharges and 0.34 infection per 100 hospital days. the most frequently isolated organisms included coagulase-negative staphylococcus, klebsiella, serratia, yeast, e. coli and pseudomonas respectively. the frequency of antimicrobial resistant isolated organisms was high. half of isolated s. aureus were methicillin resistant. klebsiella was resistant to third generation cephalosporins in 87%, against aminoglicosides in 80%, and against imipenem in 52%. 100% of isolated pseudomonas were resistant to third generation cephalosporins and imipenem. 27 cases (of 103 cases) (26.2%) expired with the diagnosis of ni. conclusions increasing frequency of anti-microbial resistant isolates emphasizes the necessity for bacteriological monitoring of hospitalized children.