The selective pressure of the widespread use of antimicrobials has resulted in an increasing spread of resistant genes. Thus it would be anticipated and, if fact, has been shown by several studies that organisms from nosocomial infections are
more
resistant to antimicrobial agents than the same species of organisms causing community-acquired infection in a particular geographic area or medical center. However, such data are not available from any medical center in Korea. We, therefore,
examined
the susceptibility data of the nosocomial versus community-acquired pathogens that were isolated in a large university hopital in Seoul. Major pathogenic organisms of 2,015 isolates, 545 nosocomial and 1,470 community acquired pathogens,
recovered
from
clinical specimen in the microbiology laboratory in Asan Medical Center during 6-months period from June to November 1992 were tested for antimicrobial susceptibility by the standard disk diffusion method or automated microdilution minimum
inhibitory
concentration method (Vitek). The nosocomical or community origin of the isolates were determined by the Infection Control Office through the Nosocomial Infection Surveillance Program.
Staphy lococcus aureus and coagulase-negative Staphylococcus isolated from nosocomial infections were significantly less susceptible than those from community-acquired infection to oxacillin, cephalothin, ciprofloxacin, gentamicin, and
erythormycin(p<0.01). Similar findings were obtained for Escherichia coli and Klebsiella pneumoniae to cephalothin, cefotaxime, tobramycin, and gentamicin, and for Pseudomonas aeruginosa to ceftazidime, ofloxacin, piperacillin, and tobramycin.
Enterococcus faecalis isolated from nosocomial infections were significantly more resistant to penicillin and ampicillin (p<0.05). However, Acinetobacter calcoaceticus, Enterobacter cloacae, and Serraiia marcescens did not show a significant
difference
between nosocomial and community acquired isolates. We conclude that the susceptibility patterns of nosocomial and community-acquired pathogens are sufficiently different to warrant separate reports of susceptibility data, which would be useful
to
improve empirical antimicrobial therapy of nosocomial infections.
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