Klebsiella and Enterobacter strains derived from hospital infections. I. Correlation between species, phage type and antibiotic sensitivity.

Four hundred and seventy Klebsiella and 103 Enterobacter strains derived from urogenital infections, upper respiratory tract and wound infections were examined. (i) K. aerogenes was the most common among Klebsiella species, K. ozaenae and K. atlantae occurred frequently, K. pneumoniae, K. rhinoscleromatis, K. edwardsii and K. oxytoca were found rarely. The strains isolated from urine showed the most heterogeneous species distribution. Enterobacter species were in the order of frequency E. cloacae, E. liquefaciens, E. aerogenes. (ii) K. aerogenes strains belonged to 10, K. atlantae strains to 6 phage types; phage type II.A1 was the most frequent phage types. Typability varied between 23.7% and 48.0% with the different Klebsiella species, except K. edwardsii and K. oxytoca strains. None of the strains of these species were typable by phages. Among the Enterobacter species examined, only one E. liquefaciens strain was typable by phages. Strains of genus Enterobacter were lysed by the diagnostic phage C14 in 64%, no lysis was observed in the strains of genus Klebsiella. (iii) Multiple resistance was demonstrated in 36.6% of Klebsiella strains and in 16.5% of Enterobacter strains. The majority of the multiresistant strains was isolated from urine in both genera. Multiresistant strains belonged to the species K. aerogenes, E. cloacae and E. liquefaciens. Strains resistant to ampicillin were divided into 6 groups on the basis of cephaloridine and cephalothin resistance. The rate of multiresistant strains was higher among the Klebsiella and Enterobacter strains not typable by phages than in the typable ones.