Survival of multiply-resistant Klebsiella aerogenes and other gram-negative bacilli on finger-tips.

The survival of various Gram-negative bacilli was evaluated by inoculating the finger-tips of volunteers and determining the number of recoverable organisms in finger washings taken at increasing time intervals up to 60 min. Three epidemic gentamicin-resistant multiply-resistant strains of Klebsiella aerogenes (capsular types K2, K16 and K21) survived better than Pseudomonas aeruginosa, Escherichia coli or non-epidemic antibiotic sensitive klebsiellae of corresponding capsular type. The survival of the epidemic klebsiellae was not altered by curing them of their resistance plasmids. Transfer of their plasmids to E. coli K12 and to sensitive non-epidemic strains of K. aerogenes of corresponding capsular type did not enhance the relatively poor survival of the recipients. We conclude that the enhanced survival on skin of multiply-resistant klebsiellae is not plasmid mediated but may well contribute to the transmissability of these organisms during hospital outbreaks especially when compared with E. coli and Ps. aeruginosa.