The emergence of gentamicin-resistant klebsiellae in a large general hospital.

Between March and December, 1975, an outbreak of infection with gentamicin-resistant Klebsiella pneumoniae (klebsiella (Gmr)) occurred at the Royal Melbourne Hospital. The klebsiellae were considered to be causing significant infection in 24 of 42 patients harbouring the microorganism. Commonest culture sources were urine and sputum, all but one of the significant urinary infections being associated with indwelling bladder catheters. Antibiotic therapy had been given to 40 patients before the isolation of klebsiella (Gmr), and of these 22 had received gentamicin. Cross infection was a major factor in the outbreak, and control measures (to limit this aspect and curtail the usage of gentamicin) have prevented wider spread within the hospital; at the time of writing the microorganism had been eradicated from all but one of the infected patients. It was shown that klebsiella (Gmr) carry an R-factor capable of transferring gentamicin resistance. Of 22 isolates tested quantitatively, 20 were resistant to 10 mug/ml of gentamicin.