Antibiotic-resistant Serratia marcescens infection in a hospital.

Over a 12-month period, 74 isolates of Serratia marcescens were obtained from various sources at Tygerberg Hospital. The majority of these isolates were from catheterized patients with urinary tract infections, and were non-pigmented and resistant to all antibiotics tested, excepting amikacin and neomycin. All isolates transferred resistance to tobramycin, gentamicin and tetracycline by conjugation to Escherichia coli recipients as separate markers at low frequency. A non-self-transmissible plasmid conferring resistance to kanamycin, ampicillin and gentamicin was mobilized from Serratia species to E. coli, and became fully self-transmissible in subsequent matings.