A methicillin- and rifampin-resistant strain of Staphylococcus aureus was introduced into a university hospital by interstate transfer of an infected surgical patient. An outbreak occurred, and 17 patients became infected or colonized with the epidemic strain. Reservoirs appeared to be patients who were infected or colonized with the resistant S aureus and possibly two nurses who were nasal carriers. The outbreak isolate was likely spread by contact with contaminated hands of personnel. A retrospective case-control study identified tracheostomy, debridement, and irrigation of wounds by power spray and prolonged nasogastric intubation as risk factors for acquisition of the epidemic strain. Analysis of factors by groups indicated that surgical procedures, wound care procedures and instrumentation of the respiratory tract were significantly associated with cases. The nasal carrier state was eradicated in two nurses by topical application of 5% vancomycin. The epidemic strain was eradicated from the hospital 8 months after it was introduced.

Sequential outbreaks of infection due to gentamicin-resistant Klebsiella pneumoniae (GRKP) types 30 and 19 occurred in the neonatal intensive care unit (NICU) at the Medical College of Virginia in 1977 and 1978. The extensive epidemiologic investigation carried out included a case-control study, careful review of aseptic technique, and cultures from nursery staff and environment. The gastrointestinal (GI) tracts of the patients were the reservoirs for GRKP, and the epidemic strain was transmitted by hands of personnel. The case-control study showed a significant relationship between acquisition of GRKP by patients and oropharyngeal and GI instrumentation, including use of bag resuscitation, oropharyngeal suctioning, and use of nasogastric feeding tubes. The findings of the case-control study were supported by observation of the patient care techniques practiced by NICU staff. Institution of control measures based on results of the epidemiologic investigation of the first outbreak rapidly brought the second outbreak under control, even though cohorting or use of routine isolation was not possible. Whereas GI colonization and hand transmission have been described previously in outbreaks of K. pneumoniae infections in NICUs, this study is the first to document the mode of inoculation of patients' GI tracts by contaminated hands of personnel.