Although the elderly are thought to be at increased risk for acquiring nosocomial infections (NIs), the degree of risk has not been carefully quantified. We determined the decade-specific risks of NIs. The rate was constant at approximately 10 per 1,000 discharged patients from birth to 40 to 49 years. Thereafter the rate rose logarithmically and peaked at greater than 100 per 1,000 discharges after 70 years. Of all NIs, 64% occurred after 60 years of age. Yet, this elderly group made up only 23% of hospitalized patients. In conclusion, while the elderly comprise a small fraction of hospitalized patients, they account for the majority of nosocomial infections.

The intensive care unit at Children's Medical Center in Dallas is a medical-surgical unit that cares for pediatric patients of all ages. In 1978 an outbreak of infections occurred that was caused by a gentamicin-resistant strain of Enterobacter cloacae. Thirty of the 34 patients involved in the outbreak were neonates. Six patients developed bacteremia, five of them neonates. The neonates who became infected were significantly smaller (> 1500 g) and more premature (< 35 weeks) than control patients. Neonates with bacteremia had a significantly higher incidence of congenital anomalies. In a multi-specialty pediatric intensive care unit newborn infants were the group of patients at high risk for nosocomial infection.

An increased incidence in nafcillin (semisynthetic penicillins) resistant Staphylococcus aureus (SR-SA), which peaked in January 1980, was noted in Columbus Children's Hospital (CCH), Columbus, Ohio. To investigate the source of this outbreak, we reviewed the susceptibility patterns of S. aureus strains isolated at CCH for a 12-month period (July 1979 to June 1980). A total of 773 isolates from 706 patients were investigated with a total of 40 patients colonized or infected with SR-SA, approximately 25% of which were diagnosed in the ambulatory clinics. These patients did not have any apparent previous contact with the inpatient unit or inpatient personnel. Eight nosocomial infections were also uncovered. The first appeared in December 1979. Our studies suggested that some SR-SA isolates may have originated in the community and these organisms may not be exclusive to the hospital environment, as was felt to be the case previously. We also determined that the baseline incidence for our hospital of SR-SA was approximately 2% of total S. aureus isolates. Only 35% of the SR-SA demonstrated resistance to multiple antibiotics. This report indicates that community and nosocomial 5. aureus isolates should be monitored for nafcillin resistance. Vancomycin susceptibility should be tested on all isolates and reported for SR-SA in life-threatening infections.

Persons participating in a conference in a major city motel experienced transient mild respiratory illness associated with their presence in the motel conference rooms. The illness was characterized by coughing, sneezing, sore throat, headache, eye irritation, and other symptoms of exposure to a respiratory irritant. Investigation incriminated a chemical shampoo used to clean the conference room rugs approximately one week earlier. Repeated cleaning of the rugs to remove excess cleaning compound eliminated the problem. Excessive application of the shampoo, coupled with a poorly ventilated environment, apparently produced a chemical concentration sufficient to cause clinical illness.

Candida species were once largely regarded merely as causes of aggravating, but rarely life-threatening mucocutaneous infections such as thrush, vulvovaginitis, and intertrigo. Now, however, Candida species have assumed the role of major nosocomial pathogens. This change has paralleled the advent of aggressive cancer chemotherapy, the widespread use of parenteral nutrition, and the practice of advanced surgical techniques including cardiovascular procedures.

Candida is a heterogeneous genus presently grouped with the Fungi Imperfecti (Deuteromycetes). There are over 80 species of Candida; only seven, however, have been recovered from humans: Candida albicans, Candida tropicalis, Candida pseudotropicalis, Candida guilliermondi, Candida krusei, Candida parapsilosis, and Candida stellatoidea. Approximately 90% the systemic Candida infections are due to C. albicans; most of the remaining infections are due to C. tropicalis. Candida species are normal commensals of humans. They are commonly found on the skin, in the gastrointestinal tract, sputum, the female genital tract, and urine from catheterized bladders. C. albicans is found only in human beings and in animal reservoirs. In other sites, such as hospital environments, Candida probably represents contamination by human excreta. Other Candida species may be cultured from soil and other environmental locations. Unlike Aspergillus species, Candida species are uncommon laboratory contaminants.