To characterize the epidemiology of invasive pulmonary aspergillosis (IPA).

A retrospective case series.

An 850-bed, academic, tertiary-care medical center.

Adult inpatients, between January 1, 1990, and December 31, 1998, with either a histopathology report consistent with IPA or a discharge diagnosis of aspergillosis.

We reviewed medical records and categorized case-patients as definitive or probable and acquisition of IPA as nosocomial, indeterminate, or community using standard definitions. To determine the rate of aspergillus respiratory colonization, we identified all inpatients who had a respiratory culture positive for Aspergillus species without a histopathology report consistent with IPA or a discharge diagnosis of aspergillosis. Three study intervals were defined: interval 1,1990 to 1992; interval 2,1993 to 1995; and interval 3,1996 to 1998. Carpeting in rooms for patients following heart-lung and liver transplant was removed and ceiling tiles were replaced during interval 1; a major earthquake occurred during interval 2.

72 case-patients and 433 patients with respiratory colonization were identified. Acquisition was nosocomial for 18 (25.0%), indeterminate for 9 (12.5%), and community-acquired for 45 (62.5%) case-patients. Seventeen (23.6%) of the 72 case-patients had prior transplants, including 15 solid organ and 2 bone marrow. The IPA rate per 100 solid organ transplants (SOTs) decreased from 2.45 during interval 1 to 0.93 during interval 2 and to 0.52 during interval 3 (chi-square for trend, 5.44; P<.05). The hospitalwide IPA rate remained stable at 0.03 per 1,000 patient days.

The SOT IPA rate decreased after intervals 1 and 2, although the hospitalwide IPA rate remained stable during the study period. Post-earthquake hospital demolition and construction occurring after interval 2 was not associated with an increase in the rate of IPA at our institution.

The effectiveness of hand-cleansing agents in removing a hospital strain of methicillin-resistant Staphylococcus aureus from artificially contaminated hands of five volunteers was studied.

The products used were plain liquid soap, ethyl alcohol 70% (by weight), 10% povidone-iodine liquid soap (PVP-I), and chlorhexidine gluconate (4%) detergent. The experiments were performed using a Latin square statistical design, with two 5×4 randomized blocks. The removal rates of S aureus cells from contaminated fingertips were estimated by analysis of variance, the response variable being the log10 reduction factor (RF), ie, log10 of the initial counts minus log10 of the final counts. In the first and second blocks, the fingertips of the volunteers were contaminated in mean with 3.76 log10 colony-forming units ([CFU] light-contamination hand) and 6.82 log10 CFU (heavy-contamination hand), respectively.

In the first block, there were significant differences between treatments (P<.05). The 10% PVP-I (RF, 3.76) and 70% ethyl alcohol (RF, 3.51) had significantly higher removal rates than plain liquid soap (RF, 1.96) and 4% chlorhexidine (RF, 1.91). In the second block, 10% PVP-I (RF, 4.39) and 70% ethyl alcohol (RF, 3.27) also were significantly more effective than plain liquid soap (RF, 1.77) and 4% chlorhexidine (RF, 1.37; P<.05). Plain liquid soap was significantly more effective than chlorhexidine (4%) detergent.

The results suggest that 10% PVP-I and 70% ethyl alcohol may be the most effective hand-cleansing agents for removing methicillin-resistant S aureus strain from either lightly or heavily contaminated hands.

To evaluate the contribution of screening to the detection of cases of methicillin-resistant Staphylococcus aureus (MRSA) in a chronic-care facility.

Surveillance and laboratory observational study.

During a 7-month period, we compared imported and acquired MRSA in a chronic-care center by screening patients for carriage of MRSA on admission and discharge, and by recording all cases of clinical specimens positive for MRSA

The study was conducted in a 120-bed chronic-care center. This center admits approximately 850 patients per year. Approximately 90% of the patients were elderly and were admitted from other hospitals.

Of 519 patients admitted during the study period, 129 were positive for MRSA at some point during their residence, including 60 (11.6%) with MRSA found within 48 hours of admission and 69 (13.3%; 53% of all positives) with nosocomial MRSA Of the 519 admissions, 332 (64%) were discharged, of whom 62 (19%) were positive for MRSA. Of these 62, 43 (69%) acquired their MRSA during their stay in the center.

Our study confirms the amplification effect of chronic-care facilities on MRSA propagation. It also shows that screening for MRSA carriage in a chronic-care center facilitates the early identification of a large proportion of patients with MRSA.