At the Ann Arbor Veterans Administration Medical Center, 30 patients over a 6-month period became nosocomially infected or colonized by methicillin-resistant Staphylococcus aureus. Immediate institution of strict infection control measures, in conjunction with surveillance cultures of personnel and treatment of carriers, did not limit spread of the outbreak strain of MRSA. Multiple nonoutbreak strains, phenotypically exhibiting heteroresistance, were also uncovered. Thirteen hospital personnel were identified as MRSA carriers. Trimethoprim-sulfamethoxazole (TMP-SMX) and rifampin initially eradicated the carrier state, documented by anterior nares cultures in 13 courses of treatment in 11 employees. However, three employees were recolonized, one at one month, one at both one and four months, and one at four months. Treatment of the carrier state reservoir among personnel appeared to have no effect on the emergence and spread of nosocomial MRSA.

A survey of 162 Veterans Administration Medical Center (VAMC) laboratories performing antimicrobial susceptibility testing was performed to determine variation in reported rates of methicillin-resistant Staphylococcus aureus (MRSA) isolation by geographic location and hospital characteristics. Of the 162 VAMC laboratories surveyed, 136 (84%) provided usable data. The percentage of S aureus isolates reported as resistant to methicillin ranged from 0% to 52% with a mean value of 10% among the 136 survey respondents. MRSA were isolated in every VA Medical District and 96% of all respondent laboratories reported isolating at least one MRSA isolate during the preceding year. These data are considered an underestimate of the time MRSA rate in the VA system due to the fact that many laboratories failed to follow key methodologic guidelines for optimal detection of MRSA. A positive correlation was found between MRSA isolation rate and several measures of hospital size and activity including total beds, total admissions, and total antimicrobial susceptibility tests performed. Geographic clustering of MRSA isolation was observed with distinct areas of very high and very low percentages of S aureus isolates reported as MRSA. The data suggest that the geographic distribution of MRSA within the VA system should be monitored closely for evidence of spread from areas with high-MRSA rates to areas of mid- or low-MRSA rates. Evidence of increased MRSA isolation within these areas may necessitate increased caution in patient referral and transfer patterns within the VA system.

Conscientious handwashing is often recommended as an important method for limiting transmission of cytomegalovirus (CMV) from infected individuals to health, education, and child care professionals. To assess the efficacy of handwashing, fingertips of radiation-sterilized latex gloves were inoculated with 0.2 mL of ten different CMV strains. Virus in each inoculum was quantitated by plaque assay. After five minutes, viral inocula were allowed to remain (control), or were washed away by dropwise application of 10 mL of distilled water (DI), 5 mL of 0.08% soap followed by 5 mL of DI, 5 mL of 0.01% Chlorhexidine gluconate followed by 5 mL of DI, or 5 mL of 0.025% povidone-iodine solution followed by 5 mL of DI. Separate glove fingertips were sampled 5, 15, 30, 60, 120 and 240 minutes after washing and cultured in duplicate for CMV. Similar studies were performed using human cadaver skin. Ordinary soap was as effective at preventing CMV recovery as other more expensive agents. For inocula with <5 log10 pfu CMV/mL, washing with water alone was as effective as other agents. This was confirmed in similar studies with human hands using five CMV stains. Handwashing is probably an effective method for removing CMV from contaminated hands.

The initial and cumulative efficacy of two antiseptic handwash preparations in eliminating Serratia marcescens from hands was evaluated on volunteers. Two antiseptics with persistent skin antibacterial activity, 4% chlorhexidine gluconate in detergent and 1.5% triclosan in natural soap, were studied in a new protocol designed according to Food and Drug Administration guidelines. After a single handwash, both preparations exhibited a degerming action statistically superior to the mechanical elimination of the marker organism that was achieved by the nonmedicated controls. Following a further nine hand recontamination sequence with 109 colony-forming units (cfu)/mL S marcescens (mean pre-disinfection baseline, log10 6.6), the efficacy of chlorhexidine and triclosan was significantly augmented: the mean log10 reduction factors were 4.15 and 3.78, respectively. In the absence of internationally accepted testing standards for antiseptic handwash products, the significance of protocol variables is discussed. The advantages to preventative microbiology of antiseptics with persistent skin antibacterial activity are highlighted.

Pseudomonas maltophilia is a free-living ubiquitous organism of wide geographic distribution. It has been isolated from a variety of animals, plants, and from nearly every site on or within the human body, where it is usually a commensal/contaminant. It is frequently cultured as transient flora in hospitalized patients, but occasionally is a cause of opportunistic infections, including bacteremia/septicemia, endocarditis, pneumonia, cholangitis, conjunctivitis, mastoiditis, meningitis, wound infections/abscesses, and urinary tract infections.