We report an outbreak of Enterobacter sakazakii infection and colonization in neonates related to an infant formula contaminated during the manufacturing process. The outbreak occurred in a 2O-bed neonatal intensive care unit during a six-week period in 1988, and involved a total of four infants. Three infants had sepsis and three had bloody diarrhea; all patients responded to intravenous antibiotics and recovered without complications. The E sakazakii isolated from the formula had the same plasmid and multilocus enzyme profile as those isolated from patients. This outbreak demonstrates the significance of commercially contaminated formulas and emphasizes the need to limit contamination and multiplication of bacteria in enteral formulas.

Environmental surface and personnel hand impression cultures were obtained during 13 sampling periods in the University of Virginia Pediatric Intensive Care Unit to document potential reservoirs of nosocomial pathogens. In 78 environmental cultures Staphylococcus aureus was found eight times and gram-negative bacilli ten times. The patient chart cover was the most commonly contaminated surface. Acinetobacter calcoaceticus was found in five of ten cultures positive for gram-negative bacilli. Thirty of 59 hand cultures were positive for S aureus and gram-negative bacilli; nurses and residents had both, respiratory therapists only gram-negative bacilli, and A calcoaceticus was the most commonly isolated bacterium of potentially nosocomial significance (14/30). Laboratory investigation of bacterial survival revealed that gramnegative bacilli survived on a dry formica surface from a few hours up to three days but Acinetobacter survived up to 13 days. Since A calcoaceticus has been implicated in many nosocomial infections, its long survival on a dry surface may be an additional factor in its transmission in hospitals and suggests that more attention be paid to environmental surfaces as a source of significant nosocomial pathogens.

Legionella pneumophila continues to play a role in both community- and nosocomially-acquired pneumonia. We investigated the ability of L pneumophila to adhere to various types of materials such as those found in the hospital air-cooling and potable water distribution systems. Through the use of a unique sampling apparatus, we were able to regularly acquire planktonic and sessile samples and determine the numbers of bacteria present in both populations, in vitro and in situ.

Portions of these apparatuses could be aseptically removed for examination by scanning electron microscopy, or for the determination of the number of viable adherent L pneumophila. The number of bacteria present in each sample was determined by direct plate count, with presumptive L pneumophila colonies being positively identified by direct fluorescent antibody staining techniques.

The results demonstrated that not only are legionellae capable of colonizing various metallic and nonmetallic surfaces but that they are preferentially found on surfaces. Surface-adherent bacteria may play a profound role as a reservoir of these potential pathogens in aquatic environments. Furthermore, these results suggest that any comprehensive legionella monitoring program must include not only water samples but also an examination of the adherent populations.

For several months in 1986, an outbreak of Streptococcus viridans pseudobacteremia occurred at a large teaching hospital. All sources of laboratory blood culture contamination were excluded. A retrospective epidemiological study indicated that one phlebotomist, “P,” collected a disproportionate number of the positive blood cultures. Further comparison of the paired blood culture results from the three months when the incidence was highest revealed a good concordance of results among all other phlebotomists (Kappa = 0.5), while P's results concurred with others less frequently than would be expected even by chance (Kappa < 0.0). Clinical follow-up showed that P did not routinely wear gloves while drawing blood and had eczema of the hands. Skin scrapings from the hands, right index finger/fingernail grew predominantly S viridans species that were compatible with those recovered from contaminated blood cultures. This epidemic demonstrated the need for early detection of this source as a cause of nosocomial pseudobacteremia.

Over several years, I have used microcomputers for most of my statistical analyses. This article is a summary of some of my preferences and thoughts from this experience. Some of the ideas expressed here, of course, are distillations and re-expressions of the thoughts of others.

When you use a microcomputer for your analyses, you assume all the roles traditionally associated with a computer center. You are responsible for the purchase of your machines, supplies and program selection. One problem that may arise is that you may not have a program you need or it may not exist in a version for your computer. If this is the case, you must either find a program that does the job you want or move the data set to a different computer. This problem is less severe now than it was a few years ago because many major statistical packages are available.