A series of handwashing experiments using a pigskin substrate and Serratia marcescens as the contaminant compared the residual activity of a chlorhexidine detergent handwash product alone and incombination with anionic and nonionic-based moisturizing products and surfactant systems. The anionic based moisturizing products and the anionic surfactant system almost completely destroyed the residual antibacterial activity of the chlorhexidine, while the nonionic-based products had minimal effect.

To identify predictors of infection in catheters used for total parenteral nutrition (TPN), clinical and microbiological data were prospectively collected on 169 catheter systems (88 patients). Based on semiquantitative catheter cultures, infection was associated with a positive insertion site skin culture taken close to the time of catheter removal (relative risk [RR] = 4.50), especially one yielding 250 colonies of an organism other than coagulase-negative staphylococci. Infection was also associated with erythema at the insertion site greater than 4 mm in diameter (RR = 2.93). In a subset of 67 catheters for which blood cultures were obtained, infection was also associated with a positive peripheral venous blood culture (RR = 5.90) and a positive central venous blood culture obtained through the catheter (RR = 5.44). Based on a logistic regression model, periodic cultures of the insertion site should be useful in evaluating subsequent fever in stable patients with indwelling central venous catheters. Another source of fever is likely if inflammation is absent and there is either no colonization or there is colonization by less than 50 colonies of coagulase-negative staphylococci at the insertion site. Conversely, the catheter should be removed and cultured semi-quantitatively if the site is colonized by an organism other than coagulase-negative staphylococci. We suggest that blood culture results add little to the risk estimate in these situations.

Hospital-acquired legionella pneumonia is emerging as a major problem; potable water distribution systems have been shown to be the primary reservoirs for the legionella organisms. As a result, disinfection measures have been developed to eradicate the organism from the hospital water supply. Each disinfection modality differs in its design and application such that choosing an appropriate cost-effective control measure requires careful analysis and planning.

We assess in comparative fashion the disinfection modalities of thermal eradication (“heat-and-flush”), instantaneous steam-heating system, chlorination, ultraviolet light irradiation, ozonation and metal ionization. The theoretical bases, the actual procedure or system, the logistics of implementation, the costs and personnel requirements and the advantages and disadvantages are presented for each modality. Criteria for selection of a method, the use of combinations of methods, parameters for installation, pitfalls in implementation and a plan for subsequent environmental surveillance are discussed in detail.

Of the more than 200,000 patients who undergo open heart surgery annually in the United States, 2% to 10% will develop a post-operative infectionrelated to their surgery. The economic impact of such infections on hospitals under the prospective payment system is unclear. To study the effect of such infections on hospital costs and reimbursement patterns, we compared case patients with controls of similar age, sex, urgency of surgery and type of surgery. The postoperative stay for cases was significantly longer than for matched controls (26.8 days and 8.3 days, respectively; p = .0002). The mean hospital cost for case admissions ($25,957) was twice as high as for control admissions ($12,795) (p = .0002). Cases resulted in an average net loss to the hospital of $2,344 per patient, while controls yielded an average net gain of $3,196 per patient (p = .02). We conclude that hospitals have substantial financial incentives tominimize the incidence of postoperative wound infections associated with open heart surgery.

Medical instruments that come in contact with patients' blood and body fluids during invasive procedures should be sterilized after use. Some instruments, however, are too delicate to tolerate auto-clave temperatures, even the lower temperature required by ethylene oxide sterilization. Chemical sterilants are an acceptable alternative but present a different problem because they require prolonged soaking time from six and three-quarters to ten hours. This long exposure to liquids may adversely affect the components of some instruments. Therefore, the manufacturer should always be consulted when prolonged soaking is contemplated.

Another disadvantage to prolonged sterilization cycles is the increased number of instruments that may be required to compensate for the lag in availability. As an acceptable alternative, the Centers for Disease Control (CDC) and others have divided instruments into three categories: instruments that enter normally sterile tissue and the vascular system (these must be sterilized); instruments that contact nonintact skin and mucous membranes (these should receive high-level disinfection); and items that contact only intact skin such as blood pressure cuffs (these require a lower level of disinfection and will not be discussed here). Importantly, it should be noted that the Environmental Protection Agency (EPA), which registers chemical disinfectants/sterilants, does not recognize these categorizations. They register solutions for sterilization or disinfection.

Pseudomonas aeruginosa previously has been reviewed in “Topics in Clinical Microbiology.” However, the increased importance of this micro-organism in nosocomial infections as well as new information on pathogenic mechanisms is such that this topic should be “revisited.” For example, the ubiquitous presence of this bacterium in nature and its ability to survive in hostile environments has been recently emphasized by episodes of P aeruginosa peritonitis, bacteremia and pseudobacteremia that have been linked to contaminated povidone-iodine. Clearly, P aeruginosa is an important pathogen and is deserving of careful and deliberate consideration.

The role of P aeruginosa as a nosocomial pathogen in hospitalized patients with critical illness is rapidly increasing. Recent data from the Centers for Disease Control (CDC) have shown that while nosocomial infections from Escherichia coli and Klebsiella have remained relatively constant from 1975 to 1984, the proportion of such infections caused by Pseudomonas has risen from 6.3% in 1975 to 11.4% in 1984. The frightening aspect of this epidemiologic data is the extremely high rate of mortality associated with hospital-acquired Pseudomonas infections. For example, the mortality rate for Pseudomonas bacteremia often ranges from 67% to 90% for neutropenic cancer patients. Among more general hospital patient populations, the mortality rate for Pseudomonas bacteremia can be similar depending on the underlying condition of the host.