Outbreak of Staphylococcus epidermidis nosocomial infections in patients receiving total parenteral nutrition

Pathogenesis of infections related to intravascular catheterization

Over the past few decades, there have been major technological improvements in the manufacture of intravenous solutions and the manufacture and design of catheter materials. However, the risk of infection in patients receiving infusion therapy remains substantial, in part because of host factors (for example, increased use of immunosuppressive therapy, more aggressive surgery and life support, and improved survival at the extremes of life) and in part because of the availability of catheters that can be left in place for very long periods. Microbial components of normal skin flora, particularly coagulase-negative staphylococci, have emerged as the predominant pathogens in catheter-associated infections. Therefore, efforts to prevent skin microorganisms from entering the catheter wound (such as tunnelling of catheters and use of catheter cuffs and local antimicrobial agents) are logical and relatively effective. The specific properties of microorganisms that transform normally harmless commensals such as coagulase-negative staphylococci into formidable pathogens in the presence of a plastic foreign body are being explored. For example, Staphylococcus epidermidis elaborates a polysaccharide adhesin that also functions as a capsule and is a target for opsonic killing. However, the interactions between microorganism and catheter that lead to adherence, persistence, infection, and dissemination appear to be multifactorial.

A cluster of coagulase-negative staphylococcal bacteremias associated with peripheral vascular catheter colonization in a neonatal intensive care unit

BACKGROUND

A cluster of six neonatal cases of coagulase-negative staphylococcal bacteremias occurred in a Los Angeles County neonatal intensive care unit in March 1989.

METHODS

A retrospective cohort study assessed the impact of host-and delivery-related variables, length of hospitalization, duration of antibiotic treatment, performance or duration of invasive procedures, and staffing variables on risk of coagulase-negative staphylococcal bacteremia.

RESULTS

Unstratified analyses yielded eight risk factors with risk ratios greater than 2. After stratification by gestational age (less than 29 weeks) and low birth weight (less than 1500 gm), frequency of blood transfusions, duration of respiratory therapy, heparin lock and central vascular line placement, and hyperalimentation remained associated with elevated risk. Two species were identified, arguing against a common source of infection. Of four cohort months with more than 15 very low birth weight infants in the neonatal intensive care unit, an elevation of coagulase-negative staphylococcus-positive blood cultures and diagnosed bacteremias occurred in only two.

CONCLUSIONS

This cluster of coagulase-negative staphylococcal bacteremia was probably caused by frequent manipulation of catheters in neonates who were at heightened risk because of low birth weight and prematurity.

The role of the nutritional support team in preventing and identifying complications of parenteral and enteral nutrition

As the technology of parenteral and enteral nutrition advances, a multidisciplinary nutritional support team (NST) can be used to assure quality care. NST functions include developing and using standard protocols and solutions, monitoring patients, and preventing complications. Interventions by NSTs can save money for the hospital as well. Examples from Truman Medical Center (Kansas City, Missouri) illustrate how the NST can perform these functions.