Understaffing: a risk factor for infection in the era of downsizing?

Abstract

Francis Bacon observed that "knowledge is power." There must be few uses of power more gratifying than to stop an epidemic of bloodstream infections, as demonstrated in the accompanying article by Fridkin et al.1 Catheter-related bloodstream infections are particularly troublesome because of dramatic morbidity, a case fatality rate of 14%,2 and their iatrogenic nature. Detection of an epidemic of infection depends on the method of surveillance employed, as well as the definitions being used. Fridkin and colleagues make it clear that the rate they would have preferred to calculate was unavailable because of the lack of surveillance data regarding catheter days. For this reason, TPN days was used as a rough surrogate. It should also be noted that the diagnosis of catheterrelated bloodstream infection using definitions employed by the National Nosocomial Infection Surveillance (NNIS) System,3 as done in this study, may not be quite as rigorous as in research publications regarding catheter infections, as previously discussed by Maki.4 The method of collecting blood cultures before and during the outbreak, for example, is not stated, perhaps because NNIS definitions do not make such distinctions. It remains possible that clinicians drew blood cultures more frequently from indwelling catheters during the outbreak, resulting in a higher rate of contamination.6 It also is possible that clinicians became increasingly more disposed to treat when there was a single blood culture positive for a coagulase-negative Staphylococcus. A clinician's decision to treat would result in a diagnosis of bloodstream infection according to NNIS definitions, even if several other sets of simultaneous blood cultures were negative.3 It is not stated whether the method employed for catheter segment cultures was the same as that recommended by Maki,7 and, if so, why a CFU count >15 was not used (as recommended by Maki) rather than qualitative grading of microbial growth. If, however, we accept that the epidemic was due to valid bacteremias and not to overdiagnosis (employing Coleridge's "willing suspension of disbelief'), and that the epidemic extended for almost 2 years, then we must conclude that this was an important outbreak to understand and control. Much knowledge has been gained about the epidemiology and prevention of catheter-related bloodstream infections over the past several decades that could be applied to reduce the rate of infections during an epidemic. Multiple studies have shown that much of the risk for infection of a central venous catheter relates to the manner of insertion of the catheter. Armstrong et al showed that the risk for significant colonization of the catheter (ie, > 15 colonyforming units on semiquantitative culture of a catheter segment) was significantly related to the cumulative experience of the physician inserting the catheter.8 The outbreak described by Fridkin et al occurred in a university-affiliated Veterans Affairs medical center, and, although there is no direct statement regarding the level of experience of those inserting the catheters, the reader would assume that