医療微生物学と診断

Simple Clinical Information may Guide Treatment of Bloodstream Infections

Abstract

Kemppainen P, Rahkonen M, Luttinen S, Koskela M and Hautala T

Background: Early appropriate antibiotic therapy improves the prognosis of patients with bloodstream infection (BSI). Our goal was to define the use of antimicrobial agents active against Enterococcus species; we explored the possibility that simple clinical and laboratory parameters may be able to identify those individuals at high risk of suffering BSI caused by Enterococcus species.

Methods: Total of 165169 blood culture bottles from 27360 patients were screened. Patients with blood cultures positive for Gram positive cocci in chain were identified (n=365) and they were classified as having hospital acquired infection (HAI) or community acquired infection (CAI) according to the Centers for Disease Control and Prevention (CDC) criteria. We recorded simple clinical and laboratory parameters (plasma C-reactive protein (CRP) concentration, blood white cell count (WBC), data of systolic and diastolic blood pressure, heart rate, and body temperature) at the time when the blood cultures were drawn. Results: It was found that CAI cases were most often (86%) caused by Streptococcus species but the majority (73%) of HAI episodes were caused by Enterococcus isolates (p<0.001). We also found that combining the data of origin of the infection, age of the patient, and plasma CRP concentration could help to predict the bacterial finding within the CAI category: blood cultures positive for enterococci were mostly encountered among the elderly (>60 years) exclusively with low CRP values. In the HAI category, the bacterial finding was not associated with these parameters.

Conclusion: Our study demonstrates that basic clinical observations and laboratory parameters may effectively guide antibiotic treatment early during the course of BSI caused by Gram positive cocci in chain. These parameters are extremely simple to perform and are readily available in most hospitals. We conclude that clinical evaluation should not be overlooked despite the emergence of novel microbiological methods.