Detection of bacteria and fungi in BacT/Alert standard blood-culture bottles

Principles and strategies of antimicrobial stewardship in the neonatal intensive care unit

The judicious use of antibiotics is an important means to limit the emergence of antibiotic-resistant organisms. Although specific guidelines for neonates are often lacking, antibiotic stewardship principles can be applied to the neonatal intensive care unit. Principles include accurately identifying patients who need antibiotic therapy, using local epidemiology to guide the selection of empiric therapy, avoiding agents with overlapping activity, adjusting antibiotics when culture results become available, monitoring for toxicity, and optimizing the dose, route, and duration of therapy. Neonatal intensive care units should develop interdisciplinary antimicrobial stewardship teams with the support of their institutions. Prescriber audit and feedback, as well as preauthorization and formulary restriction of selected antibiotics, are recommended antimicrobial stewardship interventions. Ancillary strategies include education and computerized decision support. Metrics to evaluate antimicrobial stewardship programs should include measurements of patient safety and quality, such as rates of adverse drug events, and appropriate dosing and timing of perioperative prophylaxis.

[Clinical-microbiological management of blood cultures positive for coagulase-negative staphylococci]

A 53-year old male admitted for episodes of sustained ventricular tachycardia subjected to electrical cardioversion, carrier of a right femoral central venous catheter, began with febrile peaks, and Staphylococcus epidermidis was isolated in the blood cultures. What is the value of isolation in the blood cultures of S. epidermidis, a microorganism that forms a part of the usual flora of the skin and mucous of the patient? How should this situation be managed? Should an antimicrobial agent be administered? Which one? For how long?

Clinical characteristics and risk factors for nosocomial candidemia in medical intensive care units: experience in a single hospital in Korea for 6.6 years

The aim of this study was to determine candidemia incidence among patients in a medical intensive-care unit (MICU) and the associated mortality rate and to identify risk factors associated with candidemia. We retrospectively performed a 1:3 matched case-control study of MICU patients with candidemia. Controls were matched for sex, age, and Acute Physiology and Chronic Health Evaluation (APACHE) II score. Candidemia incidence was 9.1 per 1,000 admissions. The most common pathogen was Candida albicans. Crude mortality was 96% among candidemia patients and 52% among controls (P<0.001). Mortality differed significantly between the groups according to Kaplan-Meier survival analysis (P=0.024). Multivariate analysis identified the following independent risk factors for candidemia: central venous catheterization (odds ratio [OR] = 3.2, 95% confidence interval [CI]=1.2-9.0), previous steroid therapy (OR=4.7, 95% CI=1.8-12.1), blood transfusion during the same admission period (OR=6.3, 95% CI=2.4-16.7), and hepatic failure upon MICU admission (OR=6.9, 95% CI=1.7-28.4). In conclusion, we identify an additional independent risk factor for candidemia, the presence of hepatic failure on MICU admission. Therefore, increased awareness of risk factors, including hepatic failure, is necessary for the management of candidemia.

Updated review of blood culture contamination

Blood culture contamination represents an ongoing source of frustration for clinicians and microbiologists alike. Ambiguous culture results often lead to diagnostic uncertainty in clinical management and are associated with increased health care costs due to unnecessary treatment and testing. A variety of strategies have been investigated and employed to decrease contamination rates. In addition, numerous approaches to increase our ability to distinguish between clinically significant bacteremia and contamination have been explored. In recent years, there has been an increase in the application of computer-based tools to support infection control activities as well as provide clinical decision support related to the management of infectious diseases. Finally, new approaches for estimating bacteremia risk which have the potential to decrease unnecessary blood culture utilization have been developed and evaluated. In this review, we provide an overview of blood culture contamination and describe the potential utility of a variety of approaches to improve both detection and prevention. While it is clear that progress is being made, fundamental challenges remain.

Can BacT/Alert FA and FN blood culture bottles increase the recovery of microorganisms in the clinical laboratory?

To evaluate whether the use of BacT/Alert FA and FN blood culture bottles increases the yield of microorganisms, we performed a before-after study. BacT/Alert standard aerobic (AE) and anaerobic (AN) bottles were used from January 1999 to May 2001 (before period). FA and FN bottles were used from May 2001 to March 2003 (after period). A total of 7796 AE, 7807 AN, 4798 FA, and 4787 FN bottles were processed. There were 742 (9.5%) AE-, 598 (7.7%) AN-, 521 (10.7%) FA-, and 396 (8.3%) FN-positive bottles. From these positive bottles 776, 631, 585, and 487 microorganisms were isolated, respectively. Among the isolated microorganisms, 58 (7.5%) and 59 (10.1%) Candida species were isolated from AE and FA bottles, respectively, and 17 (2.7%) and 21 (4.3%) obligate anaerobes were isolated from AN and FN bottles, respectively. We conclude that BacT/Alert FA and FN bottles showed a higher percentage of positivity for microorganisms, in particular for Candida species and obligate anaerobes.

Blood culture examinations at a community hospital without a microbiology laboratory: using an automated blood culture system and performing a Gram stain on positive culture bottles in the institution

To elucidate the existence of microorganisms from blood culture bottles in hospitals without a microbiology laboratory, we changed the system of blood culture examinations. The Oxoid signal blood culture system and submission of all blood cultures to the clinical testing industry was used from July 2002 to December 2002 (first period). Use of the BacT/Alert system and performing of Gram stain for positive culture bottles in our institutions was conducted from January 2003 to June 2003 (latter period). A total of 210 and 193 blood cultures were processed during the first and latter periods, respectively. There were 40 (19.0%) positive cultures in the first period and 32 (16.6%) positive cultures in the latter period. The times from the specimen collection to the Gram stain result that were required were 3.8 and 1.0 days in the first period and the latter period, respectively. The times required for the final report of the blood cultures in the first period and in the latter period were 5.8 and 4.9 days, respectively. We conclude that using a continuous monitoring, automated blood culture system and performing Gram stain for positive culture bottles in institutions without microbiology laboratories may be useful for medical doctors to rapidly determine the existence of microorganisms and to begin adequate antiinfective therapy.