Controlled clinical comparison of Isolator and BACTEC 9240 Aerobic/F resin bottle for detection of bloodstream infections

Abstract

A controlled clinical comparison was carried out with the BACTEC 9240 Aerobic/F resin bottle and the Isolator system with adult patients suspected of having bloodstream infections. A total of 10,500 paired specimens were collected, of which 1,122 from 520 patients were positive. There were 68 false-positive BACTEC bottles; 259 positive cultures that were excluded from analysis because the bottle, the Isolator, or both failed to meet the minimum volume criterion of 8 ml of blood; and 207 positive cultures that were excluded because the isolates were found to be clinically insignificant or of indeterminate clinical significance on the basis of patient assessment. A total of 656 positive cultures from 258 patients formed the basis of the analysis. Significantly more Staphylococcus aureus isolates (P ‫؍‬ 0.03), Staphylococcus epidermidis isolates (P ‫؍‬ 0.03), members of the family Enterobacteriaceae (P ‫؍‬ 0.03), and Pseudomonas aeruginosa isolates (P ‫؍‬ 0.04) were recovered from the resin bottle, and there was no category of organism that was recovered significantly more frequently from the Isolator system. With patients receiving antibiotics at the time of blood culture, S. aureus, S. epidermidis, and gram-negative bacilli were recovered significantly more frequently from the resin bottle. No significant differences between systems were found with cultures from patients not receiving antibiotics at the time of blood culture. Only 12 clinically significant organisms were recovered from the bottle on terminal subcultures, and only 1 of these had not been previously isolated from another blood culture set (10 of the 12) or from the companion Isolator (1 of 12). The Aerobic/F resin bottle continuously monitored in the BACTEC 9240 instrument proved to be superior to the Isolator in overall yield of organisms causing bloodstream infections in adults and required less technician time for specimen processing and examination than the Isolator system.

Clinical comparison of BACTEC 9240 plus aerobic/F resin bottles and the isolator aerobic culture system for detection of bloodstream infections

“…In the current study, we compared two aerobic blood culture systems simultaneously. The results of our study are generally in agreement with those from another study, by Pohlman and colleagues (7), which also compared the performance of the Isolator aerobic culture system to the BACTEC Plus Aerobic/F resin bottle. Like our study, Pohlman and colleagues showed that statistically significantly more isolates of S. aureus and coagulase-negative Staphylococcus spp.…”

Effect of fluconazole prophylaxis on fungal blood cultures: an autopsy‐based study involving 720 patients with haematological malignancy

“…Conventional blood culture seems to be insensitive compared with the newly developed blood tests (Makimura et al , 1994; Obayashi et al , 1995). During the past two decades, there have been a number of changes in blood culture practices and systems (Auckenthaler et al , 1982; Plorde et al , 1985; Murray et al , 1991; Weinstein et al , 1991; Gutierrez et al , 1995; Pohlman et al , 1995a,b; Weinstein, 1996). However, the sensitivity of blood cultures has decreased since 1990.…”

“…During the past two decades, there have been a number of changes in blood culture practices (Auckenthaler et al , 1982; Plorde et al , 1985; Weinstein, 1996). Manufacturers of blood culture systems and media have improved their products (Murray et al , 1991; Weinstein et al , 1991; Pohlman et al , 1995a,b), and there has been a marked trend towards the use of automated systems – most recently, continuous‐monitoring blood culture devices (Gutierrez et al , 1995).…”

Microbiologic Diagnosis of Lung Infection

“…62,63 Although routine blood culture systems have been shown to be highly sensitive for detection of candidemia and cryptococcemia, automated blood culture systems are insensitive for cultivation of monomorphic and dimorphic molds. Isolation of molds (and fastidious bacteria) from blood requires the lysiscentrifugation method (Isolator) [64][65][66] or the use of enriched fungal medium bottles. 67,68 S. pneumoniae can be recovered from urine cultures in as many as 38% of patients with pneumococcal pneumonia.…”