Controlled evaluation of supplemented peptone and Bactec blood culture broths for the detection of bacteremia and fungemia

Abstract

Comparisons of conventional blood culture media with newer formulations of Bactec media for radiometric detection are lacking. Therefore, we compared the yield and speed of detection of clinically important microorganisms with supplemented peptone broth (SPB) and Bactec aerobic (6B) and anaerobic (7C or 7D) broths in 7,627 blQod samples from adult patients. Acridine orange stains from SPB, radiometric readings from Bactec, and routine subcultures from all bottles were done at the same time intervals. Bactec grew more facultative gram-positive bacteria (P < 0.02), Bacteroides spp. (P < 0.001), and gram-negative anaerobes (P < 0.001). The two-bottle Bactec system required less time to detect Staphylococcus aureus (P < 0.001), facultative gram-positive bacteria (P < 0.001), Escherichia coli (P < 0.02), facultative gram-negative bacteria (P < .001), and fungi (P < 0.001). Overall, Bactec yielded 11% more microorganisms and detected bacteremia sooner in 18% of samples than did SPB. This advantage was not because of radiometric monitoring, since most positive Bactec bottles were detected macroscopically. SPB offered no advantage for any group of microorganisms. We conclude that Bactec 6B and 7C or 7D broths used as a unit are superior to a single bottle of SPB with an equal volume of blood for the detection of bacteremia and fungemia, and that Bactec's superiority is not due to the method of detection.

Controlled evaluation of the agar-slide and radiometric blood culture systems for the detection of bacteremia and fungemia

“…In this large, multicenter comparative evaluation, the Septi-Chek and BACTEC blood culture systems were equally effective overall in detecting bacteremia. Earlier, we had shown each system to be superior to the conventional broth blood culture system that had been our standard (11,19). Consequently, these findings may be of particular interest to smaller laboratories in institutions that cannot afford the BACTEC instrumentation or to those who may have reservations about the use of the radiometric technology.…”

“…Similarly, there have been favorable evaluations of the BACTEC (2,10,13,16). Our laboratories recently compared each of these systems with a conventional broth system that had been used as our standard (11,19). In these evaluations the RSC and BACTEC each significantly outperformed the conventional system.…”

Detection of pathogenic Campylobacter species in blood culture systems

“…Our present data suggest that if a patient has C. fetus bacteremia, growth can be detected in either the 6B or 7D bottles. Reimer and colleaques (14) have recommended and we currently use in our laboratory a threshold of 31 for aerobic bacteria and 20 for anaerobes. As all campylobacters are considered to be microaerophilic, in both BACTEC systems we monitored the growth indexes until 31 was reached.…”

“…Because the efficiency of blood culture systems for isolating these microaerophilic organisms have not been thoroughly investigated, we studied the ability of the BACTEC radiometric C4C anaerobic and aerobic and the Roche broth-paddle blood culture systems to support their growth. The utility of both the BACTEC and Roche systems for isolating a wide variety of pathogens have been investigated by other workers, but Campylobacter was not mentioned in their studies (14,23,24).…”

Comparison of detection speed and yield in BACTEC NR-860® and Roche BCB® blood culture systems

“…During the last decade, several more or less automated C0,-detecting systems have been introduced. A number of these systems have proved to be superior to many systems that rely on visual examination (2,18,(21)(22)(23)26), including biphasic systems (21,26). The aim of the present study was to compare the Roche BCB@ system and the newly developed automated BACTEC NR-860@ system as regards detection speed and yield.…”