A Quantitative Evaluation of Three Blood Culture Systems

Abstract

Three separate blood culture systems were evaluated by parallel culture technic using clinical blood specimens. The three systems under study were a plain brucella broth, the same base medium with polyanethol sulfonate * added in a final concentration of 0.05%, and the same base broth with the polyanethol sulfonate plus sucrose in a final concentration of 30%. After the test media had been inoculated and allowed to incubate for 4 hr., pour plates were prepared from each. The purpose of this step was to determine whether there was a differenc in a blood culture system employing either polyanethol sulfonate or sucrose, or both. The results indicated that specimens from only 74 of 121 patients demonstrated positive culture results in the flask containing only the base broth, whereas 106 were positive when polyanethol sulfonate was added, and 121 were positive when both polyanethol sulfonate and sucrose were incorporated in the base medium. The quantitative results indicated that there were 15 patients from whom recovery of organisms was accomplished only from the polyanethol sulfonate/sucrose medium and an additional 33 patients from whom the total number of organisms recovered from the polyanethol sulfonate/sucrose medium was at least 30% greater than from either the plain broth or the polyanethol sulfonate broth. The results of this study indicate clearly that polyanethol sulfonate has a beneficial effect on the recovery of organisms, possibly by preventing phagocytosis and lessening the inhibitory action of nonspecific antibodies present in the blood specimen. The results also indicate the value of using an osmotic stabilizer such as sucrose to create a better environment for bacterial cells with cell wall damage.