Gram stains of positive blood cultures are the most important factor influencing appropriate therapy. The sooner appropriate therapy is initiated, the better. Therefore, it is reasonable to expect that the sooner Gram stains are performed, the better. To determine the value of timely Gram stains and whether improvement in Gram stain turnaround time (TAT) is feasible, we compared data for matched pairs of patients with cultures processed promptly (<1 hour TAT) with data for patients with cultures not processed promptly (> or =1 hour TAT) and then monitored TAT by control charting.In 99 matched pairs, average difference in time to detection of positive blood cultures within a pair of patients was less than 0.1 hour. For the less than 1 hour TAT group, the average TAT and crude mortality were 0.1 hour and 10.1%, respectively; for the 1 hour or longer TAT group, they were 3.3 hours and 19.2%, respectively (P < .0001 and P = .0389, respectively). After multifaceted efforts, we achieved significant improvement in the TAT for Gram stains.

Because samples are frequently submitted on swabs from distant sites, viability of the organism must be maintained. We compared two transport systems, a new Copan Liquid Stuart's swab with an Easy-Flow swab applicator and the Starplex Liquid Stuart's swab. The purpose of the study was to assess the release and/or recovery of organisms from the Copan system compared to that from Starplex. Triplicate swabs were seeded with 3 dilutions of Neisseria gonorrhoeae, Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae. Although the amount of the initial inoculum was the same for both transport systems, recovery by the roll-plate method at time zero was consistently increased with the Copan system (31 to 87% higher). This is the most important finding in this study. With N. gonorrhoeae, subsequent recoveries were similar for Copan and Starplex but poor for both systems. With N. meningitidis and Haemophilus, higher levels of recovery were clearly obtained with Copan (P < 0.05 to P < 0.001). With Streptococcus, subsequent recoveries for Copan and Starplex were mixed. In conclusion, Copan generally demonstrated better recovery of organisms compared to Starplex even (and especially) at time zero.Proper transport of clinical specimens for culturing infectious agents may be the most important factor affecting the successful evaluation of these specimens. Because many samples on swabs are submitted from sites distant from clinical microbiology laboratories, it is essential that viability of the organism be maintained. While tissues and aspirates remain the specimens of choice, swabs are still commonly submitted to clinical microbiology laboratories for culture. A transport system that will maintain viability of the organism for 24 to 48 h becomes a necessity, as the need to transport these specimens a greater distance becomes a reality. Release of the bacteria from the swab also becomes an important factor. In this study, we compared two transport systems (the Copan Liquid Stuart's swab with an Easy-Flow swab applicator and the Starplex Liquid Stuart's swab) for recovery of fastidious aerobic bacteria. Although both swabs tested use liquid Stuart's as the transport medium, the Copan swab system incorporates a newly designed swab applicator that is said to improve the release of bacteria onto culture plates (5).(This work was presented in part at the 103rd General Meeting of the American Society for Microbiology, Washington, D.C. [C. Drake, J. Barenfanger and G. Lawhorn, Abstr. 103rd Gen. Meet. Am. Soc. Microbiol., abstr. C-045, p. 125, 2003].) MATERIALS AND METHODSThe survival of the following four fastidious aerobic bacteria in the two transport systems at two temperatures was evaluated: Neisseria gonorrhoeae ATCC 43069, Neisseria meningitidis ATCC 13090, Haemophilus influenzae ATCC 10211, and Streptococcus pneumoniae ATCC 6305.The bacterial strains were reconstituted and grown on chocolate agar for 18 h at 37 C°to prepare them for testing. Inocula of the isolates were prepared in 0.85% physiological sa...

No studies have evaluated the efficacy of culturing cerebrospinal fluid (CSF) for fungi. Because of the facts that the most common fungi responsible for meningitis grow well in media utilized for routine bacterial cultures and that cryptococcal antigen tests are commonly ordered, the efficacy of routinely performing fungal cultures specifically to recover fungi has been questioned. We examined data from 1,225 samples of CSF which were cultured for both bacteria and fungi. Twelve specimens yielded fungi, 10 from fungal cultures and 8 from bacterial cultures. Cryptococcus neoformans was found in 10 specimens, Candida albicans was found in 1, and a Cladosporium sp. was found in 1. Eight of 12 positive specimens had concordant culture results. The discordant cases were one specimen that was bacterial culture positive but fungal culture negative and three specimens that were fungal culture positive but bacterial culture negative. Of the latter discrepant cultures, one had fungal contamination only and the other two were positive for cryptococcal antigen. Therefore, omitting the fungal cultures on these specimens would not adversely impact patients. When both cryptococcal antigen tests and bacterial cultures are ordered routinely, eliminating fungal cultures on CSF would have had no impact on the patients in this study. All the clinically significant fungi were detected by the cryptococcal antigen test and/or bacterial culture. With a few exceptions, the combined use of cryptococcal antigen test and bacterial cultures of CSF could replace routine fungal cultures of CSF. Exceptions include settings where fungal pathogens other than Cryptococcus and Candida remain important causes of meningitis.Although studies have addressed the efficacy of performing mycobacterial cultures on cerebrospinal fluid (CSF), no studies have evaluated the efficacy of culturing CSF for fungi (1). Some laboratories may actually use criteria similar to those established for the rejection of mycobacterial cultures to reject cultures on CSF for fungi, but actual data to provide evidence for this process are lacking (5; K. Bromberg, Letter, Lancet i:1023, 1980). Because of the facts that (i) Cryptococcus and Candida spp. (by far the most common fungi responsible for meningitis) grow well in media utilized for routine bacterial cultures and that (ii) cryptococcal antigen tests are commonly ordered, the efficacy of routinely performing fungal cultures specifically to recover fungi on CSF has been questioned. In addition, the onus is now on clinical microbiology laboratories to practice evidence-based medicine, which includes concepts of evaluating tests to ensure that they yield clinically useful results. To determine the clinical utility of routinely performing fungal cultures specifically to recover fungi on CSF, we performed the present study.(This work was presented in part at the 103rd General Meeting at the American Society for Microbiology, Washington, D.C. [G. Lawhorn, J. Barenfanger, and C. A. Drake, Abstr. 103rd Gen. Meet. Am. Soc. Microbi...

We used hospital antibiograms to assess predominant pathogens and their patterns of in vitro antimicrobial resistance in central Illinois, USA. We found a lack of information about national guidelines for in vitro antimicrobial susceptibility testing and differences in interpretation among laboratories in the region.

Rates of contamination of blood cultures obtained when skin was prepared with iodine tincture versus chlorhexidine were compared. For iodine tincture, the contamination rate was 2.7%; for chlorhexidine, it was 3.1%. The 0.41% difference is not statistically significant. Chlorhexidine has comparable effectiveness and is safer, cheaper, and preferred by staff, so it is an alternative to iodine tincture.Contaminated blood cultures cause unnecessary costs and poor patient care and promote the use of unnecessary antibiotics. The current "gold standard" skin preparation is iodine tincture. A new less toxic product ChloraPrep, a one-step application of 2% chlorhexidine gluconate and 70% isopropyl alcohol, is now available. Several studies have established that for preparing the skin for insertion of intravenous lines, chlorhexidine is superior to povidone-iodine or alcohol