Broth cultures yield vs traditional approach in the workup of infectious keratitis

Abstract

Broth cultures yield vs traditional approach in the workup of infectious keratitisA Kratz, J Levy, I Klemperer and T Lifshitz Abstract Purpose To elucidate whether BACTEC Peds Plus F broth, usually used for culturing body fluids in paediatric departments, can be used for corneal cultures from cases with clinically suspected infectious keratitis, and to compare yields between this method and traditional methods (blood agar, chocolate agar, a fungal media, and swab transport media). Methods All cases with newly diagnosed, nonviral, clinically suspected infectious keratitis with no prior antibiotic therapy, were cultured both in the BACTEC Peds Plus F broth and the traditional method. McNemar's test was used for pairwise comparisons of the rates of positive growth between the two groups. Results In total, 30 eyes were included in this study. The growth rates for the traditional method and the BACTEC broth were similar (50.0 and 53.33%, respectively, P ¼ 1.0). The overall growth rate for the two methods combined was 73.33%, which is 45.29% higher than the reported yield in the literature (average of 50.47%). Conclusions Our results show that BACTEC Peds Plus F broth can be used successfully in the work-up of clinically suspected infectious keratitis. The method has, apparently, several advantages over the 'Traditional method:' time-savings, as only one medium needs to be inoculated, transportation to the laboratory is simpler as there is no need for immediate incubation, and there is no need to keep and maintain a supply of fresh agar media. This method is especially suitable for office settings and remote clinics, but also can be used in hospital setting, as an adjunct, when available, to increase the growth yield.

Do Pathogens from Corneal Scraping Show Their True Colours Better in Bactec Bottles?

“…Unfortunately, as reported in the previous study (Kratz et al 2006), our pathogen recovery from this traditional method is not that encouraging. Thus, we decided to improve culture positive rate for microbial keratitis by adding a new technique using BD BACTEC Peds Plus/F broth (Becton, Dickinson and Company, USA).…”

“…However, even if a specimen of the corneal infiltrate is obtained for microbiological investigation using traditional method, subsequent growth and identification of pathogens occurs only in average of 50.47% cases (Kratz et al 2006). The traditional method involves the use of multiple specimens scraping with direct inoculation onto enriched solid culture agar plates (Kaye et al 2003).…”

“…BD BACTEC Peds Plus/F (Becton, Dickinson and Company, USA) is a type of broth culture medium commonly used in peadiatric practice to isolate microorganisms from small volume sample of about 3 ml blood (Kratz et al 2006). The medium contains 20ml of an enriched soybean-casein digest broth and an optimal amount of sodium polyanethole sulfonate, which enhance the detection of sodium polyanethole sulfonate susceptible organisms.…”

“…The traditional method involves the use of multiple specimens scraping with direct inoculation onto enriched solid culture agar plates (Kaye et al 2003). Studies were conducted to study the suitability of other transport medium and commercially available broth culture medium to increase positive yields (Kratz et al 2006;Kaye et al 2003).…”

“…It has been successfully used to recover not only aerobic and anaerobic bacteria but also fungi. This commercial broth media has been studied in the work-up of microbial keratitis to elucidate whether the BACTEC Peds Plus F could be used for corneal cultures (Kratz et al 2006). Kratz and associates found this method yields 73.33% positive cultures combined with conventional method together.…”