Performance of Sa Select , a Chromogenic Medium for Detection of Staphylococci in Clinical Specimens

Abstract

bIn a preliminary study, known staphylococcus (n ‫؍‬ 86) and other microbial (n ‫؍‬ 12) isolates were plated on three chromogenic media, SaSelect (Bio-Rad, Hercules, CA, USA), CHROMagar Staph. aureus (CHROMagar Microbiology, Paris, France), and S. aureus ID (bioMérieux, Marcy l'Etoile, France). The sensitivities of all the media to detect Staphylococcus aureus after 24 h of incubation were high (100.0%). However, their specificities varied at 93.3% (95% confidence interval [CI], 86.0% to 100.0%) (CHROMagar Staph. aureus), 97.8% (95% CI, 93.5% to 100.0%) (S. aureus ID), and 100.0% (SaSelect). SaSelect also showed the highest sensitivity for recovery and differentiation of other staphylococci. As the best performing chromogenic medium, SaSelect was then prospectively compared to conventional culture and identification tests for the detection of staphylococci from 2,780 clinical specimens. A total of 1,589 staphylococcal isolates were recovered. Of these, 912 were S. aureus and 677 were other staphylococci. The sensitivity and specificity of SaSelect to detect S. aureus in clinical specimens after 24 h of incubation were 99.6% and 99.9% (95% CI, 99.2% to 100.0% and 99.8% to 100.0%), respectively, whereas the sensitivity and specificity using conventional plates combined with laboratory identification methods were 96.8% and 99.5% (95% CI, 95.7 to 97.9% and 99.2% to 99.8%). For the recovery and preliminary identification of other staphylococci, the sensitivity and specificity of SaSelect were 94.4% and 99.9%. SaSelect is a well-performing chromogenic medium that significantly improved the detection of staphylococci, especially S. aureus, compared to conventional culture (P < 0.0001).

The oral cavity revealed as a significant reservoir of Staphylococcus aureus in an acute hospital by extensive patient, healthcare worker and environmental sampling

“…Microbiological methods employed are also variable [6]. For example, in this study we used chromogenic agar for the detection of MSSA and MRSA, which has been shown to have greater sensitivity than conventional culture methods [34].…”

Host-Specific Evolutionary and Transmission Dynamics Shape the Functional Diversification of Staphylococcus epidermidis in Human Skin

“…For the isolation of S. epidermidis, 50-100 mL of the culture were plated onto SaSelect culture plates (Bio-Rad Laboratories) and incubated at 37 C for 24 hours. Small and light pink colonies (Hirvonen et al, 2014) were picked randomly from the plates and verified on the MALDI Biotyper system (Bruker Corporation) according to the manufacturer's instructions. In general, from each skin swab, we aimed at obtaining $10 colonies annotated as ''S.…”

Species and strain cultivation of skin, oral, and gut microbiota

“…Guided by our previous metagenomic data and a literature search 8,11,12,[14][15][16][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] , we compiled the aerobic and anaerobic cultivation conditions reported in Table 1 and Figure 1. To examine the proportion of microbes recovered by these conditions, we first characterized the fungal, bacterial, and viral composition of our samples using shotgun metagenomics as it is culture-independent and yields the most unbiased compositional reconstruction (Figure 2, Table S2).…”