Id color catalase

Fifty-tree SFB strains isolated from contaminated sputum culture on LJ media were used. Around 79% (42/53) of isolate was collected from confirmed TB cases, and 21% (11/ 53) from negative TB cases with coughing more than two weeks. These isolates, collected between February 2016 and May 2017 were stored at −20 °C in liquid media, consisting of skim milk, glycerol, glucose, and tryptone soya broth (STGG). Isolates were piqued onto 5% sheep-blood Columbia agar (Liofilchem^®,roseta d. Abruzzi TE- Italy), and incubated for 24 hours in aerobic conditions at 37 °C. In order to obtain isolated colonies, the obtained colonies were diluted at 10⁻³ with sterile distilled water after a suspension at 0.5 McFarland, and were plated onto 5% sheep-blood Columbia agar for 24 hours in aerobic conditions at 37 °C. Isolated colonies were described, and the bacteria motility was determined after microscope observation of bacteria cells between slide and cover glass. Cells from smear of the colonies were described after Gram and Malachite green staining. Catalase test (ID color Catalase, Biomérieux SA, Lyon, Marcy-l’étoile/France) as well as the oxidase one (Oxydase test Disc, Liofilichem s.r.l Roseto D.A- Italy) were done.

Standard microbiological methods for microorganism's identification were used [18 (link)]. Then, S. aureus identification was based on Gram staining, morphology, catalase positivity (ID color Catalase; bioMérieux, Marcy l'Etoile, France), agglutination in the Pastorex Staph Plus test (Bio-Rad, Marnes la Coquette, France), and free coagulase production with lyophilized rabbit plasma [19 ]. Finally, the isolates were confirmed by API Staph (bioMérieux, Marcy l'Etoile, France).

Samples were collected from the tested surfaces (25 cm²), inside of a tap, drain traps and drain gratings using sterile swabs moistened in a sterile NaCl solution and/or using contact plates (Oxoid, Wesel, Germany). Identification to the level of genus was possible based on microscopic and macroscopic assessment of bacterial colonies as well as biochemical tests: ID Color Catalase (BioMérieux, Marcy-l’Étoile, France)—the reagent detects the presence of catalase, thus enabling the differentiation of bacteria that possess this characteristic, Bactident Oxidase test (MERCK, Darmstadt, Germany)—for the detection of cytochrome oxidase in microorganisms. Identification of the isolated strains to the level of species was carried out using an automatic identification system VITEK^® Compact 2 (BioMérieux, Durham, NC, U.S.). GN cards (BioMérieux, Durham, NC, U.S.) were used for identification of Enterobacterales and a select group of nonfermenting Gram-negative organisms, GP cards (BioMérieux, Durham, NC, U.S.) were applied for the identification of enterococci, streptococci, staphylococci and a selected group of gram-positive organisms. All identified strains were stored for further tests in temperature −80 ± 10 °C, in microbanks (Pro-Lab Diagnostics, Richmond Hill, ON, Canada).