Teicoplanin

Antimicrobial susceptibility was tested using the disc diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute [13 ]. We determined the susceptibility to clindamycin, erythromycin, fusidic acid, linezolid, oxacillin, penicillin, rifampicin, teicoplanin, tetracycline, trimethoprim-sulfamethoxazole, and vancomycin (BBL, BD, USA). Isolates were considered to be susceptible isolates when their zones of inhibition conformed to the intermediate susceptibility category for a given antibiotic.

Antimicrobial susceptibility of the SAR Bari strain was determined by a BD PHOENIX^™ 100 instrument (Becton Dickinson, Franklyn Lake, NJ). Data were elaborated by the BD Epicenter Expert System according to EUCAST rules (http://www.eucast.org). The PMIC/ID-88 (BD) panel was used to test susceptibility to ampicillin, cefoxitin, ceftaroline, ciprofloxacin, clindamycin, daptomycin, erythro-mycin, fosfomycin, fusidic acid, gentamicin, imipenem, linezolid, moxifloxacin, mupirocin, nitro-furantoin, oxacillin, penicillin, rifampin, teicoplanin, tetracyclin, tigecycline, trimethoprim/ sulfamethoxazole, and vancomycin. The Epsilometer Test (ETest) was used for testing resistance to ciprofloxacin, daptomycin, erythromycin, gentamicin, moxifloxacin, tetracyclin, tigecycline, trimethoprim/sulfamethoxazole, and vancomycin (bioMérieux, Marcy-L’Étolie, France and Liofilchem, Roseto degli Abruzzi, Italy). All tests were repeated on four independent technical replicates. MIC interpretative breakpoints were defined according to EUCAST recommendations. Staphylococcus aureus ATCC 29213 was used as a control strain.

Susceptibility testing was carried out by disc diffusion technique following the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines (www.eucast.org) using 1U penicillin, 30 µg tetracycline, 30 µg cefoxitin, 2 µg clindamycin, 15 µg erythromycin, 10 µg norfloxacin, 10 µg gentamicin, 10 µg linezolid, 5 µg rifampicin, 1. 25 µg +23.75 µg trimethoprim-sulfamethoxazole, and 10 µg fusidic acid (Rosco NeoSenstabs, Taastrup, Denmark). Inducible clindamycin resistance was detected by placing clindamycin and erythromycin 12–20 mm apart (D-test). Brain Heart Infusion agar supplemented with teicoplanin (5 mg/L) (Becton Dickinson, Denmark) was used to screen MRSA isolates for glycopeptides resistance by a spot test; if 10 or more colonies were detected on these plates, E-tests (bioMérieux, Marcy I’Etoile, France) were used to determine the minimum inhibitory concentration of vancomycin and teicoplanin [11] (link). Multidrug resistance (MDR) was defined as resistance to at least three distinct antimicrobial classes or being MRSA [12] .