pathogens Article First Case of Staphylococci Carrying Linezolid Resistance Genes from Laryngological Infections in Poland Michał Michalik 1, Maja Kosecka-Strojek 2,* , Mariola Wolska 2, Alfred Samet 1, Adrianna Podbielska-Kubera 1 and Jacek Mi˛edzobrodzki 2 1 MML Medical Centre, Bagno 2, 00-112 Warsaw, Poland;
[email protected] (M.M.);
[email protected] (A.S.);
[email protected] (A.P.-K.) 2 Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland;
[email protected] (M.W.);
[email protected] (J.M.) * Correspondence:
[email protected] Abstract: Linezolid is currently used to treat infections caused by multidrug-resistant Gram-positive cocci. Both linezolid-resistant S. aureus (LRSA) and coagulase-negative staphylococci (CoNS) strains have been collected worldwide. Two isolates carrying linezolid resistance genes were recovered from laryngological patients and characterized by determining their antimicrobial resistance patterns and using molecular methods such as spa typing, MLST, SCCmec typing, detection of virulence genes and ica operon expression, and analysis of antimicrobial resistance determinants. Both isolates were multidrug resistant, including resistance to methicillin. The S. aureus strain was identified as ST- 398/t4474/SCCmec IVe, harboring adhesin, hemolysin genes, and the ica operon. The S. haemolyticus strain was identified as ST-42/mecA-positive and harbored hemolysin genes. Linezolid resistance Citation: Michalik, M.; S. aureus Kosecka-Strojek, M.; Wolska, M.; in strain was associated with the mutations in the ribosomal proteins L3 and L4, and in Samet, A.; Podbielska-Kubera, A.; S.