title: Phagocytosis and intracellular killing of heterogeneous vancomycin-intermediate Staphylococcus aureus strains.
abstract: Risk factors for invasive infections by heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) may involve resistance to opsonophagocytosis and bacterial killing. hVISA strains typically have a thickened cell wall with altered peptidoglycan cross-linking. To determine whether hVISA may be endowed with an increased resistance to phagocytosis, this study assessed the characteristics of uptake and killing by granulocytes of three hVISA strains. All isolates were analysed by multilocus sequence typing and staphylococcal chromosome cassette mec typing. One of the strains belonged to the Hungarian meticillin-resistant S. aureus (MRSA) clone ST239-MRSA-III and the other two to the New York/Japan MRSA clone ST5-MRSA-II. In the presence of 10 % normal serum, the extent of phagocytosis and killing by blood granulocytes was equivalent for hVISA, MRSA and meticillin-sensitive S. aureus (MSSA) strains. Using granulocytes and serum from one patient who survived hVISA infection, the rate of phagocytosis and killing was also found to be comparable to that by control cells in the presence of 10 % serum. However, phagocytosis and killing of hVISA and MRSA (ATCC 25923) strains by normal granulocytes was markedly decreased in the presence of low concentrations (1 and 2.5 %) of serum from the patient who survived hVISA infection compared with that found with normal human serum. These data suggest that hVISA and MRSA isolates may be more resistant to opsonophagocytosis and bacterial killing than MSSA isolates, at least in some cases.
authors.affiliation: Department of Infectious and Pediatric Immunology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Leonóra
authors.initials: L
authors.lastname: Méhes
authors.affiliation: Department of Infectious and Pediatric Immunology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Szilvia
authors.initials: S
authors.lastname: Taskó
authors.affiliation: Department of Infectious and Pediatric Immunology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Annamária
authors.initials: A
authors.lastname: Székely
authors.affiliation: Department of Bacteriology, National Center for Epidemiology, Budapest, Hungary.
authors.forename: Ákos
authors.initials: Á
authors.lastname: Tóth
authors.affiliation: Department of Phage and Molecular Typing, National Center for Epidemiology, Budapest, Hungary.
authors.forename: Erika
authors.initials: E
authors.lastname: Ungvári
authors.affiliation: Department of Dermatology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Irén
authors.initials: I
authors.lastname: Erdei
authors.affiliation: Department of Medical Microbiology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Dombrádi
authors.affiliation: Department of Medical Microbiology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Judit
authors.initials: J
authors.lastname: Szabó
authors.affiliation: Department of Infectious and Pediatric Immunology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: László
authors.initials: L
authors.lastname: Maródi
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001770:Blood Bactericidal Activity; D002478:Cells, Cultured; D005260:Female; D006098:Granulocytes / Q000276:immunology; D006801:Humans; D008297:Male; D050296:Microbial Viability; D008875:Middle Aged; D058889:Molecular Typing; D010587:Phagocytosis; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000276:immunology*; D014640:Vancomycin / Q000494:pharmacology*; D020713:Vancomycin Resistance; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin