Virulence Factors Found in Nasal Colonization and Infection of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates and Their Ability to Form a Biofilm

Abstract

Hospitalizations related to Methicillin-resistant Staphylococcus aureus (MRSA) are frequent, increasing mortality and health costs. In this way, this study aimed to compare the genotypic and phenotypic characteristics of MRSA isolates that colonize and infect patients seen at two hospitals in the city of Niterói—Rio de Janeiro, Brazil. A total of 147 samples collected between March 2013 and December 2015 were phenotyped and genotyped to identify the protein A (SPA) gene, the mec staphylococcal chromosomal cassette (SCCmec), mecA, Panton-Valentine Leucocidin (PVL), icaC, icaR, ACME, and hla virulence genes. The strength of biofilm formation has also been exploited. The prevalence of SCCmec type IV (77.1%) was observed in the colonization group; however, in the invasive infection group, SCCmec type II was prevalent (62.9%). The Multilocus Sequence Typing (MLST), ST5/ST30, and ST5/ST239 analyses were the most frequent clones in colonization, and invasive infection isolates, respectively. Among the isolates selected to assess the ability to form a biofilm, 51.06% were classified as strong biofilm builders. Surprisingly, we observed that isolates other than the Brazilian Epidemic Clone (BEC) have appeared in Brazilian hospitals. The virulence profile has changed among these isolates since the ACME type I and II genes were also identified in this collection.

Characteristics of Virulent ST5-SCCmec II Methicillin-Resistant Staphylococcus aureus Prevalent in a Surgery Ward

“…42 Previous reports point out that ST5-SCCmec II is one of the most common types of hospital-associated MRSA isolate, widely prevalent in Asia, Europe, Africa, North and South America. [43][44][45] Furthermore, ST5-SCCmec II-t311 has also been reported as the predominant clone and spread between different hospitals in some areas of China, 46,47 to our knowledge, here is the first report of ST5-SCCmec II-t311 prevalence in Jiangsu Province.…”

Situational analysis on fluoroquinolones use and characterization of high-level ciprofloxacin-resistant Enterococcus faecalis by integrated broiler operations in South Korea

“…Biofilms of bacteria protect them from host immunological responses, phagocytosis, and antimicrobials ( 58 ). The ability to form biofilms is related to the ability of bacteria to adhere to a surface and form a layer, and the density of the layer indicates the strength of the biofilms ( 59 ). In addition, the thicker the layer, the less effective the antimicrobials against bacteria, suggesting a correlation between antimicrobial resistance and biofilm-forming ability ( 60 ).…”

Contribution of Arginine Catabolic Mobile Element and Copper and Mercury Resistance Element in Methicillin-Resistant Staphylococcus aureus: A Vantage Point

“…Spermidine also increases the expression of genes encoding fibronectin-binding proteins (fnbA, fnbB), which have been shown to play a role in biofilm formation by S. aureus [ 17 , 46 ]. A study by Machado et al [ 47 ] showed that S. aureus strains harboring ACME had more ability to form biofilm compared with other strains without ACME [ 47 ]. Regulation of biofilm formation by polyamines such as spermidine has also been observed in Gram-negative bacteria such as Vibrio cholera and Yersinia pestis [ 17 , 48 ].…”