Resistance and virulence in community isolates belonging to the Staphylococcus aureus complex: a One Health approach.

• Grant number: 24/10082-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
• Principal Investigator: Ilana Lopes Baratella da Cunha Camargo
• Grantee: Guilherme Henrique Pereira
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Microorganisms known as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) are opportunistic pathogens responsible for causing Healthcare-Associated Infections (HAIs). Among these bacteria, methicillin-resistant S. aureus is considered by the World Health Organization (WHO) as a priority pathogen for the search for new drugs due to its resistance to antibiotics. In addition to antibiotic resistance, virulence factors such as cytolysins (LukSF (PVL), LukED) and superantigens (enterotoxins and TSST-1), plus the ability to form biofilms can aggravate the condition of infections caused by this species. Colonization is a risk factor for infections caused by S. aureus. Colonization by S. aureus of both humans and their pet dogs can pose health risks to each other. In addition, it is also possible that dust circulating in a room frequented by an infected or colonized individual can also pose a risk of dissemination to the health of pets and their owners since dust particles can even contain still-living bacterial cells. For this scientific initiation, in a One Health approach, the objective is to verify the colonization of humans and pet dogs by bacteria of the S. aureus complex, the presence of these in house dust, and the profile of antimicrobial resistance and virulence. The project involves the collection of samples of nasal swabs, feces, and house dust from volunteers without recent use of antibiotics and their dogs, with or without recent use of antibiotics, to isolate bacteria presumptively identified as being of the S. aureus complex. A group of houses without dogs will also be evaluated. The bacteria will be phenotypically identified and tested for antibiotic sensitivity using the automated Phoenix M50 system. Additionally, phenotypic tests will be performed to evaluate the production of hemolytic enzymes and the capacity for biofilm formation. Bacterial DNA will be extracted to detect 24 virulence genes through PCR. This study aims to provide a detailed understanding of the resistance and virulence of S. aureus circulating in the community (human, dog, and house dust) in the São Carlos region, as well as to verify the occurrence of transmission of this species between humans and dogs and the possible involvement of house dust as a reservoir.