Nasal carriage of
Staphylococcus aureus by
healthcare workers is of great
clinical importance as it facilitates the
contamination of
medical devices and cross-
transmission. However, studies regarding the
epidemiology and dissemination of S. aureus and
Methicillin-resistant S. aureus (
MRSA) within the
Primary Health Care in
Brazil are scarce. The current study aimed to detect and characterize S. aureus and
MRSA strains from the
nasal cavities of 63
healthcare working in
primary health care units in order to determine the
prevalence of S. aureus and
MRSA,
biofilm formation and resistance profile of these isolates.
PCR reactions were performed for detecting mecA, icaA and icaD
genes. The phenotypic antimicrobial susceptibility was assessed by the disk
diffusion method and
biofilm formation by the
Congo Red Agar (CRA)
method. The
MRSA isolates were typed for the Staphylococcal Cassette
Chromosome mec (SCCmec). The
prevalence of nasal carriage of S. aureus was 74.6%, of which 72.3% were
MRSA carrying SCCmec type I (24.4%), III (34.1%), IV (36.6%). Two (4.9%) isolates presented a non-typeable cassette by the performed
technique. The antimicrobial susceptibility evaluation evidenced
penicillin resistance in 66.1% of S. aureus,
erythromycin resistance in 49.2%, while 37.3% were resistant to
oxacillin, 28.8% to
cefoxitin, 5.1% to
levofloxacin and 5.1% to
clindamycin. All isolates were
biofilm producers and 96.6% of the
strains contained the ica
biofilm-forming
genes (icaA and/or icaD). We have demonstrated a high
prevalence of S. aureus and
MRSA carriage among
health care working in
Primary Health Care units, the presence of SCCmec types I, III and IV, in addition to their high
ability to form
biofilm, factors that possibly contribute to the dissemination and persistence of these pathogens within the
primary care services. These observations highlight the importance of broadening the perspective of
Health Care-Associated
Infections prevention, including all
health care levels, which are currently little explored. In addition, the dynamics and resistance mechanisms of S. aureus
transmission still need to be further clarified to enable the implementation of more effective prevention
measures.