Complex Clonal Diversity ofStaphylococcus aureusNasal Colonization among Community Personnel, Healthcare Workers, and Clinical Students in the Eastern Province, Saudi Arabia

Abstract

Here, 210 healthy participants including community personnel (70), clinical students (68), and healthcare workers (HCWs) (72) from the eastern region of Saudi Arabia were studied. Sixty-three Staphylococcus aureus isolates were obtained from the nares of 37% of the community personnel and 26% of the clinical students and HCWs. Methicillin-resistant S. aureus (MRSA) was found in 16% (10 isolates) of the 63 isolates; six were from HCWs. Molecular characterization revealed high clonal diversity among the isolates, with 19 different spa types, 12 clonal complexes (CCs), and seven sequence types (STs) detected. The most common strain type was USA900, CC15, and t084, seen in 11 methicillin-susceptible S. aureus (MSSA) isolates. Moreover, three novel spa types in six isolates and one novel ST in two isolates were identified, most from HCWs. Interestingly, 29 isolates were mecA positive by PCR, whereas only 10 isolates were MRSA by disk diffusion (cefoxitin resistant). Of the 19 MSSA mecA-positive isolates, 16 were PBP2a negative, leaving three unique isolates from HCWs that were mecA and PBP2a positive yet cefoxitin susceptible. Our findings highlight the importance of phenotypically and genotypically characterizing S. aureus strains isolated from healthy communities to monitor the risk of possible cross-transmission to hospitalized patients. The identified strains showed a clonal lineage relationship with previously reported S. aureus and MRSA strains acquired from hospital settings.

Nasal Carriage by Staphylococcus aureus among Healthcare Workers and Students Attending a University Hospital in Southern Brazil: Prevalence, Phenotypic, and Molecular Characteristics

“…Similar to our results, high resistance rates to beta-lactams antimicrobials, such as ampicillin and penicillin, have been reported to S. aureus isolated from nasally colonized individuals from both cohorts [17,18,20,36,40,41]. However, the rates of clindamycin/erythromycin resistance may vary according to the geographical region.…”

“…None of the variables analyzed (gender, age, and working hours per day or year) were associated with S. aureus colonization. Finally, El-Mahdy et al [18] reported a prevalence of 26.0% of S. aureus nasal carriers among both healthcare workers and clinical students in Saudi Arabia. ese authors did not evaluate the risk factors associated with colonization.…”

“…After birth, hands are the main vector for transmitting S. aureus from the surfaces to the nose [11,12]. Particularly in hospitals, healthcare workers and patients who are nasal carriers may be the source for the transmission and spread of S. aureus in these settings [13][14][15][16][17][18]. Similarly, students who have continuous hospital exposure during their internship may represent an important source for transmitting S. aureus within the hospital environments [14,19].…”

“…Crucially, high rates of colonization by methicillin-resistant S. aureus (MRSA) have been reported among healthcare workers [16,17], and increasing rates of MRSA colonization among students with continuous hospital exposure have also been reported [19]. Besides their role in S. aureus transmission in hospital settings, healthcare workers and students may also serve as the vector for cross-transmission of MRSA between the community and hospital populations [14,18].…”

Phenotype-Genotype Characterization and Antibiotic-Resistance Correlations Among Colonizing and Infectious Methicillin-Resistant Staphylococcus aureus Recovered from Intensive Care Units

“…This is a logical finding, as nares is the main ecological niche of colonizing isolates. 30 Antibiogram analysis revealed that both colonizing and infectious isolates exhibited almost equal resistance to amikacin, amoxicillin-clavulanic acid and clindamycin. These results were expected as those antibiotics belonged to classes to which MRSA strains were resistant.…”