Association Between Contact Sports and Colonization with Staphylococcus aureus in a Prospective Cohort of Collegiate Athletes.

OBJECTIVE: Athletes have a higher risk of infection with Staphylococcus aureus than the general population. Most studies in athletes have included primarily male contact sports participants and have not assessed S. aureus carriage over time. We aimed to examine the epidemiology and risk factors of S. aureus carriage in a cohort of male and female collegiate athletes. STUDY DESIGN: We conducted a prospective cohort study of 377 varsity collegiate athletes from August 2008 to April 2010. A baseline questionnaire ascertained risk factors for colonization. Nasal and oropharyngeal swabs were obtained at enrollment and monthly thereafter to detect S. aureus colonization. The primary outcome was S. aureus colonization, both with methicillin-susceptible and methicillin-resistant S. aureus, as defined by bacterial culture and molecular confirmation. Secondary outcomes were time to colonization with S. aureus and carriage profile, defined as non-carrier, intermittent carrier, or persistent carrier. RESULTS: Overall, 224 contact sports and 153 non-contact sports athletes were enrolled. Contact sports athletes had a higher risk of carrying S. aureus over time: They had higher odds of being colonized with MRSA (OR 2.36; 95 % CI 1.13-4.93) and they tended to carry S. aureus for longer periods of time (intermittent carriage OR 3.60; 95 % CI 2.02-6.40; persistent carriage OR 2.39; 95 % CI 1.21-4.72). Athletes engaged in contact sports also acquired S. aureus more quickly (HR 1.61; 95 % CI 1.02-2.55). CONCLUSIONS: Staphylococcus aureus carriage was common in contact sports athletes. These findings suggest that efforts to prevent transmission of S. aureus among athletes should be focused on contact sports teams.

Longitudinal Assessment of Colonization With Staphylococcus aureus in Healthy Collegiate Athletes.

BACKGROUND: Staphylococcus aureus is the leading cause of skin and soft tissue infections in the United States, and S. aureus colonization increases the risk of infection. Although athletes have a higher risk of infection with S. aureus than the general population, most studies in athletes have not assessed colonization. METHODS: We conducted a prospective cohort study of Vanderbilt University varsity athletes from August 2008 to April 2010. We assessed nasal and oropharyngeal colonization with methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains by obtaining swabs at enrollment and monthly thereafter until the end of the study. The athletes were also monitored for skin and soft tissue infections. RESULTS: We enrolled 377 athletes and trainers (224 in contact sports and 153 in noncontact sports). The total S. aureus colonization prevalence ranged from 34% to 62%, and for MRSA it ranged from 8% to 29%. The colonization rate in the summer was significantly higher than that in the winter (odds ratio for MRSA [ORMRSA], 1.70 [95% confidence interval (CI), 1.23-2.35]; ORMSSA, 1.38 [95% CI, 1.05-1.82]). Of 603 MRSA isolates, 75% carried the staphylococcal cassette chromosome mec (SCCmec) type IV, and 5% carried the genes encoding Panton-Valentine leukocidin. Nine symptomatic S. aureus infections occurred, 7 of which were between July and September. CONCLUSIONS: The S. aureus colonization rate is higher than previously reported and fluctuated over time in this prospective cohort of athletes. The higher colonization prevalence during summer might explain the infectious outbreak during the summer months and may represent a key intervention time for preventing S. aureus disease in athletes.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Costa Rican children.

We collected all Staphylococcus aureus isolates from the National Children's Hospital in Costa Rica to evaluate the prevalence and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA). Of 299 S. aureus isolates, 61% were MRSA. Most MRSA isolates (94.5%) carried SCCmec IV, and 45.6% carried Panton-Valentine leukocidin-encoding genes. The high prevalence of MRSA in this population highlights the need for improvement of antibiotic prescription and infection control measures.

Relationship between maternal and neonatal Staphylococcus aureus colonization.

OBJECTIVE: The study aimed to assess whether maternal colonization with Staphylococcus aureus during pregnancy or at delivery was associated with infant staphylococcal colonization. METHODS: For this prospective cohort study, women were enrolled at 34 to 37 weeks of gestation between 2007 and 2009. Nasal and vaginal swabs for culture were obtained at enrollment; nasal swabs were obtained from women and their infants at delivery and 2- and 4-month postbirth visits. Logistic regression was used to determine whether maternal colonization affected infant colonization. RESULTS: Overall, 476 and 471 mother-infant dyads had complete data for analysis at enrollment and delivery, respectively. Maternal methicillin-resistant S aureus (MRSA) colonization occurred in 10% to 17% of mothers, with the highest prevalence at enrollment. Infant MRSA colonization peaked at 2 months of age, with 20.9% of infants colonized. Maternal staphylococcal colonization at enrollment increased the odds of infant staphylococcal colonization at birth (odds ratio; 95% confidence interval: 4.8; 2.4-9.5), hospital discharge (2.6; 1.3-5.0), at 2 months of life (2.7; 1.6-4.3), and at 4 months of life (2.0; 1.1-3.5). Similar results were observed for maternal staphylococcal colonization at delivery. Fifty maternal-infant dyads had concurrent MRSA colonization: 76% shared isolates of the same pulsed-field type, and 30% shared USA300 isolates. Only 2 infants developed staphylococcal disease. CONCLUSIONS: S aureus colonization (including MRSA) was extremely common in this cohort of maternal-infant pairs. Infants born to mothers with staphylococcal colonization were more likely to be colonized, and early postnatal acquisition appeared to be the primary mechanism.

Molecular distinctions exist between community-associated methicillin-resistant Staphylococcus aureus colonization and disease-associated isolates in children.

OBJECTIVE: To define the molecular epidemiology of colonization and disease-associated isolates of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). DESIGN: Laboratory-based comparative study of clinical staphylococcal isolates. METHODS: We analyzed 255 pediatric CA-MRSA isolates for molecular characteristics associated with colonization and disease. We used polymerase chain reaction to determine the presence of Panton-Valentine Leukocidin and the lantibiotic element, bsaB, and to characterize the staphylococcal cassette chromosome mec type and accessory gene regulator locus. Pulsed-field gel electrophoresis was used to determine genetic relatedness between strains. RESULTS: A total of 150 isolates were obtained from patients with clinical disease (37 invasive infections, 113 noninvasive infections) and 105 from subjects with nasal colonization alone. Of 150 disease-associated isolates, 123 (82%) belonged to pulsed-field gel electrophoresis group USA300, whereas only 19 (18%) of 105 colonization isolates were of the USA300 lineage. Colonization isolates were less likely to possess staphylococcal cassette chromosome mec type IV, Panton-Valentine Leukocidin, or agr type 1 (P < 0.001). CONCLUSIONS: Colonization strains of CA-MRSA in children differ significantly from those strains recovered from patients with staphylococcal infections. This suggests that only colonization with specific strain types, rather than methicillin-resistant Staphylococcus aureus colonization in general, increases the risk for CA-MRSA disease.