Multiclonal outbreak of methicillin-resistant Staphylococcus aureus infections on a collegiate football team

Outbreak of community-acquired Staphylococcus aureus skin infections in an Australian professional football team

OBJECTIVES

Skin and soft tissue infections commonly affect athletes and can lead to cluster outbreaks if not managed appropriately. We report the findings of an investigation into an outbreak of community-acquired Staphylococcus aureus infection in an Australian professional football team.

DESIGN

Retrospective cross-sectional study.

METHODS

Nose, axilla, groin and throat swab were collected from 47 participants. MRSA and MSSA isolates underwent antibiotic susceptibility testing, binary typing and whole genome sequencing. Infection control practitioners (ICPs) investigated the training grounds for risk factors in the transmission of S. aureus.

RESULTS

Almost half of the participants (n=23, 48.9%) were found to be colonised with MSSA. An outbreak cluster of MRSA ST5 closely related to the fusidic acid-resistant New Zealand NZAK3 clone was identified in a group of four players. MSSA ST15 and MSSA ST291 strains were found to have colonised and spread between two and five players, respectively. All participants were advised to undergo decolonisation treatment consisting of 4% chlorhexidine body wash and mupirocin nasal ointment for ten days. The ICP team identified several unhygienic practices within the club's shared facilities that may have played a role in the transmission of S. aureus.

CONCLUSIONS

We report for the first time a community-associated S. aureus outbreak involving the highly successful fusidic acid-resistant MRSA ST5 clone in a professional football club associated with inadequate hygiene procedures. Management and prevention of S. aureus relies heavily on hygiene education and adherence to personal and environmental hygiene practices and policies.

Community-associated Methicillin-Resistant Staphylococcus aureus Infection Rates and Management among Student-Athletes

PURPOSE

Although community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections have reduced among inpatient populations, the incidence in athletics continues to range greatly dependent on the sport. Over the 2015 to 2016 and 2016 to 2017 school years, we assessed the annual CA-MRSA incidence, sport risk, referral practices, and management protocols or interventions among high school and intercollegiate athletics.

METHODS

This study targeted high school and intercollegiate athletic programs across the United States. For the 2015 to 2016 study, 269 athletic trainers completed a one-time questionnaire. In the 2016 to 2017 study, 217 athletic trainers reported data bimonthly during the academic year. Each questionnaire targeted demographic information, physician-confirmed CA-MRSA infection occurrence, and management of CA-MRSA infections and bacterial skin lesions.

RESULTS

The CA-MRSA infection incidence was 26.8 per 10,000 athletes (95% confidence interval [CI], 24-30) in 2015-2016 and 20.3 per 10,000 athletes (95% CI, 18-23) in 2016-2017. The CA-MRSA infection incidence was high in wrestling and football compared to the general student-athlete population. During the 2015 to 2016 study, the wrestling incidence rate was 248.3 per 10,000 (95% CI, 204-302); the football incidence rate was 71.0 per 10,000 (95% CI, 60-85). In the 2016 to 2017 study, the wrestling incidence rate was 100.0 per 10,000 (95% CI, 66-151); the football incidence rate was 81.8 per 10,000 (95% CI, 68-99). At least 23% of respondents denoted at least one physician-confirmed CA-MRSA infection within their populations (2015-2016, 39%, n = 105; 2016-2017, 23.5%, n = 51). In the 2015 to 2016 survey, respondents indicated that athlete education and environmental decontamination were the most used management steps (51.8%, n = 582).

CONCLUSIONS

Despite increased awareness of CA-MRSA, more educational efforts focusing on best practices and education are needed, especially with athletes and the medical community involved in their care.

Infection Control Practices and Methicillin-Resistant Staphylococcus aureus Skin Infections: A Survey of Students in US Chiropractic Programs

OBJECTIVE

The purpose of this study was to assess the incidence of self-reported history of physician-diagnosed methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infection (SSTI) among chiropractic students and any association with infection control behaviors (hand and table hygiene, sharing gowns, and sharing lotion) and initiation of patient care.

METHODS

Questionnaires were obtained from 312 students attending half (9/18) of US chiropractic campuses. The questionnaire was derived from earlier studies led by Bearman in 2010 and Evans in 2007. Associations were assessed with Fisher exact test. Crude odds ratios were calculated for each of the variables. Two logistic regression models were produced.

RESULTS

Attendance at 1 campus was associated with postmatriculation MRSA SSTI in univariate analysis (P = .010). The logistic regression model was significant (P < .05), but the composing variables were not.

CONCLUSIONS

Fewer than 5 cases of MRSA SSTI were detected overall, revealing a low rate of reported postmatriculation MRSA SSTI among these students. There was a univariate association with postmatriculation MRSA SSTI at 1 chiropractic college.

Infectious Diseases Associated With Organized Sports and Outbreak Control

Participation in organized sports has a variety of health benefits but also has the potential to expose the athlete to a variety of infectious diseases, some of which may produce outbreaks. Major risk factors for infection include skin-to-skin contact with athletes who have active skin infections, environmental exposures and physical trauma, and sharing of equipment and contact with contaminated fomites. Close contact that is intrinsic to team sports and psychosocial factors associated with adolescence are additional risks. Minimizing risk requires leadership by the organized sports community (including the athlete's primary care provider) and depends on outlining key hygiene behaviors, recognition, diagnosis, and treatment of common sports-related infections, and the implementation of preventive interventions.

CA-MRSA Infection Incidence and Care in High School and Intercollegiate Athletics

PURPOSE

Position papers offer solutions to manage community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), yet few studies establish the infection rate, management protocols, and referral practices among student-athletes. Over the 2012-2013 and 2013-2014 school years, we assessed the annual CA-MRSA infection incidence, sport risk, referral practices, and management steps among high school and intercollegiate athletics.

METHODS

This study targeted high school and intercollegiate athletic programs in the Northeastern United States. For the 2012-2013 study, 156 athletic trainers completed a one-time questionnaire. In the 2013-2014 study, 87 athletic trainers reported data bimonthly during the academic year. Each questionnaire targeted demographic information, physician-confirmed CA-MRSA infection occurrence, and management of CA-MRSA infections and bacterial skin lesions.

RESULTS

The CA-MRSA infection incidence was 15.5 per 10,000 athletes (95% confidence interval [CI], 13-19) in 2012-2013 and 16.3 per 10,000 athletes (95% CI, 13-21) in 2013-2014. The CA-MRSA infection incidence was higher in wrestling and football compared to the general student-athlete population. During the 2012-2013 study, the wrestling incidence rate was 90.2 per 10,000 (95% CI, 62-132); the football incidence rate was 42.3 per 10,000 (95% CI, 31-59). In the 2013-2014 study, the wrestling incidence rate was 89.0 per 10,000 (95% CI, 50-158); the football incidence rate was 61.4 per 10,000 (95% CI, 42-90). In both studies, primary care and general physicians received over 60% (2012-2013: 60.5%, n = 133; 2013-2014: 66.5%, n = 125) of referrals. In the 2012-2013 study, respondents indicated that student-athlete isolation and setting decontamination were common management steps used (58.1%, n = 306).

CONCLUSIONS

The incidence of CA-MRSA infections among student-athletes remains high. Therefore, it is critical that sports medicine providers continually reassess management protocols and best practices.

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.

The use of the temporal scan statistic to detect methicillin-resistant Staphylococcus aureus clusters in a community hospital

Background

In healthcare facilities, conventional surveillance techniques using rule-based guidelines may result in under- or over-reporting of methicillin-resistant Staphylococcus aureus (MRSA) outbreaks, as these guidelines are generally unvalidated. The objectives of this study were to investigate the utility of the temporal scan statistic for detecting MRSA clusters, validate clusters using molecular techniques and hospital records, and determine significant differences in the rate of MRSA cases using regression models.

Methods

Patients admitted to a community hospital between August 2006 and February 2011, and identified with MRSA > 48 hours following hospital admission, were included in this study. Between March 2010 and February 2011, MRSA specimens were obtained for spa typing. MRSA clusters were investigated using a retrospective temporal scan statistic. Tests were conducted on a monthly scale and significant clusters were compared to MRSA outbreaks identified by hospital personnel. Associations between the rate of MRSA cases and the variables year, month, and season were investigated using a negative binomial regression model.

Results

During the study period, 735 MRSA cases were identified and 167 MRSA isolates were spa typed. Nine different spa types were identified with spa type 2/t002 (88.6%) the most prevalent. The temporal scan statistic identified significant MRSA clusters at the hospital (n = 2), service (n = 16), and ward (n = 10) levels (P ≤ 0.05). Seven clusters were concordant with nine MRSA outbreaks identified by hospital staff. For the remaining clusters, seven events may have been equivalent to true outbreaks and six clusters demonstrated possible transmission events. The regression analysis indicated years 2009–2011, compared to 2006, and months March and April, compared to January, were associated with an increase in the rate of MRSA cases (P ≤ 0.05).

Conclusions

The application of the temporal scan statistic identified several MRSA clusters that were not detected by hospital personnel. The identification of specific years and months with increased MRSA rates may be attributable to several hospital level factors including the presence of other pathogens. Within hospitals, the incorporation of the temporal scan statistic to standard surveillance techniques is a valuable tool for healthcare workers to evaluate surveillance strategies and aid in the identification of MRSA clusters.

Infectious disease outbreaks in competitive sports, 2005-2010

CONTEXT

Old, evolving, and new infectious agents continually threaten the participation of competitors in sports.

OBJECTIVE

To provide an update of the medical literature on infectious disease outbreaks in sport for the last 5 years (May 2005-November 2010).

MAIN OUTCOME MEASURE(S)

A total of 21 outbreaks or clusters were identified.

RESULTS

Methicillin-resistant Staphylococcus aureus (n = 7, 33%; mainly community acquired) and tinea (trichophytosis: n = 6, 29%) were the most common pathogens responsible for outbreaks. Skin and soft tissue was the most common site of infection (n = 15, 71%).

CONCLUSIONS

The majority of outbreaks reported occurred in close-contact sports, mainly combat sports (ie, wrestling, judo) and American football. Twelve outbreaks (57%) involved high school or collegiate competitors. Common community outbreak pathogens, such as influenza virus and norovirus, have received little attention.

Evaluation of persistent antimicrobial effects of an antimicrobial formulation

CONTEXT

Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is becoming more prevalent in healthy athletic populations. Various preventive measures have been proposed, but few researchers have evaluated the protective effects of a prophylactic application of a commercially available product.

OBJECTIVE

To compare the persistent antimicrobial properties of a commercially available antimicrobial product containing 4% chlorhexidine gluconate (Hibiclens) with those of a mild, nonmedicated soap (Dr. Bronner's Magic Soap).

DESIGN

Cross-sectional study.

SETTING

Microbiology laboratory, contract research organization.

PATIENTS OR OTHER PARTICIPANTS

Twenty healthy human volunteers.

INTERVENTION(S)

The test and control products were randomly assigned and applied to both forearms of each participant. Each forearm was washed for 2 minutes with the test or control product, rinsed, and dried. At, 1, 2, and 4 hours after application, each forearm was exposed to MRSA for approximately 30 minutes.

MAIN OUTCOME MEASURE(S)

Differences in numbers of MRSA recovered from each forearm, test and control, at each post-application time point were compared.

RESULTS

Fewer MRSA (P < .0001) were recovered from the forearms treated with the test product (4% chlorhexidine gluconate) than from the forearms treated with the control product (nonmedicated soap).

CONCLUSIONS

The 4% chlorhexidine gluconate product demonstrated persistent bactericidal activity versus MRSA for up to 4 hours after application.

Practices and procedures to prevent the transmission of skin and soft tissue infections in high school athletes

Skin and soft tissue infections (SSTIs) are frequent in student athletes and are often caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). We evaluated the awareness of CA-MRSA among high school coaches and athletic directors in Missouri (n = 4,408) and evaluated hygiene practices affecting SSTI transmission. Of 1,642 (37%) respondents, 61% received MRSA educational information during the past year and 32% indicated their school had written guidelines for managing SSTIs in athletes. Coaches and athletic directors aware of written guidelines reported a lower incidence of SSTIs in student athletes (26%) compared to those without written policies (34%, p = .03). When confronted with SSTIs, 49% of respondents referred student athletes to the school nurse or a physician. A relationship exists between school policies for SSTI management and lower incidence of SSTIs. Educational initiatives by school nurses in conjunction with athletic staff may lead to practices that limit SSTIs in this at-risk population.

Community-based intervention to manage an outbreak of MRSA skin infections in a county jail

This article describes a community-based intervention to manage an outbreak of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin infections in a midwestern county jail. A systematic investigation conducted by a family medicine residency program identified 64 total cases and 19 MRSA cases between January 1 and December 31, 2007. Factors contributing to MRSA transmission included inadequate surveillance, lack of antibacterial soap, and a defective laundry process. All 19 isolates were CA-MRSA and all seven tested by pulsed-field gel electrophoresis (PFGE) were USA300. Four of the seven isolates showed variation of their PFGE patterns. A primary care approach using community-based resources effectively reduced the number of cases in this heterogeneous outbreak of CA-MRSA, with the last MRSA being isolated in October 2007.

Community-acquired methicillin-resistant Staphylococcus aureus in surgically treated hand infections

PURPOSE

An increase in the incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections has been observed. The purpose of this study is to determine the change in proportion of surgically treated CA-MRSA hand infections over the last decade and to identify associated risk factors.

METHODS

A retrospective review was performed of all 159 hand infections treated in the operating room over an 11-year period (1997-2007). Mean age overall was 40 years, mean inpatient length of stay was 4.9 days, and 115 of the 159 patients were male. Examined data included known risk factors for MRSA, including human immunodeficiency virus infection, diabetes mellitus, intravenous drug use, incarceration, and homelessness.

RESULTS

Forty-eight patients had surgery for hand infections due to CA-MRSA. The yearly proportion of CA-MRSA increased over the study period, and the risk of having an MRSA infection was 41% higher with each progressive calendar year during the study period relative to the apparent incidence of non-MRSA hand infections. Other factors associated with CA-MRSA were intravenous drug use, felon-type infection, and prior hand infection. Multivariable logistic regression identified intravenous drug use as a significant, independent risk factor for CA-MRSA hand infection.

CONCLUSIONS

The proportion of surgically treated hand infections due to CA-MRSA has increased during the last decade. Intravenous drug use was the only independent risk factor for CA-MRSA infections treated in the operating room at our institution.

Transmission of methicillin-resistant Staphylococcus aureus to household contacts

The frequency of and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) transmission from a MRSA index person to household contacts were assessed in this prospective study. Between January 2005 and December 2007, 62 newly diagnosed MRSA index persons (46 patients and 16 health care workers) and their 160 household contacts were included in the study analysis. Transmission of MRSA from an index person to household contacts occurred in nearly half of the cases (47%; n = 29). These 29 index persons together had 84 household contacts, of which two-thirds (67%; n = 56) became MRSA positive. Prolonged exposure time to MRSA at home was a significant risk factor for MRSA transmission to household contacts. In addition, MRSA colonization at least in the throat, younger age, and eczema in index persons were significantly associated with MRSA transmission; the presence of wounds was negatively associated with MRSA transmission. Furthermore, an increased number of household contacts and being the partner of a MRSA index person were household-related risk factors for MRSA acquisition from the index person. No predominant pulsed-field gel electrophoresis (PFGE) type was observed to be transmitted more frequently than other PFGE types. To date, screening household contacts and providing MRSA eradication therapy to those found positive simultaneously with the index person is not included in the "search-and-destroy" policy. We suggest including both in MRSA prevention guidelines, as this may reduce further spread of MRSA.