Chlorhexidine gluconate reduces transmission of methicillin-resistant Staphylococcus aureus USA300 among Marine recruits

Diagnostic and Therapeutic Challenges in a Military Recruit Training Center of the Hellenic Navy: A Retrospective Analysis of the Poros Registry Serving as a Quality Improvement Project for Medical Officers

INTRODUCTION

Basic military training (BMT) has been associated with increased morbidity burden. Nevertheless, the exact epidemiology of the encountered cases in the BMT of Greek recruits has never been assessed. The aim of this quality improvement project was to investigate for the first time the clinical patterns, rates, and severity of symptoms leading recruits to visit the infirmary of a recruit training center and use this knowledge to provide a practical guidance for the physicians in charge.

MATERIALS AND METHODS

All medical cases which were consecutively examined for the time range from November 2021 to September 2022 at the infirmary of the Hellenic Naval recruit training center in Poros, Greece, were retrospectively analyzed. Logistic regression analyses were performed to identify independent predictors of "severe clinical status" (i.e., overnight sick bay confinement and/or transfer to a tertiary hospital within 24 h) and absence from BMT for at least 1 day.

RESULTS

A total of 2,623 medical cases were examined during four recruit seasons from November 2021 to September 2022. Upper respiratory tract infections (URTIs) and musculoskeletal injuries were the most frequent reasons for a recruit's visit to the infirmary (33.9% and 30.2%, respectively). 6.7% of the total cases were identified as having "severe clinical status." Specifically, in psychiatric, urological, and cardiovascular cases, febrile events were all independently associated with increased risk of "severe clinical status." There was a positive association between training week and absence from BMT, while febrile events and spring recruit season were also independently linked with increased probability of absence from BMT for at least 1 day.

CONCLUSIONS

URTIs and musculoskeletal complaints were the primary reasons for recruits' presentation at the infirmary of a Greek recruit training center, leading to severe rates of attrition. Further registries and quality improvement projects are warranted to reach specific conclusions and reduce BMT-related morbidity and its subsequent implications.

The Utility of Chlorhexidine Cloth Use for the Prevention of Surgical Site Infections in Total Hip Arthroplasty and Surgical as well as Basic Science Applications: A Meta-Analysis and Systematic Review

Skin antisepsis, such as ready-to-use, no-rinse, 2% chlorhexidine-impregnated cloths, is one of the fundamental cornerstones for reducing periprosthetic infections after primary lower extremity total joint arthroplasties. This systematic review presents background material concerning the problem and methods to deal with and then describes the use of chlorhexidine cloth prophylaxis related to various surgical applications. The authors found an almost universal benefit of the cloths. In the meta-analysis, the total pooled effect showed a reduction in infection rates. The use of chlorhexidine cloths is appropriate for prophylaxis for knee arthroplasty, hip arthroplasty, and a variety of other surgeries.

Opportunities and Obstacles in the Prevention of Skin and Soft-Tissue Infections Among Military Personnel

INTRODUCTION

Skin and soft-tissue infections (SSTIs) are an important cause of infectious disease morbidity among military populations. Due to the high direct and indirect costs associated with SSTIs, particularly with methicillin-resistant Staphylococcus aureus (MRSA) infections, there remains a critical need for the development and evaluation of SSTI prevention strategies among high-risk military personnel. Herein, we review efforts of the Infectious Disease Clinical Research Program (IDCRP) related to the prevention of SSTIs in the military.

METHODS

The IDCRP of the Uniformed Services University has conducted clinical research protocols on SSTI epidemiology and prevention among military personnel since 2009. Observational studies have examined the epidemiology of Staphylococcus aureus colonization and SSTI in training and deployment settings. Two randomized controlled trials of personal hygiene strategies for SSTI prevention at Marine Corps Base Quantico (Virginia) and Fort Benning (Georgia) were performed. Lastly, two vaccine trials have been conducted by the IDCRP, including a Phase 2 S. aureus vaccine trial (currently ongoing) among military trainees.

RESULTS

Military recruits and deployed personnel experience an intense and prolonged exposure to S. aureus, the major causative agent of SSTI. The burden of S. aureus colonization and SSTI is particularly high in military trainees. Hygiene-based trials for S. aureus decolonization among military trainees were not effective in reducing rates of SSTI. In January 2018, the IDCRP initiated a Phase 2 S. aureus vaccine trial among the US Army Infantry training population at Fort Benning.

CONCLUSIONS

In the military, a disproportionate burden of SSTIs is borne by the recruit population. Strategies relying upon routine application of agents for S. aureus decolonization have not been effective in preventing SSTIs. A novel S. aureus vaccine candidate is being currently evaluated in a military training population and may represent a new opportunity to prevent SSTIs for the military.

Vaccination with the Staphylococcus aureus secreted proteins EapH1 and EapH2 impacts both S. aureus carriage and invasive disease

INTRODUCTION

There is a need for an efficacious vaccine reducing infections due to Staphylococcus aureus, a common cause of community and hospital infection. Infecting organisms originate from S. aureus populations colonising the nares and bowel. Antimicrobials are widely used to transiently reduce S. aureus colonisation prior to surgery, a practice which is selecting for resistant S. aureus isolates. S. aureus secretes multiple proteins, including the protease inhibitors extracellular adhesion protein homologue 1 and 2 (EapH1 and EapH2).

METHODS

Mice were vaccinated intramuscularly or intranasally with Adenovirus serotype 5 and Modified Vaccinia Ankara viral vectors expressing EapH1 and EapH2 proteins, or with control viruses. Using murine S. aureus colonisation models, we monitored S. aureus colonisation by sequential stool sampling. Monitoring of S. aureus invasive disease after intravenous challenge was performed using bacterial load and abscess numbers in the kidney.

RESULTS

Intramuscular vaccination with Adenovirus serotype 5 and Modified Vaccinia Ankara viral vectors expressing EapH1 and EapH2 proteins significantly reduces bacterial recovery in the murine renal abscess model of infection, but the magnitude of the effect is small. A single intranasal vaccination with an adenoviral vaccine expressing these proteins reduced S. aureus gastrointestinal (GI) tract colonisation.

CONCLUSION

Vaccination against EapH1 / EapH2 proteins may offer an antibiotic independent way to reduce S. aureus colonisation, as well as contributing to protection against S. aureus invasive disease.

Tolerance of MRSA ST239-TW to chlorhexidine-based decolonization: Evidence for keratinocyte invasion as a mechanism of biocide evasion

OBJECTIVES

Information on genetic determinants of chlorhexidine tolerance (qacA carriage and MIC) in vitro is available, although evidence of the clinical impact and mechanisms remain poorly understood. We investigated why, following chlorhexidine intervention, prevalent epidemic MRSA ST22 and ST36 clones declined at an ICU, whilst an ST239-TW clone did not. The chlorhexidine tolerant ST239-TW phenotypes were assessed for their protein binding, cell adhesion and intracellular uptake potential.

METHODS

Six ST22, ST36 and ST239-TW bloodstream infection isolates with comparable chlorhexidine MICs were selected from a 2-year outbreak in an ICU at Guy's and St. Thomas' Hospital. Isolates were tested for fibrinogen and fibronectin binding, and adhesion/internalization into human keratinocytes with and without biocide.

RESULTS

Binding to fibrinogen and fibronectin, adhesion and intracellular uptake within keratinocytes (P < 0.001) and intracellular survival in keratinocytes under chlorhexidine pressure (ST22 3.18%, ST36 4.57% vs ST239-TW 12.79%; P < 0.0001) was consistently higher for ST239-TW.

CONCLUSIONS

We present evidence that MRSA clones with similarly low in vitro tolerance to chlorhexidine exhibit different in vivo susceptibilities. The phenomenon of S. aureus adhesion and intracellular uptake into keratinocytes could therefore be regarded as an additional mechanism of chlorhexidine tolerance, enabling MRSA to evade infection control measures.

Routine chlorhexidine gluconate use onboard navy surface vessels to reduce infection: A cluster randomized controlled trial

BACKGROUND

Hand disinfection with chlorhexidine gluconate (CHG) is commonly used for preventing the spread of infection in medical institutions and the community, but studies on its use in military settings have been inconclusive. We examined the effects of CHG on morbidity in Israeli Navy ships.

METHODS

This was a controlled, cluster randomized study that took place at a major naval base in Israel. Ships were randomly selected into the study (347 sailors) and primary control (350 sailors) groups. Additional nonintervention control groups included other sailors serving on the base (n = 360) and logistics and support personnel (n = 859). CHG disinfection devices were installed on all ships in the study group, alongside soap and water. Morbidity was analyzed using a computerized patient record, subjective self-report questionnaires, and a sample of hand cultures. Compliance with hand hygiene was analyzed using a self-report hygiene attitudes questionnaire at the beginning of the trial and after 3 months. The study took place between May and September 2014.

RESULTS

No significant differences were found between the groups in terms of sick days or light-duty days or in the number of acute gastrointestinal or respiratory cases. Sailors were found to have more skin infections than controls, but this was not significantly reduced by CHG. Hand cultures demonstrated that continuous use of CHG did not cause a reduction in colonization. There were no statistically significant differences in self-reported hygiene practices.

CONCLUSIONS

CHG did not demonstrate any medical benefit over the use of soap and water onboard Israeli Navy ships.

Risk factors for dermatitis in submariners during a submerged patrol: an observational cohort study

OBJECTIVE

The aim of this pilot study was to determine risk factors, including Staphylococcus aureus nasal carriage, for dermatitis in submariners during a submarine patrol.

PARTICIPANTS AND METHODS

36 submariners undertaking a submerged 6-week patrol participated in the study. Severity of dermatitis and its impact was assessed using visual analogue scales and questionnaires at baseline and weekly throughout the patrol. S. aureus carriage levels in submariners were determined by nasal swabbing at baseline and shortly before disembarking the submarine. Occurrence of any skin or soft tissue infections (SSTI) were reported to the medical officer and swabs of the area were taken for subsequent analysis.

RESULTS

S. aureus carriers were significantly more likely than non-carriers to have previously received treatment for a cutaneous abscess (39% vs 5%, OR=13 (95% CI 1.3 to 130)) with a trend to being submariners longer (p=0.051). Skin scores at baseline and on patrol were not significantly associated with carriage status. Higher dermatitis scores were observed in those who had been submariners longer (p=0.045). Smoking and allergies were not found to be linked to carriage status or skin health score in this cohort.

CONCLUSIONS

This small pilot study investigates S. aureus carriage status and skin health in submariners. Length of submarine service but not S. aureus carriage was identified as a risk factor for worsening skin health in this small cohort during a 6-week patrol. This does not support S. aureus decolonisation to improve skin health in this population. Further investigation into causes of dermatitis in submariners is required. This data supports a better understanding of the potential impact of exposure to environmental factors that could affect skin health in submariners.

Recurrent Methicillin-Resistant Staphylococcus aureus Cutaneous Abscesses and Selection of Reduced Chlorhexidine Susceptibility during Chlorhexidine Use

We describe the selection of reduced chlorhexidine susceptibility during chlorhexidine use in a patient with two episodes of cutaneous USA300 methicillin-resistant Staphylococcus aureus abscess. The second clinical isolate harbors a novel plasmid that encodes the QacA efflux pump. Greater use of chlorhexidine for disease prevention warrants surveillance for resistance.

A randomized, controlled trial of chlorhexidine-soaked cloths to reduce methicillin-resistant and methicillin-susceptible Staphylococcus aureus carriage prevalence in an urban jail

OBJECTIVE

To assess an intervention to limit community-associated methicillin-resistant Staphylococcus aureus (MRSA) dissemination.

DESIGN

Randomized, controlled trial.

SETTING

County Jail, Dallas, Texas.

PARTICIPANTS

A total of 4,196 detainees in 68 detention tanks.

METHODS

Tanks were randomly assigned to 1 of 3 groups: in group 1, detainees received cloths that contained chlorhexidine gluconate (CHG) to clean their entire skin surface 3 times per week for 6 months; group 2 received identical cloths containing only water; and group 3 received no skin treatment. During the study, all newly arrived detainees were invited to enroll. Nares and hand cultures were obtained at baseline and from all current enrollees at 2 and 6 months.

RESULTS

At baseline, S. aureus was isolated from 41.2% and MRSA from 8.0% (nares and/or hand) of 947 enrollees. The average participation rate was 47%. At 6 months, MRSA carriage was 10.0% in group 3 and 8.7% in group 1 tanks (estimated absolute risk reduction [95% confidence interval (CI)], 1.4% [-4.8% to 7.1%]; P = .655). At 6 months, carriage of any S. aureus was 51.1% in group 3, 40.7% in group 1 (absolute risk reduction [95% CI], 10.4% [0.01%-20.1%]; P = .047), and 42.8% (absolute risk reduction [95% CI], 8.3% [-1.4% to 18.0%]; P = .099) in group 2.

CONCLUSIONS

Skin cleaning with CHG for 6 months in detainees, compared with no intervention, significantly decreased carriage of S. aureus, and use of water cloths produced a nonsignificant but similar decrease. A nonsignificant decrease in MRSA carriage was found with CHG cloth use.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT00785200.

Staphylococcus aureus skin infection recurrences among household members: an examination of host, behavioral, and pathogen-level predictors

BACKGROUND

Many patients suffer from recurrent Staphylococcus aureus infections, but there are few data examining recurrence predictors.

METHODS

We followed adults and children after treatment for S. aureus skin infections and their household contacts in Los Angeles and Chicago. We surveyed subjects for S. aureus body colonization, household fomite contamination, and behavioral and clinical factors at baseline and 3 and 6 months later. Using repeated measures modeling, we examined host, pathogen, behavioral, and clinical factors associated with recurrence.

RESULTS

Among 330 index subjects, 182 (55%) were infected with an isolate of the USA300 methicillin-resistant S. aureus (MRSA) genetic background. Recurrences occurred in 39% by month 3 and 51% by month 6. Among 588 household contacts, 10% reported a skin infection by month 3 and 13% by month 6. Among index subjects, recurrence was associated with (P < .05) Los Angeles site, diabetes, recent hospitalization, recent skin infection, recent cephalexin use, and household S. aureus or MRSA fomite contamination; recurrence was inversely associated with recent contact sports participation. In the multivariate model, independent predictors of recurrence in index patients were recent hospitalization, household MRSA fomite contamination, and lack of recent contact sports participation. Among household contacts, independent predictors of subsequent skin infection were Chicago site, antibiotic use in the prior year, and skin infection in the prior 3 months.

CONCLUSIONS

In our longitudinal study, patients with a S. aureus skin infection were more likely to suffer a recurrence if household fomites were MRSA contaminated. Interventions to prevent recurrence may be enhanced by decontamination of household fomites.

Frequent use of chlorhexidine-based body wash associated with a reduction in methicillin-resistant Staphylococcus aureus nasal colonization among military trainees

In a field-based trial among military trainees, personal hygiene measures, including chlorhexidine (CHG) body wash, did not prevent overall and methicillin-resistant Staphylococcus aureus (MRSA) skin and soft-tissue infections (SSTI). We conducted a secondary analysis of anterior nares cultures obtained during the trial to evaluate the impact of hygiene measures on Staphylococcus aureus colonization. A cluster-randomized trial for SSTI prevention was conducted among U.S. Army infantry trainees from May 2010 to January 2012. There were three study groups with incrementally increasing education- and hygiene-based components: standard (S), enhanced standard (ES), and CHG. Anterior nares cultures were obtained from participants to determine the prevalence of S. aureus colonization. A total of 1,706 participants (469 S, 597 ES, and 640 CHG) without SSTI were included in the colonization analysis. Of those randomized to the CHG group, 360 (56.3%) reported frequent use of body wash. Frequent use of body wash had no effect on overall S. aureus colonization (53.3% versus 56.8% among infrequent/nonusers; P=0.25). MRSA colonization prevalence was marginally lower among frequent users (2.5% versus 4.7%; P=0.07). In multivariable analysis, the odds of MRSA colonization were lower among frequent users (odds ratio [OR], 0.36; 95% confidence interval [CI], 0.16 to 0.77). This CHG-associated reduction was not observed when comparing colonization with USA300 to that with non-USA300 types (OR, 0.59; 95% CI, 0.06 to 5.76). Frequent use of CHG body wash was associated with a reduction in MRSA nasal colonization among high-risk military trainees. Topical chlorhexidine may contribute to MRSA SSTI prevention by reducing colonization. However, further studies evaluating the pathogenesis of SSTI are needed. (This study has been registered at ClinicalTrials.gov under registration no. NCT01105767).

Prevalence and characterization of methicillin-resistant Staphylococcus aureus isolates from healthy university student athletes

BACKGROUND

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has been increasing in the general population, and there is concern that close or physical contact, such as in professional and collegiate sports, may increase spread of MRSA. We sought to determine the prevalence of MRSA colonization of male and female athletes from 9 different sports at a major, Division I University during a 12-week period, and determine the USA and SCCmec type from select isolates.

METHODS

Swabs for culture of MRSA were obtained from nasal, axillary, and inguinal sites from healthy, asymptomatic student athletes and support staff each week for 12 weeks. Select MRSA isolates were typed by pulsed field gel electrophoresis (PFGE), and the genes encoding for MecA, cassette chromosome recombinase (Ccr), and several toxins were determined by multiplex polymerase chain reaction (PCR). Discrepant results were clarified by multi-locus sequence typing (MLST) and spa typing.

RESULTS

Thirty-five percent (78/223) of test subjects were positive for MRSA during the study period, resulting in isolation of 139 MRSA isolates. However, 47% (37/78) of MRSA-positive participants carried MRSA in axillary or inguinal sites, but not in the anterior nares. There was significant correlation between MRSA carriage and participation in wrestling (76%, 19/25; adjusted odds ratio 29.7, 95% CI 5.8-151.5) and baseball (44%, 17/39; adjusted odds ratio 4.4, 95% CI 1.1- 17.4), compared with a staff prevalence of 18.1% (4/22), but other factors were not examined. Multiplex PCR analysis indicated that of the 32 isolates examined 26 could be typed, and all of these carried the SCCmec type IV cassette. PFGE typing identified USA types 300, 400, 500, 700, and 800. However, one isolate was not a known USA type, but was identified as a novel ST951 by MLST, and as spa type t216. Of the strains typed from the same individual, there was consistency, but also variation and alternation of the SCCmec and spa types isolated from individual subjects. Various staphylococcal toxin genes were identified in 31 of the 32 isolates analyzed.

CONCLUSIONS

Colonization by MRSA was greater in some student athletes than the average carriage rate for the general population, and only 53% of MRSA carriers were identified by nasal cultures. Carriage of MRSA clones on the same individual and transmission to contacts could vary over time, indicating colonization can be a dynamic process that may be difficult to control.

Hygiene strategies to prevent methicillin-resistant Staphylococcus aureus skin and soft tissue infections: a cluster-randomized controlled trial among high-risk military trainees

BACKGROUND

Effective measures are needed to prevent methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) in high-risk community settings. The study objective was to evaluate the effect of personal hygiene-based strategies on rates of overall SSTI and MRSA SSTI.

METHODS

We conducted a prospective, field-based, cluster-randomized trial in US Army Infantry trainees from May 2010 through January 2012. There were 3 study groups with incrementally increased education and hygiene-based interventions: standard (S), enhanced standard (ES), and chlorhexidine (CHG). The primary endpoints were incidence of overall SSTI and MRSA SSTI.

RESULTS

The study included 30 209 trainees constituting 540 platoons (168 S, 192 ES, and 180 CHG). A total of 1203 (4%) participants developed SSTI, 316 (26%) due to MRSA. The overall SSTI rate was 4.15 (95% confidence interval [CI], 3.77-4.58) per 100 person-cycles. SSTI rates by study group were 3.48 (95% CI, 2.87-4.22) for S, 4.18 (95% CI, 3.56-4.90) for ES, and 4.71 (95% CI, 4.03-5.50) for CHG. The MRSA SSTI rate per 100 person-cycles for all groups was 1.10 (95% CI, .91-1.32). MRSA SSTI rates by study group were 1.0 (95% CI, .70-1.42) for S, 1.29 (95% CI, .98-1.71) for ES, and 0.97 (95% CI, .70-1.36) for CHG.

CONCLUSIONS

Personal hygiene and education measures, including once-weekly use of chlorhexidine body wash, did not prevent overall SSTI or MRSA SSTI in a high-risk population of military trainees.

CLINICAL TRIALS REGISTRATION

NCT01105767.

Detection of methicillin-resistant and methicillin-susceptible Staphylococcus aureus colonization of healthy military personnel by traditional culture, PCR, and mass spectrometry

BACKGROUND

Methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus colonization is associated with increased rates of infection. Rapid and reliable detection methods are needed to identify colonization of nares and extra-nare sites, particularly given recent reports of oropharynx-only colonization. Detection methods for MRSA/MSSA colonization include culture, PCR, and novel methods such as PCR/electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS).

METHODS

We evaluated 101 healthy military members for S. aureus colonization in the nares, oropharynx, axilla, and groin, using CHROMagar S. aureus medium and Xpert SA Nasal Complete PCR for MRSA/MSSA detection. The same subjects were screened in the nares, oropharynx, and groin using PCR/ESI-TOF-MS.

RESULTS

By culture, 3 subjects were MRSA-colonized (all oropharynx) and 34 subjects were MSSA-colonized (all 4 sites). PCR detected oropharyngeal MRSA in 2 subjects, which correlated with culture findings. By PCR, 47 subjects were MSSA-colonized (all 4 sites); however, 43 axillary samples were invalid, 39 of which were associated with deodorant/anti-perspirant use (93%, p < 0.01). By PCR/ESI-TOF-MS, 4 subjects were MRSA-colonized, 2 in the nares and 2 in the oropharynx; however, neither of these correlated with positive MRSA cultures. Twenty-eight subjects had MSSA by PCR/ESI-TOF-MS, and 41 were found to have possible MRSA (S. aureus with mecA and coagulase-negative Staphylococcus (CoNS)).

CONCLUSION

The overall 3% MRSA colonization rate is consistent with historical reports, but the oropharynx-only colonization supports more recent findings. In addition, the use of deodorant/anti-perspirant invalidated axillary PCR samples, limiting its utility. Defining MRSA positivity by PCR/ESI-TOF-MS is complicated by co-colonization of S. aureus with CoNS, which can also carry mecA.

The value of chlorhexidine gluconate wipes and prepacked washcloths to prevent the spread of pathogens--a systematic review

BACKGROUND

Use of chlorhexidine gluconate wipes and pre-packed washcloths has been described for preventing pathogen spread in healthcare settings.

AIM

To assess the impact of chlorhexidine washcloths/wipes in preventing the spread of pathogens.

METHODS

Extensive and structured literature search from studies in Google Academic, Cochrane Library, Web of Science, Pubmed and Cinahl from their inception until November 2012.

FINDINGS

Final analysis included 15 studies, 9 of which were randomised controlled trials. The most frequent setting was the intensive care unit. In intensive care units, a significant reduction of bloodstream infection was associated with intervention and 3 studies revealed a decrease in blood culture contamination. One study showed a decrease in staff and environmental contamination and no increase in chlorhexidine resistance with intervention. Positive blood cultures for multiple pathogens also declined with intervention. In a paediatric intensive care unit, intervention decreased bacteraemia and catheter-associated bloodstream infection. In hospital wards, intervention was associated to a 64% reduction of pathogen transmission. One study had no statistically significant results. Pre-surgical chlorhexidine use significantly decreased bacterial colonisation but had no impact on surgical site infections. Regarding maternal and perinatal setting, one study did not show reduction of early onset neonatal sepsis and pathogen transmission. Another study of vaginal and neonatal decolonisation with chlorhexidine wiping revealed significant reduction in colonisation. One study concluded that single and multiple umbilical cord cleansing reduced the likelihood for a positive swab in 25% and 29%, respectively. Neonatal wiping maintained low levels of skin colonisation for a 24h period, for multiple pathogens.

CONCLUSION

Current evidence supports the usefulness of chlorhexidine washcloths and wipes in an intensive care, hospital and pre-surgical setting. More studies are required to encourage its use for prevention of perinatal and neonatal transmission of pathogens.

Methicillin-resistant staphylococci: implications for our food supply?

Food-borne intoxication, caused by heat-stable enterotoxins produced by Staphylococcus aureus, causes over 240,000 cases of food-borne illness in the United States annually. Other staphylococci commonly associated with animals may also produce these enterotoxins. Foods may be contaminated by infected food handlers during slaughter and processing of livestock or by cross-contamination during food preparation. S. aureus also causes a variety of mild to severe skin and soft tissue infections in humans and other animals. Antibiotic resistance is common in staphylococci. Hospital-associated (HA) S. aureus are resistant to numerous antibiotics, with methicillin-resistant S. aureus (MRSA) presenting significant challenges in health care facilities for over 40 years. During the mid-1990s new human MRSA strains developed outside of hospitals and were termed community-associated (CA). A few years later, MRSA was isolated from horses and methicillin resistance was detected in Staphylococcus intermedius/pseudintermedius from dogs and cats. In 2003, a livestock-associated (LA) MRSA strain was first detected in swine. These methicillin-resistant staphylococci pose additional food safety and occupational health concerns. MRSA has been detected in a small percentage of retail meat and raw milk samples indicating a potential risk for food-borne transmission of MRSA. Persons working with animals or handling meat products may be at increased risk for antibiotic-resistant infections. This review discusses the scope of the problem of methicillin-resistant staphylococci and some strategies for control of these bacteria and prevention of illness.