Intervention to Reduce the Incidence of Methicillin-ResistantStaphylococcus aureusSkin Infections in a Correctional Facility in Georgia

A hand-washing community-based educational intervention to reduce abscess incidence among people who inject drugs: a cluster randomised controlled clinical trial protocol (the HAWA study protocol)

BACKGROUND

Besides the high prevalence of HIV and HCV infections, people who inject drugs (PWID) have a cumulative risk of acquiring skin and soft tissue infections (SSTI) from, among other things, social precariousness, homelessness/unstable housing, and unhygienic injecting practices. We propose to evaluate whether a two-component educational hand hygiene intervention which combines training in hand-washing with the supply of a single-use alcohol-based hand rub, called MONO-RUB, is effective in reducing injection-related abscesses in the PWID population. Specifically, we shall implement a nationwide, two-arm, multi-centre, cluster randomised controlled trial to evaluate the effectiveness and cost-effectiveness of this intervention in PWID.

METHODS

HAWA is a community-based participatory research study to be conducted in 22 harm reduction centres (HR) in France (not yet recruiting); the latter will be randomised into two clusters: centres providing standard HR services and the intervention (i.e., intervention group) and those providing standard HR services only (i.e., control group). After randomization, each cluster will include 220 PWID, with an inclusion period of 12 months and an individual follow-up period of 6 months. For each participant, we will collect data at M0, M3 and M6 from photos of injection sites on the participant's body, a face-to-face injection-related SSTI questionnaire, and a CATI questionnaire. The primary outcome is the reduction in abscess prevalence between M0 and M6, which will be compared between the control and intervention arms, and measured from observed (photographs) and self-declared (SSTI questionnaire) data. We will also assess the cost-effectiveness of the intervention.

DISCUSSION

The HAWA trial will be the first cluster randomized controlled trial to improve hand hygiene among PWID with a view to reducing SSTI. If effective and cost-effective, the intervention combined with the distribution of MONO-RUBs (or a similar cleaning product) may prove to be an important HR tool, helping to reduce the enormous burden of infection-related deaths and diseases in PWID.

TRIAL REGISTRATION

NCT06131788, received on 2 January 2024.

A systematic scoping review of environmental health conditions in penal institutions

Adequate environmental health conditions in penal institutions are necessary to protect and promote the health of prisoners and prison workers. We conducted a scoping systematic review to: describe the environmental health conditions in penal institutions and the associated exposures and health outcomes; identify effective approaches to prevent environmental health concerns; and identify evidence gaps on environmental health in penal institution populations. PubMed, Web of Science, EBSCOhost, Scopus, and ProQuest were searched. Peer-reviewed studies that reported original data and on environmental health conditions and/or exposures in penal institutions were included. Seventy-three studies met these criteria. The most common risk factor identified was contaminated food and/or beverages prepared or handled in the institution's kitchen. Overcrowding, inadequate ventilation, and a lack of, or sharing of, soap and other hygiene products increased the risk of adverse health outcomes. Common responses included isolating infectious patients, educating prisoners and prison staff on improved sanitation and hygiene practices, improving ventilation, and disinfecting contaminated surfaces and/or water sources. Inadequate environmental health conditions in penal institutions are common, and adversely impact the health of prisoners and prison staff, yet are preventable. Few studies have been conducted in low- and middle-income countries, biasing our results. The development and implementation of national guidelines for essential environmental health in prisons, monitoring of conditions, and greater accountability of facility managers are needed to secure the health, rights, and well-being of prisoners.

Methicillin-resistant Staphylococcus aureus skin and soft tissue infections in young people in custody in New South Wales

AIM

Methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) are problematic for incarcerated adolescents but have not been previously researched.

METHODS

This was a 2-year prospective study of all New South Wales Juvenile Custodial Centres involving incarcerated youth aged 12-20 years. The main outcomes measured were MRSA SSTIs, MRSA molecular subtypes and associations with MRSA infection. Variables included age, gender, SSTI site and type, Indigenous status, incarceration time, lifetime incarcerations, intravenous drug use, overweight/obesity, recent antibiotic use and health centre presentations.

RESULTS

From February 2013 to January 2015, there were 77 SSTIs (92.2% male, 59.2% Indigenous, mean age 16.9 years). The majority (77.9%) were collections, mostly on the lower limb (44.2%), and 33 (42.9%) isolates were MRSA; 94% were Panton-Valentine leukocidin positive. This represents 11 SSTIs per 1000 custodial admissions, and 4.7 MRSA SSTIs per 1000 custodial admissions. Independent associations with MRSA SSTI (vs. non-MRSA SSTI) were Indigenous status (adjusted odds ratio (AOR) 5.92, P < 0.001), presenting with a collection (AOR 18.29, P < 0.001) and recent antibiotic use (AOR 3.62, P < 0.05).

CONCLUSIONS

Incarcerated Australian youth have high rates of MRSA SSTIs, comparable to rates in US adult inmates, but with different molecular subtypes. At particular risk of MRSA infection are Indigenous youth, those with recent antibiotic use and those presenting with a collection. Many MRSA infections present at custodial admission, making surveillance and containment important, along with avoidance of unnecessary antibiotics and hand hygiene. Panton-Valentine leukocidin-positive MRSA predominates and is known for causing flu-associated necrotising pneumonia. Albeit a rare outcome, the seasonal influenza vaccination should be mandatory for youth in custody and custodial staff.

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.

Epidemiological and biological determinants of Staphylococcus aureus clinical infection in New York State maximum security prisons

BACKGROUND

Large outbreaks of Staphylococcus aureus (SA) infections have occurred in correctional facilities across the country. We aimed to define the epidemiological and microbiological determinants of SA infection in prisons to facilitate development of prevention strategies for this underserved population.

METHODS

We conducted a case-control study of SA infection at 2 New York State maximum security prisons. SA-infected inmates were matched with 3 uninfected controls. Subjects had cultures taken from sites of infection and colonization (nose and throat) and were interviewed via structured questionnaire. SA isolates were characterized by spa typing. Bivariate and multivariable analyses were conducted using conditional logistic regression.

RESULTS

Between March 2011 and January 2013, 82 cases were enrolled and matched with 246 controls. On bivariate analysis, the use of oral and topical antibiotics over the preceding 6 months was strongly associated with clinical infection (OR, 2.52; P < .001 and 4.38, P < .001, respectively). Inmates with clinical infection had 3.16 times the odds of being diabetic compared with inmates who did not have clinical infection (P < .001). Concurrent nasal and/or oropharyngeal colonization was also associated with an increased odds of infection (OR, 1.46; P = .002). Among colonized inmates, cases were significantly more likely to carry the SA clone spa t008 (usually representing the epidemic strain USA300) compared to controls (OR, 2.52; P = .01).

CONCLUSIONS

Several inmate characteristics were strongly associated with SA infection in the prison setting. Although many of these factors were likely present prior to incarceration, they may help medical staff identify prisoners for targeted prevention strategies.

Chlorhexidine-Impregnated Cloths to Prevent Skin and Soft-Tissue Infection in Marine Recruits: A Cluster-Randomized, Double-Blind, Controlled Effectiveness Trial

Background.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) causes skin and soft-tissue infection (SSTI) in military recruits.

Objective.

To evaluate the effectiveness of 2% Chlorhexidine gluconate (CHG)-impregnated cloths in reducing rates of SSTI and S. aureus colonization among military recruits.

Design.

A cluster-randomized (by platoon), double-blind, controlled effectiveness trial.

Setting.

Marine Officer Candidate School, Quantico, Virginia, 2007.

Participants.

Military recruits.

Intervention.

Application of CHG-impregnated or control (Comfort Bath; Sage) cloths applied over entire body thrice weekly.

Measurements.

Recruits were monitored daily for SSTI. Baseline and serial nasal and/or axillary swabs were collected to assess S. aureus colonization.

Results.

Of 1,562 subjects enrolled, 781 (from 23 platoons) underwent CHG-impregnated cloth application and 781 (from 21 platoons) underwent control cloth application. The rate of compliance (defined as application of 50% or more of wipes) at 2 weeks was similar (CHG group, 63%; control group, 67%) and decreased over the 6-week period. The mean 6-week SSTI rate in the CHG-impregnated cloth group was 0.094, compared with 0.071 in the control group (analysis of variance model rate difference, 0.025 ± 0.016; P = .14). At baseline, 43% of subjects were colonized with methicillin-susceptible S. aureus (MSSA), and 2.1% were colonized with MRSA. The mean incidence of colonization with MSSA was 50% and 61% (P = .026) and with MRSA was 2.6% and 6.0% (P = .034) for the CHG-impregnated and control cloth groups, respectively.

Conclusions.

CHG-impregnated cloths applied thrice weekly did not reduce rates of SSTI among recruits. S. aureus colonization rates increased in both groups but to a lesser extent in those assigned to the CHG-impregnated cloth Intervention. Antecedent S. aureus colonization was not a risk factor for SSTI. Additional studies are needed to identify effective measures for preventing SSTI among military recruits.

Clinical Trials Registration.

ClinicalTrials.gov identifier: NCT00475930.

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 of and risk factors for methicillin-resistant Staphylococcus aureus colonization in HIV infection: a meta-analysis

BACKGROUND

Human immunodeficiency virus (HIV)-infected individuals who are colonized with methicillin-resistant Staphylococcus aureus (MRSA) have increased risk for MRSA infection. We conducted a meta-analysis of published studies to estimate the prevalence of MRSA colonization in this population.

METHODS

We performed a systematic literature review and meta-analysis. The PubMed and Embase databases were searched and studies reporting prevalence of MRSA colonization among HIV-infected individuals were included.

RESULTS

Among 7940 citations, 32 studies reporting data on 6558 HIV-infected individuals were considered eligible for our meta-analysis. We found that 6.9% (95% confidence interval [CI], 4.8-9.3) of individuals with HIV infection are MRSA carriers, with the corresponding figure across North American studies being 8.8% (95% CI, 6.0-12.2). History of hospitalization during the previous 12 months was associated with a 3.1 times higher risk of MRSA colonization (risk ratio [RR], 3.11 [95% CI, 1.62-5.98]). Previous or current incarceration was also associated with a higher risk for carriage (RR, 1.77 [95% CI, 1.26-2.48]). Current antiretroviral therapy or use of trimethoprim-sulfamethoxazole did not impact the risk of MRSA carriage (RR, 1.02 [95% CI, .64-1.63] and 1.45 [95% CI, .69-3.03], respectively). Extranasal screening increased the detection of MRSA colonization by at least 31.6% (95% CI, 15.8-50.0). The added yield from groin screening was 19.3% (95% CI, 11.5-28.5), from perirectal screening 18.5% (95% CI, 7.4-33.2), and from throat cultures 17.5% (95% CI, 12.0-24).

CONCLUSIONS

Individuals with HIV infection constitute a highly vulnerable population for MRSA colonization, and prior exposure to hospital or incarceration are significant factors. Nasal screening alone will underestimate the rate of colonization by at least one-third.

Hand and nasal carriage of discordant Staphylococcus aureus isolates among urban jail detainees

In 928 Dallas County Jail detainees, nasal carriage of Staphylococcus aureus was found in 32.8% (26.5% methicillin-susceptible Staphylococcus aureus [MSSA] and 6.3% methicillin-resistant S. aureus [MRSA]), and hand carriage was found in 24.9% (20.7% MSSA and 4.1% MRSA). Among MRSA nasal carriers, 41% had hand MRSA carriage; 29% with hand MRSA carriage had no nasal S. aureus carriage. The prevalence of carriage was not associated with duration of the jail stay up to 180 days.

Prevalence of chlorhexidine-resistant methicillin-resistant Staphylococcus aureus following prolonged exposure

Chlorhexidine has been increasingly utilized in outpatient settings to control methicillin-resistant Staphylococcus aureus (MRSA) outbreaks and as a component of programs for MRSA decolonization and prevention of skin and soft-tissue infections (SSTIs). The objective of this study was to determine the prevalence of chlorhexidine resistance in clinical and colonizing MRSA isolates obtained in the context of a community-based cluster-randomized controlled trial for SSTI prevention, during which 10,030 soldiers were issued chlorhexidine for body washing. We obtained epidemiological data on study participants and performed molecular analysis of MRSA isolates, including PCR assays for determinants of chlorhexidine resistance and high-level mupirocin resistance and pulsed-field gel electrophoresis (PFGE). During the study period, May 2010 to January 2012, we identified 720 MRSA isolates, of which 615 (85.4%) were available for molecular analysis, i.e., 341 clinical and 274 colonizing isolates. Overall, only 10 (1.6%) of 615 isolates were chlorhexidine resistant, including three from the chlorhexidine group and seven from nonchlorhexidine groups (P > 0.99). Five (1.5%) of the 341 clinical isolates and five (1.8%) of the 274 colonizing isolates harbored chlorhexidine resistance genes, and four (40%) of the 10 possessed genetic determinants for mupirocin resistance. All chlorhexidine-resistant isolates were USA300. The overall prevalence of chlorhexidine resistance in MRSA isolates obtained from our study participants was low. We found no association between extended chlorhexidine use and the prevalence of chlorhexidine-resistant MRSA isolates; however, continued surveillance is warranted, as this agent continues to be utilized for infection control and prevention efforts.

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.

Prevalence and risk factors for Staphylococcus aureus colonization in individuals entering maximum-security prisons

To assess the prevalence and risk factors for colonization with Staphylococcus aureus in inmates entering two maximum-security prisons in New York State, USA, inmates (N=830) were interviewed and anterior nares and oropharyngeal samples collected. Isolates were characterized using spa typing. Overall, 50·5% of women and 58·3% of men were colonized with S. aureus and 10·6% of women and 5·9% of men were colonized with MRSA at either or both body sites. Of MSSA isolates, the major subtypes were spa type 008 and 002. Overall, risk factors for S. aureus colonization varied by gender and were only found in women and included younger age, fair/poor self-reported general health, and longer length of prior incarceration. Prevalence of MRSA colonization was 8·2%, nearly 10 times greater than in the general population. Control of epidemic S. aureus in prisons should consider the constant introduction of strains by new inmates.

The rise of methicillin-resistant staphylococcus aureus in U.S. correctional populations

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging threat to public health, especially in correctional settings. Outbreaks have been seen in jails and prisons in Mississippi, California, Texas, and Georgia in recent years. Also, many correctional settings have seen an increase in MRSA infection greater than in the general population. This article examines the lessons that have been learned about MRSA in correctional settings and ponders what is yet to be learned about this disease in these populations.

Recent incarceration linked to cutaneous injection-related infections among active injection drug users in a Canadian setting

Cutaneous injection-related infections (CIRI), such as abscesses and cellulitis, are the cause of a substantial burden of morbidity and mortality among injection drug users (IDU). The possible contribution of exposure to correctional environments to CIRI risk has not been fully investigated. Thus, we sought to test the possible relationship between incarceration and CIRI using data from a community-based sample of IDU. Data for these analyses was from the Scientific Evaluation of Supervised Injecting (SEOSI) cohort, linked with administrative records of a local ED in Vancouver, Canada. Using longitudinal analysis we assessed the relationship between the number of ED visits for CIRI care and recent incarceration in a multivariate model including information on possible confounders. Between June 2004 and December 2006, 901 individuals were eligible for our analysis. Of these, 214 (9.6%) visited the ED for CIRI care at least once during the study period. The incidence of ED care for CIRI was 72.9 per 100 person years. In a multivariate model, recent incarceration was associated with a greater number of ED visits for CIRI care (adjusted relative rate = 1.56, 95% confidence interval: 1.31-1.85, P < 0.001). The need for ED treatment for CIRI was common among a sample of local IDU. Exposure to correctional environments was an independent risk factor for visiting the ED for CIRI care, suggesting improvements in infection control in local prisons is urgently needed.

Community-associated methicillin-resistant Staphylococcus aureus: epidemiology and clinical consequences of an emerging epidemic

Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention.

Treatment of community-associated methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus has emerged in the community among patient populations without traditional antibiotic resistance risk factors and is causing a variety of clinical syndromes, in particular skin and soft tissue infections. These infections can range from minor skin involvement that can be treated in an outpatient setting to more serious infections such as necrotizing fasciitis requiring hospitalization. Inpatient and outpatient healthcare providers must be aware of the treatment, prevention, and infection control practices for this emerging pathogen.

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.

Long-term follow-up of methicillin-resistant Staphylococcus aureus molecular epidemiology after emergence of clone USA300 in San Francisco jail populations

We performed a longitudinal analysis of 502 unique methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates originating from San Francisco jail inmates between 2000 and 2007. Strain USA300, first encountered in 2001, accounted for 82.1% (412/502) of MRSA infections. Non-USA300 MRSA strains were rarely found after 2005 (one isolate in 2006, three in 2007).

Treatment of community-associated methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus has emerged in the community among patient populations without traditional antibiotic resistance risk factors and is causing a variety of clinical syndromes, in particular skin and soft tissue infections. These infections can range from minor skin involvement that can be treated in an outpatient setting to more serious infections such as necrotizing fasciitis requiring hospitalization. Inpatient and outpatient healthcare providers must be aware of the treatment, prevention, and infection control practices for this emerging pathogen.

Modelling an outbreak of an emerging pathogen

To illustrate the usefulness of mathematical models to the microbiology and medical communities, we explain how to construct and apply a simple transmission model of an emerging pathogen. We chose to model, as a case study, a large (>8,000 reported cases) on-going outbreak of community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) in the Los Angeles County Jail. A major risk factor for CA-MRSA infection is incarceration. Here, we show how to design a within-jail transmission model of CA-MRSA, parameterize the model and reconstruct the outbreak. The model is then used to assess the severity of the outbreak, predict the epidemiological consequences of a catastrophic outbreak and design effective interventions for outbreak control.

Practical management: community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA): the latest sports epidemic

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has gained international recognition as a superbug that causes serious infectious outbreaks in high-risk populations such as athletes. Clusters of cases in various athletic teams, particularly contact sports, have been reported since 1993 in the United States and more recently in Canada. CA-MRSA infections are not limited to North America, and all athletes are considered high risk. Skin-to-skin contact appears to be the primary mode of transmission. While typical infections are local skin and soft-tissue abscesses, CA-MRSA infections can spread systemically and lead to significant morbidity and mortality if not promptly identified and treated. The gold standard of treatment for all abscesses is incision and drainage with wound culture for bacterial identification and antibiotic sensitivity testing. A limited number of antibiotics are currently useful in the treatment of CA-MRSA and are reviewed. Geographical variation in patterns of antibiotic resistance further complicates the treatment. Meticulous, consistent use of infection prevention strategies is critical to control outbreaks in the athletic population. Good hygiene, prompt identification of infection, limited exposure to infected persons and contaminated objects, and proper treatment combined with close follow-up of infected athletes will help contain CA-MRSA outbreaks. Future research is needed to explore person-to-person and fomite transmission risks, to define the significance of nasal carriage and skin colonization in relation to CA-MRSA infections, and to further investigate antibiotic resistance patterns. Universal education is needed for all athletes and personnel who provide care in the athletic setting to help control this widespread epidemic.

Emergency management of difficult wounds: part II

Difficult wounds constitute a significant amount of the morbidity and mortality emergency physicians face on a daily basis. There are specific traumatic and atraumatic wounds that are difficult to manage and have a high risk of complications. Emergency physicians must be able to identify these high-risk wounds and patients and take steps to mitigate further morbidity and mortality.

Meticillin-resistant Staphylococcus aureus among US prisoners and military personnel: review and recommendations for future studies

We reviewed published work examining the prevalence and risk factors for meticillin-resistant Staphylococcus aureus (MRSA) infection in two high-risk groups: prisoners and military enlistees. Significant risk factors for infection included prison occupation, gender, comorbidities, prior skin infection, and previous antibiotic use. Although characteristics such as hygiene, physical contact, and crowding were postulated as risk factors for MRSA infection, there were few epidemiological studies supporting these factors. Most studies identified were retrospective in design and only one study used prospective surveillance for MRSA colonisation among all individuals residing within a single military setting. Our results suggest that there is a high incidence of MRSA infection among individuals in prisons and military settings, but surveys that quantify the prevalence of MRSA colonisation among individuals living within these specialised settings are needed. A thorough examination of MRSA acquisition and transmission patterns in prisons and military settings could help elucidate preventive strategies in other crowded and closed settings.