Carey D. Schlett

Postinfectious Irritable Bowel Syndrome—A Meta-Analysis

OBJECTIVES:Irritable bowel syndrome (IBS) is a heterogeneous disorder affecting 12% of the population worldwide. Several studies identify IBS as a sequela of infectious gastroenteritis (IGE) with reported prevalence ranging from 4% to 31% and relative risk from 2.5 to 11.9. This meta-analysis was conducted to explore the differences between reported rates and provide a pooled estimate of risk for postinfectious irritable bowel syndrome (PI-IBS).DATA SOURCES:Electronic databases (MEDLINE, OLDMEDLINE, EMBASE, Cochrane database of clinical trials) and pertinent reference lists (including other review articles).REVIEW METHODS:Data were abstracted from included studies by two independent investigators; study quality, heterogeneity, and publication bias were assessed; sensitivity analysis was performed; and a summative effect estimate was calculated for risk of PI-IBS.RESULTS:Eight studies were included for analysis and all reported elevated risk of IBS following IGE. Median prevalence of IBS in the IGE groups was 9.8% (IQR 4.0–13.3) and 1.2% in control groups (IQR 0.4–1.8) (sign-rank test, p = 0.01). The pooled odds ratio was 7.3 (95% CI, 4.7–11.1) without significant heterogeneity (χ2 heterogeneity statistic, p = 0.41). Subgroup analysis revealed an association between PI-IBS risk and IGE definition used.CONCLUSIONS:This study provides supporting evidence for PI-IBS as a sequela of IGE and a pooled risk estimate revealing a sevenfold increase in the odds of developing IBS following IGE. The results suggest that the long-term benefit of reduced PI-IBS may be gained from primary prevention of IGE.

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.

Correlation between Nasal Microbiome Composition and Remote Purulent Skin and Soft Tissue Infections

ABSTRACT The incidence of skin and soft tissue infections (SSTIs) has increased dramatically over the past decade, resulting in significant morbidity in millions of otherwise healthy individuals worldwide. Certain groups, like military personnel, are at increased risk for SSTI development. Although nasal colonization with Staphylococcus aureus is an important risk factor for the development of SSTIs, it is not clear why some colonized individuals develop disease while others do not. Recent studies have revealed the importance of microbial diversity in human health. Therefore, we hypothesized that the nasal microbiome may provide valuable insight into SSTI development. To examine this hypothesis, we obtained anterior-naris samples from military trainees with cutaneous abscesses and from asymptomatic (non-SSTI) participants. We also obtained samples from within abscess cavities. Specimens were analyzed by culture, and the microbial community within each sample was characterized using a 16S sequencing-based approach. We collected specimens from 46 non-SSTI participants and from 40 participants with abscesses. We observed a significantly higher abundance of Proteobacteria in the anterior nares in non-SSTI participants (P < 0.0001) than in participants with abscesses. Additionally, we noted a significant inverse correlation between Corynebacterium spp. and S. aureus (P = 0.0001). The sensitivity of standard microbiological culture for abscesses was 71.4%. These data expand our knowledge of the complexity of the nasal and abscess microbiomes and potentially pave the way for novel therapeutic and prophylactic countermeasures against SSTI.

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 of Chlorhexidine-Resistant Methicillin-Resistant Staphylococcus aureus following Prolonged Exposure

ABSTRACT 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.

Chlorhexidine Gluconate Reduces Transmission of Methicillin-Resistant Staphylococcus aureus USA300 among Marine Recruits

BACKGROUND Methicillin-resistant Staphylococcus aureus (MRSA) pulsed-field type (PFT) USA300 causes skin and soft tissue infections in military recruits and invasive disease in hospitals. Chlorhexidine gluconate (CHG) is used to reduce MRSA colonization and infection. The impact of CHG on the molecular epidemiology of MRSA is not known. OBJECTIVE To evaluate the impact of 2% CHG-impregnated cloths on the molecular epidemiology of MRSA colonization. DESIGN Cluster-randomized, double-blind, controlled trial. SETTING Marine Officer Candidate School, Quantico, Virginia, in 2007. PARTICIPANTS Military recruits. INTERVENTION Thrice-weekly application of CHG-impregnated or control (Comfort Bath; Sage) cloths over the entire body. MEASUREMENTS Baseline and serial (every 2 weeks) nasal and/or axillary swab samples were assessed for MRSA colonization. Molecular analysis was performed with pulsed-field gel electrophoresis. RESULTS During training, 77 subjects (4.9%) acquired MRSA, 26 (3.3%) in the CHG group and 51 (6.5%) in the control group (P=.004). When analyzed for PFT, 24 subjects (3.1%) in the control group but only 6 subjects (0.8%) in the CHG group (P=.001) had USA300. Of the 167 colonizing isolates recovered from 77 subjects, 99 were recovered from the control group, including USA300 (40.4%), USA800 (38.4%), USA1000 (12.1%), and USA100 (6.1%), and 68 were recovered from the CHG group, including USA800 (51.5%), USA100 (23.5%), and USA300 (13.2%). CONCLUSIONS CHG decreased the transmission of MRSA--more specifically, USA300--among military recruits. In addition, USA300 and USA800 outcompeted other MRSA PFTs at incident colonization. Future studies should evaluate the broad-based use of CHG to decrease transmission of USA300 in hospital settings.

Prevalence of nasal colonization and strain concordance in patients with community-associated Staphylococcus aureus skin and soft-tissue infections.

OBJECTIVE Determine the prevalence and relatedness of Staphylococcus aureus anterior nares colonization in individuals with community-associated staphylococcal skin and soft-tissue infection (SSTI). DESIGN Observational cohort. SETTING US Army soldiers undergoing infantry training. PARTICIPANTS Trainees who developed SSTI from May 2010 to January 2012. METHODS Participants underwent anterior nares culture at the time of presentation for purulent SSTI. We determined the prevalence of S. aureus nasal colonization and strain relatedness between colonizing and clinical isolates with pulsed-field gel electrophoresis (PFGE). RESULTS We enrolled 1,203 SSTI participants, of whom 508 had culture-confirmed S. aureus SSTI. Overall, 70% (357/508) were colonized with S. aureus. Phenotypically, concordant colonization was more common with methicillin-susceptible S. aureus (MSSA; 56%; 122/218) than methicillin-resistant S. aureus (MRSA) SSTI (41%; 118/290; P < .01). With PFGE, 48% (121 of 254) of clinical-colonizing pairs were indistinguishable, and concordant colonization was more common with MRSA (53%; 92/173) than MSSA SSTI (36%; 29/81; P < .01). Restricting analysis to concomitant MRSA-MRSA or MSSA-MSSA pairs, 92% (92/100) of MRSA SSTI were indistinguishable, and 40% (29/72) MSSA SSTI were indistinguishable (P < .01). All 92 MRSA pairs were USA300. CONCLUSIONS On the phenotypic level, concordant anterior nares colonization with incident staphylococcal SSTI is more common in MSSA than MRSA; however, the opposite is observed when accounting for molecular typing, and MRSA SSTI displays greater concordance. USA300 was responsible for strain concordance with MRSA SSTI. Studies are needed to examine the roles of nasal and extra-nasal carriage, colonization preceding infection, and increased virulence in the pathogenesis of MRSA SSTI. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT01105767.

Outcomes of diarrhea management in operations Iraqi Freedom and Enduring Freedom

INTRODUCTION Among deployed U.S. military personnel, a sub-population of international travelers, acute infectious diarrhea continues to be a leading cause of morbidity and a potential threat to military effectiveness. METHODS To assess outcomes and satisfaction of diarrhea management in the field, a systematic survey was given to military personnel during mid- or post-deployment from Iraq or Afghanistan, from January through August 2004. RESULTS Sixty-three percent of those surveyed reported at least one episode of diarrhea, while less than half sought care for their symptoms. Overall, trends of decreased post-treatment duration were noted as travelers diarrhea therapy modalities grew more complex, controlling for severity of illness at presentation. Among those reporting diarrhea, the greatest level of satisfaction was seen in treatment with IV fluids (59%) followed by antibiotics (46%) and loperamide (40%). The greatest amount of dissatisfaction was seen in treatments with oral fluids only. CONCLUSION While current standard of care is self-treatment of diarrhea in civilian travelers, the U.S. military lacks standards outlining self-treatment of personnel at the individual level. Further research is needed to develop treatment guidelines on diarrhea management during military deployment.

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

ABSTRACT 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.

Evaluation of Methicillin-Resistant Staphylococcus aureus Skin and Soft-Tissue Infection Prevention Strategies at a Military Training Center

Military trainees are at high risk for skin and soft-tissue infections (SSTIs), especially those caused by methicillin-resistant Staphylococcus aureus (MRSA). A multicomponent hygiene-based SSTI prevention strategy was implemented at a military training center. After implementation, we observed 30% and 64% reductions in overall and MRSA-associated SSTI rates, respectively.