Genital Chlamydia trachomatis infection is the most commonly diagnosed sexually transmitted infection. Trachoma is caused by ocular infection with C trachomatis and is the leading infectious cause of blindness worldwide. New serological assays for C trachomatis could facilitate improved understanding of C trachomatis epidemiology and prevention. C trachomatis serology offers a means of investigating the incidence of chlamydia infection and might be developed as a biomarker of scarring sequelae, such as pelvic inflammatory disease. Therefore, serological assays have potential as epidemiological tools to quantify unmet need, inform service planning, evaluate interventions including screening and treatment, and to assess new vaccine candidates. However, questions about the performance characteristics and interpretation of C trachomatis serological assays remain, which must be addressed to advance development within this field. In this Personal View, we explore the available information about C trachomatis serology and propose several priority actions. These actions involve development of target product profiles to guide assay selection and assessment across multiple applications and populations, establishment of a serum bank to facilitate assay development and evaluation, and development of technical and statistical methods for assay evaluation and analysis of serological findings. The field of C trachomatis serology will benefit from collaboration across the public health community to align technological developments with their potential applications.

Chlamydia trachomatis (CT) serological assays with improved sensitivity over commercially available assays are needed to evaluate the burden of CT infection and effectiveness of prevention efforts. We evaluated the performance of a CT outer membrane complex protein B (OmcB) ELISA in the detection of anti-CT antibody responses in CT-infected women. OmcB ELISA was less sensitive than our CT elementary body (EB ELISA), but was highly specific. The magnitude of the antibody response was higher in African Americans and those with prior CT infection. Unlike EB ELISA, the IgG1 response to CT OmcB was short-lived and not maintained by repeat CT infection.

BACKGROUND: Chlamydia trachomatis infection is highly prevalent among young women in the United States. Prevention of long-term sequelae of infection, including tubal factor infertility, is a primary goal of chlamydia screening and treatment activities. However, the population attributable fraction of tubal factor infertility associated with chlamydia is unclear, and optimal measures for assessing tubal factor infertility and prior chlamydia in epidemiologic studies have not been established. Black women have increased rates of chlamydia and tubal factor infertility compared to white women, but have been underrepresented in prior studies of the association of chlamydia and tubal factor infertility. OBJECTIVES: To estimate the population attributable fraction of tubal factor infertility associated with Chlamydia trachomatis infection by race (black, non-black), and assess how different definitions of C. trachomatis seropositivity and tubal factor infertility affect population attributable fraction estimates. STUDY DESIGN: We conducted a case-control study, enrolling infertile women attending infertility practices in Birmingham, AL and Pittsburgh, PA during October 2012 - June 2015. Tubal factor infertility case status was primarily defined by unilateral or bilateral fallopian tube occlusion (cases) or bilateral fallopian tube patency (controls) on hysterosalpingogram. Alternate tubal factor infertility definitions incorporated history suggestive of tubal damage or were based on laparoscopic evidence of tubal damage. We aimed to enroll all eligible women, with an expected ratio of one and three controls per case for black and non-black women, respectively. We assessed C. trachomatis seropositivity with a commercial assay and a more sensitive research assay; our primary measure of seropositivity was defined as positivity on either assay. We estimated C. trachomatis seropositivity and calculated C. trachomatis-TFI odds ratios and population attributable fraction, stratified by race. RESULTS: We enrolled 107 black women (47 cases, 60 controls) and 620 non-black women (140 cases, 480 controls). C. trachomatis seropositivity by either assay was 81% (95% confidence interval 73%, 89%) among black and 31% (95% confidence interval 28%, 35%) among non-black participants (P<0.001). Using the primary C. trachomatis seropositivity and tubal factor infertility definitions, no significant association was detected between chlamydia and tubal factor infertility among blacks (odds ratio 1.22, 95% confidence interval 0.45, 3.28) or non-blacks (odds ratio 1.41, 95% confidence interval 0.95, 2.09), and the estimated population attributable fraction was 15% (95% confidence interval -97%, 68%) among blacks and 11% (95% confidence interval -3%, 23%) among non-blacks. Use of alternate serologic measures and tubal factor infertility definitions impacted the magnitude of the chlamydia-tubal factor infertility association, and resulted in a significant association among non-blacks. CONCLUSIONS: Low population attributable fraction estimates suggest factors in addition to chlamydia contribute to tubal factor infertility in the study population. However, high background C. trachomatis seropositivity among controls, most striking among black participants, could have obscured an association with tubal factor infertility and resulted in a population attributable fraction that underestimates the true etiologic role of chlamydia. Choice of chlamydia and tubal factor infertility definitions also impacts odds ratio and population attributable fraction estimates.

Chlamydia trachomatis (CT) elementary body (EB) ELISA was used to investigate serum anti-CT IgG1 (long-lived response) and IgG3 (short-lived response indicating more recent infection) from treatment (enrollment) and 6-month follow-up visits in 77 women previously classified as having spontaneous resolution of chlamydia. 71.4% of women were IgG1+IgG3+, consistent with more recent chlamydia resolution. 15.6% were IgG3- at both visits, suggesting absence of recent chlamydia. Using EB ELISA, we demonstrated about one in six women classified as having spontaneous resolution of chlamydia might have been exposed to CT but not infected. Further, we classified their possible infection stage.

INTRODUCTION: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a prevalent cause of skin and soft tissue infections (SSTI), but the association between CA-MRSA colonization and infection remains uncertain. We studied the carriage frequency at several body sites and the diversity of S. aureus strains from patients with and without SSTI. MATERIALS AND METHODS: Case-subjects with a closed skin abscess (i.e., without drainage) and matched control subjects without a skin infection (N=147 each) presenting to 10 U.S. emergency departments were cultured at the nares, throat, rectum, and groin using broth enrichment; wounds were cultured from abscess cases. Methicillin resistance testing and spa typing were performed for all S. aureus isolates. RESULTS: S. aureus was found in 85/147 (57.8%) of abscesses; 49 were MRSA, 36 were MSSA. MRSA colonization was more common among cases (59/147; 40.1%) than controls (27/147; 18.4%) overall (p<0.001), and at each body site; no differences were observed for MSSA. S. aureus-infected subjects were usually (75/85) colonized with the infecting strain; among MRSA-infected subjects this was most common in the groin. The CC8 lineage accounted for most of both infecting and colonizing isolates, although more than 16 distinct strains were identified. Nearly all MRSA infections were inferred as USA300. There was more diversity among colonizing than infecting isolates, and among those isolated from controls versus cases. CONCLUSIONS: CC8 S. aureus is a common colonizer of persons with and without skin infections. Detection of S. aureus colonization, and especially MRSA, may be enhanced by extra-nasal site culture.

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.

BACKGROUND: Management of patients' sex partners is a critical element of sexually transmitted disease (STD) control. Expedited partner therapy (EPT), a practice in which patients deliver medication or a prescription directly to their partners, is one option for partner management. As of 2009, New York State law specifically allows EPT for chlamydial infection. Federally qualified health centers (FQHCs) in New York City (NYC) care for patients at risk for STDs. We describe the policies and practices surrounding EPT and other STD management in NYC FQHCs. METHODS: In 2012, we surveyed medical directors at all NYC FQHC parent entities and clinicians at a sample of their corresponding clinical sites about written policies and actual practices regarding EPT for chlamydial infection and other STD management. RESULTS: Twenty-two entities (22/29; 76%) and 51 sites (51/72; 70%) responded to the survey. More than half of entities have a written policy permitting EPT, and 80% of sites provide EPT. Most entity policies allow EPT for, and most sites provide EPT to, adolescents and adults with both opposite-sex and/or same-sex partners. Most sites use electronic health records and provide EPT by prescriptions, and one third of sites do not provide educational materials with EPT. CONCLUSIONS: Our results indicate widespread EPT provision by NYC FQHCs; however, areas for improvement exist, specifically in following guidelines that recommend providing educational materials with EPT and do not recommend EPT for men with male partners. The use of prescriptions for EPT and electronic health records were identified as potential barriers to EPT provision.

Data on the interaction between methicillin-resistant Staphylococcus aureus (MRSA) colonization and clinical infection are limited. During 2007-2008, we enrolled HIV-infected adults in Atlanta, Georgia, USA, in a prospective cohort study. Nares and groin swab specimens were cultured for S. aureus at enrollment and after 6 and 12 months. MRSA colonization was detected in 13%-15% of HIV-infected participants (n = 600, 98% male) at baseline, 6 months, and 12 months. MRSA colonization was detected in the nares only (41%), groin only (21%), and at both sites (38%). Over a median of 2.1 years of follow-up, 29 MRSA clinical infections occurred in 25 participants. In multivariate analysis, MRSA clinical infection was significantly associated with MRSA colonization of the groin (adjusted risk ratio 4.8) and a history of MRSA infection (adjusted risk ratio 3.1). MRSA prevention strategies that can effectively prevent or eliminate groin colonization are likely necessary to reduce clinical infections in this population.

BACKGROUND: Many assumed high morbidity and mortality would accompany the emergence of MRSA USA300 infections as a cause of healthcare-associated infections (HAIs). We evaluated patients with invasive MRSA infections to assess differences in outcomes between infections caused by USA100 and USA300. METHODS: Population-based data for invasive MRSA infections were used to identify two cohorts: (1) non-dialysis patients with central line-associated bloodstream infections (CLABSI); and (2) patients with community-onset pneumonia (PNEUMO) during 2005-2007 from 6 US metropolitan areas. Medical records of patients with confirmed MRSA USA100 or USA300 were reviewed. Logistic regression and, when appropriate, survival analysis was performed to evaluate mortality, early and late complications, and length of stay. RESULTS: A total of 236 and 100 patients were included in the CLABSI and PNEUMO cohorts, respectively. USA300 was the only independent predictor of early complications for PNEUMO patients (OR=2.6, P=.02). Independent predictors of CLABSI late complications included intensive care unit (ICU) admission before MRSA culture (aOR=2.1, P=.01) and Charlson comorbidity index (aOR=2.6; P=.003), but not strain type. PNEUMO patients were significantly more likely to die if they were older (P=.02), black (P<.001) or infected with USA100 strain (P=.02); while those with CLABSI were more likely to die if they were older (P<.001), had comorbidities (P<.001) or had an ICU admission before MRSA culture (P=.001). CONCLUSIONS: USA300 was associated with early complications in PNEUMO patients. However, it was not associated with mortality for either PNEUMO or CLABSI patients. Concerns regarding higher mortality from HAIs caused by USA300 may not be warranted.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of skin infections. Recent case series describe severe community-acquired pneumonia (CAP) caused by MRSA, but the prevalence and risk factors are unknown. METHODS: We prospectively enrolled adults hospitalized with CAP from 12 university-affiliated emergency departments during the winter-spring of 2006 and 2007. Clinical information and culture results were collected, and factors associated with MRSA were assessed. RESULTS: Of 627 patients, 595 (95%) had respiratory (50%) and/or blood cultures (92%) performed. A pathogen was identified in 102 (17%); MRSA was identified in 14 (2.4%; range by site, 0%-5%) patients and in 5% of patients admitted to the intensive care unit. Two (14%) MRSA pneumonia patients died. All 9 MRSA isolates tested were pulsed-field type USA300. Features significantly associated with isolation of MRSA (as compared with any other or no pathogen) included patient history of MRSA; nursing home admission in the previous year; close contact in the previous month with someone with a skin infection; multiple infiltrates or cavities on chest radiograph; and comatose state, intubation, receipt of pressors, or death in the emergency department. CONCLUSIONS: Methicillin-resistant Staphylococcus aureus remains an uncommon cause of CAP. Detection of MRSA was associated with more severe clinical presentation. (See the Editorial Commentary by Mandell and Wunderink, on pages 1134-6.)

SUMMARY: Travel is a risk factor for Legionnaires' disease. In 2008, two cases were reported in condominium guests where we investigated a 2001 outbreak. We reinvestigated to identify additional cases and determine whether ongoing transmission resulted from persistent colonization of potable water. Exposures were assessed by matched case-control analyses (2001) and case-series interviews (2008). We sampled potable water and other water sources. Isolates were compared using sequence-based typing. From 2001 to 2008, 35 cases were identified. Confirmed cases reported after the cluster in 2001-2002 were initially considered sporadic, but retrospective case-finding identified five additional cases. Cases were more likely than controls to stay in tower 2 of the condominium [matched odds ratio (mOR) 6.1, 95% confidence interval (CI) 1.6-22.9]; transmission was associated with showering duration (mOR 23.0, 95% CI 1.4-384). We characterized a clinical isolate as sequence type 35 (ST35) and detected ST35 in samples of tower 2's potable water in 2001, 2002, and 2008. This prolonged outbreak illustrates the importance of striving for permanent Legionella eradication from potable water.

BACKGROUND: In the past decade, new methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged as a predominant cause of community-associated skin and soft-tissue infections (SSTIs). Little information exists regarding trends in MRSA prevalence and molecular characteristics or regarding antimicrobial susceptibility profiles of S. aureus isolates. METHODS: We enrolled adults with acute, purulent SSTIs presenting to a US network of 12 emergency departments during August 2008. Cultures and clinical information were collected. S. aureus isolates were characterized by antimicrobial susceptibility testing, pulsed-field gel electrophoresis, and toxin genes detection. The prevalence of S. aureus and MRSA and isolate genetic characteristics and susceptibilities were compared with those from a similar study conducted in August 2004. RESULTS: The prevalence of MRSA was 59% among all SSTIs during both study periods; however, the prevalence by site varied less in 2008 (38%-84%), compared with 2004 (15%-74%). Pulsed-field type USA300 continued to account for almost all MRSA isolates (98%). Susceptibility to trimethoprim-sulfamethoxazole, clindamycin, and tetracycline among MRSA isolates remained greater than 90% in 2008. A higher proportion of MRSA infections were treated with an agent to which the infecting isolate was susceptible in vitro in 2008 (97%), compared with 2004 (57%). CONCLUSIONS: Similar to 2004, MRSA remained the most common identifiable cause of purulent SSTIs among patients presenting to a network of US emergency departments in 2008. The infecting MRSA isolates continued to be predominantly pulsed-field type USA300 and susceptible to recommended non-beta-lactam oral agents. Clinician prescribing practices have shifted from MRSA-inactive to MRSA-active empirical antimicrobial regimens.

Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility to vancomycin, and vancomycin treatment failures.

Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility to vancomycin, and vancomycin treatment failures.

Although high rates of clinical infection with methicillin-resistant Staphylococcus aureus (MRSA) have been reported in HIV-infected adults, data on MRSA colonization are limited. We enrolled HIV-infected adults receiving care at the Atlanta VA Medical Center. Swabs from each participant's nares and groin were cultured with broth enrichment for S. aureus. Of 600 HIV-infected adults, 79 (13%) were colonized with MRSA and 180 (30%) with methicillin-susceptible S. aureus. MRSA pulsed-field gel electrophoresis types USA300 (n=44, 54%) and USA500/Iberian (n=29, 35%) predominated. Inclusion of groin swabs increased MRSA detection by 24% and USA300 detection by 38%. In multivariate analysis, MRSA colonization compared to no MRSA colonization was associated with a history of MRSA clinical infection, rarely or never using condoms, and contact with prisons and jails. In summary, the prevalence of MRSA colonization was high in this study of HIV-infected adults and detection of USA300 was enhanced by groin culture.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly being reported to cause outbreaks in neonatal intensive care units (NICUs). We assessed the scope and magnitude of MRSA infections with disease onset after 3 days of age (late-onset MRSA infections) in NICUs. METHODS: We analyzed data reported by NICUs participating in the National Nosocomial Infections Surveillance system from 1995 through 2004. For each surveillance month, all healthcare-associated infections as defined by National Nosocomial Infections Surveillance criteria were reported, along with antimicrobial susceptibility patterns of the isolates. We pooled the data from all NICUs by birth weight category and calendar year. Poisson regression was used to assess changes in incidence of late-onset MRSA infections per 10,000 patient-days. RESULTS: Overall, 149 NICUs reported 4831 S. aureus infections and 5,878,139 patient-days. Methicillin testing data were available for 4302 S. aureus isolates, of which 975 (23%) were MRSA. Incidence of late-onset MRSA infection per 10,000 patient-days, combining all birthweight categories, increased 308% from 0.7 in 1995 to 3.1 in 2004 (P < 0.001). A significant increase in incidence of MRSA infections was observed among all 4 birthweight categories analyzed separately (<or=1000 g, 1001-1500 g, 1501-2500 g, and >2500 g). The distribution of MRSA infection by type of infection did not vary during the study period; 299 (31%) of MRSA infections were bloodstream infections, 174 (18%) were pneumonia, and 161 (17%) were conjunctivitis. CONCLUSION: The incidence of late-onset MRSA infections increased substantially between 1995 and 2004, indicating a need to reinforce infection control recommendations and to explore potential sources and routes of transmission.

With increasing pressure to prevent methicillin-resistant Staphylococcus aureus (MRSA) infection, it is possible that there will be increased use of mupirocin for nasal decolonization of MRSA. Understanding the mechanisms, clinical significance, and epidemiology of mupirocin resistance is important for predicting how changes in mupirocin use may affect bacterial populations and MRSA control. High-level mupirocin resistance in S. aureus is mediated by a plasmid-encoded mupA gene. This gene can be found on conjugative plasmids that carry multiple resistance determinants for other classes of antimicrobial agents. High-level resistance has been associated with decolonization failure, and increased resistance rates have been associated with increased mupirocin use. Low-level mupirocin resistance is mediated via mutation in the native ileS gene, and the clinical significance of this resistance is unclear. Laboratory tests to detect and distinguish between these types of resistance have been described but are not widely available in the United States. Institutions that are considering the implementation of widespread mupirocin use should consider these resistance issues and develop strategies to monitor the impact of mupirocin use.