William Geisler

University of Alabama at Birmingham | UAB · Division of Infectious Diseases

Background Chlamydia trachomatis testing and treatment strategies have not decreased infection rates, justifying need for a chlamydia vaccine. A murine study showed that a vaccine consisting of major outer membrane protein (MOMP) and polymorphic membrane proteins (Pmps) E, F, G, and H elicited protective immunity; studies on human cellular immune r...

Murine research has revealed a significant role for antibody responses in protection against Chlamydia reinfection. To explore potential humoral immune markers of protection elicited by Chlamydia trachomatis (CT) antigens in humans in the context of presumed clinical correlates of protection, we used both an IgG1-based ELISA and a conventional tota...

Introduction Most students in MD-PhD programs take a leave of absence from medical school to complete PhD training, which promotes a natural loss of clinical skills and knowledge and could negatively impact a student’s long-term clinical knowledge. To address this concern, clinical refresher courses in the final year of PhD training have traditiona...

Associations of HLA class II alleles with genital chlamydial infection outcomes have been reported, especially HLA DQB1*06. However, the potential role of DQB1*06 in influencing reinfection risk has still not been established. The purpose of this study was to determine whether the association of DQB1*06 with chlamydia reinfection was impacted by an...

The contribution of chlamydia to secondary infertility in women is poorly understood. Among 404 female participants enrolled in a previous study in Cameroon, 142 with secondary infertility (cases) and 262 pregnant with no history of infertility (controls) , Chlamydia trachomatis seropositivity was 92%. Seropositivity did not significantly differ by...

Background: Mycoplasma genitalium (MG) is on the CDC Watch List of Antimicrobial Resistance Threats yet there is no systematic surveillance to monitor change. Methods: We initiated surveillance in sexual health clinics in six cities, selecting a quota sample of urogenital specimens tested for gonorrhea and/or chlamydia. We abstracted patient dat...

In a prospective study conducted 2020-2021, macrolide resistance-associated mutations (MRMs) were found in 41% of pregnant persons in Birmingham, Alabama with Mycoplasma genitalium (MG) detected. We retrospectively evaluated MG in 203 pregnant persons participating in a study conducted 1997-2001 in Birmingham and adjacent areas and found a prevalen...

Background: Natural clearance of Chlamydia trachomatis (Ct) in women commonly occurs in the interval between screening and treatment. In vitro studies show interferon-gamma (IFN-γ)-mediated tryptophan depletion results in Ct clearance, but whether this mechanism occurs in vivo remains unclear. We previously found that women who naturally cleared C...

Chlamydia trachomatis (CT), caused by various serovars, remains the leading sexually transmitted bacterial infection worldwide. An efficient delivery system is critical to developing whole or subunit vaccines against CT, and some vaccine developmental efforts are targeting biodegradable nanoparticles-based vaccines with encapsulated antigens. We de...

Chlamydia trachomatis infection ("chlamydia") is the most commonly diagnosed bacterial sexually transmitted infection globally, occurring in the genitals (urethra or vagina/cervix), rectum, or pharynx. If left untreated in women, genital chlamydia can ascend into the upper genital tract causing pelvic inflammatory disease, increasing their risk for...

Mycoplasma genitalium is an important sexually transmitted pathogen affecting both men and women. Its extremely slow growth in vitro and very demanding culture requirements necessitate the use of molecular-based diagnostic tests for its detection in clinical specimens. The recent availability of U.S. Food and Drug Administration (FDA)-cleared comme...

Here, we performed in vitro susceptibility testing on 10 Mycoplasma genitalium isolates against omadacycline, minocycline, tetracycline, doxycycline, moxifloxacin, levofloxacin, and azithromycin. Omadacycline was the most potent agent, with all MICs of ≤0.5 μg/mL. MICs were not affected by resistance to other agents, including resistance to other t...

Mycoplasma genitalium was detected in 8% of pregnant women receiving prenatal care, and macrolide resistance gene markers were present in 41% of strains.

To prepare for the development of the 2021 Centers for Disease Control and Prevention (CDC) sexually transmitted infections treatment guidelines, the CDC convened a committee of expert consultants in June 2019 to discuss recent abstracts and published literature on the epidemiology, diagnosis, and management of sexually transmitted infections.This...

Background/objectives: Physician-scientists have long been in high demand owing to their role as key drivers of biomedical innovation, but their dwindling prevalence in research and medical communities threatens ongoing progress. As the principal avenue for physician-scientist development, combined MD-PhD training programs and NIH-funded Medical S...

Among 73 women presenting to a STI clinic in Birmingham, Alabama for reported sexual contact to a chlamydia-infected partner, Chlamydia trachomatis was detected in genital specimens in 24 (32.8%), less often in women reporting prior chlamydial infection (P = 0.001). Most women (93.2%) were C. trachomatis seropositive.

Objective Data on the prevalence and etiology of infertility in Africa are limited. Secondary infertility is particularly common, defined as the inability of a woman to conceive for at least one year following a full-term pregnancy. We describe a prospective study conducted in Cameroon designed to test the hypothesis of an association between commo...

We adapted a simple hydroxylamine-based indole assay to detect indole from stored vaginal swab specimens from women with and without bacterial vaginosis (BV). Women with BV had significantly higher vaginal indole levels compared to women without BV (6451.5 μM vs. 5632.4 μM; P = 0.01), suggesting that indole-producing bacteria are a component of BV.

Chlamydia trachomatis (CT) causes pelvic inflammatory disease, which may result in tubal factor infertility (TFI) in women. Serologic assays may be used to determine the proportion of women with and without TFI who have had previous CT infection and to generate estimates of infertility attributable to chlamydia. Unfortunately, most existing CT sero...

Background Chlamydia trachomatis (Ct) infection ascending to the upper genital tract can cause infertility. Direct association of genetic variants as contributors is challenging because infertility may not be diagnosed until years after infection. Investigating the intermediate trait of ascension bridges this gap. Methods We identified infertility...

Advancing the understanding of pelvic inflammatory disease (PID) requires access to advanced diagnostic approaches for evaluating reproductive sequelae of sexually transmitted infections (STIs). Current limitations of clinical criteria and advanced imaging technologies for diagnosing reproductive sequelae make diagnosis and surveillance of PID a ch...

Background: In men with nongonococcal urethritis (NGU), clinicians and patients rely on clinical cure to guide the need for additional testing/treatment and when to resume sex, respectively; however, discordant clinical and microbiological cure outcomes do occur. How accurately clinical cure reflects microbiological cure in specific sexually trans...

Mycoplasma genitalium (MG) infection, a sexually transmitted infection (STI), causes cervicitis and may cause reproductive sequelae and adverse pregnancy outcomes. Some MG-infected women report dysuria, a symptom frequently attributed to urinary tract infection (UTI). Given potential MG-associated morbidity and the likelihood that UTI treatment wou...

Background: African Americans have the highest rates of Chlamydia trachomatis (CT) infection in the United States and also high reinfection rates. The primary objective of this study was to develop a Bayesian model to predict the probability of CT reinfection in African American women using immunogenetic data. Methods: We analyzed data from a co...

Background: Nearly 14% of US women report any lifetime infertility which is associated with healthcare costs and psychosocial consequences. Tubal factor infertility (TFI) often occurs as a result of sexually transmitted diseases and subsequent pelvic inflammatory disease. We sought to evaluate for and describe potential racial disparities in TFI a...

Background: Chlamydial infection is associated with tubal factor infertility (TFI); however, assessment of prior chlamydial infection and TFI is imperfect. We previously evaluated a combination of serological assays for association with TFI. We now describe the chlamydial contribution to TFI using a newer Chlamydia trachomatis Pgp3 enhanced serolo...

Background: Chlamydia trachomatis (CT) infection remains highly prevalent and young women are disproportionately affected. Most CT-infected women are asymptomatic and their infection often goes unrecognized and untreated. We hypothesized that testing for active CT infection with molecular diagnostics and obtaining a reported history of CT infectio...

We used the Food and Drug Administration-cleared Aptima Mycoplasma genitalium assay to evaluate for M. genitalium infection among young women without urogenital symptoms presenting to a community-based emergency department in Birmingham, Alabama, between August 2016 to August 2019 for evaluation of nongynecological concerns. M. genitalium was detec...

Class Mollicutes includes organisms in the genera Mycoplasma and Ureaplasma. They are prokaryotes that lack a cell wall and are among the smallest known living organisms both in cellular dimension and genome size. At least 17 different species inhabit the mucosae of the respiratory and urogenital tracts of humans, several of which are pathogenic in...

The class Mollicutes includes organisms in the genera Mycoplasma and Ureaplasma. They are prokaryotes that lack a cell wall, and are among the smallest known living organisms in both cellular dimensions and genome sizes. At least 17 different species inhabit the mucosae of the respiratory and urogenital tracts of humans, several of which are pathog...

Background Chlamydia trachomatis is a common bacterial sexually transmitted infection (STI) that can persist or recur after antibiotic treatment. Universal screening for chlamydia in pregnancy is recommended to prevent adverse birth outcomes. Single dose oral azithromycin has been first line therapy for chlamydia in pregnancy since 2006. Objective...

Background: Antimicrobial resistance in Mycoplasma genitalium (MG), a cause of urethritis, is a growing concern. Yet little is known about the geographic distribution of MG resistance in the U.S. or associated clinical outcomes. We evaluated the frequency of MG among men with urethritis, resistance mutations, and post-treatment symptom persistence...

We evaluated the prevalence of Mycoplasma genitalium coinfection in 302 chlamydia-infected women seen at a sexually transmitted disease clinic in Birmingham, AL. M genitalium coinfection was detected in 22 (7.3%). No participant characteristics predicted coinfection. Among coinfected women, M genitalium was detected again in 6 (28.6%) of 21 women r...

Background Our recent case-control study explored the Chlamydia trachomatis population attributable fraction (PAF) for tubal factor infertility (TFI) using an elementary body enzyme-linked immunosorbent serological assay (EB-ELISA) or a commercially available (Medac) major outer membrane protein ELISA to measure prior chlamydial infection. We exami...

Background African Americans have the highest rates of Chlamydia trachomatis (CT) infection in the U.S., nearly six-fold higher than Caucasians. Even after controlling for sociodemographic factors, African American women have higher CT infection rates, suggesting immunogenetic factors could influence infection risk. The primary objective of this st...

Background Mycoplasma genitalium (MG) is an emerging cause of urethritis. Although an FDA-approved MG diagnostic test is now available in the U.S., syndromic management of urethritis remains widespread. Little is known about the geographic distribution of MG resistance in the U.S. and associated clinical outcomes. We evaluated the frequency of MG a...

A longstanding challenge facing MD-PhD students and other dual-degree medical trainees is the loss of clinical knowledge that occurs during the non-medical phases of training. Academic medical institutions nationwide have developed continued clinical training and exposure to maintain clinical competence; however, quantitative assessment of their us...

OBJECTIVES/SPECIFIC AIMS: Chlamydia trachomatis (CT) infection can lead to reproductive morbidity in women. Animal models suggest that protection against CT is mediated through the cytokine interferon-gamma (IFN-γ), produced by CD4+ T-cells, which clears CT through intracellular tryptophan depletion. In humans, correlates of protection remain to be...

Mycoplasma genitalium (MG) infection is a sexually transmitted infection that causes up to 25% of nongonococcal urethritis (NGU). MG strains carrying genetic markers of antimicrobial resistance that may affect treatment outcomes are increasingly recognized as a public health concern. We present two cases of persistent MG NGU with strains carrying b...

Associations between human leukocyte antigen (HLA) variants and chlamydia-related outcomes have been inconsistent. We previously identified HLA-DQB1*06 as a risk marker for chlamydia reinfection in a cohort of predominately HIV-infected adolescents. As chlamydia reinfection can lead to reproductive complications, validation of this finding in HIV-s...

Chlamydia trachomatis (CT) infections remain highly prevalent. CT reinfection occurs frequently within months after treatment, likely contributing to sustaining the high CT infection prevalence. Sparse studies have suggested CT reinfection is associated with a lower organism load, but it is unclear whether CT load at the time of treatment influence...

Background: Adaptive immune responses that mediate protection against Chlamydia trachomatis (CT) remain poorly defined in humans. Animal chlamydia models have demonstrated that CD4⁺ Th1 cytokine responses mediate protective immunity against reinfection. To better understand protective immunity to CT in humans, we investigated whether select CT-spec...

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....

Background: Mycoplasma genitalium (MG) is a sexually transmitted pathogen associated with inflammatory syndromes in men and women. Macrolides and fluoroquinolones are recommended MG treatments. The frequency of MG strains with macrolide resistance-associated mutations (MRMs) and quinolone resistance-associated mutations (QRMs) is increasing worldw...

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...

Chlamydia trachomatis infection (chlamydia) is the most prevalent sexually transmitted bacterial infection and causes significant reproductive morbidity in women. Little is known about how immunity to chlamydia develops in women, though animal models of chlamydia indicate that T-helper type 1 (Th1) responses are important for chlamydia clearance an...

Mycoplasma genitalium (MG) is a sexually transmitted pathogen for which there is no FDA-approved diagnostic test available in the United States. A modified real-time polymerase chain reaction assay for detecting MG and simultaneously identifying macrolide resistance mutations from clinical specimens was evaluated and proved to be sensitive and accu...

T cell phenotypes involved in the immune response to Chlamydia trachomatis (CT) have not been fully elucidated in humans. We evaluated differences in T cell phenotypes between CT-infected women and CT-seronegative controls and investigated changes in T cell phenotype distributions after CT treatment and their association with reinfection. We found...

Problem: Differences in circulating (peripheral) and mucosal T-cell phenotypes in chlamydia-infected women remain largely unknown. Method of study: Thirteen paired mononuclear cell specimens from blood and cervicovaginal lavages collected from chlamydia-infected women were stained and analyzed using ten-color cell surface flow cytometry for T-ce...

We tested for Mycoplasma genitalium in 157 HIV-infected men in Alabama who were mostly asymptomatic. Urogenital and rectal prevalence were 10.8% and 6.4%, respectively. Macrolide resistance mutations were detected in 70.6% and 80% of urogenital and rectal samples and fluoroquinolone resistance mutations in 26.7% and 40% of samples, respectively.

Introduction Mycoplasma genitalium (MG) is a common cause of urethritis in men. In the U.S., CDC recommends treatment for MG with azithromycin or moxifloxacin, but treatment success is threatened by increasing resistance to both therapies. Rectal MG infection has been described among MSM, but little is known about rectal MG prevalence and frequency...

Introduction Mycoplasma genitalium (MG) is a sexually transmitted microbe associated with urethritis in men and several inflammatory syndromes in women. Macrolides and fluoroquinolones have been recommended treatments for MG infections. However, resistance of both drug classes is increasing worldwide and treatment failures have been described. Ther...

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 chlam...

Chlamydia trachomatis (Ct) infection causes significant morbidity. In vitro studies demonstrate Ct growth inhibition occurs by interferon-gamma (IFN-γ)-mediated depletion of intracellular tryptophan, and some Ct strains utilize extracellular indole to restore tryptophan levels. Whether tryptophan levels are associated with Ct infection in clearance...

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+IgG...

Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and can cause significant reproductive morbidity in women. There is insufficient knowledge of C. trachomatis -specific immune responses in humans, which could be important in guiding vaccine development efforts. In contrast, murine models have clearly dem...

The objectives of WHO guidelines are: to provide evidence-based guidance on treatment of infection with C. trachomatis; and to support countries to update their national guidelines for treatment of chlamydial infection.

Background Urogenital Chlamydia trachomatis infection remains prevalent and causes substantial reproductive morbidity. Recent studies have raised concern about the efficacy of azithromycin for the treatment of chlamydia infection. Methods We conducted a randomized trial comparing oral azithromycin with doxycycline for the treatment of urogenital c...

In preparation for the 2015 Centers for Disease Control and Prevention (CDC) Sexually Transmitted Diseases (STD) Treatment Guidelines, the CDC convened an advisory group in 2013 to examine recent abstracts and published literature addressing the epidemiology, diagnosis, and management of STDs. This article summarizes the key questions, evidence, an...

Chlamydia trachomatis (Ct) is the causative agent of the most frequently reported bacterial sexually transmitted infection; the total burden of which is underestimated due to the asymptomatic nature of infection. Untreated Ct infections can cause significant morbidity including pelvic inflammatory disease and tubal factor infertility (TFI). The hum...

Objective: To determine if Chlamydia trachomatis (C. trachomatis) seropositivity, as detected by the C. trachomatis elementary body (EB)-based enzyme-linked immunosorbent assay [EB ELISA] predicts pregnancy and pregnancy outcome among infertile women with documented tubal patency. Design: Cohort study. Setting: Outpatient clinics. Patient(s):...

Little is known about whether Chlamydia trachomatis can be sexually transmitted between women or how often it occurs in women who have sex with women. We investigated Chlamydia trachomatis prevalence and serum Chlamydia trachomatis-specific antibody responses among African American women who have sex with women who reported a lifetime history of se...

Objective: To investigate the association between Chlamydia trachomatis (CT) infection seropositivity and gastroschisis. Study design: In this case-control study we enrolled pregnant women either prenatally diagnosed with gastroschisis (cases, n=33) or with a normal ultrasound (controls, n=66). Both groups attended the University of Utah's Mater...

Background Chlamydia trachomatis (CT) infection remains highly prevalent. CT reinfection occurs in up to 20% of persons within months after treatment, likely contributing to sustaining the high chlamydia prevalence. Most studies evaluating predictors of reinfection have focused on epidemiological and behavioural factors. Our program is studying hos...

Background Urogenital Chlamydia trachomatis infection (“chlamydia”) remains highly prevalent and causes significant reproductive morbidity. Earlier randomised chlamydia treatment trials comparing azithromycin 1g versus a 7-day regimen of doxycycline 100mg twice daily reported high cure rates, but used less sensitive diagnostics and results may have...

Background Chlamydia trachomatis (CT) infection is the most prevalent bacterial sexually transmitted infection worldwide and, untreated, can lead to significant reproductive morbidity. Unfortunately, the prevalence remains high in the United States and no effective CT vaccine exists, in part because of an inadequate knowledge of immunological respo...

Introduction Prevention of tubal factor infertility (TFI) is a primary objective of chlamydia prevention programs. This study aimed to describe TFI epidemiology in infertility clinic patients. Methods Data were analysed from one site of an ongoing two-site study. Medical record data from infertile (unable to conceive for ≥12 months, no history of t...

Repeat Chlamydia trachomatis (CT) detection frequently occurs within months after CT infection treatment. Origins of such infection (persistence vs. reinfection from untreated or new partners) are varied and difficult to determine. CT strains can be differentiated by sequencing the ompA gene, encoding the OmpA protein. We used OmpA genotyping to in...

Background Sexually transmissible infection (STI) history, prevalence and seroprevalence among lifetime exclusive women who have sex with women (WSW) and an age-matched group of women who have sex with women and men (WSWM) was evaluated. Participants completed a study questionnaire and had genital specimens and sera collected for STI testing. Twent...

A human immunodeficiency virus–infected man who has sex with men presented with several months of abdominal pain, diarrhea, rectal pain, and rectal discharge of bright red blood and pus. He reported receptive anal intercourse with multiple casual male partners. He was subsequently diagnosed with lymphogranuloma venereum proctitis and Clostridium di...

In the absence of antiretroviral therapy, valacyclovir may reduce HIV viral load and increase CD4+ T-lymphocyte count. We sought to evaluate the impact of valacyclovir on HIV and HSV-2 in co-infected patients receiving antiretroviral therapy with previously unrecognised HSV-2 infection. A prospective, randomised-controlled, 24-week trial of valacyc...

A randomized, double-blind study comparing single-dose chlamydia therapies of oral rifalazil (25 mg) and azithromycin (1 g) was conducted in 82 women with uncomplicated genital Chlamydia trachomatis infection. The microbiologic cure rate of C. trachomatis with rifalazil (n = 33) was 84.8% at the visit on day 22 to 26 (test-of-cure visit), versus 92...

The clinical presentation of genital Chlamydia trachomatis infection (chlamydia) in women is often indistinguishable from a urinary tract infection. While merited in the setting of dysuria, emergency department (ED) clinicians do not routinely test for chlamydia in women. The primary aim of our study was to evaluate the frequency of chlamydia testi...

Osteitis is an under-recognised clinical manifestation of early syphilis, especially in patients with HIV. We report here a case of syphilitic osteitis of the skull and review its clinical presentation, diagnosis and management.

Background Up to 20% of Chlamydia trachomatis (CT)-infected patients are reinfected within months after treatment, suggesting some fail to develop protective immunity. Genetic determinants influencing CT reinfection risk have not been fully elucidated. Our primary research objective is to identify genetic determinants of CT reinfection. Based on pr...

Background Detection of Chlamydia trachomatis (CT) infection within months of initial diagnosis and treatment is a common occurrence. Origins of such infection (persistence vs. reinfection from an untreated or a new partner) are complex. CT strains can be differentiated by complete nucleotide sequence analysis of the ompA gene, encoding an antigeni...

At the level of the herd (nations), the epidemic of Chlamydia trachomatis genital tract infections has not been controlled despite medical interventions including screening, treatment and partner management programs. However, at the level of the individual it is clear that the host immune response of humans and animals is capable of clearing infect...

Using data from a nationally representative survey, we identified predictors of chlamydial infection in women aged 26 to 39 years. Chlamydia prevalence was low overall but varied by sociodemographics and sexual behaviors. Findings support current recommendations that women older than 25 years should not be routinely screened for chlamydial infectio...

The natural history of chlamydia is variable and may include persisting asymptomatic infection, complications, or spontaneous resolution before treatment. Reinfection is common. We evaluated whether spontaneous resolution was associated with decreased reinfection in women returning for treatment of a positive chlamydia screening test. At enrollment...

Chlamydia trachomatis infection (chlamydia) is the most common notifiable bacterial sexually transmitted infection (STI) worldwide. In the United States of America (USA) in 2009, 1,244,180 cases of chlamydia were reported to the Centers for Disease Control and Prevention (CDC), the largest number of cases ever reported to CDC for any notifiable dis...

Renewed interest in chlamydia vaccination has revealed the need for a greater understanding of the seroprevalence of chlamydial infection in US populations. We used a Chlamydia trachomatis elementary body (EB)–based enzyme-linked immunosorbent assay to define the characteristics of the humoral immune response and to determine seroprevalence. Two gr...

Routine screening for Chlamydia trachomatis and Neisseria gonorrhoeae in men in the United States is not recommended. However, untreated men remain a potential reservoir for chlamydial and gonococcal infections and reinfection among women. Chlamydia and gonorrhea positivities and associated epidemiology were evaluated among males in the southern Un...

Recent studies have raised concern about efficacy of azithromycin for Chlamydia trachomatis infection. Research investigating new antibiotic regimens for chlamydia has been sparse, especially regimens that may reduce adherence difficulties with the recommended twice-daily doxycycline regimen. We conducted a randomized, double-blind, double-dummy, a...

The American Journal of Gastroenterology is published by Nature Publishing Group (NPG) on behalf of the American College of Gastroenterology (ACG). Ranked the #1 clinical journal covering gastroenterology and hepatology*, The American Journal of Gastroenterology (AJG) provides practical and professional support for clinicians dealing with the gastr...

In preparation for the 2015 Centers for Disease Control and Prevention (CDC) Sexually Transmitted Diseases (STD) Treatment Guidelines, the CDC convened an advisory group in 2013 to examine recent abstracts and published literature addressing the epidemiology, diagnosis, and management of STDs. This article summarizes the key questions, evidence, an...

Background Recent studies report that treatment failure rates for single-dose azithromycin for urogenital chlamydia in females may be as high as 8%. There has been sparse research investigating new antibiotics for chlamydia, especially those that may reduce adherence difficulties with the CDC recommended doxycycline regimen (100 mg orally twice dai...