Kevin Pettus

Etiology of Genital Ulcers and Prevalence of Human Immunodeficiency Virus Coinfection in 10 US Cities

To determine the etiology of genital ulcers and to assess the prevalence of human immunodeficiency virus (HIV) infection in ulcer patients in 10 US cities, ulcer and serum specimens were collected from approximately 50 ulcer patients at a sexually transmitted disease clinic in each city. Ulcer specimens were tested using a multiplex polymerase chain reaction assay to detect Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus (HSV); sera were tested for antibody to HIV. H. ducreyi was detected in ulcer specimens from patients in Memphis (20% of specimens) and Chicago (12%). T. pallidum was detected in ulcer specimens from every city except Los Angeles (median, 9% of specimens; range, 0%-46%). HSV was detected in >/=50% of specimens from all cities except Memphis (42%). HIV seroprevalence in ulcer patients was 6% (range by city, 0%-18%). These data suggest that chancroid is prevalent in some US cities and that persons with genital ulcers should be a focus of HIV prevention activities.

Neisseria gonorrhoeae Antimicrobial Susceptibility Surveillance - The Gonococcal Isolate Surveillance Project, 27 Sites, United States, 2014.

PROBLEM/CONDITION Gonorrhea is the second most commonly reported notifiable disease in the United States; 350,062 gonorrhea cases were reported in 2014. Sexually transmitted infections caused by Neisseria gonorrhoeae are a cause of pelvic inflammatory disease in women, which can lead to serious reproductive complications including tubal infertility, ectopic pregnancy, and chronic pelvic pain. Prevention of sequelae and of transmission to sexual partners relies largely on prompt detection and effective antimicrobial treatment. However, treatment has been compromised by the absence of routine antimicrobial susceptibility testing in clinical care and evolution of antimicrobial resistance to the antibiotics used to treat gonorrhea. PERIOD COVERED 2014. DESCRIPTION OF THE SYSTEM The Gonococcal Isolate Surveillance Project (GISP) was established in 1986 as a sentinel surveillance system to monitor trends in antimicrobial susceptibilities of N. gonorrhoeae strains in the United States. Each month, N. gonorrhoeae isolates are collected from up to the first 25 men with gonococcal urethritis attending each of the participating sexually transmitted disease (STD) clinics at 27 sites. The number of participating sites has varied over time (21-30 per year). Selected demographic and clinical data are abstracted from medical records. Isolates are tested for antimicrobial susceptibility using agar dilution at one of five regional laboratories. RESULTS A total of 5,093 isolates were collected in 2014. Of these, 25.3% were resistant to tetracycline, 19.2% to ciprofloxacin, and 16.2% to penicillin (plasmid-based, chromosomal, or both). Reduced azithromycin susceptibility (Azi-RS) (defined as minimum inhibitory concentration [MIC] ≥2.0 µg/mL) increased from 0.6% in 2013 to 2.5% in 2014. The increase occurred in all geographic regions, but was greatest in the Midwest, and among all categories of sex of sex partners (men who have sex with men [MSM], men who have sex with men and women [MSMW], and men who have sex with women [MSW]). No Azi-RS isolates exhibited reduced cefixime or ceftriaxone susceptibility (Cfx-RS and Cro-RS, respectively). The prevalence of Cfx-RS (MIC ≥0.25 µg/mL) increased from 0.1% in 2006 to 1.4% in both 2010 and 2011, decreased to 0.4% in 2013, and increased to 0.8% in 2014. Cro-RS (MIC ≥0.125 µg/mL) increased following a similar pattern but at lesser percentages (increased from 0.1% in 2008 to 0.4% in 2011 and decreased to 0.1% in 2013 and 2014). The percentage of isolates resistant to tetracycline, ciprofloxacin, penicillin, or all three antimicrobials, was greater in isolates from MSM than from MSW. INTERPRETATION This is the first report to present comprehensive surveillance data from GISP and summarize gonococcal susceptibility over time, as well as underscore the history and public health implications of emerging cephalosporin resistance. Antimicrobial susceptibility patterns vary by geographic region within the United States and by sex of sex partner. Because dual therapy with ceftriaxone plus azithromycin is the only recommended gonorrhea treatment, increases in azithromycin and cephalosporin MICs are cause for concern that resistance to these antimicrobial agents might be emerging. It is unclear whether increases in the percentage of isolates with Azi-RS mark the beginning of a trend. The percentage of isolates with elevated cefixime MICs increased during 2009-2010, then decreased during 2012-2013 after treatment recommendations were changed in 2010 to recommend dual therapy (with a cephalosporin and a second antibiotic) and a higher dosage of ceftriaxone. Subsequently, the treatment recommendations were changed again in 2012 to no longer recommend cefixime as part of first-line therapy (leaving ceftriaxone-based dual therapy as the only recommended therapy). Despite the MIC decrease (i.e., trend of improved cefixime susceptibility) during 2012-2013, the increase in the number of strains with Cfx-RS in 2014 underscores the potential threat of cephalosporin-resistant N. gonorrhoeae. PUBLIC HEALTH ACTION The National Strategy for Combating Antibiotic-Resistant Bacteria identifies prevention, rapid detection, and control of outbreaks of ceftriaxone-resistant N. gonorrhoeae infection as a priority for U.S. PUBLIC HEALTH ACTION Antimicrobial susceptibility surveillance is conducted to guide development of treatment recommendations for effective therapy and prevention of complications from and transmission of gonorrhea. Federal agencies can use GISP data to develop national treatment recommendations and set research and prevention priorities. Local and state health departments can use GISP data to determine allocation of STD prevention services and resources, guide prevention planning, and communicate best treatment practices to health care providers. Continued surveillance, appropriate treatment, development of new antibiotics, and prevention of transmission remain the best strategies to reduce gonorrhea incidence and morbidity.

The Efficacy and Safety of Gentamicin Plus Azithromycin and Gemifloxacin Plus Azithromycin as Treatment of Uncomplicated Gonorrhea

BACKGROUND Ceftriaxone is the foundation of currently recommended gonorrhea treatment. There is an urgent need for backup treatment options for patients with cephalosporin allergy or infections due to suspected cephalosporin-resistant Neisseria gonorrhoeae. We evaluated the efficacy and tolerability of 2 combinations of existing noncephalosporin antimicrobials for treatment of patients with urogenital gonorrhea. METHODS We conducted a randomized, multisite, open-label, noncomparative trial in 5 outpatient sexually transmitted disease clinic sites in Alabama, California, Maryland, and Pennsylvania. Patients aged 15-60 years diagnosed with uncomplicated urogenital gonorrhea were randomly assigned to either gentamicin 240 mg intramuscularly plus azithromycin 2 g orally, or gemifloxacin 320 mg orally plus azithromycin 2 g orally. The primary outcome was microbiological cure of urogenital infections (negative follow-up culture) at 10-17 days after treatment among 401 participants in the per protocol population. RESULTS Microbiological cure was achieved by 100% (lower 1-sided exact 95% confidence interval [CI] bound, 98.5%) of 202 evaluable participants receiving gentamicin/azithromycin, and 99.5% (lower 1-sided exact 95% CI bound, 97.6%) of 199 evaluable participants receiving gemifloxacin/azithromycin. Gentamicin/azithromycin cured 10 of 10 pharyngeal infections and 1 of 1 rectal infection; gemifloxacin/azithromycin cured 15 of 15 pharyngeal and 5 of 5 rectal infections. Gastrointestinal adverse events were common in both arms. CONCLUSIONS Gentamicin/azithromycin and gemifloxacin/azithromycin were highly effective for treatment of urogenital gonorrhea. Gastrointestinal adverse events may limit routine use. These non-cephalosporin-based regimens may be useful alternative options for patients who cannot be treated with cephalosporin antimicrobials. Additional treatment options for gonorrhea are needed. Clinical Trials Registration. NCT00926796.

Detection of Neisseria gonorrhoeae Infection by Ligase Chain Reaction Testing of Urine Among Adolescent Women With and Without Chlamydia trachomatis Infection

Background and Objectives: Culture, the conventional method for detection of Neisseria gonorrhoeae, requires invasive sampling and stringent specimen transport conditions. The recently developed ligase chain reaction test (LCR; Abbott Laboratories; North Chicago, IL) allows noninvasive sampling and stable transport conditions, but has not been evaluated with specimens from adolescent populations. Goal of this Study: To perform a comparative evaluation of a commercial LCR test and culture for the diagnosis of N. gonorrhoeae in adolescent women. Study design: Urine and endocervical swab specimens from 330 teenage women seen in two public health adolescent clinics were tested by LCR and culture. For resolution of discordant results, a polymerase chain reaction (PCR) test was developed that directly amplifies N. gonorrhoeae DNA from urine samples processed for LCR. Results: Thirty‐one of 330 (9.4%) cervical specimens were culture‐positive for N. gonorrhoeae, and 30 of 330 (9.1%) urine specimens were positive by LCR. After resolution of 13 discordant results, the sensitivity, specificity, and positive and negative predictive values of LCR for urine were 88.2%, 100%, 100%, 98.7%, respectively, and for culture of endocervical specimens were 82.3%, 98.9%, 90.3% and 98%, respectively. Conclusions: Although more expensive than culture, LCR offers a sensitive means for the detection of N. gonorrhoeae in urine samples and may be useful for this purpose in settings where pelvic examinations are difficult to perform and simultaneous detection of N. gonorrhoeae and Chlamydia trachomatis is advantageous.

Assessment of Etest as an Alternative to Agar Dilution for Antimicrobial Susceptibility Testing of Neisseria gonorrhoeae

ABSTRACT We studied whether the Etest can be used as an alternative to agar dilution to determine antimicrobial susceptibilities of ceftriaxone, cefixime, and cefpodoxime in Neisseria gonorrhoeae surveillance. One hundred fifteen clinical and laboratory isolates of N. gonorrhoeae were tested following the Clinical Laboratory Improvement Amendments (CLIA)-approved CLSI standard agar dilution method and, separately, by the Etest according to the manufacturers recommendations. The MICs were determined and compared. Ten laboratory-generated mutants were used to simulate substantially nonsusceptible specimens. The Etest and agar dilution methods were well correlated. Statistical tests produced regression R 2 values of 88%, 82%, and 85% and Pearson correlation coefficients of 92%, 91%, and 92% for ceftriaxone, cefixime, and cefpodoxime, respectively. When paired comparisons were made, the two tests were 88.7%, 80%, and 87% within 1 log2 dilution from each other for ceftriaxone, cefixime, and cefpodoxime, respectively. The within-2-log2 agreements were 99.1%, 98.3%, and 94.8% for ceftriaxone, cefixime, and cefpodoxime, respectively. Notwithstanding the good correlations and the within-2-log2 general agreement, the Etest results produced slightly lower MICs than the agar dilution results. In conclusion, we found that the Etest can be effectively used as an alternative to agar dilution testing to determine the susceptibility of N. gonorrhoeae to ceftriaxone, cefixime, and cefpodoxime, although we recommend further research into extremely resistant isolates. For isolates within the typical range of clinical MICs, reexamination of the Etest interpretation of susceptible and nonsusceptible categories would likely allow for successful transition from agar dilution to the Etest.

Comparison of Antimicrobial Susceptibilities of Pharyngeal, Rectal, and Urethral Neisseria gonorrhoeae Isolates among Men Who Have Sex with Men

ABSTRACT U.S. surveillance for Neisseria gonorrhoeae antimicrobial susceptibilities is based exclusively on male urethral isolates. These data inform gonorrhea treatment guidelines, including recommendations for the treatment of extragenital infections, but data on the susceptibilities of extragenital isolates are limited. We compared the antimicrobial susceptibilities of pharyngeal, rectal, and urethral gonococcal isolates collected from men who have sex with men (MSM), at five sentinel sites throughout the United States. MICs were determined by the agar dilution method. Generalized linear models were used to compare (i) the proportions of isolates with elevated MICs and (ii) geometric mean MICs according to anatomic site, adjusted for city. In December 2011 to September 2013, totals of 205 pharyngeal, 261 rectal, and 976 urethral isolates were obtained. The proportions of isolates with elevated ceftriaxone MICs (≥0.125 μg/ml) did not differ according to anatomic site (0.5% of pharyngeal isolates, 1.5% of rectal isolates, and 1.7% of urethral isolates, with a city-adjusted odds ratio [aOR] of 0.4 [95% confidence interval {CI}, 0.0 to 3.9] for pharyngeal versus urethral isolates and an aOR of 0.9 [95% CI, 0.2 to 4.2] for rectal versus urethral isolates). The city-adjusted geometric mean ceftriaxone MICs of pharyngeal (0.0153 μg/ml) and rectal (0.0157 μg/ml) isolates did not differ from that of urethral isolates (0.0150 μg/ml) (ratios of geometric mean MICs of 1.02 [95% CI, 0.90 to 1.17] and 1.05 [95% CI, 0.93 to 1.19], respectively). Similar results were observed for other antimicrobials, including cefixime and azithromycin. These findings suggest that, at the population level, gonococcal antimicrobial susceptibility surveillance based on urethral isolates from MSM adequately reflects the susceptibilities of N. gonorrhoeae strains circulating among MSM.

Use of whole-genome sequencing data to analyze 23S rRNA-mediated azithromycin resistance

The whole-genome sequences of 24 isolates of Neisseria gonorrhoeae with elevated minimum inhibitory concentrations (MICs) to azithromycin (≥2.0 µg/mL) were analyzed against a modified sequence derived from the whole-genome sequence of N. gonorrhoeae FA1090 to determine, by signal ratio, the number of mutant copies of the 23S rRNA gene and the copy number effect on 50S ribosome-mediated azithromycin resistance. Isolates that were predicted to contain four mutated copies were accurately identified compared with the results of direct sequencing. Fewer than four mutated copies gave less accurate results but were consistent with elevated MICs.

In vitro assessment of dual drug combinations to inhibit growth of Neisseria gonorrhoeae

ABSTRACT The development of resistance to first-line antimicrobial therapies has led to recommendations for combination therapies for the treatment of gonorrhea infection. Recent studies have shown the success of combination therapies in treating patients, but few have reported on the in vitro activities of these drug combinations. An in vitro assessment of azithromycin in combination with gentamicin demonstrated inhibition of growth and suggests that clinical trials may be warranted to assess the utility of this combination in treating gonorrhea infections.

A Case of Decreased Susceptibility to Ceftriaxone in Neisseria gonorrhoeae in the Absence of a Mosaic Penicillin-Binding Protein 2 (penA) Allele

We report a case of Neisseria gonorrhoeae with a non-mosaic penA allele that exhibited decreased susceptibility to extended-spectrum cephalosporins, including a ceftriaxone minimum inhibitory concentration of 0.5 μg/mL. An analysis of resistance determinants suggested that the observed phenotype might have resulted from the combined effects of mutations in multiple genes.

Comparing the disk-diffusion and agar dilution tests for Neisseria gonorrhoeae antimicrobial susceptibility testing

BackgroundWe assessed the validity of testing for antimicrobial susceptibility of clinical and mutant Neisseria gonorrhoeae (GC) isolates by disk diffusion in comparison to agar dilution, and Etest® (bioMerieux, France), respectively, for three third generation extended spectrum cephalosporins (ESC): ceftriaxone (CRO), cefixime (CFX), and cefpodoxime (CPD).MethodsOne hundred and five clinical isolates and ten laboratory-mutants were tested following Clinical Laboratory Standard Institute (CLSI) and manufacturer’s standards for each of the three methods. The measured diameters by the disk diffusion method were tested for correlation with the MIC values by agar dilution. In addition, comparisons with the Etest® were made. Categorical results for concordance, based on standard CLSI cutoffs, between the disk diffusion and the other two methods, respectively, were tested using the Chi-square statistics. Reproducibility was tested for CFX across a 6-month interval by repeated disk tests.ResultsAcross all 115 specimens, the disk diffusion tests produced good categorical agreements, exhibiting concordance of 93.1%, 92.1%, and 90.4% with agar dilution and 93.0%, 92.1%, and 90.4% with Etest®, for CRO, CFX, and CPD, respectively. Pearson correlations between disk-diffusion diameters and agar dilution MIC’s were -0.59, -0.67, and -0.81 for CRO, CFX, and CPD, respectively. The correlations between disk diffusion and Etest® were -0.58, -0.73, and -0.49. Pearson correlation between the CFX disk readings over a 6-month interval was 91%.ConclusionsDisk diffusion tests remain to be a useful, reliable and fast screening method for qualitative antimicrobial susceptibility testing for ceftriaxone, cefixime, and cefpodoxime.