Challenges with gonorrhea in the era of multi-drug and extensively drug resistance - are we on the right track?

Bactericidal activity of esculetin is associated with impaired cell wall synthesis by targeting glutamate racemase of Neisseria gonorrhoeae

Neisseria gonorrhoeae (NG), the causative organism of gonorrhea, has been classified by the World Health Organization as 'Priority' two organism owing to its increased resistance to antibiotics and even failure of recommended dual therapy with ceftriaxone and azithromycin. As a result, the general and reproductive health of infected individuals is severely compromised. The imminent public health catastrophe of antimicrobial-resistant gonococci cannot be understated, as t he of severe complications and sequelae of infection are not only increasing but their treatment has also become more expensive. Tenacious attempts are underway to discover novel drug targets as well as new drugs to fight against NG. Therefore, a considerable number of phytochemicals have been tested for their remedial intercession via targeting bacterial proteins. The MurI gene encodes for an enzyme called glutamate racemase (MurI) that is primarily involved in peptidoglycan (PG) biosynthesis and is specific to the bacterial kingdom and hence can be exploited as a potential drug target for the treatment of bacterial diseases. Accordingly, diverse families of phytochemicals were screened in silico for their binding affinity with N. Gonorrhoeae MurI (NG-MurI) protein. Esculetin, one of the shortlisted compounds, was evaluated for its functional, structural, and anti-bacterial activity. Treatment with esculetin resulted in growth inhibition, cell wall damage, and altered permeability as revealed by fluorescence and electron microscopy. Furthermore, esculetin inhibited the racemization activity of recombinant, purified NG-MurI protein, one of the enzymes required for peptidoglycan biosynthesis. Our results suggest that esculetin could be further explored as a lead compound for developing new drug molecules against multidrug-resistant strains.

Emerging threat of antimicrobial resistance in Neisseria gonorrhoeae: pathogenesis, treatment challenges, and potential for vaccine development

The continuous rise of antimicrobial resistance (AMR) is a serious concern as it endangers the effectiveness of healthcare interventions that rely on antibiotics in the long run. The increasing resistance of Neisseria gonorrhoeae, the bacteria responsible for causing gonorrhea, to commonly used antimicrobial drugs, is a major concern. This has now become a critical global health crisis. In the coming years, there is a risk of a hidden epidemic caused by the emergence of gonococcal AMR. This will worsen the global situation. Infections caused by N. gonorrhoeae were once considered easily treatable. However, over time, they have become increasingly resistant to commonly used therapeutic medications, such as penicillin, ciprofloxacin, and azithromycin. As a result, this pathogen is developing into a true "superbug," which means that ceftriaxone is now the only available option for initial empirical treatment. Effective management strategies are urgently needed to prevent severe consequences, such as infertility and pelvic inflammatory disease, which can result from delayed intervention. This review provides a thorough analysis of the escalating problem of N. gonorrhoeae, including its pathogenesis, current treatment options, the emergence of drug-resistant mechanisms, and the potential for vaccine development. We aim to provide valuable insights for healthcare practitioners, policymakers, and researchers in their efforts to combat N. gonorrhoeae antibiotic resistance by elucidating the multifaceted aspects of this global challenge.

Whole genome analysis and antimicrobial resistance of Neisseria gonorrhoeae isolates from Ghana

Introduction

Gonorrhoea is a major public health concern. With the global emergence and spread of resistance to last-line antibiotic treatment options, gonorrhoea threatens to be untreatable in the future. Therefore, this study performed whole genome characterization of Neisseria gonorrhoeae collected in Ghana to identify lineages of circulating strains as well as their phenotypic and genotypic antimicrobial resistance (AMR) profiles.

Methods

Whole genome sequencing (WGS) was performed on 56 isolates using both the Oxford Nanopore MinION and Illumina MiSeq sequencing platforms. The Comprehensive Antimicrobial Resistance Database (CARD) and PUBMLST.org/neisseria databases were used to catalogue chromosomal and plasmid genes implicated in AMR. The core genome multi-locus sequence typing (cgMLST) approach was used for comparative genomics analysis.

Results and Discussion

In vitro resistance measured by the E-test method revealed 100%, 91.0% and 85.7% resistance to tetracycline, penicillin and ciprofloxacin, respectively. A total of 22 sequence types (STs) were identified by multilocus sequence typing (MLST), with ST-14422 (n = 10), ST-1927 (n = 8) and ST-11210 (n = 7) being the most prevalent. Six novel STs were also identified (ST-15634, 15636-15639 and 15641). All isolates harboured chromosomal AMR determinants that confer resistance to beta-lactam antimicrobials and tetracycline. A single cefixime-resistant strain, that belongs to N. gonorrhoeae multiantigen sequence type (NG-MAST) ST1407, a type associated with widespread cephalosporin resistance was identified. Neisseria gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR), identified 29 unique sequence types, with ST-464 (n = 8) and the novel ST-3366 (n = 8) being the most prevalent. Notably, 20 of the 29 STs were novel, indicative of the unique nature of molecular AMR determinants in the Ghanaian strains. Plasmids were highly prevalent: pTetM and pblaTEM were found in 96% and 92% of isolates, respectively. The TEM-135 allele, which is an amino acid change away from producing a stable extended-spectrum β-lactamase that could result in complete cephalosporin resistance, was identified in 28.5% of the isolates. Using WGS, we characterized N. gonorrhoeae strains from Ghana, giving a snapshot of the current state of gonococcal AMR in the country and highlighting the need for constant genomic surveillance.

Diagnostics of Gonococcal Infection in Ukraine: Current Challenges in Resource-Constrained Settings

OBJECTIVE

This study aimed to evaluate the compliance of laboratory diagnostics of gonorrhoea in Ukraine with the World Health Organization (WHO) laboratory manual.

MATERIALS AND METHODS

A quantitative non-randomised cross-sectional descriptive postal survey was conducted to evaluate the diagnostics of gonorrhoea in sexually transmitted infections (STI) clinics in Ukraine.

RESULTS

The survey provided data about diagnostics of Neisseria gonorrhoeae in STI clinics from 14 regions of Ukraine from January 2013 to September 2014. The clinics performed microscopy, culture, and point-ofcare- testing in 100%, 85.7%, and 7.1% of the cases, respectively. None of the respondents had the option of performing nucleic acid amplification tests and antimicrobial susceptibility testing. Two regions reported their participation in the collaborative project by WHO on antimicrobial resistance investigation, as national antimicrobial susceptibility surveillance program had not been established in Ukraine. A "three-site testing" (urogenital, pharyngeal, and rectal specimens) in symptomatic heterosexuals was conducted by 25%, "twosite testing" (urogenital and pharyngeal specimens) was conducted by 41.7%, and "one-site testing" (urogenital specimen) was conducted by 33.3% of the respondents. External quality control of laboratory tests for the detection of N. gonorrhoeae was not performed in 50% of the regions in Ukraine. Non-selective culture media for isolation of N. gonorrhoeae and culture media in tubes instead of the recommended Petri dishes were used in 16.7% and 58.3% of the laboratories, respectively.

CONCLUSION

Increased adherence to evidence-basedWHO and/or nationally adapted management guidelines is essential for monitoring gonorrhoea and preventing antimicrobial resistance of N. gonorrhoeae in Ukraine.

Bacterial sexually transmitted infections

Worldwide, the incidence of bacterial sexually transmitted infections (STIs) has shown a significant increase in recent years. In Germany, this circumstance is reflected by a rise in the number of reported syphilis cases. There has also been an uptick in the incidence of non-notifiable STIs such as gonorrhea and infections caused by Chlamydia trachomatis and Mycoplasma genitalium. A key factor in the spread of these infections is their varied clinical presentation, which includes urogenital, pharyngeal and rectal involvement as well as a large number of asymptomatic cases. New real-time multiplex PCR methods allow for rapid and targeted detection of STI pathogens. The most common bacterial STI is urogenital chlamydial infection caused by serovars D-K, which affects young adults in particular. Lymphogranuloma venereum (LGV) caused by L serovars often presents as chlamydial proctitis. In recent years, Neisseria (N.) gonorrhoeae has shown a significant development of resistance, with high-level monoresistance and multiresistance to antibiotics commonly used for treatment. It is therefore imperative that sensitivity testing of N. gonorrhoeae be performed in addition to nucleic acid amplification tests (NAATs). Increased drug resistance has also been observed for Mycoplasma genitalium, a fact that complicates treatment.

Equations To Predict Antimicrobial MICs in Neisseria gonorrhoeae Using Molecular Antimicrobial Resistance Determinants

The emergence of Neisseria gonorrhoeae strains that are resistant to azithromycin and extended-spectrum cephalosporins represents a public health threat, that of untreatable gonorrhea infections. Multivariate regression modeling was used to determine the contributions of molecular antimicrobial resistance determinants to the overall antimicrobial MICs for ceftriaxone, cefixime, azithromycin, tetracycline, ciprofloxacin, and penicillin. A training data set consisting of 1,280 N. gonorrhoeae strains was used to generate regression equations which were then applied to validation data sets of Canadian (n = 1,095) and international (n = 431) strains. The predicted MICs for extended-spectrum cephalosporins (ceftriaxone and cefixime) were fully explained by 5 amino acid substitutions in PenA, A311V, A501P/T/V, N513Y, A517G, and G543S; the presence of a disrupted mtrR promoter; and the PorB G120 and PonA L421P mutations. The correlation of predicted MICs within one doubling dilution to phenotypically determined MICs of the Canadian validation data set was 95.0% for ceftriaxone, 95.6% for cefixime, 91.4% for azithromycin, 98.2% for tetracycline, 90.4% for ciprofloxacin, and 92.3% for penicillin, with an overall sensitivity of 99.9% and specificity of 97.1%. The correlations of predicted MIC values to the phenotypically determined MICs were similar to those from phenotype MIC-only comparison studies. The ability to acquire detailed antimicrobial resistance information directly from molecular data will facilitate the transition to whole-genome sequencing analysis from phenotypic testing and can fill the surveillance gap in an era of increased reliance on nucleic acid assay testing (NAAT) diagnostics to better monitor the dynamics of N. gonorrhoeae.

Genomic Characterization of Gonococci from Different Anatomic Sites, Italy, 2007-2014

In recent decades, Neisseria gonorrhoeae has developed resistance to several antimicrobial classes. Molecular epidemiology approaches are useful for detecting emerging, often resistant, gonococcal clones. In this study, 67 N. gonorrhoeae isolates from different anatomic sites, collected over 8 years in Italy, were analyzed by whole genome sequencing (WGS). WGS was performed using the Illumina NextSeq 500 platform. Phylogenetic analysis was based on core single nucleotide polymorphism (SNP) and core genome multilocus sequence typing (cgMLST). N. gonorrhoeae multi-antigen sequence typing (NG-MAST), MLST, and N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) were carried out in silico using WGS data. Antimicrobial susceptibility against a four-drug panel was evaluated using a gradient diffusion method. Overall, gonococci clustered in accordance with NG-MAST, MLST, NG-STAR, and antimicrobials susceptibility profiles, but not with the site of isolation, HIV status, and patient sexual orientation. Phylogenetic analysis identified nine clades: two of them were the predominant and including gonococci of G1407 and G2400 genogroups.

Neisseria gonorrhoeae ciprofloxacin-resistant strains were associated with Chlamydia trachomatis coinfection

Aim: This study aims to characterize circulating strains to predict their relationship with sexually transmitted microorganisms, Chlamydia trachomatis, HIV, HCV, Treponema pallidum, HPV, Mycoplasmas, in an Italian multiethnic area, which has revealed a recent increase of Neisseria gonorrhoeae first-line antibiotic resistance. Materials & methods: We performed N. gonorrhoeae multiantigen sequence typing and the N. gonorrhoeae sequence typing for antimicrobial resistance. Results: We identified mutations in genes conferring resistance to cephalosporins, macrolides, fluoroquinolones through por and tbpB loci, and we reported new combinations of already known alleles. N. gonorrhoeae resistance to ciprofloxacin was associated with C. trachomatis coinfection. Conclusion: This study's data proved the utility of a routine N. gonorrhoeae molecular characterization to monitor the evolution of antibiotic resistance and to detect the most effective clinical treatment.

Prevalence of and factors associated with MDR Neisseria gonorrhoeae in England and Wales between 2004 and 2015: analysis of annual cross-sectional surveillance surveys

Objectives

To describe trends in prevalence, susceptibility profile and risk factors for MDR Neisseria gonorrhoeae (MDR-NG) in England and Wales.

Methods

Isolates from 16 242 gonorrhoea episodes at sexual health clinics within the Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP) underwent antimicrobial susceptibility testing. MDR-NG was defined as resistance to ceftriaxone, cefixime or azithromycin, plus at least two of penicillin, ciprofloxacin and spectinomycin. Trends in resistance are presented for 2004-15; prevalence and logistic regression analyses for MDR-NG cover the period of the most recent treatment guideline (ceftriaxone plus azithromycin), 2011-15.

Results

Between 2004 and 2015, the proportion of N. gonorrhoeae isolates fully susceptible to all antimicrobial classes fell from 80% to 46%, with the proportion resistant to multiple (two or more) classes increasing from 7.3% to 17.5%. In 2011-15, 3.5% of isolates were MDR-NG, most of which were resistant to cefixime (100% in 2011, decreasing to 36.9% in 2015) and/or azithromycin (4.2% in 2011, increasing to 84.3% in 2015). After excluding azithromycin-resistant isolates, modal azithromycin MICs were higher in MDR versus non-MDR isolates (0.5 versus 0.125 mg/L), with similar results for ceftriaxone (modal MICs 0.03 versus ≤0.002 mg/L). After adjustment for confounders, MDR-NG was more common among isolates from heterosexual men, although absolute differences in prevalence were small [4.6% versus 3.3% (MSM) and 2.5% (women)].

Conclusions

N. gonorrhoeae is becoming less susceptible to available antimicrobials. Since 2011, a minority of isolates were MDR-NG; however, MICs of azithromycin or ceftriaxone (first-line therapies) for many of these were elevated. These findings highlight the importance of continued antimicrobial stewardship for gonorrhoea.

Self-medication of antibiotics: investigating practice among university students at the Malaysian National Defence University

Background: Self-medication of drugs to alleviate symptoms is a common global behavior, helping relieve burdens on health services, but many drugs eg, antibiotics are prescription-only. Self-medication of antibiotics (SMA) is an irrational use of drugs, contributing to microbial resistance increasing health care costs and higher mortality and morbidity. This study aimed to assess SMA among university students. Methods: This was a cross-sectional study conducted among medical and non-medical students of the National Defence University of Malaysia. A validated instrument was used to gather data. Ethics approval was obtained. Random and universal sampling was adopted, and SPSS 21 was used for data analysis. Results: A total of 649 students participated in the study: 48.5% male and 51.5% female, 39.3% reported self-medicating with antibiotics. Penicillin, doxycycline, clarithromycin were the antibiotics most used with the majority reporting no adverse drug reactions. Cost savings and convenience were the principal reasons for SMA which were mainly obtained from local retail pharmacies. Despite medical students (particularly the more senior) having better knowledge of antibiotic use than non-medical students, 89% of all research participants responded that practicing SMA was a good/acceptable practice. Conclusion: SMA is common amongst Malaysian students and, despite understanding why SMA is unwise, even medical students self-medicate.

Bakterielle sexuell übertragbare Infektionen

Bakterielle sexuell übertragbare Infektionen (STI) zeigen seit Jahren weltweit eine deutliche Zunahme. In Deutschland wird diese Tatsache durch steigende Meldezahlen für Syphilis bestätigt. Auch für die nicht meldepflichtigen STI Gonorrhoe, Chlamydia-trachomatis- und Mycoplasma-genitalium-Infektionen wird eine zunehmende Inzidenz beobachtet. Entscheidend für die Weiterverbreitung ist, dass das breite klinische Spektrum, welches neben Urogenitalsitus auch Pharynx und Rektum einbezieht, durch eine hohe Zahl asymptomatischer Verläufe ergänzt wird. Neue Real-Time-Multiplex-Diagnostikverfahren ermöglichen einen schnellen und gezielten Nachweis von STI-Erregern. Die häufigste bakterielle STI ist die urogenitale Chlamydieninfektion mit den Serovaren D-K, die besonders bei jungen Erwachsenen auftritt. Einer Chlamydien-Proktitis kann eine Infektion mit L-Serovaren und damit eine Lymphogranuloma-venereum (LGV)-Infektion zugrunde liegen. Neisseria (N.) gonorrhoeae zeigte in den letzten Jahren eine starke Resistenzentwicklung mit Ausbildung von Einzel- und Multiresistenzen gegenüber bisher gängigen Antibiotika. Daher ist für N. gonorrhoeae zusätzlich zum nucleic acid amplification test (NAAT) eine kulturelle Empfindlichkeitstestung durchzuführen. Auch für Mycoplasma genitalium sind Resistenzentwicklungen bekannt, die eine Therapie erschweren können.

Aminomethyl Spectinomycins as Therapeutics for Drug-Resistant Gonorrhea and Chlamydia Coinfections

Bacterial sexually transmitted infections are widespread and common, with Neisseria gonorrhoeae (gonorrhea) and Chlamydia trachomatis (chlamydia) being the two most frequent causes. If left untreated, both infections can cause pelvic inflammatory disease, infertility, ectopic pregnancy, and other sequelae. The recommended treatment for gonorrhea is ceftriaxone plus azithromycin (to empirically treat chlamydial coinfections). Antibiotic resistance to all existing therapies has developed in gonorrheal infections. The need for new antibiotics is great, but the pipeline for new drugs is alarmingly small. The aminomethyl spectinomycins, a new class of semisynthetic analogs of the antibiotic spectinomycin, were developed on the basis of a computational analysis of the spectinomycin binding site of the bacterial 30S ribosome and structure-guided synthesis. The compounds display particular potency against common respiratory tract pathogens as well as the sexually transmitted pathogens that cause gonorrhea and chlamydia. Here, we demonstrate the in vitro potencies of several compounds of this class against both bacterial species; the compounds displayed increased potencies against N. gonorrhoeae compared to that of spectinomycin and, significantly, demonstrated activity against C. trachomatis that is not observed with spectinomycin. Efficacies of the compounds were compared to those of spectinomycin and gentamicin in a murine model of infection caused by ceftriaxone/azithromycin-resistant N. gonorrhoeae; the aminomethyl spectinomycins significantly reduced the colonization load and were as potent as the comparator compounds. In summary, data produced by this study support aminomethyl spectinomycins as a promising replacement for spectinomycin and antibiotics such as ceftriaxone for treating drug-resistant gonorrhea, with the added benefit of treating chlamydial coinfections.

Sexually Transmitted Infection Review for the Acute Care Pharmacist

PURPOSE

Review selected sexually transmitted infections (STIs) and treatment recommendations for pharmacists and providers practicing in the acute care setting.

SUMMARY

In 2015, the Centers for Disease Control and Prevention (CDC) published an updated guideline on the treatment of STIs with an emphasis on prevention and new diagnostic strategies to combat the growing problem of STIs in the United States. Despite this guidance, the incidence of infection has continued to grow. In October 2016, an in-depth analysis reported that 20 million new infections occur annually in the United States. With this growing burden of disease, it is pertinent that health-care providers optimize their treatment strategies to improve upon the management of STIs. Focusing on identification of asymptomatic- and symptomatic-infected persons, treatment, education, effective follow-up, and counseling for patients and sexual partners, emergency medicine pharmacists and providers can help minimize the negative long-term health consequences of STIs.

CONCLUSION

In the emergency department setting, clinical pharmacists and providers can play a crucial role in preventing and treating STIs and should continue to expand and keep current their knowledge of this topic.

Neisseria gonorrhoeae Sequence Typing for Antimicrobial Resistance, a Novel Antimicrobial Resistance Multilocus Typing Scheme for Tracking Global Dissemination of N. gonorrhoeae Strains

A curated Web-based user-friendly sequence typing tool based on antimicrobial resistance determinants in Neisseria gonorrhoeae was developed and is publicly accessible (https://ngstar.canada.ca). The N. gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR) molecular typing scheme uses the DNA sequences of 7 genes (penA, mtrR, porB, ponA, gyrA, parC, and 23S rRNA) associated with resistance to β-lactam antimicrobials, macrolides, or fluoroquinolones. NG-STAR uses the entire penA sequence, combining the historical nomenclature for penA types I to XXXVIII with novel nucleotide sequence designations; the full mtrR sequence and a portion of its promoter region; portions of ponA, porB, gyrA, and parC; and 23S rRNA sequences. NG-STAR grouped 768 isolates into 139 sequence types (STs) (n = 660) consisting of 29 clonal complexes (CCs) having a maximum of a single-locus variation, and 76 NG-STAR STs (n = 109) were identified as unrelated singletons. NG-STAR had a high Simpson's diversity index value of 96.5% (95% confidence interval [CI] = 0.959 to 0.969). The most common STs were NG-STAR ST-90 (n = 100; 13.0%), ST-42 and ST-91 (n = 45; 5.9%), ST-64 (n = 44; 5.72%), and ST-139 (n = 42; 5.5%). Decreased susceptibility to azithromycin was associated with NG-STAR ST-58, ST-61, ST-64, ST-79, ST-91, and ST-139 (n = 156; 92.3%); decreased susceptibility to cephalosporins was associated with NG-STAR ST-90, ST-91, and ST-97 (n = 162; 94.2%); and ciprofloxacin resistance was associated with NG-STAR ST-26, ST-90, ST-91, ST-97, ST-150, and ST-158 (n = 196; 98.0%). All isolates of NG-STAR ST-42, ST-43, ST-63, ST-81, and ST-160 (n = 106) were susceptible to all four antimicrobials. The standardization of nomenclature associated with antimicrobial resistance determinants through an internationally available database will facilitate the monitoring of the global dissemination of antimicrobial-resistant N. gonorrhoeae strains.

The frequency of gonorrheal and chlamydial infections in Zanjanian women in 2013-2014

BACKGROUND

Chlamydia trachomatis and Neisseria gonorrhoeae are the most prevalent bacterial sexually transmitted diseases in women.

OBJECTIVE

The purpose of this study was to investigate the prevalence of gonorrheal and chlamydial infections and determination of related risk factors in married women with vaginal discharge attending gynecological outpatient department (OPD) in Zanjan in 2013-2014.

MATERIALS AND METHODS

In this cross sectional study, 100 married women aged 18-49 years with vaginal discharge were evaluated for signs and symptoms of gonococcal and chlamydial infections. Then cervical discharge samples and blood samples were collected from each subject for the detection of Nisseria gonorrhea and Chlamydia trachomatis by bacterial culture and serological tests, respectively.

RESULTS

The overall prevalence of Chlamydia trachomatis and Nisseriagonorrhoeae were 16% and 4%, respectively. There was no significant relationship between the contraception methods, previous history of vaginal infections, previous history of urinary tract infections, number of coitus per week and self-reported symptoms (itching, burning, abdominal pain) with prevalence of Nisseriagonorrhoeae and Chlamydia trachomatis.

CONCLUSION

According to our results, the prevalence of gonococci infection in Zanjan was remarkable and relatively was higher than other parts of Iran, therefore it is necessary to put emphasis on education and further preventive and therapeutic programs.

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.

Drifting towards ceftriaxone treatment failure in gonorrhoea: risk factor analysis of data from the Gonococcal Resistance to Antimicrobials Surveillance Programme in England and Wales

OBJECTIVES

Treatment of Neisseria gonorrhoeae is threatened by the emergence of antimicrobial resistance. We analysed data from the Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP) in England and Wales to identify groups most at risk of reduced susceptibility to the currently recommended first-line therapy, ceftriaxone.

METHODS

Data from GRASP between 2007 and 2013 on ceftriaxone susceptibility and strain types were analysed. Risk factors associated with isolates exhibiting a ceftriaxone minimum inhibitory concentration (MIC) of ≥0.015 mg/L (CTR ≥0.015 mg/L) were identified using logistic regression.

RESULTS

One third of isolates from men who have sex with men (MSM) (1279/4203) and 9.9% from heterosexuals (458/4626) exhibited CTR ≥0.015 mg/L. Between 2007 and 2013, the modal MIC for isolates remained at 0.004 mg/L for MSM but increased from 0.002 to 0.004 mg/L for heterosexuals. Among MSM, CTR ≥0.015 mg/L was associated with Asian ethnicity (crude OR: 1.42; 95% CI 1.07 to 1.88) and previous gonorrhoea (1.34; 1.16 to 1.54). Among heterosexuals, CTR ≥0.015 mg/L was associated with older age (35+ years: 4.31; 3.34 to 5.55), ≥6 sexual partners (1.58; 1.01 to 2.44) and sex abroad (2.23; 1.71 to 2.91). CTR ≥0.015 mg/L was less likely in isolates from heterosexuals of black Caribbean or African ethnicity (0.29; 0.20 to 0.41, 0.66; 0.43 to 0.99), with a concurrent chlamydial infection (0.25; 0.19 to 0.34) or women (0.57; 0.46 to 0.71). Over 600 isolates (CTR ≥0.015 mg/L) were typed; the majority were in Genogroup 1407, containing sequence type 1407.

CONCLUSIONS

The emergence and spread of gonorrhoea with reduced susceptibility to ceftriaxone seems a realistic prospect, most likely in those involved in 'rapid-transmission' or bridging sexual networks.

Increasing Incidence of High-Level Tetracycline-Resistant Neisseria gonorrhoeae due to Clonal Spread and Foreign Import

PURPOSE

The detection of high-level tetracycline-resistant strains of Neisseria gonorrhoeae (TRNG) can make important epidemiological contributions that are relevant to controlling infections from this pathogen. In this study, we aimed to determine the incidence of TRNG isolates over time and also to investigate the characteristics and genetic epidemiology of these TRNG isolates in Korea.

MATERIALS AND METHODS

The antimicrobial susceptibilities of 601 isolates of N. gonorrhoeae from 2004 to 2011 were tested by standard Clinical and Laboratory Standards Institute methods. To determine the molecular epidemiological relatedness, N. gonorrhoeae multi-antigen sequence typing was performed.

RESULTS

The incidence of TRNG increased from 2% in 2004 to 21% in 2011. The minimum inhibitory concentration distributions of ceftriaxone and susceptibility of ciprofloxacin in TRNG were different from non-TRNG and varied according to the year of isolation. Most of the TRNG isolates collected from 2004 to 2007 exhibited genetic relatedness, with sequence type (ST) 1798 being the most common. From 2008 to 2011, the STs of the isolates became more variable and introduction of genetically unrelated TRNG were noted.

CONCLUSION

The increased incidence of TRNG strains until 2007 appears to be due, at least in part, to clonal spread. However, we propose that the emergence of various STs since 2008 could be associated with foreign import.

The Impact of Restricting Over-the-Counter Sales of Antimicrobial Drugs: Preliminary Analysis of National Data

To describe the nationwide impact of a restrictive law on over-the-counter sales of antimicrobial drugs, implemented in Brazil in November 2010. Approximately 75% of the population receives healthcare from the public health system and receives free-of-charge medication if prescribed. Total sales in private pharmacies as compared with other channels of sales of oral antibiotics were evaluated in this observational study before and after the law (2008-2012). Defined daily dose per 1000 inhabitants per day (DDD/TID) was used as standard unit. In private pharmacies the effect of the restrictive law was statistically significant (P < 0.001) with an estimated decrease in DDD/TID of 1.87 (s.e. =  0.18). In addition, the trend of DDD/TID before the restrictive law was greater than after the intervention (P < 0.001). Before November 2010, the slope for the trend line was estimated as 0.08 (s.e. = 0.01) whereas after the law, the estimated slope was 0.03 (s.e. = 0.01). As for the nonprivate channels, no difference in sales was observed (P = 0.643). The impact in the South and Southeast (more developed) regions was higher than in the North, Northeast, and Mid-West. The state capitals had a 19% decrease, compared with 0.8% increase in the rest of the states. Before the law, the sales of antimicrobial drugs were steadily increasing. From November 2010, with the restrictive law, there was an abrupt drop in sales followed by an increase albeit at a significantly lower rate. The impact was higher in regions with better socio-economic status.

Discovery of Novel DNA Gyrase Inhibiting Spiropyrimidinetriones: Benzisoxazole Fusion with N-Linked Oxazolidinone Substituents Leading to a Clinical Candidate (ETX0914)

A novel class of bacterial type-II topoisomerase inhibitor displaying a spiropyrimidinetrione architecture fused to a benzisoxazole scaffold shows potent activity against Gram-positive and fastidious Gram-negative bacteria. Here, we describe a series of N-linked oxazolidinone substituents on the benzisoxazole that improve upon the antibacterial activity of initially described compounds of the class, show favorable PK properties, and demonstrate efficacy in an in vivo Staphylococcus aureus infection model. Inhibition of the topoisomerases DNA gyrase and topoisomerase IV from both Gram-positive and a Gram-negative organisms was demonstrated. Compounds showed a clean in vitro toxicity profile, including no genotoxicity and no bone marrow toxicity at the highest evaluated concentrations or other issues that have been problematic for some fluoroquinolones. Compound 1u was identified for advancement into human clinical trials for treatment of uncomplicated gonorrhea based on a variety of beneficial attributes including the potent activity and the favorable safety profile.

Responding to the challenge of untreatable gonorrhea: ETX0914, a first-in-class agent with a distinct mechanism-of-action against bacterial Type II topoisomerases

With the diminishing effectiveness of current antibacterial therapies, it is critically important to discover agents that operate by a mechanism that circumvents existing resistance. ETX0914, the first of a new class of antibacterial agent targeted for the treatment of gonorrhea, operates by a novel mode-of-inhibition against bacterial type II topoisomerases. Incorporating an oxazolidinone on the scaffold mitigated toxicological issues often seen with topoisomerase inhibitors. Organisms resistant to other topoisomerase inhibitors were not cross-resistant with ETX0914 nor were spontaneous resistant mutants to ETX0914 cross-resistant with other topoisomerase inhibitor classes, including the widely used fluoroquinolone class. Preclinical evaluation of ETX0914 pharmacokinetics and pharmacodynamics showed distribution into vascular tissues and efficacy in a murine Staphylococcus aureus infection model that served as a surrogate for predicting efficacious exposures for the treatment of Neisseria gonorrhoeae infections. A wide safety margin to the efficacious exposure in toxicological evaluations supported progression to Phase 1. Dosing ETX0914 in human volunteers showed sufficient exposure and minimal adverse effects to expect a highly efficacious anti-gonorrhea therapy.

Gonorrhea and Prostate Cancer Incidence: An Updated Meta-Analysis of 21 Epidemiologic Studies

BACKGROUND

The association between gonorrhea and prostate cancer risk has been investigated widely, but the results remain inconsistent and contradictory. We conducted an updated meta-analysis to obtain a more precise estimate of this association.

MATERIAL AND METHODS

PubMed, EMBASE, and the Cochrane Library were searched for papers up to June 2014 to identify eligible studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the influence of gonorrhea on prostate cancer risk.

RESULTS

Twenty-one observational studies (19 case-control and 2 cohort) were eligible, comprising 9965 prostate cancer patients and 118 765 participants. Pooled results indicated that gonorrhea was significantly associated with increased incidence of prostate cancer (OR 1.31, 95% CI 1.14-1.52). The association between gonorrhea and prostate cancer was stronger in African American males (OR 1.32, 95% CI 1.06-1.65) than in Whites (OR 1.05, 95% CI 0.90-1.21).

CONCLUSIONS

Our findings suggest that gonorrhea is associated with an increased risk of prostate cancer, especially among African American males. These results warrant further well-designed, large-scale cohort studies to draw definitive conclusions.

A novel application of radiomimetic compounds as antibiotic drugs

OBJECTIVE

This study aims to examine the potential of radiomimetic compounds as antimicrobial therapeutics, as the recent advances in radiomimetic targeting as well as rapid increase of multidrug resistant bacteria make these compounds attractive for future development.

METHODS

Representative radiomimetics from each of the three major categories was examined; C-1027 and neocarzinostatin from the protein-chromophore enediyne family; Calicheamicin from the non-protein chromophore enediyne family and Bleomycin and Tallysomycin S10b from the glycopeptide family. The activity of these compounds was examined against 12 distinct bacteria species. Inhibition was determined using disc diffusion assays and a subsequent examination of minimum inhibitory concentration of a representative organism. The onset of action of the compounds was also determined by incubating the organisms with drug in liquid media, before plating, and then determining if growth occurred.

RESULTS

We found that the radiomimetic glycopeptides were more active against Gram-negative species, while the enediynes were more effective against Gram-positive species. The radiomimetics also maintained their rapid onset of action, working as quickly as 5 min.

CONCLUSIONS

Radiomimetic compounds have activity against a wide variety of microorganisms and would support the development of radiomimetic-antibody conjugates as potential antibiotics as an option against severe bacterial infections.

Holistic actions are essential to combat the global public health burden of non-viral sexually transmitted infections: challenges and future perspectives

Sexually transmitted infections (STIs) represent a significant international public health burden. These infections result in substantial morbidity, mortality and economic costs globally, and require more attention and resources internationally. This special focus issue of Expert Review of Anti Infective Therapy invited key opinion leaders to review and discuss the challenges associated with the diagnosis and treatment of non-viral STIs. The issue also elucidates the future perspectives, ways forward and holistic actions imperative to effectively combat these STIs.

Characterization of the novel DNA gyrase inhibitor AZD0914: low resistance potential and lack of cross-resistance in Neisseria gonorrhoeae

The unmet medical need for novel intervention strategies to treat Neisseria gonorrhoeae infections is significant and increasing, as rapidly emerging resistance in this pathogen is threatening to eliminate the currently available treatment options. AZD0914 is a novel bacterial gyrase inhibitor that possesses potent in vitro activities against isolates with high-level resistance to ciprofloxacin and extended-spectrum cephalosporins, and it is currently in clinical development for the treatment of N. gonorrhoeae infections. The propensity to develop resistance against AZD0914 was examined in N. gonorrhoeae and found to be extremely low, a finding supported by similar studies with Staphylococcus aureus. The genetic characterization of both first-step and second-step mutants that exhibited decreased susceptibilities to AZD0914 identified substitutions in the conserved GyrB TOPRIM domain, confirming DNA gyrase as the primary target of AZD0914 and providing differentiation from fluoroquinolones. The analysis of available bacterial gyrase and topoisomerase IV structures, including those bound to fluoroquinolone and nonfluoroquinolone inhibitors, has allowed the rationalization of the lack of cross-resistance that AZD0914 shares with fluoroquinolones. Microbiological susceptibility data also indicate that the topoisomerase inhibition mechanisms are subtly different between N. gonorrhoeae and other bacterial species. Taken together, these data support the progression of AZD0914 as a novel treatment option for the oral treatment of N. gonorrhoeae infections.

Changing antimicrobial resistance profiles among Neisseria gonorrhoeae isolates in Italy, 2003 to 2012

The emergence of Neisseria gonorrhoeae isolates displaying resistance to antimicrobial agents is a major public health concern and a serious issue related to the occurrence of further untreatable gonorrhea infections. A retrospective analysis on 1,430 N. gonorrhoeae isolates, collected from 2003 through 2012, for antimicrobial susceptibility by Etest and molecular characterization by Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST) was carried out in Italy. Azithromycin-resistant gonococci decreased from 14% in 2007 to 2.2% in 2012. Similarly, isolates with high MICs to cefixime (>0.125 mg/liter) decreased from 11% in 2008 to 3.3% in 2012. The ciprofloxacin resistance rate remains quite stable, following an increasing trend up to 64% in 2012. The percentage of penicillinase-producing N. gonorrhoeae (PPNG) significantly declined from 77% in 2003 to 7% in 2012. A total of 81 multidrug-resistant (MDR) gonococci were identified, showing 11 different antimicrobial resistance patterns. These were isolated from men who have sex with men (MSM) and from heterosexual patients. Two sequence types (STs), ST661 and ST1407, were the most common. Genogroup 1407, which included cefixime-, ciprofloxacin-, and azithromycin-resistant isolates, was found. In conclusion, a change in the antimicrobial resistance profiles among gonococci was identified in Italy together with a percentage of MDR isolates.