The effectiveness of gentamicin in the treatment of Neisseria gonorrhoeae: a systematic review

WHO's essential medicines and AWaRe: recommendations on first- and second-choice antibiotics for empiric treatment of clinical infections

The WHO Model List of Essential Medicines (EML) prioritizes medicines that have significant global public health value. The EML can also deliver important messages on appropriate medicine use. Since 2017, in response to the growing challenge of antimicrobial resistance, antibiotics on the EML have been reviewed and categorized into three groups: Access, Watch, and Reserve, leading to a new categorization called AWaRe. These categories were developed taking into account the impact of different antibiotics and classes on antimicrobial resistance and the implications for their appropriate use. The 2023 AWaRe classification provides empirical guidance on 41 essential antibiotics for over 30 clinical infections targeting both the primary health care and hospital facility setting. A further 257 antibiotics not included on the EML have been allocated an AWaRe group for stewardship and monitoring purposes. This article describes the development of AWaRe, focussing on the clinical evidence base that guided the selection of Access, Watch, or Reserve antibiotics as first and second choices for each infection. The overarching objective was to offer a tool for optimizing the quality of global antibiotic prescribing and reduce inappropriate use by encouraging the use of Access antibiotics (or no antibiotics) where appropriate. This clinical evidence evaluation and subsequent EML recommendations are the basis for the AWaRe antibiotic book and related smartphone applications. By providing guidance on antibiotic prioritization, AWaRe aims to facilitate the revision of national lists of essential medicines, update national prescribing guidelines, and supervise antibiotic use. Adherence to AWaRe would extend the effectiveness of current antibiotics while helping countries expand access to these life-saving medicines for the benefit of current and future patients, health professionals, and the environment.

Evaluation of the Antimicrobial Activity of Phytochemicals from Tea and Agarwood Leaf Extracts against Isolated Bacteria from Poultry and Curd

Antibiotic-resistant bacteria are becoming increasingly common, leading to a global health crisis. The effects of abusing antibiotics not only increase pathogenic resistance but also cause various diseases and syndromes. Gut microbiota contains many beneficial roles for health, while antibiotics kill both pathogens and gut microbiota which is considered one of the major side effects of antibiotics. In fact, new antibiotic compounds are needed in this urgent scenario; phytoremediation is the oldest but most effective method, and research on the antibacterial properties of several types of medicinal plants has already been conducted. Tea and agarwood plants are well known for their economic contribution in both beverage and cosmetic production, as well as for their medicinal value. In this study, tea and agarwood leaf extracts were analyzed for their antimicrobial activity against both pathogenic and beneficial bacteria. Fresh tea (Camellia sinensis) leaves were collected in three varieties, namely, BT-6 from Sylhet, BT-7 from Moulvibazar, and BT-8 from Habiganj; also, green tea (nonfermented tea), black tea (fully fermented tea), and agarwood (Aquilaria malaccensis) were collected from Sylhet region of Bangladesh. Unlike commercial antibiotics, which have side effects on probiotics (beneficiary bacteria), leaf extract activities were analyzed to check if they had positive effects on probiotics that can be found in the gastrointestinal tract as well as dairy products. Potential beneficiary bacteria, Lysinibacillus macroides strain SRU-001 (NCBI accession no. MW665108), and pathogenic bacteria, Aeromonas caviae strain YPLS-62 (NCBI accession no. MW666783), were isolated from the small intestine of poultry and curd, respectively. Tea and agarwood leaves (5 g powder/80 mL methanol) with solvents were kept for seven days at room temperature, and extracts were applied for antimicrobial assays by the disc diffusion assay against the isolated bacteria. 50 µL of each leaf extract was examined against 50 µL of each bacterial culture, where gentamicin was a control. After 24 hours of incubation, tea and agarwood leaf extracts showed an 11-15 mm zone of inhibition against pathogenic A. caviae, while only BT-8 showed 7 mm (disc diameter 6 mm) against probiotic L. macroides. However, compared to leaf extracts, gentamicin showed a 27 mm zone of inhibition against both L. macroides strain SRU-001 and A. caviae strain YPLS-62 bacteria. This research clearly indicates that gentamicin kills both pathogenic and beneficiary bacteria, while leaf extracts from tea and agarwood plants contain antimicrobial activity against only pathogenic A. caviae but no effects on probiotic L. macroides. This outcome indicates not only the potential therapeutic values of tea and agarwood leaves as antibiotics over commercial antibiotics but also the chance of having pathogens in curd and potential beneficial bacteria from the poultry small intestine.

Management of Neisseria gonorrhoeae in the United States: Summary of Evidence From the Development of the 2020 Gonorrhea Treatment Recommendations and the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infection Treatment Guidelines

INTRODUCTION

Neisseria gonorrhoeae has developed resistance to all first-line recommended therapies, making gonococcal antimicrobial resistance a major public health concern given limited antibiotic options currently and an even smaller antimicrobial development pipeline. Since the release of the Centers for Disease Control and Prevention (CDC) 2015 STD Treatment Guidelines, azithromycin, part of the 2015 dual-drug treatment regimen, has had a rapid rise in resistance. The 2020 CDC Gonorrhea Treatment Recommendations and the 2021 Sexually Transmitted Infections (STI) Treatment Guidelines were developed weighing the priorities of treating the individual, protecting the population, and preventing antimicrobial resistance.

METHODS

Gonorrhea subject matter experts (SME) generated 8 key questions and conducted a literature review of updated data from 2013 to 2019 on gonorrhea antimicrobial resistance, treatment failures, clinical trials, and other key topics. More than 2200 abstracts were assessed, and 248 clinically relevant articles were thoroughly reviewed. SMEs also evaluated N gonorrhoeae antimicrobial resistance data from the Gonococcal Isolate Surveillance Project (GISP).

EVIDENCE

Although there have been reports of ceftriaxone treatment failures internationally, GISP data suggest that ceftriaxone minimal inhibitory concentrations (MICs) have remained stable in the United States, with < 0.1% exhibiting an "alert value" MIC (> 0.25 mcg/mL). However, GISP documented a rapid rise in the proportion of isolates with an elevated MIC (≥ 2.0 mcg/mL) to azithromycin-nearly 5% in 2018. At the same time, new pharmacokinetic/pharmacodynamic data are available, and there is greater recognition of the need for antimicrobial stewardship.

SUMMARY

The 2021 CDC STI Treatment Guidelines now recommend 500mg ceftriaxone intramuscularly once for the treatment of uncomplicated gonorrhea at all anatomic sites. If coinfection with chlamydia has not been excluded, cotreatment with doxycycline 100mg twice daily for 7 days should be added. Few alternative therapies exist for persons with cephalosporin allergies; there are no recommended alternative therapies for N gonorrhoeae infection of the throat.

Gentamicin Susceptibility in Neisseria gonorrhoeae and Treatment Outcomes for Urogenital Gonorrhea After 25 Years of Sustained Gentamicin Use in Malawi

BACKGROUND

Gentamicin has been used for the treatment of gonorrhea in Malawi since 1993. However, declining clinical cure rates have been suspected. We evaluated current Neisseria gonorrhoeae susceptibility to gentamicin in vitro and clinically.

METHODS

Men with acute urethritis were recruited at the Bwaila District Hospital STI Clinic in Lilongwe, Malawi, between January 2017 and August 2019. All men provided urethral swabs for etiological testing at enrollment and test of cure (TOC), 1 week later, using Gram-stained microscopy and culture. We used Etest to determine minimum inhibitory concentrations (MICs) of gentamicin, azithromycin, cefixime, ceftriaxone, ciprofloxacin, and spectinomycin; disc diffusion for tetracycline susceptibility; and whole-genome sequencing (WGS) to verify/refute treatment failure.

RESULTS

Among 183 N. gonorrhoeae culture-positive men enrolled, 151 (82.5%) had a swab taken for TOC. Of these 151 men, 16 (10.6%) had a positive culture at TOC. One hundred forty-one baseline isolates were tested for gentamicin susceptibility using Etest: 2 (1.4%), MIC = 2 μg/mL; 111 (78.7%), MIC = 4 μg/mL; and 28 (19.9%), MIC = 8 μg/mL. All isolates were susceptible to azithromycin, cefixime, ceftriaxone, and spectinomycin, whereas 63.1% had intermediate susceptibility or resistance to ciprofloxacin. Almost all (96.1%) isolates were resistant to tetracycline. All examined isolates cultured at TOC (n = 13) had gentamicin MICs ≤8 μg/mL. Ten men had pretreatment and posttreatment isolates examined by whole-genome sequencing; 2 (20%) were verified new infections (4119 and 1272 single-nucleotide polymorphisms), whereas 8 (80%) were confirmed treatment failures (0-1 single-nucleotide polymorphism).

CONCLUSIONS

Gentamicin MICs poorly predict gonorrhea treatment outcome with gentamicin, and treatment failures are verified with gonococcal strains with in vitro susceptibility to gentamicin. The first-line treatment of gonorrhea in Malawi should be reassessed.

Pharmacodynamics of Ceftriaxone, Ertapenem, Fosfomycin and Gentamicin in Neisseria gonorrhoeae

Objectives: To assess the in vitro effect of select antimicrobials on the growth of N. gonorrhoeae and its pharmacodynamic parameters. Methods: Time–kill assays were performed on two reference N. gonorrhoeae strains (ceftriaxone-resistant WHO X and ceftriaxone-susceptible WHO F) and one clinical N. gonorrhoeae strain (ceftriaxone-susceptible CS03307). Time–kill curves were constructed for each strain by measuring bacterial growth rates at doubling antimicrobial concentrations of ceftriaxone, ertapenem, fosfomycin and gentamicin. Inputs from these curves were used to estimate minimal bacterial growth rates at high antimicrobial concentrations (ψ_min), maximum bacterial growth rates in the absence of antimicrobials (ψ_max), pharmacodynamic minimum inhibitory concentrations (zMIC), and Hill’s coefficients (κ). Results: Ceftriaxone, ertapenem and fosfomycin showed gradual death overtime at higher antimicrobial concentrations with a relatively high ψ_min, demonstrating time-dependent activity. Compared to WHO F, the ψ_min for WHO X was significantly increased, reflecting decreased killing activity for ceftriaxone, ertapenem and fosfomycin. At high ceftriaxone concentrations, WHO X was still efficiently killed. CS03307 also showed a high ψ_min for ceftriaxone in spite of a low MIC and no difference in ψ_min for fosfomycin in spite of significant MIC and zMIC differences. Gentamicin showed rapid killing for all three strains at high concentrations, demonstrating concentration-dependent activity. Conclusions: Based on time–kill assays, high-dosage ceftriaxone could be used to treat N. gonorrhoeae strains with MIC above breakpoint, with gentamicin as a potential alternative. Whether ertapenem or fosfomycin would be effective to treat strains with a high MIC to ceftriaxone is questionable.

In Vitro Efficacy of Gentamicin Alone and in Combination with Ceftriaxone, Ertapenem, and Azithromycin against Multidrug-Resistant Neisseria gonorrhoeae

This study was conducted to determine the in vitro activities of gentamicin alone and in combination with ceftriaxone, ertapenem, and azithromycin against multidrug-resistant (MDR) Neisseria gonorrhoeae isolates. A total of 407 clinical isolates from Nanjing, China, obtained in 2016 to 2017, had MICs determined for gentamicin using the agar dilution method. MDR status was ascribed to 97 strains that displayed decreased susceptibility or resistance to extended-spectrum cephalosporins (ESCs) (ceftriaxone [MIC, ≥0.125 mg/liter] and cefixime [MIC, ≥0.25 mg/liter]), plus resistance to at least two of the following antimicrobials: penicillin (MIC, ≥2 mg/liter), ciprofloxacin (MIC, ≥1 mg/liter), and azithromycin (MIC, ≥1 mg/liter). MDR strains underwent MIC determinations for antimicrobial combinations using the antimicrobial gradient epsilometer test (Etest). Results that ranged from synergy to antagonism were interpreted using the fractional inhibitory concentration (FICI). All 407 gonococcal isolates were susceptible to gentamicin; MICs ranged from 2 mg/liter to 16 mg/liter. Synergy was demonstrated in 16.5% (16/97), 27.8% (27/97), and 8.2% (8/97) of MDR strains when gentamicin was combined with ceftriaxone (geometric mean [GM] FICI, 0.747), ertapenem (GM FICI, 0.662), and azithromycin (GM FICI, 1.021), respectively. No antimicrobial antagonism was observed with any combination tested against MDR strains; overall, antimicrobial combinations were indifferent. The GM MICs of gentamicin were reduced by 2.63-, 3.80-, and 1.98-fold when tested in combination with ceftriaxone, ertapenem, and azithromycin, respectively. The GM MICs of the three additional antimicrobials individually were reduced by 3-, 2.57-, and 1.98-fold, respectively, when each was tested in combination with gentamicin. Gentamicin alone was effective in vitro against N. gonorrhoeae, including MDR isolates. Combination testing of MDR strains showed lower MICs against gentamicin and each of three antimicrobials (ceftriaxone, ertapenem, and azithromycin) when used in combination. IMPORTANCE Antimicrobial-resistant Neisseria gonorrhoeae is a major global public health concern. New treatment options are urgently needed to successfully treat multidrug-resistant (MDR) Neisseria gonorrhoeae infections. This study showed that gentamicin maintained excellent in vitro susceptibility against clinical gonococcal isolates collected in 2016 and 2017, including MDR isolates. Combinations of gentamicin plus ertapenem, ceftriaxone, and azithromycin produced synergistic effects against certain MDR isolates. No antagonism was observed in any of the antimicrobial combinations, which may prove useful to guide clinical testing of combination therapies.

Metabolomics of extracellular compounds and parasitic enzymes of Beauveria bassiana associated with biological control of whiteflies (Bemisia tabaci)

The Beauveria spp. were isolated from soil and insect cadavers of crop rhizosphere and characterized for parasitic enzyme activity and virulence against whiteflies (Bemisia tabaci). The colony morphology and molecular identification using ITS specific marker were carried out and confirmed entomopathogenic fungi as Beauveria bassiana. The bioefficacy of B. bassiana against whiteflies demonstrated highest corrected mortality and lowest LC₅₀ in isolate B. bassiana JAU2 (SEM morphology) followed by JAU1 on 6th days. Parasitic enzymes chitinase and lipase were determined highest in JAU2 and protease activity examined higher in isolate JAU4 followed by JAU2 isolate on 6th days after inoculation. Comparative extracellular metabolomics carried out from potent (JAU1 and JAU2), moderate (JAU4 and JAU14) and weak (JAU6) B. bassiana isolates in normal suborder dextrose agar with yeast extrect (SDAY) and chitin induced media. Results illustrated that total 105 metabolites identified common for all five B. bassiana isolates differing in virulence. However, the color intensity of the metabolites changes in heat map showing differential concentration of that extracellular compound compared to other isolates. The volcano plot analysis illustrated 58 compounds significanlty diverse between potent JAU1 and JAU2 under two different culture conditions of which 34 compounds recognized up regulated in most potent JAU2 under chitin induced media. Out of 34 metabolites, ten compounds viz., fumaricine, resazurin, N-methyldioctylamine, penaresidun B, tetralin, squamocin B, oligomycin C, pubesenolide, epirbuterol and gentamicin C1a were recognized significantly upregulated in most potent JAU2 and reported for antimicrobial, nematicidal, larvicidalor insecticidal activities. The mass spectra and fragment structure were elucidated under LCMS-QTOF for some novel and unique compounds recognized in most potent B. bassiana JAU2, involved in parasitic activity against whiteflies.

Syndromes Associated with Sexually Transmitted Infections in Lilongwe, Malawi: Burden and Trends, 2006 to 2015

ABSTRACT

Monitoring the burden of and trends in sexually transmitted infection syndromes is useful in informing syndromic management guidelines. Among sexually transmitted infection clinic patients in Lilongwe, Malawi, between 2006 and 2015, genital discharge, lower abdominal pain, and genital ulcer syndromes were common. Prevalence of most syndromes remained stable during the 10-year period.

Protective Effects of Liposomal Curcumin on Oxidative Stress/Antioxidant Imbalance, Metalloproteinases 2 and -9, Histological Changes and Renal Function in Experimental Nephrotoxicity Induced by Gentamicin

BACKGROUND

Our study aimed to assess the efficiency of Curcumin nanoformulation (LCC) on experimental nephrotoxicity induced by Gentamicin in rats.

METHODS

Six groups of seven rats were used: C-(control group) received saline solution i.p. (i.p. = intraperitoneal), G-gentamicin (G, 80 mg/kg body weight (b.w.)), GCC1 and GCC2-with G and CC solution (single dose of 10 mg/kg b.w.-CC1, or 20 mg/kg b.w.-CC2), GLCC1 (10 mg/kg b.w.) and GLCC2 (20 mg/kg b.w.) with G and LCC administration. Oxidative stress parameters (NOx = nitric oxide, MDA = malondialdehyde, TOS = total oxidative stress), antioxidant parameters (CAT = catalase, TAC = total antioxidant capacity), matrix metalloproteinases (MMP-2 and MMP-9), and renal function parameters (creatinine, blood urea nitrogen, and urea) were measured. Kidneys histopathologic examination was made for each group.

RESULTS

Pretreatment with CC and LCC in both doses had significantly alleviating effects on assessed parameters (NOx, MDA, TOS, CAT, TAC, MMP-2, and -9) as compared with the untreated group (p < 0.006). Histopathological aspect and renal function were significantly improved in CC and LCC groups. Liposomal formulation (LCC) showed higher efficiency on all examined parameters compared to CC (p < 0.006).

CONCLUSIONS

Our results demonstrated improving renal function and kidney cytoarchitecture, oxidative stress/antioxidant/balance, and MMPs plasma concentrations with better dose-related efficacity of LCC than CC.

Gentamicin as an alternative to ceftriaxone in the treatment of gonorrhoea: the G-TOG non-inferiority RCT

BACKGROUND

Gonorrhoea is a common sexually transmitted infection that can cause pain and discomfort, affect fertility in women and lead to epididymo-orchitis in men. Current treatment is with ceftriaxone, but there is increasing evidence of antimicrobial resistance reducing its effectiveness. Gentamicin is a potential alternative treatment requiring further evaluation.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of gentamicin as an alternative treatment to ceftriaxone in the treatment of gonorrhoea.

DESIGN

A multicentre, parallel-group, blinded, non-inferiority randomised controlled trial.

SETTING

Fourteen sexual health clinics in England.

PARTICIPANTS

Adults aged 16-70 years with a diagnosis of uncomplicated, untreated genital, pharyngeal or rectal gonorrhoea based on a positive Gram-stained smear on microscopy or a positive nucleic acid amplification test (NAAT).

RANDOMISATION AND BLINDING

Participants were randomised using a secure web-based system, stratified by clinic. Participants, investigators and research staff assessing participants were blinded to treatment allocation.

INTERVENTIONS

Allocation was to either 240 mg of gentamicin (intervention) or 500 mg of ceftriaxone (standard treatment), both administered as a single intramuscular injection. All participants also received 1 g of oral azithromycin.

MAIN OUTCOME MEASURE

The primary outcome measure was clearance of Neisseria gonorrhoeae at all infected sites, confirmed by a negative Aptima Combo 2® (Hologic Inc., Marlborough, MA, USA) NAAT, at 2 weeks post treatment.

RESULTS

We randomised 720 participants, of whom 81% were men. There were 358 participants in the gentamicin group and 362 in the ceftriaxone group; 292 (82%) and 306 (85%) participants, respectively, were included in the primary analysis. Non-inferiority of gentamicin to ceftriaxone could not be demonstrated [adjusted risk difference for microbiological clearance -6.4%, 95% confidence interval (CI) -10.4% to -2.4%]. Clearance of genital infection was similar in the two groups, at 94% in the gentamicin group and 98% in the ceftriaxone group, but clearance of pharyngeal infection and rectal infection was lower in the gentamicin group (80% vs. 96% and 90% vs. 98%, respectively). Reported pain at the injection site was higher for gentamicin than for ceftriaxone. The side-effect profiles were comparable between the groups. Only one serious adverse event was reported and this was deemed not to be related to the trial medication. The economic analysis found that treatment with gentamicin is not cost neutral compared with standard care, with average patient treatment costs higher for those allocated to gentamicin (£13.90, 95% CI £2.47 to £37.34) than to ceftriaxone (£6.72, 95% CI £1.36 to £17.84).

LIMITATIONS

Loss to follow-up was 17% but was similar in both treatment arms. Twelve per cent of participants had a negative NAAT for gonorrhoea at their baseline visit but this was balanced between treatment groups and unlikely to have biased the trial results.

CONCLUSIONS

The trial was unable to demonstrate non-inferiority of gentamicin compared with ceftriaxone in the clearance of gonorrhoea at all infected sites. Clearance at pharyngeal and rectal sites was lower for participants allocated to gentamicin than for those allocated to ceftriaxone, but was similar for genital sites in both groups. Gentamicin was associated with more severe injection site pain. However, both gentamicin and ceftriaxone appeared to be well tolerated.

FUTURE WORK

Exploration of the genetic determinants of antibiotic resistance in N. gonorrhoeae will help to identify accurate markers of decreased susceptibility. Greater understanding of the immune response to infection can assist gonococcal vaccine development.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN51783227.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 20. See the NIHR Journals Library website for further project information.

The Use of Gentamicin for Treatment of Urogenital and Extragenital Gonorrhea: A Systematic Review of Efficacy Data

OBJECTIVE

To evaluate clinical efficacy data for gentamicin in the treatment of gonorrhea.

DATA SOURCES

A keyword search of PubMed (1966 to April 2020), EMBASE (1947 to April 2020), and International Pharmaceutical Abstracts (1970 to April 2020) was conducted. The electronic search was supplemented with manual screening of references from identified articles and a search of ClinicalTrials.gov to identify ongoing trials.

STUDY SELECTION AND DATA EXTRACTION

Comparator and noncomparator studies reporting microbiological outcomes of treatment with gentamicin for gonorrhea in humans were included. Data extracted included study year, authors, aim, setting, population, dosing protocols, and outcome results. Risk of bias was assessed according to the Cochrane Risk of Bias Assessment Tool.

DATA SYNTHESIS

A total of 407 articles were identified, of which 11 met inclusion criteria. Two studies were randomized controlled trials, and 1 additional randomized noncomparator study was identified. All other studies were nonrandomized and noncomparator in nature. The highest quality evidence suggests that gentamicin is not noninferior to ceftriaxone (both in addition to azithromycin) for treatment of gonorrhea but may achieve cure rates >90%. Conflicting evidence exists regarding the efficacy of gentamicin-based regimens for the specific treatment of extragenital gonorrhea.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Results of this review could affect patient care and clinical practice because they clearly demonstrate the role of gentamicin for the treatment of gonorrhea as a second-line agent. Future research should confirm findings, especially for the role of gentamicin in extragenital infections.

CONCLUSIONS

Gentamicin-based regimens should be reserved for second-line treatment of urogenital and extragenital gonorrhea infections.

The first wide-scale drug repurposing screen using the Prestwick Chemical Library (1200 bioactive molecules) against Neisseria gonorrhoeae identifies high in vitro activity of auranofin and many additional drugs

Treatment options for gonorrhoea are scarce. Drug repurposing of bioactive molecules approved for other conditions might therefore be of value. We developed a method for wide-scale, systematic drug repurposing screen to identify molecules with activity against Neisseria gonorrhoeae and screened the Prestwick Chemical Library (1200 FDA-approved drugs). As a proof-of-concept, we further examined one promising and interesting screening hit (auranofin; antirheumatic agent). Three WHO gonococcal reference strains (WHO F, O, P) were used for the Library screening. The strains were grown in presence of a fixed concentration of the library drugs in 384-well plates for 12 h, and the remaining bacterial respiration, to reflect growth, was then quantitatively measured using optical density (OD) 450 nm and a resazurin assay. The activity of auranofin was further examined using in vitro susceptibility testing (minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)) against genetically diverse antimicrobial-resistant N. gonorrhoeae strains and time-kill assays. Sixty-eight molecules significantly inhibited bacterial growth of WHO F, O and P. Auranofin showed potent in vitro bactericidal activity (in MIC-, MBC- and time-kill assays) against four WHO reference strains. No cross-resistance between auranofin and any antimicrobial currently or previously used for gonorrhoea treatment was found when examining 51 selected antimicrobial-resistant gonococcal strains. In conclusion, this is the first wide-scale systematic screening effort for repurposing drugs for future treatment of gonorrhoea. Additional studies examining mechanism(s) of action, resistance development, in vivo anti-gonococcal activity and pharmacokinetics/pharmacodynamics for gonococcal infections of auranofin and several other significant screening hits would be valuable.

Evaluation of alternative antibiotics for susceptibility of gonococcal isolates from China

The efficacy of the currently recommended first-line treatments for gonococcal infections - ceftriaxone monotherapy or ceftriaxone/azithromycin dual therapy - is waning rapidly, and efficient alternative antimicrobials are needed urgently to ensure that future treatment of gonorrhoea remains available. As such, the aim of this study was to screen alternative clinically approved antimicrobials for in-vitro activity against Neisseria gonorrhoeae. The susceptibility levels of 504 clinical isolates from Zhejiang Province, China to ertapenem, tigecycline, gentamicin, fosfomycin, gemifloxacin, doxycycline and rifampicin were investigated using the agar dilution method. The presence of resistance determinants was identified by polymerase chain reaction and sequencing. The minimum inhibitory concentration inhibiting 90% of growth (MIC₉₀) was 0.06 mg/L for ertapenem, 0.25 mg/L for tigecycline, 16 mg/L for doxycycline, 4 mg/L for gemifloxacin, 16 mg/L for gentamicin, 32 mg/L for fosfomycin and 128 mg/L for rifampicin. All strains appeared to be susceptible to tigecycline (MIC ≤0.5 mg/L), while a poor correlation between tigecycline and tetracycline susceptibility was observed, indicating that tetracycline resistance determinants have little impact on tigecycline susceptibility. For ertapenem, 30 isolates showed an MIC >0.125 mg/L, but the correlation between ertapenem and ceftriaxone susceptibility was low and only two strains showed an MIC >0.125 mg/L for both antibiotics. Therefore, it appeared that most ceftriaxone-resistant isolates were still susceptible to ertapenem. In conclusion, tigecycline and ertapenem showed good activity against N. gonorrhoeae and limited cross-resistance with previously used antibiotics. Therefore, they might be interesting candidates for further evaluation of their suitability as alternative antigonococcal therapies.

Gentamicin 240 mg plus azithromycin 2 g vs. ceftriaxone 500 mg plus azithromycin 2 g for treatment of rectal and pharyngeal gonorrhoea: a randomized controlled trial

OBJECTIVES

The aim was to evaluate the efficacy and tolerability of gentamicin 240 mg plus azithromycin 2 g for treatment of uncomplicated rectal and pharyngeal gonorrhoea compared to ceftriaxone 500 mg plus azithromycin 2 g, the recommended European first-line gonorrhoea treatment.

METHODS

A non-inferiority, open-label, single-centre randomized controlled trial was conducted in Prague, Czech Republic. Patients, 18-75 years of age, diagnosed with uncomplicated rectal or pharyngeal gonorrhoea by nucleic acid amplification test (NAAT) were randomized to treatment with gentamicin 240 mg intramuscularly plus azithromycin 2 g orally or ceftriaxone 500 g intramuscularly plus azithromycin 2 g orally. The primary outcome was negative culture and negative NAAT, i.e. 1 week and 3 weeks, respectively, after treatment.

RESULTS

Both clinical cure and microbiological clearance was achieved by 100% (95% CI 0.95-1.00) of patients in the gentamicin/azithromycin arm (n = 72; 40 rectal, 17 pharyngeal and 15 rectal+pharyngeal infections both localizations) and 100% (95% CI 0.95-1.00) in ceftriaxone/azithromycin arm (n = 71; 38 rectal, 14 pharyngeal and 19 rectal+pharyngeal infections). The absolute difference between the two arms was 0.0% (CI95% -5.1 to 5.1), thus less than the pre-specified margin of 7%. Administration of gentamicin was not more painful than ceftriaxone according to the visual analogue scale (1.8 vs. 3.4; p <0.001). Gastrointestinal adverse events were similar in the ceftriaxone arm (33/71, 46.5%) and the gentamicin arm (29/72, 40.3%), and overall in most (52/62, 83.9%) cases they were mild.

CONCLUSIONS

Gentamicin 240 mg plus azithromycin 2 g is an effective alternative for treatment of extragenital gonorrhoea.

Gentamicin compared with ceftriaxone for the treatment of gonorrhoea (G-ToG): a randomised non-inferiority trial

BACKGROUND

Gonorrhoea is a common sexually transmitted infection for which ceftriaxone is the current first-line treatment, but antimicrobial resistance is emerging. The objective of this study was to assess the effectiveness of gentamicin as an alternative to ceftriaxone (both combined with azithromycin) for treatment of gonorrhoea.

METHODS

G-ToG was a multicentre, parallel-group, pragmatic, randomised, non-inferiority trial comparing treatment with gentamicin to treatment with ceftriaxone for patients with gonorrhoea. The patients, treating physician, and assessing physician were masked to treatment but the treating nurse was not. The trial took place at 14 sexual health clinics in England. Adults aged 16-70 years were eligible for participation if they had a diagnosis of uncomplicated genital, pharyngeal, or rectal gonorrhoea. Participants were randomly assigned to receive a single intramuscular dose of either gentamicin 240 mg (gentamicin group) or ceftriaxone 500 mg (ceftriaxone group). All participants also received a single 1 g dose of oral azithromycin. Randomisation (1:1) was stratified by clinic and performed using a secure web-based system. The primary outcome was clearance of Neisseria gonorrhoeae at all initially infected sites, defined as a negative nucleic acid amplification test 2 weeks post treatment. Primary outcome analyses included only participants who had follow-up data, irrespective of the baseline visit N gonorrhoeae test result. The margin used to establish non-inferiority was a lower confidence limit of 5% for the risk difference. This trial is registered with ISRCTN, number ISRCTN51783227.

FINDINGS

Of 1762 patients assessed, we enrolled 720 participants between Oct 7, 2014, and Nov 14, 2016, and randomly assigned 358 to gentamicin and 362 to ceftriaxone. Primary outcome data were available for 306 (85%) of 362 participants allocated to ceftriaxone and 292 (82%) of 358 participants allocated to gentamicin. At 2 weeks after treatment, infection had cleared for 299 (98%) of 306 participants in the ceftriaxone group compared with 267 (91%) of 292 participants in the gentamicin group (adjusted risk difference -6·4%, 95% CI -10·4% to -2·4%). Of the 328 participants who had a genital infection, 151 (98%) of 154 in the ceftriaxone group and 163 (94%) of 174 in the gentamicin group had clearance at follow-up (adjusted risk difference -4·4%, -8·7 to 0). For participants with a pharyngeal infection, a greater proportion receiving ceftriaxone had clearance at follow-up (108 [96%] in the ceftriaxone group compared with 82 [80%] in the gentamicin group; adjusted risk difference -15·3%, -24·0 to -6·5). Similarly, a greater proportion of participants with rectal infection in the ceftriaxone group had clearance (134 [98%] in the ceftriaxone group compared with 107 [90%] in the gentamicin group; adjusted risk difference -7·8%, -13·6 to -2·0). Thus, we did not find that a single dose of gentamicin 240 mg was non-inferior to a single dose of ceftriaxone 500 mg for the treatment of gonorrhoea, when both drugs were combined with a 1 g dose of oral azithromycin. The side-effect profiles were similar between groups, although severity of pain at the injection site was higher for gentamicin (mean visual analogue pain score 36 of 100 in the gentamicin group vs 21 of 100 in the ceftriaxone group).

INTERPRETATION

Gentamicin is not appropriate as first-line treatment for gonorrhoea but remains potentially useful for patients with isolated genital infection, or for patients who are allergic or intolerant to ceftriaxone, or harbour a ceftriaxone-resistant isolate. Further research is required to identify and test new alternatives to ceftriaxone for the treatment of gonorrhoea.

FUNDING

UK National Institute for Health Research.

In Vitro Synergy Testing of Gentamicin, an Old Drug Suggested as Future Treatment Option for Gonorrhoea, in Combination With Six Other Antimicrobials Against Multidrug-Resistant Neisseria gonorrhoeae Strains

BACKGROUND

Emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Neisseria gonorrhoeae is a serious concern and combination therapy has been recommended to delay the onset of treatment failures. Gentamicin, an old and inexpensive antibiotic, is recommended in combination with azithromycin for treatment failures cases with the first-line regimen as per the latest Centers for Disease Control and Prevention sexually transmitted disease treatment guidelines. However, not much literature is available on in vitro and in vivo efficacy of this combination. Therefore, this study was carried out to evaluate the in vitro synergy of gentamicin in combination with azithromycin and 5 other antimicrobials.

METHODS

In vitro synergy of gentamicin in combination with cefixime, ceftriaxone, spectinomycin, azithromycin, moxifloxacin, and ertapenem was determined by Etest for 75 N. gonorrhoeae strains, of which 65 were MDR and one was XDR. Fractional inhibitory concentration index (FICI) of ≤0.5 and >4.0 denoted synergy and antagonism respectively.

RESULTS

Maximum efficacy of gentamicin was observed in combination with ertapenem (geometric mean FICI, 0.56) followed by cefixime (FICI, 0.87). There was no antagonism for both these combinations. However, antagonism was demonstrated in 5.3%, 8%, 8%, and 10.7% strains when gentamicin was paired with spectinomycin (FICI, 1.34), ceftriaxone (FICI, 1.13), azithromycin (FICI, 1.49), and moxifloxacin (FICI, 1.30), respectively.

CONCLUSIONS

The findings suggest that gentamicin significantly enhances the in vitro therapeutic potency of ertapenem and cefixime which will be potentially effective to control the spread of MDR and XDR N. gonorrhoeae. The study warrants more in vitro studies and clinical trials for gentamicin + azithromycin and other 3 combinations because of considerable antagonism.

Antimicrobial Resistance in Neisseria gonorrhoeae and Treatment of Gonorrhea

Gonorrhea and antimicrobial resistance (AMR) in Neisseria gonorrhoeae are major public health concerns globally. Dual antimicrobial therapy (mainly ceftriaxone 250-500 mg × 1 plus azithromycin 1-2 g × 1) is currently recommended in many countries. These dual therapies have high cure rates, have likely been involved in decreasing the level of cephalosporin resistance internationally, and inhibit the spread of AMR gonococcal strains. However, ceftriaxone-resistant strains are currently spreading internationally, predominately associated with travel to Asia. Furthermore, the first global treatment failure with recommended dual therapy was reported in 2016 and the first isolates with combined ceftriaxone resistance and high-level azithromycin resistance were reported in 2018 in the UK and Australia. New antimicrobials for treatment of gonorrhea are essential and, of the few antimicrobials in clinical development, zoliflodacin particularly appears promising. Holistic actions are imperative. These include an enhanced advocacy; prevention, early diagnosis, contact tracing, treatment, test-of-cure, and additional measures for effective management of anogenital and pharyngeal gonorrhea; antimicrobial stewardship; surveillance of infection, AMR and treatment failures; and intensified research, for example, regarding rapid molecular point-of-care detection of gonococci and AMR, novel AMR determinants, new antimicrobials, and an effective gonococcal vaccine, which is the only sustainable solution for management and control of gonorrhea.

Adverse effects of a single dose of gentamicin in adults: a systematic review

AIMS

To systematically review the frequency and type of adverse events associated with a single dose of intravenous or intramuscular gentamicin in adults, for any indication, in studies where a comparator was available.

METHODS

A review protocol was developed and registered (PROSPERO: CRD42013003229). Studies were eligible for review if they: recruited participants aged ≥16 years; used gentamicin intramuscularly or intravenously as a single one-off dose; compared gentamicin to another medication or placebo; and monitored adverse events. MEDLINE, EMBASE, Cochrane Library, trial registries, conference proceedings and other relevant databases were searched up to November 2016. Risk of bias was assessed on all included studies.

RESULTS

In total, 15 522 records were identified. After removal of duplicates, screening of title/abstracts for relevance and independent selection of full texts by two reviewers, 36 studies were included. Across all the included studies, 24 107 participants received a single one-off dose of gentamicin (doses ranged from 1 mg kg^-1 to 480 mg per dose). Acute kidney injury was described in 2520 participants receiving gentamicin. The large majority of cases were reversible. There were no cases of ototoxicity reported in patients receiving gentamicin. A meta-analysis was not performed due to study heterogeneity.

CONCLUSIONS

A significant number of patients saw a transient rise in creatinine after a single dose of gentamicin at doses up to 480 mg. Persistent renal impairment and other adverse events were relatively rare.

Sexually transmitted infections: challenges ahead

WHO estimated that nearly 1 million people become infected every day with any of four curable sexually transmitted infections (STIs): chlamydia, gonorrhoea, syphilis, and trichomoniasis. Despite their high global incidence, STIs remain a neglected area of research. In this Commission, we have prioritised five areas that represent particular challenges in STI treatment and control. Chlamydia remains the most commonly diagnosed bacterial STI in high-income countries despite widespread testing recommendations, sensitive and specific non-invasive testing techniques, and cheap effective therapy. We discuss the challenges for chlamydia control and evidence to support a shift from the current focus on infection-based screening to improved management of diagnosed cases and of chlamydial morbidity, such as pelvic inflammatory disease. The emergence and spread of antimicrobial resistance in Neisseria gonorrhoeae is globally recognised. We review current and potential future control and treatment strategies, with a focus on novel antimicrobials. Bacterial vaginosis is the most common vaginal disorder in women, but current treatments are associated with frequent recurrence. Recurrence after treatment might relate to evidence that suggests sexual transmission is integral to the pathogenesis of bacterial vaginosis, which has substantial implications for the development of effective management approaches. STIs disproportionately affect low-income and middle-income countries. We review strategies for case management, focusing on point-of-care tests that hold considerable potential for improving STI control. Lastly, STIs in men who have sex with men have increased since the late 1990s. We discuss the contribution of new biomedical HIV prevention strategies and risk compensation. Overall, this Commission aims to enhance the understanding of some of the key challenges facing the field of STIs, and outlines new approaches to improve the clinical management of STIs and public health.

Antimicrobial-resistant sexually transmitted infections: gonorrhoea and Mycoplasma genitalium

The emergence of antimicrobial resistance (AMR) is a major concern worldwide and already compromises treatment effectiveness and control of several bacterial sexually transmitted infections (STIs). Neisseria gonorrhoeae and Mycoplasma genitalium are evolving into so-called superbugs that can become resistant, both in vitro and clinically, to essentially all antimicrobials available for treatment, causing exceedingly difficult-to-treat or untreatable STIs and threatening global public health. Widespread AMR in these bacteria is likely to persist and even worsen in the future, owing to the high number of infections, widespread and uncontrolled use of antimicrobials, limited surveillance of AMR and clinical failures, as well as the extraordinary capacity of these bacteria to develop AMR. This development would not only result in an increased prevalence of N. gonorrhoeae and M. genitalium infections but also in a considerably increasing number of severe complications affecting reproductive health. To combat this threat, clinicians need to be aware of the current guidelines on diagnostic procedures, recommended treatment regimens, as well as therapeutic options for multidrug-resistant bacteria. AMR testing needs to be more frequently performed, inform treatment decisions and elucidate how AMRs compromise treatment effectiveness, guiding research for effective future therapies.

Gentamicin versus ceftriaxone for the treatment of gonorrhoea (G-TOG trial): study protocol for a randomised trial

BACKGROUND

Gonorrhoea is a common sexually transmitted infection which causes genital pain and discomfort; in women it can also lead to pelvic inflammatory disease and infertility, and in men to epididymo-orchitis. Current treatment is with ceftriaxone, but there is increasing evidence of antimicrobial resistance which is reducing its effectiveness against gonorrhoea. A small, but increasing, number of patients have already been found to have highly resistant strains of gonorrhoea which has been associated with clinical failure. This trial aims to determine whether gentamicin is not clinically worse than ceftriaxone in the treatment of gonorrhoea.

METHODS/DESIGN

This is a blinded, two-arm, multicentre, noninferiority randomised trial. Patients are eligible if they are aged 16-70 years with a diagnosis of genital, pharyngeal and/or rectal gonorrhoea. Exclusion criteria are: known concurrent sexually transmitted infection(s) (excluding chlamydia); bacterial vaginosis and/or Trichomonas vaginalis infection; contraindications or an allergy to gentamicin, ceftriaxone, azithromycin or lidocaine; pregnancy or breastfeeding; complicated gonorrhoeal infection; weight under 40 kg; use of ceftriaxone, gentamicin or azithromycin within the preceding 28 days. Randomisation is to receive a single intramuscular injection of either gentamicin or ceftriaxone, all participants receive 1 g oral azithromycin as standard treatment. The estimated sample size is 720 participants (noninferiority limit 5%). The primary outcome is clearance of Neisseria gonorrhoeae at all infected sites by a negative Nucleic Acid Amplification Test, 2 weeks post treatment. Secondary outcomes include clinical resolution of symptoms, frequency of adverse events, tolerability of therapy, relationship between clinical effectiveness and antibiotic minimum inhibitory concentration for N. gonorrhoeae, and cost-effectiveness.

DISCUSSION

The options for future treatment of gonorrhoea are limited. Results from this randomised trial will demonstrate whether gentamicin is not clinically worse than ceftriaxone for the treatment of gonorrhoea. This will inform clinical practice and policy for the treatment of gonorrhoea when current therapy with cephalosporins is no longer effective, or is contraindicated.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number - ISRCTN51783227 , Registered on 18 September 2014. Current protocol version 2.0 17 June 2015.

Gentamicin Susceptibility among a Sample of Multidrug-Resistant Neisseria gonorrhoeae Isolates in India

Antimicrobial susceptibility testing of 258 Neisseria gonorrhoeae isolates by Etest determined that 60.1% were multidrug resistant (MDR), while 5% of the strains had decreased susceptibility to currently recommended extended-spectrum cephalosporins (ESCs). Among these, 84.5% of MDR strains and 76.9% of strains that had decreased susceptibility to ESCs were susceptible to gentamicin. No MDR isolate was resistant to gentamicin. These in vitro results suggest that gentamicin might be an effective treatment option for the MDR strains and in dual therapy for gonorrhea. However, further research regarding the clinical treatment outcomes is essential.

New treatment options for infections caused by increasingly antimicrobial-resistant Neisseria gonorrhoeae

The emergence of high-level resistance to ceftriaxone is giving rise to serious concern about absence of effective treatment options to cure gonococcal infections. Increasing the dosage regimen can be applied to ceftriaxone and azithromycin, but the emergence of high-level resistance has already been reported. Spectinomycin is another active drug but has low efficacy in the treatment of pharyngeal gonorrhoea. Conventional antibiotics could be introduced for gonococcal treatment, but they have some limitations, such as the absence of clinical trials and breakpoint. Combining antibiotics is another promising method to cure patients and to prevent the emergence of resistance. The most important strategy to maintain the efficacy of antibiotics is rapid detection and dissemination control of novel resistant isolate.

Time-kill curve analysis and pharmacodynamic modelling for in vitro evaluation of antimicrobials against Neisseria gonorrhoeae

BACKGROUND

Gonorrhoea is a sexually transmitted infection caused by the Gram-negative bacterium Neisseria gonorrhoeae. Resistance to first-line empirical monotherapy has emerged, so robust methods are needed to evaluate the activity of existing and novel antimicrobials against the bacterium. Pharmacodynamic models describing the relationship between the concentration of antimicrobials and the minimum growth rate of the bacteria provide more detailed information than the MIC only.

RESULTS

In this study, a novel standardised in vitro time-kill curve assay was developed. The assay was validated using five World Health Organization N. gonorrhoeae reference strains and a range of ciprofloxacin concentrations below and above the MIC. Then the activity of nine antimicrobials with different target mechanisms was examined against a highly antimicrobial susceptible clinical strain isolated in 1964. The experimental time-kill curves were analysed and quantified with a previously established pharmacodynamic model. First, the bacterial growth rates at each antimicrobial concentration were estimated with linear regression. Second, we fitted the model to the growth rates, resulting in four parameters that describe the pharmacodynamic properties of each antimicrobial. A gradual decrease of bactericidal effects from ciprofloxacin to spectinomycin and gentamicin was found. The beta-lactams ceftriaxone, cefixime and benzylpenicillin showed bactericidal and time-dependent properties. Chloramphenicol and tetracycline were purely bacteriostatic as they fully inhibited the growth but did not kill the bacteria. We also tested ciprofloxacin resistant strains and found higher pharmacodynamic MICs (zMIC) in the resistant strains and attenuated bactericidal effects at concentrations above the zMIC.

CONCLUSIONS

N. gonorrhoeae time-kill curve experiments analysed with a pharmacodynamic model have potential for in vitro evaluation of new and existing antimicrobials. The pharmacodynamic parameters based on a wide range of concentrations below and above the MIC provide information that could support improving future dosing strategies to treat gonorrhoea.

Antimicrobial Resistance Expressed by Neisseria gonorrhoeae: A Major Global Public Health Problem in the 21st Century

Neisseria gonorrhoeae is a strictly human pathogen that is typically transmitted by sexual contact. The associated disease gonorrhea has plagued humankind for thousands of years, with a current estimated incidence of 78 million cases per year. Advances in antimicrobial discovery in the 1920s and 1930s leading to the discovery of sulfonamides and penicillin begun the era of effective antimicrobial treatment of gonorrhea. Unfortunately, the gonococcus developed decreased susceptibility or even resistance to these initially employed antibiotics, a trend that continued over subsequent decades with each new antibiotic that was brought into clinical practice. As this pattern of resistance has continued into the 21st century, there is now reason for great concern, especially in an era when few new antibiotics have prospects for use as treatment of gonorrhea. Here, we review the history of gonorrhea treatment regimens and gonococcal resistance to antibiotics, the mechanisms of resistance, resistance monitoring schemes that exist in different international settings, global responses to the challenge of resistance, and prospects for future treatment regimens in the 21st century.

Current and future antimicrobial treatment of gonorrhoea - the rapidly evolving Neisseria gonorrhoeae continues to challenge

Neisseria gonorrhoeae has developed antimicrobial resistance (AMR) to all drugs previously and currently recommended for empirical monotherapy of gonorrhoea. In vitro resistance, including high-level, to the last option ceftriaxone and sporadic failures to treat pharyngeal gonorrhoea with ceftriaxone have emerged. In response, empirical dual antimicrobial therapy (ceftriaxone 250–1000 mg plus azithromycin 1–2 g) has been introduced in several particularly high-income regions or countries. These treatment regimens appear currently effective and should be considered in all settings where local quality assured AMR data do not support other therapeutic options. However, the dual antimicrobial regimens, implemented in limited geographic regions, will not entirely prevent resistance emergence and, unfortunately, most likely it is only a matter of when, and not if, treatment failures with also these dual antimicrobial regimens will emerge. Accordingly, novel affordable antimicrobials for monotherapy or at least inclusion in new dual treatment regimens, which might need to be considered for all newly developed antimicrobials, are essential. Several of the recently developed antimicrobials deserve increased attention for potential future treatment of gonorrhoea. In vitro activity studies examining collections of geographically, temporally and genetically diverse gonococcal isolates, including multidrug-resistant strains particularly with resistance to ceftriaxone and azithromycin, are important. Furthermore, understanding of effects and biological fitness of current and emerging (in vitro induced/selected and in vivo emerged) genetic resistance mechanisms for these antimicrobials, prediction of resistance emergence, time-kill curve analysis to evaluate antibacterial activity, appropriate mice experiments, and correlates between genetic and phenotypic laboratory parameters, and clinical treatment outcomes, would also be valuable. Subsequently, appropriately designed, randomized controlled clinical trials evaluating efficacy, ideal dose, toxicity, adverse effects, cost, and pharmacokinetic/pharmacodynamics data for anogenital and, importantly, also pharyngeal gonorrhoea, i.e. because treatment failures initially emerge at this anatomical site. Finally, in the future treatment at first health care visit will ideally be individually-tailored, i.e. by novel rapid phenotypic AMR tests and/or genetic point of care AMR tests, including detection of gonococci, which will improve the management and public health control of gonorrhoea and AMR. Nevertheless, now is certainly the right time to readdress the challenges of developing a gonococcal vaccine.

Antibiotic resistance in prevalent bacterial and protozoan sexually transmitted infections

The emergence of multi-drug resistant sexually transmitted infections (STIs) is causing a treatment crisis across the globe. While cephalosporin-resistant gonorrhea is one of the most pressing issues, extensively antibiotic resistant Chlamydia trachomatis and Mycoplasma hominis are also becoming commonplace. Experts have suggested that the failure of current treatment regimens are "largely inevitable" and have called for entirely new classes of antimicrobial agents. With the exception of several new classes of drugs primarily targeting nosocomial infections, progress has been slow. While pharmaceutical companies continue to introduce new drugs, they are based on decade-old discoveries. While there is disagreement about what constitutes new classes of antibiotics, many experts suggest that the last truly new family of antimicrobials was discovered in 1987. This review summarizes the existing literature on antibiotic resistance in common bacterial and protozoal STIs. It also briefly discusses several of the most promising alternatives to current therapies, and further examines how advances in drug delivery, formulation, concentration, and timing are improving the efficacy of existing treatments. Finally, the paper discusses the current state of pharmaceutical development for multidrug-resistant STI.

Antibiotic resistance in prevalent bacterial and protozoan sexually transmitted infections

The emergence of multi-drug resistant sexually transmitted infections (STIs) is causing a treatment crisis across the globe. While cephalosporin-resistant gonorrhea is one of the most pressing issues, extensively antibiotic resistant Chlamydia trachomatis and Mycoplasma hominis are also becoming commonplace. Experts have suggested that the failure of current treatment regimens are "largely inevitable" and have called for entirely new classes of antimicrobial agents. With the exception of several new classes of drugs primarily targeting nosocomial infections, progress has been slow. While pharmaceutical companies continue to introduce new drugs, they are based on decade-old discoveries. While there is disagreement about what constitutes new classes of antibiotics, many experts suggest that the last truly new family of antimicrobials was discovered in 1987. This review summarizes the existing literature on antibiotic resistance in common bacterial and protozoal STIs. It also briefly discusses several of the most promising alternatives to current therapies, and further examines how advances in drug delivery, formulation, concentration, and timing are improving the efficacy of existing treatments. Finally, the paper discusses the current state of pharmaceutical development for multidrug-resistant STI.