Multicenter, comparative study of enoxacin and ceftriaxone for treatment of uncomplicated gonorrhea

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.

Treatment efficacy for rectal Neisseria gonorrhoeae: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Rectal gonorrhoea is a common sexually transmitted infection with increasing antimicrobial resistance requiring optimization of available treatments.

OBJECTIVES

This systematic review aimed to assess the efficacy of current treatments, previously trialled treatments and new emerging treatments for rectal Neisseria gonorrhoeae (NG).

METHODS

Online bibliographic databases were search from 1 January 1946 to 14 August 2020. All randomized controlled trials (RCTs) with rectal NG data among participants aged 15 years or above and published in English were included. Random effects meta-analyses were used to estimate overall treatment efficacy, defined as microbiological cure. Sub-group analyses included stratifying by diagnostic assay, by dual versus monotherapy, and by currently recommended treatments (e.g. ceftriaxone ± azithromycin) versus previously trialled but not recommended treatments (e.g. amoxicillin) versus emerging treatments (e.g. zoliflodacin). The study protocol was registered on PROSPERO (CRD42020202998).

RESULTS

54 studies including 1813 participants and 44 treatment regimens were identified. The overall summary treatment efficacy for rectal NG was 100.0% (95% CI: 99.9%-100.0%; I2 = 0.0%; P = 0.86). Efficacy estimates for monotherapies (100.0%; 95% CI: 99.88%-100.0%; I2 = 0.00%; P = 0.97) and dual therapies (100.0%; 95% CI: 97.65%-100.0%; I2 = 56.24%; P = 0.03) were similar. Efficacy was highest for current treatments (100.00%; 95% CI: 99.96%-100.00%; I2 = 0.00%; P = 0.98) versus emerging treatments (97.16%; 95% CI: 86.79%-100.00%; I2 = 0.00%; P = 0.84). There were no trials exclusively investigating rectal NG and small sample size was a limitation in most trials.

CONCLUSIONS

Currently recommended treatments containing ceftriaxone, as mono or dual therapy, are effective. Emerging drugs such as zoliflodacin may be potentially useful for rectal NG but further data are needed.

The use of fluoroquinolones in gonorrhoea: the increasing problem of resistance

The recent re-emergence of gonorrhoea in developed countries has been accompanied by the rise and spread of gonococcal resistance to the fluoroquinolones. In the 1980s fluoroquinolones were considered an important addition to the arsenal of agents used to treat gonorrhoea. They proved to be excellent drugs for this indication, including infections caused by penicillinase-producing and tetracycline-resistant strains of Neisseria gonorrhoeae. However, as gonococci have a well-recognised potential to develop resistance to antibiotics, the first reports of reduced susceptibility to fluoroquinolones appeared a few years after their introduction. Gonococcal resistance to fluoroquinolones is now well-established in the Far East, from where it has spread to Australia, Hawaii, California and Europe. In Africa and Latin America, gonococci continue to be susceptible to fluoroquinolones.

Ceftriaxone: an update of its use in the management of community-acquired and nosocomial infections

Ceftriaxone is a parenteral third-generation cephalosporin with a long elimination half-life which permits once-daily administration. It has good activity against Streptococcus pneumoniae, methicillin-susceptible staphylococci, Haemophilus influenzae, Moraxella catarrhalis and Neisseria spp. Although active against Enterobacteriaceae, the recent spread of derepressed mutants which hyperproduce chromosomal beta-lactamases and extended-spectrum beta-lactamases has diminished the activity of all third-generation cephalosporins against these pathogens necessitating careful attention to sensitivity studies. Extensive data from randomised clinical trials confirm the efficacy of ceftriaxone in serious and difficult-to-treat community-acquired infections including meningitis, pneumonia and nonresponsive acute otitis media. Ceftriaxone also has efficacy in other community-acquired infections including uncomplicated gonorrhoea, acute pyelonephritis and various infections in children. In the nosocomial setting, extensive data also confirm the efficacy of ceftriaxone with or without an aminoglycoside in serious Gram-negative infections, pneumonia, spontaneous bacterial peritonitis and as surgical prophylaxis. Outpatient use of ceftriaxone, either as part of a step-down regimen or parenterally, is a distinguishing feature of the data gathered on the agent over the last decade. The review focuses on new applications of the drug and its use in infections in which the causative pathogens or their resistance patterns have changed over the past decade. Ceftriaxone has a good tolerability profile, the most common events being diarrhoea, nausea, vomiting, candidiasis and rash. Ceftriaxone may cause reversible biliary pseudolithiasis, notably at higher dosages of the drug (>/=2 g/day); however, the incidence of true lithiasis is <0.1%. Injection site discomfort or phlebitis can occur after intramuscular or intravenous administration.

CONCLUSIONS

As a result of its strong activity against S. pneumoniae, ceftriaxone holds an important place, either alone or as part of a combination regimen, in the treatment of invasive pneumococcal infections, including those with reduced beta-lactam susceptibility. Its once-daily administration schedule allows simplification of otherwise complex regimens in a hospital setting and has also contributed to its popularity as a parenteral agent in an ambulatory setting. These properties, together with a well characterised tolerability profile, mean that ceftriaxone is likely to retain its place as an important third-generation cephalosporin in the treatment of serious community-acquired and nosocomial infections.

Reduced clinical efficacy of pazufloxacin against gonorrhea due to high prevalence of quinolone-resistant isolates with the GyrA mutation. The Pazufloxacin STD Group

Forty-two men with gonococcal urethritis were treated with an oral dosage of 200 mg of pazufloxacin, a new fluoroquinolone, three times daily for 3 days. Only 28 of the 42 men (66.7%) had negative culture results for Neisseria gonorrhoeae during follow-up. Of the 42 isolates, 41 could be recultured for antibiotic susceptibility testing and DNA sequencing. In 26 of the 41 isolates (63.4%), GyrA mutations with or without ParC mutations were identified. Among the 26 isolates, 23 contained a single GyrA mutation, 1 contained two GyrA mutations, and 2 contained three mutations including double GyrA and single ParC mutations. A single Ser-91-to-Phe mutation, which was detected in 14 of the 26 isolates, was the most common GyrA mutation, followed by an Ala-75 to Ser mutation and an Asp-95 to Asn or Gly mutation in GyrA. All three isolates with two or three mutations contained the Ser-91-to-Phe GyrA mutation. Eleven of the 14 isolates with the single Ser-91-to-Phe mutation within GyrA and all 3 isolates with two or three mutations persisted after pazufloxacin treatment. On the other hand, all 15 wild-type and 9 mutant isolates with a substitution at codon Ala-75 or Asp-95 were eradicated. The mean MIC of pazufloxacin for mutants with the single Ser-91-to-Phe mutation in GyrA was 66-fold higher than that for the wild type. The results obtained in this study suggest that a high prevalence of fluoroquinolone-resistant gonococcal isolates with the Ser-91-to-Phe mutation in GyrA reduced the efficacy of pazufloxacin as treatment for gonococcal urethritis.

Antibiotic use in the emergency department. IV: Single-dose therapy and parenteral-loading dose therapy

There are a number of infectious diseases that can be treated efficaciously with a single dose of an antimicrobial agent. Other infections that can be treated with oral antibiotics on an outpatient basis may resolve more quickly if a parenteral loading dose is given in the emergency department (ED) prior to discharge. This article reviews the supporting literature and indications for single-dose and parenteral first-dose-loading antimicrobial therapy in the ED. This approach may be appropriate for such diverse infections as streptococcal pharyngotonsillitis, otitis media, urinary tract infections, chlamydial genital infections, vaginitis due to yeast, bacteria, or trichomoniasis, pneumonia, gonorrhea and pelvic inflammatory disease, and pediatric fever without a source.

Enoxacin: a reappraisal of its clinical efficacy in the treatment of genitourinary tract infections

Enoxacin is a 6-fluoronaphthyridinone antibacterial agent with good in vitro activity against Neisseria gonorrhoeae and most Gram-negative urinary tract pathogens. It is less active in vitro against Acinetobacter spp., Pseudomonas aeruginosa, and most Gram-positive bacteria, than against Gram-negative organisms. Enoxacin is rapidly absorbed, with a high oral bioavailability (87 to 91%). Of the absorbed dose, 44 to 56% is excreted unchanged in the urine, with peak urinary concentrations (>500 mg/L within 4 hours) remaining high (>100 mg/L) for up to 24 hours, sufficient to inhibit most urinary tract pathogens. Single (400 mg) and multiple oral dose regimens (100 to 600 mg twice or 3 times daily for 5 to 14 days) of enoxacin are as effective for the treatment of patients with complicated or uncomplicated urinary tract infections as other antibacterial agents such as amoxicillin, cefuroxime axetil, cotrimoxazole (trimethoprim-sulfamethoxazole) or trimethoprim. Noncomparative data suggest that enoxacin is also an effective agent for the treatment of prostatitis. Single 400 mgoral doses of enoxacin produce >/- 95% bacteriological cure rates in gonococcal infections, comparable to those produced by single intramuscular doses of ceftriaxone 250 mg. Perioperative doses of oral enoxacin 200 mg provide effective prophylaxis against postoperative bacteriuria after transurethral resection of the prostate. Concomitant administration of enoxacin with a number of commonly used therapeutic agents (e.g. antacids, methylxanthines, warfarin) affects the pharmacokinetic properties of either enoxacin or the coadministered agents. Enoxacin is reasonably well tolerated, with the incidence of adverse experiences ranging from 0 to 24%. Adverse events are mainly gastrointestinal, neurological or dermatological and resolve with minimal intervention. Overall, although enoxacin exhibits a number of clinical characteristics that are similar to those of other agents for the treatment of genitourinary tract infections, the advantages offered by this agent generally do not outweigh those of alternative fluoroquinolone agents. Thus, it is likely to prove to be yet another addition to the list of agents available for the management of these infections.

Reduced uptake and accumulation of norfloxacin in resistant strains of Neisseria gonorrhoeae isolated in Japan

OBJECTIVE

To investigate the alteration of cell permeability toward fluoroquinolones in Neisseria gonorrhoeae, which is a major quinolone-resistance mechanism along with the alteration of DNA gyrase in gram-negative bacteria. The prevalence of fluoroquinolone-resistant N gonorrhoeae strains is rapidly increasing in Japan.

MATERIALS AND METHODS

The uptake and accumulation of norfloxacin by gonococcal cells, including six clinical and five World Health Organization (WHO) reference strains, were measured. Of the six clinical strains, two were highly resistant to norfloxacin (MIC 8.0 and 4.0 micrograms/ml), two were moderately resistant (MIC 1.0 and 0.5 microgram/ml), and two were sensitive (MIC 0.063 and 0.004 microgram/ml). All five WHO reference strains were sensitive to norfloxacin (MIC < or = 0.001 to 0.063 microgram/ml).

RESULTS

Mean initial norfloxacin uptake in the four resistant strains (104 ng/mg of dry cells) was significantly lower than that in the seven sensitive strains (158 ng/mg of dry cells) (p < 0.05). The mean uptake after 20 minutes was also significantly lower in the four resistant strains (130 ng/mg of dry cells) than in the seven sensitive strains (194 ng/mg of dry cells) (p < 0.05). However, there was no significant difference in mean norfloxacin accumulation after 20 minutes between the four resistant strains (26 ng/mg of dry cells) and the seven sensitive strains (36 ng/mg of dry cells). The accumulation of norfloxacin after 20 minutes was almost zero in two of the four resistant strains, while the remaining two strains accumulated norfloxacin as well as the sensitive strains.

CONCLUSIONS

These findings suggest that alteration of bacterial cell permeability is a quinolone-resistance mechanism in N gonorrhoeae isolated in Japan, and that this bacteria may exhibit other mechanisms such as alteration of DNA gyrase.

In vitro activity of temafloxacin compared with those of other agents against 100 clinical isolates of Neisseria gonorrhoeae

The activity of temafloxacin hydrochloride was evaluated by agar dilution against 100 clinical isolates of Neisseria gonorrhoeae and compared with the activities of penicillin, tetracycline, ceftriaxone, ciprofloxacin, and ofloxacin. Temafloxacin inhibited 100% of study isolates at a concentration of 0.015 microgram/ml or less and was highly active against penicillin- and tetracycline-resistant strains. The in vitro activity of temafloxacin was nearly identical to that of ceftriaxone and was slightly less than that observed with ciprofloxacin and ofloxacin. Temafloxacin represents a promising alternative agent for investigation in the treatment of infection due to N. gonorrhoeae.

Recent developments in the treatment of sexually transmitted diseases

Recent changes in the treatment of sexually transmitted diseases include recognition of penicillin-resistant Neisseria gonorrhoeae, identification of Chlamydia trachomatis as the leading cause of bacterial genital infection in the United States, and the realization that the urethritis syndrome is often associated with multiple pathogens. There is currently no monotherapy that eradicates all STD pathogens. The role of fluoroquinolones in the treatment of STDs is still evolving. The investigational agent, temafloxacin, has good activity against gonococci, nongonococcal organisms, and, unlike other quinolones, against Bacteroides fragilis and other anaerobes. Norfloxacin, ciprofloxacin, enoxacin, ofloxacin, and temafloxacin single-dose therapy have demonstrated clinical efficacy for gonococcal infections in non-comparative and comparative trials, including bacterial eradication of isolates resistant to other agents.

Oral ciprofloxacin versus ceftriaxone for the treatment of urethritis from resistant Neisseria gonorrhoeae in Zambia

Neisseria gonorrhoeae strains resistant to treatment with penicillin, tetracycline, and/or spectinomycin are increasing in prevalence in many parts of the world. In Zambia, 52% of N. gonorrhoeae isolates produced beta-lactamase in 1986. Few oral regimens have proven effective for treatment of resistant N. gonorrhoeae. We conducted a prospective, double-blind, randomized clinical trial of 250 mg of ciprofloxacin given orally versus 250 mg of ceftriaxone given intramuscularly for treatment of uncomplicated gonococcal urethritis in adult males. Two hundred men were enrolled and treated. The two groups were comparable in age (27.5 years), prevalence of latent syphilis (14 and 10%), and human immunodeficiency virus infection (32 and 38%). Of 165 patients with cultures positive for N. gonorrhoeae who returned for follow-up, ciprofloxacin cured 83 of 83 (100%), including 26 with penicillinase-producing N. gonorrhoeae (PPNG) and 21 with N. gonorrhoeae with chromosomally mediated resistance to multiple antibiotics (CMRNG), and ceftriaxone cured 81 of 82 (98.7%), including 30 with PPNG and 19 with CMRNG. Both treatment regimens were well tolerated. Chlamydia trachomatis in urethral exudate was found by direct fluorescent-antibody microscopic examination or by culture in 10 (5%) participants. All N. gonorrhoeae isolates were inhibited by ceftriaxone at 0.06 micrograms/ml, except one which was inhibited at 0.125 micrograms/ml, while ciprofloxacin inhibited all isolates at 0.03 micrograms/ml. Ciprofloxacin is a safe and effective therapy for uncomplicated gonococcal urethritis, including that caused by PPNG and CMRNG in human immunodeficiency virus-infected men.