Ciprofloxacin resistance and gonorrhea incidence rates in 17 cities, United States, 1991-2006

Stimulating Transcription in Antibiotic-Tolerant Escherichia coli Sensitizes It to Fluoroquinolone and Nonfluoroquinolone Topoisomerase Inhibitors

Antibiotic tolerant bacteria and persistent cells that remain alive after a course of antibiotic treatment can foster the chronicity of infections and the development of antibiotic resistance. Elucidating how bacteria overcome antibiotic action and devising strategies to bolster a new drug's activity can allow us to preserve our antibiotic arsenal. Here, we investigate strategies to potentiate the activities of topoisomerase inhibitors against nongrowing Escherichia coli that are often recalcitrant to existing antibiotics. We focus on sensitizing bacteria to the fluoroquinolone (FQ) levofloxacin (Levo) and to the spiropyrimidinetrione zoliflodacin (Zoli)-the first antibiotic in its class of compounds in clinical development. We found that metabolic stimulation either alone or in combination with inhibiting the AcrAB-TolC efflux pump sensitized stationary-phase E. coli to Levo and Zoli. We demonstrate that the added metabolites increased proton motive force generation and ATP production in stationary-phase cultures without restarting growth. Instead, the stimulated bacteria increased transcription and translation, which rendered the populations more susceptible to topoisomerase inhibitors. Our findings illuminate potential vulnerabilities of antibiotic-tolerant bacteria that can be leveraged to sensitize them to new and existing classes of topoisomerase inhibitors. These approaches enable us to stay one step ahead of adaptive bacteria and safeguard the efficacy of our existing antibiotics.

The resistance mechanisms of bacteria against ciprofloxacin and new approaches for enhancing the efficacy of this antibiotic

For around three decades, the fluoroquinolone (FQ) antibiotic ciprofloxacin has been used to treat a range of diseases, including chronic otorrhea, endocarditis, lower respiratory tract, gastrointestinal, skin and soft tissue, and urinary tract infections. Ciprofloxacin's main mode of action is to stop DNA replication by blocking the A subunit of DNA gyrase and having an extra impact on the substances in cell walls. Available in intravenous and oral formulations, ciprofloxacin reaches therapeutic concentrations in the majority of tissues and bodily fluids with a low possibility for side effects. Despite the outstanding qualities of this antibiotic, Salmonella typhi, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa have all shown an increase in ciprofloxacin resistance over time. The rise of infections that are resistant to ciprofloxacin shows that new pharmacological synergisms and derivatives are required. To this end, ciprofloxacin may be more effective against the biofilm community of microorganisms and multi-drug resistant isolates when combined with a variety of antibacterial agents, such as antibiotics from various classes, nanoparticles, natural products, bacteriophages, and photodynamic therapy. This review focuses on the resistance mechanisms of bacteria against ciprofloxacin and new approaches for enhancing its efficacy.

Horizontal Gene Transfer of Fluoroquinolone Resistance-Conferring Genes From Commensal Neisseria to Neisseria gonorrhoeae: A Global Phylogenetic Analysis of 20,047 Isolates

Antimicrobial resistance in Neisseria gonorrhoeae is an important global health concern. The genetically related commensal Neisseria act as a reservoir of resistance genes, and horizontal gene transfer (HGT) has been shown to play an important role in the genesis of resistance to cephalosporins and macrolides in N. gonorrhoeae. In this study, we evaluated if there was evidence of HGT in the genes gyrA/gyrB and parC/parE responsible for fluoroquinolone resistance. Even though the role of gyrB and parE in quinolone resistance is unclear, the subunits gyrB and parE were included as zoliflodacin, a promising new drug to treat N. gonorrhoeae targets the gyrB subunit. We analyzed a collection of 20,047 isolates; 18,800 N. gonorrhoeae, 1,238 commensal Neisseria spp., and nine Neisseria meningitidis. Comparative genomic analyses identified HGT events in genes, gyrA, gyrB, parC, and parE. Recombination events were predicted in N. gonorrhoeae and Neisseria commensals. Neisseria lactamica, Neisseria macacae, and Neisseria mucosa were identified as likely progenitors of the HGT events in gyrA, gyrB, and parE, respectively.

Characterization of a Neisseria gonorrhoeae Ciprofloxacin panel for an antimicrobial resistant Isolate Bank

Objectives

Neisseria gonorrhoeae (gonococcus) infection is one of the most commonly reported nationally notifiable conditions in the United States. Gonococcus has developed antimicrobial resistance to each previously used antibiotic for gonorrhea therapy. However, some isolates may be still susceptible to no longer recommended, yet still effective antibiotics. This in turn suggests that targeted therapy could slow resistance development to currently recommended empirical treatments. We curated a gonococcal Ciprofloxacin Antibiotic Resistance Isolate Bank panel (Cipro-panel) as a tool for validating or developing new tests to determine ciprofloxacin susceptibility.

Method

The Cipro-panel was selected using whole genome sequencing, bioinformatic tools, and antimicrobial susceptibility testing (AST) data. Isolates were further selected based on nucleotide variations in gyrA and parC genes.

Results

We selected 14 unique N. gonorrhoeae isolates from the 2006–2012 Gonococcal Isolate Surveillance Project (GISP) collection. They represented a wide range of antimicrobial susceptibility to ciprofloxacin and commonly observed nucleotide variations of gyrA and parC genes. This Cipro-panel consists of 5 isolates with resistant phenotypes (MIC > = 1 μg/mL), 8 isolates with susceptible phenotypes (MIC < = 0.06 μg/mL), and 1 isolate falling in the Clinical and Laboratory Standards Institute defined intermediate range. Among the gyrA variations we observed a total of 18 SNPs. Four positions had nonsynonymous changes (nucleotide positions 272, 284, 1093, and 1783). The first two positions (272 and 284) have been linked previously with resistance to ciprofloxacin (i.e. amino acid positions 91 and 95). For the parC gene, we observed a total of 21 possible SNPs. Eight of those SNPs resulted in non-synonymous amino acid changes. One location (amino acid 87) has been previously reported to be associated with ciprofloxacin resistance.

Conclusions

This Cipro-Panel is useful for researchers interested in developing clinical tests related to ciprofloxacin. It could also provide additional choices for validation, quality assurance purposes and improve antibiotic usage.

Molecular Epidemiology, Antimicrobial Surveillance, and PK/PD Analysis to Guide the Treatment of Neisseria gonorrhoeae Infections

The aim of this study was to apply molecular epidemiology, antimicrobial surveillance, and PK/PD analysis to guide the antimicrobial treatment of gonococci infections in a region of the north of Spain. Antibiotic susceptibility testing was performed on all isolates (2017 to 2019, n = 202). A subset of 35 isolates intermediate or resistant to at least two antimicrobials were selected to search for resistance genes and genotyping through WGS. By Monte Carlo simulation, we estimated the probability of target attainment (PTA) and the cumulative fraction of response (CFR) of the antimicrobials used to treat gonorrhea, both indicative of the probability of treatment success. In total, 2.0%, 6.4%, 5.4%, and 48.2% of the isolates were resistant to ceftriaxone, cefixime, azithromycin, and ciprofloxacin, respectively. Twenty sequence types were identified. Detected mutations were related to antibiotic resistance. PK/PD analysis showed high probability of treatment success of the cephalosporins. In conclusion, multiple populations of N. gonorrhoeae were identified. We can confirm that ceftriaxone (even at the lowest dose: 250 mg) and oral cefixime are good candidates to treat gonorrhea. For patients allergic to cephalosporins, ciprofloxacin should be only used if the MIC is known and ≤0.125 mg/L; this antimicrobial is not recommended for empirical treatment.

Applying a novel approach to scoping review incorporating artificial intelligence: mapping the natural history of gonorrhoea

BACKGROUND

Systematic and scoping literature searches are increasingly resource intensive. We present the results of a scoping review which combines the use of a novel artificial-intelligence-(AI)-assisted Medline search tool with two other 'traditional' literature search methods. We illustrate this novel approach with a case study to identify and map the range of conditions (clinical presentations, complications, coinfections and health problems) associated with gonorrhoea infection.

METHODS

To fully characterize the range of health outcomes associated with gonorrhoea, we combined a high yield preliminary search with a traditional systematic search, then supplemented with the output of a novel AI-assisted Medline search tool based on natural language processing methods to identify eligible literature.

RESULTS

We identified 189 health conditions associated with gonorrhoea infection of which: 53 were identified through the initial 'high yield' search; 99 through the systematic search; and 124 through the AI-assisted search. These were extracted from 107 unique references and 21 International Statistical Classification of Diseases and Related Health Problems Ninth and Tenth Revision (ICD 9/10) or Read codes. Health conditions were mapped to the urogenital tract (n = 86), anorectal tract (n = 6) oropharyngeal tract (n = 5) and the eye (n = 14); and other conditions such as systemic (n = 61) and neonatal conditions (n = 7), psychosocial associations (n = 3), and co-infections (n = 7). The 107 unique references attained a Scottish Intercollegiate Guidelines Network (SIGN) score of ≥2++ (n = 2), 2+ (14 [13%]), 2- (30 [28%]) and 3 (45 [42%]), respectively. The remaining papers (n = 16) were reviews.

CONCLUSIONS

Through AI screening of Medline, we captured - titles, abstracts, case reports and case series related to rare but serious health conditions related to gonorrhoea infection. These outcomes might otherwise have been missed during a systematic search. The AI-assisted search provided a useful addition to traditional/manual literature searches especially when rapid results are required in an exploratory setting.

More Screening or More Disease? Gonorrhea Testing and Positivity Patterns Among Men in 3 Large Clinical Practices in Massachusetts, 2010-2017

BACKGROUND

Gonorrhea diagnosis rates in the United States increased by 75% during 2009-2017, predominantly in men. It is unclear whether the increase among men is being driven by more screening, an increase in the prevalence of disease, or both. We sought to evaluate changes in gonorrhea testing patterns and positivity among men in Massachusetts.

METHODS

The analysis included men (aged ≥15 years) who received care during 2010-2017 in 3 clinical practice groups. We calculated annual percentages of men with ≥1 gonorrhea test and men with ≥1 positive result, among men tested. Log-binomial regression models were used to examine trends in these outcomes. We adjusted for clinical and demographic characteristics that may influence the predilection to test and probability of gonorrhea disease.

RESULTS

On average, 306 348 men had clinical encounters each year. There was a significant increase in men with ≥1 gonorrhea test from 2010 (3.1%) to 2017 (6.4%; adjusted annual risk ratio, 1.12; 95% confidence interval, 1.12-1.13). There was a significant, albeit lesser, increase in the percentage of tested men with ≥1 positive result (1.0% in 2010 to 1.5% in 2017; adjusted annual risk ratio, 1.07; 95% confidence interval, 1.04-1.09).

CONCLUSIONS

We estimated significant increases in the annual percentages of men with ≥1 gonorrhea test and men with ≥1 positive gonorrhea test result between 2010 and 2017. These results suggest that observed increases in gonorrhea rates could be explained by both increases in screening and the prevalence of gonorrhea.

Addressing Neisseria gonorrhoeae Treatment Resistance With the DNA Gyrase A Assay: An Economic Study, United States

Targeted antibiotics could delay emergence of resistant Neisseria gonorrhoeae. The DNA gyrase subunit A assay predicts susceptibility to ciprofloxacin. A model found that adding a $50 gyrase subunit A test for asymptomatic patients screened for N. gonorrhoeae resulted in cost neutrality. When ciprofloxacin susceptibility was high, a $114 test resulted in savings.

Outcome Impacts Due to Pathogen-Specific Antimicrobial Resistance: A Narrative Review of Published Literature

Antimicrobial resistance (AMR) has become a global threat to not only public health impacts but also clinical and economic outcomes. During the past decades, there have been many studies focusing on surveillance, mechanisms, and diagnostics of AMR in infectious diseases but the impacts on public health, clinical and economic outcomes due to emergence of these AMRs are rarely studied and reported. This review was aimed to summarize the findings from published studies to report the outcome impacts due to AMR of malaria, tuberculosis and HIV and briefly discuss the implications for application to other infectious diseases. PubMed/Medline and Google Scholar databases were used for search of empirical and peer-reviewed papers reporting public health, clinical and economic outcomes due to AMR of malaria, tuberculosis and HIV. Papers published through 1 December 2019 were included in this review. A total of 76 studies were included for this review, including 16, 49 and 11 on public health, clinical and economic outcomes, respectively. The synthesized data indicated that the emergence and spread of AMR of malaria, tuberculosis and HIV have resulted in adverse public health, clinical and economic outcomes. AMR of malaria, tuberculosis and HIV results in significant adverse impacts on public health, clinical and economic outcomes. Evidence from this review suggests the needs to consider the similar studies for other infectious diseases.

The type-reproduction number of sexually transmitted infections through heterosexual and vertical transmission

Multiple sexually transmitted infections (STIs) have threatened human health for centuries. Most STIs spread not only through sexual (horizontal) transmission but also through mother-to-child (vertical) transmission. In a previous work (Ito et al. 2019), we studied a simple model including heterosexual and mother-to-child transmission and proposed a formulation of the basic reproduction number over generations. In the present study, we improved the model to take into account some factors neglected in the previous work: adult mortality from infection, infant mortality caused by mother-to-child transmission, infertility or stillbirth caused by infection, and recovery with treatment. We showed that the addition of these factors has no essential effect on the theoretical formulation. To study the characteristics of the epidemic threshold, we derived analytical formulas for three type-reproduction numbers for adult men, adult women and juveniles. Our result indicates that if an efficient vaccine exists for a prevalent STI, vaccination of females is more effective for containment of the STI than vaccination of males, because the type-reproduction number for adult men is larger than that for adult women when they are larger than one.

The Impact of Budget Cuts on Sexually Transmitted Disease Programmatic Activities in State and Local Health Departments With Staffing Reductions in Fiscal Year 2012

Staffing reductions in state and local health departments in fiscal year 2012 were concentrated in disease investigation specialists and clinicians (local) and disease investigation specialists and administrative staff (state). Local health departments with budget cuts were significantly more likely to report reduced partner services if they had staffing reductions.

An Illustration of the Potential Health and Economic Benefits of Combating Antibiotic-Resistant Gonorrhea

Preventing the emergence of ceftriaxone-resistant Neisseria gonorrhoeae can potentially avert hundreds of millions of dollars in direct medical costs of gonorrhea and gonorrhea-attributable HIV infections. In the illustrative scenario we examined, emerging ceftriaxone resistance could lead to 1.2 million additional N. gonorrhoeae infections within 10 years, costing $378.2 million.

Liquid crystal delivery of ciprofloxacin to treat infections of the female reproductive tract

Infections of the female reproductive tract are a major cause of morbidity and mortality in humans, requiring significant investment to sustain treatment and representing a major challenge to health. The increasing prevalence of bacterial resistance, and an almost complete absence of new antibiotic therapies for the past five decades, mean there is a desperate need for novel approaches to the treatment of bacterial infections. Within the present study, we demonstrate the effective ex vivo treatment of bacterial infection of the female reproductive tract using a controlled-release, liquid crystal-based platform. Liquid crystal encapsulation of ciprofloxacin significantly enhanced its bactericidal efficacy and reduced cell toxicity. Liquid crystal structures are low-cost, simple to manufacture and provide a sustained-release profile of encapsulated ciprofloxacin. Treatment of Escherichia coli infected reproductive tract epithelial cells and whole organ cultures with liquid crystal encapsulated ciprofloxacin proved to be an effective strategy for reducing bacterial load and reproductive tract inflammatory responses to infection. These data suggest that such an approach could provide an efficacious treatment modality for enhancing the effectiveness of current antibiotic therapies.

Antimicrobial resistance of Neisseria gonorrhoeae isolates in south-west Germany, 2004 to 2015: increasing minimal inhibitory concentrations of tetracycline but no resistance to third-generation cephalosporins

Increasing antimicrobial resistance of Neisseria gonorrhoeae, particularly to third-generation cephalosporins, has been reported in many countries. We examined the susceptibility (determined by Etest and evaluated using the breakpoints of the European Committee on Antimicrobial Susceptibility Testing) of 434 N. gonorrhoeae isolates collected from 107 female and 327 male patients in Stuttgart, south-west Germany, between 2004 and 2015. During the study period, high proportions of isolates were resistant to ciprofloxacin (70.3%), tetracycline (48.4%; increasing from 27.5% in 2004/2005 to 57.7% in 2014/2015; p = 0.0002) and penicillin (25.6%). The proportion of isolates resistant to azithromycin was low (5.5%) but tended to increase (p = 0.08). No resistance and stable minimum inhibitory concentrations were found for cefixime, ceftriaxone, and spectinomycin. High-level resistance was found for ciprofloxacin (39.6%) and tetracycline (20.0%) but not for azithromycin; 16.3% of the isolates produced betalactamase. Thus, cephalosporins can still be used for the treatment of gonorrhoea in the study area. To avoid further increasing resistance to azithromycin, its usage should be limited to patients allergic to cephalosporins, or (in combination with cephalosporins) to patients for whom no susceptibility testing could be performed or those co-infected with chlamydiae.