Central metabolism is a key player in E. coli biofilm stimulation by sub-MIC antibiotics.

Exposure of Escherichia coli to sub-inhibitory antibiotics stimulates biofilm formation through poorly characterized mechanisms. Using a high-throughput Congo Red binding assay to report on biofilm matrix production, we screened ~4000 E. coli K12 deletion mutants for deficiencies in this biofilm stimulation response. We screened using three different antibiotics to identify core components of the biofilm stimulation response. Mutants lacking acnA, nuoE, or lpdA failed to respond to sub-MIC cefixime and novobiocin, implicating central metabolism and aerobic respiration in biofilm stimulation. These genes are members of the ArcA/B regulon-controlled by a respiration-sensitive two-component system. Mutants of arcA and arcB had a 'pre-activated' phenotype, where biofilm formation was already high relative to wild type in vehicle control conditions, and failed to increase further with the addition of sub-MIC cefixime. Using a tetrazolium dye and an in vivo NADH sensor, we showed spatial co-localization of increased metabolic activity with sub-lethal concentrations of the bactericidal antibiotics cefixime and novobiocin. Supporting a role for respiratory stress, the biofilm stimulation response to cefixime and novobiocin was inhibited when nitrate was provided as an alternative electron acceptor. Deletion of a gene encoding part of the machinery for respiring nitrate abolished its ameliorating effects, and nitrate respiration increased during growth with sub-MIC cefixime. Finally, in probing the generalizability of biofilm stimulation, we found that the stimulation response to translation inhibitors, unlike other antibiotic classes, was minimally affected by nitrate supplementation, suggesting that targeting the ribosome stimulates biofilm formation in distinct ways. By characterizing the biofilm stimulation response to sub-MIC antibiotics at a systems level, we identified multiple avenues for design of therapeutics that impair bacterial stress management.

Detection of antimicrobial resistance in <5 h in Neisseria gonorrhoeae isolates using flow cytometry-proof of concept for seven clinically relevant antimicrobials.

INTRODUCTION: Antimicrobial resistance in Neisseria gonorrhoeae compromises gonorrhoea treatment and rapid antimicrobial susceptibility testing (AST) would be valuable. We have developed a rapid and accurate flow cytometry method (FCM) for AST of gonococci. METHODS: The 2016 WHO gonococcal reference strains, and WHO Q, R and S (n = 17) were tested against seven clinically relevant antibiotics (ceftriaxone, cefixime, azithromycin, spectinomycin, ciprofloxacin, tetracycline and gentamicin). After 4.5 h incubation of inoculated broth, the fluorescent dye Syto™ 9 was added, followed by FCM analysis. After gating, the relative remaining population of gonococci, compared with unexposed growth control samples, was plotted against antimicrobial concentration, followed by non-linear curve regression analysis. Furthermore, the response at one single concentration/tested antibiotic was evaluated with the intention to use as a screening test for detection of resistant gonococci. RESULTS: A dose-dependent response was seen in susceptible isolates for all tested antimicrobials. There was a clear separation between susceptible/WT and resistant/non-WT isolates for ceftriaxone, cefixime, spectinomycin, ciprofloxacin and tetracycline. In contrast, for azithromycin, only high-level-resistant isolates were distinguished, while resistant isolates with MICs of 4 mg/L were indistinguishable from WT (MIC ≤ 1 mg/L) isolates. For gentamicin, all tested 17 isolates were WT and FCM analysis resulted in uniform dose-response curves. Using a single antibiotic concentration and a 50% remaining cell population cut-off, the overall sensitivity and specificity for resistance detection were 93% and 99%, respectively. CONCLUSIONS: By providing results in <5 h for gonococcal isolates, FCM-based AST can become a rapid screening method for antimicrobial resistance or antimicrobial susceptibility in gonococci.

Recent dynamics in Neisseria gonorrhoeae genomic epidemiology in Brazil: antimicrobial resistance and genomic lineages in 2017-20 compared to 2015-16.

OBJECTIVES: Regular quality-assured WGS with antimicrobial resistance (AMR) and epidemiological data of patients is imperative to elucidate the shifting gonorrhoea epidemiology, nationally and internationally. We describe the dynamics of the gonococcal population in 11 cities in Brazil between 2017 and 2020 and elucidate emerging and disappearing gonococcal lineages associated with AMR, compare to Brazilian WGS and AMR data from 2015 to 2016, and explain recent changes in gonococcal AMR and gonorrhoea epidemiology. METHODS: WGS was performed using Illumina NextSeq 550 and genomes of 623 gonococcal isolates were used for downstream analysis. Molecular typing and AMR determinants were obtained and links between genomic lineages and AMR (determined by agar dilution/Etest) examined. RESULTS: Azithromycin resistance (15.6%, 97/623) had substantially increased and was mainly explained by clonal expansions of strains with 23S rRNA C2611T (mostly NG-STAR CC124) and mtr mosaics (mostly NG-STAR CC63, MLST ST9363). Resistance to ceftriaxone and cefixime remained at the same levels as in 2015-16, i.e. at 0% and 0.2% (1/623), respectively. Regarding novel gonorrhoea treatments, no known zoliflodacin-resistance gyrB mutations or gepotidacin-resistance gyrA mutations were found. Genomic lineages and sublineages showed a phylogenomic shift from sublineage A5 to sublineages A1-A4, while isolates within lineage B remained diverse in Brazil. CONCLUSIONS: Azithromycin resistance, mainly caused by 23S rRNA C2611T and mtrD mosaics/semi-mosaics, had substantially increased in Brazil. This mostly low-level azithromycin resistance may threaten the recommended ceftriaxone-azithromycin therapy, but the lack of ceftriaxone resistance is encouraging. Enhanced gonococcal AMR surveillance, including WGS, is imperative in Brazil and other Latin American and Caribbean countries.

Minimum inhibitory concentrations of Neisseria gonorrhoeae strains in clients of the Amsterdam sexual health clinic with a Dutch versus an international sexual network.

OBJECTIVES: International travel combined with sex may contribute to dissemination of antimicrobial-resistant (AMR) Neisseria gonorrhoeae (Ng). To assess the role of travel in Ng strain susceptibility, we compared minimum inhibitory concentrations (MICs) for five antibiotics (ie, azithromycin, ceftriaxone, cefotaxime, cefixime and ciprofloxacin) in strains from clients with an exclusively Dutch sexual network and clients with an additional international sexual network. METHODS: From 2013 to 2019, we recorded recent residence of sexual partners of clients (and of their partners) with Ng at the Center for Sexual Health of Amsterdam. We categorised clients as having: (1) exclusively sexual partners residing in the Netherlands ('Dutch only') or (2) at least one partner residing outside the Netherlands. We categorised the country of residence of sexual partners by World Bank/EuroVoc regions. We analysed the difference of log-transformed MIC of Ng strains between categories using linear or hurdle regression for each antibiotic. RESULTS: We included 3367 gay and bisexual men who had sex with men (GBMSM), 516 women and 525 men who exclusively had sex with women (MSW) with Ng. Compared with GBMSM with a 'Dutch only' network, GBMSM with: (1) a Western European network had higher MICs for ceftriaxone (ß=0.19, 95% CI=0.08 to 0.29), cefotaxime (ß=0.19, 95% CI=0.08 to 0.31) and cefixime (ß=0.06, 95% CI=0.001 to 0.11); (2) a Southern European network had a higher MIC for cefixime (ß=0.10, 95% CI=0.02 to 0.17); and (3) a sub-Saharan African network had a lower MIC for ciprofloxacin (ß=-1.79, 95% CI=-2.84 to -0.74). In women and MSW, higher MICs were found for ceftriaxone in clients with a Latin American and Caribbean network (ß=0.26, 95% CI=0.02 to 0.51). CONCLUSIONS: For three cephalosporin antibiotics, we found Ng strains with slightly higher MICs in clients with partner(s) from Europe or Latin America and the Caribbean. International travel might contribute to the spread of Ng with lower susceptibility. More understanding of the emergence of AMR Ng is needed.

Cefixime loaded bare and functionalized halloysite nanocarriers and their biomedical applications.

Effective drug delivery for is the foremost requirement for the complete recovery of the disease. Nanomedicine and nanoengineering has provided so many spaces and ideas for the drug delivery design, whether controlled, targeted, or sustained. Different types of nanocarriers or nanoparticles are aggressively designed for the drug delivery applications. Clay minerals are identified as a one of the potential nanocarrier for the drug delivery. Owing to their biocompatibility and very low cytotoxicity, clay minerals showing effective therapeutic applications. In the present investigation, clay mineral, i.e., Halloysite nano tubes are utilized as a nanocarrier for the delivery of antibiotic cefixime (CFX), a third-generation cephalosporin. The HNT was first functionalized with the sulfuric acid and then further treated with the 3-(aminopropyl)triethoxysilane (APTES). The drug is loaded on three different classifications of HNTs, i.e., Bare-CFX-HNT, Acid-CFX-HNT, and APTES-CFX-HNT and their comparative analysis is established. Different characterization techniques such as X-ray diffractometry (XRD), Fourier transform infra-red (FT-IR), Transmission electron microscopy TEM), Brunauer-Emmett-Teller (BET), adsorption studies, and Thermogravimetric analysis (TGA) were performed to evaluate their chemical, structural, morphological, and thermal properties. TGA confirmed the encapsulation efficiency of Bare-CFX-HNT, Acid-CFX-HNT, and APTES-CFX-HNT as 42.65, 52.19, and 53.43%, respectively. Disk diffusion and MTT assay confirmed that the drug loaded HNTs have potential antibacterial activities and less cytotoxicity. The adsorption capacity of CFX with different HNTs are evaluated and Different adsorption and kinetic models have been discussed. Drug release studies shows that APTES-CFX-HNT showing sustained release of cefixime as compared to Bare-CFX-HNT and Acid-CFX-HNT.

A case study of impaired consciousness caused by alcohol consumption in a pediatric patient taking high-dose cefixime.

A variety of drugs have been known to induce disulfiram-like reactions in individuals exposed to ethanol, including certain cephalosporin antibiotics with methylthiotetrazole (MTT) substituents or methylthiodioxotriazine (MTDT) rings. Among cephalosporins, cefixime is known to cause fewer disulfiram-like reactions. This case report, the first involving a pediatric patient, presents the scenario of a 14-year-old female who exhibited drowsiness, loss of consciousness, and cold extremities within an hour after ingesting 9 cefixime capsules. Upon admission, drug intoxication was considered, prompting immediate gastric lavage and toxicology tests, which revealed the presence of both cefixime and alcohol. Subsequent monitoring of vital signs, rehydration, and symptomatic treatments aimed at facilitating toxic excretion were administered during hospitalization. Following initial assessment by a clinical pharmacist, drug intoxication was deemed improbable, though an atypical disulfiram-like reaction or alcohol intoxication could not be ruled out. Further evaluation, coupled with the child's cefixime overdose, suggested an atypical disulfiram-like reaction. This case underscores the potential for disulfiram reactions even with cephalosporins lacking MTT substituents or MTDT rings. Notably, it is the first report of an atypical disulfiram-like reaction triggered by alcohol consumption following cefixime overdose, emphasizing the importance of caution in cefixime usage and avoidance of alcohol or alcohol-containing substances.

Using CHROMagar™ STEC medium exclusively does not recover all clinically relevant Shiga toxin-producing Escherichia coli in Aotearoa, New Zealand.

Diagnostic laboratories in Aotearoa, New Zealand (NZ) refer cultures from faecal samples positive for Shiga toxin genes to the national Enteric Reference Laboratory for isolation of Shiga toxin-producing Escherichia coli (STEC) for epidemiological typing. As there was variation in the culture media being referred, a panel of 75 clinical isolates of STEC, representing 28 different serotypes, was used to assess six commercially available media and provide guidance to clinical laboratories. Recommendations were subsequently tested for a 3-month period, where STEC isolations and confirmations were assessed by whole genome sequencing analysis against the culture media referred. CHROMagar™ STEC (CH-STEC; CHROMagar Microbiology, Paris, France) or CH-STEC plus cefixime-tellurite sorbitol MacConkey agar was confirmed inferior to CH-STEC plus blood agar with vancomycin, cefsulodin, and cefixime (BVCC). The former resulted in fewer STEC types (n = 18) being confirmed compared to those from a combination of CH-STEC and BVCC (n = 42). A significant (P < .05) association with an STEC's ability to grow on CH-STEC and the presence of the ter gene cluster, and eae was observed. Culturing screen positive STEC samples onto both CH-STEC and BVCC ensures a consistently higher recovery of STEC from all clinical samples in NZ than CH-STEC alone.

Degradation of cefixime by photocatalysis via Ba-doped BiFeO3 nanomaterial using RSM analysis under LED light source.

In the current work, Response Surface Methodology (RSM)-a statistical method-is used to optimize procedures like photocatalysis with the least amount of laboratory testing. However, to determine the most effective model for achieving the maximum rate of removal efficiency, the Response Surface Methodology was employed. The Ba-doped BiFeO3 photocatalyst was synthesized by the co-precipitation method, and its intrinsic properties were investigated by utilizing a range of spectroscopic techniques, such as FESEM, EDX, XRD, FTIR, and UV-vis. Herein, four independent factors such as, pH, contact time, pollutant concentration, and catalyst dosage were chosen. The results revealed that under acidic conditions with a contact duration of 2 min, a moderate catalyst dosage, and higher pollutant concentration, a degradation rate of 89.8% was achieved. The regression coefficient (R2) and probability value (P) were determined to be 0.99551 and 0.0301, respectively, therefore confirming the excellent fit of the RSM model. Furthermore, this research investigated the potential photocatalytic degradation mechanisms of cefixime, demonstrating that the removal efficiency of cefixime is greatly influenced by the functional parameters.

Antimicrobial Resistance Profiling and Genome Analysis of the penA-60.001 Neisseria gonorrhoeae Clinical Isolates in China in 2021.

BACKGROUND: Neisseria gonorrhoeae antimicrobial resistance (AMR) is an urgent public health threat. With dissemination of FC428-related clones, the efficacy of ceftriaxone has become controversial. METHODS: Agar dilution and whole genome sequencing were used to analyze AMR. RESULTS: High resistance to penicillin (75.2%), tetracycline (87.9%), ciprofloxacin (98.3%), ceftriaxone (8.9%), cefixime (14.3%), and azithromycin (8.6%) was observed among 463 isolates first collected in China in 2021. All penA-60.001 clones exhibited resistance to ceftriaxone or cefixime, and 1 of the 12 cases was resistant to azithromycin. ngMAST and ngSTAR of penA-60.001 isolates showed that single-nucleotide polymorphisms in the porB, tbpB, ponA, gyrA, and parC genes were the major causes of different sequence types. MLST-7365 (n = 5) and MLST-1903 (n = 3) were main genotypes, and the other 4 strains featured MLST-10314, MLST-13871, MLST-7827 and MLST-1600. Furthermore, resistance markers (eg, penA, blaTEM-1, blaTEM-135) and virus factors were detected. Most penA-60.001 strains were fully mixed with global FC428-related clones; 2021-A2 and F89 had the same origin; and 2021-A1 exhibited a unique evolutionary trajectory. CONCLUSIONS: Results provide the first demonstration of extremely severe AMR rates of N gonorrhoeae in China in 2021, particularly strains with ceftriaxone decreased susceptibility. The sustained transmission of penA-60.001 subclones might further threaten treatment effectiveness.

[Modern pharmacotherapy of acute bacterial sinusitis: results of an open randomized clinical trial of the therapeutic equivalence of Cefixime EXPRESS and Suprax Solutab]. / Sovremennaya farmakoterapiya ostrogo bakterial'nogo sinusita: rezul'taty otkrytogo randomizirovannogo klinicheskogo issledovaniya terapevticheskoi ekvivalentnosti preparatov «Tsefiksim EKSPRESS¼ i «Supraks Solyutab¼.

BACKGROUND: Acute bacterial sinusitis is one of the most common causes of prescribing systemic antibacterial drugs in otorhinolaryngology. With bacterial etiology of the disease, beta-lactam antibiotics are prescribed, in particular cefixim. Cefixim in the form of dispersible tablets has high clinical and bacteriological efficiency, as well as good tolerability in patients with acute sinusitis. OBJECTIVE: To study the therapeutic equivalence of two drugs of cefixim (reproduced drug Cefixim Express and reference drug Suprax Solutab) in patients with acute bacterial sinusitis. MATERIAL AND METHODS: 60 adult patients with a diagnosis of acute bacterial sinusitis took part in a randomized open comparative clinical study. Patients of group 1 (n=30) received the drug Cefixim Express in the form of dispersible tablets 400 mg once a day. Group 2 (n=30) received Suprax Solutab in the form of dispersible tablets 400 mg once a day. The duration of treatment course was 7 days. All patients conducted general clinical and otorhinolaryngological examinations, assessment of symptoms of acute sinusitis, assessment of the general clinical impression of the therapy, tolerance of treatment, analysis of the frequency of unwanted phenomena before treatment, 3 days after the beginning of therapy and after the course completion (7 days). RESULTS: Recovery occurred in 63.3% of patients in group 1 according to the inspection on the 7th day of treatment and in 66.67% of patients in group 2. The rate of clinical symptoms regression by the end of therapy was comparable in the comparison groups. Hyperemia of the nasal mucosa, purulent nasal discharge and difficulty in nasal breathing (p<0.01) regressed by the 7th day in patients of both treatment groups. The incidence of adverse reactions on the 7th day of treatment in group 1 was 10%, in group 2 - 6.7% (p>0.05). CONCLUSION: The drug Cefixim Express has high therapeutic effectiveness in the treatment of acute bacterial sinusitis, comparable to Suprax Solutab. Cefixime EXPRESS has demonstrated a good tolerability and a favorable safety profile.

Characterizing the Rise of Disseminated Gonococcal Infections in California, July 2020-July 2021.

BACKGROUND: California has experienced an increase in reported cases of disseminated gonococcal infection (DGI). Given significant morbidity associated with DGI and the ability of Neisseria gonorrhoeae to rapidly develop antibiotic resistance, characterization of these cases can inform diagnosis, management, and prevention of DGI. METHODS: As part of the public health response to increased reports of DGI, we used gonorrhea surveillance data reported to the California Department of Public Health to identify all DGI cases in a geographically-bound region. Standardized case report forms were used to collect epidemiologic risk factors and clinical information obtained from provider/laboratory reports, medical records, and patient interviews. RESULTS: From 1 July 2020 to 31 July 2021, we identified 149 DGI patients among 63 338 total gonorrhea infections, representing 0.24% of gonorrhea cases. Estimated incidence was 0.47 DGI cases per 100 000 person-years. Mean age of DGI patients was 40 years, and 75 (50%) were cisgender men, of whom only 13 were known to have male partners. Where reported, more than one-third (36%) used methamphetamine and nearly one-quarter (23%) experienced homelessness. Clinically, 61% lacked urogenital, pharyngeal, or rectal symptoms; 2 patients died in the hospital. Among 47 isolates from patients with antimicrobial susceptibility testing (AST) results available, all were susceptible to ceftriaxone and cefixime. CONCLUSIONS: Most DGI patients lacked urogenital symptoms and were not among populations for which routine gonorrhea screening is currently recommended. Expanding gonorrhea screening might prevent DGI. Cefixime is likely the best option if transitioning from parenteral to oral therapy when AST results are unavailable.

Use of genome sequencing to resolve differences in gradient diffusion and agar dilution antimicrobial susceptibility testing performance of Neisseria gonorrhoeae isolates in Alberta, Canada.

Agar dilution is the gold standard method for phenotypic antimicrobial susceptibility testing (AST) for Neisseria gonorrhoeae. However, this method is laborious and requires expertise, so laboratories that perform N. gonorrhoeae AST may choose alternative methods such as disk diffusion and gradient diffusion. In this study, we retrospectively compare the performance of gradient diffusion to agar dilution for 2,394 unique N. gonorrhoeae isolates identified in Alberta from 2017 to 2020 against azithromycin, cefixime, ceftriaxone, ciprofloxacin, penicillin, and tetracycline. Genome sequencing was utilized to resolve discrepancies between AST methods, detect antimicrobial resistance markers, and identify trends between error rates and sequence types (STs) of isolates. Over 90% of N. gonorrhoeae isolates were susceptible to azithromycin, cefixime, and ceftriaxone, whereas decreased susceptibility was observed for ciprofloxacin, penicillin, and tetracycline. Categorical (CA) and essential agreement (EA) was poorest between the two methods for penicillin (CA: 86.02%; EA: 77.69%) and tetracycline (CA: 47.22%; EA: 55.96%); however, the low CA was primarily attributed to minor errors. Antimicrobial agents with errors outside of acceptable limits included azithromycin (very major error: 18.42%; major error: 7.73%) and tetracycline (very major error: 6.17%). Genome sequencing on a subset of isolates resolved 30.3% of the azithromycin major errors and confirmed the azithromycin or tetracycline very major errors. Significant associations between certain STs and error types for azithromycin and tetracycline were also identified. Overall, gradient diffusion compared well to agar dilution for cefixime, ceftriaxone, and ciprofloxacin, and genome sequencing was identified as a useful tool to arbitrate discrepant susceptibility testing results between gradient diffusion and agar dilution for N. gonorrhoeae.

Antibacterial and anti-biofilm properties of carvacrol alone and in combination with cefixime against Escherichia coli.

BACKGROUND: Plant-derived compounds can be used as antimicrobial agents in medicines and as food preservatives. These compounds can be applied along with other antimicrobial agents to strengthen the effect and/or reduce the required treatment dose. RESULTS: In the present study, the antibacterial, anti-biofilm and quorum sensing inhibitory activity of carvacrol alone and in combination with the antibiotic cefixime against Escherichia coli was investigated. The MIC and MBC values for carvacrol were 250 µg/mL. In the checkerboard test, carvacrol showed a synergistic interaction with cefixime against E. coli (FIC index = 0.5). Carvacrol and cefixime significantly inhibited biofilm formation at MIC/2 (125 and 62.5 µg/mL), MIC/4 (62.5 and 31.25 µg/mL) and MIC/8 (31.25 and 15.625 µg/mL) for carvacrol and cefixime, respectively. The antibacterial and anti-biofilm potential effect of carvacrol confirmed by the scanning electron microscopy. Real-time quantitative reverse transcription PCR revealed significant down-regulation of the luxS and pfs genes following treatment with a MIC/2 (125 µg/mL) concentration of carvacrol alone and of only pfs gene following treatment with MIC/2 of carvacrol in combination with MIC/2 of cefixime (p < 0.05). CONCLUSIONS: Because of the significant antibacterial and anti-biofilm activity of carvacrol, the present study examines this agent as an antibacterial drug of natural origin. The results indicate that in this study the best antibacterial and anti-biofilm properties are for the combined use of cefixime and carvacrol.

Is there an association between previous infection with Neisseria gonorrhoeae and gonococcal AMR? A cross-sectional analysis of national and sentinel surveillance data in England, 2015-2019.

OBJECTIVES: Quarterly STI screening is recommended for high-risk gay, bisexual and other men who have sex with men (MSM) in the UK, but frequent antibiotic exposure could potentially increase the risk of antimicrobial resistance (AMR) developing in Neisseria gonorrhoeae. We investigated whether repeat diagnosis of gonorrhoea in those attending sexual health services (SHS) was associated with reduced antimicrobial susceptibility. METHODS: Antimicrobial susceptibility data relating to the most recent gonorrhoea diagnosis for each individual included in the Gonococcal Resistance to Antimicrobials Surveillance Programme (2015-2019) were matched to their historical records in the national GUMCAD STI surveillance data set (2012-2019). The number of gonorrhoea diagnoses in the previous 3 years was calculated for each SHS attendee. Logistic regression was used to examine the associations between the number of diagnoses and reduced susceptibility to ceftriaxone (minimum inhibitory concentration (MIC) >0.03 mg/L), cefixime (MIC >0.06 mg/L) and azithromycin (MIC >0.25 mg/L) at the time of the latest diagnosis. RESULTS: Of 6161 individuals included in the analysis, 3913 (63.5%) were MSM, 1220 (19.8%) were heterosexual men and 814 (13.2%) were women. Among MSM, 2476 (63.3%) had 1 past gonorrhoea diagnosis, 1295 (33.1%) had 2-4, 140 (3.6%) 5-9, and 2 (0.1%) ≥10. Most women and heterosexual men (91.7%) had one past gonorrhoea diagnosis; none had more than four. Reduced ceftriaxone and cefixime susceptibility was more common among MSM with two to four gonorrhoea diagnoses (3.8% and 5.8%, respectively) compared with those with one (2.2% and 3.9%, respectively). After adjusting for potential confounding, this association remained (adjusted OR: 1.59, 95% CI 1.07 to 2.37, p=0.02; adjusted OR: 1.54, 95% CI 1.11 to 2.14, p=0.01). No evidence was found for any other associations. CONCLUSIONS: Among MSM, repeat diagnosis of gonorrhoea may be associated with reduced ceftriaxone and cefixime susceptibility. As these are last-line therapies for gonorrhoea, further research is needed to assess the impact of intensive STI screening on AMR.

Effectiveness of Cefixime for the Treatment of Neisseria gonorrhoeae Infection at 3 Anatomic Sites: A Systematic Review and Meta-Analysis.

BACKGROUND: To treat Neisseria gonorrhoeae infection, the Centers for Disease Control and Prevention recommends a single oral dose of cefixime as an alternative to injectable ceftriaxone. METHODS: We conducted a systematic review and meta-analysis to describe the effectiveness of cefixime in treating N. gonorrhoeae infection at 3 different anatomic sites.We searched PubMed and Embase database to abstract treatment success rates and cefixime dosage/frequency for studies that reported the anatomical site of infection. We included reports published between January 1, 1980, and December 7, 2021. Twenty studies published between 1989 and 2015 were included in our meta-analysis. We calculated pooled treatment success percentages and 95% confidence intervals (CIs) using random-effects models. RESULTS: Of patients who received a 400-mg single dose of cefixime, 824 of 846 (97%; 95% CI, 96%-98%) patients with urogenital infection, 107 of 112 (97%; 95% CI, 84%-100%) patients with rectal infection, and 202 of 242 (89%; 95% CI, 76%-96%) patients with pharyngeal infection were cured. Of patients who received an 800-mg single dose of cefixime, 295 of 301 (98%; 95% CI, 96%-99%) patients with urogenital infection and 21 of 26 (81%; 95% CI, 61%-92%) patients with pharyngeal infection were cured. CONCLUSIONS: Our meta-analysis found that cefixime is highly effective at treating urogenital infections and less effective at treating pharyngeal infections. We recommend more investigation into the effectiveness of cefixime in treating rectal infections and studying multidose therapy for the cefixime treatment of pharyngeal infection.

Covalent docking and molecular dynamics simulations reveal the specificity-shifting mutations Ala237Arg and Ala237Lys in TEM beta-lactamase.

The rate of modern drug discovery using experimental screening methods still lags behind the rate at which pathogens mutate, underscoring the need for fast and accurate predictive simulations of protein evolution. Multidrug-resistant bacteria evade our defenses by expressing a series of proteins, the most famous of which is the 29-kilodalton enzyme, TEM ß-lactamase. Considering these challenges, we applied a covalent docking heuristic to measure the effects of all possible alanine 237 substitutions in TEM due to this codon's importance for catalysis and effects on the binding affinities of commercially-available ß-lactam compounds. In addition to the usual mutations that reduce substrate binding due to steric hindrance, we identified two distinctive specificity-shifting TEM mutations, Ala237Arg and Ala237Lys, and their respective modes of action. Notably, we discovered and verified through minimum inhibitory concentration assays that, while these mutations and their bulkier side chains lead to steric clashes that curtail ampicillin binding, these same groups foster salt bridges with the negatively-charged side-chain of the cephalosporin cefixime, widely used in the clinic to treat multi-resistant bacterial infections. To measure the stability of these unexpected interactions, we used molecular dynamics simulations and found the binding modes to be stable despite the application of biasing forces. Finally, we found that both TEM mutants also bind strongly to other drugs containing negatively-charged R-groups, such as carumonam and ceftibuten. As with cefixime, this increased binding affinity stems from a salt bridge between the compounds' negative moieties and the positively-charged side chain of the arginine or lysine, suggesting a shared mechanism. In addition to reaffirming the power of using simulations as molecular microscopes, our results can guide the rational design of next-generation ß-lactam antibiotics and bring the community closer to retaking the lead against the recurrent threat of multidrug-resistant pathogens.

Projecting the development of antimicrobial resistance in Neisseria gonorrhoeae from antimicrobial surveillance data: a mathematical modelling study.

BACKGROUND: The World Health Organization recommends changing the first-line antimicrobial treatment for gonorrhoea when ≥ 5% of Neisseria gonorrhoeae cases fail treatment or are resistant. Susceptibility to ceftriaxone, the last remaining treatment option has been decreasing in many countries. We used antimicrobial resistance surveillance data and developed mathematical models to project the time to reach the 5% threshold for resistance to first-line antimicrobials used for N. gonorrhoeae. METHODS: We used data from the Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP) in England and Wales from 2000-2018 about minimum inhibitory concentrations (MIC) for ciprofloxacin, azithromycin, cefixime and ceftriaxone and antimicrobial treatment in two groups, heterosexual men and women (HMW) and men who have sex with men (MSM). We developed two susceptible-infected-susceptible models to fit these data and produce projections of the proportion of resistance until 2030. The single-step model represents the situation in which a single mutation results in antimicrobial resistance. In the multi-step model, the sequential accumulation of resistance mutations is reflected by changes in the MIC distribution. RESULTS: The single-step model described resistance to ciprofloxacin well. Both single-step and multi-step models could describe azithromycin and cefixime resistance, with projected resistance levels higher with the multi-step than the single step model. For ceftriaxone, with very few observed cases of full resistance, the multi-step model was needed to describe long-term dynamics of resistance. Extrapolating from the observed upward drift in MIC values, the multi-step model projected ≥ 5% resistance to ceftriaxone could be reached by 2030, based on treatment pressure alone. Ceftriaxone resistance was projected to rise to 13.2% (95% credible interval [CrI]: 0.7-44.8%) among HMW and 19.6% (95%CrI: 2.6-54.4%) among MSM by 2030. CONCLUSIONS: New first-line antimicrobials for gonorrhoea treatment are needed. In the meantime, public health authorities should strengthen surveillance for AMR in N. gonorrhoeae and implement strategies for continued antimicrobial stewardship. Our models show the utility of long-term representative surveillance of gonococcal antimicrobial susceptibility data and can be adapted for use in, and for comparison with, other countries.

Cefixime-tellurite-deoxycholate tryptic soy broth (CTD-TSB), a selective enrichment medium, for enhancing isolation of Escherichia albertii from wild raccoon fecal samples.

AIM: The aim of this study was to develop a selective enrichment broth for efficient isolation of Escherichia albertii. METHODS AND RESULTS: A total of 412 raccoon rectal swabs suspended in PBS (phosphate-buffered saline) were tested by a real-time PCR to quantify the number of E. albertii followed by its isolation. The number of E. albertii in the PBS suspension strongly affected the isolation rate (1.2%-89%), which notably dropped (≤33%) when the number was <4 log10 CFU ml-1. However, enrichment of PBS suspension containing raccoon feces in tryptic soy broth containing cefixime, tellurite, and deoxycholate (CTD-TSB), the selective medium developed in this study, remarkably improved the isolation efficiency (up to 48%) of E. albertii. CONCLUSIONS: CTD-TSB is a useful enrichment culture medium for E. albertii and contributes to increase its isolation rate.

Dissemination of Neisseria gonorrhoeae with decreased susceptibility to extended-spectrum cephalosporins in Southern China, 2021: a genome-wide surveillance from 20 cities.

BACKGROUND: Antimicrobial resistance (AMR) of untreatable gonococcal infection is an emerging threat, especially in Guangdong, a prosperous province in Southern China. METHODS: N.gonorrhoeae was isolated from 20 cities in Guangdong and determined antimicrobial susceptibility. Through whole-genome sequencing (WGS), multilocus sequence typing (MLST), N.gonorrhoeae multiantigen sequence typing (NG-MAST), and N.gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) were obtained based on the PubMLST database ( https://pubmlst.org/ ). Phylogenetic analysis was used for dissemination and tracking analysis. RESULTS: Antimicrobial susceptibility was performed on 347 isolates, and 50 isolates were identified as decreased susceptibility (DS) to cephalosporins. Of which 16.0% (8/50) were ceftriaxone DS, 38.0% (19/50) were cefixime DS, and 46.0% (23/50) were both ceftriaxone and cefixime DS. In all, the dual-resistant rate of the cephalosporin-DS isolates was 96.0% for penicillin and 98.0% for tetracycline-resistant, and 10.0% (5/50) were resistant to azithromycin. All cephalosporin-DS isolates were resistant to ciprofloxacin but sensitive to spectinomycin. The predominant MLSTs were ST7363 (16%, 8/50), ST1903 (14%, 7/50), ST1901 (12%, 6/50), and ST7365 (10%, 5/50). Besides some isolates that failed genotyping (NA), NG-STAR ST1143 (n = 6) and NG-MAST ST17748 (n = 4) were the most prevalent. Twelve isolates with mosaic penA-60.001 allele retained the most elevated cephalosporin MIC (Minimum Inhibitory Concentration). Phylogenetic analysis revealed that epidemic penA-60.001 clones, either domestic or foreign, had spread to nine cities in Guangdong, and 9/12 clones were from the Pearl River Delta region. CONCLUSIONS: N. gonorrhoeae with cephalosporins-DS was extensively disseminated in Guangdong, Southern China, requiring strict surveillance.

In situ preparation of MOF-199 into the carrageenan-grafted-polyacrylamide@Fe3O4 matrix for enhanced adsorption of levofloxacin and cefixime antibiotics from water.

In this research study, a novel method, an in-situ growth approach, to incorporate metal-organic framework (MOF) into carrageenan-grafted- polyacrylamide-Fe3O4 substrate was introduced. Carrageenan-grafted-polyacrylamide-Fe3O4/MOF nanocomposite (kC-g-PAAm@Fe3O4-MOF-199) was fabricated utilizing three stages. In this way, the polyacrylamide (PAAm) was grafted onto the carrageenan (kC) backbone via free radical polymerization in the presence of methylene bisacrylamide (MBA) as cross-linker and Fe3O4 magnetic nanoparticles. Next, the kC-g-PAAm@Fe3O4 was modified by MOF-199 via an in-situ solvothermal approach. Several analyses such as Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-Dispersive X-ray Spectroscopy (EDX), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET) demonstrated the successful synthesis of kC-g-PAAm@Fe3O4-MOF-199 magnetic hydrogel nanocomposite. The XRD pattern of magnetic hydrogel nanocomposite illustrated characteristic peaks of Fe3O4, neat kC, and MOF-199 with enhanced crystallinity in comparison with kC-g-PAAm@Fe3O4. TGA showed it has a char yield of 24 wt% at 800 °C. VSM confirmed its superparamagnetic behavior (with Ms of 8.04 emu g-1), and the BET surface area of kC-g-PAAm@Fe3O4-MOF-199 was measured at 64.864 m2 g-1, which was higher than that of kC-g-PAAm@Fe3O4 due to the highly porous MOF-199 incorporation with a BET surface area of 905.12 m2 g-1). The adsorption effectiveness of kC-g-PAAm@Fe3O4-MOF-199 for eliminating cephalosporin and quinolones antibiotics, i.e., Cefixime (CFX) and Levofloxacin (LEV) from the aquatic area was considered. Several experimental setups were used to evaluate the efficacy of adsorption, such as solution pH, amount of adsorbent, contact duration, and initial concentration. The maximum adsorption capacity (Qmax) of the prepared magnetic hydrogel nanocomposite was found to be 2000 and 1666.667 mg-1 for LEV and CFX using employing 0.0025 g of adsorbent. The Freundlich isotherm model well described the experimental adsorption data with R2CFX = 0.9986, and R2LEV = 0.9939. And the adsorption kinetic data were successfully represented by the pseudo-second-order model with R2LEV = 0.9949 and R2CFX = 0.9906. Hydrogen bonding, π-π interaction, diffusion, and entrapment in the hydrogel network all contributed to the successful adsorption of both antibiotics onto the kC-g-PAAm@Fe3O4-MOF-199 adsorbent. Other notable physicochemical properties include the three-dimensional structure and availability of the reactive adsorption sites. Moreover, the adsorption/desorption efficacy of magnetic hydrogel nanocomposites was not significantly diminished after four cycles of recovery.