Neisseria gonorrhoeae isolates resistant to extended spectrum cephalosporins and macrolides isolated from symptomatic men in western Kenya.

BACKGROUND: We characterized the antimicrobial resistance (AMR) profiles of Neisseria gonorrhoeae (NG) isolated from symptomatic men at a sexually transmitted infection clinic in Kisumu, Kenya. METHODS: Two urethral swabs were obtained from symptomatic men between 2020 and 2022, one for Gram's stain and the other inoculated directly onto modified Thayer-Martin media containing 1% VCNT and 1% IsoVitaleX enrichment. Culture results were confirmed by colony morphology, Gram's stain and oxidase test. Duplicate isolates were shipped to Uniformed Services University for confirmation and characterization. Susceptibility to eight drugs was assessed by E-test. Agar dilution confirmed resistance to ceftriaxone, cefixime, and azithromycin. Susceptibility, intermediate resistance (IR), and resistance (R) were determined according to published criteria. RESULTS: Of 154 enrolled participants, 112 were culture-positive for NG. Agar dilution results in 110 (98.2%) showed the following: azithromycin-R (1.8%), and 4.5% R or IR to ceftriaxone or cefixime: ceftriaxone-R (0.9%), ceftriaxone-IR (2.7%), and cefixime-IR (2.7%). By E-test, most isolates were IR or R to tetracycline (97.2%), penicillin (90.9%), and ciprofloxacin (95.4%). CONCLUSIONS: We detected NG with resistance to azithromycin and ceftriaxone, indicating a growing threat to the current Kenyan dual syndromic treatment of urethritis with cephalosporin plus macrolides. Ongoing AMR surveillance is essential for effective drug choices.

Susceptibility of Neisseria gonorrhoeae against a dual treatment antibiotics regimen in primary health centres in Surabaya, Indonesia.

BACKGROUND AND OBJECTIVES: There were 82.4 million new gonorrhoea cases worldwide in 2020. Dual treatment with ceftriaxone or cefixime and azithromycin or doxycycline is currently recommended for gonorrhoea in Indonesia. However, reduced susceptibility and resistance to cephalosporins and azithromycin are increasing. We evaluated the susceptibility pattern of Neisseria gonorrhoeae to cefixime, ceftriaxone, azithromycin and doxycycline. METHOD: N. gonorrhoeae isolates were obtained from 19 male participants with clinically and laboratory-confirmed gonorrhoea. Antibiotic susceptibility testing was conducted by disc diffusion and interpreted according to Clinical and Laboratory Standards Institute and Centers for Disease Control and Prevention criteria. RESULTS: Reduced susceptibility or resistance was observed against doxycycline in 19 isolates (100%), cefixime in six (31.6%), ceftriaxone in three (15.8%) and azithromycin in zero (0%) isolates. DISCUSSION: A dual treatment regimen with ceftriaxone and azithromycin can still be recommended as first-line therapy for gonorrhoea in Indonesia. Antibiotic susceptibility surveillance of N. gonorrhoeae should be routinely conducted.

Favourable effect of clavulanic acid on the minimum inhibitory concentrations of cefixime and ceftibuten in ESBL-producing Escherichia coli and Klebsiella pneumoniae.

OBJECTIVES: The use of cephalosporins combined with clavulanate for the treatment of ESBL-harbouring Enterobacteriaceae has been scarcely described. We aimed to describe the effect of different concentrations of clavulanate in the MIC of cefixime and ceftibuten of ESBL-producing Escherichia coli and Klebsiella pneumoniae. METHODS: ESBL-producing E. coli and K. pneumoniae isolates were studied. Fixed concentrations of cefixime and ceftibuten (ranges of 32-0.25 and 64-0.5 ng/ml, respectively) were used. Combinations of cefixime/clavulanate and ceftibuten/clavulanate in different ratios (1:0, 1:1, 2:1, 4:1, 8:1, 16:1, 32:1) were tested. MIC were determined by broth microdilution. RESULTS: A total of 6 ESBL-producing E. coli, 6 ESBL-producing K. pneumoniae and 2 control E. coli were tested. When different quantities of clavulanate were added to cefixime and ceftibuten, greater than two-fold decreases in the MIC were observed. When testing the 1:1 cefixime/clavulanate ratio, 10/12 isolates were susceptible. When the ratios 2:1, 4:1, 8:1 and 16:1 were tested, susceptibility was noted for 9/12, 8/12, 4/12 and 5/12 isolates, respectively. Only 2/12 K. pneumoniae isolates were susceptible when the ratio 32:1 was tested. When testing ceftibuten/clavulanate, all isolates remained susceptible across all experiments. CONCLUSIONS: Clavulanic acid has a favourable effect in reducing the MIC of cefixime and ceftibuten in isolates of ESBL-producing E. coli and K. pneumoniae. Combining clavulanate with ceftibuten or cefixime could be a useful treatment strategy.

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.

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.

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.

Phenotypic and genotypic characterization of Neisseria gonorrhoeae isolates among individuals at high risk for sexually transmitted diseases in Zurich, Switzerland.

BACKGROUND: While ceftriaxone resistance remains scarce in Switzerland, global Neisseria gonorrhoeae (NG) antimicrobial resistance poses an urgent threat. This study describes clinical characteristics in MSM (men who have sex with men) diagnosed with NG infection and analyses NG resistance by phenotypic and genotypic means. METHODS: Data of MSM enrolled in three clinical cohorts with a positive polymerase chain reaction test (PCR) for NG were analysed between January 2019 and December 2021 and linked with antibiotic susceptibility testing. Bacterial isolates were subjected to whole genome sequencing (WGS). RESULTS: Of 142 participants, 141 (99%) were MSM and 118 (84%) living with HIV. Participants were treated with ceftriaxone (N = 79), azithromycin (N = 2), or a combination of both (N = 61). No clinical or microbiological failures were observed. From 182 positive PCR samples taken, 23 were available for detailed analysis. Based on minimal inhibitory concentrations (MICs), all isolates were susceptible to ceftriaxone, gentamicin, cefixime, cefpodoxime, ertapenem, zoliflodacin, and spectinomycin. Resistance to azithromycin, tetracyclines and ciprofloxacin was observed in 10 (43%), 23 (100%) and 11 (48%) of the cases, respectively. Analysis of WGS data revealed combinations of resistance determinants that matched with the corresponding phenotypic resistance pattern of each isolate. CONCLUSION: Among the MSM diagnosed with NG mainly acquired in Switzerland, ceftriaxone MICs were low for a subset of bacterial isolates studied and no treatment failures were observed. For azithromycin, high occurrences of in vitro resistance were found. Gentamicin, cefixime, cefpodoxime, ertapenem, spectinomycin, and zoliflodacin displayed excellent in vitro activity against the 23 isolates underscoring their potential as alternative agents to ceftriaxone.

penA profile of Neisseria gonorrhoeae in Guangdong, China: Novel penA alleles are related to decreased susceptibility to ceftriaxone or cefixime.

BACKGROUND: Resistance to extended-spectrum cephalosporins (ESCs) has become a public health concern with the spread of Neisseria gonorrhoeae and increasing antimicrobial resistance. Mutation of penA, encoding penicillin-binding protein 2, represents a mechanism of ESC resistance. This study sought to assess penA alleles and mutations associated with decreased susceptibility (DS) to ESCs in N. gonorrhoeae. MATERIALS AND METHODS: In 2021, 347 gonococci were collected in Guangdong, China. Minimum inhibitory concentations (MICs) of ceftriaxone and cefixime were determined, and whole-genome sequencing and phylogenetic analysis were performed. Multi-locus sequence typing (MLST) and conventional resistance determinants such as penA, mtrR, PonA and PorB were analysed. penA was genotyped and sequence-aligned using PubMLST. RESULTS: Genome-wide phylogenetic analysis revealed that the prevalence of DS to ESCs was highest in Clade 11.1 (100.0%), Clade 2 (66.7%) and Clade 0 (55.7%), and the leading cause was strains with penA-60.001 or new penA alleles in clades. The penA phylogenetic tree is divided into two branches: non-mosaic penA and mosaic penA. The latter contained penA-60.001, penA-10 and penA-34. penA profile analysis indicated that A311V and T483S are closely related to DS to ESCs in mosaic penA. The new alleles NEIS1753_2840 and NEIS1753_2837 are closely related to penA-60.001, with DS to ceftriaxone and cefixime of 100%. NEIS1753_2660, a derivative of penA-10 (A486V), has increased DS to ceftriaxone. NEIS1753_2846, a derivative of penA-34.007 (G546S), has increased DS to cefixime. CONCLUSION: This study identified critical penA alleles related to elevated MICs, and trends of gonococcus-evolved mutated penA associated with DS to ESCs in Guangdong.

Affinity of ß-Lactam Antibiotics for Neisseria gonorrhoeae Penicillin-Binding Protein 2 Having Wild, Cefixime-Reduced-Susceptible, and Cephalosporin (Ceftriaxone)-Resistant penA Alleles.

Multidrug-resistant Neisseria gonorrhoeae is a serious concern worldwide. Resistance to ß-lactam antibiotics occurs through mutations in penicillin-binding proteins (PBPs), acquisition of ß-lactamases, and alteration of antibiotic penetration. Mosaic structures of penA, which encodes PBP2, play a major role in resistance to ß-lactams, especially cephalosporins. Ceftriaxone (CRO) is recognized as the only satisfiable antibiotic for the treatment of gonococcal infections; however, CRO-resistant isolates have emerged in the community. Here, we examined the affinity of ß-lactam antibiotics for recombinant PBP2 in a competition assay using fluorescence-labeled penicillin. We found no or little difference in the affinities of penicillins and meropenem (MEM) for PBP2 from cefixime (CFM)-reduced-susceptible strain and cephalosporin-resistant strain. However, the affinity of cephalosporins, including CRO, for PBP2 from the cephalosporin-resistant strain was markedly lower than that for PBP2 from the CFM-reduced-susceptible-resistant strain. Notably, piperacillin (PIP) showed almost the same affinity for PBP2 from penicillin-susceptible, CFM-reduced-susceptible, and cephalosporin (including CRO)-resistant strains. Thus, PIP/tazobactam and MEM are candidate antibiotics for the treatment of CRO-resistant/multidrug-resistant N. gonorrhoeae.

Antibiotic susceptibility and genotypic characterization of Neisseria gonorrhoeae isolates in the Comunidad Valenciana (Spain): GONOvig project.

INTRODUCTION: The increase in sexually transmitted infections (STI) caused by Neisseria gonorrhoeae (NG) worldwide, together with the decrease in antibiotic susceptibility, forced us to understand the epidemiology of gonococcal infection. METHODS: The GONOvig project analyzed, comparatively following CLSI and EUCAST criteria, the antibiotic susceptibility of 227 NG strains collected in thirteen representative hospitals of the Valencia Community (CV) between 2013 and 2018. Additionally, molecular typing of 175 strains using the NG multi-antigen sequence typing technique (NG-MAST) was performed. RESULTS: High rates of resistance to tetracycline (38.2% by CLSI and 50.9% by EUCAST) and ciprofloxacin (49.1% CLSI and 54% EUCAST), and low percentages of resistance to spectinomycin (0%), cefixime (0.5% CLSI but 5.9% EUCAST), and ceftriaxone (1.5% CLSI and 2.4% EUCAST) were detected. Azithromycin resistance was 6% (both CLSI and EUCAST). Molecular analysis revealed the presence of 86 different sequence types (ST), highlighting ST2992 (7.4%), ST3378 (6.9%), ST2400 (4.6%) and ST13288 (6.9%), which was associated with resistance to cefixime (P=.031). The main genogroups (G) were G1407 (13.1%), G2992 (10.3%), G2400 (6.3%) and G387 (3.4%). G1407 and G2400 were associated with resistance to ciprofloxacin (P<.03). CONCLUSION: Low resistance to ceftriaxone, a worrying resistance to azithromycin and a wide variety of circulating sequence types have been detected, some of which show correlation with certain resistance profiles.

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.

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.

Correlates of Neisseria gonorrhoeae antimicrobial resistance: cross-sectional results from an open cohort sentinel surveillance network in Québec, Canada, 2016-2019.

OBJECTIVES: To examine correlates of Neisseria gonorrhoeae antimicrobial resistance (AMR) to first-line antimicrobials (azithromycin, cefixime and ceftriaxone). DESIGN AND SETTING: The sentinel surveillance network is an open cohort of gonococcal infection cases from Québec, Canada. Cross-sectional results are reported herein. PARTICIPANTS: Between 1 January 2016 and 31 December 2019, data from 886 individuals accounting for 941 gonorrhoea cases were included. METHODS: Epidemiological and clinical data were collected using an auto-administered questionnaire, direct case interviews and chart reviews. Antimicrobial susceptibility testing was performed using the agar dilution method. Generalised estimating equations were used for regression. RESULTS: The prevalence of azithromycin resistance with a minimal inhibitory concentration (MIC) of ≥2 mg/L was 21.3%. In 2016, men who have sex with men were more likely to be infected with an azithromycin-resistant N. gonorrhoeae isolate (adjusted prevalence ratio (aPR)=4.73, 95% CI 1.48 to 15.19) or with an isolate with increased third-generation cephalosporin (3GC) MIC (aPR=5.32, 95% CI 1.17 to 24.11 for cefixime (MIC≥0.06 mg/L) and aPR=4.38, 95% CI 1.53 to 12.54 for ceftriaxone (MIC≥0.03 mg/L)). However, these associations were not maintained between 2017 and 2019, with increased MIC observed in men who have sex exclusively with women and women. Overall, azithromycin resistance was significantly more likely in cases who self-reported HIV infection (aPR=1.65, 95% CI 1.00 to 2.71). Cefixime increased MIC were more likely in individuals 25-34 years old (aPR=2.23, 95% CI 1.18 to 4.21). Cefixime and ceftriaxone increased MIC were both more likely in cases who reported ≥5 sexual partners (cefixime: aPR=2.10, 95% CI 1.34 to 3.27 and ceftriaxone: aPR=1.62, 95% CI 1.14 to 2.30). CONCLUSION: Significant correlates of N. gonorrhoeae AMR to first-line antimicrobials were observed. Antimicrobial stewardship may be particularly important for 3GC. Active monitoring and interventions are critical for 3GC non-susceptible strains, especially considering the very low prevalence in Québec.

The third nationwide surveillance of antimicrobial susceptibility against Neisseria gonorrhoeae from male urethritis in Japan, 2016-2017.

Neisseria gonorrhoeae is one of the important pathogens of sexually transmitted infections. N. gonorrhoeae is rapidly becoming antimicrobial resistant, and there are few drugs that are effective in the initial treatment of gonorrhea. To understand the trends of antimicrobial susceptibility of N. gonorrhoeae, the Surveillance Committee of the Japanese Society of Infectious Diseases, the Japanese Society for Chemotherapy, and the Japanese Society of Clinical Microbiology conducted the third nationwide antimicrobial susceptibility surveillance of N. gonorrhoeae isolated from male urethritis. The specimens were collected from male patients with urethritis at 30 facilities from May 2016 to July 2017. From the 159 specimens collected, 87 N. gonorrhoeae strains were isolated, and 85 were tested for susceptibility to 21 antimicrobial agents. All strains were non-susceptible to penicillin G. Seven strains (8.2%) were ß-lactamase-producing strains. The rates of susceptibility to cefixime and cefpodoxime were 96.5% and 52.9%, respectively. Three strains were non-susceptible with a minimum inhibitory concentration (MIC) of 0.5 mg/L for cefixime. None of the strains were resistant to ceftriaxone or spectinomycin. The susceptibility rate for ciprofloxacin was 23.5% (20 strains), and no strains showed intermediate susceptibility. The susceptibility rate against azithromycin was 81.2%, with one strain isolated with a MIC of 8 mg/L against azithromycin. The results of this surveillance indicate that ceftriaxone and spectinomycin, which are currently recommended for gonococcal infections in Japan, appear to be effective. It will be necessary to further expand the scale of the next surveillance to understand the current status of drug-resistant N. gonorrhoeae in Japan.

Antibiotic resistance profile of Helicobacter pylori to 14 antibiotics: a multicenter study in Fujian, China.

Background and aim: Efficacy of Helicobacter pylori (H. pylori) eradication is related to the local antimicrobial resistance epidemiology. We aimed to investigate the antibiotic resistance of H. pylori in Fujian, China. Methods: H. pylori-infected patients in four centers were enrolled in the study from Oct 2019 to Jan 2022. The bacteria were isolated, cultured and identified from the biopsy of patients' gastric mucosa samples. Antimicrobial susceptibility testing was performed by a modified broth microdilution method for H. pylori to seven guideline-recommended antibiotics and seven potential choices for H. pylori eradication. Results: A total of 205 H. pylori strains were isolated. The resistance rates of amoxicillin (AMX), amoxicillin and clavulanate potassium (AMC), cefixime (CFM), gentamicin (GEN), tetracycline (TET), doxycycline (DOX), azithromycin (AZM), clarithromycin (CLR), levofloxacin (LVFX), sparfloxacin (SPFX), metronidazole (MTZ), tinidazole (TID), rifampicin (RFP) and furazolidone (FZD) were 11.22%, 12.20%, 7.32%, 12.20%, 4.88%, 4.39%, 44.39%, 43.90%, 30.24%, 21.46%, 40.98%, 45.85%, 5.37% and 10.24%, respectively. The rates of pan-sensitivity, single, double, triple and multiple resistance for seven guideline-recommended antibiotics were 32.68%, 30.24%, 13.17%, 7.76%, and 14.15%, respectively. The main double-resistance patterns were CLR+MTZ (10/205, 5%) and CLR+LVFX (9/205, 4%). The main triple-resistance pattern was CLR+MTZ+ LVFX (15/205, 7%). Conclusions: In Fujian, the prevalence of H. pylori resistance to AZM, CLR, LVFX, SPFX, MTZ, and TID was high, whereas that to AMX, AMC, GEN, CFM, TET, DOX, RFP and FZD was relatively low. CFM and DOX are promising new choices for H. pylori eradication.

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.

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.

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.

Emergence of a predominant sequence type ST7363 and the increasing trend of resistance to cefixime and ceftriaxone in Neisseria gonorrhoeae in Southern Taiwan, 2019-2021.

BACKGROUND/PURPOSE: Multi-drug resistance and the presence of epidemic lineages of Neisseria gonorrhoeae locally and globally were important clinical and public health issues. We aimed to investigate the molecular epidemiology and the antimicrobial susceptibility profiles of N. gonorrhoeae in Southern Taiwan. METHODS: Between 2019 and 2021, adult patients who had suspected gonorrhea and attended a urology clinic in southern Taiwan were recruited to participate in this study. Clinical data from medical records and a questionnaire, antimicrobial susceptibility testing using a disk diffusion test in accordance with the guidelines by the Clinical and Laboratory Standards Institute, and Multi-locus sequence typing (MLST) were analyzed. RESULTS: A total of 500 patients participated in the surveillance study. Among them, 232 N. gonorrhoeae isolates were identified, but only 164 isolates were recovered for further research. ST7363 (n = 83, 50.61%) was found to be the predominant sequence type, followed by ST1583 (n = 24, 14.63%), ST1588 (n = 13, 7.93%), and ST7827 (n = 12, 7.32%). 100% resistance to penicillin and 99.4% non-susceptible rate of ciprofloxacin were observed. The azithromycin resistant rate being 15.24% and the cefixime non-susceptible rate being 17.07% were alarming, both with decreasing trends in susceptibilities during 2019-2021. The 25 azithromycin resistant isolates were mainly belonged to ST7363 (n = 12) and ST7827 (n = 3). Seven (4.2%) isolates were ceftriaxone non-susceptible. Among them, four were assigned to be ST 7827 and three belonged to ST7363. CONCLUSION: We observed the emergence of a predominant sequence type ST7363 in southern Taiwan. Compared with previous Taiwan studies, the increasing trend of resistance to cefixime and ceftriaxone necessitates clinicians' alertness for clinical treatment response of the extended spectrum cephalosporins and the further surveillance monitor.

Frequency and Antibiotics Sensitivity Pattern of Culture-Positive Salmonella Typhi in Children.

OBJECTIVE: To calculate the frequency of positive blood culture in clinically diagnosed cases of enteric fever and antibiotic sensitivity patterns in culture-positive cases of S.typhi Study Design: Observational Study. Place and Duration of the Study: Department of Paediatrics Medicine, Services Hospital Lahore, from November 15th 2020 to May 15th 2021. METHODOLOGY: A total of 246 patients, fulfilling the definition of a suspected case of enteric fever were enrolled. Blood cultures were drawn on the spot. Antimicrobial sensitivity for 8 antimicrobial agents-Ampicillin, amoxicillin, chloramphenicol, cefixime, ceftriaxone, cefotaxime, ciprofloxacin, meropenem, and Azithromycin, were performed. A p-value of <0.05 was considered statistically significant. RESULTS: Blood cultures were positive in 62 (25.2%), patients out of which 34 (54.9%) were females and 28 (45.1%) were males, of which, 58 were S. typhi and 4 were S. Paratyphi A or B. Cefixime was sensitive in 27.4% of patients and intermediate sensitivity was found in 3.2% of cases and 69.4% of cases were resistant, ceftriaxone was sensitive in 38.7% of cases and Azithromycin was sensitive in 96.7% of cases, whereas meropenem showed 100% sensitivity. Chloramphenicol and Ciprofloxacin were resistant in 80.6% and 27.3% of the cases respectively. Among isolates, 32.3% (20) were categorised as sensitive enteric fever; 64.5% (40) as MDR, and 3.2% (2) as XDR enteric fever. CONCLUSION: MDR and XDR enteric fever are a major concern. For such cases, Azithromycin remains the best oral antibiotic with a sensitivity of up to 96.7%. Meropenem was sensitive in 100% of cases and was the only antibiotic with no documented resistance in this study. KEY WORDS: Enteric fever, Salmonella, Antibiotic sensitivity, Blood culture, MDR, XDR, Azithromycin, Meropenem.