Fundamental and Second-Order Superregular Breathers in Vector Fields.

We developed an exact theory of the superregular breathers (SRBs) of Manakov equations. We have shown that the vector SRBs do exist both in the cases of focusing and defocusing Manakov systems. The theory is based on the eigenvalue analysis and on finding the exact links between the SRBs and modulation instability. We have shown that in the focusing case the localized periodic initial modulation of the plane wave may excite both a single SRB and the second-order SRBs involving four fundamental breathers.

Ceftriaxone-Resistant Gonorrhea - China, 2022.

Gonorrhea is a widespread sexually transmitted infection; in 2022, China reported 96,313 cases of gonorrhea, making it the fourth most common notifiable infectious disease in the country after viral hepatitis, pulmonary tuberculosis, and syphilis. The rise in prevalence in antimicrobial-resistant strains, particularly the international spread of ceftriaxone-resistant clones, poses a formidable challenge to gonorrhea control. The China Gonococcal Resistance Surveillance Program (China-GRSP), established in 1987 and covering 19 of 34 provincial-level administrative units, continuously monitors gonococcal antimicrobial resistance. In 2022, 13 China-GRSP sentinel sites collected 2,804 gonococcal isolates, representing 2.9% of all cases reported in China, and 4.1% of cases reported in the 13 participating provinces. The prevalence of Neisseria gonorrhoeae resistance to ceftriaxone was 8.1%, approximately three times the 2017 rate of 2.9%; five provinces reported >10% ceftriaxone resistance. Resistance prevalences to cefixime, azithromycin, tetracycline, penicillin, and ciprofloxacin were 16.0%, 16.9%, 77.1%, 77.8%, and 97.6%, respectively. Only one case of spectinomycin resistance was reported. These data highlight a substantial increase in ceftriaxone resistance from 2017 to 2022. Effective diagnosis and treatment and appropriate management of sex partners are essential to protect the health of infected persons and prevent ongoing transmission of gonorrhea, including transmission of resistant strains. Identifying reasons for the spread of ceftriaxone-resistant N. gonorrhoeae in China could guide strategies, such as antibiotic stewardship, to mitigate the rising resistance rate and curb the spread of resistant strains.

A Nationwide Survey on Detection of Chlamydia trachomatis in Health Facilities in China.

BACKGROUND: This study evaluated the clinical laboratory capacity for the diagnosis of Chlamydia trachomatis (CT) in China to provide recommendations to improve the diagnostic capacity and quality of this clinically important sexually transmitted disease. METHODS: An electronic questionnaire-based cross-sectional, survey study was conducted by the National Center for STD Control among different types of healthcare facilities in China from July to December 2021. RESULTS: The surveyed laboratory facilities were located in 332 cities in 31 provinces in China. A total of 4640 records from clinical laboratories were included in the data set for the final analysis. Less than half of the laboratories (41.6% [1931 of 4640]) performed the CT diagnostic test; of these, 721 laboratories (15.5% [721 of 4640]) carried out nucleic acid amplification test (NAAT) methods, and 1318 laboratories (28.4% [1318 of 4640]) performed antigen-based immunochromatographic assays. Most laboratories were equipped with biological safety cabinets (93.7% [4348 of 4640]), 49.2% (2283 of 4640) were equipped with fully automated nucleic acid extractors, and 55.2% (2560 of 4640) were equipped with polymerase chain reaction amplification instruments. The laboratories from Southern China or third-class hospitals (i.e., the highest rated hospitals) had the highest proportion using NAATs to diagnose CT among the surveyed health facilities. CONCLUSIONS: Advancing laboratories to use NAAT to detect CT should be phased step-by-step by different areas and levels of hospitals according to the current situation.

A Single Amino Acid Substitution in Elongation Factor G Can Confer Low-Level Gentamicin Resistance in Neisseria gonorrhoeae.

The continued emergence of Neisseria gonorrhoeae isolates which are resistant to first-line antibiotics has reinvigorated interest in alternative therapies such as expanded use of gentamicin (Gen). We hypothesized that expanded use of Gen promotes emergence of gonococci with clinical resistance to this aminoglycoside. To understand how decreased susceptibility of gonococci to Gen might develop, we selected spontaneous low-level Gen-resistant (GenR) mutants (Gen MIC = 32 µg/mL) of the Gen-susceptible strain FA19. Consequently, we identified a novel missense mutation in fusA, which encodes elongation factor G (EF-G), causing an alanine (A) to valine (V) substitution at amino acid position 563 in domain IV of EF-G; the mutant allele was termed fusA2. Transformation analysis showed that fusA2 could increase the Gen MIC by 4-fold. While possession of fusA2 did not impair either in vitro gonococcal growth or protein synthesis, it did result in a fitness defect during experimental infection of the lower genital tract in female mice. Through bioinformatic analysis of whole-genome sequences of 10,634 international gonococcal clinical isolates, other fusA alleles were frequently detected, but genetic studies revealed that they could not decrease Gen susceptibility in a similar manner to fusA2. In contrast to these diverse international fusA alleles, the fusA2-encoded A563V substitution was detected in only a single gonococcal clinical isolate. We hypothesize that the rare occurrence of fusA2 in N. gonorrhoeae clinical isolates is likely due to a fitness cost during infection, but compensatory mutations which alleviate this fitness cost could emerge and promote GenR in global strains.

Treatment Combining Focused Ultrasound with Gastrodin Alleviates Memory Deficit and Neuropathology in an Alzheimer's Disease-Like Experimental Mouse Model.

Alzheimer's disease (AD) is the most common type of dementia but lacks effective treatment at present. Gastrodin (GAS) is a phenolic glycoside extracted from the traditional Chinese herb-Gastrodia elata-and has been reported as a potential therapeutic agent for AD. However, its efficiency is reduced for AD patients due to its limited BBB permeability. Studies have demonstrated the feasibility of opening the blood-brain barrier (BBB) via focused ultrasound (FUS) to overcome the obstacles preventing medicines from blood flow into the brain tissue. We explored the therapeutic potential of FUS-mediated BBB opening combined with GAS in an AD-like mouse model induced by unilateral intracerebroventricular (ICV) injection of Aß 1-42. Mice were divided into 5 groups: control, untreated, GAS, FUS and FUS+GAS. Combined treatment (FUS+GAS) rather than single intervention (GAS or FUS) alleviated memory deficit and neuropathology of AD-like mice. The time that mice spent in the novel arm was prolonged in the Y-maze test after 15-day intervention, and the waste-cleaning effect was remarkably increased. Contents of Aß, tau, and P-tau in the observed (also the targeted) hippocampus were reduced. BDNF, synaptophysin (SYN), and PSD-95 were upregulated in the combined group. Overall, our results demonstrate that FUS-mediated BBB opening combined with GAS injection exerts the potential to alleviate memory deficit and neuropathology in the AD-like experimental mouse model, which may be a novel strategy for AD treatment.

Low-Intensity Focused Ultrasound Alleviates Chronic Neuropathic Pain-Induced Allodynia by Inhibiting Neuroplasticity in the Anterior Cingulate Cortex.

Low-intensity focused ultrasound (LIFU) is a potential noninvasive method to alleviate allodynia by modulating the central nervous system. However, the underlying analgesic mechanisms remain unexplored. Here, we assessed how LIFU at the anterior cingulate cortex (ACC) affects behavior response and central plasticity resulting from chronic constrictive injury (CCI). The safety of LIFU stimulation was assessed by hematoxylin and eosin (H&E) and Fluoro-Jade C (FJC) staining. A 21-day ultrasound exposure therapy was conducted from day 91 after CCI surgery in mice. We assessed the 50% mechanical withdrawal threshold (MWT50) using Von Frey filaments (VFFs). The expression levels of microtubule-associated protein 2 (MAP2), growth-associated protein 43 (GAP43), and tau were determined via western blotting (WB) and immunofluorescence (IF) staining to evaluate the central plasticity in ACC. The regions of ACC were activated effectively and safely by LIFU stimulation, which significantly increased the number of c-fos-positive cells (P < 0.05) with no bleeding, coagulative necrosis, and neuronal loss. Under chronic neuropathic pain- (CNP-) induced allodynia, MWT50 decreased significantly (P < 0.05), and overexpression of MAP2, GAP43, and tau was also observed. After 3 weeks of treatment, significant increases in MWT50 were found in the CCI+LIFU group compared with the CCI group (P < 0.05). WB and IF staining both demonstrated a significant reduction in the expression levels of MAP2, GAP43, and tau (P < 0.05). LIFU treatment on ACC can effectively attenuate CNP-evoked mechanical sensitivity to pain and reverse aberrant central plasticity.

Exact Analytic Spectra of Asymmetric Modulation Instability in Systems with Self-Steepening Effect.

Nonlinear waves become asymmetric when asymmetric physical effects are present within the system. One example is the self-steepening effect. When exactly balanced with dispersion, it leads to a fully integrable system governed by the Chen-Lee-Liu equation. The latter provides a natural basis for the analysis of asymmetric wave dynamics just as nonlinear Schrödinger or Korteweg-de Vries equations provide the basis for analyzing solitons with symmetric profile. In this work, we found periodic wave trains of the Chen-Lee-Liu equation evolved from fully developed modulation instability and analyzed a highly nontrivial spectral evolution of such waves in analytic form that shows strong asymmetry of its components. We present the conceptual basis for finding such spectra that can be used in analyzing asymmetric nonlinear waves in other systems.

Efficacy of gabexate mesilate in preventing post endoscopic retrograde cholangiopancreatography pancreatitis: A meta-analysis of randomized clinical trials.

BACKGROUND/PURPOSE: The evidence provided by syntheses of the preventative effects of gabexate mesilate against pancreatitis among patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) is limited and highly heterogeneous. To enhance the understanding of this topic, this study aimed to provide overview of gabexate mesilate on preventing post ERCP pancreatitis (PEP) by synthesizing all relevant randomized controlled trials (RCTs). METHODS: We searched three databases for relevant RCTs. Two authors independently extracted data of pancreatitis incidence after ERCP, abdominal pain within 48 hours, and hyperamylasemia for quality assessment and meta-analysis. RESULTS: Thirteen RCTs with 3718 patients undergoing ERCP met the eligibility criteria and were included. The results revealed that the use of gabexate mesilate led to lower PEP (Peto odds ratio: 0.66, 95% confidence interval [CI]: 0.49 to 0.89), especially in the subgroup of gabexate mesilate infusion starting more than 30 min (Risk ratio: 0.45, 95% CI: 0.29 to 0.72). CONCLUSION: The present synthesis found that gabexate mesilate could be an option of prophylactic treatment of pancreatitis for patients undergoing ERCP, and reveals that it is favorable to administer it starting 30 min before the ERCP. This evidence may improve the clinical prevention of PEP.

The Anatomy of the Temporal and Zygomatic Branches of the Facial Nerve: Application to Crow's Feet Wrinkles.

BACKGROUND: Advances in the understanding of wrinkling crow's feet while improving the safety and efficacy of botulinum toxin type A injection has pointed to drug dispersion in the lateral orbital wrinkles as a cause of adverse events of botulinum toxin type A injection. The purpose of this study is to identify the distribution of temporal and zygomatic branches of facial nerve in the orbicularis oculi muscles. METHODS: Anatomical dissection of cadavers was performed in 31 cadavers, 13 females and 18 males, with ages ranging from 20 to 60 years, which of all had been embalmed by 10% formalin solution. The facial nerve was identified within subcutaneous tissue close periorbital region and both traced proximal and distal. Its temporal branch, zygomatic branch, facial and muscular entrance were located and accurately measured relative to established surface landmarks. RESULTS: Dissection of the facial nerve revealed 2 to 6 entrances of the temporal branch into the orbicularis oculi and 1 to 5 entrances of the zygomatic branch into the orbicularis oculi. Concerning the measurements of neural entering points, distance and angle from orbicularis oculi muscle to lateral ocular angle, a distribution map of its muscular entrance and their patterns of distribution were constructed. According to the dense area of the coordinate map, there were 3 points determined as the muscular entrance points to established surface landmarks. CONCLUSIONS: An anatomical dissection of cadavers was performed to identify the distribution of temporal and zygomatic branches of the facial nerve in the orbicularis oculi. According to the dense area of the coordinate map, the surface landmarks of 3 points were established as the muscular entrance of the facial nerve (MEF).

Widespread Use of High-dose Ceftriaxone Therapy for Uncomplicated Gonorrhea Without Reported Ceftriaxone Treatment Failure: Results From 5 Years of Multicenter Surveillance Data in China.

BACKGROUND: Antimicrobial resistance to Neisseria gonorrhoeae has emerged for each of the antibiotics recommended as first-line therapies following their introduction into clinical practice. To improve rational and effective clinical antibiotic treatment, we analyzed the prescription patterns of antibiotics and their therapeutic effect in the treatment of uncomplicated gonorrhea in China. METHODS: We obtained data from a follow-up multicenter surveillance program. Multinomial logistic regression analyses were conducted to explore the associations between demographic/clinical variables with the levels of sensitivity to ceftriaxone and prescription of high-dose ceftriaxone. RESULTS: In this study, 1686 patients infected with N. gonorrhoeae were recruited in a surveillance network during 1 January 2013 through 31 December 2017 in 7 hospitals distributed in 5 provinces. The prevalence of isolates with decreased susceptibility to ceftriaxone was 9.8% (131/1333), fluctuating between 5.6% and 12.1%. Injectable ceftriaxone was chosen as the first-line treatment among 83.1% of patients, and most of them (72.7% [1018/1401]) received >1000 mg dosage. Patients who were previously infected with gonorrhea or other sexually transmitted infections (adjusted odds ratio [AOR], 1.618 [95% confidence interval {CI}, 1.11-2.358]; AOR, 2.08 [95% CI, 1.41-3.069]) or who already used antibiotics for this infection (AOR, 1.599 [95% CI, 1.041-2.454]) were associated with a higher prescribed ceftriaxone dosage. All of the patients recruited in this study were cured regardless of the isolates' susceptibility to ceftriaxone or the dosage of ceftriaxone they received. CONCLUSIONS: No ceftriaxone treatment failure for uncomplicated gonorrhea was reported in China; however, high-dose ceftriaxone was widely used in China. Its impacts need further study.

Sustained transmission of the ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone in China.

BACKGROUND: Ceftriaxone resistance in Neisseria gonorrhoeae has become an imminent threat to effective control of gonorrhoea globally. In recent years, the ceftriaxone-resistant FC428 clone has shown international dissemination. After our first report of the FC428 clone in China in 2016, we now describe another six cases of FC428-related ceftriaxone-resistant N. gonorrhoeae isolates from 2017 and 2018. OBJECTIVES: To identify the phenotypic and molecular characteristics of newly reported ceftriaxone-resistant isolates in China and to investigate the relationship between these isolates and FC428 clones reported globally. METHODS: Antimicrobial susceptibility to ceftriaxone, cefixime, azithromycin, spectinomycin, penicillin, ciprofloxacin and tetracycline was determined by the agar dilution method. N. gonorrhoeae multi-antigen sequence typing (NG-MAST), MLST and N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR) were performed for genotyping and SNPs extracted from whole-genome sequences were used for phylogenetic analysis. RESULTS: All isolates were resistant to ceftriaxone, cefixime, penicillin, tetracycline and ciprofloxacin, but were susceptible to azithromycin and spectinomycin. NG-MAST, MLST and NG-STAR genotyping showed that all isolates shared identical or similar STs (<10 bp difference) to FC428 (NG-MAST ST3435, MLST ST1903, NG-STAR ST233) and contained the same mosaic penA allele 60.001. Phylogenetic analysis showed the Chinese isolates spreading in the whole phylogenetic tree and fully mixed with other international isolates. Half of the Chinese isolates were more closely related (<100 SNPs) to Japanese isolates than other international isolates. CONCLUSIONS: The newly reported cases in China were related to the internationally spreading FC428 clone. These isolates might have played a central role in international transmission of the FC428 clone. High ceftriaxone doses (1-2 g) still provide effective therapy.

Identification of Internationally Disseminated Ceftriaxone-Resistant Neisseria gonorrhoeae Strain FC428, China.

In 2016, we identified a ceftriaxone-resistant Neisseria gonorrhoeae isolate in China. The strain genotype was identical to the resistant clone FC428 that originated in Japan. Enhanced international collaborative surveillance programs are crucial to track the transmission of the ceftriaxone-resistant clones.

An Anatomic Study of the Keyhole Supra-Tentorium to Infra-Tentorium Endoscope Approach.

To provide anatomic basis for the retrosigmoid supra-tentorium to infra-tentorium keyhole approach and to explore the feasibility, 60 skulls were observed and measured to demonstrate the position relations among related bony landmarks, 12 cadaveric heads were dissected and measured for localization of the keyhole and the incision through tentorium. For giving the angle and depth for endoscopic approach, 40 adult volunteers were performed head MRI scan and the pictures were measured and analyzed. The surface projection of sigmoid and transverse sinus can be positioned by mastoidale, external occipital protuberance, and anterior end of parietomastoid suture (AEPMS) on body. There is a safe trigone of cerebellar tentorium (STCT) among inner edge of upper curve of sigmoid sinus, entrance of tentorial sinus/vein and midpoint of posterior edge of temporal arcuate eminence. 15 mm superior to the midpoint between asterion and AEPMS can be recognized as the central point of the keyhole. Magnetic resonance imaging pictures show there is potential subarachnoid space for endoscopic approach from the indicated keyhole to pontocerebellar trigone. This study demonstrated endoscopy can arrive at pontocerebellar trigone through the STCT and the keyhole supra-tentorium to infra-tentorium endoscope approach is feasible in anatomy and will contribute to excise lesions involving both supra- and infra-tentorial structures.

Cephalosporin-Resistant Neisseria gonorrhoeae Clone, China.

Cephalosporin-resistant Neisseria gonorrhoeae is a major public health concern. N. gonorrhoeae of multiantigen sequence type G1407 and multilocus sequence type 1901 is an internationally spreading cephalosporin-resistant clone. We detected 4 cases of infection with this clone in China and analyzed resistance determinants by using N. gonorrhoeae sequence typing for antimicrobial resistance.

Susceptibility of Neisseria gonorrhoeae to azithromycin and ceftriaxone in China: A retrospective study of national surveillance data from 2013 to 2016.

BACKGROUND: Gonorrhea remains one of the most common sexually transmitted diseases worldwide. Successful treatment has been hampered by emerging resistance to each of the antibiotics recommended as first-line therapies. We retrospectively analyzed the susceptibility of gonorrhea to azithromycin and ceftriaxone using data from the China Gonococcal Resistance Surveillance Programme (China-GRSP) in order to provide evidence for updating the treatment recommendations in China. METHODS AND FINDINGS: In this study, we included 3,849 isolates collected from patients with a confirmed positive Neisseria gonorrhoeae (N. gonorrhoeae) culture at clinic visits during the period of 1 January 2013 through 31 December 2016 in 7 provinces. Antimicrobial susceptibility testing of gonorrhea isolates using agar dilution was conducted to determine minimum inhibitory concentration (MIC). Resistance to azithromycin (RTA) was defined as MIC ≥ 1.0 mg/l, and decreased susceptibility to ceftriaxone (DSC) was defined as MIC ≥ 0.125 mg/l. The prevalence of isolates with RTA was 18.6% (710/3,827; 95% CI 17.4%-19.8%). The percentage of patients with DSC fluctuated between 9.7% and 12.2% over this period. The overall prevalence of isolates with both RTA and DSC was 2.3% (87/3,827; 95% CI 1.9%-2.8%) and it increased from 1.9% in 2013 to 3.3% in 2016 (chi-squared test for trend, P = 0.03). Study limitations include the retrospective study design and potential biases in the sample, which may overrepresent men with symptomatic infection, coastal residents, and people reporting as heterosexual. CONCLUSIONS: To our knowledge, this is the first national study on susceptibility of N. gonorrhoeae to azithromycin and ceftriaxone in China. Our findings indicate high rates of RTA and DSC from 2013 to 2016. Although dual therapy with azithromycin and ceftriaxone has been recommended by WHO and many countries to treat gonorrhea, reevaluation of this therapy is needed prior to its introduction in China.

Antimicrobial Susceptibility Evaluation and Multiple-Locus Variable Number Tandem Repeat Analysis of Neisseria gonorrhoeae Isolates in China in 2012.

OBJECTIVE: This study aimed to gain information on the antimicrobial susceptibility and molecular epidemiological typing of Neisseria gonorrhoeae (NG) isolates in China in 2012. METHODS: A total of 244 NG isolates were consecutively recovered from patients with uncomplicated gonorrhea attending sexually transmitted disease clinics in 3 Chinese cities-Guangzhou, Nanjing, and Tianjin-in 2012. Neisseria gonorrhoeae susceptibilities to penicillin and tetracycline were examined by detecting penicillinase-producing NG (PPNG) and high-level tetracycline-resistant NG, and NG susceptibilities to ciprofloxacin, spectinomycin, ceftriaxone, and cefixime were determined using an agar dilution method. Neisseria gonorrhoeae isolates were typed by multiple-locus variable number tandem repeat analysis. We conducted a χ analysis to compare clusters with Bonferroni correction and Kruskal-Wallis test. RESULTS: Neisseria gonorrhoeae isolates gathered from the 3 cities differed significantly in the prevalence of tetracycline-resistant NG (P < 0.001) and NG treated with ceftriaxone with a minimum inhibitory concentration of 0.125 mg/L or higher (P < 0.001). The analysis of the combination of the 7 variable number of tandem repeats loci for all of the 244 isolates yielded 110 multiple-locus variable number tandem repeat analysis types falling into 5 clusters. Cluster III was associated with PPNG, whereas cluster II was associated with non-PPNG (P < 0.05) and NG treated with ceftriaxone with a minimum inhibitory concentration of 0.125 mg/L or higher (P < 0.05). CONCLUSIONS: Antimicrobials that can be used with confidence to treat NG infection currently in China include ceftriaxone and spectinomycin, but not penicillin, tetracycline, ciprofloxacin, and cefixime. Moreover, some of the resulting clusters were associated with PPNG and NG with decreased ceftriaxone susceptibility.

Protective role and related mechanism of Gnaq in neural cells damaged by oxidative stress.

Gnaq is a member of G protein family and is rich in brain tissue. It has attracted the attention of many researchers in melanoma due to its high ratio of mutation. We have previously reported that the expression level of Gnaq in the mouse forebrain cortex was significantly decreased with age. Oxidative stress (OS) is the main cause leading to brain aging and related diseases. The roles and mechanisms of Gnaq in antioxidation in the brain have not been fully explored. In the present study, gene recombinant technique and lentivirus transfection technique were used to generate a Gnaq-overexpression cell model (Gnaq-SY5Y) coupled with H2O2 to build an OS model. The viability of cells, concentration of reactive oxygen species (ROS), apoptosis-related proteins (Bcl-2 and Bax), and signal pathways (NF-κB and Erk1/2) were compared between model cells and control cells. Results showed that the antioxidative ability of Gnaq-SY5Y cells was significantly improved. Concomitantly, the ROS level in Gnaq-SY5Y cells was significantly decreased whether the cells were subject to or not to H2O2 treatment. Anti-apoptotic protein Bcl-2 was up-regulated and apoptosis-promoting protein Bax was down-regulated in Gnaq-SY5Y cells after treatment with H2O2. NF-κB and phosphorylated Erk1/2 (p-Erk1/2) was significantly down-regulated in Gnaq-SY5Y cells. H2O2 treatment decreased Gnaq expression but increased NF-κB and p-Erk1/2 expressions in Gnaq-SY5Y cells. It is therefore concluded that Gnaq plays a pivotal role in antioxidation in neural cells. A possible mechanism for this would be that the overexpressed Gnaq inhibits the cellular damaging effect mediated by NF-κB and Erk1/2 signal pathways.

First nationwide study regarding ceftriaxone resistance and molecular epidemiology of Neisseria gonorrhoeae in China.

OBJECTIVES: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major public health concern worldwide. This is the first nationwide study, performed within the China Gonococcal Antimicrobial Susceptibility Programme (China-GASP), regarding AMR, including ceftriaxone genetic resistance determinants, and molecular epidemiology of gonococci in China. METHODS: Gonococcal isolates (n = 1257) from consecutive patients were collected at 11 sentinel sites distributed across China during 2012-13. Susceptibility to ceftriaxone, spectinomycin, ciprofloxacin and tetracycline was determined using the agar dilution method. Ceftriaxone resistance determinants penA and penB were examined using sequencing. N. gonorrhoeae multiantigen sequence typing (NG-MAST) was performed for molecular epidemiology. RESULTS: Among isolates, 0.2% were resistant to spectinomycin, 4.4% to ceftriaxone, 42.9% to tetracyclines (high-level resistance) and 99.8% to ciprofloxacin. Among 890 sequenced isolates, 16 (1.8%) possessed a penA mosaic allele; 4 of these isolates belonged to the MDR internationally spread NG-MAST genogroup G1407 (first description in China). Non-mosaic penA alleles with an A501T mutation and an A102D alteration in porB1b were statistically associated with decreased susceptibility/resistance to ceftriaxone. NG-MAST G10339, G1424 and G1053 were associated with decreased susceptibility/resistance to ceftriaxone. CONCLUSIONS: In China, ceftriaxone and spectinomycin can continue to be recommended for gonorrhoea treatment, with the possible exception of Hainan and Sichuan provinces where ceftriaxone resistance exceeded 5% and AMR surveillance needs to be strengthened. Molecular approaches including genotyping and AMR determinant analysis can be valuable to supplement and enhance conventional surveillance of gonococcal AMR in China.

Antimicrobial resistance, genetic resistance determinants for ceftriaxone and molecular epidemiology of Neisseria gonorrhoeae isolates in Nanjing, China.

OBJECTIVES: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major problem worldwide. This study investigated the AMR, genetic ceftriaxone resistance determinants and molecular epidemiology of N. gonorrhoeae in Nanjing, China. METHODS: N. gonorrhoeae isolates were collected in 2007 (n = 198) and 2012 (n = 80). The susceptibility to ceftriaxone, spectinomycin, ciprofloxacin and tetracycline was determined using an agar-dilution method. The ceftriaxone resistance determinants penA, mtrR and penB were examined using sequencing. N. gonorrhoeae multi-antigen sequence typing (NG-MAST) was performed for molecular epidemiology. RESULTS: All isolates were resistant to ciprofloxacin, 42.4% produced ß-lactamase and 34.9% showed high-level resistance to tetracycline (MIC ≥16 mg/L). In total, 5.4% of isolates were resistant to ceftriaxone; however, all of these isolates were obtained in 2007 and the susceptibility to ceftriaxone appeared to have increased. All isolates were susceptible to spectinomycin. No penA mosaic alleles were found. Non-mosaic penA alleles with A501T and G542S alterations, an H105Y alteration in mtrR and an A102D/N alteration in porB1b were statistically associated with decreased susceptibility or resistance to ceftriaxone. The most prevalent NG-MAST sequence types (STs) were ST568 (n = 13), ST270 (n = 9) and ST421 (n = 7). ST270 was the most common ST in isolates with decreased susceptibility or resistance to ceftriaxone. CONCLUSIONS: Ceftriaxone, ideally 500 mg and together with azithromycin (1-2 g), should be recommended for treatment of gonorrhoea in Nanjing, China. However, N. gonorrhoeae strains with resistance to ceftriaxone have been found in Nanjing. NG-MAST and ceftriaxone resistance determinant analysis can be valuable to supplement the antimicrobial resistance surveillance in China, which needs to be further strengthened.

Characterisation of blaTEM genes and types of ß-lactamase plasmids in Neisseria gonorrhoeae - the prevalent and conserved blaTEM-135 has not recently evolved and existed in the Toronto plasmid from the origin.

BACKGROUND: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major concern worldwide. It has been recently feared that the blaTEM-1 gene is, via blaTEM-135, evolving into an extended-spectrum ß-lactamase (ESBL), which could degrade all cephalosporins including ceftriaxone. The aims of the present study were to characterize the blaTEM genes, types of ß-lactamase plasmids, the degradation of ampicillin by TEM-135 compared to TEM-1, and to perform molecular epidemiological typing of ß-lactamase-producing N. gonorrhoeae strains internationally. METHODS: ß-lactamase producing N. gonorrhoeae isolates (n = 139) cultured from 2000 to 2011 in 15 countries were examined using antibiograms, blaTEM gene sequencing, ß-lactamase plasmid typing, and N. gonorrhoeae multiantigen sequence typing (NG-MAST). Furthermore, the blaTEM gene was sequenced in the first described Toronto plasmid (pJD7), one of the first Asian plasmids (pJD4) and African plasmids (pJD5) isolated in Canada. The degradation of ampicillin by TEM-135 compared to TEM-1 was examined using a MALDI-TOF MS hydrolysis assay. RESULTS: Six different blaTEM sequences were identified (among isolates with 125 different NG-MAST STs), i.e. blaTEM-1 (in 104 isolates), blaTEM-135 (in 30 isolates), and four novel blaTEM sequences (in 5 isolates). The blaTEM-1 allele was only found in the African and Asian plasmids, while all Rio/Toronto plasmids possessed the blaTEM-135 allele. Most interesting, the first described gonococcal Toronto plasmid (pJD7), identified in 1984, also possessed the highly conserved blaTEM-135 allele. The degradation of ampicillin by TEM-135 compared to TEM-1 was indistinguishable in the MALDI-TOF MS hydrolysis assay. CONCLUSIONS: blaTEM-135, encoding TEM-135, is predominantly and originally associated with the Rio/Toronto plasmid and prevalent among the ß-lactamase producing gonococcal strains circulating globally. blaTEM-135 does not appear, as previously hypothesized, to have recently evolved due to some evolutionary selective pressure, for example, by the extensive use of extended-spectrum cephalosporins worldwide. On the contrary, the present study shows that blaTEM-135 existed in the Toronto plasmid from its discovery and that blaTEM-135 is highly conserved (not further evolved in the past >30 years). Nevertheless, international studies for monitoring the presence of different blaTEM alleles, the possible evolution of the blaTEM-135 allele, and the types of ß-lactamase producing plasmids, remain imperative.