Neisseria gonorrheoae is the causative agent of gonorrhea, a sexually transmitted infection responsible for a major burden of disease with a high global prevalence. Protective immunity to infection is often not observed in humans, possible due to high variability of key antigens, induction of blocking antibodies, or a large number of infections being relatively superficial and not inducing a strong immune response. N. gonorrhoeae is a strictly human pathogen, however, studies using mouse models provide useful insights into the immune response to gonorrhea. In mice, N. gonorrhoea appears to avoid a protective Th1 response by inducing a less protective Th17 response. In mouse models, candidate vaccines which provoke a Th1 response can accelerate the clearance of gonococcus from the mouse female genital tract. Human studies indicate that natural infection often induces a limited immune response, with modest antibody responses, which may correlate with the clinical severity of gonococcal disease. Studies of cytokine responses to gonococcal infection in humans provide conflicting evidence as to whether infection induces an IL-17 response. However, there is evidence for limited induction of protective immunity from a study of female sex workers in Kenya. A controlled human infection model (CHIM) has been used to examine the immune response to gonococcal infection in male volunteers, but has not to date demonstrated protection against re-infection. Correlates of protection for gonorrhea are lacking, which has hampered the progress towards developing a successful vaccine. However, the finding that the Neisseria meningitidis serogroup B vaccines, elicit cross-protection against gonorrhea has invigorated the gonococcal vaccine field. More studies of infection in humans, either natural infection or CHIM studies, are needed to understand better gonococcal protective immunity.

The incidence of disseminated gonococcal infection (DGI) is rising in some parts of the world, but there is paucity of data on its true incidence from sub-Saharan Africa. DGI has varied manifestations in different population group. We report a case of a 30-year-old sexually active woman presenting with hemorrhagic symptoms 2 weeks after a surgery on account of diagnosis of uterine fibroid made at a peripheral hospital. A multidrug-resistant Neisseria gonorrhoeae was isolated from the wound on her surgical site and blood sample. She was managed with intravenous meropenem, pressure dressing, and blood products, with the patient making a full recovery after a week. This case is presented because it is a rare one. Moreover, there is the need to revive the awareness of clinicians on the existence of multidrug-resistant gonococcus in our environment. We herein report a case of DGI from Nigeria.

The lack of effective first-line antibiotic treatments against Neisseria gonorrhoeae, and the worldwide dissemination of resistant strains, are the main drivers of a worsening global health crisis. β-lactam antibiotics have been the backbone of therapeutic armamentarium against gonococci. However, we are lacking critical insights to design rationally optimized therapies. In the present work, we generated the first PBP-binding data set on 18 currently available and clinically relevant β-lactams and 4 β-lactamase inhibitors in two N. gonorrhoeae ATCC type collection strains, 19424 and 49226 (PBP2 type XXII and A39T change in mtrR). PBP binding (IC50) was determined via the Bocillin FL binding assay in isolated membrane preparations. Three clusters of differential PBP IC50s were identified and were mostly consistent across both strains, but with quantitative differences. Carbapenems were coselective for PBP2 and PBP3 (0.01 to 0.03 mg/L). Third- and fourth-generation cephalosporins cefixime, cefotaxime, ceftazidime, cefepime, and ceftriaxone showed the lowest IC50 values for PBP2 (0.01 mg/L), whereas cefoxitin, ceftaroline, and ceftolozane required higher concentrations (0.04 to >2 mg/L). Aztreonam was selective for PBP2 in both strains (0.03 to 0.07 mg/L); amdinocillin bound this PBP at higher concentrations (1.33 to 2.94 mg/L). Penicillins specifically targeted PBP2 in strain ATCC 19424 (0.02 to 0.19 mg/L) and showed limited inhibition in strain ATCC 49226 (0.01 to >2 mg/L). Preferential PBP2 binding was observed by β-lactam-based β-lactamase inhibitors sulbactam and tazobactam (1.07 to 6.02 mg/L); meanwhile, diazabicyclooctane inhibitors relebactam and avibactam were selective for PBP3 (1.27 to 5.40 mg/L). This data set will set the bar for future studies that will help the rational use and translational development of antibiotics against multidrug-resistant (MDR) N. gonorrhoeae. IMPORTANCE The manuscript represents the first N. gonorrhoeae PBP-binding data set for 22 chemically different drugs in two type strains with different genetic background. We have identified three clusters of drugs according to their PBP binding IC50s and highlighted the binding differences across the two strains studied. With the currently available genomic information and the PBP-binding data, we have been able to correlate the target attainment differences and the mutations that affect the drug uptake with the MIC changes. The results of the current work will allow us to develop molecular tools of great practical use for the study and the design of new rationally designed therapies capable of combating the growing MDR gonococci threat.

Due to the increased resistance to all available antibiotics and the lack of vaccines, Neisseria gonorrhoeae (the gonococcus) poses an urgent threat. Although the mechanisms of virulence and antibiotic resistance have been largely investigated in this bacterium, very few studies have addressed the stringent response (SR) that in pathogenic bacteria controls the expression of genes involved in host-pathogen interaction and tolerance and persistence toward antibiotics. In this study, the results of the transcriptome analysis of a clinical isolate of N. gonorrhoeae, after induction of the SR by serine hydroxamate, provided us with an accurate list of genes that are transcriptionally modulated during the SR. The list includes genes associated with metabolism, cellular machine functions, host-pathogen interaction, genome plasticity, and antibiotic tolerance and persistence. Moreover, we found that the artificial induction of the SR in N. gonorrhoeae by serine hydroxamate is prevented by thiostrepton, a thiopeptide antibiotic that is known to interact with ribosomal protein L11, thereby inhibiting functions of EF-Tu and EF-G, and binding of pppGpp synthase I (RelA) to ribosome upon entry of uncharged tRNA. We found that N. gonorrhoeae is highly sensitive to thiostrepton under in vitro conditions, and that thiostrepton, in contrast to other antibiotics, does not induce tolerance or persistence. Finally, we observed that thiostrepton attenuated the expression of key genes involved in the host-pathogen interaction. These properties make thiostrepton a good drug candidate for dampening bacterial virulence and preventing antibiotic tolerance and persistence. The ongoing challenge is to increase the bioavailability of thiostrepton through the use of chemistry and nanotechnology.

OBJECTIVE: Extra-genital manifestations of gonococcal infection are rare (0.5-3%). Among them, gonococcal arthritis (GA) is the most frequent, accounting for 30-90% of disseminated infections. Our study aimed to describe all hospital cases of GA in Reunion Island, a French overseas territory.
METHODS: We conducted a retrospective, multicentric, observational study of all cases of certain, probable or possible GA from 2008 to 2020.
RESULTS: We identified 58 cases of GA, mostly certain cases (n = 48). Sex ratio was balanced, but men were older than women (51 vs 27 years, p < 0.001). A total of 41% had travelled abroad during the previous 3 months, mostly in Madagascar or South-East Asia. The most frequently infected joint was the knee, followed by ankle, wrist and fingers or carpal joints. Only 16% of cases had genital symptoms, but 50% had another extra-genital manifestation, mainly skin lesions (40%). Positivity rate of joint puncture was 91%, with a purulent liquid. Only 58% had a positive culture, and 33% had only a positive PCR. There was no 3GC-resistant strain. In comparison with gonococcal infection without arthritis, patients were older and had fewer genital but more extra-genital symptoms. On discharge 60% had persistent articular symptoms. GA represented 18% of all hospitalised septic arthritis cases with microbial identification in 2019.
CONCLUSIONS: GA is rare but it is important to make an early diagnosis and treat promptly, as joint destruction may be important, leading to persistent symptoms after discharge. PCR use in joint puncture is useful in cases with negative culture.

OBJECTIVE: Gonococcal infections with a higher bacterial load may pose a higher risk of transmission. We assessed the association between gonococcal bacterial load and coinfection with Mycoplasma genitalium.
METHODS: From September 2015 until May 2018, 200 men and transgender women who have sex with men participated in an HIV pre-exposure prophylaxis (PrEP) demonstration trial in Antwerp, Belgium. They underwent 3-monthly 3-site (anus, urine, and pharynx) molecular testing for N. gonorrhoeae and C. trachomatis and M. genitalium, irrespective of symptoms. Gonococcal bacterial load was determined on remnant DNA extracts using an in-house quantitative PCR. Results were expressed as log10 transformed copies/mL and analyzed with a linear regression model.
RESULTS: Gonococcal bacterial load could be determined for 82 (80.4%) of 102 anal, 17 (73.9%) of 23 urine, and 64 (90.1%) of 71 pharyngeal samples. M. genitalium was detected in five of these anal, two urine, and two pharyngeal samples and C. trachomatis was detected in 16 anal, one urine, and two pharyngeal samples. Gonococcal bacterial load was significantly higher in the presence of M. genitalium (difference 0.92 log copies/mL, 95% CI 0.16-1.67).
CONCLUSIONS: Gonococcal bacterial load was higher with M. genitalium coinfection. M. genitalium may thus be a cofactor in gonococcal transmission.

We report a case of infectious endocarditis due to Neisseria gonorrhoeae in a 38-year-old male patient with no cardiovascular risk factors or past medical history who presented with prolonged febrile illness, asthenia and weight loss. The blood cultures were positive for gonococcus. He received antibiotic treatment with ceftriaxone for 29 days. The patient developed severe aortic regurgitation and underwent surgical aortic valve replacement with a bileaflet mechanical prosthesis, with favorable outcome.
Se presenta un caso de endocarditis infecciosa por Neisseria gonorrhoeae, en un paciente masculino de 38 años, sin factores de riesgo cardiovascular ni otros antecedentes previos. La sospecha diagnóstica comienza por síndrome febril prolongado, astenia y pérdida de peso, confirmada con rescate de gonococo en los hemocultivos. Cumplió tratamiento antibiótico con ceftriaxona por 29 días. Evoluciona con insuficiencia aórtica grave por lo cual se realiza cirugía de reemplazo valvular por prótesis mecánica bidisco exitosa, con una evolución favorable.

BACKGROUND: Despite decades of research efforts, development of a gonorrhea vaccine has remained elusive. Epidemiological studies suggest that detoxified outer membrane vesicle (dOMV) vaccines from Neisseria meningitidis (Nm) may protect against infection with Neisseria gonorrhoeae (Ng). We recently reported that Nm dOMVs lacking the major outer membrane proteins (OMPs) PorA, PorB, and RmpM induced greater antibody cross-reactivity against heterologous Nm strains than wild-type (WT) dOMVs and may represent an improved vaccine against gonorrhea.
METHODS: We prepared dOMV vaccines from meningococcal strains that were sufficient or deleted for PorA, PorB, and RmpM. Vaccines were tested in a murine genital tract infection model and antisera were used to identify vaccine targets.
RESULTS: Immunization with Nm dOMVs significantly and reproducibly enhanced gonococcal clearance for mice immunized with OMP-deficient dOMVs; significant clearance for WT dOMV-immunized mice was observed in one of two experiments. Clearance was associated with serum and vaginal anti-Nm dOMV IgG antibodies that cross-reacted with Ng. Serum IgG was used to identify putative Ng vaccine targets, including PilQ, MtrE, NlpD, and GuaB.
CONCLUSIONS: Meningococcal dOMVs elicited a protective effect against experimental gonococcal infection. Recognition and identification of Ng vaccine targets by Nm dOMV-induced antibodies supports the development of a cross-protective Neisseria vaccine.

Gonorrhoea, caused by Neisseria gonorrhoeae, is a major global public health concern. Homoserine dehydrogenase (HSD), a key enzyme in the aspartate pathway, is a promising metabolic target against pathogenic infections. In this study, a monofunctional HSD from N. gonorrhoeae (NgHSD) was overexpressed in Escherichia coli and purified to >95% homogeneity for biochemical characterization. Unlike the classic dimeric structure, the purified recombinant NgHSD exists as a tetramer in solution. We determined the enzymatic activity of recombinant NgHSD for l-homoserine oxidation, which revealed that this enzyme was NAD+ dependent, with an approximate 479-fold (kcat/Km) preference for NAD+ over NADP+, and that optimal activity for l-homoserine oxidation occurred at pH 10.5 and 40 °C. At 800 mM, neither NaCl nor KCl increased the activity of NgHSD, in contrast to the behavior of several reported NAD+-independent homologs. Moreover, threonine did not markedly inhibit the oxidation activity of NgHSD. To gain insight into the cofactor specificity, site-directed mutagenesis was used to alter coenzyme specificity. The double mutant L45R/S46R, showing the highest affinity for NADP+, caused a shift in coenzyme preference from NAD+ to NADP+ by a factor of ~974, with a catalytic efficiency comparable with naturally occurring NAD+-independent homologs. Collectively, our results should allow the exploration of drugs targeting NgHSD to treat gonococcal infections and contribute to the prediction of the coenzyme specificity of novel HSDs.

Multidrug-resistant bacteria are among the most important current threats to public health. Typically, they are associated with nosocomial infections. However, some have become prevalent causes of community-acquired infections, such as Neisseria gonorrhoeae, Shigella, Salmonella, and Streptococcus pneumoniae. The community spread of multidrug-resistant bacteria is also a crucial development. An important global threat on the horizon is represented by production of carbapenemases by community-acquired hypervirulent Klebsiella pneumoniae. Such strains have already been found in Asia, Europe, and North America. Prevention of further community spread of multidrug-resistant bacteria is of the utmost importance, and will require a multidisciplinary approach involving all stakeholders.