Investigating the cause of increased tetracycline-resistant Neisseria gonorrhoeae in England, 2016-20.

BACKGROUND: Antimicrobial resistance in Neisseria gonorrhoeae is a global public health concern. Tetracycline resistance (TetR) increased from 39.4% to 75.2% between 2016 and 2021 in N. gonorrhoeae isolates collected through national surveillance in England, despite the absence of use of tetracyclines for the treatment of gonorrhoea. OBJECTIVES: We investigated whether there was correlation between bacterial sexually transmitted infection (STI) tests performed and treatment with antimicrobials, with increased TetR in N. gonorrhoeae. METHODS: We examined correlations between bacterial STI tests, antimicrobial treatment and TetR in N. gonorrhoeae, using national surveillance data from three large sexual health services (SHS) in London during 2016-20. Doxycycline prescribing data and antibiograms of a non-STI pathogen from distinct patient groups (sexual health, obstetric and paediatric), at a large London hospital, were analysed to identify if doxycycline use in SHS was associated with resistance in a non-STI organism. RESULTS: A substantial increase in TetR was observed, particularly in isolates from gay, bisexual and other MSM (GBMSM). Strong positive correlations were observed exclusively in GBMSM between N. gonorrhoeae TetR and both bacterial STI tests (r = 0.97, P = 0.01) and antimicrobial treatment (r = 0.87, P = 0.05). Doxycycline prescribing increased dramatically during the study period in SHS. Prevalence of TetR in Staphylococcus aureus was higher in isolates sourced from SHS attendees than those from other settings. CONCLUSIONS: Frequent screening of GBMSM at higher risk of STIs, such as those on pre-exposure prophylaxis (PrEP) leading to/and increased use of doxycycline for the treatment of diagnosed infections, may account for the increase in TetR in N. gonorrhoeae.

Retrospective testing for mpox virus in routine STI screens from men who have sex with men in England, August-October 2022.

OBJECTIVES: A global outbreak of mpox (monkeypox) has been ongoing since 2022, with most cases in the UK detected in gay, bisexual and other men who have sex with men (GBMSM). Asymptomatic and pauci-symptomatic mpox infection has been reported outside of the UK. We aimed to investigate whether mpox could be detected in specimens from GBMSM in England who were attending sexual health services (SHSs) for asymptomatic sexually transmitted infection screening. METHODS: Anonymised, residual clinical specimens from GBMSM undertaking routine asymptomatic screening for gonorrhoea (Neisseria gonorrhoeae (NG)) and chlamydia (Chlamydia trachomatis (CT)) infection were tested for the presence of mpox virus. Specimens were collected between 1 August and 7 October 2022 from three SHSs in high-mpox incidence areas in England. Testing was performed using a dual-clade, mpox virus-specific real-time PCR. RESULTS: During the collection period, 2927 clinical specimens (951 pharyngeal swabs, 1022 urine specimens and 954 rectal swabs) were obtained from 1159 GBMSM. Mpox virus was detected in four specimens from two participants who attended the same SHS at different times (the first during the week 8-12 of August, the second during the week 19-23 of September). One participant was positive in the urine specimen only, while the other tested positive at all three sites. CONCLUSIONS: A very low prevalence (2 of 1159, 0.17%) of mpox infection was detected in GBMSM attending SHS in England for asymptomatic NG/CT screening, suggesting that undetected infection in this population was unlikely to be a main driver of transmission. Confirmed mpox cases in the UK declined from over 1100 per month in June and July to 764 cumulatively during the collection period. These data give reassurance that the observed reduction in cases during the collection period was not due to undetected infection or changes in presentation among SHS attendees. Currently, there is insufficient evidence to support routine testing of asymptomatic GBMSM for mpox infection in England.

An ENU-induced mutation in mouse glycyl-tRNA synthetase (GARS) causes peripheral sensory and motor phenotypes creating a model of Charcot-Marie-Tooth type 2D peripheral neuropathy.

Mutations in the enzyme glycyl-tRNA synthetase (GARS) cause motor and sensory axon loss in the peripheral nervous system in humans, described clinically as Charcot-Marie-Tooth type 2D or distal spinal muscular atrophy type V. Here, we characterise a new mouse mutant, Gars(C201R), with a point mutation that leads to a non-conservative substitution within GARS. Heterozygous mice with a C3H genetic background have loss of grip strength, decreased motor flexibility and disruption of fine motor control; this relatively mild phenotype is more severe on a C57BL/6 background. Homozygous mutants have a highly deleterious set of features, including movement difficulties and death before weaning. Heterozygous animals have a reduction in axon diameter in peripheral nerves, slowing of nerve conduction and an alteration in the recovery cycle of myelinated axons, as well as innervation defects. An assessment of GARS levels showed increased protein in 15-day-old mice compared with controls; however, this increase was not observed in 3-month-old animals, indicating that GARS function may be more crucial in younger animals. We found that enzyme activity was not reduced detectably in heterozygotes at any age, but was diminished greatly in homozygous mice compared with controls; thus, homozygous animals may suffer from a partial loss of function. The Gars(C201R) mutation described here is a contribution to our understanding of the mechanism by which mutations in tRNA synthetases, which are fundamentally important, ubiquitously expressed enzymes, cause axonopathy in specific sets of neurons.

The after-hours mutant reveals a role for Fbxl3 in determining mammalian circadian period.

By screening N-ethyl-N-nitrosourea-mutagenized animals for alterations in rhythms of wheel-running activity, we identified a mouse mutation, after hours (Afh). The mutation, a Cys(358)Ser substitution in Fbxl3, an F-box protein with leucine-rich repeats, results in long free-running rhythms of about 27 hours in homozygotes. Circadian transcriptional and translational oscillations are attenuated in Afh mice. The Afh allele significantly affected Per2 expression and delayed the rate of Cry protein degradation in Per2::Luciferase tissue slices. Our in vivo and in vitro studies reveal a central role for Fbxl3 in mammalian circadian timekeeping.