Household transmission of non-toxigenic diphtheria toxin gene-bearing Corynebacterium diphtheriae following a cluster of cutaneous cases in a specialist outpatient setting.

Introduction. Combination of PCR and Elek testing to identify toxigenic corynebacteria has revealed organisms described as non-toxigenic toxin-gene bearing (NTTB) Corynebacterium diphtheriae or C. ulcerans (i.e. PCR tox positive; Elek negative). These organisms carry part or all of tox, but are unable to express diphtheria toxin (DT) and present a challenge to clinical and public health case management.Gap analysis/Hypothesis. There are few data on the theoretical risk of NTTB reversion to toxigenicity. This unique cluster and subsequent epidemiologically linked isolates allowed the opportunity to determine any change in DT expression status.Aim. To characterize a cluster of infections due to NTTB in a skin clinic and subsequent cases in two household contacts.Methodology. Epidemiological and microbiological investigations were carried out according to existing national guidance at the time. Susceptibility testing used gradient strips. The tox operon analysis and multi-locus sequence typing (MLST) was derived from whole-genome sequencing. Alignment of the tox operon and phylogenetic analyses were performed using clustalW, mega, the public core-genome MLST (cgMLST) scheme and an in-house bioinformatic single nucleotide polymorphism (SNP) typing pipeline.Results. Isolates of NTTB C. diphtheriae were recovered from four cases (cases 1 to 4) with epidermolysis bullosa attending the clinic. Two further isolates were subsequently recovered from case 4, >18 months later, and from two household contacts (cases 5 and 6) after a further 18 months and 3.5 years, respectively. All eight strains were NTTB C. diphtheriae biovar mitis, belonged to the same sequence type (ST-336) with the same deletion in tox. Phylogenetic analysis showed relatively high diversity between the eight strains with 7-199 SNP and 3-109 cgMLST loci differences between them. The number of SNPs between the three isolates from case 4 and two household contacts (cases 5 and 6) was 44-70 with 28-38 cgMLST loci differences.Conclusions. We report a cluster of NTTB C. diphtheriae cases in a skin clinic and evidence of onward household transmission. We conclude the deletion in the tox was responsible for the non-expression of DT. There was no evidence of reversion to DT expression over the 6.5 year period studied. These data informed revision to guidance in the management of NTTB cases and their contacts in the UK.

Does electronic consent improve the logistics and uptake of HPV vaccination in adolescent girls? A mixed-methods theory informed evaluation of a pilot intervention.

OBJECTIVES: To evaluate the usability and acceptability of an electronic consent pilot intervention for school-based immunisations and assess its impact on consent form returns and human papilloma virus (HPV) vaccine uptake. DESIGN: Mixed-methods theory-informed study applying qualitative methods to examine the usability and acceptability of the intervention and quantitative methods to assess its impact. SETTING AND PARTICIPANTS: The intervention was piloted in 14 secondary schools in seven London boroughs in 2018. Intervention schools were matched with schools using paper consent based on the proportion of students with English as a second language and students receiving free school meals. Participants included nurses, data managers, school-link staff, parents and adolescents. INTERVENTIONS: An electronic consent portal where parents could record whether they agreed to or declined vaccination, and nurses could access data to help them manage the immunisation programme. PRIMARY AND SECONDARY OUTCOME MEASURES: Comparison of consent form return rates and HPV vaccine uptake between intervention and matched schools. RESULTS: HPV vaccination uptake did not differ between intervention and matched schools, but timely consent form return was significantly lower in intervention schools (73.3% vs 91.6%, p=0.008). The transition to using electronic consent was not straightforward, while schools and staff understood the potential benefits, they found it difficult to adapt to new ways of working which removed some level of control from schools. Reasons for lower consent form return in e-consent schools included difficulties encountered by some parents in accessing and using the intervention. Adolescents highlighted the potential for electronic consent to by-pass their information needs. CONCLUSIONS: The pilot intervention did not improve consent form return or vaccine uptake due to challenges encountered in transitioning to new working practice. New technologies require embedding before they become incorporated in everyday practice. A re-evaluation once stakeholders are accustomed with electronic consent may be required to understand its impact.

An unusual outbreak of norovirus associated with a Halloween-themed swimming pool party in England, 2016.

In October 2016, an outbreak of norovirus occurred among attendees of a Halloween-themed party at a public swimming pool in the south-east of England. Norovirus genogroup II was confirmed in 11 cases. In the retrospective cohort study of pool users, 68 individuals (37 female and 31 male), with a median age of 11 years (range: 0-50 years), met the case definition of developing diarrhoea or vomiting between 6 and 72 h after the pool visit. Multivariable analysis showed that increasing age was associated with a reduced risk of illness (odds ratio = 0.91; 95% confidence interval: 0.83-0.99). Pool behaviours (swallowing water) and the timing of visit (attending pool party after automatic dosing system was switched off) were independently associated with increased risk. Environmental investigations revealed that the automatic dosing system was switched off to reduce chlorine levels to an intended range of 0.5-1 parts per million to facilitate the use of a commercial red dye. There was a lack of compliance with the operator's own pool operating procedures, particularly on maintaining effective chlorine levels in pool water, recording of test results and recording of actions undertaken. This outbreak highlights the risks of lowering chlorine levels when using pool water colourants.