Evaluating the dynamics of hospital COVID-19 contacts and subsequent conversion to SARS-CoV-2 infection: a multi-centre retrospective cohort study.

We investigated the dynamics of COVID-19 contacts subsequent conversion to SARS-CoV-2 infection in an inpatient setting across three National Health Service (NHS) Trusts. 9.2% (476/5,156) COVID-19 contacts met inclusion criteria, were typable and tested positive for COVID-19. There was no significant difference between Omicron and non-Omicron contacts overall conversion proportions. Omicron contacts converted faster than non-Omicron contacts (median 3 days vs 4 days, P=0.03), and had significantly greater proportions of early conversions at day 3, 5, and 7 timepoints.

Routine Metagenomics Service for ICU Patients with Respiratory Infection.

Rationale: Respiratory metagenomics (RMg) needs evaluation in a pilot service setting to determine utility and inform implementation into routine clinical practice. Objectives: Feasibility, performance, and clinical impacts on antimicrobial prescribing and infection control were recorded during a pilot RMg service. Methods: RMg was performed on 128 samples from 87 patients with suspected lower respiratory tract infection (LRTI) on two general and one specialist respiratory ICUs at Guy's and St Thomas' NHS Foundation Trust, London. Measurements and Main Results: During the first 15 weeks, RMg provided same-day results for 110 samples (86%), with a median turnaround time of 6.7 hours (interquartile range = 6.1-7.5 h). RMg was 93% sensitive and 81% specific for clinically relevant pathogens compared with routine testing. Forty-eight percent of RMg results informed antimicrobial prescribing changes (22% escalation; 26% deescalation) with escalation based on speciation in 20 out of 24 cases and detection of acquired-resistance genes in 4 out of 24 cases. Fastidious or unexpected organisms were reported in 21 samples, including anaerobes (n = 12), Mycobacterium tuberculosis, Tropheryma whipplei, cytomegalovirus, and Legionella pneumophila ST1326, which was subsequently isolated from the bedside water outlet. Application to consecutive severe community-acquired LRTI cases identified Staphylococcus aureus (two with SCCmec and three with luk F/S virulence determinants), Streptococcus pyogenes (emm1-M1uk clone), S. dysgalactiae subspecies equisimilis (STG62647A), and Aspergillus fumigatus with multiple treatments and public health impacts. Conclusions: This pilot study illustrates the potential of RMg testing to provide benefits for antimicrobial treatment, infection control, and public health when provided in a real-world critical care setting. Multicenter studies are now required to inform future translation into routine service.

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.

The ongoing Streptococcus pyogenes (Group A Streptococcus) outbreak in London, United Kingdom, in December 2022: a molecular epidemiology study.

OBJECTIVES: Epidemiological and whole-genome sequencing analysis of an ongoing outbreak of Streptococcus pyogenes (Group A Streptococcus) in London (United Kingdom). METHODS: Prospective identification of Group A Streptococcus cases from a diagnostic laboratory serving central and south London between 27 November and 10 December 2022. Case notes were reviewed and isolates were retrieved. Case numbers were compared with the previous 5 years. Whole-genome sequencing was performed with long-read, nanopore technology for emm typing and identification of superantigen genes. Associations of pathogen-related factors with an invasive disease were assessed by single-variable and multi-variable logistic regression. RESULTS: Case numbers began increasing in October 2022 from a baseline of 2.0 cases per day, and in December 2022, the average daily case numbers reached 10.8 cases per day, four-fold the number usually seen in winter. A total of 113 cases were identified during the prospective study period. Three quarters (86/113, 76%) were paediatric cases, including 2 deaths. Of 113 cases, 11 (10%) were invasive. In total, 56 isolates were successfully sequenced, including 10 of 11 (91%) invasive isolates. The emm12 (33/56, 59%) and emm1 (9/56, 16%) types were predominant, with 7 of 9 (78%) emm1 isolates being from the M1uk clone. The majority of invasive isolates had superantigen genes spea (7/10, 70%) and spej (8/10, 80%), whereas, in non-invasive isolates, these superantigen genes were found less frequently (spea: 5/46, 11% and spej: 7/46, 15%). By multivariable analysis of pathogen-related factors, spea (OR 8.9, CI 1.4-57, p 0.020) and spej (OR 12, CI 1.8-78, p 0.011) were associated with invasive disease. CONCLUSIONS: emm12 and emm1 types predominate in the ongoing outbreak, which mainly affects children. In this outbreak, the spea and spej superantigen genes are associated with the severity of presentation.

Clinical features and management of human monkeypox: a retrospective observational study in the UK.

BACKGROUND: Cases of human monkeypox are rarely seen outside of west and central Africa. There are few data regarding viral kinetics or the duration of viral shedding and no licensed treatments. Two oral drugs, brincidofovir and tecovirimat, have been approved for treatment of smallpox and have demonstrated efficacy against monkeypox in animals. Our aim was to describe the longitudinal clinical course of monkeypox in a high-income setting, coupled with viral dynamics, and any adverse events related to novel antiviral therapies. METHODS: In this retrospective observational study, we report the clinical features, longitudinal virological findings, and response to off-label antivirals in seven patients with monkeypox who were diagnosed in the UK between 2018 and 2021, identified through retrospective case-note review. This study included all patients who were managed in dedicated high consequence infectious diseases (HCID) centres in Liverpool, London, and Newcastle, coordinated via a national HCID network. FINDINGS: We reviewed all cases since the inception of the HCID (airborne) network between Aug 15, 2018, and Sept 10, 2021, identifying seven patients. Of the seven patients, four were men and three were women. Three acquired monkeypox in the UK: one patient was a health-care worker who acquired the virus nosocomially, and one patient who acquired the virus abroad transmitted it to an adult and child within their household cluster. Notable disease features included viraemia, prolonged monkeypox virus DNA detection in upper respiratory tract swabs, reactive low mood, and one patient had a monkeypox virus PCR-positive deep tissue abscess. Five patients spent more than 3 weeks (range 22-39 days) in isolation due to prolonged PCR positivity. Three patients were treated with brincidofovir (200 mg once a week orally), all of whom developed elevated liver enzymes resulting in cessation of therapy. One patient was treated with tecovirimat (600 mg twice daily for 2 weeks orally), experienced no adverse effects, and had a shorter duration of viral shedding and illness (10 days hospitalisation) compared with the other six patients. One patient experienced a mild relapse 6 weeks after hospital discharge. INTERPRETATION: Human monkeypox poses unique challenges, even to well resourced health-care systems with HCID networks. Prolonged upper respiratory tract viral DNA shedding after skin lesion resolution challenged current infection prevention and control guidance. There is an urgent need for prospective studies of antivirals for this disease. FUNDING: None.

Evaluating the potential for respiratory metagenomics to improve treatment of secondary infection and detection of nosocomial transmission on expanded COVID-19 intensive care units.

BACKGROUND: Clinical metagenomics (CMg) has the potential to be translated from a research tool into routine service to improve antimicrobial treatment and infection control decisions. The SARS-CoV-2 pandemic provides added impetus to realise these benefits, given the increased risk of secondary infection and nosocomial transmission of multi-drug-resistant (MDR) pathogens linked with the expansion of critical care capacity. METHODS: CMg using nanopore sequencing was evaluated in a proof-of-concept study on 43 respiratory samples from 34 intubated patients across seven intensive care units (ICUs) over a 9-week period during the first COVID-19 pandemic wave. RESULTS: An 8-h CMg workflow was 92% sensitive (95% CI, 75-99%) and 82% specific (95% CI, 57-96%) for bacterial identification based on culture-positive and culture-negative samples, respectively. CMg sequencing reported the presence or absence of ß-lactam-resistant genes carried by Enterobacterales that would modify the initial guideline-recommended antibiotics in every case. CMg was also 100% concordant with quantitative PCR for detecting Aspergillus fumigatus from 4 positive and 39 negative samples. Molecular typing using 24-h sequencing data identified an MDR-K. pneumoniae ST307 outbreak involving 4 patients and an MDR-C. striatum outbreak involving 14 patients across three ICUs. CONCLUSION: CMg testing provides accurate pathogen detection and antibiotic resistance prediction in a same-day laboratory workflow, with assembled genomes available the next day for genomic surveillance. The provision of this technology in a service setting could fundamentally change the multi-disciplinary team approach to managing ICU infections. The potential to improve the initial targeted treatment and rapidly detect unsuspected outbreaks of MDR-pathogens justifies further expedited clinical assessment of CMg.

Cloth Lanyards as a Source of Intermittent Transmission of Candida auris on an ICU.

OBJECTIVES: Candida auris has been implicated in ICU outbreaks worldwide and is notable for being difficult to identify and treat, its resilience in the environment, and significant patient mortality associated with invasive disease. Here, we describe a small C. auris outbreak and how it was terminated. DESIGN: Single-center, observational. SETTING: Two general adult ICUs at an urban U.K. teaching hospital. PATIENTS: All patients positive for C. auris during the 5-month outbreak were included (n = 7). INTERVENTIONS: Stepwise implementation of enhanced infection prevention and control precautions was introduced including twice-weekly screening, contact tracing, isolation precautions, and environmental decontamination. A detailed environmental screen was performed to identify potential reservoirs. This included the patient bed space and clinical equipment and a frequently handled cloth lanyard attached to a key used to access controlled drugs. Personal possessions such as mobile phones, lanyards, and identification badges were also screened. MEASUREMENTS AND MAIN RESULTS: The index case and six linked acquisitions were identified. Four of six (67%) patients were identified after discharge of all known previous C. auris cases from ICU, highlighting potential for an environmental reservoir. Environmental screening identified C. auris from a patient bed space following deep cleaning, prompting review and enhancement of cleaning procedures. The controlled drug cloth lanyard was positive for C. auris, which prompted removal and culture of all staff lanyards. C. auris was identified on 1/100 staff lanyards (1%). No mobile phones or identification badges were positive for C. auris. The outbreak terminated following withdrawal of lanyards from ICU. CONCLUSIONS: This outbreak further implicates environmental reservoirs as sustaining C. auris ICU outbreaks. Identification of C. auris on cloth lanyards highlights the need to identify commonly handled moveable objects during an outbreak. We suggest that ICUs with a C. auris outbreak should investigate similar infrequently cleaned items as potential reservoirs and review their policies on lanyard use.

Retrospective analysis of diabetic foot osteomyelitis management and outcome at a tertiary care hospital in the UK.

OBJECTIVES: This study aimed to analyse retrospectively management and outcomes of the diabetic foot osteomyelitis (DFOM) multi-disciplinary team at St Thomas' Hospital, London. METHODS: Patients admitted during 2015 with diagnosis of DFOM were included. Data were obtained from medical and microbiology records. RESULTS: 275 patients were admitted for DF infection in 2015: 45.1% had OM (75% males). 40% were newly diagnosed with DF ulcer (DFU). 81% patients had X-ray and 28% had MRI. Bone infection was confirmed by MC&S in 53% cases. 930 microbiological isolates were obtained: 63% were Gram-positive microorganisms [S.aureus and MRSA (~40%), CoNS (20%), and E.faecalis (8%)]. All MRSA were vancomycin and linezolid sensitive. 23.2% isolates were vancomycin-resistant enterococci. 24% isolates were Gram-negative organisms: P.aeruginosa (42%), E.coli (13%), and E.cloacae (12%). Meropenem resistance was low; 5.4% P.aeruginosa, 87.5% A.baumanii. 76% patients received co-amoxiclav; 41% received ≥3 antibiotics; 17% received >3 months antibiotics. Hospital mean-length of stay was 26.1 days. Ulcer time-to-heal was >6 months in 25% patients. 22% ulcers healed without surgery, 60% healed after minor amputation, 12% patients had major amputation. CONCLUSION: Despite current MDT approach, many patients progress to amputation. DF-OM still represents a challenging clinical condition, requiring further study to develop better management guidelines.

Insidious Risk of Severe Mycobacterium chimaera Infection in Cardiac Surgery Patients.

BACKGROUND: An urgent UK investigation was launched to assess risk of invasive Mycobacterium chimaera infection in cardiothoracic surgery and a possible association with cardiopulmonary bypass heater-cooler units following alerts in Switzerland and The Netherlands. METHODS: Parallel investigations were pursued: (1) identification of cardiopulmonary bypass-associated M. chimaera infection through national laboratory and hospital admissions data linkage; (2) cohort study to assess patient risk; (3) microbiological and aerobiological investigations of heater-coolers in situ and under controlled laboratory conditions; and (4) whole-genome sequencing of clinical and environmental isolates. RESULTS: Eighteen probable cases of cardiopulmonary bypass-associated M. chimaera infection were identified; all except one occurred in adults. Patients had undergone valve replacement in 11 hospitals between 2007 and 2015, a median of 19 months prior to onset (range, 3 months to 5 years). Risk to patients increased after 2010 from <0.2 to 1.65 per 10000 person-years in 2013, a 9-fold rise for infections within 2 years of surgery (rate ratio, 9.08 [95% CI, 1.81-87.76]). Endocarditis was the most common presentation (n = 11). To date, 9 patients have died. Investigations identified aerosol release through breaches in heater-cooler tanks. Mycobacterium chimaera and other pathogens were recovered from water and air samples. Phylogenetic analysis found close clustering of strains from probable cases. CONCLUSIONS: We identified low but escalating risk of severe M. chimaera infection associated with heater-coolers with cases in a quarter of cardiothoracic centers. Our investigations strengthen etiological evidence for the role of heater-coolers in transmission and raise the possibility of an ongoing, international point-source outbreak. Active management of heater-coolers and heightened clinical awareness are imperative given the consequences of infection.

Immune Complex Mediated Glomerulonephritis with Acute Thrombotic Microangiopathy following Newly Detected Hepatitis B Virus Infection in a Kidney Transplant Recipient.

Hepatitis B virus (HBV) presents a risk to patients and staff in renal units. To minimise viral transmission, there are international and UK guidelines recommending HBV immunisation for patients commencing renal replacement therapy (RRT) and HBV surveillance in kidney transplant recipients. We report the case of a 56-year-old male who was immunised against HBV before starting haemodialysis. He received a deceased donor kidney transplant three years later, at which time there was no evidence of HBV infection. After a further six years he developed an acute kidney injury; allograft biopsy revealed an acute thrombotic microangiopathy (TMA) with glomerulitis, peritubular capillaritis, and C4d staining. Due to a "full house" immunoprofile, tests including virological screening were undertaken, which revealed acute HBV infection. Entecavir treatment resulted in an improvement in viral load and kidney function. HBV genotyping demonstrated a vaccine escape mutant, suggesting "past resolved" infection that reactivated with immunosuppression, though posttransplant acquisition cannot be excluded. This is the first reported case of acute HBV infection associated with immune complex mediated glomerulonephritis and TMA. Furthermore, it highlights the importance of HBV surveillance in kidney transplant recipients, which although addressed by UK guidelines is not currently practiced in all UK units.

Subcutaneous ivermectin use in the treatment of severe Strongyloides stercoralis infection: two case reports and a discussion of the literature.

BACKGROUND: Strongyloides stercoralis infection presents with varying degrees of severity, but it often primarily involves the small bowel. In severe infection and cases of hyperinfection, ileus and small-bowel obstruction may prevent enteral absorption of anthelminthics such as ivermectin. At present there are no parenteral anthelminthics licensed for use in humans. METHODS: Here, we describe two cases of severe S. stercoralis infection treated with an unlicensed veterinary preparation of subcutaneous ivermectin, and we discuss the published reports of the use of this treatment elsewhere. RESULTS: Both patients were successfully treated with subcutaneous ivermectin, and both recovered completely. CONCLUSIONS: Despite the limited published experience of parenteral ivermectin use, there is evidence that it may be a safe and effective treatment for severe strongyloidiasis. However, more data are needed to guide dosing schedules and monitoring for toxicity.

Hyperreactive Malarial Splenomegaly Syndrome--Can the Diagnostic Criteria Be Improved?

Hyperreactive Malarial Splenomegaly Syndrome (HMSS) was described and defined before sensitive tests for malaria were available. We present a series of seven individuals who were referred to our clinics with possible HMSS. Chronic malaria was demonstrated in those successfully treated but not in those who failed to respond to therapy. This observation suggests that the newer molecular malaria assays have a role to play in the identification of individuals who are likely to respond to treatment for HMSS in non-endemic regions.

Bacteroides-associated pylephlebitis in a patient with strongyloidiasis.

Strongyloidiasis is associated with Gram-negative bacteremia. Septic portal vein thrombosis or pylephlebitis is a rare but serious complication of intra-abdominal infection, and it is often associated with Bacteroides bacteremia. We present the first report of pylephlebitis with Bacteroides bacteremia associated with underlying Strongyloides stercoralis infection and briefly review the management of septic portal vein thrombosis.