Multi-modality detection of SARS-CoV-2 in faecal donor samples for transplantation and in asymptomatic emergency surgical admissions.

Background: Faecal transplantation is an evidence-based treatment for Clostridioides difficile. Patients infected with SARS-CoV-2 have been shown to shed the virus in stool for up to 33 days, well beyond the average clearance time for upper respiratory tract shedding. We carried out an analytical and clinical validation of reverse-transcriptase quantitative (RT-qPCR) as well as LAMP, LamPORE and droplet digital PCR in the detection of SARS-CoV-2 RNA in stool from donated samples for faecal microbiota transplantation (FMT), spiked samples and asymptomatic inpatients in an acute surgical unit.  Methods: Killed SARS-CoV-2 viral lysate and extracted RNA was spiked into donor stool & FMT and a linear dilution series from 10 -1 to 10 -5 and tested via RT-qPCR, LAMP, LamPORE and ddPCR against SARS-CoV-2. Patients admitted to the critical care unit with symptomatic SARS-CoV-2 and sequential asymptomatic patients from acute presentation to an acute surgical unit were also tested. Results: In a linear dilution series, detection of the lowest dilution series was found to be 8 copies per microlitre of sample. Spiked lysate samples down to 10 -2 dilution were detected in FMT samples using RTQPCR, LamPORE and ddPCR and down to 10 -1 with LAMP. In symptomatic patients 5/12 had detectable SARS-CoV-2 in stool via RT-qPCR and 6/12 via LamPORE, and in 1/97 asymptomatic patients via RT-qPCR. Conclusion: RT-qPCR can be detected in FMT donor samples using RT-qPCR, LamPORE and ddPCR to low levels using validated pathways. As previously demonstrated, nearly half of symptomatic and less than one percent of asymptomatic patients had detectable SARS-CoV-2 in stool.

Increased Usage of Antiseptics Is Associated with Reduced Susceptibility in Clinical Isolates of Staphylococcus aureus.

Hospital-acquired infection is a major cause of morbidity and mortality, and regimes to prevent infection are crucial in infection control. These include the decolonization of vulnerable patients with methicillin-resistant Staphylococcus aureus (MRSA) carriage using antiseptics, including chlorhexidine and octenidine. Concern has been raised, however, regarding the possible development of biocide resistance. In this study, we assembled a panel of S. aureus isolates, including isolates collected before the development of chlorhexidine and octenidine and isolates, from a major hospital trust in the United Kingdom during a period when the decolonization regimes were altered. We observed significant increases in the MIC and minimum bactericidal concentration (MBC) of chlorhexidine in isolates from periods of high usage of chlorhexidine. Isolates with increased MICs and MBCs of octenidine rapidly emerged after octenidine was introduced in the trust. There was no apparent cross-resistance between the two biocidal agents. A combination of variable-number tandem repeat (VNTR) analysis, PCR for qac genes, and whole-genome sequencing was used to type isolates and examine possible mechanisms of resistance. There was no expansion of a single strain associated with decreased biocide tolerance, and biocide susceptibility did not correlate with carriage of qac efflux pump genes. Mutations within the NorA or NorB efflux pumps, previously associated with chlorhexidine export, were identified, however, suggesting that this may be an important mechanism of biocide tolerance. We present evidence that isolates are evolving in the face of biocide challenge in patients and that changes in decolonization regimes are reflected in changes in susceptibility of isolates.IMPORTANCE Infection in hospitals remains a major cause of death and disease. One way in which we combat this is by decolonizing at-risk patients from carriage of bacteria which can cause disease such as MRSA. This is done with antiseptics, including chlorhexidine and octenidine. There is concern, however, that bacteria may be able to become resistant to these antiseptics. In this study, we looked at isolates of MRSA and found that there was a correlation between the use of antiseptics and increased resistance in the isolates. We also suggest that the mechanism by which these more tolerant isolates may become resistant to antiseptics is that of changing a transport pump that exports these agents. This information suggests that we need to study the impact of antiseptics on clinically important bacteria more closely.

CTX-M ESBL-producing Enterobacteriaceae: estimated prevalence in adults in England in 2014.

Background: ESBL-producing Enterobacteriaceae (ESBLPE) are increasing in prevalence worldwide and are more difficult to treat than non-ESBLPE. Their prevalence in the UK general population is unknown, as the only previous UK ESBLPE faecal colonization study involved patients with diarrhoea. Objectives: To estimate the prevalence of CTX-M ESBLPE faecal colonization in the general adult population of England in 2014, and investigate risk factors. Methods: A stratified random sample of 58 337 registered patients from 16 general practices within four areas of England were invited to participate by returning faeces specimens and self-completed questionnaires. Specimens were tested for ESBLPE and carbapenemase-producing Enterobacteriaceae (CPE). Results: 2430 individuals participated (4% of those invited). The estimated prevalence of colonization with CTX-M ESBLPE in England was 7.3% (95% CI 5.6%-9.4%) (Shropshire 774 participants, 4.9% colonization; Southampton City 740 participants, 9.2%; Newham 612 participants, 12.7%; Heart of Birmingham 234 individuals, 16.0%) and was particularly high in: those born in Afghanistan (10 participants, 60.0% colonization, 95% CI 29.7%-84.2%); those born on the Indian subcontinent (India, Pakistan, Bangladesh or Sri Lanka) (259 participants, 25.0% colonization, 95% CI 18.5%-32.9%); travellers to South Asia (India, Pakistan, Bangladesh, Sri Lanka or Nepal) in the last year (140 participants, 38.5% colonization, 95% CI 27.8%-50.5%); and healthcare domestics (8 participants, unweighted 37.5% colonization, 95% CI 8.5%-75.5%). Risk factors identified included: being born in the Indian subcontinent (aOR 5.4, 95% CI 3.0-9.7); travel to South Asia (aOR 2.9, 95% CI 1.8-4.8) or to Africa, China, South or Central America, South East or Pacific Asia or Afghanistan (aOR 2.6, 95% CI 1.7-4.1) in the last year; and working as a healthcare domestic (aOR 6.2, 95% CI 1.3-31). None of the 48 participants who took co-amoxiclav in the last year was colonized with CTX-M ESBLPE. blaCTX-M-15 accounted for 66% of CTX-M ESBLPE positives. 0.1% (two participants) were colonized with CPE. Conclusions: CTX-M ESBLPE are established in the general population in England and prevalence is particularly high in people from certain countries of birth or with recent travel. We recommend that these findings be taken into account in guidance on the empirical management of patients presenting with a likely Enterobacteriaceae infection.

Informing future research for carriage of multiresistant Gram-negative bacteria: problems with recruiting to an English stool sample community prevalence study.

OBJECTIVES: This study aims to highlight problems with recruiting to an English stool sample community prevalence study. It was part of a larger cross-sectional research to determine the risk factors for the presence of extended-spectrum beta-lactamase and carbapenemase-producing coliforms in stool samples of the asymptomatic general English population. SETTING: Four National Health Service primary care trusts (PCTs) of England representing a different section of the population of England: Newham PCT; Heart of Birmingham Teaching PCT; Shropshire County PCT; and Southampton City PCT. PARTICIPANTS: Sixteen general practices across the four PCTs were purposefully selected. After stratification of GP lists by age, ethnicity and antibiotic use, 58 337 randomly selected patients were sent a postal invitation.Patients who had died, moved to a different surgery, were deemed too ill by their General Practitioner or hospitalised at the time of mailing were excluded. RESULTS: Stool and questionnaire returns varied by area, age, gender and ethnicity; the highest return rate of 27.3% was in Shropshire in the age group of over 60 years; the lowest, 0.6%, was in Birmingham in the age group of 18-39 years. Whereas only 3.9%(2296) returned a completed questionnaire and stool sample, 94.9% of participants gave permission for their sample and data to be used in future research. CONCLUSION: Researchers should consider the low stool specimen return rate and wide variation by ethnicity and age when planning future studies involving stool specimen collection. This is particularly pertinent if the study has no health benefit to participants. Further research is needed to explore how to improve recruitment in multicultural communities and in younger people.

High community faecal carriage rates of CTX-M ESBL-producing Escherichia coli in a specific population group in Birmingham, UK.

OBJECTIVES: To determine the proportion of E. coli carrying specific CTX-M extended-spectrum ß-lactamase (ESBL) genotypes in a community population of East and North Birmingham. METHODS: General practice and outpatient stool samples from 732 individuals submitted for examination for faecal pathogens in 2010 were screened for ESBL-producing E. coli using chromogenic agar. Multiplex PCR, denaturing HPLC, DNA sequencing and PFGE were used to determine the CTX-M genotype and clonal subtype. Isolates from people were assigned to 'Europe', 'Middle East/South Asia' (MESA) or 'uncategorized' groups using software to determine probable global origin based on the subject's full name. RESULTS: Prevalence of CTX-M carriage in the sample population was 11.3%. There was a statistically significant difference (P < 0.001) between carriage in the Europe group (8.1%) and the MESA group (22.8%). There was also a higher rate of carriage of CTX-M-15-producing E. coli (P < 0.001) in MESA subjects. CONCLUSIONS: The high community carriage rate and the significant difference in carriage between the Europe and MESA subjects may have important consequences for therapy. If the rising trend in carriage of bacteria producing ESBLs continues, guidelines for empirical therapy for patients presenting from the community may need to be modified. The findings also raise the concern that the pattern and routes of spread of CTX-M-15 may be replicated in the future by broader-spectrum ß-lactamases, such as New Delhi metallo-ß-lactamase ('NDM-1').

Regional survey of CTX-M-type extended-spectrum ß-lactamases among Enterobacteriaceae reveals marked heterogeneity in the distribution of the ST131 clone.

OBJECTIVES: To establish the prevalence and diversity of clinically significant extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae harbouring bla(CTX-M) in the West Midlands region of the UK. METHODS: During a 2 month period, 370 consecutive, non-duplicate isolates were collected from 13 laboratories. Isolates were screened for the presence of bla(CTX-M) by multiplex PCR and genotyped using denaturing HPLC (DHPLC). Clonal relationships were studied by PFGE and O25b-ST131 Escherichia coli were identified by PCR. RESULTS: Two hundred and ninety-four out of 345 ESBL-producing isolates (85.2%) carried bla(CTX-M). CTX-M group 1 enzymes were expressed in 284 (96.6%) isolates, with the other 10 carrying group 9, 2 and 25/26 genes. All group 1 isolates had bla(CTX-M-15) DHPLC profiles. The bla(CTX-M) E. coli were split into 23 PFGE clusters. The largest cluster (RE1) was indistinguishable from the previously described strain A and all but one harboured bla(CTX-M-15.) A total of 66% of E. coli were O25b-ST131 positive. CONCLUSIONS: The CTX-M-15-producing RE1 clone (strain A) is the predominant clone in the West Midlands. This clone has spread throughout the region since its emergence in an outbreak 3 years earlier. Most, but not all, RE1 isolates belong to the O25b-ST131 lineage, providing further evidence that this lineage plays a pivotal role in the clonal dispersal of CTX-M-15-producing Enterobacteriaceae. Strain A was found to be considerably more heterogeneous than when first described and has acquired greater resistance to gentamicin. Approximately one-third of CTX-M producers represented a wide variety of unrelated strains. The study shows the rapid spread and diversification of CTX-M-producing Enterobacteriaceae over a 3 year period.

Reduction in the rate of methicillin-resistant Staphylococcus aureus acquisition in surgical wards by rapid screening for colonization: a prospective, cross-over study.

Identification of patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) and subsequent isolation and decolonization is pivotal to the control of cross infection in hospitals. The aim of this study was to establish if early identification of colonized patients using rapid methods alone reduces transmission. A prospective, cluster, two-period cross-over design was used. Seven surgical wards at a large hospital were allocated to two groups, and for the first 8 months four wards used rapid MRSA screening and three wards used a standard culture method. The groups were reversed for the second 8 months. Regardless of the method of detection, all patients were screened for nasal carriage on admission and then every 4 days. MRSA control measures remained constant. Results were analysed using a log linear Poisson regression model. A total of 12 682/13 952 patient ward episodes (PWE) were included in the study. Admission screening identified 453 (3.6%) MRSA-positive patient ward episodes, with a further 268 (2.2%) acquiring MRSA. After adjusting for other variables, rapid screening was shown to statistically reduce MRSA acquisition, with patients being 1.49 times (p 0.007) more likely to acquire MRSA in wards where they were screened using the culture method. Screening of surgical patients using rapid testing resulted in a statistically significant reduction in MRSA acquisition. This result was achieved in a routine surgical service with high bed occupancy and low availability of isolation rooms, making it applicable to the majority of health-care systems worldwide.

Epidemiological typing of meticillin-resistant Staphylococcus aureus isolates from Pakistan and India.

The levels of meticillin-resistant Staphylococcus aureus (MRSA) in Pakistan and India are known to be high, but few studies have described the epidemiology of the different MRSA clones present. In order to gain an understanding of the epidemiology of MRSA within this region, 60 MRSA isolates from Pakistan (49) and India (11) were genotyped. All isolates were typed using PFGE, staphylococcal interspersed repeat units (SIRUs), a restriction-modification method and staphylococcal cassette chromosome mec (SCCmec) typing. A subset of isolates that were distinct by PFGE and SIRUs were typed using multilocus sequence typing (MLST). Clonal complex (CC) 8 was the dominant clonal complex (57/60) and was present in both Pakistan and India. Within CC8, there were 10 SIRU profiles and 24 PFGE profiles. Two SIRU profiles were present in isolates from both India and Pakistan, whilst seven were distinct for Pakistan and one for India. All PFGE profiles were distinct for each of the two countries. Thirty-four of the 57 isolates carried SCCmec type III/IIIa and the remainder carried type IV SCCmec. MLST analysis of 14 CC8 isolates with diverse SIRU and PFGE profiles showed that all were single-locus variants, with nine belonging to sequence type (ST) 239, three to ST8 and two to ST113. From a single hospital in Pakistan, three isolates belonged to CC30 and all were indistinguishable by PFGE and SIRUs and carried the Panton-Valentine leukocidin gene. Thus, epidemiological typing of strains from three distinct locations in India and Pakistan revealed the predominance of one clonal complex and highly related STs. The ability of SIRUs and PFGE to differentiate within ST239 demonstrates their utility in defining local epidemiology in these countries.