Nosocomial or not? A combined epidemiological and genomic investigation to understand hospital-acquired COVID-19 infection on an elderly care ward.

BACKGROUND: COVID-19 has the potential to cause outbreaks in hospitals. Given the comorbid and elderly cohort of patients hospitalized, hospital-acquired COVID-19 infection is often fatal. Pathogen genome sequencing is becoming increasingly important in infection prevention and control (IPC). AIM: To inform the understanding of in-hospital SARS-CoV-2 transmission in order to improve IPC practices and to inform the future development of virological testing for IPC. METHODS: Patients detected COVID-19 positive by polymerase chain reaction on Ward A in April and May 2020 were included with contact tracing to identify other potential cases. Genome sequencing was undertaken for a subgroup of cases. Epidemiological, genomic, and cluster analyses were performed to describe the epidemiology and to identify factors contributing to the outbreak. FINDINGS: Fourteen cases were identified on Ward A. Contact tracing identified 16 further patient cases; in addition, eight healthcare workers (HCWs) were identified as being COVID-19 positive through a round of asymptomatic testing. Genome sequencing of 16 of these cases identified viral genomes differing by two single nucleotide polymorphisms or fewer, with further cluster analysis identifying two groups of infection (a five-person group and a six-person group). CONCLUSION: Despite the temporal relationship of cases, genome sequencing identified that not all cases shared transmission events. However, 11 samples were found to be closely related and these likely represented in-hospital transmission. This included three HCWs, thereby confirming transmission between patients and HCWs.

Arsenic bioaccessibility and speciation in clams and seaweed from a contaminated marine environment.

The bioaccessible concentration and speciation of arsenic (soluble in a gastrointestinal medium and available for absorption into the bloodstream) were determined in softshell clams (Mya arenaria), harvested by local residents until 2005, and in seaweed (Fucus sp.) from an arsenic-contaminated marine site in Seal Harbour, Nova Scotia, Canada. Bioaccessibility extractions to simulate the human gastrointestinal environment (pH 1.5 and glycine for 1h followed by pancreatin, bile extract and pH adjustment to 7 for an additional 4h) and speciation of arsenic in extracts (HPLC-HG-AAS to target inorganic arsenic species) and whole samples (XANES) were carried out. Total arsenic for the clams from the contaminated area ranged from 218 to 228 ppm wet weight, with a bioaccessible fraction of 34-46%, and the major bioaccessible species of arsenic were inorganic. The seaweed from the contaminated area contained 27-43 ppm wet weight total arsenic, with the bioaccessible fraction ranging from 63% to 81%, and inorganic arsenic was also predominant. The predominantly inorganic nature of arsenic in the whole samples was confirmed by XANES. In concurrence with the closure of the area for clam harvesting, the clams and seaweed from Seal Harbour should probably not be used for human consumption.

Escherichia coli O157: occurrence, transmission and laboratory detection.

The steady increase in the number of reported cases of Escherichia coli O157 infection is attributable to the proliferation of the organism, and to improved clinical and laboratory awareness. E. coli O157 is responsible for sporadic cases and outbreaks of diarrhoea, haemorrhagic colitis, haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura. The pathogenesis of the organism is not fully understood, and the main virulence factors are thought to be the production of 'Shiga-like' toxin and adherence to intestinal mucosal cells. The majority of outbreaks have taken place in north America, Canada and the United Kingdom. The most important source of E. coli O157 infection is under-cooked ground beef and other bovine products. The infectious dose is low, person-to-person spread can occur, and direct transmission between calves and humans has been demonstrated. Infection has been acquired following contact with livestock at farm visitor centres. All diarrhoeal stools received in the laboratory should be examined for E. coli by culture and toxin detection methods. The presence of 'Shiga-like' toxin can be detected by demonstrating cytotoxicity, dot blotting, the polymerase chain reaction or by enzyme-linked immunosorbent assay. Serological techniques are useful in aiding and supporting a diagnosis. Contamination of meat by E. coli O157 probably occurs at slaughter or during processing, therefore, to prevent infection it is important to emphasise the dangers associated with the consumption of under-cooked beef products.

Teamwork: bringing order out of chaos.

The staff of one medical/surgical unit defined nine qualities of a winning team, then set about to turn their unit around. The situation faced by the unit nurses, technicians, secretaries and the nurse manager as well as the successful strategies they implemented to enhance teamwork are presented.

Evaluation of a 'one tube' reverse transcription-polymerase chain reaction for the detection of ruminant pestiviruses.

A 'one tube' reverse transcription-polymerase chain reaction ('one tube' RT-PCR) using rTth DNA polymerase was compared with an existing RT-PCR using Taq DNA polymerase (Taq RT-PCR) to detect ruminant pestiviruses in infected cell cultures. The technically simpler and more convenient 'one tube' method was relatively insensitive detecting only 11 of the 34 samples tested, all of which were positive by Taq RT-PCR.

Effect of Medicare prospective payment system on a home health agency: changes in patient population and services provided.

Data from a large home health agency was retrospectively reviewed to determine the effect of Medicare's Diagnosis Related Group (DRG) payment system on posthospital care. Variables included demographics, diagnoses, functional ability, frequency and type of services provided, and discharge status. An increase in the provision of rehabilitation and nursing services provided in the post-DRG population was found. No negative effects on patient outcomes, such as increases in emergency room visits, rehospitalization, or death, were found.

Villous adenomas of the duodenum and an unusual variant.

We report two cases of villous adenoma of the duodenum, one arising from the main papilla and the other from the accessory papilla. Both were managed by local resection. In one case endoscopic biopsies and intraoperative frozen sections were negative for carcinoma but histology of the locally resected specimen revealed a focus of invasive adenocarcinoma. Villous adenomas of the duodenum have a high risk of malignant change and foci of carcinoma can be missed on endoscopic biopsy. The literature is reviewed and the clinical, diagnostic, pathological and therapeutic aspects of villous adenomas of the duodenum are discussed.

Evaluation of cultural techniques for isolating Campylobacter pyloridis from endoscopic biopsies of gastric mucosa.

One hundred and three gastroscopic biopsies from 80 patients were cultured for Campylobacter pyloridis and studied histologically. Active chronic gastritis, as shown by the presence of polymorphonuclear leucocytes, was diagnosed in 51 biopsies and C pyloridis was found in 47. Sixteen gastric biopsies showed normal histology (no inflammation); C pyloridis was detected in only one of these, and a second biopsy taken from this patient at the same time showed active gastritis. Biopsies could be kept at 4 degrees C for five hours without loss of viability of C pyloridis. An inoculum made by grinding the biopsy in a ground glass grinder consistently gave a much heavier growth of C pyloridis than one made by mincing the specimen. The campylobacter supplement ferrous sulphate, sodium metabisulphite, sodium pyruvate (FBP) (Oxoid) was inhibitory for some isolates; the inhibitory component was found to be sodium metabisulphite. Contaminants, but not C pyloridis, were inhibited by the incorporation of vancomycin 6 mg/l, nalidixic acid 20 mg/l, and amphotericin 2 mg/l, but higher concentrations inhibited C pyloridis. Undried plates kept in a plastic container at room temperature for up to two weeks were as satisfactory as freshly poured plates for the isolation of C pyloridis.

Nasal mucosal involvement in ulcerative colitis.

A patient with ulcerative colitis, sclerosing cholangitis, and mouth ulceration, developed an unusual lesion involving the nasal mucosa. This was thought to represent another extra-intestinal manifestation of inflammatory bowel disease.

Acquired postganglionic cholinergic dysautonomia: case report and review of the literature.

An 8-year-old girl with acute abdominal pain had cholinergic autonomic dysfunction. There have been only four patients with acquired postganglionic cholinergic dysautonomia described in the literature. The characteristic clinical features are atony of the bowel and bladder, lack of tears, saliva, and sweat, internal ophthalmoplegia, and normal adrenergic functions. Special studies for autonomic nervous function help in confirming this diagnosis. The exact pathogenesis of the disorder is still not clear. This case demonstrates successful treatment with bethanechol chloride.

Identification of specific hemoglobins within individual erythrocytes.

The identification of specific antibodies for a variety of inherited hemoglobin variants presents the opportunity to develop sensitive immunochemical measurement techniques for such variants. In this study antibodies specific for human hemoglobins A1 and S were isolated from immune rabbit serum. These were labeled with either fluoroscein isothiocyanate or tetramethylrhodamine isothiocyanate. Erythrocytes suspended in agar were incubated with these labeled antibodies and hemoglobins A1, S, and F were identified within individual cells by fluorescence microscopy. This capability offers potential for more specific investigation into heterogenous distribution of specific hemoglobins within an erythroycte or bone marrow cell population and for developing a sensitive technique applicable to antenatal diagnosis of specific hemoglobinopathies.