Residents of long-term care facilities (LTCFs) were disproportionately affected by the COVID-19 pandemic. We assessed the extent to which hospital-associated infections contributed to COVID-19 LTCF outbreaks in England. We matched addresses of cases between March 2020 and June 2021 to reference databases to identify LTCF residents. Linkage to health service records identified hospital-associated infections, with the number of days spent in hospital before positive specimen date used to classify these as definite or probable. Of 149,129 cases in LTCF residents during the study period, 3,748 (2.5%) were definite or probable hospital-associated and discharged to an LTCF. Overall, 431 (0.3%) were identified as index cases of potentially nosocomial-seeded outbreaks (2.7% (431/15,797) of all identified LTCF outbreaks). These outbreaks involved 4,521 resident cases and 1,335 deaths, representing 3.0% and 3.6% of all cases and deaths in LTCF residents, respectively. The proportion of outbreaks that were potentially nosocomial-seeded peaked in late June 2020, early December 2020, mid-January 2021, and mid-April 2021. Nosocomial seeding contributed to COVID-19 LTCF outbreaks but is unlikely to have accounted for a substantial proportion. The continued identification of such outbreaks after the implementation of preventative policies highlights the challenges of preventing their occurrence.

Nosocomial transmission of COVID-19 among immunocompromised hosts can have a serious impact on COVID-19 severity, underlying disease progression and SARS-CoV-2 transmission to other patients and healthcare workers within hospitals. We experienced a nosocomial outbreak of COVID-19 in the setting of a daycare unit for paediatric and young adult cancer patients. Between 9 and 18 November 2020, 473 individuals (181 patients, 247 caregivers/siblings and 45 staff members) were exposed to the index case, who was a nursing staff. Among them, three patients and four caregivers were infected. Two 5-year-old cancer patients with COVID-19 were not severely ill, but a 25-year-old cancer patient showed prolonged shedding of SARS-CoV-2 RNA for at least 12 weeks, which probably infected his mother at home approximately 7–8 weeks after the initial diagnosis. Except for this case, no secondary transmission was observed from the confirmed cases in either the hospital or the community. To conclude, in the day care setting of immunocompromised children and young adults, the rate of in-hospital transmission of SARS-CoV-2 was 1.6% when applying the stringent policy of infection prevention and control, including universal mask application and rapid and extensive contact investigation. Severely immunocompromised children/young adults with COVID-19 would have to be carefully managed after the mandatory isolation period while keeping the possibility of prolonged shedding of live virus in mind.

The Middle East respiratory syndrome coronavirus (MERS-CoV) is caused by a novel coronavirus discovered in 2012. Since then, 1806 cases, including 564 deaths, have been reported by the Kingdom of Saudi Arabia (KSA) and affected countries as of 1 June 2016. Previous literature attributed increases in MERS-CoV transmission to camel breeding season as camels are likely the reservoir for the virus. However, this literature review and subsequent analysis indicate a lack of seasonality. A retrospective, epidemiological cluster analysis was conducted to investigate increases in MERS-CoV transmission and reports of household and nosocomial clusters. Cases were verified and associations between cases were substantiated through an extensive literature review and the Armed Forces Health Surveillance Branch's Tiered Source Classification System. A total of 51 clusters were identified, primarily nosocomial (80·4%) and most occurred in KSA (45·1%). Clusters corresponded temporally with the majority of periods of greatest incidence, suggesting a strong correlation between nosocomial transmission and notable increases in cases.

This study aimed to identify risk factors for dogs becoming rectal carriers of multidrug-resistant (MDR) Escherichia coli while hospitalized in a veterinary teaching hospital. Exposures to potential risk factors, including treatments, hospitalization, and interventions during a 42-day pre-admission period and hospitalization variables, were assessed for 90 cases and 93 controls in a retrospective, risk-based, case-control study. On multivariable analyses, hospitalization for >6 days [odds ratio (OR) 2·91–8·00], treatment with cephalosporins prior to admission (OR 5·04, 95% CI 1·25–20·27), treatment with cephalosporins for >1 day (OR 5·18, 95% CI 1·86–14·41), and treatment with metronidazole (OR 7·17, 95% CI 1·01–50·79) while hospitalized were associated with increased risk of rectal carriage of MDR E. coli during hospitalization. The majority of rectal isolates obtained during the study period conformed to MDR E. coli clonal groups previously obtained from extraintestinal infections. These results can assist the development of improved infection control guidelines for the management of dogs in veterinary hospitals to prevent the occurrence of nosocomial clinical infections.

We report a nosocomial outbreak of Crimean-Congo haemorrhagic fever (CCHF) that affected six patients in June 2009 in Ghaem Hospital, Mashhad, Iran, apparently related to one index case. The last four cases were healthcare workers. Infection was spread by percutaneous exposure to two cases, and probably by direct contact with blood, clothes and sheets, to three others. The diagnosis in the two fatal cases was not confirmed virologically. The diagnosis in four cases who survived was confirmed by specific reverse transcription polymerase chain reaction. The patients were treated with ribavirin. In endemic areas, every patient presenting with a febrile haemorrhagic syndrome should be considered to have a viral haemorrhagic fever until proven otherwise. Patients who meet the criteria for probable CCHF should be admitted to hospital and treated with ribavirin. Appropriate isolation precautions should be immediately initiated.

The incidence of nosocomial candidaemia was evaluated in a retrospective study in a Turkish tertiary-care hospital. Over a 12-year period (1996–2007), a total of 743 episodes of candidaemia occurred in 743 patients, accounting for an average incidence of 1·9 episodes/1000 admissions and 2·9 episodes/10 000 patient-days per year. The annual incidence was almost constant during the study period except for 1996 when it was significantly higher in comparison with other years (P<0·05). The most common species isolated was Candida albicans (45%), followed by C. parapsilosis (26%), C. tropicalis (7%), C. krusei (7%), and C. glabrata (3·5%). A significant increase in C. albicans isolates causing candidaemia linked to a decrease in C. parapsilosis isolates in adult patients and C. krusei isolates in children was found between the two 6-year study periods. This trend reflects improved infection control at Uludağ University Hospital. Ninety percent of isolates were susceptible to fluconazole (⩽8 μg/ml) and resistance was found only in C. glabrata and C. parapsilosis isolates. Regular local surveillance of Candida spp. is important in order to develop empirical treatment protocols to reduce the incidence and mortality of candidaemia.

Circulation of methicillin-resistant Staphylococcus aureus (MRSA) outside hospitals could alter the impact of hospital-based control strategies. We investigated two groups of cases (each matched to controls with MRSA): 61 ‘community cases’ not in acute hospital in the year before MRSA isolation; and 21 cases with ciprofloxacin-sensitive (CipS) MRSA. Multi-locus sequence typing, spa-typing and Panton–Valentine leukocidin gene testing were performed and demographics obtained. Additional questionnaires were completed by community case GPs. Community cases comprised 6% of Oxfordshire MRSA. Three community cases had received no regular healthcare or antibiotics: one was infected with CipS. Ninety-one percent of community cases had healthcare-associated sequence type (ST)22/36; CipS MRSA cases had heterogeneous STs but many had recent healthcare exposure. A substantial minority of UK MRSA transmission may occur outside hospitals. Hospital strains are becoming ‘feral’ or persisting in long-term carriers in the community with regular healthcare contacts; those with recent healthcare exposure may nevertheless acquire non-hospital epidemic MRSA strains in the community.

We analysed nosocomial MRSA cases between January 2004 and December 2006 in a retrospective case-control study in a 250-bed tertiary-care teaching hospital. During the study period, 265 nosocomial Staphylococcus aureus infections were identified in 231 patients. There was a significant increase in methicillin resistance in isolates (MRSA) from these infections with frequencies for 2004 of 39/88 (44·3%), 2005 (62/80, 77·5%), and 2006 (75/97, 77·3%) (P<0·001). Multivariate analysis showed that associated factors for nosocomial MRSA infection were prolonged hospitalization (OR 3·982, 95% CI 2·235–7·094, P<0·001), mechanical ventilation (OR 3·052, 95% CI 1·666–5·590, P<0·001), surgical operation (OR 2·032, 95% CI 1·102–3·748, P=0·023), and male sex (OR 2·000, 95% CI 1·081–3·699, P=0·027). The determination of associated factors for methicillin resistance in nosocomial S. aureus infections in hospitals will play an important role in efforts to reduce MRSA infection rates.