Healthcare-acquired clusters of COVID-19 across multiple wards in a Scottish health board.

BACKGROUND: Healthcare-acquired COVID-19 has been an additional burden on hospitals managing increasing numbers of patients with SARS-CoV-2. One acute hospital (W) among three in a Scottish healthboard experienced an unexpected surge of COVID-19 clusters. AIM: To investigate possible causes of COVID-19 clusters at Hospital W. METHODS: Daily surveillance provided total numbers of patients and staff involved in clusters in three acute hospitals (H, M and W) and care homes across the healthboard. All clusters were investigated and documented, along with patient boarding, community infection rates and outdoor temperatures from October 2020 to March 2021. Selected SARS-CoV-2 strains were genotyped. FINDINGS: There were 19 COVID-19 clusters on 14 wards at Hospital W during the six-month study period, lasting from two to 42 days (average, five days; median, 14 days) and involving an average of nine patients (range 1-24) and seven staff (range 0-17). COVID-19 clusters in Hospitals H and M reflected community infection rates. An outbreak management team implemented a control package including daily surveillance; ward closures; universal masking; screening; restricting staff and patient movement; enhanced cleaning; and improved ventilation. Forty clusters occurred across all three hospitals before a January window-opening policy, after which there were three during the remainder of the study. CONCLUSION: The winter surge of COVID-19 clusters was multi-factorial, but clearly exacerbated by moving trauma patients around the hospital. An extended infection prevention and control package including enhanced natural ventilation helped reduce COVID-19 clusters in acute hospitals.

Legionella longbeachae serogroup 1 infections linked to potting compost.

Four cases of legionellosis caused by Legionella longbeachae serogroup (sg) 1 were identified in Scotland from 2008 to 2010. All case patients had exposure to commercially manufactured growing media or potting soils, commonly known as multipurpose compost (MPC), in greenhouse conditions, prior to disease onset. Two patients had been using the same brand of MPC but the clinical isolates were distinct genotypically by amplified fragment length polymorphism (AFLP) analysis. However, an indistinguishable AFLP profile was also found in an environmental isolate from the supply of MPC used by each patient. The third patient was diagnosed by immunofluorescent antibody serology only; however, the MPC to which this patient was exposed contained L. longbeachae sg 1 in large quantities (80 000 c.f.u. g(-1)). The fourth patient was L. longbeachae sg 1 culture-positive, but L. longbeachae was not identified from 10 samples of garden composting material. As compost is commonly used, but L. longbeachae infection seemingly rare, further work is required to ascertain (i) the prevalence and predictors of L. longbeachae in compost and (ii) the conditions which facilitate transmission and generate an aerosol of the bacteria. As most cases of legionellosis are diagnosed by urinary antigen that is Legionella pneumophila-specific and does not detect infection with L. longbeachae, patients in cases of community-acquired pneumonia with a history of compost exposure should have serum and respiratory samples sent to a specialist Legionella reference laboratory for analysis.

A cluster of Legionnaires' disease caused by Legionella longbeachae linked to potting compost in Scotland, 2008-2009.

Three cases of Legionnaires disease caused by Legionella longbeachae Sg 1 associated with potting compost have been reported in Scotland between 2008 and 2009. The exact method of transmission is still not fully understood as Legionnaires disease is thought to be acquired by droplet inhalation. The linked cases associated with compost exposure call for an introduction of compost labelling, as is already in place in other countries where L. longbeachae outbreaks have been reported.