Epidemiologic and Genomic Analysis of SARS-CoV-2 Delta Variant Superspreading Event in Nightclub, the Netherlands, June 2021.

We report a severe acute respiratory syndrome coronavirus 2 superspreading event in the Netherlands after distancing rules were lifted in nightclubs, despite requiring a negative test or vaccination. This occurrence illustrates the potential for rapid dissemination of variants in largely unvaccinated populations under such conditions. We detected subsequent community transmission of this strain.

Implementation of a national testing policy in Dutch nursing homes during SARS-CoV-2 outbreaks.

BACKGROUND: To evaluate how a national policy of testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) regardless of symptoms was implemented during outbreaks in Dutch nursing homes in the second wave of the pandemic and to explore barriers and facilitators to serial testing. METHODS: We conducted a mixed-method study of nursing homes in the Netherlands with a SARS-CoV-2 outbreak after 15 September 2020. Direct care staff and management from 355 healthcare organizations were invited to participate in a digital survey. A total of 74 out of 355 (20.9%) healthcare organizations participated and provided information about 117 nursing homes. We conducted 26 in-depth interviews on the outbreak and the testing strategy used. We also conducted four focus group meetings involving managers, physicians, nurses, and certified health assistants. Recordings were transcribed and data were thematically analyzed. RESULTS: One hundred and four nursing homes (89%) tested residents regardless of their symptoms during the outbreak, and 85 nursing homes (73%) tested the staff regardless of their symptoms. However, interviews showed testing was sometimes implemented during later stages of the outbreak and was not always followed up with serial testing. Barriers to serial testing regardless of symptoms were lack of knowledge of local leaders with decisional making authority, lack of a cohort ward or skilled staff, and insufficient collaboration with laboratories or local public health services. Important facilitators to serial testing were staff willingness to undergo testing and the availability of polymerase chain reaction (PCR) tests. CONCLUSIONS: Serial testing regardless of symptoms was only partially implemented. The response rate of 21% of nursing home organizations gives a risk of selection bias. Barriers to testing need to be addressed. A national implementation policy that promotes collaboration between public health services and nursing homes and educates management and care staff is necessary.

Use of a Telemedicine Team to Improve Guideline-Based Antibiotic Prescribing.

OBJECTIVES: Assessing the impact of a virtual antibiotic team (VAT) on appropriateness of antibiotic prescribing behavior of older care physicians, regarding urinary tract (UTI), respiratory tract (RTI), and skin and soft tissue infections (SSTI), in residents of long-term care facilities (LTCF). DESIGN: Before-after trial; introduction of a VAT consisting of a clinical microbiologist, older care physician, and a pharmacist. SETTING AND PARTICIPANTS: Eight LTCFs in Amsterdam, the Netherlands. METHODS: The VAT was introduced on April 1, 2019. Meetings were held via weekly teleconferencing. VAT advised about treatment indication, antibiotic choice, and additional diagnostics. Data were retrospectively extracted from resident files regarding infection episodes for which antibiotics had been prescribed during 12 months before (period I) and 11 months after VAT introduction (period II). Appropriateness of antibiotic prescriptions was assessed using national guidelines and an algorithm developed for antimicrobial stewardship in nursing homes. Antibiotic prescription rates per 100 person-years (py) were estimated and compared between periods using incidence rate ratio (IRR) with 95% confidence intervals (CIs). Proportions of appropriate antibiotic prescriptions were compared between periods using the chi-squared test. RESULTS: A total of 524 infection episodes for which antibiotics were prescribed were identified: 284 in period I and 240 in period II. Antibiotic prescription rates before VAT introduction were 73 per 100 py in period I and decreased to 68 in period II (IRR 0.9, 95% CI 0.8-1.1). Of all prescriptions, 23.9% were assessed as appropriate during period I, which increased to 40.4% in period II (P < .001). Appropriate antibiotic use increased after VAT introduction for RTI (12.5% to 48.2%, P < .001) and SSTI (47.5% to 74.3%, P = .02) but remained similar for UTI (23.5% to 28.8%, P = .29). CONCLUSIONS AND IMPLICATIONS: After implementation of VAT in LTCFs, appropriate antibiotic use increased significantly overall, and for RTI and SSTI particularly. Improving prescribing behavior regarding UTI might need extra strategies.

An unusual outbreak in the Netherlands: community-onset impetigo caused by a meticillin-resistant Staphylococcus aureus with additional resistance to fusidic acid, June 2018 to January 2020.

In this retrospective observational study, we analysed a community outbreak of impetigo with meticillin-resistant Staphylococcus aureus (MRSA), with additional resistance to fusidic acid (first-line treatment). The outbreak occurred between June 2018 and January 2020 in the eastern part of the Netherlands with an epidemiological link to three cases from the north-western part. Forty nine impetigo cases and eight carrier cases were identified, including 47 children. All but one impetigo case had community-onset of symptoms. Pharmacy prescription data for topical mupirocin and fusidic acid and GP questionnaires suggested an underestimated outbreak size. The 57 outbreak isolates were identified by the Dutch MRSA surveillance as MLVA-type MT4627 and sequence type 121, previously reported only once in 2014. Next-generation sequencing revealed they contained a fusidic acid resistance gene, exfoliative toxin genes and an epidermal cell differentiation inhibitor gene. Whole-genome multilocus sequence typing revealed genetic clustering of all 19 sequenced isolates from the outbreak region and isolates from the three north-western cases. The allelic distances between these Dutch isolates and international isolates were high. This outbreak shows the appearance of community-onset MRSA strains with additional drug resistance and virulence factors in a country with a low prevalence of antimicrobial resistance.

Are presymptomatic SARS-CoV-2 infections in nursing home residents unrecognised symptomatic infections? Sequence and metadata from weekly testing in an extensive nursing home outbreak.

BACKGROUND: Sars-CoV-2 outbreaks resulted in a high case fatality rate in nursing homes (NH) worldwide. It is unknown to which extent presymptomatic residents and staff contribute to the spread of the virus. AIMS: To assess the contribution of asymptomatic and presymptomatic residents and staff in SARS-CoV-2 transmission during a large outbreak in a Dutch NH. METHODS: Observational study in a 185-bed NH with two consecutive testing strategies: testing of symptomatic cases only, followed by weekly facility-wide testing of staff and residents regardless of symptoms. Nasopharyngeal and oropharyngeal testing with RT-PCR for SARs-CoV-2, including sequencing of positive samples, was conducted with a standardised symptom assessment. RESULTS: 185 residents and 244 staff participated. Sequencing identified one cluster. In the symptom-based test strategy period, 3/39 residents were presymptomatic versus 38/74 residents in the period of weekly facility-wide testing (P-value < 0.001). In total, 51/59 (91.1%) of SARS-CoV-2 positive staff was symptomatic, with no difference between both testing strategies (P-value 0.763). Loss of smell and taste, sore throat, headache or myalga was hardly reported in residents compared to staff (P-value <0.001). Median Ct-value of presymptomatic residents was 21.3, which did not differ from symptomatic (20.8) or asymptomatic (20.5) residents (P-value 0.624). CONCLUSIONS: Symptoms in residents and staff are insufficiently recognised, reported or attributed to a possible SARS-CoV-2 infection. However, residents without (recognised) symptoms showed the same potential for viral shedding as residents with symptoms. Weekly testing was an effective strategy for early identification of SARS-Cov-2 cases, resulting in fast mitigation of the outbreak.