Secondary attack rates of COVID-19 in Norwegian families: a nation-wide register-based study.

To characterize the family index case for detected SARS-CoV-2 and describe testing and secondary attack rates in the family, we used individual-level administrative data of all families and all PCR tests for SARS-CoV-2 in Norway in 2020. All families with at least one parent and one child below the age of 20 who lived at the same address (N = 662,582), where at least one member, i.e. the index case, tested positive for SARS-CoV-2 in 2020, were included. Secondary attack rates (SAR7) were defined as the share of non-index family members with a positive PCR test within 7 days after the date when the index case tested positive. SARs were calculated separately for parent- and child-index cases, and for parent- and child-secondary cases. We identified 7548 families with an index case, comprising 26,991 individuals (12,184 parents, 14,808 children). The index was a parent in 66% of the cases. Among index children, 42% were in the age group 17-20 and only 8% in the age group 0-6. When the index was a parent, SAR7 was 24% (95% CI 24-25), whilst SAR7 was 14% (95% CI 13-15) when the index was a child. However, SAR7 was 24% (95% CI 20-28) when the index was a child aged 0-6 years and declined with increasing age of the index child. SAR7 from index parent to other parent was 35% (95% CI 33-36), and from index child to other children 12% (95% CI 11-13). SAR7 from index child aged 0-6 to parents was 27% (95% CI 22-33). The percent of non-index family members tested within 7 days after the index case, increased from about 20% in April to 80% in December, however, SAR7 stabilized at about 20% from May. We conclude that parents and older children are most often index cases for SARS-CoV-2 in families in Norway, while parents and young children more often transmit the virus within the family. This study suggests that whilst the absolute infection numbers are low for young children because of their low introduction rate, when infected, young children and parents transmit the virus to the same extent within the family.

MRSA prevalence among healthcare personnel in contact tracings in hospitals. / MRSA-forekomst blant helsepersonell ved smitteoppsporing i sykehus.

BAKGRUNN: I norsk helsevesen gjennomføres omfattende tiltak for å hindre spredning av meticillinresistente Staphylococcus aureus (MRSA). Vi ønsket å undersøke hvor mange smitteoppsporinger som gjøres rundt nyoppdagede MRSA-tilfeller hos pasienter og ansatte i sykehus, og hvor ofte smitteoppsporingene fører til ytterligere funn hos helsepersonell. MATERIALE OG METODE: I denne retrospektive observasjonsstudien bidro smittevernenhetene ved åtte helseforetak i landets fire helseregioner med opplysninger om MRSA-funn hos helsepersonell etter gjennomførte MRSA-smitteoppsporinger. Data ble innhentet fra 14 ulike somatiske sykehus i årene 2012-15. RESULTATER: 10 142 ansatte i helsevesenet ble testet for MRSA, med positivt funn hos 31 ansatte (0,31 %). Hos 19 ansatte (0,19 %) ble det påvist samme MRSA-stamme som hos indekskasus. I kun to av 351 smitteoppsporinger (0,57 %) ble samme MRSA-stamme funnet hos mer enn én ansatt. FORTOLKNING: MRSA-smitteoppsporing i norske sykehus har et betydelig omfang, men det er sjelden det påvises MRSA hos helsepersonell i forbindelse med smitteoppsporing.

A comparison of extended spectrum ß-lactamase producing Escherichia coli from clinical, recreational water and wastewater samples associated in time and location.

Extended spectrum ß-lactamase producing Escherichia coli (ESBL-EC) are excreted via effluents and sewage into the environment where they can re-contaminate humans and animals. The aim of this observational study was to detect and quantify ESBL-EC in recreational water and wastewater, and perform a genetic and phenotypic comparative analysis of the environmental strains with geographically associated human urinary ESBL-EC. Recreational fresh- and saltwater samples from four different beaches and wastewater samples from a nearby sewage plant were filtered and cultured on differential and ESBL-selective media. After antimicrobial susceptibility testing and multi-locus variable number of tandem repeats assay (MLVA), selected ESBL-EC strains from recreational water were characterized by whole genome sequencing (WGS) and compared to wastewater and human urine isolates from people living in the same area. We detected ESBL-EC in recreational water samples on 8/20 occasions (40%), representing all sites. The ratio of ESBL-EC to total number of E. coli colony forming units varied from 0 to 3.8%. ESBL-EC were present in all wastewater samples in ratios of 0.56-0.75%. ST131 was most prevalent in urine and wastewater samples, while ST10 dominated in water samples. Eight STs and identical ESBL-EC MLVA-types were detected in all compartments. Clinical ESBL-EC isolates were more likely to be multidrug-resistant (p<0.001). This study confirms that ESBL-EC, including those that are capable of causing human infection, are present in recreational waters where there is a potential for human exposure and subsequent gut colonisation and infection in bathers. Multidrug-resistant E. coli strains are present in urban aquatic environments even in countries where antibiotic consumption in both humans and animals is highly restricted.

Fecal carriage of extended spectrum ß-lactamase producing Escherichia coli and Klebsiella pneumoniae after urinary tract infection - A three year prospective cohort study.

We have performed a prospective cohort study to investigate the duration of and risk factors for prolonged fecal carriage of ESBL-producing Escherichia coli or Klebsiella pneumoniae in patients with community acquired urinary tract infection caused by these bacteria. From 2009 to 2011, 101 Norwegian patients were recruited. Stool swabs and questionnaires were collected every three months for one year and at the end of the study in 2012. Information on antibiotic prescriptions was collected from the Norwegian Prescription Database. Stool samples were cultured directly on ChromID ESBL agar as well as in an enrichment broth, and culture positive isolates were examined by blaCTX-M multiplex PCR. Isolates without blaCTX-M were investigated for alternative ESBL-determinants with a commercial microarray system. Time to fecal clearance of ESBL producing Enterobacteriaceae was also analysed using Kaplan-Meier estimates. Uni- and multivariate logistic regression was used to compare groups according to previously described risk factors. The ESBL point prevalence of fecal carriage were 61% at 4 months, 56% at 7 months, 48% at 10 months, 39% at 13 months, 19% after two years, and 15% after three years or more. We found no correlation between duration of carriage, comorbidity, antibiotic use or travel to ESBL high-prevalence countries. Prolonged carriage was associated with E. coli isolates of phylogroup B2 or D. Importantly, comparative MLST and MLVA analyses of individual paired urine and fecal E. coli isolates revealed that ESBL production commonly occurred in diverse strains within the same host. When investigating cross-transmission of ESBL producing bacteria in health care institutions, this notion should be taken into account.