Rapid detection of the source of a Listeria monocytogenes outbreak in Switzerland through routine interviewing of patients and whole-genome sequencing.

AIMS OF THE STUDY: Listeriosis is a notifiable disease in Switzerland. In summer 2022, the Swiss Federal Office of Public Health noticed an increase in reports of listeriosis cases, indicating a possible ongoing outbreak. Here we present the approaches applied for rapidly confirming the outbreak, detecting the underlying source of infection and the measures put in place to eliminate it and contain the outbreak. METHODS: For close surveillance and early detection of outbreak situations with their possible sources, listeriosis patients in Switzerland are systematically interviewed about risk behaviours and foods consumed prior to the infection. Listeria monocytogenes isolates derived from patients in medical laboratories are sent to the National Reference Laboratory for Enteropathogenic Bacteria and Listeria, where they routinely undergo whole-genome sequencing. Interview and whole-genome sequencing data are continuously linked for comparison and analysis. RESULTS: In summer 2022, 20 patient-derived L. monocytogenes serotype 4b sequence type 388 strains were found to belong to an outbreak cluster (≤10 different alleles between neighbouring isolates) based on core genome multilocus sequence typing analysis. Geographically, 18 of 20 outbreak cases occurred in northeastern Switzerland. The median age of patients was 77.4 years (range: 58.1-89.7), with both sexes equally affected. Rolling analysis of the interview data revealed smoked trout from a local producer as a suspected infection source, triggering an on-site investigation of the production facility and sampling of the suspected products by the responsible cantonal food inspection team on 15 July 2022. Seven of ten samples tested positive for L. monocytogenes and the respective cantonal authority ordered a ban on production and distribution as well as a product recall. The Federal Food Safety and Veterinary Office released a nationwide public alert covering the smoked fish products concerned. Whole-genome sequencing analysis confirmed the interrelatedness of the L. monocytogenes smoked trout product isolates and the patient-derived isolates. Following the ban on production and distribution and the product recall, reporting of new outbreak-related cases rapidly dropped to zero. CONCLUSIONS: This listeriosis outbreak could be contained within a relatively short time thanks to identification of the source of contamination through the established combined approach of timely interviewing of every listeriosis patient or a representative and continuous molecular analysis of the patient- and food-derived L. monocytogenes isolates. These findings highlight the effectiveness of this well-established, joint approach involving the federal and cantonal authorities and the research institutions mandated to contain listeriosis outbreaks in Switzerland.

Assessing the association between air pollution and child development in São Paulo, Brazil.

BACKGROUND: Outdoor air pollution is increasingly recognised as a key threat to population health globally, with particularly high risks for urban residents. In this study, we assessed the association between residential nitrogen dioxide (NO2) exposure and children's cognitive and behavioural development using data from São Paulo Brazil, one of the largest urban agglomerations in the world. METHODS: We used data from the São Paulo Western Region Birth Cohort, a longitudinal cohort study aiming to examine determinants as well as long-term implications of early childhood development. Cross-sectional data from the 72-month follow-up was analysed. Data on NO2 concentration in the study area was collected at 80 locations in 2019, and land use regression modelling was used to estimate annual NO2 concentration at children's homes. Associations between predicted NO2 exposure and children's cognitive development as well as children's behavioural problems were estimated using linear regression models adjusted for an extensive set of confounders. All results were expressed per 10 µg/m3 increase in NO2. RESULTS: 1143 children were included in the analysis. We found no association between NO2 and children's cognitive development (beta -0.05, 95% CI [-0.20; 0.10]) or behavioural problems (beta 0.02, 95% CI [-0.80; 0.12]). CONCLUSION: No association between child cognition or child behaviour and NO2 was found in this cross-sectional analysis. Further research will be necessary to understand the extent to which these null results reflect a true absence of association or other statistical, biological or adaptive factors not addressed in this paper.

Association between community noise and children's cognitive and behavioral development: A prospective cohort study.

BACKGROUND: Noise exposure has been associated with adverse cognitive and behavioral outcomes in children, but evidence on longitudinal associations between community noise and child development in low- and middle-income countries is rare. We investigated associations between community noise and behavioral and cognitive development in preschool children in São Paulo. METHODS: We linked child development data from the São Paulo Western Region Birth Cohort with average (Lden) and night-time (Lnight) community noise exposure at children's home, estimated by means of a land use regression model using various predictors (roads, schools, greenness, residential and informal settlements). Outcomes were the Strengths and Difficulties Questionnaire (SDQ) and Regional Project on Child Development Indicators (PRIDI) at 3 years of age and the Child Behavior Checklist (CBCL) and International Development and Early Learning Assessment (IDELA) at 6 years of age. We investigated the relationship between noise exposure and development using cross-sectional and longitudinal regression models. RESULTS: Data from 3385 children at 3 years of age and 1546 children at 6 years of age were analysed. Mean Lden and Lnight levels were 70.3 dB and 61.2 dB, respectively. In cross-sectional analyses a 10 dB increase of Lden above 70 dB was associated with a 32% increase in the odds of borderline or abnormal SDQ total difficulties score (OR = 1.32, 95% CI: 1.04; 1.68) and 0.72 standard deviation (SD) increase in the CBCL total problems z-score (95% CI: 0.55; 0.88). No cross-sectional association was found for cognitive development. In longitudinal analyses, each 10 dB increase was associated with a 0.52 SD increase in behavioral problems (95% CI: 0.28; 0.77) and a 0.27 SD decrease in cognition (95%-CI: 0.55; 0.00). Results for Lnight above 60 dB were similar. DISCUSSION: Our findings suggest that community noise exposure above Lden of 70 dB and Lnight of 60 dB may impair behavioral and cognitive development of preschool children.

Land use regression modelling of community noise in São Paulo, Brazil.

Noise pollution has negative health consequences, which becomes increasingly relevant with rapid urbanization. In low- and middle-income countries research on health effects of noise is hampered by scarce exposure data and noise maps. In this study, we developed land use regression (LUR) models to assess spatial variability of community noise in the Western Region of São Paulo, Brazil.We measured outdoor noise levels continuously at 42 homes once or twice for one week in the summer and the winter season. These measurements were integrated with various geographic information system variables to develop LUR models for predicting average A-weighted (dB(A)) day-evening-night equivalent sound levels (Lden) and night sound levels (Lnight). A supervised mixed linear regression analysis was conducted to test potential noise predictors for various buffer sizes and distances between home and noise source. Noise exposure levels in the study area were high with a site average Lden of 69.3 dB(A) ranging from 60.3 to 82.3 dB(A), and a site average Lnight of 59.9 dB(A) ranging from 50.7 to 76.6 dB(A). LUR models had a good fit with a R2 of 0.56 for Lden and 0.63 for Lnight in a leave-one-site-out cross validation. Main predictors of noise were the inverse distance to medium roads, count of educational facilities within a 400 m buffer, mean Normalized Difference Vegetation Index (NDVI) within a 100 m buffer, residential areas within a 50 m (Lden) or 25 m (Lnight) buffer and slum areas within a 400 m buffer. Our study suggests that LUR modelling with geographic predictor data is a promising and efficient approach for noise exposure assessment in low- and middle-income countries, where noise maps are not available.

Donor-specific anti-HLA antibodies detected by Luminex: predictive for short-term but not long-term survival after heart transplantation.

In heart transplantation, the clinical significance of pretransplant donor-specific antibodies (DSA) detected by solid phase assay (SPA), which is more sensitive than the conventional complement-dependent cytotoxicity (CDC) assays, is unclear. The aim was to evaluate SPA performed on pretransplant sera for survival after heart transplantation. Pretransplant sera of 272 heart transplant recipients were screened for anti-HLA antibodies using CDC and SPA. For determination of pretransplant DSA, a single-antigen bead assay was performed. The presence of anti-HLA antibodies was correlated with survival. Secondary outcome parameters were acute cellular rejection, graft coronary vasculopathy and ejection fraction. In Kaplan-Meier analysis, SPA-screening did not predict survival (P = 0.494), this in contrast to CDC screening (P = 0.002). However, the presence of pretransplant DSA against HLA class I was associated with decreased short-term survival compared to non-DSA (P = 0.038). ROC curve analysis showed a sensitivity of 76% and specificity of 73% at a cutoff of 2000 MFI. In contrast, the presence of anti-HLA antibodies had no influence on long-term survival, rejection incidence, and graft function. Thus, detection of DSA class I in pretransplant serum is a strong predictor of short-term, but not long-term survival and may help in the early management of heart transplant patients.