Genomic Epidemiology of Campylobacter jejuni Transmission in Israel

Objectives:Campylobacter jejuni is responsible for 80% of Campylobacter infections in Israel, a country with a high incidence reaching 91/100,000 population. We studied the phylogeny, diversity and prevalence of virulence factors using whole genome sequencing (WGS) of a national sample of C. jejuni clinical, food, and animal isolates collected over a 10-year period (2003–2012).Methods:C. jejuni isolates (n = 263) were subject to WGS using Illumina sequencing (PE 250bpx2). Raw reads and de novo assemblies were analyzed with the BioNumerics whole genome MLST (wgMLST) pipeline. Reads were screened for 71 virulence genes by the SRST2 script. Allelic profiles were analyzed to create minimum spanning trees and allelic core distances were investigated to determine a reliable cutoff for strain determination.Results: wgMLST analysis of 263 C. jejuni isolates indicated significant diversity among the prevalent clonal complexes (CCs) with CC-21 and CC-353 being the most diverse, and CC-574 the most clonal. Within CC-21, sequence type (ST)-1359 created a separate clade. Human, poultry and bovine isolates clustered together across the different STs. Forty four percent of studied isolates were assigned to 29 genetic clusters. Temporal and geographical relatedness were found among the minority of clusters, while most phylogenetically associated cases appeared diffuse and unassociated epidemiologically. The majority of virulence factors were highly prevalent across the dataset and not associated with genotype, source of isolation or invasiveness. Conversely, all 13 genes associated with type VI secretion system (T6SS) were lineage-related and identified in only 18% of the isolates. T6SS was detected in 95.2% of ST-1359, a common type in Israel.Conclusions: wgMLST supported the assessment that poultry and cattle are likely food sources of infection in Israel. Substantial genetic clustering among C. jejuni isolates suggested multiple point source and diffuse outbreaks that were previously unreported in Israel. The high prevalence of T6SS among ST-1359 isolates is unique to Israel, and requires further investigation. This study exemplifies the importance of studying foodborne pathogens using advanced genomic approaches across the entire spectrum of One Health

Monkeypox: another test for PCR

Monkeypox was declared a public health emergency of international concern by the World Health Organization (WHO) on 23 July 2022. Between 1 January and 23 July 2022, 16,016 laboratory confirmed cases of monkeypox and five deaths were reported to WHO from 75 countries on all continents. Public health authorities are proactively identifying cases and tracing their contacts to contain its spread. As with COVID-19, PCR is the only method capable of being deployed at sufficient speed to provide timely feedback on any public health interventions. However, at this point, there is little information on how those PCR assays are being standardised between laboratories. A likely reason is that testing is still limited on a global scale and that detection, not quantification, of monkeypox virus DNA is the main clinical requirement. Yet we should not be complacent about PCR performance. As testing requirements increase rapidly and specimens become more diverse, it would be prudent to ensure PCR accuracy from the outset to support harmonisation and ease regulatory conformance. Lessons from COVID-19 should aid implementation with appropriate material, documentary and methodological standards offering dynamic mechanisms to ensure testing that most accurately guides public health decisions

The Human Sense of Smell: Are We Better Than We Think?

Gordon Shepherd challenges the notion - based on genetic evidence - that olfaction is less well developed in humans as compared to other mammal

Community-Acquired Methicillin-Resistant Staphylococcus aureus in Institutionalized Adults with Developmental Disabilities1

Methicillin-resistant Staphylococcus aureus (MRSA) has recently been reported to emerge in the community setting. We describe the investigation and control of a community-acquired outbreak of MRSA skin infections in a closed community of institutionalized adults with developmental disabilities. In a 9-month period in 1997, 20 (71%) of 28 residents had 73 infectious episodes. Of the cultures, 60% and 32% obtained from residents and personnel, respectively, grew S. aureus; 96% and 27% were MRSA. All isolates were genetically related by pulsed-field gel electrophoresis and belonged to a phage type not previously described in the region. No known risk factors for MRSA acquisition were found. However, 58 antibiotic courses had been administered to 16 residents during the preceding 9 months. Infection control measures, antibiotic restriction, and appropriate therapy resulted in successful termination of this outbreak. Selective antibiotic pressure may result in the emergence, persistence, and dissemination of MRSA strains, causing prolonged disease

Long-ranged attraction between disordered heterogeneous surfaces

Long-ranged attractions across water between two surfaces that are randomly covered with (mobile) positive and negative charge domains have been attributed to induced correlation of the charges (positive lining up with negative) as the surfaces approach. Here we show, by directly measuring normal forces under a rapid shear field, that these attractions may not in fact be due to such correlations. It is rather the inherent interaction-asymmetry between equally- and between oppositely-charged domains that results in the long-ranged attraction even in the complete absence of any charge correlation