Background In December, 2019, the newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, causing COVID-19, a respiratory disease presenting with fever, cough, and often pneumonia. WHO has set the strategic objective to interrupt spread of SARS-CoV-2 worldwide. An outbreak in Bavaria, Germany, starting at the end of January, 2020, provided the opportunity to study transmission events, incubation period, and secondary attack rates.Methods A case was defined as a person with SARS-CoV-2 infection confirmed by RT-PCR. Case interviews were done to describe timing of onset and nature of symptoms and to identify and classify contacts as high risk (had cumulative face-to-face contact with a confirmed case for ≥15 min, direct contact with secretions or body fluids of a patient with confirmed COVID-19, or, in the case of health-care workers, had worked within 2 m of a patient with confirmed COVID-19 without personal protective equipment) or low risk (all other contacts). High-risk contacts were ordered to stay at home in quarantine for 14 days and were actively followed up and monitored for symptoms, and low-risk contacts were tested upon self-reporting of symptoms. We defined fever and cough as specific symptoms, and defined a prodromal phase as the presence of non-specific symptoms for at least 1 day before the onset of specific symptoms. Whole genome sequencing was used to confirm epidemiological links and clarify transmission events where contact histories were ambiguous; integration with epidemiological data enabled precise reconstruction of exposure events and incubation periods. Secondary attack rates were calculated as the number of cases divided by the number of contacts, using Fisher's exact test for the 95% CIs.Findings Patient 0 was a Chinese resident who visited Germany for professional reasons. 16 subsequent cases, often with mild and non-specific symptoms, emerged in four transmission generations. Signature mutations in the viral genome occurred upon foundation of generation 2, as well as in one case pertaining to generation 4. The median incubation period was 4•0 days (IQR 2•3-4•3) and the median serial interval was 4•0 days (3•0-5•0). Transmission events were likely to have occurred presymptomatically for one case (possibly five more), at the day of symptom onset for four cases (possibly five more), and the remainder after the day of symptom onset or unknown. One or two cases resulted from contact with a case during the prodromal phase. Secondary attack rates were 75•0% (95% CI 19•0-99•0; three of four people) among members of a household cluster in common isolation, 10•0% (1•2-32•0; two of 20) among household contacts only together until isolation of the patient, and 5•1% (2•6-8•9; 11 of 217) among non-household, high-risk contacts.Interpretation Although patients in our study presented with predominately mild, non-specific symptoms, infectiousness before or on the day of symptom onset was substantial. Additionally, the incubation period was often very short ...

The need for timely establishment of diagnostic assays arose when Germany was confronted with the first travel-associated outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Europe. We describe our laboratory experiences during a large contact tracing investigation, comparing previously published real-time RT-PCR assays in different PCR systems and a commercial kit. We found that assay performance using the same primers and probes with different PCR systems varied and the commercial kit performed well.At the end of December 2019, an outbreak caused by a novel coronavirus was announced in Wuhan, China. Since then, the number of cases has increased, especially in China but also in other countries, and public health authorities are in need to rapidly implement diagnostic tools. In this paper, we describe our laboratory experiences with the novel real-time RT-PCR assays comparing different one-step PCR systems and a commercial kit, using a Bio-Rad CFX 96 cycler.

The genus Borrelia, originally described by Swellengrebel in 1907, contains tick- or louse-transmitted spirochetes belonging to the relapsing fever (RF) group of spirochetes, the Lyme borreliosis (LB) group of spirochetes and spirochetes that form intermittent clades. In 2014 it was proposed that the genus Borrelia should be separated into two genera; Borrelia Swellengrebel 1907 emend. Adeolu and Gupta 2014 containing RF spirochetes and Borreliella Adeolu and Gupta 2014 containing LB group of spirochetes. In this study we conducted an analysis based on a method that is suitable for bacterial genus demarcation, the percentage of conserved proteins (POCP). We included RF group species, LB group species and two species belonging to intermittent clades, Borrelia turcica Güner et al. 2004 and Candidatus Borrelia tachyglossi Loh et al. 2017. These analyses convincingly showed that all groups of spirochetes belong into one genus and we propose to emend, and re-unite all groups in, the genus Borrelia.

From 2016 through the middle of 2017, the German Consiliary Laboratory on Diphtheria noted an increase in nontoxigenic Corynebacterium diphtheriae isolates submitted from cities in northern Germany. Many patients for whom epidemiologic data were available were homeless, alcohol or drug abusers, or both. After performing routine diagnostics and multilocus sequence typing (MLST), we analyzed isolates of sequence type (ST) 8 and previously submitted isolates by whole-genome sequencing. Results were analyzed for phylogenetic relationship by core genome MLST (cg-MLST) and whole-genome single-nucleotide polymorphism profiles. Next-generation sequencing–based cg-MLST revealed several outbreak clusters caused by ST8; the geographic focus was in the metropolitan areas of Hamburg and Berlin. To achieve enhanced analytical depth, we used additional cg-MLST target genes and genome-wide single-nucleotide polymorphisms. We identified patient characteristics and detected transmission events, providing evidence that nontoxigenic C. diphtheriae infection is a potential public health threat in industrialized countries.

A total of 34 Corynebacterium sp. strains were isolated from caseous lymph node abscesses of wild boar and roe deer in different regions of Germany. They showed slow growth on Columbia sheep blood agar and sparse growth on Hoyle’s tellurite agar. Cellular fatty acid analysis allocated them in the C. diphtheriae group of genus Corynebacterium . MALDI-TOF MS using specific database extensions and rpoB sequencing resulted in classification as C. ulcerans . Their quinone system is similar to C. ulcerans , with major menaquinone MK-8(H2). Their complex polar lipid profile includes major lipids phosphatidylinositol, phosphatidylinositol-mannoside, diphosphatidylglycerol, but also unidentified glycolipids, distinguishing them clearly from C. ulcerans . They ferment glucose, ribose and maltose (like C. ulcerans ), but do not utilise d-xylose, mannitol, lactose, sucrose and glycogen (like C. pseudotuberculosis ). They showed activity of catalase, urease and phospholipase D, but variable results for alkaline phosphatase and alpha-glucosidase. All were non-toxigenic, tox gene bearing and susceptible to clindamycin, penicillin and erythromycin. In 16SrRNA gene and RpoB protein phylogenies the strains formed distinct brancheswith C. ulcerans as nearest relative.Whole genome sequencing revealed the unique sequence type 578, a distinctbranch in pangenomic core genome MLST, average nucleotide identities <91%, enhancedgenome sizes (2.55 Mbp) and G/C content (54.4 mol%) compared to related species.These results suggest that the strains represent a novel species, for which wepropose the name Corynebactriumsilvaticum sp. nov., based on their first isolation from forest-dwellinggame animals. The type strain isKL0182T (= CVUAS 4292T = DSM 109166T = LMG 31313T= CIP 111 672T).