Phage typing and PFGE pattern analysis as tools for epidemiological surveillance of Salmonella enterica serovar Bovismorbificans infections

Abstract

Some years ago, an increase in the number of sporadic cases and outbreaks of salmonellosis due to S. enterica serovar Bovismorbificans was observed in several European countries including Finland, Sweden, England/Wales, Austria, and Germany. In order to understand the recent spread of this serovar and to trace the route of infection back to its source, it was considered necessary to subtype S. Bovismorbificans isolates. Using phage typing (newly described here) and molecular fingerprinting (PFGE-pattern, plasmid profiles and ribotype) the isolates of European origin could be subtyped and compared to S. Bovismorbificans isolates that originated in overseas countries such as Australia, Thailand, India, etc. where this serovar was isolated more frequently. Significant clonal diversity was identified but some of the clonal types of S. Bovismorbificans dominated the epidemics and single cases in Europe as well as in overseas countries. The clonal identity among these isolates indicates an international distribution, new sources of infection, and highlights the urgent requirement for standardized laboratory based surveillance networks (e.g. Enter-Net). Moreover, it is suggested that strains of S. Bovismorbificans will continue to be of concern in public health and that phage typing together with PFGE typing can be applied as reliable and rapid tools for their future monitoring.

Investigation Into Individual Health and Exposure to Infectious Agents of Platypuses (Ornithorhynchus Anatinus) in Two River Catchments in Northwest Tasmania

“…However, given the reported associations with wildlife species and water, it is not a surprising finding. Salmonella Bovismorbificans, the other serovar isolated in this project, is relatively common in Australia in animals (particularly cattle) and humans (Liesegang et al 2002;Stafford et al 2002;Animal Health Australia 2012Iveson et al 2013). Outbreaks of human gastrointestinal disease due to Salmonella Bovismorbificans have been associated with raw vegetables in Europe and Australia (Liesegang et al 2002;Stafford et al 2002), and this has led to speculation that the bacteria could survive in soil and watery habitats, leading to infection via vegetables.…”

Cats as a Risk for Transmission of Antimicrobial Drug-Resistant Salmonella

“…The isolated serotypes indicate that the cats were infected from the same sources compared with other animals and man. Indeed, serotypes Typhimurium and Enteritidis are the most widespread serotypes and the serotype Bovismorbificans is not uncommon in other animals, including humans (2,20).…”

Diversity of Phage Types among Archived Cultures of the Demerec Collection of Salmonella enterica serovar Typhimurium Strains

“…Phage typing is frequently used to track Salmonella epidemics across the globe (8,15). Additionally, it is used to identify DT36 ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ DT1 ϩ ϩ ϩ ϩ ϩ ϩ ϩ Ϫ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ Ϫ ϩ ϩ ϩ ϩ DT126 ϩ ϩ ϩ ϩ ϩ Ϫ ϩ Ϫ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ Ϫ ϩ ϩ ϩ ϩ RDNC (3) Ϫ ϩ ϩ ϩ ϩ Ϫ ϩ Ϫ ϩ ϩ ϩ ϩ ϩ ϩ ϩ Ϫ Ϫ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ Ϫ ϩ ϩ ϩ ϩ…”

“…The present battery of 209 definitive phage types (DTs) (L. Ward, personal communication) at the Robert Koch Institute has been used for long-term surveillance of serovar Typhimurium (15) and identification of the spread of different, yet closely related, serotypes in the tracking of disease (8), in addition to tracking host-adapted variants within a particular serovar of S. enterica (13). Because the phage type of a given strain has been shown to be stable under standard laboratory conditions, it can be assumed that these strains all had the same phage type when they were introduced into the vials decades ago.…”

“…In diagnostic laboratories, the sources of epidemics have been traced horizontally across continents and vertically from contaminated food and feed to human and animal disease (8,15,22,23). In light of this observed stability, the difference in phage types between these archived samples is particularly striking.…”