Organic Turkey Flocks: A Reservoir of Streptococcus gallolyticus subspecies gallolyticus

Abstract

Streptococcus gallolyticus subspecies gallolyticus (S. gallolyticus) can colonise the gastrointestinal tract of humans and animals and is known to cause similar infections in both humans and animals. Data about the spread or prevalence in farm animals are missing. In this study, Trypton Soya Agar was modified to a selective medium enabling the isolation and quantification of S. gallolyticus from faecal samples. The bacterium was observed in 82 out of 91 faecal samples obtained from 18 different organic turkey flocks. The prevalence of shedding birds was estimated by the number of positive fresh droppings and reached up to 100% on most farms. Furthermore, for the first time S. gallolyticus was quantified in faeces from poultry flocks. The median of colony forming units (CFU) per gramme faeces was 3.6 x 105CFU/g. Typing of one isolate from each positive faecal sample by multilocus sequence typing delivered 24 sequence types (STs). Most of the isolates belonged to the clonal complex CC58. The same STs of this complex were detected in up to six different flocks. Partly, these flocks were located in various regions and stocked with varying breeding lines. Regarding the biochemical profiles of the same STs from different farms, the results did not contradict a spread of specific STs in the organic turkey production. Moreover, checking the pubMLST database revealed that STs found in this study were also found in other animal species and in humans. The high detection rate and the number of S. gallolyticus in turkey faeces indicate that this bacterium probably belongs to the common microbiota of the gastrointestinal tract of turkeys from organic flocks. Furthermore, the findings of this study support the suggestion of a possible interspecies transmission.

The Road to Infection: Host-Microbe Interactions Defining the Pathogenicity of Streptococcus bovis/Streptococcus equinus Complex Members

“…SBSEC members have been isolated from the GIT or blood system of birds, companion animals, livestock (ruminants, poultry and pigs), marsupials, aquatic mammals and game (Jans et al, 2015 ), but prevalence data is limited to birds, cattle and lamb. SGG was found in over 90% of fecal droppings in turkey flocks and reached up to 80% prevalence in pigeon crop and cloaca samples (De Herdt et al, 1994a , b ; Schulz et al, 2015 ). SBSEC members were also isolated from chicken crops, but less frequently and not as predominant bacteria (Baele et al, 2001 ).…”

“…Furthermore, soil clay adhesion of SB from bovine feces is very strong and cannot be desorbed after 24 h whereas long-term persistence seems weak but possibly sufficient to establish transmission within shorter time frames as observed among poultry flocks, surrounding environment and workers. In laying hens, colonization of non-carrier birds introduced into an SGG -positive flock took approximately 35 weeks and occurred likely via feed and feces (Guy et al, 1980 ; Dumke et al, 2015 ; Schulz et al, 2015 ). SGG isolates of identical sequence types where thereby causing infection in one worker and contributing to in-flock and old-young transmission in hens (Dumke et al, 2015 ).…”

“…SGG isolates of identical sequence types where thereby causing infection in one worker and contributing to in-flock and old-young transmission in hens (Dumke et al, 2015 ). Similarly, sequence types were shared between turkey, pigeons, chicken and humans (Schulz et al, 2015 ). Rural residency, close animal-human contact and the use of manure as fertilizer were identified as risk factors for colonization with SGG, SGP, SII, SL , and SB in humans (Giannitsioti et al, 2007 ; Corredoira et al, 2008 ; Dumke et al, 2017 ).…”

Potential Transmission Pathways of Streptococcus gallolyticus subsp. gallolyticus

“… * +: positive cultivation on selective medium;-: negative cultivation on selective medium [ 25 ]; (#) : cultivation of the blood culture; see material and method section ** sequence type p.f. pooled fecal samples, p.d.…”

“…gallolyticus subsp. gallolyticus , as described previously [ 25 ]. Furthermore, two pooled dust samples were randomly taken from different locations in the laying hen flock (maximum distance to laying hens: 1 meter), as described previously [ 26 ].…”