Murray Hazlett, Đurđa Slavić, Lisa Sharko 
 
Animal Health Laboratory, University of Guelph, Guelph, ON (Hazlett, Slavić), Oxford Bovine VPC, Beachville, ON (Sharko) 

AHL Newsletter 2020;24(2):7. 

An investigation of a dairy goat herd with issues of pregnancy toxemia, ketosis, hypoglycemia and hypocalcemia resulted in submission of two poor doing 2-year-old does for autopsy at the AHL. 

One of the does had a very large polycystic abdominal mass, about 10 litres in volume which was believed to account for the poor performance. The second doe had severe neutrophilic abomasitis with marked edema, emphysematous enteritis and neutrophilic ulcerative typhlocolitis. A large number of Clostridium ramosum was isolated from the abomasum with a moderate number of Escherichia coli. A small number of Clostridium perfringens was isolated from the cecum. 

Figure 1. A. Marked edema of the abomasal submucosa (lower arrow) and an area of necrosis and ulceration in the mucosa (upper arrow) (H&E stain). B. Clusters of bacterial bacilli within the abomasal mucosa (arrow) (H&E stain). C. Gram-positive Clostridium ramosum organisms at the interface of dead and living tissue. (Gram stain). 
 

Since 2007, 46 isolates of C. ramosum have been reported at the AHL, most being regarded as secondary or opportunistic infections isolated with other bacteria and in various species (10 cattle submissions, 5 caprine, 2 ovine and 7 equine). Most cases of caprine abomasitis diagnosed at the AHL are mild and of unknown cause; many are assumed to be post-parasitic lesions. Parasitic abomasitis is the most commonly-diagnosed cause, followed by Sarcinia and unknown bacterial species. Abomasum is not typically submitted for culture in a majority of cases.  

Clostridium ramosum is a common enteric bacterial species in humans and is a spore-forming anaerobe.  Within the Clostridium genus is a subgroup known as the RIC group, named for the initial letters of its constituents’ species (C. ramosum, C. innocuum, and C. clostridioforme).  Identification can be difficult because of Gram stain variability, spores that are often difficult to see, and atypical colony morphology.1 It is considered to be rarely pathogenic but has been identified in some opportunistic infections in humans including abscesses, otitis and septicemia.2 C. ramosum has been demonstrated to be obesogenic in mice and possibly in humans.   AHL 

References 

1. Alexander CJ et al. Identification and antimicrobial resistance patterns of clinical isolates of Clostridium clostridioforme,  
    Clostridium innocuum, and Clostridium ramosum compared with those of clinical isolates of Clostridium perfringens.  

   J Clin Microbiol 1995;33(12):3209–15. 
2. Forrester JD, Spain DA. Clostridium ramosum bacteremia: Case report and literature review. Surg Infect 2014;15(3):343-346.