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Clostridium sordellii, a traditional and emerging pathogen

Bruce Watt, Local Land Services, Bathurst and Patrick Staples, State Veterinary Diagnostic Laboratory, Menangle

Posted Flock & Herd February 2015


Clostridium sordellii is one of the anaerobes responsible for malignant oedema, a wound infection of sheep, cattle and other species that develops in the subcutaneous fascia and causes an acute fatal toxaemia. Clostridium septicum is the most common causal agent but C. chauvoei and C. novyi have both been implicated while C. perfringens type A and C. sordellii are less frequently isolated (Beveridge WIB, 1983).

However, elsewhere, C. sordellii has been isolated from a number of new syndromes; in Europe and the Middle East, sudden death in sheep of all ages, acute abomasitis in calves and young lambs, haemorrhagic enteritis, sudden death and abomasitis in finishing lambs (Lewis and Naylor 1998, Vatn et al. 2000, Akan et al. 2008) fatal peri-parturient disease in ewes (Lewis 2007) and in New Zealand, sudden death in sheep and growing cattle (West et al. 2009, Vermunt et al. 2010).


Approximately 400 2-3 month old mixed sex merino lambs were marked in early October 2014. The lambs were not vaccinated at marking and the ewes had not been vaccinated pre-lambing. Four days later, 15 of the 200 male lambs in the mob died and several more were sick, while none of the 200 females died or were observed to be sick.

Clinical examination

The mob was examined in the paddock. Several male lambs were reluctant to walk. One was found in lateral recumbency, alert but unable (or reluctant) to stand. On examination this lamb had a marked swelling of the subcutaneous tissues of the ventral abdomen with purplish skin discolouration at edges of the swelling. This lamb had a moderately swollen scrotum with the ventral third of the scrotum surgically removed consistent with castration.

Image of moribund sheep with abdominal swelling
Figure 1. Lamb showing marked ventral oedema four days post castration (arrow)
Image of lamb inguinal region
Figure 2. Purple discolouration of tissues in the inguinal region and at the
edge of the oedematous swelling (arrow)

Necropsy findings

A recently castrated 25 -30 kg, 3-4 month old merino was euthanased and necropsied. The most remarkable finding was the extensive clear brownish ventral, subcutaneous oedema extending from the inguinal area to the brisket (figures 1, 3). On incising the scrotum the scrotal sac was found to be lined with thickened, red to purple tissue with brownish oedema fluid visible in the spermatic cord most notable around the testicular lymph node (figure 4).

Image of sheep inguinal region post-mortem
Figure 3. Brownish, subcutaneous oedema in the inguinal region (arrow)
Image of sheep scrotum on post-mortem
Figure 4. Dark red, swollen lining of scrotum on opening at autopsy (lower arrows). Brown oedematous tissue in the tissues surrounding the cord cranial to the scrotum (upper arrows).

Laboratory Findings

Routine culture of the oedematous, subcutaneous fascia grew no bacteria while routine culture of the infected scrotum grew a moderate mixed growth including Trueperella pyogenes. Anaerobic cultures of both the fascia and the scrotum grew a profuse growth (pure and predominant respectively) of Clostridium spp. A smear of the pure culture grown from subcutaneous tissue was submitted for clostridial fluorescent antibody testing. The sample was negative for C. chauvoei, C. novyi type B and C. septicum but was positive for C. sordellii.


Approximately 50 lambs were treated intramuscularly with 5 ml of penicillin (procaine penicillin 150mg/mL, benzathine penicillin 150mg/mL and procaine hydrochloride 20mg/ml, Benacillin, Ilium). The mob was also vaccinated with 5-in-1 clostridial vaccine. While this treatment curtailed losses, it is of interest that C. sordellii antigens are not included in standard 5 in 1 vaccines, so the vaccine was presumably not protective.


Traditionally, C. sordellii is one of the anaerobes associated with malignant oedema in cattle and sheep. However, in Europe, Turkey and New Zealand, it has emerged as a cause of a range of new or newly described diseases, most notably abomasitis and sudden death in sheep and cattle. In a pattern reminiscent of enterotoxaemia, deaths are most often seen in rapidly growing animals often associated with a change of diet and high dietary carbohydrate. Like braxy (caused by Cl. septicum), abomasitis may be seen in sheep grazing root crops and new pastures, suggesting that soil borne spores may contribute (Lewis 2007).

In cases of abomasitis, the abomasal mucosa is congested, eroded and sometimes ulcerated while the abomasal wall is oedematous and emphysematous. Erosions and congestion are present in the abomasal mucosa. While cases in older sheep are less defined, there may be peritonitis and abomasal ulceration.

In cases of sudden death, there is evidence of toxaemia and rapid autolysis. In New Zealand, young, rapidly growing cattle on highly digestible pastures are most susceptible (Vermunt et al. 2010).

Unlike some other species of Clostridia, C. sordellii is not a normal component of gut flora, but it is widespread in the environment and can invade wounds and tissues pre- and post-mortem. Because of the possibility of post-mortem invasion, its isolation alone is not sufficient evidence to confirm causation. Vermunt et al. (2010) therefore cautioned that, before a diagnosis of C. sordellii sudden death is made, frothy bloat should be excluded and that C. sordellii should be isolated from liver and muscle sampled shortly after death. In this case C. sordellii was isolated in pure growth from subcutaneous tissue obtained immediately after euthanasia, confirming its role in the outbreak (bearing in mind that only one lamb was necropsied).

In New Zealand and the United Kingdom, but not in Australia, vaccines containing C. sordellii antigens are available to prevent this disease (West et al. 2009, Lewis 2007). Given that C. sordellii is not commonly diagnosed in Australia this seems reasonable, but it is also possible that the other disease manifestations occasionally occur here without diagnosis.


  1. Akan M, Sareyyupoglu B, Oncel C, Tel OY, Ilhan Z and Cantekin Z (2008) Isolation of Clostridium sordellii from abomasum lesions of lambs in Turkey Ankara √úniversitesi Veteriner Fak√ľltesi Dergisi 55:103-106
  2. Beveridge WIB (1983) Animal Health in Australia: Bacterial Diseases of Sheep and Cattle 4:73-75
  3. Lewis CJ and Naylor RD (1998) Sudden death in sheep associated with Clostridium sordellii. The Veterinary Record 142(16):417-421
  4. Lewis CJ (2007) Clostridial diseases, chapter 23 in Diseases of Sheep, Fourth Edition edited by Aitken ID, p 162
  5. Vatn S, Tranulis MA and Hofshagen M (2000) Sarcina-like bacteria, Clostridium fallax and Clostridium sordellii in Lambs with Abomasal Bloat, Haemorrhage and Ulcers Journal of Comparative Pathology 122(2-3):193-200
  6. Vermunt JJ, Malmo J and Parkinson TJ (2010) Causes of Sudden Death, chapter 23 in Parkinson TJ, Vermunt JJ and Malmo J Diseases of Cattle in Australasia. A comprehensive textbook. New Zealand Veterinary Association Foundation for Continuing Education, Wellington, p 792
  7. West DM, Bruere AN and Ridler AL (2009) The Sheep: Health, Disease and Production, 3rd Edition, p 319


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