Streptococcal infection

From Felipedia

Abdomen of Sphinx kitten that died from Strep G infection at 6 days old. Note the dark discolouration around the umbilical area

A 6-week-old Persian which died from respiratory hemorrhage secondary to β-haemolytic streptococcal infection. Courtesy Dr Jim Euclid

β-haemolytic streptococci (esp, Streptococcus canis), are part of the normal flora of the feline skin and genital tract, but can cause significant morbidity and mortality in kittens, usually in the first few weeks of life.

Causes

These bacteria are a common pathogen in catteries and shelters^[1]. Many factors can predispose kittens to neonatal septicaemia: failure of passive transfer of antibodies (inadequate colostrum intake, or inadequate antibody levels in the queen), high levels of pathogenic bacteria in the birth canal or from the queen (saliva, milk), unhygienic environment, failure of passive local immunity (inadequate nursing, or inadequate immunoglobulin levels in milk). Pathogenic bacteria may enter the kitten via the mouth, intestinal tract, genital or urinary tract, or umbilical cord. The most important routes of infection are the mouth and the umbilical cord. Kittens may show signs of difficulty breathing associated with blood loss (usually chest cavity) and secondary pneumonia, but sudden deaths are also common.

S. canis is found in the vaginas of about 50% of young queens. The carriage rate in queens up to 2 years may be 100% in some catteries. Generally, the queens themselves are healthy. The highest incidence of infection is in kittens from the first litter born to a young queen (under 2 years). Older queens are more likely to have eliminated the bacteria spontaneously. Toms can also carry the bacteria in their prepuce, leading to rapid spread of the bacteria in a naive cattery.

Omphalophlebitis (umbilical infection) results when pathogenic bacteria from the queen's saliva or the environment invade the umbilical cord. Normally, the queen chews off the umbilical cord a few inches from the body wall. The cord quickly dries which limits bacterial invasion of both the cord and the umbilicus. If the cord is severed too short, especially if it is severed flush with the abdomen, bacterial invasion may occur or an umbilical hernia may result. An abscess may form at the umbilicus, either just under the skin, or inside the abdomen. Bacteria may also enter the bloodstream via the umbilical vein (which stays partly open for several days) and cause septicaemia. The two most common agents of omphalophlebitis are haemolytic E. coli and Streptococcus canis. If the cause of the infection is not immediately known, antibiotics with coverage of both gram-negative and gram-positive organisms should be chosen (e.g. enrofloxacin and cephalexin once daily if under 2 weeks of age).

Clinical signs

Streptococcus canis was first identified as a cause of neonatal mortality in the mid-1980s. Most affected kittens die between 5 and 10 days. They may have no clinical symptoms of illness until hours before death, although they often gain weight slower than their uninfected littermates.

A transient fever may be present in the 24 hours prior to death. Kittens are infected with the bacteria from the queen's vagina during birth. Usually not all of the kittens in the litter are affected. An abscess of the umbilicus spreads into the liver and abdominal cavity, leading to peritonitis and septicaemia. Some kittens may have an obvious umbilical abscess or swelling. The diagnosis is confirmed by culture of the umbilicus, liver, peritoneal cavity or lungs at necropsy.

A second syndrome associated with S. canis is also seen where kittens develop abscessation of lymph nodes in the neck at about 3-6 months of age^[2].

Treatment

Antibiotic therapy is rarely effective in eliminating S. canis from a queen's vagina. However, a single dose of combined procaine and benzathine penicillin given to the queen at parturition may temporarily suppress the S. canis population and decrease risk of infection in the kittens^[3].

Kitten mortality from S. canis is the highest when the bacteria first enters a cattery. Thereafter, any naive queens entering the cattery may become infected and have a high mortality rate in their first litters. Most affected kittens die too quickly for effective treatment. Since S. canis is almost uniformly sensitive to penicillin, remaining littermates can be treated prophylactically with oral amoxicillin paediatric suspension (every 12 hours for 5 days).

The risk of kitten mortality from S. canis can be managed prophylactically in catteries. The umbilical cord should be dipped in 2% tincture of iodine promptly after birth. In catteries experiencing recent kitten deaths from S. canis, kittens can be given a single SC injection of 0.25 ml of a 1:6 dilution in sterile 0.9% saline of product containing 150,000 IU/ml benzathine and procaine penicillin G.

Queens are best treated with prophylactic doses of amoxicillin/clavulanate and/or azithromycin for 2-3 weeks prepartum^[4].

Reference

1. ↑ Pesavento, PA et al (2007) Fatal Streptococcus canis infections in intensively house shelter cats. Vet Pathol 444:218
2. ↑ Greene, CR & Prescott, JF (2006) Streptococcal and other Gram-positive bacterial infections. In Greene, CE (Ed): Infectious diseases of the dog and cat. Saunders, St Louis. pp:302
3. ↑ Blanchard P, Wilson D. Group G streptococcal infections in kittens (1989) In Kirk RW, Bonagura JD (editors): Current Veterinary Therapy X: Small Animal Practice, W.B. Saunders, Philadelphia, 1989, pp. 1091-1093
4. ↑ Ruch-Gallie, RA et al (2008) Efficacy of amoxicillin ans azithromycin for the empirical treatment of shelter cats with suspected bacterial upper respirtatory infections. JFMS 10:542