Subject: Penicillin in CSTSS: PLEASE CROSS-POST THE CASE FOR PENICILLIN PROPHYLAXIS OF CANINE STREPTOCOCCAL TOXIC SHOCK SYNDROME

There is no question that if this were a human disease penicillin prophylaxis would be near universal.  Imagine sending a healthy child to school in the morning, being called because of collapse and high fever around noon, and having the child die on the way to the emergency room or shortly after arrival.

As this is being written there are local news anchors making pleas to locate individuals exposed to a person with a case of bacterial meningitis so that prophylactic antibiotics can be given.  Bacterial meningitis is about as infectious as virulent streptococci in humans, and has a much slower onset than either human or canine streptococcal toxic shock syndrome.

THESE DEATHS ARE PREVENTABLE We know the bacterial pathogen responsible for CSTSS, we have a great deal of experience in the treatment and prevention of disease in humans infected with this genus of bacteria, and we have an effective antibiotic treatment with infrequent side effects: Penicillin.

Penicillin has been in widespread use for over 50 years, and continues to be used frequently to prevent streptococcal infections in humans at risk from complications of streptococcal disease, such as rheumatic heart disease, glomerulonephritis, etc., as well as to treat streptococcal skin infections, including cellulitis and impetigo.  It's used before minor dental procedures in individuals at risk.  It targets Gram-positive bacteria specifically, so that there are no intestinal side effects.  Despite widespread use for 50+ years, streptococci continue to be susceptible to this antibiotic, although many other bacteria became resistant years ago.  When used against streptococci, using Penicillin is equivalent to using a rifle rather than a shotgun.

Although we don't know the exact incubation period of CSTSS, it seems to be in the range of 10 to14 days after exposure.  This allows adequate time to give oral penicillin to prevent the development of clinical disease.  The only problem with the use of penicillin is that the primary pharmaceutical manufacturer of penicillin is attempting to cut back on production of parenteral Penicillin G, which has led to a severe shortage of the IV drug.  So far, I believe stocks of oral Pen V-K are adequate.  Ampicillin has been recommended as an alternative to penicillin, but is much less desirable as it affects Gram negative as well as Gram positive bacteria, which can lead to the development of diarrhea if given orally.  Dicloxacillin is a reasonable alternative: it's a penicillinase-resistant penicillin, targets Gram positive bacteria, and is now relatively inexpensive in the oral form.

Penicillin is even relatively inexpensive, probably accounting for the pharmaceutical manufacturer's reluctance to continue to manufacture it.
They of course prefer to promote more expensive alternatives.

If significant exposure factors are involved, such as development of CSTSS in a dog to which my dogs have been closely exposed, or if my dogs' bites have been manually examined after examination of dogs which have developed CTSS, my dogs will have prophylactic treatment, probably with oral Pen V-K.  In my opinion the consequences of failing to prevent this infection are too severe to tolerate.  A mortality rate of 50% or more in those dogs who survive to reach a veterinarian is simply not acceptable.

Lyda Long, M.D.
Ndnmd@ionet.net