Wednesday, April 1, 2015

Human Gets Staph Infection from Dog Saliva

Dr. Stephen Page, regular supplier of good material, sent me a couple papers from the Quarterly Journal of Medicinethe other day. One’s an interesting report of ‘Staphylococcus intermedius’ infection in a person, in a case report entitled'A canine bug in a human heart' (Koci et al, Q J Med 2015;108:337-338).
It’s almost guaranteed that this wasn’t S. intermedius but rather S. pseudintermedius (some medical microbiology labs are apparently still a couple decades behind in identifying this bug). Regardless, it’s an interesting case of a 58-yr-old man with a pacemaker that developed fever, chills and a headache. He reported that a neighbour’s dog had licked his hand a few weeks earlier. The pacemaker incision site was unremarkable but ‘Staphylococcus intermedius’ was isolated from two different blood samples. That's a concern because of the potential for infection of the heart valves and/or the pacemaker leads. Infections like that can be serious and hard to eliminate (especially since we know that S. pseudintermedius tends to produce biofilm, which helps it hang around sites like pacemaker leads and avoid antibiotics. Fortunately, after a couple rounds of antibiotics and removal of the pacemaker system, he recovered uneventfully
It’s interesting (and encouraging) that the dog exposure was reported. Whether he offered the info or they asked isn’t clear, but this is the type of information that’s often missed.
Putting this report into perspective is important. This, and various other reports of S. pseudintermedius infections, show that this dog-associated bacterium can cause disease in people.
  •  Single cases continue to appear in the medical literature. That means it’s really rare (since a single occurrence is enough to prompt a publication).
  • The relative risk from exposure is limited. Most dogs carry this bacterium and huge numbers of people are exposed every day. So, the incidence of disease with respect to exposure is incredibly low
While ‘low’ is good, it’s not much consolation if you’re the one with the rare but life-threatening infection. So, some basic (common sense) practices are indicated. Avoiding contact of dog saliva with open wounds would be one. Good general hygiene practices (especially handwashing), avoiding contact with feces and similar basic measures are probably the key….along with making sure physicians know about animal contact and think about potential zoonotic infections. That’s particularly true for people that are at increased risk of disease.

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