A few months ago, I wrote about an article that appeared in the journal Orthopedics. It was a very bad article that blamed a person’s infection on "excessive contact" with pets, with no evidence that the pets were involved (and no evidence that dogs have ever been found to carry the bacterium in question).

Here’s the Letter to the Editor that was just published.

Dear Editor:

I was surprised to see the article “Pyogenic cervical spondylitis caused by Pasteurella haemolytica attributed to excessive contact with dogs” by Machino et al. 1 The authors stated that Pasteurella haemolytica (which was renamed Mannheimia haemolytica over a decade ago) is a common inhabitant of the oral cavities of dogs and cats, citing prevalence rates of 71% to 90% in cats and 21% to 60% in dogs. However, they provided no references for these prevalence data, and I am unaware of any studies that have found this bacterium in the oral cavities of dogs, let alone at such high rates. The authors cited 3 articles as supporting zoonotic infections with this organism, yet these 3 articles all involved other Pasteurella species. Pasteurella multocida, a completely different bacterium, is a common oral commensal in dogs and cats and has been reported frequently as a cause of pet-associated infection. The authors may have confused these markedly different organisms. The authors also stated that the recent increase in pet ownership has caused an increase in P haemolytica infections from bite wounds, with no evidence supporting an increase in infections caused by this bacterium or the role of pets in human P haemolytica infections. Although zoonotic infections are problematic and it is important to consider the potential role of household pets in human disease, this article is highly flawed, and retraction should be considered.

J. Scott Weese, DVM, DVSc, DipACVIM
Guelph, Ontario, Canada 

The authors either didn’t get any of the points I made or didn’t care and wrote a rather evasive response.

We thank Dr Weese for his letter. We reported a rare case of Pasteurella haemolytica as the pathogenic bacteria behind pyogenic cervical spondylitis. We searched the literature for reports on spondylitis caused by P haemolytica to the greatest extent possible, but it seems that the present case was the first.

In the present case, a needle aspiration biopsy was performed under diskographic guidance, and P haemolytica was detected on bacterial culture. We believed that this case was caused by P haemolytica. Because the patient owns 2 dogs and frequently kisses them on the mouth, this excessive contact was believed to be the cause of infection. No other causes were evident in this case. Although we cannot declare that it is the cause, no evidence was found that it was not the cause.

Our main point in the article was that osteomyelitis has been reported in the field of orthopedics, and, keeping in mind the fact that pyogenic spondylitis is also caused by rare bacterium, we believe it is important to engage in routine treatment regimens.

Masaaki Machino, MD

Anyway, the point wasn’t to make the authors look bad. It was to remind people that we need to consider pets as sources of infection but do so in a logical manner, and simply blaming the pet when there’s no evidence doesn’t do anyone any good.