Since it seems like “bite wounds” are memorable for certain
bacteria, I have found an article posted this month that works through a case
study of such an infection. This will be a two part post, and I will provide
the answer and link in the second post.
The case begins with a 9.5 year old boy who received a bite
wound to the face from his neighbor’s dog. The dog’s background, including
vaccinations, appeared clear, and it was determined that the instance was “provoked”
from the child. The boy was taken to a nearby hospital where they sutured his
wound and wrote a prescription for antibiotics (amoxicillin/clavulanate) –
clavulanate is asked about in the BOC.
The prescription was not filled, and the boy returned to the
hospital within 24 hours with a fever of 103°F
and painful inflammation. Previous sutures were removed; along with IV
clindamycin (broad spectrum antibiotic) administered. The child began to take
the previous prescription as instructed.
Shortly after, the child returned to the emergency
department for symptoms worsening, and began treatment with ceftriazone IM with
admission into the hospital. His physical exam revealed clear vital signs, but
yellowish discharge from the wounds.
From the information provided, what would you guess the
pathogen is?
Staphylococcus aureus
Eikenelle corrodens
Group A Streptococcus
Pasteurella multocida
Feel free to comment with your guess!
First of all, I would like to know why the mother didn’t take all necessary precautions to ensure the safety of her child by giving the child the prescribed antibiotics in the first place. In regards to the type of bacteria causing the infection, the first one that comes to mind when hearing it is a dog bite wound is Pasteurella species. Eikenella is associated with human bite wounds from mouth flora, so I would not automatically think it would be that one. According to a study by Fredrick M. Abrahamian in the Clinical Microbiology Reviews journal, it represents less than 2% of animal bite wound infections. Staphylococcus aureus could be a possibility from contamination of the boy’s skin flora into the wound. This journal states that Streptococcus and Staphlycoccus represent the second most commonly recovered bacteria from animal bite wounds. Yet, both of these bacteria are found most commonly in non-purulent wounds. The study goes on to say that Pasteurella canis is the number one infecting bacteria from dog bites with Pasteurella multocida being the second most prevalent species.
ReplyDeleteThe infection in this study had a very short incubation (around 24 hours). Also according to the same study, Pasterella spp. has a shorter latency period than Staph and Strep species. I found one other study by Ross A. Pennie in the Canadian Family Physician journal that reports Pasteurella multocida was the most commonly isolated culture from animal bites in the outpatient setting they chose to study. Although only four of the wounds studied were cultured, 2 were P. multocida, 1 was skin flora and 1 grew no pathogen. It reports that amoxicillin/clavulanate is good to excellent at treating mild cases of these infections. However, moderate to severe infections were best treated with a third generation cephalosporins such as ceftriaxone. With all of this said, I would chose Pasteurella multocida as the pathogen.
Very well stated Lindsey. I do agree with all that you have written concerning the information of the typical nature of these organisms. I do want to answer your first question, or at least offer my opinion on it. The article never states the reason for why the boy did not receive the oral antibiotics as planned, how often he would be required to take it, and specific times were not given on his actual visit and return visit. I would assume that the initial accident happened in the evening, maybe after coming home from school. It may have been to late after their visit to fill the prescription at a nearby pharmacy, or perhaps they planned to do so the next morning on the way to work, etc. Of course the next day he was actually worse, and they returned to the clinic. I do not think the lack of his antibiotic was out of "negligence", but maybe just the timing of the accident and return visit being too close together for a dose to be required. Now, this is just speculation. The article is quite lengthy, but I received the impression that the parents really were concerned and trying their best. Thank you for your top notch comment!!!
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