A case of wound dual infection with Pasteurella dagmatis and Pasteurella Canis resulting from a dog bite - limitations of Vitek-2 system in exact identification of Pasteurella species

Abstract

BackgroundPasteurella species, widely known as indigenous orgganisms in the oral and gastrointestinal floras of many wild and domestic animals, are important pathogens in both animals and humans. Human infections due to Pasteurella species are in most cases associated with infected injuries following animal bites. We encountered a rare case of dual infections caused by different two Pasteurella species occurred in a previously healthy 25-year-old female sustaining injury by a dog-bite.MethodologyExudates from the open wound of her dog-bite site, together with the saliva of the dog were submitted for bacteriological examination. Predominantly appearing grayish-white smooth colonies with almost the same colonial properties but slightly different glistening grown on chocolate and sheep blood agar plates were characterized morphologically by Gram's stain, biochemically by automated instrument using Vitek 2 system using GN cards together with commercially available kit system, ID-Test HN-20 rapid panels, and genetically by sequencing the 16S rRNA genes of the organism using a Taq DyeDeoxy Terminator Cycle Sequencing and a model 3100 DNA sequencer instrument.ResultsThe causative isolates from the dog-bite site were finally identified as P. canis and P. dagmatis from the findings of the morphological, cultural, and biochemical properties together with the comparative sequences of the 16S rRNA genes. Both the isolates were highly susceptible to many antibiotics and the patient was successfully treated with the administration of so-called the first generation cephalosporin, cefazolin followed by so-called the third generation cephalosporin, cefcapene pivoxil. The isolate from the dog was subsequently identified as P. canis, the same species as the isolate from the patient.ConclusionsTo the best of our knowledge, this was the second report of a dual infection with Pasteurella species consisting of P. dagmatis and P. canis resulting from a dog-bite, followed by the first report of dual infections due to P. dagmatis and P. multocida in 1988. Our isolate finally identified as P. dagmatis was misidentified as P. pneumotripica by means of the Vitek 2 system. The species name "P. dagmatis" was not included in the database of the system. It is also important for routine clinical microbiology laboratories to know the limitation of the automated Vitek 2 system for the accurate identification of Pasteurella species especially P. dagmatis. It should be emphasized that there still exists much room for improvement in Vitek 2 system. Significant improvement of Vitek 2 system especially in the identification of Pasteurella species is urgently desired.

Comparison of the Oral Microbiomes of Canines and Their Owners Using Next-Generation Sequencing

“…Pasteurella spp. infrequently cause systemic infectious diseases and mostly infect patients with underlying diseases [ 20 ]. Capnocytophaga cynodegmi canine oral taxon 254 clone ZX121, the causative agent of bite wound infections [ 21 ], was also identified (485 reads).…”

Septic monoarthritis with isolation ofP dagmatisas a monoculture in the stifle joint of a dog

“…In the second two studies of Griffin and Holt8 and Meyers and others11, the isolates were identified with help of Analytic Profile Index tests (API) by BioMerieux. P dagmatis is not registered in the identification table of API 20 NE, and thus this method is not able to identify the bacterium 3. As this is a standard identification method, this could lead to a misidentification of P dagmatis and subsequently an underestimation of its frequency.…”

Bacteremia Due to Pasteurella dagmatisAcquired from a Dog Bite, with a Review of Systemic Infections and Challenges in Laboratory Identification

“…Bacteria from the Pasteurellaceae family cause zoonotic infections in humans, with P multocida and P canis being the most common Pasturella species reported in human infections ( 7 , 8 ). Infections caused by Pasteurella species are typically introduced by animals, particularly cat or dog bites, but also occasionally by other animals, and often manifest as skin or soft tissue infections ( 7 – 9 ). Sometimes, animal contact is not prominent in the initial patient history ( 10 , 11 ) ( Table 3 ).…”

“…Interestingly, while Pasturella species infrequently cause systemic infectious disease, in our review of the literature, when P dagmatis infections are reported, they appear to be frequently associated with severe disseminated infection including bacteremia. Coinfections of P dagmatis with another Pasturella species have also been observed ( 9 , 12 , 22 ); therefore, it is important for the laboratory to test multiple morphotypes from the plate to ensure that >1 Pasturella species is not present.…”