Bacterial isolates recovered from fresh, untreated animal bite wounds: a prospective single-center case series of 11 patients in the Taihu Lake region

Animal bite wounds carry polymicrobial flora from companion animal oral cavities. Knowledge of the bacterial spectrum in fresh bite wounds informs empirical antibiotic selection. Regional bacteriological data focusing on fresh, unmanaged bite wounds are lacking for the Taihu Lake region of eastern China. This prospective case series enrolled 11 patients presenting with fresh animal bite wounds at a regional emergency center in the Taihu Lake region. Wound swabs were collected at the first emergency visit before any irrigation, disinfection or systemic antibiotic administration. Six patients sustained dog bites and five had cat bites; nine injuries were inflicted by domestic pets and two by stray dogs. Under aerobic/capnophilic culture conditions (systematic anaerobic culture was not performed), a total of 17 distinct bacterial isolates were recovered from wound specimens, and polymicrobial contamination (≥ 2 species) was identified in six patients (54.5%). Pasteurella multocida was isolated from 4 of 11 patients (36.4% of all cases), accounting for 23.5% of total isolates, followed by Neisseria weaveri and Staphylococcus epidermidis (each recovered from three patients, 27.3% of cases, 17.6% of isolates). Rarely isolated bacterial species including Neisseria animaloris , Neisseria zoodegmatis and Mammaliicoccus sciuri (formerly Staphylococcus sciuri) were exclusively cultured from dog bite wounds, which are infrequently reported in human clinical specimens. Fresh animal bite wounds from the Taihu Lake region appear to carry complex polymicrobial inocula dominated by Pasteurella spp., based on this preliminary case series. The identification of rarely isolated bacteria adds to the limited literature of bacteria introduced during animal bites in this geographic area, providing preliminary single-center microbiological observations for reference by emergency practitioners, though larger studies are needed before these findings can inform empirical prescribing protocols.