Not just simple cellulitis: a case report of polymicrobial Aeromonas infection from rural Queensland

The Gram-negative organism Aeromonas is found in freshwater and marine environments and can cause a range of disease in humans, most commonly gastrointestinal illness and soft tissue infections. The severity of soft tissue infections can vary, ranging from cellulitis to rapidly spreading soft tissue infection. Prompt recognition of this pathogen is needed as empirical antibiotics for cellulitis generally do not provide sufficient cover for Aeromonas. Additionally, while cellulitis is generally managed medically, early surgical intervention may be required when Aeromonas is the causative pathogen.

A Caucasian male aged 39 years injured his right foot falling in a creek bed in the Darling Downs region of rural Queensland, sustaining a laceration in the webbing between his first and second toes. He was seen in two rural hospitals following this event, with oral antibiotics prescribed following his second presentation to cover for a localised soft tissue infection. Circumstances meant he did not take these, and he finally presented to a third hospital after noting erythema tracking up his leg and discharge emanating from the wound on his foot. He was admitted and commenced on empirical antibiotics, however severity of the infection necessitated surgical team involvement and multiple debridements. Due to the extent of tissue removal, a skin graft was required. Intraoperative specimens revealed polymicrobial Aeromonas as the causative pathogen.

This case report documents a polymicrobial soft tissue infection in a systemically well young male requiring prompt surgical intervention, even without systemic symptoms of illness. Lack of early recognition of risk factors for infection may have delayed appropriate antibiotic therapy. It highlights the importance of early recognition and appropriate antibiotic cover to prevent spreading infection in individuals in whom Aeromonas may be the suspected pathogen. Empirical antibiotics for cellulitis generally do not include the agents to which Aeromonas is susceptible, hence guidelines recommend a regime of trimethoprim-sulfamethoxazole or ciprofloxacin in addition to either dicloxacillin or flucloxacillin. Initiation of appropriate antibiotics earlier in this case may have prevented the need for surgical intervention. This case also demonstrates that early surgical referral and intervention may be warranted in suspected Aeromonas infections.