Case Presentation: A 77-year-old man with a history of atrial fibrillation presented to the emergency department due to increased erythema, swelling, and tenderness of his left elbow and foot. He had associated fever and altered mental status. These symptoms had progressed despite outpatient use of oral cephalexin initiated for cellulitis. A week prior to admission, the patient had been swimming in a Delmarva Peninsula river when he fell on the boat dock and sustained a laceration to the plantar surface of his left foot. Initial imaging of his foot, ankle, and arm supported cellulitis without complications of abscess or necrotizing infection. Based on the clinical findings and the patient’s pertinent history of water exposure, antibiotics were broadened to ceftriaxone and doxycycline to cover additional gram-negative organisms such as Vibrio spp.. Initial blood cultures grew gram negative rods, however final identification of the gram negative took over 21 days, during which time pathogens of major public health concern such as Burkholderia pseudomallei were being considered. During this time, the patient did improve, and he was discharged to home on intravenous ceftazidime and oral doxycycline for at least two weeks while awaiting final cultures. One week later, preliminary speciation revealed Haematospirillum jordaniae.
Discussion: Haematospirillum jordaniae is an environmental gram-negative bacillus with emerging potential for pathogenicity. This spiral-shaped aerobe has been isolated and reported in literature less than 20 times. According to the CDC, all reported cases occurred in men and in lower leg injuries. This novel bacterium frequently contaminates water sources and has been isolated as far away as Slovenia and China. Going forward, broadening the differential even beyond the normal water borne pathogens considered such as Vibrio, Pseudomonas, and Burkholderia spp. will be necessary. Additionally, antibiotic stewardship is an ongoing necessity in reserving appropriate and strong antibiotics when resistant and new bacteria like this are discovered. An alphaproteobacterial, H. jordaniae is in the same family as Rhodospirallales spp. and Novospirilium. Linked by specific 16S rRNA gene fragments, these species have been isolated in dye wastewater from the textile industry. While these bacteria provide options to degrade refractory dyes and organic chemicals, they pose a threat to humans if these pollutants extend beyond the wastewater into the environment. Already, bacteria including H. jordaniae appear in major waterways such as the Delmarva Peninsula, which suggests an even stronger predilection for widespread pestilence among water-adjacent organisms. The impact of human activities in the creation and spread of environmental pathogens marks an ongoing battle in the intersection of environmentalism and health that cannot be ignored.
Conclusions: Cellulitis commonly causes infection and sepsis. Typical pathogens to consider include beta hemolytic streptococci and Staphylococcus aureus. Importantly, environmental and animal exposures increase the potential for additional pathogens, and thereby dictate the need to change antibiotic management. A thorough history, including environmental exposures, and broad differential diagnosis are necessary to identify and swiftly treat less common pathogens. In this case of cellulitis, these factors eventually led to the diagnosis of a rare and emerging water-borne pathogen.