1 © Duarte, Inc. 2014

Arcanobacterium Haemolyticum: Not your typical gram positive osteomyelitis

Sarah De los Santos, BA, Talal Alzahrani, MD, Alexander Fortenko, BS, Juliana Camba, MD Department of Medicine, The George Washington University, Washington DC

Case Presentation A 30 year-old man with diabet ic peripheral neuropathy presented with a painful , erythematous, diabet ic plantar ulcer with purulent drainage , fevers and and tender inguinal lymphadenopathy. Three months prior to admiss ion -  In rural Michigan, a tree fe l l on his foot result ing in a hematoma.

One month later -  Pat ient presented with a painful , non-heal ing plantar ulcer. -  Xray: No s igns of fracture or infect ion. -  Wound care included repeated debridement due to poor heal ing

with no ant ib iot ic use .

Three days prior to admiss ion -  Pat ient presented with edematous painful le ft foot with erythema -  X-ray: Indist inct ions seen on the proximal first and second

phalanges are most l ikely secondary to trauma. Evidence of heal ing osteomyel i t is of the second dista l phalanx.

Pat ient returned for worsening symptoms, and was admitted for evaluat ion of osteomyel i t is , and intraoperat ive management His medical h istory was otherwise remarkable for methic i l l in-res istant Staphy lococcus Aureus osteomyel i t is requir ing par t ia l amputat ion of left second dista l phalanx, resolved type I I d iabetes, and obesity. He was a Franciscan monk, who is current ly preparing to be ordained. Examination, Laboratory & Imaging Studies Temp 37.6°C BP 133/93 HR 108 RR 14 SPO2 99% on Room Air The left dista l foot was erythematous and edematous, most prominently at the second dig it . On the plantar surface , there was a 3 cm x 0.5 cm x 2 mm ulcer with necrotic t issue , hyperkeratot ic borders, and serosanguinous drainage . The foot was warm and tender with no pockets of fluid or fluctuance . WBC 10.29 Segs 79% ESR 42 CRP 37.7 Left Foot Xray (F igure 1) There is swel l ing in the soft t issue of the dig its , most prominent at the second toe . There has been amputat ion of the second dista l phalanx. There is cort ica l destruct ion of the second proximal phalanx, compatible with osteomyel i t is .

Introduction Arcanobacter ium Haemolyticum , a facultatively anaerobic, pleomorphic, gram-positive rod, is a known causative pathogen for exudative pharyngitis and cutaneous infections. More rarely, it is has also been identified in more severe infections such as osteomyelitis, endocarditis, and brain abscesses. Diagnosis is often missed due to its slow growth in culture and initiation of treatment without confirmation of cause of infection.

Conclusion Gram posit ive organisms are the most common causes of osteomyelit is , include Staphylococcus Aureus , β hemolyt ic Streptococcus , and coagulase negat ive Staphylococcus. Infection by Arcanobacter ium Haemolyt icum should not be overlooked. Misdiagnosis has been shown to lead to sepsis and death. Dif ferentiat ion from other gram-posit ive organisms is essential for proper management of treatment. ” A rc a n o b a c t e r i u m H a e m o l y t i c u m ” b y ” m o s t l y * h a r m l e s s ” L i c e n s e d u n d e r a C re a t i v e C o m m o n s A t t r i b u t i o n 2 . 0 G e n e r i c ( C C - B Y 2 . 0 ) . A c c e s s e d 2 0 A p r i l 2 0 1 4 . h t t p s : / / w w w. fl i c k r. c o m / p h o t o s /2 1 9 9 7 8 9 8 @ N 0 4 Figure 2 – Growth of A. Haemoly t i cum on Trypt icase Soy Agar with sheep b lood incubated in 5% CO2 shows a f ter 72 hours . Figure 3 – Transmitted l ight h igh l ights theβhemolys is of A . Haemoly t i cum Due to its pleomorphic nature , it is di fficult to dist inguish the morphology of this organism. Distinct colony features, are seen only after 72 hours of incubation, complicating early diagnosis. Delays in diagnosis become cl inical ly relevant as penici l l in, the first- l ine for streptococcal infections has been shown to be ineffective against A. Haemolyt icum due to developed resistance . Antibiotic sensit ivity testing should be used to guide treatment.

Hospital Course Day 1 Star ted IV Vanomycin and Piperaci l l in/Tazobactam with contact isolat ion due to history of MRSA osteomyel it is Received 90 minute Hyperbaric Oxygen Treatment Incis ion, drainage , and debridement of left wound with gentle resect ion of the 2nd metatarsophalangeal joint . Wound vacuum was set in place . Antibiot ics were switched to IV Vancomycin and Cefepime to include Psuedomonas coverage . Day 3 Pathology showed acute on chronic osteomyel it is of the second metatarsal and phalanx. Four wound cultures grew gram posit ive baci l l i with few diphtheroids. Antibiot ics were switched to IV Cl indamycin. Blood and urine cultures were negat ive Day 6 Biochemical analys is with API Coryne test ing kit and Vitek 2 ANC card confirmed growth of A. Haemolyt icum that is sensit ive to erythromycin, azithromycin, gentamicin, and cl indamycin. A PICC l ine was placed. The wound vacuum was removed, and he underwent fur ther debridement as wel l as primary closure of the wound. Day 8 He was discharged on 2 weeks of IV Cl indamycin. and transit ioned to a 4 week course of oral Cl indamycin

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