A Pain in the Neck

Case 1 Case 2 A 16-year old male presents to the Emergency Department with a fever of 104°F, neck pain and right sided chest pain 3 days prior he was seen at an urgent care clinic for sore throat and fever A rapid Group A Streptococcus (GAS) test was performed and was negative He was sent home with a diagnosis of viral pharyngitis A 23-year old female presents to the Emergency Department with a fever of 102.4°F, sore throat, neck pain and right hip pain 3 and 5 days prior she was seen in the Emergency Department No microbiology testing was ordered Both times she was sent home with a diagnosis of viral pharyngitis

Case 2 Case 1 An X-ray of his chest is performed Shows multiple nodules in both lungs: concern for infection Blood cultures are ordered A Computed Tomography (CT) scan of her pelvis is performed Shows gas around the hip joint and thickening of thigh muscle: concern for infection Blood cultures are ordered Culture of tissue from her right hip is also ordered

Laboratory Testing The anaerobic blood culture bottle from both patients becomes positive See case study “Of Mice and Men” for description of blood cultures A Gram stain of the bottle for each patient performed (see next slide) The blood culture bottle is sub-cultured onto anaerobic agar media and placed in the anerobic chamber for incubation

Blood culture bottle Gram stain Reported as “Pleomorphic Gram negative rods”

Anaerobic culture conditions Obligate anaerobes require special incubation conditions as even small amounts of oxygen can be toxic to growth An anaerobic glove box incubator can be used for these types of cultures. The incubator pumps in an anaerobic gas mixture (mostly nitrogen with a small amount of CO2 and H2) and contains a catalyst within the incubator space that absorbs O2 Smaller laboratories may use air tight boxes or “anaerobic” jars with catalyst pouches that absorb O2

Anaerobic glove box incubator

Anaerobic culture media Four different types of agar and a broth to enhance recovery of anaerobes were inoculated. The media is described as follows: Brucella Blood Agar - Non-selective media, most anaerobes will grow PEA (Phenylethyl Alcohol) – Selective media for Gram positive anaerobes LKV (Laked blood+ Kanamycin+Vancomycin) - Facilitates growth of Prevotella and Bacteroides sp. BBE (Bacteroides Bile Esculin) - Selective for Bacteroides fragilis group Only strict aerobes are identified further Aerotolerance of isolates must be tested by subculture and incubation in aerobic conditions

Blood bottle subculture from Patients 1&2 (after 48 hours in anaerobe chamber) Brucella Blood Agar No growth on PEA No growth on aerobic subculture (failed aerotolerance test) Split plate of LKV on left and BBE on right

Microbiology Laboratory Results Patient 1&2’s blood cultures (and the hip tissue from patient 2) grew a single anaerobic bacteria identified as: Fusobacterium necrophorum

Fusobacterium necrophorum Common flora of the mouth Opportunistic pathogen Associated with dental infections, sore throat and peri-tonsillar abscesses The most severe association is internal jugular vein thrombosis leading to bacteremia and dissemination of septic emboli, otherwise known as “Lemierre’s syndrome”

Lemierre’s Syndrome Case series published by Andrew Lemierre in 1936 Described throat infections followed by sepsis with high mortality rate (before antibiotics) It is a rare disease, but recent studies suggest incidence may be rising1, 2 Patients usually present with sore throat that progresses to neck pain and often visit the ED multiple times without a diagnosis because there is so much overlap with more common infections such as viral pharyngitis or Strep throat The clinical microbiology laboratory is instrumental as a blood culture identification of F. necrophorum guides diagnosis and follow up 1 Brazier JS et al. J Med Micro 2002 2 Ramirez S. et al. Pediatrics 2003

Patient Outcomes Both patients were diagnosed with Lemierre’s Syndrome after blood culture identification of F. necrophorum Patient 1 received the intravenous antibiotic Piperacillin/tazobactam (Zosyn) and recovered quickly Patient 2 received IV Ampicillin/Sulbactam (Unasyn) and had a more complicated course requiring multiple debridements of her infected right hip

Margaret Powers-Fletcher, PhD Erin Graf, PhD Margaret Powers-Fletcher, PhD Dr. Graf is a second year CPEP fellow at the University of Utah and ARUP Laboratories in Salt Lake City, Utah. Upon completion of her fellowship, Dr. Graf will become Assistant Director of Clinical Microbiology and Virology at the Children’s Hospital of Philadelphia. Her research interests include adaptation of next generation sequencing technologies and metagenomics for diagnosis in the clinical microbiology laboratory. Dr. Powers-Fletcher is a first year CPEP fellow at the University of Utah and ARUP Laboratories in Salt Lake City, UT. She obtained her Ph.D. in Pathobiology and Molecular Medicine from the University of Cincinnati College of Medicine. Her thesis work focused on stress response pathways of the opportunistic fungal pathogen, Aspergillus fumigatus. She has expanded on her interest in medical mycology during her fellowship, working on advanced fungal diagnostics and susceptibility testing.