Stricken with a fever and severe localized pain, a young girl is rushed to the hospital.
Mary, a healthy 7-year-old girl, suddenly began complaining of severe right-hip pain while on vacation with her parents. Assuming it was a passing childhood pain, her parents paid little attention until she started crying and was unable to bear any weight on her right leg. A doctor at the local clinic found an elevated WBC count of 16,000/µL with a marked left shift and a 103°F temperature. He advised the parents to return home immediately and take the girl to the emergency department (ED).
By the time the family arrived home more than four hours later, Mary was writhing in pain and her temperature was 104°F (even after taking acetaminophen and ibuprofen during the trip). At the ED, her BP, respirations, and neurologic signs were normal. She had no visible wounds, and urinalysis was clear. Her right hip was tender to palpation and felt warm to the touch. Plain radiographs were negative for fracture or subluxation.
Mary was admitted to the hospital. She was started on IV fluids and continued on acetaminophen alternating with ibuprofen to control her fever. Two sets of blood cultures were drawn and IV antibiotics begun. Since the origin of the fever and hip pain were still undetermined, ceftriaxone (Rocephin) was chosen as a broad-spectrum antimicrobial. A CT scan of her hip revealed an abscess and necrotic changes in the right acetabulum and femoral head.
The blood cultures were initially negative. After the abscess in the hip was percutaneously drained, this culture and the later reading on the blood cultures were positive for salmonella.
With no other family members or friends ill currently or in the recent past, infectious disease investigators from the university became concerned with the origin of Mary’s infection and began the search for its source.
After six weeks of epidemiologic analysis, it was determined that the pathogen was acquired while climbing a tree at a relative’s home in New Mexico several weeks earlier. This tree was the favorite nighttime roosting area for many birds. Culture specimens of bird droppings from the tree also grew Salmonella enteritidis. A small, unobtrusive scratch had provided an entry portal for the bacteria, which migrated and ultimately seeded in the right acetabulum.
Salmonella enteritidis is a rod-shaped, motile gram-negative Enterobacter. Named after its discovering scientist, Dr. Daniel Salmon, salmonella cause infections reportable to the CDC because of the potential for significant outbreaks. Transmitted through feces, the organism is most commonly associated in the United States with poorly cooked chicken or eggs in the food industry (although reptiles also frequently harbor the bacteria). Salmonella enteritidis has been found to silently infect the ovaries of the fowl, and thus, the eggs are infected even before the shells are formed.
Concomitantly, the GI tract and droppings also carry live bacteria. Most human S. enteritidis illnesses are confined to the GI system and produce severe but self-limiting bouts of cramping, nausea, vomiting, and diarrhea. In rare instances, the microbe migrates past the gut and becomes proliferative in a different site. Since the natural “self-cleaning” mechanism of the gut is absent in other seeding sites, these infections become much more serious and require aggressive antimicrobial intervention. Additionally, in spaces such as the acetabulum, an encapsulation effect develops as a result of the decreased blood flow and lower antibiotic-distribution capability.
Salmonella enteritidis is sensitive to ampicillin, ciprofloxacin, and trimethoprim/sulfamethoxazole. Specific antimicrobial sensitivity data can be hard to obtain, however, because culture techniques are fastidious for these bacteria. Only 50%-70% of initial blood cultures are positive in persons with salmonellosis.
In the United States, it is estimated that one in 50 persons is exposed to an S. enteritidis-contaminated egg at least yearly. While the CDC continues to work on ways to reduce this incidence, strict food-handling hygiene should be followed for any poultry-related food product.
Mary had to have the abscess in her hip surgically drained. She was in the hospital for one week with an irrigating drain in place for that time. Her ceftriaxone was changed to ciprofloxacin once the organism had been identified. She went home feeling well. The clinicians cautioned her and her family to seek immediate medical attention for any low-grade temperature in the next five years, and she has had repeated CT scans annually for three years to monitor the femoral head integrity.
Today, Mary is happy and healthy. She has had no further problems with her hip. She walks with a normal gait and her mystery illness is just a memory.