Salmonella osteomyelitis: A rare extraintestinal manifestation of an endemic pathogen

Case 1

An 80-year-old male patient came to the orthopedics outpatient department with chief complaints of acute pain and restriction of movements in the right knee for 5 days. The patient did not give any history of fever over the preceding months. There was no history of trauma, prior surgery, abdominal discomfort, or any illness suggestive of enteric fever. Local examination of the right knee showed red, swollen joint with severe tenderness and the movements were painfully restricted. The laboratory findings were hemoglobin 12.8 g/dl and white blood cell count 12,180 cells/cu. mm with neutrophilic leukocytosis. Erythrocyte sedimentation rate (ESR) was 32 mm/h. X-ray right knee showed age-related early osteoarthritic changes as depicted in Figure 1. Pus was aspirated from the knee joint and was inoculated in brain heart infusion broth, nutrient agar, 5% sheep blood agar, and MacConkey agar and incubated overnight aerobically. Gram-stained smear of pus showed plenty of pus cells and Gram-negative bacilli. Aerobic culture yielded S. enterica subspecies enterica serovar Typhi using conventional methods and serotyping (Difco, Becton and Dickinson, New Jersey, USA).[6] Nonlactose-fermenting colonies obtained on MacConkey agar have been shown in Figure 2.

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Figure 1

Anteroposterior and lateral views of X-ray right knee showing age-related early osteoarthritic changes

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Figure 2

Nonlactose-fermenting colonies obtained on MacConkey agar

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The isolate was found to be susceptible to ampicillin, chloramphenicol, ciprofloxacin, cefotaxime, ceftriaxone, cefepime, piperacillin-tazobactam, and amoxicillin-clavulanic acid by Kirby–Bauer disk diffusion method.

Blood culture, Widal test, and stool culture were simultaneously performed to search for foci of infection. Blood sample of this patient was subjected to aerobic culture by BACTEC 450 automated blood culture system (Difco, Becton and Dickinson, New Jersey, USA) and was found sterile. Both Widal test and stool culture were nonsignificant.

Treatment with ciprofloxacin 500 mg twice daily was instituted for 3 weeks along with repeated aspirations. On follow-up, the patient was relatively asymptomatic.[7]

Case 2

A 17-year-old male patient presented with complaints of backache in the lumbar region for 1 month and reduced sensation in both lower limbs. On physical examination, the patient was afebrile with excessive paraspinal muscle spasm and lumbar lordosis. There was severe tenderness over L2–L5 region with restriction of movements. Neurological examination revealed sensory deficit below L4 level bilaterally, but there was neither bowel/bladder involvement nor saddle anesthesia. The total leucocyte count, ESR, and C-reactive protein were found to be 12,540 cells/cu. mm, 92.5 mm/h, and 14 mg/L, respectively. Figure 3 shows X-ray spine which revealed paradisical erosions at the level of L3–L4 with the reduction of disc spaces. Magnetic resonance imaging (MRI) of dorsolumbar spine showed spondylodiscitis at L2–L5 and epidural collection at L4–L5 level as depicted in Figure 4.

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Figure 3

Preoperative X-ray lateral view showing reduction of disc spaces between L4 and L5 with irregularity of end plates

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Figure 4

Preoperative T2-weighted magnetic resonance imaging of the patient showing spondylodiscitis at L4–L5 level with destruction of intervertebral disc, epidural collection, cord compression, and edema

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Correlating patient's history and radiological findings, a provisional diagnosis of Pott's spine was made, and antitubercular therapy (ATT) was started. On the 5^th day of admission, the patient gave a history of 2–3 episodes of passing loose stools with blood which subsided on its own. Keeping in mind the possibility of any pathology of gastrointestinal tract coexisting with the spinal condition, a detailed history was taken. On repeated history taking, it was revealed that the patient had fever and abdominal pain 3 months before developing back pain. He was prescribed antipyretics and analgesics which provided partial relief, but subsequently, he had loss of appetite and weight. Microscopic examination of stool sample did not reveal the presence of ova or cysts. Blood samples were collected from three different sites and subjected to aerobic culture using BACTEC-450-automated blood culture system (Becton and Dickinson, New Jersey, United States). S. enterica subspecies enterica serovar Typhi was isolated from all three samples. Identification was confirmed using conventional methods and serotyping using antisera (Difco, Becton and Dickinson, New Jersey, USA). Moreover, immunoglobulin M (IgM) immunochromatographic card test (Typhidot IgM, Enteroscreen – WB, Zephyr Biomedicals, Tulip Diagnostics Pvt. Ltd., Goa, India) was also positive.

The patient underwent open disc biopsy and decompressive laminotomy at L4–L5 region. Intraoperatively, aspirated pus was negative for acid-fast bacilli, but on aerobic culture, S. Typhi was isolated which was sensitive to aminoglycosides, cephalosporins (including ceftriaxone and cefuroxime), and β-lactam drugs by Kirby–Bauer disk diffusion method. Mycobacterial culture and Gene X-pert found no evidence of tuberculosis. ATT was stopped immediately, and the patient was started on injection cefuroxime for 3 weeks on inpatient basis which was continued orally for a total of 6 weeks. The patient responded well to treatment and showed rapid symptomatic and neurological improvement. Follow-up after 6 months showed that the patient was asymptomatic with no neurological deficit.[8]

Case 3

A 24-year-old male was admitted with complaints of significant pain and swelling in the right thigh extending up to the knee for 3 months. He also had low-grade fever of 2 months’ duration. His symptoms had worsened over the last 1 month as a result of which he found it exceedingly difficult to maintain an upright posture and walk. He also gave a history of diarrheal illness 3 months back, with complete recovery within 6–7 days without any medication. There was no history suggestive of hemoglobinopathy or any other underlying comorbidity. Conservative management by local health care practitioners using analgesics and physiotherapeutic measures over several weeks brought no relief to his current ailment.

At the time of presentation, the patient was conscious, oriented, and afebrile. Physical examination revealed tenderness and swelling over distal two-third of the right thigh over anterior aspect extending up to the knee joint. No scar, sinus, ulcer, or discharge was visible. On palpation, temperature was raised over the swelling, and distal pulses were palpable.

Complete haemogram revealed hemoglobin 11.3 g/dl, total leucocyte count of 21,720/cu. mm (neutrophils – 89.8%), platelet count 2.92 lakhs/cu. mm, and ESR 65 mm/h. Liver and kidney function tests were within normal limits. X-ray showed ill-defined irregular intramedullary radiolucency over distal two-third of femur suggestive of osteolytic lesions with gross periosteal reaction and internal sclerotic bone fragments likely to be a sequestrum as depicted in Figure 5. Figure 6 shows MRI findings which revealed the presence of large intramedullary collection with sclerotic bone fragments at distal end of femur with marked synovial effusion and periarticular soft tissue edema suggestive of osteomyelitis.

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Figure 5

Anteroposterior and lateral views of X-ray showing ill-defined irregular intramedullary radiolucency over distal two-third of the right femur suggestive of osteolytic lesions

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Figure 6

Magnetic resonance imaging showing large intramedullary collection with sclerotic bone fragments at the distal end of the right femur

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Presumptive diagnosis of acute on chronic osteomyelitis of the right femur was made and cortical window with decompression surgery was planned. Cortical window was made with osteotome and blood-tinged pus was found in-between muscle planes and inside intramedullary cavity. Postoperatively, intravenous (IV) cefuroxime was given.

Pus from knee joint cavity, muscle plane, and intramedullary cavity showed growth of S. enterica subspecies enterica serovar Typhi identified by conventional methods and serotyping using antisera (Difco, Becton and Dickinson, New Jersey, USA). The isolate was sensitive to ampicillin, cotrimoxazole, ofloxacin, ciprofloxacin, ceftriaxone, and cefotaxime by Kirby–Bauer disk diffusion method. Aerobic blood culture was found to be sterile. The patient showed remarkable improvement postoperatively and was discharged while still on treatment with IV Ceftriaxone 2 g BD for 2 weeks.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.