Macrolide/fluoroquinolone‐resistant Campylobacter jejuni‐induced cellulitis in a patient with X‐linked agammaglobulinaemia successfully treated with carbapenem

Dear Editor, Cellulitis is a bacterial infection in the deep dermal layer and subcutaneous tissue. It usually manifests as erythema, tenderness, and swelling of the skin. Streptococcus pyogenes and Staphylococcus aureus are known as major causes of cellulitis. Campylobacter jejuni is one of the most common causes of foodborne enteric infections in developing countries and may cause refractory cellulitis in immunocompromised patients. Here we report a case of multidrug-resistant C. jejuni cellulitis in an X-linked agammaglobulinaemia patient. A 42-year-old male was referred to our department with a 6-month history of unresolved swelling in the right lower leg. The patient was diagnosed with X-linked agammaglobulinaemia at 3 years of age and had undertaken monthly intravenous infusions of immunoglobulin. He also had been treated with clarithromycin (200 mg/day) for chronic bronchitis and chronic sinusitis for over 10 years. During our physical examination, a diffuse erythematous lesion with tenderness on the right lower leg was observed (Figure 1A). Laboratory examinations showed elevated C-reactive protein (CRP) (7.44 mg/dl; reference value: 0–0.14 mg/dl), but a white blood cell count within the normal range (6600/μl; reference value: 3300–8600/μl). The skin lesion was diagnosed as bacterial cellulitis, and we started antibiotic treatment with cefaclor (750 mg/day). However, the lesion did not improve. We then started the administration of oral minocycline (200 mg/day) for 30 days; however, the patient's skin symptoms appeared intractable. A blood culture test detected C. jejuni that was resistant to macrolides and fluoroquinolones. We changed the treatment to intravenous meropenem (1000 mg/day) (Figure 1B). After 6 days, the symptoms of cellulitis were considerably relieved, along with decreases in CRP levels (Figure 1C). At that time, C. jejuni was not detected in blood culture tests. We continued to administer intravenous meropenem for a total of 3 weeks. The cutaneous symptoms did not recur for 3 months without any systemic antibiotics. Contrast-enhanced computed tomography of the abdomen and pelvis revealed no specific findings in the gastrointestinal tract. We also performed a colonoscopy to find a possible route of infection for C. jejuni. However, the colonoscopy showed only colorectal adenoma and a rectal polyp. Further, we performed an echocardiography, which showed no abnormal findings. To investigate the characteristics of C. jejuni-related cellulitis in immunocompromised hosts, we reviewed similar reports in the literature and identified nine cases (Figure 1D). The mean age was 25.6 years (range 17–42 years), with the lower extremities being involved in all cases. Macrolides were effective in 55% (5/9) of the cases. Due to antimicrobial resistance, the administration of carbapenem, which is a broad-spectrum antibiotic, was necessary in 22% (2/9) of cases. Macrolides and fluoroquinolones have been reported as effective against Campylobacter infections. However, strains of C. jejuni resistant to these drugs have been detected in immunocompromised hosts. Lehtopolku et al. clarified that most macrolideresistant strains are susceptible to both meropenem and imipenem treatments. Therefore, we changed the antibiotic to meropenem in the present case. Although there is no established evidence for the effectiveness of maintenance therapy against macrolide/fluoroquinolone-resistant Campylobacter infections, cases successfully treated using antibiotics such as fosfomycin and aminoglycoside have been reported. In conclusion, cellulitis in immunocompromised patients can be caused by multidrug-resistant C. jejuni. In treatment-resistant C. jejuni infections, changing the antibiotic to carbapenem could be effective.