A 79-year-old man presented himself with a clinical picture that was assessed as a case of erysipelas. The patient’s medical history included atrial fibrillation, obstructive sleep apnea syndrome (OSAS), treatment for latent tuberculosis in 2021 and two episodes of transitional ischemic attack (TIA). No history of immunosuppression was recorded. The patient had travelled to Germany three weeks before his debut of symptoms but had never travelled outside of Europe during his lifetime.

Day 1 of symptoms (2022-06-30), the patient was visiting a lake in northern Sweden, close to the Swedish town, Jokkmokk, where he was bitten by a horsefly (Tabanidae family) on his right foot. Hours afterwards, the patient experienced redness, swelling and pain in the skin in association with the wound (Fig. 1A).

Day 2, the patient became febrile, and the area of inflammation had expanded proximally to the lower part of the same leg with erythematous rashes (Fig. 1B). The patient subsequently went to a primary health care center, where he was prescribed phenoxymethylpenicillin (PcV) for the case of erysipelas, an infection usually caused by Streptococcus pyogenes/Streptococcus dysgalactiae [14]. Later the same day, the patient went to the emergency clinic at Sundsvall Hospital with more severe symptoms, where a C-reactive protein (CRP) level of 91 mg/L was observed in blood samples. The clinical assessment at the hospital was, once again, erysipelas. Blood cultures were taken, and treatment was started with 1 dose of 3 g benzyl-penicillin given intravenously. The patient was sent home with continued phenoxymethylpenicillin treatment of 1 g x3.

Day 3, blood cultures returned positive, showing Gram-negative bacteria, and the patient was contacted for a new assessment. The clinical status of the leg had worsened, with an increased area of redness and swelling (Fig. 1C). CRP had increased to 238 mg/L and leukocyte count to 26 × 109/L (reference: 3.5–8.8 × 109/L). The patient was given 2 g of ceftriaxone intravenously and sent home with ciprofloxacin 500 mg x2, in addition to the current phenoxymethylpenicillin treatment. The patient was also scheduled for an assessment at the Department of Infectious Diseases two days later and received instructions to seek the emergency clinic upon any sign of worsening symptoms.

Day 4, in line with given instructions, the patient sought the emergency department for increasing pain and redness in the leg. The patient was then admitted to the Sundsvall hospital as an inpatient of the clinic for Infectious Diseases, with a treatment regimen consisting of cefotaxime 2 g x3 intravenously and clindamycin 300 mg x3 orally. At admission, the patient had a blood pressure of 105/59, CRP of 285 mg/L and a temperature of 37.7 degrees Celsius.

Day 5, blood cultures were identified as C. violaceum. Susceptibility tests were completed: cefotaxime was discontinued in favor of ciprofloxacin, due to the resistance pattern; ciprofloxacin was given at two doses of 400 mg intravenously and one dose of 500 mg orally.

Day 6, the clinical picture had improved, with decreased swelling, redness, and pain, along with loss of fever and CRP of 105 mg/L. The patient was then discharged from the hospital with a treatment regimen consisting of ciprofloxacin 500 mg x2 and clindamycin 300 mg x3, combined with continuous follow-up at the department for Infectious Diseases at Sundsvall Hospital.

One week after discharge, the clinical picture was still improving and clindamycin was ended and, after another 2 days, ciprofloxacin was replaced by trimethoprim/sulfamethoxazole 800 mg/160 mg x2, due to drug-induced skin rash.

After 8 more days, the clinical picture of the patient’s leg was close to habitus (Fig. 1D). The patient experienced no further symptoms and antibiotic treatment was ended with scheduled follow-up for blood-cultures.

Timeline of the clinical presentation of the infection. A) Day 1 of symptoms, hours after the bite of a horsefly. B) Day 2 of symptoms, spreading of inflammation and rashes C) Day 3 of symptoms. After approximately 24 h of PcV treatment and 3 g of benzylpenicillin. D) 17 days after discharge with peroral antibiotics (see above)