Lemierre Syndrome Caused by Arcanobacterium haemolyticum Alone in a Healthy Man
A 37-year-old, previously healthy man came into the emergency department of Chonnam National University Hospital with a 3-day history of painful left neck swelling, myalgia, asthenia, and fever. The patient also complained of lower back pain, chest tightness, dyspnea, and cough. He had been treated with cephradine YuHan (YuHan Corporation, Korea, 500 mg three times per day, orally, for 3 days) owing to complaints of a sore throat at another primary clinic. He had no history of intravenous drug abuse and no risk factors for HIV infection. On physical examination, he had a temperature of 38.9℃, a respiratory rate of 28 breaths/min, a pulse of 100 beats/min, and blood pressure of 80/40 mmHg. His throat examination showed mild erythema. The anterior border of the left sternocleidomastoid muscle was very tender on palpation. Breath sounds were clear and there was no heart murmur. A maculopapular rash was observed on the trunk. The results of laboratory tests on admission were as follows: leukocyte count, 2,500 (4,800-10,800 cells/µl) with 79.2% neutrophils; hemoglobin, 13.0 (12-18 g/dl); hematocrit, 36 (37-52%); platelet count, 22×103 (130-450×103/µl) without morphologic changes; alanine aminotransferase, 65 (<37 U/L); aspartate aminotransferase, 38 (<37 U/L); lactate dehydrogenase, 486 (<37 U/L); total bilirubin, 3.98 (<0.6 mg/dl); total protein, 5.2 (6-8.3 g/dl); albumin, 2.6 (3.5-5 g/dl); ESR, 40 (<20 mm/h); and CRP, 20.2 (<0.5 mg/dl). His arterial oxygen pressure (PaO2) was 84.6 mmHg. The serology results were negative for Mycoplasma pneumoniae, Chlamydia pneumoniae, human immunodeficiency virus, hepatitis B virus, and hepatitis C virus. Two sets of aerobic and anaerobic blood culture samples were taken from two different sites. The chest radiography revealed a multiple patchy infiltration and a contrast-enhanced computed tomography scan demonstrated multiple pulmonary consolidation with some internal cavitations predominantly in the subpleural, lower, and peripheral lung. A transthoracic echocardiogram did not show any valvular lesions. Empiric treatment was started with ceftriaxone (Boryung Pharm Co. Ltd, Korea) 2 g every 24 hours and metronidazole (JW Pharmaceutical, Korea) 500 mg every 8 hours.\nOn the third day, the patient was still febrile and the signs of sepsis persisted. A computerized tomographic angiogram (CTA) of the neck was performed, showing an ill-defined non-enhancing filling defect in the left IJV consistent with thrombophlebitis with a 1.9×1.1 cm sized peritonsillar abscess ().\nOn the seventh day, his condition deteriorated, and his pulmonary symptoms worsened. A chest X-ray was done, showing increased infiltration on both lower lung fields and the development of pleural effusion. A diagnostic thoracentesis was done that resulted in exudate. However, no organisms were cultured from the pleural fluid.\nGram-positive bacilli were found in two sets of blood cultures obtained initially and were identified as A. haemolyticum by use of a VITEK II automated system (bioMérieux, Marcy l'Etoile, France). The isolate was nonmotile, non-acid-fast, catalase-negative, oxidase-negative, and urease-negative. A reverse CAMP test showed a positive result. 16S ribosomal RNA gene sequencing was used to confirm the result. The 5'-AGTTTGATCCTGGCTCAGGTATTGCCGCCGCTGCTG-3' primer was used to amplify the 16S rRNA gene. We found 99% homology in 157 bp of 16S rRNA gene sequences of the isolates and A. haemolyticum (Gen-Bank accession number CP002045.1). Although there is no standardized method for studying the antibiotic susceptibility of A. haemolyticum, the diffusion disc-plate method was performed in this case. Susceptibility was approximated by using the zone diameter interpretive standards for Streptococcus spp. established by the Clinical and Laboratory Standard Institute (Performance Standards for Antimicrobial Susceptibility Testing; Twenty-first Information supplement M100-S21). The isolates showed susceptibility only to ciprofloxacin, gentamicin, vancomycin, and chloramphenicol but resistance to penicillin, erythromycin, clindamycin, tetracycline, and trimethoprim/sulfamethoxazole.\nAntibiotics were changed to intravenous vancomycin 1 g every 12 hours and gentamycin 100 mg every 8 hours. Simultaneous anticoagulation therapy was started with intravenous heparin.\nAfter that, the patient became afebrile and the other signs of sepsis improved. After 4 weeks of antibiotics therapy, a follow-up CTA of the neck was performed, which and showed the disappearance of the peritonsillar abscess and left IJV thrombosis with improvement of perivascular inflammatory change.