Acta Demato-Venereologica 98-3CompleteContent | Page 22

378 See See also also Commentary, Commentary, p. 304 p. 304 SHORT COMMUNICATION Infectious Cellulitis Caused by Streptococcus halichoeri Pascal DEL GIUDICE 1,2 , Céline PLAINVERT 3 , Thomas HUBICHE 1,2 , Asmaa TAZI 3,4 , Agnès FRIBOURG 1,2 and Claire POYART 3,4 Infectiology and Dermatology and 2 Bacteriology Laboratory, Hospital of Fréjus-Saint-Raphël, 240 avenue Saint Lambert, FR-83600 Fréjus, National Reference Center of Streptococcus, Universitary Hospital Paris Center, site Cochin, AP-HP, Team «Barrière et Pathogènes», Cochin Institute, Inserm 1016, CNRS UMR 8104, 4 Paris Descartes University, Paris, France. E-mail: [email protected] 1 3 Accepted Nov 2, 2017; Epub ahead of print Nov 7, 2017 Infectious cellulitis is mainly caused by Streptococcus pyogenes or Staphylococcus aureus (1, 2). Other less fre- quently isolated bacteria include Pasteurella from animal bites, non-typable streptococci or Bacillus anthracis in intravenous drug users, Vibrio spp. or Aeromonas spp. due to skin wounds in sea water (1, 2). We present here, to our knowlegde, the first human case of a cellulitis caused by a new pathogen, Streptococcus halichoeri. 2 Gram-positive card system (bioMérieux, Marcy l’Etoile, France) and S. agalactiae (unacceptable profile) by Api 20 STREP gallery (bioMérieux, Marcy l’Etoile, France). The bacteria grouped with Lancefield type B antisera (Streptococcal Grouping Latex Kit, DiaMondial, Vienna, Austria). Recurrence of the endocarditis was eliminated by normal endoesophageal and transthoracic echograp- hies. The outcome was favourable after 15 days’ treatment with 100 mg/kg amoxicillin. All the strains isolated during both episodes were sent to the French Reference Center for Streptococci for expert analysis (CNR-Strep; https://www.cnr-strep.fr/). Strains isolated during the first episode grew beta-haemolytic colonies on horse-blood agar CASE REPORT plates. The bacteria were catalase-negative, Gram-positive cocci, in chains, Lancefield grouping with type B antisera (Remel™ An 84-year-old man was hospitalized due to bacterial cellulitis PathoDxtra™ Strep Grouping Kit), giving typical orange pigmented of his left thigh in November 2015. His past medical history colonies on Granada-based media plate (Granada™, bioMérieux, was marked by obesity, diabetes mellitus treated with gliclazide, Marcy l’Etoile, France) and identified as S. agalactiae (score 2.43) insulin and metformin, dyslipidaemia treated with atorvastatin, by MALDI-TOF MS (Matrix Assisted Laser Desorption Ionisation hypertension treated with bisoprolol and perindopril, hyperuri- Time Of Flight) mass spectrometry (Bruker ™ ). Molecular characte- caemia treated with allopurinol, atrial fibrillation, and prostatic rization identified a capsular serotype III strain (3). Antimicrobial adenocarcinoma treated with surgery and radiotherapy. Sixteen drug-susceptibility testing performed according to the European months earlier he had been hospitalized due to cellulitis in the Committee on Antimicrobial Susceptibility Testing guidelines same location. Streptococcus agalactiae was isolated from blood (http://www.eucast.org) characterized the strains as susceptible to cultures. Cardiac ultrasonography revealed left-sided endocarditis penicillin (minimum inhibitory concentration (MIC) ≤ 0.25 mg/l), and the patient was treated with parenteral amoxicillin (100 mg/kg) erythromycin, clindamycin, levofloxacin, tetracycline, and linezo- associated with gentamicin (3 mg/kg) for 15 days, followed by oral lid. Strains isolated from blood culture and wound sample during amoxicillin alone for one month. The outcome was favourable. An the second episode both grew non-haemolytic and non-pigmented infected chronic ulcer of the left leg was thought to be the likely colonies on horse-blood agar plates and Granada™ plates, respecti- route of entry of infection. vely. Both bacteria were catalase-negative and Gram-positive cocci The new hospitalization, 16 months later, was marked by cel- in chains. They were identified as S. halichoeri (score 2.21 and 2.43, lulitis of the thigh in the same location with persisting chronic respectively) by MALDI-TOF MS and as S. suis serotype 1 (87% ulc eration of the left leg (Fig. 1). On admission, the patient’s body probability) by VITEK 2 Gram-positive card system (bioMérieux, temperature was 38.5°C, associated with a large erythematous Marcy l’Etoile, France). MALDI-TOF MS allows a rapid and skin plaque on his thigh consistent with bacterial skin cellulitis. precise microbial identification and strain typing. It is an analytical The patient was treated empirically with intravenous amoxicillin technique in which chemical compounds are ionized into charged (100 mg/kg). Blood cultures, and samples from the leg ulcer, molecules and the ratio of their mass to charge (m/z) is measured. grew non-haemolytic colonies on sheep-blood agar plates. Gram- A characteristic spectrum, called a peptide mass fingerprint (PMF), staining revealed Gram-positive cocci, in chains. The identification is then generated. Identification of microbes by MALDI-TOF MS results were discordant: S. pyogenes (91% probability) by VITEK is carried out by comparing the PMF of the unknown organism with the PMFs in the database (4). Molecular identification at the species-level was carried out by sodA gene and 16S ribosomal RNA gene sequencing (5, 6). Sequence analysis yielded 100% identity over 438 bp with the sodA gene se- quence of the S. halichoeri strain SS1939 (KP890268 NCBI database) and 99% identity over 971 bp with the 16S ribosomal RNA gene of the S. halichoeri type strain SS1844 (KP851845 NCBI database), allowing definite identification of S. halichoeri. Anti- microbial drug-susceptibility testing characterized the strains as susceptible to penicillin (MIC≤0.25 mg/l), levofloxacin, and linezolid and resistant to erythromycin, clindamycin and tetracycline, due to the presence of erm(B) and tet(O) antibiotic-resistant genes, respectively (7). Thus, the second episode was not a recurrence of S. agalactiae infection, but Fig. 1. Clinical characteristics. Cellulitis of the left thigh, with chronic ulceration of the lower leg. bacteraemic cellulitis due to S. halichoeri. doi: 10.2340/00015555-2837 Acta Derm Venereol 2018; 98: 378–379 This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2018 Acta Dermato-Venereologica.