Helcococcus kunzii isolation from prosthetic joint infection

Abstract number: 1733_655

Balejová M., Fialová M., Piskunová N., Trubac P., Motlová J.

Objective: Identification of a rare isolate –Helcococcus kunzii – from prosthetic joint infection is presented.

Methods: Perioperative specimens from prosthetic joint infection were processed according to standard laboratory practice. Tissue specimens were homogenised in thioglycolate broth, components of explanted prosthesis were sonicated in Ringer solution. Homogenised and sonicated fluids were centrifuged and the sediment used for Gram staining and culture. Culture media, both solid and liquid, were incubated at 35–37°C aerobically and anaerobically for 7 days, while daily examined. The identification of the microorganism was performed by conventional methods and API 20 Strep set (bioMérieux). DNA sequencing of the 16S rRNA gene was performed using ABI Prism 310 Genetic Analyser (Applied Biosystems, Foster City, CA, USA). Nucleotide sequences were analysed with MegAlign software (DNASTAR, Regent St. Madison, WI, USA) and aligned to EMBL/GenBank. Antimicrobial susceptibility testing was determined using disc diffusion method and E-test system (AB Biodisk).

Results: Direct smear examination from the tissue specimen showed only erythrocytes. After 72-hour of incubation, growth of pinpoint, translucent, non-haemolytic colonies appeared on 5% sheep blood agar. A subculture from the thioglycolate broth yielded the same bacterial growth. A Gram stain of the isolate revealed Gram-positive cocci of various sizes in clusters. The identification in API 20 Strep (bioMérieux) resulted in profile no. 4102411 –Aerococcus viridans (75.6%). DNA sequencing of the 16S rRNA gene of the isolate showed 99.8% similarity with H. kunzii. The strain was susceptible to ampicillin, erythromycin, clindamycin, vancomycin, rifampin and resistant to ciprofloxacin, gentamicin. The MICs of penicillin and clindamycin, determined by the E-test system were 0.500 and 0.032 mg/L, respectively.

Conclusions:H. kunzii is a rare isolate in clinical specimens. Identification of this bacterium on the basis of phenotypic tests is difficult. Absence in databases in the most of the commercial products makes impossible to identify this organism by those means. DNA sequencing of the 16S rRNA gene identified the aetiologic agent of prosthetic joint infection in our case.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
Back to top