Identification of staphylococci by using commercial kits STAPHYtest 24 and API Staph

Abstract number: P1386

Sedlacek I., Petras P., Pliskova Pakrova E., Skapova T., Jancova J., Jezek P., Machova I.

Objectives: Staphylococci represent a substantial part of the surface microflora of mammals and birds (skin, skin glands, mucous membranes) and some Staphylococcus species, mainly S. aureus, are found frequently as aetiological agents of a variety of human and animal infections. The species identification of staphylococci based on biotyping is still commonly performed in routine clinical laboratories. The aim of presented study was the comparison of species identification of staphylococci by using two commercial biochemical systems.

Methods: A total of 195 staphylococcal cultures were evaluated in this comparative study including 40 reference CCM strains and 155 clinical isolates obtained from 3 different microbiological laboratories. All cultures were identified by standard procedure (STAPHYtest 24 and API Staph) according to manufacturer's instruction. In case of discrepant identification results obtained by commercial kits the final identification was performed in the National Reference Laboratory for Staphylococci based on a large set of tests.

Results: STAPHYtest 24 kit successfully identified to the species level 160 cultures (82%) of tested, remaining 27 strains (14%) were identified to the genus level only and 8 strains (4%) stayed unidentified or misidentified. Applying of additional tests recommended by identification software (TNW v. 7.0) improved species identification to 94% when 6 strains (3%) were misidentified and next 6 strains (3%) stayed identified to genus level only. API Staph kit surprisingly identified only 103 cultures (53%) to the species level. Great number of strains, 71 of 195 studied (36%), was identified by API Staph just to genus level and 21 strains (11%) were not identified or misidentified. Applying of additional tests according to identification software (apiweb) improved correct species identification to 84%. Unfortunately this step increased false identifications to 30 cases and the high number of misidentified staphylococci represent a great problem of API Staph kit or identification software apiweb.

Conclusion: Our results proved usefulness of the new identification kit STAPHYtest 24 for reliable identification of staphylococci. In our view the STAPHYtest 24 is superior to API Staph as regards of identification efficacy as well as user friendly.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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