Coagulase-negative staphylococci (CNS) species identification is still
difficult for most clinical laboratories. The scheme proposed by Kloos
and Schleifer and modified by Bannerman is the reference method used
for the identification of staphylococcal species and subspecies;
however, this method is relatively laborious for routine use since it
requires the utilization of a large number of biochemical tests. The
objective of the present study was to compare four methods, i.e., the
reference method, the API Staph system (bioMérieux) and two
methods modified from the reference method in our laboratory
(simplified method and disk method), in the identification of 100 CNS
strains. Compared to the reference method, the simplified method and
disk method correctly identified 100 and 99% of the CNS species,
respectively, while this rate was 84% for the API Staph system.
Inaccurate identification by the API Staph method was observed for
Staphylococcus epidermidis (2.2%), S. hominis (25%), S. haemolyticus
(37.5%), and S. warneri (47.1%). The simplified method using the simple
identification scheme proposed in the present study was found to be
efficient for all strains tested, with 100% sensitivity and specificity
and proved to be available alternative for the identification of
staphylococci, offering, higher reliability and lower cost than the
currently available commercial systems. This method would be very
useful in clinical microbiology laboratory, especially in places with
limited resources
