COMPARATIVE EVALUATION OF BIOMERIEUX VITEK MS, BRUKER MICROFLEX MS,
AND API AN FOR THE IDENTIFICATION OF CLINICALLY SIGNIFICANT ANAEROBES
Сравнительная оценка bioMérieux VITEK MS, MS BRUKER Microflex,
и API для идентификации клинически значимых анаэробов.
Вывод: обе автоматизированные системы работают отлично предоставляя точные результаты ID на 48 -
72 часов раньше, чем метод CPA. Следует отметить что bioMérieux VITEK MS лучше идентифицирует анаэробы
встречаются в клинических образцах нашей больницы. С точки зрения удобства, bioMérieux VMS показала себя лучше,
чем Bruker MMS, тем не менее обе системы могут быть легко включены в рутинные диагностические процедуры.
Rotimi, V.O.;1,2* Shahin, M.;2 Jamal, W.;1,2 Pazhoor, A.;2
1Faculty of Medicine, Kuwait University and 2Mubarak Al Kabir Hospital, Kuwait
Objective: Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF)-
based systems are replacing biochemical systems for routine identification (ID) of bacteria, hence we
evaluated two MALDI-TOF MS and API AN systems for ID of clinical anaerobic pathogens.
Methods: A selection of 274 clinical isolates representing 4 genera and 14 species, obtained during a 7-
month of routine laboratory processing of clinical specimens, were subjected to ID by the bioMerieux
VITEK MSTM (VMS) and Bruker MICROFLEX MSTM (MMS) in parallel with conventional phenotypic
API 20 AN (CPA) method. For VMS and MMS, isolates were tested in duplicates as single deposits of
the same sets of isolates directly on MALDI-plate and for the API 20 AN, routine protocol was followed.
ID interpretation was according to manufacturer’s protocols; species were separated by a threshold of
50% matching peaks for VMS and ≥1.7=no reliable ID, 1.7-≤2.0=ID at genus level and ≥2.0=ID at
species level for MMS. Discrepant results were resolved by 16S rRNA gene sequencing.
Results: VMS and MMS correctly ID all isolates to genus level. All systems correctly ID all species of
the Porphyronomas, Prevotella, Clostridium and Peptostreptococcus. bioMerieux VMS and API were
in agreement in the ID of all (100%) Bacteroides spp., including all B. fragilis and B.
thetaiotaomicron isolates, two of which Bruker MMS misidentified as Malika spinosa and
Propionibacterium acne. The 2 discrepant results were resolved by 16S rRNA sequencing in favor of
VMS and API AN. In addition, log scores of 8 isolates (2 B. thetaiotaomicron, 1 B. fragilis, 1 P.
bivia, 1 B. ovatus, 1 B. vulgatus , 1 C. difficile , 1 C. sporogenes and 1 P. assacharolyticus were
<1.7 in the Bruker MMS, i.e. unreliable ID. Likewise, another 24 scored 1.7-<2.0, meaning they
could be validated only to genus level.
Conclusion: Both automated systems performed excellently well in terms of providing accurate ID 48-
72h earlier than the CPA method although VMS performed better in terms of identification of anaerobes
encountered in clinical specimens to species level in our hospital. In terms of user-friendliness,
bioMerieux VMS was better than Bruker MMS but both can be easily incorporated into routine diagnostic
procedures.