Subtyping Keyvisual

Bacteroides fragilis cfiA Subtyping

B. fragilis is the most frequently isolated anaerobic pathogen. It is part of the intestinal flora and generally commensal, but can cause infection if displaced into the bloodstream or surrounding tissue following surgery, disease, or trauma. Infections with B. fragilis can cause severe symptoms including abscess formation and sepsis.

B. fragilis and carbapenem resistance

Carbapenem resistance in B. fragilis is frequently associated with presence of the cfiA gene, encoding a metallo-beta-lactamase conferring resistance to nearly all beta-lactam antibiotics. As a result infections with B. fragilis cfiA positive strains are very difficult to treat. Different studies show the increase in the resistance to carbapenems of B. fragilis and also the increased frequency to harbour the cfiA gene silently.

Automated detection of cfiA positive strains

Prerequisite for initiation of the cfiA detection process is successful identification of B. fragilis in the MBT identification workflow. The MBT Subtyping Module looks then automatically for specific peaks associated with the protein expressed by B. fragilis cfiA positive strains. If present, the best match for the respective sample will be reported as a presumptive cfiA positive strain.





Not for use in clinical diagnostic procedures.

B. fragilis

Identification results for B. fragilis with indication of cfiA status for the best match

An early warning system

Reporting of cfiA negative results does not mean that the bacterium is susceptible, because other resistance mechanisms could be present. Therefore additional confirmation methods are required if cfiA is not detected by the MBT Subtyping Module.

The MBT Subtyping Module also detects blaKPC expressing Klebsiella pneumoniae  and PSM-mec carrying Staphylococcus aureus strains.