**16. Conclusion**

Infective endocarditis caused by NVS has posed tremendous diagnostic and therapeutic challenges and continue to do so even in the era of modern medicine. Delays in diagnosis due to difficulties in identification frequently cause delays in treatment and poor treatment outcomes. Treatment failure and high complication rates associated with *Abiotrophia* and *Granulicatella* endocarditis is at least partially attributable to the pleomorphic nature of the organisms, lack of growth in subcultures and specific nutritional requirements in media along with the need for the microbiology lab staff to have heightened awareness of these microorganisms. Their fastidious nature of NVS makes the antibiotic susceptibility testing fairly difficult, causing delays in initiation of timely and effective antibiotic treatment.

Interpretation of the medical literature of *Abiotrophia* and *Granulicatella* spp. and its application to current clinical practice is challenging as the names of these organisms have been changed several times and not uncommonly the two genera were addressed together. There is lack of large clinical studies and our knowledge about these organisms is based on relatively small number of reported cases.

Differences in pathogenicity and susceptibility to antimicrobials have been demonstrated among these heterogeneous group of bacteria. More studies are needed to determine if there are further species specific differences of these fascinating microorganisms which would help us improve our understanding, diagnosis and the treatment outcomes of infections caused by NVS.
