Bacterial Test Is Well-Suited for Mid-Sized Labs

Early diagnosis and the institution of appropriate antimicrobial therapy are vital for favorable patient outcomes.

Traditional culture and antimicrobial susceptibility test methods are time dependent processes that often require two to four days before final test results are available. A recently developed assay is an accurate and reliable tool for the detection of the five most common gram-positive bacteria responsible for bloodstream infections.

A team of medical laboratory scientist from different institutions and led by the Laboratory Alliance of Central New York (Syracuse, NY, USA) collected and tested 1,134 patient blood culture clinical specimens from January 2015 until October 2016. Three different automated blood culture systems were evaluated: BacT/ALERT; BACTEC and VersaTREK. These were compared with the iC-GPC assay.

The iC-GPC gram-positive assay is a qualitative, multiplex test for the direct detection from positive blood cultures of five of the most common gram-positive bacteria responsible for bacterial bloodstream infections: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Enterococcus faecalis, and Enterococcus faecium. In the multicenter trial, involving testing on patient blood culture specimens that were positive for gram-positive cocci, the assay also detected the presence of mecA, vanA, and vanB resistance determinants.

The iC-GPC Assay had an overall percent agreement with the BC-GP assay of 95.5%. Discordant specimens were further analyzed by a polymerase chain reaction (PCR) and bidirectional sequencing method. The results indicate that the iC-GPC Assay together with the iCubate System is an accurate and reliable tool for the detection of the five most common gram-positive bacteria and their resistance markers responsible for bloodstream infections.

The authors concluded that the iC-GPC Assay provides a significantly more affordable alternative, particularly for small to medium-sized health care institutions, for the molecular detection of common gram-positive bacteria responsible for bloodstream infections and their resistance markers.

Paul A. Granato, PhD, Director of Microbiology and lead author of the study, said, “Traditional methods for the diagnosis or detection of what is causing bloodstream infections, such as septicemia, take two to five days to identify the bacterium and determine what type of antibiotic would be most appropriate for the treatment of a patient.” The study was originally published online on June 13, 2018, in the Journal of Clinical Microbiology.

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Laboratory Alliance of Central New York