Development of a Novel Test for Simultaneous Bacterial Identification and Antibiotic Susceptibility

Abstract

Background. Elucidation of a pathogen’s antimicrobial susceptibility requires subculture after the organism is first isolated. This takes several days, requiring patients to be treated with broad-spectrum antibiotics. This approach contributes to the development of bacterial resistance.Methods. Microtiter wells were coated with a polyclonal antibody targeting the pathogen of interest. Bacterial suspensions were added in the presence/absence of selected antibiotics. After washing, captured bacteria were detected.Findings. Group B streptococcus (GBS),Enterococcus faecalis, andNeisseria gonorrhoeaewere each detected at 105 bacteria/mL following a 20-minute incubation period. Susceptibility to select antibiotics was discernable following a 6-hour incubation period (GBS andEnterococcus). Sensitivity was increased to 10−2 bacteria/mL for GBS, 10−1 bacteria/mL forE. faecalis, and 101 bacteria/mL forN. gonorrhoeaefollowing 18–24-hour culture.Conclusion. This novel assay allows for the highly sensitive and specific identification of a pathogen and simultaneous determination of its antimicrobial susceptibility in a reduced time.