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, and Neisseria gonorrhoeae were 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 and Enterococcus). Sensitivity was increased to 10−2 bacteria/mL for GBS, 10−1 bacteria/mL for E. faecalis, and 101 bacteria/mL for N. gonorrhoeae following 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.

Antimicrobial susceptibility testing: currently used methods and devices and the near future in clinical practice

“…In the case of routine methods for AST, it usually takes at least 24 h to obtain growth of bacterial colonies and an additional 24 h to obtain isolate characterization, namely biochemical identification and phenotypic AST (Altaie and Dryja 1994;Faro et al 2016). The methods generally used afford qualitative results, using the susceptible, intermediate or resistant categories, but some of them provide quantitative results, expressed as minimum inhibitory concentration (MIC) (Jenkins and Schuetz 2012).…”

Narrow-spectrum antibacterial agents

“…26 Culture methods take long periods of time, initial cultures take 24–48 h (during which time broad-spectrum antibiotics are typically initiated), then following identification of the microbe, antimicrobial susceptibility determination requires another 24–48 h. 27 In a 2015 survey of infectious disease practitioners, 31% reported that they believed patients are treated with incorrect antibiotics during the wait for blood culture results. 28 In addition to long-turnaround times, culture-based methods also have the potential to return false-negative results when samples are obtained after antimicrobial therapy has begun.…”