Name two rapid diagnostic approaches used for bloodstream infections.

• A. MALDI-TOF MS for rapid organism identification; multiplex PCR-based panels (e.g., BioFire FilmArray BCID) for ID and some resistance markers.
• B. Disk diffusion; broth microdilution.
• C. Gram stain and culture.
• D. Serology and culture.

Answer: (A)

Rapid diagnosis of bloodstream infections hinges on fast, accurate organism identification and, when possible, resistance information. MALDI-TOF mass spectrometry identifies microbes by their protein fingerprint, delivering species-level IDs within minutes to hours after a culture becomes positive or directly from a positive blood culture bottle. This dramatically reduces the time to knowing exactly what is causing the infection. Multiplex PCR-based panels, such as BioFire FilmArray BCID, test many pathogens at once and can also detect certain resistance genes directly from positive blood cultures. They provide rapid results, typically within about one to two hours, giving both the culprit and some resistance information to guide therapy and infection control.

Other methods tend to be slower or provide less comprehensive rapid information. Disk diffusion and broth microdilution require growth of isolates to determine susceptibility, taking many hours to days. Gram stain and culture can offer quick initial clues but do not by themselves supply rapid, broad-range identification or resistance data. Serology and culture alone are often slower and less reliable for acute bloodstream infections.