An outbreak investigation finds identical bacterial strains from patient hand swabs and multiple shared workstation keyboards, but air sampling is negative for the organism. From an analytic standpoint, which mode of transmission is most likely driving the outbreak and which intervention should be prioritized?

• A. Airborne transmission is most likely despite negative air samples; prioritize long-range ventilation upgrades and ignore surface cleaning because environmental sampling never detects airborne organisms accurately.
• B. Transmission is impossible to determine from these data, so no intervention should be implemented until all possible reservoirs (human, animal, environmental) are eradicated by mass antibiotic distribution.
• C. Fomite transmission is most likely (contaminated keyboards serving as reservoirs); prioritize rigorous hand hygiene, surface disinfection, and removal of shared keyboards or installation of disposable covers to interrupt the fomite pathway.
• D. Vector-borne transmission must be the cause; release of insect predators will eliminate the vectors and therefore solve the contamination at keyboards.

Answer: (C)