What atmospheric condition is required to recover Campylobacter species from selective agar?

Campylobacter species are microaerophilic bacteria, meaning they thrive in environments with reduced oxygen levels compared to atmospheric air. The ideal atmospheric condition for the recovery of Campylobacter from selective agar is specifically characterized by lower oxygen content, moderate carbon dioxide, and a balanced nitrogen composition.

The formulation of 5% O2, 10% CO2, and 85% N2 creates an environment that closely mimics the natural habitats of these bacteria. Under such conditions, the low oxygen levels support the growth of Campylobacter while the elevated CO2 levels help to ensure proper metabolism and growth conditions. The high proportion of nitrogen serves to maintain a stable, anaerobic-like environment, which is essential for Campylobacter's growth.

The other atmospheric conditions listed in the choices do not provide the requisite low oxygen levels or the appropriate balance of gases to support Campylobacter growth. For instance, the presence of 20% O2 in other options would be too high for Campylobacter, which cannot tolerate high oxygen concentrations and would thus hinder their recovery from selective agar.