On the one hand, the presence of of P. jirovecii with mutations in the DHPS gene could be associated with sulfa drug use in the treatment or prophylaxis of PcP, but on the other hand, the increased widespread use of TMP-SMX for other infections could induce the appearance of mutations and P. jirovecii containing DHPS mutations can then subsequently be transmitted. The gene discussed is DHPS; the disease is infection.