The human pathogens in terms of pH are meant as acidophiles which are acid-loving organisms and basophils the base(alkaline condition) loving organism. The lowest pH is the minimum growth pH and the highest growth pH is maximum growth pH.
The optimum acidic pH is considered as 5.5 for acidophiles. The stomach acid is the condition where the Ecoli, S typhi, and other intestinal pathogens are much resistant to stomach acid.
The hyperthermophile is an organism that can easily survive in an extremely hot environment. They can thrive in extreme temperature, the bacteria and Archea species can tolerate up to 100-degree Celcius. They can easily exist in high acidic and high radiation conditions.
Most familiar bacteria, like Escherichia coli, staphylococci, and Salmonella spp. are neutrophiles.
They thrive better in neutral condition and also they are meant to be surviving and having restrictions even in the alkaline environment.
Hence the human pathogens like Ecoli and S typhi belong to neutrophiles.
The below picture the profile of the pathogens growing in various condition:
acidophile neutrophile alkaliphile Growth rate 0 1 2 3 4 5 6 7 8 9 10 11 12 PH