This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
An increased frequency of infections due to which of the following organism has been repoed among patients with achlorhydria? 
Select and explain. 
A. Salmonella, B. Shigella, C. Entamoeba, D. Vibrio cholera
A: Salmonella
Answer: A: Salmonella 
Explanation: The acidic pH of the stomach is an impoant barrier to some enteric pathogens. An increased frequency of infections due to Salmonella, G. lamblia, is seen in patients who have undergone gastric surgery or are achlorhydric for some other reason. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page1085