Which of the following Enterobacteriaceae is known for causing urinary tract infections?

• A. Salmonella
• B. Shigella
• C. Escherichia coli
• D. Proteus

Answer: (C)

Escherichia coli is widely recognized as the predominant cause of urinary tract infections (UTIs). This bacterium is part of the normal gut flora but can lead to infections when it translocates to the urinary tract. Specific strains, particularly uropathogenic E. coli (UPEC), are equipped with virulence factors such as fimbriae, which facilitate adherence to the uroepithelial cells, allowing the bacteria to overcome the flushing action of urine.

This pathogenic ability not only enables E. coli to colonize the urinary tract but also makes it capable of evading the immune response, thereby fostering an environment conducive to infection. The prevalence of E. coli in UTI cases underscores its role as a primary etiological agent in such infections.

In contrast, while Salmonella and Shigella are both members of the Enterobacteriaceae family, they are primarily associated with gastrointestinal diseases rather than UTIs. Salmonella is known for causing gastroenteritis and typhoid fever, while Shigella typically leads to dysentery. Proteus, another member of the Enterobacteriaceae, can also cause UTIs and is notable for producing urease, which can contribute to struvite stone formation, but it is less