What type of bacteria is known to cause sexually transmitted infections?

Chlamydia is recognized as a significant cause of sexually transmitted infections (STIs), particularly among young adults and adolescents. This bacterium, Chlamydia trachomatis, often does not produce noticeable symptoms, making it prevalent and easily spread. Untreated infections can lead to serious health issues, including pelvic inflammatory disease, infertility, and increased susceptibility to HIV.

The other bacteria listed, while they can cause various infections, are primarily associated with different health issues rather than being known as STIs. For example, Escherichia coli is mostly linked to gastrointestinal infections, Streptococcus can cause respiratory tract infections and other ailments, and Salmonella is primarily known for foodborne illnesses. Thus, Chlamydia stands out among the options as the primary bacterium associated with sexually transmitted infections.