Identify the mismatched bacterium and specimen pairing.

The correct identification of the mismatched bacterium and specimen pairing hinges on understanding the specific clinical contexts and typical specimens used for diagnosing the listed pathogens.

Chlamydia (Chlamydophila) psittaci is primarily associated with respiratory infections, particularly psittacosis, which is often transmitted via inhalation of contaminated materials related to birds. The appropriate specimens for diagnosing C. psittaci infections typically include respiratory specimens such as sputum or throat swabs, rather than fecal swabs. Fecal swabs are not the standard for diagnosing this organism, making this pairing incorrect.

In contrast, Chlamydia trachomatis, which causes sexually transmitted infections, is correctly matched with first voided urine and endocervical swabs as appropriate specimens. First voided urine is particularly useful for non-invasive testing in urinary tract infections caused by this bacterium, while endocervical swabs are standard for more direct assessment of infections in sexually active females.

Chlamydia pneumoniae is associated with respiratory illnesses and can indeed be detected using throat swabs or sputum, reinforcing that this pairing is correctly matched. Thus, the only incorrect or misleading pairing in the choices presented is Chlamydia (Chlamydophila)