An 11-day-old neonate has been brought to his paediatrician because the infant has developed a sharp cough. Physical examination also reveals a mild conjunctivitis with some pus; a chest film confirms pneumonia. No organisms are seen on Gram stain of the pus. What is the most likely causative agent?
An obligate intracellular organism unable to make its own ATP A diplococcus that has a high potential to cause blindness as well as the pneumonia An organism that has no peptidoglycan or other cell-wall polymer An obligate intracellular organism infective vascular endothelium