Is it common to get pseudomonas aeruginosa after a thoracoscopy?

Not very common. But postoperative infections can happen after any surgery.
Infection or coloniz. No, it is uncommon to have pseudomonas in the respiratory tract if you are a non-hospitalized, otherwise normal individual. If you have some immune deficiency, or if the thorascopy was not done with sterile instruments, it is possible, but still unlikely.