Surgeries
Surgeries do not directly cause pneumonia but it significantly increases your risk of getting infected. [12] Medicines like anesthesia are administered before going under the knife to induce unconsciousness. However, if there’s food in your stomach during the time of administering anesthetics, it may cause fluids or vomits to get back into the lungs, causing aspiration pneumonia.
There is also the risk of getting infected right after surgery usually caused by polymicrobial bacteria. Patients who have a high risk for aspiration are susceptible to aerobic bacteria including pseudomonas, klebsiella, and enterobacter. Research conducted in 2017 showed that postoperative pneumonia is the third most common complication for all surgical procedures and has a high mortality rate. [13]
Reference:
[1] https://www.cdc.gov/fungal/pdf/cocci-fact-sheet-sw-us-508c.pdf
[2] https://www.webmd.com/lung/bacterial-pneumonia#:~:text=Bacterial%20pneumonia%20is%20an%20infection,throat%20without%20causing%20any%20trouble.
[3] https://www.webmd.com/lung/viral-pneumonia
[4] https://www.medicinenet.com/pneumonia_facts/article.htm
[5] https://www.medicalnewstoday.com/articles/322091
[6] https://www.webmd.com/lung/understanding-pneumonia-basics
[7]https://www.webmd.com/cancer/lymphoma/understanding-leukemia-basics
[8]https://www.webmd.com/cancer/lymphoma/lymphoma-cancer
[9]https://medlineplus.gov/ency/article/000091.htm
[10]https://medlineplus.gov/ency/article/000144.htm
[11] https://www.webmd.com/lung/viral-pneumonia
[12] https://www.webmd.com/lung/pneumonia-reducing-your-risk
[13] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5412519/