The newest flora of your pharynx and trachea are normally taken for each other ?- and you will ?-haemolytic streptococci also a number of anaerobes, staphylococci (plus Staph. aureus), Neisseria and you can diphtheroids. The brand new respiratory system is sometimes somewhat sterile, in spite of the regular intake regarding organisms by respiration. Although not, good variety of clinically regular anybody can get carry the brand new fungus Pneumocystis jirovecii (prior to now also known as P. carinii) within their lungs.

The stomach normally harbours only transient organisms, its acidic pH providing an effective barrier. However, the gastric mucosa may be colonized by acid-tolerant lactobacilli and streptococci. Helicobacter pylori, which can cause gastric ulcers (see Ch. twenty two), is carried without symptoms by large numbers of people, the bacterium being in mucus and neutralizing the local acidic environment. The upper intestine is only lightly colonized (10 4 organisms/g), but populations increase markedly in the ileum, where streptococci, lactobacilli, enterobacteriaceae and Bacteroides may all be present. Continue reading →