The brand new plants of the pharynx and trachea start from both ?- and you can ?-haemolytic streptococci as well as a great amount of anaerobes, staphylococci (and additionally Staph. aureus), Neisseria and diphtheroids. The fresh new respiratory tract is sometimes a bit sterile, inspite of the normal intake away from organisms by respiration. Although not, big quantities of clinically typical individuals will get bring the latest fungi Pneumocystis jirovecii (in earlier times labeled as P. carinii) in their lung area.
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. 22), 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. Bacterial numbers are very high (estimated at 10 11 /g) in the large bowel, and many species can be found (Fig. 8.dos). The vast majority (95–99%) are anaerobes, Bacteroides being especially common and a major component of faecal material; E. Continue reading »
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