We live in a world heavily populated by microorganisms of astonishing diversity. Most of these exist in our external environment but certain classes are normally harboured within our bodies, especially colonising mucosal surfaces. Depending on the circumstances, infectious disease can arise from organisms living exogenously or endogenously, and a knowledge of common pathogens at specific sites often provides a good basis for rational initial therapy.

This chapter considers the bacteria that cause disease in individual body systems, the drugs that are used to combat them, and how they are best used. It discusses infection of:

• Paransal sinuses and ears

• Bronchi, lungs and pleura

• Endocardium

• Intestines

• Urinary tract

• Genital tract

• Bones and joints

• Also mycobacteria, that infect many sites

Table 11.1 (p. 21 I) is a general reference for this chapter.

Infection of the blood

Septicaemia is a medical emergency. Accurate microbiological diagnosis is of the first importance and blood cultures should be taken before starting antimicrobial therapy. Usually, the infecting organism^) is not known at the time of presentation and treatment must be instituted on the basis of a 'best guess'. The clinical circumstances may provide some clues. Patients who have been in hospital for some time before presenting with septicaemia may need antibiotic regimens that provide more reliable cover for multiply resistant pathogens, and examples of suitable choices are given in the list below in brackets.

• When septicaemia follows gastrointestinal or genital tract surgery, Escherichia coli (or other Gram-negative bacteria), anaerobic bacteria, e.g. Bacteroides, streptococci or enterococci are likely pathogens and the following combinations are effective: cefuroxime plus metronidazole or gentamicin plus benzylpenicillin plus metronidazole (meropenem plus vancomycin).

• Septicaemia related to urinary tract infection usually involves Escherichia coli (or other Gramnegative bacteria), enterococci: gentamicin plus benzylpenicillin or cefotaxime alone (ciprofloxacin plus vancomycin).

• Neonatal septicaemia is usually due to streptococci or coliforms: benzylpenicillin plus gentamicin.

• Staphylococcal septicaemia may be suspected where there is an abscess, e.g. of bone or lung, or with acute infective endocarditis or infection of intravenous catheters: high dose flucloxacillin is indicated (vancomycin).

• Toxic shock syndrome occurs in circumstances that include healthy women using vaginal tampons, abortion or childbirth, and occasionally with skin and soft tissue infection. The clinical problem is due to systemic effects of toxins produced by staphylococci: while this is not strictly an infection of the blood, flucloxacillin is used to eliminate the source. Elimination of the source by removal of the tampon and drainage of abscesses, and circulatory support are also important.

Antimicrobials should be given i.v. initially in septicaemia.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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