Other Infections (non viral)
Candida albicans (formerly called Monilia) is a yeast, frequently present in small numbers in the healthy bowel and mouth. It may cause primary infection in the newborn or supeninfection when flora are disturbed by antibiotic treatment. In thrush (candidal stomatitis) white patches are seen in the mouth; it may occur in infants, in postoperative patients, and with ill-fitting dental plates. Vaginitis is common in pregnancy and diabetes. Candida may infect moist skin under breasts and the nailfolds, and cause severe intertnigo.
Administration of broad-spectrum antibiotics often results in proliferation of Candida in the respiratory tract and bowel, and may be responsible for digestive upsets. Systemic candidiasis with invasion of lung and bloodstream is a complication of immunosuppression in transplantation surgery, and in the chemotherapy of malignant disease. Oral thrush also occurs in AIDS.
Candidainfections are treated by the topical antibiotic nystatin or by gentian violet. Treatments for vaginal candidiasis include pessary treatment with clotrimazole (Canesten), miconazole nitrate (Gynodaktanin), econazole (Ecostatin) or tsoconazole nitrate (Travogyn) from 1 to 6 days or nystatin for 14 days. Ketoconazole 200 mg twice daily for 5 days and fluconazole 150 mg (single dose) are more recent oral treatments. In all cases of treatment failure, the male partner should be investigated for balanoposthitis, easily cured with clotnimazole or nystatin ointments locally.
Aspergillusspecies can cause a variety of clinical syndromes.
A type I hypersensitivity reaction.
Allergic broncho pulmonary aspergillosis
May be due to a type I and type III hypersensitivity reaction. Asthma and a chronic cough with sputum production occur and bronchiectasis may result.
A chronic infection in a previously damaged area of lung, e.g. an old tuberculous cavity, producing a characteristic radiographic appearance. Haemoptysis may result and surgical removal may be necessary.
Usually found in immunocompromised patients such as those undergoing chemotherapy for leukaemia. Treatment involves the use of amphotenicin B.
Chancroid (soft sore)
This infection is rare in Western countries. It is caused by the Gram-negative bacillus Ducrey (I-Iaemophilus ducreyi). Two to 5 days after infection, sores, often multiple, appear on the genitals. They become pustular and ulcerate, forming rounded, painful, soft, readily bleeding ulcers with undermined edges. Inguinal adenitis follows, the swollen nodes being hard and tender causing a feeling of stiffness in the groin. Resolution may occur at this stage, but suppuration may follow, the nodes becoming matted together forming a fluctuant unilocular abscess (hobo) with red overlying skin, in one or both groins. The bubo should never be incised since healing is very slow. Aspiration is correct. Phagedaena (a rapidly destructive ulceration) sometimes occurs.
Treatment. Any antibiotic which may prevent the identification of 717 pallidum in a case of concomitant syphilitic infection, or when the aetiology of the lesion is in doubt, is contraindicated. The mainstay of treatment has been co-trimoxazole 960 mg twice daily or erythromycin 500 mg four times daily for 1 week. However, resistance to cotrimoxazole is now appearing. Ciprofloxacin 500 mg twice daily for 3 days is an alternative. Regular daily cleaning of ulcers with isotonic saline is recommended.
This venereal disease is discussed in relation to the genitourinary system in Chapters 67 and 68.
Erysipelas is a spreading inflammation of the skin and subcutaneous tissues due to an infection by Streptococcus pyogenes (j3-haemolytic streptococcus Lancefield group A). Poor hygienic living conditions, recurrent upper respiratory tract infections, debilitating illness and extremes of life are predisposing causes, and the lesion develops around a scratch or abrasion which is the site of inoculation of the streptococcus. A rapid toxaemia associated with the local infection and a rose-pink rash extending over the adjacent skin rapidly develops. The rash has a very clear edge and considerable oedema occurs over some tissues when infected, e.g. orbit or scrotum. Following the fading of the rash, a brown discoloration of the skin remains. The S. pyogenes remains fully sensitive to penicillin (see also ‘Antimicrobial chemotherapy’)
Bacillus anthracis is a large, Gram-positive, aerobic, spore-forming rod. It is very resistant to heat and antiseptics. The disease is found in cattle and is likely to appear in people who handle carcasses, wool, hides, hair and bone meal.
The cutaneous type is the commonest human variety; the incubation period is from 3 to 4 days. The lesion usually commences on an exposed portion of the body, such as the hands, forearms or face. An itching papule occurs, around which a patch of induration soon becomes evident. The papule suppurates and is replaced by a black slough, and a ring of vesicles appears on the surrounding indurated area. This stage comprises the typical ‘malignant pustule’. A brawny, congested area of induration develops around the site of infection. The regional lymph nodes are involved. Toxaemia is always in evidence. A smear of vesicle fluid is used to confirm the diagnosis by culture and animal inoculation.
Treatment. Penicillin is the treatment of choice.
Prevention. This must include precautiOns to sterilise potentially infected animal products and wool from countries where the disease is endemic. A vaccine is available for those at special risk of exposure.
Differential diagnosis. The condition is easily mistaken for a severe furuncle.
Other forms of anthrax are rarely, if ever, now seen, e.g. wool-sorter’s disease, a pneumonia due to inhalation of spores, and an alimentary type, following ingestion of spores.
This disease is caused by Actinomyces israelli, an anaerobic, Gram-positive, branching, filamentous organism which sometimes lives as a harmless parasite in the tonsillar crypts and dental cavities of the otherwise normal mouth. It is popularly supposed that it occurs in corn and grasses, but the pathogenic bacillus does not. If the organism invades tissue, it causes a subacute pyogenic inflammation with considerable induration and sinus formation. Trauma and the presence of carious teeth are important predisposing factors in the development of lesions in the mouth.
Diagnosis depends on finding the organism in pus or in tissue section. Pus should be collected in a sterile tube (a swab is usually insufficient) and inspected in a good light for the presence of pinhead-sized ‘sulphur granules’. On microscopy, the granules are seen to consist of Gram-positive branching bacilli. The peripheral filaments radiate4 from the central part of the granule and may be surrounded by Gram-negative tissue clubs.
Culture. The presence of secondary organisms often makes this difficult.
The lesions are characterised by the formation of a firm, indurated mass, the edges of which are indefinite. Lymph nodes are not affected, but if a vein is invaded, pyaemia is likely.
There are four main clinical forms of actinomycosis.
• Faciocervical is the commonest. The lower jaw is more frequently affected, often adjacent to a carious tooth. The gum becomes so indurated that it simulates a bony swelling. Nodules appear, which soften and burst; the overlying skin of the face and neck becomes indurated and bluish in colour, softening occurs in patches. Abscesses burst through the skin and sinuses follow.
• Thorax. The lungs and pleura are infected, either by aspiration of the bacillus or by direct spread from the pharynx or neck, or even upwards through the diaphragm. The chest wall, in the late stages, becomes riddled with sinuses. An empyema is not uncommon, and the infection can easily spread through the diaphragm to the liver and the subphrenic spaces.
• Right iliac fossa .
Treatment. Actinomyces is usually sensitive to penicillin, ret racycline and some other antibiotics, e.g. lincomycin, but the sensitivity should be checked in the laboratory. A prolonged intensive course of penicillin (10 megaunits reducing to 4 megaunits daily) is usually the best treatment until all signs of the disease have disappeared.
Madura foot (and hand).
• Hydatid disease.
• Dracunculus medinensis.
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