A group of chemically related synthetic ANTIBIOTICS. Examples include nalidixic acid, cinoxacin and nor?oxocin which are e?ective in treating uncomplicated urinary-tract, respiratory-tract and gastrointestinal infections. They are usually e?ective against gram-negative and gram-positive bacteria (see GRAM’S STAIN). Many staphylococci – including METHICILLINRESISTANT STAPHYLOCOCCUS AUREUS (MRSA) – are resistant to quinolones. This group of drugs has a range of potentially troublesome side-effects including nausea, vomiting, DYSPEPSIA, abdominal pain, diarrhoea, dizziness, sleep disorders and PRURITUS.
Enteric fever is caused by bacterial infection with either Salmonella typhi or Salmonella paratyphi A, B or C. These infections are called typhoid fever, or paratyphoid fever respectively. Transmission usually occurs by ingestion of water or food that has been contaminated with human faeces – for example, by drinking water contaminated with sewage, or eating foods prepared by a cook infected with or carrying the organisms. Enteric fever is ENDEMIC in many areas of the world, including Africa, Central and South America, the Indian subcontinent and south-east Asia. Infection occasionally occurs in southern and eastern Europe, particularly with S. paratyphi B. However, in northern and western Europe and North America, most cases are imported.
Clinical course The incubation period of enteric fever is 7–21 days. Early symptoms include headache, malaise, dry cough, constipation and a slowly rising fever. Despite the fever, the patient’s pulse rate is often slow and he or she may have an enlarged SPLEEN. In the second week of illness, organisms invade the bloodstream again and symptoms progress. In general, symptoms of typhoid fever are more severe than those of paratyphoid fever: increasing mental slowness and confusion are common, and a more sustained high fever is present. In some individuals, discrete red spots appear on the upper trunk (rose spots). By the third week of illness the patient may become severely toxic, with marked confusion and delirium, abdominal distension, MYOCARDITIS, and occasionally intestinal haemorrage and/or perforation. Such complications may be fatal, although they are unusual if prompt treatment is given. Symptoms improve slowly into the fourth and ?fth weeks, although relapse may occur.
Diagnosis Enteric fever should be considered in any traveller or resident in an ENDEMIC area presenting with a febrile illness. The most common di?erential diagnosis is MALARIA. Diagnosis is usually made by isolation of the organism from cultures of blood in the ?rst two weeks of illness. Later the organisms are found in the stools and urine. Serological tests for ANTIBODIES against Salmonella typhi antigens (see ANTIGEN) (the Widal test) are less useful due to cross-reactions with antigens on other bacteria, and diffculties with interpretation in individuals immunised with typhoid vaccines.
Treatment Where facilities are available, hospital admission is required. Antibiotic therapy with chloramphenicol or amoxyacillin is e?ective. However, the potential toxicity of the former and the widespread resistance that has developed to both these antibiotics has led to the use of QUINOLONES such as CIPROFLOXACIN as the initial therapy for enteric fever in the UK and in areas where resistant organisms are common. A few individuals become chronic carriers of the organisms after they have recovered from the symptoms. These people are a potential source of spread to others and should be excluded from occupations that involve handling food or drinking-water.
Prolonged courses of antibiotic therapy may be required to eradicate carriage.
Prevention Worldwide, the most important preventive measure is improvement of sanitation and maintenance of clean water supplies. Vaccination is available for travellers to endemic areas.... enteric fever
n. one of a group of chemically related synthetic antibiotics that includes *ciprofloxacin, *nalidixic acid, and *ofloxacin. These drugs act by inactivating an enzyme, DNA gyrase, that is necessary for replication of the microorganisms and are often useful for treating infections with organisms that have become resistant to other antibiotics. Possible side-effects of quinolones include nausea, vomiting, diarrhoea, abdominal pain, headache, dizziness, and itching. Confusion, joint pains, skin troubles, and tendinitis occasionally occur.... quinolone
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