The Health Implications & Clinical Manifestations Of Pseudomembranous Colitis, Bartonellosis And Legionella Infections

Also known as antibiotic associated diarrhea, in this situation, diarrhea occurs as a common side effect of therapy with many antibiotics. In many cases, symptoms subside on withdrawal of the drug. Pseudomemebranous colitis develops following the use of clindamycin given for anaerobic sepsis, but it has been found to follow therapy with ampicillin or cephalosporins. Pathologically, the lesions consist of disruption of villous tips, infiltration by neutrophils and the presence of yellow plaque-like lesions on the mucosa, especially in the colon. These are caused by the toxins derived from Clostridium difficile which overgrows to become pathogenic. The organisms can be isolated and the toxin can be demonstrated in the feces by suitable methods. It is clinically characterized by abdominal pain, fever, leucocytosis and watery diarrhea. With the widespread use of antibiotics, pseudomembranous colitis has come into prominence. If not diagnosed and treated early, the mortality may go up to 50 to 60%.

Treatment: Clostridium difficile is susceptible to vancomycin, tetracycline and metronidazole, but vancomycin is the drug of choice since it is non-absorbable. It is given in a dose of 2g/day orally in four divided doses till diarrhea completely subsides. Early discontinuation of therapy may lead to relapse.

Also known as carrison;s disease or oroya fever or veruga Peruana, it is confined to the valleys of Andes mountains of South America and has not been reported in most parts of the world. It is caused by Bartonella bacilliformis, which is seen inside the erythrocytes. The disease is transmitted by the sandfly phlebotomus verrucarum. It presents different clinical pictures at different stages of evolution of the disease. After an incubation period of three weeks, the disease is characterized by two distinct clinical syndromes. The initial illness is characterized by constutituional symptoms like fever, rigors, nausea, diarrhea and headache. This is called Oroya fever and lasts for 3 to 4 weeks. Organisms can be demonstrated in blood smears stained by Giemsa’s or Wright’s stain. Death may occur at this stage due to severe anemia or superinfection by Salmonella.

The second stage, called Verruga peruana is characterized by hemangiomatous tumours of skin and mucous membranes varying in size between 2 to 15 mm, some of which may ulcerate. Mortality is very low at this stage, since immunity develops. Specific treatment is with chloramphenicol or tetracyclines in addition to supportive measures.

This disease, caused by Legionella pneumophilia, is being increasingly reported here in the west. The first description was given in 1976 following the outbreak of an unusual pneumonic illness among members attending the legion convention at Philadelphia. The organisms have been isolated from air conditioning systems, water taps, soil and other environment. It is acquired by inhalation, ingestion, or through the conjunctiva.

The incubation period is 2 to 10 days after which the patient presents with fever, anorexia, weight loss, headache, myalgia and confusion. Severe cases progress to pneumonia and pleurisy.

Diagnosis is made on serologic examination by demonstration of a four-fold increase in the antibodies against Legionella or by immune-fluorescence studies of the sputum, pleural fluid, or bronchial aspirates. Special techniques are required to grow the organisms. Legionella Pneumophilia responds to erythromycin and rifampicin if given early in the course of the disease. The disease carries a mortality ranging from 10 to 20%. Immuno-compromised subjects suffer more.