A slaughterhouse worker presented with fever and a pleuropericardial effusion. Conventional microbiology failed to identify the responsible organism. However, DNA sequencing definitively identified Campylobacter fetus ssp fetus, which is rare in immunocompetent individuals. Prolonged treatment was required to eradicate the infection.
- pyrexia of unknown origin
- Campylobacter fetus ssp fetus
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Patients may be exposed to various infective agents in their working environment and when travelling. Thus a full occupational and travel history should be sought, particularly in patients presenting with a febrile illness. In view of the wide spectrum of organisms involved, microbiological identification may be difficult and specialist help with new techniques such as DNA sequencing may be required.
A previously fit 54 year old male slaughterhouse worker presented with pleuritic chest pain following a week of lethargy and fever. He had no past medical problems and was not on any treatment. A detailed occupational history was elicited. His job involved hosing out animal carcasses. He had to rip out the neural tissue (spinal cord) using gloved hands. He admitted that accidental damage had occurred to a glove. There was no history of foreign travel. He was a non-smoker and drank very little alcohol.
Clinical examination on admission was unremarkable but he developed a swinging pyrexia of 38°C and a pericardial rub two days after admission. An ECG showed upwardly concave ST elevation in lead II and V4–V6 (fig 1), indicating pericarditis. An echocardiogram showed pericardial and pleural effusions (fig 2).
Routine haematology and biochemistry results were normal, apart from raised serum C reactive protein (156 mg/l). Blood culture grew a Gram negative spiral organism could not be identified by standard biochemical methods but was identified by DNA sequencing asCampylobacter fetus ssp fetus.
The patients was treated with amoxycillin, metronidazole, and tetracycline and the fever and effusions resolved after seven days of treatment. He was discharged with advice to continue treatment with tetracycline for a further three weeks.
Three weeks later, after stopping antimicrobials, he was readmitted with fever and breathlessness. Clinical examination and blood investigations were again unremarkable except for a raised C reactive protein concentration (211 mg/l). He was treated with ciprofloxacin 500 mg twice daily for one week. Symptoms resolved and he was discharged home taking oral ciprofloxacin for a further four weeks. At the end of this time he was reviewed in the clinic and was found to be well. Follow up at three months showed no recurrence of the infection.
Campylobacter fetus ssp fetusinfection is rare. It commonly presents with non-specific flu-like symptoms and bacteraemia.1 It should be considered in the differential diagnosis of pyrexia of unknown origin. The organism is transmitted to humans through undercooked meat products or by direct contact with infected animals,2 as in this case. Relapsing fever may occur.1 2 Pericarditis caused by Campylobacter fetus ssp fetus is rarely described in people with normal immunity.1 In more than half the cases the bacteraemia is secondary to localised infections such as septic arthritis, pelvic inflammatory disease, meningitis, endocarditis, pneumonia, thrombophlebitis, or mycotic aneurysm.3 Blood cultures may take from 3 to 25 days to grow the organism. In this unusual case of relapsing fever, a long course of treatment with ciprofloxacin was necessary. Mortality in such cases ranges from 17% to 43%.1 Erythromycin and ciprofloxacin are the agents of choice for treatment.
The case also shows how a molecular approach can aid in the rapid identification of “difficult” bacterial isolates, using direct sequence analysis of the gene encoding the 16S RNA species of the ribosome.4 5 This bacterium's entire 16S gene was successfully amplified by polymerase chain reaction, sequenced, and compared with sequences on the database. It was unequivocally shown to share 100% identity with Campylobacter fetus ssp fetus (Genebank accession number M65012). This technique can be used in the diagnosis of organisms that are hard to identify by routine microbiological testing.
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