Infective endocarditis complicating psittacosis: response to rifampicin

Chlamydia psittaci endocarditis: a case report and literature review

OBJECTIVES

Blood-culture-negative infective endocarditis (BCNE) is found in 2 to 48% of cases of infective endocarditis (IE) [1].IE and vertebral osteomyelitis due to Chlamydia sp. are difficult to diagnose.

PATIENTS AND METHODS

A case report of Chlamydia psittaci IE is provided, associated with a literature review.

RESULTS

We report the first case of Chlamydia psittaci IE, revealed by a spondylodiscitis. Questioning of the patient, imaging, serologies and PCR techniques on valves confirmed the diagnosis.

CONCLUSION

C. psittaci IE is rare but probably underdiagnosed. In case of negative blood cultures, questioning patients with IE about their contacts with animals is relevant. PCR techniques are reference tools for diagnosis confirmation when valve or vertebral samples are available.

Endocarditis due to rare and fastidious bacteria

The etiologic diagnosis of infective endocarditis is easily made in the presence of continuous bacteremia with gram-positive cocci. However, the blood culture may contain a bacterium rarely associated with endocarditis, such as Lactobacillus spp., Klebsiella spp., or nontoxigenic Corynebacterium, Salmonella, Gemella, Campylobacter, Aeromonas, Yersinia, Nocardia, Pasteurella, Listeria, or Erysipelothrix spp., that requires further investigation to establish the relationship with endocarditis, or the blood culture may be uninformative despite a supportive clinical evaluation. In the latter case, the etiologic agents are either fastidious extracellular or intracellular bacteria. Fastidious extracellular bacteria such as Abiotrophia, HACEK group bacteria, Clostridium, Brucella, Legionella, Mycobacterium, and Bartonella spp. need supplemented media, prolonged incubation time, and special culture conditions. Intracellular bacteria such as Coxiella burnetii cannot be isolated routinely. The two most prevalent etiologic agents of culture-negative endocarditis are C. burnetti and Bartonella spp. Their diagnosis is usually carried out serologically. A systemic pathologic examination of excised heart valves including periodic acid-Schiff (PAS) staining and molecular methods has allowed the identification of Whipple's bacillus endocarditis. Pathologic examination of the valve using special staining, such as Warthin-Starry, Gimenez, and PAS, and broad-spectrum PCR should be performed systematically when no etiologic diagnosis is evident through routine laboratory evaluation.

Effect of azithromycin plus rifampin versus that of azithromycin alone on the eradication of Chlamydia pneumoniae from lung tissue in experimental pneumonitis

Azithromycin, doxycycline, and rifampin, alone or in combination, were tested in vitro against Chlamydia pneumoniae AR-39. The combination of azithromycin plus rifampin showed the strongest activity and produced higher rates of eradication of C. pneumoniae from lung tissues than azithromycin alone in experimental mouse pneumonitis.

Serological cross-reactions between Bartonella and Chlamydia species: implications for diagnosis

Diagnosis of Chlamydia or Bartonella infections continues to rely mainly on serology. However, serological cross-reactions between members of these genera have recently been described. Sera from eight patients originally diagnosed as having Chlamydia pneumoniae endocarditis reacted with both Chlamydia sp. and Bartonella quintana antigens (microimmunofluorescence technique). Adsorption of sera with B. quintana or C. pneumoniae antigens removed anti-C. pneumoniae antibodies, whereas adsorption with C. pneumoniae antigens did not change antibody titers to B. quintana. Western blot analysis confirmed the presence of cross-reacting antigens and showed antibody patterns in all sera to be compatible with a Bartonella infection. These patients were therefore probably suffering from Bartonella-induced rather than Chlamydia-induced endocarditis. In contrast, sera from 10 patients presumed to be suffering from C. pneumoniae pneumonia did not display anti-B. quintana antibodies, although cross-reacting antigens were revealed by Western blotting. This work highlights the possibility that cases of infective Bartonella endocarditis are erroneously diagnosed as chlamydial infections.

Use of rifampin in nonstaphylococcal, nonmycobacterial disease

Rifampin has very broad antimicrobial properties with in vitro activities against many bacteria, mycobacteria, higher bacteria, chlamydia, fungi, parasites, and viruses (Table 1). The clinical use of rifampin is more limited, in part because of the lack of in vivo human clinical studies demonstrating its efficacy. Investigators have valid concerns regarding the emergence of resistance of mycobacteria if widespread use of rifampin becomes common, although this has not been well documented. Because rifampin obtains therapeutic levels intracellularly and is distributed widely throughout the body, the antibiotic potentially could be used on a broader scale, but more studies will be needed to demonstrate its clinical utility.

Chlamydial infections of the heart

Chlamydiae are common human pathogens, causing a broad spectrum of infectious diseases. Chlamydial infections involving the heart have been described in numerous previous reports. These organisms are documented to cause endocarditis, myocarditis and pericarditis. Furthermore, Chlamydia pneumoniae, the recently discovered respiratory pathogen, has also been implicated in coronary artery disease. For the first time the literature on involvement of the heart in chlamydial infections is reviewed. Information on the discovery of Chlamydia species is also included and the problem of the species determination of Chlamydia in interpretation of the older literature is mentioned.

Coxiella burneti endocarditis in a patient with positive chlamydial serology

A 41-year-old man who habitually slept in a car park presented with a culture-negative endocarditis. Serological tests indicated infection with both Coxiella burneti and Chlamydia psittaci. He was treated with doxycycline and clindamycin and required aortic valve replacement. Culture of the excised value for both agents was negative but electron microscopy was suggestive of coxiella endocarditis.

A progressive pericardial effusion caused by psittacosis

A patient developed signs of a progressive pericardial effusion over a period of eight days. Diagnostic and therapeutic pericardiocentesis was performed. Viral titres to psittacosis rose from less than 1:8 to greater than 1:256 indicating recent infection.

Successful treatment by doxycycline of endocarditis caused by ornithosis

The case of a 59 year old man with ornithosis endocarditis and a history of contact with pheasants is reported. Treatment with oxytetracycline was not tolerated and so doxycycline was substituted. Over the two year follow up the patient's clinical condition and serial echocardiographic appearances improved and Chlamydia psittaci complement fixation titres returned to normal. Valve replacement was not required.

Psittacosis

Images

Chlamydial endocarditis

Echocardiographic diagnosis of a case of endocarditis, subsequently proven to be due to a chlamydial organism, is described. Early echocardiographic diagnosis guided initial medical management and directed urgent surgical intervention when the patient deteriorated. Reported cases of chlamydial endocarditis are reviewed.

"Prolonged pregnancy" after oral contraceptive therapy

A prospective study of 151 patients whose last menstrual period was an oral contraceptive induced haemorrhage indicated that, in many, ovulation was considerably delayed and that the calculated due date of delivery was therefore erroneous; prolonged pregnancy (more than 42 weeks gestation) occurred in 37.4% and, in 9%, gestation exceed 44 weeks.