Response of HIV-associated disseminated cat scratch disease to treatment with doxycycline

Efficacy of enrofloxacin or doxycycline for treatment of Bartonella henselae or Bartonella clarridgeiae infection in cats

Enrofloxacin and doxycycline are antimicrobial agents used to treat bacterial diseases of cats. In vitro susceptibility data indicate that either drug should be effective against Bartonella species. In vivo efficacies of these drugs for eradication of chronic Bartonella henselae or Bartonella clarridgeiae infections were examined in 18 experimentally infected cats and 25 naturally exposed cats treated with enrofloxacin (22.7 mg given orally [PO] every 12 h [q12h] [14 days, n = 10; 28 days, n = 13]) or with doxycycline (25 mg PO q12h [14 days, n = 9; 28 days, n = 8]) or not treated (n = 3). Plasma drug concentrations were determined in experimental cats by high-performance liquid chromatography. Only 23 of 43 cats enrolled ultimately met inclusion criteria. Bacteremia was eliminated for 12 to 25 weeks posttreatment in four of seven cats receiving 14 days of enrofloxacin, five of seven cats receiving 28 days of enrofloxacin, one of six cats receiving 14 days of doxycycline, and one of two cats receiving 28 days of doxycycline. Defining a negative result by blood culture as treatment success may be erroneous; these results may reflect the insensitivity of blood culture or the relapsing nature of Bartonella bacteremia. Our results suggest that MICs obtained with axenic media do not predict antimicrobial activity against intracellular Bartonella, that a long treatment course is required to eliminate infection, and that duration of therapy correlates with pretreatment bacterial load. Given current concern about the development of antimicrobial resistance, we would reserve recommendation for treatment to cats owned by an immunocompromised individual or as an alternative to euthanasia of a pet.

Diagnosis and treatment of infectious diseases in HIV-infected hosts

Treatment of infectious diseases in patients with HIV infection is of primary importance in patient care. Viral, bacterial, parasitic, and fungal pathogens all may affect these patients. It is essential that accurate diagnoses be made and appropriate therapy be administered as early as possible.

Bartonella spp. as emerging human pathogens

Members of the genus Bartonella (formerly Rochalimaea) were virtually unknown to modern-day clinicians and microbiologists until they were associated with opportunistic infections in AIDS patients about 6 years ago. Since that time, Bartonella species have been associated with cat scratch disease, bacillary angiomatosis, and a variety of other disease syndromes. Clinical presentation of infection with Bartonella ranges from a relatively mild lymphadenopathy with few other symptoms, seen in cat scratch disease, to life-threatening systemic disease in the immunocompromised patient. In some individuals, infection manifests as lesions that exhibit proliferation of endothelial cells and neovascularization, a pathogenic process unique to this genus of bacteria. As the spectrum of disease attributed to Bartonella is further defined, the need for reliable laboratory methods to diagnose infections caused by these unique organisms also increases. A brief summary of the clinical presentations associated with Bartonella infections is presented, and the current status of laboratory diagnosis and identification of these organisms is reviewed.

Characterization of a 17-kilodalton antigen of Bartonella henselae reactive with sera from patients with cat scratch disease

A library of Bartonella (Rochalimaea) henselae DNA was constructed in the cloning vector lambda ZAPII and screened for expression of antigenic proteins by using a pool of sera from patients who had been diagnosed with cat scratch disease (CSD) and had antibodies to Bartonella spp., as determined by indirect fluorescent-antibody (IFA) assay. Ten immunoreactive phages were subcloned as recombinant plasmids by in vivo excision. All 10 recombinants expressed a protein of approximately 17 kDa when they were examined by immunoblot with the pool of human sera. Restriction endonuclease digestion of each recombinant plasmid indicated seven profiles, suggesting that cloning bias was not the reason for repeated isolation of clones expressing the 17-kDa antigen. The gene coding for the 17-kDa antigen was sequenced and shown to code for an open reading frame of 148 amino acids with a predicted molecular mass of 16,893 Da. The amino terminus of the deduced amino acid sequence was hydrophobic in nature and similar in size and composition to signal peptides found in gram-negative bacteria. The remainder of the deduced amino acid sequence was more hydrophilic and may represent surface-exposed epitopes. Further subcloning of the 17-kDa antigen as a biotinylated fusion protein in the expression vector PinPoint Xa-2 resulted in a 30-kDa protein that was highly reactive on immunoblots with individual serum samples from patients with CSD. The agreement between reactivity with the 30-kDa fusion protein on immunoblot analysis and the results obtained by IFA assay was 92% for IFA-positive sera and 88% for IFA-negative sera. The recombinant-expressed 17-kDa protein should be of value as an antigen for serologic diagnosis of CSD and Bartonella infections and warrants further study in attempts to develop a subunit vaccine to prevent long-term Bartonella infection in cats and the potential for further spread of these organisms to humans.

Histological and ultrastructural study of one case of oral bacillary angiomatosis in HIV disease and review of the literature

Bacillary angiomatosis (BA) is a new clinicopathological entity defined as a pseudo-neoplastic capillary proliferation secondary to an opportunistic infection by one of two Rochalimaea sp.: R. quintana or R. henselae. Although BA is a recently recognised entity, numerous cases have been reported. Most of the patients affected are reported to have low absolute CD4 lymphocyte counts associated with AIDS. Yet, very few oral cases associated or not with cutaneous lesions have been reported or simply identified. Histopathological and ultrastructural features of one case of oral BA with gingival and palatal lesions are presented. Clinical aspects of oral BA do not hold pathognomonic features and the lesions may resemble either a reactive lesion of the gingiva, pyogenic granuloma or Kaposi's sarcoma. The lesion is characteristically composed of circumscribed lobular capillary proliferations and the presence of granular amphophilic material on haematoxylin and eosin sections surrounded by neutrophils and neutrophilic debris is a clue to diagnosis. Demonstration of bacilli in the interstitium by the Warthin-Starry silver method or, better, by electron microscopy is diagnostic. BA may contribute to the death of the patient but erythromycin has proved to be very effective treatment.

Bacillary angiomatosis in a patient with AIDS

OBJECTIVE

To report the clinical presentation and response to antimicrobial therapy of presumed bacillary angiomatosis in an AIDS patient.

DESIGN

Single case report.

SETTING

A 1058-bed, university teaching hospital.

PATIENT

28-year-old HIV-positive man (T4 lymphocyte count < 3/mm3), who was diagnosed with AIDS in 1984.

RESULTS

The skin lesions responded promptly to treatment with doxycycline and erythromycin.

CONCLUSIONS

Bacillary angiomatosis is an infection that occurs with endstage AIDS. Skin lesions have recognizable characteristics and respond promptly to appropriate antibiotic therapy.