Bartonella quintana and Mycobacterium tuberculosis coinfection in an HIV-infected patient with lymphadenitis

Concurrence of cat-scratch disease and paradoxical tuberculosis-IRIS lymphadenopathy: a case report

BACKGROUND

Mycobacterial infections can cause significant morbidity when cellular immunity is compromised. Patients with AIDS can be affected directly from infection or through mycobacterial IRIS, especially if they are previously untreated for HIV. Herein a case of tuberculous lymphadenitis is reported, which primarily responded to antimicrobials but complicated by IRIS and cat-scratch disease at a later course.

CASE PRESENTATION

A 23-year-old man, intravenous drug user with untreated HIV and HCV infection presented with fever and painful cervical lymphadenopathy. Mycobacterium tuberculosis was isolated from PCR and culture of ultrasound-guided lymph node aspirate and a four-drug anti-TB regimen was subsequently administered, leading to complete resolution of clinical and laboratory abnormalities. Given the patient's CD4 count (67 cells per mm³), antiretroviral treatment started seven weeks after TB treatment initiation. Within the first month of ART fever recurred along with cervical lymph node inflammation. Paradoxical IRIS was considered as the most probable diagnosis but workup expanded, revealing acute Bartonella infection. A posteriori, the patient remembered being scratched by a stray cat two weeks before his new symptoms started. Doxycycline and corticosteroid monotherapy failed to resolve symptoms, whereas a combination of doxycycline for 3 months and methylprednisolone with long-term tapering led to negative follow-up Bartonella antibodies and complete clinical and biochemical response, without recurrence.

CONCLUSIONS

Co-infection with TB and Bartonella presenting with lymphadenitis is unusual. Cat-scratch disease can be a rare clinical presentation of Bartonella infection in patients with AIDS, but coexistence of bartonellosis and paradoxical IRIS has never been reported before. However, physicians treating people living with HIV should be aware of this potential concurrence. Early testing for Bartonella infection could be offered in patients with TB and HIV co-infection in case of acute deterioration or partial response to treatment, especially if they have a history of cat exposure, since clinical picture can be indistinguishable.

Current and past strategies for bacterial culture in clinical microbiology

A pure bacterial culture remains essential for the study of its virulence, its antibiotic susceptibility, and its genome sequence in order to facilitate the understanding and treatment of caused diseases. The first culture conditions empirically varied incubation time, nutrients, atmosphere, and temperature; culture was then gradually abandoned in favor of molecular methods. The rebirth of culture in clinical microbiology was prompted by microbiologists specializing in intracellular bacteria. The shell vial procedure allowed the culture of new species of Rickettsia. The design of axenic media for growing fastidious bacteria such as Tropheryma whipplei and Coxiella burnetii and the ability of amoebal coculture to discover new bacteria constituted major advances. Strong efforts associating optimized culture media, detection methods, and a microaerophilic atmosphere allowed a dramatic decrease of the time of Mycobacterium tuberculosis culture. The use of a new versatile medium allowed an extension of the repertoire of archaea. Finally, to optimize the culture of anaerobes in routine bacteriology laboratories, the addition of antioxidants in culture media under an aerobic atmosphere allowed the growth of strictly anaerobic species. Nevertheless, among usual bacterial pathogens, the development of axenic media for the culture of Treponema pallidum or Mycobacterium leprae remains an important challenge that the patience and innovations of cultivators will enable them to overcome.

Lymph node co-infection of mycobacterium avium complex and cytomegalovirus in an acquired immunodeficiency syndrome patient

Acquired immunodeficiency syndrome patients are known to have an increased tendency for developing opportunistic infections. However, there are no reports of simultaneous lymph node involvement of cytomegalovirus and Mycobacterium avium complex in a human immunodeficiency virus-positive patient. We report a 31-year-old man who presented with acute abdominal pain and tenderness and weight loss. He died a few hours after admission. Autopsy studies showed coinfection of cytomegalovirus, Mycobacterium avium complex and human immunodeficiency virus. Our case emphasizes the need to be careful in evaluating opportunistic infections in severely immunodepressed acquired immunodeficiency syndrome patients. This case report is the first manifestation of acquired immunodeficiency syndrome in this patient.

Bartonella spp. infection in HIV positive individuals, their pets and ectoparasites in Rio de Janeiro, Brazil: serological and molecular study

BACKGROUND

Bartonella is the agent of cat-scratch disease, but is also responsible for more severe conditions such as retinitis, meningoencephalitis, endocarditis and bacillary angiomatosis. Its seroprevalence is unknown in Brazil.

METHODS

Patients in an AIDS clinic, asymptomatic at the time of the study, were enrolled prospectively. They answered a structured questionnaire and had blood taken for serological and molecular assays. Cat breeder's pets were tested serologically and collected ectoparasites were tested by molecular biology techniques. Blood donors, paired by age and sex, were tested for Bartonella IgG antibodies.

RESULTS

125 HIV positive patients with a median age of 34 were studied; 61 were male and 75% were on HAART. Mean most recent CD4 count was 351-500 cells/mm(3). A high rate of contact with ticks, fleas and lice was observed. Bartonella IgG seroreactivity rate was 38.4% in HIV positive individuals and breeding cats was closely associated with infection (OR 3.6, CI 1.1-11.9, p<0.05). No difference was found between the sexes. Titers were 1:32 in 39 patients, 1:64 in seven, 1:128 in one and 1:256 in one. In the control group, IgG seroreactivity to Bartonella spp. was 34%, and female sex was correlated to seropositivity. Fourteen of 61 (23%) males vs 29/64 (45.3%) females were seroreactive to Bartonella (OR 2.8, CI 1.2-6.5, p<0.01). Titers were 1:32 in 29 patients, 1:64 in ten and 1:128 in four.

CONCLUSIONS

Bartonella spp. seroprevalence is high in HIV positive and in blood donors in Rio de Janeiro. This may be of public health relevance.

Cost-effectiveness of blood agar for isolation of mycobacteria

Background

Mycobacterium species are grown using specific media that increase laboratory cost, thus hampering their diffusion in resource-limited countries. Preliminary data suggested that versatile blood agar may be also used for mycobacterial culture.

Methodology

We examined the growth of 41 different Mycobacterium species on 5% blood agar. Over a 24-month period we analysed isolation of mycobacteria after parallel inoculation of clinical specimens into both a reference automated system (BACTEC 9000 MB broth) and 5% blood agar slant tubes, after NaOH decontamination, and compared the cost of performing 1,000 analyses using these two techniques.

Conclusions

Mycobacterium reference species cultured on blood agar, with the exception of Mycobacterium ulcerans. Inoculation of 1,634 specimens yielded 95 Mycobacterium isolates. Blood agar performed significantly more efficiently than BACTEC 9000 MB broth (94 vs 88 isolates, P = 0.03). Decontamination of Candida albicans in 5 specimens by addition of amphotericin B in blood agar yielded one more M. tuberculosis isolate that could not be isolated in BACTEC broth. Uneven distribution of time to culture positivity for M. tuberculosis had a median (range) of 19±5 days using blood agar and 26±6 days using BACTEC 9000 MB broth. Cost for 1,000 analyses in France was estimated to be of 1,913 euros using the blood agar method and 8,990 euros using the BACTEC 9000 MB method. Blood agar should be regarded as a first-line medium for culturing Mycobacterium species. It saves time, is cost-effective, is more sensitive than, and at least as rapid as the automated method. This is of particular importance for resource-limited countries in which the prevalence of tuberculosis is high.

Mycobacteria are organisms responsible for animal and human infections comprising tuberculosis due to Mycobacterium tuberculosis and other opportunistic infections. Such infections require specific antibiotic treatment and prevention of secondary cases in the occurrence of pulmonary tuberculosis. The accurate diagnosis of mycobacteria infection is therefore of prime importance. Isolation and culture of mycobacteria from diseased clinical specimens is the gold standard for diagnosis. It relied for decades on the use of specific isolation media, resulting in most laboratories not attempting such diagnosis. Alternatively, specific automates and culture broths are available only in developed countries. We herein demonstrate that blood agar, a basic medium widely and routinely used in laboratories worldwide, is suitable for the isolation and culture of mycobacteria encountered in human pathology, including tuberculosis. It performed at least as well as reference culture broth. Morever, using blood agar was cost-effective. Blood agar should be recommended as a routine medium for the isolation of most pathogenic organisms, including mycobacteria, both in developing and developed countries.

Bartonella quintana characteristics and clinical management

The pathogen is reemerging in the United States and Europe and is responsible for a number of clinical conditions.

Bartonella quintana, a pathogen that is restricted to human hosts and louse vectors, was first characterized as the agent of trench fever. The disease was described in 1915 on the basis of natural and experimental infections in soldiers. It is now recognized as a reemerging pathogen among homeless populations in cities in the United States and Europe and is responsible for a wide spectrum of conditions, including chronic bacteremia, endocarditis, and bacillary angiomatosis. Diagnosis is based on serologic analysis, culture, and molecular biology. Recent characterization of its genome allowed the development of modern diagnosis and typing methods. Guidelines for the treatment of B. quintana infections are presented.