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Bartonella henselae bacilli detected in vitrectomy aspirates in a patient with massive vitreous opacity with total retinal detachment.

PURPOSE: To present endophthalmitis-like massive vitreous opacity as a manifestation of cat-scratch disease. METHODS: Report of a case. RESULTS: A 47-year-old man developed massive vitreous opacity and total retinal detachment in his right eye after a four-month period of uveitis, which was controlled with oral prednisolone. During the diagnostic vitrectomy, a massive fluffy white opacity adhering to the detached retina was shaved using a vitreous cutter. Further surgical procedures to reattach the retina were not pursued because of the poor state of the infected retina. Pathological examination of the vitreous aspirates revealed pleomorphic bacilli. The serological testing done at referral revealed an IgG titer positive for Bartonella henselae and culture of the vitreous proved the infection a month later. With a mixture of oral sulfamethoxazole (1600 mg daily) and trimethoprim (320 mg daily), the intraocular inflammation subsided. CONCLUSION: Rapid progression of massive vitreous opacity with total retinal detachment, mimicking endophthalmitis, can occur in cat-scratch disease.

Anti-Infective Agents↗

[Polymerase chain reaction (PCR) for microbiological diagnosis in refractory infectious keratitis: a clinical study in 16 patients].

BACKGROUND: The identification of the causative pathogen in infectious keratitis is possible in only 60% of the cases. The aim of this study was to show if this number increases by the use of PCR. PATIENTS AND METHODS: In a series of 16 eyes with infectious keratitis corneal specimens were collected for culture and PCR. Serology (HSV, VZV, and Borrelia) was performed in all eyes, with exception of the 4 eyes presenting an acute form of keratitis, which obviously was bacterial origin. RESULTS: In all 4 cases of acute keratitis the causative pathogen (Pseudomonas aeruginosa) was detected by both culture and PCR. Of the remaining 12 eyes PCR was capable to identify the causative pathogen in 11 eyes. In 3 eyes herpes simplex virus was detected, in 3 eyes Moraxella catharalis, in 2 eyes Borrelia burgdorferii, in 2 eyes varizella zoster virus, and in 1 eye Bartonella henselae. Culture was positive in only 2 eyes, infected by Moraxella catharalis. CONCLUSIONS: PCR is a useful supplement in the microbiological diagnostic of infectious keratitis, in particular if only a small amount of pathogens are available (non-acute form) or if the eye has been treated by antibiotics prior to the microbiological diagnostic.

Chronic Disease↗

Distribution, diversity, and host specificity of Bartonella in rodents from the Southeastern United States.

A number of Bartonella isolates were obtained from seven species of rodents sampled from 12 geographic sites representing the major biotic communities of the southeastern United States. Bartonella were isolated from the blood of 42.2% of 279 tested rodents. The highest prevalence of infection typically occurred among the most commonly captured species in the rodent community. Four phylogenetic groups, uniting 14 genotypic variants of Bartonella, were identified by sequence analysis of the citrate synthase gene. The level of sequence homology between genotypic groups varied from 88.8% to 96.4%, and the degree of homology among variants within groups was > or = 97%. Cotton rats (Sigmodon hispidus) harbored up to three phylogenetic groups of Bartonella at a single site, and Bartonella of two phylogenetic groups were isolated from a single rodent. All the Bartonella isolated from three species of Peromyscus clustered in a single distinct phylogenetic group, suggesting some host specificity may occur. Mouse ascitic fluids produced in BALB/c mice inoculated with Bartonella of three phylogenetic groups demonstrated high indirect fluorescent antibody (IFA) titers to homologous antigens. However, use of eight Bartonella antigens in an IFA test with sera from 394 wild-caught rodents resulted in either little or extremely low titers of antibody.

Animals↗

16S/23S rRNA intergenic spacer regions for phylogenetic analysis, identification, and subtyping of Bartonella species.

Species of the genus Bartonella are currently recognized in growing numbers and are involved in an increasing variety of human diseases, mainly trench fever, Carrion's disease, bacillary angiomatosis, endocarditis, cat scratch disease, neuroretinitis, and asymptomatic bacteremia. Such a wide spectrum of infections makes it necessary to develop species and strain identification tools in order to perform phylogenetic and epidemiological studies. The 16S/23S rRNA intergenic spacer region (ITS) was sequenced for four previously untested species, B. vinsonii subsp. arupensis, B. tribocorum, B. alsatica, and B. koehlerae, as well as for 28 human isolates of B. quintana (most of them from French homeless people), six human or cat isolates of B. henselae, five cat isolates of B. clarridgeiae, and four human isolates of B. bacilliformis. Phylogenetic trees inferred from full ITS sequences of the 14 recognized Bartonella species using parsimony and distance methods revealed high statistical support, as bootstrap values were higher than those observed with other tested genes. Five well-supported lineages were identified within the genus and the proposed phylogenetic organization was consistent with that resulting from protein-encoding gene sequence comparisons. The ITS-derived phylogeny appears, therefore, to be a useful tool for investigating the evolutionary relationships of Bartonella species and to identify Bartonella species. Further, partial ITS amplification and sequencing offers a sensitive means of intraspecies differentiation of B. henselae, B. clarridgeiae, and B. bacilliformis isolates, as each strain had a specific sequence. The usefulness of this approach in epidemiological investigations should be highlighted. Among B. quintana strains, however, the genetic heterogeneity was low, as only three ITS genotypes were identified. It was nevertheless sufficient to show that the B. quintana population infecting homeless people in France was not clonal.

Animals↗

Characterization of Bartonella henselae-specific immunity in BALB/c mice.

BALB/c mice were inoculated with Bartonella henselae by both systemic and mucosal routes. Culture analysis of tissues from mice infected intraperitoneally with a high dose of B. henselae yielded positive results 24 hr after infection. However, culture analysis of blood taken between 6 hr and 7 days after infection from groups receiving live B. henselae were negative. Following intraperitoneal infection, B. henselae was detected by polymerase chain reaction in liver and mesenteric lymph nodes by 6 hr and up to 7 days after infection in liver, kidney and spleen tissue. Enzyme-linked immunosorbent assay (ELISA) of serum samples collected as early as 13 days after infection indicated humoral immune responses to B. henselae. Specific humoral responses remained through week 6. Analysis of faecal samples revealed induction of B. henselae-specific immunoglobulin A by day 28 after infection. In addition, B. henselae-specific cellular responses were indicated by a positive delayed-type hypersensitivity and a T helper 1 (Th1) (CD4+ T cell)-type cytokine response following in vitro stimulation of splenocytes. The significance and implications of these data in relation to B. henselae infections are discussed.

Animals↗

The X-linked hyper-IgM syndrome: clinical and immunologic features of 79 patients.

The X-linked hyper-IgM (XHIGM) syndrome is an uncommon primary immunodeficiency disease caused by mutations in the gene for CD40 ligand and characterized by normal or elevated serum IgM, reduced levels of IgG and IgA, and defective T-cell function. Because of its rarity, it has been difficult for any single investigator or institution to develop a comprehensive clinical picture of this disorder. Accordingly, a national registry was developed in the United States to provide demographic, genetic, immunologic, and clinical information on a relatively large number of patients with the XHIGM syndrome.A total of 79 patients from 60 unrelated families were registered between January 1997 and July 2002. The estimated minimal incidence was approximately 1/1,030,000 live births. All of the patients had significant IgG deficiency and most had IgA deficiency, but only one-half had elevated IgM levels. Most patients presented initially with a history of an increased susceptibility to infection including Pneumocystis carinii pneumonia. The average age of diagnosis was significantly earlier in patients born into a family with a previously affected individual. However, only one-third of the patients born into a family with a previously affected individual were diagnosed exclusively because of the presence of the positive family history before any clinical symptoms developed. Over half the patients developed symptoms of immunodeficiency and were diagnosed by 1 year of age, and over 90% by 4 years of age. The most prominent clinical infections were pneumonia (81% of patients), upper respiratory infections (49%) including sinusitis (43%) and recurrent otitis (43%), recurrent/protracted diarrhea (34%), central nervous system infections (14%), sepsis (13%), cellulitis (13%), hepatitis (9%), and osteomyelitis (1%). In addition to infections caused by encapsulated bacteria, opportunistic infections were relatively common and were caused by P. carinii, members of the herpes virus family (including cytomegalovirus), Cryptosporidium, Cryptococcus, Candida, Histoplasma, and Bartonella. Sclerosing cholangitis occurred in 5 patients and in 4 of these was associated with Cryptosporidium infection. Eight patients had died at the time of their entry into the Registry; 2 of pneumonia (1 P. carinii and 1 cytomegalovirus), 2 of encephalitis (1 ECHO virus and 1 cytomegalovirus), 2 of malignancy (both hepatocellular carcinoma), 1 of sclerosing cholangitis caused by Cryptosporidium, and 1 of hemolytic uremic syndrome.

Adolescent↗

Pericardial effusion in a homeless man due to Bartonella quintana.

Bartonella quintana may cause trench fever, endocarditis, bacillary angiomatosis, and chronic bacteremia, and a reemergence among homeless populations in cities has been noted. Pericarditis from Rickettsia conorii and Coxiella burnetii infection has been described, but there have been no reports of pericarditis due to Bartonella spp. We report a case of pericardial effusion due to Bartonella quintana in a homeless man, diagnosed on the basis of PCR detection of Bartonella quintana in a pericardial biopsy sample and a fourfold rise in antibody titers. The patient recovered within 2 weeks with antibiotics active against bartonellae.

Adult↗

Coinfection with multiple tick-borne pathogens in a Walker Hound kennel in North Carolina.

Both dogs and humans can be coinfected with various Ehrlichia, Bartonella, Rickettsia, and Babesia species. We investigated a kennel of sick Walker Hounds and their owners in southeastern North Carolina for evidence of tick-borne infections and associated risk factors. A high degree of coinfection was documented in the dog population. Of the 27 dogs, 26 were seroreactive to an Ehrlichia sp., 16 to Babesia canis, and 25 to Bartonella vinsonii, and 22 seroconverted to Rickettsia rickettsii antigens. According to PCR results, 15 dogs were infected with Ehrlichia canis, 9 with Ehrlichia chaffeensis, 8 with Ehrlichia ewingii, 3 with Ehrlichia equi, 9 with Ehrlichia platys, 20 with a Rickettsia species, 16 with a Bartonella species, and 7 with B. canis. The detection of DNA from any Ehrlichia species was associated with clinical illness and with concurrent B. canis infection (by PCR). Both E. canis and an uncharacterized Rickettsia species appeared to result in chronic or recurrent infection. Death in the dog population was associated with living in a dirt lot rather than the concrete kennel. Of 23 people on whom serologic testing was conducted, eight were seroreactive to Bartonella henselae, one to E. chaffeensis, and one to R. rickettsii antigen; however, none had clinical or hematologic abnormalities consistent with illness caused by these organisms. We conclude that kennel dogs with heavy tick exposure can be infected at a high rate with multiple, potentially zoonotic, tick-borne pathogens. In addition, our findings further illustrate the utility of PCR for documenting coinfection with tick-transmitted pathogens.

Animals↗

Cutaneous manifestations of opportunistic infections in patients infected with human immunodeficiency virus.

Bacillary angiomatosis (BA) presents most commonly as a cutaneous disease and is caused by two organisms. Bartonella (Rochalimaea) henselae and Bartonella (Rochalimaea) quintana. Biopsy confirmation of cutaneous BA is essential because lesions can mimic nodular Kaposi's sarcoma in appearance. Although the vast majority of human immunodeficiency virus (HIV)-infected patients with BA have CD4 lymphocyte counts of less than 100 cells per mm3, the disease responds well to antimicrobial therapy. Staphylococcus aureus is the most common bacterial skin pathogen affecting HIV-infected patients. The prevalence of skin disease due to S. aureus may be explained by high nasal carriage rates for the organism ( > or = 50%) and altered immune function in conjunction with an impaired cutaneous barrier. Herpes simplex virus causes mucocutaneous disease early in the course HIV infection and ulcerative lesions at any site in advanced HIV infection. Herpes zoster is common early in the course of HIV infection; recurrent and disseminated herpes zoster infections are characteristic of patients with advanced HIV disease. Acyclovir resistance is usually seen in patients with large, untreated, ulcerative lesions of herpes simplex virus and in patients with chronic, verrucous lesions of varicella-zoster virus. Cutaneous cryptococcosis, histoplasmosis, and coccidiomycosis are markers of disseminated disease and require biopsy confirmation. Scabies is easily diagnosed but may be atypical in presentation and difficult to eradicate in advanced HIV disease.

AIDS-Related Opportunistic Infections↗

Isolation of Bartonella washoensis from a dog with mitral valve endocarditis.

We report the first documented case of Bartonella washoensis bacteremia in a dog with mitral valve endocarditis. B. washoensis was isolated in 1995 from a human patient with cardiac disease. The main reservoir species appears to be ground squirrels (Spermophilus beecheyi) in the western United States. Based on echocardiographic findings, a diagnosis of infective vegetative valvular mitral endocarditis was made in a spayed 12-year-old female Doberman pinscher. A year prior to presentation, the referring veterinarian had detected a heart murmur, which led to progressive dyspnea and a diagnosis of congestive heart failure the week before examination. One month after initial presentation, symptoms worsened. An emergency therapy for congestive heart failure was unsuccessfully implemented, and necropsy evaluation of the dog was not permitted. Indirect immunofluorescence tests showed that the dog was strongly seropositive (titer of 1:4,096) for several Bartonella antigens (B. vinsonii subsp. berkhoffii, B. clarridgeiae, and B. henselae), highly suggestive of Bartonella endocarditis. Standard aerobic and aerobic-anaerobic cultures were negative. However, a specific blood culture for Bartonella isolation grew a fastidious, gram-negative organism 7 days after being plated. Phenotypic and genotypic characterizations of the isolate, including partial sequencing of the citrate synthase (gltA), groEL, and 16S rRNA genes, indicated that this organism was identical to B. washoensis. The dog was seronegative for all tick-borne pathogens tested (Anaplasma phagocytophilum, Ehrlichia canis, and Rickettsia rickettsii), but the sample was highly positive for B. washoensis (titer of 1:8,192) and, according to indirect immunofluorescent-antibody assay, weakly positive for phase II Coxiella burnetii infection.

Animals↗

The VirB type IV secretion system of Bartonella henselae mediates invasion, proinflammatory activation and antiapoptotic protection of endothelial cells.

Bartonella henselae is an arthropod-borne zoonotic pathogen causing intraerythrocytic bacteraemia in the feline reservoir host and a broad range of clinical manifestations in incidentally infected humans. Remarkably, B. henselae can specifically colonize the human vascular endothelium, resulting in inflammation and the formation of vasoproliferative lesions known as bacillary angiomatosis and bacillary peliosis. Cultured human endothelial cells provide an in vitro system to study this intimate interaction of B. henselae with the vascular endothelium. However, little is known about the bacterial virulence factors required for this pathogenic process. Recently, we identified the type IV secretion system (T4SS) VirB as an essential pathogenicity factor in Bartonella, required to establish intraerythrocytic infection in the mammalian reservoir. Here, we demonstrate that the VirB T4SS also mediates most of the virulence attributes associated with the interaction of B. henselae during the interaction with human endothelial cells. These include: (i) massive rearrangements of the actin cytoskeleton, resulting in the formation of bacterial aggregates and their internalization by the invasome structure; (ii) nuclear factor kappaB-dependent proinflammatory activation, leading to cell adhesion molecule expression and chemokine secretion, and (iii) inhibition of apoptotic cell death, resulting in enhanced endothelial cell survival. Moreover, we show that the VirB system mediates cytostatic and cytotoxic effects at high bacterial titres, which interfere with a potent VirB-independent mitogenic activity. We conclude that the VirB T4SS is a major virulence determinant of B. henselae, required for targeting multiple endothelial cell functions exploited by this vasculotropic pathogen.

Actin Cytoskeleton↗

Pet ownership in immunocompromised children--a review of the literature and survey of existing guidelines.

Pet ownership has been associated with both emotional and physical health benefits. However, owning pets may also pose health risks to immunocompromised patients through zoonotic transmission of disease. Our initial impression was that there is a lack of any evidence base in information given by health care professionals regarding these risks. We therefore aimed to produce evidence-based guidelines addressing this issue. A Pubmed search was undertaken and a variety of literature on zoonoses reviewed. Existing guidelines were evaluated and a survey of all Paediatric Oncology Centres in the UK performed. There is a paucity of level 1 and 2 data addressing this issue and clearly more studies, particularly Randomised Controlled Trials (RCTs), are required. Nevertheless, general themes emerged and certain specific guidance was produced based on that produced by the Centres for Disease Control and Prevention in the US. Animal-associated pathogens of concern include Toxoplasma gondii, Cryptosporidium spp., Salmonella spp., Campylobacter spp., Giardia lamblia, Rhodococcus equi, Bartonella spp., Bordetella bronchiseptica, Chlamydia psittaci and dermatophytes. Despite this, the literature would suggest that with the exception of Bartonella henselae and dermatophytes only a relatively small number of infections in people are likely to be associated with pet contact. The majority of pet species do not appear to pose a major risk to immunocompromised children. Some animals, particularly reptiles, should be avoided because of the high risk of salmonellosis. Guidelines include general advice on good hygiene practices, veterinary care, pet foods, purchasing of new pets and age restrictions. Health care professionals should actively enquire about household pets and provide accurate information and practical advice on how to minimise the risk of infection. However, the overall benefits of the human-animal bond must be considered and with proper handling and husbandry immunocompromised patients should be able to continue to enjoy the significant benefits of pet ownership.

Age Factors↗

Frontal and stealth attack strategies in microbial pathogenesis.

Interactions between microbes and human hosts can range from a benign, even symbiotic collaboration to a competition that may turn fatal--resulting in death of the host, the microbe or both. Despite advances that have been made over the past decades in understanding microbial pathogens, more people worldwide still die every year from infectious disease than from any other cause. This highlights the relevance of continuing to probe the mechanisms used by microorganisms to cause disease, and emphasizes the need for new model systems to advance our understanding of host-pathogen interactions.

Bartonella↗

[Hepatic and splenic micro-abscess in cat scratch disease. Report of a case].

Cat-scratch disease (CSD) is an infection caused by a gram-negative bacillus known as Bartonella Henselae. Hepatosplenic disease occurs in only 0.3-0.7% of patients. In this report we describe a 7-year-old male presented with a 4-week history of fever, after diagnosis of CSD with regional lymphoadenitis. Ultrasonography and tomography identified hepatic and splenic abscesses. Antibiotic treatment for three months was associated with resolution of lesions. In Patients affected by CSD, ultrasonography and tomography permit to identify hepatic and/or splenic lesions, indicating systemic CSD.

Abscess↗

Experimental infection of human body lice with Acinetobacter baumannii.

The human body louse is currently recognized as a vector of Rickettsia prowazekii, Borrelia recurrentis, and Bartonella quintana. Previous studies have reported the isolation of Acinetobacter baumannii from the body lice of homeless patients. To study how the body louse acquires A. baumannii, we infected a rabbit by infusing 2 x 10(6) colony-forming units of the louse strain of A. baumannii. Two hundred body lice were infected by feeding on the bacteremic rabbit and compared with 200 uninfected lice and two groups of 200 lice feeding on rabbits infected either with another strain of A. baumannii or A. lwoffii. Each louse group received maintenance feedings once a day on another seronegative rabbit. Body lice that fed on rabbits infused with each Acinetobacter species demonstrated a generalized infection. The body lice did not transmit their infection to the nurse rabbit by bite while feeding or to their progeny (eggs and larvae). The lice excreted living Acinetobacter species within their feces. Only the louse strain of A. baumannii was pathogenic for the body louse. An increased mortality rate was observed between the second and third days post-infection; however, they remained infected for their lifespan.

Acinetobacter Infections↗

Bartonella henselae prevalence in domestic cats in California: risk factors and association between bacteremia and antibody titers.

The isolation of Bartonella henselae, the agent of cat scratch disease, from the blood of naturally infected domestic cats and the demonstration that cats remain bacteremic for several months suggest that cats play a major role as a reservoir for this bacterium. A convenience sample of 205 cats from northern California was selected between 1992 and 1994 to evaluate the B. henselae antibody and bacteremia prevalences and to determine the risk factors and associations between bacteremia and antibody titers. B. henselae was isolated from the blood of 81 cats (39.5%). Forty-two (52%) of these bacteremic cats were found to be infected with > or = 1,000 CFU/ml of blood. Impounded or former stray cats were 2.86 (95% confidence interval [CI] = 1.94, 4.22) times more likely to be bacteremic than the pet cats. Young cats ( < 1 year old) were more likely than adult cats to be bacteremic (relative risk = 1.64; (95% CI = 1.19, 2.28). Bacteremic cats were more likely than nonbacteremic cats to be infested with fleas (relative risk = 1.64; 95% CI = 1.38, 1.96). No association between B. henselae infection and feline immunodeficiency virus antibody prevalence was observed. Eighty-one percent of the cats (166 of 205) tested positive for B. henselae antibodies, and titers were higher in bacteremic than in nonbacteremic cats. Multiple logistic regression analysis indicated that younger age and seropositivity for B. henselae antibodies were associated with bacteremia. Serological screening for Bartonella antibodies may not be useful for the identification of bacteremic cats (positive predictive value = 46.4%), but the lack of antibodies to B. henselae was highly predictive of the absence of bacteremia (negative predictive value = 89.7%). Seronegative cats may be more appropriate pets for immunocompromised individuals who are at increased risk for developing severe B. henselae disease.

Aging↗