Serological response to "Rochalimaea henselae" antigen in suspected cat-scratch disease

Optic Neuritis and Vertebral Osteomyelitis: An Uncommon Presentation of Cat-Scratch Disease

In cat-scratch disease (CSD), hematogenous spread may result in atypical presentations. Ocular manifestations develop in a minority of patients, with treatment being important in reducing long-term visual sequelae. Bone infection is rare. We present the case of a 52-year-old woman, with close contact with cats, reporting acute unilateral blurred vision and presenting papilledema, optic disc pallor, and peripapillary hemorrhage. Etiologic study of optic neuritis revealed an elevated positive Bartonella IgG; hence, treatment for CSD with doxycycline plus rifampin and corticosteroids was started. Concomitant lumbar pain of increasing intensity warranted magnetic resonance imaging, which revealed L3-L4 vertebral osteomyelitis with spondylodiscitis. Given the temporal link with CSD diagnosis and the significant clinical improvement since its treatment was started, an etiologic link was presumed and antibiotics were prolonged. This case stands out for the presence of distinct atypical CSD manifestations in the same patient. Further studies are needed to determine the optimal treatment for rare manifestations, particularly bone infection.

A case of hepatosplenic cat scratch disease with hemophagocytic lymphohistiocytosis

Cat scratch disease (CSD) is associated with Bartonella henselae (B. henselae) infection caused by cat scratches or bites. It typically presents with lymphadenitis and fever. However, there are atypical cases such as hepatosplenic CSD, which presents with specific lesions in the liver and spleen. Hemophagocytic lymphohistiocytosis (HLH) is a rare and severe multisystem disorder triggered by infections, cancers, or autoimmune diseases. We experienced a rare case of hepatosplenic CSD with HLH in a non-immunocompromised adult. A 78-year-old woman complained of fever and fatigue. Laboratory tests revealed anemia and liver dysfunction; abdominal contrast-enhanced computed tomography (CT) revealed splenomegaly and nodular hypodense areas in the spleen. In addition, the levels of ferritin and serum soluble IL-2R were markedly elevated, so clinical diagnosis of HLH was made. Positron emission tomography/CT revealed diffuse fluorodeoxyglucose uptake in the liver and spleen suggesting malignant lymphoma, while the pathological findings from liver biopsy suggested infectious diseases. Although she had no cat bites and scratches, she had many cats; therefore, serum B. henselae antibody titers were measured. The B. henselae IgG and IgM titer were 1:128 and 1:20; thus, she was diagnosed with hepatosplenic CSD. Patients with hepatosplenic nodular lesions and contact with cats should be considered for this disease.

The Uterine Environment and Childhood Obesity Risk: Mechanisms and Predictions

PURPOSE OF REVIEW

Childhood obesity is a growing health problem in many populations, hence the urgent need to unravel the underlying mechanisms. Some evidence suggests that exposure to suboptimal intrauterine environments can program foetal metabolic health, with adverse consequences in later life, including susceptibility to childhood obesity.

FINDINGS

Factors such as high and low foetal birth weight, excessive gestational-weight-gain, maternal stress and smoking are all associated with increased risk of childhood obesity in observational studies. Animal models, where both genetic background and the postnatal environment can be carefully controlled, suggest that several different mechanisms, including epigenetic changes, dysregulation of adipose tissue development and programming of appetite, may be key drivers of developmental programming of childhood obesity. However, the influence of genetics and the post-natal environment are much more difficult to disentangle as independent effects in human studies, which are also complicated by low follow-up rates. Suboptimal intrauterine environments interact with maternal and foetal genetics and with the postnatal environment to contribute to the risk of childhood obesity. Maternal metabolic challenges, for example obesity and insulin resistance, contribute to the risk of foetal overgrowth and subsequent adiposity in childhood. To protect the long-term health of populations, research focusing on effective means of identifying and intervening in the transgenerational cycle of childhood obesity is required.

Diversity and Phylogeny of Cattle Ixodid Ticks and Associated Spotted Fever Group Rickettsia spp. in Tunisia

Tick-borne rickettsioses are mainly caused by obligate intracellular bacteria belonging to the spotted fever group (SFG) of the Rickettsia genus. So far, the causative agents of SFG rickettsioses have not been detected in cattle ticks from Tunisia. Therefore, the aim of this study was to investigate the diversity and phylogeny of ticks associated with cattle from northern Tunisia and their associated Rickettsia species. Adult ticks (n = 338) were collected from cattle in northern Tunisia. The obtained ticks were identified as Hyalomma excavatum (n = 129), Rhipicephalus sanguineus sensu lato (n = 111), Hyalomma marginatum (n = 84), Hyalomma scupense (n = 12) and Hyalomma rufipes (n = 2). After DNA extraction from the ticks, 83 PCR products based on the mitochondrial 16S rRNA gene were sequenced and a total of four genotypes for Rh. sanguineus s.l., two for Hy. marginatum and Hy. excavatum and only one for Hy. scupense and Hy. rufipes were recorded, with the occurrence of one, two and three novel genotypes, respectively, for Hy. marginatum, Hy. excavatum and Rh. sanguineus s.l. mitochondrial 16S rRNA partial sequences. The tick DNA was tested for the presence of Rickettsia spp. by using PCR measurements and sequencing targeting three different genes (ompB, ompA and gltA). Of the 338 analyzed ticks, 90 (26.6%), including 38 (34.2%) Rh. sanguineus s.l., 26 (20.1%) Hy. excavatum, 25 (29.8%) Hy. marginatum and one (50%) Hy. rufipes tick, were positive for Rickettsia spp. Based on 104 partial sequences of the three analyzed genes, the BLAST analysis and phylogenetic study showed the infection of Hy. excavatum, Hy. marginatum and Rh. sanguineus s.l. tick specimens with R. massiliae, R. aeschlimannii and R. sibirica subsp. mongolitimonae and one Hy. rufipes tick specimen with R. aeschlimannii. In addition, coinfection with R. massiliae and R. aeschlimannii was reported in one Hy. marginatum and one Rh. sanguineus s.l. tick specimen, while a coinfection with R. massiliae and R. sibirica subsp. mongolitimonae was recorded in one Rh. sanguineus s.l. tick specimen. In conclusion, our study reports, for the first time in Tunisia, the infection of cattle ticks belonging to Hyalomma and Rhipicephalus genera with zoonotic Rickettsia species belonging to the SFG group.

Bartonella Species in Cambodia, Ghana, Laos, and Peru: Results from Vector and Serosurveys

Background: Bartonella species are fastidious gram-negative vector-borne bacteria with a wide range of mammalian reservoirs. While it is understood that some species of Bartonella are human pathogens, the extent of human exposure to Bartonella species (both pathogenic and nonpathogenic) is yet to be fully understood. Materials and Methods: To this end, residual sera from participants enrolled in undifferentiated fever studies in Cambodia, Ghana, Laos, and Peru were screened for the presence of IgG antibodies against Bartonella quintana and Bartonella henselae, using the FOCUS diagnostics Dual Spot- Bartonella IgG Immunofluorescence assay. Forty-eight patients with suspected or confirmed Bartonella bacilliformis exposure or infection in Peru were screened to assess cross-reactivity of the FOCUS assay for IgG against other Bartonella species. Results: Ten of 13 patients with confirmed B. bacilliformis infection were Bartonella-specific IgG positive, and overall, 36/48 of the samples were positive. In addition, 79/206, 44/200, 101/180, and 57/100 of the samples from Peru, Laos, Cambodia, and Ghana, respectively, were Bartonella-specific IgG positive. Furthermore, ectoparasite pools from Cambodia, Laos, and Peru were tested using quantitative real-time PCR (qPCR) for the presence of Bartonella DNA. Of the sand fly pools collected in Peru, 0/196 were qPCR positive; 15/140 flea pools collected in Cambodia were qPCR positive; while 0/105 ticks, 0/22 fleas, and 0/3 louse pools collected in Laos tested positive for Bartonella DNA. Conclusion: Evidence of Bartonella in fleas from Cambodia supports the possibility that humans are exposed to Bartonella through this traditional vector. However, Bartonella species were not found in fleas, ticks, or lice from Laos, or sand flies from Peru. This could account for the lower positive serology among the population in Laos and the strictly localized nature of B. bacilliformis infections in Peru. Human exposure to the Bartonella species and Bartonella as a human pathogen warrants further investigation.

Limitations of Serological Diagnosis of Typical Cat Scratch Disease and Recommendations for the Diagnostic Procedure

Introduction

Cat scratch disease (CSD) is the most common cause of bacterial infectious lymphadenopathy, especially in children, but its diagnosis still remains challenging. Serological assays are widely applied due to their simplicity and the non-invasive sampling. However, these techniques present several limitations, including not well-defined antigen preparation, assay conditions and cutoff titers, severe cross-reactions with other species and organisms, and the notably ranging seroprevalence in the normal population. The objective of this study is to review the literature in order to determine the best diagnostic procedure for the diagnosis of CSD.

Methods

Databases including PubMed, Medline, Google Scholar, and Google were searched to determine the best diagnostic procedure for the diagnosis of CSD. A total of 437 papers were identified and screened, and after exclusion of papers that did not fulfill the including criteria, 63 papers were used.

Results

It was revealed that sensitivities of serological assays varied from 10% to 100%. Indeed, more than half of the studies reported a sensitivity lower than 70%, while 71% of them had a sensitivity lower than 80%. Moreover, specificities of serological assays ranged from 15% to 100%, with 25 assays reporting a specificity lower than 90%.

Conclusion

It is considered that molecular assays should be the gold standard technique for CSD confirmation, and physicians are reinforced to proceed to lymph node biopsy in suspicious CSD cases.

Cat Scratch Disease-associated Encephalitis Followed by Parkinsonism

Cat scratch disease (CSD) is a zoonotic infection caused by Bartonella henselae typically resulting in self-limited regional lymphadenopathy. Encephalitis is a complication with a supposedly benign prognosis, but we encountered an exceptional case. A 19-year-old Japanese woman presented with status epilepticus. She was diagnosed with CSD-associated encephalitis based on her history of contact with a kitten and a high titre of serum IgG to B. henselae. Multimodal treatment ameliorated her encephalitis, but neurological sequelae including spastic paraparesis, persisted. After several months, she developed age-disproportionate parkinsonism inconsistent with a neurodegenerative disease. In conclusion, CSD-associated encephalitis can result in severe neurological sequelae and post-encephalitic parkinsonism.

Adaptive immune defense prevents Bartonella persistence upon trans-placental transmission

Vertical transmission of Bartonella infection has been reported for several mammalian species including mice and humans. Accordingly, it is commonly held that acquired immunological tolerance contributes critically to the high prevalence of Bartonellae in wild-ranging rodent populations. Here we studied an experimental model of Bartonella infection in mice to assess the impact of maternal and newborn immune defense on vertical transmission and bacterial persistence in the offspring, respectively. Congenital infection was frequently observed in B cell-deficient mothers but not in immunocompetent dams, which correlated with a rapid onset of an antibacterial antibody response in infected WT animals. Intriguingly, B cell-deficient offspring with congenital infection exhibited long-term bacteremia whereas B cell-sufficient offspring cleared bacteremia within a few weeks after birth. Clearance of congenital Bartonella infection resulted in immunity against bacterial rechallenge, with the animals mounting Bartonella-neutralizing antibody responses of normal magnitude. These observations reveal a key role for humoral immune defense by the mother and offspring in preventing and eliminating vertical transmission. Moreover, congenital Bartonella infection does not induce humoral immune tolerance but results in anti-bacterial immunity, questioning the contribution of neonatal tolerance to Bartonella prevalence in wild-ranging rodents.

Vertical transmission of Bartonella has been reported in small rodents but also in at least one human case. The prevalence of these bacteria in the wild is extremely high. While a protective antibody response clearly controls the infection in the experimental model, observations from the wild indicate that this might not always be the case. This led to the long-standing hypothesis that Bartonella might induce immunological tolerance. To study if transplacental transmission of these bacteria results in immunological tolerance in the offspring, we used a mouse model of Bartonella taylorii infection. We infected wildtype and immunocompromised females (Rag1-/- and μMT) and observed that transmission only occurred in mothers lacking a functional B-cell response. Immunocompetent offspring, however, cleared the infection and were protected from reinfection by the same Bartonella strain due to the presence of protective antibodies. Thus, even though transplacental transmission of Bartonella is possible under the right circumstances, we find no evidence for immunological tolerance or persistent infection in the offspring.

Molecular Diagnosis of Cat Scratch Disease: a 25-Year Retrospective Comparative Analysis of Various Clinical Specimens and Different PCR Assays

Cat-scratch disease (CSD), caused primarily by Bartonella henselae, is a common etiology of infectious regional lymphadenopathy. Lymphadenopathy is preceded by a primary inoculation lesion and may progress to suppuration. Laboratory diagnosis of CSD is hampered by the limitations of available confirmatory tests. PCR, in general, is highly sensitive and specific; however, clinical sensitivity in CSD varies greatly between studies. We aimed to identify clinical specimens and PCR assays best suited for CSD diagnosis using a national CSD registry and a uniform case definition. Different clinical specimens and PCR assays, including conventional and real-time PCR, were evaluated. PCR was positive in 335/390 (86%) CSD patients and 425/482 (88%) PCR tests. The highest PCR sensitivity was achieved in lymph node pus aspirates (96%; n = 278 tests) followed by primary lesions (88%; n = 50), lymph node fine needle aspirations (85%; n = 46), lymph node biopsy specimens (73%; n = 91) and paraffin-embedded lymph nodes (59%; n = 17), (P < 0.001). Sensitivity was similar in all types of PCR assays studied. PCR negative predictive value of pus aspirate and lymph node biopsy specimen patient groups was 82% and 72%, respectively. Specificity was 100% based on 125 non-CSD patients with negative PCR. In conclusion, the specimen type rather than the PCR assay type has a major impact on CSD molecular diagnosis. We assume that the inadequate sensitivity of the biopsy specimens was due to sampling errors or the presence of inhibitory factors. Primary lesions should be sampled more frequently for CSD diagnosis. Physicians should be aware of the low PCR negative predictive value of lymph node biopsy specimens. IMPORTANCE Polymerase chain reaction (PCR) for the detection of Bartonella henselae is an important tool for the diagnosis of cat scratch disease (CSD); however, clinical sensitivity varies greatly between studies. The current study shows that the specimen type, with pus aspiration, fine needle aspiration, and primary inoculation lesion having significantly higher sensitivity than fresh or formalin-fixed paraffin-embedded lymph node biopsy specimen, rather than the type of the PCR assay, whether a conventional or a real-time assay, has a major impact on the performance of diagnostic PCR for CSD. The new data provide new tools for the clinical microbiologist when interpreting the results of the PCR assays. Primary inoculation lesions, although easily accessible, are often neglected and should be sampled more frequently for molecular diagnosis of CSD. Physicians should be aware that negative PCR, particularly if performed on fresh or paraffin-embedded lymph node biopsy specimens, does not exclude CSD.

Misleading Positive Serology for Cat Scratch Disease Following Administration of Intravenous Immunoglobulin

Cat scratch disease (CSD), caused by Bartonella henselae, usually presents as regional lymphadenopathy/lymphadenitis, known as typical CSD or as atypical CSD, which includes, among others, neurological manifestations. Serology for anti-B. henselae IgG antibodies is the most commonly used diagnostic tests for CSD. Intravenous immunoglobulin (IVIG) is given for an increasing number of medical conditions and may cause interference with serological testing. We report six patients with neurological manifestations and two patients with Kawasaki disease mimicking typical CSD, mistakenly diagnosed as CSD due to false-positive serology following IVIG therapy. Bartonella IgG serology was positive one to six days after IVIG administration and reverted to negative in seven of eight patients or significantly decreased (1 patient) ≤30 days later. In patients with CSD, IgG titers remained essentially unchanged 15–78 days after the positive serum sample. An additional eight patients treated with IVIG for various conditions were evaluated prospectively. All were seronegative one day pre-IVIG infusion, five patients demonstrated an increase in the IgG titers one to three days after IVIG administration, one interpreted as positive and four as intermediate, whereas three patients remained seronegative, suggesting that false seropositivity after IVIG therapy may not occur in all patients. Treatment with IVIG can result in false-positive serology for B. henselae. Increased awareness to the misleading impact of IVIG is warranted to avoid misinterpretation. Repeat testing can distinguish between true and false serology. Preserving serum samples prior to IVIG administration is suggested.

Atlantoaxial instability secondary to Bartonella henselae osteomyelitis managed surgically by atlantoaxial instrumentation: A case report and systematic review

Cat scratch disease (CSD), caused by Bartonella henselae, may atypically present with vertebral osteomyelitis. Antibiotic regimens are tailored to presentation, which is markedly variable and not well defined for any atypical disease. In cases of spinal instability, the use of antibiotics alone may not be sufficient. Atlantoaxial instability caused by osteomyelitis is a rare complication of CSD. In this report, we describe the rare case of vertebral osteomyelitis complicated by atlantoaxial instability, requiring both antibiotics and atlantoaxial fusion. We discuss our case, surgical technique, rationale, and outcome. In addition, we conducted a systematic review of the literature of vertebral osteomyelitis in pediatric secondary to B. henselae. A 2-year-old child presented with a 2-month history of irritability, fever, and rigid neck pain along with a recent history of feline exposure. Physical examination revealed cervical tenderness and decreased range of motion. Computed tomography (CT) showed osteolysis of the right C1 lateral mass and pars articularis; T1-weighted magnetic resonance imaging with contrast showed enhancement around the right C1 lateral mass. The titer for B. henselae was high. A diagnosis of cat scratch osteomyelitis with cervical instability was made, for which the patient underwent surgery with atlantoaxial fusion. Postoperative imaging demonstrated resolution of the contrast-enhanced lesion. At 6-year follow-up, the patient showed no signs of residual complications from surgical intervention with a solid fusion. Our review revealed 44 cases of pediatric CSD vertebral osteomyelitis. Conservative management with antibiotic employed in 86% while antibiotics with surgical intervention in 14% of the cases. Surgical intervention was most often in the form of incision for drainage and decompression without fusion. Average follow-up 10 months with 86% achieved complete resolution. Cervical instability caused by osteolysis is a rare complication of CSD. This can subsequently lead to vertebral instability, requiring definitive surgical intervention.

Detection of antibodies against three zoonotic Bartonella spp. and cross-reactivity among species and Coxiella burnetii in dogs and cats from Central Thailand

Dogs and cats are important reservoir hosts of bacterial zoonotic pathogens, especially the Proteobacteria, Bartonella spp., and Coxiella burnetii. Bartonella spp. and C. burnetii are Gram-negative intracellular bacteria causing cat-scratch disease and query fever, respectively. Despite these two pathogens being dangerous, studies of their seroprevalence and cross-reactivity are limited in Thailand. The objectives of this study were to detect the seroprevalence of three zoonotic species of Bartonella and to evaluate cross-reactivity among Bartonella spp. and with C. burnetii. In total, 570 dog and cat serum samples were detected for antibodies against Bartonella spp. and C. burnetii using an indirect immunofluorescence antibody (IFA) test. At titer ≥ 1:64, tested serum that had a fluorescent intensity score ≥ 2 was interpreted as positive. Additionally, possible factors related to the seroprevalence were analyzed consisting of sex, breed, age, residing area, and ectoparasite control. Overall, the seroprevalence levels of Bartonella spp. and C. burnetii were 13.16% and 1.23%, respectively. All antigens of Bartonella were reacted to sera (1.23-7.72%), furthermore, both phases of C. burnetii were revealed in sera (0.35-1.05%). Interestingly, there was a poor agreement of cross-reactivity among Bartonella spp. at 5.56-8.70%, while cross-reactivity between Bartonella spp. and C. burnetii also showed poor agreement (2.80%). It is suggested that dogs and cats are important reservoirs of Bartonella spp., even in animals with ectoparasite control. The Bartonella seroprevalence was high in pure-breed animals with ectoparasite control, reflecting that Bartonella spp. infections can occur in owned, well-cared-for, and asymptomatic dogs and cats.

A CASE OF CAT SCRATCH DISEASE DIAGNOSED BY INDIRECT FLUORESCENT ANTIBODY ASSAY OF IgM SPECIFIC FOR A JAPANESE STRAIN OF Bartonella henselae

PURPOSE

To report a case of cat scratch disease-associated retinitis diagnosed with an indirect fluorescent antibody (IFA) assay for immunoglobulin M (IgM) specific for a strain (YH-01) of Bartonella henselae recently identified in Japan.

METHODS

Case report of a 24-year-old pregnant woman presented with general fever, fatigue, as well as blurred vision, and a central visual field deficiency in her right eye and was suspected as cat scratch disease because she had started to feed a feral dog a month ago.

RESULTS

The patient's serum tested negative, however, with an IFA assay for IgG or IgM specific for the Houston-1, common strain of B. henselae. Further testing with an IFA assay for IgM specific for the YH-01 strain yielded a positive result. On the basis of the clinical findings and the IFA results, we were thus able to make a definitive diagnosis of cat scratch disease.

CONCLUSION

An IFA assay based on the YH-01 or combination of both YH-01 and Houston-1 strains of B. henselae may show increased sensitivity for the diagnosis of cat scratch disease in Japan.

Comparison of Serological and Molecular Assays for Bartonella Species in Dogs with Hemangiosarcoma

Currently, a gold standard diagnostic test for Bartonella infection in dogs is lacking. This represents a critical limitation for the development and evaluation of new diagnostic tests, as well as for the diagnosis of, and research on, bartonellosis in dogs. This retrospective observational study aims to compare the results of commonly performed and newly-reported Bartonella spp. diagnostic tests in banked clinical specimens from 90 dogs with hemangiosarcoma (HSA) using composite reference standard (CRS) and random effects latent class analysis (RE-LCA) techniques. Samples from each dog were tested using six serological or molecular diagnostic assays, including indirect fluorescent antibody (IFA) and Western blot (WB) for the detection of antibodies in serum, and qPCR and droplet digital PCR (ddPCR) in blood and fresh frozen tissue biopsy samples (mainly splenic HSA tumors and histopathologically normal spleen or skin/adipose tissue). Bartonella infection prevalence was estimated to be 78% based on the CRS (parallel testing with all six assays), and 64% based on the RE-LCA model. The assay with the highest diagnostic accuracy was qPCR performed on fresh frozen tissue biopsy samples (sensitivity: 94% by RE-LCA and 80% by CRS; specificity: 100%). When comparing newly-reported to traditional Bartonella diagnostic assays, ddPCR was more sensitive for the detection of Bartonella DNA than qPCR when testing blood samples (36% vs. 0%, p < 0.0001). Dogs that were positive on serological assays alone with negative molecular assays were highly unlikely (<3%) to be classified as infected by the RE-LCA model. These data indicate that Bartonella spp. DNA can be PCR amplified from fresh frozen tissues from a majority of dogs with HSA using both qPCR and ddPCR, supporting the use of these methods for future controlled studies comparing the prevalence of Bartonella spp. DNA in the tissue of dogs with HSA to that of unaffected controls.

Schizophrenia and Bartonella spp. Infection: A Pilot Case-Control Study

Recently, infections with emerging zoonotic bacteria of the genus Bartonella have been reported in association with a range of central nervous system (CNS) symptoms. Currently, it remains unknown if Bartonella spp. infection is associated with symptoms of schizophrenia/schizoaffective disorder (SCZ/SAD). The objective of this study was to determine if there is an association between Bartonella species infection and SCZ/SAD. A secondary objective was to determine if SCZ/SAD symptoms were more severe among participants with documented Bartonella spp. infection. Using a case-control study design, 17 cases and 13 controls were evaluated with a series of clinical and cognitive assessments. Blood samples were collected and tested for Bartonella spp. infection using serological, microbiological, and molecular techniques. People with SCZ/SAD were more likely than healthy volunteers to have Bartonella spp. DNA in their bloodstream, with 11 of 17 cases (65%) positive by Bartonella spp. droplet digital PCR (ddPCR). In comparison, only one healthy volunteer was Bartonella spp. ddPCR positive (8%, p = 0.0024). Based on serology, Bartonella spp. exposure was common among people with SCZ/SAD (12 of 17) as well as among healthy volunteers (12 of 13), with no significant difference between the groups (p = 0.196). Within the case group of people with SCZ/SAD, there was no significant difference in SCZ/SAD severity scores between people with and without ddPCR evidence of Bartonella spp. infection. This pilot study provides preliminary evidence in support of future investigations that should examine a potential contribution of Bartonella spp. infection to SCZ/SAD.

Zoonotic Rickettsia Species in Small Ruminant Ticks From Tunisia

Tick-borne rickettsioses present a significant public health threat among emerging tick-borne diseases. In Tunisia, little is known about tick-borne Rickettsia pathogens. Therefore, the aim of this study was to investigate the presence of Rickettsia species in small ruminant ticks from Tunisia. Adult ticks (n = 694) were collected from goats and sheep in northern Tunisia. Obtained ticks were identified as Rhipicephalus turanicus (n = 434) and Rhipicephalus sanguineus sensu lato (n = 260). Selected ticks (n = 666) were screened for the presence of Rickettsia spp. by PCR targeting a partial sequence of the ompB gene followed by sequence analysis. Rickettsial DNA was detected in 122 (18.3%) tested tick samples. The infection rates in Rh. turanicus and Rh. sanguineus s.l. ticks were 23.4 and 9.5%, respectively. The overall prevalence of rickettsial DNA was markedly higher in ticks collected from goats (23.2%) compared to those infesting sheep (7.9%). The detection of rickettsial DNA was significantly higher in ticks from the governorate of Beja (39.0%) than those from the governorate of Bizerte (13.9%). Two additional genes, the outer membrane protein A gene (ompA) and the citrate synthase gene (gltA), were also targeted for further characterization of the detected Rickettsia species. Genotyping and phylogenetic analysis based on partial sequences (n = 106) of the three different genes revealed that positive ticks are infected with different isolates of two Spotted Fever Group (SFG) Rickettsia, namely, Rickettsia massiliae and Rickettsia monacensis, closely related to those infecting camels and associated ticks from Tunisia, and humans and small ruminant ticks from neighboring countries like Italy, France, and Spain.

Laboratory Diagnosis of 37 Cases of Bartonella Endocarditis Based on Enzyme Immunoassay and Real-Time PCR

Bartonella spp., mostly Bartonella quintana and B. henselae, are a common cause of culture-negative endocarditis. Serology using immunofluorescence assay (IFA) and PCR performed on cardiac tissues are the mainstays of diagnosis. We developed an enzyme immunoassay (EIA) and a novel multiplex real-time PCR assay, utilizing Bartonella genus-specific, B. henselae-specific, and B. quintana-specific SimpleProbe probes, for diagnosis of Bartonella endocarditis. We aimed to evaluate the performance of these assays. Thirty-seven patients with definite endocarditis, 18 with B. henselae, 18 with B. quintana, and 1 with B. koehlerae, were studied. Diagnosis was confirmed by conventional PCR and DNA sequencing of surgical cardiac specimens. Similar to the case with IFA, anti-Bartonella IgG titers of ≥1:800 were found in 94% of patients by EIA; cross-reactivity between B. henselae and B. quintana precluded species-specific serodiagnosis, and frequent (41%) but low-titer cross-reactivity between Coxiella burnetii antibodies and B. henselae antigen was found in patients with Q fever endocarditis. Low-titer (1:100) cross-reactivity was uncommonly found also in patients with brucellosis and culture-positive endocarditis, particularly Enterococcus faecalis endocarditis. Real-time PCR performed on explanted heart valves/vegetations was in complete agreement with results of sequence-based diagnosis with characteristic melting curves. The genus-specific probe identified five additional endocarditis-associated Bartonella spp. at the genus level. In conclusion, EIA coupled with a novel real-time PCR assay can play an important role in Bartonella endocarditis diagnosis and expand the diagnostic arsenal at the disposal of the clinical microbiologist. Since serology remains a major diagnostic tool, recognizing its pitfalls is essential to avoid incorrect diagnosis.

Cat Scratch Disease and Bartonellaceae: The Known, the Unknown and the Curious

Since the early 1900s, Bartonella species were known only to cause human disease resulting from very restricted geographic (bartonellosis) or environmental influences ("trench fever"). In the 1990s, and in parallel, cat scratch disease and bacillary angiomatosis were definitively linked to Bartonella species. Subsequently, widespread use of modern diagnostic methods revealed the broad ecologic niche of this organism and greatly expanded our knowledge of the epidemiology and clinical presentations associated with this genus. A large number of reservoirs and vectors involved with Bartonella propagation and transmission to humans have been identified; cats and various arthropods remain the most well-studied to date. Though not completely understood, it appears that specific immune-modulated interactions between the infecting species and host-related factors play a major role in the observed breadth of human clinical syndromes associated with Bartonellae, the large differences in immunopathologic features of tissue samples among different syndromes and potentially the varied responses to antimicrobial therapy. Further, the clinical management for cat scratch disease in particular is quite variable among clinicians, reflecting a poor evidence base. No preventive measures have been developed beyond suggestions to avoid at-risk behavior with known vectors.

Ectoparasites of hedgehogs: From flea mite phoresy to their role as vectors of pathogens

Hedgehogs are synanthropic mammals, reservoirs of several vector-borne pathogens and hosts of ectoparasites. Arthropod-borne pathogens (i.e., Rickettsia spp., Borrelia spp., and Anaplasmataceae) were molecularly investigated in ectoparasites collected on hedgehogs (n = 213) from Iran (161 Hemiechinus auritus, 5 Erinaceus concolor) and Italy (47 Erinaceus europaeus). In Iran, most animals examined (n = 153; 92.2%) were infested by ticks (Rhipicephalus turanicus, Hyalomma dromedarii), and 7 (4.2%) by fleas (Archeopsylla erinacei, Ctenocephalides felis). Of the hedgehogs infested by arthropods in Italy (i.e., 44.7%), 18 (38.3%) were infested by fleas (Ar. erinacei), 7 (14.9%) by ticks (Haemaphysalis erinacei, Rh. turanicus, Rhipicephalus sanguineus sensu lato), and 6 (12.8%) by mites (Caparinia tripilis, Acarus nidicolous, Ornithonyssus spp.). Phoretic behavior of C. tripilis on Ar. erinacei was detected in two flea specimens from Italy. At the molecular analysis Rickettsia spp. was detected in 93.3% of the fleas of Italy. In Iran, Rickettsia spp. was detected in 8.0% out of 212 Rh. turanicus ticks, and in 85.7% of the Ar. erinacei fleas examined. The 16S rRNA gene for Ehrlichia/Anaplasma spp. was amplified in 4.2% of the 212 Rh. turanicus ticks. All sequences of Rickettsia spp. from fleas presented 100% nucleotide identity with Rickettsia asembonensis, whereas Rickettsia spp. from Rh. turanicus presented 99.84%–100% nucleotide identity with Rickettsia slovaca, except for one sequence, identical to Rickettsia massiliae. The sequences of the 16S rRNA gene revealed 99.57%–100% nucleotide identity with Anaplasma spp., except for one, identical to Ehrlichia spp. A new phoretic association between C. tripilis mites and Ar. erinacei fleas has been herein reported, which could be an important route for the spreading of this mite through hedgehog populations. Additionally, spotted fever group rickettsiae were herein detected in ticks and fleas, and Anaplasma/Ehrlichia spp. in ticks, suggesting that hedgehogs play a role as reservoirs for these vector-borne pathogens.

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New phoretic association of Caparinia tripilis mites on Archaeopsylla erinacei fleas.

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Occurrence of spotted fever group rickettsiae in Rhipicephalus turanicus from hedgehogs.

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Occurrence of Anaplasmataceae in Rhipicephalus turanicus from hedgehogs.

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High Prevalence of Rickettsia asembonensis in Archaeopsylla erinacei fleas from hedgehogs.

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Hedgehogs are suggested as reservoirs of vector-borne pathogens.

Clinical Manifestations Associated with Bartonella henselae Infection in a Tropical Region

Bartonella henselae is a zoonotic Gram-negative Bacillus associated with self-limited regional lymphadenopathy. In recent decades, an expanding spectrum of clinical manifestations has been described, in part, due to improved diagnostics. However, updated epidemiological data are sparse. We retrospectively reviewed the clinical features of 31 patients with B. henselae infection over 15 years from 2005 to 2019, in the tropical Top End of Australia. Our annual disease incidence of 1.3 cases per 100,000 population is lower than that in the national database surveillances in the United States, but the hospitalization incidence of 0.9 per 100,000 population in our region is higher than those reported in the literature, with an average length of stay of 9 days. Patients were more commonly male, aboriginal, and aged less than 14 years (median age: 7 years), living in a rural setting with presentation during our monsoon season. The disease spectrum included lymph node disease (74%), organ peliosis, endocarditis, cutaneous lesions, parapharyngeal abscess, parotitis, and neurologic and ocular syndromes. Lymph node disease was far commoner in children than the more serious systemic B. henselae infections associated with adults (P = 0.074). Although no deaths were reported, significant morbidities were observed. Two endocarditis cases presented with glomerulonephritis, and hematological and neurological features mimicking vasculitis, and consequently received immunosuppressants. One case was only diagnosed after representation with serial embolic strokes. Given the heterogeneity of disease manifestations with nonspecific symptoms and significant consequences, a timely and accurate diagnosis is needed to avoid unnecessary treatments or interventions.

Cat Scratch Disease: The First Case Report in Republic of North Macedonia

Cat scratch disease (CSD) is the main clinical manifestation caused by Bartonella henselae in immuno-competent patients. The bacterium is transmitted to humans from cats via scratches or bites. In this case report, we are presenting to our knowledge the first etiologically confirmed case of CSD in our country. Here we describe the case of a previously healthy adult female patient presenting with fever and axillar lymphadenopathy over 1-month period. She underwent numerous clinical and paraclinical investigations for potential etiologies associated with lymphadenopathy and fever. Finally, serological testing for B.henselae was performed with titers for IgG 1:1024 and 1:160 for IgM, which confirmed the diagnosis. Five-day treatment with azithromycin resulted with good clinical response and complete recovery. We proved that CSD is a reality in our country and this report should raise awareness in medical doctors, especially infectious disease specialist. Also, CSD should be included in differential diagnosis in patients with fever of unkown origin (FUO), who are presenting with regional lymphadenopathy, with or without history of cat contact.

Analytical and clinical evaluation of new automated chemiluminescent immunoassays for the detection of IgG and IgM anti-Bartonella henselae antibodies

Serological diagnosis of Bartonella henselae infection mainly rely on microscopic immunofluorescence assays (IFA), which are however time-consuming and poorly standardized. The aim of the study was to assess the use of the new fully automated VirClia® chemiluminescent immunoassays for the detection of IgG and IgM anti-B. henselae antibodies. Eighty-one patients with a well-defined B. henselae infection as well as 80 patients with an alternative disease were included. The VirClia® IgG antibody assay showed a sensitivity of 79.0% and a specificity of 93.8% for the diagnosis of B. henselae infection. For the VirClia® IgM assay, results were more conflicting with a sensitivity of 42.0% and a specificity of 98.2% to predict IFA IgM results. In 11 additional patients with uninterpretable IFA due to autoimmune antibodies, VirClia® assays were able to deliver valuable quantitative results. The VirClia® IgG assay shows good analytical and clinical performances and could be easily integrated in the diagnostic workflow of B. henselae infection.

A non-coding RNA controls transcription of a gene encoding a DNA binding protein that modulates biofilm development in Bartonella henselae

Bartonella henselae (Bh) is a Gram-negative zoonotic bacterium that can grow as large aggregates and form biofilms in vitro dependent upon the adhesin BadA. Previously, we reported that the Houston-1 strain of Bh has a family of nine small, highly-expressed intergenic transcripts called Bartonellaregulatory transcripts, Brt1-9. Each of the Brts bears a stem and loop structure on the 3' end followed by a gene encoding a DNA binding protein called the Transcriptional regulatory proteins, Trp1-9. RNA-seq analysis of laboratory-grown bacteria revealed the trps were poorly transcribed suggesting that the 3' stem and loop on the Brts results in transcript termination upstream of the trp genes under these conditions. Here we demonstrate that transcription of brt1 continues into trp1 when Bh is grown in a biofilm. Deletion of brt1, or just the 3' terminus of brt1 (containing the stem and loop structure), resulted in increased transcription of both trp1 and badA and increased biofilm formation. Trp1 was shown to directly bind the putative badA promoter region as demonstrated by an electrophoretic mobility shift assay (EMSA). Our data suggest that the 3' end of brt1 responds to a stimulus generated by growth of Bh in an in vitro biofilm to allow increased trp1 transcription. We further show that transcription of trp1 increases under conditions consistent with the mammalian host but is not highly expressed in the cat flea vector until the bacterium is excreted into the flea feces. Based on these data, we hypothesize that the 3' end of Brt1 functions to control trp1 transcription and Trp1 in turn results in increased badA expression and enhanced biofilm formation.

Ocular complications of cat scratch disease

Cat scratch disease (CSD) in humans is caused by infection with Bartonella henselae or other Bartonella spp. The name of the disease reflects the fact that patients frequently have a history of contact (often involving bites or scratches) with infected cats. Patients with CSD typically develop lesions at the site where the skin is broken together with regional lymphadenopathy but may go on to exhibit systemic symptoms and with deep-seated infections at a range of sites including the eye. Patients with CSD may present with a range of inflammatory eye conditions, including Parinaud's oculoglandular syndrome, neuroretinitis, multifocal retinitis, uveitis and retinal artery occlusion. Bartonella spp. are fastidious bacteria that are difficult to culture from clinical specimens so microbiological diagnosis is frequently made on the basis of positive serology for anti-Bartonella antibodies or detection of bacterial DNA by PCR. Due to the lack of clinical trials, the evidence base for optimal management of patients with CSD-associated eye infections (including the role of antibiotics) is weak, being derived from single reports or small, uncontrolled case series.

Typical and Atypical 18FDG PET/CT Findings in Two Cases of Cat Scratch Disease

Cat scratch disease (CSD) is a rare zoonotic infection disease, and the imaging performance for evaluation varies. We present FDG PET/CT images of two cases of CSD. In one case, images showed typical findings of regional lymph node enlargement. In another case, images showed atypical findings of extensive superficial and deep lymph node enlargement.

Bartonella henselae DNA in Seronegative Patients with Cat-Scratch Disease

We used real-time PCR to detect Bartonella henselae DNA in 7.9% (5/63) of blood specimens from seronegative patients in Japan suspected of having cat-scratch disease. The combined use of serologic tests and real-time PCR to analyze blood specimens is recommended for the prompt, noninvasive laboratory diagnosis of cat-scratch disease.

Development of a Specific and Sensitive Enzyme-Linked Immunosorbent Assay as an In Vitro Diagnostic Tool for Detection of Bartonella henselae Antibodies in Human Serum

Bartonella henselae causes cat scratch disease and several other clinical entities. Infections with B. henselae are frequently occurring; however, the infection is only rarely diagnosed, mainly due to a lack of knowledge in the medical community. Microscopic immunofluorescence assays (IFA) are widely used for the serodiagnosis of B. henselae infections but are laborious and time-consuming, and interpretation is subjective. An easy and reliable method for the serological diagnosis of B. henselae infections is needed to overcome the shortcomings of the current IFA. Here, we report the development of an ELISA detecting human anti-B. henselae antibodies from serum samples. By separating the water-insoluble fraction of B. henselae Houston-1 via ion-exchange chromatography, 16 subfractions were generated and tested for immunoreactivity via line blotting. One particular fraction (fraction 24) was selected and spotted on ELISA plates using an industrial production platform. By use of well-characterized human sera from the strictly quality-controlled serum library of the German National Consiliary Laboratory for Bartonella infections, the sensitivity of this ELISA was 100% for PCR-proven infections and 76% for clinically suspected infections at a specificity of 93%. This ELISA is therefore a reliable high-throughput method allowing the serodiagnosis of B. henselae infections.

Cat-Scratch Disease in an AIDS Patient Presenting with Generalized Lymphadenopathy: An Unusual Presentation with Delayed Diagnosis

Patient: Female, 44

Final Diagnosis: Cat-scratch disease

Symptoms: Lymfadenopathy

Medication: —

Clinical Procedure: Lymph node biopsy

Specialty: Infectious Diseases

Bartonella henselae infection presenting as cervical spine osteomyelitis: case report

Bartonella henselae is a gram-negative bacillus implicated in cat-scratch disease. Cat-scratch disease is usually self-limiting and results in local lymphadenopathy. In rare circumstances, patients may develop endocarditis, neuroretinitis, or osteomyelitis. Osteomyelitis of the cervical spine is exceedingly rare, especially in the pediatric population, and to date there have been only 4 previously reported cases of cervical spine osteomyelitis caused by B. henselae, all of which were treated surgically. In this article, the authors report the case of a 7-year-old boy who presented with neck swelling and was found to have a C2-4 paravertebral B. henselae abscess with osteomyelitis of C-3 and epidural extension. To the authors' knowledge, this represents the first case in the literature of a cervical spine B. henselae infection managed conservatively.

Lymphadenitis associated with cat-scratch disease simulating a neoplasm: Imaging findings with histopathological associations

The lymphadenitis associated with cat-scratch disease (CSD) is often confused with neoplasms by a number of radiologists and clinicians, and consequently, unnecessary invasive procedures or surgeries are performed. In the present study, the contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) findings of 10 patients (6 men and 4 women) with clinically and pathologically confirmed lymphadenitis associated with CSD were retrospectively analyzed (CT in 3 patients, MRI in 6 patients, and CT and MRI in 1 patient) at The Second Affiliated Hospital of Zhejiang University School of Medicine (Hangzhou, China) between January 2007 and November 2014. As a result, 17 enlarged lymph nodes were identified in 10 cases. The 5 nodes identified by CT scan exhibited relatively inhomogeneous isodensity to muscle, with patchy low density in the center. All 14 nodes identified by MRI scan exhibited homogeneous or heterogeneous isointensity to muscle or slightly increased intensity compared with that of muscle on T1-weighted images (T1WI), and homogeneous or heterogeneous hyperintensity on fat-suppressed T2WI. Following enhancement, all 17 enlarged lymph nodes associated with CSD demonstrated the following 3 different enhancement patterns: Moderate homogeneous enhancement (n=8), which was associated with histologically identified early disease stage; marked heterogeneous enhancement with no enhancement of the necrotic areas (n=4), and heterogeneous enhancement with progressively ‘spoke-wheel-like’ (defined as radiating enhancement from the center) enhancement of the patchy low-density area (n=1), which was associated with histologically identified intermediate disease stage; and astral low-density/hypointensity with marked enhancement (n=2) or a ‘rose flower’ sign (n=2), which was associated with histologically identified late disease stage. We hypothesized that the CT and MRI results of lymphadenitis in CSD may be associated with the pathological features. It may be suggested that the diagnosis of CSD may be formed when considering the characteristic CT and MRI features of astral low-density/hypointensity with marked enhancement or a ‘rose flower’ sign (defined as marginal petaloid enhancement) in the late disease stage, or the MRI results of homogeneous, moderate enhancement in the early disease stage, or the CT/MRI data of heterogeneous enhancement with non-enhancing area in the center in the intermediate disease stage, in solitary or multiple enlarged lymph nodes associated with general subcutaneous edema in the vicinity of the nodes on CT/MRI and with a history of cat exposure.

Utility of Bartonella henselae IgM Western Blot Bands for Serodiagnosis of Cat Scratch Disease

We evaluated the utility of Western blot (WB) bands of Bartonella henselae in detecting anti-B. henselae immunoglobulin M (IgM) for serodiagnosis of cat scratch disease (CSD). IgM band patterns were examined using sera from 92 patients clinically suspected of having CSD and from 130 healthy individuals. Positive WB bands were observed in 49 (53.5%) of the 92 patient sera. Three bands at 8 to 10, 31 to 35, and 70 kDa were regarded as relevant for B. henselae because all of the positive sera yielded at least one of the three bands, and none of the healthy control sera showed reactivity to any of them. In contrast, the positive rate of the patient sera by conventional indirect fluorescence antibody assay (IFA) for B. henselae IgM was 28.3% (26/92) among the patients. These finding suggest that the IgM-WB assay, although cumbersome to perform, can be used for confirmatory diagnosis of CSD with no false positivity in the control sera. Purification of proteins in the specific bands may contribute to the development of an IgM enzyme-linked immunosorbent assay (IgM-ELISA) with improved specificity and sensitivity.

Bartonella Species, an Emerging Cause of Blood-Culture-Negative Endocarditis

Since the reclassification of the genus Bartonella in 1993, the number of species has grown from 1 to 45 currently designated members. Likewise, the association of different Bartonella species with human disease continues to grow, as does the range of clinical presentations associated with these bacteria. Among these, blood-culture-negative endocarditis stands out as a common, often undiagnosed, clinical presentation of infection with several different Bartonella species. The limitations of laboratory tests resulting in this underdiagnosis of Bartonella endocarditis are discussed. The varied clinical picture of Bartonella infection and a review of clinical aspects of endocarditis caused by Bartonella are presented. We also summarize the current knowledge of the molecular basis of Bartonella pathogenesis, focusing on surface adhesins in the two Bartonella species that most commonly cause endocarditis, B. henselae and B. quintana. We discuss evidence that surface adhesins are important factors for autoaggregation and biofilm formation by Bartonella species. Finally, we propose that biofilm formation is a critical step in the formation of vegetative masses during Bartonella-mediated endocarditis and represents a potential reservoir for persistence by these bacteria.

Bartonella henselae is usually not viable in lymph nodes of patients with cat scratch disease

Bartonella henselae, the agent of cat scratch disease (CSD), appears to be a common organism responsible for lymphadenitis in both adults and children. There is a very low isolation rate for B. henselae from lymph nodes of patients with CSD. Our objective was to evaluate B. henselae viability in a large series of lymph nodes from patients with CSD. From January to November 2016, we analyzed lymph node biopsy samples from patients diagnosed with CSD. We used reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to detect B. henselae RNA, as well as cultures, histological analyses, and fluorescence in situ hybridization (FISH). We tested 87 lymph nodes positive for B. henselae DNA but only 8 (9%) presented with B. henselae RNA. We did not find a significant difference for the pap threshold cycle (C_T) values between RNA-positive and RNA-negative lymph nodes (p = 0.5). Cultures, histological analyses, and FISH were negative for all the tested samples. We provide evidence that B. henselae are not or are rarely viable in most cases in the lymph nodes of patients with CSD.

Disseminated cat-scratch disease presenting as nausea, diarrhea, and weight loss without fever in a heart transplant recipient

We report the case of an afebrile 59-year-old heart transplant recipient presenting with nausea, vomiting, diarrhea, weight loss, and diffuse lymphadenopathy. Lymph node biopsies revealed non-caseating granulomatous inflammation. Cat-scratch disease was confirmed by serologic studies, Warthin-Starry staining, and polymerase chain reaction testing of lymph node tissue. The patient's symptoms resolved with 3 months of doxycycline. We review clinical presentations of Bartonella henselae infection and review diagnostic approaches for B. henselae in this patient population.

Cat-Scratch Disease: Case Report and Review of the Literature

Cat-scratch disease (CSD) is caused by Bartonella henselae and characterized by self-limited fever and granulomatous lymphadenopathy. In some cases signs of a visceral, neurologic, and ocular involvement can also be encountered. In this report we describe the development of CSD in a kidney transplant patient. Immunocompromised hosts are more susceptible to infection from Bartonella compared with the standard population. Infection of Bartonella should be considered as a differential diagnosis in kidney transplant patients with lymphadenopathy of unknown origin.

Cat-scratch disease: Otolaryngologic manifestations and management

OBJECTIVE:

The bacteria Bartonella henselae has been known as the principal causative agent of cat-scratch disease (CSD) since 1992. It is an important cause of infectious lymphadenopathies in the head and neck. Nevertheless, CSD often remains unrecognized in cases of cervicofacial lymph node enlargement.

STUDY DESIGN:

Between January 1997 and May 2003, we conducted a prospective clinical study including 721 patients with primarily unclear masses in the head and neck.

RESULTS:

CSD was diagnosed by serology and molecular investigations in 99 patients (13.7%; median age 33 years). Cervicofacial lymphadenopathy was the most common manifestation. Atypical manifestation of CSD including Parinaud's oculoglandular syndrome, swelling of the parotid gland and erythema nodosum were diagnosed in 8.1%, 8.1%, and 2.0% of cases, respectively.

CONCLUSIONS:

Our results demonstrate that CSD is a major cause of enlarged cervicofacial lymph nodes and should therefore be included in the differential diagnosis of lymphadenopathy in the head and neck region.

[Eye and cat scratch disease: A case series]

INTRODUCTION

Cat scratch disease is a pleiomorphic condition, sometimes with isolated ophthalmic involvement. We report the clinical observations of seven cases with ophthalmologic manifestations of cat scratch disease.

OBSERVATIONS

There were seven patients, with a median age of 52 years, of whom five were women and three had unilateral involvement. Six exhibited Leber's stellate neuroretinitis, an incomplete syndrome in two cases, and one associated with chorioretinal foci. One patient had isolated retinal infiltrates. The diagnosis of cat scratch disease was confirmed by Bartonella henselae serology, positive in all cases. All patients received treatment with doxycycline. Ocular complications (with optic atrophy and macular retinal pigment epithelial changes) were noted in five cases.

DISCUSSION

Ocular bartonellosis is an atypical clinical form. It requires a directed ancillary work-up with serology or PCR, which has the peculiarity of being highly specific if not very sensitive. Treatment is above all preventive. Antibiotics may be initiated.

CONCLUSION

Cat scratch disease must be excluded in the work-up of posterior uveitis.

Development of a Highly Specific IgM Enzyme-Linked Immunosorbent Assay for Bartonella henselae Using Refined N-Lauroyl-Sarcosine-Insoluble Proteins for Serodiagnosis of Cat Scratch Disease

The conventional anti-Bartonella henselaeIgM enzyme-linked immunosorbent assay (IgM-ELISA) methods for diagnosing cat scratch disease (CSD) remain poor in both sensitivity and specificity. We sought to develop an IgM-ELISA with improved accuracy in the serodiagnosis of CSD by exploring the antigens that are most suitable for an ELISA. We prepared 5 different protein antigens: antigen I (sonicatedB. henselaewhole-cell antigen), antigen II (N-lauroyl-sarcosine-insoluble antigen), antigen III (processed sarcosine-soluble antigen), and antigen IV and antigen V (sarcosine-insoluble and sarcosine-soluble antigens refined by DEAE-Sepharose Fast Flow ion-exchange chromatography). The IgM antibodies in the sera of 47 patients with clinically suspected CSD (24 definite, 23 suspected) and of 85 healthy individuals were examined by ELISAs using the 5 antigens, and the results were compared with those of an IgM indirect fluorescent antibody assay (IgM-IFA). In a reference panel, which consisted of 5 positive and 5 negative sera, antigen I and antigen III failed to distinguish between the two statuses, whereas the other three antigens succeeded in distinguishing between them. When the cutoff value was set at the 98th percentile of the ELISA index for healthy individuals, the sensitivity of IgM-IFA for the 24 cases of definite CSD was 54%, whereas the sensitivities of the IgM-ELISAs with antigen II, IV, and V were 75%, 83%, and 75%, respectively. The sensitivities of these three IgM-ELISAs for all 47 of the clinically suspected cases were 49%, 64%, and 51%, respectively. In contrast, the sensitivity of IgM-IFA was 28%. These results indicate that the refined sarcosine-insoluble proteins (antigen IV), which possessed the highest specificity among the 5 antigens, are the most appropriate for developing an IgM-ELISA for the highly specific serodiagnosis of CSD.

Cat-scratch disease with severe pleuritis in a 6-year-old girl

We present the case of a 6-year-old girl with cat-scratch disease (CSD), who developed severe pleuritis without lymphadenitis. Bartonella henselae DNA was detected on real-time polymerase chain reaction (PCR) analysis of whole blood. This is the first report of CSD diagnosed on real-time PCR using whole blood.

Bartonella henselae in eastern Poland: the relationship between tick infection rates and the serological response of individuals occupationally exposed to tick bites

To explore the potential role of Ixodes ricinus as the presumed vector of Bartonella henselae in eastern Poland, ticks collected in various geographic locations were examined for the presence of B. henselae, and the results were matched against the prevalence of anti-B. henselae antibodies in individuals occupationally exposed to tick bites. The presence of Bartonella DNA was investigated by PCR in a total of 1,603 unfed Ixodes ricinus ticks. The presence of IgG antibodies against B. henselae was investigated in serum samples from 332 people occupationally exposed to tick bites (94 farmers and 238 forestry workers). The total prevalence of B. henselae in ticks was 1.7%; the infection rates in males (3.1%) and females (2.7%) were nearly ten times greater than in nymphs (0.3%). The prevalence of seropositive results in the risk group (30.4%), farmers (27.7%) and forestry workers (31.5%), was significantly greater compared to the control group (8.9%). The results showed a weak positive correlation between the degree of infection of ticks and humans living in the same geographic region. The lack of a direct relationship indicates that exposure to tick bites is only one of the factors contributing to the significant preponderance of a seropositive response to B. henselae in the forestry workers and farmers over the control group. Other factors must be considered, such as contact with cats, which are popular domestic animals in Polish villages, and exposure to cat fleas.

Sonography of cat scratch disease

OBJECTIVES

To characterize the sonographic features of cat scratch disease and to identify features that allow differentiation from other causes of medial epitrochlear masses.

METHODS

After Institutional Review Board approval was obtained, patients who underwent sonography for a medial epitrochlear mass or lymph node were identified via the radiology information system. Patients were divided into 2 groups: cat scratch disease and non-cat scratch disease, based on pathologic results and clinical information. Sonograms were retrospectively reviewed and characterized with respect to dimension, shape (round, oval, or lobular), symmetry, location (subcutaneous or intramuscular), multiplicity, echogenicity (anechoic, hypoechoic, isoechoic, hyperechoic, or mixed), hyperechoic hilum (present or absent), adjacent anechoic or hypoechoic area, hyperemia (present or absent), pattern of hyperemia if present (central, peripheral, or mixed), increased posterior through-transmission (present or absent), and shadowing (present or absent). Sonographic findings were compared between the patients with and without cat scratch disease.

RESULTS

The final patient group consisted of 5 cases of cat scratch disease and 16 cases of other causes of medial epitrochlear masses. The 2 sonographic findings that were significantly different between the cat scratch disease and non-cat scratch disease cases included mass asymmetry (P = .0062) and the presence of a hyperechoic hilum (P = .0075). The other sonographic findings showed no significant differences between the groups.

CONCLUSIONS

The sonographic finding of an epitrochlear mass due to cat scratch disease most commonly is that of a hypoechoic lobular or oval mass with central hyperemia and a possible adjacent fluid collection; however, the presence of asymmetry and a hyperechoic hilum differentiate cat scratch disease from other etiologies.

Possible infectious causes of spontaneous splenic rupture: a case report

Introduction

Spontaneous atraumatic splenic rupture is a rare but dramatic occurrence that is most commonly attributed to infection or neoplasia. Deciphering the etiology can be challenging with many cases remaining unclear despite full investigation.

Case presentation

We report the case of a previously healthy and immunocompetent 52-year-old Caucasian woman with a remote history of clinically diagnosed infectious mononucleosis who experienced sudden atraumatic splenic rupture after an untreated stray cat bite.

Conclusions

The differential diagnosis for atraumatic splenic rupture, specifically its infectious causes, is reviewed. Key clinical and laboratory findings that differentiate Bartonella henselae infection and Epstein–Barr virus reinfection are reviewed.