Evaluation of immunohistochemistry in identifying Bartonella henselae in cat-scratch disease

Detection of Bartonella henselae DNA in the blood of patients with livedoid vasculopathy

BACKGROUND

Livedoid vasculopathy (LV) manifests as ulcers and atrophic white scars on the lower extremities. The main known etiopathogenesis is hypercoagulability with thrombus formation, followed by inflammation. Thrombophilia, collagen and myeloproliferative diseases may induce LV, but the idiopathic (primary) form predominates. Bartonella sp. may cause intra-endothelial infection and skin manifestations caused by these bacteria may be diverse, including leukocytoclastic vasculitis and ulcers.

OBJECTIVE

The aim of this study was to investigate the presence of bacteremia by Bartonella spp. in patients with difficult-to-control chronic ulcers diagnosed as primary LV.

METHODS

Questionnaires and molecular tests (conventional PCR, nested PCR and real-time PCR) were applied and liquid and solid cultures were performed in the blood samples and blood clot of 16 LV patients and 32 healthy volunteers.

RESULTS

Bartonella henselae DNA was detected in 25% of LV patients and in 12.5% of control subjects but failed to reach statistically significant differences (p = 0.413).

STUDY LIMITATIONS

Due to the rarity of primary LV, the number of patients studied was small and there was greater exposure of the control group to risk factors for Bartonella spp.

INFECTION

CONCLUSION

Although there was no statistically significant difference between the groups, the DNA of B. henselae was detected in one of every four patients, which reinforces the need to investigate Bartonella spp. in patients with primary LV.

Contemporary diagnostics for medically relevant fastidious microorganisms belonging to the genera Anaplasma, Bartonella, Coxiella, Orientia, and Rickettsia

Many of the human infectious pathogens—especially the zoonotic or vector-borne bacteria—are fastidious organisms that are difficult to cultivate because of their strong adaption to the infected host culminating in their near-complete physiological dependence on this environment. These bacterial species exhibit reduced multiplication rates once they are removed from their optimal ecological niche. This fact complicates the laboratory diagnosis of the disease and hinders the detection and further characterization of the underlying organisms, e.g. at the level of their resistance to antibiotics due to their slow growth. Here, we describe the current state of microbiological diagnostics for five genera of human pathogens with a fastidious laboratory lifestyle. For Anaplasma spp., Bartonella spp., Coxiella burnetii, Orientia spp. and Rickettsia spp., we will summarize the existing diagnostic protocols, the specific limitations for implementation of novel diagnostic approaches and the need for further optimization or expansion of the diagnostic armamentarium. We will reflect upon the diagnostic opportunities provided by new technologies including mass spectrometry and next-generation nucleic acid sequencing. Finally, we will review the (im)possibilities of rapidly developing new in vitro diagnostic tools for diseases of which the causative agents are fastidiously growing and therefore hard to detect.

Isolated hepatosplenic abscess from cat scratch disease in a patient with HIV

Bartonella henselae infection, or cat scratch disease, typically is a self-limiting disease presenting as lymphadenopathy and fever after a bite or scratch from a cat. The most commonly reported presentation in immunocompromised patients includes bacillary angiomatosis and peliosis hepatitis, which resemble Kaposi's sarcoma. Isolated hepatosplenic abscess without diffuse lymphadenopathy or vasoproliferative disease is seldom reported in adult immunocompromised patients. Although several advances have been made in identifying the organism and antibodies with serological tests, biopsy, and polymerase chain reaction, there is little information about treatment. We report a case of an isolated hepatosplenic abscess without lymphadenopathy or vasoproliferative disease caused by B. henselae in an adult immunocompromised patient with HIV.

Bartonellosis in transplant recipients: A retrospective single center experience

BACKGROUND

Bartonellosis is a rare but challenging condition to diagnose with a spectrum of clinical presentations in the immunocompromised host.

AIM

To further characterize the presentation of Bartonella henselae (B. henselae) infections in solid organ and hematopoietic stem cell transplant recipients.

METHODS

We conducted a single-center retrospective study of all B. henselae testing for 5012 transplant recipients receiving care at a single institution between 2011 and 2018.

RESULTS

We identified 38 patients who underwent testing for B. henselae, and three of 38 were found to have bartonellosis. Two of the patients were renal transplant recipients who presented with visceral bartonellosis and symptoms concerning for post-transplant lymphoproliferative disorder. One autologous stem cell transplant recipient presented with cat scratch disease. We detail the clinical courses of these three cases and review the literature concerning the clinical presentations, differential diagnosis, and limitations of diagnostic tests for B. henselae infections in transplant recipients.

CONCLUSION

Although the incidence of B. henselae infection in transplant recipients is unknown, it merits inclusion in the differential diagnosis for fever of unknown origin in this population.

What Is in a Cat Scratch? Growth of Bartonella henselae in a Biofilm

Bartonella henselae (B. henselae) is a gram-negative bacterium that causes cat scratch disease, bacteremia, and endocarditis, as well as other clinical presentations. B. henselae has been shown to form a biofilm in vitro that likely plays a role in the establishment and persistence of the bacterium in the host. Biofilms are also known to form in the cat flea vector; hence, the ability of this bacterium to form a biofilm has broad biological significance. The release of B. henselae from a biofilm niche appears to be important in disease persistence and relapse in the vertebrate host but also in transmission by the cat flea vector. It has been shown that the BadA adhesin of B. henselae is critical for adherence and biofilm formation. Thus, the upregulation of badA is important in initiating biofilm formation, and down-regulation is important in the release of the bacterium from the biofilm. We summarize the current knowledge of biofilm formation in Bartonella species and the role of BadA in biofilm formation. We discuss the evidence that defines possible mechanisms for the regulation of the genes required for biofilm formation. We further describe the regulation of those genes in the conditions that mimic both the arthropod vector and the mammalian host for B. henselae. The treatment for persistent B. henselae infection remains a challenge; hence, a better understanding of the mechanisms by which this bacterium persists in its host is critical to inform future efforts to develop drugs to treat such infections.

Prevalence and Predictors of Bacterial Contamination in Excisional Lymph Node Biopsies: Implications for Diagnosis and Management

Routine tissue handling exposes lymph node specimens to microbial contamination that can confound microbiological culture results and interfere with diagnosis. The scope and impact of this problem remain poorly understood. We combined over 13 years of lymph node pathology, culture data, and patient records to define the prevalence, predisposing factors, microbiology, and clinical management of false-positive lymph node cultures at a large academic medical center. Nearly one third (31.9%) of 216 cultured lymph nodes yielded bacterial growth. Approximately 90% of positive bacterial cultures grew 1 of 2 common skin-resident taxa-coagulase-negative Staphylococcus and Cutibacterium acnes-with well-documented predispositions for contamination in other clinical settings. Lymph nodes excised from axillary, cervical, and inguinal regions yielded higher positive culture rates than nodes excised from the mediastinum, suggesting proximity to the skin surface may increase contamination risk. Accordingly, cultures from thoracoscopic pulmonary resections displayed contamination rates over 5-fold lower than those from percutaneously accessed lymph nodes. Lymph nodal tissue allocated for culture in the operating room yielded unexpectedly high contamination rates, significantly higher than cultures sent from the frozen section processing area. A significant minority of contamination events were noted in the clinical record and prompted antibiotic therapy on multiple occasions. Collectively, our results illuminate the risk factors contributing to bacterial contamination and argue that routine lymph node bacterial cultures provide minimal clinical benefit for adult patients. This widespread bacterial contamination also warrants cautious implementation of increasingly sensitive molecular microbiology tools for excised tissues.

Bartonella henselae Antibodies in Serum and Oral Fluid Specimens from Cats

Cats are the primary reservoir host for Bartonella henselae(B. henselae), an etiological agent of human bartonellosis, including cat scratch disease. Although Bartonella DNA has been amplified from salivary swabs from cats, dogs and humans, we are not aware of studies investigating Bartonella antibodies in oral fluid (OF). Using inhouse and commercial immunofluorescence antibody assays (IFA), the objective of this study was to detect and compare antibodies against B. henselae in paired OF and serum specimens from cats. Specimens were collected from shelter and client-owned cats. For serum specimens, B. henselae seroreactivity was 78% for both the inhouse and commercial IFA assays and 56.8% for OF specimens. Comparing serum and OF specimens, there was moderate Kappa agreement (Cohen's k = 0.434) for detection of B. henselae antibodies. Oral fluid antibodies were more likely measurable in cats with high B. henselae serum antibody titers when compared with low antibody titers. In conclusion, B. henselae OF IFA antibody measurements were less sensitive compared to serum IFA measurements of ≥1:64. Oral fluid antibodies were detected more often in cats with high B. henselae serum antibody titers. Therefore, OF antibodies, detectable by IFA, is of limited utility for epidemiological or diagnostic testing in cats.

Nodular Vascular Transformation of the Lymph Node Sinuses Mimicking Sarcomatoid Change in Renal Cell Carcinoma: A Potential Diagnostic Pitfall

Vascular transformation of the lymph node sinuses (VTS) is an uncommon phenomenon that is believed to occur secondary to obstruction of efferent lymphatics, frequently occuring in retroperitoneal lymph nodes draining cancer. The nodular subtype of VTS, in particular, can mimic metastatic cancer, such as metastatic renal cell carcinoma with sarcomatoid differentiation, potentially resulting in inaccurate tumor grading and/or staging. We present a case of nodular VTS mimicking metastatic renal cell carcinoma with sarcomatoid differentiation in a patient with high-grade clear cell renal cell carcinoma, and explore the relevant differential diagnosis. Awareness of VTS is essential to avoid misdiagnosis of this benign and curative condition.

Case Report: Bartonella quintana Endocarditis Outside of the Europe-African Gradient: Comprehensive Review of Cases within North America

Clinical syndromes associated with Bartonella quintana infection can be insidious and difficult to diagnose for multiple reasons. Clinically, B. quintana can manifest as asymptomatic bacteremia or with subtle subacute constitutional symptoms. Second, it is a fastidious organism that is difficult to identify using traditional culture methods. Last, the body lice vector of B. quintana transmission is likely not uncommon in most patients affected, who are homeless and of low socioeconomic status. Therefore, barriers in seeking medical care and financial constraints for medications are important considerations. The mainstay of literature surrounding B. quintana endocarditis is from Europe and the developing nations. Herein, we describe a case of native valve endocarditis secondary to B. quintana in a homeless male with preexisting valvular disease and undertake a comprehensive literature review of documented B. quintana endocarditis in North America.

Combined Application of Immunohistochemistry and Warthin-Starry Silver Stain on the Pathologic Diagnosis of Cat Scratch Disease

PURPOSE

Cat scratch disease (CSD) is an infectious disorder caused primarily by the bacterium Bartonella henselae (B. henselae). Immunohistochemistry (IHC) and Warthin-Starry silver stain (WS) are considered to be indispensable to diagnose CSD in combination with morphologic characteristics. In this study, we retrieved and reviewed 46 cases of paraffin-embedded lymphadenitis with histologic and/or clinical suspicion of CSD between 2014 and 2018, and detected B. henselae by IHC and WS, respectively, and evaluated the application significance of IHC and WS for the detection of B. henselae and validated their values in the pathologic diagnosis of CSD.

MATERIALS AND METHODS

B. henselae was detected by IHC and WS; validation of 2 methods for detecting B. henselae was evaluated by sensitivity, specificity, false-positive rate, false-negative rate, precision, negative predictive value, and agreement rate.

RESULTS

Microscopically, suppurative granulomas and/or multiple stellate microabscesses were observed in the accessory cortex of lymph nodes, especially near the subcapsule. Our results showed that 80.4% (37/46) of cases were positive for B. henselae by IHC, manifesting mainly punctuate, granular, or linear to outline the shape of bacteria. However, the positive rate of B. henselae by the WS method was 52.2% (24/46). There was a significant difference between IHC and WS (P=0.023). Moreover, a positive percentage of B. henselae was 97.8% (45/46), which was detected by the combined application of IHC and WS. The combination of IHC and WS exhibited high sensitivity (97.8%) and good agreement rate (86.5%).

CONCLUSION

The combined application of the IHC and WS method may have important clinical advantages, which is with the highest sensitivity and agreement rate for pathologic diagnosis of CSD.

Bartonella infections in cats and dogs including zoonotic aspects

Bartonellosis is a vector-borne zoonotic disease with worldwide distribution that can infect humans and a large number of mammals including small companion animals (cats and dogs). In recent years, an increasing number of studies from around the world have reported Bartonella infections, although publications have predominantly focused on the North American perspective. Currently, clinico-pathological data from Europe are more limited, suggesting that bartonellosis may be an infrequent or underdiagnosed infectious disease in cats and dogs. Research is needed to confirm or exclude Bartonella infection as a cause of a spectrum of feline and canine diseases. Bartonella spp. can cause acute or chronic infections in cats, dogs and humans. On a comparative medical basis, different clinical manifestations, such as periods of intermittent fever, granulomatous inflammation involving the heart, liver, lymph nodes and other tissues, endocarditis, bacillary angiomatosis, peliosis hepatis, uveitis and vasoproliferative tumors have been reported in cats, dogs and humans. The purpose of this review is to provide an update and European perspective on Bartonella infections in cats and dogs, including clinical, diagnostic, epidemiological, pathological, treatment and zoonotic aspects.

Bartonella spp. as a Possible Cause or Cofactor of Feline Endomyocarditis-Left Ventricular Endocardial Fibrosis Complex

Endomyocarditis is a commonly detected post-mortem finding in domestic cats presenting for sudden onset cardiovascular death, yet the aetiology remains unresolved. Cats are documented reservoir hosts for Bartonella henselae, the infectious cause of cat scratch disease in man. Various Bartonella spp. have been associated with culture-negative endocarditis, myocarditis and sudden death in man and animals. We hypothesized that Bartonella spp. DNA could be amplified more often from the hearts of cats with feline endomyocarditis-left ventricular endocardial fibrosis (FEMC-LVEF) complex compared with cats with hypertrophic cardiomyopathy (HCM) or cats with grossly and microscopically unremarkable hearts (designated non-cardiac disease controls). Formalin-fixed and paraffin wax-embedded, cardiac tissues from 60 domestic and purebred cats aged 3 months to 18 years were examined, and histological features were recorded. Cardiac tissue sections were tested for Bartonella DNA using multiple 16-23S intergenic transcribed spacer region polymerase chain reaction (PCR) primer sets, including two Bartonella genera, a Bartonella koehlerae species-specific and a Bartonella vinsonii subsp. berkhoffii-specific assay, followed by DNA sequence confirmation of the species or genotype. Special precautions were taken to avoid DNA cross-contamination between tissues. Bartonella spp. DNA was amplified by PCR and sequenced from 18 of 36 cats (50%) with FEMC-LVEF and 1/12 (8.3%) cats with HCM. Bartonella spp. DNA was not amplified from any non-cardiac disease control hearts. Based on PCR/DNA sequencing, one Bartonella spp. was amplified from 10 cats, while the remaining eight were coinfected with more than one Bartonella spp. To our knowledge, this study represents the first documentation of B. vinsonii subsp. berkhoffii genotype I infection in cats (n = 11). Fluorescence in-situ hybridization testing facilitated visualization of Bartonella bacteria within the myocardium of four of seven PCR-positive FEMC-LVEF hearts. Collectively, these findings support the hypothesis that Bartonella spp. may play a primary role or act as a cofactor in the pathogenesis of FEMC-LVEF. Studies involving cats from other geographical regions and definitive demonstration of Bartonella spp. within regions of inflammation are needed to confirm an association between Bartonella spp. and FEMC-LVEF induced morbidity and mortality in cats.

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.

Role of fine needle aspiration biopsy cytology in the diagnosis of infections

The role of fine needle aspiration biopsy (FNAB) cytology in diagnosing infections has expanded due to the increase in the number of immune compromised patients and the increasing role of FNAB in the developing world where infection is a major cause of illness. FNAB has become the first procedural test in cases where the clinical and imaging findings suggest an infectious lesion or where there is a differential diagnosis of infection or metastatic or primary tumor. This applies to FNAB of palpable or image directed or deep seated lesions accessed by EUS and EBUS. This article details a recommended approach and technique for FNAB of infectious lesions, and discusses the role of rapid on site evaluation and the application of ancillary testing including the rapidly expanding array of molecular tests based on FNAB material. The utility of recognizing suppurative and granulomatous infectious patterns in FNAB direct smears, and the specific cytomorphological features on routine Papanicolaou and Giemsa stains and on special stains of FNAB smears is described for a large number of bacterial, fungal, viral, parasitic, and protozoan infections. The role of cytopathologists is to now train cytopathologists in sufficient numbers to provide FNAB services, teach trainee cytopathologists and cytotechnologists, and to encourage our clinical colleagues to use FNAB in the diagnosis of infections and other lesions to the benefit of patients and the medical system. Diagn. Cytopathol. 2016;44:1024-1038. © 2016 Wiley Periodicals, Inc.

Disseminated cat-scratch disease: case report and review of the literature

Cat scratch disease (CSD) can present as a systemic disease in 5-10% of cases and lead to various disease entities. A previously healthy 16-month-old boy presented with fever for 7 days without other obvious symptoms. Abdominal computed tomography scan demonstrated enlarged right inguinal lymph nodes and multiple small round hypodensities in the spleen. Despite antibiotic treatment for 1 week, the fever persisted and the intrasplenic lesions progressed. Inguinal lymph node biopsy confirmed CSD by immunohistochemistry staining. The diagnosis of CSD was also supported by a history of contact, imaging and serological findings. The patient recovered after treatment with azithromycin for a total of 5 weeks and, in serial follow-up, the hepatosplenic micro-abscesses resolved after 4th months.

Clinicocytopathologic correlation in an atypical presentation of lymphadenopathy with review of literature

OBJECTIVES

To present a clinicocytopathologic correlation of an atypical case of cat scratch disease (CSD) involving retroperitoneal lymph nodes, with emphasis on communication between service teams for managing lymphadenopathy of unknown origin. We consider clinical and cytologic differential diagnoses and review the literature on atypical cases of CSD, with emphasis on abdominal presentation and cytologic findings.

METHODS

Clinical services met with the cytology service to review clinical and pathologic features. Literature was reviewed via PubMed search (Harbor-UCLA subscriptions). Immunohistochemistry and Steiner silver stains were performed by Harbor-UCLA Department of Pathology. Enzyme-linked immunosorbent assay IgG and IgM Bartonella henselae titers were carried out by Quest Nichols Institute.

RESULTS

Fine-needle aspirate Diff-Quik and Papanicolaou smears and H&E-stained cell block showed abundant histiocytes, monocytoid B cells, and numerous neutrophils associated with necrosis corresponding to a late stage of CSD infection. Silver stain was positive for clumps of pleomorphic organisms. IgM and IgG antibody titers were elevated.

CONCLUSIONS

The cytologic findings of CSD in an atypical abdominal presentation are similar to those of a classic presentation. Laboratory workup for atypical CSD should include at least two other modalities aside from cytomorphologic features. Close clinical and cytologic correlation avoided potentially unnecessary and harmful surgery and enabled timely treatment.

Multiplex SYBR® green-real time PCR (qPCR) assay for the detection and differentiation of Bartonella henselae and Bartonella clarridgeiae in cats

A novel SYBR^® green-real time polymerase chain reaction (qPCR) was developed to detect two Bartonella species, B. henselae and B. clarridgeiae, directly from blood samples. The test was used in blood samples obtained from cats living in animal shelters in Southern Brazil. Results were compared with those obtained by conventional PCR targeting Bartonella spp. Among the 47 samples analyzed, eight were positive using the conventional PCR and 12 were positive using qPCR. Importantly, the new qPCR detected the presence of both B. henselae and B. clarridgeiae in two samples. The results show that the qPCR described here may be a reliable tool for the screening and differentiation of two important Bartonella species.

Limited yield of diagnoses of intrahepatic infectious causes of canine granulomatous hepatitis from archival liver tissue

Canine granulomatous hepatitis is an uncommon morphologic diagnosis that has been associated with a variety of diseases, including a number of systemic infectious etiologies. Formalin-fixed, paraffin-embedded (FFPE) tissues are typically the only source of liver tissue remaining for additional testing for the presence of infectious disease within granulomas. It is unclear if the more common infectious culprits of granulomatous hepatitis can be identified from such specimens. The aim of the current study was to retrospectively investigate archival FFPE liver tissue from dogs with granulomatous hepatitis for the presence of infectious agents. Semiquantitative analysis of copper accumulation in liver specimens was also performed. Medical records were examined for recorded evidence of systemic infectious disease diagnosis. Formalin-fixed, paraffin-embedded liver was prospectively evaluated for infectious agents via differential staining techniques (n = 13), eubacterial fluorescent in situ hybridization (n = 11), and Bartonella polymerase chain reaction assays (n = 15). An infectious cause of granulomatous hepatitis was not identified within liver tissue from any dog using these diagnostic methodologies. Six out of 25 (24%) dogs were diagnosed with concurrent systemic or localized bacterial infections at the time of presentation. Nine out of 17 (53%) dogs had excessive hepatic copper accumulation when evaluated by a semiquantitative histologic grading scheme or quantitative copper analysis. As definitive infectious causes of granulomatous hepatitis were not identified within archival liver biopsy samples, it was concluded that investigation of infectious etiologies within FFPE liver specimens using these diagnostic approaches may be of low yield.

Granulomatous hepatitis due to Bartonella henselae infection in an immunocompetent patient

Background

Bartonella henselae (B. henselae) is considered a rare cause of granulomatous hepatitis. Due to the fastidious growth characteristics of the bacteria, the limited sensitivity of histopathological stains, and the non-specific histological findings on liver biopsy, the diagnosis of hepatic bartonellosis can be difficult to establish. Furthermore, the optimal treatment of established hepatic bartonellosis remains controversial.

Case presentation

We present a case of hepatic bartonellosis in an immunocompetent woman who presented with right upper quadrant pain and a five cm right hepatic lobe mass on CT scan. The patient underwent a right hepatic lobectomy. Surgical pathology revealed florid necrotizing granulomatous hepatitis, favoring an infectious etiology. Despite extensive histological and serological evaluation a definitive diagnosis was not established initially. Thirteen months after initial presentation, hepatic bartonellosis was diagnosed by PCR studies from surgically excised liver tissue. Interestingly, the hepatic granulomas persisted and Bartonella henselae was isolated from the patient's enriched blood culture after several courses of antibiotic therapy.

Conclusion

The diagnosis of hepatic bartonellosis is exceedingly difficult to establish and requires a high degree of clinical suspicion. Recently developed, PCR-based approaches may be required in select patients to make the diagnosis. The optimal antimicrobial therapy for hepatic bartonellosis has not been established, and close follow-up is needed to ensure successful eradication of the infection.

Identification of Bartonella henselae in 2 cats with pyogranulomatous myocarditis and diaphragmatic myositis

Most cats infected with Bartonella henselae remain outwardly healthy carriers for years; however, self-limiting fever, transient anemia, neurologic dysfunction, lymphadenopathy, reproductive disorders, aortic valvular endocarditis, and neutrophilic myocarditis have been described in experimentally or naturally infected cats. Two cats in a North Carolina shelter died with pyogranulomatous myocarditis and diaphragmatic myositis. Bacteria were visualized in the lesions by Warthin-Starry silver impregnation and by B. henselae immunohistochemistry. B. henselae DNA was amplified and sequenced from the heart of 1 cat and from multiple tissue samples, including heart and diaphragm, from the second cat. This study supports a potential association between B. henselae and what has been historically described as "transmissible myocarditis and diaphragmitis" of undetermined cause in cats.

Combining cytomorphology and serology for the diagnosis of cat scratch disease

Cat scratch disease (CSD) is a self limited zoonotic disease that presents most commonly as a regional lymphadenopathy. We are reporting a case of a 25-year-old male patient who presented with fever and large right inguinal lymphadenopathy. The diagnosis of cat scratch disease was confirmed based on the characteristic cytopathological features on aspirate smears from the lymph node and the serological titers for Bartonella henselae. This case report emphasizes the importance of combining Bartonella serology, and cytopathology in the diagnostic work-up of febrile lymphadenopathy and suspected CSD since the culture of this organism is arduous.