Ophthalmic manifestations of bartonella infection

Central retinal vein occlusion associated with Bartonella henselae infection

PURPOSE

To report the clinical features and treatment course of a case of central retinal vein occlusion (CRVO) as the initial sign of ocular Bartonella henselae (B. henselae) infection.

OBSERVATION

A 36-year-old male was evaluated for unilateral vision loss. He denied prodromal symptoms but reported prior exposure to fleas. Best corrected visual acuity (BCVA) was 20/400 in the left eye. Clinical examination revealed a CRVO with atypical features including significant peripapillary exudates and peripheral vascular sheathing. Laboratory testing revealed elevated B. henselae IgG titers (1:512) with no abnormalities on hypercoagulability testing. The patient was treated with doxycycline and aflibercept with an excellent clinical response and improvement in BCVA to 20/25 in the left eye two months later.

CONCLUSION

CRVO is a rare but sight-threatening complication of ocular bartonellosis and can be the presenting sign of infection, even in the absence of cat exposure or prodromal symptoms.

The Clinical Profile of Cat-Scratch Disease’s Neuro-Ophthalmological Effects

Cat-scratch disease is an illness caused by Bartonella henselae that occurs as a result of contact with an infected kitten or dog, such as a bite or scratch. It is more prevalent in children and young adults, as well as immunocompromised individuals. There are limited publications examining the features of CSD in patients. As such, the purpose of this research was to assess the clinical neuro-ophthalmological consequences of CSD reported in the literature. Among the ophthalmologic disorders caused by cat-scratch disease in humans, Parinaud oculoglandular syndrome, uveitis, vitritis, retinitis, retinochoroiditis and optic neuritis are the most prevalent. The neurological disorders caused by cat-scratch disease in humans include encephalopathy, transverse myelitis, radiculitis, and cerebellar ataxia. The current review addresses the neuro-ophthalmological clinical manifestations of cat-scratch disease, as described in papers published over the last four decades (1980–2022). All the data gathered were obtained from PubMed, Medline and Google Scholar. The current descriptive review summarizes the most-often-encountered clinical symptomatology in instances of cat-scratch disease with neurological and ocular invasion. Thus, the purpose of this review is to increase knowledge of cat-scratch disease’s neuro-ophthalmological manifestations.

Posterior Segment Manifestations of Cat-scratch Disease: A Mini-review of the Clinical and Multi-modal Imaging Features

Bartonella henselae, an intracellular gram-negative bacillus, is usually transmitted from infected cats to humans by direct or indirect contact. The bacterium mainly infects erythrocytes and endothelial cells thereby leading to so called cat-scratch disease (CSD) and may present with various localised and/or systemic manifestations. The eye is the most commonly affected organ in disseminated CSD and ocular bartonellosis has been reported in 5-10% of CSD patients. The most well-known clinical feature of ocular bartonellosis is neuroretinitis but various sight-threatening posterior segment lesions involving the optic nerve, retinal vasculature, retinal and choroidal tissues may occur during the disease course. This mini-review aims to overview both the clinical and multi-modal imaging characteristics of posterior ocular segment manifestations of CSD.

Atypical Manifestations of Cat-Scratch Disease, United States, 2005-2014

Atypical manifestations that can be severe and difficult to diagnosis develop in 5%-20% of patients with cat-scratch disease. To clarify the epidemiology of atypical cat-scratch disease in the United States, we analyzed data from the 2005-2014 MarketScan national health insurance claims databases by using the International Classification of Diseases, 9th Revision, Clinical Modification, codes for cat-scratch disease and selected atypical manifestations: retinitis/neuroretinitis, conjunctivitis, neuritis, encephalitis, hepatosplenic disease, osteomyelitis, erythema nodosum, and endocarditis. Atypical cat-scratch disease accounted for 1.5% of all cases, resulting in an average annual incidence of 0.7 cases/100,000 population. Atypical cat-scratch disease was associated with increased risk for hospitalization (risk ratios 8.77, 95% CI 6.56-11.72) and occurred most often in female patients 10-14 years of age. Ocular (48.7%), hepatosplenic (24.6%), and neurologic (13.8%) manifestations were most common among patients. A more comprehensive understanding of atypical cat-scratch disease can improve patient diagnosis and potentially elucidate pathophysiology of the disease.

Bartonella hanselae retinitis patient evaluated with multimodal retinal exams

BACKGROUND

Cat scratch disease is a systemic infectious illness caused by the bacterium Bartonella henselae. The most common ophthalmological involvement due to infection by Bartonella is Parinaud oculoglandular syndrome, whereas the most common posterior segment findings are neuroretinitis and subsequent late macular star. Moreover, other findings, such as retinal or subretinal lesions, intermediate uveitis and angiomatous lesions, may be present.

CASE PRESENTATION

A 37-year-old female patient with retinal findings and serological confirmation of Bartonella infection was evaluated via multimodal retinal exams. The patient received treatment with doxycycline 100 mg twice daily for 2 weeks. One month after treatment, complete improvement of her visual scotoma symptoms was confirmed. A swept-source optical coherence tomography exam also showed decreases in the size and intraretinal extension of the lesion. Improvement of light perception at the affected area was confirmed by microperimetry.

CONCLUSIONS

Bartonella henselae infection, particularly retinitis, can present a variable spectrum of clinical and ophthalmological findings. Multimodal retinal exams can clearly identify lesion characteristics, thus providing important information for diagnosis and the evaluation of lesion improvement after antibiotic treatment.

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.

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.

Update on Bartonella neuroretinitis

PURPOSE

To review the clinical features, diagnosis, treatment modalities, and prognosis of Bartonella-associated neuroretinitis.

METHODS

This is a narrative review on Bartonella-associated neuroretinitis including general and ophthalmological aspects of the disease. A comprehensive literature review between January 1950 and September 2018 was conducted in PubMed database. Epidemiology, clinical features, diagnosis, treatment, and prognosis of Bartonella neuroretinitis were reviewed.

RESULTS

Cat scratch disease (CSD) is a worldwide distributed systemic infectious disease caused by a bacterium, Bartonella henselae (B. henselae) which is usually transmitted to humans through contact with infected cats. Ocular manifestations of CSD are diverse, with neuroretinitis and superficial retinal infiltrates being the most common and typical manifestations. Neuroretinitis typically presents as optic disc edema with a partial or complete macular star in association with mild vitritis. Macular star may be absent at the initial presentation, becoming evident 1-2 weeks after the onset of optic disc edema. Diagnosis of CSD is confirmed by reliable laboratory tests. Neuroretinitis usually has a self-limited course. Antibiotic therapy is required for severe systemic disease and vision-threatening ocular involvement. The adjunctive use of oral corticosteroids may further improve the visual outcome.

CONCLUSIONS

The diagnosis of Bartonella-associated neuroretinitis is based on typical clinical findings and positive serology. The prognosis is usually favorable in immunocompetent individuals.

Bartonella henselae- and quintana-associated uveitis: a case series and approach of a potentially severe disease with a broad spectrum of ocular manifestations

PURPOSE

To evaluate the clinical manifestations of intraocular inflammation associated with Bartonella infection and describe the assessment and management of patients with cat-scratch disease (CSD).

METHODS

This is a retrospective review of the clinical records of patients diagnosed with Bartonella henselae and Bartonella quintana intraocular inflammation from 2011 to 2018 in the Department of Ocular Inflammations and Infections of the University Eye Clinic of Ioannina (Greece). An analysis of the current literature concerning Bartonella-related intraocular infections was also carried out.

RESULTS

This is a retrospective study of 13 patients (7 males and 6 females) with a mean age of 39.2 years that were diagnosed with unilateral intraocular inflammation, except one case with bilateral affection, attributed to Bartonella (either henselae or quintana). Twelve (12) patients (92.3%) had a positive history of traumatic cat contact. The main ocular clinical findings with regard to the type of uveitis included neuroretinitis in 5 eyes (38.5%), vasculitis in 3 eyes (23.1%), iridocyclitis in 2 eyes (15.4%), intermediate uveitis in 2 eyes (15.4%), posterior uveitis in 1 eye (7.7%), panuveitis in 2 eyes (15.4%), retinochoroiditis in 2 eyes (15.4%), vitritis in 1 eye (7.7%), peripheral choroidal granuloma in 1 eye (7.7%). Immunoglobulin (Ig) G was positive in all cases. All patients were treated with antibiotics (mainly rifampicin, doxycycline and azithromycin). The visual acuity was noted to be improved in all patients after treatment, but some of them experienced disturbing complications.

CONCLUSION

CSD may manifest with various ocular pathological findings. Taking into consideration the increasing frequency of infections by B. henselae and B. quintana, clinicians should always incorporate CSD in the differential diagnosis of such presentations of uveitis. Educating vulnerable groups (children, immunosuppressed, etc.) and also general population, the appropriate preventing measures can contribute in limiting the risk of infection.

Ocular manifestations of bartonellosis

PURPOSE OF REVIEW

To review the systemic and ocular complications of Bartonella spp. infections specifically cat scratch disease, encompassing epidemiology, laboratory diagnostics, ophthalmic imagining, and treatment.

RECENT FINDINGS

Recent studies have shown that ocular manifestations occur in approximately 4.4% of cat scratch disease patients. The annual prevalence is lower than previously reported to be approximately 12 500 cases annually. Mainstay treatment continues to be oral antibiotics with and without corticosteroids and is dependent on associated systemic manifestations, age, and patient immune status. More recently anti-VEGF agents have been used for complications such as cystoid macular edema and choroidal neovascularization.

SUMMARY

Bartonella spp. infections continue to be a common cause uveitis with ophthalmic manifestations ranging from neuroretinits, vascular occlusions, to choroidal granulomas. Review of associated risk factors including contact with feline reservoirs will aid in recognition and diagnosis of this disease entity. Laboratory diagnostics continue to improve to help with the diagnosis of this entity.

Analysis of PCR Kinetics inside a Microfluidic DNA Amplification System

In order to analyze the DNA amplification numerically with integration of the DNA kinetics, three-dimensional simulations, including flow and thermal fields, and one-dimensional polymerase chain reaction (PCR) kinetics are presented. The simulated results are compared with experimental data that have been applied to the operation of a continuous-flow PCR device. Microchannels fabricated by Micro Electro-Mechanical Systems (MEMS) technologies are shown. Comprehensive simulations of the flow and thermal fields and experiments measuring temperatures during thermal cycling are presented first. The resultant velocity and temperature profiles from the simulations are introduced to the mathematical models of PCR kinetics. Then kinetic equations are utilized to determine the evolution of the species concentrations inside the DNA mixture along the microchannel. The exponential growth of the double-stranded DNA concentration is investigated numerically with the various operational parameters during PCR. Next a 190-bp segment of Bartonella DNA is amplified to evaluate the PCR performance. The trends of the experimental results and numerical data regarding the DNA amplification are similar. The unique architecture built in this study can be applied to a low-cost portable PCR system in the future.