Bartonella henselae: evidencia serológica en pacientes pediátricos con sospecha clínica de enfermedad por arañazo de gato / Bartonella henselae: Serological evidence in pediatric patients with clinical suspicion of cat scratch disease

La enfermedad por arañazo de gato (EAG) es producida por Bartonella henselae.Afecta principalmente a ninos y el reservorio es el gato doméstico. El diagnóstico de laboratorio se basa en la detección de anticuerpos por inmunofluorescencia indirecta (IFI). El objetivo de este trabajo fue analizar la evidencia serológica de infección por B. henselae en pacientes pediátricos que reunían criterios clínicos/epidemiológicos para la sospecha de EAG. Se estudió a 92 pacientes; de acuerdo con los resultados serológicos, estos fueron categorizados en 4 grupos: 1) IgG (+)/IgM (+), 31,5% (n = 29);2) IgG (-)/IgM (+), 10,9% (n = 10);3) IgG (+)/IgM (-), 9,8% (n = 9), y 4) IgG (-)/IgM (-), 47,8% (n = 44). La divulgación de estos resultados intenta promover futuros trabajos que investiguen la seroprevalencia de Bartonella spp. en Argentina. Esto permitirá conocer la importancia de esta zoonosis en nuestra población y evaluar nuevos puntos de corte para esta técnica serológica.

Cat scratch disease (CSD) is caused by Bartonella henselae, which mainly affects children. The cat is the reservoir. The laboratory diagnosis is based on the detection of antibodies by the Indirect Immunofluorescence (IFI) assay. The objective of this study was to analyze the serological evidence of B. henselae infection in pediatric patients that met the clini-cal/epidemiological criteria for suspected CSD. We studied 92 patients, who were categorized into four serological groups: 1) IgG (+)/IgM(+), 31,5% (n = 29); 2) IgG (-)/IgM(+), 10,9% (n = 10); 3) IgG (+)/IgM(-), 9,8% (n = 9); 4) IgG (-)/IgM(-), 47,8% (n = 44). These findings aim to promote future works for investigating the seroprevalence of Bartonella spp. in Argentina, which will allow us to know the importance of this zoonosis in our population and to evaluate new cut-off points of the technique.

Bartonella henselae en niños con adenitis regional atendidos en un hospital nacional del Perú, 2012 / Bartonella henselae in children with regional adenitis treated in a Peruvian national hospital, 2012

Con el objetivo de determinar la frecuencia de casos seropositivos a Bartonella henselae en niños con adenitis regional atendidos en un hospital nacional del Perú, se realizó un estudio trasversal en 106 niños con adenitis regional mayor de 1 cm de diámetro, de aparición aguda, con tiempo de enfermedad mayor de cinco días, atendidos en el Instituto Nacional de Salud del Niño durante el año 2012. Se definió seropositividad para B. henselae mediante el examen de inmunofluorescencia indirecta, siendo positivos 86 niños (81,1%) con una mediana de edad de 7 años, rango de 5 a 11; en el análisis bivariado se encontraron como factores asociados, edad mayor de 5 años, antecedentes de fiebre, adenopatía mayor de 4 cm y reporte de contacto con gato. En conclusión, los niños con adenitis regional atendidos en este hospital de referencia nacional presentaron una frecuencia alta de serología positiva para B. henselae.

In order to determine the frequency of seropositive cases of Bartonella henselae in children with regional adenitis treated in a national hospital in Peru, a cross-sectional study was conducted in 106 children with regional adenitis greater than 1 cm in diameter. The sample was selected from patients aged 5-11 years seen at the National Institute of Child Health for acute onset of regional adentitis, with more than five days of symptoms. B. henselae seropositivity was defined by indirect immunofluorescence test. We found that 86 children (81.1%) were positive for B.henselae. The median age of the patients was 7 years. In the bivariate analysis, the following associated factors were found: aged 5 years, history of fever, lymphadenopathy greater than 4 cm and reported contact with cat. In conclusion, children with regional adenitis treated in this national referral hospital showed a high frequency of positive serology for B. henselae.

Exactitud y utilidad diagnóstica de la IgM en infecciones por Bartonella henselae / Accuracy and diagnostic utility of IgM in Bartonella henselae infections

Introduction: Laboratory diagnosis of cat scratch disease (CSD) is based on the determination of specific antibodies anti-Bartonella henselae by different techniques. The CDC recommends IgG by immunofluorescent assay (IFA) as the gold standard. Objective: To determine the accuracy and diagnostic utility of anti-B.henselae IgM by IFA for CSD. Material and Methods: Anti-B. henselae IgG was determined in serum of 108 patients with CSD suspicion; in addition, specific IgM was determined separately and blindly by two thoroughly trained laboratory professionals. We calculated sensitivity (S), specificity (Sp), predictive values both positive (PPV) and negative (NPV), and likelihood ratio (LR) for IgM positive (LR +) and negative (LR-). Results: In 37 patients with positive anti-B.henselae IgG, IgM was positive in 16 and negative in 21; in 71 patients with negative IgG, IgM was negative in 69 and positive in 2. Therefore, IgM showed S 43%, E 97%, PPV 88%, NPV 77%, LR (+) 15 and LR (-) 0.58. Conclusions: The results show that a positive IgM supports, but a negative one does not rule out a B. henselae infection. Therefore, IgG should be still considered as the gold standard for the diagnosis of CSD.

Introducción: El diagnóstico de laboratorio de la enfermedad por arañazo de gato (EAG) se basa en la determinación de anticuerpos específicos anti-Bartonella henselae por distintas técnicas. El CDC de E.U.A. recomienda como estándar de oro la IgG mediante inmunofluorescencia (IF). Objetivo: Determinar la exactitud y utilidad diagnóstica de la IgM anti-B. henselae por IF para EAG. Material y Método: En suero de 108 pacientes a quienes se realizó IgG anti-B. henselae por sospecha de EAG, se determinó la presencia de IgM específica, en forma separada y ciega por dos profesionales de laboratorio ampliamente entrenados. Se calculó sensibilidad (S), especificidad (E), valores predictores positivo (VPP) y negativo (VPN) y likelihood ratio (LR) para una IgM positiva (LR+) y negativa (LR-). Resultados: En 37 pacientes con IgG anti-B. henselae positiva, la IgM fue positiva en 16 y negativa en 11; en 71 pacientes con IgG negativa, la IgM fue negativa en 69 y positiva en 2. Por consiguiente, la IgM presentó S 43%, E 97%, VPP 88%, VPN 77%, LR(+) 15 y LR(-) 0,58. Conclusiones: Los resultados sugieren que una IgM positiva apoya el diagnóstico de EAG, pero una negativa no permite descartarlo. Por tanto, la IgG debe seguir considerándose como el estándar de oro para el diagnóstico de infecciones por B. henselae.

Bartonelosis ocular: Reporte de tres casos / Ocular bartonellosis: Report of three clinical cases

The characteristic clinical presentation of cat scratch disease is subacute regional lymphadenopathy; nevertheless, 5-25 percent of Bartonella henselcie infections may present an atypical or systemic form, with potential eye involvement. We describe three clinical cases of ocular bartonellosis in two adolescents and one young adult, who had close contact with cats; all of them presented persistent fever ranging from 15 to 21 days, and two of them developed a sudden unilateral loss of visual acuity associated with optic neuritis. The other patient presented retinal choroiditis and unilateral retinal microgranulomas, with normal visual acuity. Patients received macrolides as sole antimicrobial or in association with rifampin, and one patient was additionally treated with systemic corticoids. The outcome was favorable in two patients; one patient developed a permanent visual deficit. Ocular bartonellosis must be suspected in patients with close contact to cats or with cat scratches whom develop persistent fever and sudden loss of visual acuity.

La enfermedad por arañazo de gato se manifiesta típicamente como una linfadenopatía regional sub-aguda; sin embargo, 5 a 25 por ciento de los pacientes infectados por Bartonella henselae desarrollan formas atípicas o sistémicas de la enfermedad, pudiendo evolucionar con compromiso ocular. Consideramos de interés describir las características clínicas, tratamiento y evolución de tres pacientes con bartonelosis ocular, dos adolescentes y un adulto joven, que tenían antecedentes de contacto y/o rasguño por gatos. Todos cursaron con síndrome febril prolongado, con 15 a 21 días de duración, asociado a pérdida súbita de la agudeza visual unilateral en dos casos, cuya fondoscopia reveló neuritis óptica. El otro paciente presentó retino-coroiditis y microgranulomas retiñíanos, con agudeza visual conservada. Todos recibieron tratamiento antimicrobiano con macrólidos solos o asociados a rifam-picina y uno recibió además corticosteroides sisté-micos. La evolución fue satisfactoria en dos, quedando un paciente con déficit visual permanente. Recomendamos sospechar bartonelosis ocular en pacientes con antecedentes de contacto y/o rasguños por gatos, que cursan con un síndrome febril prolongado y/o disminución súbita de la agudeza visual.

Bartonella native valve endocarditis: the first brazilian case alive and well

Bartonella is an important cause of blood culture-negative endocarditis in recent studies. Seroprevalence studies in the States of Minas Gerais and Rio de Janeiro have shown Bartonella IgG positivity around 14 percent in healthy adults and 40 percent in HIV seropositive adults, respectively. A case report of a 46-year-old white male with moderate aortic regurgitation (AR) due to rheumatic heart disease (RHD), admitted due to worsening heart failure, is presented. Clinical features were apyrexia, anemia, polyclonal hypergammaglobulinemia, hematuria and splenomegaly. He was submitted to surgery due to worsening AR. Histopathology of the excised valve showed active bacterial endocarditis and underlying RHD. Routine blood cultures were negative. Indirect immunofluorescence (IFI) assays for Coxiella burnetii were non-reactive. Bartonella henselae IgG titer was 1:4096 prior to antibiotics and 1:512 14 months after treatment. History of close contact with a young cat during the months preceding his admission was elicited.

Bartonellosis: suggestive case reports in adult and pediatric patients and therapeutic issues

Cat-scratch disease warrants extensive investigation, from an epidemiological, a diagnostic, but especially a therapeutic point of view. Two suggestive episodes of Bartonella henselae-caused cat-scratch disease are reported, and discussed in the light of the most recent literature evidence. The first case occurred in a 60-year-old man, thus suggesting that it is important to maintain an elevated level of suspicion for this disease in adults as well. Both episodes were characterized by a very prolonged and complicated disease course (with the involvement of three lymph node sets in the first case), a need for lymph-node drainage, and apparently negligible activity of many antimicrobial courses, with a very slow local cure. While specific culture and molecular biology techniques proved negative (probably due to late availability of appropriate clinical specimens), indirect immunofluorescence antibody assay was positive since the first weeks of disease, and elevated levels were also fond many months after disease onset. When clinicians face patients with prominent swelling of lymph nodes draining from the upper limbs, cat-scratch disease may be suspected on the grounds of epidemiological and clinical features, with a limited systemic involvement contrasting with a prominent local disease. The significance of specific antibody temporal kinetics in the subacute disease course is still unknown. Although biomolecular assays are now available, the time elapsed from disease onset to clinical diagnosis usually hampers diagnosis, while the roles of surgical debridement and of the unpredictable activity of antimicrobial chemotherapy warrant careful investigation.

Prevalencia de anticuerpos contra Bartonella henselae en niños, en adolescentes y en una población de riesgo ocupacional en Chile / Prevalence of Bartonella henselae antibodies in Chilean children, adolescents and veterinary workers

Background: Bartonella henselae is the causative agent of cat-scratch disease. Aim: To study the seroepidemiology of Bartonella henselae in healthy Chilean children and in a population with occupational risk. Material and methods: Serum IgG antibodies were determined by indirect fluorescence technique in 181 children and adolescents and in 107 technical and professional workers involved in the care of cats. Samples with titers equal to or greater than 64 were considered positive. Results: Twenty four (13.3%) children and 11 (10.3%) occupational risk subjects were seropositive. No significant differences by age and gender were observed. Conclusions: Assuming that seroprevalence indicates level of exposure to Bartonella henselae, these results suggest that this infection is endemic in Chile and, for this reason, the best antibody titer to diagnose acute cat-scratch disease should be higher than the figure recommended by the Centers for Disease Control in the in United States.

Presencia de Bartonella henselae en gatos: cuantificación del reservorio natural y riesgo de exposición humana de esta zoonosis en Chile / Presence of Bartonella henselae in cats, in Chile

Background: The availability of a serologic test for cat scratch disease in humans has allowed the diagnosis of an increasing number of cases of this disease in Chile. Aim: To perform a serological survey for Bartonella henselae among cats in Chile. Material and methods: Blood samples from 187 cats living in three Chilean cities were obtained. IgG antibodies againts Bartonella henselae were measured using indirect immunofluorescence. Blood cultures were done in 60 samples. The presence of Bartonella henselae in positive cultures was confirmed by restriction fragment length polymorphism polimerase chain reaction (RFLP-PCR). Results: The general prevalence of IgG antibodies against Bartonella henselae was 85.6%. No differences in this prevalence were found among cats younger or older than 1 year, or those infested or not infested with fleas. However domestic cats had a lower prevalence when compared with stray cats (73 and 90% respectively, p <0.01). Bartonella henselae was isolated in 41% of blood cultures. All the isolated were confirmed as Bartonella henselae by RFLP-PCR. Conclusions: This study found an important reservoir of Bartonella henselae in Chilean cats and therefore a high risk of exposure in humans who have contact with them.