Bartonella henselae in Italy: a rare seasonal infection

Detection of Bartonella vinsonii subsp. berkhoffii in a HIV patient using metagenomic Next Generation Sequencing

Bartonella species are fastidious, aerobic bacteria that are transmitted by blood-sucking arthropods. Bartonella spp. are responsible for cat scratch disease, Carrion’s disease, bacillary angiomatosis and trench fever. On the other hand, Bartonella vinsonii is rarely reported in the literature and there exist a few reports of systemic infection caused by Bartonella vinsonii in patients with acquired immunodeficiency syndrome. A 31-year-old male (diagnosed with AIDS six years ago) had persistent fever and ulceration in the right knee. The elevated levels of inflammatory markers suggested an infectious aetiology. Despite the negative findings of blood culture, metagenomic Next-Generation Sequencing of plasma detected Bartonella vinsonii. The polymerase chain reaction of whole blood and Sanger sequencing confirmed the mNGS findings. Immunohistochemical staining had later suggested bacillary angiomatosis, which was consistent with Bartonella infection. Following antibiotic treatment, the ulcers subsided significantly, but a high fever persisted. The patient died due to sudden respiratory failure.

Cat-scratch Disease in the Pediatric Population: 6 Years of Evaluation and Follow-up in a Public Hospital in Chile

BACKGROUND

Bartonella henselae is the etiologic agent of cat-scratch disease, which affects the entire world population. Due to how poorly characterized the child population is, the objective was to describe the clinical behavior of this disease in children younger than 16 years of age.

METHODS

This was a descriptive study with prospective follow-up of all children younger than 16 years with clinical and serologic diagnoses between 2013 and 2018.

RESULTS

There were 142 patients; of these, 55.6% had localized disease, 34.5% disseminated with hepatosplenic involvement and 9.8% had atypical disease. The cases of atypical disease were prolonged febrile illness, Parinaud syndrome, subacute bacterial endocarditis/glomerulonephritis and aseptic meningitis. Cervical lymphadenopathy was the most frequent, followed by inguinal adenopathy. There were no differences between the type of manifestation and laboratory values except for a higher erythrocyte sedimentation rate tendency in patients with disseminated and/or atypical disease. The serologic titers throughout were distributed as follows: titer of 1/1024, 71.7%; titer of 1/512, 10.4% and titer of 1/256, 17.9%.

CONCLUSIONS

This is, to our knowledge, the largest series of cat-scratch disease published. We demonstrate that in our environment, the inguinal location is suggestive of this disease, the disseminated presentation, frequent, and that the titers are probably much higher than in other populations, which perhaps indicates the need to re-examine the cut-off point for positivity.

Serological and molecular detection of Bartonella henselae in specimens from patients with suspected cat scratch disease in Italy: A comparative study

Cat scratch disease (CSD) is an infectious disease caused by Bartonella henselae, usually characterized by self-limiting regional lymphadenopathy and fever. Given the low clinical diagnostic sensitivity and specificity of conventional anti-B. henselae indirect immunofluorescence assays (IFAs), real-time polymerase chain reaction (PCR)-based detection of B. henselae is now being proposed as a more sensitive tool to diagnose CSD. Thus, here we have assessed the efficacy of real-time PCR in detecting B. henselae in different specimens from patients with suspected CSD and compared it to that of IFA. From March 2011 to May 2016, at the Microbiology and Virology Unit, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, Turin, Italy, 115 clinical specimens (56 aspirated pus, 39 fresh lymph node biopsies, and 20 whole blood samples) and 99 sera from 115 patients with suspected CSD (62 females and 53 males between the ages of 3 months and 68 years) were analyzed by both real-time PCR, used in a qualitative way, and IFA (IgM and IgG) for the presence of B. henselae. For 16 patients, serological results were not available due to a clinical decision not to request the test. B. henselae DNA positivity was detected by real-time PCR in 37.39% of patients, while 62.61% of them were negative. Thus, patients were divided into two groups: real-time PCR+ (n = 43) and real-time PCR- (n = 72). Real-time PCR screening of whole blood, biopsies, and aspirated pus revealed B. henselae positivity in 40%, 38.46%, and 35.71% of patients, respectively. When we analyzed samples by IFA, we found the presence of B. henselae in 28 out of 99 (28.28%) patients, of which 11 (11.11%) belonged to the real-time PCR+ group and 17 (17.17%) to the real-time PCR- group. Among the 71 seronegative subjects, 16 (16.16%) were found positive for B. henselae by real-time PCR. Thus, by combining the results of both assays, we were able to increase the percentage of B. henselae positive specimens from 27.27% (real-time PCR) or 28.28% (IFA) to 44.44% (real-time PCR+IFA). Altogether, these findings indicate that the early detection of B. henselae in patients with suspicious CSD through combined real-time PCR and serological analyses can lead to a more accurate diagnosis of CSD, thereby allowing prompt and appropriate disease management.