In this study, sera from 116 children without clinical evidence of cat scratch disease (CSD) and sera from 19 children with CSD were investigated by two different immunofluorescent assays (test A and test B) to evaluate the seroprevalence of Bartonella henselae antibodies in this population. Antibodies against Bartonella henselae were found in noninfected children only in low titers: 13% and 3.5% of serum samples were positive by test A and test B, respectively. IgG titers as determined by test A ranged from 1:64 to 1:256, whereas test B did not yield titers >1:64. Of the 19 children with CSD, 7 (37%) and 5 (26%) had low antibody titers (1:64-1:256) on admission by test A and test B, respectively. In such cases, IgM antibodies against Bartonella henselae and/or a titer increase in the following weeks are required to prove suspected CSD. The results indicate that the seroprevalence of Bartonella henselae antibodies in children without evidence of CSD is low, and that the results may differ depending on the tests being used. Low antibody titers, however, were found not only in healthy children but also among patients with CSD, which could be indicative of the beginning or of the end of an illness. Currently, only few data are available concerning the seroprevalence of antibodies to Bartonella spp. among children. Although children are often affected by CSD, the specificity of most tests has been evaluated by investigating blood donors, who are usually adults. Several different serological tests are used for the diagnosis of CSD, including the immunofluorescence assay, the enzyme-linked immunosorbent assay, and Western blot (WB) analysis. The sensitivities of different IFAs range from 14 to 100%, depending on the antigen used, the cut-off chosen, and the test procedures. The current diagnostic value of different serological tests for diagnosis of CSD is reviewed.

Cat scratch disease (CSD) is a common cause of subacute regional lymphadenopathy, not only in children but also in adults. Serological and molecular studies demonstrated that Bartonella henselaeis the etiologic agent in most cases of CSD. Amplification of B. henselae DNA in affected tissue and detection of antibodies toB. henselae are the two mainstays in the laboratory diagnosis of CSD. We designed a retrospective study and investigated formalin-fixed, paraffin-embedded lymph nodes from 60 patients (25 female, 35 male) with histologically suspected CSD by PCR amplification. The sensitivities of two different PCR assays were compared. The first primer pair amplified a 296-bp fragment of the 16S rRNA gene in 36 of the 60 samples, corresponding to a sensitivity of 60%. The second primer pair amplified a 414-bp fragment of thehtrA gene in 26 of the 60 lymph nodes, corresponding to a sensitivity of 43.3%. Bartonella DNA could be detected in a total of 39 (65%) of the 60 lymph nodes investigated. However, histopathologic findings are typical but not specific for CSD and cannot be considered as a “gold standard” for diagnosis of CSD. The sensitivity of the PCR assays increased from 65 to 87% if two criteria (histology and serology) were used in combination for diagnosis of CSD. Two genotypes (I and II) of B. henselae are described as being involved in CSD. Genotype I was found in 23 (59%) and genotype II was found in 9 (23%) of the 39 PCR-positive lymph nodes. Seven (18%) lymph nodes were negative in both type-specific PCR assays. Thirty (50%) of our 60 patients were younger than 20 years old (15 were younger than 10 years), 20 (33%) were between 21 and 40 years old, and 10 (17%) patients were between 41 and 84 years old. Our data suggest that detection of Bartonella DNA in patients’ samples might confirm the histologically suspected diagnosis of CSD.

One hundred ninety-three Streptococcus agalactiae isolates of neonatal origin and 146 isolates from adult women were analyzed for macrolide resistance and investigated for clonality. Among erythromycin-resistant isolates, serotype V turned out to be the most frequent. Comparative pulsed-field gel electrophoresis analysis revealed genetic clustering of resistant strains and predominance of a single clone family within an otherwise heterogeneous serotype V population. [GBS]) is the leading cause of meningitis and early-onset sepsis in neonates (3,21). Penicillin or ampicillin is the drug of choice for prophylaxis and treatment of GBS disease (1, 5). However, erythromycin and clindamycin are the recommended second-line drugs and the first alternative in case of a ␤-lactam allergy. In recent years, increasing macrolide resistance rates have been reported (9,15,16,17,19). Resistance mechanisms include target site modification mediated by erm genes leading to resistance to macrolides-lincosamides-streptogramin B (MLS phenotype) with either inducible or constitutive expression or an efflux mechanism encoded by mef genes mediating resistance only to 14-and 15-membered macrolides (M phenotype). After the first description of serotype V in 1977 (26), several studies reported a major increase of serotype V GBS among clinical isolates in the early 1990s (8,13). To analyze the recent increase in macrolide resistance among GBS isolates in our region, the present study aimed to explore the issue of a clonal spread of resistant strains by means of randomly amplified polymorphic DNA (RAPD) analysis and restriction digest patterns (RDP) derived from pulsed-field gel electrophoresis (PFGE). Moreover, a possible correlation between the increase of a certain serotype and macrolide resistance was explored. Streptococcus agalactiae (group B StreptococcusThe bacterial strains used in this study have been presented previously (20). In brief, of 193 neonatal GBS strains, 26 invasive isolates were cultured from blood or cerebrospinal fluid while 167 isolates were grown from urine samples and swab cultures. A total of 146 GBS isolates from vaginal swabs of pregnant women were randomly collected. Serotyping was performed by using an enzymatic extraction method (2). All erythromycin-resistant isolates were screened by PCR analysis for erythromycin resistance genes (mefA or mefE, ermB, and ermTR) by using primers previously described (7,23,24). PCR assays were reproducibly repeated at least three times for every strain. Differentiation of specific MLS phenotypes was performed by use of a triple-disk test (10). For RAPD analysis, the core sequence of phage M13 and the previously described primer OPS16 were used (6, 12) and visual inspection of bands served to compare RAPD patterns for similarity. Different isolates with the same migration distances of all visible bands were considered highly similar. The presence or absence of two distinct bands was deemed to indicate a difference. Chromosomal DNA of GBS strains was prepared by modifications o...

Seventeen isolates of Bartonella henselae from the region of Freiburg, Germany, obtained from blood cultures of domestic cats, were examined for their genetic heterogeneity. On the basis of different DNA fingerprinting methods, including pulsed-field gel electrophoresis (PFGE), enterobacterial repetitive intergenic consensus (ERIC)-PCR, repetitive extragenic palindromic (REP) PCR, and arbitrarily primed (AP)-PCR, three different variants were identified among the isolates (variants I to III). Variant I included 6 strains, variant II included 10 strains, and variant III included only one strain. By all methods used, the isolates could be clearly distinguished from the type strain, Houston-1, which was designated variant IV. A previously published type-specific amplification of 16S rDNA differentiated two types of the B. henselaeisolates (16S rRNA types 1 and 2). The majority of the isolates (16 of 17), including all variants I and II, were 16S rRNA type 2. Only one isolate (variant III) and the Houston-1 strain (variant IV) comprised the 16S rRNA type 1. Comparison of the 16S rDNA sequences from one representative strain from each of the three variants (I to III) confirmed the results obtained by 16S rRNA type-specific PCR. The sequences from variant I and variant II were identical, whereas the sequence of variant III differed in three positions. All methods applied in this study allowed subtyping of the isolates. PFGE and ERIC-PCR provided the highest discriminatory potential for subtypingB. henselae strains, whereas AP-PCR with the M13 primer showed a very clear differentiation between the four variants. Our results suggest that the genetic heterogeneity of B. henselae strains is high. The methods applied were found useful for typing B. henselae isolates, providing tools for epidemiological and clinical follow-up studies.