Murine Typhus and Febrile Illness, Nepal

Murine typhus was diagnosed by PCR in 50 (7%) of 756 adults with febrile illness seeking treatment at Patan Hospital in Kathmandu, Nepal. Of patients with murine typhus, 64% were women, 86% were residents of Kathmandu, and 90% were unwell during the winter. No characteristics clearly distinguished typhus patients from those with blood culture–positive enteric fever

Evidence of Transfer by Conjugation of Type IV Secretion System Genes between Bartonella Species and Rhizobium radiobacter in Amoeba

Background: Bartonella species cospeciate with mammals and live within erythrocytes. Even in these specific niches, it has been recently suggested by bioinformatic analysis of full genome sequences that Lateral Gene Transfer (LGT) may occur but this has never been demonstrated biologically. Here we describe the sequence of the B. rattaustraliani (AUST/NH4 T) circular plasmid (pNH4) that encodes the tra cluster of the Type IV secretion system (T4SS) and we eventually provide evidence that Bartonella species may conjugate and exchange this plasmid inside amoeba. Principal Findings: The T4SS of pNH4 is critical for intracellular viability of bacterial pathogens, exhibits bioinformatic evidence of LGT among bacteria living in phagocytic protists. For instance, 3 out of 4 T4SS encoding genes from pNH4 appear to be closely related to Rhizobiales, suggesting that gene exchange occurs between intracellular bacteria from mammals (bartonellae) and plants (Rhizobiales). We show that B. rattaustraliani and Rhizobium radiobacter both survived within the amoeba Acanthamoeba polyphaga and can conjugate together. Our findings further support the hypothesis that tra genes might also move into and out of bacterial communities by conjugation, which might be the primary means of genomic evolution for intracellular adaptation by cross-talk of interchangeable genes between Bartonella species and plant pathogens. Conclusions: Based on this, we speculate that amoeba favor the transfer of genes as phagocytic protists, which allows fo

"Candidatus Bartonella thailandensis" : a new genotype of Bartonella identified from rodents

Bartonella species, intracellular parasite of erythrocytes and endothelial cells, are zoonotic pathogens of wild and domestic animals including rodents. Many species of rodents are commensally infected with a few Bartonella species in Asia. However, there are only few reports on detection of Bartonella in Thailand. Our objective was to detect the presence of Bartonella species in rodents from Thailand. Among 247 rodents captured in five provinces from Thailand we identified Bartonella species using molecular methods targeting three genes i.e. citrate synthase (gltA), beta-subunit of the RNA polymerase (rpoB) and cell division protein gene (ftsZ) and the 16S-23S rRNA intergenic spacer (ITS). Overall, we found 21 rodents being infected with a Bartonella species including seven B. coopersplainsensis, four B. phoceensis, six B. queenslandensis, one B. rochalimae, one Bartonella sp. RN24BJ and two genotypes of a new Bartonella that we propose to give the provisional status "Candidatus Bartonella thailandensis". To the best of our knowledge, these Bartonella species have been detected for the first time in Thailand

Partial disruption of translational and posttranslational machinery reshapes growth rates of Bartonella birtlesii

Specialization of bacteria in a new niche is associated with genome repertoire changes, and speciation in bacterial specialists is associated with genome reduction. Here, we tested a signature-tagged mutant library of 3,456 Bartonella birtlesii clones to detect mutants that could grow rapidly in vitro. Overall, we found 124 mutants that grew faster than the parental wild-type strain in vitro. We sequenced the genomes of the four mutants with the most rapid growth (formed visible colonies in only 1 to 2 days compared with 5 days for the wild type) and compared them to the parental isolate genome. We found that the number of disrupted genes associated with translation in the 124 rapid-growth clones was significantly higher than the number of genes involved in translation in the full genome (P < 10(-6)). Analysis of transposon integration in the genome of the four most rapidly growing clones revealed that one clone lacked one of the two wild-type RNA ribosomal operons. Finally, one of the four clones did not induce bacteremia in our mouse model, whereas infection with the other three resulted in a significantly lower bacterial count in blood than that with the wild-type strain. IMPORTANCE: Here, we show that specialization in a specific niche could be caused by the disruption of critical genes. Most of these genes were involved in translation, and we show that evolution of obligate parasitism bacteria was specifically associated with disruption of translation system-encoding genes