Functional characterization of IScs605, an insertion element carried by tetracycline-resistant Chlamydia suis.

Stable tetracycline resistance in Chlamydia suis is mediated by a family of genomic islands [the tet(C) islands] that are integrated into the chlamydial chromosome. The tet(C) islands contain several plasmid-specific genes, the tet(C) resistance gene and, in most cases, a novel insertion element (IScs605) encoding two predicted transposases. The hypothesis that IScs605 mediated the integration of the tet(C) resistance islands into the C. suis genome was tested using a plasmid-based transposition system in Escherichia coli. Both high- and medium-copy-number plasmids were used as carriers of IScs605 in these experiments. IScs605 integrated into a target plasmid (pOX38) when delivered by either donor plasmid, and integration of the entire donor plasmid was common. IScs605-mediated integration occurred at many positions within pOX38, with 36 of 38 events adjacent to a 5'-TTCAA-3' sequence. Deletions in each of the candidate transposase genes within IScs605 demonstrated that only one of the two ORFs was necessary for the observed transposition activity and target specificity. Analysis of progeny from the mating assays also indicated that IScs605 can excise following integration into a target DNA, and, in each tested case, the sequence 5'-AATTCAA-3' remained at the site of excision. Collectively, these results are consistent with the nucleotide sequence data collected for the tet(C) islands, and strongly suggest that a transposase within IScs605 is responsible for integration of these genomic islands into the C. suis chromosome.

Is there an association between ocular adnexal lymphoma and infection with Chlamydia psittaci? The University of Rochester experience.

Various subsets of extranodal marginal zone lymphomas of mucosa-associated lymphoid tissues (MALT lymphomas) have been associated with infectious organisms. Most notable of these is the association of gastric MALT lymphomas with Helicobacter pylori infection. In a recent publication Ferreri et al. [Ferreri AJ, Guidoboni M, Ponzoni M, De Conciliis C, Dell'Oro S, Fleischhauer K, et al. Evidence for an association between Chlamydia psittaci and ocular adnexal lymphomas. J Natl Cancer Inst 2004;96:586-94] reported the presence of C. psittaci DNA in 80% of 40 ocular adnexal lymphomas. Similar to the gastric MALT lymphoma data, a subset of these patients responded well to antibiotic treatment. We analyzed a set of ocular adnexal lymphomas and benign (non-neoplastic) lesions for evidence of C. psittaci DNA in patients from New York State. No evidence of C. psittaci DNA was seen in seven MALT-type ocular adnexal lymphomas, four non-MALT ocular lymphomas, one Langerhans histiocytosis, and five reactive lymphoproliferations. We eliminated several possible reasons that would cause our study to fail to find C. psittaci DNA, including the presence of PCR inhibitors, inadequate template DNA, and sequence diversity in the target region in C. psittaci. The positive data were based primarily on patients from Italy, while our study involved only patients living in the Northeastern United States. This would suggest possible geographic differences in the etiology of ocular adnexal lymphomas.

Serotyping of US isolates of Chlamydophila psittaci from domestic and wild birds.

The identities of chlamydial strains, which can infect a given host, are important to know for disease prognosis, disease control, and epidemiology. The microimmunofluorescence test (MIFT) was used with a panel of 14 serovar-specific monoclonal antibodies (MAbs) to serotype 150 chlamydial isolates from domestic and wild birds. The isolates were obtained from birds submitted to diagnostic laboratories or during investigation of outbreaks. The 150 US isolates included 96 from the order Psittaciformes, 14 isolates from the order Columbiformes, 2 from the order Passeriformes, 16 from the order Galliformes, 12 from the order Struthioniformes, and 3 from the order Falconiformes. A total of 93, or 97%, of the Psittaciformes isolates were of serovar A; 11, or 79%, of the Columbiformes isolates were of serovar B; 64% of the Galliformes isolates were of serovar D, and all the Struthioniformes isolates were of serovar E. The 3 Falconiformes isolates did not react with any of the MAbs to the avian and mammalian isolates and are presumed to represent a new strain. The results show that specific chlamydial strains are usually associated with certain types of birds and that some serovars may be unusually virulent for certain species of birds. The MIFT using serovar-specific MAbs provides a rapid method to serotype new isolates, making it a useful system for epidemiological studies.

Sequencing of the Chlamydophila psittaci ompA gene reveals a new genotype, E/B, and the need for a rapid discriminatory genotyping method.

Twenty-one avian Chlamydophila psittaci isolates from different European countries were characterized using ompA restriction fragment length polymorphism, ompA sequencing, and major outer membrane protein serotyping. Results reveal the presence of a new genotype, E/B, in several European countries and stress the need for a discriminatory rapid genotyping method.

Tetracycline resistance in Chlamydia suis mediated by genomic islands inserted into the chlamydial inv-like gene.

Many strains of Chlamydia suis, a pathogen of pigs, express a stable tetracycline resistance phenotype. We demonstrate that this resistance pattern is associated with a resistance gene, tet(C), in the chlamydial chromosome. Four related genomic islands were identified in seven tetracycline-resistant C. suis strains. All resistant isolates carry the structural gene tet(C) and the tetracycline repressor gene tetR(C). The islands share significant nucleotide sequence identity with resistance plasmids carried by a variety of different bacterial species. Three of the four tet(C) islands also carry a novel insertion sequence that is homologous to the IS605 family of insertion sequences. In each strain, the resistance gene and associated sequences are recombined into an identical position in a gene homologous to the inv gene of the yersiniae. These genomic islands represent the first examples of horizontally acquired DNA integrated into a natural isolate of chlamydiae or within any other obligate intracellular bacterium.

Identification of Chlamydophila pneumoniae in an emerald tree boa, Corallus caninus.

Tissues were evaluated from emerald tree boas, Corallus caninus, from a collection in which chlamydiosis was diagnosed. To determine the strain of chlamydia infecting these snakes, tissue samples from 5 frozen snakes were tested by a quantitative TaqMan polymerase chain reaction (PCR) test and a PCR sequence analysis test. Of the 22 samples tested, 9 were categorized as either positive or weakly positive with the TaqMan test, and 6 yielded an amplicon using a serial PCR test that amplified a portion of the 23S ribosomal RNA gene. A PCR product suitable for sequencing was obtained from the heart of one of the snakes. Sequence analysis showed that the snake had been infected with Chlamydophila pneumoniae. These findings show that C. pneumoniae can infect emerald tree boas, broadening the range of reptiles known to be infected by this primarily human pathogen.

Desarrollo del plan de sistemas e información: Informe V / Plan development and information systems: Report V

El presente documento toma como punto de referencia, el plan estratégico de sistemas de información del Ministerio de Salud para el desarrollo del plan de sistemas de información