Fimbria-Encoding Gene yadC Has a Pleiotropic Effect on Several Biological Characteristics and Plays a Role in Avian Pathogenic Escherichia coli Pathogenicity.
The extraintestinal pathogen termed avian pathogenic Escherichia coli (APEC) is known to cause colibacillosis in chickens. The molecular basis of APEC pathogenesis is not fully elucidated yet. In this work, we deleted a component of the Yad gene cluster (yadC) in order to understand the role of Yad in the pathogenicity of the APEC strain SCI-07. In vitro, the transcription level of yadC was upregulated at 41°C and downregulated at 22°C. The yadC expression in vivo was more pronounced in lungs than in spleen, suggesting a role in the early steps of the infection. Chicks infected with the wild-type and mutant strains presented, respectively, 80% and 50% mortality rates. The ΔyadC strain presented a slightly decreased ability to adhere to HeLa cells with or without the d-mannose analog compared with the wild type. Real-time PCR (RT-PCR) assays showed that fimH was downregulated (P < 0.05) and csgA and ecpA were slightly upregulated in the mutant strain, showing that yadC modulates expression of other fimbriae. Bacterial internalization studies showed that the ΔyadC strain had a lower number of intracellular bacteria recovered from Hep-2 cells and HD11 cells than the wild-type strain (P < 0.05). Motility assays in soft agar demonstrated that the ΔyadC strain was less motile than the wild type (P < 0.01). Curiously, flagellum-associated genes were not dramatically downregulated in the ΔyadC strain. Taken together, the results show that the fimbrial adhesin Yad contributes to the pathogenicity and modulates different biological characteristics of the APEC strain SCI-07.
Department of Genetics, Evolution, and Bioagents, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil renuverma78@yahoo.co.in wds@unicamp.br.
Renu
R
Verma
Department of Genetics, Evolution, and Bioagents, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil.
Thaís Cabrera Galvão
TC
Rojas
Department of Genetics, Evolution, and Bioagents, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil.
Renato Pariz
RP
Maluta
Department of Genetics, Evolution, and Bioagents, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil.
Janaína Luisa
JL
Leite
Department of Genetics, Evolution, and Bioagents, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil.
Livia Pilatti Mendes
LP
da Silva
Department of Microbiology, Biological Science Center, University of Londrina-UEL, Londrina, PR, Brazil.
Gerson
G
Nakazato
Department of Genetics, Evolution, and Bioagents, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil renuverma78@yahoo.co.in wds@unicamp.br.
Wanderley
W
Dias da Silveira
D018829:Adhesins, Bacterial / Q000235:genetics*; D018830:Adhesins, Escherichia coli / Q000096:biosynthesis; D000818:Animals; D001422:Bacterial Adhesion / Q000235:genetics*; D002645:Chickens; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics*; D036781:Fimbriae Proteins / Q000096:biosynthesis / Q000235:genetics*; D010861:Fimbriae, Bacterial / Q000235:genetics*; D005407:Flagella / Q000235:genetics; D055786:Gene Knockout Techniques; D006367:HeLa Cells; D006801:Humans; D008168:Lung / Q000382:microbiology; D011201:Poultry Diseases / Q000382:microbiology; D013154:Spleen / Q000382:microbiology
D018829:Adhesins, Bacterial; D018830:Adhesins, Escherichia coli; C571837:EcpA protein, E coli; D029968:Escherichia coli Proteins; C000607816:YadC protein, E coli; C489688:csgA protein, E coli; C058769:fimH protein, E coli; D036781:Fimbriae Proteins