RESUMO
Eighty-five isolates of Klebsiella pneumoniae and Enterobacter spp., originating from hospital- and community-acquired infections and from oropharyngeal and faecal microbiota from patients in Recife-PE, Brazil, were analyzed regarding the presence of irp2 gene. This is a Yersinia typical gene involved in the synthesis of siderophore yersiniabactin. DNA sequencing confirmed the identity of irp2 gene in five K. pneumoniae, five Enterobacter aerogenes and one Enterobacter amnigenus isolates. To our knowledge in the current literature, this is the first report of the irp2 gene in E. amnigenus, a species considered an unusual human pathogen, and in K. pneumoniae and E. aerogenes isolates from the normal microbiota and from community infections, respectively. Additionally, the analyses of nucleotide and amino acid sequences suggest the irp2 genes derived from isolates used in this study are more closely related to that of Yersinia pestis P.CE882 than to that of Yersinia enterocolitica 8081. These data demonstrated that K. pneumoniae and Enterobacter spp. from normal microbiota and from community- and hospital-acquired infections possess virulence factors important for the establishment of extra-intestinal infections.
Assuntos
Infecções Comunitárias Adquiridas/microbiologia , Infecção Hospitalar/microbiologia , Enterobacter/genética , Infecções por Enterobacteriaceae/microbiologia , Proteína 2 Reguladora do Ferro/análise , Klebsiella pneumoniae/genética , Microbiota , Brasil , Enterobacter/isolamento & purificação , Fezes/microbiologia , Proteína 2 Reguladora do Ferro/genética , Klebsiella pneumoniae/isolamento & purificação , Orofaringe/microbiologia , Análise de Sequência de DNA , Fatores de Virulência/análise , Fatores de Virulência/genéticaRESUMO
Klebsiella pneumoniae strains can produce different virulence factors, such as fimbrial adhesins and siderophores, which are important in the colonization and development of the infection. The aims of this study were to determine the occurrence of fimH, mrkD, and irp2 virulence genes in 22 KPC-2-producing K. pneumoniae isolates as well as 22 not producing-KPC isolates, from patients from different hospitals in Recife-PE, Brazil, and also to analyze the clonal relationship of the isolates by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The genes were detected by PCR and DNA sequencing. The bla KPC-2 gene was identified in 22 KPC-positive isolates. On analyzing the antimicrobial susceptibility profile of the isolates, it was detected that polymyxin and amikacin were the antimicrobials of best activity against K. pneumoniae. On the other hand, five isolates exhibited resistance to polymyxin. In the KPC-positive group, was observed a high rate of resistance to cephalosporins, followed by carbapenems. Molecular typing by ERIC-PCR detected 38 genetic profiles, demonstrating a multiclonal spread of the isolates analyzed. It was observed that the virulence genes irp2, mrkD, and fimH were seen to have together a higher frequency in the KPC-positive group. The accumulation of virulence genes of KPC-positive K. pneumoniae isolates, observed in this study, along with the multi-resistance impose significant therapeutic limitations on the treatment of infections caused by K. pneumoniae.
Assuntos
Adesinas Bacterianas/genética , Proteínas de Fímbrias/genética , Proteína 2 Reguladora do Ferro/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Fatores de Virulência/genética , beta-Lactamases/genética , Antibacterianos/farmacologia , Brasil , Farmacorresistência Bacteriana , Genótipo , Hospitais , Humanos , Klebsiella pneumoniae/classificação , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Tipagem Molecular , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , beta-Lactamases/metabolismoRESUMO
Iron metabolism plays an important role in the pathogenesis of lung cancer. This study aimed to investigate the effect of gene silencing of iron regulatory protein-2 (IRP2) on mRNA and protein expression of transferrin (Tf), transferrin receptor (TfR), and ferritin (Fn) in A549 lung cancer cells. A549 cells were cultured and divided into a liposome control group, a liposome + oligonucleotide (SCODN) control group, and a Lipofectamine + antisense oligonucleotide (ASODN) group. RT-PCR and Western blotting were used to detect mRNA and protein expression of Tf, TfR, and Fn. We found no significant change in Tf mRNA expression among the 3 groups (P = 0.078). TfR and Fn mRNA expressions in the ASODN group notably decreased compared to the liposome and SCODN groups (P < 0.01). IRP2 and TfR protein expressions in the ASODN group were significantly lower than in the liposome or SCODN groups (P < 0.05), whereas no significant change in Tf protein expression was observed between the 3 groups (P = 0.088). Fn protein expression in the ASODN group was significantly higher than in the liposome or SCODN group (P < 0.05). IRP2 can regulate the expression of TfR and Fn by changing its own protein expression and thereby regulate iron metabolism.
Assuntos
Proteína 2 Reguladora do Ferro/genética , Ferro/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Linhagem Celular Tumoral , Ferritinas/genética , Ferritinas/metabolismo , Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Proteína 2 Reguladora do Ferro/metabolismo , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores da Transferrina/genética , Transfecção , Transferrina/genética , Transferrina/metabolismoRESUMO
Leishmania infantum infection in humans and dogs can evolve with a wide range of clinical presentations, varying from asymptomatic infections to visceral leishmaniasis. We hypothesized that the immune response elicited by L. infantum infection could modulate whether the host will remain asymptomatic or progress to disease. A total of 44 dogs naturally infected with L. infantum were studied. Leishmania burden was estimated in the blood and spleen by qPCR. The expression of IFN-γ, TNF-α, IL-10 and Iron Regulatory Protein 2 (IRP2) were determined in the spleen by quantitative PCR. Sera cytokines were evaluated by ELISA. Dogs were grouped in quartiles according parasite burden. Increased expression of IFN-γ and TNF-α was associated with reduced Leishmania burden, whereas increased IL-10 and IRP2 expressions were associated with higher Leishmania load. Increased plasma albumin and IFN-γ expression explained 22.8% of the decrease in parasite burden in the spleen. These data confirm that lower IFN-γ response and higher IL-10 correlated with increased parasite load and severity of the visceral leishmaniasis in dogs. The balance between the branches of immune response and the intracellular iron availability could determine, in part, the course of Leishmania infection.
Assuntos
Doenças do Cão/genética , Interferon gama/imunologia , Interleucina-10/imunologia , Proteína 2 Reguladora do Ferro/imunologia , Leishmania infantum/imunologia , Leishmaniose Visceral/veterinária , Animais , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Feminino , Expressão Gênica , Interações Hospedeiro-Parasita , Interferon gama/genética , Interleucina-10/genética , Ferro/imunologia , Ferro/metabolismo , Proteína 2 Reguladora do Ferro/genética , Leishmania infantum/patogenicidade , Leishmaniose Visceral/genética , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Masculino , Carga Parasitária , Albumina Sérica/imunologia , Albumina Sérica/metabolismo , Índice de Gravidade de Doença , Baço/imunologia , Baço/parasitologia , Baço/patologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
Abnormally high levels of iron are observed in the brain of patients suffering from neurodegenerative disorders. The mechanisms involved in iron accumulation in neurodegenerative disorders remain poorly understood. In the present study we investigated the effects of aging and neonatal iron overload on the mRNA expression of proteins critically involved in controlling iron homeostasis. Wistar rat pups received a single daily dose of vehicle or iron (10 mg/kg of b.w. of Fe(2+)), at postnatal days 12-14. The expression of Transferrin Receptor (TfR), H-Ferritin, and IRP2 were analyzed by a semi-quantitative reverse transcriptase polymerase chain reaction assay in cortex, hippocampus and striatum of rats sacrificed at three different ages (15-day-old; 90-day-old and 2-year old rats). Results indicate that TfR, H-ferritin, and IRP2 mRNA expression was differentially affected by aging and by neonatal iron treatment in all three brain regions. These findings might have implications for the understanding of iron homeostasis misregulation associated with neurodegenerative disorders.
Assuntos
Encéfalo/metabolismo , Homeostase , Ferro/metabolismo , Proteínas do Tecido Nervoso/genética , RNA Mensageiro/genética , Animais , Animais Recém-Nascidos , Apoferritinas/genética , Sequência de Bases , Primers do DNA , Feminino , Ferro/administração & dosagem , Proteína 2 Reguladora do Ferro/genética , Gravidez , Ratos , Ratos Wistar , Receptores da Transferrina/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Enteroaggregative Escherichia coli (EAEC) is characterized by the expression of the aggregative adherence pattern to cultured epithelial cells. In this study, we determined the phenotypic and genotypic relationships among 86 EAEC strains of human and animal (calves, piglets and horses) feces. Serotypes and the presence of EAEC virulence markers were determined, and these results were associated with ribotyping. Strains harboring aggR (typical EAEC) of human origin were found carrying several of the searched markers, while atypical EAEC harbored none or a few markers. The strains of animal origin were classified as atypical EAEC (strains lacking aggR) and harbored only irp2 or shf. Strains from humans and animals belonged to several different serotypes, although none of them prevailed. Sixteen ribotypes were determined, and there was no association with virulence genes profiles or serotypes. Relationship was not found among the strains of this study, and the assessed animals may not represent a reservoir of human pathogenic typical EAEC.