RESUMO
While alternating between insects and mammals during its life cycle, Yersinia pestis, the flea-transmitted bacterium that causes plague, regulates its gene expression appropriately to adapt to these two physiologically disparate host environments. In fleas competent to transmit Y. pestis, low-GC-content genes y3555, y3551, and y3550 are highly transcribed, suggesting that these genes have a highly prioritized role in flea infection. Here, we demonstrate that y3555, y3551, and y3550 are transcribed as part of a single polycistronic mRNA comprising the y3555, y3554, y3553, y355x, y3551, and y3550 genes. Additionally, y355x-y3551-y3550 compose another operon, while y3550 can be also transcribed as a monocistronic mRNA. The expression of these genes is induced by hyperosmotic salinity stress, which serves as an explicit environmental stimulus that initiates transcriptional activity from the predicted y3550 promoter. Y3555 has homology to pyridoxal 5'-phosphate (PLP)-dependent aromatic aminotransferases, while Y3550 and Y3551 are homologous to the Rid protein superfamily (YjgF/YER057c/UK114) members that forestall damage caused by reactive intermediates formed during PLP-dependent enzymatic activity. We demonstrate that y3551 specifically encodes an archetypal RidA protein with 2-aminoacrylate deaminase activity but Y3550 lacks Rid deaminase function. Heterologous expression of y3555 generates a critical aspartate requirement in a Salmonella entericaaspC mutant, while its in vitro expression, and specifically its heterologous coexpression with y3550, enhances the growth rate of an Escherichia coli ΔaspC ΔtyrB mutant in a defined minimal amino acid-supplemented medium. Our data suggest that the y3555, y3551, and y3550 genes operate cooperatively to optimize aromatic amino acid metabolism and are induced under conditions of hyperosmotic salinity stress.IMPORTANCE Distinct gene repertoires are expressed during Y. pestis infection of its flea and mammalian hosts. The functions of many of these genes remain predicted or unknown, necessitating their characterization, as this may provide a better understanding of Y. pestis specialized biological adaptations to the discrete environments of its two hosts. This study provides functional context to adjacently clustered horizontally acquired genes predominantly expressed in the flea host by deciphering their fundamental processes with regard to (i) transcriptional organization, (ii) transcription activation signals, and (iii) biochemical function. Our data support a role for these genes in osmoadaptation and aromatic amino acid metabolism, highlighting these as preferential processes by which Y. pestis gene expression is modulated during flea infection.
Assuntos
Aminoácidos Aromáticos/metabolismo , Sifonápteros/microbiologia , Yersinia pestis/metabolismo , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Transferência Genética Horizontal , Óperon , Yersinia pestis/genética , Yersinia pestis/crescimento & desenvolvimentoRESUMO
Francisellosis is a disease caused by different species of the bacterial genus Francisella and has been diagnosed in a wide variety of animals, including fish. Francisellosis in fish is characterized by the development of non-specific clinical signs as well as the presence of numerous granulomas in several organs (mainly spleen and kidney). Ten neon jewel cichlids Hemichromis bimaculatus were submitted for diagnosis from a farm located in Morelos, Mexico. Gross examination, wet preparations, cytology, histopathology and PCR were performed. Affected fish showed lethargy, erratic swimming, imbalance and gasping. At the post mortem examination, multiple granulomas were observed in the kidney and spleen. Microscopically, granulomatous inflammation was observed in several organs. Species-specific PCR assay using DNA from the affected tissues of H. bimaculatus as a template demonstrated the presence of F. noatunensis subsp. orientalis (Fno) by amplifying a hypothetical protein gene of the Fno species. The end diagnosis of francisellosis is important for Mexican ornamental aquaculture, since it is necessary to implement measures for treatment, prevention, control and diagnosis. This is the first report of francisellosis in the neon jewel cichlid.
Assuntos
Ciclídeos , Doenças dos Peixes , Francisella , Infecções por Bactérias Gram-Negativas , Animais , Surtos de Doenças , MéxicoRESUMO
Background: Coxiella burnetii, an obligate intracellular bacterium, is the etiological agent of Q fever in humans and one of the causes of abortion in small ruminants. Although coxiellosis is considered an exotic disease, there are a few reports in Mexico. Methods: The objective of this work was to determine the presence of C. burnetii DNA in vaginal samples from sheep that presented abortion and ram semen. A total of 180 vaginal exudate samples and 20 semen samples were obtained from five Central and Southern States of Mexico. Total DNA was extracted from vaginal swabs and C. burnetii was identified by PCR amplification and sequencing of the IS1111 insertion sequence. Results and Conclusion: In total, 110 (110/180) vaginal samples and 12 (12/20) semen samples were positive for C. burnetii. This is the first report of C. burnetii in sheep that aborted and in ram semen in Mexico.
RESUMO
INTRODUCTION: Mycetoma is a chronic granulomatous inflammatory disease of the subcutaneous tissue, which affects deep structures and bone. Most cases of actinomycetoma are caused by members of the genus Nocardia. CASE PRESENTATION: Here we report the case of a 43-year-old male who presented a disseminated mycetoma on the forearm, chest and neck, characterized by enlarged and erythematous lesions through which seropurulent material drains, and numerous atrophic scars. Molecular identification was performed by 16S gene amplification and sequencing. Nocardia mexicana was identified with 100% identity. Trimethoprim-sulfamethoxazole, diaminodiphenyl sulfone and amikacin was a successful treatment after 6 months. CONCLUSIONS: Nocardia mexicana is a rare organism that causes mycetoma. We report a case of extensive mycetoma on the forearm with spread to the neck and thorax associated with manipulation of the mouth of a calf.
Assuntos
Antibacterianos , Antebraço , Micetoma , Pescoço , Nocardiose , Nocardia , RNA Ribossômico 16S , Tórax , Humanos , Masculino , Adulto , Nocardia/isolamento & purificação , Nocardia/genética , Micetoma/microbiologia , Micetoma/tratamento farmacológico , Micetoma/diagnóstico , Nocardiose/microbiologia , Nocardiose/tratamento farmacológico , Nocardiose/diagnóstico , Antebraço/microbiologia , Antebraço/patologia , Tórax/diagnóstico por imagem , Tórax/microbiologia , Pescoço/patologia , Antibacterianos/uso terapêutico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , DNA Bacteriano/genética , Resultado do Tratamento , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Amicacina/uso terapêutico , DNA Ribossômico/genética , DNA Ribossômico/químicaRESUMO
Chromoblastomycosis is a chronic subcutaneous mycosis caused by traumatic inoculation of dematiaceous fungi especially in tropical and subtropical areas. Cyphellophora genus include melanized fungi reported as etiological agents of skin and nail infections. We report a 60-year-old male from the south of Mexico with a 40-year history of chromoblastomycosis caused by Cyphellophora laciniata. The isolated fungus was identified by sequencing of the internal transcribed spacer region of rDNA. The patient was treated with itraconazole and cryosurgery with unsatisfactory results.
Assuntos
Ascomicetos , Cromoblastomicose , Antifúngicos/uso terapêutico , Ascomicetos/genética , Cromoblastomicose/diagnóstico , Cromoblastomicose/tratamento farmacológico , Cromoblastomicose/microbiologia , Humanos , Itraconazol/uso terapêutico , Masculino , Pessoa de Meia-IdadeRESUMO
Bovine mastitis, an inflammation of the mammary gland of dairy cattle, is the most prevalent disease causing economically important losses, reduced milk production, early culling, veterinary expenses, and higher death rates. Bovine mastitis infections are the main cause for the use of antibiotics; however, the emergence of multidrug-resistant bacteria and the poor or nil response to antibiotics has become a critical global health problem. The goal of this study was the characterization of bacterial infections associated with clinical bovine mastitis. All the isolates were multidrug-resistant and were negative for the production of extended spectrum ß-lactamases. However, all isolates were identified as carbapenemase-producing organisms by the Carba NP test. The carbapenemase identified was the product of the KPC-2 gene. The isolates were identified as Klebsiella pneumoniae and contained virulence genes for fimbriae, lipopolysaccharides, nitrogen starvation genes, and siderophores. Sixty-nine percent of the KPC-2-producing isolates had the same plasmid profile, although the genetic mobilization of resistance by bacterial conjugation was unsuccessful. The carbapenemase corresponded to the plasmid-borne KPC-2 gene identified by Southern blot hybridization. The assay showed a positive signal in the 90 kb (69% of the isolates), 165 kb (31% of the isolates), and 130 kb (6% of the isolates) plasmids. The IncFIIy and IncFIIk replicons were detected among these K. pneumoniae isolates. The PFGE and MLST analysis showed that all of the isolates are comprised by two clones (A and B) belonging to Sequence Type 258. This is the first report of K. pneumoniae producing carbapenemase KPC-2 isolated from bovine mastitis.
Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Infecções por Klebsiella/veterinária , Klebsiella pneumoniae/isolamento & purificação , Mastite Bovina/microbiologia , beta-Lactamases/metabolismo , Animais , Antibacterianos/farmacologia , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriáceas Resistentes a Carbapenêmicos/enzimologia , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Bovinos , Farmacorresistência Bacteriana Múltipla , Feminino , Genótipo , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Virulência/genética , beta-Lactamases/genéticaRESUMO
Chromoblastomycosis is a chronic subcutaneous fungal infection caused by melanized fungi. It is usually an occupational mycosis affecting people in rural areas in tropical and subtropical regions. We present two cases of chromoblastomycosis in Mexican farmers, characterized by skin verrucous plaques. Direct examination with KOH 10% showed the presence of muriform cells. The fungal isolation was carried out in Sabouraud dextrose agar and molecular identification was achieved by 18S-ITS1-5.8S-ITS2-28S rRNA gene amplification and sequencing. Fonsecaeamonophora was identified in both cases. A therapy with itraconazole and terbinafine was used with a partial favorable response. However, patients did not return for medical examination after 4 months. The current status of the patients is unknown. We reported the first two cases of chromoblastomycosis caused by F. monophora in Mexico.
Assuntos
Antifúngicos/farmacologia , Cromoblastomicose/diagnóstico , Fonsecaea/efeitos dos fármacos , Fonsecaea/genética , Pele/microbiologia , Adulto , Idoso , Antifúngicos/uso terapêutico , Cromoblastomicose/tratamento farmacológico , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Fazendeiros , Fonsecaea/classificação , Fonsecaea/patogenicidade , Humanos , Masculino , México , Testes de Sensibilidade Microbiana , Análise de Sequência de DNA , Pele/patologiaRESUMO
Yersinia pestis, responsible for causing fulminant plague, has evolved clonally from the enteric pathogen, Y. pseudotuberculosis, which in contrast, causes a relatively benign enteric illness. An ~97% nucleotide identity over 75% of their shared protein coding genes is maintained between these two pathogens, leaving much conjecture regarding the molecular determinants responsible for producing these vastly different disease etiologies, host preferences and transmission routes. One idea is that coordinated production of distinct factors required for host adaptation and virulence in response to specific environmental cues could contribute to the distinct pathogenicity distinguishing these two species. Small non-coding RNAs that direct posttranscriptional regulation have recently been identified as key molecules that may provide such timeous expression of appropriate disease enabling factors. Here the burgeoning field of small non-coding regulatory RNAs in Yersinia pathogenesis is reviewed from the viewpoint of adaptive colonization, virulence and divergent evolution of these pathogens.