The Assembly of Flagella in Enteropathogenic Escherichia coli Requires the Presence of a Functional Type III Secretion System

In enteropathogenic Escherichia coli (EPEC), the production of flagella and the type III secretion system (T3SS) is activated in the presence of host cultured epithelial cells. The goal of this study was to investigate the relationship between expression of flagella and the T3SS. Mutants deficient in assembling T3SS basal and translocon components (ΔespA, ΔespB, ΔespD, ΔescC, ΔescN, and ΔescV), and in secreting effector molecules (ΔsepD and ΔsepL) were tested for flagella production under several growth conditions. The ΔespA mutant did not produce flagella in any condition tested, although fliC was transcribed. The remaining mutants produced different levels of flagella upon growth in LB or in the presence of cells but were significantly diminished in flagella production after growth in Dulbecco’s minimal essential medium. We also investigated the role of virulence and global regulator genes in expression of flagella. The ΔqseB and ΔqseC mutants produced abundant flagella only when growing in LB and in the presence of HeLa cells, indicating that QseB and QseC act as negative regulators of fliC transcription. The ΔgrlR, ΔperA, Δler, Δhns, and Δfis mutants produced low levels of flagella, suggesting these regulators are activators of fliC expression. These data suggest that the presence of an intact T3SS is required for assembly of flagella highlighting the existence in EPEC of a cross-talk between these two virulence-associated T3SSs. © 2022 by the authors.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Lidocaína endovenosa como coadyuvante en el tratamiento inicial de la neuralgia postherpética: Bases fisiopatológicas del uso de anestésicos locales en el tratamiento del dolor neuropático

Introduction: Post-herpetic neuralgia is the algic condition that remains when the vesicles of an acute episode of herpes zoster have disappeared after a minimum period of 8-12 weeks. Up to 50% of patients older than 70 years will develop this condition after an acute episode of herpes zoster. Its physiopathological basis is still unclear, so its prevention is difficult and its treatment is aimed to symptoms. Materials and methods: One hundred patients were randomized to one of the study groups (n = 25): group A1, patients 70 years of age treated with gabapentin and endovenous lidocaine; group B2, patients > 70 years of age treated with gabapentin and endovenous lidocaine. Pain reported by the patient was assessed at four time points during the first four weeks. Results: Statistically significant differences were observed (p < 0,05) in the mean VAS scores reported by the patients, with a lower VAS score within the groups treated with endovenous lidocaine and in patients < 70 years of age in both groups. Conclusions: The treatment of post-herpetic neuralgia is aimed to symptoms. Local anesthetics have been successfully used for some types of neuropathic pain. Endovenous lidocaine can be useful as co-adjuvant during the initial treatment of post-herpetic neuralgia, since it significantly reduces the VAS score reported by patients. Aged patients had a poorer response to the use of lidocaine, as well as lower mean VAS scores, compared to patients that did not received lidocaine.Introducción: La neuralgia postherpética es el cuadro álgico que permanece tras desaparecer las vesículas del episodio agudo del herpes zóster, habiendo pasado un periodo mínimo de tiempo de 8-12 semanas. Hasta un 50% de los pacientes con edad superior a 70 años, lo desarrollará tras el episodio agudo de herpes zóster. Sus bases fisiopatológicas no han sido aclaradas, por lo que su prevención es difícil y su tratamiento sintomático. Material y métodos: Se estudiaron 100 pacientes incluidos de forma aleatoria en uno de los grupos diseñados (n = 25): grupo A1, pacientes menores de 70 años, tratados con gabapentina a dosis crecientes; grupo A2, pacientes mayores de 70 años, tratados con gabapentina a dosis crecientes; grupo B1, pacientes menores de 70 años tratados con gabapentina y lidocaína endovenosa; grupo B2, pacientes mayores de 70 años tratados con gabapentina y lidocaína endovenosa. Se evaluó el dolor referido por el paciente en cuatro momentos a lo largo de las cuatro primeras semanas. Resultados: Se observaron diferencias estadísticamente significativas, p < 0,05, en las medias de EVA referido por los pacientes, presentando una EVA menor los grupos tratados con lidocaína endovenosa y pacientes menores de 70 años en ambos grupos. Conclusiones: El tratamiento de la neuralgia postherpética es un tratamiento sintomático. Los anestésicos locales han sido utilizados con éxito en algunos tipos de dolor neuropático. La lidocaína endovenosa puede ser útil como coadyuvante en el periodo inicial del tratamiento de la neuralgia posthetpética, al reducir significativamente la EVA referida por los pacientes. Los pacientes de edad avanzada respondieron peor al uso de lidocaína, aunque presentaron medias de EVA inferiores a los pacientes a los que no se administró lidocaína

The Flp type IV pilus operon of Mycobacterium tuberculosis is expressed upon interaction with macrophages and alveolar epithelial cells

The genome of Mycobacterium tuberculosis (Mtb) harbors the genetic machinery for assembly of the Fimbrial low-molecular-weight protein (Flp) type IV pilus. Presumably, the Flp pilus is essential for pathogenesis. However, it remains unclear whether the pili genes are transcribed in culture or during infection of host cells. This study aimed to shed light on the expression of the Flp pili-assembly genes (tadZ, tadA, tadB, tadC, flp, tadE, and tadF) in Mtb growing under different growth conditions (exponential phase, stationary phase, and dormancy NRP1 and NRP2 phases induced by hypoxia), during biofilm formation, and in contact with macrophages and alveolar epithelial cells. We found that expression of tad/flp genes was significantly higher in the stationary phase than in exponential or NRP1 or NRP2 phases suggesting that the bacteria do not require type IV pili during dormancy. Elevated gene expression levels were recorded when the bacilli were in contact for 4 h with macrophages or epithelial cells, compared to mycobacteria propagated alone in the cultured medium. An antibody raised against a 12-mer peptide derived from the Flp pilin subunit detected the presence of Flp pili on intra- and extracellular bacteria infecting eukaryotic cells. Altogether, these are compelling data showing that the Flp pili genes are expressed during the interaction of Mtb with host cells and highlight a role for Flp pili in colonization and invasion of the host, subsequently promoting bacterial survival during dormancy. Copyright © 2022 Alteri, Rios-Sarabia, De la Cruz, González-y-Merchand, Soria-Bustos, Maldonado-Bernal, Cedillo, Yáñez-Santos, Martínez-Laguna, Torres, Friedman, Girón and Ares.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]