Margarita María de la Paz Arenas-Hernández

Uropathogenic Escherichia coli (UPEC) causes urinary tract infections worldwide. We report the draft genomes of three UPEC strains from Mexican patients. The genomes ranged from 5.05 to 5.81 Mb, with 50.0–50.5% guanine-cytosine content and 4,960–6,013 predicted genes.

There has been an increasing number of global reports documenting the high prevalence of multidrug-resistant (MDR) strains in the environment, highlighting the role of food as a reservoir of both commensal and pathogenic Escherichia coli capable of harboring and transmitting antimicrobial resistance genes. Fresh vegetables can become contaminated with bacteria during production, handling, and distribution and may consequently harbor substantial bacterial loads. Because these products are often consumed raw or with minimal processing, inadequate washing and disinfection practices may allow bacteria to persist on their surfaces, including MDR strains. The presence of antimicrobial-resistant E. coli in ready-to-eat vegetables is of concern because these bacteria may harbor virulence and antimicrobial resistance determinants, as well as mobile genetic elements that facilitate their dissemination. Consequently, characterization of their resistome, virulome, and plasmidome can provide comprehensive insights into their pathogenic potential, resistance profiles, and the genetic mechanisms that may contribute to the spread of antimicrobial resistance along the food chain. This study focuses on two E. coli strains, A65EC and A134EC, isolated from ready-to-eat cilantro. Both strains were phenotypically characterized as MDR and AmpC-type β-lactamase producers, a capacity associated with the presence of the blaCMY-2 gene on an IncI1 and p0111 plasmid, respectively. In addition, A65EC belonging to ST746 presented three additional plasmids characterized as conjugative or mobilizable, harboring the resistance genes aadA2, blaTEM-103, sul1, dfrA12, dfrA14, tetA and qacEΔ1. Meanwhile, A134EC corresponding to ST10 showed three conjugative plasmids and one mobilizable plasmid carrying the genes aadA5, aac(3)-Ild, dfrA17, qacEΔ1, sul3, mefB, floR, estT and fosA2. Moreover, 19 virulence genes were identified, of which nine (aslA, fimH, nlpl, iss, sitA, terC, hlyE, cia, and anr) were shared by both strains. This is the first report of blaCMY-2-bearing strains isolated from green leafy vegetables, and we describe the presence of the fosA2 gene harbored on a conjugative plasmid. The detection of multidrug-resistant strains with the genetic potential to transfer resistance determinants in fresh produce is a concerning finding. It underscores the urgent need for surveillance and monitoring systems in vegetables to better elucidate the transmission pathways of resistance and virulence genes across diverse ecological niches.

An increasing number of global reports on the high prevalence of multidrug-resistant (MDR) strains in the environment underscoring the role of food as a reservoir for both commensal and pathogenic Escherichia coli capable of transmitting drug resistance genes. Due to how they are consumed and the possibility of poor washing and disinfection processes, vegetables have been frequently associated with the presence of multidrug-resistant strains. This study describes the resistome, virulome, and plasmidome of E. coli strains A65EC and A134EC that were isolated from ready-to-eat cilantro. Both strains were phenotypically characterized as MDR and AmpC-type β-lactamase producers, a capacity associated with the presence of the blaCMY-2 gene on an IncI1 and p0111 plasmid, respectively. In addition, A65EC belonging to ST746 presented three additional plasmids characterized as conjugative or mobilizable, harboring the resistance genes aadA2, blaTEM-103, sul1, dfrA12, dfrA14, tetA and qacEΔ1. Meanwhile, A134EC corresponding to ST10 showed three conjugative plasmids and one mobilizable plasmid carrying the genes aadA5, aac(3)-Ild, dfrA17, qacEΔ1, sul3, mefB, floR, estT and fosA2. described19 virulence genes were described, of which nine (aslA, fimH, nlpl, iss, sitA, terC, hlyE, cia, and anr) were shared in both strains. This is the first report of blaCMY-2-bearing strains isolated from green leafy vegetables, and we describe the presence of the fosA2 gene harbored on a conjugative plasmid. The detection of multidrug-resistant strains with the genetic potential to transfer resistance determinants in fresh produce is a concerning finding. It underscores the urgent need for surveillance and monitoring systems in vegetables to better elucidate the transmission pathways of resistance and virulence genes across diverse ecological niches.

Species outside the Acinetobacter calcoaceticus–baumannii (Acb) complex have recently emerged as new clinically relevant carbapenem-resistant pathogens, such as A. haemolyticus . A new mechanism that could contribute to the dissemination of this resistance is the secretion of outer membrane vesicles (OMVs). We investigate OMVs secreted by A. haemolyticus AN54, a Mexican clinical strain carrying a plasmid-borne bla _NDM−1 gene and by its plasmid-cured derivative AN54Δe. Active secretion of OMVs formed by a lipid membrane, measuring 10–50 nm in both strains, was observed by TEM. The OMVs from AN54 possess hydrolytic capacity against carbapenem. The OMV protein profile varied depending on the antibiotic concentration during induction, with additional protein bands detected at 8 and 32 µg/ml of antibiotic exposure. Mass spectrometry identified proteins involved in different metabolic pathways and in resistance-related processes. The porins, efflux pumps, and ADC enzyme were more abundant in the OMVs from AN54Δe than in those from AN54 harboring the active NDM-1 enzyme. The OMVs protected the sensitive strains from the same and different genera against the antibiotic action for a limited period. However, the OMVs transferred the bla _NDM−1 -carrying plasmid (pAhaeAN54e) only to the AN54Δe strain, conferring permanent resistance to carbapenems. Together, these findings suggest that OMVs can help protect surrounding bacteria from antibiotic action and serve as vehicles for disseminating resistance genes. These results show the importance of studying OMVs as a novel mechanism for the dissemination of antimicrobial resistance.

Los antimicrobianos son medicamentos que desde su introducción a la clínica han permitido extender la esperanza de vida, ya que combaten las enfermedades infecciosas y minimizan su aparición durante procesos quirúrgicos. La interacción entre el antimicrobiano y los componentes del microorganismo se debe a la química y estructura de la molécula, permitiendo así la interferencia o modificación de los procesos vitales de los microorganismos. A lo largo de los años un número importante de antimicrobianos han sido introducidos a la práctica clínica debido a la creciente resistencia que adquieren o desarrollan los patógenos por el uso inapropiado de estos compuestos por parte del personal de salud y consumidores. Este proceso se ha llevado a cabo mediante el descubrimiento de nuevos compuestos naturales, sintéticos y semisintéticos, a través de la modificación de los radicales del núcleo farmacóforo (semi sintéticos), permitiendo así mejorar sus características farmacológicas y elevar la población microbiana susceptible. Con base en lo anterior, esta revisión expone la estructura química y los principales grupos de antimicrobianos que actualmente se emplean, con el fin de proporcionarle al lector una guía concisa y de fácil acceso a las características generales de los fármacos, dándole así, un panorama general que le permita entender situaciones que involucren su uso.

Las infecciones del tracto urinario (ITU) son de las más comunes y recurrentes que afectan a hombres y mujeres a cualquier edad. Asimismo, representan un problema de salud pública a nivel mundial. El agente etiológico principal es Escherichia coli uropatógena (UPEC), bacteria presente en más del 80% de las ITU adquiridas en la comunidad. A la fecha, varios autores han contribuido con estudios que describen los factores de virulencia que capacitan a Escherichia coli uropatógena para producir ITU. Sin embargo, lo que se sabe de la genética de este patógeno se encuentra restringido a un número limitado de genes que han servido para su clasificación como son los que codifican para diversos factores de virulencia, que no son compartidos por la totalidad de las Escherichia coli uropatógenas. Por ello, el objetivo de esta revisión es conocer el impacto que el análisis de la secuenciación del genoma completo ha tenido para entender el papel de UPEC como patógeno y como un complemento de otros estudios.

The present study shows the genomic characterization of three pathogenic Escherichia coli hybrid strains. All strains were previously characterized as diarrheagenic pathotypes (DEC), obtained from feces. The three sequenced strains have genes that encode adhesins (fimH and iha) and iron uptake systems (iucC and iutA). Antibiotic resistance genes were also found for fluoroquinolone and aminoglycoside families in the three strains. The presence of genomic islands (GIs) in the sequenced study strains presented 100% identity (Ec-25.2) and 99% identity (Ec-36.1) with previously reported Extraintestinal Pathogenic E. coli (ExPEC) strains. The Ec-36.4 strain shared a 99% identity with GI from the Enterotoxigenic E. coli (ETEC) pathotype of the diarrheagenic E. coli strain. Ec-25.2 belongs to ST69 and harbors a FimH27 variant, while Ec-36.1 and Ec-36.4 belong to ST4238 and share a FimH54 variant. Four incompatibility groups associated with conjugative plasmids were identified (IncFIB, IncF11, IncI1, and IncB/O/K/Z), as well as Insertion Sequences and MITEs elements.

Uropathogenic Escherichia coli (UPEC) remains the main etiological agent of urinary tract infections affecting females and males. The draft genome sequence of three strains of UPEC isolated from senior citizens and pregnant women in the state of Puebla, Mexico, is reported here.

Uropathogenic Escherichia coli (UPEC) is the main cause of urinary tract infections (UTIs) and carries virulence and resistance factors often found in mobilizable genetic elements, such as plasmids or pathogenicity islands (PAIs). UPEC is part of the extraintestinal pathogenic E. coli (ExPEC), but hybrid strains possessing both diarrheagenic E. coli (DEC) and ExPEC traits, termed “hypervirulent”, present a significant health threat. This study assessed the prevalence of UPEC PAIs, ExPEC sequence types (ST), DEC genes, carbapenemase and extended-spectrum β-lactamase (ESBL) phenotypes, resistance genotypes, and plasmids in 40 clinical isolates of UPEC. Results showed that 72.5% of isolates had PAIs, mainly PAI IV₅₃₆ (53%). ESBL phenotypes were found in 65% of β-lactam-resistant isolates, with 100% of carbapenem-resistant isolates producing carbapenemase. The predominant ESBL gene was bla_CTX-M-2 (60%), and the most common resistance gene in fluoroquinolone and aminoglycoside-resistant isolates was aac(6′)Ib (93%). Plasmids were present in 57% of isolates, and 70% belonged to the ST131 clonal group. Molecular markers for DEC pathotypes were detected in 20 isolates, with 60% classified as hybrid pathotypes. These findings indicate significant pathogenic potential and the presence of hybrid pathotypes in E. coli UTI clinical isolates in the Mexican population.