Periodontitis exacerbation during pregnancy in mice: Role of macrophage migration inhibitory factor as a key inductor.

OBJECTIVE: The present study was designed to investigate the role of macrophage migration inhibitory factor (MIF) in the exacerbation of pregestational periodontal disease (PGPD). BACKGROUND: Periodontitis (PT) is a severe stage of periodontal disease characterized by inflammation of the supporting tissues of the teeth, which usually worsens during pregnancy. MIF is a proinflammatory cytokine that is significantly elevated in periodontitis, both at the beginning and at the end of pregnancy. Although periodontitis usually presents with greater severity during pregnancy, the participation of MIF in the evolution of periodontitis has not been established. METHODS: To analyze the relevance of MIF in the exacerbation of PGPD, we employed a model of PGPD in WT and Mif-/- mice, both with a BALB/c genetic background. PT was induced with nylon suture ligatures placed supramarginally around the second upper right molar. For PGPD, PT was induced 2 weeks before mating. We evaluated histological changes and performed histometric analysis of the clinical attachment loss, relative expression of MMP-2 and MMP-13 by immunofluorescence, and relative expression of the cytokines mif, tnf-α, ifn-γ, and il-17 by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: Our data revealed that periodontal tissue from PGPD WT mice produced a twofold increase in MIF compared with PT WT mice. Moreover, the evolution of periodontitis in Mif-/- mice was less severe than in PGDP WT mice. Periodontal tissue from Mif-/- mice with PGPD produced 80% less TNF-α and no IFN-γ, as well as 50% lower expression of matrix metalloproteinase (MMP)-2 and 25% less MMP-13 compared to WT PGDP mice. CONCLUSIONS: Our study suggests that MIF plays an important role in the exacerbation of periodontitis during pregnancy and that MIF is partially responsible for the inflammation associated with the severity of periodontitis during pregnancy.

Extensive Expression of the Virulome Related to Antibiotic Genotyping in Nosocomial Strains of Klebsiella pneumoniae.

The emergence of hyper-virulent and multidrug-resistant (MDR) strains of Klebsiella pneumoniae isolated from patients with hospital- and community-acquired infections is a serious health problem that increases mortality. The molecular analysis of virulome expression related to antimicrobial-resistant genotype and infection type in K. pneumoniae strains isolated from patients with hospital- and community-acquired infections has been poorly studied. In this study, we analyzed the overall expression of the virulence genotype associated with the antimicrobial resistance genotype and pulse field gel electrophoresis (PFGE) type (PFtype) in K. pneumoniae. We studied 25 strains of K. pneumoniae isolated from patients who developed bacteremia and pneumonia during their hospital stay and 125 strains from outpatients who acquired community-acquired infections. Susceptibility to 12 antimicrobials was determined by Kirby-Bauer. The identification of K. pneumoniae and antibiotic-resistance genes was performed using polymerase chain reaction (PCR). To promote the expression of the virulence genes of K. pneumoniae, an in vitro infection model was used in human epithelial cell lines A549 and A431. Bacterial RNA was extracted with the QIAcube robotic workstation, and reverse transcription to cDNA was performed with the Reverse Transcription QuantiTect kit (Qiagen). The determination of the expression of the virulence genes was performed by real-time PCR. In addition, 57.3% (n = 86) of the strains isolated from patients with hospital- and community-acquired infections were multidrug-resistant (MDR), mainly to beta-lactam antibiotics (CB, AM, CFX, and CF), aminoglycosides (GE), quinolones (CPF and NOF), nitrofurantoin (NF), and sulfamethoxazole/trimethoprim (SXT). The most frequently expressed genes among strains isolated from hospital- and community-acquired infections were adhesion-type, ycfm (80%), mrkD (51.3%), and fimH (30.7%); iron uptake, irp2 (84%), fyuA (68.7%), entB (64.7%), and irp1 (56.7%); and protectins, rpmA (26%), which were related to antibiotic-resistance genes, blaTEM (96%), blaSHV (64%), blaCITM (52.6%), blaCTXM-1 (44.7%), tetA (74%), sul1 (57.3%), aac(3)-IV (40.7%), and aadA1 (36%). The results showed the existence of different patterns of expression of virulome related to the genotype of resistance to antimicrobials and to the PFtypes in the strains of K. pneumoniae that cause hospital- and community-acquired infections. These findings are important and may contribute to improving medical treatment strategies against infections caused by K. pneumoniae.

Hypervirulence and Multiresistance to Antibiotics in Klebsiella pneumoniae Strains Isolated from Patients with Hospital- and Community-Acquired Infections in a Mexican Medical Center.

Klebsiella pneumoniae is a pathogenic bacterium associated with different infectious diseases. This study aimed to establish the different association profiles of virulence genes related to the hypermucoviscous phenotype (HM), capsular serotypes, biofilm formation, and multidrug resistance in K. pneumoniae strains from patients with hospital- and community-acquired infections. K. pneumoniae virulence genes and capsular serotypes were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, HM by the string test, and biofilm formation by measurement in polystyrene microtiter plates. Of a total of 150 strains from patients with hospital- (n = 25) and community-acquired infections (n = 125), 53.3% (80/150) were HM-positive and 46.7% (70/150) were HM-negative. HM-positive (68/80) and HM-negative (67/70) strains were biofilm-forming. Moreover, 58.7% (47/80) HM-positive and 57.1% (40/70) HM-negative strains were multidrug-resistant. Among HM-positive, HM-negative, and serotypes K1 (25/150), K2 (48/150), and non-K1/K2 strains, (77/150) the frequently detected adhesion genes were fimH, mrkD, ycfM, and kpn; entB, irp2, irp1, and ybtS, for iron acquisition; and rmpA for protectins. The gene association pattern fimH/kpn/mrkD/ycfM/entB/irp1/irp2/ybtS/fyuA (18/150) was frequent among the strains. K. pneumoniae strains from patients with hospital- and community-acquired infections demonstrated a wide diversity of virulence gene profiles related to phenotype (hypermucoviscosity, multidrug resistance, and biofilm formation) and serotypes.

High Virulence and Multidrug Resistance of Escherichia coli Isolated in Periodontal Disease.

Periodontal disease is caused by different gram-negative anaerobic bacteria; however, Escherichia coli has also been isolated from periodontitis and its role in periodontitis is less known. This study aimed to determine the variability in virulence genotype, antibiotic resistance phenotype, biofilm formation, phylogroups, and serotypes in different emerging periodontal strains of Escherichia coli, isolated from patients with periodontal disease and healthy controls. E. coli, virulence genes, and phylogroups, were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, biofilm formation was quantified using polystyrene microtiter plates, and serotypes were determined by serotyping. Although E. coli was not detected in the controls (n = 70), it was isolated in 14.7% (100/678) of the patients. Most of the strains (n = 81/100) were multidrug-resistance. The most frequent adhesion genes among the strains were fimH and iha, toxin genes were usp and hlyA, iron-acquisition genes were fyuA and irp2, and protectin genes were ompT, and KpsMT. Phylogroup B2 and serotype O25:H4 were the most predominant among the strains. These findings suggest that E. coli may be involved in periodontal disease due to its high virulence, multidrug-resistance, and a wide distribution of phylogroups and serotypes.

Frequency and expression of genes involved in adhesion and biofilm formation in Staphylococcus aureus strains isolated from periodontal lesions.

BACKGROUND/PURPOSE: The aim of this study was to characterize the Staphylococcus aureus strains isolated from periodontal lesions of patients, to determine the expression of genes involved in cell adhesion upon their infection of human epithelial cells using an in vitro model, its biofilm formation, and its resistance to antibiotics. METHODS: S. aureus was analysed by PCR, Kirby-Bauer, and pulsed-field gel electrophoresis (PFGE), measuring gene expression by real-time PCR after infection of human cells in vitro. RESULTS: S. aureus was identified in 18.6% (50/268) of the samples. All strains (n = 50) possessed the virulence genes spa (Staphylococcal protein A), coa (coagulase), and icaAB (intercellular adhesin); 96% (n = 48) possessed clfB (clumping factor B), and 88% (n = 44) possessed ebps (elastin-binding protein) and sdrD (serine aspartate repeat protein D). All strains were resistant to methicillin, ampicillin, dicloxacillin, cefotaxime, and penicillin, and were multidrug resistant to 6-12 antibiotics. PFGE analysis showed 37 different pulsed-field types and most strains (60.4%) had a unique pulsed-field type. Twenty-four distinct combinations of virulence genes and antibiotic-resistant phenotypes were identified. CONCLUSION: Although S. aureus has been considered a transient member of the oral microbiota, our results indicate a high-level expression of virulence genes and multidrug resistance in the strains isolated from periodontal lesions. These strains might complicate the successful treatment of the disease.

Synaptotagmin-1 membrane binding is driven by the C2B domain and assisted cooperatively by the C2A domain.

Synaptotagmin interaction with anionic lipid (phosphatidylserine/phosphatidylinositol) containing membranes, both in the absence and presence of calcium ions (Ca2+), is critical to its central role in orchestrating neurotransmitter release. The molecular surfaces involved, namely the conserved polylysine motif in the C2B domain and Ca2+-binding aliphatic loops on both C2A and C2B domains, are known. Here we use surface force apparatus combined with systematic mutational analysis of the functional surfaces to directly measure Syt1-membrane interaction and fully map the site-binding energetics of Syt1 both in the absence and presence of Ca2+. By correlating energetics data with the molecular rearrangements measured during confinement, we find that both C2 domains cooperate in membrane binding, with the C2B domain functioning as the main energetic driver, and the C2A domain acting as a facilitator.

Using 6 Degrees of Freedom to Systematically Reduce and Fix Distal Radius Fractures.

Six degrees of freedom (6DOF) refers to the freedom of movement of a rigid body in 3-dimensional space. Specifically, the object can move in 3 translations: up/down, left/right, and in/out, and in 3 rotations: pitch, yaw, and roll. In fracture care, the principle of 6DOF can be applied to each individual fracture fragment to help better understand fracture reduction and alignment. In the instance of a distal radius fracture, the 6DOF concept can be utilized to reduce the articular block in a systematic and controlled fashion. The articular block may be displaced in 3 translations-shortened (proximal/distal axis), dorsally translated (volar/dorsal axis), and radially translated (radial/ulnar axis). The articular block may also be displaced in 3 rotations-dorsally tilted (rotated about the radial/ulnar axis or in the sagittal plane), decreased radial inclination (rotated about the volar/dorsal axis or in the coronal plane), and supinated (rotated about the proximal/distal axis or in the axial plane). We present a surgical technique of open reduction and internal fixation of a distal radius fracture through a volar approach where we address the distal segment's instability in 6DOF in a stepwise format.

Marked virulence and azole resistance in Candida albicans isolated from patients with periodontal disease.

Candida albicans is an opportunistic fungus frequently associated with periodontal diseases. The objective of this study was to determine the expression patterns of virulence genes associated with those of azole resistance among the strains of C. albicans isolated from patients with periodontal disease. We isolated 80 strains of C. albicans from patients with periodontal disease enrolled from two dental clinics and their antifungal susceptibilities were evaluated using the disc diffusion method. C. albicans and its virulence genes were identified using PCR. The expressions of the virulence genes of C. albicans were analyzed using real-time PCR post in vitro infection of the cell line A549. The phenotype for resistance against azoles such as ketoconazole and fluconazole was observed in all analyzed strains (n = 80), which coincided with the high frequency of occurrence of the genes CDR1 and MDR1 associated with resistance. The frequencies of detection and expression of the genes HWP1 (47/15), ALS1 (80/66), ALS3 (70/30), LIP1 (78/44), LIP4 (77/65), LIP5 (79/58), LIP6 (79/58), PLB1 (79/65), and PLB2 (80/66) were found to be higher in the strains of C. albicans isolated from patients with moderate periodontitis and different expression patterns associated with those for azole resistance were identified. It could be elucidated that the high expression of virulence markers associated with azole resistance in C. albicans might be contributing to the chronicity of periodontal infections.

Virulence gene transcription, phylogroups, and antibiotic resistance of cervico-vaginal pathogenic E. coli in Mexico.

The pathogenicity of Escherichia coli strains that cause cervico-vaginal infections (CVI) is due to the presence of several virulence genes. The objective of this study was to define the variability regarding the genotype of antibiotic resistance, the transcription profiles of virulence genes after in vitro infection of the vaginal cell line A431 and the phylogroup composition of a group of cervico-vaginal E. coli strains (CVEC). A total of 200 E. coli strains isolated from Mexican women with CVI from two medical units of the Mexican Institute of Social Security were analysed. E. coli strains and antibiotic resistance genes were identified using conventional polymerase chain reaction (PCR), and phylogroups were identified using multiplex PCR. Virulence gene transcription was measured through reverse-transcriptase real-time PCR after infection of the vaginal cell line A431. The most common antibiotic resistance genes among the CVEC strains were aac(3)II, TEM, dfrA1, sul1, and qnrA. The predominant phylogroup was B2. The genes most frequently transcribed in these strains were fimH, papC, irp2, iroN, kpsMTII, cnf1, and ompT, mainly in CVEC strains isolated from chronic and occasional vaginal infections. The strains showed a large diversity of transcription of the virulence genes phenotype and antibiotic resistance genotype, especially in the strains of phylogroups, B2, A, and D. The strains formed 2 large clusters, which contained several subclusters. The genetic diversity of CVEC strains was high. These strains have a large number of transcription patterns of virulence genes, and one-third of them carry three to seven antibiotic resistance genes.

Temporal and region-specific effects of sleep fragmentation on gut microbiota and intestinal morphology in Sprague Dawley rats.

Sleep is a fundamental biological process, that when repeatedly disrupted, can result in severe health consequences. Recent studies suggest that both sleep fragmentation (SF) and dysbiosis of the gut microbiome can lead to metabolic disorders, though the underlying mechanisms are largely unclear. To better understand the consequences of SF, we investigated the effects of acute (6 days) and chronic (6 weeks) SF on rats by examining taxonomic profiles of microbiota in the distal ileum, cecum and proximal colon, as well as assessing structural and functional integrity of the gastrointestinal barrier. We further assayed the impact of SF on a host function by evaluating inflammation and immune response. Both acute and chronic SF induced microbial dysbiosis, more dramatically in the distal ileum (compared to other two regions studied), as noted by significant perturbations in alpha- and beta-diversity; though, specific microbial populations were significantly altered throughout each of the three regions. Furthermore, chronic SF resulted in increased crypt depth in the distal ileum and an increase in the number of villi lining both the cecum and proximal colon. Additional changes were noted with chronic SF, including: decreased microbial adhesion and penetration in the distal ileum and cecum, elevation in serum levels of the cytokine KC/GRO, and depressed levels of corticotropin. Importantly, our data show that perturbations to microbial ecology and intestinal morphology intensify in response to prolonged SF and these changes are habitat specific. Together, these results reveal consequences to gut microbiota homeostasis and host response following acute and chronic SF in rats.

O-serogroups of multi-drug resistant cervicovaginal Escherichia coli harboring a battery of virulence genes.

Multi-drug resistant cervicovaginal Escherichia coli (CVEC) infections are a serious health problem. The aim of this study is to determine the patterns of virulence genes, antibiotic resistance and O-serogroups of CVEC isolated in Mexico. Two hundred strains of CVEC were isolated from women attending two Clinics at the Instituto Mexicano del Seguro Social. E. coli O-serogroups and virulence markers were identified by PCR. Antibiotic susceptibility was determined using the Kirby-Bauer disc-diffusion method. Serogroups O25 (50%), O75 (9%) and O15 (7.5%) were the most frequent among the CVEC strains isolated. The frequencies for antibiotic resistance were ampicillin 97%, (n = 194); carbenicillin 93.5%, (n = 187); cefalotin 77%, (n = 154); and nitrofurantoin 71%, (n = 142). The frequency of multiresistant isolates (3-12 drugs) was 197 (98.5%). The most frequent virulence genes found were feoB (91.5%), fimH (89.5%), kpsMT11 (75%), iutA (66%), and iroN (59%). One hundred and four distinct patterns of virulence markers with antibiotic-resistance genes associated with O-serogroups were identified amongst CVEC isolates. In conclusion: most CVEC strains isolated were multiresistant to antibiotics, belonged to three O-serogroups, and possessed a battery of virulence factors. This knowledge may lead to improved guidelines and standards for treating cervicovaginal infections.

Role of deubiquitinases in DNA damage response.

DNA damage response (DDR) serves as an integrated cellular network to detect cellular stress and react by activating pathways responsible for halting cell cycle progression, stimulating DNA damage repair, and initiating apoptosis. Efficient DDR protects cells from genomic instability while defective DDR can allow DNA lesions to go unrepaired, causing permanent mutations that will affect future generations of cells and possibly cause disease conditions such as cancer. Therefore, DDR mechanisms must be tightly regulated in order to ensure organismal health and viability. One major way of DDR regulation is ubiquitination, which has been long known to control DDR protein localization, activity, and stability. The reversal of this process, deubiquitination, has more recently come to the forefront of DDR research as an important new angle in ubiquitin-mediated regulation of DDR. As such, deubiquitinases have emerged as key factors in DDR. Importantly, deubiquitinases are attractive small-molecule drug targets due to their well-defined catalytic residues that provide a promising avenue for developing new cancer therapeutics. This review focuses on the emerging roles of deubiquitinases in various DNA repair pathways.

Anisotropic cellular forces support mechanical integrity of the Stratum Corneum barrier.

The protective function of biological surfaces that are exposed to the exterior of living organisms is the result of a complex arrangement and interaction of cellular components. This is the case for the most external cornified layer of skin, the stratum corneum (SC). This layer is made of corneocytes, the elementary 'flat bricks' that are held together through adhesive junctions. Despite the well-known protective role of the SC under high mechanical stresses and rapid cell turnover, the subtleties regarding the adhesion and mechanical interaction among the individual corneocytes are still poorly known. Here, we explore the adhesion of single corneocytes at different depths of the SC, by pulling them using glass microcantilevers, and measuring their detachment forces. We measured their interplanar adhesion between SC layers, and their peripheral adhesion among cells within a SC layer. Both adhesions increased considerably with depth. At the SC surface, with respect to adhesion, the corneocyte population exhibited a strong heterogeneity, where detachment forces differed by more than one order of magnitude for corneocytes located side by side. The measured detachment forces indicated that in the upper-middle layers of SC, the peripheral adhesion was stronger than the interplanar one. We conclude that the stronger peripheral adhesion of corneocytes in the SC favors an efficient barrier which would be able to resist strong stresses.

Multiple antibiotic resistances and virulence markers of uropathogenic Escherichia coli from Mexico.

Virulence and antibiotic resistance properties related to different Escherichia coli phylogenetic groups have not been studied in detail in Mexico. We aimed to identify patterns of virulence genes and multidrug resistance in phylogenetic groups of uropathogenic strains (UPEC). Strains of E. coli were isolated from outpatients with urinary tract infections (UTIs), who went to unit of the public health sector in the State of Mexico. E. coli virulence markers and phylogenetic groups were identified by PCR. Susceptibility to 12 antimicrobials was determined by Kirby-Bauer. E. coli was identified in 60.4% (n = 194) of the patients with UTIs. Phylogroups B2 51% (n = 99), A 13.4% (n = 26) and B1 10.3% (n = 20) were the most frequent. Resistance to three or up to eleven antibiotics was detected in most phylogroups (n = 188). The genes fimH (n = 146), feoB (n = 179), iutA (n = 178), sitA (n = 121), fyuA (n = 99), and traT (n = 142) were mainly detected in strains of phylogroups B2, A, B1, C, and D. Seventy-two patterns of virulence markers were distributed across eight E. coli phylogenetic groups. A high frequency of virulence markers and the multiple antibiotic resistance phenotypes was observed in the phylogroups. The genes of extended-spectrum ß-lactamases (ESBLs) found with higher frequency among UPEC strains were blaTEM, blaSHV y blaCTX-M group 1, CIT (plasmid-mediated AmpC ß-lactamase), and blaOXA-like. In conclusion, our findings show the importance of surveillance, permanent monitoring, and particularly controlled prescription of antibiotics by physicians in the social security health system to reduce the spread of highly virulent UPEC strains that are resistant to multiple antimicrobial agents.

Rearrangements under confinement lead to increased binding energy of Synaptotagmin-1 with anionic membranes in Mg2+ and Ca2.

Synaptotagmin-1 (Syt1) is the primary calcium sensor (Ca2+ ) that mediates neurotransmitter release at the synapse. The tandem C2 domains (C2A and C2B) of Syt1 exhibit functionally critical, Ca2+ -dependent interactions with the plasma membrane. With the surface forces apparatus, we directly measure the binding energy of membrane-anchored Syt1 to an anionic membrane and find that Syt1 binds with ~6 kB T in EGTA, ~10 kB T in Mg2+ and ~18 kB T in Ca2+ . Molecular rearrangements measured during confinement are more prevalent in Ca2+ and Mg2+ and suggest that Syt1 initially binds through C2B, then reorients the C2 domains into the preferred binding configuration. These results provide energetic and mechanistic details of the Syt1 Ca2+ -activation process in synaptic transmission.

Egg CD9 protein tides correlated with sperm oscillations tune the gamete fusion ability in mammal.

Mammalian fertilization involves membrane events-adhesion, fusion, sperm engulfment, membrane block to polyspermy-whose causes remain largely unknown. Recently, specific oscillations of the sperm in contact with the egg were shown to be necessary for fusion. Using a microfluidic chip to impose the venue for the encounter of two gametes allowed real-time observation of the membrane remodelling occurring at the sperm/egg interface. The spatiotemporal mapping of egg CD9 revealed that this protein concentrates at the egg/sperm interface as a result of sperm oscillations, until a CD9-rich platform is nucleated on which fusion immediately takes place. Within 2-5 min after fusion, most of the CD9 leaves the egg for the external aqueous medium. Then an egg membrane wave engulfs the sperm head in ~25 min. These results show that sperm oscillations initiate the CD9 recruitment that causes gamete fusion after which CD9 and associated proteins leave the membrane in a process likely to contribute to block polyspermy. They highlight that the gamete fusion story in mammals is an unexpected interplay between mechanical constraints and proteins.

Influence of shape and dispersion media of titanium dioxide nanostructures on microvessel network and ossification.

Titanium dioxide nanoparticles (TiO2 NPs) production has been used for pigment, food and cosmetic industry and more recently, shaped as belts for treatment of contaminated water, self-cleaning windows and biomedical applications. However, the toxicological data have demonstrated that TiO2 NPs inhalation induce inflammation in in vivo models and in vitro exposure leads to cytotoxicity and DNA damage. Dermal exposure has limited adverse effects and the possible risks for implants used for tissue regeneration is still under research. Then, it has been difficult to establish a straight statement about TiO2 NPs toxicity since route of exposure and shapes of nanoparticles play an important role in the effects. In this study we aimed to investigate the effect of three different types of TiO2 NPs (industrial, food-grade and belts) dispersed in fetal bovine serum (FBS) and saline solution (SS) on microvessel network, angiogenesis gene expression and femur ossification using a chick embryo model after an acute exposure of NPs on the day 7 after eggs fertilization. Microvascular density of chorioallantoic membrane (CAM) was analyzed after 7days of NPs injection and vehicles induced biological effects per se. NPs dispersed in FBS or SS have slight differences in microvascular density, mainly opposite effect on angiogenesis gene expression and no effects on femur ossification for NPs dispersed in SS. Interestingly, NPs shaped as belts dramatically prevented the alterations in ossification induced by FBS used as vehicle.

Structure stability of HKUST-1 towards water and ethanol and their effect on its CO2 capture properties.

Water and ethanol stabilities of the crystal structure of the Cu-based metal-organic framework (MOF) HKUST-1 have been investigated. Vapour (water and ethanol) sorption isotherms and cyclability were measured by a dynamic strategy. The ethanol sorption capacity of HKUST-1 at 303 K remained unchanged contrasting water sorption (which decreased along with the sorption experiment time). Considering the binding energy of each sorbate with the open Cu(ii) sites, obtained by the use of diffusion coefficients, we showed the superior crystal stability of the HKUST-1 framework towards ethanol. Finally, a small quantity of ethanol (pre-adsorbed) slightly enhanced CO2 capture without crystal structure degradation.

Virulence factors, antibiotic resistance phenotypes and O-serogroups of Escherichia coli strains isolated from community-acquired urinary tract infection patients in Mexico.

BACKGROUND/PURPOSE: Uropathogenic Escherichia coli (UPEC) strains isolated from patients with community-acquired urinary tract infections (UTIs) were assessed to determine the prevalence of virulence genes, antibiotic resistance, and the O-serogroup of the strains. METHODS: Consenting patients with community-acquired UTI were enrolled at Unidad Médica Familiar Number 64 (Instituto Mexicano del Seguro Social, Estado de Mexico, Mexico) and 321 urine samples were collected. Polymerase chain reaction (PCR) was used to assess 24 virulence genes and 14 O-serogroups. The Kirby-Bauer method was used to evaluate the antibiotic susceptibility of the isolated strains to 12 commonly used antibiotics. RESULTS: A total of 194 strains were identified as E. coli using standard biochemical tests, followed by PCR amplification of 16S ribosomal RNA gene. Only 58.2% of the strains belonged to the assessed 14 O-serogroups. The serogroups O25, O15, O8, and O75 were present in 20.6%, 17%, 6.1%, and 4.6% of strains, respectively. The most frequently occurring virulence genes among UPEC strains included kpsMT (92.2% strains), usp (87.1%), irp2 (79.3%), iha (64.9%), fim (61.3%), set (36%), astA (33.5%), pap (24.7%), and papGII (21.1%). In addition, 97% of the strains were multi-drug resistant (coresistance to 3-11 antibiotics). CONCLUSION: The isolated UPEC strains predominantly belonged to three serogroups (O25, O15, and O8), harboured numerous virulence genes, and are multiresistant to antibiotics. The findings of this study could be used to orient UTI treatment strategies and in epidemiological studies in Mexico.