Extended spectrum β-lactamase producing uropathogenic Escherichia coli and the correlation of biofilm with antibiotics resistance in Nepal

Occurrence of multidrug resistance associated with extended-spectrum β‑lactamase and the biofilm forming ability of Escherichia coli in environmental swine husbandry

Extended-spectrum beta-lactamase (ESBL) production and biofilm formation are mechanisms employed by Escherichia coli to resist beta-lactam antibiotics. Thus, we aimed to examine antibiotic resistance associated with ESBL production and biofilm formation in E. coli isolates from swine farms in Southern Thailand. In total, 159 E. coli isolates were obtained, with 44 isolates identified as ESBL producers, originating from feces (18.87 %) and wastewater (8.80 %) samples. All ESBL-producing strains exhibited resistance to ampicillin (100 %), followed by the cephalosporin group (97.73 %) and tetracycline (84.09 %). Multidrug resistance was observed in 17 isolates (38.63 %). Among the isolates from feces samples, the blaGES gene was the most prevalent, detected in 90 % of the samples, followed by blaCTX-M9 (86.67 %) and blaCTX-M1 (66.67 %), respectively. In the bacteria isolated from wastewater, both blaGES and blaCTX-M9 genes were the predominant resistance genes, detected in 100 % of the isolates, followed by blaCTX-M1 (64.29 %) and blaTEM (50 %), respectively. Strong biofilm formation was observed in 11 isolates (36.67 %) from feces and 4 isolates (25.57 %) from wastewater samples. Notably, nearly 100 % of ESBL-producing strains isolated from feces tested positive for both pgaA and pgaC genes, which play a role in intracellular adhesion and biofilm production. These findings contribute to the understanding and potential control of ESBL-producing E. coli, and the dissemination of antibiotic resistance and biofilm-related genes in swine farms.

Modified Zhibai Dihuang pill alleviated urinary tract infection induced by extended-spectrum β-lactamase Escherichia coli in rats by regulating biofilm formation

CONTEXT

Zhibai Dihuang pill (ZD), a traditional Chinese medicine nourishes Yin and reduces internal heat, is believed to have therapeutic effects on urinary tract infections (UTIs).

OBJECTIVE

To explore the effects and mechanism of modified ZD (MZD) on UTI induced by extended-spectrum β-lactamase (ESBLs) Escherichia coli.

MATERIALS AND METHODS

Thirty Sprague-Dawley rats were randomly divided into control, model (0.5 mL 1.5 × 108 CFU/mL ESBLs E. coli), MZD (20 g/kg MZD), LVFX (0.025 g/kg LVFX), and MZD + LVFX groups (20 g/kg MZD + 0.025 g/kg LVFX), n = 6. After 14 days of treatment, serum biochemical indicators, renal function indicators, bladder and renal histopathology, and urine bacterial counts in rats were determined. Additionally, the effects of MZD on ESBLs E. coli biofilm formation and related gene expression were analyzed.

RESULTS

MZD significantly decreased the count of white blood cells (from 13.12 to 9.13), the proportion of neutrophils (from 43.53 to 23.18), C-reactive protein (from 13.21 to 9.71), serum creatinine (from 35.78 to 30.15), and urea nitrogen (from 12.56 to 10.15), relieved the inflammation and fibrosis of bladder and kidney tissues, and reduced the number of bacteria in urine (from 2174 to 559). In addition, MZD inhibited the formation of ESBLs E. coli biofilms (2.04-fold) and decreased the gene expressions of luxS, pfS and ompA (1.41-1.62-fold).

DISCUSSION AND CONCLUSION

MZD treated ESBLs E. coli-induced UTI inhibited biofilm formation, providing a theoretical basis for the clinical application of MZD. Further study on the clinical effect of MZD may provide a novel therapy option for UTI.

Extended-spectrum β-lactamases producing Enterobacteriaceae (ESBL-PE) prevalence in Nepal: A systematic review and meta-analysis

An alarming increase in the occurrence of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) has threatened the treatment and management of bacterial infections. This systematic review and meta-analysis aimed to provide a quantitative estimate of the prevalence of ESBL among the members of the Enterobacteriaceae family by analyzing the community-based and clinical studies published between 2011 and 2021 from Nepal and determine if ESBL-PE correlates with multidrug resistance (MDR). The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed for systematic review and meta-analysis and the articles' quality was assessed using the Newcastle-Ottawa scale. Of the 2529 articles screened, 65 articles were systematically reviewed, data extracted, and included in in-depth meta-analysis. The overall pooled prevalence of ESBL-producers in Enterobacteriaceae was 29 % (95 % CI: 26-32 %) with high heterogeneity (I2 = 96 %, p < 0.001). Escherichia coli was the predominant ESBL-producing member of the Enterobacteriaceae family, followed by Citrobacter spp. and Klebsiella spp. The prevalence of ESBL-PE increased from 18.7 % in 2011 to 29.5 % in 2021. A strong positive correlation (r = 0.98) was observed between ESBL production and MDR in Enterobacteriaceae. ESBL-PE isolates showed high resistance to ampicillin, cephalosporins, and amoxicillin-clavulanic acid, and blaCTX-M type was the most reported gene variant among ESBL-PE. In conclusion, this study demonstrated an increased prevalence of ESBL-PE in Nepal over the last decade, and such isolates showed a high level of MDR against the β-lactams and non-β-lactam antibiotics. Tackling the rising antibiotic resistance (AR) and MDR in ESBL-PE would require concerted efforts from all stakeholders to institute effective infection control programs in the community and clinical settings.

Antimicrobial resistance and biofilm formation of Escherichia coli in a Vietnamese Pangasius fish processing facility

This study aimed to investigate the occurrence, antibiotic resistance, and biofilm formation of Escherichia coli in the Vietnamese Pangasius fish processing facility. Among 144 samples including Pangasius fish, wash water, food contact surfaces, and personnel gloves, 18 E. coli isolates was detected and characterized. The E. coli was detected most frequently in wash water samples (22%, 8/36), followed by Pangasius fish (18%, 8/45). According to the antibiotic susceptibility test by the disc diffusion method, isolates showed the highest resistance against sulfamethoxazole/trimethoprim (45%), followed by tetracycline (39%), whereas all the E. coli isolates were susceptible to meropenem and fosfomycin. Notably, 39% of the isolates (7/18) were found to be multidrug resistant while no E. coli isolates were confirmed as extended-spectrum β-lactamase producers by the double-disk synergy test. The potency to form biofilm on the polystyrene surface of E. coli isolates indicated that 44% of the isolates (8/18) were classified as weak, 39% (7/18) as moderate, and 17% (3/18) as strong biofilm formers. Interestingly, multidrug resistant E. coli isolates were observed in moderate and strong biofilm producers. Additionally, either slightly acidic hypochlorous water with 40 mg/L of available chlorine or sodium hypochlorite with 100 mg/L of available chlorine exhibited a significant reduction in biofilm mass and biofilm cells of E. coli isolates. This study may provide helpful information about the actual state of E. coli isolates for effective control in the fish processing plant.

Uropathogenic Escherichia coli (UPEC)-Associated Urinary Tract Infections: The Molecular Basis for Challenges to Effective Treatment

Urinary tract infections (UTIs) are among the most common bacterial infections, especially among women and older adults, leading to a significant global healthcare cost burden. Uropathogenic Escherichia coli (UPEC) are the most common cause and accounts for the majority of community-acquired UTIs. Infection by UPEC can cause discomfort, polyuria, and fever. More serious clinical consequences can result in urosepsis, kidney damage, and death. UPEC is a highly adaptive pathogen which presents significant treatment challenges rooted in a complex interplay of molecular factors that allow UPEC to evade host defences, persist within the urinary tract, and resist antibiotic therapy. This review discusses these factors, which include the key genes responsible for adhesion, toxin production, and iron acquisition. Additionally, it addresses antibiotic resistance mechanisms, including chromosomal gene mutations, antibiotic deactivating enzymes, drug efflux, and the role of mobile genetic elements in their dissemination. Furthermore, we provide a forward-looking analysis of emerging alternative therapies, such as phage therapy, nano-formulations, and interventions based on nanomaterials, as well as vaccines and strategies for immunomodulation. This review underscores the continued need for research into the molecular basis of pathogenesis and antimicrobial resistance in the treatment of UPEC, as well as the need for clinically guided treatment of UTIs, particularly in light of the rapid spread of multidrug resistance.

Correlation of biofilm formation, virulence factors, and phylogenetic groups among Escherichia coli strains causing urinary tract infection: A global systematic review and meta-analysis

Background

Different virulence factors are involved in the pathogenesis of urinary tract infection (UTI) caused by Uropathogenic Escherichia coli (UPEC); hence, this study aimed to study the prevalence of biofilm formation, virulence factors, and phylogenetic groups and their correlation with biofilm formation among UPEC isolates through a systematic review and meta-analysis.

Materials and Methods

A literature search was conducted from 1, 2000, to the end of 2021 in different databases for studies that reported biofilm together with virulence genes or phylogenetic groups in UPEC isolates from patients with UTI according to PRISMA protocol. Data were analyzed by Comprehensive meta-analysis software.

Results

The pooled prevalence of biofilm formers was 74.7%. The combined prevalence of phylogenetic Groups A, B1, B2, and D (s) were reported at 19.6%, 11%, 50.7%, and 20.5%, respectively. The most common virulence genes reported worldwide were fimA, ecpA, and fimH, with a combined prevalence of 90.3%, 86.6%, and 64.9%, respectively. The pooled prevalence of biofilm formation in UPEC isolates with phylogenetic Groups A, B1, B2, D, C, and F were 12.4%, 8.7%, 33.7%, 12.4%, 2.6%, and 2.65%, respectively. Several studies showed a correlation between biofilm production and virulence genes, or phylogenetic groups.

Conclusion

Regarding data obtained, the high level of combined biofilm formation (74.7%) and the presence of a positive correlation between biofilm production and virulence genes, or phylogenetic groups as reported by the most studies included in the present review, indicates an important role of biofilm in the persistence of UPEC in the UTI.

Effect of Essential Oil from Lippia origanoides on the Transcriptional Expression of Genes Related to Quorum Sensing, Biofilm Formation, and Virulence of Escherichia coli and Staphylococcus aureus

Microbial infections resistant to conventional antibiotics constitute one of the most important causes of mortality in the world. In some bacterial species, such as Escherichia coli and Staphylococcus aureus pathogens, biofilm formation can favor their antimicrobial resistance. These biofilm-forming bacteria produce a compact and protective matrix, allowing their adherence and colonization to different surfaces, and contributing to resistance, recurrence, and chronicity of the infections. Therefore, different therapeutic alternatives have been investigated to interrupt both cellular communication routes and biofilm formation. Among these, essential oils (EO) from Lippia origanoides thymol-carvacrol II chemotype (LOTC II) plants have demonstrated biological activity against different biofilm-forming pathogenic bacteria. In this work, we determined the effect of LOTC II EO on the expression of genes associated with quorum sensing (QS) communication, biofilm formation, and virulence of E. coli ATCC 25922 and S. aureus ATCC 29213. This EO was found to have high efficacy against biofilm formation, decreasing-by negative regulation-the expression of genes involved in motility (fimH), adherence and cellular aggregation (csgD), and exopolysaccharide production (pgaC) in E. coli. In addition, this effect was also determined in S. aureus where the L. origanoides EO diminished the expression of genes involved in QS communication (agrA), production of exopolysaccharides by PIA/PNG (icaA), synthesis of alpha hemolysin (hla), transcriptional regulators of the production of extracellular toxins (RNA III), QS and biofilm formation transcriptional regulators (sarA) and global regulators of biofilm formation (rbf and aur). Positive regulation was observed on the expression of genes encoding inhibitors of biofilm formation (e.g., sdiA and ariR). These findings suggest that LOTCII EO can affect biological pathways associated with QS communication, biofilm formation, and virulence of E. coli and S. aureus at subinhibitory concentrations and could be a promising candidate as a natural antibacterial alternative to conventional antibiotics.

Antimicrobial and antioxidant activity of phenolic extracts from walnut (Juglans regia L.) green husk by using pressure-driven membrane process

In this study, antioxidant (DPPH and metal chelating), DNA cleavage, biofilm, and antimicrobial properties of extracted phenol from the walnut green husk (WGH) and its different concentrate and permeate samples were evaluated. For maximum phenolic compound extraction from the WGH first, the effects of solvent type (deionized water, methanol, n-hexane, acetone, and ethanol), solvent temperature (25-75 °C), and extraction time (0.5-24 h) were optimized. Then to concentrate phenolic compounds a pressure-driven membrane process was used with four different membrane types. The phenol contents of the concentrate samples were found to be microfiltration (MF) concentrate 4400 mg/L, ultrafiltration (UF) concentrate 4175 mg/L, nanofiltration (NF) concentrate 8155 mg/L, and reverse osmosis (RO) concentrate 8100 mg/L. LC-MSMS was used to determine the quantification of phenolic compounds in permeate and concentrate streams. In addition, all of the concentrate samples with high phenol content showed a high antioxidant activity as 100% with MF concentrate, UF concentrate, NF concentrated and RO concentrated. Likewise, concentrate samples were found to have very high antibiofilm activity as 82.86% for NF concentrate againts S. aureus, 85.80% for NF concentrate against P. aureginosa, 80.95% for RO concentrate against S. aureus, and 83.61% for RO-concentrate against P. aureginosa. When the antimicrobial activity of the extracted phenol from WGH and its different concentrate and permeate samples were evaluated by micro dilution and disk diffusion methods, it was found that the ability of the concentrate samples to inhibit bacterial growth was much higher than permeate ones. In addition, extracted phenol from WGH and its different concentrate and permeate samples showed significant DNA nuclease activity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05588-w.

Antibiotic Resistance, Biofilm Formation and Sub-Inhibitory Hydrogen Peroxide Stimulation in Uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) is the most prevalent cause of urinary tract infections (UTIs). Biofilm formation and antibiotic resistance could be high among the causative agent. The purpose of this study was to determine antibiotic resistance, biofilm production, and biofilm-associated genes, bcsA and csgD, and sub-inhibitory hydrogen peroxide (H2O2) stimulation in UPEC for biofilm formation. A total of 71 UPEC were collected from a tertiary care hospital in Kathmandu and subjected to identify antibiotic susceptibility using Kirby-Bauer disk diffusion. The biofilm formation was assessed using microtiter culture plate method while pellicle formation was tested by a tube method. In representative 15 isolates based on biofilm-forming ability, bcsA and csgD were screened by conventional polymerase chain reaction, and treated with sub-lethal H2O2. The UPEC were found the most susceptible to meropenem (90.2%), and the least to ampicillin (11.3%) in vitro and 90.1% of them were multi-drug resistant (MDR). Most UPEC harbored biofilm-producing ability (97.2%), and could form pellicle at 37°C. Among representative 15 isolates, csgD was detected only among 10 isolates (66.67%) while bcsA gene was present in 13 isolates (86.67%). This study revealed that level of biofilm production elevated after sub-lethal H2O2 treatment (P = .041). These findings suggested that the pathogens are emerging as MDR. The biofilm production is high and the majority of selected strains contained bcsA and csgD genes. Pellicle formation test was suggestive to be an alternative qualitative method to screen biofilm production in UPEC. The sub-inhibitory concentration of H2O2 may contribute in increasing biofilm formation in UPEC.

Antibiofilm Activity of Sundew Species against Multidrug-Resistant Escherichia coli Strains

Species of the genus Drosera, known for carnivorous plants, such as sundew, have been traditionally used for centuries as medicinal plants. Efficacy-determining compounds are naphthoquinones and flavonoids. Flavonoids possess a broad spectrum of bioactive properties, including biofilm inhibitory activity. Biofilms render antibiotics ineffective, contributing to the current rise in antimicrobial resistance. In this study, the biofilm inhibitory activity of two European sundew species (Drosera rotundifolia and Drosera intermedia) grown agriculturally in Germany and four commercial sundew products (declared as Drosera longifolia, Drosera sp. and Drosera planta trit.) against three multidrug-resistant Escherichia coli strains was tested. The aim of the study was to comparatively investigate the biofilm inhibitory potential of sundew species extracts grown locally in northern Germany and commercial sundew products. The minimum biofilm inhibitory concentration of the European sundew species was approx. 35 µg mL^-1. In comparison, commercial sundew products ranged in concentration from 75 to 140 µg mL^-1. Additionally, individual compounds isolated from European sundew were tested. Among these compounds, biofilm inhibitory activity was determined for four of the eight substances, with 2″-O-galloyl hyperoside standing out for its activity (38 µg mL^-1). The whole plant extracts of Drosera rotundifolia and Drosera intermedia proved to be more effective than the commercial products and the single compounds in its biofilm inhibition activity against Escherichia coli strains. Sundew extracts may serve as a potential therapeutic approach for targeting biofilm production.

Phylogenetic groups, serogroups and virulence factors of uropathogenic Escherichia coli isolated from patients with urinary tract infection in Baghdad, Iraq

Background and Objectives

Uropathogenic Escherichia coli (UPEC) is divided into different phylogenetic groups that differ in their antibiotic resistance patterns, serogroups and pathogenicity. This study aimed to investigate the prevalence of phylogenetic groups of UPEC isolates and their relationship with serogroups and virulence factors in patients with UTIs.

Materials and Methods

Of the 412 urine samples tested a total of 150 UPEC were isolated and confirmed with PCR using 16S rRNA gene. Antibiotic resistance of the isolates was tested using disk diffusion method and the isolates were divided into phylogenetic groups by the quadruplex PCR method. The prevalence of serogroups and virulence genes were investigated using multiplex PCR.

Results

87 (58%) of the isolates belonged to phylogroup B2. Virulence genes fimH (95.3%), aer (49.3%) and serogroups O8 (22.3%), O25 (21.5%) showed the highest prevalence. The lowest drug resistance was observed against imipenem (4.6%) and meropenem (3.3%). The prevalence of multidrug-resistant and extended-spectrum beta-lactamases isolates were 60% and 61.3%, respectively. We also found a significant relationship between phylogenetic groups, serogroups and virulence factors among our isolates.

Conclusion

The high abundance of phylogenetic group B2, serogroups O8 and O25, and virulence genes fimH and aer indicate their importance in the pathogenesis of UPEC in this country.

Prevalencia de aislamientos de Escherichia coli y Klebsiella pneumoniae productoras de betalactamasas de espectro extendido en pacientes cubanos ambulatorios con infección del tracto urinario

Introducción. Las infecciones del tracto urinario (UTI) adquiridas en la comunidad causadas por enterobacterias productoras de β-lactamasas de espectro extendido (BLEE) son un fenómeno creciente a nivel mundial. Objetivo. Determinar la prevalencia de aislamientos de Escherichia coli y Klebsiella pneumoniae productoras de BLEE obtenidos de muestras de orina de pacientes ambulatorios con ITU adquirida en la comunidad, así como los perfiles de resistencia a antibióticos asociados al fenotipo BLEE. Materiales y métodos. Estudio descriptivo retrospectivo. Se analizaron 304 aislamientos de E. coli y 34 de K. pneumoniae obtenidos de urocultivos de pacientes con ITU adquirida en la comunidad atendidos entre enero 1 de 2019 y diciembre 31 de 2020 en el Hospital Clínico-Quirúrgico Docente Aleida Fernández Chardiet, provincia Mayabeque, Cuba. Se realizó un análisis bivariado (prueba x2) para determinar diferencias en las tasas de resistencia antibiótica entre las bacterias productoras de BLEE y las no productoras. Resultados. El 16.77% (51/304) y el 17.64 % (6/34) de los aislamientos de E. coli y K. pneumoniae se clasificaron como bacterias productoras de BLEE. En el caso de los aislados de E. coli productoras de BLEE, BLEE+ciprofloxacina fue el patrón de resistencia más frecuente (22/51; 43.13%), seguido por BLEE+ciprofloxacino y amikacina (14/51; 27.45%). Además, 41.17% (21/51); fueron multirresistentes. En el caso de K. pneumoniae productoras de BLEE, predominó el patrón de resistencia BLEE + ciprofloxacino, amikacina y nitrofurantoina (2/6; 33.33%), y 50 % (3/6) fueron multirresistentes. Conclusiones. Los resultados confirman la presencia de E. coli y K. pneumoniae productoras de BLEE, con una alta prevalencia de multirresistencia en pacientes con ITU adquirida en la comunidad en el municipio de Güines, Cuba.

Probiotic potentials of the silkworm gut symbiont Enterococcus casseliflavus ECB140, a promising L-tryptophan producer living inside the host

AIMS

L-tryptophan is an essential aromatic amino acid for the growth and development of animals. Studies about enteric L-tryptophan-producing bacteria are scarce. In this report, we characterized the probiotic potential of Enterococcus casseliflavus ECB140, focusing on its L-tryptophan production abilities.

METHODS AND RESULTS

ECB140 strain was isolated from the silkworm gut and can survive under strong alkaline environmental conditions. Bacterial colonization traits (motility and biofilm) were examined and showed that only ECB140 produced flagellum and strong biofilms compared with other Enterococcus strains. Comparative genome sequence analyses showed that only ECB140 possessed a complete route for L-tryptophan synthesis among all 15 strains. High-performance liquid chromatography and qRT-PCR confirmed the capability of ECB140 to produce L-tryptophan. Besides, the genome also contains the biosynthesis pathways of several other essential amino acids, such as phenylalanine, threonine, valine, leucine, isoleucine and lysine. These results indicate that ECB140 has the ability to survive passage through the gut and could act as a candidate probiotic.

CONCLUSIONS

The study describes a novel, natural silkworm gut symbiont capable of producing L-tryptophan. Enterococcus casseliflavus ECB140 physical and genomic attributes offer possibilities for its colonization and provide L-tryptophan for lepidopteran insects.

CTX-M-producing Escherichia coli strains: resistance to temocillin, fosfomycin, nitrofurantoin and biofilm formation

Aim: ESBL-producing and bacterial biofilms-forming Escherichia coli are associated with antimicrobial treatment failure. This study aimed to investigate the phenotypic resistance mechanisms of CTX-M E. coli against old antibiotics - cell wall synthesis inhibitors temocillin, nitrofurantoin and fosfomycin. Materials & Methods: Susceptibility to old antibiotics testing was performed using disk diffusion method, biofilm formation was evaluated spectrophotometrically, and PCR was used for the determination of CTX-M type. Results & conclusion: Temocillin was active against nearly 93%, nitrofurantoin and fosfomycin, respectively, 91.7% and 98.6% of tested E. coli. Thus, it demonstrated to be a good alternative therapeutic option against ESBL infections. Bacteria resistant to old antibiotics had CTX-M-15 or CTX-M-15, TEM-1 and OXA-1 combinations. No significant association was found between CTX-M E. coli resistance to temocillin, nitrofurantoin and fosfomycin; however, the level of biofilm formation was found as not affected by the type of CTX-M β-lactamases.

Correlation Between Antimicrobial Resistance, Virulence Determinants and Biofilm Formation Ability Among Extraintestinal Pathogenic Escherichia coli Strains Isolated in Catalonia, Spain

Escherichia coli is a well-characterized bacterium highly prevalent in the human intestinal tract and the cause of many important infections. The aim of this study was to characterize 376 extraintestinal pathogenic E. coli strains collected from four hospitals in Catalonia (Spain) between 2016 and 2017 in terms of antimicrobial resistance, siderophore production, phylogroup classification, and the presence of selected virulence and antimicrobial resistance genes. In addition, the association between these characteristics and the ability to form biofilms was also analyzed. The strains studied were classified into four groups according to their biofilm formation ability: non-biofilm formers (15.7%), weak (23.1%), moderate (35.6%), and strong biofilm formers (25.6%). The strains were highly resistant to ciprofloxacin (48.7%), trimethoprim-sulfamethoxazole (47.9%), and ampicillin (38%), showing a correlation between higher resistance to ciprofloxacin and lower biofilm production. Seventy-three strains (19.4%) were ESBL-producers. However, no relationship between the presence of ESBL and biofilm formation was found. The virulence factor genes fimH (92%), pgaA (84.6%), and irp1 (77.1%) were the most prevalent in all the studied strains. A statistically significant correlation was found between biofilm formation and the presence of iroN, papA, fimH, sfa, cnf, hlyA, iutA, and colibactin-encoding genes clbA, clbB, clbN, and clbQ. Interestingly, a high prevalence of colibactin-encoding genes (19.9%) was observed. Colibactin is a virulence factor, which interferes with the eukaryotic cell cycle and has been associated with colorectal cancer in humans. Most colibactin-encoding E. coli isolates belonged to phylogroup B2, exhibited low antimicrobial resistance but moderate or high biofilm-forming ability, and were significantly associated with most of the virulence factor genes tested. Additionally, the analysis of their clonal relatedness by PFGE showed 48 different clusters, indicating a high clonal diversity among the colibactin-positive strains. Several studies have correlated the pathogenicity of E. coli and the presence of virulence factor genes; however, colibactin and its relationship to biofilm formation have been scarcely investigated. The increasing prevalence of colibactin in E. coli and other Enterobacteriaceae and the recently described correlation with biofilm formation, makes colibactin a promising therapeutic target to prevent biofilm formation and its associated adverse effects.

A global systematic review and meta-analysis on correlation between Biofilm producers and Non-biofilm producers with antibiotic resistance in Uropathogenic Escherichiacoli

Escherichia coli accounts for nearly 80% of community-acquired and 50% of hospital-acquired urinary tract infections (UTI). This study aimed to evaluate the correlation between biofilm producers and Non-biofilm producers with antibiotic resistance in Uropathogenic Escherichia coli (UPEC) isolated from patients with UTI globally. The search was conducted between 1st 2000 to 30^th October 2021 in various databases (PubMed, Scopus, Web of sciences, and Google Scholar) with suitable MeSH terms, and text words. Then, after applying the appropriate inclusion and exclusion criteria on the studies for their selection, the data were analyzed by CMA software. Thirty-seven studies met the eligibility criteria to include. The pooled prevalence of ESBL and MDR isolates were reported 37.9%, and 65.8%, respectively. Biofilm formation varied between 13.3% and 99% all over the world. A total of 74.4% of all isolates were biofilm producers, out of which 28.6%, 35.2%, and 38.6% showed strong, moderate, and weak biofilm. The highest and lowest resistance was against Amoxicillin and Meropenem with the prevalence of 80.8%, and 13%, respectively. Fourteen out of 17(82.35%) studies reported a positive correlation between biofilm and antibiotic resistance. Findings showed high numbers of isolates were able to form biofilm, which is one of the factors of antibiotic resistance, and this has been confirmed by the positive significant correlation between biofilm formation and antibiotic resistance that has been reported by studies included. Therefore, due to the importance of biofilm in the etiology of UTI caused by UPEC, it should be prevented; consequently, bacterial resistance can be reduced and controlled.

Antibacterial and antibiofilm activity of Lagotis brachystachya extract against extended-spectrum β-lactamases-producing Escherichia coli from broiler chickens

Lagotis brachystachya Maxim (L. brachystachya) is an herb widely used in traditional Tibetan medicine. In the present study, the antibacterial activity of L. brachystachya extract to extended-spectrum-lactamases (ESBLs)-producing E. coli was determined by Kirby-Bauer disc diffusion, minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) methods as well as time-kill curve assay. Meanwhile, the biofilm inhibition and eradication effects of L. brachystachya extract on the ESBLs-producing E. coli were evaluated by crystal violet staining, and further confirmed by confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM). The results indicated that L. brachystachya extract exhibited moderate antibacterial activity, with diameter of inhibition zones varying from 15.4 to 20.3 mm, and the MIC and MBC values were 6.25 to 25 mg/mL and 12.5 to 100 mg/mL, respectively. Time-kill curve showed that 4 × MIC level of L. brachystachya extract concentration of was able to kill 99.9% of ESBLs-producing E. coli after 16 h treatment. The biofilm inhibition rate and eradication rate for the ESBLs-producing E. coli were 35.66 to 79.91% and 22.18 to 56.21% at MIC level of extract concentration, respectively. CLSM images showed that the biofilm became thinner as the ESBLs-producing E. coli isolate exposed to L. brachystachya extract with a concentration-dependent manner from 1/4 × MIC to MIC compared with the control isolate. SEM images indicated that L. brachystachya extract at 1/2 × MIC and MIC levels could evidently inhibit the biofilm formation or eradicate the mature biofilms. The effect of L. brachystachya highlights its potential of antibacterial and antibiofilm activities against the ESBLs-producing E. coli.

High Prevalence of Multidrug Resistance and Biofilm-Formation Ability Among Avian Escherichia coli Isolated from Broilers in Iran

The present study was conducted to determine the antimicrobial resistance pattern and biofilm-formation ability in 100 Avian-Pathogenic Escherichia coli (APEC) isolated from colibacillosis-suspected broilers and 100 Avian Fecal E. coli (AFEC) isolates from healthy broilers in Hamedan, Iran. All isolates were screened by polymerase chain reaction for antimicrobial resistance genes, class 1 and 2 integrons, and biofilm-associated genes. Besides, we assessed the possible relationship between biofilm-formation ability antibiotic resistance patterns, genetic background, and the pathogenicity of APEC strains. 81% of APEC and 73% of AFEC isolates showed multidrug resistance (MDR) phenotype; in addition, 45% of the APEC and 21% of the AFEC strains showed biofilm-formation ability. This is the first report of the biofilm formation ability in E. coli isolated from broilers in Iran. The most prevalent antibiotic resistance gene in APEC strains was tetA (68%), followed by sul1 (63%), dfrA1-like (51%), and bla_TEM (30%), whereas in AFEC strains, the frequencies of the antibiotic resistance genes were tetA (63%), sul1 (58%), dfrA1-like (49%), and bla_TEM (22%). Out of 81 MDR APEC isolates, 53 (65.4%) and 38 (46.91%) isolates were positive for intI1 and intI2 genes, respectively. In the AFEC strains intI1 and intI2 genes were presented in 57 and 33 isolates, respectively. All APEC isolates belonging to phylogenetic groups B1, B2, and C were MDR. The results of the present study indicate that isolates with biofilm-forming ability show more MDR properties and probably have more pathogenicity to broilers.

Combining Colistin with Furanone C-30 Rescues Colistin Resistance of Gram-Negative Bacteria in Vitro and in Vivo

The spread of multidrug-resistant (MDR) Gram-negative bacteria (GNB) has led to serious public health problems worldwide. Colistin, as a “last resort” for the treatment of MDR bacterial infections, has been used significantly in recent years and has led to the continuous emergence of colistin-resistant strains. In this study, we aimed to investigate the synergistic effect on the antimicrobial and antibiofilm activities of a colistin/furanone C-30 combination against colistin-resistant GNB in vitro and in vivo. According to antimicrobial resistance profiles, most of the colistin-resistant strains we collected showed MDR phenotypes. The checkerboard method and time-kill curve showed that the combination with furanone C-30 increases the antibacterial activity of colistin significantly. In addition, the furanone C-30/colistin combination can not only inhibit the formation of bacterial biofilm but also has a better eradication effect on preformed mature biofilms. The result of scanning electron microscopy (SEM) demonstrated that the furanone C-30/colistin combination led to a significant reduction in the number of cells in biofilms. Furthermore, furanone C-30 at 50 μg/ml did not cause any additional toxicity to RAW264.7 cells according to a cytotoxicity assay. In in vivo infection experiments, the furanone C-30/colistin combination increased the survival rate of infected Galleria mellonella larvae as well as decreased the microbial load in a mouse thigh infection model. The synergistic effect of the furanone C-30/colistin combination against colistin-resistant GNB is encouraging, and this work may shed light on a new therapeutic approach to combat colistin-resistant pathogens.

IMPORTANCE Colistin is among the few antibiotics effective against multidrug-resistant Gram-negative bacteria (GNB) clinical isolates. However, colistin-resistant GNB strains have emerged in recent years. Therefore, the combination of colistin and nonantibacterial drugs has attracted much attention. In this study, the furanone C-30/colistin combination showed good antibacterial and antibiofilm activity in vitro and in vivo. In addition, increased membrane permeability leads to the synergistic effect of the furanone C-30/colistin combination. Because of the low cytotoxicity of furanone C-30, this combination has good application prospects in clinical anti-infective therapy. This finding might shed light on the discovery of combination therapy for infections caused by colistin-resistant GNB pathogens.

Prevalence and Impact of Biofilms on Bloodstream and Urinary Tract Infections: A Systematic Review and Meta-Analysis

This study sought to assess the prevalence and impact of biofilms on two commonly biofilm-related infections, bloodstream and urinary tract infections (BSI and UTI). Separated systematic reviews and meta-analyses of observational studies were carried out in PubMed and Web of Sciences databases from January 2005 to May 2020, following PRISMA protocols. Studies were selected according to specific and defined inclusion/exclusion criteria. The obtained outcomes were grouped into biofilm production (BFP) prevalence, BFP in resistant vs. susceptible strains, persistent vs. non-persistent BSI, survivor vs. non-survivor patients with BSI, and catheter-associated UTI (CAUTI) vs. non-CAUTI. Single-arm and two-arm analyses were conducted for data analysis. In vitro BFP in BSI was highly related to resistant strains (odds ratio-OR: 2.68; 95% confidence intervals-CI: 1.60–4.47; p < 0.01), especially for methicillin-resistant Staphylococci. BFP was also highly linked to BSI persistence (OR: 2.65; 95% CI: 1.28–5.48; p < 0.01) and even to mortality (OR: 2.05; 95% CI: 1.53–2.74; p < 0.01). Candida spp. was the microorganism group where the highest associations were observed. Biofilms seem to impact Candida BSI independently from clinical differences, including treatment interventions. Regarding UTI, multi-drug resistant and extended-spectrum β-lactamase-producing strains of Escherichia coli, were linked to a great BFP prevalence (OR: 2.92; 95% CI: 1.30–6.54; p < 0.01 and OR: 2.80; 95% CI: 1.33–5.86; p < 0.01). More in vitro BFP was shown in CAUTI compared to non-CAUTI, but with less statistical confidence (OR: 2.61; 95% CI: 0.67–10.17; p < 0.17). This study highlights that biofilms must be recognized as a BSI and UTI resistance factor as well as a BSI virulence factor.

Mechanisms of Resistance in Gram-Negative Urinary Pathogens: From Country-Specific Molecular Insights to Global Clinical Relevance

Urinary tract infections (UTIs) are the most frequent hospital infections and among the most commonly observed community acquired infections. Alongside their clinical importance, they are notorious because the pathogens that cause them are prone to acquiring various resistance determinants, including extended-spectrum beta-lactamases (ESBL); plasmid-encoded AmpC β-lactamases (p-AmpC); carbapenemases belonging to class A, B, and D; qnr genes encoding reduced susceptibility to fluoroquinolones; as well as genes encoding enzymes that hydrolyse aminoglycosides. In Escherichia coli and Klebsiella pneumoniae, the dominant resistance mechanisms are ESBLs belonging to the CTX-M, TEM, and SHV families; p-AmpC; and (more recently) carbapenemases belonging to classes A, B, and D. Urinary Pseudomonas aeruginosa isolates harbour metallo-beta-lactamases (MBLs) and ESBLs belonging to PER and GES families, while carbapenemases of class D are found in urinary Acinetobacter baumannii isolates. The identification of resistance mechanisms in routine diagnostic practice is primarily based on phenotypic tests for the detection of beta-lactamases, such as the double-disk synergy test or Hodge test, while polymerase chain reaction (PCR) for the detection of resistance genes is mostly pursued in reference laboratories for research purposes. As the emergence of drug-resistant bacterial strains poses serious challenges in the management of UTIs, this review aimed to appraise mechanisms of resistance in relevant Gram-negative urinary pathogens, to provide a detailed map of resistance determinants in Croatia and the world, and to discuss the implications of these resistance traits on diagnostic approaches. We summarized a sundry of different resistance mechanisms among urinary isolates and showed how their prevalence highly depends on the local epidemiological context, highlighting the need for tailored interventions in the field of antimicrobial stewardship.

Phytochemical analysis of medicinal plants of Nepal and their antibacterial and antibiofilm activities against uropathogenic Escherichia coli

BACKGROUND

A biofilm is an extracellular polymeric substance (EPS) composed of polysaccharides, proteins, nucleic acids, and lipids that impede antibiotics and immune cells, thus providing a shielded environment for bacterial growth. Due to biofilm formation, some microbes can show up to 1000 fold increased resistance towards the antibiotics than the normal planktonic forms. The study was conducted to screen the crude extracts of medicinal plants used in Nepal for their in vitro antibiofilm activities.

METHODS

Total phenolic and total flavonoid contents were determined by using a Folin-Ciocalteau reagent and aluminium trichloride method, respectively. Resazurin assay was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The initial antibiofilm activities and their inhibitory concentration (IC₅₀) values were determined by the microtiter based modified crystal violet staining method.

RESULTS

Out of 25 different plant extracts were used for the study, methanolic extracts of 20 plants showed a biofilm inhibition activity against five different strong biofilm producing Escherichia coli strains. Calotropis gigantea exhibited inhibition against all five different E. coli strains with IC₅₀ values ranging from 299.7 ± 20.5 to 427.4 ± 2.7 μg/mL. Apart from that, Eclipta prostrata also showed biofilm formation inhibition, followed by Eupatorium adenophorum, Moringa oleifera, Ocimum tenuifolium, Oxalis lantifolia, Prunus persica, and Urtica parviflora. The extracts of C. gigantea, E. prostrata, Mangifera indica, O. tenuifolium, P. persica, and U. parviflora exhibited a moderate to poor MIC value ranging from 625 to 2500 μg/mL. The highest amount of phenolic content (TPC) was found in Acacia catechu followed by Morus alba, which was 38.9 and 25.1 mg gallic acid equivalents, respectively. The highest amount of flavonoid content was found in A. catechu followed by M. indica, which was 27.1 and 20.8 mg quercetin equivalents, respectively.

CONCLUSION

Extracts of C. gigantea, E. prostrata, P. persica, U. parviflora, and O. tenuifolium showed antibacterial as well as antibiofilm activity against pathogenic and strong biofilm producing E. coli. Thus, extracts or the pure compound from these medicinal plants could be used as antibiotics in the future.

Contribution of biofilm formation genetic locus, pgaABCD, to antibiotic resistance development in gut microbiome

The human gut microbiome is the presumed site in which the emergence and evolution of antibiotic-resistant organisms constantly take place. To delineate the genetic basis of resistance formation in gut microbiome strains, we investigated the changes in the subpopulation structure of Escherichia coli in rat intestine before and after antimicrobial treatment. We observed that antibiotic treatment was selected for an originally minor subpopulation E. coli carrying the biofilm-forming genetic locus pgaABCD and the toxin-antitoxin system HipAB. Such strains possessed dramatically enhanced ability to withstand the detrimental effects of antibiotics, becoming a dominant subspecies upon antibiotic treatment and eventually evolving into resistant mutants. In contrast, E. coli strains that did not carry pgaABCD and HipAB were eradicated upon antibiotic treatment. Our findings, therefore, suggested that genes encoding biofilm-forming ability played an important role in conferring specific gut E. coli strains the ability to evolve into resistant strains upon a prolonged antibiotic treatment, and that such strains may therefore be considered bacterial antibiotic resistance progenitor cells in the gut microbiome.

Molecular Identification and Antimicrobial Potential of Streptomyces Species from Nepalese Soil

Streptomyces are widely used for the production of secondary metabolites with diverse biological activities, including antibiotics. The necessity of alternative antimicrobial agents against multidrug-resistant pathogens is indispensable. However, the production of new therapeutics is delayed in recent days. Thus, the isolation of new Streptomyces species has drawn attention. Nepal-a country rich in biodiversity-has got high possibilities for the discovery of members of actinomycetes, especially in the higher altitudes. However, in vain, only a few screening research works have been reported from Nepal to date. Streptomyces species were isolated on ISP4 media, and characterization was performed according to morphological similarity and 16S rRNA sequence similarity using bioinformatic tools. Ethyl acetate extracts of Streptomyces species were prepared, and the antimicrobial activity was carried out using agar well diffusion technique. In this report, 18 Streptomyces species isolated from the soil were reported based on sequence analysis of 16S rRNA. Among them, 12 isolates have shown antibacterial activity against extended-spectrum beta-lactamase- (ESBL-) producing Escherichia coli. Here, we have also analyzed 16S rRNA in 27 Streptomyces species whose whole-genome sequence is available, which has revealed that some species have multiple copies of the 16S gene (∼1.5 kb) with significant variation in nucleotides. In contrast, some Streptomyces species shared identical DNA sequences in multiple copies of 16S rRNA. The sequencing of numerous copies of 16S rRNA is not necessary, and the molecular sequencing of this region is not sufficient for the identification of bacterial species. The Streptomyces species-derived ethyl acetate extracts from Nepalese soil demonstrate potential activity against ESBL-producing E. coli. Thus, they are potential candidates for antibiotics manufacturing in the future.