Pathogenic Enterobacteriaceae Research Articles

Comparative genomic identification and characterization of npcRNA homologs in Proteus vulgaris

Proteus vulgaris is a rod-shaped Gram-negative bacterium known to be the member of Enterobacteriaceae that is able to cause disease in human being. Generally, non-protein-coding RNAs (npcRNAs) do not code for proteins, but they play a vital role in gene regulation at the RNA level including pathogenicity. The present study aims at elucidating homologous npcRNAs from other bacteria in Proteus vulgaris. A comparative genomic analysis was carried out to identify npcRNA homolog of other Enterobacteriaceae pathogens in Proteus vulgaris. A total of 231 npcRNAs previously reported in Salmonella typhi, Salmonella typhimurium and Escherichia coli were screened using BLASTn tool against Proteus vulgaris genome. Interestingly, 33 npcRNAs are homologs to Proteus vulgaris. Northern blot analysis of 6 out of 33 npcRNA candidates confirmed their expression and showed that most of them are differentially expressed during lag, exponential and stationary growth phases. This study is the first approach of identification and characterization of npcRNAs in P. vulgaris. Hence, this could be a pioneer study to further validate the regulatory functions of these npcRNAs to fill the gaps in understanding of the pathogenicity of P. vulgaris.

Dietary calcium phosphate strongly impacts gut microbiome changes elicited by inulin and galacto-oligosaccharides consumption

BackgroundFructo-oligosaccharides (FOS), inulin, and galacto-oligosaccharides (GOS) are widely recognized prebiotics that profoundly affect the intestinal microbiota, including stimulation of bifidobacteria and lactobacilli, and are reported to elicit several health benefits. The combination of dietary FOS and inulin with calcium phosphate was reported to stimulate commensal Lactobacillus populations and protect the host against pathogenic Enterobacteriaceae, but little is known about the effects of GOS in diets with a different level of calcium phosphate.MethodsWe investigated the microbiome changes elicited by dietary supplementation with GOS or inulin using diets with high (100 mmol/kg) and low (30 mmol/kg) calcium phosphate levels in adult Wistar rats. Rats were acclimatized to the respective experimental diets for 14 days, after which fecal material was collected, DNA was extracted from fecal material, and the V3‑V4 region of the bacterial 16S rRNA gene was amplified with PCR, followed by microbial composition analysis. In tandem, the organic acid profiles of the fecal material were analyzed.ResultsFeeding rats non-supplemented (no prebiotic-added) diets revealed that diets rich in calcium phosphate favored members of the Firmicutes and increased fecal lactic, succinic, acetic, propionic, and butyric acid levels. In contrast, relatively low dietary calcium phosphate levels promoted the abundance of mucin degrading genera like Akkermansia and Bacteroides, and resulted in increased fecal propionic acid levels and modest increases in lactic and butyric acid levels. Irrespective of the calcium phosphate levels, supplementation with GOS or inulin strongly stimulated Bifidobacterium, while only high calcium phosphate diets increased the endogenous Faecalibaculum populations.ConclusionsDespite the prebiotic’s substantial difference in chemical structure, sugar composition, oligomer size, and the microbial degradation pathway involved in their utilization, inulin and GOS modulated the gut microbiota very similarly, in a manner that strongly depended on the dietary calcium phosphate level. Therefore, our study implies that the collection of detailed diet information including micronutrient balance is necessary to correctly assess diet-driven microbiota analysis.8vuNLHgRQosTp1CET2ayTDVideo

A pathogen-specific sRNA influences enterohemorrhagic Escherichia coli fitness and virulence in part by direct interaction with the transcript encoding the ethanolamine utilization regulatory factor EutR.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 relies on sRNAs to coordinate expression of metabolic and virulence factors to colonize the host. Here, we focus on the sRNA, named MavR (metabolism and virulence regulator), that is conserved among pathogenic Enterobacteriaceae. MavR is constitutively expressed under in vitro conditions that promote EHEC virulence gene expression. Using MS2-affinity purification coupled with RNA sequencing, the eutR transcript was identified as a putative target of MavR. EutR is a transcription factor that promotes expression of genes required for ethanolamine metabolism as well as virulence factors important for host colonization. MavR binds to the eutR coding sequence to protect the eutR transcript from RNase E-mediated degradation. Ultimately, MavR promotes EutR expression and in turn ethanolamine utilization and ethanolamine-dependent growth. RNAseq analyses revealed that MavR also affected expression of genes important for other metabolic pathways, motility, oxidative stress and attaching and effacing lesion formation, which contribute to EHEC colonization of the gastrointestinal tract. In support of the idea that MavR-dependent gene expression affects fitness during infection, deletion of mavR resulted in significant (∼10- to 100-fold) attenuation in colonization of the mammalian intestine. Altogether, these studies reveal an important, extensive, and robust phenotype for a bacterial sRNA in host-pathogen interactions.

Positive Synergistic Effects of Quercetin and Rice Bran on Human Gut Microbiota Reduces Enterobacteriaceae Family Abundance and Elevates Propionate in a Bioreactor Model.

Dietary fiber and flavonoids have substantial influence on the human gut microbiota composition that significantly impact health. Recent studies with dietary supplements such as quercetin and rice bran have shown beneficial impacts on the host alongside a positive influence of the gut microbiota. The specific bacterial species impacted by quercetin or rice bran in the diet is not well understood. In this study, we used a minibioreactor array system as a model to determine the effect of quercetin and rice bran individually, as well as in combination, on gut microbiota without the confounding host factors. We found that rice bran exerts higher shift in gut microbiome composition when compared to quercetin. At the species level, Acidaminococcus intestini was the only significantly enriched taxa when quercetin was supplemented, while 15 species were enriched in rice bran supplementation and 13 were enriched when quercetin and rice bran were supplemented in combination. When comparing the short chain fatty acid production, quercetin supplementation increased isobutyrate production while propionate dominated the quercetin and rice bran combined group. Higher levels of propionate were highly correlated to the lower abundance of the potentially pathogenic Enterobacteriaceae family. These findings suggest that the combination of quercetin and rice bran serve to enrich beneficial bacteria and reduce potential opportunistic pathogens. In vivo studies are necessary to determine how this synergy of quercetin and rice bran on microbiota impact host health.

Berberine combined with stachyose improves glycometabolism and gut microbiota through regulating colonic microRNA and gene expression in diabetic rats

AimsBerberine is effective for type 2 diabetes mellitus (T2DM), but has limited use in clinic. This study aims to evaluate the effect of berberine combined with stachyose on glycolipid metabolism and gut microbiota and to explore the underlying mechanisms in diabetic rats. Main methodsZucker diabetic fatty (ZDF) rats were orally administered berberine, stachyose and berberine combined with stachyose once daily for 69 days. The oral glucose tolerance and levels of blood glucose, insulin, triglyceride and total cholesterol were determined. The gut microbial profile, colonic miRNA and gene expression were assayed using Illumina sequencing. The quantitative polymerase chain reaction was used to verify the expression of differentially expressed miRNAs and genes. Key findingsRepeated treatments with berberine alone and combined with stachyose significantly reduced the blood glucose, improved the impaired glucose tolerance, and increased the abundance of beneficial Akkermansiaceae, decreased that of pathogenic Enterobacteriaceae in ZDF rats. Furthermore, combined treatment remarkably decreased the abundances of Desulfovibrionaceae and Proteobacteria in comparison to berberine. Combined treatment evidently decreased the expression of intestinal early growth response protein 1 (Egr1) and heparin-binding EGF-like growth factor (Hbegf), and significantly increased the expression of miR-10a-5p, but berberine alone not. SignificanceBerberine combined with stachyose significantly improved glucose metabolism and reshaped gut microbiota in ZDF rats, especially decreased the abundance of pathogenic Desulfovibrionaceae and Proteobacteria compared to berberine alone, providing a novel strategy for treating T2DM. The underlying mechanisms may be associated with regulating the expression of intestinal Egr1, Hbegf and miR-10a-5p, but remains further elucidation.

Distribution and molecular characterization of ESBL, pAmpC β-lactamases, and non-β-lactam encoding genes in Enterobacteriaceae isolated from hospital wastewater in Eastern Cape Province, South Africa.

Globally, there is an increasing occurrence of multidrug-resistant (MDR) Enterobacteriaceae with extended-spectrum β-lactamases (ESBLs) and/or plasmid-encoded AmpC (pAmpC) β-lactamases in clinical and environmental settings of significant concern. Therefore, we aimed to evaluate the occurrence of ESBL/pAmpC genetic determinants, and some essential non-β-lactam genetic determinants in the MDR phenotypic antimicrobial resistance in Enterobacteriaceae isolates recovered from hospital wastewater. We collected samples from two hospitals in Amathole and Chris Hani District Municipalities in the Eastern Cape Province, South Africa, within October and November 2017. Using the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF), we identified a total of 44 presumptive Enterobacteriaceae isolates. From this, 31 were identified as the targeted Enterobacteriaceae members. Thirty-six percent of these belonged to Klebsiella oxytoca, while 29% were Klebsiella pneumoniae. The other identified isolates included Citrobacter freundii and Escherichia coli (10%), Enterobacter asburiae (6%), Enterobacter amnigenus, Enterobacter hormaechei, and Enterobacter kobei (3%). We established the antibiotic susceptibility profiles of these identified bacterial isolates against a panel of 18 selected antibiotics belonging to 11 classes were established following established guidelines by the Clinical and Laboratory Standard Institute. All the bacterial species exhibited resistance phenotypically against at least four antibiotic classes and were classified as MDR. Notably, all the bacterial species displayed resistance against cefotaxime, ampicillin, nalidixic acid, and trimethoprim-sulfamethoxazole. The generated multiple antibiotic resistance indices ranged between 0.5 to 1.0, with the highest value seen in one K. oxytoca isolated. Molecular characterization via the Polymerase Chain Reaction uncovered various ESBLs, pAmpCs, and other non-β-lactam encoding genes. Of the phenotypically resistant isolates screened for each class of antibiotics, the ESBLs detected were blaCTX-M group (including groups 1, 2, and 9) [51.6% (16/31)], blaTEM [32.3% (10/31)], blaOXA-1-like [19.4% (6/31)], blaSHV [12.9% (4/31)], blaPER [6.5% (2/31)], blaVEB [3.2% (1/31)], blaOXA-48-like and blaVIM [15.4% (2/13)], and blaIMP [7.7% (1/13)]. The pAmpC resistance determinants detected were blaCIT [12.9% (4/31)], blaFOX [9.7% (3/31)], blaEBC [6.5% (2/31)], and blaDHA [3.2% (1/31)]. The frequencies of the non-β-lactam genes detected were catII [79.2% (19/24)], tetA [46.7% (14/30)], sulI and sulII [35.5% (11/31)], tetB [23.3% (7/30)], aadA [12.9% (4/31)], tetC [10% (3/30)], and tetD [3.3% (1/30)]. These results indicate that hospital wastewater is laden with potentially pathogenic MDR Enterobacteriaceae with various antibiotic resistance genes that can be spread to humans throughout the food chain, provided the wastewaters are not properly treated before eventual discharge into the environment.

Species distribution of Enterobacteriaceae and non-Enterobacteriaceae responsible for urinary tract infections at the Zainoel Abidin Hospital in Banda Aceh, Indonesia

Abstract. Suhartono S, Mahdani W, Hayati Z, Nurhalimah N. 2021. Species distribution of Enterobacteriaceae and non-Enterobacteriaceae responsible for urinary tract infections at the Zainoel Abidin Hospital in Banda Aceh, Indonesia. Biodiversitas 22: 3313-3318. Urinary tract infection (UTI) is an infection that occurs along the urinary tract caused by pathogenic bacteria. Enterobacteriaceae and non-Enterobacteriaceae are generally normal flora originating from the large intestine and vaginal mucosa. This study aimed to assess the distribution of Enterobacteriaceae and non -Enterobacteriaceae pathogens that cause UTI based on species diversity, patient age, gender, and hospital units, and to evaluate their antibiotic sensitivity to uropathogens in ZAH. In total, there were 284 isolates classified as UTI pathogens with 178 Enterobacteriaceae isolates dominated by Escherichia coli and 107 non- Enterobacteriaceae isolates. Non- Enterobacteriaceae consisted of 77 isolates of Gram-positive dominated by Enterococcus faecalis and Enterococcus facium, and 29 isolates of Gram-negative dominated by Acinetobacter baumannii. The highest UTI ratio was found in the elderly (56-65 years), namely 66.2% Enterobacteriaceae and 33.8% non-Enterobacteriaceae isolates. Based on gender, females were infected with Enterobacteriaceae (66.86%) and non-Enterobacteriaceae (37.41%). Most of UTI patients in the internal medicine unit were infected with Enterobacteriaceae (55.36%) and non-Enterobacteriaceae (44.64%). Amikacin, meropenem, and levofloxacin were antibiotics that had high sensitivity against Enterobacterial and non-Enterobacterial uropathogens. The emergence of Gram-positive uropathogens need to be concerned as these groups start emerging. It is also important to monitor regularly the antibiotic susceptibility of bacterial UTI pathogens to ensure the efficacy of current UTI treatments and minimize the UTI incidence in nosocomial settings.

Detection of Colistin Resistance in Carbapenem Resistant Enterobacteriaceae by Reference Broth Microdilution and Comparative Evaluation of Three Other Methods.

Objective Challenges in susceptibility testing of colistin along with increase in the prevalence of colistin-resistant carbapenemase-producing Enterobacteriaceae (CRE) pathogens needs addressal. Evaluation of user-friendly methods is necessary as an alternative to broth microdilution (BMD), the reference susceptibility testing method, for routine implementation in diagnostic clinical microbiology laboratories. Genotypic detection of the plasmid-mediated colistin resistance is also needed for infection control purposes. Materials and Methods Colistin susceptibility of 200 nonduplicate clinical CRE isolates from December 2017 to June 2019 was determined by BMD, agar dilution (AD), E test, and rapid polymyxin NP test and interpreted as per the European Committee on Antimicrobial Susceptibility Testing. The results of AD, E test, and NP test were compared with that of BMD, considering minimal inhibitory concentration (MIC) ≤ 2 µg/mL as susceptible and > 2 µg/mL as resistant. Presence of any plasmid-mediated colistin resistance (mcr-1 and 2) was evaluated in 27 colistin-resistant CRE isolates by polymerase chain reaction. Statistical Analysis Performance of different phenotypic methods was analyzed by comparing MIC results of AD and E test with that of reference BMD method. Agreement between BMD and the other two methods was expressed in terms of categorical agreement and essential agreement. Errors were expressed as very major error (VME: false-susceptible) and major error (ME: false-resistance) by AD/E test. VME and ME of 3% disagreement were considered unacceptable. Results Colistin resistance was found in 27 (13.5%) isolates by BMD method. The VME rates of both AD (11%) and E test (37%) could not meet the Clinical and Laboratory Standards Institute recommendation (< 3% VME rate is acceptable) as alternative tests to the reference BMD. Colistin NP test showed sensitivity and specificity of 85% and 98%, respectively. The percentage discordant result in NP test was highest in Enterobacter spp. (17%). None of the 27 colistin resistant isolates showed presence of mcr-1 and mcr-2 genes. Conclusion High VME rate in AD and E tests precludes their use as alternatives to BMD for colistin susceptibility testing. NP test with moderate sensitivity but excellent specificity can be a good alternative for testing colistin susceptibility in CRE isolates, except in Enterobacter spp. Absence of mcr-1 and mcr-2 gene necessitates the exploration of other mechanisms of colistin resistance.

Antimicrobial Resistance in Enterobacteriaceae Bacteria Causing Infection in Trauma Patients: A 5-Year Experience from a Tertiary Trauma Center.

Introduction Multiple drug resistance emergences among bacteria at an alarming rate worldwide are posing a serious threat to the treatment benefits that have been achieved with antibiotics. This crisis is due to the inappropriate and overuse of existing antibiotics. We evaluated the antimicrobial resistance pattern of Enterobacteriaceae pathogens isolated from intensive care units (ICUs), wards, and outpatient department (OPD) patients. Objectives The aim of the study is to determine the antimicrobial resistance pattern in bacteria of Enterobacteriaceae family. Material and Methods This is a retrospective study conducted at a tertiary care level-1 trauma center in the capital city of India. We collected all the retrospective data of 5 years from the laboratory information system software of the microbiology laboratory. The retrospective data included patients’ details, samples detail, organism’s identification, and their antimicrobial susceptibility testing, done by Vitek2 compact system and disk diffusion test according to each year’s Clinical and Laboratory Standards Institute (CLSI) guidelines. This study included the interpretation of zone diameters and minimum inhibitory concentrations of all isolates according to CLSI guidelines, 2018. Results Among all the Enterobacteriaceae , Klebsiella spp. was the most commonly isolated pathogen, followed by Escherichia coli and Enterobacter spp. in ICUs and wards, while in OPD patients E. coli was the most commonly isolated pathogen, followed by Klebsiella spp. and Enterobacter spp. Enterobacteriaceae isolates remained resistant to all classes of cephalosporins in all settings. In addition, β lactam and β-lactamase inhibitor remained less effective. Carbapenems showed less resistance than quinolones and aminoglycosides. Among the different antimicrobial agents, tigecycline proved most effective in all settings; however, it showed more resistance than other studies. Conclusion Tigecycline proved effective among different multidrug resistance bacteria. Multidrug resistance in bacteria leads to prolonged hospital stays as well as makes the treatment less cost effective. Proper and judicious use of antimicrobials is the need of the hour.

Detection of β-lactamase in Clinical samples of Prakasam District, Andhra Pradesh

The public health complexity globally the pathogenic Enterobacteriaceae are particularly Escherichia coli and Klebsiella pneumoniae, from the hospital samples isolates of E. coli and Klebsiella spp. 520 samples were obtained from patients in prakasam (DT), Coastal Andhra, Andhra Pradesh, India. Identified under clinical laboratory condition, for microbial culture Blood agar and MacConkey agar used and identified for selected pathogens, different biochemical test was tested against microbes. Results are in urine sample examined for this study screened (520), among them culture +ve (250), β-lactamase (33), E. coli (15), Klebsiella (18) and others (217), in blood samples was collected and analyzed (250) culture +ve are (25), β-lactamase (13), E. coli (6), Klebsiella (4) and others (15). Pleural fluids (10) are evaluated among them culture +ve (3), β-lactamase (2), E. coli didn’t observed, Klebsiella (2) and others (1) also obtained (Fig. 6). In synovial fluid samples (10) screened and evaluated among them culture +ve (3), β-lactamase (3), E. coli didn’t observed, Klebsiella (3) and others also didn’t find out. In antibiotic sensitivity test, observed that sensitive to Piperacillin tazobactum and Sensitive to imepenam. Concluded that the urine samples collected and examined in different methods β-lactamase, E. coli didn’t observed, Klebsiella identified and characterized in different confirmatory analysis, use of these antibiotics is compulsory to decrease the extend of these challenging strains.

The Outbreak of Foodborne Disease by Pathogenic Enterobacteriaceae Antimicrobial Resistance - A Review

Chemicals, bacteria, viruses, and parasites can cause contamination of food. The general signs and symptoms of food poisoning include vomiting, diarrhea, headache, abdominal cramps, and fever. Paralysis and death could occur in severe infection. Most cases of food poisoning in Saudi Arabia are caused by the Enterobacteriaceae family of bacteria which is comprised of Shigella, Salmonella, and Escherichia coli. Most medications that are used to treat infections that are caused by these bacteria have become ineffective due to resistance. Escherichia coli reaches intestines due to fecal-oral contamination, consuming contaminated food, animal products, and water. Affected individuals present with fever, bloody diarrhea, vomiting, kidney failure, and hemolytic uremic syndrome. Some strains do not cause fever. Food hygiene is the best way of breaking the transmission cycle of Escherichia coli. Salmonella typhi is the causative agent of typhoid fever. The clinical picture of the affected individuals includes typhoid and non-typhoid symptoms. Typhoid symptoms include high fever, stomach pain, weakness, cough, diarrhea, and loss of appetite. On the other hand, non-typhoid signs are comprised of fever, septicemia, and prostration. Food contamination by Shigella spp. culminates in fever, cramps, diarrhea, and bloody stool. The microbe gets into healthy humans through contaminated food, tools, and water or via direct contact (like in sexual intercourse). Effective management of food poisoning entails rehydration, use of antibiotics, and encouraging adequate rest for the affected patients. One challenge that is likely to hamper the current treatment modality is the microbial resistance that the microbes have gained. Thus, new drugs have to be developed. The objectives and aims are to investigate the current biohazard of these types of microbes on foods and human safety in the Kingdom of Saudi Arabia and across the world, as well as to identify mutated and antibiotic-resistant types.

Epidemiological Characteristics and Predisposing Factors for Surgical Site Infections Caused by Bacterial Pathogens Exhibiting Multidrug-Resistant Patterns.

Background: Surgical site infection is the most common kind of nosocomial infection in developed and developing countries. Objectives: Our aim was to identify the prevalence of factors predisposing to multidrug resistance and the antimicrobial susceptibility profile of pathogens. Method: This retrospective study enrolled 10,878 patients who underwent operations in 2018–2020. Pathogens were identified using eosin methylene blue agar. Mueller–Hinton agar was used to assess antimicrobial sensitivity and resistance. In total, 382 patients with confirmed surgical site infection (SSI), whose culture showed growth, were included in the study. Results: The prevalence of SSI in the current study was 3.5%. Escherichia coli was the predominant pathogen (35.8%), followed by Staphylococcus aureus (21.8%). Antibiotic use, chronic renal failure, diabetes, and emergency operations were found to increase the likelihood of multidrug resistance (OR = 6.23, CI = 1.443–26.881, p = 0.014; OR = 5.67, CI = 1.837–19.64, p = 0.02; OR = 2.54, CI = 1.46–7.35, p = 0.03; OR = 1.885, CI = 1.067–3.332, p = 0.002, respectively). The pathogens showed different levels of antimicrobial resistance against ceftriaxone (72.7%), ciprofloxacin (46.6%), and gentamicin (34%). Antimicrobial resistance of about 1–3.4% was exhibited by linezolid, tigecycline, and teicoplanin. Conclusion: The study presented significantly increased multidrug-resistant (MDR) Enterobacteriaceae pathogens isolated from surgical sites. They involve significant morbidity and mortality rates and increased health-related costs.

Missense Mutations in the CrrB Protein Mediate Odilorhabdin Derivative Resistance in Klebsiella pneumoniae.

NOSO-502 is a preclinical antibiotic candidate of the Odilorhabdin class. This compound exhibits activity against Enterobacteriaceae pathogens, including carbapenemase-producing bacteria and most of the Colistin (CST)-resistant strains. Among a collection of CST-resistant Klebsiella pneumoniae strains harboring mutations on genes pmrAB, mgrB, phoPQ, and crrB, only those bearing mutations in gene crrB were found to be resistant to NOSO-502.CrrB is a histidine kinase which acts with the response regulator CrrA to modulate the PmrAB system, which finally induces the restructuring of the lipopolysaccharide present on the outer membrane and thus leading to CST resistance. Moreover, crrB mutations also enhance the transcription of neighboring genes such as H239_3063, an ABC transporter transmembrane region; H239_3064, a putative efflux pump also known as KexD; and H239_3065, a N-acetyltransferase.To elucidate the mechanism of resistance to NOSO-502 induced by CrrB missense mutations in K. pneumoniae, mutants of NCTC 13442 and ATCC BAA-2146 strains resistant to NOSO-502 and CST with single amino acid substitutions in CrrB (S8N, F33Y, Y34N, W140R, N141I, P151A, P151L, P151S, P151T, F303Y) were selected. Full susceptibility to NOSO-502 was restored in crrA or crrB deleted K. pneumoniae NCTC 13442 CrrB(P151L) mutants, confirming the role of CrrAB in controlling this resistance pathway. Deletion of kexD (but no other neighboring genes) in the same mutant also restored NOSO-502-susceptibility. Upregulation of the kexD gene expression was observed for all CrrB mutants. Finally, plasmid expression of kexD in a K. pneumoniae strain missing the locus crrABC and kexD significantly increased resistance to NOSO-502.

Effect of low-iron micronutrient powder (MNP) on the composition of gut microbiota of Bangladeshi children in a high-iron groundwater setting: a randomized controlled trial

PurposeAdverse effects of iron fortification/supplements such as Micronutrient Powder (MNP) on gut microbiota have previously been found in infection-prone African settings. This study examined the adversaries of a low-iron MNP compared with the standard MNP on the composition of gut microbiota in Bangladeshi children exposed to a high concentration of iron from potable groundwater.MethodsA randomized controlled trial was conducted in 2- to 5-year-old children, drinking groundwater with a high concentration of iron (≥ 2 mg/L). Children were randomized to receive one sachet per day of either standard MNP (12.5 mg iron) or low-iron MNP (5 mg iron), for 2 months. A sub-sample of 53 children was considered for paired assessment of the gut microbiome by 16S rRNA amplicon sequencing.ResultsAt baseline, the gut microbiota consisted of Bifidobacteriaceae (15.6%), Prevotellaceae (12.2%), Lactobacillaceae (3.6%), Clostridiaceae (4.1%) and Enterobacteriaceae (2.8%). Overall, there was no significant treatment effect of the low-iron MNP compared to the standard MNP. However, an apparent treatment effect was observed in children with a relative adult-like microbiota, with a higher relative abundance of potentially pathogenic Enterobacteriaceae after receiving the standard MNP compared to the low-iron MNP. This effect, however, was statistically non-significant (p = 0.07).ConclusionIn Bangladeshi children drinking iron-rich groundwater, a low-iron MNP supplementation did not have a significant impact on their gut microbiota profile/composition compared to the standard MNP.The trial registration number is ISRCTN60058115; Date of registration 03/07/2019; retrospectively registered.

Potato Arabinogalactan Acts as Prebiotics by A Simple Extraction

The effect of the extracting procedures for potato pulp arabinogalactan were investigated on the growth of gut-microflora by in vitro experiments. Crude saccharides (CS) were prepared by 50 g dried potato pulp suspended in 1 L of pure water. The suspensions were autoclaved at 1211C for 2 h, and filtered by a filter paper. The filtrate were concentrated around 1/4 by a rotary evaporator, and aggregated by 4× volume of ethanol. Dialyzed saccharides (DS) were prepared to dialyzed CS by a dialysis membrane (cut off MW &lt; 10,000). Enzyme-treated saccharides (ES) were prepared to digest CS by a crude amylase, Gruku-Gin (Amano Enzyme) and dialyzed. All saccharides were lyophilized or heat-dried to store. According to size-exclusion chromatography, the molecular distribution of CS were between 400 and 200,000. A peak of oligosaccharides was observed around MW 800. The peak were disappeared in charts of DS and ES. Glucan were occupied 50% in the total amount of glycan in CS and DS, and decreased to approx. 5% in ES. When thirteen strains of gut microbes were cultivated in GAM broth including the saccharides instead of glucose, CP and EP selectively stimulated several non-pathogenic Bifidobacterium and Clostridium, but not pathogenic Enterobacteriaceae.

Harnessing Iron Acquisition Machinery to Target Enterobacteriaceae.

Infections caused by Gram-negative bacteria can be challenging to treat due to the outer membrane permeability barrier and the increasing emergence of antibiotic resistance. During infection, Gram-negative pathogens must acquire iron, an essential nutrient, in the host. Many Gram-negative bacteria utilize sophisticated iron acquisition machineries based on siderophores, small molecules that bind iron with high affinity. In this review, we provide an overview of siderophore-mediated iron acquisition in Enterobacteriaceae and show how these systems provide a foundation for the conceptualization and development of approaches to prevent and/or treat bacterial infections. Differences between the siderophore-based iron uptake machineries of pathogenic Enterobacteriaceae and commensal microbes may lead to the development of selective "Trojan-horse" antimicrobials and immunization strategies that will not harm the host microbiota.

Analysis of Community-Acquired Urinary Tract Infection Treatment in Pediatric Patients Requiring Hospitalization: Opportunity for Use of Narrower Spectrum Antibiotics.

Background: The most narrow-spectrum antibiotic possible should be used for empiric and definitive treatment of pediatric urinary tract infections (UTIs). Objectives: The objectives of this study were to determine an appropriate narrow-spectrum antibiotic for empiric UTI treatment, factors differentiating empiric first-generation cephalosporin (FGC) versus third-generation cephalosporin (TGC) coverage, and factors associated with unnecessarily broad-spectrum definitive antibiotic treatment. Methods: This was a retrospective chart review of children admitted from 2013 to 2015 who were diagnosed with a UTI and received treatment. Multivariable logistic regression assessed independent factors associated with our outcomes. Results: Of 568 diagnosed UTIs, 88.6% received empiric TGC treatment. Empiric coverage among cultured organisms was only 5.4% lower in FGC versus TGC. Adolescent age group (odds ratio [OR] = 8.83, 95% confidence interval [CI] = 1.47-53.11), uncircumcised males (OR = 4.52, 95% CI = 1.27-16.08), Hispanic ethnicity (OR = 4.37, 95% CI = 1.14-16.82), and hospitalization within the preceding 3 months (OR = 4.73, 95% CI = 1.38-16.23) were associated with FGC nonsusceptibility among TGC susceptible Enterobacteriaceae pathogens. De-escalation occurred in 55.8% of diagnosed UTIs eligible for de-escalation at discharge. Urine white blood cell (WBC) count >5 (OR = 2.89, 95% CI = 1.14-7.21), serum WBC count (OR = 1.04, 95% CI = 1.01-1.07), and having only one narrow-spectrum treatment option (OR = 5.1, 95% CI = 2.43-10.66) were associated with unnecessarily broad-spectrum definitive treatment. Conclusion and Relevance: FGC would be an appropriate narrow-spectrum empiric agent for UTIs at our institution. The factors associated with FGC nonsusceptibility can further stratify empiric treatment decisions. The factors associated with unnecessarily broad-spectrum definitive treatment illustrate areas for educational efforts and future research regarding UTI treatment.

Characterization of the first highly predatory Bdellovibrio bacteriovorus from Iran and its potential lytic activity against principal pathogenic Enterobacteriaceae.

Objective(s): Bdellovibrio-and-like organisms (BALOs) are predatory prokaryotes that attack and kill other Gram-negative bacteria for growth and reproduction. This study describes the isolation, identification, biological properties, and bacteriolytic activity of the first Bdellovibrio bacteriovorus with a broad prey range from Iran.Materials and Methods:One BALO strain with high predatory potency was isolated from the rhizosphere soil using Enteropathogenic Escherichia coli as prey. It was identified and designated as Bdellovibrio bacteriovorus strain SOIR-1 through plaque assays, transmission electron microscopy (TEM), Bdellovibrio-specific PCRs, and 16S rRNA gene sequence analysis. Biological characterization and analysis of bacteriolytic activity were also performed.Results:TEM and Bdellovibrio-specific PCRs confirmed that the strain SOIR-1 belongs to the genus Bdellovibrio. Analysis of the 16S rRNA gene sequence revealed its close phylogenetic relationship with strains of Bdellovibrio bacteriovorus. The strain SOIR-1 grew within the temperature range of 25–37 °C and the pH range of 6.0–8.0, with the optimal predatory activity at 30 °C and pH 7.4. It had the highest and lowest bacteriolytic activity toward Shigella dysenteriae and Pseudomonas aeruginosa with a killing rate of 89.66% and 74.83%, respectively. Conclusion:Considering the hypothesis of bdellovibrios heterogeneity, identification of new isolates contributes to a deeper understanding of their diversity, their ecological roles, and their promising potential as living antibiotics or biocontrol agents. Bdellovibrios with broad bacteriolytic nature has not previously been reported in sufficient detail from Iran. The results of this study showed the great potential of native B. bacteriovorus strain SOIR-1 in the control and treatment of diseases caused by pathogenic Enterobacteriaceae.

Endocannabinoids Inhibit the Induction of Virulence in Enteric Pathogens

Endocannabinoids are host-derived lipid hormones that fundamentally impact gastrointestinal (GI) biology. The use of cannabis and other exocannabinoids as anecdotal treatments for various GI disorders inspired the search for mechanisms by which these compounds mediate their effects, which led to the discovery of the mammalian endocannabinoid system. Dysregulated endocannabinoid signaling was linked to inflammation and the gut microbiota. However, the effects of endocannabinoids on host susceptibility to infection has not been explored. Here, we show that mice with elevated levels of the endocannabinoid 2-arachidonoyl glycerol (2-AG) are protected from enteric infection by Enterobacteriaceae pathogens. 2-AG directly modulates pathogen function by inhibiting virulence programs essential for successful infection. Furthermore, 2-AG antagonizes the bacterial receptor QseC, a histidine kinase encoded within the core Enterobacteriaceae genome that promotes the activation of pathogen-associated type three secretion systems. Taken together, our findings establish that endocannabinoids are directly sensed by bacteria and can modulate bacterial function.

Near-Infrared Spectroscopy Evaluations for the Differentiation of Carbapenem-Resistant from Susceptible Enterobacteriaceae Strains.

Antimicrobial Resistance (AMR) caused by Carbapenem-Resistant Enterobacteriaceae (CRE) is a global threat. Accurate identification of these bacterial species with associated AMR is critical for their management. While highly accurate methods to detect CRE are available, they are costly, timely and require expert skills, making their application infeasible in low-resource settings. Here, we investigated the potential of Near-Infrared Spectroscopy (NIRS) for a range of applications: (i) the detection and differentiation of isolates of two pathogenic Enterobacteriaceae species, Klebsiella pneumoniae and Escherichia coli, and (ii) the differentiation of carbapenem resistant and susceptible K. pneumoniae. NIRS has successfully differentiated between K. pneumoniae and E. coli isolates with a predictive accuracy of 89.04% (95% CI; 88.7–89.4%). K. pneumoniae isolates harbouring carbapenem-resistance determinants were differentiated from susceptible K. pneumoniae strains with an accuracy of 85% (95% CI; 84.2–86.1%). To our knowledge, this is the largest proof of concept demonstration for the utility and feasibility of NIRS to rapidly differentiate between K. pneumoniae and E. coli as well as carbapenem-resistant K. pneumoniae from susceptible strains.