Exploring the action of new FimH inhibitors against CTX– 15 enzyme by enzoinformatics approach: A plausible arsenal against drug-resistant uropathogenic bacterial strains

Purpose: To explore the potency of FimH inhibitors against CTX-M β-lactamase enzyme type 15, in view of the increasing prevalence of CTX-M 15 in uropathogenic strains which has reduced the treatment options to minimal.Method: FimH inhibitors were targeted against CTXM-15 by a molecular docking approach. Thereafter, the best ligand-target confirmation was selected and analyzed using LIGPLOT+ Version v.2.1. The hydrophobic and hydrogen bonding among the catalytic site amino acids of CTXM-15 and the FimH inhibitors were analyzed and 3-D structures were converted into 2-D images by LIGPLOT algorithm.Results: Out of all the FimH inhibitors tested, 3′-chloro-4′- (α-D-mannopyranosyloxy) biphenyl-4- carbonitrile, para-biphenyl-2-methyl-3′-methylamidemannoside, para-biphenyl-2-methyl-3′,5′dimethylamide-α-D-mannoside, and thiazolylamino mannoside exhibited better interaction with the CTX-M15 active site than the positive control avibactam. Moreover, in CTX-M 15, the amino acid residues, Ser70, Tyr105, Ser130, Asn132, Thr216, Thr235, Gly236, and Ser237 were commonly interacting with these FimH inhibitors as well as avibactam.Conclusion: The predicted findings suggest that these FimH inhibitors could be explored as potential CTX-M 15 inhibitors to cope-up with resistance issues of uropathogenic bacteria in the form of an alternate strategy.

Are Uropathogenic Bacteria Living in Multispecies Biofilm Susceptible to Active Plant Ingredient—siatic Acid?

Urinary tract infections (UTIs) are a serious health problem in the human population due to their chronic and recurrent nature. Bacteria causing UTIs form multispecies biofilms being resistant to the activity of the conventionally used antibiotics. Therefore, compounds of plant origin are currently being searched for, which could constitute an alternative strategy to antibiotic therapy. Our study aimed to determine the activity of asiatic acid (AA) against biofilms formed by uropathogenic Escherichia coli, Enterobacter cloacae, and Pseudomonas aeruginosa. The influence of AA on the survival, biofilm mass formation by bacteria living in mono-, dual-, and triple-species consortia as well as the metabolic activity and bacterial cell morphology were determined. The spectrophotometric methods were used for biofilm mass synthesis and metabolic activity determination. The survival of bacteria was established using the serial dilution assay. The decrease in survival and a weakening of the ability to create biofilms, both single and multi-species, as well as changes in the morphology of bacterial cells were noticed. As AA works best against young biofilms, the use of AA-containing formulations, especially during the initial stages of infection, seems to be reasonable. However, there is a need for further research concerning AA especially regarding its antibacterial mechanisms of action.

The Relationship between Antibiotic Susceptibility and pH in the Case of Uropathogenic Bacteria

Urinary tract infections (UTIs) are common bacterial infections caused mainly by enteric bacteria. Numerous virulence factors assist bacteria in the colonization of the bladder. Bacterial efflux pumps also contribute to bacterial communication and to biofilm formation. In this study, the phenotypic and genetic antibiotic resistance of clinical UTI pathogens such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were determined by disk diffusion method and polymerase chain reaction (PCR). Following this, different classes of antibiotics were evaluated for their antibacterial activity at pH 5, 6, 7 and 8 by a microdilution method. Gentamicin (GEN) was the most potent antibacterial agent against E. coli strains. The effect of GEN on the relative expression of marR and sdiA genes was evaluated by quantitative PCR. The slightly acidic pH (pH 6) and GEN treatment induced the upregulation of marR antibiotic resistance and sdiA QS activator genes in both E. coli strains. Consequently, bacteria had become more susceptible to GEN. It can be concluded that antibiotic activity is pH dependent and so the artificial manipulation of urinary pH can contribute to a more effective therapy of multidrug resistant bacterial infections.

Gut-bladder axis syndrome associated with recurrent UTIs in humans

Recurrent urinary tract infections (rUTIs) are a major health burden worldwide, with history of infection being a significant risk factor. While the gut is a known reservoir for uropathogenic bacteria, the role of the microbiota in rUTI remains unclear. We conducted a year-long study of women with and without history of rUTIs, from whom we collected urine, blood and monthly fecal samples for multi-omic interrogation. The rUTI gut microbiome was significantly depleted in microbial richness and butyrate-producing bacteria compared to controls, reminiscent of other inflammatory conditions, though Escherichia coli gut and bladder dynamics were comparable between cohorts. Blood samples revealed signals of differential systemic immunity, leading us to hypothesize that rUTI susceptibility is in part mediated through a syndrome involving the gut-bladder axis, comprising gut dysbiosis and differential immune response to bacterial bladder colonization, manifesting in symptoms. This work highlights the potential for microbiome therapeutics to prevent and treat rUTIs.

Screening of antimicrobial activity of aqueous and ethanolic extracts of some medicinal plants from Cameroon and assessment of their synergy with common antibiotics against multidrug-resistant uropathogenic bacteria.

Background and aim: The Cameroonian flora abounds in plants with multidimensional therapeutic virtues which can play an important role in the fight against resistance to antibiotics and the search for new antimicrobials. This study aimed to screen the antimicrobial potential of aqueous and ethanolic extracts of thirteen (13) samples (Bark, leaf, seed) of eight (8) plants from Cameroon against 3 reference pathogens and to evaluate their synergy with conventional antibiotics against eleven (11) multiresistant uropathogenic (MRU) bacteria. Method: Bioactive compounds were extracted from leaves of Leucanthemum vulgare, Cymbopogon citratus (DC.) Stapf, Moringa oleifera Lam and Vernonia amygdalina Delile; barks of Cinchona officinalis and Enantia chlorantha Oliv; barks and seeds of Garcinia lucida Vesque and leaves and seeds of Azadirachta indica (Neem) using distilled water and ethanol as solvents. The extracts were tested against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538 and Candida albicans 10231 using the well diffusion method and the microdilution method. The synergistic effect was assessed (using disc diffusion method and the checkerboard method) against MRU bacteria namely Achromobacter xylosoxidans 4892, Citrobacter freundii 426, Enterococcus avium 1669, Escherichia coli 1449, Klebsiella oxytoca 3003, Kocuria rizophilia. 1542, Moraxella catarrhalis 4222, Morganella morganii 1543, Pseudomonas aeruginosa 3057, Staphylococcus aureus 1449 and Streptococcus agalactiae 3984. Results: We found that distilled water extracted a more important mass of phytochemical compounds (7.9-21.2%) compared to ethanol (5.8-12.4%). Except C. officinalis and G. lucida leaves, the rest of extracts were active with inhibition diameters (ID) ranging from 5 to 36 mm. Both ethanolic (EE) and aqueous extract (AE) of E. chloranta bark (ECB) were the most active against all pathogens with the mean ID of 17 and 36 mm vs S. aureus ATCC 6538, 23 and 14 mm vs E. coli ATCC 25922 and 36 and 19 mm vs C. albicans ATCC 10231. Only the EE of E. chloranta bark (ECB) had a strong activity against all the microorganisms tested (MIC <2 mg / ml); L. vulgare leaves (LVL) and G. lucida seed (GLS) had moderate (average MIC of 8 mg/ml) while all other extracts showed very weak antimicrobial activity. In addition, the fractional inhibitory concentration (FIC) ranged from 0.125 to 0.750. No antagonism (FIC> 4) or indifference (1≤ FIC≤4) was noted between the extracts and the antibiotics, but the best synergies were found with ECB which well-modulated Kanamycin (FIC = 0.125 against S. aureus and 0.250 against E. coli), nitrofurantoin (FIC = 0.250 against S. aureus and 0.188 against E. coli) and ampicillin (FIC = 0.125 against E. coli). Similarly, compared to other extracts, ECB, LVL and GLS also well-modulated ampicillin, ceftazidime, tetracycline, nitrofurantoin, and trimethoprim against all the above-mentioned resistant uropathogenic bacteria with important increase in fold area (IFA). Conclusion: This study show that E. chlorantha bark, L. vulgare leaves G. lucida seed, have good antimicrobial activity against both bacteria (Gram positive and Gram negative) and fungi (C. albicans); and should be more investigated for their possible use to the fight against MDR and MRU microorganisms.

ESTIMATE THE PROPORTION OF MRSA AMONG STAPHYLOCOCCUS AUREUS ISOLATED FROM PATIENTS OF URINARY TRACT INFECTION ALONG WITH ITS ANTIBIOGRAM IN TERTIARY CARE HOSPITAL AT AGARTALA, TRIPUR

Background: Generally, gram-negative bacteria are the most common uropathogenic bacteria causing UTI, as per recent ndings gram-positive bacteria also equally responsible for the UTI. As they have a plethora of pathogenic virulence factors that are highly responsible to give rise to severe UTI infection. Moreover, a betalactamase-producing gram-positive organism such as Staphylococcus aureus is often associated with high resistance to a wide class of antibiotics. There are few studies regarding the UTI infection-causing by the multi-drug resistant strain of Staph aureus called MRSA in Tripura Northeast India. This study aimed to determine the proportion of MRSA causing UTI in Tertiary care hospitals at Agartala Tripura. Materials and method – Mid-stream urine specimens were collected from patients suspected to be having UTI. Well, the mixed sample of urine was inoculated on specic culture media and all the isolates were identied as staphylococci by Gram staining, catalase test, coagulase test, and other biochemical reactions required for the identication of S.aureus and as per the CLSI guidelines we have studied the antibiogram of S.aureus and we have detected the MRSA by cefoxitin disc diffusion method. Result: in our present study 650 midstream urine samples were collected and processed. Out of the total 650 urine samples 91(14%) yielded growth on culture media and out of the 91 positive cases Staphylococcus aureus infected UTI cases were 12(13%) and among the 12 S.aureus positive isolates 6(50%) isolates were MSSA and other 6(50%) isolates were MRSA. Here in our study vancomycin(100%), doxycycline(83%), Nitrofurantoin(100%), Linezolid(83%) found to be very effective drugs for the treatment of MRSA, and most importantly here in this region of northeast only 6.5% of the total UTI patients affected by the MRSA which means the ratio of UTI infection by MRSA is low in this region. CONCLUSION: This study will be useful to update the policy of the empirical drugs in our hospital and at the same time, it will also help to control the unnecessary use of antibiotics to treat UTI patients

The Bacteria and the Host: A Story of Purinergic Signaling in Urinary Tract Infections

The local environment forces a selection of bacteria that might invade the urinary tract, allowing only the most virulent to access the kidney. Quite similar to the diet in setting the stage for the gut microbiome, renal function determines the conditions for bacteria-host- interaction in the urinary tract. In the kidney, the term local environment or microenvironment is completely justified because the environment literally changes within a few micrometers. The precise composition of the urine is a function of the epithelium lining the microdomain, and the microenvironment in the kidney shows more variation in the content of nutrients, ion composition, osmolality, and pH than any other site of bacteria-host interaction. This review will cover some of the aspects of bacterial-host interaction in this unique setting and how uropathogenic bacteria can alter the condition for bacteria-host interaction. There will be a particular focus on the recent findings regarding how bacteria specifically trigger host paracrine signaling, via release of extracellular ATP and activation of P2 purinergic receptors. These finding will be discussed from the perspective of severe urinary tract infections, including pyelonephritis and urosepsis.