The present study examined the anti-biofilm efficacy of two short-chain antimicrobial peptides (AMPs), namely, indolicidin and cecropin A (1-7)-melittin (CAMA) against biofilm-forming ...multidrug-resistant enteroaggregative Escherichia coli (MDR-EAEC) isolates. The typical EAEC isolates re-validated by PCR and confirmed using HEp-2 cell adherence assay was subjected to antibiotic susceptibility testing to confirm its MDR status. The biofilm-forming ability of MDR-EAEC isolates was assessed by Congo red binding, microtitre plate assays and hydrophobicity index; broth microdilution technique was employed to determine minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentrations (MBECs). The obtained MIC and MBEC values for both AMPs were evaluated alone and in combination against MDR-EAEC biofilms using crystal violet (CV) staining and confocal microscopy-based live/dead cell quantification methods. All the three MDR-EAEC strains revealed weak to strong biofilm-forming ability and were found to be electron-donating and weakly electron-accepting (hydrophobicity index). Also, highly significant (P < 0.001) time-dependent hydrodynamic growth of the three MDR-EAEC strains was observed at 48 h of incubation in Dulbecco's modified Eagle's medium (DMEM) containing 0.45% D-glucose. AMPs and their combination were able to inhibit the initial biofilm formation at 24 h and 48 h as evidenced by CV staining and confocal quantification. Further, the application of AMPs (individually and combination) against the preformed MDR-EAEC biofilms resulted in highly significant eradication (P < 0.001) at 24 h post treatment. However, significant differences were not observed between AMP treatments (individually or in combination). The AMPs seem to be an effective candidates for further investigations such as safety, stability and appropriate biofilm-forming MDR-EAEC animal models.
A total of 98 previously characterized and serotyped L. monocytogenes strains, comprising 32 of 1/2a; 20 of 1/2b and 46 of 4b serotype, from clinical and food sources were studied for their ...capability to form a biofilm. The microtiter plate assay revealed 62 (63.26%) strains as weak, 27 (27.55%) strains as moderate, and 9 (9.18%) strains as strong biofilm formers. Among the strong biofilm formers, 6 strains were of serotype 1/2a and 3 strains were of serotype 1/2b. None of the strain from 4b serotype exhibited strong biofilm formation. No firm correlation (p = 0.015) was noticed between any serotype and respective biofilm formation ability. Electron microscopic studies showed that strong biofilm forming isolates could synthesize a biofilm within 24 h on surfaces important in food industries such as stainless steel, ceramic tiles, high-density polyethylene plastics, polyvinyl chloride pipes, and glass. Cell enumeration of strong, moderate, and weak biofilm was performed to determine if the number of cells correlated with the biofilm-forming capabilities of the isolates. Strong, moderate, and weak biofilm showed 570 plus or minus 127 103 cells/cm2, 33 plus or minus 26 103 cells/cm2, 5 plus or minus 3 103 cells/cm2, respectively, indicating that the number of cells was directly proportional to the strength of the biofilm. The hydrophobicity index (HI) analysis revealed higher hydrophobicity with an increased biofilm formation. Fatty acid methyl esterase analysis revealed the amount of certain fatty acids such as iso-C15:0, anteiso-C15:0, and anteiso-C17:0 fatty acids correlated with the biofilm-forming capability of L. monocytogenes. This study showed that different strains of L. monocytogenes form biofilm of different intensities which did not completely correlate with their serotype; however, it correlated with the number of cells, hydrophobicity, and amount of certain fatty acids.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The present study successfully synthesized nano CoAl2O4 by the solution combustion method, employing sucrose as an ergonomic fuel. The synthesis of CoAl2O4 was confirmed by X-ray diffraction, Raman ...spectroscopy as well as electron microscopy, and a mean size of 70–80 nm was observed. Besides, the antioxidant, antimicrobial, photocatalytic and antibiofilm potentials of nano CoAl2O4 were evaluated against multi-drug resistant (MDR) bacterial strains. Initially, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CoAl2O4 (µg/mL) were determined to be within the ranges of 62.50–250 and 250–500, respectively. The poultry red blood cell-based hemolysis and secondary cell line-based MTT assays revealed concentration-dependent toxicity with an inhibitory concentration-50 (µg/mL) of 75.0 and 25.0 against MDA-MB468 and HT29 cell lines, respectively. Interestingly, CoAl2O4 was found to generate reactive oxygen species and revealed potential antioxidant properties by DPPH and reducing power assays. Moreover, the synthesized materials permeabilized the membranes of both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and were found to be bactericidal and exhibited antibiofilm activity against the MDR- E. coli strain. The nano CoAl2O4, when treated with the MIC and 1/2X MIC, eliminated MDR-methicillin-resistant S. aureus within 60 and 120 min, respectively, and was found to be an excellent photosensitizer. In short, this study concludes that CoAl2O4 was found to be a promising antimicrobial candidate with antioxidant as well as antibiofilm properties for application in wastewater treatment and therapeutic purposes.
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Numerous studies have demonstrated that targeting Ag to Fc receptors (FcR) on APCs can enhance humoral and cellular immunity. However, studies are lacking that examine both the use of FcR-targeting ...in generating immune protection against infectious agents and the use of FcRs in the induction of mucosal immunity.
Francisella tularensis
is a category A intracellular mucosal pathogen. Thus, intense efforts are underway to develop a vaccine against this organism. We hypothesized that protection against mucosal infection with
F. tularensis
would be significantly enhanced by targeting inactivated
F. tularensis
live vaccine strain (iFt) to FcRs at mucosal sites, via intranasal immunization with mAb-iFt complexes. These studies demonstrate for the first time that: 1) FcR-targeted immunogen enhances immunogen-specific IgA production and protection against subsequent infection in an IgA-dependent manner, 2) FcγR and neonatal FcR are crucial to this protection, and 3) inactivated
F. tularensis
, when targeted to FcRs, enhances protection against the highly virulent SchuS4 strain of
F. tularensis
, a category A biothreat agent. In summary, these studies show for the first time the use of FcRs as a highly effective vaccination strategy against a highly virulent mucosal intracellular pathogen.
The present study assessed the presence of ESBL-producing
Escherichia coli
in livestock farm wastewater (LFWW), hospital wastewater (HWW), and natural water sources (NWS) from five districts ...(Prayagraj, Mirzapur, Varanasi, Sonbhadra, and Jaunpur) of eastern parts of Uttar Pradesh, India (
n
= 134). Phenotypic ESBL production among cefotaxime-resistant
E. coli
isolates (91.29%, 283/310) was significantly different (
p
< 0.05) in the samples from Jaunpur and Sonbhadra, but not from Prayagraj, Mirzapur and Varanasi (
p
> 0.05). The MIC of cefotaxime and ceftazidime against these isolates were in the ranges of 64–512 µg/mL and 16–512 µg/mL, respectively. Genotypically, 38.51% (109/283) of the isolates harbored at least one or more plasmid-mediated ESBL-genes, of which,
bla
CTX-M-gr-1
was the predominant (90.82%, 99/109), followed by
bla
TEM
(73.39%, 80/109). A non-significant difference (
p
> 0.05) was observed in the occurrence of ESBL genes among the phenotypically positive isolates of different sampling places. Multidrug-resistant (MDR) traits were observed in 105 (96.33%) of 109 tested isolates with a MAR index ranging from 0.31 to 1.0. Absolute resistance (100%) was evident against azithromycin for all isolates recovered from Varanasi, Prayagraj, and Sonbhadra irrespective of their sources. The majority of the isolates belonged to commensal phylogroup A (40.37%, 44/109) and B1 (27.44%, 31/109), while only two isolates recovered from HWW sources of Varanasi belonged to the extra-intestinal pathogenic phylogroup B2. These findings suggested that the wastewater and natural water sources of eastern parts of Uttar Pradesh, India, harbored a high magnitude of MDR-ESBL
E. coli
with the potential to be transmitted to humans and animals.
A total of 38 Escherichia coli isolates were recovered from 120 samples collected from various sources of broiler chicken farms (n = 10 each) in Andhra Pradesh and Telangana states. Though the ...recovered E. coli isolates were found variably resistant to the tested antibiotics, all the tested isolates were susceptible to meropenem. Alarming multi-drug resistance (MDR) was observed (34/38) among the recovered isolates, wherein antibiotic-resistant genes (blaTEM, blaSHV, and tetA) were detected, except for blaCTX-M-9. The heatmap with cluster analysis exhibited that majority of the E. coli isolates recovered from different sources and regions clustered together based on their phenotypic resistance suggesting co-sharing of resistance. However, the pulsed-field gel electrophoresis (PFGE) typing revealed an extremely diverse genotypic profile. Further, a significant statistical association was not observed between hypothesized risk factors and recovered MDR- E. coli isolates from various sources, although a significant statistical association between antibiotic resistance with large flock size, poor biosecurity practices, poor workers’ hygiene, and poor disinfection practices was noticed. Since the study highlighted an alarming level of drug resistance among the recovered E. coli isolates, further in-depth research in similar veins is required to ensure the prudent use of antimicrobials in the poultry sector and the implementation of an antimicrobial surveillance system.
•E. coli isolates from broiler chicken farms exhibited alarming MDR profile.•E. coli isolates harbored tetA, blaTEM, blaSHV genes.•Majority of the isolates clustered together suggesting co-sharing of resistance.•PFGE pattern exhibited extremely diverse genotypic profile.•In-depth risk analysis is warranted to ensure prudent use of antimicrobials in poultry.
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