Assessment of Ceftazidime-Avibactam 30/20-µg Disk, Etest versus Broth Microdilution Results When Tested against Enterobacterales Clinical Isolates.

The objective of this research was to evaluate the correlation between inhibitory zones and MIC when testing ceftazidime-avibactam using disk diffusion, Etest, and broth microdilution method established by the Clinical and Laboratory Standards Institute (CLSI). Four-hundred and 58 isolates of Enterobacterales isolated from 54 medical centers from the China Antimicrobial Surveillance Network (CHINET) in 2016 to 2020 were collected. Antimicrobial susceptibility testing using broth microdilution, Etest, and disk diffusion were performed according to the CLSI. Of the 458 Enterobacterales, 17.2% (79/458) and 82.8%(379/458) were resistant or susceptible to ceftazidime-avibactam by broth microdilution, respectively. Compared with the broth microdilution method, the categorical agreement (CA) and essential agreement (EA) of the Etest were 99.6% (456/458) and 94.8% (434/458), respectively; the major error (ME) and very major error (VME) were both 0.2% (1/458). For disk diffusion, the CA and VME were 99.8% (457/458) and 0.2% (1/458), respectively. For Escherichia coli, the CA and EA of the Etest were 100% and 97.1% (135/139), respectively. The CA of the disk diffusion was 100%. For Klebsiella pneumoniae, the CA and EA of the Etest were 99.3% (288/290) and 93.4% (271/290), respectively, the ME and VME were both 0.3% (1/290). The CA and VME of disk diffusion were 99.7% (289/290) and 0.3% (1/290), respectively. For other Enterobacterales, the CA and EA of the Etest were 100% and 96.6% (28/29), respectively. The CA of the disk diffusion was 100%. Ceftazidime-avibactam disk diffusion (30/20-µg disks) and Etest demonstrated good performance for ceftazidime-avibactam susceptibility testing against Enterobacterales clinical isolates. IMPORTANCE Multidrug-resistant Gram-negative bacteria, especially for extended-spectrum ß-lactamases-producing and carbapenemase-producing Enterobacterales, are disseminating rapidly around the world. Treatment options for these infections are limited, which prompt the development of novel or combinational therapies to combat the infections caused by multidrug-resistant pathogens. The newly available ß-lactam combination agent ceftazidime-avibactam has been demonstrated good in vitro and in vivo activity against ESBL, AmpC, KPC-2, or OXA-48-like-producing isolates and has shown promise in treating carbapenem-resistant Enterobacterales infections. Concerningly, there are few available automated systems for ceftazidime-avibactam susceptibility testing, and the broth microdilution method is hard to perform in most routine laboratories. Therefore, we urgently need an economical and practical method for the accurate detection of ceftazidime-avibactam activity against Gram-negative bacilli. Here, we evaluate the performance of the disk diffusion and Etest compared with the reference broth microdilution method against Enterobacterales clinical strains.

Etest ECVs/ECOFFs for Detection of Resistance in Prevalent and Three Nonprevalent Candida spp. to Triazoles and Amphotericin B and Aspergillus spp. to Caspofungin: Further Assessment of Modal Variability.

Susceptibility testing is an important tool in the clinical setting; its utility is based on the availability of categorical endpoints, breakpoints (BPs), or epidemiological cutoff values (ECVs/ECOFFs). CLSI and EUCAST have developed antifungal susceptibility testing, BPs, and ECVs for some fungal species. Although the concentration gradient strip bioMérieux Etest is useful for routine testing in the clinical laboratory, ECVs are not available for all agent/species; the lack of clinical data precludes development of BPs. We reevaluated and consolidated Etest data points from three previous studies and included new data. We defined ECOFFinder Etest ECVs for three sets of species-agent combinations: fluconazole, posaconazole, and voriconazole and 9 Candida spp.; amphotericin B and 3 nonprevalent Candida spp.; and caspofungin and 4 Aspergillus spp. The total of Etest MICs from 23 laboratories (Europe, the Americas, and South Africa) included (antifungal agent dependent): 17,242 Candida albicans, 244 C. dubliniensis, 5,129 C. glabrata species complex (SC), 275 C. guilliermondii (Meyerozyma guilliermondii), 1,133 C. krusei (Pichia kudriavzevii), 933 C. kefyr (Kluyveromyces marxianus), 519 C. lusitaniae (Clavispora lusitaniae), 2,947 C. parapsilosis SC, 2,214 C. tropicalis, 3,212 Aspergillus fumigatus, 232 A. flavus, 181 A. niger, and 267 A. terreus SC isolates. Triazole MICs for 66 confirmed non-wild-type (non-WT) Candida isolates were available (ERG11 point mutations). Distributions fulfilling CLSI ECV criteria were pooled, and ECOFFinder Etest ECVs were established for triazoles (9 Candida spp.), amphotericin B (3 less-prevalent Candida spp.), and caspofungin (4 Aspergillus spp.). Etest fluconazole ECVs could be good detectors of Candida non-WT isolates (59/61 non-WT, 4 of 6 species).

Rapid and real-time monitoring of bacterial growth against antibiotics in solid growth medium using a contactless planar microwave resonator sensor.

Infection diagnosis and antibiotic susceptibility testing (AST) are pertinent clinical microbiology practices that are in dire need of improvement, due to the inadequacy of current standards in early detection of bacterial response to antibiotics and affordability of contemporarily used methods. This paper presents a novel way to conduct AST which hybridizes disk diffusion AST with microwave resonators for rapid, contactless, and non-invasive sensing and monitoring. In this research, the effect of antibiotic (erythromycin) concentrations on test bacterium, Escherichia coli (E. coli) cultured on solid agar medium (MH agar) are monitored through employing a microwave split-ring resonator. A one-port microwave resonator operating at a 1.76 GHz resonant frequency, featuring a 5 mm2 sensitive sensing region, was designed and optimized to perform this. Upon introducing uninhibited growth of the bacteria, the sensor measured 0.005 dB/hr, with a maximum change of 0.07 dB over the course of 15 hours. The amplitude change decreased to negligible values to signify inhibited growth of the bacteria at higher concentrations of antibiotics, such as a change of 0.005 dB in resonant amplitude variation while using 45 µg of antibiotic. Moreover, this sensor demonstrated decisive results of antibiotic susceptibility in under 6 hours and shows great promise to expand automation to the intricate AST workflow in clinical settings, while providing rapid, sensitive, and non-invasive detection capabilities.

Investigation of New Inhibitors of UDP-N-Acetylglucosamine Enolpyruvyl Transferase (MurA) by Virtual Screening with Antibacterial Assessment.

BACKGROUND: Considering the interesting role in the peptidoglycan biosynthesis pathway, the enzyme UDP-N-acetylglucosamine enolpyruvyl transferase is an attractive target to develop new antibacterial agents. It catalyzes the first key step of this pathway and its inhibition leads to bacterial cell death. Fosfomycin is known as the natural inhibitor of MurA. OBJECTIVE: The study aimed to introduce new inhibitors of MurA by virtual screening of different chemical compounds libraries, and test the best scored "virtual hits" against three pathogenic bacteria: Escherichia coli, Bacillus subtilis and Staphylococcus aureus. METHODS: A virtual screening of the structural analogues of fosfomycin downloaded from the Pub- Chem database was performed. Moreover, French National Chemical Library and ZINC database were also utilized to identify new structures different from fosfomycin. FlexX was the software used for this study. The antibacterial testing was divided into two methods: disk diffusion and broth dilution. RESULTS: A set of virtual hits was found to have better energy score than that of fosfomycin, seven of them were tested in vitro. In addition, the disk diffusion method explored four compounds that exhibited antibacterial activity: CID-21680357 (fosfomycin analogue), AB-00005001, ZINC04658565, and ZINC901335. The testing was continued by broth dilution method for both compounds CID-21680357 and ZINC901335 to determine their minimum inhibitory concentrations, and ZINC901335 had the best value with 457µg/ml against Staphylococcus aureus. CONCLUSION: Four compounds were found and proven in silico and in vitro to have antibacterial activity, namely CID-21680357, AB-00005001, ZINC04658565, and ZINC901335.

Assessment of antibacterial activity of levonadifloxacin against contemporary gram-positive clinical isolates collected from various Indian hospitals using disk-diffusion assay.

Objectives: Levonadifloxacin is a novel benzoquinolizine subclass of quinolone with broad-spectrum activities against problematic pathogens such as methicillin-resistant Staphylococcus aureus, quinolone-resistant S. aureus, vancomycin intermediate S. aureus, and vancomycin-resistant S. aureus. Levonadifloxacin and its oral prodrug, alalevonadifloxacin, have been recently approved in India for the treatment of acute bacterial skin and skin structure infections, including concurrent bacteraemia and diabetic foot infections. The aim of the study is to assess the activity of levonadifloxacin against Gram-positive clinical isolates collected from various Indian hospitals using the disc-diffusion method. Materials and Methods: Nonduplicate isolates of S. aureus and other Gram-positive isolates collected from June 2019 to March 2020 were subjected to levonadifloxacin susceptibility testing (disk diffusion method) as per the Clinical and Laboratory Standards Institute guidelines (Year 2019). Levonadifloxacin 10 µg impregnated disks were used during the testing. Results: A total of 664 diverse Gram-positive clinical isolates collected from six different hospitals in India were analyzed. Majority (65.5%) of the isolates were S. aureus. All the S. aureus and other Gram-positive isolates were found to be susceptible to levonadifloxacin as per the prespecified interpretive criteria identified based on population pharmacokinetic model and Monte Carlo simulation enabled probability of pharmacodynamic target attainment analysis. Conclusions: The present study showed that levonadifloxacin was highly active against contemporary Gram-positive pathogens and furthermore demonstrated that levonadifloxacin susceptibilities can be reliably determined using the disc-diffusion method.

Beta-lactams susceptibility testing of penicillin-resistant, ampicillin-susceptible Enterococcus faecalis isolates: a comparative assessment of Etest and disk diffusion methods against broth dilution.

This study aimed to evaluate the accuracy of disk diffusion and Etest methods, compared to that of the broth dilution reference method for identifying beta-lactam susceptibilities of Penicillin-Resistant, Ampicillin-Susceptible Enterococcus faecalis (PRASEF) isolates. Fifty-nine PRASEF and 15 Penicillin-Susceptible, Ampicillin-Susceptible E. faecalis (PSASEF) clinical nonrepetitive isolates were evaluated. The effectiveness of five beta-lactams (ampicillin, amoxicillin, imipenem, penicillin, and piperacillin) was tested. All antimicrobial susceptibility tests were performed and interpreted according to the Clinical and Laboratory Standards Institute guidelines. Interpretative discrepancies, such as essential agreement, categorical agreement, and errors, were assessed. The acceptability was ≥ 90% for both categorical agreement and essential agreement. Etest proved to be an accurate method for testing beta-lactam susceptibilities of the emerging PRASEF isolates, disk diffusion presented poor performance, particularly for imipenem and piperacillin.

Re-assessment of the disk diffusion technique for routine antimicrobial susceptibility testing for Helicobacter pylori.

BACKGROUND: The aim of this study was to assess the disk diffusion technique against E-test as a routine antibiotic susceptibility testing method for Helicobacter pylori. MATERIALS AND METHODS: Susceptibilities of 301 H pylori clinical isolates were simultaneously profiled by E-test and disk diffusion method for levofloxacin (5-µg disk), clarithromycin (15-µg disk), metronidazole (5-µg disk), amoxicillin (10-µg disk), and tetracycline (30-µg disk). Furazolidone susceptibility was evaluated using a 100-µg disk only. The correlation between MICs by E-test and inhibition zone diameters by disk diffusion was assessed by linear regression analysis. RESULTS: Correlation between inhibition zone diameters and MICs was found for levofloxacin (r = -.932), clarithromycin (r = -.894), and to a minor extent metronidazole (r = -.820). Using the linear regression analysis, the inhibition zone diameter breakpoints were calculated to be 29 mm for levofloxacin, 41 mm for clarithromycin, and 15 mm for metronidazole corresponding to the EUCAST-recommended MIC breakpoints. The susceptibility agreement between E-test and disk diffusion for levofloxacin, clarithromycin, and metronidazole was 98.6%, 96.0%, and 96.7%, respectively. The inhibition zone diameters recorded for the amoxicillin, tetracycline, and furazolidone were large (approximately 60 mm in mean), and a poor correlation was found between inhibition zone diameters and MICs for amoxicillin (r = -.594) and tetracycline (r = -.490). CONCLUSIONS: The disk diffusion can be used as a routine H pylori susceptibility testing method for levofloxacin, clarithromycin, and metronidazole in clinical practice under the described technical conditions. The use of disk diffusion for amoxicillin, tetracycline, and furazolidone susceptibility testing needs to be further studied.

Antibacterial efficiency assessment of polymer-nanoparticle composites using a high-throughput microfluidic platform.

Over the past decades, inorganic nanoparticles (NPs), particularly metal oxide NPs, have attracted great attention due to their strong bactericidal effects. Researchers have used NPs to fabricate nanocomposite materials which have innate antibacterial capability. Herein, we present a straightforward method to fabricate antibacterial nanocomposites. Ag, TiO2, and ZnO NPs were dispersed within liquid silicone rubber (LSR) structure in four concentrations. Three different methods were used to evaluate the antibacterial efficiency of the NPs forming the nanocomposite materials: (I) the diffusion method, (II) agar counting plate, and (III) a live/dead assay of E. coli. The mechanical properties and hydrophobicity of the nanocomposites were characterized and correlated to the antibacterial efficiency of the NPs. In order to test the antibacterial efficiency in a high-throughput, cost-effective and efficient manner, a microfluidic device fabricated by 3D printing and soft-lithography methods was used. The LSR-15 wt% TiO2 nanocomposites showed the best antibacterial efficiency. In addition, TiO2 NPs formed the stiffest nanocomposites with very fine, even surface which increased the hydrophobicity of the surface where bacteria attach to grow, preventing bacteria from further growth.

Biogenic synthesis and characterization of silver nanoparticles using aqueous leaf extract of Scoparia dulcis L. and assessment of their antimicrobial property.

Naturally occurring phytochemicals serve as an excellent substitute in synthesizing nanomaterials. A process for the synthesis of silver nanoparticles (AgNPs) from the aqueous leaf extract of naturally occurring Scoparia dulcis is described here. The extracellular formation of AgNPs occurred within few minutes upon incubation of S. dulcis aqueous leaf extract (0.1 mL) (100% extract) with silver nitrate (2 mM AgNO3) at 90 °C for 30 min, is first of its kind work. The appearance of bright yellow color with λmax 420 nm confirm the formation of AgNPs. Zeta potential and X-ray diffraction (XRD) studies reveal stable AgNPs (-22.7 mV) and characteristic spectra for silver. Fourier transform infrared (FTIR) spectroscopy indicate the involvement of carboxyl, amine and hydroxyl groups in the synthetic process. Transmission electron microscopy (TEM) show the spherical nature of AgNPs measuring 3-18 nm in size. Additional characterization using Dynamic light scattering (DLS) revealed the average particle size distribution of AgNPs as around 8.2 nm. Further antimicrobial testing through agar disc diffusion plate method indicated that silver nanoparticles are potentially active against pathogenic bacteria such as Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus aureus and are only optimally active against fungi such as Aspergillus niger and Candida albicans and measurement of minimal inhibition concentration by standard microdilution method. In conclusion, the study suggests that successful synthesis of green nanoparticles (AgNPs) using aqueous S. dulcis leaf extract is simple, rapid, environmentally benign and economical. Moreover, these synthesized silver nanoparticles showed antimicrobial activity.

In vitro assessment of antibacterial, antifungal, enzyme inhibition and hemolytic activities of various fractions of Rhynchosia pseudo-cajan.

The aims of the present investigation were to assess the antibacterial, antifungal, enzyme inhibition and hemolytic activities of various fractions of Rhynchosia pseudo-cajan Cambess. The methanolic extract of the plant was dissolved in the water (distilled) and then partitioned with the n-hexane, chloroform, EtOAc and n-BuOH sequentially. Antibacterial activity was checked against Escherichia coli, Pasturella multocida, Bacillus subtilis and Staphylococcus aureus by the disc diffusion method using streptomycin sulphate, a standard antibiotic, as positive control. Chloroform and ethyl acetate soluble fractions showed good activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. These fractions also showed good MIC values. The n-butanol soluble and remaining aqueous fraction also showed good activity against some strains. Antifungal activity was studied against four fungi i.e. Aspergillus niger, Aspergillus flavus, Ganoderma lucidum and Alternaria alternata by the disc diffusion method using fluconazole, a standard antifungal drug, as positive control. Chloroform, n-butanol and ethyl acetate soluble fraction showed good activity only against G. lucidum. Enzyme inhibition studies were done against four enzymes i.e. α-glucosidase, butyrylcholinesterase, acetyl cholinesterase and lipoxygenase. Aqueous fraction possessed very good activity against α-glucosidase, even greater than acarbose, a reference standard drug. Its IC50 value was found as 29.81±0.12 µg/ml as compared to acarbose having IC50 38.62±0.04 µg/ml. Chlroform and ethyl acetate soluble fractions also showed good activity against α-glucosidase. Ethyl acetate soluble and remaining aqueous fractions showed good activity against lipoxygenase. All the studied fractions showed very less toxicity i.e. <2.5%.

Green and cost effective synthesis of silver nanoparticles from endangered medicinal plant Withania coagulans and their potential biomedical properties.

Silver nanoparticles (AgNPs) have great potential for their mechanistic role in biomedical researches. Recently, green biosynthetic approaches have been received much attention in plant science for nanoparticles production. Therefore, in the present study AgNPs have been synthesized utilizing in-vitro grown leaf extract of anti-diabetic medicinal plant Withania coagulans Dunal by the reduction of silver nitrate solution. W. coagulans synthesized silver nanoparticles (WcAgNPs) were characterized by UV-visible spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, X-ray powder diffraction and Fourier transform Infra-Red spectroscopy. All cumulative results showed that WcAgNPs were ~14 nm in size having spherical shape with face centered cubic structure. High performance liquid chromatography confirmed the involvement of withanolides in AgNPs synthesis as a reducing/capping agent. Synthesized WcAgNPs showed greater antioxidative potential when compared with W. coagulans leaf extract. WcAgNPs have efficient antimicrobial potential and suppresses the growth of both gram positive and gram negative bacteria. In our finding we also observed cytotoxicity of WcAgNPs against SiHa (cervical cancerous, hyper-triploid) cell lines and apoptosis in SiHa cells after 48 hour incubation with 13.74 µg ml-1 (IC50) concentration of WcAgNPs. As results suggested, this is the first report which explain that W. coagulans leaf extract have potential as bio-reducing agent for synthesis of silver nanoparticles, which can be exploited as anti-oxidant, antimicrobial and anti-cancerous agent and depicting an effective way for utilizing bioactive resources in restoration of medicinal properties of this plant with high efficacy.

Ten years of external quality assessment (EQA) of Neisseria gonorrhoeae antimicrobial susceptibility testing in Europe elucidate high reliability of data.

BACKGROUND: Confidence in any diagnostic and antimicrobial susceptibility testing data is provided by appropriate and regular quality assurance (QA) procedures. In Europe, the European Gonococcal Antimicrobial Susceptibility Programme (Euro-GASP) has been monitoring the antimicrobial susceptibility in Neisseria gonorrhoeae since 2004. Euro-GASP includes an external quality assessment (EQA) scheme as an essential component for a quality-assured laboratory-based surveillance programme. Participation in the EQA scheme enables any problems with the performed antimicrobial susceptibility testing to be identified and addressed, feeds into the curricula of laboratory training organised by the Euro-GASP network, and assesses the capacity of individual laboratories to detect emerging new, rare and increasing antimicrobial resistance phenotypes. Participant performance in the Euro-GASP EQA scheme over a 10 year period (2007 to 2016, no EQA in 2013) was evaluated. METHODS: Antimicrobial susceptibility category and MIC results from the first 5 years (2007-2011) of the Euro-GASP EQA were compared with the latter 5 years (2012-2016). These time periods were selected to assess the impact of the 2012 European Union case definitions for the reporting of antimicrobial susceptibility. RESULTS: Antimicrobial susceptibility category agreement in each year was ≥91%. Discrepancies in susceptibility categories were generally because the MICs for EQA panel isolates were on or very close to the susceptibility or resistance breakpoints. A high proportion of isolates tested over the 10 years were within one (≥90%) or two (≥97%) MIC log2 dilutions of the modal MIC, respectively. The most common method used was Etest on GC agar base. There was a shift to using breakpoints published by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) in the latter 5 years, however overall impact on the validity of results was limited, as the percentage categorical agreement and MIC concordance changed very little between the two five-year periods. CONCLUSIONS: The high level of comparability of results in this EQA scheme indicates that high quality data are produced by the Euro-GASP participants and gives confidence in susceptibility and resistance data generated by laboratories performing decentralised testing.

Prospective evaluation of rapid antimicrobial susceptibility testing by disk diffusion on Mueller-Hinton rapid-SIR directly on blood cultures.

BACKGROUND: With the worldwide spread of antibiotic resistance, delivering antibiotic susceptibility test (AST) results in a timely manner represents a major challenge. In cases of sepsis, rapid AST may facilitate early optimization of empiric antibiotic therapy. Disc diffusion is a well-standardized AST method, however 16 to 24 h are required to achieve an overall AST profile according to antimicrobial societies. METHODS: In this prospective pilot study, we evaluated the performance of Mueller-Hinton-Rapid-SIR (MHR-SIR) agar after 6-8 h of incubation in comparison with standard MH agar after 16 h of incubation directly on positive blood cultures caused by Enterobacteriaceae and Staphylococcus aureus from routine clinical microbiology. A total of 133 positive blood samples including 110 Enterobacteriaceae (83%) and 23 Staphylococcus aureus (17%) were tested in parallel by two direct AST methods, each using EUCAST breakpoints. For each combination bacterium and antibiotic, we compared the categorical agreement and the correlation between the diameters obtained by MHR-SIR and by standard MH. RESULTS: Our results showed 97.7% categorical agreement for Enterobacteriaceae, with 1.4% minor errors, 0.4% major errors and 0.5% very major errors. For S. aureus, we observed 97.8% categorical agreement, 1.9% minor errors, 0.3% major errors and no very major errors. CONCLUSION: Our results showed excellent categorical agreement and correlations between diameters for MHR-SIR and standard MH methods. MHRSIR can predict the result of overall AST profile within 6-8 h with reliable results. AST is obtained on the same day the blood culture becomes positive, with a very moderate cost.

Performance characteristics of newer MIC gradient strip tests compared with the Etest for antimicrobial susceptibility testing of Neisseria gonorrhoeae.

For Neisseria gonorrhoeae susceptibility testing, Etest, comparable to agar dilution, is frequently used. In recent years, newer MIC gradient strip tests have been commercialized. However, these tests have not been appropriately evaluated for gonococci. We evaluated the sensitivity, specificity, accuracy, quality, availability of antimicrobials and cost of the MIC Test Strip (Liofilchem), M.I.C.Evaluator (Oxoid) and Ezy MIC Strip (HiMedia), compared to the reference Etest (bioMérieux), for gonococcal susceptibility testing. The MICs of eight antimicrobials in 103 gonococcal international reference strains (n = 29) and clinical isolates (n = 74) were examined. Coefficient of determination (R2 ), complete agreement, essential agreement, SIR categorical agreement, sensitivity, specificity and accuracy were calculated. R2 of the MICs for the antimicrobials ranged between 0.674-0.996, 0.617-0.993, and 0.643-0.994 for the MIC Test Strip, M.I.C.Evaluator strips and Ezy MIC Strips respectively. The essential agreement (SIR categorical agreement) was 99.6% (88.6%), 100% (87.1%) and 93.0% (83.1%) respectively. M.I.C.Evaluator strips for gonococcal key antimicrobials were lacking and the Ezy MIC Strips showed an inconsistent accuracy, quality and some strips were contaminated. The Liofilchem MIC Test Strips had limitations, but might be relatively accurate alternatives to Etest for gonococci. Strict quality assurance (at manufacturing and testing laboratory), including quality controls, are required.

Phyto-mediated synthesis of silver nanoparticles using fucoidan isolated from Spatoglossum asperum and assessment of antibacterial activities.

The present study was aimed to investigate the antibacterial efficacy of fucoidan mediated silver nanoparticles (Fu-AgNPs) synthesized from Spatoglossum asperum. The synthesized Fu-AgNPs were characterized by UV-visible, Field emission - scanning electron microscope (FE-SEM), Tranmission electron microscope (TEM), X-ray diffraction (XRD), Selected area electron diffraction (SAED) pattern, Energy-dispersive X-ray spectroscopy (EDAX), Fourier transform infrared spectroscopy (FT-IR), Dynamic light scattering (DLS) and Zeta potential analysis. The UV-visible spectrum of Fu-AgNPs exhibited a characteristic surface plasmon resonance (SPR) peak at 440 nm. The electron microscopic results revealed that the nanoparticles were spherical to oval in shape and are found to be 20 to 46 nm. Altogether the X-ray diffraction analysis showed that the Fu-AgNPs were crystalline in nature. The FT-IR spectrum confirmed the existence of CC stretching vibration of aromatic compounds and sulfated groups of fucoidan plays a major role in the synthesis of Fu-AgNPs. The biosynthesized Fu-AgNPs shows potential antibacterial activity against Klebsiella pneumoniae in agar bioassay, disk diffusion, reactive oxygen species, protein leakage and confocal laser scanning microscopy assays. Furthermore, Artemia toxicity assay results showed less mortality (3.3 ±â€¯0.8%) even at higher concentration of Fu-AgNPs. Therefore, Fu-AgNPs can be effectively used as an antibacterial agent in the pharmaceutical fields.

Assessment of 30/20-Microgram Disk Content versus MIC Results for Ceftazidime-Avibactam Tested against Enterobacteriaceae and Pseudomonas aeruginosa.

We evaluated the correlation between MIC and disk diffusion inhibition zones when testing ceftazidime-avibactam, using the 30/20-µg disk and the disk diffusion and MIC breakpoints established by the U.S. FDA and the Clinical and Laboratory Standards Institute (CLSI). Organisms used included 2 groups of Enterobacteriaceae isolates and 2 groups of Pseudomonas aeruginosa isolates; 1 group of each consisted of randomly selected isolates and the second group consisted of a challenge group from thousands of surveillance isolates with an increased proportion of organisms displaying ceftazidime-avibactam MIC values close to the breakpoints. Broth microdilution, disk diffusion tests, and data analysis were performed according to reference standardized methods. Ceftazidime-avibactam breakpoints of ≤8/4 (susceptible) and ≥16/4 µg/ml (resistant) for MIC and ≥21/≤20 mm for disk diffusion, as established by the U.S. FDA and the CLSI, were applied for Enterobacteriaceae and P. aeruginosa Ceftazidime-avibactam MIC and disk zone (30/20-µg disk) correlation were acceptable when testing Enterobacteriaceae (overall, very major [VM] and major [Ma] error rates of 0.4% and 0.0%, respectively) and nearly so when testing P. aeruginosa (2.3% VM and 2.9% Ma errors). In summary, disk diffusion and broth microdilution testing results demonstrated good categorical agreement for ceftazidime-avibactam against Enterobacteriaceae and P. aeruginosa, using 30/20-µg disks.

Broad bean (Vicia faba L.) pods: a rich source of bioactive ingredients with antimicrobial, antioxidant, enzyme inhibitory, anti-diabetic and health-promoting properties.

This study was aimed at investigating the chemical composition (proximate, minerals, fatty acids and phenolic compounds) and the in vitro (antimicrobial, radical scavenging, anti-acetylcholinesterase and protein denaturing activities) and in vivo (anti-diabetic and histo-protective effects in alloxan-induced diabetic mice) biological activities of broad bean pods (BBPs), a food waste by-product material. The results showed that BBPs have high dietary fiber (57.46%), carbohydrate (18.93%) and protein (13.81%) content versus low fat content (<1%) contributing to a low energy value of 139.24 kcal per 100 g. Profiling of fatty acids showed an abundance of the essential polyunsaturated α-linolenic and linoleic acids, exhibiting an excellent nutritional quality as revealed by their low atherogenic and thrombogenic indices and their hypocholesterolemic properties. The methanol extract which exhibited the highest total phenolic, flavonoid and tannin contents was found to be the most active extract in terms of antimicrobial and anti-radical activities. In alloxan-induced diabetic mice, the oral administration of a methanol extract (500 mg per kg bw) attenuated the elevated levels of serum alanine aminotransferase (ALA), aspartate aminotransferase (AST), and alkaline phosphatase activities, and urea, uric acid, and creatinine. It effectively normalized the status of lipid profiles, mitigated oxidative stress through the activation of antioxidant enzymes (CAT, GPx and SOD), and alleviated oxidative stress-mediated histopathological changes in the pancreas, liver, kidney and testis. Compositional analysis by HPLC-PDA-ESI-MS/MS revealed the presence of flavan-3-ols (catechin, epicatechin and their derivatives), flavones (apigenin derivatives) and flavonols (glycosides of quercetin and kaempferol), among others. These findings suggest that BBPs may be an effective functional food for the management of diabetes and its complications.

Antibacterial Susceptibilities of Escherichia coli from Community-Acquired Urinary Tract Infections in the Faroe Islands, Associations with Antibacterial Sales, and Comparison with Iceland and Denmark.

Currently, data on Escherichia coli antibacterial susceptibilities in the Faroe Islands are lacking. The aim was to investigate the antibacterial susceptibilities of E. coli from patients with community-acquired urinary tract infections in the Faroe Islands, correlate with antibacterial sales, and compare with Iceland and Denmark. From 2009 to 2010 and in 2012, 12 general practitioners from the Faroe Islands were recruited to provide urine samples from patients. Antibacterial susceptibilities were determined by disc diffusion testing according to the Clinical and Laboratory Standards Institute methods and criteria. Logistic regression (quasibinomial) of the antibacterial resistance proportions versus mean sales during the period of 2008-2011 was used to determine association. Nonsusceptibility to at least 1 of the 14 antibacterial drugs investigated was found in 54% of the E. coli isolates and was most common to ampicillin (46%), followed by sulfamethoxazole (39%), trimethoprim (27%), trimethoprim/sulfamethoxazole (27%), and <10% to the remaining 10 antibiotics. The resistance prevalence did not change significantly with time. From logistic regression modeling, we find significant associations between antibacterial mean sales and antibacterial resistances. For the resistances in the Faroe Islands compared with data from Denmark and Iceland, we infer two groups of resistances indicating different responses-one steep and one gradual-to antibacterial sales. For these two groups, we find ß1 = 4.77 (Std. Error = 0.624, p-value = 0.002) and ß1 = 0.26 (Std. Error = 0.020, p-value = 4e-7) for the steep and gradual groups, respectively. This knowledge can potentially be used to predict and control the future increase in E. coli resistance with antibacterial sales.

A cost-saving strategy for processing isolated uropathogens in community-acquired urinary tract infections.

Outpatient urine samples are among the most commonly processed in a microbiology laboratory, which involves a high economic burden. The aim of this study was compare cost and efficiency to process uropathogens between MicroScan system (2010-2011) versus a chromogenic medium and the disk diffusion method (2013-2014). In the first period, a total 9918 bacterial populations were isolated from urine samples. Annual estimated costs during 2010 and 2011 for processing were EUR 53,818 and EUR 57,306, respectively (EUR 111,124 total). In the second period, a total 11,728 bacterial isolates were processed, with annual estimated costs of EUR 21,078 and EUR 23,248, respectively (EUR 44,326 total). We included the cost for a laboratory technician (252h worked per year), estimated at EUR 2500 per year. The mean estimated savings were EUR 66,797 (60%).The identification by chromogenic media and antibiotic susceptibility patterns by disk diffusion method was similar to MicroScan in both study periods. Only some isolated Citrobacter spp., Enterobacter spp., Morganella morganii, and Providencia spp. were misidentified. The strategy reported here did not affect the quality of the results and yielded substantial cost savings.

A new rapid resazurin-based microdilution assay for antimicrobial susceptibility testing of Neisseria gonorrhoeae.

Objectives: Rapid, cost-effective and objective methods for antimicrobial susceptibility testing of Neisseria gonorrhoeae would greatly enhance surveillance of antimicrobial resistance. Etest, disc diffusion and agar dilution methods are subjective, mostly laborious for large-scale testing and take ∼24 h. We aimed to develop a rapid broth microdilution assay using resazurin (blue), which is converted into resorufin (pink fluorescence) in the presence of viable bacteria. Methods: The resazurin-based broth microdilution assay was established using 132 N. gonorrhoeae strains and the antimicrobials ceftriaxone, cefixime, azithromycin, spectinomycin, ciprofloxacin, tetracycline and penicillin. A regression model was used to estimate the MICs. Assay results were obtained in ∼7.5 h. Results: The EC 50 of the dose-response curves correlated well with Etest MIC values (Pearson's r = 0.93). Minor errors resulting from misclassifications of intermediate strains were found for 9% of the samples. Major errors (susceptible strains misclassified as resistant) occurred for ceftriaxone (4.6%), cefixime (3.3%), azithromycin (0.6%) and tetracycline (0.2%). Only one very major error was found (a ceftriaxone-resistant strain misclassified as susceptible). Overall the sensitivity of the assay was 97.1% (95% CI 95.2-98.4) and the specificity 78.5% (95% CI 74.5-82.9). Conclusions: A rapid, objective, high-throughput, quantitative and cost-effective broth microdilution assay was established for gonococci. For use in routine diagnostics without confirmatory testing, the specificity might remain suboptimal for ceftriaxone and cefixime. However, the assay is an effective low-cost method to evaluate novel antimicrobials and for high-throughput screening, and expands the currently available methodologies for surveillance of antimicrobial resistance in gonococci.