Standard Disk Diffusion Method Research Articles

Gene profile of virulence, antimicrobial resistance and action of enterocins in Campylobacter species isolated from broiler carcasses.

Campylobacteriosis is among the most reported zoonoses in the world, caused by species of Campylobacter, this disease is characterized by gastroenteritis in humans. The main species involved is Campylobacter jejuni, followed by Campylobacter coli. Contaminated chicken meat is often identified as an important source of infection related to human cases and Brazil is the largest exporter of chicken meat in the world, which makes the characterization of brazilian isolates crucial for the establishment of control measures. The objective was to evaluate the contamination of chilled and frozen carcasses sold in the Northeast of Brazil, by Campylobacter species, identify virulence genes, evaluate bacterial resistance to antibiotics and verify the antimicrobial action of the Crude Extract Containing Enterocins (CECE) produced by a probiotic strain of Enterococcus faecium. In this study, 12 chilled carcasses and 12 frozen carcasses were collected, sold retail in supermarkets. The following regions of the carcass were sampled: breast skin, wing skin, belly skin, neck skin, gizzard and liver. Samples of chicken carcasses were analyzed following ISO 10272-2 guidelines for the isolation of Campylobacter spp. The isolates were tested by PCR to identify genus, species C. jejuni, C. coli and C. lari and genes cdtA, cdtB, cdtC, sodB, dnaJ, cmeA, cmeB, cmeC. The assessment of susceptibility to antibiotics was carried out using the standard disk diffusion method and the antimicrobial activity of CECE was determined using the Minimum Inhibitory Concentration (MIC), the methodologies followed the recommendations and cutoff points according to EUCAST and CLSI. A total of 376 isolates of Campylobacter spp. were obtained, among these, 26 (7.0%) were positive for C. jejuni and no isolates were detected for C. coli and C. lari. The highest frequency of C. jejuni was obtained in chilled carcasses with 23 isolates (88.5%, p < 0.0001), in frozen carcasses three isolates were obtained (11.5%). The most frequency site of C. jejuni was the chest skin (7/27.0%), followed by skin of the wing (6/23.0%), skin of the cloaca (5/19.0%), gizzard (4/15.0%), skin of the neck (2/8.0%) and liver (2/8.0%), no significant differences were found between the sites sampled. The gene frequency was determined in: cdtA (3/11.5%), cdtB (3/11.5%), cdtC (5/19.0%), sodB (9/34.5%), dnaJ (3/11.5%), cmeA (4/15.0%), cmeB (4/15.0%) and cmeC (4/15.0%). The three efflux pump genes were amplified in four isolates (15.3%) and all tested genes were amplified in three isolates (11.5%). All C. jejuni isolates (26/100.0%) were found to be multiresistant to three or more classes of antimicrobials. The index of multiple resistance to antimicrobial drugs (IRMA) ranged from 0.4 to 1.0 among isolates of C. jejuni. The antimicrobial activity of CECE was able to inhibit at least 98.5% of the growth of all C. jejuni isolates. Therefore, chilled chicken carcasses present a greater risk of contamination than frozen carcasses, for this reason it is necessary to adopt practices that avoid cross-contamination during the preparation of chicken meat, in order to prevent campylobacteriosis. Furthermore, the presence of multiresistant and potentially virulent isolates highlights the need for further investigations to better understand the use of enterocins as alternative methods in the control of Campylobacter.

Impact of Fe3+ and Al3+ co-doping on the structure, optical properties, and antibacterial activities of ZnO nanoparticles

Understanding the potential role of nanoparticles (NPs) in the global antibiotic resistance threat is essential. This study focuses on the potential antibacterial applications of Zn1−2x(Fe, Al)xO (x = 0.0, 0.02, 0.035, 0.05, and 0.065) NPs synthesized using the citrate–nitrate solution combustion method. The synthesized NPs were characterized using XRD, FESEM, FTIR, UV–Vis, and PL spectroscopies. Their antibacterial performance was assessed using the standard disc diffusion method. The synthesized NPs exhibited a single-phase hexagonal wurtzite structure (P63mc space group), with crystallite sizes ranging from 8.5 to 19.74 nm, which decreased with increasing dopant concentration. Incorporation of Fe3+ and Al3+ significantly altered key parameters of ZnO NPs, including lattice constant, bond length, dislocation density, and microstrain. Furthermore, FESEM revealed the formation of relatively spherical grains with sizes ranging from 28.42 to 56.54 nm. FTIR confirmed the presence of metal–oxygen bonds, and changes in optical properties of ZnO NPs were observed in the UV and PL spectra due to the dopants. The direct optical band gap energies ranged from 3.29 eV to 3.43 eV, indicating a notable effect of doping. Incorporating Fe3+ and Al3+ into Zn1−2x(Fe, Al)xO led to a substantial enhancement in antibacterial efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), increasing the zones of inhibition (ZOI) (at a concentration of 33.33 mg/mL) from 14.14 mm to 16.14 mm and from 17.14 mm to 19.18 mm, respectively. Among all samples, Zn0.96Fe0.02Al0.02O NPs exhibited outstanding antibacterial activity, with ZOIs of 16.14 mm and 19.18 mm against S. aureus and E. coli, respectively. This study also suggests enhanced antibacterial mechanisms for the Zn0.96Fe0.02Al0.02O NPs.

In-vitro and In-silico evaluation of antimicrobial and antibiofilm effect of Neem oil and Calcium hydroxide nanoparticles against Mutans Streptococci and Enterococcus faecalis isolated from endodontic infections

Different Streptococcal species including Streptococcus mutans, Streptococcus sobrinus and Enterococcus faecalis are commonly isolated in root canal infections including refractory, recurrent, and persistent cases. Calcium hydroxide (Ca (OH)2) has been widely used in endodontics as an intracanal medicament. However, using new antimicrobial herbal alternatives offers promising potentials which can be additionally enhanced by using nanoparticles (NPs). In this study, we evaluate the antimicrobial efficacy and antibiofilm effect of Neem oil including its NPs preparations and we compare the effect of conventional Ca (OH)2 to Ca (OH)2 NPs using standard disc diffusion method and quantitative microtitre dish biofilm formation assay against common pathogens isolated from root canal samples. Molecular docking was used to test the binding of 10 Streptococcal macromolecules to 5 candidate neem active constituents. Neem NPs 0.125 mg/ml showed better antibacterial effect than both Neem 15 mg/ml and Neem 0.15 mg/ml. Ca (OH)2 NPs 0.125 mg/ml also showed better antibacterial effect than each of Ca (OH)2 10 mg/ml and Ca (OH)2 0.1 mg/ml. Best biofilm mass inhibition was achieved by Neem oil 0.15 mg/ml at 74.55% ( IQ: 67.36–87.65) and Neem NPs 0.0125 mg/ml at 59.33% (IQ: 51-–75.27). For Ca (OH)2, the best biofilm mass inhibition was observed with Ca (OH)2 NPs 0.125 mg/ml at 54.7% (IQ: 42.37– 77.25). Both neem oil and neem NPs show promising antibacterial and antibiofilm potential against Mutans Streptococci group at low concentrations and hence are good candidates for use as endodontic medications. In silico analysis shows that both Sitosterol and Gedunin appear to be important active constituents of neem and possible drug candidates. Additionally, Ca (OH)2 NPs showed significantly higher antimicrobial effect against Mutans streptococci group than conventional Ca (OH)2 preparations.

Isolation and Pattern of Antimicrobial Susceptibility Testing of Acinetobacter baumannii Clinical Isolates at Taksin Hospital: A Retrospective Study from 2019 to 2021

Objective: To determine the number of isolates and drug susceptibility testing of Acinetobacter baumannii at Taksin Hospital. Materials and Methods: A 3-year retrospective descriptive study was conducted between January 2019 and December 2021. Drug susceptibility testing of isolates to 13 drugs, which included amikacin, gentamycin, piperacillin/tazobactam, cefotaxime, ceftazidime, cefepime, three carbapenem drugs that were imipenem, meropenem, and doripenem, ciprofloxacin, trimethoprim-sulfamethoxazole, colistin, and tigecycline, were evaluated by standard disk diffusion method and automated microdilution method. Results: One thousand six hundred sixty-five non-duplicate A. baumannii isolates from different patients were detected and included 535 in 2019, 500 in 2020, and 630 in 2021. The patients’ ages ranged from three days to 100 years. The median age of patients was 70 years with an interquartile range of 56 to 80 years. A. baumannii was mostly found in patients aged older than 50 years old at 83.6%. They were isolated from sputum in 72.3%, urine in 9%, pus in 6.3%, tissue in 6.3%, and blood in 5.2%. Overall, A. baumannii demonstrated 91.5% and 79.8% susceptibility to colistin and tigecycline, respectively, but less susceptible to other drugs tested, with a range of 0.4% to 32.6%. Drug susceptibility to carbapenem such as imipenem, meropenem, and doripenem were 19.5%, 20%, and 20.9%, respectively. The carbapenem-resistant A. baumannii (CRAB) was found at 77.6%, 80%, and 79.1% in 2019, 2020, and 2021, respectively. For total isolates tested, the mean of CRAB was 78.9±1.2%. Conclusion: The present study results suggested the importance of monitoring A. baumannii at a hospital in Bangkok. Colistin and tigecycline had the high percentages of drug susceptibility rates in vitro. The antibiogram of susceptibility helps provide guidelines for clinician to consider empirical treatment.

Bactericidal and Synergistic Effects of Lippia origanoides Essential Oil and Its Main Constituents against Multidrug-Resistant Strains of Acinetobacter baumannii.

Bacterial resistance in Acinetobacter baumannii is a significant public health challenge, as these bacteria can evade multiple antibiotics, leading to difficult-to-treat infections with high mortality rates. As part of the search for alternatives, essential oils from medicinal plants have shown promising antibacterial potential due to their diverse chemical constituents. This study evaluated the antibacterial, antibiofilm, and synergistic activities of the essential oil of Lippia origanoides (EOLo) and its main constituents against multidrug-resistant clinical isolates of A. baumannii. Additionally, the antibacterial and antibiofilm potential of a nanoemulsion containing carvacrol (NE-CAR) was assessed. EOLo was extracted through hydrodistillation, and its components were identified via gas chromatography coupled with mass spectrometry. The A. baumannii isolates (n = 9) were identified and tested for antimicrobial susceptibility using standard disk diffusion methods. Antibacterial activity was determined by broth microdilution, while antibiofilm activity was measured using colorimetric methods with crystal violet and scanning electron microscopy. Synergism tests with antibiotics (meropenem, ciprofloxacin, gentamicin, and ampicillin+sulbactam) were performed using the checkerboard method. The primary constituents of EOLo included carvacrol (48.44%), p-cymene (14.58%), and thymol (10.16%). EOLo, carvacrol, and thymol demonstrated significant antibacterial activity, with carvacrol showing the strongest effect. They were also effective in reducing biofilm formation, as was NE-CAR. The combinations with antibiotics revealed significant synergistic effects, lowering the minimum inhibitory concentration of the tested antibiotics. Therefore, this study confirms the notable antibacterial activity of the essential oil of L. origanoides and its constituents, especially carvacrol, suggesting its potential as a therapeutic alternative for A. baumannii infections.

Association between the presence of CRISPR-Cas system genes and antibiotic resistance in Klebsiella pneumoniae isolated from patients admitted in Ahvaz teaching hospitals

BackgroundThis study aims to investigate the frequency of cas1 and cas3 and CRISPR1,2,3 genes in Klebsiella pneumoniae isolates, as well as their connection with antibiotic resistance.Materials and methods106 K. pneumoniae isolates were identified by biochemical assays and PCR. The susceptibility to antibiotics was determined by Kirby–Bauer disk diffusion method. Screening of ESBLs was undertaken by using double disk diffusion and standard disk diffusion methods. The E-test and mCIM techniques was used to confirm the disc diffusion-based carbapenem resistance profiles. CRISPR-Cas system genes were identified using PCR.ResultsESBL production was found in 19% of isolates. Carbapenemase production was found in 46% of the isolates. Furthermore, the bacteria were classified as multidrug (76%), extensively drug-resistant (4%), or pan-drug-resistant (2%). When CRISPR/Cas systems were present, antibiotic resistance was lower; conversely, when they were absent, resistance was higher.ConclusionsIf the CRISPR/Cas modules aren’t present, the bacteria can still acquire foreign DNA, including antibiotic resistance genes. K. pneumoniae isolates with a CRISPR-Cas system were less likely to carry antibiotic-resistance genes than those lacking this defense system.

Особливості протимікробної дії препаратів полігексаніду до домінуючих збудників ранової інфекції в Україні: сучасні реалії

The treatment of acute and chronic wounds with critical colonization by wound pathogens remains a serious problem, which is becoming more and more threatening every year due to the global problem of antibiotic resistance. Aim - to study the antimicrobial activity of modern antiseptic Polyhexanide and antimicrobial biomaterials based on it against most common pathogens of wound infections. Materials and methods. Antimicrobial activity of polyhexanide solution were studied against MLS -resistant clinical isolates of S. aureus, MDR- strains of E. coli, clinical XDR-isolates of K. pneumoniae, P. aeruginosa, and A. baumannii as well as referent strains S. aureus ATCC 25923, E. coli ATCC 25922, K. pneumoniae ATCC 708603, P. aeruginosa ATCC 27853, A. baumannii ATCC ВАА-747. MIC and MBC of polyhexanide were detected by standard dilution method; bactericidal index of antiseptic activity (BC IAA) for 0.1% polyhexamethylen-biguanide solution for wound irrigation (PHMB) was calculated. The bioactivity of wound antimicrobial dressings with polyhexamethylenguanidyn-hydrochoridi (PHMB-HCl) and PHMB was determined by standard disk diffusion method; growth inhibition zones (GIZ) were measured and compared. Results. MLS-resistant strains of S. aureus were the most susceptible to the action of the antiseptic: the MIC and MBC of PHMB were on average 22.69±4.6 μg/ml and 40.55±8.57 μg/ml, respectively. The MIC values against S. aureus was lower than those against E. coli by 1.97 times, against K. pneumoniae – by 1.78 times, against A. baumannii – by 2.97, against P. aeruginosa – 3.9 times. The MBC of PHMB against clinical strains of S. aureus had the lowest values and differed significantly from those against E. coli by 2.21 times, K. pneumoniae by 1.99 times, A. baumannii by 3.4 times, P. aeruginosa by 4.52 times. The bactericidal index of antiseptic activity (BC IAA) of PHMB had the highest values in relation to clinical strains of S. aureus (BC IAA=24.7), K. pneumoniae (BC IAA=12.4) and E. coli (BC IAA=11.2). Wound dressings PHMB-HCl and PHMB demonstrated high antimicrobial properties against reference and clinical strains of S. aureus, E. coli, K. pneumoniae. Reference and clinical strains of P. aeruginosa were the least susceptible to PHMB-based wound dressings. Conclusions. Polyhexanide antiseptic solution for wound irrigation and polyhexanide-containing dressings with PHMB and PHMB-HCl have the high antimicrobial properties in relation to the most common types of wound pathogens. No conflict of interests was declared by the authors.

A comparative study of a rapid phenotypic antimicrobial susceptibility testing system directly from positive blood cultures to the disk diffusion and VITEK 2 methods

BackgroundSepsis is a life-threatening condition that impacts 49 million people annually and causes 11 million deaths worldwide. Surviving bloodstream infections (BSIs) depends on the rapid administration of effective antimicrobial treatment, underscoring a need for rapid antimicrobial susceptibility testing (AST). AimTo evaluate the performance of Quantamatrix's dRAST v2.5 system (Seoul, South Korea) for AST directly from positive blood cultures as compared to the Disk-Diffusion (DD) and VITEK 2 methods. MethodsThe study included 191 positive blood cultures from clinical samples and spiked blood culture bottles. Following Gram staining and species-level identification, AST was performed by VITEK 2 and standard DD methods using CLSI (2021) interpretation. ResultsdRAST demonstrated very good AST performance for a Gram-negative isolate, and good performance for Gram-positive isolates, meeting CLSI criteria for the acceptance of a new method. Antimicrobials that were not considered verified compared to VITEK 2 and DD were cefazolin, ceftazidime, meropenem, and trimethoprim/sulfamethoxazole for Gram-negatives and clindamycin, erythromycin, penicillin, and oxacillin for Gram-positives. dRAST ESBL detection results were strongly correlated with the ESBL phenotypes obtained with other methods. Additional resistance mechanisms were in concordance with traditional tests. ConclusionsdRAST demonstrated good AST performance, meeting CLSI criteria for most relevant antibiotics. dRAST was associated with a significant reduction in time-to-results, labor, and the subjectivity of result analyses, making it a valuable addition to efforts supporting the treatment of patients with bacteremia.AST (antimicrobial susceptibility test), blood culture, dRAST, rapid methods, sepsis, turnaround time (TAT).

Evaluating EUCAST rapid antimicrobial susceptibility test from positive neonatal blood culture directly against the golden standard disc diffusion method in a tertiary hospital

Evaluating EUCAST rapid antimicrobial susceptibility test from positive neonatal blood culture directly against the golden standard disc diffusion method in a tertiary hospital

Antibiotic profile classification of Proteus mirabilis using machine learning: An investigation into multidimensional radiomics features

Antimicrobial resistance (AMR) presents a significant threat to global healthcare. Proteus mirabilis causes catheter-associated urinary tract infections (CAUTIs) and exhibits increased antibiotic resistance. Traditional diagnostics still rely on culture-based approaches, which remain time-consuming. Here, we study the use of machine learning (ML) to classify bacterial resistance profiles using straightforward microscopic imaging of P. mirabilis for resistance classification integrated with radiomics feature analysis and ML models.From 150 P. mirabilis strains isolated from catheters of patients diagnosed with a CAUTI, 30 % displayed multidrug resistance using the standardized disk diffusion method, and 60 % showed strong biofilm activity in microtiter plate assays. As a more rapid alternative, we introduce wavelet-based and regular microscopy imaging with feature extraction/selection, following image preprocessing steps (image denoising, normalization, and mask creation). These features enable training and testing different ML models with 5-fold cross-validation for P. mirabilis resistance classification. From these models, the Random Forest (RF) algorithm exhibited the highest performance with ACC = 0.95, specificity = 0.97, sensitivity = 0.88, and AUC = 0.98 among the other ML algorithms considered in this study for P. mirabilis resistance classification.This successful application of wavelet-based feature Radiomics analysis with RF model represents a crucial step towards a precise, rapid, and cost-effective method to distinguish antibiotic resistant P. mirabilis strains.

Solid waste dumpsite leachate and contiguous surface water contain multidrug-resistant ESBL-producing Escherichia coli carrying Extended Spectrum β-Lactamase (ESBL) genes

Dumpsites generate leachates containing bacteria that may carry antibiotic resistance genes, such as extended spectrum β-lactamase (ESBL). However, the contribution of dumpsite leachates in the environmental spread of ESBL genes has not been investigated in greater detail. This study aimed to quantify the impact of Ajakanga dumpsite leachate on the spread of ESBL genes through surface water. The susceptibility of Escherichia coli isolated from dumpsite leachate and the accompanying surface water to selected antibiotics was assessed by the standardized disc diffusion method. The isolates were evaluated for phenotypic ESBL production using the double disc synergy test (DDST). The detection of ESBL genes in the isolates was carried out using a primer-specific polymerase chain reaction (PCR). Escherichia coli isolates from leachate (n = 26/32) and surface water (n = 9/12) expressed ESBL phenotype. The ESBL-producing isolates showed the highest level of resistance to the 3rd generation cephalosporin antibiotics: cefotaxime (100%), cefpodoxime (97%), ceftazidime (97%), with low resistance observed to imipenem (6%) and azithromycin (3%). All the isolates were multidrug-resistant, showing resistance to three or more classes of antibiotics. All the ESBL-producing E. coli obtained carried blaCTX−M, 21/35 (60%) carried blaTEM while none of the isolates bore blaSHV. This study found that ESBL-producing Escherichia coli from dumpsite leachate and nearby surface water had identical resistance signatures indicating the relatedness of the isolates, and that dumpsite leachate could contribute to the transfer of ESBL-producing bacteria and their genes to receiving surface water. This study has necessitated the need for a review of the guidelines and operational procedures of dumpsites to forestall a potential public health challenge.

Synthesis of Zn0.87(Fe, Al)0.065O – MO (MO = NiO, Fe2O3, CuO, and CoO) nanocomposites: Structural, vibrational, optical and antibacterial studies

One of the most effective strategies for achieving high-performance antibacterial activity is the synthesis of nanocomposites by combining different nanoparticles. Hence, Zn0.87(Fe, Al)0.065O – MO (NiO, Fe2O3, CuO and CoO) nanocomposites (NCs) with a 7:3 molar ratio were synthesized via the solution combustion method. The produced NCs structural, vibrational, and optical characteristics were investigated using XRD, FTIR, UV–Vis, and PL spectroscopies. The standard disc diffusion method was used to evaluate the antibacterial efficacy of the NCs. The lattice constant, crystallite size, bond length, dislocation density, and other relevant parameters of the NCs were also evaluated. XRD analysis revealed a well-defined mixed-phase structure for all 0.7Zn0.87(Fe, Al)0.065O – 0.3NiO (ZFA-Ni), 0.7Zn0.87(Fe, Al)0.065O – 0.3Fe2O3 (ZFA-Fe), 0.7Zn0.87(Fe, Al)0.065O – 0.3CuO (ZFA-Cu) and 0.7Zn0.87(Fe, Al)0.065O – 0.3CoO (ZFA-Co) NCs, indicating successful mixing of each metal oxide with the ZnO matrix. The average crystallite size within the NCs ranged from 14.21 to 18.10 nm, suggesting a degree of nanocrystallinity nature of all NCs. FTIR confirmed the presence of characteristic functional groups within the NCs. Moreover, all the synthesized NCs exhibited significant optical activation in the ultraviolet radiation range but visible light absorption was also observed when the composite formed with CuO and Fe2O3 nanoparticles. The band gap energy values exhibited variation between 2.72 eV for ZFA-Co NC and 2.90 eV for ZFA-Ni NC. Photoluminescence (PL) emission in the composite formation of ZnO NPs with other metal oxide were significantly influenced by the absorption range of the composite with pn-junction formation in a notable enhancement of antibacterial efficacy against bacterial strains of Escherichia coli and Staphylococcus aureus. Particularly, ZFA-Co NC exhibited an excellent antibacterial performance against both bacterial strains.

Detection of Typhoid Fever by Immuno Chromatographic Test (ICT) and Antibiotic Susceptibility Pattern of Salmonella Typhi in Chittagong Metropoliton City

Typhoid fever caused by the Salmonella typhi is a disease of global distribution and one of the major health problems in many developing countries. In this study, clinically suspected thirty five patients were enrolled from different diagnostic centers of Chittagong city. We evaluated the reliability of Immuno Chromatographic Test (ICT) compared to different diagnostic methods like blood/serum culture and serological/Widal test for early detection of the disease. A total of 18 (51.43%) and 20 (57.14%) samples were found positive in culture method and Widal test, respectively, whereas 31 (88.57%) were found positive in ICT. Moreover, 13 culture negative and 11 Widal test negative samples were found positive in ICT. As the ICT showed satisfactory results compared to the other methods used in this survey, it can be considered as a reliable method for the early detection of typhoid infection. The study revealed several antibiotic resistant patterns by standard disc diffusion method, 12 (66.66%) out of 18 culture positives were found multi-drug resistant. The Chittagong Univ. J. B. Sci.,Vol. 10(1 &amp;2):53-70, 2020

Antibacterial Properties of Mint Nanoemulsion Against Uropathogenic Escherichia coli Carrying Beta-Lactamase Resistance Genes

Background: Uropathogenic Escherichia coli (UPEC) is a significant contributor to urinary tract infections (UTIs). The inappropriate prescription and utilization of antibiotics in treating UTIs have resulted in a rise in antibiotic resistance. The aim of this study was to investigate the antibacterial properties of mint nanoemulsion against beta-lactam-resistant strains of UPEC. Methods: Three hundred fifty urine samples were collected in sterile containers and cultured on eosin-methylene blue agar and blood agar media under sterile conditions. Microbial sensitivity testing was conducted using the standard disk diffusion method. Molecular analysis was performed to identify the blaTEM, blaSHV, and blaCTX genes in the samples. The mint nanoemulsion was produced using the low-energy method of spontaneous emulsion formation and characterized using scanning electron microscopy (SEM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR). The antibacterial activity of the mint nanoemulsion against multidrug-resistant (MDR) isolates underwent assessment. Results: One hundred UPEC strains were isolated and identified, showing differing levels of resistance and sensitivity to various antibiotics. Nitrofurantoin exhibited the highest resistance (22%), while amikacin had the lowest resistance (4%). The prevalence of the blaTEM, blaSHV, and blaCTX genes among the UPEC isolates was 93.33%, 100%, and 73.33%, respectively. The mint nanoemulsion demonstrated effective antibacterial activity against resistant isolates, with a minimum inhibitory concentration of 0.2 mg/µL and a minimum bactericidal concentration of 0.3 mg/µL. Conclusion: The resistance of UPEC against conventional antibiotics commonly used to treat UTIs was consistently high and demonstrated an increasing trend over time. This escalating situation could potentially become more severe in the future if the rational consumption of antibiotics is not carefully managed. Nanoemulsions synthesized using mint revealed promising stability and robust antimicrobial properties against UPEC isolates. Consequently, it is evident that these synthesized nanoemulsions represent a viable candidate as effective antimicrobial agents in combating antibiotic resistance in UTI treatment.

Colistin-resistance genes in Escherichia coli isolated from patients with urinary tract infections.

The incidence of antimicrobial resistance is alarmingly high because it occurs in humans, environment, and animal sectors from a "One Health" viewpoint. The emergence of plasmid-carried mobile colistin-resistance (MCR) genes limits the efficacy of colistin, which is the last-line treatment for multidrug resistance (MDR) against gram-negative infections. The current study aimed to investigate emergence of colistin-resistance (MCR 1-5) genes in E. coli isolated from patients with urinary tract infections (UTIs) in Jordan. E. coli (n = 132) were collected from urine specimens. The E. coli isolated from human UTI patients were examined the resistance to colistin based on the presence of MCR (1-5). All isolates were tested against 20 antimicrobials using the standard disk diffusion method. The broth microdilution technique was used to analyze colistin resistance. In addition, the MCR (1-5) genes were detected using multiplex PCR. Out of the 132 isolates, 1 isolate was colistin-resistant, having a minimum inhibitory concentration of 8 μg/mL and possessing MCR-1. All the E. coli isolates showed high resistance to penicillin (100%), amoxicillin (79.55%), cephalexin (75.76%), nalidixic acid (62.88%), tetracycline (58.33%), or cefepime (53.79). To our knowledge, this is the first report on the presence of plasmid-coded MCR-1 in E. coli from a patient with UTIs in Jordan. This is a problematic finding because colistin is the last-line drug for the treatment of infections caused by MDR gram-negative bacteria. There is a crucial need to robustly utilize antibiotics to control and prevent the emergence and prevalence of colistin-resistance genes.

Antifungal Susceptibility Pattern of Fungi Isolated from Patients with Otomycosis Attending a Tertiary Health Care Institution in Sokoto, Nigeria

Abstract Background: Antifungal therapy is an important component of patient management for acute and chronic mycoses. However, treatment choices are restricted because of the scanty number of antifungal drug classes. Medical treatment of otomycosis is further compromised by the emergence of antifungal drug resistance, and these limits available drug classes as treatment options. Once considered a rare occurrence, antifungal drug resistance is on the rise in many high-risk medical centers. Most concerning is the evolution of multidrug-resistant organisms refractory to several different classes of antifungal agents, especially among common Candida species. Aim: This study seeks to identify the fungal species implicated in otomycosis among patients attending a tertiary health-care institution in Sokoto, Nigeria and determine its susceptibility pattern using commonly used antifungal agents. Methods: A descriptive, cross-sectional, hospital-based study was conducted on 100 patients with otitis externa. The ear discharge specimens were collected and analyzed using the standard microbial techniques. The antibiotic susceptibility profiles were determined for 12 different antifungal by the standard disk diffusion method. Data were analyzed using the SPSS software version 25 and the P &lt; 0.05 was considered as statistically significant. Results: One hundred and twenty-four external ear discharge samples were collected from either right ear, left ear, or both ears (some patients has unilateral while others have bilateral disease and those with bilateral disease, samples were taken from the two ears). Aspergillus niger 30 (40.0%) was the most commonly isolated fungi in this study, followed by Candida spp. 25 (33.3%), Aspergillus fumigatus 5 (6.7%), Mucor 5 (6.7%), Penicillum 4 (5.3%), Aspergillus flavus 3 (4.0%), and Rhizopus 3 (4.0%) %). The isolated fungi were tested for antifungal sensitivity to 6 antifungal discs. A. niger shows good susceptibility to clotrimazole (100%), nystatin (90%), and fluconazole (83.3%) but was resistant to griseofulvin, terbinafine, and ketoconazole. A. flavus and A. fumigatus also show good sensitivity to clotrimazole, nystatin, and fluconazole. Candida albicans was only susceptible to clotrimazole but resistant to other tested antifungal disc. Rhizopus and Penicillum species showed 100.0% sensitivity to clotrimazole but also resistant to other tested antifungal discs. Conclusions: This study revealed that Aspergillus and Candida species were the most common fungal pathogens causing otomycosis. A. niger is the predominant fungal isolate. Molds isolates showed good susceptibility to clotrimazole, while highest resistance was to terbinafine and ketoconazole. Yeasts isolates showed highest susceptibility to clotrimazole and highest resistance to nystatin and fluconazole.

Prevalence and antimicrobial susceptibility of Salmonella enteritidis and Salmonella typhimurium isolated from hen eggs and quail eggs in Karaj, Iran.

Different Salmonella serotypes are considered one of the most important food pathogens in the world. Poultry meat and eggs are the primary carriers of Salmonella in human populations. This study aimed to estimate the Salmonella enteritidis and Salmonella typhimurium contamination rates of retail hen and quail eggs in Karaj, Iran. Moreover, the antimicrobial resistance patterns of the strains were evaluated, and the efficiency of the standard culture method and multiplex polymerase chain reaction (m-PCR) were compared. In this descriptive cross-sectional study over 1 year (Jan-Dec 2022), 150 commercial and 150 backyard hen eggs and 300 commercial quail eggs, without cracks and fractures, were collected randomly from best selling groceries in Karaj city. All samples were examined for Salmonella contamination independently by standard culture and m-PCR approaches. A standard disc diffusion method was employed to assess the antimicrobial susceptibility of the strains against 18 antimicrobial agents. Out of 300 examined eggs, 2 S. enteritidis strains were isolated from the shell of backyard hen eggs. The same serotype was also detected in the contents of one of these two eggs. One S. typhimurium was isolated from the shell of a commercial hen egg. Overall, the Salmonella contamination of the shell and contents was 1% and 0.3%, respectively. Salmonella was not isolated from the eggshells or the contents of the quail eggs. There was complete agreement between the results of m-PCR and the standard culture methods. Among the 18 tested antibiotics, the highest resistance was recorded for colistin (100%), followed by nalidixic acid (75%). As most Salmonella spp. are associated with human food poisoning, continuous surveillance is required to effectively reduce the risk posed by contaminated poultry eggs. Furthermore, mandatory monitoring of antimicrobial use on Iranian poultry farms is recommended.

Comparison of Rapid Antibiotic Susceptibility Test Method Directly from Blood Culture Bottle with Standard Disc Diffusion Method

Aim: Early determination of antimicrobial susceptibility of sepsis pathogens is important. In this study, we aimed to compare the standard disc diffusion method with the rapid antimicrobial susceptibility testing (RAST) method performed directly from blood culture bottles. Material and Methods: Bacteria isolated from samples that gave a positive signal on the blood culture device between April 2019 and September 2019 were included in the study, and antimicrobial susceptibilities were determined by the standard disc diffusion method and the RAST method. Categorical agreement, small error, large error, very large error, and area of technical uncertainty ratios were recorded. Results: A total of 103 bacteria including 19 S. aureus, 10 Enterococcus spp. and 24 E. coli, 24 K. pneumoniae, 13 P. aeruginosa, and 13 A. baumannii were included in the study. When the RAST method was compared with the standard disc diffusion method, 100% agreement was found between the methods against imipenem, meropenem, gentamicin, and trimethoprim-sulfamethoxazole in E. coli isolates at all hours evaluated, and against meropenem in K. pneumoniae isolates at the 6th and 8th hour. For S. aureus and P. aeruginosa isolates, very major errors were found in the RAST results. For A. baumannii isolates, 100% agreement between methods was observed for many antibiotics. Conclusion: It was concluded that the RAST method is a simple and inexpensive test for life-threatening infections such as sepsis. It was also felt that similar studies should be carried out with a large number of isolates, as compliance rates vary depending on the bacteria tested.

Application of Novel Ruthenium (II) Polypyridyl Complexes as Robust DNA Probes, Optical Material and Antimicrobials-An Experimental and DFT Approach.

The nature of the interaction of DNA with heteroleptic Ruthenium (II) Polypyridyl complexes of the type [Ru (A)2TPIP]2+, where TPIP = 2-(1-p-tolyl-1H pyrazol-4 -yl)-1H-imidazo [4, 5-f[1. 10] phenanthroline and A = 1,10 phenanthroline (1),4,4'-dimethyl-1,10-ortho Phenanthroline (2),2,2' - bipyridine(3) and 4, 4' dimethyl 2, 2'- bipyridine (4), has been investigated by experimentaland molecular docking approaches. The order of the DNA binding affinities of the synthesised complexes is 1 > 2 > 3 > 4. The findings imply that the unsubstitutedcomplex has a better affinity to bind with DNA than the substituted (dmp and dmb) emphasizing the significance of the auxiliary ligand. Additionally, as the medium's ionic strength drops, the DNA/Ru ratio rises, or when water is displaced by glycerol, the intercalation of complexes into DNA increases. DFT calculations at the B3LYP/LANL2MBlevel was used for molecular geometry (Ground State) and electronic characteristic calculations. The HOMO-LUMO gap of the Ru [II]complex is less than the intercalator and hence kinetically labile. Among the complexes, the bpy complex has shown utmost non-linear optical properties (α = -153.9099 10-24esuand β = 3.8498 10-30esu). The docking study shows the significance of the Metal-intercalator's shorter length may increase DNA binding affinity. This study divulges that the Ruthenium (II) polypyridyl complexes bind to DNA preponderantly by intercalation supporting Viscosity studies. All the complexes have a considerable attraction for guanine. The standarddiskdiffusion method reveals that complexes (1,2,3 and 4) have good antibacterial activity.

Prevalence, molecular identification and determination of antibiotic susceptibility of methicillin-resistant Staphylococcus aureus in raw meat

Objective: The aim of this study was to determine the prevalence, molecular identification, and antibiotic susceptibility of MRSA in raw meats of retail sale in Balikesir, Turkey. Materials and Methods: A total of 250raw meat samples (beef n=100, chicken n=100, and turkey n=50) were collected from various supermarkets. Mueller-Hinton Broth medium containing 6.5% NaCl was used for pre-enrichment and Baird Parker Agar (BPA) was used as a selective medium. Polymerase Chain Reaction technique was used to confirm the suspected colonies with the nuc gene for S. aureus and the mecA gene for MRSA. Kirby-Bauer standard disc diffusion method was applied for antibiotic susceptibility of MRSA. Results: Of the 250 investigated raw meat samples, 21.2% were positive for S. aureus, which comprised 31% beef, 14% chicken, and 16 %turkey samples. Of the 250 investigated raw meat samples, 4% were positive for MRSA, which comprised 6% beef, 3% chicken, and 2% turkey samples. All MRSA isolates were found to be resistant to penicillin, sulfamethoxazole, trimethoprim, cefoxitin, and oxacillin, but they were susceptible to vancomycin. Conclusion: In recent years, MRSA has been called a zoonotic pathogen that poses a serious risk for food safety and public health. Therefore, we believe that this study will shed light on new studies on the prevalence of MRSA in various animal-originated foods.