Agar Disc Diffusion Method Research Articles

Occurrence of Antimicrobial-Resistant Enterococcus spp. in Healthy Chickens Never Exposed to Antimicrobial Agents in Central Italy.

Enterococci are part of the natural flora of the gastrointestinal tract of mammals, including humans, birds and invertebrates. They can cause infection, mainly among hospitalized patients, as well as acquire and transfer antimicrobial resistance genes. The present study allowed the isolation of 98 Enterococcus (73.47% E. faecium, 23.47% E. faecalis, 3.06% E. avium) strains from 120-day-old healthy chickens that had never been treated with antimicrobials. Their antimicrobial resistance was evaluated by the agar disk diffusion method; high-level aminoglycoside (streptomycin and gentamicin) and vancomycin resistance were established using the microbroth dilution method. The highest percentages of resistant isolates were detected with quinupristin-dalfopristin (88.78%), rifampicin (64.29%), tetracyclines (45.92%), and enrofloxacin (41.84%). High percentages of susceptible strains were found with teicoplanin (100%), amoxicillin-clavulanic acid (97.96%), nitrofurantoin (94.90%), ampicillin (92.86%), chloramphenicol (90.82%), and linezolid (88.78%). About 60% of the strains were classified as MDR (multidrug-resistant). Moreover, PCR was carried out to investigate genes encoding for tetracyclines resistance determinants: tet(M), tet(L), tet(O), tet(K), and Int-Tn. Genes were detected in 68 (69.38%) strains: 36 were shown to be resistant with the agar disk diffusion method, while 28 were intermediate, and 2 were susceptible. The present study showed that chickens never treated with antimicrobials potentially harbor enterococci having phenotypic and genotypic characters of antimicrobial resistance.

Synthesis, Characterization and in vitro Antimicrobial Activity of Organotellurium Decorated 10-Membered Tetraazamacrocyclic Complexes of Cobalt(II)

Three novel organotellurium decorated 10-membered tetraazamacrocyclic complexes of Co(II) were synthesized using template condensation of 1,1-diiodo-1-telluracyclopentane, 1,1-diodo-2-methyl-1-telluracyclopentane and 1,1-diiodo-1,1-diethyltellurium(IV) with 1,2-diaminopropane and cobalt dichloride hexahydrate in dry methanol in 2:2:1 molar ratio. The characterization of the synthesized cobalt(II) complexes was carried out using elemental analysis, spectroscopic studies (IR, proton NMR & proton decoupled carbon NMR) and molar conductance measurements. The results of these studies suggested that the complexes may be formulated as [CoLCl2] where L = {C4H8Te-(NHCH2CH(CH3)NH)}2, {C4H7(CH3)Te(NHCH2CH(CH3)NH)}2 and {(C2H5)2Te(NHCH2CH(CH3)NH)}2. The synthesized complexes were also screened for antimicrobial activity using broth microdilution and agar disc diffusion methods.

Direct effect of ultra diluted ethanolic extract of Apis mellifica on Escherichia coli and Staphylococcus aureus in Gallus gallus domesticus embryo model

Urinary tract infection and other infections caused by multi-drug resistance strains have increased significantly, creating a need to investigate alternative medicine for therapeutic purposes. Our aim is to determine whether Apis mellifica 6C (an alternative ultra-diluted medicine) can counteract the detrimental impact of Escherichia coli ATCC 25922, Escherichia coli MDR and Staphylococcus aureus ATCC 25923 in Gallus gallus domesticus embryos with regard to their morbid anatomical changes and cytokine alterations. Anti-microbial activity of Apis mellifica 6C against the ATCC and MDR strains was examined by Agar Disc Diffusion method. The bacterial strains were inoculated on 15th day embryonated chick egg model and the alteration in cytokine gene expressions (IL-10 and IFN-γ) was examined by RT PCR method. In disc diffusion method, Apis mellifica induced zone of inhibition which was prominent in case of all mentioned bacteria. In case of embryo model, the most notable finding is that after being challenged with Apis mellifica 6C, the IFN-γ and IL-10 gene expression of E. coli ATCC, MDR E. coli and S. aureus ATCC were all remarkably decreased than the control set. Similar interesting outcomes were also found in the morbid anatomy of the chick embryo. In cases of urinary tract infection and other infections, Apis mellifica 6C appears to be efficient and beneficial.

The Control of Pseudomonas syringae pv. tomato, Causing Bacterial Spot Disease in Tomato, by Different Plant Essential Oils

Seed-borne Pseudomonas syringae pv. tomato causes bacterial spot disease in tomatoes and causes serious economic losses by affecting yield and quality in tomato cultivation. In this study, the effect of essential oils obtained by distillation from Mentha longifolia, Thymus migricus, Salvia hydrangea and Artemisia absinthium and Achillea arabica plants on the control of P. syringae pv. tomato was investigated. The antibacterial activities of plant essential oils against P. syringae pv. tomato were tested by the in vitro agar disk diffusion method. Additionally, minimum inhibitory concentrations at which plant essential oils inhibit the growth of Pst 76 were determined. It was determined that all oils created an inhibition zone between 4.0-30.0 mm against the disease agent and the highest activity was obtained from application with the oil of the T. migricus plant. It was determined that the oils obtained from T. migricus and M. longifolia plants had higher antimicrobial activity than methylmycin in the control group. In line with the results obtained, disease control with essential oils has been seen as an alternative method that can be included in integrated control programs.

Manganese 11 Complexes of Salycilhydroxamix Acid with Aniline and Ammonia with Its Properties the Effect on Microorganism

The salicylichyroxamic acid (SHA) its complex of Mn (II) along with their mixed ligand complexes of ammonia and aniline were prepared in high yields. Both the ligands and complexes were both soluble in methanol, DMSO but are insoluble in chloroform and distilled water. Their melting point were high and falls between 1910C - 400 0C. The IR spectra of the synthesized compound showed the coordination of the ligand through the oxygen of the phenolic NOH and C=O functional groups to the metals. The electronic spectra of the complexes in methanol showed some observable absorption bands of the following transitions; for Mn(SHA) complex transition is at 6A1g(s)→ 4T2g, that of Ammonia mixed complex 6A1g(s)→ 4T2g and that of Aniline mixed complex 6A1g(s)→ 4T2g. All the transitions were in the range of those observed for octahedral complexes. The antimicrobial activity of the ligand SHA (C7H7NO3), the complexes and reference drug was study against two bacterial species staphylococcus auerus and Escherichia coli, and one fungi species candida albicans. This was done using agar disc diffusion method measuring the diameter of inhibitions zone for each compound. The Mn (II) complexes produced in this study showed significant activity against the used micro-organisms. Therefore, they have potential application as anti-microbial agent.

Antimicrobial Properties of Cola Nitida

The antimicrobial evaluation of ethanol, methanol and aqueous extracts of Cola nitida on Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli was experimented. The assay was carried out by agar disc diffusion method. Results showed that the ethanol, methanol and aqueous extracts of the seed were found to be of a relatively higher effect having a zone of inhibition of 5mm against the samples of S. aureus than the other bacteria at the concentration of 400mg/mm. None of the extract was active against P. aeruginosa. E. coli showed a zone of inhibition of 3mm with ethanolic extract but showed a lower zone of inhibition with both methanol and aqueous extract. When compared to standard antibiotics such as septrin, amoxicillin, tetracycline, ampiclox and doxycycline, all the extracts had a high zone of inhibition of 5mm on S. aureus except for doxycycline which showed a higher zone of inhibition on all the test organisms. This antimicrobial property showed by the seed extracts on some of the organisms is an evidence of the ethno-medicinal uses of the plants due to the presence of some phytochemicals such as saponins, tanins, and alkaloids among others. For effective utilization of these Cola seeds as well as other relevant parts of the Cola plant, further research has been recommended.

Biopesticide potential of Anisomeles indica Kuntze leaf essential oil and its nanoemulsion against bacterial blight - Xanthomonas strains

The objective of this study was to examine the chemical composition of essential oil A. indica leaves and its nanoemulsion, and evaluation of potential for use as a biopesticide. Essential oil of A. indica extracted from fresh leaves was found to be 99.97% composed of 59 components, according to GC-MS analysis. A non-ionic surfactant Tween 80 and the essential oil of A. indica were combined to create a stable nanoemulsion using sonication method. A long durable stable nanoemulsion was obtained after thirty minutes of sonication, and it was examined using TEM (Transmission electron microscopy), DLS (Dynamic light scattering), and FTIR (Fourier transform infrared spectroscopy) analyses. To consider its practical applications, other factors such as stability, viscosity, pH, turbidity, and creaming index were also investigated. Antibacterial properties of essential oil and nanoemulsion were evaluated against bacterial blight plant pathogens Xanthomonas oryzae and Xanthomonas citri. The MIC (Minimum inhibitory concentration) was determined using the broth microdilution method, and the anti-Xanthomonas activity was assessed utilizing by agar disc diffusion method. Using the crystal violet (CV) technique, inhibition of biofilm formation and development were evaluated. Disturbance of bacterial membrane permeability was confirmed by estimating the proteins and nucleic acids (DNA, and RNA) leakage from the cell membrane. Greenhouse studies using rice/paddy plants were conducted to demonstrate the antibacterial potential of essential oil and nanoemulsion, using RNR-15048 rice cultivar by seed treatment and foliar spray groups. Results of the investigations suggest that, when the essential oil was transformed into a nanoemulsion, its antibacterial effect against bacteria was significantly increased, that might be attributed to the essential oil enhanced ability to penetrate the bacterial cells. Essential oil of A. indica and its nanoemulsion reduced rice bacterial blight disease by 84%and pathogen-virulence by 92%, and promoted the growth and development of rice/paddy seedlings. These results confirm that A. indica essential oil and its nanoemulsion possess anti-bacterial blight properties, without affecting growth and development of host plants. Essential oil of A. indica and its nanoemulsion could be used as biopesticide to control Xanthomonas induced bacterial blight diseases in crop plants either by using for seed treatment or as a foliar spray.

Synthesis, evaluation, and in silico studies of imidazolium and pyridinium-based ionic liquids with Dioctyl succinamic acid anion for enhanced antibacterial applications

A substantial public health risk is bacterial infections, but the effectiveness of antibiotics has declined due to their overuse. In the quest for effective antimicrobial agents, Ionic liquids (ILs) have emerged as promising candidates. We have described the synthesis and comparison of pyridinium- and imidazolium-based ILs using bromide and dioctyl succinamate (DOSA) anions. These synthesized ILs were tested for their antibacterial efficacy against gram-positive Staphylococcus aureus, gram-negative Escherichia coli, and Pseudomonas aeruginosa using the agar disc diffusion method. The ILs based on Imidazolium cation showed better antibacterial activities against Staphylococcus aureus. The least MIC values of 0.244 mM and 0.488 mM are shown by [C88im] [Br] and [C88im] [DOSA] respectively, showing the key effect of a counter ion with Imidazolium ILs.

Occurrence of Antimicrobial-Resistant Bacteria in Intestinal Contents of Wild Marine Fish in Chile.

Antimicrobial-resistant bacteria (ARB) from the intestinal contents of wild fish may have a relevant ecological significance and could be used as indicators of antimicrobial-resistance dissemination in natural bacterial populations in water bodies impacted by urban contamination. Thus, the occurrence of ARB in the intestinal contents of pelagic and demersal wild fishes captured in anthropogenic-impacted Coquimbo Bay in Chile was studied. Culturable counts of total and antimicrobial-resistant bacteria were determined by a spread plate method using Trypticase soy agar and R2A media, both alone and supplemented with the antimicrobials amoxicillin, streptomycin, florfenicol, oxytetracycline and ciprofloxacin, respectively. Heterotrophic plate counts of pelagic and demersal fishes ranged from 1.72 × 106 CFU g-1 to 3.62 × 109 CFU g-1, showing variable proportions of antimicrobial resistance. Representative antimicrobial-resistant isolates were identified by 16S rRNA gene sequencing, and isolates (74) from pelagic fishes mainly belonged to Pseudomonas (50.0%) and Shewanella (17.6%) genera, whereas isolates (68) from demersal fishes mainly belonged to Vibrio (33.8%) and Pseudomonas (26.5%) genera. Antimicrobial-resistant isolates were tested for susceptibility to 12 antimicrobials by an agar disk diffusion method, showing highest resistance to streptomycin (85.2%) and amoxicillin (64.8%), and lowest resistance to oxytetracycline (23.2%) and ciprofloxacin (0.7%). Only furazolidone and trimethoprim/sulfamethoxazole were statistically different (p < 0.05) in comparisons between isolates from pelagic and demersal wild fishes. Furthermore, an important number of these isolates carried plasmids (53.5%) and produced Extended-Spectrum-β-lactamases (ESBL) (16.9%), whereas the detection of Metallo-β-Lactamases and class 1-integron was rare. This study provides evidence that wild fish are important reservoirs and spreading-vehicles of ARB, carrying plasmids and producing ESBLs in Chilean marine environments.

Exploring a new phyto-derived nanoparticle for targeting bacterial protein EF-Tu: an integrated approach to develop antimicrobial drug

ABSTRACT The application of antibiotic medicine to save numerous lives is in jeopardy due to the alarming elevation in antibiotic-resistant organisms as a consequence of improper and imprudent usage of antibiotics. This study investigated the antibacterial efficacy of pelargonidin (PG) by employing a cost-effective nano-formulation-based targeted drug delivery system as an alternative to conventional strategies. The precise targeting of bacteria was made easier by synthesizing nano-particles of phyto-product pelargonidin (NPG) by employing poly-lactide-co-glycolide (PLGA), a biodegradable polymer. The physico-chemical characterization of NPGs was performed via AFM study and the antibacterial efficacy of NPGs tested against Escherichia coli and Staphylococcus aureus was assessed by agar disc diffusion method. Additionally, the docking platform explored in this study enabled the prediction of the ability of PG to occupy the binding pocket of EF-Tu (elongation factor thermo unstable), a vital bacterial protein that operates on a translational level. The overall results implicate that NPG was an effective drug candidate against the gram-negative bacteria E. coli and the gram-positive bacteria S. aureus according to the diameter of the inhibition zone (23 ± 0.82 mm: E. coli and 22.67 ± 1.25 mm: S. aureus). Furthermore, in silico analysis revealed that the NPG-EF-Tu complex had an excellent docking score of −9.13 Kcal/mol, indicating key amino acid residues required for interaction, and anticipating the signaling component/s involved that may be hindered by NPG, thereby leading to a decline of bacterial growth. The core phyto-compound of NPG (pelargonidin) could effectively bind to EF-Tu thereby exercising strong antimicrobial efficacy against both E. coli and S. aureus making it a potential alternative to the usage of commercial antibacterials with a history of drug-resistance.

Coaxial electrospun PVA-SAP functional nanofibers embedded with betel leaf extract for enhanced germicidal activity and breathability

This study investigates the formation of coaxial electrospun nanofibrous membrane with enhanced germicidal activity and breathability using superabsorbent polymer and polyvinyl alcohol integrated with betel leaf extract and its utilization for developing performance textiles. The functional nanofibrous membrane was fabricated through the coaxial electrospinning technique and characterized for the intended applications. The morphological investigation of the developed nano-membrane using scanning electron microscopy revealed the formation of regular nanofibers with diameters ranging from 154 to 200 nm. The FTIR spectra suggested the existence of functional compounds in the nanofibers from their characteristic peaks. The presence of the bioactive compounds in the ethanolic extract of betel leaf was explored using phytochemical screening. The analysis of antibacterial activity against S. aureus and E.coli using the agar disc diffusion method showed an enhanced zone of inhibition with a maximum dimension of 27 mm and 24 mm against S. aureus and E.coli, respectively. The developed coaxial nanofibrous membranes also demonstrated acceptable particle barrier performance with greater than 95 % efficiency and a superior tensile strength of 99.5 N. Besides, the improved moisture management and air permeability of coaxial nano-membranes embedded with betel leaf extracts suggested an easy transfer of fluid and moisture vapor from the body to the environment via the membrane. Hence, the improved germicidal activity with acceptable particle filtration efficiency and enhanced breathability of the developed coaxial electrospun nano-membranes indicated their potentiality of utilizing them in designing performance textiles with simultaneous barrier performance and breathability for comfort.

Molecular detection and antibiogram of Shiga toxin-producing Escherichia coli (STEC) from raw milk in and around Bahir Dar town dairy farms, Ethiopia

Illnesses associated with consuming infected milk and milk products are a widespread problem in low and middle-income countries. Shiga toxin-producing Escherichia coli (STEC) is a bacterium commonly found in raw milk and causes foodborne diseases ranging from mild diarrhea to severe hemorrhagic colitis and hemolytic uremic syndrome. This study aimed to investigate the virulence gene and antimicrobial resistance profiles of Shiga toxin-producing E. coli strains isolated from raw milk in dairy farms in and around Bahir Dar town. Raw milk samples (n = 128) collected from December 2021 to July 2022 were cultured, and E. coli strains were isolated using standard methods. Shiga toxin-producing E. coli strains were identified genotypically by the presence of the virulence markers using a single-plex polymerase chain reaction. The antibiotic susceptibility testing of Shiga toxin-producing E. coli isolates was done by the agar disk diffusion method. In total, 32 E. coli isolates were recovered from milk samples from lactating animals. PCR screening of these isolates resulted in 19 (59.3%) positives for Shiga toxin-producing E. coli. The stx2 gene was detected in 53% of cases, followed by stx1 (31%) and eae (16%. The STEC isolates were highly sensitive to ciprofloxacin (94.7%) and kanamycin (89.5%), while exhibiting significant resistance to amoxicillin (89.5%) and streptomycin (73.7%). The present study points out the occurrence of virulent and antibiotic-resistant Shiga toxin-producing E. coli strains in raw milk that could pose a potential risk to public health. Further analysis by whole genome sequencing is necessary for an in-depth assessment and understanding of their virulence and resistance factors. Moreover, large-scale studies are needed to identify the prevalence and potential risk factors and to prevent the spread of antibiotic-resistant STEC strains in the milk production chain.

Molecular investigation of exoU and exoY virulence genes in Pseudomonas aeruginosa collected from hospitalized patients in North of Iran: A descriptive-analytical study

Objective: To investigate the frequency of exoU and exoY genes in patients with Pseudomonas aeruginosa infection. Methods: In this study, 100 clinical isolates of Pseudomonas aeruginosa were collected from patients hospitalized in educational- therapeutic hospitals and were identified using standard microbiological tests. Then, the antibiotic resistance pattern of the isolates was determined by the disk agar diffusion method. The bacterial DNAs were extracted by the alkaline lysis method. Finally, the presence of exoU and exoY genes was evaluated by the PCR test. Results: In this study, 47%, 72%, 29%, 39%, 40%, and 44% of the isolates were non-susceptible to piperacillin, aztreonam, ceftazidime, imipenem, tobramycin, and ciprofloxacin, respectively. In addition, 95% and 93% of the clinical isolates carried the exoU and exoY genes. Blood and fecal isolates had both virulence genes, while only one wound isolate had neither genes. Meanwhile, all urinary isolates contained the exoY gene and only one isolate lacked the exoU gene. Also, 88 isolates simultaneously had both exoU and exoY genes. Conclusions: High prevalence of exoU and exoY genes in this region indicates a significant role of type III secretion system in pathogenesis of Pseudomonas aeruginosa. The type III secretion system may be a suitable target to reduce the pathogenicity of this bacterium.

Antimicrobial Susceptibility Pattern of Bacterial Pathogens in Our Setup: Ear, Nose and Throat Perspective

With a high prevalence of infections involving the ear, nose, and throat, and the occurrence of drug resistance the antimicrobial susceptibility pattern of bacterial pathogens is of immense importance. Objective: To determine the antimicrobial sensitivity profile of pathogenic bacteria isolated from representative infected areas of patients with ear, nose, and throat infections. Methods: This cross-sectional observational study was conducted at Ear, Nose and Throat (ENT) Outpatient Department (OPD), Capital Hospital Islamabad, over two years. The sample included 639 pathogenic bacterial culture specimens, grown from the representative infected ear, nose, or throat of patients who attended ENT outpatients of the hospital. The bacterial cultures were subjected to the standard disc agar diffusion method to know the antimicrobial susceptibility profile. Data collected included the patient’s age, gender, area/ site of infection, bacterial pathogen isolated, and sensitivity to antibiotics. Results: The sample included 49.30% males and 50.70% females and mean age of 30.13±19.24 years. Gram-positive organisms were predominant [n=441, (69.01%)] with Staphylococcus aureus being the commonest isolate (67.92%) followed by Pseudomonas spp. (26.13%). Gram-positive isolates were sensitive to Cefoperazone+Sulbactam, Ceftazidime, Cefoperazone, Amikacin, Pipercillin+Tazobactam, Vancomycin, Gentamycin, Linezolid, Amoxicillin + Clavulanate, and Ceftriaxone with resistance to Cefixime, while the Gram-negative isolates were sensitive to Vancomycin and Meropenum, Ciprofloxacin, Levofloxacin, Ceftriaxone and Ceftazidime and highly resistant to Cefixime, Cefuroxime, Amoxicillin+Clavulanate and Co-trimoxazole. Conclusions: Since ENT infections are predominated by Staphylococcus aureus and Pseudomonas spp. When unavoidable the empirical therapy should cover these pathogens, however culture and sensitivity studies are justified keeping in view the growing resistance to antimicrobials.

Chemical constituents of the roots of Kniphofia schimperi and evaluation of their antimicrobial activity

Kniphofia schimperi is one of the endemic plants of Ethiopia and is widely used for the treatment of microbial infections. However, the biological and phytochemical information pertaining to this plant has not been reported so far. Anticipated by these claims, the chromatographic isolation of the CHCl3/CH3OH (1:1 v/v) extract of the roots of K. schimperi afforded five compounds, viz., knipholone (1), asphodeline (2), β-sitosterol (3), 9-pentacosenoic acid (4), and nonacosanoic acid (5). The structures of the isolated compounds were identified based on their NMR (1D and 2D) spectral data analysis and comparison with reported literature data. The crude extract and isolated compounds were evaluated for their in vitro antimicrobial activity against four bacterial strains (Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Bacillus cereus) and a fungal strain (Candida albicans) using the agar disk diffusion method. The test samples showed moderate antimicrobial activity, with the highest activity observed for compound 3 (with a zone of growth inhibition of 15.5 ± 0.71 mm) against S. typhimurium.

The Home Environment Is a Reservoir for Methicillin-Resistant Coagulase-Negative Staphylococci and Mammaliicocci.

Coagulase-negative staphylococci (CoNS) and mammaliicocci are opportunistic human and animal pathogens, often resistant to multiple antimicrobials, including methicillin. Methicillin-resistant CoNS (MRCoNS) have traditionally been linked to hospitals and healthcare facilities, where they are significant contributors to nosocomial infections. However, screenings of non-hospital environments have linked MRCoNS and methicillin-resistant mammaliicocci (MRM) to other ecological niches. The aim of this study was to explore the home environment as a reservoir for MRCoNS and MRM. A total of 33 households, including households with a dog with a methicillin-resistant staphylococcal infection, households with healthy dogs or cats and households without pets, were screened for MRCoNS and MRM by sampling one human, one pet (if present) and the environment. Samples were analyzed by a selective culture-based method, and bacterial species were identified by MALDI-TOF MS and tested for antibiotic susceptibility by the agar disk diffusion method. Following whole-genome sequencing, a large diversity of SCCmec elements and sequence types was revealed, which did not indicate any clonal dissemination of specific strains. Virulome and mobilome analyses indicated a high degree of species specificity. Altogether, this study documents that the home environment is a reservoir for a variety of MRCoNS and MRM regardless of the type of household.

Molecular Determination of Resistance Gene in Methicillin Resistant Staphylococcus aureus (MRSA) Isolated from Skin and Wound

The wide spread use of antibiotic resulted in the development of resistance to antibiotics through acquisition of the mobile cassette chromosome carrying the Methicillin-resistant gene mecA. The study was aimed to characterize the resistance gene in Methicillin resistant Staphylococcus aureus (MRSA) isolated from skin and wound samples in Kano Metropolis, Northwestern, Nigeria. A total of 235 S. aureus isolates were identified and subjected to MRSA screening. MRSA were phenotypically identified by antibiotic susceptibility testing using agar disc diffusion method. The suspected MRSA were subjected to polymerase chain reaction (PCR). The PCR products were subjected to gel electrophoresis and a DNA ladder were loaded into the gel wells. The gel was examined for the presence of specific amplicons of the expected size for mecA, which is 192bp. Out of a total of 235 isolates of Staphylococcus aureus, only 11 (4.7%) strains were found to be Methicillin resistant Staphylococcus aureus (MRSA). Five out of the 11 isolates show the presence of DNA bands of the expected size for MecA gene which indicated the presence of the resistance genes in the bacterial isolates. It is concluded that MecA gene is one of the gene responsible for methicillin resistance in MRSA.

Occurrence and distribution of two bacterial brood diseases (American and European foulbrood) in US honey bee colonies and resistance to antibiotics from 2015 to 2022

Here, we present a retrospective study on honey bee brood diseases in the USA. The Bee Disease Diagnostic Laboratory (BDDL) in the USDA-ARS Beltsville Bee Research Laboratory received a total of 4790 brood samples between 2015 and 2022 from U.S. State Apiary Inspectors and beekeepers. Samples from 49 states were analyzed by microscopy for the presence and prevalence of two bacteria, Melissococcus plutonius and Paenibacillus larvae, causing European foulbrood (EFB) and American foulbrood (AFB) diseases, respectively. Samples that tested positive for AFB were cultured and subjected to antibiotic susceptibility tests via the agar disc diffusion method to determine their resistance to tetracycline (Terramycin®) and tylosin (Tylan®) antibiotics. A comprehensive data analysis was conducted at multiple levels, including state, month, year, nationwide, and climate region. Among the 49 states examined, EFB was identified in 44 states, while AFB was found in 31 states. Infection levels vary across states, ranging from 0% to 63.6% for EFB and from 0% to 54.8% for AFB. The national average of EFB (19.2%) was significantly (p < 0.001) higher than AFB (8.6%). Contrary to AFB, significant yearly increases (p < 0.001) were identified for EFB from 2015 to 2022. Furthermore, significant monthly variations were recorded for both brood diseases, with the highest occurrence of EFB observed from April to July. States with the lowest infection rates of both diseases were NV, ND, MS, AK, and AZ. The South U.S. climate region, which comprises six states, had the highest and lowest EFB and ABF infections, respectively. On a nationwide scale, the AFB resistance to tetracycline (38%) was significantly (p < 0.001) higher than the resistance to tylosin (27%).

DEVELOPMENT OF THE PHARMACEUTIC CRYSTALLIZATION PROCESS USING PLASMODIUM FALCIPARUM, A DERIVATIVE OF THIOSEMICARBAZONE

Objective: The current study was designed with the goal of analyzing novel derivatives of organic and semi-organic NLO molecules that are just entering this field as the foundation for future therapeutic development. Methods: Thiosemicarbazones (TSC) are semicarbazide analogs that have sulfur atoms in place of oxygen atoms. The greatest number of therapeutic treatments for various disorders are also being used carbonyl compounds. These two types of organic compounds were combined, and their replacement with crystal growth procedures using solution growth was tested as an antibiotic for a few fastidious and nonfastidious species. The preparation of meta-substituted benzaldehydes using TSC. Tests were conducted with this single component. The following experimental technique was used to determine the antibacterial activity of Plasmodium falciparum. Half-inhibitory maximum (IC50) by calculation technique, cell viability % calculation method, and MTT assay by colorimetric method. Results: Method using agar discs. Using the agar disc diffusion method to measure the inhibition zone width and comparing the minimal inhibitory concentration (MIC) and inhibition zone width of available antibiotics against the aforementioned organism using data from the EUCAST and NCCLS databases, The absolute, relative, and mound slope values of an antibiotic that is currently on the market may be determined using the GraphPad Prism software; the epidemiological cutoff value can be determined using the ECOF Finder software; and the nature of the antibiotic can be determined using the WHONET 5.6 software. The newly developed antibiotics’ size and structure are contrasted with the structures of commercially available antibiotics and living organisms. Conclusion: The design of new drugs using novel derivatives of organic and semiorganic NLO molecules is based on the in vitro method of analysis, which has recently been introduced to this field. P. falciparum has an extremely low MIC value (0.625 μg/mL) against TSCMNB. The MIC break points are always larger than, not equal to, the MIC values and fall within the range of 110 μg/mL–130 μg/mL. We concluded that all of the novel compounds exhibit a susceptible form of inhibition.

Antimicrobial resistance patterns, virulence genes, and biofilm formation in enterococci strains collected from different sources

BackgroundCurrently, antibiotic-resistant strains of Enterococcus are considered to be one of the critical health challenges globally. This study aimed to investigate the antibiotic susceptibility pattern, biofilm formation capacity, and virulence genes of enterococci isolated from different sources.MethodsIn this cross-sectional study, environmental and fecal samples were collected from the hospital environment, volunteers, and hospital staff from October 2018 to August 2019. The isolates were identified by morphological and biochemical tests (gram staining, catalase, bile resistance, esculin hydrolysis, carbohydrate fermentation, growth in 6.5% NaCl, Pyrrolidonyl arylamidase, arginine dehydrolase), and PCR for ddl gene. An antimicrobial susceptibility test was performed by the standard disk agar diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Quantitative microplate assays were used to assess biofilm production. The bacterial DNAs were extracted by alkaline lysis method and polymerase chain reaction technique was used detect the esp, ace, and efaA virulence genes.ResultsOut of 145 isolates, 84 (57.9%) were identified as E. faecalis and 61 (42.1%) as E. faecium. Resistance to kanamycin and quinupristin-dalfopristin was 82.1% (69/84) and 85.7% (72/84), respectively, in E. faecalis isolates. Out of 61 E. faecalis isolates, 38 (62.4%) were resistant to kanamycin. Among the E. faecalis isolates, esp was the most dominant virulence gene (73.80%), followed by efaA, and ace, which were detected in 60.71%, and 30.95% isolates, respectively. In total, 68.27% of the strains were biofilm producers. Further, esp and efaA genes were more frequently found among E. faecalis strains with moderate and strong biofilm biomass.ConclusionsAccording to the findings of our study, enterococci strains isolated from different samples possess distinctive patterns of virulence genes. The esp, ace, and efaA genes were more prevalent among E. faecalis than E. faecium. Besides, the high level antibiotic resistance of normal flora and environmental enterococci strains is alarming the researchers.