Disc Diffusion Method Research Articles

Virulence, Susceptibility Profile, and Clinical Characteristics of Pathogenic Coagulase-Negative Staphylococci.

Background Coagulase-negative staphylococci (CoNS) are emerging as clinically significant pathogens. A high proportion of methicillin resistance along with intensebiofilm-producing abilityrender CoNS-related infections challenging to treat. This study was undertaken to investigate the mechanisms of methicillin resistance, identify genes encoding for virulence, and their association with clinical outcomes among clinical isolates of Staphylococci in a tertiary care center. Methods A total of 203 clinical isolates were included in this study. Susceptibility to various antibiotics was determined by the disc diffusion method. Methicillin resistance was screened using cefoxitin disc, mecAand mecC genes were detected using polymerase chain reaction (PCR). PCR was performed to detect five virulence genes:atlE, aap, fbe, embp, and icaAB. Staphylococcal cassette chromosome mec (SCCmec) types were identified by multiplex PCR. Statistical analysis was performed using SPSS software (IBM Inc., Armonk, New York). The Chi-squared test was used to compare the distribution of virulence genes among methicillin-susceptible resistant CoNS. A p-value of less than 0.5 was considered significant. Results In the current study, 60% (122/203) of CoNS were methicillin-resistant, and SCCmec type Iwas the most common. Among the 203 CoNS, 24.6% (50/203) isolates harbored one or more virulence genes in them. Conclusion CoNS have relatively low virulence as only 24.6% of isolates carried the virulence genes. Nevertheless, the variety of diseases linked to these species indicates the necessity for accurate identification and precise reporting ofantimicrobial susceptibility to avoid adverse outcomes.

In Vitro and In Vivo Evaluation of Electrospun PVA Nanofiber Containing ZnO/Curcumin for Wound Healing Application.

The development of biocompatible wound dressings containing therapeutic agents to accelerate wound healing is an interesting field of study in biomedical sciences. Polyvinyl alcohol (PVA) nanofibers were loaded with zinc oxide nanoparticles (ZnO NPs) and curcumin (Cur) through electrospinning. Thedressings were characterized by SEM and XRD and FTIR. The antioxidant, antibacterial, and cytotoxic activities Cur/ZnO/PVA nanodressing were evaluated using DPPH radical scavenging assay, disc diffusion method, and MTT assay, respectively. Cur/ZnO/PVA nanodressing showed sustained Cur release about 19.7% and 61.1% after 8h and 168h, respectively. Cur/ZnO NPs/PVA mixture had higher antioxidant potential than PVA, ZnO NPs, and Cur. The dressing showed a good antibacterial effect. The in vivo wound healing effect of different types of prepared dressings, includingPVA, Cur/PVA,Cur/ZnO/PVA, and ZnO/PVAnanofibers, was also investigated. PVA dressing containing Cur/ZnO NPs resulted in the highestincrease of wound contraction in rats. The assembly of Cur and ZnO NPs on PVA nanofibers could propose as an effective delivery method toimprovethe wound healing process. The investigated wound dressing could be commercialized and used on a large scale after proper further studies, including clinical trials.

Antibacterial, Mechanical, and Thermal Properties of Ag, ZnO, TiO2 Reinforced PVA Nanocomposite Fibers

AbstractThis study investigated the effects of concentration and electrospinning parameters on the production of poly (vinyl alcohol) (PVA) nanofibers and examined the impact of reinforcing additives like nano‐sized silver (Ag), titanium oxide (TiO2), and zinc oxide (ZnO) on these nanofibers. The PVA concentration was varied between 3 % and 10 % wt./v, while the flow rate was adjusted to 0.5, 1, and 5 ml/h. The optimal conditions for producing PVA nanofibers are a concentration of 10 % wt./v at a flow rate of 0.5 ml/h and an applied voltage of 9 kV, resulting in nanofibers with an average diameter of 502±0.10 nm. PVA nanofibers reinforced with nano‐sized 3 % wt. Ag, TiO2, and ZnO and electrospun at optimum conditions. The morphological properties were determined using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), and the average fiber diameter was measured with the Image J program. The presence of nanoparticles within the nanofibers was confirmed through Energy Dispersive Spectrometry (EDS) and X‐ray diffraction (XRD). Chemical interactions of functional groups between PVA and ZnO, TiO2, and Ag NPs were analyzed with Fourier Transform Infrared Spectroscopy (FTIR), and thermal behaviors were studied with Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Among the water absorption, Ag‐reinforced PVA nanofibers showed maximum absorbance. Mechanical properties, evaluated through tensile testing, showed the elastic modulus of the nanocomposite fibers to be 38.07±12.01 MPa for PVA/Ag, 88.98±27.5 MPa for PVA/TiO2, and 30.56±9.77 MPa for PVA/ZnO. The antimicrobial activity of the nanoparticle‐reinforced PVA nanofibers was tested using the agar disc diffusion method. The results showed that both Ag and TiO2 reinforced PVA nanocomposite fibers exhibited significant antimicrobial activity (gram–(Escherichia coli) and gram+(Staphylococcus aureus)), with inhibition zones of 8.48±0.08 cm against E. coli and 9.98±0.47 cm against S. aureus for Ag, and 4.32±0.02 cm against E. coli and 3.56±0.05 cm against S. aureus for TiO2.

THE POTENCY OF CINNAMON (Cinnamomum burmanni Blume) LEAF EXTRACT AS A BIOPRESERVATIVE AGENT FOR FOOD SAFETY OF SATE LILIT

ARTICLE HIGLIGHTS- Cinnamon leaf extract combats E. coli in traditional Balinese food.- Natural preservative reduces harmful pathogens in sate lilit.- Cinnamon extract offers a safer alternative to synthetic preservatives.- Active compounds in cinnamon leaves inhibit bacterial growth.- Effective biopreservative for enhancing food safety and quality. ABSTRACTEscherichia coli O157:H7 contamination of the meat used in preparing sate lilit, a favorite traditional food in Bali, Indonesia, has been a great concern for both local people and foreigners. Although C. burmanni has been included in its spice ingredients, active compounds that play a significant role in this pathogen have limitedly been elucidated. The main objectives of this research were to investigate the potency of this plant to control contaminants and elucidate possible compounds that prevent such contaminants by applying the disk diffusion method and LCMS analysis, respectively. The results showed that the leaf extract of this plant inhibited the in vitro growth of E. coli O157:7, with minimal inhibitory concentration (MIC) and LC50 values of 4% and 2.59%, respectively. The LCMS analysis chromatogram showed that the plant extract's most active fraction produced nine peaks, representing nine possible active compounds. Among those, three compounds (Azoxystrobin, Stigmatellin Y, and 2-arachidonoyl glycerol) were suspected of contributing to control contamination, especially by E. coli O157:H7.

Anti-microbial, anti-biofilm, and efflux pump inhibitory effects of ellagic acid-bonded magnetic nanoparticles against Escherichia coli isolates.

The spread of microbial resistance is a threat to public health. In this study, the anti-microbial, anti-biofilm, and efflux pump inhibitory effects of ellagic acid-loaded magnetic nanoparticles (Fe3O4NPs@EA) against beta-lactamase producing Escherichia coli isolates have been investigated. The effects of Fe3O4 NPs@EA on the growth inhibition of E. coli isolates were determined by disc diffusion method and determining the minimum inhibitory concentration was done using broth micro-dilution method. The anti-biofilm effect of nanoparticles was investigated using the microplate method. The efflux pump inhibitory effect of nanoparticles was investigated using cart-wheel method and by investigating the effect of nanoparticles on acrB and tolC genes expression levels. Fe3O4 NPs@EA showed anti-bacterial effects against test bacteria, and the MIC of these nanoparticles varied from 0.19 to 1.56 mg/mL. These nanoparticles caused a 43-62% reduction in biofilm formation of test bacteria compared to control. Furthermore, efflux pump inhibitory effect of these nanoparticles was confirmed at a concentration of 1/8 MIC, and the expression of acrB and tolC genes decreased in bacteria treated with 1/4 MIC Fe3O4 NPs@EA. According to the results, the use of nanoparticles containing ellagic acid can provide a basis for the development of new treatments against drug-resistant E. coli. This substance may improve the concentration of antibiotics in the bacterial cell and increase their effectiveness by inhibiting the efflux in E. coli isolates.

A Health Threat from Farm to Fork: Shiga Toxin-Producing Escherichia coli Co-Harboring blaNDM-1 and mcr-1 in Various Sources of the Food Supply Chain.

The dissemination of resistant pathogens through food supply chains poses a significant public health risk, spanning from farm to fork. This study analyzed the distribution of Shiga toxin-producing Escherichia coli (STEC) across various sources within the animal-based food supply chain. A total of 500 samples were collected from livestock, poultry, the environment, fisheries, and dairy. Standard microbiological procedures were employed to isolate and identify E. coli isolates, which were further confirmed using MALDI-TOF and virulence-associated genes (VAGs) such as stx1, stx2, ompT, hylF, iutA, fimH, and iss. The phenotypic resistance patterns of the isolates were determined using the disc diffusion method, followed by molecular identification of antibiotic resistance genes (ARGs) through PCR. STEC were subjected to PCR-based O typing using specific primers for different O types. Overall, 154 (30.5%) samples were confirmed as E. coli, of which 77 (50%) were multidrug-resistant (MDR) E. coli. Among these, 52 (67.53%) isolates exhibited an array of VAGs, and 21 (40.38%) were confirmed as STEC based on the presence of stx1 and stx2. Additionally, 12 out of 52 (23.07%) isolates were identified as non-O157 STEC co-harbouring mcr-1 and blaNDM-1. O26 STEC was found to be the most prevalent among the non-O157 types. The results suggest that the detection of STEC in food supply chains may lead to serious health consequences, particularly in developing countries with limited healthcare resources.

Diversity and Antibiotic Susceptibility of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae from the Urine of Human Population Using Bacteria-Contaminated Water in Butembo Urban Area (DR Congo, Central Africa)

Aims: This study aims to investigate the extended-spectrum beta-lactamases (ESBLs)-producing Enterobacteriaceae in the human urine samples and to understand the potential influence of the contaminated water the urine donors use. Study Design and Methodology: One hundred urine samples from females and the same number from males were collected from donors of different age groups and analysed. One hundred urine samples from females and the same number from males were collected from donors of different age groups. The enterobacterial isolation was done on CLED agar medium. Their identification was carried out first by the enzymatic technic, then using MALDI–TOF MS method. ESBLs-producing enterobacteria were identified by searching the synergy between Clavulanic acid and 3rd generation Cephalosporins. The antimicrobial susceptibility tests were carried out using the disk diffusion method. Results: In male urine samples, the identified ESBLs-producing strains belong to E. coli, E. agglomerans and K. pneumoniae. They were in 11 samples: 3 from donors aged 20 years or less, 3 also from those aged 21 to 40 years as well as in those aged 41 to 60 years, and 2 in samples from donors aged over than 60 years. In female urine samples, the identified ESBLs-producing strains belong to Escherichia coli, Enterobacter agglomerans, Yersinia frederiksenii, Salmonella typhi and Klebsiella pneumoniae. They were in 27 samples: 3 from donors aged 20 years or less, 9 from those aged 21 to 40 years, 12 from those aged 41 to 60 years, and 3 from donors aged over than 60 years. All the strains were sensitive to Imipenem and resistant to Cefotaxim, Ceftazidin, Amoxicillin+Clavulanic acid and Nitrofurantoin. The Multi-Antibiotic Resistance (MAR) index varied from 0.416 (E. coli strains, youngest male donors) to 0.916 (E. coli strains, old female donors). Most of strains react differently from one antibiotic to another (P<0.05), with the exception of E. coli strains from most samples. Most of the identified ESBLs-producing species have been reported in surface and groundwater the population use. These water resources could play a role in the human urinary tract infections. Conclusion: There is a serious health problem with great MAR indices for all bacterial species identified. Treating water before use could reduce the viability and spreading of ESBLs-producing bacteria and genes into the population.

Antimicrobial Effect of Chitosan Nanoparticles and Allium Species on Mycobacterium tuberculosis and Several Other Microorganisms.

This study evaluates the antimicrobial efficacy of chitosan nanoparticles (CNPs), varying in size, against clinical isolates of Mycobacterium tuberculosis (MTB), E. coli, S. aureus, E. faecalis, and C. albicans, as well as the antimicrobial effects of aqueous extracts and lyophilized powders of Allium (garlic) species. CNPs were synthesized through ionotropic gelation and characterized by Z potential, hydrodynamic diameter (dynamic light scattering, DLS), and SEM. Aqueous garlic extracts were prepared via decoction. We assessed antimicrobial activity using disk diffusion and broth microdilution methods; in addition, a modified agar proportion method in blood agar was used for antimicrobial activity against MTB. CNPs inhibited MTB growth at 300 μg for 116.6 nm particles and 400 μg for 364.4 nm particles. The highest antimicrobial activity was observed against E. faecalis with nanoparticles between 200 and 280 nm. Allium sativum extract produced inhibition for C. albicans at 100 μg. The results indicate that CNPs possess significant antimicrobial properties against a range of pathogens, including MTB, at high concentrations. On the other hand, aqueous Allium sativum extracts exhibited antimicrobial activity. Nonetheless, due to their instability in solution, the use of lyophilized Allium sativum powder is preferable.

Study of Aerobic Bacteria from Surgical Site Infection and their Antibiotic Susceptibility Pattern at a Tertiary Care Centre in Eastern Nepal

Background: The surgical site infections are the third most common nosocomial infection. The most common organism is Staphylococcus aureus. Nepal has a 4-7% overall prevalence rate for surgical site infection. The study objective was to find out the aerobic bacteria from surgical site infection and their antibiotic susceptibility pattern in a tertiary care hospital in Nepal. Materials and Methods: A descriptive cross-sectional study was conducted at a tertiary care center with effect from September 2022 to September 2023 approval from the Institutional Review Committee. Pus samples were taken from the postoperative wound infection site and submitted to the microbiological laboratory for culture and sensitivity. Gram-positive aerobic bacteria and gram-negative aerobic bacteria were isolated and identified by standard microbiological procedures. An antimicrobial susceptibility test was done on Muller-Hinton agar using the Kirby Bauer disc diffusion method. The result was interpreted according to clinical and laboratory standard institute guidelines. Results: The rate of surgical site infection was 22.24% and the most common organisms isolated were Staphylococcus aureus followed by Escherichia coli and Pseudomonas aeruginosa. All the gram-positive cocci were sensitive to linezolid, teicoplanin, and vancomycin and gram-negative bacteria were sensitive to meropenem, piperacillin/tazobactam, cefoperazone/sulbactam and cefepime. Conclusion: The present study concluded that the most common aerobic bacteria isolated from surgical site infection in our setting was found to be Staphylococcus aureus. This study also showed that the gram-positive aerobic bacteria were most susceptible tolinezolid, and teicoplanin, and gram-negative aerobic bacteria were sensitive to meropenem, piperacillin/tazobactam, and cefoperazone/sulbactam.

Occurrence, virulence, and AMR profile of Vibrio parahaemolyticus isolated from shellfish growing areas located along the south-west coast of India.

Vibrio parahaemolyticus is a leading cause of human gastroenteritis associated with seafood consumption. The present study aimed to investigate the occurrence and risk assessment of V. parahaemolyticus isolated from live Indian black clams, sediment, and water samples collected from shellfish harvesting areas located along the south-west coast of India. Out of the total 72 samples collected, 55.6% revealed the presence of V. parahaemolyticus; the highest occurrence was observed in shellfish samples. The presence of tdh and trh virulence genes was screened by multiplex PCR. Virulence genes could be detected in 25.8% of the strains; 19.35% of them were trh positive and 3.2% were tdh positive, while 3.2% of strains exhibited the coexistence of both virulence genes. Antimicrobial resistance (AMR) determined by the disk diffusion method revealed that 87% of the strains were multiple drug resistant and exhibited 21 diverse resistance patterns. The overall multiple antibiotic resistance (MAR) index values ranged from 0 to 0.8. To the best of our knowledge, this is the first report to document the presence of pathogenic and multidrug-resistant V. parahaemolyticus in shellfish harvesting areas of the Indian sub-continent. The study reveals possible health hazards associated with consuming shellfish harvested from the study area.

Green synthesis of Bi2O3, MnO2 and their nanocomposite (Bi2O3/MnO2) for efficient photodegradation and antimicrobial activity

An eco-friendly green synthesis approach was used to synthesize Bi2O3, MnO2, and Bi2O3/MnO2 nanocomposite in order to comprehend the effect of nanocomposite on the photocatalytic and antibacterial activity. The structural parameters of as prepared samples were confirmed using X-ray diffraction analysis (XRD). Scherrer formula was applied to find out crystallite size, which ranged from 8 nm to 13 nm. XRD confirmed the geometrical structure of Bi2O3, MnO2 and Bi2O3/MnO2 nanocomposite showing monoclinic structure. The FTIR peaks also confirm the successful synthesis of Bi2O3/MnO2 nanocomposite. SEM of Bi2O3/MnO2 nanocomposite revealed that nanoparticles of Bi2O3 are developed on MnO2 granules. In UV–Vis spectroscopy, absorption maxima showed in the range of 200 nm to 400 nm and band gap ranging from 2.4 eV to 3.4 eV. The antibacterial activity of Bi2O3, MnO2, and Bi2O3/MnO2 nanocomposite was investigated against two gram negative-bacteria (Pseudomonas and Escherichia coli) at 10 mg and 20 mg concentration using disk diffusion method. The zone of inhibitions against Escherichia coli at 10 mg and 20mgl were 22 mm and 26 mm while against Pseudomonas were 28 mm and 33 mm for Bi2O3/MnO2 nanocomposite. Bi2O3/MnO2 composite shows better result as compared to Bi2O3 and MnO2. Photocatalytic activity was carried out using Bi2O3, MnO2, and Bi2O3/MnO2 as photocatalyst for the removal of malachite green (MG) and methylene blue (MB). For Malachite Green (MG), the maximum degradation efficiency of Bi2O3, MnO2, and Bi2O3/MnO2 nanocomposite was 96 %, 97 % and 98 % respectively. For methylene blue (MB), the maximum degradation efficiency of Bi2O3, MnO2, and Bi2O3/MnO2 nanocomposite was 95 %, 97 % and 98 % respectively. This work concludes that Bi2O3/MnO2 nanocomposite enhances the degradation efficiency and antibacterial potential.

Increasing Resistance of Nosocomial and Community-Acquired Escherichia coli in Clinical Samples from Hospitals and Clinics in Sana’a City

Antimicrobial resistance in Escherichia coli presents a global challenge associated with nosocomial infections and increased mortality rates. Understanding resistance profiles is crucial for guiding treatment strategies and ensuring effective antibiotic use. This study aimed to investigate the prevalence and in vitro resistance of E. coli to community-acquired and nosocomial infections. Various clinical samples from 700 patients were cultured on MacConkey’s medium and blood agar. The disk diffusion method was used to determine the antibiotic susceptibility profile of the E. coli isolates following the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Urine, pus, seminal fluid, vaginal swabs, and other body fluids were among the clinical samples analyzed. Of the 112 E. coli isolates, 48.2% were from inpatients and 51.8% were from outpatients, with the majority (66%) isolated from urine samples. Higher resistance levels were observed in the urinary isolates than that in the previously recorded data from the same institutions. Notably, isolates exhibited high resistance to penicillin (98.2%), ampicillin (97.3%), first-generation cephalosporins (90.2%), erythromycin (72.2%), and roxithromycin (95.4%), whereas lower resistance was noted against piperacillin-tazobactam (25.0%), nitrofurantoin (12.5%), and imipenem (9.8%). The overall multidrug resistance rate was 62.5%, with higher rates observed in nosocomial infections (70%) compared to community-acquired isolates (55.6%). However, this difference was not statistically significant (p>0.05). This study underscores the prevalence of E. coli isolates (27.0%) and highlights the concerning level of resistance, particularly to older antibiotics. These findings emphasize the importance of judicious antibiotic use and ongoing surveillance.

Poultry slaughterhouse wastewater as a source of bacterial antimicrobial resistance.

Slaughterhouses produce huge volumes of effluents throughout the production chain that, when discharged untreated into bodies of water, can become a source of environmental contamination. This is particularly worrisome if these effluents are used for irrigation since they increase contamination levels and spread pathogens and resistance determinants to humans and animals. Therefore, in this study, we assessed antimicrobial resistance in bacteria isolated from inlet water, equalization wastewater tanks, treatment plant wastewater, and treated wastewater in slaughterhouse facilities in Rio de Janeiro, Brazil. Four samples were collected at each of the collection points, between June 2021 and July 2022. Following bacterial isolation and identification, the samples were analyzed for antimicrobial resistance using the disk diffusion method to test aminoglycoside, beta-lactam, and fluoroquinolone antimicrobials. A total of 229 bacteria were isolated, with 74 isolates selected from the genera Citrobacter (12), Enterobacter (14), Klebsiella (35), Serratia (5), and Pseudomonas (8). Inlet water had the lowest number of isolates and was the only point with gentamicin-resistant isolates. Raw effluent from the equalization tank showed the highest number of isolated bacteria and resistance levels, followed by treated wastewater and the treatment plant. Across all samples, a high rate of cefoxitin-resistance was observed among the isolated bacteria. Klebsiella pneumoniae stood out as the species that demonstrated the greatest resistance to a variety of antimicrobials. These results highlight the importance of water quality monitoring in mitigating public health and environmental risks and high antimicrobial resistance levels.

Phenotypic patterns of antimicrobial resistance in Campylobacter spp. in Ukraine

Campylobacter spp. are major foodborne zoonotic pathogens that have recently become more resistant to fluoroquinolones and macrolides, which are broad-spectrum antibiotics used in both medicine and veterinary practice. Campylobacter is a commensal of the intestines of mammals and birds, which facilitates the transfer of antimicrobial resistance (AMR) determinants from other bacteria through horizontal gene transfer. The aim of this study was to establish the prevalence and determine the AMR phenotypes of Campylobacter species isolated in Ukraine. Using the disk diffusion method (DDM), 33 isolates of Campylobacter spp. isolated from animals and poultry on farms between May and September 2023 were tested. Additionally, an analysis of the resistance of 293 Campylobacter spp. isolates obtained from children with acute intestinal infections from 2020 to 2023 was conducted. The level of resistance of clinical Campylobacter spp. to ciprofloxacin (CIP) was found to be 83.3%, to tetracycline (TE) 53.6%, to erythromycin (E) 11.6%, and the isolates from farms showed resistance to ciprofloxacin (CIP) at 72.7%, to tetracycline (TE) at 60.6%, and to erythromycin (E) at 18.2%. In 4.1% of clinical isolates, multidrug resistance (MDR) (CIP/TE/E) was detected, with the most common AMR combination being (CIP/TE), reaching 42.7%. Resistance to at least one antibiotic was found in 37.8%. The isolates from animals and poultry had a multiple antibiotic resistance rate of 12.1%, with 42.4% being resistant to at least one antibiotic. This study provides insight into the relevance and importance of Campylobacter spp. resistance in Ukraine. It expands the understanding of the issue, which requires more detailed study, including the molecular mechanisms of resistance and the identification of genetic determinants shaping the epidemiology of antimicrobial resistance in Ukraine. For this purpose, a collection of isolates has been created, and optimal long-term storage conditions have been selected, which will allow the study of Campylobacter spp. decades from now.

Bacterial, fungal pathogens, and antimicrobial resistance patterns in ocular infections: Insights from a tertiary care hospital, North Karnataka

Background: Ocular infections, including conjunctivitis, keratitis, and endophthalmitis, significantly impact eye health, leading to morbidity, visual impairment, and blindness if not treated. Aims and Objectives: This study focuses on reviewing and analyzing the prevalence of bacterial and fungal pathogens in ocular infections and assessing their antimicrobial susceptibility patterns at Vijayanagar Institute of Medical Sciences, Ballari. Materials and Methods: A cross-sectional study was conducted by collecting ocular infection samples from January 01, 2022, to December 31, 2022. Samples, including corneal scrapings and conjunctival swabs, underwent initial procedures such as Gram staining and were inoculated on various agars. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disk diffusion method. Results: Out of 404 evaluated samples, corneal scrapings were predominant, with a significant incidence of fungal and bacterial growth. Aspergillus spp. and Pseudomonas spp. were the most common fungal and bacterial isolates, respectively. Antimicrobial susceptibility testing revealed that Gram-negative bacilli showed more susceptibility to gentamycin, ceftriaxone, and ciprofloxacin, whereas Gram-positive cocci were more susceptible to tetracycline and doxycycline. Conclusion: The study highlights the cornea as the most common source of ocular infections, with Aspergillus and Pseudomonas spp. being the predominant fungal and bacterial pathogens, respectively. Identifying the prevalent species in this geographical area aids in early diagnosis and treatment, thereby preventing morbidity and improving patient outcomes. The antimicrobial susceptibility pattern observed suggests effective options for treatment, emphasizing the need for ongoing surveillance to adapt to resistance patterns.

Molecular detection of extended-spectrum β-lactamase- and carbapenemase-producing Klebsiella pneumoniae isolates in southwest Iran.

The global emergence of carbapenem-resistant Klebsiella pneumoniae is considered a significant contemporary concern., as carbapenems are the last resort for treating infections caused by multidrug-resistant Gram-negative bacteria. This study aimed to investigate the carbapenem-resistance genes in extended-spectrum β-lactamase producing K. pneumoniae isolates. Seventy-five non-duplicate clinical K. pneumoniae strains were isolated from urine, blood, sputum, and wound samples. Antimicrobial susceptibility tests for 12 different antibiotics were performed using the disk diffusion method, followed by determining minimum inhibitory concentrations of imipenem and meropenem. Phenotypic detection of extended-spectrum β-lactamase and carbapenemase enzymes was performed by double-disc synergy test and modified Hodge test, respectively. PCR assay further investigated resistant isolates for extended-spectrum β-lactamase and carbapenemase-encoding genes. The highest and lowest resistance rates were observed against ampicillin (93.3%) and tigecycline (9.3%). According to phenotypic tests, 46.7% of isolates were positive for extended-spectrum β-lactamase enzymes and 52.8% for carbapenemase. A total of 11 isolates contained carbapenemase genes, with blaOXA-48 (19.4%; 7/36) being the predominant gene, followed by blaNDM (8.3%; 3/36). The study's findings reveal the alarming prevalence of beta-lactamase enzymes in K. pneumoniae strains. Early detection of carbapenem-resistant isolates and effective infection control measures are necessary to minimise further spread, as carbapenem resistance has become a public health concern.

Magnitude and antimicrobial susceptibility profile of bacteria isolated from pediatric sepsis cases at University of Gondar Hospital, Northwest Ethiopia

BackgroundSepsis is one of the major causes of morbidity and mortality among pediatric patients throughout the world. The varying microbiological pattern of sepsis warrants the need for researches on the causative organisms and their antimicrobial susceptibility pattern. The epidemiology of neonatal and pediatric sepsis in Ethiopia is under-research. The objective of this study was to evaluate the burden of bacterial pathogens and their antimicrobial susceptibility patterns among children suspected of sepsis.MethodsAn institutional-based prospective cross-sectional study was conducted on 370 pediatric(age birth-15 years) patients suspected of sepsis at the University of Gondar Comprehensive Specialized hospital from December 2020 to November 2021. Blood samples were collected aseptically and inoculated into Tryptone Soya Broth for culture. The organisms grown were identified by standard microbiological methods and subjected to antibiotic susceptibility testing by modified Kirby-Bauer disk diffusion method recommended by Clinical laboratory and standard institute. Methicillin resistance was confirmed using Cefoxitin disk diffusion method. Data entry and analysis were done using Statistical Package for Social Sciences (SPSS) version 26 software. A p-value less than 0.05 at 95% confidence interval was considered statically significant.ResultsOut of the total 370 study subjects, 21.6% (80/370) of them were culture positive. Of these, 43 (53.8%) and 37 (46.3%) were Gram-positive and Gram-negative bacterial pathogens, respectively. The most prevalent Gram-positive bacterial isolate was Staphylococcus aureus (n = 24; 30%) and coagulase negative staphylococci (n = 7; 8.8%). Among the Gram-negative bacterial isolates, the leading bacteria was Klebsiella pneumoniae (n = 20; 25%) followed by Escherichia coli (n = 7; 8.8%). Clindamycin, Chloramphenicol, Gentamicin and Ciprofloxacin were the most effective antibiotics against Gram-positive bacterial isolates while Amikacin, Meropenem and Chloramphenicol were effective against Gram-negative pathogens. Methicillin resistance was detected in 45.8% of Staphylococcus aureus. Multi-drug resistance (MDR) antimicrobial susceptibility pattern was observed in 76% of the bacterial isolates.ConclusionGram positive bacteria were the predominant isolates among pediatric sepsis cases and most of the bacterial isolates showed MDR. Staphylococcus aureus and Klebsiella pneumoniae were frequently isolated bacteria. The high prevalence of drug resistance warrants rational use of antibiotics and the need for regular antibiotic susceptibility surveillance studies.

Facile biosynthesis of zinc oxide nanoparticles (ZnO NPs) using Lupinus albus L (Gibto) seed extract for antibacterial and photocatalytic applications

This study aimed to synthesize zinc oxide nanoparticles (ZnO NPs) from Lupinus albus L. (white lupin) seed extract and investigate their photocatalytic and antibacterial applications. Phytochemical analysis of the seed extract revealed the presence of flavonoids, polysaccharides, alkaloids, and phenolic compounds. Three ZnO NP samples were prepared using different ratios of the seed extract and zinc nitrate and one sample without seed extract as a control. The nanoparticles were characterized using various techniques, and the average crystallite sizes were found to be in the range of 20.96–30.67 nm, exhibiting a hexagonal wurtzite structure. The photo catalytic activity of the ZnO NPs was evaluated by the degradation of malachite green dye under visible light. The results showed that ZnO NPs synthesized with the seed extract, particularly the 9:1 and 3:2 ratios, exhibited higher photocatalytic activity, with degradation efficiencies of 98 % and 97 %, respectively, compared to the ZnO NPs prepared without the extract (89 % degradation). The antibacterial activity of the ZnO NPs was assessed against four bacterial strains using the disc diffusion method. The ZnO NPs synthesized with the seed extract demonstrated the greatest activity against Klebsiella pneumonia, with an inhibition zone of 15 ± 0.58 mm, while the ZnO NPs without the extract showed lower antibacterial activity. In conclusion, the green synthesis of ZnO NPs using Lupinus albus L. seed extract is a promising approach for the development of materials with efficient photocatalytic and antibacterial properties.

Modulation of dielectric and antibacterial properties of Zn0.5Mn0.5O nanoparticles by post growth annealing method

In this manuscript, we have investigated the dielectric and antibacterial potential of hydrothermally synthesized ZnMnO nanoparticles. The synthesized nanoparticles were annealed at various temperatures ranging from 450 to 650 °C with a step of 50 °C to modulate the structural, vibrational, dielectric, and antibacterial properties. XRD data confirmed the hexagonal structure of the synthesized samples and crystalline size was decreased to 4.8 nm at annealing temperature 600 °C. The lattice structure was further verified by Raman spectroscopy measurements, which strongly verified the XRD data due the presence of ZnMnO vibrational modes. The dielectric measurements revealed that the dielectric constant and los tangent were found to be increased with the increase annealing temperature and decreased with frequency, while a.c conductivity has an increasing trend with both parameters (temperature and frequency). The plot of real and complex parts of impedance against frequency demonstrated that both parameters decrease with the increased in frequency. But when we analyzed the behavior of the real part of impedance against the annealing temperature, a degradation in real part behavior is observed. The antibacterial activity of ZnMnO nanoparticles was determined by using the disc diffusion method against E. coli bacteria, which was grown on a Petri dish at room temperature for 24 h. This observation revealed that the samples annealed at 450 °C and 550 °C show remarkable antibacterial sensitivity as compared to other samples. It is concluded that crystalline size of 20 nm is found to be optimal value for good anti-baterial behavior.

From Ficus recemosa Leaf Galls to Therapeutic Silver Nanoparticles: Antibacterial and Anticancer Applications.

The synthesis of silver nanoparticles (AgNPs) using environmentally friendly methods has become increasingly important due to its sustainability and cost-effectiveness. This study investigates the green synthesis of AgNPs using gall extracts from the plant Ficus recemosa, known for its high phytochemical content. The formation of AgNPs was verified through multiple analytical techniques, including UV-Vis spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), zeta potential analysis, and dynamic light scattering (DLS). The UV-Vis spectroscopy results displayed a distinct surface plasmon resonance peak indicative of AgNP formation. FTIR analysis revealed specific interactions between silver ions and phytochemicals in the gall extract, while TEM images confirmed the nanoscale morphology and size of the synthesized particles. Zeta potential and DLS analyses provided insights into the stability and size distribution of the AgNPs, demonstrating good colloidal stability. Biological properties of the AgNPs were assessed through various assays. Antimicrobial activity was tested using the disc diffusion method against Escherichia coli and Staphylococcus aureus, showing significant inhibitory effects. The anticancer potential was evaluated using the trypan blue exclusion assay on Dalton's Lymphoma Ascites (DLA) cells, revealing considerable cytotoxicity. Additionally, antimitotic activity was studied in the dividing root cells of Allium cepa, where the AgNPs significantly inhibited cell division. This research highlights the effective use of F. recemosa gall extracts for the green synthesis of AgNPs, presenting an eco-friendly approach to producing nanoparticles with strong antimicrobial, anticancer, and antimitotic properties. The promising results suggest potential applications of these biogenic AgNPs in medical and agricultural sectors, paving the way for further exploration and utilization.