Modified Disc Diffusion Method Research Articles

Abietic Acid as a Novel Agent against Ocular Biofilms: An In Vitro and Preliminary In Vivo Investigation.

Biofilm-related ocular infections can lead to vision loss and are difficult to treat with antibiotics due to challenges with application and increasing microbial resistance. In turn, the design and testing of new synthetic drugs is a time- and cost-consuming process. Therefore, in this work, for the first time, we assessed the in vitro efficacy of the plant-based abietic acid molecule, both alone and when introduced to a polymeric cellulose carrier, against biofilms formed by Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans in standard laboratory settings as well as in a self-designed setting using the topologically challenging surface of the artificial eye. These analyses were performed using the standard microdilution method, the biofilm-oriented antiseptic test (BOAT), a modified disk-diffusion method, and eyeball models. Additionally, we assessed the cytotoxicity of abietic acid against eukaryotic cell lines and its anti-staphylococcal efficacy in an in vivo model using Galleria mellonella larvae. We found that abietic acid was more effective against Staphylococcus than Pseudomonas (from two to four times, depending on the test applied) and that it was generally more effective against the tested bacteria (up to four times) than against the fungus C. albicans at concentrations non-cytotoxic to the eukaryotic cell lines and to G. mellonella (256 and 512 µg/mL, respectively). In the in vivo infection model, abietic acid effectively prevented the spread of staphylococcus throughout the larvae organisms, decreasing their lethality by up to 50%. These initial results obtained indicate promising features of abietic acid, which may potentially be applied to treat ocular infections caused by pathogenic biofilms, with higher efficiency manifested against bacterial than fungal biofilms.

Antibacterial copper-filled TiO2 coating of cardiovascular implants to prevent infective endocarditis-A pilot study.

Infective endocarditis (IE) poses a significant health risk, especially in patients with prosthetic heart valves. Despite advances in treatment, mortality rates remain high. This study aims to investigate the antibacterial properties of a copper titanium dioxide (4× Cu-TiO2) coating on cardiovascular implants against Staphylococcus aureus, a common causative agent of IE. Titanium oxide carriers functionalized with copper ions were employed as an antibacterial coating for heart and vascular prostheses. The coating's antibacterial efficacy was assessed using S. aureus ATCC 29213. Microscopic evaluations were conducted on both biological and artificial materials. Antibacterial activity was qualitatively assessed via a modified disc diffusion method and quantitatively measured through colony counts in NaCl suspensions. The coating process was successfully applied to all tested cardiovascular prosthetic materials. Qualitative assessments of antibacterial effectiveness revealed an absence of bacterial growth in the area directly beneath the coated valve. Quantitative evaluations showed a significant reduction in bacterial colonization on coated mechanical valves, with 2.95 × 104 CFU per valve, compared to 1.91 × 105 CFU in control valves. The 4× Cu-TiO2 coating demonstrated promising antibacterial properties against S. aureus, suggesting its potential as an effective strategy for reducing the risk of bacterial colonization of cardiovascular implants. Further studies are needed to assess the longevity of the coating and its efficacy against other pathogens.

Co-expression of four penaeidins in transgenic rice seeds: an alternative strategy for substitute antibiotic agricultural products.

The co-expression of multiple antimicrobial peptides (AMPs) in genetically modified (GM) crops can give plants a broader antibacterial spectrum and lower the pathogen risk of drug resistance. Therefore, four penaeidins (shrimp-derived AMPs) were fused and encoded in an artificial gene (PEN1234), driven by the seed-specific promoter Pzein, with the aim of co-expression in seeds of transgenic rice. The resistant rice plants, acquired via Agrobacterium-mediated transformation and glufosinate screening, were identified by PCR and the modified disk-diffusion method, and eight GM lines with high AMP content in the seeds were obtained. Among them, the PenOs017 line had the largest penaeidin content, at approximately 251-300μg/g in seeds and 15-47μg/g in roots and leaves. The AMPs in the seeds kept their antibacterial properties even after the seed had been boiled in hot water and could significantly inhibit the growth of methicillin-resistant Staphylococcus aureus, and AMPs in the leaves could effectively inhibit Xanthomonas oryzae pv. Oryzae. The results indicate that PenOs017 seeds containing AMPs are an ideal raw-material candidate for antibiotic-free food and feed, and may require fewer petrochemical fungicides or bactericides for disease control during cultivation than conventional rice.

Antibiotic Profiles of Enteric Pathogens Isolated from Nigerian Currency Notes

Background: Currency notes are exchangeable fomites handled by many persons daily and can potentially carry enteric pathogens on their surfaces. Infections caused by these pathogens have a global impact on public health. This study aimed to analyse the Nigerian currency notes Naira for the presence of enteric bacteria, particularly drug-resistant strains. Methods: Sixty-four Nigerian currency notes were randomly collected from various sources. Using the spread plate technique, an aliquot of 0.1ml of 10-6 dilution of each sample suspension was inoculated onto Eosin Methylene Blue agar and Hektoen Enteric agar plates. Following incubation, colonies were counted and recorded in colony-forming units per milliliter, and morphologic features were observed. Bacterial isolates were then Gram-stained, tested for motility and characterized using standard biochemical techniques. Antimicrobial profiles of bacterial isolates were determined using the Kirby-Bauer modified disc diffusion method. Results: Preliminary analysis showed that 67.2% of currency notes were contaminated. The 100 Naira notes had the highest contamination rates with bacterial mean counts of 1.22×1010 cfu/ml. Three different species of enteric bacteria were isolated. The predominant pathogens were Escherichia coli (44.2%) and Salmonella spp. (44.2%). All isolates recovered were 100% susceptible to amikacin, gentamicin, and ciprofloxacin, while 97.7% were resistant to penicillin. Escherichia coli was resistant to ampicillin (100%) and trime-thoprim-sulfamethoxazole (89.5%). Conclusion: This study showed that the Nigerian currency notes harbour enteric pathogens capable of causing serious infections to handlers. Therefore, improved hygiene practices, especially after handling currency notes, should be encouraged to prevent the spread of these pathogens.

Antibiogram And Prevalence Of ESBL Genes In Escherichia Coli From Clinical Specimen

The members of the Enterobacteriaceae family are among the most common causative agents of various clinical infections. Some pathogens produce enzymes to escape the effect of antibiotics and the ESBL enzyme is the new strategy of the bacterial pathogen which is responsible for emerging antimicrobial resistance. The prevalence of Gram Negative bacteria that are usually associated with the production of ESBLs enzymes is on the rise around the globe, both in residing area and hospital setups, as a result, multiple therapeutic problems including antibiotic resistance are being faced. The current study was aimed to look at the characteristics, the pattern of antibiotic resistance, and to estimate the prevalence of ESBL-producing Escherichia coli in clinical isolates. The samples after collection were streaked and cultured on MacConkey, and chocolate, and blood agar. The identification of the isolates was done based on various biochemical characteristics, and the API 20-E test. The modified Disc Diffusion method was used to confirm ESBL enzyme synthesis, and the Kirby Bauer disc diffusion method was used to assess antibiotic susceptibility. Out of 121 isolates of E. coli, 51.2% (n=62) were recovered from female patients and 48.8% (n=59) were obtained from male patients. The genotypic detection of ESBL genes was done by PCR followed by gel electrophoresis. Of total 47 E. coli confirmed for the production of ESBLs, 91.4% (n=43) were found harbouring blaCTX-M followed by blaTEM and blaSHV with 21.2% (n=10) and 8.5% (n=4) prevalence. The table gives an overview of ESBL gene distribution in clinically isolated E. coli. The current study indicates the magnitude of antimicrobial resistance and the underlying genes especially the blaCTX-M gene among the E. coli isolates.

Antibiotic Resistance and Sensitivity Pattern of Pseudomonas aeruginosa Obtained from Clinical Samples

This study aimed to determine the antibiotic susceptibility profile of Pseudomonas aeruginosa from fifty different isolates of varied clinical origins. A total of 700 samples of pus, urine, swab, and other samples from various patients were examined. Based on bacterial growth over routine nutrient agar and MacConkey medium, isolates with positive results on both media were chosen. Using the modified disc-diffusion method (Modified-Kirby Baur method), antimicrobial sensitivity of total isolates was operated by following CLSIs guidelines. In the current study, a large number of isolates of P. aeruginosa obtained from different specimens are resistant to Cefixime (82%), followed by Ampicillin (79%) and Augmentin (61%). However, the antibiogram of P. aeruginosa also showed that most of the isolates (86%) were highly sensitive to Amikacin. The second maximum sensitivity of P. aeruginosa was seen towards Tazocin (80%), followed by Tecarcilline (79%). P. aeruginosa offers a high risk of antibiotic resistance to a wide range of antibiotics; hence it is necessary to avoid the use of antibiotics to reduce antibiotic resistance. Also, researchers should search for the discovery of certain novel antibiotics that may provide impressive inhibition toward Pseudomonas aeruginosa.

Enhanced photocatalytic and Antibacterial Activity of Copper oxide Nanoparticles Synthesized by Facile Combustion methods from Mussaendafrondosa Plant Extract

Microwave heating (MHM) and mutated sol-gel (SGM) mechanisms were used to effectively create CuO samples with two dissimilar morphologies, such as nanoparticles (CuO-NPs) and nanorods (CuO-NRs), using Mussaendafrondosalinn plant extract as the bio-reducing operator. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) investigations were used to analyze the sample's structure, pureness, and morphological characteristics. UV-Visible diffuse reflectance (DRS) and photoluminescence (PL) spectroscopy methodologies were used to analyze optical properties and calculate bandgap energy. The bandgap of the samples was measured using the Kubelka-Munk mechanism, and it was found to be 2.74eV and 2.33eV for CuO-NPs and CuO-NRs, correspondingly. CuO-NPs and CuO-NRs were investigated for antibacterial activity versus each Gram-positive and Gram-negative microorganisms using a modified disc diffusion method. When correlated to the sample CuO nanorods, the antibacterial study confirms that the sample CuO nanoparticles are high-grade antibacterial agents. Using solar lighting, the photocatalytic activity of CuO nano-reactants (CuO-NPs and CuO-NRs) for the degradation of methylene blue (MB) dye was investigated, and the findings revealed that CuO-NPs with tinier particle sizes degraded MB more than CuONRs.

In Vitro Cytotoxicity, Colonisation by Fibroblasts and Antimicrobial Properties of Surgical Meshes Coated with Bacterial Cellulose.

Hernia repairs are the most common abdominal wall elective procedures performed by general surgeons. Hernia-related postoperative infective complications occur with 10% frequency. To counteract the risk of infection emergence, the development of effective, biocompatible and antimicrobial mesh adjuvants is required. Therefore, the aim of our in vitro investigation was to evaluate the suitability of bacterial cellulose (BC) polymer coupled with gentamicin (GM) antibiotic as an absorbent layer of surgical mesh. Our research included the assessment of GM-BC-modified meshes’ cytotoxicity against fibroblasts ATCC CCL-1 and a 60-day duration cell colonisation measurement. The obtained results showed no cytotoxic effect of modified meshes. The quantified fibroblast cells levels resembled a bimodal distribution depending on the time of culturing and the type of mesh applied. The measured GM minimal inhibitory concentration was 0.47 µg/mL. Results obtained in the modified disc-diffusion method showed that GM-BC-modified meshes inhibited bacterial growth more effectively than non-coated meshes. The results of our study indicate that BC-modified hernia meshes, fortified with appropriate antimicrobial, may be applied as effective implants in hernia surgery, preventing risk of infection occurrence and providing a high level of biocompatibility with regard to fibroblast cells.

Investigation the Antimicrobial Activity of Methanol Extracts of the Leaves of Ficus Nitida

The aim of this study was to prepare crude extracts from the leaves of Ficus nitida and determine their content as well as their antimicrobial activity. Powdered leaf samples were extracted with methanol by using maceration method. The resulting crude extract was suspended in water and successively extracted with petroleum ether, chloroform, ethyl acetate and methanol solvents respectively. Total flavonoids of the above extracts were determined by the aluminum chloride method and antimicrobial activity of the same extracts was assessed by a slightly modified disc diffusion method against different gram positive and gram negative bacterial strains. The highest flavonoids content was found in chloroform crude extract followed by that of petroleum ether, ethyl acetate and methanol extracts respectively. Tested against four bacterial strains, the extracts showed activity in the range of 0-12 mm, using amoxicillin as standard. The present findings could establish this plant as a potential source of antibiotics.

Formulation and Evaluation of Gel Containing Anthocyanin of Punica Granatum L. Extract for Anti-Inflammatory and Anti-Microbial Activity

Aim The study aimed to formulate and evaluate gel containing anthocyanin extract and to study its anti-inflammatory and anti-microbial activity.Methodology Anthocyanin was extracted from Punica granatum L. by placing fresh arils in methanol containing 1 HCl vv by maceration method for 24h. Anthocyanin gels were formulated using various polymers like xanthan gum Carbopol-940 HPMC K100M and Sodium CMC. Formulated gels were subjected to compatibility studies by ATR pH viscosity spreadability extrudability and in-vitro drug release. The best formulations were evaluated for antimicrobial activity which was carried out by the modified disk diffusion method and anti-inflammatory activity by the rat paw edema method.Results Compatibility studies revealed no interaction of anthocyanin concentrate with the excipients. Formulated gels had a pH similar to skin. Gels prepared using Sodium CMC were less viscous and showed good spreadability and excellent extrudability compared to other formulations. Formulation F7 showed the best result when compared with the marketed diclofenac gel for anti-inflammatory activity. Both gram-positive and gram-negative bacteria were inhibited by anthocyanin concentrate gels. F7 was found to have a substantial anti-inflammatory effect among prepared gels containing anthocyanin concentrate..Conclusion Anthocyanin extract of Punica granatum L. gel can be utilized to reduce inflammation and can be used to prevent the growth of microorganisms.nbsp

Copper crosslinked carboxymethyl chitosan–gelatin scaffolds: A potential antibacterial and cytocompatible material for biomedical applications

The study delineates the development and characterization of carboxymethyl chitosan–gelatin-copper oxide (CuO) crosslinked scaffolds for biomedical applications. Four scaffolds were developed using lyophilization technique using two stage crosslinking and evaluated using FT-IR, TGA to ascertain the crosslinking. Further, swelling index (SI), hydrolytic degradation, water vapour transmission rate (WVTR) as well as morphological characterization of scaffolds were carried out using SEM and optical profilometer. Additionally, modified disc diffusion method and MTT assay was carried out to check antibacterial action and cyto-compatibility. The results revealed that SI, hydrolytic degradation, and WVTR changes with the change in percentage of CuO. Further, effect of CuO concentration was evident from roughness variations of the developed scaffolds. Additionally SEM images shows presence of micro pores and the scaffolds exhibited good antibacterial action both against Gram positive and Gram negative bacteria. Lastly cytotoxicity assay exhibited good cell viability even at higher concentration of CuO nanoparticles. Thus, this work represents a facile approach to develop CuO crosslinked scaffolds of CMCh-gelatin that may potentially be explored further for biomedical applications.

Clinical Specimens are the Pool of Multidrug- resistant Pseudomonas aeruginosa Harbouring oprL and toxA Virulence Genes: Findings from a Tertiary Hospital of Nepal.

The multidrug- or extensively drug-resistant (MDR/XDR) Pseudomonas aeruginosa carrying some virulence genes has become a global public health threat. However, in Nepal, there is no existing report showing the prevalence of oprL and toxA virulence genes among the clinical isolates of P. aeruginosa. Therefore, this study was conducted for the first time in the country to detect the virulence genes (oprL and toxA) and antibiotic susceptibility pattern of P. aeruginosa. A total of 7,898 clinical specimens were investigated following the standard microbiological procedures. The antibiotic susceptibility testing was examined by the modified disc diffusion method, and virulence genes oprL and toxA of P. aeruginosa were assessed using multiplex PCR. Among the analyzed specimens, 87 isolates were identified to be P. aeruginosa of which 38 (43.68%) isolates were reported as MDR. A higher ratio of P. aeruginosa was detected from urine samples 40 (45.98%), outpatients' specimens 63 (72.4%), and in patients of the age group of 60–79 years 36 (41.37%). P. aeruginosa was more prevalent in males 56 (64.36%) than in female patients 31 (35.63%). Polymyxin (83.90%) was the most effective antibiotic. P. aeruginosa (100%) isolates harboured the oprL gene, while 95.4% of isolates were positive for the toxA gene. Identification of virulence genes such as oprL and toxA carrying isolates along with the multidrug resistance warrants the need for strategic interventions to prevent the emergence and spread of antimicrobial resistance (AMR). The findings could assist in increasing awareness about antibiotic resistance and suggest the judicious prescription of antibiotics to treat the patients in clinical settings of Nepal.

Characterization of Tigecycline-Heteroresistant Klebsiella pneumoniae Clinical Isolates From a Chinese Tertiary Care Teaching Hospital.

Tigecycline has been used as one of the therapeutic choices for the treatment of infections caused by multidrug-resistant Klebsiella pneumoniae. However, the emergence of tigecycline heteroresistance has led to great challenges in treating these infections. The purpose of this study was to investigate whether tigecycline-heteroresistant K. pneumoniae (TGCHR-Kp) exists in clinical isolates, and to further characterize the underlying molecular mechanisms involved in the development of tigecycline-resistant subpopulations. Of the 268 tigecycline-susceptible clinical K. pneumoniae isolates, 69 isolates were selected as tigecycline-heteroresistant candidates in the preliminary heteroresistant phenotypic selection by a modified disk diffusion method, and only 21 strains were confirmed as TGCHR-Kp by the population analysis profile (PAP). Pulsed-field gel electrophoresis (PFGE) analysis demonstrated that all the parental TGCHR-Kp isolates were clonally unrelated, and colonies confirmed as the heteroresistant subpopulation showed no significant differences from their respective parental TGCHR-Kp isolates. Efflux pump inhibitors reversed the tigecycline susceptibility in heteroresistant subpopulations. Mutations in the ramR and soxR genes lead to upregulation of the ramA and soxS transcriptional regulators, which in turn induced overexpression of the AcrAB-TolC efflux pump genes in TGCHR-Kps-resistant subpopulations. Moreover, mutations of rpsJ were also found in resistant subpopulations, which suggested that the rpsJ mutation may also lead to tigecycline resistance. Time-kill assays showed that the efficacy of tigecycline against TGCHR-Kps was weakened, whereas the number of resistant subpopulations was enriched by the presence of tigecycline. Our findings imply that the presence of TGCHR-Kps in clinical strains causes severe challenges for tigecycline therapy in clinical practice.

МИКРОБИОЛОГИЧЕСКАЯ ЭФФЕКТИВНОСТЬ КОМБИНАЦИЙ АНТИБИОТИКОВ В ОТНОШЕНИИ ИНВАЗИВНЫХ ШТАММОВ KLEBSIELLA PNEUMONIAE

Background. Combined antibiotic therapy is the main treatment for infections caused by antibiotic-resistant bacteria. The aim of this research was to identify the synergistic activity of antibiotic combinations against invasive extensively drug-resistant K. pneumoniae strains producing carbapenemases. Material and methods. For 12 invasive KPC-, OXA-48- and NDM-producing K. pneumoniae strains, the minimum inhibiting concentrations of antibiotics were determined. The susceptibility to antibiotic combinations was determined using the modified disk diffusion method. Results. The effect of potentiating the activity of colistin with aztreonam (58.3% of strains), azithromycin (33.3%), clarithromycin (41.7%), rifampicin (33.3%) as well as doxycycline (50%) was noted. High microbiological efficiency of ceftazidime/avibactam against all producers of KPC and OXA-48-carbapenemases was demonstrated. For MBLNDM-producing strains, a synergistic effect of the combination of ceftazidime/avibactam and aztreonam with restoration of susceptibility was revealed. Conclusion. The obtained findings open up perspectives for combination therapy of bloodstream infections caused by XDR-strains of K. pneumoniae.

In Vitro Efficacy of Bacterial Cellulose Dressings Chemisorbed with Antiseptics against Biofilm Formed by Pathogens Isolated from Chronic Wounds.

Local administration of antiseptics is required to prevent and fight against biofilm-based infections of chronic wounds. One of the methods used for delivering antiseptics to infected wounds is the application of dressings chemisorbed with antimicrobials. Dressings made of bacterial cellulose (BC) display several features, making them suitable for such a purpose. This work aimed to compare the activity of commonly used antiseptic molecules: octenidine, polyhexanide, povidone-iodine, chlorhexidine, ethacridine lactate, and hypochlorous solutions and to evaluate their usefulness as active substances of BC dressings against 48 bacterial strains (8 species) and 6 yeast strains (1 species). A silver dressing was applied as a control material of proven antimicrobial activity. The methodology applied included the assessment of minimal inhibitory concentrations (MIC) and minimal biofilm eradication concentration (MBEC), the modified disc-diffusion method, and the modified antibiofilm dressing activity measurement (A.D.A.M.) method. While in 96-well plate-based methods (MIC and MBEC assessment), the highest antimicrobial activity was recorded for chlorhexidine, in the modified disc-diffusion method and in the modified A.D.A.M test, povidone-iodine performed the best. In an in vitro setting simulating chronic wound conditions, BC dressings chemisorbed with polyhexanide, octenidine, or povidone-iodine displayed a similar or even higher antibiofilm activity than the control dressing containing silver molecules. If translated into clinical conditions, the obtained results suggest high applicability of BC dressings chemisorbed with antiseptics to eradicate biofilm from chronic wounds.

Antibiotic Resistance and Phenotypic and Genotypic Detection of Colistin Resistance among Enterobacter Species Isolated from Patients of a Tertiary Care Hospital, Bangladesh

The prevalence of antimicrobial resistance among Enterobacter species is alarmingly high. Colistin as a last resort antibiotic reintroduced in the treatment pipeline to combat the drug resistant Enterobacter infection has led to emergence of colistin resistance. The study was designed to determine the prevalence of antibiotic resistance among isolated Enterobacter and to assess the occurrence of colistin resistance both phenotypically and genotypically in a tertiary care hospital, Bangladesh. This cross-sectional study was conducted during the period July2018 to June 2019. A total 350 different samples were processed. Enterobacter were identified phenotypically and were processed for antimicrobial susceptibility test (AST) by using modified disk diffusion method. Colistin resistance was determined by minimum inhibitory concentration (MIC) using agar dilution method. Colistin resistant strains were further processed for colistin resistance genes using polymerase chain rection (PCR). Among the total samples processed, 65.14% (228/350) yielded culture positive growth of which 12.28% (28/228) were Enterobacter species. Among isolated Enterobacter 22 (9.64%) were E. cloacae and 6 (2.63%) were E. aerogenes. In AST, 89.29%, 57.14% and 42.86% were resistant to ciprofloxacin, amikacin and imipenem respectively. Tigecycline and colistin were most effective antibiotics. Among colistin resistant Enterobacter isolates, 85.71%, 71.42%, 42.85% and 57.14% were positive for PmrC, PmrA, PhoP and PmrB respectively detected by PCR. Our study reports identification and distribution of drug resistant Enterobacter strains in a major tertiary care hospital. High prevalence of drug resistance and emergence of colistin resistance is indicative of deteriorating situation. Therefore, further extensive surveillance is mandatory.

Investigation of antibacterial and photocatalytic efficiency of green ZnO nanoparticles that synthesized with Celosia Cristata flower extract.

Increasing interest in green chemistry has led scientists to an environmentally friendly nanoparticle synthesis approach that has many advantages, such as simple, affordable and versatility for a wide range of commercial production. In this study, green synthesis of zinc oxide nanoparticles (ZnO NPs), which is widely researched in the field of nanotechnology, was performed under different conditions (volume ratio of CC flower extract to Zn(CH3COO)2 solution, time, pH and temperature) using the aqueous extract of Amarant (Celosia cristata L., CC, cockscome) plant flowers. Produced ZnO NPs were characterized by UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HR-TEM) and scanning electron microscopy (SEM) analysis. The characteristic absorption peak seen at λmax: 364 nm in the UV-Vis absorption spectrum and the band seen at 381 cm-1 in the FTIR spectrum indicate that ZnO NPs were synthesized. TEM image also confirmed the formation of nanoparticles. The average size of nanoparticles is approximately 22-27 nm and the shape of the ZnO NPs as nearly spherical. The effect of different calcination temperatures (100, 200, 300, 400, and 500 °C) on the size of ZnO NPs was investigated and it was observed that the particle size decreased as the calcination temperature increased. ZnO NPs were also used as photo catalyst for removal of basic yellow28 (BY28) and basic violet39 (BV39) dyestuffs which are used in textile industry and ecologically toxic. The decolorization efficiency was found 95%-100% and 62% respectively when the BV39 and BY28 dyestuffs were exposed to UV light for 160 min. Antibacterial activity of ZnO NPs produced with different amounts of CC flower extract and calcined at different temperatures (100, 200, 300, 400, and 500 °C) was investigated using modified disc diffusion method. Produced ZnO NPs displayed antibacterial activity against Staphylococcus aureus and Escherichia coli bacterial strains and were more effective against gram-positive pathogens. The findings displayed that the antibacterial activity of ZnO NPs is related to the particle size. This new environmentally friendly synthesis approach is a suitable technique for large-scale commercial production and can be considered as an alternative to chemical methods.

Potential of Bacterial Cellulose Chemisorbed with Anti-Metabolites, 3-Bromopyruvate or Sertraline, to Fight against Helicobacter pylori Lawn Biofilm.

Helicobacter pylori is a bacterium known mainly of its ability to cause persistent inflammations of the human stomach, resulting in peptic ulcer diseases and gastric cancers. Continuous exposure of this bacterium to antibiotics has resulted in high detection of multidrug-resistant strains and difficulties in obtaining a therapeutic effect. The purpose of the present study was to determine the usability of bacterial cellulose (BC) chemisorbed with 3-bromopyruvate (3-BP) or sertraline (SER) to act against lawn H. pylori biofilms. The characterization of BC carriers was made using a N2 adsorption/desorption analysis, tensile strength test, and scanning electron microscopy (SEM) observations. Determination of an antimicrobial activity was performed using a modified disk-diffusion method and a self-designed method of testing antibacterial activity against biofilm microbial forms. In addition, bacterial morphology was checked by SEM. It was found that BC disks were characterized by a high cross-linking and shear/stretch resistance. Growth inhibition zones for BC disks chemisorbed with 2 mg of SER or 3-BP were equal to 26.5–27.5 mm and 27–30 mm, respectively. The viability of lawn biofilm H. pylori cells after a 4-h incubation with 2 mg SER or 3-BP chemisorbed on BC disks was ≥4 log lower, suggesting their antibacterial effect. SEM observations showed a number of morphostructural changes in H. pylori cells exposed to these substances. Concluding, SER and 3-BP chemisorbed on BC carriers presented a promising antibacterial activity against biofilm H. pylori cells in in vitro conditions.

UJI SITOTOKSIK DAN AKTIVITAS ANTIBAKTERI EKSTRAK DAUN PANDAN LAUT (Pandanus Odorifer) TERHADAP BAKTERI Staphylococcus aureus

This study aims to determine the activity of marine pandanus extract(Pandanus odorifer) as cytotoxic and antibacterial to Staphylococcus aureus bacteria. This research begins with phytochemical test conducted to find out the secondary metabolite compounds contained in the leaves of P. odorifer. Cytotoxic testing was performed using BSLT method. An antibacterial test was performed against the activity in inhibiting the growth of S. aureus bacteria using a modified disc diffusion method. The results of phytochemical tests showed that ethanol extract of pandanus leaves contain saponin, flavonoids, tannin and terpenoid compounds. The results of cytotoxic test of sea pandan have a very strong toxic level with LC50 value of 4.3557 ppm.The result of measurement of the highest inhibiting zone diameter was obtained at the concentration of 5x104 ppm is 6 mm with the power of inhibitory that is medium. Based on the results of this study can be concluded that the leaves of sea pandan are cytotoxic and have activity as antibacterial

Etiological Profile and Antimicrobial Patterns in Blood Culture Specimens in a Tertiary Care Setting.

IntroductionUniversally, blood stream infections are linked with increasing morbidity and mortality. Timely diagnosis for identification of bacterial etiology, their susceptibility pattern and choice of empiric treatment plays a vital role in management.ObjectiveTo reveal the etiological profile and antibiotic sensitivity in blood culture specimens in a tertiary care setting.MethodsThis descriptive study was carried out in pathology laboratory of a tertiary care hospital from August 2016 to July 2019. All the 750 blood culture bottles were processed and isolates were recognized by morphological appearance on recommended media, gram stain, and different biochemical tests using Analytic Profile Index. Antibiotic sensitivity was implemented by modified disc diffusion method as per Clinical and Laboratory Standards Institute (CLSI) principles (2019).ResultsOut of 750 blood samples, 212 (28.26%) were culture positive. The percentage of gram-negative bacilli (n = 105) and gram-positive cocci (n = 104) was almost same (49.52%), while candida spp. was recovered from three (1.41%) isolates. The identified gram-negative bacteria were E. coli and Acinetobacter baumannii each (19.04%), Klebsiella pneumoniae and Pseudomonas aeruginosa each (16.19%), Enterobacter cloaca (11.42%), Salmonella typhi (8.57%), Burkholderia cepacia (1.90%), and Raoultella terrigena (7.61%). Among gram-positive isolates, coagulase-negative staphylococci (79.80%), Staphylococcus aureus (6.73%), Enterococcus spp. (11.53%) and Streptococcus spp. (1.92%) were recovered. Colistin, imipenem, meropenem, and amikacin were most successful against gram-negative rods. The sensitivity to vancomycin, teicoplanin and linezolid was 100%, for gram positive organisms. Methicillin resistance was present in 84.4% Staphylococcal isolates.ConclusionLocal data showing changing etiological pattern and antibiogram of isolated pathogens, along with adequate infection prevention and control measures can be useful to improve patient care, in terms of hospital stay, duration of medication and treatment cost.