Dilution Test Methods Research Articles

Evaluation of the anti-bacterial activity of aqueous leaf extract of Phyllanthus amarus on Streptococcus pyogenes for the treatment of tonsillitis

Phyllanthus amarus belongs to the Euphorbiaceae family, it is a tiny herb that is known for its medical benefits and used widely globally. It is also an essential plant in the Indian Ayurveda medical system, and is used to treat stomach, genitourinary, liver and kidney problems and disorders. It is an astringent with bitter, stomachic, diuretic, febrifuge, and antiseptic in gonorrhea, menorrhagia, and other genital disorders, the entire plant is employed in eastern Asia for the treatment of infections. It helps with gastritis, diarrhea, dysentery, intermittent fevers, scabies, ulcers, and wounds. The present study aimed at addressing its activity against Streptococcus pyogenes for the treatment of tonsillitis and also it’s potential as a possible source of new antimicrobial product for tonsillitis. Distilled water (maceration method) was used in the extraction of aqueous leaf extracts of Phyllanthus amarus. Different phytochemical screening techniques were used to identify the phytochemicals present in the aqueous leaf extract of Phyllanthus amarus. The Agar well diffusion and broth dilution test methods were used to test for the in-vitro anti-bacterial activity of the aqueous leaf extract of Phyllanthus amarus against Streptococcus pyogenes. The percentage yield of Phyllanthus amarus aqueous leaf extracted was 13.88% (83.3mg). From the results of this research Phyllanthus amarus could be a good source for future drug developments, from the aqueous leaf extract of Phyllanthus amarus in order to address the issue of need for new antibiotics due to the alarming burden of antimicrobial resistance. Keywords: Phyllanthus amarus aqueous leaf extract, Tonsillitis, Streptococcus pyogenes.

Identifikasi Karbon Monoksida Dalam Darah Pada Penjual Buah Di Jembatan Kembar Sungguminasa

The chemical compound of CO gas is a gas that has no color and contributes greatly to environmental pollution as a result of incomplete combustion of fuel produced from motor vehicles. Carbon monoxide is very dangerous (toxic, so it is often referred to as the "silent killer". The presence of CO gas will be very dangerous if inhaled by humans because the gas will replace the position of oxygen that binds to hemoglobin in the blood. The purpose of the study was to identify the presence or absence of carbon monoxide (CO) in the blood of fruit sellers at the Sungguminasa Twin Bridge. This research is an analytical observational field research using the alkaline dilution test method. The sampling technique used purposive sampling with the criteria of working more than one year, working 8 hours a day and not smoking. The number of samples used as many as 9 samples of venous blood. From the results of this study, it can be concluded that the presence of carbon monoxide gas was not identified in all blood samples of fruit sellers at the Sungguminasa Twin Bridge. This is because in the alkaline dilution test method, CO gas can only be identified with saturation levels above 20%.

Lactic Acid Bacteria (Lactobacillus bulgaricus and Streptococcus thermophillus) in Yogurt Inhibit the Growth of Escherichia coli, Salmonella typhimurium, and Shigella sp. In Vitro

Diarrhea is defecation with a frequency more often than usual (three times or more) a day (10 mL/kg/day) with a soft or liquid consistency, even in the form of water alone. Pathogenic bacteria, such as Escherichia coli, Salmonella typhimurium, and Shigella sp., play a role in many cases, to which antibiotics are prescribed as the first-line therapy. However, since antibiotic resistance cases are often found, preventive therapies are needed, such as consuming yogurt, which is produced through a fermentation process by lactic acid bacteria (LAB). This research aimed to determine the activity of lactic acid bacteria (Liactobacillus bulgaricus and Streptococcus thermophilus) in yogurt in inhibiting the growth of the pathogenic bacteria E. coli, S. typhimurium, and Shigella sp. The research applied in vitro with the liquid dilution test method and the true experimental design research method with post-test-only and control group design. The design was used to see the inhibitory effect of yogurt LAB on the growth of E. coli, S. typhimurium, and Shigell sp. to compare the effect of several different yogurt concentrations, namely 20%, 40%, 60%, and 80%. The results of the Least Significance Different analysis showed that there was a significant difference between yogurt with a concentration of 0% and that with various concentrations in inhibiting the growth of E. coli, S. typhimurium, and Shigella sp. with a p-value of <0.05. Whereas, there was no significant difference in the various concentrations of yogurt in inhibiting the growth of the three kinds of bacteria with a p-value of > 0.05.Â

EFEKTIFITAS PAPARAN SINAR UV DAN ALKOHOL 70% TERHADAP TOTAL BAKTERI PADA UANG KERTAS YANG BEREDAR DI MASA PANDEMI COVID-19

Corona virus disease (COVID-19) has become a global pandemic in the world. Indonesia has declared this pandemic as a national disaster. Positive cases and deaths have increased every day. This was a long list of the effects of the COVID-19 pandemic on life. Several solutions have been designed to prevent the rapid transmission of this virus, one of them was by making sterilizer and hand sanitizer products. But there was still debate regarding the effectiveness of the use of UV rays and antiseptics as hygiene products offered.So we need a study to determine the effectiveness of UV exposure and the use of antiseptics to kill germs. This study used an experimental design, the sample used was in the form of folding money taken by the bacteria and grown on the media so that were classified into 3 groups, namely without treatment, 70% alcohol treatment and 10 seconds UV light treatment. The samples were analyzed using the dilution agar method and swab test with two repetitions. The results showed the average number of colony forming units (cfu) of bacteria using the dilution test method and swab test methode were 419 cfu on without treatment group; 4 cfu on alcohol 70% ; and 150 cfu on UV light (10 seconds). The alcohol 70% was more effective than 10 seconds UV light exposure to reduce the amount of bacterial cfu on folding money.

Interaction of aurein 1.2 and its analogue with DPPC lipid bilayer.

Antibacterial peptides have potential as novel therapeutic agents for bacterial infections. Aurein 1.2 is one of the smallest antibacterial peptides extracted from an anuran. LLAA is a more active analogue of aurein 1.2. Antibacterial peptides usually accomplish their function by interacting with bacterial membrane selectively. In this study, we tried to find the reasons for the stronger antibacterial activity of LLAA compared with aurein 1.2. For this purpose, the interaction of aurein 1.2 and LLAA with dipalmitoylphosphatidylcholine (DPPC) was investigated by molecular dynamics (MD) simulation. In addition, the structure of peptides and their antibacterial activity were investigated by circular dichroism (CD) and dilution test method, respectively. MD results showed that LLAA is more flexible compared with aurein 1.2. Furthermore, LLAA loses its structure more than aurein 1.2 in the DPPC bilayer. A higher amount of water molecules penetrate into bilayer in the presence of LLAA relative to aurein 1.2. According to the antibacterial result that indicated LLAA is remarkably more active than aurein 1.2, it can be concluded that flexibility of the peptide is a determining factor in antibacterial activity. Probably, flexibility of the peptides facilitates formation of effective pores in the lipid bilayer.

Investigating the effect of gallium curcumin and gallium diacetylcurcumin complexes on the structure, function and oxidative stability of the peroxidase enzyme and their anticancer and antibacterial activities.

Curcumin has a wide spectrum of biological and pharmacological activities including anti-inflammatory, antioxidant, antiproliferative, antimicrobial and anticancer activities. Complexation of curcumin with metals has gained attention in recent years for improvement of its stability. In this study, the effect of gallium curcumin and gallium diacetylcurcumin on the structure, function and oxidative stability of horseradish peroxidase (HRP) enzyme were evaluated by spectroscopic techniques. In addition to the enzymatic investigation, the cytotoxic effect of the complexes was assessed on bladder, MCF-7 breast cancer and LNCaP prostate carcinoma cell lines by MTT assay. Furthermore, antibacterial activity of the complexes against S. aureus and E. coli was explored by dilution test method. The results showed that the complexes improve activity of HRP and also increase its tolerance against the oxidative condition. After addition of the complexes, affinity of HRP for hydrogen peroxide substrate decreases, while the affinity increases for phenol substrate. Circular dichroism, intrinsic and synchronous fluorescence spectra showed that the enzyme structure around the catalytic heme group becomes less compact and also the distance between the heme group and tryptophan residues increases due to binding of the complexes to HRP. On the whole, it can be concluded that the change in the enzyme structure upon binding to the gallium curcumin and gallium diacetylcurcumin complexes results in an increase in the antioxidant efficiency and activity of the peroxidise enzyme. The result of anticancer and antibacterial activities suggested that the complexes exhibit the potential for cancer treatment, but they have no significant antibacterial activity.

Antibacterial effect of cationic porphyrazines and anionic phthalocyanine and their interaction with plasmid DNA

Resistance to antibiotics is a public health issue and identification of new antibacterial agents is one of the most important goals of pharmacological research. Among the novel developed antibacterial agents, porphyrin complexes and their derivatives are ideal candidates for use in medical applications. Phthalocyanines differ from porphyrins by having nitrogen atoms link the individual pyrrol units. The aza analogues of the phthalocyanines (azaPcs) such as tetramethylmetalloporphyrazines are heterocyclic Pc analogues. In this investigation, interaction of an anionic phthalocyanine (Cu(PcTs)) and two cationic tetrapyridinoporphyrazines including [Cu(2,3-tmtppa)]4+ and [Cu(3,4-tmtppa)]4+ complexes with plasmid DNA was studied using spectroscopic and gel electrophoresis methods. In addition, antibacterial effect of the complexes against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria was investigated using dilution test method. The results indicated that both porphyrazines have significant antibacterial properties, but Cu(PcTs) has weak antibacterial effect. Compairing the binding of the phthalocyanine and the porphyrazines to DNA demonstrated that the interaction of cationic porphyrazines is stronger than the anionic phthalocyanine remarkably. The extent of hypochromicity and red shift of absorption spectra indicated preferential intercalation of the two porphyrazine into the base pairs of DNA helix. Gel electrophoresis result implied Cu(2,3-tmtppa) and Cu(3,4-tmtppa) are able to perform cleavage of the plasmid DNA. Consequently, DNA binding and cleavage might be one of the antibacterial mechanisms of the complexes.

Evaluation of reference dilution test methods for antimicrobial susceptibility testing of Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis.

The development of multidrug-resistant Pseudomonas aeruginosa in patients with cystic fibrosis (CF) is most likely a consequence of increasing life expectancy and more prolonged exposure to antibiotics. The optimal method for antibiotic susceptibility testing of CF strains, particularly mucoid P. aeruginosa strains, is unknown. Antimicrobial susceptibilities of 48 CF strains (25 mucoid) and 50 non-CF strains to 12 anti-Pseudomonas agents were tested by both agar dilution and commercially custom-prepared broth microdilution plates (PML Microbiologicals, Portland, Oreg.) in three laboratories simultaneously to determine if broth microdilution could substitute for agar dilution as the reference method in subsequent studies. Comparison of MICs generated by agar dilution and broth microdilution demonstrated correlation coefficients (r) exceeding 0.85 for all agents tested; correlation was excellent for aminoglycosides (r >/= 0.92) and very good for beta-lactam agents including agents paired with a beta-lactamase inhibitor (r >/= 0.87) and for ciprofloxacin (r = 0.86). Correlation was not improved by 48-h readings, but correlation between 24- and 48-h readings ranged between 0.91 and 0.98 for both methods. Interlaboratory variations were minimal, as the percentage of acceptable variations was 94% for both methods, and serious discords were infrequent (<2% of comparisons). However, CF strains were more likely to have serious discords than were non-CF strains (P < 0. 0001), although mucoid strains were not more likely to have serious discords than were nonmucoid strains. In this study, MICs determined by custom-prepared broth microdilution compared favorably with MICs determined by agar dilution. Thus, this broth microdilution assay can serve as a reference method and facilitate future studies to determine the optimal method for antibiotic susceptibility testing of CF strains.

Antimicrobial activity and spectrum of SCH27899 (ziracin ®) tested against gram-positive species including recommendations for routine susceptibility testing methods and quality control

SCH27899 is an oligosaccharide, everninomicin antibiotic with activity primarily against Gram-positive pathogens. The activity of SCH27899 was evaluated against 360 routine clinical isolates by the broth microdilution (BMD), agar dilution (AD), disk diffusion (DD), and Etest (AB BIODISK, Solna, Sweden) methods. In addition, results from a nine center SCH27899 quality control (QC) trial were used to establish QC ranges. SCH27899 MICs for 330 Gram-Positive strains, including multiply-resistant staphylococci and enterococci, ranged from 0.015 to 1 μg/ml with MIC 90s of 0.12 to 0.5 μg/ml. SCH27899 had no measurable activity against the 30 selected Gram-negative strains tested (MICs, > 256 μg/ml), with the exception of Moraxella catarrhalis MICs, 0.12 μg/ml). Etest MICs for SCH27899 correlated well with AD and BMD results with > 90% of MICs within ± one log 2 dilutions of the reference test results. Three disk concentrations (2.5-, 5-, 10-μg) of SCH27899 were evaluated, but minimal difference of zone diameters between disk drug contents was observed (± 2 mm). SCH27899 disk zone diameters correlated poorly with reference MICs due to small zone diameters (range, 11 to 22 mm) attributed to poor diffusion through agar mediums, a product of this compound’s high molecular weight and solubility. The use of the DD method for SCH27899 was not recommended. The proposed MIC quality assurance limits for SCH27899 using Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 was 0.06 to 0.25 μg/ml for both QC strains and methods. SCH27899 appears to be a eveminomicin-derivative widely active against important Gram-positive cocci, and in vitro dilution testing methods would be preferred for clinical use, validated by the recommended MIC control ranges cited in this report.

Standardized BACTEC method to measure clarithromycin susceptibility of Mycobacterium genavense.

A standardized clarithromycin susceptibility test for Mycobacterium genavense is reported. The BACTEC radiometric broth dilution test method recommended for Mycobacterium avium complex was modified to develop a reliable and reproducible procedure. Test development involved optimization of medium pH and inoculum densities for antibiotic vials as well as growth control vials. MIC control organisms included Mycobacterium simiae, Mycobacterium avium, and Mycobacterium xenopi. Growth control vials required two to three inoculum dilutions, which varied for each species. Clarithromycin MICs and MBCs for 12 isolates and 1 colonial variant of M. genavense ranged from < or = 0.06 to 0.25 microg/ml.

WIN 57273 is bactericidal for Legionella pneumophila grown in alveolar macrophages.

The in vitro antimicrobial activity of WIN 57273, a new quinolone antimicrobial agent, was determined for 21 Legionella strains, using broth macrodilution and agar dilution testing methods; ciprofloxacin and erythromycin were tested as well. Three different buffered yeast extract media were used for the agar dilution studies, two of which were made with starch rather than charcoal. Broth macrodilution susceptibility testing was performed with buffered yeast extract broth and two Legionella pneumophila strains. Antimicrobial inhibition of L. pneumophila growth in guinea pig alveolar macrophages was also studied, using a method able to detect bacterial killing. The MICs for 90% of the 21 strains of Legionella spp. grown on buffered charcoal yeast extract medium were 0.125 microgram/ml for WIN 57273, 0.25 microgram/ml for ciprofloxacin, and 1.0 micrograms/ml for erythromycin. These MICs were falsely high, because of inhibition of drug activity by the medium used. Use of less drug-antagonistic, starch-containing media did not support good growth of the test strains. The broth macrodilution MICs for two strains of L. pneumophila serogroup 1 were less than or equal to 0.03 microgram/ml for WIN 57273 and ciprofloxacin and 0.125 microgram/ml for erythromycin. WIN 57273, ciprofloxacin, and erythromycin all inhibited growth of L. pneumophila in guinea pig alveolar macrophages at concentrations of 1 microgram/ml, but only WIN 57273 prevented regrowth or killed L. pneumophila after removal of extracellular antimicrobial agent.

In-vitro studies of meropenem.

Meropenem, a new carbapenem, was compared with imipenem and seven other broad-spectrum antimicrobial agents against approximately 1000 clinical isolates. Meropenem was two- to four-fold more active than imipenem against Gram-negative organisms and its spectrum of antimicrobial activity was wider than those of all other drugs tested. However, imipenem was more potent than meropenem against the staphylococci, Streptococcus spp. and enterococci. Many rarely isolated organisms were more susceptible to the carbapenems than to other comparison compounds. All anaerobic bacteria were inhibited by meropenem at less than or equal to 8 mg/l and 50% of strains were inhibited by 0.25 mg/l. Meropenem MICs were not significantly influenced by high inocula and the drug was generally bactericidal. Strains producing various beta-lactamases remained susceptible to meropenem but some isolates producing high levels of chromosomally-mediated enzymes showed an inoculum effect only at 10(7) cfu/ml. Meropenem demonstrated antagonism with several other beta-lactams against strains producing Type I cephalosporinases. Susceptibility tests performed on agar and in broth produced very similar meropenem results. Imipenem and meropenem shared a high degree of cross-susceptibility as measured by dilution test methods. Disc diffusion (10-micrograms disc) regression-line correlations with meropenem MICs are reported with two possible sets of interpretive criteria, using meropenem breakpoints of less than or equal to 2 and less than or equal to 4 mg/l.

Resistance of Pseudomonas to Various Chemical Germicides

Abstract Studies were conducted to determine the range of susceptibility of Pseudomonas to seven samples of commercial contact germicides. Tests were made by the official phenol coefficient method, 5.001-5.009. Ranges of resistance for Pseudomonas strains varied with the germicides tested and the concentration of germicide used. Chlorine in water supply systems showed a resistance range of 45-150 ppm to Pseudomonas organisms. Comparative studies were also conducted, using the dilution test method, on various strains of Pseudomonas to determine the effectiveness of disinfectants; strain PRD-10 proved to be the test strain of choice for determining the validity of Pseudomonicidal claims.