Antibiotics Chloramphenicol Research Articles

ChlOR, a GMC family oxidoreductase that evolved independently from the actinomycete, confers resistance to amphenicol antibiotics.

Overuse of the amphenicol antibiotics chloramphenicol (CHL) and thiamphenicol (TAP) poses a great threat to ecosystem safety and human health. The strain, Nocardioides sp. LMS-CY, Nocardioides sp. QY071 and Nocardioides sp. L-11A, classified as a gram-positive actinomycete, harbours a complete CHL metabolic pathway. However, the metabolic genes (clusters) involved in the entire pathway in gram-positive actinomycetes are still limited. Here, chlORLMS , chlORQY071 and chlORL-11A completely from the actinomycete Nocardioides spp. were found to act on the C1 -OH of the CHL/TAP side chain, directly converting CHL/TAP to 4-nitrobenzaldehyde (PNBD)/4-methylsulfonyl benzaldehyde (PMBD) and transforming PNBD/PMBD into 4-nitrobenzyl alcohol (PNBM)/4-methylsulfonyl phenyl methanol (PMBM). Furthermore, oxidoreductases can transform PNBM into 4-nitrobenzoate (PNBA). The oxidoreductases ChlORLMS , ChlORQY071 and ChlORL-11A were all classified as cellobiose dehydrogenases from the glucose methanol choline (GMC) family. Based on the Swiss-Prot database, ChlORQY071 exhibited a lower identity (27.12%-35.10% similarity) with the reported oxidoreductases. Enzymatic and molecular docking analyses showed that ChlORQY071 and ChlORL-11A from the two similar genomes were remarkably more effective in metabolizing CHL than ChlORLMS . Overall, the detailed resistance mechanism of CHL/TAP by actinomycete strains isolated from soil and livestock manure will provide insights into the occurrence of CHL/TAP resistance genes in the environment, resistance risk and bioremediation of CHL/TAP-contaminated environments.

Synergistic Effect of Combined Antibiotic and Methanolic Extracts of Withania somnifera and Catharanthus roseus against MDR Salmonella enterica Serovar Typhi

Typhoid has become the most neglected and majorly affecting disease of tropical and subtropical countries, including India, and is among the most important global health problems, as the emergence of multidrug resistance has shut down the effect of antimicrobial agents and makes it difficult to control the bacteria inside the host. Hence, there is a great need to develop some natural-based drugs, which will be new promising natural therapeutic interventions with high efficacy and lesser side effects in comparison to synthetic drugs already available for typhoid treatment. The present study completely focused on the synergistic effect of bioactive constituents of medicinal plants in combination to synthetic drugs for enhancing the bacterial eradication mechanism. The methanolic extracts of 25 medicinal plants were screened for their antisalmonella effect and out of which only 2 plants were studied further on the basis of their high effectiveness against 17 MDR isolates using well diffusion assay and MIC/MBC determination. The synergistic activity was assessed with two nonantibiotics (ibuprofen and paracetamol) and 3 antibiotics (ceftazidime chloramphenicol, and trimethoprim) using methods of growth inhibitory indices (GIIs) and fractional inhibitory concentration index (FICI). The highly effective methanolic extracts were of W. somnifera and C. roseus, and the synergism was obtained in terms of GIIs and FICI values of 0.9 and 0.3 and 0.9 and 0.5, respectively, fulfilling the criteria for both extracts, respectively. The results for combinations of plant extracts and antibiotics ceftazidime, trimethoprim, and chloramphenicol and nonantibiotics (analgesic drugs) ibuprofen and paracetamol showed good synergistic activity (100%, 88%, 50%, 45%, and 35%, respectively) against the MDR isolates of S. Typhi. The present study also suggests that in the future, combined treatment with the antibiotics and the bioactive compounds can enhance the immune system to perform better action against the external pathogens as well as in the treatment of internal pathogens, and the combinations will be the successful immune modulators.

Effect of Sodium Lactate on the Safety of Cold-smoked Salmon during Cold Storage

Effect of sodium lactate (SL) on inhibition growth of Listeria monocytogenes, L. innocua, Escherichia coli, and Pseudomonas aeruginosa as compared to ampicillin and chloramphenicol antibiotics in cold-smoked salmon stored at 1.0 ± 4.0 0C were evaluated in this study. The sliced smoked salmon were coated with different concentrations of sodium lactate (0.5, 0.75 and 1.0 % SL). Sterilized deionized water was used as a negative control. Total bacterial counts (TBC), lactic acid bacteria (LAB), E. coli (EC), Pseudomonas count (PC) and Listeria count (LC) were examined. In vitro, the antibacterial agent (SL) exhibited antibacterial activities against all the tested bacteria. The antimicrobial action of 1.0 % of SL was more effective than the control. Therefore, thus coating with 1.0 %, SL prevented Listeria spp. and other pathogenic bacteria growth and prolonged the shelf life of cold-smoked salmon.

Novel Starter Strain Enterococcus faecium DMEA09 from Traditional Korean Fermented Meju.

The Enterococcus faecium strain DMEA09 was previously isolated from traditional Korean fermented meju. The objective of the current study was to investigate the traits of E. faecium strain DMEA09 as a starter candidate, focusing on its safety and technological properties. Regarding its safety, the DMEA09 strain was found to be sensitive to nine antibiotics (ampicillin, chloramphenicol, erythromycin, gentamicin, kanamycin, streptomycin, tetracycline, tylosin, and vancomycin) by showing lower minimum inhibitory concentrations (MICs) than the cut-off values suggested by the European Union Food Safety Authority for these nine antibiotics. However, its MIC value for clindamycin was twice as high as the cut-off value. A genomic analysis revealed that strain DMEA09 did not encode the acquired antibiotic resistance genes, including those for clindamycin. The DMEA09 strain did not show hemolysis as a result of analyzing α- and β-hemolysis. It did not form biofilm either. A genomic analysis revealed that strain DMEA09 did not encode for any virulence factors including hemolysin. Most importantly, multilocus sequence typing revealed that the clonal group of strain DMEA09 was distinguished from clinical isolates. Regarding its technological properties, strain DMEA09 could grow in the presence of 6% salt. It showed protease activity when the salt concentration was 3%. It did not exhibit lipase activity. Its genome possessed 37 putative protease genes and salt-tolerance genes for survivability under salt conditions. Consequently, strain DMEA09 shows safe and technological properties as a new starter candidate. This was confirmed by genome analysis.

Novel 2-Acetamido-2-ylidene-4-imidazole Derivatives (El-Saghier Reaction): Green Synthesis, Biological Assessment, and Molecular Docking.

El-Saghier reaction is the novel, general, and green reaction of various amines with ethyl cyanoacetate and ethyl glycinate hydrochloride. A new series of imidazolidin-4-ones and bis-N-(alkyl/aryl) imidazolidin-4-ones was synthesized in a sequential, one-pot procedure under neat conditions for 2 h at 70 °C. Excellent high yields (90-98%) were achieved in a short period of time while avoiding issues related to the hazardous solvents utilized (cost, safety, and pollution). The spectrum analyses and elemental data of the newly synthesized compounds helped us to clarify their structures. The obtained compounds were tested for antibacterial activity in vitro and compared to the standard antibiotic chloramphenicol as the standard, measuring the inhibition zone (nm) and activity index (%). With an antibacterial percentage value of 80.0 against Escherichia coli, N,N'-(propane-1,3-diyl) bis(2-(4-oxo-4,5-dihydro-1H-imidazole-2-yl) acetamide) proved to be the most effective. Antimicrobial activity was confirmed by a molecular docking investigation to investigate how chemicals bind to the bacterial FabH-CoA complex in E. coli (PDB ID: 1HNJ).

Isolation and characterization of bioprotective lactic acid bacteria from Moroccan fish and seafood.

The microbiota of aquatic animals is heavily influenced by their environment, offering a potential source for biotechnologically relevant microorganisms. In this investigation, bacterial strains from fish and fish products were investigated to determine their antimicrobial effects against fish and food pathogens. Twelve strains, including five Lactococcus, two Enterococcus hirae, two Enterococcus mundtii, and three Latilactobacillus sakei were selected as producing bacteriocin-like substances with antimicrobial properties that were active against a broad spectrum of bacteria, such as Listeria monocytogenes, Staphylococcus aureus, and Pseudomonas aeruginosa. Selected strains were identified via 16S rRNA sequencing. Most strains exhibited sensitivity to eight types of antibiotics (erythromycin, tetracycline, chloramphenicol, vancomycin, fosfomycin, gentamicin, ampicillin, and netilmicin), lacked hemolysin and gelatinase virulence factors, and did not produce histamine. These findings suggest that marine fish may be a promising source of lactic acid bacteria strains with antimicrobial potential for use as biopreservatives in the food industry.

Chemical composition and antioxidant/antibacterial depictions of Zahidi date palm (Phoenix dactylifera) kernel Oil

Date palm “Phoenix dactylifera” variety Zahidi is a unique well-known cultivar. Mature fruits are semi-dry, medium size, cylindrically shaped and golden brown. However, there are three stages to harvesting the dates soft, hard or semi-soft. In this research, the oil processed from the seed/kernel of the date palm Zahidi is chemically analysed for its composition, antioxidant capacity and its antibacterial properties were investigated. Date seeds were ground and extracted for the oil. Wet chemical analyses were implemented on the extracted oil via various analytical techniques such as high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC–MS). Oil fractions of ethanol, methanol and acetone were tested for antibacterial activity, which was evaluated employing the Kirby–Bauer disc-diffusion method. Antibacterial action was examined for four bacterial strains; two of them representing Gram-positive such as Bacillus subtilis, and Staphylococcus aureus, and the other two for Gram-negative such as Pseudomonas aeruginosa and Escherichia coli. The antibiotics tetracycline, chloramphenicol, streptomycin, gentamycin and vancomycin were used as positive standards. The Minimum Bactericidal Concentration (MBC) and Minimum Inhibitory Concentration (MIC) of the bacterial strains were tested and evaluated. The antioxidant activity was evaluated as free-radical scavenging capacity (RSC) towards 2,2 - diphenyl -1-picrylhydrazyl (DPPH) radicals for the methanol fraction (MF), remaining lipid fraction (LF) and non-fractioned oil, i.e., the total fraction (TF). The RSCs for the MF, LF and TF were 42.5, 9.1 and 68.3, respectively. Zahidi seed/kernel oil extract inhibited all of the test microorganisms, with MICs that ranged from 10 to 42 mg/mL and MBCs were found to be ranged between 21 and 167 mg/mL. These outcomes suggest that the extracts could be developed as a foundation of expected antimicrobial complexes to fight unwanted bacteria in foods. Overall, the results showed that the oil is suitable for food, cosmetics, personal care products and pharmaceuticals.

Construction of a Cd(II)-Based Metal-Organic Framework for Selective Luminescent Sensing of Chloramphenicol in Milk and Honey Samples

A new and water-stable metal-organic framework, [Cd2(L)2(tmd)]·3H2O (MOF 1), was successfully synthesized by mixed ligands of H2L and tmd under solvothermal condition (H2L= 5-acetamidoisophthalic acid, tmd= 4,4-trimethylenedipyridine). Single-crystal X-ray diffraction shows that the structural unit of MOF 1 is a tetranuclear [Cd4(L)6] primary building unit. Fluorescence sensing experiments revealed that MOF 1 exhibited selectivity and sensitivity detection of Chloramphenicol (CHL) antibiotic in aqueous solutions. The fluorescence quenching effect showed that MOF 1 had a very low detection limit for CHL (LOD= 0.11 μM). More importantly, MOF 1 can be used as a new fluorescence sensor for the detection of CHL in milk and honey samples with very good recoveries of 98.2-103.0 % and 97.0-98.9 %, respectively. Furthermore, the internal filtration effect (IFE) and photoelectron electron transfer (PET) may be responsible for the fluorescence quenching efficiency.

Implementation of visible light-driven photocatalytic degradation of antibiotic chloramphenicol using Bi2S3/ZrO2 and Bi2WO6/ZrO2 heteronanostructures

Zirconium dioxide-incorporated bismuth sulfide (Bi2S3/ZrO2) and bismuth tungstate (Bi2WO6/ZrO2) heteronanostructures (HNSs) were fabricated to serve as photocatalysts for the visible light-driven degradation of antibiotic chloramphenicol (CAP). A two-step hydrothermal process was applied to synthesize HNSs, and their structural and optical properties were validated by several analytical techniques. Interestingly, a multi-structural feature was ascertained in which nanoflower-structured ZrO2 was attached to the surface of nanorod- and nanosheet-structured Bi2S3 and Bi2WO6, respectively, resulting in the formation of Bi2S3/ZrO2 and Bi2WO6/ZrO2 HNSs. For the photocatalytic degradation of CAP, both HNSs showed magnificent catalytic activity during a visible light-based photocatalytic degradation. Furthermore, when peroxymonosulfate (PMS) was used as an activator for an oxidative catalytic reaction, the photocatalytic degradation rate was drastically enhanced to nearly 5 times. Bi2S3/ZrO2 and Bi2WO6/ZrO2 showed ∼96 % CAP degradation in 15 min, with rate constants of 0.2511 and 0.2163 min−1, respectively. The synergistic effects of the substantial generation and separation of photoinduced charge carriers are responsible for the highly improved catalytic activity. Scavenger analysis demonstrated that hydroxyl radical species predominated in the effective degradation process. These kinds of inorganic-based HNSs are expected to rule the field of contaminated water remediation, which will also expand a platform for the fabrication of photocatalyst materials.

Development of microbiological diffusion inhibition test for the determination of antibiotic residues in the milk

Antimicrobial agents are used in animal husbandry for the prevention and treatment of diseases in farm animals and have become an indispensable aspect of commercial livestock production. Antimicrobial therapy is well-established as a component of comprehensive preventive measures aimed at minimizing diseases in farm animals and has been incorporated into procedures directed at promoting livestock growth and productivity. Bacillus licheniformis strain T7 is susceptible to the antibiotics clidamycin, rifampicin, erythromycin, ciprofloxacin, tobramycin, tetracycline, penicillin, streptomycin, and chloramphenicol, has good sporogenic properties, grows rapidly on nutrient agar at 30-55 °C, pH 5.5–8.0, and can serve as a test culture in a microbial inhibitor test. Bacillus licheniformis T7 spores were obtained by growing the culture in Difco sporulation medium and then inactivating the vegetative cells at 90 °C for 20 minutes. Endospores of Bacillus licheniformis T7 co-polymerized with nutrient agar and germinated at 55 °C for 3–3.5 h, resulting in a pH shift from 5.5 to >6.5, which can be measured with an acid-base indicator. Bromocresol purple was suggested as a pH indicator for use in a microbiological inhibition test, wherein the presence of antibiotics or other compounds impeding the development of a microbiological culture could be determined by a change in the agar's color. A microtube- and plate-based microbiological inhibitor test prototype has been developed.

Antimicrobial susceptibility pattern of Escherichia coli isolated from dairy calves with diarrhoea in Akaki Kality, Addis Ababa, Ethiopia

ABSTRACT Calf diarrhoea, the eighth most common cause of death in this age group, affects over 75% of newborn calves under three weeks old. Fifty calves with diarrhoea from the nine intensive dairy farms were assessed during the study period. Of these, 72% (n =36) were positive for E. coli There was a strong link between the prevalence of E. coli in calf diarrhoea and the age groups. Therefore, those under the age of one month were 1.3 more likely to be infected with E. coli than those between one and three months of age. The Antibiogram test revealed that E. coli isolated was highly responsive to the antibiotics tetracycline, chloramphenicol, sulfamethoxazole, streptomycin and doxycycline, but less susceptible to the drugs amoxicillin, ceftazidime, nitrofurantoin, and kanamycin and resistant to the antibiotics cefotaxime and vancomycin. Results from interviews and regular observations in the study area indicate that young calves were more impacted by diarrhoea, which accounted for about half of all health issues in calves. The E. coli recovery rate was significantly higher in calves that were one week old. These findings supported the hypothesis that the level of calf diarrhoea was excessive and would be detrimental to dairy output.

Risk Threshold and Assessment of Chloramphenicol Antibiotics in Sediment in the Fenhe River Basin, China.

Chloramphenicol antibiotics (CAs) are broad-spectrum antibiotics which are widely used in the prevention and treatment of infectious diseases in livestock and poultry breeding. However, overused CAs can enter the watershed and eventually enter the sediment. Antibiotics in sediment can cause secondary pollution through disturbance and suspension. In this study, taking the Fenhe River Basin as the research area, the risk of CAs in sediment were assessed by collecting sediment samples. The results showed that CAs were detected in all sediment samples of the Fenhe River Basin. The mean concentration of CAs was 79.1 μg/kg, and the concentration of thiamphenicol (THI) was dominant, which was up to 58.3 μg/kg. Temporally, there are great differences in different seasons; the concentration of CAs was higher in winter than that in summer, up to 4.79-174 times. Spatially, the mean concentration of CAs in midstream was 83.5 μg/kg, which was higher than that in the upstream and downstream. The concentration of CAs in tributaries were generally higher than that in the main stream, and the mean concentration of tributaries was 1.1 times that of the main stream. CAs in S2 (Lanhe River) was the most prominent among all sample sites; the concentration of CAs was 190.8 μg/kg. The risk threshold of CAs in the sediment was calculated using the Equilibrium Partitioning approach (EqP), based on the distribution coefficient (Kp) and the predicted no-effect concentration (PNEC) in the water, and the values were 0.091-1.44 mg/kg. Based on the risk threshold, the ecological risk of the CAs in sediment was assessed using risk quotients (RQ). The results showed that the Chloramphenicol (CHL) was the most prominent in the Fenhe River Basin, and the proportion of medium-risk areas reached 21.7%, while all the other areas showed low risk. Secondly, the proportion of medium-risk areas was 17.4% for THI, and all the other areas showed low risk. The risk for Florfenicol (FF) was least among all CAs, and the proportion of low-risk areas was only 8.7%, while all the other areas were of insignificant risk.

Antibacterial Test of Teki Grass Extract (Cyperus Rotundus) in Inhibiting Escherichia Coli and Salmonella Typhi

This study aims to determine the antibacterial ability of Cyperus rotundus extract in inhibiting the growth of Escherichia coli and Salmonella typhi by measuring the diameter of the inhibition zone. This research method used a completely randomized design (CRD) and LSD test as a follow-up test with one factor, namely variations in the concentration of C. rotundus extract 20%, 40%, 60%, 80% and 100%, distilled water as a negative control and the antibiotic chloramphenicol as a positive control. The results showed that the extract of C. rotundus could inhibit the growth of Escherichia coli with the largest inhibition zone diameter indicated by a concentration of 100% which was 2.33mm and the smallest inhibition zone diameter was found at a concentration of 20%, namely 1.00 mm. While in Salmonella typhi the largest inhibition zone was shown at a concentration of 100%, namely 3, 03mm and the smallest inhibition zone was indicated by a concentration of 20%, namely 1.07 mm. The results of the ANOVA and LSD tests with 95% confidence test showed that there was a difference in the average diameter of the inhibition zone in each treatment with variations in the concentration of C. rotundus extract with a concentration of 80% as the most effective.

Estimate of the most common bacteria cause of UTI and effective drug in Alrefaai City

Background: Urinary Tract Infection is a worldwide prevalence disease that infects both males and females in different ratios. Escherichia coli is the most infectious pathogen, followed by Klebsiella and Pseudomonas. Through time bacteria increase their resistance to most antibiotics, increasing bacterial prevalence and pathogenesis. Fifty patients with UTI symptoms were randomly selected in Alrefaai Hospital from October 2021 to April 2022. A 10-15 ml urine sample was collected from each patient and cultured to calculate colony forming unit and detect the type of bacteria with biochemical tests. Most patients were female 66% compared to male 34% with age groups 1-30 years 68% and those more than other groups. Escherichia coli is the most prevalent, 54%, while the second one is Staphylococcus aureus 20%, then Coagulase -ve Staphylococcus 14% and less infection was with Klebsiella and Proteus, 6%. Antibiotic Imipenem, Chloramphenicol, Gentamycin, Norfloxacin, Ciprofloxacin and Tobramycin play highly effective roles on most bacteria. We found that most patients with UTI were from the city center and in the age group 1-30 years. The most prevalent pathogens of UTI were Escherichia coli and then Staphylococcus aureus. Almost Imipenem, Chloramphenicol, Gentamycin, Norfloxacin, Ciprofloxacin and Tobramycin are the best effective antibiotics against our study's bacteria. Keywords: Urinary Tract Infection, Recurrent UTI, Alrefaai city, Antibiotic susceptibility.

Frequency of dermatophytes and yeasts on tegument of healthy dogs and cats

Skin is an organ that covers the body and acts as a protective layer against external aggressions. Changes in this organ, such as hair loss, evident blemishes, changes in skin pigmentation, and the presence of scaling or crusts, are the main signs of dermatological disease. The study aimed to verify the frequency of dermatophytes and yeasts in healthy cats and dogs. Samples of hair and shedding from 30 cats and 30 dogs were cultured on dermatophyte test medium and Sabouraud Dextrose agar enriched with yeast extract, thiamine, antibiotics (streptomycin and chloramphenicol) supplemented with cycloheximide and incubated at 25°C and 35°C for 10 days. The positive cultures were assessed macro and microscopically, and the fungi were identified by biochemical methods. It was found that 100% of the cats had a positive mycological culture for Microsporum canis, 33.33% for Microsporum gypseum, and 50% for Trichophyton mentagrophytes, with a prevalence of Microsporum canis (P>0.001). In dogs, 86.66% were positive for Microsporum canis, showing a predominance over the other fungal species (P<0.001). Malassezia pachydermatis was isolated in 50% of the dogs evaluated, although it was not found in cats, while positive cultures for Malassezia spp were found in 6.6% of cats and 26.66% of dogs. Candida albicans was isolated in samples of dogs and cats (26.66% and 33.33%, respectively). It was concluded that asymptomatic dogs and cats are carriers of agents of dermatophytosis and dermatomycoses and may be important sources of environmental spread and intra and interspecific infection.

Anti-urinary tract infection activity of selected herbal extract towards isolated Kosakonia cowanii (OQ 073698)

Urinary Tract Infection (UTI) is one of the most common types of infection caused by the gastrointestinal tract of humans. UTI is the most common in women because a women''s urethra is shorter. In the present investigation, four UTI-causing bacteria were isolated on MacConkeys as well as on UTI agar media which is selective for UTI pathogens only. The isolated bacteria were tested for antibiotic resistance towards the selective antibiotics Ampicillin (10µg), Penicillin (10µg), and Chloramphenicol (30µg). Based on antibiotic resistance and morbific nature, the organism was screened. On the basis of morphological, biochemical characteristics and the 16S r-RNA sequencing method the organism was identified as Kosakonia cowanii. The nucleotide sequence was deposited to NCBI and received a unique accession number (OQ 073698). The anti-UTI activity was performed towards selective medicinal herbs by using ethanol, methanol and water as solvent extraction methods. The Embilica officinalis ethanolic extract (1 mg/ml) and standard antibiotic chloramphenicol showed 1.8 mm zone of inhibition against K. cowanii (OQ 073698). From the present study, it is concluded that E. officinalis ethanolic extract was effective to treat UTI infection. Another core finding from the present study includes - an isolated pathogen that was earlier resistant to ampicillin but when combines with E. officinalis and Boerhavia diffusa ethanolic extracts separately showed 2.0 mm zone of inhibition.

Antimicrobial agents in small animal dermatology for treating staphylococcal infections.

Antibiotic recommendations for treating skin infections have been published many times in the past 30 years. Prior to 2000, the recommendations focused on the use of β-lactam antibiotics, such as cephalosporins, amoxicillin-clavulanate, or β-lactamase stable penicillins. These agents are still recommended, and used, for wild-type methicillin-susceptible strains of Staphylococcus spp. However, since the mid-2000s there has been an increase in methicillin-resistant Staphylococcus spp (MRSP). The increase among S pseudintermedius in animals coincided with the increase in methicillin-resistant S aureus that was observed in people near the same time. This increase led veterinarians to reevaluate their approach to treating skin infections, particularly in dogs. Prior antibiotic exposure and hospitalization are identified as risk factors for MRSP. Topical treatments are more often used to treat these infections. Culture and susceptibility testing is performed more often, especially in refractory cases, to identify MRSP. If resistant strains are identified, veterinarians may have to rely on antibiotics that were previously used uncommonly for skin infections, such as chloramphenicol, aminoglycosides, tetracyclines, and human-label antibiotics such as rifampin and linezolid. These drugs carry risks and uncertainties that must be considered before they are routinely prescribed. This article will discuss these concerns and provide veterinarians guidance on the treatment of these skin infections.

The Activity of Some Antibiotics Depend on Stereochemistry of Them (Its Structure)

The chiral carbon in biological compounds lead to its activity, for example, the beta lactam ring contains two carbon centers carbon number three and carbon number four both are chiral carbon. This chirality plays important role in the activity and bind with structures activity relationship. Also the ofloxacin act on topoisomerase which required for protein Synthesis of microorganism, the ofloxacin when become Levo isomer not only racemic mixture the activity is more than the racemic or Dextro isomer. Also, the old Antibiotics Chloramphenicol the RR’ isomers only active not the other isomers of Chloramphenicol.

Dressings produced from PVA nanofibers containing chloramphenicol

In this study, electrospun PVA membranes crosslinked with citric acid or glutaraldehyde and containing the antibiotic chloramphenicol (CLF) were obtained for the production of dressings. This material was characterized by SEM, FTIR, DSC, TGA NMR, degree of swelling, and solubility. The SEM images showed the possibility of obtaining nanofibers with a diameter between 600 and 700 nm. Crosslinking with citric acid (3% m/m) was the only one able to give stability to PVA fibers in water and preserve their morphology. The stability of PVA fibers in water was associated with a decrease in OH groups in PVA and an increase in crystallinity, both effects promoted by crosslinking. The increase in crystallinity due to crosslinking was observed by DSC, DRX, and FTIR analyses. A linear correlation was found between the increase in enthalpy of fusion and the increase in crystallinity. The FTIR analysis confirmed the incorporation of the drug into the fibers. The results of TGA analysis suggested that the presence of basic groups in the CLF molecule may act as proton receptors delaying the first stage of thermal degradation of the polymer. The absence of CLF-related peaks in the X-ray diffractograms and DSC curves suggests that the drug may be in an amorphous state, which improves the solubility of CLF and facilitates its immediate release, making the drug more bioavailable. The mechanism of CLF release indicated that the kinetics follows the typical Weibull model for matrix systems, showing an immediate release in the first 30 min. The membranes exhibited hemotoxicity below the limit established by ASTM F756–08. In addition, the disk diffusion tests showed antimicrobial activity against S. aureus, S. epidermidis, and P. aeruginosa strains, indicating that these membranes are promising for use in wound dressings with anti-infective biological activity.

The Antibacterial Activity of Gambir Extract (Uncaria gambir (hunter ) Roxb ) Against Salmonella typhi

هههTyphoid fever is still a severe issue in the world. The pharmacological therapy used for typhoid fever was chloramphenicol antibiotics. However, chloramphenicol resistance to Salmonella typhi is common, so finding alternative antibacterial drugs for typhoid fever is necessary. Gambir Extract was a natural ingredient often used in non-pharmacological alternative therapies. It contained secondary metabolites such as alkaloids, flavonoids, tannins, and saponins which are suspected to be antibacterial. This study aimed to identify the Minimum Inhibitory Concentration and the Minimum Bactericidal Concentration values of Gambir Extract against Salmonella typhi. The antibacterial activity of the Gambir Extract against Salmonella typhi was screened using the well diffusion method. The MIC and MBC of the Gambir Extract were determined using the dilution method. Data were analyzed using the Kruskal-Wallis test and the Mann-Whitney test. The inhibition zone of the antibacterial activity of the Gambir Extract against Salmonella typhi was 19.22 mm and had a MIC value of 50% (0.5 g/ml). The statistical analysis results of the Kruskal-Wallis and the Mann-Whitney test obtained significance values of 0.007 and 0.025. Therefore, Gambir Extract cannot kill Salmonella typhi. Gambir Extract has antibacterial activity against Salmonella typhi with a MIC value of 0.5g/ml.
 Keywords: Antibacterial, Gambir, Minimum Bactericidal Concentration (MBC), Minimum Inhibitory Concentration (MIC)