Methicilin-resistant Staphylococcus Aureus Research Articles

Synthesis, and molecular docking of thiourea derivatives as antibacterial agents targeting enzymes involved in biosynthesis of bacterial cell wall

Background: New antibacterials are needed due to the increasing resistance of bacteria to existing antibiotics. Thiourea derivative compounds (benzoylthiourea and 1,3-dibenzoylthiourea) contain aromatic groups, thio groups (C=S), and amide groups (H2N-C=O), which are commonly found in the class of antibacterial drugs. Molecular docking can be used to predict their antibacterial activity.     Objective: This study aimed to synthesise thiourea derivatives and predict their antibacterial activity by in silico method.     Methods: Synthesis was performed using nucleophilic substitution reactions. The synthesised compounds were identified using UV-Vis, FT-IR, and 1H-NMR. Molecular docking was conducted using the MOE program ver 2022.02.    Results: Benzoylthiourea (BTU) and 1,3-dibenzoylthiourea (DBTU) compounds were obtained with yields of 36.55% and 12.68%, respectively. The melting point 171-173°C for BTU and 202-204°C for DBTU. Molecular docking results showed higher binding affinity of DBTU against PBP2a (docking score < -5.75 kcal/mol) and FaBH (docking score <-4.7935 kcal/mol) compared to the corresponding native ligands, while the two compounds had lower affinity for the muramyl ligase.     Conclusion: BTU and DBTU can be synthesised by nucleophilic substitution reactions. DBTU is predicted to exhibit antibacterial activity against Methicilin Resistant Staphylococcus aureus (MRSA) and Mycobacterium tuberculosis.

Screening of Haliclona sp. symbiont bacteria that have the potential as MDR (Multidrug-Resistant) antibacterial from Tanjung Tiram Beach

Sponge Haliclona sp. is a type of sponge living in marine waters and is found in many areas of coral reef ecosystems. This study aimed to determine the potential for sponge Haliclona sp. obtained from Tanjung Tiram waters, Konawe, as a source of bioactive compounds of MDR (Multidrug-Resistant) antibacterial. The isolation method of Haliclona sp. symbiont was carried out by pouring and purification of Haliclona sp. symbiont using the scratch method. The purification results obtained 12 isolates of symbiont bacteria that were successfully isolated. Then the bacterial isolate was tested for its antibacterial ability against MRSA and ESBL Escherichia coli bacteria qualitatively using the agar diffusion method. Bacteria that have strong inhibitory activity are identified by morphological and biochemical tests. The results of the qualitative screening test produced four bacterial isolates that have inhibitory activity against MRSA (Methicilin Resistant Staphylococcus aureus) pathogenic bacteria with the isolate codes H3 and H8 belonging to the strong category while H4 and H10 belonging to the medium categoy. Additionally, two bacterial isolates that have inhibitory activity against ESBL Escherichia coli pathogenic bacteria with the isolate codes H3 and H8 belonging to the strong category. Based on morphological observations and biochemical tests, the H3 bacterial isolate was identified as the genus Corynebacterium spp. and the H8 bacterial isolate was identified as the genus Micrococcus spp. In conclusion, Haliclona sp. sponge exhibits promising potential as a source of microorganism producing antibacterial compounds, particulary againts MDR (Multidrug-Resistant) strains.

Mechanistic insight into the synergistic antimicrobial potential of Fagonia indica Burm.f. extracts with cefixime

Fagonia indica Burm.f. is known for its anti-infective character and has been studied in the present work as a synergistic remedy against resistant bacterial strains. Initially, phytochemicals were quantified in n-Hexane (n-Hex), ethyl acetate (E.A), methanol (MeOH), and aqueous (Aq.) extracts by Total Phenolic Content (TPC), Total Flavonoid Content (TFC) and Reverse Phase High Performance Liquid Chromatography (RP-HPLC) analysis. Later, after establishing an antibacterial resistance profile for extracts and antibiotics against gram-positive and gram-negative strains, synergism was evaluated in combination with cefixime through time-kill kinetics and bacterial protein estimation studies. Topographic images depicting synergism were obtained by scanning electron microscopy for Methicilin-resistant Staphylococcus aureus (MRSA) and Resistant Escherichia coli (R.E. coli). Results showed the presence of maximum phenolic (28.4 ± 0.67 μg GAE/mg extract) and flavonoid (11 ± 0.42 μg QE/mg extract) contents in MeOH extract. RP-HPLC results also displayed maximum polyphenols in MeOH extract followed by E.A extract. Clinical strains were resistant to cefixime whereas these were moderately inhibited by all extracts (MIC 150–300 µg/ml) except Aq. extract. E.A and n-Hex extracts demonstrated maximum synergism (Fractional inhibitory concentration index (FICI) 0.31) against R.E. coli. The n-Hex extract displayed total synergism against R.P. a with a 4-fold reduction in cefixime dose. Time-kill kinetics showed maximum inhibition of gram-negative bacterial growth from 3 to 12 h when treated at FICI and 2FICI values with > 10-fold reduction of the extracts’ dose. All combinations demonstrate > 70 % protein content inhibition with bacterial cell wall disruption in SEM images. Fortunately, FICI concentrations have low hemolytic potential (<5%). Conclusively, F. indica extracts can mitigate antimicrobial resistance against cefixime and can be investigated in detail by in vivo and mechanistic studies.

Synergistic Effect of Baccharis dracunculifolia DC and Green Propolis with Antimicrobial Drugs against Staphylococcus aureus

Abstract: Relevance: This study demonstrated the synergism of various natural preparations in combination with antibiotics, which is a matter of high potential therapeutic interest due to the de- velopment of bacterial resistance to these antibiotic drugs. This synergism is very relevant because it demonstrates that these extracts and their association with these antibiotics may be viable thera- peutic options against the pathogens that are responsible for a high incidence of nosocomial and community infections. Aims: The study investigated the antibacterial activity against Staphylococcus aureus isolates (methicilin-sensitive Staphylococcus aureus (MSSA) and methicilin-resistant Staphylo- coccus aureus (MRSA)) of green propolis and Baccharis dracunculifolia DC. ethanolic extracts com- bined with classical antibiotics. Methods and Results: In the test of the antibacterial activity of the combination of classical antibiotics with natural extracts (ten antibiotics plus one association of two antimicrobial disc diffusions), 25 isolates were used. The isolates were inoculated in Müeller–Hinton agar culture medium containing the green propolis and Baccharis dracunculifolia DC. extracts. Bac- charis dracunculifolia DC ethanolic extract (BDEE) showed higher antibacterial synergistic behavior with the antibiotics tested than green propolis ethanolic extract (PVEE). Conclusions: BDEE was the preparation that showed the best synergistic antimicrobial effect in sub-doses with the tested anti- biotics. These activities may be related to Artepillin C, the major compound in PVEE, and nerolidol, the major compound in BDEE, in synergism with other minority compounds and related antibiotics.

Prevalence and Antibiotics resistance profile of Staphylococcus aureus isolated from post-operative wounds in secondary health facilities of Ilorin metropolis, Kwara State, Nigeria

Healthcare-associated infections are of different forms, with Surgical Site Infections (SSI) being the second most common type, they continue to be a relatively common postoperative complications and the most frequent reason for re-admission following surgery. Several data from around the world revealed Staphylococcus aureus to be the leading cause of surgical site infection. Therefore, this study aimed to determine the occurrence and drug resistance profile of Staphylococcus aureus and Methicilin Resistant Staphylococcus aureus isolated from post-operative wounds in secondary health facilities within the Ilorin metropolis. With the aid of sterile cotton swabs, a total of hundred and thirty-two (132) wound swab samples were obtained from patients who had been clinically diagnosed with surgical site infection. These samples were processed as per standard microbiological techniques. Staphylococcus aureus was isolated at an occurrence rate of 15.2%. Chi-square analysis showed that there was a significant difference in the number of isolates in relation to both hospitals (GHI and CHO) (p&lt;0.05), the highest occurrence of Staphylococcus aureus (12.6%) was seen in GHI, while an occurrence rate of (24.1%) was recorded at CHO. The antimicrobial susceptibility profile revealed that 8(40%) of the S.aureus isolates were Methicilin Resistant Staphylococcus aureus (MRSA). S.aureus showed 100% susceptibility to Tigecycline and it was 100% resistant to Cefoxitin.  Therefore, these findings affirmed that there is significant resistance in Staphylococcus aureus isolated from post-operative wounds in health facilities of the Ilorin metropolis.&#x0D;  

Antibacterial Potential of Seagrass Cymodocea Rotundata (Alismatales: Cymodoceaceae) Extract on The Pathogenic Bacteria Staphylococcus Aureus

Staphylococcus aureus is classified as a pathogenic bacterium in humans and animals. S. aureus infection in humans can cause skin infections, and produce toxins that result in shock syndrome, foodborne disease, bacteremia, endocarditis, metastatic infections, and sepsis, while in milk-producing animals it can cause mastitis infection. Initially, S. aureus can be overcome with penicillin antibiotics but often develops time S. aureus becomes resistant to penicillin to cause new infections, namely the Methicilin Resistant Staphylococcus aureus (MRSA) which was first reported in 1961. One of the natural ingredients from the sea that has natural antibacterial content is seagrass or Cymodocea rotundata. Which is one type of seagrass in Indonesia that is included in the round type of grass. Cymodocea rotundata has bioactive components such as alkaloids, flavonoids, phenol hydroquinone, steroids, triterpenoids, tannins, and saponins that function as antibacterials. This study aims to determine the potential of seagrass Cymodocea rotundata as an antibacterial against Staphylococcus aureus bacteria. This research is experimental research using wells. Samples of Cymodocea rotundata seagrass came from the coastal waters of Ketapang and were converted into a simplified powder form with ethanol solvent. The results showed that the diameter of the inhibition zone formed ranged from 5.5 mm - 9.7 mm, the largest in the 40% treatment. Based on this research, it can be concluded that the extraction of seagrass Cymodocea rotundata has benefits as an antibacterial and potential in the field of pharmacology.

PROFILING PHYTOCHEMICALS AND ANTIMICROBIAL ACTIVITIES OF HEXANE AND ACETONE CRUDE EXTRACTS OF Sterculia setigera LEAF

Assessment of phytochemicals and antimicrobial activities of different solvent (hexane and acetone) extracts of the leaf of Sterculia setigera were carried out using standard methods. 200 g of the dried leaves was macerated using 400 mL of each solvent in increasing polarity for the extraction, with percentage yield of 7.87 and 8.74% for hexane and acetone respectively. Phytochemical screening of the crude extracts showed the presence of alkaloids, terpenoids, tannins, phenol, steroids and phlobatannins; glycosides were present in hexane extract only while saponins where present in acetone extract only. Using the diffusion method, both extracts showed visible inhibitory effect when compared to the positive control against Methicilin resistant Staphylococcus aureus (MRSA), Vancomycin resistant Enterococci (VRE), Escherichia coli, Campylobacter jejuni, Salmonella typhi, and Candida tropicalis except for Staphylococcus aureus, Helicobacter pylori, Candida albicans and Candida tropicalis that were resistant. Although, both extracts exhibited antimicrobial activities, acetone extract showed slightly more activities than that of the hexane extract. This, therefore, offers scientific basis for the traditional use of plant Sterculia setigera for the treatment of Mycobacterium tuberculosis, malaria, jaundice, measles, syphilis and leprosy.&#x0D;  

Efektivitas antibakteri ekstrak daun sisik naga (Drymoglossum piloselloides) terhadap bakteri MRSA (methicilin resistant Staphylococcus aureus) dan Eschericia coli

The purpose of this research aimed to determine the antibacterial effectiveness of the methanolic extract of dragon scales leaves (Drymoglossum piloselloides) against MRSA (Methicilin-resistant Staphylococcus aureus) and Eschericia coli bacteria in vitro using the diffusion method. This research used a population of Methicillin-resistant Staphylococcus aureus and Eschericia coli bacteria. The sample to be used is dragon scale leaf methanol extract. The method in this research used experimental with 6 treatments, namely dragon scale leaf methanol extract with concentrations of 45%, 55%, 65%, 75%, negative control (methanol) and positive control  (chloramphenicol antibiotics). Data collection in this study was carried out by recording the diameter of the inhibition zone using a caliper (mm). The data obtained from the diameter of the inhibition zone of 75% extract variation resulted in an inhibition zone of 17.02 mm (in MRSA) and 8.47 mm (in E.coli). Chloramphenicol was found to be resistant to MRSA, but sensitive to E.coli. Data analysis used  ANOVA test which statistically showed that there was a significant difference (P&lt;0.05) in the diameter of the inhibition zone of the dragon scale leaf methanol extract against MRSA bacteria and there was a very significant difference (P&lt;0.01) in the diameter Inhibition zone of dragon scale leaf methanol extract against Eschericia coli bacteria.

Safety and efficacy of Lucilia cuprina maggots on treating an induced infected wound in Wistar rats

Infection is one of the main complications that hinder wound healing. Currently, antibiotic-resistant bacteria, such as Methicilin-resistant Staphylococcus aureus (MRSA), are a concern worldwide for both humans and animals. Maggot therapy is re-emerging as an alternative to intractable wounds and may be an option to the traditional antibiotic treatment. Although the species of choice is Lucilia sericata, reports of clinical use have led us to evaluate the efficacy and safety of using Lucilia cuprina larvae on induced infected wounds in Wistar rats. In short, 32 male Wistar rats were divided into 4 groups: Group I - saline solution treated; Group II - antibiotic-treated; Group III - treated with larval debridement, and Group IV - without wound and treatment. Skin wounds were induced in groups I, II and III. All treatments were performed once and held for 48 h. Clinical, microbiological, histopathological, hematological, and biochemical analyses were done. Significant wound area contraction was found (>95%) in group III on day 9 compared to day 15 in group II. Complete elimination (0.0 ± 0.0 CFU/mL) of bioburden was achieved after the second treatment (day 6) in both the II and III groups, compared to an increase in Group I (6.51 ± 0.37 CFU/mL). A cleaner wound was also observed in the histopathological evaluation of group III, with adequate collagen formation and re-epithelialization on day 15. Furthermore, larvae increased blood platelet levels after the first treatment. L. cuprina larvae have proven safe and effective in accelerating wound treatment and eliminating MRSA.

Laktobasillerden elde edilen hücresiz süzüntülerin metisiline dirençli Staphylococcus aureus, vankomisine dirençli Enterococcus ve karbapeneme dirençli Klebsiella suşlarını inhibisyonu

Aim: Antibiotic resistance is a major health problem. Recently, probiotics are used in the field of alternative/supportive medicine. Thus, in this study, we aimed to evaluate the in vitro inhibitory effects of four different cell-free supernatants (CFSs) of lactobacilli species (L. fermentum, L. plantarum, L. acidophilus and L. rhamnosus) on clinically isolated Methicilin-resistant Staphylococcus aureus (MRSA) strains, Vancomycin-resistant Enterococcus (VRE) strains, and Carbapenem-resistant Klebsiella (CRK) strains. Materials and Methods: Lactobacillus strains were grown in de Man Rogosa Sharpe broth; after filtration, CFSs were diluted to obtain 25, 50, and 100% concentrations. Pathogen bacteria were grown in tryptic soy broth with and without CFSs in a micro-plate. The bacterial growths were measured using spectrophotometric method after four hours of incubation at 37°C. One-way ANOVA followed by Dunnett’s multiple comparisons and Kruskal-Wallis test were used for statistical analyses. Results: All tested CFSs at all concentrations were found to inhibit growth of MRSA, VRE, CRK strains; the results were found statistically significant (p&amp;lt;0.0001). At 50% concentrations, all CFSs were found to be most effective on MRSA growth. The CFSs of L.fermentum, L.acidophilus and L.plantarum were found to be most inhibitory at 50% concentration on VRE growth. 50% diluted CFSs of L.fermentum and L.plantarum were found to be effective on growth of CRK. All results were found statistically significant (p&amp;lt;0.0001). Conclusion: In our study, our results support that CFSs of lactobacilli strains inhibit growth of multi-drug resistant bacteria. Their inhibitory effects were dependent on microorganisms and CFS concentrations.

Hormones Can Influence Antibiotic Susceptibilities Even in Mono- and Co-Culture Conditions

Abstract Pseudomonas aeruginosa and Staphylococcus aureus are known as important nosocomial infectious agents also their co-infections are commonly seen in some patient groups. It is well known that host factors such as hormones have roles in modulation of growth, pathogenesis and susceptibilities to antimicrobials. In our study, the influences of norepinephrine (NE) and melatonin (MEL) on antibiotic susceptibilities were examined in mono and co-culture conditions. Methicilin resistant Staphylococcus aureus (MRSA) ATCC 43300 and Pseudomonas aeruginosa ATCC 27853 were investigated to determine the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of ciprofloxacin and gentamicin in the absence/presence of NE (0.0017 and 0.04μg/mL) and MEL (6 and 60 pg/mL) by microdilution method in mono and co-culture. It was found that hormones decreased (among 2-64 fold) MIC and MBC values of both antibiotics for MRSA. However, it was shown that hormones had no effect on MIC values of both antibiotics for P. aeruginosa. MIC and MBC values of both antibiotics for co-culture were found to be reduced compared to monoculture of MRSA; were found to be increased compared to monoculture of P. aeruginosa. Whereas, hormones decreased MIC values of both antibiotics in co-culture conditions. Our results suggest that both hormones decreased MIC values and it seems that hormones could influence antibiotic susceptibilities in a strain-dependent manner.

Endophytic actinobacteria of Hymenachne amplexicaulis from the Brazilian Pantanal wetland produce compounds with antibacterial and antitumor activities

The increase in the number of deaths from infections caused by multidrug-resistant bacteria and cancer diseases highlights the need for new molecules with biological activity. Actinobacteria represent a potential source of new compounds, as these microorganisms have already produced a great diversity of clinically employed antibiotics. Endophytes from unexplored biomes, such as the Pantanal (the largest wetland in the world), can be a source of new molecules. Hymenachne amplexicaulis is among the unexplored native plants of the Pantanal in terms of its endophytic community. This plant is considered a weed in other countries due to its ability to adapt and compete with native plants, and there is evidence to suggest that the endophytic community of H. amplexicaulis plays an important role in this competitiveness. To explore its therapeutic potential, the present study isolated, identified (using partial sequence of the 16S rDNA) and bioprospected H. amplexicaulis endophytic actinobacteria. Ten isolates belonging to the genera Streptomyces, Microbispora, Leifsonia, and Verrucosispora were obtained from root fragments. The susceptibility profile of the isolates to the different classes of antibiotics was evaluated, with 80 % of the isolates showing resistance to the antibiotics Nalidixic Acid, Ampicillin, Chloramphenicol, Oxacillin, and Rifampicin. To assess antibacterial and antitumor activities, methanolic extracts were obtained by fermentation in SG culture medium at 36 °C at 180 rpm for 10 days. The extract produced from the S. albidoflavus CMRP4854 isolate was the only one to show activity against the Gram-negative bacterium Acinetobacter baumanii. Due to the great clinical importance of this pathogen and the difficulty in obtaining active compounds against it, the CMRP4854 isolate should be further investigated for the identification of active compounds and mode of action. We also emphasize the results obtained by the extract of the isolates Streptomyces albidoflavus CMRP4852 and Verrucosispora sp. CMRP4860 that presented antibacterial effect against Methicilin-resistant Staphylococcus aureus (MRSA) (MIC: 1.5 μg/mL and 13 μg/mL, respectively) and Vancomycin-resistant Enterococcus (VRE) (MIC: 40 μg/mL for both extracts). Extracts (200 μg/mL) of these two endophytes also showed selective cytotoxicity action against murine B16-F10 melanoma cells. However, the CMRP4852 extract also affected the density of normal cells. Due to these results, the crude extract of isolate CMRP4860 Verrucosispora sp., which was the only one that presented cytotoxicity and reduced cell density only in tumor cells, was selected for subsequent analysis involving scale-up fermentation of the CMRP4860 resulting in 9 fractions that were tested against both bacteria and tumor cells, with particular fractions showing promise and meriting further investigation. Taken together, the results of this study not only show for the first time that the endophytic community of H. amplexicaulis actinobacteria can produce secondary metabolites that potentially possess important antibacterial and cytotoxic properties, but also reinforce the pressing need to conserve biomes such as the Brazilian Pantanal.

Risk Factors of Bacterial Resistance to Antibiotics in Internal Medicine and Hemodialysis Nephrology Services at the Edith Lucie Bongo Ondimba General Hospital

Introduction: Antibiotic resistance is a public health problem. It is due to multi-resistant bacteria (MRB). The objective of this study was to determine bacterial resistance to antibiotics in chronic renal failure at the Edith Lucie BONGO ONDIMBA general hospital (HGELBO). Patients, material and method: This was an analytical cross-sectional study conducted from January 1 to August 31, 2019 at the HGELBO. It concerned all patients admitted to the HGELBO with positive bacteriological samples. After a study of the sensitivity to isolated species, the patients were divided into two (02) groups: those MRB positive (+) and not MRB or negative (-). Epi Info software version 3.5.1 was used for the calculation of the rates and the comparison of the variables. The adjusted odds ratio (ORa) with a 95% confidence interval was used to measure the specific effect of each risk factor such as chronic kidney disease and diabetes, in order to rule out confounding factors. Multivariate analysis by binomial logistic regression was used. Results: There were 375 bacteriological samples from 258 patients, among them 247 patients with 235 positive samples or 63%. The eleven (11) are healthy patients. The median age was 33 with extremes ranging from 16 to 90. The female sex was predominant with a sex ratio of 0.6. The majority of MRB+ cases were found in internal medicine and nephrology with 12 cases (38.7%) and hemodialysis with 4 cases (12.9%). Urinary samples were in the majority with 74.5%. Escherichia coli was predominant in 30.3%. After studying the sensitivity to antibiotics of the 247 species included, 113 were MRB+ and 134 BMR- i.e. a frequency of 45.7%. Methicilin-resistant Staphylococcus aureus (MRSA) was predominant (51.3%). Multivariate logistic regression analysis showed that the main risk factor was antibiotic use (0Ra: 3.2 [1.9 - 5.4]; p-value S. aureus infection and male sex. Conclusion: Probabilistic antibiotic therapy leads to the selection of BMRs. Long hospital stays, male sex, and MRSA are risk factors or determinants of antibiotic resistance, but not chronic kidney disease.

Prevalence of multidrug-resistant bacteria colonisation among asylum seekers in western Switzerland.

The recent increase of migration to Europe represents a risk of increased the prevalence of multidrug-resistant (MDR) bacteria. We conducted a cross-sectional study among asylum seekers admitted at two hospitals in Switzerland. Of the 59 patients included, 9 (14%) were colonised by a MDR bacteria, including 5 (8.5%) methicilin-resistant Staphylococcus aureus (MRSA) and 4 (6.8%) extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae. No patient carried both ESBL-producing bacteria and MRSA. None of the patients carried a vancomycin-resistant Enterococcus (VRE) or a carbapenem-resistant Enterobacteriaceae (CRE). Colonisation with MDR bacteria was not associated with hospitalisation abroad or recent arrival in Switzerland. Whole genome sequencing analysis allowed us to exclude transmission between patients. The prevalence of MDR bacteria carriage is moderate among asylum seekers in western Switzerland. Further surveillance studies are necessary to determine if there is a risk of dissemination of pathogens into the local population.

In vitro antioxidant and antistaphylococcal properties of leaf extracts of Ocotea comorensis Kosterm (Lauraceae)

This study focused on the determination of phenolic compounds and the evaluation of the biological activity of Ocotea comorensis Kosterm (Lauraceae) extracts, an endemic and the only species of Ocotea genus from the Comoros archipelago. Leaf Extracts of O. comorensis were obtained by maceration in 50% hydro-methanol, acetone and cyclohexane. Their total phenolic and flavonoids contents were quantified and their antioxidant activity, determined by both the Ferric Reducing Power and the DPPH radical scavenging assays. The hydromethanolic extract (MEOc) exhibited the highest DPPH radical scavenging activity (IC50 = 9.28 ± 0.58 μg. mL−1) and the largest reducing capacity of ferrous ions. The most relevant contents in total phenolics (733.33 ± 20.272 µg Gallic Acid Equivalent. mg−1) and flavonoids (142.6 ± 8.20 μg catechin equivalent. mg−1) were also observed in the MEOc. Significant correlations were established between antioxidant activity and total phenolic and flavonoids contents. The antibacterial activity was carried out using microdilution method on Methicilin-Resistant Staphylococcus aureus (MRSA) isolates from burn wounds. The results revealed remarkable anti-MRSA activities with MICs ranging from 0.08 mg mL−1 to 13.41 mg.mL−1and the MEOc displayed the most important anti-MRSA activity. While this is the first study concerning extracts from O. Comorensis, our findings highlighted the richeness in phenolic compounds of these extracts and their great potential as source of antioxidants and antibacterial agents.

Green Synthesis of Zinc Nanoparticles Using Aqueous Extract of Magnoliae officinalis and Assessment of its Bioactivity Potentials

Today, considerable attention has been drawn to the unique physicochemical and biological properties of zinc nanoparticles. In this study, ZnO-NPs were synthesized using Magnoliae officinalis (MO) aqueous extract as a reducing and capping agent. Characteristics of ZnO-NPs were analyzed using analytical techniques such as UV, FTIR, SEM, XRD, EDX, DLS, and zeta potential. After that, the antibacterial activity of ZnO-NPs against methicilin resistant Staphylococcus aureus (MRSA) was studied. The results of FTIR and UV-vis spectra showed successful biosynthesis of ZnO-NPs, because the absorption peaks and functional groups involved in the synthesis process were well developed. Additionally, the SEM micrograph and the DLS showed that the morphology and size distribution of the ZnO-NPs were spherical with a size of 150 nm. XRD, EDX, and zeta potential indicated crystal form of ZnO-NPs with zinc: oxygen ratio of 72.35:27 and a surface charge of +28 mv. The antibacterial activity of ZnO-NPs with the assessment of the well-diffusion method, MIC and MBC indicated the highest inhibitory effect at a concentration of 300 µg/ml, MIC 250 µg/ml and MBC 300 µg/ml. As regards the desirable antimicrobial activity of biosynthesized ZnO-NPs using MO extract, they may be used for medicinal purposes, in particular as antimicrobials and antiseptic agents.

ANTIBACTERIAL ACTIVITY OF PARIJOTO FRUIT EXTRACT (Medinilla speciosa) ON BACTERIA EXTENDED SPECTRUM BETALACTAMASE (ESBL) ESCHERICHIA COLI AND METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS (MRSA)

Infection is one of the causes of death and pain that occurs mainly in Indonesia. Infections can be caused by Gram-negative and gram-positive bacteria such as the Extended Spectrum Beta Laktamase, Escherichia coli (E. coli) and Methicilin Resistant Staphylococcus aureus (MRSA), which are one of the Strain of S. aureus. The study aims to determine the antibacterial activity of Aquadest extracts, Methanol, Ethyl acetat and N-hexane of Parijoto (M. speciosa), MIC and MBC values against ESBL E. coli and MRSA bacteria. The samples in this study were Parijoto fruit extracts concentration 100 mg/mL . In this research antibacterial activity using the method of diffuse with the MHA media, while to know the value of MIC using methods dilution with MHB and MBC media using BAP media. The results were characterized by the formation of the largest barrier zone on the 11.6 mm methanol extract, the smallest MIC yield on N-hexane and aquadest extracts with a value of 50 mg/mL, whereas on MBC tests each extract resulted in a value of 50 mg/mL and While the hate zone against the MRSA bacteria is obtained the largest diameter of the hate zone in the N-hexane solvent, which is 23.17 mm in average, the largest MIC value in the aquadest solvent at a concentration of 50 mg/ml, and the largest MBC value in methanol solvent Concentrations of 50 mg/ml. So that it can be concluded Parijoto fruit extract has the potential as an alternative substitute for chemical antibiotics against MRSA bacteria whereas for bacteria ESBL E. coli has no potential as an alternative to antibiotic substitute. Keywords : Antibacterial, Escherichia coli, Methicilin Resistant Staphylococcus aureus, Medinilla speciosa

Individualized vancomycin dosage regimens in children

As a glycopeptide antibiotic, vancomycin is the first choice for treatment of methicilin-resistant staphylococcus aureus(MRSA)infection.Because of the metabolic individual difference, if children were given the dose according to the instruction, few patients can achieve the valley concentration as recommended in the guideline.So it′s necessary for optimizing individual vancomycin dosage regimen with the help of therapeutic drug monitoring(TDM)and population pharmacokinetics model-nonlinear mixed effect model(NONMEM), in order to realiz the combination of effect and safety.This article will introduce the population pharmacokinetics model of vancomycin in children and discuss about major parameters influencing vancomycin metabolism, including age, body mass index, renal function, health condition, and drug combination.With rational therapeutic drug monitoring and optimizing parameters of NONMEM, we hope to realize area under concentration-time curve/ minimum inhibit concentration(AUC/MIC)ratio ≥400, and to provide the reference for safe and rational pediatric dosage regimen. Key words: Vancomycin; Nonlinear mixed effect model; Area under concentration-time curve/ minimum inhibit concentration; Individualized treatment

Cobalt(II) complexes with 1,10-phenanthroline alone and mixed with cytoside: Synthesis and antibacterial activities

Cobalt can bind to a range of biomolecules forming complexes that are suitable for use in various biological applications. Different ligands could be used to tune the properties of cobalt compounds whose ligand exchange rates become close to those of cellular processes.  In this study, two complexes were synthesized from 1,10-phenanthroline alone as [Co(phen) 2 (H 2 O) 2 ]Cl 2 and from both 1,10-phenanthroline and cytoside as [Co(phen) 2 (Cyt)H 2 O]Cl. The synthesis was checked using halide test, conductance measurement as well as spectroscopic (AAS, FTIR, Uv-vis) analysis. In vitro antibacterial activities of the two metal complexes were tested against Staphylococcus aureu s, methicilin resistant staphylococcus aureus (MRSA), Streptococcus pneumoniae, Escherichia coli , Klebsiella pneumoniae and Shegella boydii. These complexes showed better activities than the commercially available control drugs (chloramphenicol and ciprofloxacin) against certain strains of bacteria. Better inhibition zones were exhibited by [Co(phen) 2 (Cyt)(H 2 O)]Cl on MRSA (4.8%) and E. coli (21.4%) than chloramphenicol. Likewise, 11.9% and 22.8% more zones of inhibition than ciprofloxacin were shown against MRSA and E. coli , respectively. On the other hand, [Co(Phen) 2 (H 2 O) 2 ]Cl showed 5.3% and 3.0% more zones of inhibition against S. aurous and S. boydii ,  respectively, better than ciprofloxacin.

A mechanistic approach to the in-vitro resistance modulating effects of fluoxetine against meticillin resistant Staphylococcus aureus strains

Emergence of methicilin resistant Staphylococcus aureus (MRSA) strains is a major cause of infirmity worldwide and has limited our therapeutic options against these pathogens. In this regard, the search for candidates with an antimicrobial activity, with a greater efficacy and a lower toxicity, is necessary. As a result, there is greater need to search for resistance modifying agents which, in combination with existing drugs, will restore the efficacy of these drugs. The antibacterial effect of fluoxetine was determined by a broth microdilution method (the M07-A9 method of the Clinical and Laboratory Standard Institute) and flow cytometry techniques in which the probable mechanism of action of the compound was also assessed. The isolates used in the study belonged to the Laboratory of Bioprospecting of Antimicrobial Molecules (LABIMAN) of the Federal University of Ceará. After 24 h, Methicillin-resistant Sthaphylococcus aureus (MRSA) strains showed fluoxetine MICs equal to 64 μg/mL and 128 μg/mL, respectively. Cytometric analysis showed that treatment with fluoxetine caused alterations to the integrity of the plasma membranes and DNA damage, which led to cell death, probably by apoptosis.