In vitro control of Staphylococcus aureus (NCTC 6571) and Escherichia coli (ATCC 25922) by Ricinus communis L.

Objective

To evaluate antibacterial activity of hot and cold ethanol and methanol leaf extracts of Ricinus communis L (R. communis) against Staphylococcus aureus (S. aureus) (NCTC 6571) and Escherichia coli (E. coli) (ATCC 25922).

Methods

Leaf powder of R. communis L. was extracted with hot (in Soxhlet) and cold ethanol and methanol, separately. The antibacterial activity of the extracts was determined by agar well diffusion and macro broth dilution methods. The extracts were also subjected to phytochemical analysis.

Results

All the four test extracts showed inhibition on both S. aureus and E. coli. Hot and cold ethanol extracts revealed significantly (P<0.05) higher inhibition on S. aureus than methanol extracts, and the hot ethanol extract had the lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values (5 mg/mL and 10 mg/mL, respectively). E. coli was highly inhibited by hot extracts of both ethanol and methanol with the MIC and MBC of 40 mg/mL and 80 mg/mL, respectively. Phytochemical analysis revealed the presence of saponins, cardiac glycosides, tannins, flavonoids and terpenoids in all test extracts.

Conclusions

This study demonstrates that the hot and cold methanol and ethanol extracts are potential sources for control of S. aureus and E. coli. Especially, the hot and cold extracts of ethanol are more inhibitive against S. aureus even at lower concentration. Further study is needed to identify the specific bioactive compounds, their mode of action and their nontoxic nature in vivo condition.     

169株金黄色葡萄球菌药敏结果分析

目的探讨金黄色葡萄球菌耐药特征,指导临床合理用药。方法使用美国BD公司PHOENIX100全自动细菌鉴定/药敏仪进行鉴定、K-B法药敏试验、B-内酰胺酶测试,并以“WHONET5”软件对数据进行分析处理。结果产B-内酰胺酶90株占53. 3%,MRSA占SA感染标本总数的60. 9%,MRSA耐药率介于8. 3%—95. 3%,本室未检出耐万古霉素、替考拉宁、呋喃妥因的菌株,耐药率低的抗生素有利福平、阿米卡星、氨苄西林/舒巴坦、阿莫西林/克拉维酸、头孢噻肟。耐药率高的有青霉素、苯唑青霉素、红霉素、SMZ、喹洛酮类等。结论金黄色葡萄球菌呈高度耐药性,万古霉素是治疗MRSA感染的首选抗生素,MRSA的耐药性应引起广泛关注。     

Antimicrobial drug resistance of Staphylococcus aureus in dairy products

Objective

To evaluate the prevalence of multidrug resistant Staphylococcus aureus (S. aureus) in dairy products.

Methods

Isolation and identification of S. aureus were performed in 3 dairy-based food products. The isolates were tested for their susceptibility to 5 different common antimicrobial drugs.

Results

Of 50 samples examined, 5 (10%) were contaminated with S. aureus. Subsequently, the 5 isolates were subjected to antimicrobial resistance pattern using five antibiotic discs (methicillin, vancomycin, kanamycin, chloramphenicol and tetracycline). Sample 29 showed resistance to methicillin and vancomycin. Sample 18 showed intermediate response to tetracycline. The other samples were susceptible to all the antibiotics tested.

Conclusions

The results provide preliminary data on sources of food contamination which may act as vehicles for the transmission of antimicrobial-resistant Staphylococcus. Therefore, it enables us to develop preventive strategies to avoid the emergence of new strains of resistant S. aureus.     

基于刃天青微平板法检测金黄色葡萄球菌对天然产物的敏感性

[目的] 以刃天青为检测试剂,评价大黄酸、棉子酚、盐酸小檗碱、兰雪醌、槲皮素5种天然产物对金黄色葡萄球菌的抑制作用。[方法] 比较刃天青浓度、菌悬液浓度、培养基种类和反应时间对吸光值的影响,优化刃天青的工作条件。刃天青法进行药敏性实验得到五种天然产物的最低抑菌浓度（MIC）,求得毒力回归方程、相关系数（R²）和半抑菌浓度（IC₅₀）。通过Z值判断刃天青显色法适用于高通量筛选药物的可行性。[结果] 当刃天青孔内终浓度为20μg/mL,培养基为LB,菌悬液浓度为5×10⁵CFU/mL,反应时间9h时适用于金黄色葡萄球菌的药敏性实验。刃天青显色法与微量肉汤法检测得到的五种天然产物的抑菌结果具有一致性。[结论] 五种天然产物均具有一定的抑菌活性。刃天青显色法具有准确性好、灵敏度高及高通量的特点,适用于天然产物抗菌活性的筛选。     

Antibacterial activity of the essential oils from the leaves of Eucalyptus globulus against Escherichia coli and Staphylococcus aureus

Objective

To examine the in vitro antimicrobial activities of essential oil of the leaves of Eucalyptus globulus (E. globulus).

Methods

The essential oils of this plant were obtained by the hydrodistillation method. The inhibitory effects of this essential oil were tested against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by using agar disc diffusion and dilution broth methods.

Results

The results obtained showed that essential oil of the leaves of E. globulus has antimicrobial activity against gram negative bacteria (E. coli) as well as gram positive bacteria (S. aureus).

Conclusion

The encouraging results indicate the essential oil of E. globulus leaves might be exploited as natural antibiotic for the treatment of several infectious diseases caused by these two germs, and could be useful in understanding the relations between traditional cures and current medicines.     

In-vitro antimicrobial activity of marine actinobacteria against multidrug resistance Staphylococcus aureus

Objective

To investigate the antibacterial activity of marine actinobacteria against multidrug resistance Staphylococcus aureus (MDRSA).

Methods

Fifty one actinobacterial strains were isolated from salt pans soil, costal area in Kothapattanam, Ongole, Andhra Pradesh. Primary screening was done using cross-streak method against MDRSA. The bioactive compounds are extracted from efficient actinobacteria using solvent extraction. The antimicrobial activity of crude and solvent extracts was performed using Kirby-Bauer method. MIC for ethyl acetate extract was determined by modified agar well diffusion method. The potent actinobacteria are identified using Nonomura key, Shirling and Gottlieb 1966 with Bergey''s manual of determinative bacteriology.

Results

Among the fifty one isolates screened for antibacterial activity, SRB25 were found efficient against MDRSA. The ethyl acetate extracts showed high inhibition against test organism. MIC test was performed with the ethyl acetate extract against MDRSA and found to be 1 000 µg/mL. The isolated actinobacteria are identified as Streptomyces sp with the help of Nonomura key.

Conclusions

The current investigation reveals that the marine actinobacteria from salt pan environment can be able to produce new drug molecules against drug resistant microorganisms.     

住院患者分离的金黄色葡萄球菌耐药率比较分析

目的　探讨不同科住院患者分离的金黄色葡萄球菌耐药率。方法　药物敏感性分析采用纸片扩散法 (K B法 ) ,用WHONET5软件分析结果 ;耐药率的显著性比较用 χ2 检验。结果　 2 0 0 1年共分离金黄色葡萄球菌 2 6 2 5株 ,其中内、外、儿科和ICU患者分离的金黄色葡萄球菌为 16 6 9株 ,占全部金黄色葡萄球菌的 6 3 6 %。标本主要来自痰、分泌物、脓、血液和伤口。儿科住院患者分离的金黄色葡萄球菌对苯唑西林、庆大霉素、克林霉素、环丙沙星、左氧氟沙星和氯霉素的耐药率分别为2 3 3%、16 1%、2 9 3 %、11 2 %、4 0 %和 14 4% ,显著低于内、外科和ICU分离菌株的耐药率 (P <0 0 0 1)。内、外科住院患者分离的金黄色葡萄球菌对苯唑西林、庆大霉素、克林霉素、环丙沙星和左氧氟沙星的耐药率明显低于ICU分离的菌株 (P <0 0 0 1)。结论　内、外科住院患者分离的金黄色葡萄球菌的耐药率低于ICU患者的耐药率。     

Nitric oxide mediated Staphylococcus aureus pathogenesis and protective role of nanoconjugated vancomycin

Objective

To test the survival of Staphylococcus aureus (S. aureus) inside lymphocyte that contributes to the pathogenesis of infection and possible anti-inflammatory and antioxidative effect of nanoconjugated vancomycin against in vivo S. aureus infection in a dose and duration dependent manner.

Methods

5×10⁶ CFU/mL vancomycin-sensitive S. aureus (VSSA) and vancomycin-resistive S. aureus (VRSA) were challenged in Swiss male mice for 3 days, 5 days, 10 days and 15 days, respectively. Bacteremia and inflammatory parameters were observed to evaluate the duration for development of VSSA and VRSA infection. 100 mg/kg bw/day and 500 mg/kg bw/day nanoconjugated vancomycin were administrated to VSSA and VRSA infected group for 5 days. Bacteremia, inflammatory parameters and oxidative stress related parameters were tested to observe the effective dose of nanoconjugated vancomycin against VSSA and VRSA infection. Nanoconjugated vancomycin was treated at a dose of 100 mg/kg bw/day and 500 mg/kg bw/day, respectively, to VSSA and VRSA infected group for successive 5 days, 10 days and 15 days. Bacteremia, inflammatory parameters and oxidative stress related parameters were observed to assess the effective duration of nanoconjugated vancomycin against VSSA and VRSA infection.

Results

The result revealed that in vivo VSSA and VRSA infection developed after 5 days of challenge by elevating the NO generation in lymphocyte and serum inflammatory markers. Administration with nanoconjugated vancomycin to VSSA and VRSA infected group at a dose of 100 mg/kg bw/day and 500 mg/kg bw/day, respectively, for successive 10 days eliminated bacterimia, decreased NO generation in lymphocyte, serum inflammatory markers and increased antioxidant enzyme status.

Conclusions

These findings suggest, in vivo challenge of VSSA and VRSA for 5 days can produce the highest degree of damage in lymphocyte which can be ameliorated by treatment with nanoconjugated vancomycin for 10 successive days.     

Incidence of Community-associated Methicillin-resistant Staphylococcus aureus Infections in a Regional Hospital

Background and Objective: Since the early 2000s, the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections among the community of people lacking known healthcare risk factors has increased. This MRSA infection is referred to as community-associated MRSA (CA-MRSA) infection and is distinct from hospital-associated MRSA (HA-MRSA) infection, which occurs among people with known healthcare risk factors. Understanding the epidemiology of CA-MRSA infections is critical; however, this has not been investigated in detail in Japan. Our objective was to investigate the incidence of CA-MRSA infections in a regional hospital.Patients and Methods: We investigated CA-MRSA isolates and infections in a rural regional hospital by reviewing medical records of one year. Infections were classified as CA-MRSA if no established risk factors were identified.Results: During 2008, 31 Staphylococcus aureus (S. aureus) isolates were detected in 29 unique patients, with 1 methicillin-sensitive S. aureus (MSSA) isolates obtained from 19 patients (66%) and MRSA obtained from 10 patients (34%). In the 10 patients with MRSA, the number of HA-MRSA and CA-MRSA cases were nine (32% of patients with S. aureus isolates) and one (3%), respectively. The patient with CA-MRSA was diagnosed with cellulitis due to CA-MRSA. All nine patients with HA-MRSA exhibited colonization.Conclusion: We observed a CA-MRSA case in a regional hospital in Japan, suggesting that incidence trends of CA-MRSA should be considered in future research and treatment.     

Antimicrobial activity of green tea extract against isolates of methicillin-resistant Staphylococcus aureus and multi-drug resistant Pseudomonas aeruginosa

Objective

To evaluate antibacterial activity of the Indonesian water soluble green tea extract, Camellia sinensis, against clinical isolates of methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA) and multi-drug resistant Pseudomonas aeruginosa (MDR-P. aeruginosa).

Methods

Antimicrobial activity of green tea extract was determined by the disc diffusion method and the minimum inhibitory concentration (MIC) was determined by the twofold serial broth dilutions method. The tested bacteria using in this study were the standard strains and multi-drug resistant clinical isolates of S. aureus and P. aeruginosa, obtained from Laboratory of Clinical Microbiology, Faculty of Medicine, University of Indonesia.

Results

The results showed that the inhibition zone diameter of green tea extracts for S. aureus ATCC 25923 and MRSA were (18.970±0.287) mm, and (19.130±0.250) mm respectively. While the inhibition zone diameter for P. aeruginosa ATCC 27853 and MDR-P. aeruginosa were (17.550±0.393) mm and (17.670±0.398) mm respectively. The MIC of green tea extracts against S. aureus ATCC 25923 and MRSA were 400 µg/mL and 400 µg/mL, respectively, whereas the MIC for P. aeruginosa ATCC 27853 and MDR-P. aeruginosa were 800 µg/mL, and 800 µg/mL, respectively.

Conclusions

Camellia sinensis leaves extract could be useful in combating emerging drug-resistance caused by MRSA and P. aeruginosa.     

Anti-microbial principles of selected remedial plants from Southern India

Objective

To examine the anti-bacterial activity of leaf extracts of Morus alba L. (Moraceae) and Piper betel L. (Piperaceae), and seed extracts of Bombax ceiba L. (Borabacaceae).

Methods

We have partially purified plant extracts by solvent extraction method, and evaluated the effect of individual fractions on bacterial growth using Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) bacterial strains.

Results

Compared with Morus and Bombax fractions, Piper fractions showed significant growth inhibition on all the three types of bacteria studied. The EtOAc-hexane fractions of Piper leaves exhibited significant anti-bacterial activity with minimum inhibitory concentrations (MIC) of 50 µg/mL culture against both gram-positive and gram-negative bacteria. The EtOAc-fractions I, II, and IV inhibited bacterial colony formation on soft agar in addition to growth inhibition. A combination treatment of piper fractions with ampicillin resulted in significant growth inhibition in E. coli and P. aeruginosa, and combination with anticancer drug geldanamycin (2µg/mL) showed selective growth inhibition against P. aeruginosa and S. aureus. Three major compounds, i.e., eugenol, 3-hexene-ol and stigmasterol, were primarily identified from Piper betel leaf extractions. Among the individual compounds, eugenol treatment showed improved growth inhibition compared with stigmasterol and 3-hexene-ol.

Conclusions

We are reporting potential anti-bacterial compounds from Piper betel against both gram-positive and gram-negative bacteria either alone or in combination with drug treatment.     

Effect of ethanolic extract of Ecballium elaterium against Staphylococcus aureus and Candida albicans

Objective

To evaluate the antimicrobial activity of ethanolic extract of Ecballium elaterium (E. elaterium) fruits alone against Staphylococcus aureus (S. aureus) strains and Candida albicans (C. albicans) strains, or in combination with penicillin against Staphylococcus areus strains.

Methods

Evaluation of the antimicrobial activity or synergy interaction was carried out using microdilution method.

Results

The results showed that ethanolic extract of E. elaterium fruits has antimicrobial activity against methicillin resistant S. aureus (MRSA), methicillin sensitive S. aureus (MSSA) and C. albicans. This extract showed a significant decrease in minimum inhibitory concentrations (MIC) of penicillin against both MRSA and MSSA strains. Fractional inhibitory concentration index (FIC) between penicillin and ethanolic extract of E. elaterium fruits against these test strains was less than 0.5.

Conclusions

This study suggests that ethanolic extract of E. elaterium fruits has antimicrobial activity against S. aureus and C. albicans and there is a possibility of concurrent use of penicillin and E. elaterium extract in combination in the treatment of infections caused by MRSA and MSSA strains. A wider study is needed to identify the effective components, the mode of action and the possible toxic effect in vivo of these ingredients.     

Isolation of a small molecule with anti-MRSA activity from a mangrove symbiont Streptomyces sp. PVRK-1 and its biomedical studies in Zebrafish embryos

Objective

The aim of the present study was to isolate the anti-MRSA (Methicillin Resistant Staphylococcus aureus) molecule from the Mangrove symbiont Streptomyces and its biomedical studies in Zebrafish embryos.

Methods

MRSA was isolated from the pus samples of Colachal hospitals and confirmed by amplification of mecA gene. Anti-MRSA molecule producing strain was identified by 16s rRNA gene sequencing. Anti-MRSA compound production was optimized by Solid State Fermentation (SSF) and the purification of the active molecule was carried out by TLC and RP-HPLC. The inhibitory concentration and LC₅₀ were calculated using Statistical software SPSS. The Biomedical studies including the cardiac assay and organ toxicity assessment were carried out in Zebrafish.

Results

The bioactive anti-MRSA small molecule A₂ was purified by TLC with Rf value of 0.37 with 1.389 retention time at RP-HPLC. The Inhibitory Concentration of the purified molecule A₂ was 30 µg/mL but, the inhibitory concentration of the MRSA in the infected embryo was 32-34 µg/mL for TLC purified molecule A₂ with LC₅₀ mean value was 61.504 µg/mL. Zebrafish toxicity was assessed in 48-60 µg/mL by observing the physiological deformities and the heart beat rates (HBR) of embryos for anti MRSA molecule showed the mean of 41.33-41.67 HBR/15 seconds for 40 µg/mL and control was 42.33-42.67 for 15 seconds which significantly showed that the anti-MRSA molecule A₂ did not affected the HBR.

Conclusions

Anti-MRSA molecule from Streptomyces sp PVRK-1 was isolated and biomedical studies in Zebrafish model assessed that the molecule was non toxic at the minimal inhibitory concentration of MRSA.     

Evaluation of berries of Phytolacca dodecandra for growth inhibition of Histoplasma capsulatum var. farciminosum and treatment of cases of epizootic lymphangitis in Ethiopia

Objective:To evaluate the berries of Phytolacca dodecundra(P.dodecandra) for its effect on Histoplasma cupsulatum var.farciminosum(HCF) and for the treatment of cases of epizootic lymphangitis(ELi.Methods:Samples were collected from un-ruptured nodules of cases of EL at Debre Zeit and Akaki(central Ethiopia).Mycologieal culture and isolation of HCF were performed at the Akliln Lemma Institute of Pathobiology.Phytochemical screening was done for n-butanol extract of P.dodecandra to delect alkaloids,saponins,phenolic compounds and flavonoids.The minimum inhibitory concentrations(MICs) and minimum fungicidal concentrations(MFCs) ol aqueous and n-butanol extracts of P.dodecandra against FICF were determined by agar dilution assay.For the in vivo trial.5%simple ointment was prepared from n-butanol extract and applied topically to 24(twelve early and twelve moderate) cases of F.L.Results:Phytochemical screening showed that n-butanol extract ol P.dodecandra was positive lor alkaloids.saponins and phenolic compounds but negative for flavonoids.The MFCs of n-butanol and aqueous extracts of P.dodecandra were(0.039%-0.078%) and(0.625%-1.250%),respectively.The MFCs of n-butanol and aqueous extracts of P.dodecandra were(0.078%t-0.156%)and(1.250%-2.500%),respectively.The MIC and MFC of ketoconazole(positive control) was(1.200×10~(-5)%-2.500×10~(-5)%) and(5.000× 10~(-5)%-1.000×10~(-4)%),respectively while growth was observed on free medium(negative control).From the total of 24 treated cases of EL,14(58.3%) responded lo treatment;however,10(41.7%) did not respond to treatment.There was no significant difference in the degree of response to treatment between early and moderate cases(χ~2=0.086:P=0.408.Conclusions:It can be concluded that n-butanol extract of P.dodecandra demonstrates antifungal effects while the aqueous extract shows no antifungal activity.     

Antimicrobial activities of the rhizome extract of Zingiber zerumbet Linn

Objective

To investigate antimicrobial effects of ethanolic extract of Zingiber zerumbet (Z. zerumbet) (L.) Smith and its chloroform and petroleum ether soluble fractions against pathogenic bacteria and fungi.

Methods

The fresh rhizomes of Zingiber zerumbet were extracted in cold with ethanol (4.0 L) after concentration. The crude ethanol extract was fractionated by petroleum ether and chloroform to form a suspension of ethanol extract (15.0 g), petroleum ether fraction (6.6 g) and chloroform soluble fraction (5.0 g). The crude ethanol extract and its petroleum ether and chloroform fractions were evaluated for antibacterial and antifungal activity against thirteen pathogenic bacteria and three fungi by the disc diffusion method. Commercially available kanamycin (30 µg/disc) was used as standard disc and blank discs impregnated with the respective solvents were used as negative control.

Results

At a concentration of 400 µg/disc, all the samples showed mild to moderate antibacterial and antifungal activity and produced the zone of inhibition ranging from 6 mm to 10 mm. Among the tested samples, the crude ethanol extract showed the highest activity against Vibrio parahemolyticus (V. parahemolyticus). The minimum inhibitory concentration (MIC) of the crude ethanol extract and its fractions were within the value of 128-256 µg/mL against two Gram positive and four Gram negative bacteria and all the samples showed the lowest MIC value against V. parahemolyticus (128 µg/mL).

Conclusions

It can be concluded that, potent antibacterial and antifungal phytochemicals are present in ethanol extract of Z. zerumbet (L).     

Comparative study on production,purification of penicillin by Penicillium chrysogenum isolated from soil and citrus samples

Objective

To explore various unexplored locations where Penicillium spp. would be available and study the production of penicillin from the isolated Penicillium spp. in different media with altered carbohydrate source.

Methods

The collected soil samples were screened for the isolation of Penicillium chrysogenum (P. chrysogenum) by soil dilution plate. The isolated Penicillium species were further grown in different production media with changes in the carbohydrate source. The extracted penicillin from various isolates was analyzed by HPLC for the efficacy of the product. Further the products were screened with various bacterial species including methicillin resistant Staphylococcus aureus (MRSA). And the work was extended to find the possible action on MRSA, along with characterization using other pathogens.

Results

From the various soil and citrus samples used for analysis, only the soil sample from Government General Hospital of Bangalore, India, and Sanjay Gandhi Hospital, Bangalore, India, showed some potential growth of the desired fungi P. chrysogenum. Different production media showed varied range of growth of Penicillium. Optimum production of penicillin was obtained in maltose which proved maximum zone of inhibition during assay. Characterization of penicillin on pathogens, like wild Escherichia coli strain, Klebsiella spp., and MRSA, gave quite interesting results such as no activity on the later strain as it is resistant. HPLC data provided the analytical and confirmation details of the penicillin produced. Accordingly, the penicillin produced from the soil sample of Government General Hospital had the high milli absorbance unit of 441.5 mAu compared with that of the penicillin produced from Sanjay Gandhi Hospital sample, 85.52 mAu. Therefore, there was a considerable change in quantity of the penicillin produced from both the samples.

Conclusions

The Penicillium spp. could be possibly rich in hospital contaminants and its environments. This research focuses on various unexplored sources of medical ailments, and also shows that the growth of penicillin is high in maltose rich media that could possibly enhance the growth.     

Characterization and phylogenetic analysis of novel polyene type antimicrobial metabolite producing actinomycetes from marine sediments: Bay of Bengal India

Objective

To isolate and indentify the promising antimicrobial metabolite producing Streptomyces strains from marine sediment samples from Andrapradesh coast of India.

Methods

Antagonistic actinomycetes were isolated by starch casein agar medium and modified nutrient agar medium with 1% glucose used as a base for primary screening. Significant antimicrobial metabolite producing strains were selected and identified by using biochemical and 16S rDNA level. Minimum inhibitory concentrations of the organic extracts were done by using broth micro dilution method.

Results

Among the 210 actinomycetes, 64.3% exhibited activity against Gram positive bacteria, 48.5 % showed activity towards Gram negative bacteria, 38.8% exhibited both Gram positive and negative bacteria and 80.85 % isolates revealed significant antifungal activity. However, five isolates AP-5, AP-18, AP-41 and AP-70 showed significant antimicrobial activity. The analysis of cell wall hydrolysates showed the presence of LL-diaminopimelic acid and glycine in all the isolates. Sequencing analysis indicated that the isolates shared 98.5%-99.8% sequence identity to the 16S rDNA gene sequences of the Streptomyces taxons. The antimicrobial substances were extracted using hexane and ethyl acetate from spent medium in which strains were cultivated at 30°Cfor five days. The antimicrobial activity was assessed using broth micro dilution technique. Each of the culture extracts from these five strains showed a typical polyene-like property. The lowest minimum inhibitory concentrations of ethyl acetate extracts against Escherichia coli and Curvularia lunata were 67.5 and 125.0 µg/mL, respectively.

Conclusions

It can be concluded that hexane and ethyl acetate soluble extracellular products of novel isolates are effective against pathogenic bacteria and fungi.