Study on Inhibitory Activity of Dracocephalum moldavica Extracts to Clinical Pathogenic Bacteria and Its Bioin- formatics / 中国药房

OBJECTIVE：To study inhibitory activity of different extracts of Dracocephalum moldavica to clinical pathogenic bacteria，and to excavate its possible antibacterial mechanism. METHODS ：After extraction by 65％ ethanol and extraction by petroleum ether ，dichloromethane，ethyl acetate ，n-butanol，the different polar fractions of D. moldavica were obtained . Taking Klebsiella pneumoniae ，Staphylococcus aureus and other clinical multiple resistant pathogens as objects，the diameter of inhibition zone of different extraction fractions was measured by paper diffusion method ，and the antibacterial active fraction was screened. The minimal inhibitory concentration （MIC）of antibacterial active fraction to common clinical pathogens was determined by agar dilution method ；the growth curve of MRSA was drawn by turbidimetric method. The differentially expressed protein between antibacterial active fraction group and control group was screened by PEAK ® Q 8.5 software，and the gene ontology （GO）analysis and KEGG signaling pathway enrichment analysis were carried out by Blast 2 GO and KOBAS 3.0 online software. RESULTS ： Petroleum ether ，dichloromethane，ethyl acetate and n-butanol fraction of D. moldavica had no significant inhibitory effect on Gram-negative bacteria. The ethyl acetate fraction of D. moldavica had antibacterial activity in varying degrees against several kinds of Gram-positive bacteria as Staphylococcus aureus ，S. epidermidis；the diameter of inhibition zone was 10-16 mm，which was the active fraction. MICs of ethyl acetate fraction to S. aureus ，S. epidermidis and S. hominis were all 0.781 3 mg/mL；MIC to S. saprophyticus was 0.390 7 mg/mL；MICs to S. saprophyticus and standard strain of S. aureus were both 1.562 5 mg/mL. The 1， 2 times MIC of ethyl acetate could inhibit the growth of MRSA ，and the inhibitory activity increased with the increase of dose. A total of 300 differentially expressed proteins were screened （P＜0.01），of which 239 were up-regulated and 61 were down-regulated. The differentially expressed proteins were （No.81260478，No.816- mainly concentrated in cell sites such as cells ，cellular com- 60048） ponent，etc.，and in metabolic process such as cell process ， biological process and molecular functions such as catalytic activity，protein binding ，etc. They were mainly concentratedwang.zhanli@hotmail.com in microbial metabolism in different environments ，fructose and mannose metabolism signaling pathway （P＜0.05）. CONCLUSIONS ：The ethyl acetate fraction of D. Moldavica is the antibacterial active fraction ，and its activity may be related to the microbial metabolism and cell glycometablism.

Antibacterial Activity of Floral Petals of Some Angiosperms

The in vitro antibacterial assay was carried out against both Gram positive (B. cerus and S. aureus) and Gram negative (E. coli and K. pneumoniae) bacteria. Floral petals of 20 different species of plants were collected and tested for antibacterial activity. The result showed that the petals were active against both Gram positive and Gram negative. Out of 20 floral petals tested, 19 floral petals exhibited antibacterial activity against selected bacterial strains. The minimal inhibitory zone of floral petal discs against human pathogenic bacteria varies from 2 – 6 mm. Rosa carolina and Ruellia tuberosa showed significance inhibition zone for all the bacterial strains while Lantana camara does not show inhibition zone for any of these pathogenic bacteria.

Antibacterial activity of medicinal plant extracts against Ralstonia solanacearum (Smith) that causes bacterial wilt in hot pepper (Capsicum annuum L. )

This study was conducted to evaluate the in vitro antibacterial activity of some medicinal plants against Ralstonia solanacearum. Bioactive chemicals were extracted from Burcea antidysenterica, Eucalyptus citriodora, Justicia schimperiana, Lantana camara, Melia azedarach and Ricinus communis leaves using maceration method. The bioassay was evaluated by disc diffusion method. The pathogen was isolated from infected Capsicum annuum plants using Casamino acid-Peptone-Glucose agar (CPG) medium. The isolate was identified using cultural, biochemical characteristics, pathogenicity test and found to be R. solanacearum. The methanol extracts had different composition, percentage extract yield, antibacterial activity and relative percentage inhibition. Unlike others, extracts of E. citriodora and R. communis consisted of all the tested secondary metabolites. All species showed antibacterial activity except M. azedarach. Significant differences were recorded in antibacterial activity among species and test concentrations. The highest antibacterial activity and the lowest bacteriostatic and bactericidal concentrations were found from E. citriodora and R. communis extracts. The higher potency of E. citriodora and R. communis extracts suggested the potential of the two species as a biocide to control bacterial wilt. However, further in vivo studies on these species extracts are compulsory.

Study on differences in antibacterial activity of ethanol extracts from chicory roots and stems against Staphylococcus aureus and Enterococcus faecalis / 中国药理学通报

Aim: To analyze the antibacterial effects of 95% ethanol extract of chicory roots and stems from Xinjiang on Staphylococcus aureus and Enterococcus faecalis, and provide reference data for identifying the better antibacterial efficacy parts of chicory. Methods: The diameters of the inhibition zone of roots and stem extracts were determined by the Oxford Cup method; the minimum inhibitory concentrations (MIC) of roots and stem extracts on the bacteria were determined by the half - dilution method; the roots and stem extracts to observe the effects on bacterial proliferation were determined by the growth curve method; and the concentration of alkaline phosphatase (AKP) in bacterial extracellular solution enzyme was determined by labeling method. Results: The 95% ethanol extract of chicory roots and stems had significant inhibitory effects on the growth of Staphylococcus aureus and Enterococcus faecalis. Chicory roots' minimum inhibitory concentration to both bacteria was 64 g · L-1, and the minimum inhibitory concentration of chicory stems to both bacteria was 50g· L-1,64g· L-1, respectively. And the 95% ethanol extract of chicory stems had better inhibitory effect on Staphylococcus aureus, while the 95% ethanol extract of chicory roots had better inhibitory effect on Enterococcus faecalis; the ethyl acetate extract of chicory roots had better antibacterial effect on both bacteria than extract of 95% ethanol did (P <0. 01). Conclusions: The 95% ethanol extract of chicory roots and stems can significantly inhibit the proliferation of both bacteria, and the inhibitory effect of chicory stems on Staphylococcus aureus is more obvious, and the inhibitory effect of chicory roots on Enterococcus faecalis is better; the best antibacterial effect of chicory roots is ethyl acetate extraction.

Use of succinic & oxalic acid in reducing the dosage of colistin against New Delhi metallo-?-lactamase-1 bacteria

Background & objectives: New Delhi metallo-?-lactamase 1 (NDM-1) cleaves the beta-lactam ring, and confers bacterial resistance against most of the beta-lactam antibiotics, except tigecycline and colistin. Among these two antibiotics, colistin is considered toxic, and therefore, its clinical use and dosage need cautious approach. In the present study, six organic acids were screened individually and in combination of two acids for their effectiveness against NDM-1 Escherichia coli and a combination of colistin and oxalic or succinic acid was tested to find out the potential of combination therapy for reducing the dose of toxic colistin. Methods: Antibacterial activity of the organic acid and their combinations was tested by disc diffusion method against NDM-1 E. coli, and minimum inhibitory concentration (MIC) was determined by broth dilution method. Synergistic effect between organic acids and colistin was tested by checkerboard method. Results: Oxalic acid showed the highest zone of inhibition (15�mm) followed by succinic acid, tartaric acid, fumaric acid, citric acid and malic acid. The combination of two acids did not increase the zone of inhibition significantly. MIC was found to be the lowest with oxalic acid and succinic acid (320 ?g/ml). In the presence of 160 ?g/ml oxalic acid or succinic acid, MIC of colistin was reduced from 8 to 4 ?g/ml, indicating synergistic effect. Interpretation & conclusions: Our findings showed that combination therapy using colistin and oxalic acid or succinic acid might find safe clinical application of this antibiotic in controlling infections due to NDM-1 bacteria.

In vitro assessment of the synergism between extracts of Cocos nucifera husk and some standard antibiotics

Objective To evaluate the interactions between the crude extracts of Cocos nucifera (C. nucifera) and six front line antibiotics (ampicillin sodium salt, penicillin G sodium, amoxicillin, chloramphenicol, ciprofloxacin and tetracycline hydrochloride), against some bacterial pathogens linked with human infection. Methods The pulverized husk of C. nucifera was dissolved in 95% n-hexane and extracted using Soxhlet extraction method and sterile distilled water (aqueous). The antibacterial susceptibility of the crude extracts of C. nucifera was tested against environmental and clinical strains (6) obtained from the South African Bureau of Standards (SABS), Vibrio (6) and Listeria pathogens (6). The agar-well diffusion method was used for screening the extracts for their antibacterial activity. The minimum inhibitory concentration and minimum bactericidal concentration of the extracts were determined. Time-kill assay was used to evaluate bactericidal and/or bacteriostatic activity. The synergistic effect of the crude extracts and antibiotics was assessed and evaluated by adopting the checkerboard methods. Results With the time-kill assay, the highest bactericidal activity was observed on Vibrio fluvialis EL041 with a −5.6 ± 0.2 log

Exploration of Phytochemical and Antibacterial Potentiality of Anagallis arvensis L. Extract against Methicillin-Resistant Staphylococcus aureus (MRSA).

Context: Anagallis arvensis L. (Scarlet pimpernel) was used to treatment of several ailments in several countries. Objective: The aim of this study was to evaluate the in vitro antimicrobial activity of leaf methanolic extract of A. arvensis against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). Methods: In this study A. arvensis leaf was shade dried, powdered and extract was made by using methanol. The antimicrobial activity of methanolic extract was investigated against clinical isolates of MRSA by both the disc diffusion method and the microbroth dilution method. Results: The result of disc diffusion method showed that the plant extract recorded different degrees of antibacterial activity on MRSA as evidenced by the inhibited zones. The MICs of the plant extract and vancomycin were >100 and 14.5±0.1 μg/mL, respectively. This results showed that the plant extract although have slightly effect on MRAS but it was not sufficient strong. Discussion and Conclusion: A. arvensis leaf extract has anti-MRSA properties, corroborating the traditional therapeutic uses of this plant, and can be used in the therapy of infectious diseases as well as an antimicrobial supplement in food industries.

In vitro Activity of Garlic (Allium sativum) on Some Pathogenic Fungi.

Aim: This study was conducted to investigate the in vitro antifungal activity of garlic (Allium sativum) on some pathogenic fungi. Study Design: This is a comparative evaluation report on garlic as an antifungal agent. Place and Duration: Department of mycology, Veterinary Research institute, between June-October 2013. Methodology: Samples of garlic were obtained from a local market. It was thoroughly, cleaned, peeled and pulverized. Aqueous and organic extracts of garlic were obtained by maceration and Soxhlet extractor apparatus. The methanol and petroleum ether extracts were tested against Candida albicans, Aspergillus, Curvularia and some Dermatophyte species using cup diffusion and agar incorporated methods. Diameter of Inhibition zones of growth were measured in millimeter (mm) and expressed as Mean ±SD. Results: The obtained results revealed that aqueous and petroleum ether extracts possess the stronger activity and a broader fungicidal spectrum against tested fungi compared to methanol extract. The study also showed that the dry coarsely- powdered garlic was found to be more potent to Candida albicans than the commercial Nystatin. Conclusion: The study demonstrated the potent activity of garlic against tested fungi which encourages its use as a suitable alternative drug for controlling fungal infections because it has far less risk of side-effects than most known antifungal drugs and it can be used indefinitely in quite large amounts. Therefore, adding garlic to food (raw) or crushing and swallowing raw cloves which are cheaper is recommended as a powerful anti-fungal agent. Further purification and formulation of the garlic would give a true antifungal activity comparable to standard antibiotics.

Distribution of Methicillin-Resistant Staphylococcus aureus (MRSA) in Apparently Healthy Population and its Susceptibility to Saponins from Dialium guineense.

Aims: The ethanolic extracts of stem bark and fruit pulp as well as saponins from Dialium guineense were assayed for antibacterial activity against Gram positive and negative strains and clinical strains of methicilin resistant Staphylococcus aureus (MRSA) isolated from different locations on human body aged 20-30 years within the University of Nigeria community. Methodology: Agar diffusion technique was adopted. Results: The results showed that MRSA is predominant in apparently healthy population of the University community with 100% in males and 92.3% females showing positive case in nasal swab, 87.5% and 96.6 % positive from ear swabs of male and female volunteers respectively; and 77.7% positive from the high vaginal swabs of females. MRSA and other clinical isolates showed higher susceptibility to saponins compared to crude extracts; however, Bacillus cereus (NRRL 14724 and 14725) were not susceptible to the saponins from D. guineense. The MICs of the saponins were 31.25 mg/mL (B. subtilis ATCC 6051, P. aeruginosa, S. typhi, S. knitambo, P. mirabilis and S. aureus), 62.50 mg/mL (E. coli) and 125 mg/mL (P. aeruginosa ATCC 10145). Comparable MICs of higher values were obtained with the crude ethanolic extracts of stem bark and fruit pulp against MRSA and clinical isolates. Conclusion: The present findings revealed wide distribution of MRSA in an apparently healthy population in Nigeria and the susceptibility patterns showed the presence of a broad spectrum antibacterial agent in D. guineense.

In-vitro antidermatophytic activity of essential oil of Psidium guajava (Linn.).

Dermatophyte with the ability to digest keratine invade and therve on keratinized of human and animals. In the present study, the activity of essential oil of Psidium guajava (Linn.) was evaluated against four selected dermatophytes, namely Microsporiumcanis, Trichophytomruburum, T. verrucossum, T. tonsurans. Dermatophyteswere isolated with the infected skin, scalp, nail and genital organs of patients from districts hospital, Bareilly. Griseofulvin was used as a standard antifungal drug against the test dermatophytes. Oil was extracted through clevenger’s apparatus. Maximum inhibition zone was reported 69 mm against T. verrucossum followed by 60 mm Trichophytomruburum, 48 mm Trichophytomruburum and 45mm Microsporiumcanis. All five concentrations of oil showed excellent inhibitory effect against all test dermatophytes as compared to standard antifungal used.

In vitro Bioluminescence Used as a Method for Real-Time Inhibition Zone Testing for Antibiotic- Releasing Composites.

Aims: This study describes the potential of real-time bioluminescence imaging in evaluating the antibiotic efficiency of two cylinder-shaped bioabsorbable antibiotic-releasing composites by in vitro inhibition zone tests. The bacterial infections of bone tissue can cause extensive hard and soft tissue damage and decrease the efficiency of oral antibiotic therapy due to the poor blood circulation in the infected area. To overcome this problem, new, locally antibiotic-releasing biodegradable composites have been developed. Study Design & Methodology: The two composites evaluated in this study were composed of poly(L-lactide-co-ε-caprolactone) matrix, β-tricalcium phosphate ceramic and either ciprofloxacin or rifampicin antibiotic. The composites were tested with genetically modified model pathogens of osteomyelitis (Pseudomonas aeruginosa and Staphylococcus epidermidis) in vitro in inhibition zone tests using a method of real-time bioluminescence. Results: The first signs of the effect of the released ciprofloxacin or rifampicin became visible after four hours of incubation and were seen as changed bioluminescence around the composite pellet on a culture dish. Both of the composite types showed excellent effects against the sensor bacteria within the diffusion area. Bioluminescence measurements suggested that no survivor bacteria capable of evolving resistant strains were left inside the inhibition zones. The S. epidermidis bacterial strain was an inhibition sensor and P. aeruginosa was a stress sensor. Conclusion: These results highlight the potential of the composite materials against the pathogens of osteomyelitis. The approach allows continuous visual inspection of the efficacy of the antibiotics against the bacteria

In vitro antibacterial activity of leaf extracts of Zehneria scabra and Ricinus communis against Escherichia coli and methicillin resistance Staphylococcus aureus

Objective: To evaluate the antibacterial activities of the crude leaves extracts of Zehneria scabra (Z. scabra) and Ricinus communis (R. communis) against Escherichia coli (E. coli), Staphylococcusaureus (S. aureus) and methicillin resistance S. aureus. Methods: The crude powdered leaves of Z. scabra and R. communis were extracted successively by organic solvents in increasing polarity [benzene, chloroform:acetone (1:1), 70% alcohol and distilled water]. The antibacterial susceptibility of the crude leaves extracts of were tested against standard strains of E. coli (ATCC 25922) and S. aureus (ATCC 2923) and clinical isolates of E. coli, S.aureus and methicillin resistance S. aureus using agar well diffusion method. Results: In Z. scabra and R. communis leaf extracts, the most sensitive standard strain was S. aureus with an inhibition zone of (14.00±1.20) mm and (15.90±2.13) mm, respectively. The minimum inhibitory concentration (MIC) values of Z. scabra extracts against test organisms ranged from 1.95 mg/mL for extract 3 in clinical and standard strains of S. aureus to 250 mg/mL for extract 1 and 4 in clinical and standard strains of E. coli. The MIC values of R. communis extracts against test organisms ranged from 1.95 mg/mL for extract 2 and 3 standard strains of S. aureus to 250 mg/mL for extract 1 in clinical isolate of E. coli. Most of the minimum bactericidal concentration and MIC values of plant extracts were almost similar particularly in R. communis, or minimum bactericidal concentration equal to one dilution factor less than MIC value of the extracts mainly in Z. scabra. Conclusions: The potency of plant extracts against test organisms were depend on different organic solvents used. Clinical isolate of bacterial pathogens showed less zones of diameter compared to the standard strains. Gram-positive had wide inhibition zones than Gram-negative bacteria. Further studies should be carried out to isolate the pure compounds and standardization of the methods of plant extracts for an in vitro testing.

In vitro antibacterial activity of leaf extracts of Zehneria scabra and Ricinus communis against Escherichia coli and methicillin resistance Staphylococcus aureus

Objective: To evaluate the antibacterial activities of the crude leaves extracts of Zehneria scabra (Z. scabra) and Ricinus communis (R. communis) against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and methicillin resistance S. aureus. Methods: The crude powdered leaves of Z. scabra and R. communis were extracted successively by organic solvents in increasing polarity [benzene, chloroform:acetone (1:1), 70% alcohol and distilled water]. The antibacterial susceptibility of the crude leaves extracts of were tested against standard strains of E. coli (ATCC 25922) and S. aureus (ATCC 2923) and clinical isolates of E. coli, S. aureus and methicillin resistance S. aureus using agar well diffusion method. Results: In Z. scabra and R. communis leaf extracts, the most sensitive standard strain was S. aureus with an inhibition zone of (14.00±1.20) mm and (15.90±2.13) mm, respectively. The minimum inhibitory concentration (MIC) values of Z. scabra extracts against test organisms ranged from 1.95 mg/mL for extract 3 in clinical and standard strains of S. aureus to 250 mg/mL for extract 1 and 4 in clinical and standard strains of E. coli. The MIC values of R. communis extracts against test organisms ranged from 1.95 mg/mL for extract 2 and 3 standard strains of S. aureus to 250 mg/mL for extract 1 in clinical isolate of E. coli. Most of the minimum bactericidal concentration and MIC values of plant extracts were almost similar particularly in R. communis, or minimum bactericidal concentration equal to one dilution factor less than MIC value of the extracts mainly in Z. scabra. Conclusions: The potency of plant extracts against test organisms were depend on different organic solvents used. Clinical isolate of bacterial pathogens showed less zones of diameter compared to the standard strains. Gram-positive had wide inhibition zones than Gram-negative bacteria. Further studies should be carried out to isolate the pure compounds and standardization of the methods of plant extracts for an in vitro testing.

Combined antibacterial activity of stingless bee (Apis mellipodae) honey and garlic (Allium sativum) extracts against standard and clinical pathogenic bacteria

Objective:To investigate the synergic antibacterial activity of garlic and tazma honey against standard and clinical pathogenic bacteria. Methods:Antimicrobial activity of tazma honey, garlic and mixture of them against pathogenic bacteria were determined. Chloramphenicol and water were used as positive and negative controls, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration of antimicrobial samples were determined using standard methods. Results: Inhibition zone of mixture of garlic and tazma honey against all tested pathogens was significantly (P≤0.05) greater than garlic and tazma honey alone. The diameter zone of inhibition ranged from (18±1) to (35±1) mm for mixture of garlic and tazma honey, (12±1) to (20±1) mm for tazma honey and (14±1) to (22±1) mm for garlic as compared with (10±1) to (30±1) mm for chloramphenicol. The combination of garlic and tazma honey (30-35 mm) was more significantly (P≤0.05) effective against Salmonella (NCTC 8385), Staphylococcus aureus (ATCC 25923), Lyesria moncytogenes (ATCC 19116) and Streptococcus pneumonia (ATCC 63). Results also showed considerable antimicrobial activity of garlic and tazma honey. MIC of mixture of garlic and tazma honey at 6.25%against total test bacteria was 88.9%. MIC of mixture of garlic and tazma honey at 6.25%against Gram positive and negative were 100%and 83.33%, respectively. The bactericidal activities of garlic, tazma honey, and mixture of garlic and tazma honey against all pathogenic bacteria at 6.25%concentration were 66.6%, 55.6%and 55.6%, respectively. Conclusions: This finding strongly supports the claim of the local community to use the combination of tazma honey and garlic for the treatment of different pathogenic bacterial infections. Therefore, garlic in combination with tazma honey can serve as an alternative natural antimicrobial drug for the treatment of pathogenic bacterial infections. Further in vivo study is recommended to come up with a comprehensive conclusion.

Antibacterial activity of psidium guajava l. methanol leaf extract against plant pathogenic bacteria in the genera pectobacterium and xanthomonas.

The antibacterial activity of methanol leaf extract of Psidium guajava L. was performed on six plant pathogenic bacteria, namely Xanthomonas citri, Xanthomonas euvesicatoria, Xanthomonas oryzae, Xanthomonas oryzicola, Pectobacterium carotovorum and Pectobacterium chrysanthemi by cup-plate agar diffusion method. Different concentrations gave different range of means diameter inhibition zones where at concentrations o f 25, 50, 100 and 200 mg/ml, the range was 10.00±0.00 mm to 15.00±0.00 mm, 12.00±0.00 mm to 17.00±0.00 mm, 15.00±0.00 mm to 20.00±0.00 mm and 16.00±0.00 mm to 25.00±0.00 mm, respectively. X. oryzae gave the highest mean diameter inhibition zone when tested with all concentrations compared to the mean diameter inhibition zones of other plant pathogenic bacteria. The minimal inhibitory concentration (MIC) of the methanol extracts was performed by macrobroth dilution technique and the lowest concentration used that was still able to inhibit the bacterial growth was 0.391 mg/ml for X. oryzae.

In vitro antimicrobial screening of selected Indian medicinal plants.

We have examined antimicrobial activities of medicinal plants Abultilon indicum, Adenocalymma alliaceum, Carica papaya, Crotolaria laburnifilia, Croton bonplandianum, Derris scandens, Eichornia crassipes, Iopomea hispida, Moringa heterohylla, Peltophorum pterocarpum that have been popularly used as folk medicines. Scientific information on antimicrobial properties of various natural sources is still rather scarce. The antimicrobial activities of the organic solvent extracts on the various test microorganisms, including bacteria and fungi investigated using agar well diffusion technique. The length of inhibition zone was measured in millimeters from the edge of the well to the edge of the inhibition zone. Methanol extracts exhibited promising antimicrobial activity than chloroform and hexane extracts. The extracts from varies parts of plants were assessed in an effort to validate the medicinal potential of the herb. Our results showed plant extracts have significant levels of antimicrobial activity.

In Vitro Antagonistic Characteristics of Bacilli Isolates against Trichoderma spp. and Three Species of Mushrooms

Twenty isolates of Bacillus species obtained from livestock manure composts and cotton-waste composts were tested for their antagonistic effects in vitro against three green mold pathogens of mushrooms (Trichoderma harzianum, T. koningii, and T. viridescens). However, there exists a possibility Bacillus species may have antagonistic effects against mushrooms themselves, and thus the same 20 isolates were tested in vitro against three species of mushrooms (Flammulina velutipes, Lentinus edodes, and Pleurotus ostreatus). Of the 20 Bacillus species isolates tested, two inhibited mycelial growth of T. harzianum, seven that of T. koningii, and eight that of T. viridescens. Importantly, the bacterial isolates M27 and RM29 strongly inhibited mycelial growth of all the Trichoderma spp. isolates tested. The isolate M27 was subsequently identified as the most effective in inhibiting mycelial growth of all the Trichoderma species. Interesting results of the effect Bacillus isolates had upon the mushroom species followed. It was found that most Bacillus isolates except 5T33 at least somewhat inhibited mycelial growth of the three mushroom species or some of the mushrooms. Furhermore, the antagonistic effects of the bacterial isolates against the three species of mushrooms varied depending on the mushroom species, suggesting a role for mushroom type in the mechanism of inhibition. The bacterial isolates M27 and RM29 were identified as having the most antagonistic activity, inhibiting mycelial growth of all the Trichoderma spp. as well as mycelial growth of the three species of mushrooms. These results suggest that the bacterial isolates and their antagonistic effects on green mold pathogens should be further studied for their practical use for biological control of green mold in the growing room of the mushrooms.

Prevalence of Teicoplanin-resistant Staphylococci and Evaluation of the Disk Diffusion Test for Testing the Susceptibility of Staphylococci to Teicoplanin / 감염

BACKGROUND: Teicoplanin is a glycopeptide antimicrobial agent effective against methicillin-resistant staphylococci. Decreased susceptibility of staphylococci to glycopeptides has been increasing. Teicoplanin diffuses poorly in agar and therefore the correlation between the inhibition zone diameter and the minimal inhibitory concentration(MIC) is rather poor. The purpose of this study was to evaluate the prevalence of teicoplanin-resistant staphylococci and to assess the reliability of inhibition zone diameters for determining the susceptibility of staphylococci to teicoplanin by comparing the results of the agar dilution MICs. METHODS: From June to August 1997, 290 clinical isolates of staphylococci(77 coagulase negative staphylococci(CNS), 213 Staphylococcus aureus) were collected. The antimicrobial susceptibilities to teicoplanin were determined by inhibition zone diameter and the results were compared with the MICs determined by the agar dilution method. RESULTS: Among 77 CNS strains, 75(97.4%) were susceptible and 2(2.6%) were intermediate by agar dilution method and all 213 strains of S. aureus were susceptible to teicoplanin. There was a poor correlation(r=0.50) between the zone diameters of inhibition and agar dilution MICs. In comparison with the results of disk diffusion test and agar dilution MIC, eight (2.8%) out of 290 isolates showed discrepancies (major error rates : 0.3%, minor error rates: 2.4%). CONCLUSIONS: Two(2.6%) out of 77 strains of CNS and none of 213 S. aureus strains revealed decreased susceptibility to teicoplanin. And the inhibition zone diameter was less reliable in determining the susceptibility of staphylococci than MICs. Therefore, the more effective and convenient method is needed.

The bacteriostasis effect and the influences to copy accuracy of alginate impression material spatulated with bromogeramine / 重庆医科大学学报

0.05),respectively.Conclusion:Alginate impression material mixed with bromogeramine(0.40%) had some bacteriostatic effect on bacteria except pseudomonas aeruginosa,and it has no effect on the impression accuracy.It could be an ideal disinfection method for clinical use.

Study on bacteriostatic efficacy of alginate impression materials impregnated with bromogeramine / 重庆医科大学学报

Objective:To observe the bacteriostatic efficacy of bromogeramine of different concentrations made with potassium alginate impression materials.Methods:Based on the methods described in"Disinfection Technical Guidelines,2002 ed‘the second chapter-xxxx’"(Ministry of Public Health of the People’s Republic of China),the bacteriostatic efficacy was evaluated through measuring the size of inhibition zone formed by mixing bromogeramine with potassium alginate impression material.Results:Bromogeramine of any concentration had no effect on Pseudomonas aeruginosa.When the concentration of bromogeramine was above 0.4 mg/ml,the size of bacterio- static ring did not change.However,when the concentration increased to 0.05%,0.1%,0.2%,or 0.4%,the diameter of the inhibition zone was increasinly enlarged.Conclusions:Bromogeramine of certain concentration had some bacteriostatic effect on bacteria except pseudomonas aeruginosa.Besides,the bacteriostatic efficacy increased with the concentration increasing,but it did not change when the concentration of bromogeramine was above 0.4 mg/ml.