Clinical evaluation of direct drug sensitivity test for blood culture positive broths / 中华检验医学杂志

Objective:To evaluate the clinical performance of direct antimicrobial susceptibility test in blood culture-positive broth, and to provide a basis for optimizing the antibiotic use strategy in clinical bloodstream infection.Methods:A retrospective analysis was conducted on 780 blood culture-positive samples collected in Peking University People′s Hospital from May 2017 to December 2021. The direct antimicrobial susceptibility test was performed by disk diffusion method on blood culture-positive broth. The antimicrobial susceptibility breakpoints were in accordance with Clinical and Laboratory Standards Institute (CLSI) M100 S32 edition document.Results:In this study, a total of 331 strains of Gram-negative bacteria (139 strains of Escherichia coli, 79 strains of Klebsiella pneumoniae, 35 strains of Pseudomonas aeruginosa, 21 strains of Acinetobacter baumannii) and 396 strains of Gram-positive cocci (25 strains of Staphylococcus aureus, 316 strains of coagulase-negative staphylococci, 47 strains of Enterococcussp.) were collected, after excluding 53 cases with two or more isolates. Compared with the routine antimicrobial susceptibility test (AST), the rates of category agreement (CA), major error (ME), and very major error (VME) of Gram-negative bacteria were 86.0% (1368/1 591), 8.7% (139/1 591), and 0.5% (8/1 591), respectively. On the other hand, the CA%, ME%, and VME% of Gram-positive cocci were 89.2% (960/1 076), 7.5% (81/1 076), and 1% (11/1 076), respectively. Regarding the individual antimicrobial agents, the CA% of Escherichia coli was 16/17 for imipenem, 90.1% (109/121) for meropenem, and 70.8% (85/120) for cefepime. For Klebsiella pneumoniae, the CA% of was 10/13 for imipenem, 80.9% (55/68) for meropenem, and 80.3% (53/66) for cefepime. The CA% of meropenem in Pseudomonas aeruginosa and Acinetobacter baumannii were 96.0% (24/25) and 16/16. The CA% of linezolid and cefoxitin in Staphylococcus aureus were 100% (25/25) and 100% (24/24), respectively. The CA% of linezolid, cefoxitin and gentamicin in coagulase-negative staphylococci were 98.9% (269/272), 94.5% (277/293) and 71.6% (194/271) respectively. Finally, for Enterococcus sp., the CA% of vancomycin and ampicillin were 91.5% (43/47) and 94.7% (36/38), respectively. Conclusion:Compared with the conventional AST, the blood culture-positive broth direct AST exhibited high category agreement and low error rates for both Gram-negative bacteria and Gram-positive cocci, which can serve a rapid alternative for AST in cases of clinical bloodstream infection.

Antimicrobial activity of oregan and clove essential oils against some foodborne pathogens / Atividade antimicrobiona dos óleos essenciais de orégano e cravo frente a patógenos alimentares

The tendency to replace synthetic antimicrobials for natural ones in food industry and an increase in bacterial resistance to antibiotics resulted in a necessity to find new alternatives, and essential oils are emerging as promising substitutes for synthetic chemicals in food preservation. The objective of this work was to test the antimicrobial activity of oregano (OEO) and clove (CEO) essential oils over a range of bacteria, molds and yeast of importance as pathogens or food spoilage. The antimicrobial activity of oregano and clove essential oils were analyzed by disk diffusion method and broth microdilution test (MIC) of OEO and CEO were determined for each tested microorganism. OEO and CEO were evaluated in natura (IN) and after thermal processing (TP) at 120 o C for 5 min. Both OEO and CEO presented the same inhibition zones for IN and TP samples, for all tested microorganisms, indicating that these oils can be thermally processed maintaining their antimicrobial activity. For OEO and CEO, the more sensitive microorganisms were the fungi (Aspergillus niger, Penicillium citrinum and Candida albicans), followed by Staphylococcus aureus, Bacillus cereus and Methicillin - resistant Staphylococcus aureus (MRSA); the lowest antimicrobial activities were observed against Streptococcus mutans and Enterococcus faecalis. In general, OEO resulted in higher inhibition zones and lower MIC values for all tested microorganisms, suggesting that it was more effective as an antimicrobial agent than CEO (AU)

A preferência mundial para alimentos mais saudáveis e livres de aditivos químicos pelos consumidores, associada ao aumento da resistência bacteriana, resultaram na necessidade de medidas alternativas no setor de alimentos. Os óleos correspondem a antimicrobianos naturais e constituem uma classe emergente como substitutos dos produtos químicos sintéticos na conservação de alimentos. O objetivo deste trabalho foi avaliar a atividade antimicrobiana de óleos essenciais de orégano (OEO) e cravo (CEO ) frente a bactérias, fungos e leveduras de importância no setor de alimentos. OEO e CEO foram avaliados in natura (IN) e após processamento térmico (TP) a 120 o C por 5 minutos. Para avaliar a atividade antimicrobiana frente a cada microrganismo empregou-se o método de discodifusão e o teste de microdiluição em caldo (MIC). Tanto o OEO quanto o CEO apresentaram zonas de inibição semelhantes para amostras IN e TP, indicando que a atividade antimicrobiana desses óleos são resistentes a altas temperaturas. Os microrganismos mais sensíveis para ambos os óleos essenciais foram os fungos (Aspergillus niger, Penicillium citrinum e Candida albicans), seguidos por Staphylococcus aureus, Bacillus cereus e Staphylococcus aureus resistente à meticilina (MRSA). Já as cepas Streptococcus mutans e Enterococcus faecalis apresentaram uma maior resistência frente à atividade antimicrobiana dos óleos essenciais. Em geral, os maiores halos de inibição e menores valores de MIC foram obtidos quando empregado o OEO, sugerindo uma maior atividade microbiana do mesmo quando comparado ao CEO. (AU)

Sensibilidad a los antimicrobianos de aislamientos de Streptococcus equi subsp. equi de la provincia de Buenos Aires, Argentina / Antimicrobial susceptibility in isolates of Streptococcus equi subsp. equi from Buenos Aires province, Argentina

Streptococcus equi subsp. equi es el agente etiológico de la adenitis equina, una enfermedad infecciosa que afecta al tracto respiratorio superior y linfonódulos de cabeza y cuello de equinos. La terapia antimicrobiana tradicional incluye como antibiótico de primera elección a la penicilina G (PEN), a la que los estreptococos suelen ser sensibles. El objetivo de este trabajo fue estudiar el perfil de sensibilidad a distintos antimicrobianos de cepas de S. equi que circulan en la provincia de Buenos Aires, Argentina. Se estudiaron 92 aislamientos mediante el método de difusión con discos; los antimicrobianos evaluados fueron PEN, cefotaxima, eritromicina, tetraciclina, enrofloxacina (ENR), trimetroprima-sulfametoxazol (TMS), ciprofloxacina, clindamicina (CLI), estreptomicina (STR) y florfenicol. Se determinó la concentración inhibitoria mínima (CIM) de la PEN y de aquellos antimicrobianos frente a los cuales S. equi mostró resistencia o sensibilidad intermedia. Se obtuvieron altos porcentajes de sensibilidad a todos los antimicrobianos por el método de difusión y valores de CIM por debajo de los puntos de corte para PEN, TMS y CLI. Se identificaron cepas resistentes a ENR y STR, con CIM50, CIM9o y rangos de CIM por encima de los puntos de corte. Los resultados confirman que la PEN podría utilizarse empíricamente, ya que las cepas circulantes en Buenos Aires no mostraron resistencia a este antimicrobiano. Se enfatiza en la relevancia del uso racional de los antibióticos para lograr éxito terapéutico, evitar la cronicidad, la recidiva de infecciones y la aparición de resistencia.

Streptococcus equi subsp. equi is the etiologic agent of strangles, an infectious disease affecting the upper respiratory tract and head and neck lymph nodes of equines. Routine antimicrobial therapy includes penicillin (PEN) as antibiotic of first choice. Streptococci are usually susceptible to PEN and only a few antimicrobial studies had been performed. The aim of this work was to study the antimicrobial susceptibility profile of S. equi from Buenos Aires, Argentina. Ninety-two isolates were studied by the single disk method to PEN, cefotaxime, erythromycin (ERY), tetracycline, enrofloxacin (ENR), trimethoprim sulfamethoxazole (TMS), ciprofloxacin, clindamycin (CLI), streptomycin (STR) and florfenicol. Minimum inhibitory concentration (MIC) to PEN and antibiotics with resistance and intermediate susceptibility were tested. High percentages of susceptibility were obtained by the disk diffusion method and MIC values of PEN, TMS and CLI were found to be under the breakpoint values. Resistant strains of ENR and STR with MIC50, MIC90 and MIC ranges above breakpoints were identified. These findings confirm that PEN may be used empirically because resistant strains were not found in Buenos Aires. Emphasis is placed on the rational use of antibiotics to achieve therapeutic success, to prevent chronicity, recurrence of infections and the emergence of resistance.

Study on in vitro drug susceptibility test of biomembrane-producing Klebsiella pneumoniae / 国际检验医学杂志

Objective To study the difference of in vitro drug susceptibility test of biomembrane-producing Klebsiella pneumoni-ae to provide accurate drug reference for clinical treatment.Methods The drug susceptibility test was carried out in clinically isola-ted and screened16 strains of biomembrane-producing Klebsiella pneumoniae by K-B paper diffusion method ,and the results at 24 , 48 ,72 h were recorded.Then the strains were reproduced for several generations until not producing biofilm.Then the above opera-tions were taken again.Finally ,the results of twice drug susceptibility tests were performed the contrastive analysis.Results The mm number of inhibition zone of biomembrane-producing Klebsiella pneumoniae at 24 h had statistical difference compared with that at 48 ,72 h(P<0.05).Conclusion When the in vitro drug susceptibility test of biomembrane-producing Klebsiella pneumoniae is conducted by K-B paper diffusion method ,it is suitable to report the results after 48 h ,this has a certain reference value for pre-venting this bacterium.

Difference in antimicrobial susceptibility of common clinical pathogens to different ratios of cefoperazone/sulbactam antimicrobial disks / 中国感染控制杂志

Objective To understand the antimicrobial resistance of common clinical pathogens to antimicrobial disks containing different ratios of cefoperazone/sulbactam,so as to provide basis for rational application of cefoper-azone/sulbactam in clinic.Methods 1 141 pathogens isolated from clinical specimens in a hospital in the first half year of 2014 were collected,disk diffusion method was adopted to detect antimicrobial activity of two kinds of cef-operazone/sulbactam disks (70/35 μg and 75/75 μg).Results Of 1 141 pathogenic strains,675 (59.16%)were En-terobacteriaceae,447 (39.18%)were non-fermentative bacteria,and 19 (1 .66%)were other gram-negative bacilli. Resistance rates of pathogens to 70/35μg and 75/75 μg cefoperazone/sulbactam antimicrobial disks were as follows:extended-spectrumβ-lactamases(ESBLs)-producing Escherichia coli (n=221)were 7.69% and 2.26% respective-ly,ESBLs-producing Klebsiella pneumoniae (n=92)10.87% and 3.26% respectively,imipenem-resistant Acineto-bacter baumannii (IRAB,n=295)54.92% and 11 .19%respectively;there were significant differences in antimicrobial activity between two ratios of antimicrobial disks(P 0.05).Conclusion Antimicrobial activity of two different ratios of cefoperazone/sulbactam antimicrobial disks to ESBLs-producing Enterobacteriaceae and IRAB is different,attention should be paid to ratios of cefoperazone/sulbactam during the treatment ,so as to achieve the desired therapeutic effect.

Nosocomial candidiasis in Rio de Janeiro State: Distribution and fluconazole susceptibility profile

One hundred and forty-one Candida species isolated from clinical specimens of hospitalized patients in Rio de Janeiro, Brazil, during 2002 to 2007, were analized in order to evaluate the distribution and susceptibility of these species to fluconazole. Candida albicans was the most frequent species (45.4%), followed by C. parapsilosis sensu lato (28.4%), C. tropicalis (14.2%), C. guilliermondii (6.4%), C. famata (2.8%), C. glabrata (1.4%), C. krusei (0.7%) and C. lambica (0.7%). The sources of fungal isolates were blood (47.5%), respiratory tract (17.7%), urinary tract (16.3%), skin and mucous membrane (7.1%), catheter (5.6%), feces (2.1%) and mitral valve tissue (0.7%). The susceptibility test was performed using the methodology of disk-diffusion in agar as recommended in the M44-A2 Document of the Clinical and Laboratory Standards Institute (CLSI). The majority of the clinical isolates (97.2%) was susceptible (S) to fluconazole, although three isolates (2.1%) were susceptible-dose dependent (S-DD) and one of them (0.7%) was resistant (R). The S-DD isolates were C. albicans, C. parapsilosis sensu lato and C. tropicalis. One isolate of C. krusei was resistant to fluconazole. This work documents the high susceptibility to fluconazole by Candida species isolated in Rio de Janeiro, Brazil.

Speciation of clinically significant coagulase negative staphylococci and their antibiotic resistant patterns in a tertiary care hospital.

Background: Coagulase negative Staphylococci (CONS) are normal human microbiota and sometimes cause infections, often associated with implanted devices, such as joint prosthesis, shunts and intravascular catheters, especially in very young, old and immunocompromised patients. These infections are difficult to treat because of the risk factors and the multiple drug resistant nature of the organisms. The study is undertaken to speculate CONS isolates from various clinical samples and to determine antibiotic susceptibility pattern of CONS by Kirby Bauer disc diffusion method. Methods: A total of 134 clinically significant CONS isolated from pus, urine, blood, fluid, sputum, ear swabs, endotracheal tube, ophthalmic, semen and nail samples. These isolates initially identified by colony morphology, Gram staining, catalase test, slide coagulase test, tube coagulase test and mannitol fermentation. Speciation of CONS was done by novobiocin resistance test, urease activity, ornithine decarboxylase and aerobic acid production from mannose. Results: S. epidermidis is the most frequent isolate 62 (46.3%) followed by S. saprophyticus 38(28.4%), S. haemolyticus 27(20.1%), S. lugdunensis 3(2.2%). S. warneri 3(2.2%), S. cohinii 1(0.7%). Antibiotic susceptibility testing of the isolates showed maximum resistance to penicillin 128 (95.5%) and ampicillin118 (88%) followed by erythromycin 96 (71.6%), cefoxitin 89 (66.4%), gentamicin 33(24.6%), piperacillin & tazobactam 31(23.8%), amoxicillin & clavulanic acid 25 (18.7%), linezolid 23 (17.2%), levofloxacin 9 (6.7%), vancomycin & teicoplanin 2 (1.5%), tigecycline 1 (0.7%). Conclusion: S. epidermidis is the more common isolate identified and CONS are often resistant to multiple antibiotics (Penicillin, ampicillin) & glycopeptides have been considered as the drugs of choice for the management of infections caused by these organisms.

Isolation and speciation of genus candida in patients undergoing chemotherapy and radiotherapy for head and neck tumours.

Background: Fungal infections occur as a result of defect in the immune system. The use of wide-spectrum antibiotics, immunosuppressive therapy, HIV and an increasing incidence of diabetes are some of the causes that resulted in raising number of immunocompromised individuals, in the global scenario. Opportunistic fungal infections mainly oral candidiasis is common in patients undergoing chemotherapy (CT) or radiotherapy (RT) for Head & Neck tumors. Objectives: Isolation and speciation of Candida with antifungal susceptibility testing in patients undergoing CT and RT for Head and Neck tumors. Methods: Study group comprised of 100 saliva samples collected by oral rinse method, (50 chemotherapy and 50 radiotherapy) from inpatients of King George hospital, Visakhapatnam and 50 normal healthy individuals were taken as control group. Standard mycological tests for the Candida isolation, speciation and antifungal susceptibility were done. Results: In the study group out of the 100 patients, 38% were culture positive for Candida. The most commonly isolated species was C. albicans (60.5%) followed by non albicans species. Most of the candida species showed sensitivity to nystatin, amphotericin B, itraconazole and Ketoconazole. In control group 9 out of 50 samples (18%) were culture positive and all the isolates were Candida albicans. Conclusion: Increase in frequency of oral candidiasis in patients undergoing chemotherapy and radiotherapy was observed. The increase in positivity may be attributed to inadequate nutritional status and poor oral hygiene during chemotherapy and radiotherapy. Culture positivity is more in RT patients than in CT patients. Though C. albicans is the predominant isolate, non albicans species are also emerging. All the Candida species isolated from study group were sensitive to nystatin, amphotericin B, itraconazole and ketoconazole. In the study group all the Candida species were resistant to clotrimazole and fluconazole and in the control group all the C. albicans were sensitive to fluconazole.

Study on bacteriostatic activity and stability of pine bark Oligomeric Proantho Cyanidins / 中国生化药物杂志

Objective To study the bacteriostatic activity and stability of pine bark Oligomeric Proantho Cyanidins. Methods By the K-B disk diffusion method, spoilage bacteria as experiment strains, to study the inhibition effects of the pine bark Oligomeric Proantho Cyanidins and the antimicrobial stability under certain temperature, pH, and UV exposure time. Results Pine bark Oligomeric Proantho Cyanidins had significant inhibitory effect on Gram positive bacteria (Staphylococcus aureus and Bacillus Sukatilis), which had better inhibition effects in the media neutral, but temperature and UV had little influence on the antimicrobial effects. The minimum inhibitory concentration (MIC) of pine bark Oligomeric Proantho Cyanidins against Staphylococcus aureus and Bacillus Sukatilis were 12.5 and 6.25 mg/mL, respective. However, on Gram negative bacteria(Escherichia coli and Pseudomonas aeruginosa) there was no obvious inhibition effects. Conclusion The pine bark Oligomeric Proantho Cyanidins has significant inhibitory effect on Gram positive bacteria, the inhibitory effect is stronger in the range of pH 6-7 , and the temperature and UV had a little effect on its antibacterial action, which means that the antibacterial action of pine bark Oligomeric Proantho Cyanidins had good stability.

Study of susceptibility of candida species in patients with malignant tumors / 中国综合临床

Objective To evaluate the clinical application of disk diffusion method(ROSCO company of Denmark) for testing the susceptibility of candida species isolated from patients with cancer with the using broth microdilution method ((NCCLS) M27-A of America Committee for clinical laboratory standards) as the gold standard in order to find the better method for clinical laboratory.Methods Antifungal susceptibility (5-flucytosine,amphotericin B,fluconazole and itraconazole) of 78 strains of Candida species were tested both by ROSCO disk diffusion method and ATB FUNGUR2 broth microdilution method.The microdilution method NCCLS as the gold standard.The sensitivity,specificity,positive and negative predictive values of two methods was calculated.Results The Kappa value was reached to 0.89 in term of disk diffusion method for detecting susceptibility of candida to 5-flucytosine,amphotericin B,fluconazole and itraconazole,suggesting that no serious errors was seen in terms of sensitive and resistant another method.Of 78 strains of candida,they had the high susceptibility to 5-flucytosine,amphotericin B,which were 88.20％ and 89.17 ％.The lower susceptibility of 78 strains of candida was fluconazole and itraconazole (56.34％ and 52.12％).Candida glabrata and candida krusei were proved to suspect to four kinds of antifungal agents(90.95％,85.71％).And the lowest positivity was 67.50％ and 41.67％ regarding of candida glabrata and candida krusei.Conclusion The higher consistency was seen in terms of detecting candida susceptibility to antibiotics by disk diffusion method and microdilution method,suggesting disk diffusion method can replace microdilution method.In bur hospital,candida species are susceptibility to amphotericin B at the highest sensitivity and courtyard albicans at lower sensitivity.Antifungal agents works to candida albicans and lower inhibition rate to candida kruse.

Evaluation of the capability of four tests for identification of the in vitro susceptibility of tigecycline against Acinetobacter and Enterobacteriaceae isolates / 中华微生物学和免疫学杂志

Objective To evaluate the capability of four tests for identification of the in vitro suscepti-bility of tigecycline against Acinetobacter and Enterobacteriaceae isolates.Methods Disk diffusion test was per-formed to detect the sensitivity of 158 Acinetobacter and 339 Enterobacteriaceae isolates to tigecycline.The mini-mum inhibitory concentrations ( MICs) of tigecycline for non-sensitive isolates were detected by using broth dilu-tion method ( BDM) , MIC Test Strip ( MTS) and agar dilution method.The differences with antimicrobial sus-ceptibility among the four different methods were evaluated.Results Tigecycline showed good antibacterial ac-tivity against both non-sensitive Acinetobacter and Enterobacteriaceae isolates with most of the MIC50 values in the sensitivity range of (0.5-2) mg/L and all of the MIC90 values of 4 mg/L.The MIC50 and MIC90 values measured by BDM were respectively 1 mg/L and 4 mg/L.The sensitivity rates presented by the results of BDM were re-spectively 87.1%and 70.2%based on the standards made by Food and Drug Administration (FDA) and Euro-pean Committee on Antimicrobial Susceptibility Testing ( EUCAST) .Agar dilution method indicated that most of the MICs of tigecycline to Acinetobacter and Enterobacteriaceae isolates were two dilutions higher than those de-tected by BDM with essential agreement (EA) rate of 56.5%.Both the very major error (VME) and the major error (ME) values were 0 and the categorical agreement (CA) rate was 46.8%according to the FDA standard.The VME and CA values were 0.8% and 24.2% based on EUCAST standard.Compared with agar dilution method, MTS showed better results in determining the susceptibility of Acinetobacter and Enterobacteriaceae iso-lates to tigecycline with MIC50 and MIC90 values of 1.5 mg/L and 4 mg/L, which was similar to the capability of BDM.Referring to the FDA and EUCAST standards, the sensitivity rates were 83.1% and 21.0%, the CA rates was 81.5%and 29.8%, and the EA rate was 71.8%.Most of the results tested by MTS were one dilution higher than those by BDM.FDA standard showed better correlation than EUCAST standard.Disk diffusion method showed the ME, mE, VME and CA values were respectively 19.4%, 71.8%, 0 and 8.9%according to FDA standard.Conclusion Disk diffusion method, MTS and agar dilution method all showed differences with BDM in susceptibility testing.The capability of MTS was similar to that of BDM.The results evaluated by FDA standard were better than those by EUCAST standard.The in vitro susceptibility of bacteria to tigecycline could be tested by disk diffusion method using FDA standard for evaluation, and confirmed with MTS if isolates were resistance or intermediate strains.The BDM could be performed for further confirmation if necessary.

In vitro Screening of Herbal Extracts and Antibiotics against Bacteria Isolated from Fish Products at Retail Outlets.

Aims: Many studies have been conducted on the antibacterial activity of medicinal plants against human pathogens. However, a little has been done on fish pathogens. The aim of this research work was to isolate bacterial pathogens from spoiled fish leading to human diseases and compare the efficacies of selected antibiotics and medicinal herbal extracts against these infectious pathogens. Study Design: An experimental study. Place and Duration of Study: Biotechnology Lab, Department of Zoology, University of AJ&K, Muzaffarabad, Pakistan, between Feb 2011 and August 2012. Methodology: Bacterial pathogens Enterobacter amnigenus, Serratia odorifera, Salmonella Typhimurium and Shigella flexneri were isolated from spoiled fishes. Various extracts of seed and stem parts of medicinal plants including Cinnnamomum zylanicum, Cuminum cyminum, Syzygium aromaticum, Curcuma long Linn, Trachyspermum ammi and Momordica charantia (both seeds and green parts of Bitter gourd) against common fish associated bacterial pathogens by filter disc diffusion method. Results: The highest zone of inhibition was observed by Ciprofloxacin against S. Typhimurium (61 mm), whereas 55 mm by Gentamicin and 51 mm by Streptomycin against S. flexneri. However, Penicillin G, Ampicillin, and Amoxicillin had no effect on S. flexneri and E. amnigenus. The extracts of green part of M. charantia showed better results as compared to the seed extracts. Phytochemical screening of medicinal plants indicated that individual compounds viz., thyme from ajwain, ar-turmerone from turmeric, eugenol, taninns and flavonoids from clove have antimicrobial activities. Conclusion: Current study supports the traditional use of medicinal plants as antibacterial agents.

Evaluation of anti-bacterial and anti-oxidant potential of andrographolide and echiodinin isolated from callus culture of Andrographis paniculata Nees

Objective: To evaluate the anti-bacterial and anti-oxidant activity of andrographolide (AND) and echiodinin (ECH) of Andrographis paniculata. Methods:In this study, an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-diphenyl-2-picryl-hydrazyl (DPPH) assay, respectively. Structure elucidation was determined by electro-spray ionization-MSD, NMR (1H and 13C) and IR spectra. Results: AND was effective against most of the strains tested including Mycobacteriumsmegmatis, showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values against Staphylococcus aureus (100 μg/mL), Streptococcus thermophilus (350 μg/mL) Bacillus subtilis (100 μg/mL), Escherichia coli (50 μg/mL), Mycobacterium smegmatis (200 μg/mL), Klebsiella pneumonia (100 μg/mL), and Pseudomonas aeruginosa (200 μg/mL). ECH showed specific anti-bacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa at a concentration higher than 225 μg/mL. Both AND and ECH were not effective against the two yeast strains, Candida albicans and Saccharomyces cerevisiae tested in this study. Conclusion:This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH, and it may provide the scientific rationale for its popular folklore medicines.

Antibacterial activities of some plant extracts used in Indian traditional folk medicine

Objective:To evaluate the antibacterial activity of the leaf extracts of Cestrum diurnum, Ocimum sanctum, Carcica papaya, Solanum villosum, Vitex negundo, and Clerodendron inerme against two gram positive bacteria (Staphylococcus aureus MTCC 2940 and Bacillus subtilis MTCC 441) and two gram negative bacteria (Escherichia coli MTCC 739 and Pseudomonas aeruginosa MTCC 2453). Methods: The sensitivity of two gram positive and two gram negative pathogenic multi-drug resistant bacteria to extracts of leaves of six medicinal plants used as popular medicine in India was studied in vitro by the disk diffusion method and minimal inhibitory concentration (MIC). Results: All the bacterial strains were found to be sensitive to aqueous, n-hexane and ethanol extracts. But, it is evident that the organic extracts were comparatively more effective than aqueous extracts. Conclusions: It can be concluded that the leaf extracts of the six medicinal plants possess antibacterial activity against human pathogens.

Evaluation of antimicrobial properties of four plant extracts against human pathogens

Objective: To investigate the antibacterial activity of the extracts of Alternanthera philoxeroides (A. philoxeroides), Plumeria obtusa (P. obtusa), Polyalthia cerasoides (P. cerasoides) and Ixoraacuminate (I. acuminate) against human pathogens. Methods: Aqueous and chloroform: methanol (1:1) extracts of the dried leaf of A. philoxeroides, flowers of P. obtusa, fruits of P. cerasoides and flowers of I. acuminate were tested in vitro by the disk diffusion method against four bacterial strains, namely, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonasaeruginosa. Susceptibility of four reference bacterial strains to some antibiotics in nutrient agar was also tested. Minimal inhibitory concentration (MIC) values were determined and qualitative phytochemical analysis of the crude extract of the tested plant parts was done. Results: Both the aqueous and the chloroform: methanol (1:1) extracts of P. cerasoides showed the strongest activity, followed by flowers of P. obtusa, leaves of A. philoxeroides and flowers of I. acuminate. Aqueous extracts of all the plant parts appeared to have less antibacterial activity than the chloroform:methanol (1:1) extracts. The result of phytochemical analysis of the crude extract of the tested plants showed that flavonoid was absent from all plant parts whereas steroid was present in all tested plant parts. Conclusions: The results support that these plant extracts can be used for the treatment of bacterial diseases.

Antifungal Susceptibility Testing of Dermatophytes / 대한의진균학회지

BACKGROUND: A standardized reference method for dermatophytes in vitro susceptibility testing is lacking. However, with increasing variety of drugs available to treat dermatophytosis, the need for a reference method for dermatophytes testing has become apparent. OBJECTIVE: To evaluate a method of quantifying dermatophytes, the standards for broth microdilution method and evaluation of the availability of disk diffusion method in antifungal susceptibility testing for dermatophytes. METHODS: 14 Candida species (sp.), 30 Trichophyton(T.) mentagrophytes, 9 T. raubitschekii and 11 T. rubrum were tested for fluconazole susceptibility by the broth microdilution method and disc diffusion method. Candida sp. was tested according to National Committee for Clinical Laboratory Standards (NCCLS) M27-A and M44-A. Broth microdilution method for T. mentagrophytes, T. raubitschekii and T. rubrum was operated according to NCCLS M38-A. Disk diffusion method for T. mentagrophytes, T. raubitschekii and T. rubrum was tested refer to NCCLS M44-A. RESULTS: The disk diffusion method showed 50% correlation rate with the broth microdilution method for antifungal susceptibility testing for Candida species. The MIC reading point and incubation time of the broth microdilution method for T. mentagrophytes, T. raubitschekii and T. rubrum are Spec-50 and from 7, 6 and 9 days. Relation between the broth microdilution method and disk diffusion method for dermatophytes is poor. CONCLUSIONS: The good method for quantifying dermatophytes is using vortexing only or liquid nitrogen and homogenizer. Standards of MIC reading point and incubation time of microdilution method for dermatophytes are Spec-50 and from 6 to 9 days. It appears that the disk diffusion method is not recommended method for the antifungal susceptibility testing of dermatophytes.

Characteristic of Drug Resistance in Staphylococcus aureus / 中华医院感染学杂志

OBJECTIVE To investigate the drug resistance and the prevalence of inducible clindamycin resistance in clinical isolates of Staphylococcus aureus and evaluate the clinical value of cefoxitin disk diffusion method and oxacillin disk diffusion for detection of meticillin-resistant S.aureus(MRSA).METHODS Bacteria identification and susceptibility test were performed by VITEK-2 system and K-B disk method.The PBP2a was detected by latex agglutination and MRSA was identified by cefoxitin disk diffusion method and oxacillin disk diffusion.The inducible resistance of erythromycin to clindamycin was checked by D-test according to the standards of CLSI(NCCLS).The statistical analysis was performed by WHONET 5.4 and SPSS 13.0 software.RESULTS Resistant rate to penicillin and ampicillin was 98.9% and 100.0%,respectively.Vancomycin-resistant(VRE) or intermediate strains were not found.Of the 93 S.aureus isolates,MRSA and meticillin-sensitive S.aureus(MSSA) were 58(62.4%) and 35(37.6%),respectively.The resistant rate of MRSA to 11 antibiotics was higher than MSSA.The sensitivity and specificity of cefoxitin disk diffusion method were 98.3% and 97.1%,respectively,those of oxacillin disk diffusion were 75.9% and 94.3%.Of the 9 isolates resitant to erythromycin but susceptible to clindamycin,5(55.6%) showed inducible resistance to clindamycin.CONCLUSIONS Resistance of S.aureus is quite serious.Cefoxitin disc diffusion method is a simple and reliable method for the detection of MRSA.The inducible resistance of erythromycin to clindamycin in S aureus should be checked by D-test in clinical microbiology laboratory routinely.

Detection of Meticillin-resistant Staphylococci Mediated by mecA Gene Using Cefoxitin Disk Diffusion Method / 中华医院感染学杂志

OBJECTIVE To evaluate application of cefoxitin disk diffusion method in detecting meticillin-resistant staphylococci(MRS)mediated by mecA gene.METHODS The cefoxitin disk diffusion method,oxacillin disk(diffusion) method,oxacillin agar dilution test,VITEK automicroscan as well as PCR amplification were performed and compared simultaneously for detection of MRS,and VITEK automicroscan was used in testing MIC.(RESULTS)(Among) 96 strains of Staphylococcus(16 S.aureus and 80 coagulase-negative staphylococci strains),54 strains of MRS(2 S.aureus and 52 coagulase-negative staphylococci strains) were identified by oxacillin disk(diffusion) method,oxacillin agar dilution test and VITEK automicroscan,48 mecA-genes were identified by PCR amplification(2 S.aureus and 46 coagulase-negative staphylococci strains) which was the same as by cefoxitin disk diffusion method.CONCLUSIONS The(cefoxitin) disk diffusion method is highly consistent with mecA gene method,and a reliable one of screening and(identifying) MRS mediated by mecA gene.

The Trends of the Species and Antimicrobial Susceptibility of Bacteria and Fungi Isolated from Blood Cultures (1986-1996) / 대한임상병리학회지

BACKGROUND: Analysis of the species and antimicrobial susceptibility trend of bacterial and fungal isolate from blood can provide the clinicians with important informations for the treatment of the patients. METHODS: We analyzed the species and antimicrobial susceptibility trends of microorganisms isolated from blood cultures from 1986 to 1996 at Kyunghee Medical Center. Identification of organism was based on conventional methods or commercial kit systems. Antimicrobial susceptibility test was done by the NCCLS disk diffusion method. RESULTS: The positive blood culture was obtained from 3,559 patients. Among the patients 95.6% showed aerobic and facultative anaerobic bacteria, 0.9% anaerobes, and 3.6% fungi. Escherichia coli was isolated most frequently, followed by Coagulase-negative staphylococcus, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus, alpha- hemolytic Streptococcus and Serratia. The proportion of patients with E. coli decreased from 34.5% in 1986 to 22.1% in 1996, while that of S. aureus increased from 9.7% to 13.9%. Proportion of methicillin-resistant S. aureus and the third generation cephalosporin-resistant K. pneumoniae increased during the study period. CONCLUSIONS: We conclude that E. coli is the most common cause of bacteremia at Kyunghee Medical Center. The third generation cephalosporin-resistant K. pneumoniae and methicillin- resistant S. aureus are increasing in proportion.