Clinical Isolates Of Bacteria Research Articles

Effects of storage time on the antimicrobial activities and composition of lemon grass oil

The composition and antimicrobial activities of fresh and stored essential oil of Cympobogon citratus (lemon grass oil) were studied. Three samples of steam distilled oil from the aerial parts of well grown plants collected before 12 noon in Ile-Ife, Nigeria between December and April of year 2004, 2011 and 2013 were screened. The first two oils were stored after extraction half-full in well closed amber colored bottles at 4°C and were screened along with the freshly extracted 2013 oil. Antimicrobial studies included Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) determinations against nine strains of type and clinical bacteria isolates and two fungi. Time-kill analysis was done at MIC concentrations. A total of eight, twenty and thirty-six constituents were identified by GC–MS, accounting for 95.25%, 85.92%, and 93.07% in the fresh, two-year and nine-year old oil respectively. Geranial (51.70%), neral (32.62%) and nerol (4.40%) were the major constituents in the fresh oil while geranial (18.19%), neral (10.58%), 3-heptanol-4-methyl (10.50%), epoxy-linalooloxide (5.57%) and trans-7-oxabicyclo [4.3.0] nonane (6.75%) were those of the two-year old oil. Major constituents in the nine-year old oil include 1,6-octadien-3-ol, 3,7-dimethyl—(32.36%), geraniol (16.03%) and eucalyptol (10.81%). The MIC and MBC of the two stored oil were similar. The minimum antibacterial MIC:MBC of the fresh and the stored oils was 0.625%v/v:1.25%v/v and 1.25%v/v:10.0%v/v respectively. Pseudomonas aeruginosa was not inhibited by any of the three oil samples. Antifungal activities were higher in the stored oils. The nine year old oil killed the Staphylococcus aureus and Klebseilla pneumoniae strains faster than the fresh oil. In conclusion, there were extensive differences in the chemical constituents of fresh and stored lemon grass oil which affects its antimicrobial activities. Storage of the oil made available many components that were not found in the fresh oil.

Antibacterial and anti-biofilm activities of melittin and colistin, alone and in combination with antibiotics against Gram-negative bacteria

In vitro antibacterial and anti-biofilm activities of antimicrobial cationic peptides (AMPs) – melittin and colistin – both alone and in combination with antibiotics were evaluated against clinical isolates of Gram-negative bacteria. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) index were determined by the microbroth dilution and chequerboard techniques, respectively. The time-kill curve (TKC) method was used for determining the bactericidal activities of AMPs alone and in combination. Measurements of anti-biofilm activities were performed spectrophotometrically for both inhibition of attachment and 24-hour biofilm formation at MIC or subMIC. According to MIC90 values, the most active agents against Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae were colistin, imipenem and ciprofloxacin, respectively. In combination studies, synergistic effects were mostly seen with colistin–imipenem against E. coli and K. pneumoniae (50 and 54%, respectively), colistin–ciprofloxacin against P. aeruginosa (77%). In TKC studies, synergism was observed with almost all expected combinations, even more frequently than chequerboard method. All of the antimicrobial agents were able to inhibit attachment and 24-hour biofilm formation between 0–57% at 1/10 × MIC and 7–73% at 1 × or 1/10 × MIC, respectively. AMPs seem to be a good candidate for antimicrobial chemotherapy with their antibacterial and anti-biofilm activities as a single agent or in combination with antibiotics.

Emergence of ciprofloxacin-resistant extended-spectrum β-lactamase-producing enteric bacteria in hospital wastewater and clinical sources

This study aimed to evaluate the incidence of ciprofloxacin-resistant extended-spectrum β-lactamase (ESBL)-producing enteric bacteria in hospital wastewater and clinical sources. Enteric bacteria, mainly Escherichia coli, were isolated from clinical sources (urinary tract and gastrointestinal tract infections; 80 isolates) and hospital wastewater (103 isolates). The antibiotic resistance profile and ESBL production of the isolates were investigated by disc diffusion assay and combined disc diffusion test, respectively. Plasmid profiling was performed by agarose gel electrophoresis, and elimination of resistance markers was performed by a plasmid curing experiment. Antibiotic susceptibility testing revealed a high incidence of β-lactam resistance, being highest to ampicillin (88.0%) followed by amoxicillin, ceftriaxone, cefpodoxime, cefotaxime, aztreonam, cefepime and ceftazidime. Among the non-β-lactam antibiotics, the highest resistance was recorded to nalidixic acid (85.7%). Moreover, 50.8% of enteric bacteria showed resistance to ciprofloxacin. Among 183 total enteric bacteria, 150 (82.0%) exhibited multidrug resistance. ESBL production was detected in 78 isolates (42.6%). A significantly higher incidence of ciprofloxacin resistance was observed among ESBL-producing enteric bacteria both in clinical (P=0.0015) and environmental isolates (P=0.012), clearly demonstrating a close association between ESBL production and ciprofloxacin resistance. Plasmid profiling of selected ESBL-positive strains indicated the presence of one or more plasmids of varying sizes. Plasmid curing resulted in loss of ciprofloxacin and cefotaxime resistance markers simultaneously from selected ESBL-positive isolates, indicating the close relationship of these markers. This study revealed a common occurrence of ciprofloxacin-resistant ESBL-producing enteric bacteria both in hospital wastewater and clinical sources, indicating a potential public health threat.

Detection of Carbapenem Resistant Gram-Negative Bacteria in Clinical Isolates from a Tertiary Care Hospital

Carbapenem resistance is one of the major threats faced in antimicrobial treatment of infections caused by Gram negative organisms. In India and throughout the world the use of carbapenems has increased resulting in an increased resistance of pathogens to this class of antibiotics. Bacteria are capable enough to become resistant to antibiotics by a number of mechanisms both intrinsic and acquired, most common of which include enzymatic degradation of antibiotics. Carbapenem resistant Gram-negative bacteria usually spreads in the hospital settings to other patients and caregivers or relatives by unwashed hands or from contact with soiled equipment and surfaces such as bedrails, tables, chairs, countertops and door handles. These carriers are the ultimate sources of dissemination in the community. Detection of carbapenems is a crucial infection control issue because they are often associated with extensive antibiotic resistance, treatment failures and infection-associated mortality. The present study was undertaken to determine Carbapenem resistant Gram-negative bacteria in clinical isolates from a tertiary care hospital.

Detection of Carbapenem Resistant Gram-Negative Bacteria in Clinical Isolates from a Tertiary Care Hospital

Detection of Carbapenem Resistant Gram-Negative Bacteria in Clinical Isolates from a Tertiary Care Hospital

Antimicrobial Activities of Methanol, Ethanol and Supercritical CO2 Extracts of Philippine Piper betle L. on Clinical Isolates of Gram Positive and Gram Negative Bacteria with Transferable Multiple Drug Resistance.

Piper betle L. has traditionally been used in alternative medicine in different countries for various therapeutic purposes, including as an anti-infective agent. However, studies reported in the literature are mainly on its activities on drug susceptible bacterial strains. This study determined the antimicrobial activities of its ethanol, methanol, and supercritical CO2 extracts on clinical isolates of multiple drug resistant bacteria which have been identified by the Infectious Disease Society of America as among the currently more challenging strains in clinical management. Assay methods included the standard disc diffusion method and the broth microdilution method for the determination of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentrations (MBC) of the extracts for the test microorganisms. This study revealed the bactericidal activities of all the P. betle leaf crude extracts on methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), extended spectrum β-lactamase-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, and metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter baumannii, with minimum bactericidal concentrations that ranged from 19μg/ml to 1250 μg/ml. The extracts proved to be more potent against the Gram positive MRSA and VRE than for the Gram negative test bacteria. VRE isolates were more susceptible to all the extracts than the MRSA isolates. Generally, the ethanol extracts proved to be more potent than the methanol extracts and supercritical CO2 extracts as shown by their lower MICs for both the Gram positive and Gram negative MDRs. MTT cytotoxicity assay showed that the highest concentration (100 μg/ml) of P. betle ethanol extract tested was not toxic to normal human dermal fibroblasts (HDFn). Data from the study firmly established P. betle as an alternative source of anti-infectives against multiple drug resistant bacteria.

Characterization of integrons and novel cassette arrays in bacteria from clinical isloates in China, 2000-2014.

Rapid dissemination of antibiotic resistance genes among bacterial isolates is an increasing problem in China. Integron, a conserved DNA sequence, which is carried on episomal genetic structures, plays a very important role in development of antibiotic resistance. This systematic analysis was based on MEDLINE and EMBASE databases. We summarized the distribution and proportion of different types of gene cassette arrays of integrons (including class 1, 2, 3 and atypical class 1 integron) from clinical bacteria isolates in China. Fifty-six literatures were included in this study. Most of the strains were Gram-negative bacteria (94.1%, 7,364/7,822) while only 5.9% strains were Gram-positive bacteria. Class 1 integrons were detected in 54.2% (3956/7295) Gram-negative strains. aadA2 was the most popular gene cassette array detected from 60 Gram-positive bacteria while dfrA17-aadA5 were detected in 426 Gram-negative bacteria. This study identified 12 novel gene cassette arrays which have not been previously found in any species. All the novel gene cassette arrays were detected from Gram-negative bacteria. A regional characteristic of distribution of integrons was presented in this study. The results highlight a need for continuous surveillance of integrons and provide a guide for future research on integron-mediated bacteria resistance.

Novel platform technology to allow direct grafting of antimicrobial agents onto implantable metals.

Event Abstract Back to Event Novel platform technology to allow direct grafting of antimicrobial agents onto implantable metals. Felicity De Cogan1, Olachi Anuforom1, Anna F. Peacock2 and Ann Logan1 1 University of Birmingham, Institute of Infection and Ageing, United Kingdom 2 University of Birmingham, School of Chemistry, United Kingdom Introduction: The current management of microbial infection in injured tissues is by the systemic administration of antibiotic drugs. These are designed to eliminate pathogens while leaving the patient unharmed. This method is of limited efficacy as systemic antibiotics are not targeted to the site of infection and will often have poor penetration to areas around wounds and implants. The widespread use of prophylactic antibiotics has also led to increasing microbial resistance. Biomaterial solutions to target implant infections rely heavily on introducing an initial coating such as a polymer onto the metal, which then allows antibiotic agents to be included onto an implant surface. The antimicrobial agent can then either leach from the polymer or be covalently attached to the polymer. While this methodology is well established there are two significant drawbacks. Firstly, the inclusion of coatings such as polymers onto the surface of metal implants can hinder the osseointegration of the implant. Secondly, the leaching of materials gives sustained release over several months yet only tend to last for months. The majority of joint infections occur at greater than one year, this means these biomaterials don’t address the real unmet clinical need. In this work we report a novel attachment method which allows attachment of novel antimicrobial peptides directly to a metal surface. This grafting method also remains on the surface for extended periods of time (>1 year). Materials and Methods: Titanium was plasma nitrided at 440 °C for 19 hours. The metals were then washed using acetone to clean the surface. The surfaces were functionalised in N,N-dimethylformamide (DMF) using antimicrobial peptide (100µg), HBTU (0.5mM in DMF) and DIEA ( 60% v/v in DMF). The surfaces were washed extensively to remove unreacted material and then tested for efficacy at inhibiting bacterial growth against a range of bacteria and fungi. Lab strains were used initially, and multi-resistant clinical isolates later. Results: The peptides showed broad spectrum activity against a range of bacteria including lab strains and clinical isolates of both Gram positive and Gram negative bacteria. Peptides were tested for inhibition of growth in solution and their ability to prevent bacterial growth on the metal surfaces. Peptide coated titanium designed for orthopaedic implants showed significant reductions in the number of bacteria in solution around the surface with bacteria numbers reduced from 1x1012 to 1x103. The peptide coating also completely inhibited growth of bacteria on the surfaces (Figure 1). Conclusions: We have demonstrated the efficacy of our novel coating technology to both reduce bacterial load in solution around an implant and prevent bacteria creating a biofilm on the implant surface. We believe this has great potential to revolutionise implant materials and reduce the rate of implant associated infections. NIHR SRMRC for funding Keywords: Bacteria, Infection, Implant, bioactive interface Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Anti-infective biomaterials Citation: De Cogan F, Anuforom O, Peacock AF and Logan A (2016). Novel platform technology to allow direct grafting of antimicrobial agents onto implantable metals.. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00052 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Felicity De Cogan Olachi Anuforom Anna F Peacock Ann Logan Google Felicity De Cogan Olachi Anuforom Anna F Peacock Ann Logan Google Scholar Felicity De Cogan Olachi Anuforom Anna F Peacock Ann Logan PubMed Felicity De Cogan Olachi Anuforom Anna F Peacock Ann Logan Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Antimicrobial activity of some seaweeds species from Red sea, against multidrug resistant bacteria

This study evaluates the antibacterial activity of diethyl ether, methanol, ethanol and chloroform extracts of red algae Ceramium rubrum (Rhodophyta), Sargassum vulgare, Sargassum fusiforme and Padina pavonia (Phaeophyta) collected from Red sea, Egypt. The algal extracts were tested for their antibacterial activity against ten multidrug resistant clinical isolates of Gram positive and Gram negative bacteria. The highest inhibition activity among all extracts was obtained with 100μl diethyl ether extract S. fusiforme against Staphylococcus aureus 2 and 50μl ethanol extract of S. vulgare against Klebsiella pneumoniae. The algal extract of S. fusiforme and S. vulgare was characterized by Gas chromatography–mass spectrometry (GC–MS). The compounds with antimicrobial activity were identified, such as phenols, terpenes, acetogenins, indoles, fatty acids and volatile halogenated hydrocarbons. Transmission electron microscopy was applied for determining the morphological changes in S. aureus 2 and K. pneumonia treated with 100μl diethyl ether extract of S. fusiforme and 50μl ethanol extract of S. vulgare, respectively. Perforation of cell wall, leakage of cytoplasmic contents, severe distortion of outer cell shape, inner chromatin mild scattered cytoplasmic vacuolation, rupture of cell wall, and decreased cell size for both bacterial isolates treated with 100μl diethyl ether of S. fusiforme extract and 50μl S. vulgare ethanolic extract were recorded.

Antimicrobial evaluation of quaternary ammonium polyethyleneimine nanoparticles against clinical isolates of pathogenic bacteria.

Peritonitis is a disease caused by bacterial strains that have become increasingly resistant to many antibiotics. The development of alternative therapeutic compounds is the focus of extensive research, so novel nanoparticles (NPs) with activity against antibiotic-resistant bacteria should be developed. In this study, the antibacterial activity of quaternary ammonium polyethyleneimine (QA-PEI) NPs was evaluated against Streptococcus viridans, Stenotrophomonas maltophilia and Escherichia coli. To appraise the antibacterial activity, minimal inhibitory concentration (MIC), minimal bactericidal concentration and bactericidal assays were utilised with different concentrations (1.56-100 µg/ml) of QA-PEI NPs. Moreover, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and annexin V/propidium iodide toxicity assays were performed in cell cultures. MICs for S. maltophilia and E. coli isolates were 12.5 and 25 µg/ml, respectively, whereas the MIC for S. viridans was 100 µg/ml. Furthermore, the growth curve assays revealed that these QA-PEI NPs at a concentration of 12.5 µg/ml significantly inhibited bacterial growth for the bacterial isolates studied. On the other hand, QA-PEI NPs lacked significant toxicity for cells when used at concentrations up to 50 μg/ml for 48 h. The present findings reveal the potential therapeutic value of this QA-PEI NPs as alternative antibacterial agents for peritonitis, especially against Gram-negative bacteria.

PURIFICATION AND STRUCTURAL CHARACTERIZATION OF A PHTHALATE ANTIBIOTIC FROM BURKHOLDERIA GLADIOLI OR1 EFFECTIVE AGAINST MULTI-DRUG RESISTANT STAPHYLOCOCCUS AUREUS

A soil isolate, identified as Burkholderia gladioli OR1, has been reported in our earlier study, to possess broad spectrum antimicrobial activity against drug resistant clinical isolates of bacteria and fungi. The 16S rRNA gene sequence data of B. gladioli strain OR1 has been deposited in the GenBank databases (MTCC) under the accession number MTCC11251. Thin layer chromatography and bioautography studies of chloroform extract of the cell free supernatant of this organism, showed at least four different antimicrobial compounds. The silica gel column chromatography and high performance liquid chromatography led to the isolation of one compound that exhibited growth inhibitory activity against multi-antibiotic resistant clinical isolates of Staphylococcus aureus (resistant to amikacin, ciprofloxacin, clindamycin, clinafloxacin, erythromycin, gentamicin and methicillin). On the basis of mass, infra-red (IR), 1H nuclear magnetic resonance (NMR), 13C NMR and 2D NMR spectral studies, we propose the structure of this antibiotic to be bis-(2-ethylhexyl) phthalate, isolated for the first time from the species of the genus Burkholderia.

In vitro antimicrobial activity of fermented spices and <i>Capsicum Frutescens</i> against multi drug resistance clinical isolate and standard reference bacteria

Introduction : Food preservation is required to maintain for a long period of time. Traditional organic food preservative, “Datta” is spice mainly made up of Chili Peppers which frequently used in southern and western part of Ethiopia. can be consumed almost with every kind of foods and it is believed as appetizer and antimicrobial agent against food borne pathogen. This study aimed to assess in vitro antimicrobial activity of fermented condiment and Capsicum frutescens against multi drug resistance clinical isolate and standard reference bacteria. Method: samples collected from different level hotels and Capsicum frutescens (Chili peppers) were extractedin different solvents.Agar well diffusion assay was used to determine antimicrobial activity and minimum inhibitory concentration (MIC) and minimum bactericidal concentration was determined by tube dilution method. One way analysis of variant was used in comparison of the finding. Results: Extracted fermented condiment (Datta) sample and Chili Pepper showed antimicrobial activities against multidrug resistant clinical isolate and standard reference bacteria in well diffusion assay. extract showed MIC ranged from 25 mg/L to 66.7 mg/L and MBC ranged from 25 mg/L to 100 mg/L. The and Chili pepper extracts showed high antimicrobial activities against standard Staphylococcus aureus . The water based extract of sample were exhibited significantly low antimicrobial activities (P=0.000) as compared to the other extraction solvents. Conclusion: Water was weak extractor of active compounds having antimicrobial activities. Reference S. aureuswasmore susceptible organism while ATCC Salmonella enteritidis and clinical isolated multi-drug resistant E. coli less susceptible. The traditional use of fermented condiment for food preservation by the local people is supported by this study. Key words: Antimicrobial activity; Chili Pepper extract; Fermented condiment; Minimum bactericidal concentration; Minimum inhibition contraction Activite antimicrobienne en vitro d'epices fermentees et de fruits de capsicume pour la resistance aux medicaments isolate clinique et bacteries de reference standard Introduction: La conservation des aliments est necessaire pour maintenir pendant une longue periode de temps. Conservateur de nourriture organiqu et raditionnel, Datta est l'epice compose principalement de Chili Peppers qui frequemment utilize dans le sud et l'ouest de l'Ethiopie. peu tetre consomme presque avec toutes sortes d'aliments et on le croit comme un aperitif et un agent antimicrobien contre l'agent pathogene alimentaire. Cette etude visait a evaluer l'activite antimicrobienne in vitro du condiment fermente et Capsicum frutescens contre l'isolement clinique de resistance aux medicaments multiples et les bacteries de reference standard. Methode: Les echantillons de preleves dans des hotels de differents niveaux et Capsicum frutescens (Chili Peppers) ont ete extraits dans differents solvants. Un dosage de diffusion de puits a ete utilise pour determiner l'activite antimicrobienne et la concentration inhibitrice minimale (MIC) et la concentration bactericide minimale a ete determine par la methode de dilution du tube. Une analyse a sens unique de la variante a ete utilisee en comparaison de la decouverte. Resultats: L'echantillon extrait de condiments fermentes (Datta) et Chili Pepper ont montre des activites antimicrobiennes contre l'isolement Clinique resistant aux medicaments multiples et les bacteries de reference standard dans le dosage par diffusion de puits. L'extrait de a montreque le MIC variait de 25 mg / L a 66,7 mg / L et le MBC variait de 25 mg / L a 100 mg / L. Les extraits de poisson de et de Chili ont montre des activites antimicrobiennes elevees contre Staphylococcus aureus standard. L'extrait a base d'eau de l'echantillon de a montre des activites antimicrobiennes significativement faibles (P = 0,000) par rapport aux autres solvants d'extraction. Conclusion: L'eauetaitun extracteur faible de composes actifs ayant des activites antimicrobiennes. Reference S. aureus etait un organisme plus susceptible tandisque ATCC Salmonella enteritidis et E.coli . E. coli resistant aux medicaments multiples isoles etait moins susceptible. L'utilisation traditionnelle du condiment fermente pour la conservation des aliments par les populations locales est soutenue par cette etude. Mots cles: Activiteantimicrobienne; Extrait de poivre de piment; Condiment fermente; Concentration bactericide minimum; Contraction minimaled'inhibition

Ethnopharmacological uses of Sempervivum tectorum L. in southern Serbia: Scientific confirmation for the use against otitis linked bacteria

Ethnopharmacological relevanceSempervivum tectorum L. (Crassulaceae), known as houseleek, is used in traditional medicine in the treatment of ear inflammation. It can be spread as a pack on wounds, sores, burns, and abscesses and also on painful areas attacked by gout as a refrigerant and astringent. Drinking tea prepared from leaves of S. tectorum is recommended for ulcer treatment. The present study was designed to investigate ethopharmacological use of S. tectorum in the southern Serbia and to further scientifically justify and confirm effectiveness of the leaf juice used in ethnomedicine for ear inflammation, against otitis linked bacteria. Material and methodsEthnopharmacological survey on the use of S. tectorum in southern Serbia was performed using semi structured questionnaires via a face-to-face interview. Chemical composition of the leaf juice regarding phenolic compounds and organic acids was analyzed. Antimicrobial activity was tested on bacteria isolated from ear swabs of the patients suffering from the ear pain (otitis). Anti-quorum-sensing activities of the juice were further investigated on Pseudomonas aeruginosa. ResultsEthnopharmacological survey revealed the use of S. tectorum in southern Serbia for the treatment of ear pain, warts, cancer, stomachache, ulcer and high blood sugar level with the highest fidelity level (FL) for the ear pain. The phenolic composition of the S. tectorum leaf juice consisted of flavonol glycosides, with kaempferol-3-O-rhamnosyl-glucoside-7-O-rhamnoside as the majority compound. Organic acids composition revealed malic acid as the most dominant one. Antimicrobial and anti-quorum-sensing activities of the juice showed to be promising. ConclusionEthnopharmacological use of S. tectorum juice for treating ear pain is justified, since the juice possessed antimicrobial activity towards clinical isolates of bacteria linked to otitis.

Phytochemical and Antimicrobial Properties of Tamarix aphylla L. Leaves Growing Naturally in the Abha Region, Saudi Arabia

In this study, antimicrobial activities of some solvent extracts of fresh and dry leaves of Tamarix aphylla against eight clinical isolates of bacteria and Candida and the chemical compounds present in the hexane extract were determined. The results showed that cold-water extract has no antimicrobial effect against any of the microbes tested, while hot-water extract showed 75 % antimicrobial activities against the same microbes. Extracts involving methanol, chloroform, petroleum ether, acetone and diethyl ether of dry and fresh T. aphylla leaves showed a 100 % lethal effect against all the tested pathogenic microbes. Additionally, superior performance has been observed in the cases of methanol extract against Proteus mirabilis, chloroform and diethyl ether extracts against Klebsiella oxytoca, petroleum ether extract against Candida sp. compared with the standard antibiotic drug. The GC–MS analysis revealed that the leaves contain ten different chemical compounds; propenoic acid (28.99 %) and beta-d-mannofuranose (23.04 %) are found to be dominant. In conclusion, extraction methods using polar and nonpolar solvents of T. aphylla leaves showed great antimicrobial effect on pathogenic tested microbes. This could be used in the treatment of infectious diseases caused by multidrug-resistant bacterial strains “that are resistant to multidrug treatment” and Candida sp. From the pharmaceutical viewpoint, the identified phytochemical in the T. aphylla is reported to be biologically important and needs further investigation with regard to isolations to develop the safe and cheap drugs.

Multicenter study of antimicrobial susceptibility of anaerobic bacteria in Korea in 2012.

BackgroundPeriodic monitoring of regional or institutional resistance trends of clinically important anaerobic bacteria is recommended, because the resistance of anaerobic pathogens to antimicrobial drugs and inappropriate therapy are associated with poor clinical outcomes. There has been no multicenter study of clinical anaerobic isolates in Korea. We aimed to determine the antimicrobial resistance patterns of clinically important anaerobes at multiple centers in Korea.MethodsA total of 268 non-duplicated clinical isolates of anaerobic bacteria were collected from four large medical centers in Korea in 2012. Antimicrobial susceptibility was tested by the agar dilution method according to the CLSI guidelines. The following antimicrobials were tested: piperacillin, piperacillin-tazobactam, cefoxitin, cefotetan, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, metronidazole, and tigecycline.ResultsOrganisms of the Bacteroides fragilis group were highly susceptible to piperacillin-tazobactam, imipenem, and meropenem, as their resistance rates to these three antimicrobials were lower than 6%. For B. fragilis group isolates and anaerobic gram-positive cocci, the resistance rates to moxifloxacin were 12-25% and 11-13%, respectively. Among B. fragilis group organisms, the resistance rates to tigecycline were 16-17%. Two isolates of Finegoldia magna were non-susceptible to chloramphenicol (minimum inhibitory concentrations of 16-32 mg/L). Resistance patterns were different among the different hospitals.ConclusionsPiperacillin-tazobactam, cefoxitin, and carbapemems are highly active β-lactam agents against most of the anaerobes. The resistance rates to moxifloxacin and tigecycline are slightly higher than those in the previous study.

New Microbes New Infections promotes modern prokaryotic taxonomy: a new section "TaxonoGenomics: new genomes of microorganisms in humans".

“New Microbes and New Infections” being devoted to new facts in infections and clinical microbiology comprises a “New Genomes of Microorganisms and Viruses in Humans” section featuring its own format. This section will evolve towards a “TaxonoGenomics: new genomes of microorganisms in humans” section to better take into consideration recent developments in prokaryote genome sequencing and incorporate the recent proposal that genome sequence and proteome must be part of the description of microbes of medical interest. Indeed, there is an impressive rise in bacterial genome sequencing, with 35,000 genomes currently available from virtually all major bacterial phyla. These sequences are an unprecedented source of information to develop molecular assays for detection or genotyping, to detect antibiotic resistance and virulence markers, to develop new culture media or to identify candidate antigens for vaccines [1]. A second breakthrough was the use of MALDI-TOF-mass spectrometry (MALDI-TOF-MS) for the routine identification of clinical isolates of bacteria and fungi [2,3]. Finally, the renewal of culture, through the culturomics strategy based on a diversification of culture conditions, enabled identifying more than 120 new human-associated bacterial species in a limited time [4]. These three tools have in common the advantage of producing data that can easily be shared and compared, either in international databases or culture collections. Surprisingly, although it has undergone many changes over time according to the introduction of new diagnostic methods, microbial systematics has not been adapted to incorporate genomic sequence and MALDI-TOF-MS, despite the fact that these methods are now widely used worldwide. Currently, although there is no universal agreement on the rules and criteria used for microorganism identification, several taxonomic criteria, based on phenotypic and genotypic characteristics [5–7], are used to determine whether a new bacterium fulfils the requirements to be classified as a new taxon. These include: i) routinely obtainable phenotypic properties (morphology, staining and antigenic properties, growth preferences, enzyme production, sugar metabolism, susceptibility to antibiotics, pathogenesis and habitat) [8]; ii) chemotaxonomic parameters such as the characterization of polar lipids, whole cell fatty acid content, respiratory quinones and peptidoglycan structure [9–11]; and iii) the determination of DNA-DNA hybridization (DDH) [12]. However, the latter two taxonomic criteria lack inter- and intra-laboratory reproducibility, require the use of methods restricted to few laboratories, are of no practical value for the routine identification of bacterial isolates. Recently, several genomic tools have been proposed as alternatives of DDH for the taxonomic classification of prokaryotes, including average genomic identity of orthologous gene sequence (AGIOS), average nucleotide identity (ANI), digital DDH, maximum unique matches index (MUMi), multilocus sequence analysis, multilocus sequence typing, and tetranucleotide regression [13], the former three of which have permitted the valid publication of several new species names [14–24]. In addition, a new polyphasic taxonomic strategy named taxono-genomics including both MALDI-TOF-MS instead of chemotaxonomic analysis and genome sequence analysis, in addition to common phenotypic criteria, was proposed to describe eight new bacterial species [17–24]. Therefore, there is now clear evidence that genomic and MALDI-TOF-MS data may be integrated as alternatives to chemotaxonomy and DDH, respectively, for the taxonomic description of bacteria, provided that the new isolates are compared to the phylogenetically closest species with standing in nomenclature. Accordingly, “New Microbes and New Infections” will now accommodate two formats in the new “TaxonoGenomics” section, including a short 500-words format and one item to report on new genome of already described organism and a 1,500-word format and three items to report on new genome as part as the description of a novel organisms. This new section will accommodate only microbes of medical interest and not environmental ones without known connection with populations and patients.

Phenolic profile and antimicrobial activity of different dietary supplements based on Cochlospermum angolensis Welw.

Three different formulations (infusion, pills and syrup) of Cochlospermum angolensis were characterized by HPLC–DAD–ESI/MS regarding phenolic composition, and evaluated by their in vitro antimicrobial activity against clinical isolates of multiresistant bacteria. Infusion and pills showed the highest variety of phenolic compounds, with eleven molecules identified. Protocatechuic acid was only present in infusions, being the most abundant compound, while (epi) gallocatechin-O-gallate was the main molecule identified in pills and eucaglobulin/globulusin in syrup. Infusion revealed antimicrobial activity against all the studied bacteria with the exception of Proteus mirabilis whereas the pills revealed activity in Escherichia coli spectrum extended producer of β-lactamases and methicillin-resistant Staphylococcus aureus. In the syrup, there was no antimicrobial activity detected, which is in agreement with its low concentrations of phenolic compounds. None of the formulations inhibited P. mirabilis. Considering the obtained results, C. angolensis infusion can be considered a good source of phenolic compounds as well as a good antimicrobial agent.

Application of MALDI-TOF MS for identification of clinical isolates of bacteria from humans and animals

Routinely used diagnostic methods are insufficient to identify the microorganisms with unusual biochemical properties or less commonly occurring, including zoonotic microorganisms. During our study the possibility of identification of different bacteria isolated from humans and from breeding birds using MALDI-TOF MS (Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry) and biochemical methods was compared. The material for the study were 6 reference strains from ATCC, 30 isolates selected from healthy people (throat and nasal swabs) and 16 isolates selected from birds breeding (throat swabs from the vicinity of throat of asymptomatic birds and biopsies from the heart of the dead birds). Isolates were identified based on their biochemical properties (biochemical microtests and panels for biochemical analyzer Vitek 2) or based on a protein profile using MALDI-TOF MS technique. Biochemical methods were sufficient to identify the most common and relevant to human pathology pathogens such as e.g. Escherichia coli and Staphylococcus aureus; these results were consistent with the data obtained using MALDI-TOF MS. Identification of less common bacteria required the use of MALDI-TOF MS, because some bacteria isolated from humans or breeding birds could not be classified by their biochemical properties. The biggest differences were observed in the case of bacteria from the Pasteurellaceae family, which on the basis of biochemical properties were classified mainly as Haemophilus spp., whereas in accordance to the results obtained from the protein profile as Avibacterium endocarditidis. Identification of microorganisms using MALDI-TOF MS has proved to be more useful in the diagnosis of micro-organisms rarely isolated or problematic in routine diagnostics.

Incidence of carbapenem-resistant gram negatives in Italian transplant recipients: a nationwide surveillance study.

BackgroundBacterial infections remain a challenge to solid organ transplantation. Due to the alarming spread of carbapenem-resistant gram negative bacteria, these organisms have been frequently recognized as cause of severe infections in solid organ transplant recipients.Methods and FindingsBetween 15 May and 30 September 2012 we enrolled 887 solid organ transplant recipients in Italy with the aim to describe the epidemiology of gram negative bacteria spreading, to explore potential risk factors and to assess the effect of early isolation of gram negative bacteria on recipients’ mortality during the first 90 days after transplantation. During the study period 185 clinical isolates of gram negative bacteria were reported, for an incidence of 2.39 per 1000 recipient-days. Positive cultures for gram negative bacteria occurred early after transplantation (median time 26 days; incidence rate 4.33, 1.67 and 1.14 per 1,000 recipient-days in the first, second and third month after SOT, respectively). Forty-nine of these clinical isolates were due to carbapenem-resistant gram negative bacteria (26.5%; incidence 0.63 per 1000 recipient-days). Carbapenems resistance was particularly frequent among Klebsiella spp. isolates (49.1%). Recipients with longer hospital stay and those who received either heart or lung graft were at the highest risk of testing positive for any gram negative bacteria. Moreover recipients with longer hospital stay, lung recipients and those admitted to hospital for more than 48h before transplantation had the highest probability to have culture(s) positive for carbapenem-resistant gram negative bacteria. Forty-four organ recipients died (0.57 per 1000 recipient-days) during the study period. Recipients with at least one positive culture for carbapenem-resistant gram negative bacteria had a 10.23-fold higher mortality rate than those who did not.ConclusionThe isolation of gram-negative bacteria is most frequent among recipient with hospital stays >48 hours prior to transplant and in those receiving either heart or lung transplants. Carbapenem-resistant gram negative isolates are associated with significant mortality.

In vivo antibacterial activity and pharmacological properties of the membrane-active glycopeptide antibiotic YV11455

The membrane-active glycopeptide antibiotic YV11455 is a lipophilic cationic vancomycin analogue that demonstrates rapid and concentration-dependent killing of clinically relevant multidrug-resistant (MDR) Gram-positive bacteria in vitro. YV11455 was 2-fold and 54–270-fold more effective than vancomycin against clinical isolates of vancomycin-sensitive and vancomycin-resistant bacteria, respectively. In this study, the in vivo efficacy, pharmacodynamics, pharmacokinetics and acute toxicology of YV11455 were investigated. In vivo activity and pharmacodynamics were determined in the neutropenic mouse thigh infection model against meticillin-resistant Staphylococcus aureus (MRSA). YV11455 produced dose-dependent reductions in MRSA titres in thigh muscle. When administered intravenously, the 50% effective dose (ED50) for YV11455 against MRSA was found to be 3.3mg/kg body weight, and titres were reduced by up to ca. 3log10CFU/g from pre-treatment values at a dosage of 12mg/kg with single treatment. Single-dose pharmacokinetic studies demonstrated linear kinetics and a prolonged half-life, with an increase in drug exposure (area under the concentration–time curve) compared with vancomycin. The peak plasma concentration following an intravenous dose of 12mg/kg was 543.5μg/mL. Acute toxicology studies revealed that YV11455 did not cause any significant alterations in biochemical parameters or histological pictures related to major organs such as the liver and kidney at its pharmacodynamic endpoint (ED3-log kill). These findings collectively suggest that YV11455 could be used clinically for the treatment of infections caused by MDR Gram-positive bacteria.