Positive Microbes Research Articles

RF pulsed plasma modified composite scaffold for enhanced anti-microbial activity and accelerated wound healing

Infected wounds present significant challenges pertaining to healing and often demand administration of strong antibiotics to patients. Also, drug resistant microbes may alter the physiology of wounds to create biofilms, frequently leading to high morbidity and mortality. In this investigation, a biodegradable, microporous composite agarose-chitosan scaffold was fabricated. Furthermore, its surface was modified with diphenyldiselenide deposition, using low pressure pulsed plasma technology. The optimized plasma parameters, viz. 5ON/15OFF (ms) of plasma pulse rate and 80 min of treatment time resulted in scaffolds having enhanced anti-bacterial activity against gram positive microbes like Staphylococcus (S.) aureus and S. epidermidis. The scaffolds were non-toxic to skin cells, as confirmed by the MTT assay. Cell proliferation through plasma treated and native scaffolds was assessed by culturing primary human dermal fibroblasts (HdaF) and human keratinocytes (HaCaT) and visualizing via confocal microscopy. Moreover, in-vivo rat model confirmed accelerated wound healing with plasma treated scaffold (100 % on day 14), as compared to the native scaffold (100 % on day 16) when compared with over-the-counter (OTC) ointment Betadine (100 % on day 12).

Formulation and Evaluation of Herbal Hand Sanitizer

Hands are the to begin with mode of transmission of organisms and diseases. Hand cleanliness is a key guideline and work out in the anticipation, control and lessening of contaminations. Due to COVID widespread the require of hand sanitizer has expanded which causes less dryness to hand. Considering the require, we arranged a polyherbal sanitizer utilizing seven plant extricates with other fixings counting isopropyl liquor, camphor, hydrogen peroxide, glycerol and water. The fixings were chosen on the premise of their antimicrobial property. The fixings and sanitizer were assessed for antimicrobial property and appeared strong action against gram positive microbes S. aureus, though blend of extricates appeared strong action against all the bacterial strains utilized but B. cereus. The sanitizer moreover appeared strong action against all the strains utilized in the climbing arrange of Klebsiella spp. > B. cereus > S. aureus > S. pyogenes > P. aeruginosa > Dermatophyte > E. coli and gave zone of hindrance of 18±0.05, 12±0.03, 11±0.01, 10±0.01, 9±0.5, 9±0.01 and 7±0.001 mm separately. The antimicrobial action was compared with other commercial hand sanitizer and greatest movement was appeared against Klebsiella spp. and least against E. coli and P. aeruginosa by all the sanitizer utilized. The adequacy of hand sanitizer was checked on hands of 38 volunteers of research facility specialists, patients and their relatives with composed and verbal assent. The sanitizer decreased or disposed of the development of pathogens confined from hands. Time interim impact was moreover checked at a time crevice of two hours too appeared the impact of hand sanitizer for longer time with diminishment in bacterial development. The sanitizer pH was soluble with great rack, surface and odor. No turbidity was seen when kept at higher temperature for 3 months and appeared no skin dryness with relieving impact after utilizing sanitizer on diverse volunteers.

Urine biomarkers individually and as a consensus model show high sensitivity and specificity for detecting UTIs

BackgroundCurrent diagnoses of urinary tract infection (UTI) by standard urine culture (SUC) has significant limitations in sensitivity, especially for fastidious organisms, and the ability to identify organisms in polymicrobial infections. The significant rate of both SUC “negative” or “mixed flora/contamination” results in UTI cases and the high prevalence of asymptomatic bacteriuria indicate the need for an accurate diagnostic test to help identify true UTI cases. This study aimed to determine if infection-associated urinary biomarkers can differentiate definitive UTI cases from non-UTI controls.MethodsMidstream clean-catch voided urine samples were collected from asymptomatic volunteers and symptomatic subjects ≥ 60 years old diagnosed with a UTI in a urology specialty setting. Microbial identification and density were assessed using a multiplex PCR/pooled antibiotic susceptibility test (M-PCR/P-AST) and SUC. Three biomarkers [neutrophil gelatinase-associated lipocalin (NGAL), and Interleukins 8 and 1β (IL-8, and IL-1β)] were also measured via enzyme-linked immunosorbent assay (ELISA). Definitive UTI cases were defined as symptomatic subjects with a UTI diagnosis and positive microorganism detection by SUC and M-PCR, while definitive non-UTI cases were defined as asymptomatic volunteers.ResultsWe observed a strong positive correlation (R2 > 0.90; p < 0.0001) between microbial density and the biomarkers NGAL, IL-8, and IL-1β for symptomatic subjects. Biomarker consensus criteria of two or more positive biomarkers had sensitivity 84.0%, specificity 91.2%, positive predictive value 93.7%, negative predictive value 78.8%, accuracy 86.9%, positive likelihood ratio of 9.58, and negative likelihood ratio of 0.17 in differentiating definitive UTI from non-UTI cases, regardless of non-zero microbial density. NGAL, IL-8, and IL-1β showed a significant elevation in symptomatic cases with positive microbe identification compared to asymptomatic cases with or without microbe identification. Biomarker consensus exhibited high accuracy in distinguishing UTI from non-UTI cases.ConclusionWe demonstrated that positive infection-associated urinary biomarkers NGAL, IL-8, and IL-1β, in symptomatic subjects with positive SUC and/or M-PCR results was associated with definitive UTI cases. A consensus criterion with ≥ 2 of the biomarkers meeting the positivity thresholds showed a good balance of sensitivity (84.0%), specificity (91.2%), and accuracy (86.9%). Therefore, this biomarker consensus is an excellent supportive diagnostic tool for resolving the presence of active UTI, particularly if SUC and M-PCR results disagree.

Synthesis and computational studies of potent antimicrobial and anticancer indolone scaffolds with spiro cyclopropyl moiety as a novel design element

The indolones nucleus is the central core to develop new effective anticancer agents and its substitution at the 3-position can affect antitumor activity, 3-spirocyclopropyl-2-oxindoles have attracted the scientist's community to design and develop expedition's strategies towards their construction and explore the potential of this useful scaffold with their newer derivatives in medicinal world. The present paper describes the synthesis of 3-spirocyclopropyl-2-indolone derivatives in three steps via synthesis of ylide leading to methylene-indolinones followed by the formation of the final product spirocyclopropyl oxindole derivatives with improved yields. In this milieu we considered motivating to advance exploration the biological potencies and computational studies of our newly synthesized molecules. The aimed target molecules were screened for antimicrobial and anticancer activities where they exhibited substantial effective antimicrobial activities. Amongst them, potent compound, bromospirocyclopropyl indolone, 6d displayed encouraging MIC ranging from 0.007 to 0.49 μg/mL for gram positive microbes and also substantial anticancer activity with an IC50 of 11.5 μg/mL. Finally, the computational modelling studies were performed to explore structure-activity relationship analysis. Active site of receptor protein shows docking scores of these molecules as - 5.78 kcal/mol and −5.097 kcal/mol for the docked target proteins. The binding energy of the best score is found to be −41.67 kcal/mol to −44.67 kcal/mol. Thus, the present paper efficaciously validated spirocyclopropyl indolone framework for drug candidates as potent anticancer as well as antimicrobial compounds.

Antibacterial Activity of Sea Buckthorn (Hippophae rhamnoides L.) against Pathogenic Microbes

Sea buckthorn (Hippophae rhamnoides L.) is a unique and valuable plant and has recently gained worldwide attention mainly for its medicinal and nutritional potential. It is a thorny bush with yellow-orange pearl shaped fruits and has a high content of vitamins, minerals, natural antioxidants and omega-3,6 fatty acids.Doses of 2 mg/ml, 4 mg/ml and 6 mg/mlof aqueous extract of plant berry powder were evaluated against Gram positive and Gram negative microbes by usingdisc diffusion and agar well diffusion method. The zone of inhibition was compared with the standard drugs vancomycin andKanamycin(30 µg/ml). It was concluded that the aqueous extract of berry powder has antibacterial activity, which may be used to preventvarious diseases and can be incorporated in human and animal diet.

Green Synthesis of Rod Shaped ZnO using Extract of Origanum majorana Leaf and Investigation for Antibacterial Applications

In this research article, we have fabricated the zinc oxide (ZnO) nanoparticles (NPs) with help of aqueous extract of leaf of Origanum majorana and studied their antimicrobial activity. Origanum majorana is one of medicinally important plant of Lamiaceae/Labiatae family. Green-approach of NPs has been favoured over traditional synthesis methods, as plant-based extracts have phytochemicals, which are non-toxic and biologically safe. The phytochemicals such as flavonoids, derivatives of phenol and polyphenolic biomolecules are found to be in aqueous leaf extract of Origanum majorana which used as capping and reducing agents. They include many functional groups such as-OH, -C=O and more which improve the physicochemical properties of NPs and consequently affect their targeting towards specific molecules. Plant mediated synthesis of ZnO NPs with fresh leave extract of Origanun majorana is also simple, quick and provides a vast array of functionalised NPs of particular size and morphology. Herein, ZnO NPs have been prepared with 3 mL of 25% (w/v) of leaf extract of Origanum majorana (Maruva). These synthesized NPs have been characterized using PXRD (Powder X-ray diffraction), FT-IR (Fourier transform-infra-red spectroscopy), UV-Visible spectroscopy, SEM (Scanning electron microscopy) with EDS (Energy dispersive spectroscopy). UV-Visible spectrum shows maximum absorbance at 379.75 nm and energy band gap have been evaluated 2.84 eV using tauc plot. Obtained PXRD pattern shows hexagonal wurtzite crystalline structure which is similar as reported in the literature (JCPDS No-36-1451). The morphology of synthesized NPs has been obtained with SEM images. These NPs are rod shaped with width calculated approximately 90 nm-125 nm and length 0.5μm-1.2μm respectively. The EDS analysis shows the 51.41% of zinc (Zn) and 48.49% of oxygen (O)elemental composition of fabricated nanoparticles. Antimicrobial activity has been performed on gram negative and gram positive microbes with the help of broth dilution method. These synthesized NPs shows very great bactericidal activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Streptococcus pneumoniae respectively. Minimum inhibitory concentrations (MIC) have been investigated 175μg/mL for Pseudomonas aeruginosa, 125 μg/mL for Escherichia coli and 100 μg/mL for both the Staphylococcus aureus and Streptococcus pneumoniae respectively.

Green synthesis of gold nanoparticles using Kaempferia parviflora rhizome extract and their characterization and application as an antimicrobial, antioxidant and catalytic degradation agent

BackgroundPlant based synthesis of nanoparticles is a green chemistry approach which links plants with nanotechnology and look to be the best substitute against synthetic nano-products. Gold nanoparticles (AuNPs) mediated plant extracts are providing huge biological and environmental applications including antioxidant, anti-inflammatory, antimicrobial anticancer activities and catalytic action. Kaempferia parviflora (K. parviflora) is a medicinal plant commonly known as black ginger (BG), which has extensive pharmacological activities. EcofriendlyAuNPs was synthesized using an aqueous extract of K. parviflora rhizome. The synthesized black ginger gold nanoparticles (BG-AuNPs) was stabilized by chloroauric acid (0.1 mM) and the reaction was completed by 30 min at 30°C. The BG-AuNPs were characterized by UV-vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM).Significant findings The TEM analysis confirmed the BG-AuNPs were well dispersed and smooth surfaced spherical structure with high crystal in nature. The BG-AuNPs showed an excellent antimicrobial activity against both Gram negative and Gram positive microbes and also provided the high antioxidant ability. The BG-AuNPs is a potent catalyst in the MO degradation using sodium borohydride.

Tetracycline Water Soluble Formulations with Enhanced Antimicrobial Activity.

The negligible water solubility of tetracycline (TC), a well-known antibiotic of clinical use, is the major disadvantage for its oral administration. With the aim to improve the water solubility of TC, the micelles of formulae SLS@TC and CTAB@TC (SLS = sodium lauryl sulphate and CTAB = cetrimonium bromide) were synthesized. The micelles SLS@TC and CTAB@TC were characterized by melting point (m.p.), thermogravimetric differential thermal analysis (TG-DTA), differential scanning calorimetry (DTG/DSC), attenuated total reflection spectroscopy (FT-IR-ATR), ultra-violet visible (UV/vis) spectroscopy, proton nucleus magnetic resonance (1H-NMR) spectroscopy, and the ultrasonically-induced biregringence technique. The antimicrobial activity of SLS@TC and CTAB@TC was evaluated, by means of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and inhibition zone (IZ), against the Gram negative bacterial strains Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli) and the Gram positive ones of the genus of Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus). Generally, both micelles show better activity than that of TC against the microbial strains tested. Thus, the MIC value of CTAB@TC is 550-fold higher than that of free TC against S. epidermidis. Despite the stronger activity of CTAB@TC than SLS@TC against both Gram negative and Gram positive microbes, SLS@TC is classified as a bactericidal agent (in that it eliminates 99.9% of the microbes), in contrast to CTAB@TC, which is bacteriostatic one (inhibits, but does not kill the organisms). The toxicity of SLS@TC and CTAB@TC was evaluated against human corneal eukaryotic cells (HCECs). Moreover, SLS@TC and CTAB@TC exhibit low in vivo toxicity against Artemia salina, even at concentrations up to threefold higher than those of their MICmax. Therefore, SLS@TC and CTAB@TC can be candidates for the development of new antibiotics.

Microbiological analyses of nasally guided catheters after less invasive surfactant administration \u2013 a pilot study

BackgroundRespiratory distress syndrome (RDS) is a frequent complication of premature birth. Treating RDS by continuous positive airway pressure and less invasive surfactant administration (LISA) may reduce bronchopulmonary dysplasia. Surfactant, however, can be inactivated by bacterial infection. Therefore, potential routes of microbe transmission into the airway are of interest. The aim of this study was to evaluate microbiological contamination of catheters used for LISA procedures and its association with postnatal age.MethodsCatheter tips used for LISA procedures via the nasal route (LISA-n) in infants with RDS were placed into a sterile eSwab container directly after the procedure, cultured and examined for microbiological contamination.ResultsInterpretable results could be collected from 20 catheter tips. Four showed positive culture results (20%) with microbes potentially associated with the development of early onset neonatal sepsis. Risk of positive microbe detection increased with postnatal age (< 4 h: 10%; 4–18 h: 20%; > 18 h: 40%).ConclusionsIn this pilot study, the risk of tracheal microbe transmission following the LISA-n procedure increased with postnatal age. Although the clinical relevance of this finding is unclear, earlier surfactant administration might reduce the risk of catheter contamination.Trial registration numberSubstudy of the registered Trial: feasibility study – Neofact: NCT04086095, www.ClinicalTrials.gov, September 11, 2019.

TLC-bioautography identification and GC-MS analysis of antimicrobial and antioxidant active compounds in Musa × paradisiaca L. fruit pulp essential oil.

The absence of microbial growth and resistance to oxidative deterioration in fruits of Musa × paradisiaca L. (bananas) is an indication of the presence of antimicrobial and antioxidant metabolites. In order to investigate the secondary metabolomic spectrum as well as the active antimicrobial and antioxidants present in essential oils (EOs) from fruits of different geographical areas of M. × paradisiaca, gas chromatography-mass spectroscopy (GC-MS) principal component data correlation analysis is complemented with antimicrobial assays and phytochemical and bioautographic antioxidant fingerprints with thin layer chromatography (TLC). An EO was obtained by steam distillation and subjected to GC-MS and TLC for metabolomic profiling from fruit pulp. The antimicrobial potential was tested in both Escherichia coli as a gram negative and Bacillus subtilis as a gram positive microbe. Potential antioxidant metabolites were identified through TLC-bioautography and GC-MS analysis of active zones. A maximum of 0.56% v/w EO was isolated from fruit pulps of M. × paradisiaca. Minimum inhibitory concentrations (MICs) against B. subtillis and E. coli were 0.25 and 0.35μg/mL, respectively. Thus, 56 metabolites were identified through GC-MS. The major abundant antimicrobial metabolites found in EOs are α-thujene, γ-terpinene, α- and β-pinene, sabinene, β-myrcene, limonene, α-capaene, caryophyllene and (Z,E)-α farnesene. Aceteugenol, palmitic acid, stearic acid, palmitin, and stearin were identified as antioxidant metabolites. Principal component analysis of metabolite data reveals correlations and a clear separation based on metabolites obtained from various areas. The data generated using metabolic profiling and cluster analysis helped to identify antimicrobial and antioxidant compounds in M. × paradisiaca.

Bacterial agents and their antibiotic susceptibility in neonatal sepsis in high dependency NICU of Tertiary Care Hospital

Background: The type of bacterial flora causing neonatal sepsis varies in different parts of world and the emerging of resistance to various antibiotics has been a challenge currently faced by microbiologists and neonatologist’s worldwide. The aim of this study was to isolate the bacteriological agent causing the neonatal sepsis and determination of their susceptibility to antibiotics. Methods: In this study, neonates suspected of sepsis who were admitted to Neonatal Intensive Care Unit (NICU) were assessed. Neonates with positive blood culture and with clinical signs of sepsis were enrolled in the study. The other parameters included: age, sex, birth weight, gestation, type of infection, type of isolated pathogen along with their antibiotic sensitivity and the outcome of disease. Results: 1440 neonates with suspected sepsis were included in study, out of 1440 patients, blood cultures were taken from all patients, 180cultures (12.5%) were reported as positive. in 32 cultures (17.7%) gram positive microbes were isolated while in 148 cultures (82.2%) gram negative microorganisms were detected.The mostcommon microorganisms isolated were; Klebsiella pneumonia (33.05%), Acintobacter Spp. (17.01%), Pseudomonas (13.26%), Escherishia-coli (8.75%),Coagulase negative staphylococci (CONS) (11.94%), MRSA (6.59%), Enterobacter (4.44%), Citrobacter (4.37%) and Enterococcus(2.36%). All of the klebsiella and enterobacter strains were resistant to ampicillin and gentamicin. Acintobacter Spp., and Citrobacter, were multidrug resistant with their sensitivity to imipenem was 40 to 45 % while for tigicycline was near 90%.The sensitivity of K. pneumonia and enterobacter to imipenem was: 90 and 94%, respectively.61.66% of our patients were preterm, early and late-onset sepsis was seen in 71 and 29% of patients respectively. Mortality rate was high 61.76% among preterm patients with sepsis while as overall mortality rate was 37.77%. Conclusion: In this study we found most common cause of bacterial sepsis was K. pneumoniae which was completely resistant to ampicillin and gentamicin. It therefore re-emphasis the need to change the empirical treatment of sepsis with ampicillin and gentamicin.

Magnetically Separable Fe3 O4 @CdS Type-II Nanohybrids with Excellent Photocatalytic Activity and Antibacterial Properties.

A magnetically separable Fe3 O4 @CdS type-II core-shell nanohybrid (NH) photocatalyst, with excellent antibacterial properties and photocatalytic activity, was synthesized and characterized by means of structural, elemental, and morphological analyses. Steady-state and time-resolved emission and absorption spectroscopy were also exploited to realize the location of charge-carrier wave functions in the NHs. The antibacterial activity of NHs was then evaluated against Escherichia coli (1.4×108 CFU mL-1 ; CFU=colony forming units) and Staphylococcus saprophyticus (1.2×108 CFU mL-1 ) as model strains of Gram-negative and -positive microbes. Compared with CdS and Fe3 O4 , the as-synthesized Fe3 O4 @CdS composite exhibited highly improved bactericidal activity and recyclability. Concentration values of 5.0 and 4.0 mg mL-1 were required for Fe3 O4 @CdS NHs to inhibit the growth of E. coli and S. saprophyticus, respectively. The contribution of OH. radicals to photocatalysis at the Fe3 O4 @CdS surface was also considered. Moreover, thiobarbituric acid reactive substances and protein carbonyl assay protocols have been exploited to monitor levels of oxidative damage to lipids and proteins in cells. Additionally, the photocatalytic activity of Fe3 O4 @CdS NHs was monitored for the degradation of xylenol orange dye. Compared with CdS and Fe3 O4 , as-synthesized Fe3 O4 @CdS displayed superior performances in the photodegradation of xylenol orange. Possible mechanisms involved in the degradation of xylenol orange are also discussed.

Incidence and Risk Factors of Perioperative Mortality in Pediatric ICU Patients.

BackgroundThere is a limited data of pediatric patients who presented to the intensive care unit (ICU) and undergo procedures under general anesthesia. The primary objective of this study was to evaluate the mortality of this population and assess the risk factors associated with mortality.MethodsRetrospective study of electronic medical records of pediatric patients who admitted to medical/surgical ICU and underwent produces under general anesthesia during the same ICU admission was performed. Incidence of mortality was obtained and risk factors associated with these mortalities were examined using Univariable logistic regression analysis.ResultsThe mortality of pediatric patients who were admitted to the ICU and underwent procedures under general anesthesia was 12.6%, while the mortalities of patients without procedures under general anesthesia and patients who admitted to ICU for postoperative management were 3.5% and 0.4%, respectively. Higher ASA class, emergency cases, higher ventilator support, more inotrope requirement, positive microbe in blood stream, blood transfusion requirement, and general surgery or hematological procedures were highly associated with mortalities. Among them, positive blood stream infection was highest odds ratio (102.00, 95% confidence interval 9.78–1064.09). The profile of patients with positive blood stream infection showed that most of them had underlying immunological/hematological disorders.ConclusionIn our institution, pediatric patients who admitted to the ICU and underwent procedures under general anesthesia demonstrated the highest mortality among other patients who admitted to ICU. Risk factor analysis demonstrated that patients with positive blood stream infection had highest odds ratio, and were highly associated with immunological/ hematological disorders.

Antimicrobial Activity of Coleus Ambonicus Herbal Finish on Cotton Fabric

An extract obtained from Coleus Ambonicus was applied on cotton fabric by means of the exhaust, micro encapsulation and nano encapsulation methods, and the antimicrobial activity of the finished fabric assessed quantitatively by the AATCC test method 100 against gram positive (staphylococcus aureus) and gram negative (Escherichia coli) microbes. The finish applied on the the samples using all three methods exhibit a good bacterial reduction percentage. The finish applied on the samples using all three methods possesses a higher bacterial reduction percentage against gram positive microbes than gram negative, even after washing. The method of washing conforms to ISO method 3. The wash durability of the antimicrobial activity was assessed by the bacterial reduction percentage after washing. The wash durability of the samples using the direct exhaust method was very poor and it lost its antimicrobial activity after 10 wash cycles. The wash durability of the samples using the micro encapsulated method shows antimicrobial activity up to 10 wash cycles, dropping gradually to very low levels at 20 wash cycles. The wash durability of the samples using nano encapsulation shows good antimicrobial activity against both gram positive and gram negative microbes even after 30 washes

Enhanced Virgin Coconut Oil (EVCO) as Natural Postmilking Teat Germicide to Control Environmental Mastitis Pathogens

The antimicrobial capability of oil containing medium-chain fatty acids and their corresponding monoglycerides, known as Enhanced Virgin Coconut Oil (EVCO) against microorganisms isolated from bovine mastitis milk was studied. EVCO contains an effective amount of medium-chain free fatty acids (caprylic, capric and lauric acid) and their corresponding derivatives (monocaprylin, monocaprin and monolaurin) can act as antimicrobial agent with broad spectrum of antimicrobial properties. An in vitro assessment of EVCO against bovine mastitis microorganisms isolated from locally collected mastitis milk samples was conducted to determine its minimum bactericidal concentration (MBC >99 ). In general, EVCO exhibited its great antimicrobial capability to kill all mastitis microorganisms isolated from the mastitis milk sample at different concentrations of MBC >99 value. In fact, EVCO was found more effective to kill Mycoplasma sp. and gram positive microbes rather than gram negative microbes, especially in Mycoplasma bovis, Acholeplasma oculi , Enterococcus sp. , Streptococcus sp. and Staphylococcus aureus with lower MBC >99 values in comparison with the synthetic antibiotic, Mastivet. A further investigation of the antimicrobial activities of EVCO against Staphylococcus aureus and Mycoplasma bovis against time revealed that EVCO was more efficient in killing these two microorganisms in a shorter time at a lower concentration as opposed to Mastivet. These findings indicated that EVCO has great potential application in postmilking teat germicide, which can be used as a preventive measure to control mastitis cases, especially against environmental mastitis pathogens.

Bio Fabrication of Silver Nanoparticle from Argemone mexicana for the Control of Aedes albopictus and their Antimicrobial Activity.

Plant synthesized silver nanoparticles give rapid control on mosquito larvae of dengue vector, Aedes albopictus. AgNPs synthesized from the plant, Argemone mexicana for the control of larvae and these nanoparticles inhibit the growth of microbes are broad spectrum of nanoparticle activities. Nanoparticles were subjected to analysis by UV-vis spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. Furthermore, laboratory evaluation of plant mediated nano-particle carried out lethal toxicity on Aedes albopictus. The characterization studies confirmed the spherical shape and size (5-50 nm) of silver nano-particles. The efficacy of AgNPs was tested at concentration of 2 to 10 ppm against L1 to L4 larval instar of A. albopictus. The LC50 followed by LC90 values were (L1) 5.24, 8.66; (L2) 5.56, 8.85; (L3) 6.20, 10.01 and (L4) 7.04, 10.92 at 10 ppm of silver nanoparticle, whereas LC50 (LC90) values of (L1) 7.63, 11.58; (L2) 8.17, 11.88; 8.80, 12.82 and 8.94, 12.26 at 10 ppm of plant extract alone treated larvae, respectively. The mortality rates were positively correlated with the concentration of AgNPs. Significant (P<0.05) high square value changes in the larval mortality were also recorded between the period of exposure against all larval instar of A. albopictus. Silver nanoparticles were also tested for antimicrobial activity and significant toxicity inhibition was observed against the gram positive microbes and it exhibited mild toxicity against P. aeroginosa. Plant, A. mexicana synthesized silver nano-particles are rapid and potential mosquito larvicidal as well as antimicrobial agents. Finding of our results support that silver nanoparticles can be prepared in a simple and cost-effective manner and are suitable for bio-formulation against mosquitoes and microbes.

POLA KUMAN AEROB DAN KEPEKAAN ANTIMIKROBA PADA ULKUS KAKI DIABETIK

Diabetic foot ulcer is a common complication of diabetic disease which causes morbidity and foot amputation. One major pathogenesis is infection. Microbes which infect are varied. The use of inappropriate antimicrobials can or may cause drugs resistance. Data of microbes pattern and sensitivity test is important and may guide the clinician in giving the initial therapy. The aim of this retrospective study was to know the characteristics, microbial pattern, and the sensitivity to antimicrobial drugs of 31 diabetic foot ulcer patients who were hospitalized at Wahidin Sudirohusodo Hospital, Makassar in the period of January 2009 until June 2010. The study results showed the age mean was 54.06±12.4 years old, and the onset of diabetes mellitus was 7.62±5.77 years. The common microbes were gram negative bacteria (73.52%) including Enterobacter agglomerans, Proteus mirabilis and Klebsiella pneumonia, while the most common gram positive microbe was Streptococcus sp. Gram positive microbes were sensitive to meropenem, ceforoxim and amoxilin, while Gram negative microbes were sensitive to meropenem. Based on this study, the researchers concluded that the most common microbes which infect the feet were gram negative microbes. Gram positive microbes were still sensitive to meropenem, ceforoxim and amoxilin. Gram negative microbes were sensitive to meropenem.

A lack of synergy between membrane-permeabilizing cationic antimicrobial peptides and conventional antibiotics

The rapid rise in morbidity and mortality from drug-resistant pathogenic bacteria has generated elevated interest in combination therapy using antimicrobial agents. Antimicrobial peptides (AMPs) are a candidate drug class to advance the development of combination therapies. Although the literature is ambiguous, the generic membrane disrupting activity of AMPs could enable them to synergize with conventional small molecule antibiotics by increasing access to the cell and by triggering membrane damage mediators. We used a novel assay to measure interactions, expressed as fractional inhibitory concentration (FIC), between four conventional antibiotics in combination with four well-characterized, membrane permeabilizing AMPs, against three species of Gram negative and Gram positive bacteria, giving 40 total pair-wise measurements of FIC with statistical uncertainties. We chose a set of AMPs that are known to dramatically disrupt the membranes of both Gram negative and Gram positive bacteria. Yet none of the membrane permeabilizing antimicrobial peptides interacted synergistically with any of the conventional antibiotic drugs in any organism. Large-scale membrane disruption and permeabilization by AMPs is not sufficient to drive them to act synergistically with chemical antibiotics in either Gram negative or Gram positive microbes.

Evaluation of the bactericidal activity of galectins.

Over a century ago, Karl Landsteiner discovered that blood group antigens could predict the immunological outcome of red blood cell transfusion. While the discovery of ABO(H) blood group antigens revolutionized transfusion medicine, many questions remain regarding the development and regulation of naturally occurring anti-blood group antibody formation. Early studies suggested that blood group antibodies develop following stimulation by bacteria that express blood group antigens. While this may explain the development of anti-blood group antibodies in blood group negative individuals, how blood group positive individuals, who cannot generate anti-blood group antibodies, protect themselves against blood group positive microbes remained unknown. Recent studies suggest that several members of the galectin family specifically target blood group positive microbes, thereby providing innate immune protection against blood group antigen positive microbes regardless of the blood group status of an individual. Importantly, subsequent studies suggest that this unique form of immunity may not be limited to blood group expressing microbes, but may reflect a more generalized form of innate immunity against molecular mimicry. As this form of antimicrobial activity represents a unique and unprecedented form of immunity, we will examine important considerations and methodological approaches that can be used when seeking to ascertain the potential antimicrobial activity of various members of the galectin family.

High-Throughput Discovery of Peptide Antibiotics: A Delicate Balance Between Antimicrobial Potency, Solubility and Target Selectivity

Antimicrobial peptides (AMPs) are key components of the innate immune systems of many organisms. AMPs function by permeabilizing microbial membranes, giving them an important advantage over conventional antibiotics as they may elude the selection of drug-resistance. Therefore, there has been increasing interest in engineering AMPs and improving their bioactivity over the last three decades. Yet the lack of obvious structure-function relationships or molecular design principles has obstructed the development of new AMPs. To circumvent this roadblock, we are developing a high-throughput approach to select AMPs that are optimized in all of the critical factors simultaneously. Previously in our lab, we identified a group of broad-spectrum antimicrobial peptides from a synthetic peptide library. Here, we used one of the broad-spectrum AMPs, ∗ARVA (RRGWALRLVLAY), to study the potency, selectivity and mechanism of action of AMPs in the presence of concentrated human erythrocytes (10⊥9 cells/ml) which mimics the in vivo milieu. ∗ARVA, and other AMPs, lose antimicrobial activity in concentrated erythrocytes. We developed a method to make direct measurements of peptide binding to cells which showed that loss of activity is due to weak host cell binding, coupled with the large mass excess of host cell vs. bacterial cells under physiological conditions. To identify AMPs with clinically-relevant activity, we are developing a novel, orthogonal high-throughput screen in which we select simultaneously for 1) peptide solubility; 2) lack of host cell lysis; 3) sterilization of a Gram positive microbe in the presence of concentrated erythrocytes, and 4) sterilization of a Gram negative microbe in the presence of concentrated erythrocytes. Our results show that rational library design and high-throughput screening is a promising approach to identify AMPs that have the needed balance between antimicrobial potency, solubility and target cell selectivity.