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Fulltext Clinical and bacteriological profile of diabetic foot infections in a tertiary care

Goh TC, Bajuri MY, C Nadarajah S, Abdul Rashid AH, Baharuddin S, Zamri KS

J Foot Ankle Res, 2020 Jun 16;13(1):36.
PMID: 32546270 DOI: 10.1186/s13047-020-00406-y

BACKGROUND: Diabetic foot infection is a worldwide health problem is commonly encountered in daily practice. This study was conducted to identify the microbiological profile and antibiotic sensitivity patterns of causative agents identified from diabetic foot infections (DFIs). In addition, the assessment included probable risk factors contributing to infection of ulcers that harbour multidrug-resistant organisms (MDROs) and their outcomes.
METHODS: We carried out a prospective analysis based on the DFI samples collected from 2016 till 2018. Specimens were cultured with optimal techniques in addition to antibiotic susceptibility based on recommendations from The Clinical and Laboratory Standards Institute (CLSI). A total of 1040 pathogens were isolated with an average of 1.9 pathogens per lesion in 550 patients who were identified with having DFIs during this interval.
RESULTS: A higher percentage of Gram-negative pathogens (54%) were identified as compared with Gram-positive pathogens (33%) or anaerobes (12%). A total of 85% of the patients were found to have polymicrobial infections. Pseudomonas aeruginosa (19%), Staphylococcus aureus (11%) and Bacteroides species (8%) appeared to be the predominant organisms isolated. In the management of Gram-positive bacteria, the most efficacious treatment was seen with the use of Vancomycin, while Imipenem and Amikacin proved to be effective in the treatment of Gram-negative bacteria.
CONCLUSION: DFI's are common among Malaysians with diabetes, with a majority of cases displaying polymicrobial aetiology with multi-drug resistant isolates. The data obtained from this study will be valuable in aiding future empirical treatment guidelines in the treatment of DFIs. This study investigated the microbiology of DFIs and their resistance to antibiotics in patients with DFIs that were managed at a Tertiary Care Centre in Malaysia.

Matched MeSH terms: Gram-Negative Bacteria/classification*; Gram-Negative Bacteria/drug effects; Gram-Negative Bacteria/isolation & purification
Fulltext An efficient approach for the synthesis of novel methyl sulfones in acetic acid medium and evaluation of antimicrobial activity

Ravi Kumar G, Dasireddy CR, Varala R, Kotra V, Bollikolla HB

Turk J Chem, 2020;44(5):1386-1394.
PMID: 33488238 DOI: 10.3906/kim-2003-10

A series of nine methyl sulphones ( 3a -3 i ) starting from the aldehydes ( 1a-1i ) were synthesized in two consecutive steps. In the first step, preparation of allyl alcohols ( 2a-2i ) from their corresponding aldehydes by the reaction of sodium borohydride in methanol at room temperature is reported. Finally, methyl sulphones are synthesized by condensing sodium methyl sulfinates with allyl alcohols in the presence of BF 3 .Et 2 O in acetic acid medium at room temperature for about 2-3 h. The reaction conditions are simple, yields are high (85%-95%), and the products were obtained with good purity. All the synthesized compounds were characterized by their 1 H, 13 C NMR, and mass spectral analysis. All the title compounds were screened for antimicrobial activity. Among the compounds tested, the compound 3f has inhibited both Gram positive and Gram negative bacteria effectively and compound 3i has shown potent antifungal activity. These promising components may help to develop more potent drugs in the near future for the treatment of bacterial and fungal infections.

Matched MeSH terms: Gram-Negative Bacteria
Detection of mobile colistin-resistance gene variants (mcr-1 and mcr-2) in urinary tract pathogens in Bangladesh: the last resort of infectious disease management colistin efficacy is under threat

Ara B, Urmi UL, Haque TA, Nahar S, Rumnaz A, Ali T, et al.

Expert Rev Clin Pharmacol, 2021 Apr;14(4):513-522.
PMID: 33691556 DOI: 10.1080/17512433.2021.1901577

Background: Currently, colistin-resistant pathogens emerged has become a global health concern. This study assessed the distribution of mcr-1 to mcr-5 variants with the phenotypic colistin-resistance in bacterial isolates from urinary tract infection (UTI) patients in Bangladesh.Methods: A cross-sectional study was conducted between April 2017 and March 2018 to enroll uncomplicated UTI patients, and 142 urine samples were analyzed. Uropathogens were identified using the API-20E biochemical panel and 16s rRNA gene sequencing. Polymerase chain reactions detected the mcr gene variants in the UTI isolates. The phenotypic colistin-susceptibility was determined by the Kirby-Bauer disc-diffusion method and the minimal inhibitory concentration (MIC) measurement.Results: The combined carriage of mcr-1 and mcr-2 genes in 11.4% (14/123) of urinary tract pathogens. The mcr-positive pathogens include five Escherichia coli, three Klebsiella pneumoniae, three Pseudomonas putida, two Enterobacter cloacae, and one Enterobacter hormaechei. The mcr-positive variant showed significantly higher phenotypic colistin resistance with MIC between >16 µg/mL and >128 µg/mL (p

Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Negative Bacteria/genetics; Gram-Negative Bacteria/isolation & purification; Gram-Negative Bacterial Infections/drug therapy*; Gram-Negative Bacterial Infections/microbiology
Organic and inorganic antibacterial approaches in combating bacterial infection for biomedical application

Saidin S, Jumat MA, Mohd Amin NAA, Saleh Al-Hammadi AS

Mater Sci Eng C Mater Biol Appl, 2021 Jan;118:111382.
PMID: 33254989 DOI: 10.1016/j.msec.2020.111382

In spite of antibiotics, antibacterial agents or specifically known as antiseptics are actively explored for the prevention of infection-associated medical devices. Antibacterial agents are introduced to overcome the complication of bacterial resistance which devoted by antibiotics. It can be classified into inorganic and organic, that prominently have impacted bacterial retardation in their own killing mechanism patterns. Therefore, this review paper aimed to provide information on most common used inorganic and organic antibacterial agents which have potential to be utilized in biomedical applications, thus, classifying the trends of antibacterial mechanism on Gram-negative and Gram-positive bacteria. In the beginning, infectious diseases and associated biomedical infections were stated to expose current infection scenarios on medical devices. The general view, application, susceptible bacteria and activation mechanism of inorganic (silver, copper, gold and zinc) and organic (chlorhexidine, triclosan, polyaniline and polyethylenimine) antibacterial agents that are widely proposed for biomedical area, were then gathered and reviewed. In the latter part of the study, the intact mechanisms of inorganic and organic antibacterial agents in retarding bacterial growth were classified and summarized based on its susceptibility on Gram-negative and Gram-positive bacteria. Most of inorganic antibacterial agents are in the form of metal, which release its ions to retard prominently Gram-negative bacteria. While organic antibacterial agents are susceptible to Gram-positive bacteria through organelle modification and disturbance of bio-chemical pathway. However, the antibacterial effects of each antibacterial agent are also depending on its effective mechanism and the species of bacterial strain. These compilation reviews and classification mechanisms are beneficial to assist the selection of antibacterial agents to be incorporated on/within biomaterials, based on its susceptible bacteria. Besides, the combination of several antibacterial agents with different susceptibilities will cover a wide range of antibacterial spectrum.

Matched MeSH terms: Gram-Negative Bacteria
Antimicrobial stewardship for acute-care hospitals: An Asian perspective

Apisarnthanarak A, Kwa AL, Chiu CH, Kumar S, Thu LTA, Tan BH, et al.

Infect Control Hosp Epidemiol, 2018 10;39(10):1237-1245.
PMID: 30227898 DOI: 10.1017/ice.2018.188

Inappropriate use of antibiotics is contributing to a serious antimicrobial resistance problem in Asian hospitals. Despite resource constraints in the region, all Asian hospitals should implement antimicrobial stewardship (AMS) programs to optimize antibiotic treatment, improve patient outcomes, and minimize antimicrobial resistance. This document describes a consensus statement from a panel of regional experts to help multidisciplinary AMS teams design programs that suit the needs and resources of their hospitals. In general, AMS teams must decide on appropriate interventions (eg, prospective audit and/or formulary restriction) for their hospital, focusing on the most misused antibiotics and problematic multidrug-resistant organisms. This focus is likely to include carbapenem use with the goal to reduce carbapenem-resistant gram-negative bacteria. Rather than initially trying to introduce a comprehensive, hospital-wide AMS program, it would be practical to begin by pilot testing a simple program based on 1 achievable core intervention for the hospital. AMS team members must work together to determine the most suitable AMS interventions to implement in their hospitals and how best to put them into practice. Continuous monitoring and feedback of outcomes to the AMS teams, hospital administration, and prescribers will enhance sustainability of the AMS programs.

Matched MeSH terms: Gram-Negative Bacteria
Phomopsidione nanoparticles coated contact lenses reduce microbial keratitis causing pathogens

Bin Sahadan MY, Tong WY, Tan WN, Leong CR, Bin Misri MN, Chan M, et al.

Exp Eye Res, 2019 01;178:10-14.
PMID: 30243569 DOI: 10.1016/j.exer.2018.09.011

Microbial keratitis is the infection caused by pathogenic microorganisms that commonly occurs among the contact lens users. Various antimicrobial compounds were coated on contact lenses to kill keratitis causing microorganisms, however these compounds caused several adverse side effects. Hence, the aim of this study is to develop a silicone hydrogel contact lens coated with phomopsidione nanoparticle that inhibit keratitis causing clinical isolates. Phomopsidione nanoparticles were synthesized using polyvinyl alcohol as encapsulant. The nanoparticles showed an average size of 77.45 nm, with neutral surface charge. Two drug release patterns were observed in the drug release profile, which are the initial slow release phase with extended drug release (release rate 46.65 μg/h), and the burst release phase observed on Day 2 (release rate 2224.49 μg/h). This well-regulated drug delivery system enables the control of drug release to meet the therapeutic requirements. On agar diffusion assay, 3 out of 5 test microorganisms were inhibited by phomopsidione nanoparticle coated contact lenses, including two Gram negative bacteria. Besides, all test microorganisms showed at least 99% of growth reduction, with the treatment of the contact lens model. The drug loaded onto the nanoparticles is sufficient to prevent the bacterial growth. In conclusion, this study provides an effective alternative to combat keratitis-causing microorganisms among contact wearers.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext A rare case of Ralstonia mannitolilytica infection in an end stage renal patient on maintenance dialysis during municipal water contamination

Lim CTS, Lee SE

Pak J Med Sci, 2017 10 27;33(4):1047-1049.
PMID: 29067090 DOI: 10.12669/pjms.334.13112

Ralstonia mannitolilytica is a gram negative soil bacterium. Ralstonia infection though rare, has become the emerging nosocomial pathogens in hospital settings. Various clinical manifestations had been described as well as the mode of transmission. Despite its low virulence factor, it is able to survive under harsh condition and this may potentially cause significant morbidity and mortality especially in immunocompromised patients. Outbreak of Ralstonia mannitolilytica infections in the hospital are typically associated with contaminated medical supplies or instruments. We described here a case of Ralstonia mannitolilytica infection in a dialysis patient that occurred during the municipal reservoir water contamination crisis. In this report, we will also describe the behaviour of Ralstonia genus and its 4 main species, namely R. pickettii, R. solanacearum, R. insidiosa, and R. mannitolilytica and the choices of antibiotic therapy based on literature review.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Interplay of the Quality of Ciprofloxacin and Antibiotic Resistance in Developing Countries

Sharma D, Patel RP, Zaidi STR, Sarker MMR, Lean QY, Ming LC

Front Pharmacol, 2017;8:546.
PMID: 28871228 DOI: 10.3389/fphar.2017.00546

Ciprofloxacin, a second generation broad spectrum fluoroquinolone, is active against both Gram-positive and Gram-negative bacteria. Ciprofloxacin has a high oral bioavailability and a large volume of distribution. It is used for the treatment of a wide range of infections including urinary tract infections caused by susceptible bacteria. However, the availability and use of substandard and spurious quality of oral ciprofloxacin formulations in the developing countries has been thought to have contributed toward increased risk of treatment failure and bacterial resistance. Therefore, quality control and bioequivalence studies of the commercially available oral ciprofloxacin formulations should be monitored. Appropriate actions should be taken against offending manufacturers in order to prevent the sale of substandard and spurious quality of ciprofloxacin formulations.

Matched MeSH terms: Gram-Negative Bacteria
Synthesis and characterization of gentamicin loaded ZSM-5 scaffold: Cytocompatibility and antibacterial activity

Nazemi N, Rajabi N, Aslani Z, Kharaziha M, Kasiri-Asgarani M, Bakhsheshi-Rad HR, et al.

J Biomater Appl, 2023 Jan;37(6):979-991.
PMID: 36454961 DOI: 10.1177/08853282221140672

Porous structure, biocompatibility and biodegradability, large surface area, and drug-loading ability are some remarkable properties of zeolite structure, making it a great possible option for bone tissue engineering. Herein, we evaluated the potential application of the ZSM-5 scaffold encapsulated GEN with high porosity structure and significant antibacterial properties. The space holder process has been employed as a new fabrication method with interconnected pores and suitable mechanical properties. In this study, for the first time, ZSM-5 scaffolds with GEN drug-loading were fabricated with the space holder method. The results showed excellent open porosity in the range of 70-78% for different GEN concentrations and appropriate mechanical properties. Apatite formation on the scaffold surface was determined with Simulation body fluid (SBF), and a new bone-like apatite layer shaping on all samples confirmed the in vitro bioactivity of ZSM-5-GEN scaffolds. Also, antibacterial properties were investigated against both gram-positive and gram-negative bacteria. The incorporation of various amounts of GEN increased the inhibition zone from 24 to 28 (for E. coli) and 26 to 37 (for S. aureus). In the culture with MG63 cells, great cell viability and high cell proliferation after 7 days of culture were determined.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Exploring Cefiderocol Resistance Mechanisms in Burkholderia pseudomallei

Hall CM, Somprasong N, Hagen JP, Nottingham R, Sahl JW, Webb JR, et al.

Antimicrob Agents Chemother, 2023 Jun 15;67(6):e0017123.
PMID: 37133377 DOI: 10.1128/aac.00171-23

Cefiderocol is a siderophore cephalosporin designed mainly for treatment of infections caused by β-lactam and multidrug-resistant Gram-negative bacteria. Burkholderia pseudomallei clinical isolates are usually highly cefiderocol susceptible, with in vitro resistance found in a few isolates. Resistance in clinical B. pseudomallei isolates from Australia is caused by a hitherto uncharacterized mechanism. We show that, like in other Gram-negatives, the PiuA outer membrane receptor plays a major role in cefiderocol nonsusceptibility in isolates from Malaysia.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext An intriguing approach toward antibacterial activity of green synthesized Rutin-templated mesoporous silica nanoparticles decorated with nanosilver

Abbasi M, Gholizadeh R, Kasaee SR, Vaez A, Chelliapan S, Fadhil Al-Qaim F, et al.

Sci Rep, 2023 Apr 12;13(1):5987.
PMID: 37046068 DOI: 10.1038/s41598-023-33095-1

In recent years, mesoporous silica nanoparticles (MSNs) have been applied in various biomedicine fields like bioimaging, drug delivery, and antibacterial alternatives. MSNs could be manufactured through green synthetic methods as environmentally friendly and sustainable synthesis approaches, to improve physiochemical characteristics for biomedical applications. In the present research, we used Rutin (Ru) extract, a biocompatible flavonoid, as the reducing agent and nonsurfactant template for the green synthesis of Ag-decorated MSNs. Transmission electron microscopy (TEM), zeta-potential, x-ray powder diffraction (XRD), fourier transform infrared (FTIR) spectroscopy analysis, scanning electron microscopy (SEM), brunauer-emmett-teller (BET) analysis, and energy-dispersive system (EDS) spectroscopy were used to evaluate the Ag-decorated MSNs physical characteristics. The antimicrobial properties were evaluated against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and also different types of candida. The cytotoxicity test was performed by using the MTT assay. Based on the findings, the significant antimicrobial efficacy of Ru-Ag-decorated MSNs against both gram positive and gram negative bacteria and different types of fungi was detected as well as acceptable safety and low cytotoxicity even at lower concentrations. Our results have given a straightforward and cost-effective method for fabricating biodegradable Ag-decorated MSNs. The applications of these MSNs in the domains of biomedicine appear to be promising.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Deacetylation of K481 and K484 on Penaeid Shrimp Hemocyanin Is Critical for Antibacterial Activity

Nie J, Aweya JJ, Yu Z, Zhou H, Wang F, Yao D, et al.

J Immunol, 2022 Aug 01;209(3):476-487.
PMID: 35851542 DOI: 10.4049/jimmunol.2200078

Although invertebrates' innate immunity relies on several immune-like molecules, the diversity of these molecules and their immune response mechanisms are not well understood. Here, we show that Penaeus vannamei hemocyanin (PvHMC) undergoes specific deacetylation under Vibrio parahaemolyticus and LPS challenge. In vitro deacetylation of PvHMC increases its binding capacity with LPS and antibacterial activity against Gram-negative bacteria. Lysine residues K481 and K484 on the Ig-like domain of PvHMC are the main acetylation sites modulated by the acetyltransferase TIP60 and deacetylase HDAC3. Deacetylation of PvHMC on K481 and K484 allows PvHMC to form a positively charged binding pocket that interacts directly with LPS, whereas acetylation abrogates the positive charge to decrease PvHMC-LPS attraction. Besides, V. parahaemolyticus and LPS challenge increases the expression of Pvhdac3 to induce PvHMC deacetylation. This work indicates that, during bacterial infections, deacetylation of hemocyanin is crucial for binding with LPS to clear Gram-negative bacteria in crustaceans.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Management and Mitigation of Vibriosis in Aquaculture: Nanoparticles as Promising Alternatives

Kah Sem NAD, Abd Gani S, Chong CM, Natrah I, Shamsi S

Int J Mol Sci, 2023 Aug 08;24(16).
PMID: 37628723 DOI: 10.3390/ijms241612542

Vibriosis is one of the most common diseases in marine aquaculture, caused by bacteria belonging to the genus Vibrio, that has been affecting many species of economically significant aquatic organisms around the world. The prevention of vibriosis in aquaculture is difficult, and the various treatments for vibriosis have their limitations. Therefore, there is an imperative need to find new alternatives. This review is based on the studies on vibriosis, specifically on the various treatments and their limitations, as well as the application of nanoparticles in aquaculture. One of the promising nanoparticles is graphene oxide (GO), which has been used in various applications, particularly in biological applications such as biosensors, drug delivery, and potential treatment for infectious diseases. GO has been shown to have anti-bacterial properties against both Gram-positive and Gram-negative bacteria, but no research has been published that emphasizes its impact on Vibrio spp. The review aims to explore the potential use of GO for treatment against vibriosis.

Matched MeSH terms: Gram-Negative Bacteria
Multifunctional and theranostic hydrogels for wound healing acceleration: An emphasis on diabetic-related chronic wounds

Tehrany PM, Rahmanian P, Rezaee A, Ranjbarpazuki G, Sohrabi Fard F, Asadollah Salmanpour Y, et al.

Environ Res, 2023 Dec 01;238(Pt 1):117087.
PMID: 37716390 DOI: 10.1016/j.envres.2023.117087

Hydrogels represent intricate three-dimensional polymeric structures, renowned for their compatibility with living systems and their ability to naturally degrade. These networks stand as promising and viable foundations for a range of biomedical uses. The practical feasibility of employing hydrogels in clinical trials has been well-demonstrated. Among the prevalent biomedical uses of hydrogels, a significant application arises in the context of wound healing. This intricate progression involves distinct phases of inflammation, proliferation, and remodeling, often triggered by trauma, skin injuries, and various diseases. Metabolic conditions like diabetes have the potential to give rise to persistent wounds, leading to delayed healing processes. This current review consolidates a collection of experiments focused on the utilization of hydrogels to expedite the recovery of wounds. Hydrogels have the capacity to improve the inflammatory conditions at the wound site, and they achieve this by diminishing levels of reactive oxygen species (ROS), thereby exhibiting antioxidant effects. Hydrogels have the potential to enhance the growth of fibroblasts and keratinocytes at the wound site. They also possess the capability to inhibit both Gram-positive and Gram-negative bacteria, effectively managing wounds infected by drug-resistant bacteria. Hydrogels can trigger angiogenesis and neovascularization processes, while also promoting the M2 polarization of macrophages, which in turn mitigates inflammation at the wound site. Intelligent and versatile hydrogels, encompassing features such as pH sensitivity, reactivity to reactive oxygen species (ROS), and responsiveness to light and temperature, have proven advantageous in expediting wound healing. Furthermore, hydrogels synthesized using environmentally friendly methods, characterized by high levels of biocompatibility and biodegradability, hold the potential for enhancing the wound healing process. Hydrogels can facilitate the controlled discharge of bioactive substances. More recently, there has been progress in the creation of conductive hydrogels, which, when subjected to electrical stimulation, contribute to the enhancement of wound healing. Diabetes mellitus, a metabolic disorder, leads to a slowdown in the wound healing process, often resulting in the formation of persistent wounds. Hydrogels have the capability to expedite the healing of diabetic wounds, facilitating the transition from the inflammatory phase to the proliferative stage. The current review sheds light on the biological functionalities of hydrogels, encompassing their role in modulating diverse mechanisms and cell types, including inflammation, oxidative stress, macrophages, and bacteriology. Additionally, this review emphasizes the significance of smart hydrogels with responsiveness to external stimuli, as well as conductive hydrogels for promoting wound healing. Lastly, the discussion delves into the advancement of environmentally friendly hydrogels with high biocompatibility, aimed at accelerating the wound healing process.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Antibacterial Activity of Myristica fragrans against Oral Pathogens

Shafiei Z, Shuhairi NN, Md Fazly Shah Yap N, Harry Sibungkil CA, Latip J

Evid Based Complement Alternat Med, 2012;2012:825362.
PMID: 23049613 DOI: 10.1155/2012/825362

Myristica fragrans Houtt is mostly cultivated for spices in Penang Island, Malaysia. The ethyl acetate and ethanol extracts of flesh, mace and seed of Myristica fragrans was evaluated the bactericidal potential against three Gram-positive cariogenic bacteria (Streptococcus mutans ATCC 25175, Streptococcus mitis ATCC 6249, and Streptococcus salivarius ATCC 13419) and three Gram-negative periodontopathic bacteria (Aggregatibacter actinomycetemcomitans ATCC 29522, Porphyromonas gingivalis ATCC 33277, and Fusobacterium nucleatum ATCC 25586). Antibacterial activities of the extracts was determined by twofold serial microdilution, with minimum inhibitory concentrations (MIC) ranging from 1.25 to 640 mg/mL and 0.075 to 40 mg/mL. The minimum bactericidal concentration (MBC) was obtained by subculturing method. Among all extracts tested, ethyl acetate extract of flesh has the highest significant inhibitory effects against Gram-positive and Gram-negative bacteria with mean MIC value ranging from 0.625 to 1.25 ± 0.00 (SD) mg/mL; P = 0.017) and highest bactericidal effects at mean MBC value ranging from 0.625 mg/mL to 20 ± 0.00 (SD) mg/mL. While for seed and mace of Myristica fragrans, their ethanol extracts exhibited good antibacterial activity against both groups of test pathogens compared to its ethyl acetate extracts. All of the extracts of Myristica fragrans did not show any antibacterial activities against Fusobacterium nucleatum ATCC 25586. Thus, our study showed the potential effect of ethyl acetate and ethanol extracts from flesh, seed and mace of Myristica fragrans to be new natural agent that can be incorporated in oral care products.

Matched MeSH terms: Gram-Negative Bacteria
Effects of Methanol Extract of Wedelia chinensis Osbeck (Asteraceae) Leaves against Pathogenic Bacteria with Emphasise on Bacillus cereus

Darah I, Lim SH, Nithianantham K

Indian J Pharm Sci, 2013 Sep;75(5):533-9.
PMID: 24403653

The antibacterial activity of the methanol extract of Wedelia chinensis leave was studied and tested against three pathogenic Gram positive bacteria (Bacillus cereus, B. subtilis and Stapylococcus aureus) and three pathogenic Gram negative bacteria (Escherichia coli, Proteus rettgeri and Pseudomonas aeruginosa) by the disk diffusion assay and broth dilution methods. The extract exhibited favourable antibacterial activity against the bacterial cells but was more potent against Gram positive bacteria with the minimum inhibition concentration of 3.12 to 6.25 mg/ml compared to the Gram negative bacteria which had minimum inhibition concentration values of 25 mg/ml. The time-kill study suggested that the extract possessed bactericidal properties at higher concentrations and eradicated the growth of bacterial cells. The major abnormalities occurred to the bacterial cells after exposed to the extract were complete alterations in their morphology and collapsed of the cells beyond repair. The methanol extract of W. chinensis may be an effective antibacterial agent to treat bacterial infections.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Preliminary screening of endophytic fungi from medicinal plants in malaysia for antimicrobial and antitumor activity

Radu S, Kqueen CY

Malays J Med Sci, 2002 Jul;9(2):23-33.
PMID: 22844221 MyJurnal

The screening of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeast and fungi was carried out on isopropanol extracts prepared from 121 isolates of endophytic fungi isolated from medicinal plants in Malaysia. Sensitivity was found to vary among the microorganisms. Bacillus subtilis, Saccharomyces cerevisiae and Alternaria sp. were susceptible to extracts from three, two and two isolates of endophytic fungi, respectively. None were found effective against Salmonella typhimurium. Sixteen endophytic fungal isolates tested were also found to exhibit antitumor activity in the yeast cell-based assay.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Evaluation of anti-bacterial and anti-oxidant potential of andrographolide and echiodinin isolated from callus culture of Andrographis paniculata Nees

Arifullah M, Namsa ND, Mandal M, Chiruvella KK, Vikrama P, Gopal GR

Asian Pac J Trop Biomed, 2013 Aug;3(8):604-10; discussion 609-10.
PMID: 23905016 DOI: 10.1016/S2221-1691(13)60123-9

To evaluate the anti-bacterial and anti-oxidant activity of andrographolide (AND) and echiodinin (ECH) of Andrographis paniculata.

Matched MeSH terms: Gram-Negative Bacteria/drug effects
Fulltext A pentaplex PCR assay for the detection and differentiation of Shigella species

Ojha SC, Yean Yean C, Ismail A, Singh KK

Biomed Res Int, 2013;2013:412370.
PMID: 23509722 DOI: 10.1155/2013/412370

The magnitude of shigellosis in developing countries is largely unknown because an affordable detection method is not available. Current laboratory diagnosis of Shigella spp. is laborious and time consuming and has low sensitivity. Hence, in the present study, a molecular-based diagnostic assay which amplifies simultaneously four specific genes to identify invC for Shigella genus, rfc for S. flexneri, wbgZ for S. sonnei, and rfpB for S. dysenteriae, as well as one internal control (ompA) gene, was developed in a single reaction to detect and differentiate Shigella spp. Validation with 120 Shigella strains and 37 non-Shigella strains yielded 100% specificity. The sensitivity of the PCR was 100 pg of genomic DNA, 5.4 × 10(4) CFU/ml, or approximately 120 CFU per reaction mixture of bacteria. The sensitivity of the pentaplex PCR assay was further improved following preincubation of the stool samples in gram-negative broth. A preliminary study with 30 diarrhoeal specimens resulted in no cross-reaction with other non-Shigella strains tested. We conclude that the developed pentaplex PCR assay is robust and can provide information about the four target genes that are essential for the identification of the Shigella genus and the three Shigella species responsible for the majority of shigellosis cases.

Matched MeSH terms: Gram-Negative Bacteria/isolation & purification
Biological properties of sodium alkyl methyl ester sulfonate/alkyltrimethylammonium bromide surfactant mixtures

Wong SP, Lim WH, Cheng SF, Chuah CH

Colloids Surf B Biointerfaces, 2012 Jan 1;89:48-52.
PMID: 21937202 DOI: 10.1016/j.colsurfb.2011.08.021

Quaternary ammonium compounds (QACs) are commonly used as disinfectant in medical care, food industry, detergents and glue industries. This is due to a small concentration of QACs is sufficient to inhibit the growth of various bacteria strains. In this work, the inhibitive power of cationic surfactants, alkyltrimethylammonium bromide (C(n)TAB) in the presence of anionic surfactants, sodium alkyl methyl ester α-sulfonate (C(n)MES) was studied. The growth inhibition test with gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria were used to determine the toxicity of single and mixed surfactants. Results from this work showed that certain mixed surfactants have lower minimum inhibition concentration (MIC) as compared to the single C(n)TAB surfactants. Besides that, it was also found that alkyl chain length and the mixing ratios of the surfactants play a significant role in determining the mixture inhibitive power.

Matched MeSH terms: Gram-Negative Bacteria/drug effects

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