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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
Fulltext Bioactive compounds and biological activities of Jatropha curcas L. kernel meal extract

Oskoueian E, Abdullah N, Ahmad S, Saad WZ, Omar AR, Ho YW

Int J Mol Sci, 2011;12(9):5955-70.
PMID: 22016638 DOI: 10.3390/ijms12095955

Defatted Jatropha curcas L. (J. curcas) seed kernels contained a high percentage of crude protein (61.8%) and relatively little acid detergent fiber (4.8%) and neutral detergent fiber (9.7%). Spectrophotometric analysis of the methanolic extract showed the presence of phenolics, flavonoids and saponins with values of 3.9, 0.4 and 19.0 mg/g DM, respectively. High performance liquid chromatography (HPLC) analyses showed the presence of gallic acid and pyrogallol (phenolics), rutin and myricetin (flavonoids) and daidzein (isoflavonoid). The amount of phorbol esters in the methanolic extract estimated by HPLC was 3.0 ± 0.1 mg/g DM. Other metabolites detected by GC-MS include: 2-(hydroxymethyl)-2 nitro-1,3-propanediol, β-sitosterol, 2-furancarboxaldehyde, 5-(hydroxymethy) and acetic acid in the methanolic extract; 2-furancarboxaldehyde, 5-(hydroxymethy), acetic acid and furfural (2-furancarboxaldehyde) in the hot water extract. Methanolic and hot water extracts of kernel meal showed antimicrobial activity against both Gram positive and Gram negative pathogenic bacteria (inhibition range: 0-1.63 cm) at the concentrations of 1 and 1.5 mg/disc. Methanolic extract exhibited antioxidant activities that are higher than hot water extract and comparable to β-carotene. The extracts tended to scavenge the free radicals in the reduction of ferric ion (Fe(3+)) to ferrous ion (Fe(2+)). Cytotoxicity assay results indicated the potential of methanolic extract as a source of anticancer therapeutic agents toward breast cancer cells.

Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Negative Bacteria/growth & development
Growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of Lactobacillus upon ultraviolet radiation

Yeo SK, Liong MT

Int J Food Sci Nutr, 2012 Nov;63(7):821-31.
PMID: 22264088 DOI: 10.3109/09637486.2011.652942

The objective of this study was to evaluate the effects of ultraviolet (UV) radiation (UVB; 90 J/m²) on growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of L. casei FTDC 2113. UV radiation significantly enhanced (P < 0.05) the growth of parent cells in mannitol-soymilk fermented at 37°C for 24 h. This had led to an enhanced intracellular and extracellular β-glucosidase activity with a subsequent increase in bioconversion of isoflavones in mannitol-soymilk (P < 0.05). UV radiation also promoted (P < 0.05) the tolerance of parent cells towards acidic condition (pH 2 and 3) and intestinal bile salts (oxgall, taurocholic and cholic acid). In addition, parent treated cells also exhibited better (P < 0.05) adhesion ability to mucin and antimicrobial activity compared to that of the control. All these positive effects of UV radiation were only prevalent in the parent cells without inheritance by first, second and third passage of cells. Although temporary, our results suggested that UV radiation could enhance the bioactive and probiotic potentials of L. casei FTDC 2113, and thus could be applied for the production of probiotic products with enhanced bioactivity.

Matched MeSH terms: Gram-Negative Bacteria/growth & development
Fulltext Treatment of clinical solid waste using a steam autoclave as a possible alternative technology to incineration

Hossain MS, Balakrishnan V, Rahman NN, Sarker MZ, Kadir MO

Int J Environ Res Public Health, 2012 Mar;9(3):855-67.
PMID: 22690168 DOI: 10.3390/ijerph9030855

A steam autoclave was used to sterilize bacteria in clinical solid waste in order to determine an alternative to incineration technology in clinical solid waste management. The influence of contact time (0, 5, 15, 30 and 60 min) and temperature (111 °C, 121 °C and 131 °C) at automated saturated steam pressure was investigated. Results showed that with increasing contact time and temperature, the number of surviving bacteria decreased. The optimum experimental conditions as measured by degree of inactivation of bacteria were 121 °C for 15 minutes (min) for Gram negative bacteria, 121 °C and 131 °C for 60 and 30 min for Gram positive bacteria, respectively. The re-growth of bacteria in sterilized waste was also evaluated in the present study. It was found that bacterial re-growth started two days after the inactivation. The present study recommends that the steam autoclave cannot be considered as an alternative technology to incineration in clinical solid waste management.

Matched MeSH terms: Gram-Negative Bacteria/growth & development
Surveillance study of bacteraemic episodes in febrile neutropenic children

Ariffin H, Navaratnam P, Lin HP

Int J Clin Pract, 2002 May;56(4):237-40.
PMID: 12074201

We prospectively studied the type, frequency and outcome of infections in 513 patients with 762 consecutive episodes of febrile neutropenia (FN) over a five-year period between 1995 and 1999 in a single paediatric oncology unit. The findings were then compared with a similar study carried out in our unit between 1990 and 1994. The types of bacterial isolates and sensitivity patterns were also studied to identify trends and to gauge the suitability of antibiotics chosen for empirical therapy. Bacteraemia was documented in 35.4% of FN episodes, although 70% of patients did not have an obvious site of sepsis. The majority of isolates (61.9%) were gram-negative bacteria, a consistent finding throughout the study period. Resistance to ceftazidime, amikacin and imipenem among gram-negative bacteria was 26.3%, 21.2% and 0.7%, respectively. Methicillin resistance among gram-positive bacteria was 26.3%, while no vancomycin-resistant bacteria were encountered. There were 36 sepsis-related deaths. Factors associated with a fatal outome were prolonged capillary refill time, hypotension, fever above 39 degrees C and pneumonia. Rapid neutrophil recovery was associated with a good prognosis. A change to our current choice of empirical antibiotics for FN, comprising ceftazidime/ceftriaxone and amikacin appears necessary because of the relatively high resistance rates found.

Matched MeSH terms: Gram-Negative Bacteria/isolation & purification*
Synthesis of ZnO nanoparticles with chitosan as stabilizing agent and their antibacterial properties against Gram-positive and Gram-negative bacteria

Yusof NAA, Zain NM, Pauzi N

Int J Biol Macromol, 2019 Mar 01;124:1132-1136.
PMID: 30496864 DOI: 10.1016/j.ijbiomac.2018.11.228

Antibacterial activity of zinc oxide (ZnO) nanoparticles have received significant interest, particularly by the implementation of nanotechnology to synthesize particles in nanometer region. ZnO nanoparticles were successfully synthesized through microwave heating by using chitosan as a stabilizing agent and characterized by UV-vis, FTIR, XRD and FESEM-EDX. The aim of the present study is to determine the antibacterial activity of ZnO nanoparticles against Gram-positive bacterium Staphylococcus aureus (S. aureus) and Gram-negative bacterium Escherichia coli (E. coli). The antibacterial effect of ZnO nanoparticles was investigated for the inhibition zone and inactivation of cell growth. The absorption of ZnO nanoparticles was found to be around 360 nm. FTIR results showed the stretching mode of ZnO nanoparticles at 475 cm-1 of the absorption band. EDX results indicated that ZnO nanoparticles have been successfully formed with an atomic percentage of zinc and oxygen at 23.61 and 46.57% respectively. X-ray diffraction result was confirmed the single-phase formation of ZnO nanoparticles and the particle sizes were observed to be around 50 to 130 nm. The results showed that ZnO nanoparticles have displayed inhibition zone of 16 and 13 mm against S. aureus and E. coli respectively. Gram-negative bacteria seemed to be more resistant to ZnO nanoparticles than Gram-positive bacteria.

Matched MeSH terms: Gram-Negative Bacteria
Epidemiology and trends in the antibiotic susceptibilities of Gram-negative bacilli isolated from patients with intra-abdominal infections in the Asia-Pacific region, 2010-2013

Chang YT, Coombs G, Ling T, Balaji V, Rodrigues C, Mikamo H, et al.

Int J Antimicrob Agents, 2017 Jun;49(6):734-739.
PMID: 28435019 DOI: 10.1016/j.ijantimicag.2017.01.030

This study was conducted to investigate the epidemiology and antimicrobial susceptibility patterns of Gram-negative bacilli (GNB) isolated from intra-abdominal infections (IAIs) in the Asia-Pacific region (APR) from 2010-2013. A total of 17 350 isolates were collected from 54 centres in 13 countries in the APR. The three most commonly isolated GNB were Escherichia coli (46.1%), Klebsiella pneumoniae (19.3%) and Pseudomonas aeruginosa (9.8%). Overall, the rates of extended-spectrum β-lactamase (ESBL)-producing E. coli and K. pneumoniae were 38.2% and 24.3%, respectively, and they were highest in China (66.6% and 38.7%, respectively), Thailand (49.8% and 36.5%, respectively) and Vietnam (47.9% and 30.4%, respectively). During 2010-2013, the rates of ESBL-producing E. coli and K. pneumoniae isolates causing community-associated (CA) IAIs (collected <48 h after admission) were 26.0% and 13.5%, respectively, and those causing hospital-associated (HA) IAIs were 48.0% and 30.6%, respectively. Amikacin, ertapenem and imipenem were the most effective agents against ESBL-producing isolates. Piperacillin/tazobactam displayed good in vitro activity (91.4%) against CA ESBL-producing E. coli. For other commonly isolated Enterobacteriaceae, fluoroquinolones, cefepime and carbapenems exhibited better in vitro activities than third-generation cephalosporins. Amikacin possessed high in vitro activity against all GNB isolates (>80%) causing IAIs, except for Acinetobacter calcoaceticus-baumannii (ACB) complex (30.9% for HA-IAI isolates). All of the antimicrobial agents tested exhibited <45% in vitro activity against ACB complex. Antimicrobial resistance is a persistent threat in the APR and continuous monitoring of evolutionary trends in the susceptibility patterns of GNB causing IAIs in this region is mandatory.

Matched MeSH terms: Gram-Negative Bacteria/drug effects*; Gram-Negative Bacteria/isolation & purification; Gram-Negative Bacterial Infections/microbiology*; Gram-Negative Bacterial Infections/epidemiology*
Infections by multidrug-resistant Gram-negative Bacteria: What's new in our arsenal and what's in the pipeline?

Koulenti D, Song A, Ellingboe A, Abdul-Aziz MH, Harris P, Gavey E, et al.

Int J Antimicrob Agents, 2019 Mar;53(3):211-224.
PMID: 30394301 DOI: 10.1016/j.ijantimicag.2018.10.011

The spread of multidrug-resistant bacteria is an ever-growing concern, particularly among Gram-negative bacteria because of their intrinsic resistance and how quickly they acquire and spread new resistance mechanisms. Treating infections caused by Gram-negative bacteria is a challenge for medical practitioners and increases patient mortality and cost of care globally. This vulnerability, along with strategies to tackle antimicrobial resistance development, prompts the development of new antibiotic agents and exploration of alternative treatment options. This article summarises the new antibiotics that have recently been approved for Gram-negative bacterial infections, looks down the pipeline at promising agents currently in phase I, II, or III clinical trials, and introduces new alternative avenues that show potential in combating multidrug-resistant Gram-negative bacteria.

Matched MeSH terms: Gram-Negative Bacteria/drug effects*; Gram-Negative Bacteria/isolation & purification; Gram-Negative Bacterial Infections/drug therapy; Gram-Negative Bacterial Infections/microbiology*; Gram-Negative Bacterial Infections/epidemiology*
The state of ESKAPE in Malaysia

McNeil HC, Lean SS, Lim V, Clarke SC

Int J Antimicrob Agents, 2016 Nov;48(5):578-579.
PMID: 27742200 DOI: 10.1016/j.ijantimicag.2016.08.011
Matched MeSH terms: Gram-Negative Bacteria/drug effects*; Gram-Negative Bacteria/isolation & purification; Gram-Negative Bacterial Infections/microbiology; Gram-Negative Bacterial Infections/epidemiology*
Fulltext An investigation into the synergistic relationship between Lactoferrin and Azithromycin with particular reference to Periodontopathic bacteria

Juzaily Husain

International Medical Journal Malaysia, 2017;16(21):50-50.
MyJurnal

The development of treatment strategies for periodontitis that maximise the
effectiveness of antibiotics is highly desirable. Azithromycin is proving to be an effective antibiotic
for treatment of refractory periodontitis which works by binding to the outer membrane of Gramnegative bacteria and subsequently inhibits protein synthesis. Lactoferrin is a membrane-active
host antimicrobial protein and so the objective of this study was to determine whether the effect
of azithromycin (AZM) against example periodontopathogens (Porphyromonas gingivalis and
Tannerella forsythia) could be potentiated by lactoferrin. (Copied from article).

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Synergistic effects of Persicaria odorata (daun kesom) leaf extracts with standard antibiotics on pathogenic bacteria

Ridzuan, P.M., Hairul Aini Hamzah, Anis Shah, Norazian Mohd Hassan, Baharudin Roesnita

International Medical Journal Malaysia, 2017;16(2):27-32.
MyJurnal

Antibacterial activity of different types of P. odorata leaf extracts was evaluated in combination with
standard antibiotics. Persicaria. odorata leaves were extracted with n-hexane (n-hex), dichloromethane
(DCM) and methanol (MeOH). Each extract was applied on vancomycin (30µg), erythromycin (15µg) and
gentamicin (10µg) discs, respectively. Disk diffusion method was used to evaluate the synergistic activity of
each combination on Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes,
Streptococcus pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, and Escherichia coli. Minimum
inhibitory concentration (MIC) and gas chromatography mass spectrometry (GCMS) analysis was performed on
the active extract. Synergistic effects seen were mainly from the n-hex+antibiotics combinations, mainly on
the Gram-positive bacteria (7 additive, 5 antagonistic), with MIC range from 50 µg/ml to 100 µg/ml, as well
as Gram-negative bacteria (2 additive, 2 indifferent, 5 antagonistic). In particular, synergism showed by the
combination of n-hex+van were all additive against the susceptible bacteria. DCM extract combination
showed synergistic effects on three Gram-positive species (S. aureus, S. epidermidis, S. pyogenes).
Meanwhile, MeOH+antibiotics combination showed significant additive synergistic effects (p

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Screening of selected Malaysian plants against several food borne pathogen bacteria

International Food Research Journal, 2011;18(3):1195-1201.
MyJurnal

This study was conducted to evaluate antimicrobial properties of ethanolic extracts of the leaves of Nephelium lappaceum, Curcuma longa, Cinnamomun cassia, Durio zibethinus, Vitex trifolia, Amaranthus tricolor, Syzygium samarangense and Manihot esculenta. Antibacterial properties of the extracts were studied against fifteen strains of different gram positive and gram negative pathogenic bacteria, including Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Vibrio para, and Escherichia coli using the agar disk diffusion method. Among the tested extracts, only Amaranthus tricolor exhibited specific inhibition of one of the tested bacteria; Bacillus cereus. Using the microdilution method, its minimum inhibitory concentration (MIC) value was determined to be 20 mg/mL.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext The distribution and characteristics of bacteria in recreational river water of a community resort in Baram, Sarawak, Malaysian Borneo

Lihan, S., Tian, P.K,, Chiew, T.S., Ching, C.L., Shahbudin, A., Hussain, H., et al.

International Food Research Journal, 2017;24(5):2238-2245.
MyJurnal

Enterobacteriaceae is a large family within the Gram-negative bacteria that primarily inhabits in the gastrointestinal tract of human and animals. The bacteria within this group are readily survived in the environment with some species found living free in the water where energy sources are scarce, making them ideal indicators for faecal contamination of the river water. Some species within the family have been used as indicator for the presence of pathogenic bacteria whilst on the other hand some species have been directly associated with various diseases in human and animals. The main aim of this research study was to determine the distribution and characteristics of the Enterobacteriaceae in water samples collected from river and waterfalls within a community resort. The health risk associated with the bacteria was analysed with regard to their susceptibility to antibiotics. Samples were collected from surface water and water falling down directly from waterfalls of river within the community resort. The samples collected were plated onto Eosine Methylene Blue agar (EMBA) for the isolation of the Enterobacteriaceae. Bacterial colonies growing on the agar were randomly picked, purified, stocked and then identified using API 20E identification kit. DNA fingerprinting using (GTG)5-PCR was utilised to determine their genetic profiles before the isolates were grouped into a dendrogram using RAPDistance software package. The level of antibiotic susceptibility of the bacteria isolates was analysed using disc diffusion technique. This study confirmed the presence of Enterobacter, Klebsiella, Citrobacter, Pantoea and Serratia in the water samples with their single and multiple antibiotic resistance and susceptible characteristics. The dendrogram presented in this study shows genetic similarities and differences among the strains, suggesting while there is a potential for single distribution of a clone, there is also possibility of the distribution of different strains within species in the water environment. Therefore, awareness on the potential risk associated with genetically diverse intermediate and resistant enteric bacteria in the recreational water should be communicated to the public especially communities within the study area.

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
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 comparative analysis of antibacterial effects of activated and non-activated of expired platelet concentrate by disc diffusion method

Zabidi MA, Yusoff NM, Kader ZS

Indian J Pathol Microbiol, 2012 Jan-Mar;55(1):47-51.
PMID: 22499300 DOI: 10.4103/0377-4929.94855

Platelets release more than 30 cytokines to provide primary hemostatic function. In addition, platelets are also known to release antimicrobial peptides upon activation by thrombin.

Matched MeSH terms: Gram-Negative Bacteria/drug effects*
Bacterial dynamics associated with algal antibacterial substances during post harvest desiccation process of Sargassum stolonifolium Phang et Yoshida

Vairappan CS

Indian J Exp Biol, 2003 Aug;41(8):837-45.
PMID: 15248481

Brown algae of genus Sargassum are known to produce relatively higher amount of alginic acid. Optimal extraction of this algalcolloid for local consumption requires in-depth studies on post-harvest treatment of the algal fronds. Present investigation endeavors to establish the dynamics and inter-relationship of moisture content and bacteria found on the surface of the alga and alginic acid content during post-harvest desiccation of Sargassum stolonifolium Phang et Yoshida. Harvested fronds were subjected to desiccation for 31 days and bacterial dynamics were monitored with relation to moisture content and water activity index (a(w)). There was 85% decrease in moisture content, however, a(w) showed a more gradual decrease. Total bacterial count increased during the first week and attained maximal value on day 7. Thereafter, a drastic decrease was seen until day 14, followed by a gradual decline. Six species of bacteria were isolated and identified, i.e. Azomonas punctata, Azomonas sp., Escherichia coli, Micrococcus sp., Proteus vulgaris and Vibrio alginolyticus. Calculated ratios for increase in alginic acid content and decrease in moisture content were almost the same throughout the desiccation process, implying that extracellular alginase-producing bacteria did not use the alginic acid produced by the algae as its carbon source. It became apparent that drastic decrease in bacterial count after day 7 could not be attributed to salinity, moisture content, a(w) or lack of carbon source for the bacteria. The possible exposure of these bacteria to algal cell sap which is formed due to the rupture of algal cells was seen as the most likely reason for the drop in bacterial population. Scanning electron microscope (SEM) micrograph taken on day 10 of desiccation showed the presence of cracks and localities where bacteria were exposed to algal cell sap. In vitro antibacterial tests were carried out to verify the effect of algal extracts. Separation and purification of crude algal extracts via bioassay guided separation methodology revealed the identity of active compounds (i.e. gylcolipids and free fatty acids) involved in this inherently available antibacterial defense mechanism during algal desiccation.

Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Negative Bacteria/growth & development
Fulltext Medicinal properties screening of Mallotus paniculatus extract

NA Bahaman, Raha Ahmad Raus, Yusilawati Ahmad Nor, Al Mamun, Abdullah, Noor Suhana Adzahar, Dayang Fredalina Basri

IIUM Medical Journal Malaysia, 2020;19(1):5-12.
MyJurnal

Introduction: Traditionally, Mallotus paniculatus (Balik Angin) plant is used in the treatment of various
diseases in rural areas such as remedy after childbirth, wound healing and fever. In this present study, four
medicinal properties of the plant were investigated which included antibacterial, antifungal, anticancer and
antioxidant activities. Materials and Methods: Potential medicinal compounds were extracted from the plant
leaves by sonication with 3 different solvents namely ethanol, ethyl acetate and hexane respectively. The
antibacterial and antifungal properties were determined using disc diffusion agar and broth dilution assay,
the antioxidant activity by DPPH scavenging assay and the anticancer effect by MTT assay. Results: From the
screening of the medicinal properties, M. paniculatus leave extracts were shown to possess antibacterial,
antioxidant and anticancer properties but not antifungal properties. Ethanolic and ethyl acetate extracts of
the leave were active against gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) but not
gram negative bacteria (Pseudomonas aeruginosa and Escherichia coli). The antioxidant activity of the
ethanolic crude extract was high; with IC50 of 30 μg/ml comparable with the positive controls; ascorbic acid
and butylated hydroxytoluene (BHT). Both ethanolic and ethyl acetate extracts were cytotoxic against breast
cancer (MCF7), colon cancer (HT-29), cervix cancer (Hela) cell lines. Conclusion: M. paniculatus leave
extract has many potential medicinal values for further studies.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Autoclave-assisted synthesis of AgNPs in Z. officinale extract and assessment of their cytotoxicity, antibacterial and antioxidant activities

Kalantari K, Afifi AM, Moniri M, Moghaddam AB, Kalantari A, Izadiyan Z

IET Nanobiotechnol, 2019 May;13(3):262-268.
PMID: 31053688 DOI: 10.1049/iet-nbt.2018.5066

In this study, the authors synthesised silver nanoparticles (AgNPs) using autoclave as a simple, unique and eco-friendly approach. The effect of Zingiber officinale extract was evaluated as a reducing and stabiliser agent. According to transmission electron microscopy results, the AgNPs were in the spherical shape with a particle size of ∼17 nm. The biomedical properties of AgNPs as antibacterial agents and free radical scavenging activity were estimated. Synthesised AgNPs showed significant 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging. Strong bactericidal activity was shown by the AgNPs on Gram-positive and Gram-negative bacteria. A maximum inhibition zone of ∼14 mm was obtained for epidermidis at a concentration of 60 μg/ml for sample fabricated at 24 h. The AgNPs also showed a significant cytotoxic effect against MCF-7 breast cancer cell lines with an half maximal inhibitory concentration value of 62 μg/ml in 24 h by the MTT assay. It could be concluded that Z. officinale extract can be used effectively in the production of potential antioxidant and antimicrobial AgNPs for commercial application.

Matched MeSH terms: Gram-Negative Bacteria/drug effects
Antibiotic resistance and sensitivity pattern of Metallo-β-Lactamase Producing Gram-Negative Bacilli in ventilator-associated pneumonia in the intensive care unit of a public medical school hospital in Bangladesh

Nusrat T, Akter N, Rahman NAA, Godman B, D Rozario DT, Haque M

Hosp Pract (1995), 2020 Aug;48(3):128-136.
PMID: 32271642 DOI: 10.1080/21548331.2020.1754687

BACKGROUND: Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in intensive care units (ICU), accounting for 25% of all ICU infections. Antimicrobial resistance is increasing and becoming a significant health problem worldwide, increasing hospital length of stay, mortality and costs. Identifying antibiotic resistance patterns in VAP is important as this can cause outbreaks in ICUs. To date, there have been limited studies assessing this in Bangladesh. Consequently, the primary objective of this research was to study the species of bacterial growth and to determine the antibiotic resistance patterns of Metallo-β-Lactamase (MBL) producing gram-negative bacilli among ICU patients with VAP in a public medical school hospital, Bangladesh. In addition, identify the factors associated with a positive culture to provide future guidance.
METHOD: Cross-sectional study performed in the Chattogram Medical College Hospital, Bangladesh. Mueller Hinton agar plates were used for antibiotic sensitivity testing by the Kirby-Buer disc diffusion test.
RESULTS: Among 105 clinically suspected VAP cases, qualitative cultures were positive in 95 (90%) of them. The most common bacteria identified were Acinetobacter spp. (43.2%), Klebsiella spp. (20%) and Pseudomonas spp. (18.9%). A positive culture was not associated with patients' age or gender. Among 41 isolated Acinetobacter spp., 38 (92.7%) were resistant to gentamicin followed by 36 (87.8%) to ceftriaxone. Among 24 isolated Klebsiella spp., 22 (83.3%) were resistant to ceftriaxone. Among 18 isolated Pseudomonas spp., 16 (88.8%) were resistant to ciprofloxacin, and 13 (72.2%) were resistant to ceftriaxone. Among nine isolated E.coli, all were resistant to ceftriaxone and ciprofloxacin. All four Proteus spp. (100%) isolated were resistant to ciprofloxacin. Additionally, phenotype MBL producing was 65.22% and genotype was 45.65% among imipenem resistant pathogens. Imipenem resistant pathogens were sensitive to amoxyclav, amikacin¸ azithromycin, ceftazidime, ceftriaxone, colistin and gentamycin.
CONCLUSION: A positive culture was detected in 90% of VAP patients, but it was not associated with the patients' age and gender. The most common bacteria identified were Acinetobacter spp., Klebsiella spp. and Pseudomonas spp., where the majority of these were resistant to ceftriaxone. The results are being used to provide future guidance on the empiric management of VAP in this hospital.

Matched MeSH terms: Gram-Negative Bacteria/isolation & purification*

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