Shigella Boydii Research Articles

Transmission pathway of Enterobacteriaceae from reared fish and surrounding environment to water body in Batang Ai reservoir, Sarawak, Borneo

This study was aimed to determine the genetic distribution and characteristics of the bacterial family in the Batang Ai reservoir and their possible sources of transmission into the lake water. Surface water samples were collected from twenty-seven sampling points scattered around the Batang Ai reservoir and four fish samples were obtained from an aquaculture farm located within the water reservoir. The samples were plated on Violet Red Bile Agar (VRBA) plates for the isolation of Enterobacteriaceae. A total of 141 bacterial colonies were isolated from the culture plates and subjected to (GTG)5 PCR analysis to determine the genetic similarities among the isolates. A dendrogram was plotted based on the (GTG)5 PCR patterns and the representative isolates were selected for identity confirmation using 16S rRNA sequencing. Based on the sequencing, five genera of Enterobacteriaceae were identified as Enterobacter, Escherichia, Shigella, Klebsiella and Pseudocitrobacter, consisting of 12 identified species, namely Enterobacter hormaechei, E. hormaechei subsp. xiangfangensis, E. cloacae, E. cloacae subsp. dissolvens, E. kobei, E. tabaci, Shigella boydii, S. flexneri, Pseudocitrobacter faecalis, Escherichia fergusonii, E. coli and Klebsiella pneumoniae. A total of 14 antibiotics from seven anti-microbial classes including penicillins, cephems, monobactams, aminoglycosides, tetracyclines, quinolones and fluoroquinolones, and phenicols were tested against the isolates. A total of seven species within the isolates were found to have multiple antibiotic resistance (MAR) index below 0.2, suggesting those isolates were derived from low risk of antibiotics contamination sources. With the exception of ampicillin and tetracycline, all antibiotics have 25% or less bacterial species displaying resistance. Most (70%) of the bacterial species showed resistance toward ampicillin. The fish isolates demonstrated multiple antibiotic resistance indexes ranging from 0.214 to 0.5. The presence of multiple antibiotic-resistant bacteria in the water reservoir may pose the risk of antibiotic-resistant bacterial infections through water-related activities and consumption of fish harbouring antimicrobial resistance bacterial species. It was proven that Enterobacteriaceae were transmitted from the activities and surrounding environments to the water reservoir, thus it is proposed that a guideline for activities to be carried out in the water reservoir is created and imposed.

STUDIES ON ANTIBACTERIAL ACTIVITY OF ACACIA NILOTICA

This study was conducted as the first step to explore the possibility of isolating active ingredient(s) of Acacia nilotica as antibacterial agents. Two types of extracts from air-dried Acacia nilotica leaves were prepared through solvent extraction method using methanol and hexane. The disc diffusion method was used to screen 10 different pathogenic bacteria for their sensitivity to the leaf extracts. Acacia nilotica was found to be effective against Salmonella typhi, Shigella boydii, Shigella flexneri, Shigella sonnei, Vibrio cholerae 0139 and Hafnia. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these extracts were determined. In case of methanol extract, the MIC values were 700mg ml-1 against Salmonella typhi and 800 mg ml-1 for each of Shigella boydii, and Shigella flexneri , whereas the corresponding MIC values for hexane extract were found 800, 800 and 900 mg ml-1 respectively. The MBC values of methanol extract were found to be 800 mg ml-1 for Salmonella typhi, 900 mg ml-1 against each of Shigella boydii and Shigella flexneri and in case of hexane extract the MBC values were found 900, 1000 and 1200 mg ml-1 respectively.

Zoonotic Bacteria Harboring in Goat Intestine: A One Health Perspective

The risk of zoonosis transmission when handling livestock or animal products is substantial, ‘One Health’ interventions should be an effective strategy for the control of many zoonotic bacteria. In this study, 26 fresh fecal samples from 2 clinically healthy goats were collected at different day ages to survey goat-borne zoonotic bacterial infection, and 19 fresh fecal samples from diarrhetic goats were tested to evaluate the possible role of zoonotic pathogens in goat diarrhea. Following all samples were analyzed by Metagenomic Sequencing, a total of 20 kinds of zoonotic bacteria were screened from healthy goats, and 11 (55%) of them were infection mainly during the preweaned period. Of the 19 fresh fecal samples from diarrhetic goats, all were confirmed to be zoonotic bacterial infection positive (range from 11 to 12 species). After comparison with healthy samples of the same or similar day-age goats, it was found that Lactococcus garvieae, Helicobacter pylori, Klebsiella pneumoniae, Shigella sonnei, Shigella boydii, Campylobacter coli, Salmonella enterica, Acinetobacter baumannii, Shigella flexneri, Shigella dysenteriae and Clostridium perfringens and Campylobacter fetus were highly increased incases in some diarrheic cases, while the remains had no significant change. The results suggest that goats may act as a reservoir for many zoonotic bacteria, and some of them may be associated with goat intestinal inflammation.

Isolation, Identification and Evaluation of Antibiotic Sensitivity and Resistance of Shigella Dysenteriae Isolated from Food, Water and Soil

Background: Shigella is a genus of gram negative, facultative anerobic rod shaped bacteria divided into four species that are Shigella dysenteriae (serogroup A), Shigella flexneri (serogroup B), Shigella boydii (serogroup C) and Shigella sonnei (serogroup D). Shigella species are the etiological agent of shigellosis and most serious illnesses are caused by Shigella dysenteriae. Aim: The aim of this study was to determine antibiotic sensitivity and resistance of Shigella dysenteriae isolates to ensure that severe diarrhea infection remain treatable. Method: A total of 75 samples from different environmental sources were collected, processed and tested for the identification of Shigella dysenteriae after observing the cultural, morphological and biochemical characteristics. Antibiotic sensitivity and resistance pattern of these isolates were also studied by disk diffusion method. Results: It was observed that out of 75 samples, 42 samples were positive for Shigella dysenteriae. All Shigella isolates were highly resistant to Penicillin (100%), Vancomycin (100%), Aztreonam (100%), Ertapenem (100%) followed by Ceftriaxone (78%) and aAmikacin (74%) whereas highly sensitive to Imipenem (72%) followed by Ciproflaxin (67%) and Meropenem (47%). Conclusion: Resistance of Shigella dysenteriae to antibiotics that are commonly used for treatment of shigellosis is increasing at alarming rate. Multipronged strategies should be adopted to ensure that severe diarrhea infection remain treatable.

Antibacterial, antifungal and in vivo anticancer activities of chitin-binding lectins from Tomato (Solanum lycopersicum) fruits

A mixture of chitin-binding lectins from Tomato ( Solanum lycopersicum ) fruits, designated as Tomato chitin-binding lectins (TCLs), was isolated through affinity chromatography using an acetylated chitin column. Molecular weights of TCLs were determined to be 30 to 115 KDa which possessed mild toxicity with an LC 50 value of 521 µg/ml examined by the brine shrimp nauplii toxicity assay. Strong antibacterial activity of TCLs was found against Escherichia coli , Staphylococcus aureus and Shigella boydii at a concentration of 500 µg/ml by using disc diffusion method. Minimum inhibitory concentrations (MIC) of TCLs against Staphylococcus aureus and Escherichia coli were found to be 200 µg/ml and 140 µg/ml, respectively whereas minimum bactericidal concentrations (MBC) against the same bacterial species were 840 and 600 µg/ml, respectively. TCLs also exerted antibiofilm activity (53.32% at 250 μg/ml) against Escherichia coli . Strong antifungal activity of TCLs against Aspergillus niger was found at 600 µg/ml whereas the lectin mixture agglutinated A. niger spores at 200 µg/ml. TCLs exhibited 19.63% and 59.91% anti-proliferative activity against Ehrlich ascites carcinoma (EAC) cells in vivo in Swiss albino mice when intraperitonealy injected at doses 1.0 mg/kg/day and 2.0 mg/kg/day, respectively for five consecutive days. Morphological changes of apoptosis in EAC cells under fluorescence microscope and alteration of the expression of apoptosis-related genes (Fas, Caspase 8 and Caspase 3) had also been observed. MTT assay showed 27.61%, 38.74% and 49.23% of in vitro anticancer activity of the tomato lectins at concentrations of 37.5, 75 and 150 µg/ml, respectively.

Isolation and Characterization of Potential Lactic Acid Producing Bacteria from Fermented Fruit Juice

Lactobacillus species are used as probiotics to inhibit human pathogens because of their ability to produce antimicrobial substances. However, when different kinds of antibiotics are used, the antibiotic resistance of drug-resistant bacteria increases. In this study, lactic acid-producing bacteria with antimicrobial activity were isolated and used as probiotics to inhibit six human pathogens, namely Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus, Salmonella typhi, and Shigella boydii. Nine bacterial isolates were obtained from the crude juice of sugar cane (Saccharum officinarum), strawberry (Fragaria ananassa), and fruit pulp of palm (Borassus flabellifer). Among them, three bacterial isolates (S1, SC, and PP) produced acid and clear zones around the colonies on Glucose Yeast Extract media supplemented with calcium carbonate (GYC). These three bacterial strains were then identified on the basis of colony morphology and using different biochemical tests. 16s rRNA sequencing identified the indigenous lactic acid-producing bacteria S1 as Lactobacillus plantarum and both isolates (SC and PP) as Leuconostoc mesenteroides. L. plantarum (S1) showed the best inhibition zone (12 mm) on pathogens S. aureus, P. aeruginosa, and E. coli. Therefore, these lactic acid-producing bacteria isolated from various fermented fruit juices in Myanmar shows potential for development as probiotics.

H1 helix of colicin U causes phospholipid membrane permeation.

In light of an increasing number of antibiotic-resistant bacterial strains, it is essential to understand an action imposed by various antimicrobial agents on bacteria at the molecular level. One of the leading mechanisms of killing bacteria is related to the alteration of their plasmatic membrane. We study bio-inspired peptides originating from natural antimicrobial proteins colicins, which can disrupt membranes of bacterial cells. Namely, we focus on the α-helix H1 of colicin U, produced by bacterium Shigella boydii, and compare it with analogous peptides derived from two different colicins. To address the behavior of the peptides in biological membranes, we employ a combination of molecular simulations and experiments. We use molecular dynamics simulations to show that all three peptides are stable in model zwitterionic and negatively charged phospholipid membranes. At the molecular level, their embedment leads to the formation of membrane defects, membrane permeation for water, and, for negatively charged lipids, membrane poration. These effects are caused by the presence of polar moieties in the considered peptides. Importantly, simulations demonstrate that even monomeric H1 peptides can form toroidal pores. At the macroscopic level, we employ experimental co-sedimentation and fluorescence leakage assays. We show that the H1 peptide of colicin U incorporates into phospholipid vesicles and disrupts their membranes, causing leakage, in agreement with the molecular simulations. These insights obtained for model systems seem important for understanding the mechanisms of antimicrobial action of natural bacteriocins and for future exploration of small bio-inspired peptides able to disrupt bacterial membranes.

THE METHANOLIC EXTRACT OF MIMOSA PIGRA LEAVES REDUCES THE SEVERITY OF DIARRHEA AS WELL AS INHIBITS THE GROWTH OF DIARRHEA-CAUSING BACTERIA

Objective: Diarrhea is a major global health issue that has become increasingly prevalent in developing countries. In Bangladesh, Mimosa pigra L. is used traditionally for the treatment of diarrhea and also to control infection. Our main objective was to evaluate whether the methanolic extract of Mimosa pigra (MEMP) leaves has the antidiarrheal effect as well as the antibacterial effect against diarrhea-causing bacteria. Methods: The antibacterial potentialities of MEMP leaves were investigated by the disc diffusion method against six Gram-positive and six Gram-negative bacteria at 500 μg/disc. Kanamycin (30 μg/disc) was used as the standard drug. Antidiarrheal activities of leaf extracts were determined at two doses (200 and 400 mg/kg) in a castor oil and magnesium sulfate-induced diarrheal model in mice. The results were evaluated by One-Way Analysis of Variance (ANOVA) followed by Dunnet’s test. **P<0.01 and ***P<0.001 were considered significant compared to control. Results: The MEMP leaves exhibited moderate to potent antimicrobial activity with the zone of inhibition range 11 to 17 mm against diarrhea causing bacteria such as Salmonella paratyphi (16.33 mm), Salmonella typhi (17 mm), Shigella boydii (12 mm), Shigella dysenteriae (12.67 mm) and Escherichia coli (11 mm). Furthermore the severity of diarrhea was significantly reduced (P<0.001) by MEMP leaves at a dose of 400 mg/kg (13±2.16) compared to control (30.25±2.87) by castor oil-induced method. The same dose of the extract also significantly inhibited (P<0.01) the severity of diarrhea (14.75±1.71) compared to control (24±2.16) by magnesium sulfate-induced diarrheal model. The percent inhibition of diarrhea in 3h by MEMP leaves at a dose of 400 mg/kg was 57.02% and 38.54% in castor oil and magnesium sulfate-induced diarrheal model, respectively. Conclusion: Confirmed findings in this study naturally suggested that MEMP leaves could be an effective antibacterial and antidiarrheal formulation.

Investigating how the LPS structure affects the immune response of gram-negative bacterial outer membranes

Lipopolysaccharides (LPS) are stabilizing structures in the outer membranes of gram-negative bacteria. They serve to protect the cells from environmental stress as they are transported into and out of their host organism. This study will look at two strains of gram-negative bacteria—Escherichia coli 0188 and Shigella boydii 016—and their LPS conformations and dynamics to understand their immune responses. This will be done by creating molecular dynamics (MD) simulations of the species’ LPS with 10 repeating units of the O-antigen polysaccharide in symmetric membrane systems.

Characterization and drug susceptibility pattern of Salmonella and Shigella in children below five years: a cross-sectional study conducted in Lodwar, Turkana County, in Northern Kenya.

IntroductionSalmonella and Shigella infections are waterborne associated infections globally known to cause serious illnesses in all age groups, but can be more devastating in children below five years. Antimicrobial resistance has been known to worsen the existing challenge in the management of Salmonella and Shigella infections. The aim is to isolate and identify Salmonella and Shigella among children less than five years with diarrhea and to determine resistance to commonly prescribed drugs at the Lodwar County and Referral Hospital in Northern Kenya.Methodsusing a cross-sectional study design, a descriptive experimental study was conducted on 196 children with diarrhea using rectal swabs. A structured questionnaire was used to collect sociodemographic information. Samples were then received in the microbiology laboratory, and macroscopic and microscopic examinations were done before culture on specific selective media. Thereafter, biochemical confirmation of the growths done then confirmed results tabulated before analysis.Resultsfrom the total samples collected (196) Shigella dysenteriae cases were 4 (5%), while Shigella Flexneri were 7 (9%), Shigella sonnei were 3 (4%), Shigella boydii were 4 (5%) and Salmonella typhimurium were 2 (2.4%). From these, about 70% of the isolated Salmonella and Shigella demonstrated high antibiotic resistance to Amoxilliclav and Ampicillin, both with high minimum inhibitory concentrations (MICs) values of about 8ug/ml. While over 80% drug susceptibility was noted in Amikacin (1ug/ml), Ciprofloxacin (2ug/ml), Ceftriaxone (4ug/ml) and Ceftazidime (4ug/ml).ConclusionSalmonella and Shigella are among the common contributors of diarrhea among children less than five years. Drug resistance among the commonly used antibiotics is a serious indicator that possible misuse of antibiotics especially the beta lactam penicillin's.

Antioxidative and animal model-based pharmacological properties evaluation of leaves of Trema cannabina Lour.

Medicinal plants are of great importance since they exert beneficial pharmacological effects. In this study, phytochemical analysis of the ethanolic extract of the leaves of Trema (T.) cannabina Lour (family Cannabaceae) revealed the presence of carbohydrate, alkaloids, steroid, tannin and absence of gum, saponins, glycosides. Herein, a series of investigations were conducted with the extract to confirm the antioxidative, analgesic, antidiarrhoeal, and antimicrobial properties. T. cannabina extract showed antioxidant activity, both qualitatively and quantitatively. It displayed free radical scavenging activity in the 2,2-diphenylpicrylhydrazyl (DPPH) assay (IC50 = ≈201 µg/mL) which is comparable to that of ascorbic acid (IC50 = ≈13 µg/mL), a well-known standard antioxidant. Further, 250 and 500 mg/kg of the extract exhibited 28.95% (p=0.07) and 40.79% (p<0.02) inhibition of writhing reflex, respectively compared to the standard drug diclofenac (25 mg/kg, inhibition of writhing reflex 69.74%) in mice. In addition, we found significantly reduced number of stools with the extract at these doses (p<0.001) compared to the standard drug loperamide (3 mg/kg, p<0.001) in the castor oil-induced diarrhoeal mice. Interestingly, the extract (500µg/disc) suggested credible antibacterial properties against the bacterial strains; Enterococcus faecalis, Streptococcus pyogenes, Shigella dysenteriae, Vibrio cholera and no activity against Escherichia coli, Shigella boydii, Staphylococcus aureus, Staphylococcus epidermidis and Proteus mirabilis. For the comparison of antimicrobial properties, standard antibiotic discs of Kanamycin were used. Collectively, the obtained results provide compelling evidence for the role of T. cannabina in exerting antioxidant, analagesic, antidiarrhoeal, and antimicrobial effects, which rationale the use of this plant in traditional medicine. However, further investigations are required to confirm these effects at molecular level.

A Lateral Flow Immunoassay Strip with Aggregation-Induced Emission Tcbpe for Multiple Detection of Shigella Boydii, Salmonella Typhimurium, and Escherichia Coli O157:H7

A Lateral Flow Immunoassay Strip with Aggregation-Induced Emission Tcbpe for Multiple Detection of Shigella Boydii, Salmonella Typhimurium, and Escherichia Coli O157:H7

Shigellosis and Development of Multiple Antimicrobial Resistance Mechanisms of Shigella spp.

Shigellosis is a serious public health issue. Millions of people suffer from this deadly food and water borne disease each year. The main manifestations of affected persons are bloody diarrhea with excessive dehydration. The causative agent of this disease is the bacteria Shigella spp. which has four serogroups. Though Shigella flexneri and Shigella dysenteriae are the dominant serogroups in developing countries, reports of other serogroups, namely Shigella boydii and Shigella sonnei, in the food contaminations are available. There are seasonal variations of Shigella infection throughout the world. In Asian subcontinent, monsoon and post monsoon times are the ideal for infection. The transmission of the bacteria in human is usually caused by feco-oral route or by contaminated food and water. There are several groups of antibiotics like foscomycin, macrolide, amiglycoside, tetracycline etc. which were used before. But they are now become useless as Shigella spp. is getting resistant against those drugs. The quinolone groups of antibiotics like ciprofloxacin, ofloxacin, norflxacin, ceftriaxone etc. are the important drugs for the cure of the disease shigellosis but prevalence of drug resistant strains of Shigella spp. against those drugs are a great concern nowadays. The occurrence of plasmid mediated quinolone resistance genes (PMQR), efflux pump proteins and effective mutations at drug binding region of gyrA etc. are the major mechanisms for the development of drug resistance.

Investigation of Azithromycin Minimum Inhibitory Concentration Values and Carbapenem Resistance in Salmonella and Shigella Clinical Isolates

Increasing resistance to first-line antibiotics used in the treatment of infections caused by Salmonella and Shigella species is emerging. Azithromycin presents a good alternative treatment option for Salmonella and Shigella infections. However, there are limited data regarding the susceptibility of azithromycin in Turkey. In this study, we aimed to evaluate the susceptibility of Salmonella and Shigella species to azithromycin, to determine and compare the minimum inhibitory concentration (MIC) values and disk diffusion zone diameters. In addition, susceptibility to meropenem and first-line antibiotic options in isolates was also investigated. A total of 170 Salmonella, 76 Shigella clinical isolates collected between 2014 and 2018 in our hospital were tested for their susceptibility to azithromycin, meropenem, ampicillin, pefloxacin, trimetoprim-sulfamethoxazole, ceftazidime, and cefotaxime. Isolates were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry. The isolates were confirmed and serotyped by the reference laboratory using the conventional slide agglutination method. Susceptibility of the isolates to azithromycin and other antibiotics was evaluated by Kirby-Bauer disk diffusion method. MIC values of azithromycin were determined by the reference broth microdilution method. Combined disk diffusion test was used for the detection of extended spectrum beta-lactamase (ESBL) production. Polymerase chain reaction was performed for macrolide and carbapenem resistance genes and the detected resistance genes were confirmed by sequencing. Of the 76 Shigella isolates tested, 64 (84.2%) were identified as Shigella sonnei, 10 (13.2%) as Shigella flexneri, one (1.3%) as Shigella boydii, and one (1.3%) as Shigella dysenteriae. Among the 170 Salmonella isolates, 131 (77%) were identified as Salmonella enteritidis, 11(6.5%) as Salmonella Typhimurium, 8 (4.7%) as Salmonella Kentucky, 5 (2.9%) as Salmonella Paratyphi B, 4 (2.4%) as Salmonella Infantis, 3 (1.8%) as Salmonella Cholerasuis, and 8 (4.7%) as other serovars (Salmonella Agona, Salmonella Dabou, Salmonella Gallinarum, Salmonella Hadar, Salmonella Muenchen, Salmonella Newport, Salmonella Paratyphi C, Salmonella Senftenberg), respectively. ESBL production was determined as 7.9% (6/76) in Shigella isolates and 2.9% (5/170) in Salmonella isolates. A carbapenem resistant S.Senftenberg isolate positive for the blaOXA-48 resistance gene was detected in our study. Meropenem MIC value of the isolate was detected as > 32 µg/ml with gradient diffusion test. Among all isolates, only one S.boydii isolate was detected as resistant to azithromycin with a MIC value of 128 µg/ml. The isolate was positive for the existence of mphA gene by PCR. In the disk diffusion test, azithromycin inhibition zone diameters were ≥ 12 mm in all of the tested isolates, except for the azithromycin-resistant isolate, and the azithromycin MICs were determined as ≤ 16 µg/ ml by broth microdilution. Increasing resistance to commonly used antibiotics in Salmonella and Shigella species is emerging. The detection of a carbapenem-resistant Salmonella isolate in our study indicates that the spread of carbapenem resistance to other Enterobacterales species may cause global problems. Antimicrobial susceptibility testing of azithromycin for Salmonella and Shigella species has been difficult to establish due to the lack of approval in vitro breakpoints for all species. Consequently, our data shows that azithromycin exhibits as a good alternative therapeutic choice for the treatment of gastrointestinal diseases caused by Salmonella and Shigella species. Further studies are needed to provide appropriate in vitro breakpoints supported by clinical data.

Effect of the Histone Methyltransferase Specific Probe BRD4770 on Metabolic Profiling of the Endophytic Fungus Diaporthe longicolla.

The endophytic fungus Diaporthe longicolla was isolated from the stem of Saraca asoca (Roxb.) Willd., commonly known as Ashok plant in India and Sri Lanka. Since no reports are available regarding epigenetic modulations by BRD4770 in microbial entities, D. longicolla was treated with different concentrations of BRD4770 for this purpose and evaluated for its antioxidant and antibacterial potential against five human pathogenic bacteria, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Shigella boydii, Klebsiella pneumoniae, and Escherichia coli. The crude extract obtained from cultures treated with 100 nM concentration of BRD4770 showed increased antioxidant activity and inhibition zone against S. aureus and MRSA, compared to the non-treated control. The composition of the non-treated and treated crude extract was analyzed, and induced compounds were identified with the help of Gas chromatography–mass spectrometry (GC-MS) and LC-ESI-MS/MS. LC-ESI-MS/MS analysis showed that berberine (antibacterial)-, caffeine-, and theobromine (antioxidant)-like compounds were induced in the BRD4770-treated crude extract. The presence of particular absorbance at a wavelength of 346.5 nm for berberine, 259.4 nm for caffeine, and 278.4 nm for theobromine in the reverse-phase high-performance liquid chromatography (HPLC) analysis of both BRD4770-treated crude metabolites and standard solution of the above compounds strongly supported the increased antibacterial and antioxidant activities that may be due to inducing the alterations in bioactivities of the BRD4770-treated culture.

Antidiarrheal activity of aqueous extract of leaves of Euphorbia hirta L.

Context: Euphorbia hirta L. is widely distributed in the Indian subcontinent and has many ethnomedicinal uses. Traditionally, the leaves of E. hirta have been used as antidiarrheal agents, for bronchial and respiratory diseases and against conjunctivitis. Aims: To evaluate the antidiarrheal activity of the aqueous extract of leaves of Euphorbia hirta. Methods: Steam and aqueous extracts of leaves of E. hirta were evaluated for their antidiarrheal activity by in vitro antiprotozoal and antimicrobial activity testing, in vivo evaluation of % protection against diarrhea in castor-oil induced rat diarrhea model, gastrointestinal transit and enteropooling assays in rat model and ex vivo tissue contractility studies. Results: Steam and aqueous extracts of leaves of E. hirta demonstrated antiprotozoal activity against Entamoeba histolytica and Giardia lamblia with MICs ranging from 31.25-62.5 µg/mL to 125-250 µg/mL. Both the extracts showed antibacterial activity against Salmonella abony, Escherichia coli and Shigella boydii. In vivo antidiarrheal activity evaluation in castor-oil induced diarrhea model in rats revealed that the steam extract at a dose of 1621 mg/kg body weight (b.w.) produced % inhibition in defecation comparable to loperamide (4 mg/kg b.w.). Aqueous extract produced significant reduction in fecal output when compared to the untreated control group (p<0.05). However, the extracts failed to have any significant effect on the gastrointestinal transit of charcoal meal in rats. Also, gastric fluid accumulation was significantly reduced by steam extract at 2162 mg/kg b.w. and aqueous extract at 100 mg/kg b.w. (p<0.05) when compared to the untreated group. The smooth muscle relaxation produced by the steam extract on the isolated rat ileum was comparable to that produced by atropine (0.05-0.4 µg/mL). Conclusions: The results of this study provide support for the traditional use of Euphorbia hirta leaves as an antidiarrheal agent.

Anti-Bacterial, Anti-Diarrheal, and Cytotoxic Activities of Edible Fruits in the Sundarbans Mangrove Forest of Bangladesh.

This study evaluated anti-bacterial, anti-diarrheal, and cytotoxic activities of ten edible fruits (Aegiceras corniculatum, Avicennia officinalis, Bruguiera gymnorrhiza, Ceriops decandra, Heritiera fomes, Nypa fruticans, Phoenix paludosa, Sarcolobus globosus, Sonneratia caseolaris, and Xylocarpus mekongensis) in the Sundarbans mangrove forest of Bangladesh. Highest antibacterial activity was shown for ethanol:methanol (1:1) extracts of S. caseolaris (2 mg/disc), which demonstrated inhibition zones of 16.7, 17.0, 14.7, 15.7, and 15.7 mm against Escherichia coli, Klebsiella sp., Shigella boydii, Shigella sonnei, and Staphylococcus aureus, respectively. In mice with castor oil-induced diarrhea, S. caseolaris extract (250 mg/kg body weight) showed the highest inhibition (87.7%) and delayed the onset time (273 min) of diarrheal episodes, followed by A. corniculatum extract (inhibition, 83.6%; delayed onset time, 187.4 min). S. caseolaris and A. corniculatum fruit powders were successively fractionated into n-hexane, diethyl ether, chloroform, ethanol, and methanol. Antidiarrheal activity significantly increased with increasing polarity of these fractions. In brine shrimp lethality assay, S. globosus extract demonstrated the highest cytotoxicity (59.2 μg/mL), followed by H. fomes (74.1 μg/mL) and C. decandra (116.7 μg/mL); however, lowest cytotoxicity was shown for A. corniculatum, A. officinalis, and S. caseolaris extracts. Mice treated with A. corniculatum extract did not experience any acute toxicity. These results demonstrate that S. caseolaris and A. corniculatum fruits have potential to treat diarrhea and may act as useful nutraceuticals.

Bioactive potential of Aphanamixis polystachya seed extracts

Aphanamixis polystachy seed extracts were examined for their in-vitro biological activities. The n-hexane and methanol extract showed significant phenolic content of 12.0 and 11.7 mg GAE/g, respectively. Antioxidant activity was exhibited by the methanol extract (IC50: 22.34 μg/mL) and moderate activity was shown by the n-hexane extract (IC50: 63.05 μg/ml) compared to BHT (tert-butyl-1- hydroxy toluene, IC50: 14.01 μg/ml) though both extracts caused moderate clot lysis of 18.84% and 23.49% compared to the positive control Streptokinase (65.16%). The n-hexane and methanol extract had shown 18.2% and 32.2% inhibition of hypnotic solution induced haemolysis respectively, while the n-hexane extract had almost no activity (2.21%) and methanol extract showed very high (70.17%) inhibition of heat induced haemolysis compared to acetyl salicylic acid (71.9%). Sensible and substantial cytotoxicity was exhibited by the n-hexane (LC50:13.45 μg/ml) and methanol extracts (LC50:1.61 μg/ml), respectively compared to vincristine sulfate (LC50: 0.45 μg/ml). The n-hexane extract showed no antimicrobial activity against the tested micro-organisms but the methanol extract showed a strong zone of inhibition (25 mm) against Staphylococcus aureus and a moderate zone of inhibition (10mm) against Shigella boydii. Both the extracts exhibited almost zero haemolysis.
 Bangladesh J. Sci. Ind. Res.56(2), 75-86, 2021

Antimicrobial resistance in Shigella species: Our five years (2015–2019) experience in a tertiary care center in north India

PurposeShigella is the second leading cause of diarrhoeal mortality especially in children <5 years of age in African and Asian countries. Rapid changes are occurring in the epidemiology of shigellosis and Shigella are increasingly becoming highly drug resistant. To determine the serogroup distribution and antimicrobial resistance of Shigella isolated at our tertiary care centre in North India. MethodsA retrospective study was conducted where demographic details along with antimicrobial susceptibility data of Shigella isolated from stool specimens from 1st January 2015 till 31st December 2019 were retrieved from records and analyzed by WHONET 2019 software. ResultsShigella species was isolated in 1.31% (n = 137) of a total of 10,456 stool samples. Males predominated (n = 82; 59.8%) and majority of cases were admitted (n = 94; 68.6%). Children ≤5 years of age (n = 47; 34.3%) were the most commonly affected. Adults in the 21–40 age group contributed 27% of cases (n = 37). Overall, Shigella flexneri (n = 87; 63.5%) was the most common serogroup followed by non-agglutinable Shigella (n = 28; 20.4%) while Shigella sonnei (n = 12, 8.8%) and Shigella boydii (n = 9, 6.6%) fluctuated over the years. Shigella dysenteriae reappeared in 2019 after a hiatus of ten years. Overall, 45.3% (n = 62) of isolates were multidrug resistant to CLSI recommended drugs and high resistance was noted for ampicillin/amoxicillin (68.1%), cotrimoxazole (75.8%) ciprofloxacin (61.5%) and ceftriaxone/cefotaxime (45.2%). ConclusionsShigella have become highly drug resistant to fluoroquinolones and cephalosporins. Community based studies are required to truly assess the burden of AMR in India.

Phytochemical Screening and Antibacterial Activity of Pistacia atlantica and Pinus canariensis Extracts

The detection qualitative of Phytochemical compounds of extracts was carried out using color reagents, total content of phenols and flavonoids was specified using folin– ciocalteu and aluminium chloride method, respectively, and antioxidant activity was determined through its ability to free radicals scavenging using DPPH radical. The efficacy of the plant extracts against pathogenic bacteria was studied by agar well diffusion method with different concentrations, and microdilution method was used to measure minimum inhibitory concentration (MIC) of all plant extracts. The results showed presence of tannins, phenols, and flavonoids in all extracts of both plants, while saponins were found in aqueous extracts only, cardiac glycosides and coumarins were absent in all plant extracts. Ethanolic extract of Pistacia atlantica recorded the highest content of phenols and flavonoids as 263.76 ± 0.53 (mg GAE/g Dw) and 46.83 ± 0.55 (mg RE/g Dw), respectively. While aqueous extract of Pinus canariensis recorded the lowest content of of phenols and flavonoids 30.11 ± 0.37 (mg GAE/g Dw) and 5.43 ± 0.38 (mg RE/g Dw), respectively. Both plants have been shown to have good antioxidant activity, as ethanolic extract of P. atlantica recorded the best ability to free radicals scavenging 90.27% ±1.51, ethanolic extracts of both plants were the most effective in inhibiting bacteria especially at high concentrations (500 mg/mL); the inhibition zone diameter of P. atlantica extract was reached against Shigella boydii 33.56 mm, while aqueous extract of P. canariensis was the most effective against Pseudomonas aeruginosa; the inhibition zone diameter was 21 mm. MIC ranged between 5.468 and 43.75 mg/mL depending on plant extract and bacterial species. This confirms the importance of plant extracts as a natural source of antibacterial to confront problems of increasing bacterial resistance to antibiotics that threaten public health.