Monitoring in vitro antibacterial efficacy of Terminalia alata Heyne ex. Roth, against MDR enteropathogenic bacteria isolated from clinical samples

Evaluation of the antimicrobial attribute of bioactive peptides derived from colostrum whey fermented by Lactobacillus against diarrheagenic E. coli strains

Colostrum known as "liquid gold" contains approximately 60-80% of whey proteins that can be a great source of bioactive peptide production. Therefore, this study aimed to perform a comparative antimicrobial evaluation of the bioactive peptide generated from L. rhamnosus C25, L. rhamnosus C6, and L. casei NCDC17 fermented colostrum whey. Peptide fractions 10 kDa, 5 kDa, and 3 kDa were isolated using their respective molecular weight cut-off membranes and antimicrobial activity was evaluated against diarrheagenic E. coli strains. The higher inhibition was shown by < 10 kDa peptide fractions from L. rhamnosus C25 fermented colostrum whey and the zone of inhibition was 15 ± 0.06 (E. coli MTCC 723), 17 ± 0.04 (E. coli MTCC 724), 18 ± 0.05 (E. coli MTCC 725), and 17 ± 0.02 (E. coli ATCC 25922). In addition, ST-1 and LT-1 genes of E. coli strains were also confirmed using PCR which is responsible for the diarrheagenic property. Further, the interaction of potent peptides against E. coli strains was also observed by scanning electron microscope. Hence, the significance of the present study emphasized that these bioactive peptides generated from fermented colostrum whey can be used as ingredients in functional food against diarrhoea.

Estimation of Trace Elements, Antioxidants, and Antibacterial Agents of Regularly Consumed Indian Medicinal Plants

Nutritional profile of minerals and antioxidants in Indian spice extracts was evaluated in order to examine their efficacy in treating various diseases, disorders, and allergies in human health. Extracts of four medicinal plants such as Curcuma longa, Zingiber officinale, Piper nigrum, and Piper longum, regularly consumed as spice products in South Asia, have been studied using elemental analysis, antioxidant, and antibacterial studies. While potassium (K) and calcium (Ca) were estimated to be the major elements, trace elements such as manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), and lead (Pb) were determined in the plant extracts. Although higher concentration of Cu was estimated in Piper nigrum extracts, it can be inferred that Cu is not the only factor that is responsible for gastrointestinal disorders. Methanolic extract of the plants showed the highest inhibition zone for Curcuma longa against maximum bacterial strains while Zingiber officinale showed inhibition against S. aureus, K. pneumonia, and P. aeruginosa. Because of the highest concentration of antioxidants and inhibitory action against most of the bacterial strains, Curcuma longa can be used as a co-therapeutic agent in healing gastrointestinal infections.

A review on antimicrobial botanicals, phytochemicals and natural resistance modifying agents from Apocynaceae family: Possible therapeutic approaches against multidrug resistance in pathogenic microorganisms

Accelerated emergence of drug- resistant pathogenic microbes, their unbeatable virulence and a gradual loss of efficacy of currently used antimicrobial agents over the last decade, have expanded the scope of herbal medicine to combat this emerging challenge to have a wide spectrum of activity to develop effective medicines with lesser untoward side effects. Plant-based natural products should be of utmost interest to today's pharmaceutical industries since they are a primary source of new chemical entities directed at new drug targets. Apocynaceae or 'Dogbane' family has attained a global reputation as a source of some life-saving plant-derived products and novel compounds. Members of this family have also been extensively investigated against several nosocomial pathogenic microbes through in vitro and in vivo experimental settings. Several plant-derived components obtained from members of this family have also exhibited remarkable microbial growth inhibitory properties. Popular and widely accepted international databases such as PubMed, Science Direct, ResearchGate, Scopus, Google Scholar, JSTOR and more were searched using the various search strings such as Apocynaceae, antimicrobials, multidrug resistance, resistance modifying agents and pathogenic microorganisms were used in various combinations to retrieve several citations related to the topic. The current review encompasses recent developments in experimental studies and phytochemical analyses which correlates with antimicrobial efficacy of selected Apocynaceous plants along with synergistic mechanism and structural details. The present review recognizes and leverages the importance of Apocynaceae plants, which could be of significant interest in the development of more effective and less toxic antimicrobial drugs which may surmount multidrug resistance. Three different paradigm models harnessing clinical antimicrobial resistance (AMR) including the plant family Apocynaceae, Gram-positive and Gram-negative bacterial species have been broadly discussed in this review. In a nutshell, the present review represents a comprehensive account on the antimicrobials and resistance modifying agents obtained from the members of the plant family Apocynaceae and derived phytochemicals. It also gives an insight into the underlying mode of action of these phytochemicals against an array of pathogenic bacteria, their mechanism of antibiosis, plant parts from which the phytochemicals were isolated or the extracts was prepared with a critical discussion on the botanically-derived antibiotics as a template for antimicrobial drug development.

Defying Multidrug Resistance! Modulation of Related Transporters by Flavonoids and Flavonolignans

Multidrug resistance (MDR) is a major challenge for the 21th century in both cancer chemotherapy and antibiotic treatment of bacterial infections. Efflux pumps and transport proteins play an important role in MDR. Compounds displaying inhibitory activity toward these proteins are prospective for adjuvant treatment of such conditions. Natural low-cost and nontoxic flavonoids, thanks to their vast structural diversity, offer a great pool of lead structures with broad possibility of chemical derivatizations. Various flavonoids were found to reverse both antineoplastic and bacterial multidrug resistance by inhibiting Adenosine triphosphate Binding Cassette (ABC)-transporters (human P-glycoprotein, multidrug resistance-associated protein MRP-1, breast cancer resistance protein, and bacterial ABC transporters), as well as other bacterial drug efflux pumps: major facilitator superfamily (MFS), multidrug and toxic compound extrusion (MATE), small multidrug resistance (SMR) and resistance-nodulation-cell-division (RND) transporters, and glucose transporters. Flavonoids and particularly flavonolignans are therefore highly prospective compounds for defying multidrug resistance.

Antibacterial efficacy of five medicinal plants against multidrug-resistant enteropathogenic bacteria infecting under-5 hospitalized children

OBJECTIVE

To evaluate in vitro antibacterial effectiveness of five medicinal plants used by an Indian aborigine, against 8 multidrug-resistant (MDR) enteropathogenic bacteria isolated from clinical samples of under-5 hospitalized children.

METHODS

Antibiotic sensitivity patterns of eight clinically isolated strains of enteropathogenic bacteria, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Salmonella paratyphi, S. typhi, Shigella dysenteriae, S. sonnei and Vibrio cholerae were assessed by disc-diffusion method. Antibacterial activities of 8 solvent-extracts of leaves and bark of five medicinal plants were monitored by the agar-well diffusion method. The microbroth dilution method was used to assess minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Qualitative phytochemical analyses of active plant extracts were carried out.

RESULTS

Ethanol, ethyl acetate and methanol extracts of Holarrhena antidysenterica leaf tissue were most effective against 8 MDR pathogens in vitro. Similarly, acetone, ethanol and methanol extracts of Terminalia alata leaf tissue; chloroform, ethyl acetate and methanol extracts of Terminalia arjuna leaf tissue and ethyl acetate, ethanol and methanol extracts of Paederia foetida leaf tissue were most effective in inhibiting in vitro growth of the 8 MDR enteropathogens. Ethyl acetate and methanol extracts of H. antidysenterica bark tissue; acetone, ethanol and methanol extracts of T. alata bark tissue and acetone, ethanol and methanol extracts of T. arjuna bark tissue were most effective in controlling enteropathogen growth. The minimum inhibitory concentration and minimum bactericidal concentration values of the 3 most antimicrobial leaf and bark extracts from the five plants were in the range of 1.56 to 50 mg/mL.

CONCLUSION

These 5 plants exhibited in vitro control over a cohort of 8 enteropathogenic bacterial strains isolated from clinical samples.

Prevalence of two multidrug-resistant Klebsiella species in an Indian teaching hospital and adjoining community

BACKGROUND

The Gram-negative pathogenic bacteria Klebsiella oxytoca and Klebsiella pneumoniae produce the extended spectrum β-lactamase (ESBL) and cephalosporinase enzymes and are the major causes of hospital acquired (HA) infections and epidemics in non-hygienic communities in the majority of developing countries.

METHODS

The prevalence of multidrug resistance among 445 strains of K. oxytoca and K. pneumoniae isolated from clinical samples of patients with gastrointestinal infections over a period of 42 months in the hospital was recorded, along with the sensitivity patterns to 23 antibiotics, including third-generation cephalosporin and fluoroquinolone antibiotics, using the disk-diffusion method.

RESULTS

Of 175 K. oxytoca isolates, 143 were ESBL positive and 117 were fluoroquinolone resistant. Of 270 K. pneumoniae isolates, 200 were ESBL positive and 195 were independently fluoroquinolone resistant. The HA samples yielded more isolates than the community acquired (CA) samples for each species. The K. oxytoca strains were resistant to cefepime, gatifloxacin, ciprofloxacin, ceftazidime, levofloxacin and imipenem, whereas the K. pneumoniae strains were highly resistant to ampicillin, norfloxacin, ciprofloxacin, gatifloxacin, ofloxacin, amoxyclav, ceftazidime, cefepime, cefixime, piperacillin and imipenem. The ESBL-producing and fluoroquinolone-resistant K. pneumoniae strains were more prevalent than the K. oxytoca strains in the HA/CA samples. The minimum inhibitory concentration values of the third-generation cephalosporins: cefotaxime and ceftazidime and the fluoroquinolones: ciprofloxacin and levofloxacin against both species of Klebsiella confirmed the resistance in the current/coveted treatment options.

CONCLUSIONS

Patients with other bacterial infections had a relatively higher probability of infection with ESBL-producing and fluoroquinolone-resistant Klebsiella strains. The data presented here highlight the alarming state of Klebsiella infection dynamics in the hospital and adjoining communities.

Monitoring in vitro antibacterial efficacy of 26 Indian spices against multidrug resistant urinary tract infecting bacteria

BACKGROUND

To screen methanolic extracts of 26 commonly used Indian spices against nine species of uropathogenic bacteria (Enterococcus faecalis, Staphylococcus aureus, Acinetobacter baumannii, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa), isolated from clinical samples of a tertiary care hospital for antibacterial activity.

METHODS

Bacterial strains were subjected to antibiotic sensitivity testing by Kirby-Bauer's disc diffusion method. Monitoring antibacterial potentiality of spice extracts was done by the agar-well diffusion method with multidrug resistant (MDR) strains of nine uropathogens.

RESULTS

The Gram-positive (GP) bacteria E. faecalis and S. aureus were resistant to 16 of the 21 antibiotics used. Among the Gram-negative (GN) bacteria, resistant patterns were A. baumannii and E. aerogenes to 12, C. freundii to 14, E. coli to 12, K. pneumoniae to 10, P. mirabilis to 11, and P. aeruginosa to 15 antibiotics of the 18 antibiotics used. The most effective 15 spices, having at least 25-29 mm as the size of the zone of inhibition, were Allium cepa, Brassica juncea, Cinnamomum tamala, Cinnamomum zeylanicum, Coriandrum sativum, Cuminum cyminum, Curcuma longa, Mentha spicata, Murraya koenigii, Nigella sativa, Papaver somniferum, Piper nigrum, S. aromaticum, Trachyspermum ammi, and Trigonella foenum for at least one of the GP or GN MDR bacterial strains used. Moderate control capacity was registered by nine spices, Curcuma amada, Foeniculum vulgare, Illicium verum, Mentha spicata, Papaver somniferum, Syzygium aromaticum, Trachyspermum ammi, Trigonella foenum, and Zingiber officinale. However, the best two spices for controlling all the pathogens used were C. zeylanicum and C. longa, with the highest value of 29 mm as the inhibition zone size.

CONCLUSION

The most effective and unique 16 spice plants recorded for the in vitro control of MDR uropathogens could further be pursued for the development of complementary and supplementary medicine against MDR bacteria.

In Vitro antibacterial efficacy of 21 Indian timber-yielding plants against multidrug-resistant bacteria causing urinary tract infection

OBJECTIVES

To screen methanolic leaf extracts of 21 timber-yielding plants for antibacterial activity against nine species of uropathogenic bacteria isolated from clinical samples of a hospital (Enterococcus faecalis, Staphylococcus aureus, Acinetobacter baumannii, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa).

METHODS

Bacterial strains were subjected to antibiotic sensitivity tests by the Kirby-Bauer's disc diffusion method. The antibacterial potentiality of leaf extracts was monitored by the agar-well diffusion method with multidrug-resistant (MDR) strains of nine uropathogens.

RESULTS

Two Gram-positive isolates, E. faecalis and S. aureus, were resistant to 14 of the 18 antibiotics used. Gram-negative isolates A. baumannii, C. freundii, E. aerogenes, E. coli, K. pneumoniae, P. mirabilis, and P. aeruginosa were resistant to 10, 12, 9, 11, 11, 10, and 11 antibiotics, respectively, of the 14 antibiotics used. Methanolic leaf extracts of Anogeissus acuminata had the maximum zone of inhibition size-29 mm against S. aureus and 28 mm against E. faecalis and P. aeruginosa. Cassia tora had 29 mm as the zone of inhibition size for E. faecalis, E. aerogenes, and P. aeruginosa. Based on the minimum inhibitory concentration and minimum bactericidal concentration values, the most effective 10 plants against uropathogens could be arranged in decreasing order as follows: C. tora > A. acuminata > Schleichera oleosa > Pterocarpus santalinus > Eugenia jambolana > Bridelia retusa > Mimusops elengi > Stereospermum kunthianum > Tectona grandis > Anthocephalus cadamba. The following eight plants had moderate control capacity: Artocarpus heterophyllus, Azadirachta indica, Dalbergia latifolia, Eucalyptus citriodora, Gmelina arborea, Pongamia pinnata, Pterocarpus marsupium, and Shorea robusta. E. coli, followed by A. baumannii, C. freundii, E. aerogenes, P. mirabilis, and P. aeruginosa were controlled by higher amounts/levels of leaf extracts. Phytochemicals of all plants were qualitatively estimated.

CONCLUSIONS

A majority of timber-yielding plants studied had in vitro control capacity against MDR uropathogenic bacteria.