<div>Background: Mycoplasma bovis (Gram-positive bacteria) belongs the class Mollicutes&nbsp;and to the family Mycoplasmataceae (<a href="#maunsell_2009">Maunsell and Donovan, 2009)</a>. It is a cell wall-less bacterium and are instead enveloped by a complex plasma membrane. In cattle, M. bovis is widely known causes various diseases, such respiratory disease, mastitis, arthritis and otitis. 
 
Methods: The present study was aimed to determine the antimicrobial susceptibility and identify the genes for antimicrobial resistance of Mycoplasma bovis PG45, Staphylococcus aureus and Escherichia coli. M. bovis PG45, S. aureus and E.coli were subjected to test for their sensitivity to various clinically important antibiotics (Cefotaxime, Cefuroxime, Cefaclor Cefalexin, Ofloxacin, Norfloxacin, Nalidixic acid, Amikacin, Ampicillin, Oxacilin, Amoxyclav, Rifampicin, Penicillin G and Tylosin). The minimal inhibitory concentration (MIC) of each antimicrobial agent was determined by applying an agar dilution method. Polymerase Chain reaction (PCR) was used to amplify specific DNA fragments and thus to determine the presence or absence of a target gene (VspA, tet k and tetA).&nbsp; 
 
Result: Showed the MIC values and the presence of VspA, tetK and tetA in M. bovis PG45, S. aureus and E. coli respectively.</div>

<div>Antimicrobial Susceptibility and Detection of Genes for Antimicrobial Resistance of Mycoplasma bovis, Staphylococcus aureus and Escherichia coli</div>

<div style="text-align: justify;">Mammalian defensin is the one of the important antimicrobial peptides expressed by different epithelial lining of the living organisms. Present study was undertaken to characterize the lingual antimicrobial peptide (LAP) gene of Assam local cattle (Bos indicus ) for insilco designing &nbsp;of peptide for synthesis of novel antimicrobial agents. RNA was isolated from the tongue epithelial of Bos indicus and reverse transcribed with specific primer. The amplified PCR product was purified, cloned and sequenced. The size of the PCR product was 230 bp and cloned cDNA after sequencing revealed the open reading frame (ORF) of 195 bases. The total number of predicted amino acid in the peptide was 64. Aligned amino acid sequences of Bos indicus LAP showed six conserved cysteine residues at different positions. The mature peptide of local cattle LAP had six (6) arginine, three (3) lysine, three (3) proline and one (1) histidin residues. Support vector machine algorithms showed the antimicrobial potency of different segments of the mature peptide and out of them four different most potent peptides were designed. &nbsp;From the present study, it can be concluded that the mature domain of the Bos indicus lingual antimicrobial peptide (LAP) may be use as template for synthesis of new antimicrobial agents.</div>

<div style="text-align:justify">Molecular characterization of lingual antimicrobial peptide gene of local cattle&nbsp;(Bos indicus) of Assam and insilco designing of antimicrobial peptides</div>

<div style="text-align: justify;">Pesticide resistance and environment threat due to injudicious use of chemical pesticides for disease management employs the alteration in management practices. Chitosan, a deacetylated chitin derivative, behaves like a general elicitor, inducing a non-host resistance, and prime the plants for systemic acquired resistance in addition to this Chitosan has high antimicrobial activity against a wide &nbsp;range of pathogenic and spoilage microorganisms, including fungi and bacteria. The use of chitosan in agriculture and in food systems should be based on sufficient knowledge of the complex mechanisms of its elicitor and antimicrobial mode of action. In this article we a number of studies on the investigation of chitosan antimicrobial and resistance inducing properties and application of them in agriculture sector have been summarized.</div>

<div>Chitosan: An elicitor and antimicrobial Bio-resource in plant protection</div>

<div>Bovine mastitis is one of the common diseases resulting in high economic losses in the dairy industry. Streptococcus uberis, the environmental or contagious pathogen, is one of the most frequently identified bacteria causing clinical and subclinical mastitis. Antimicrobials are commonly used to control bacterial infections in dairy cattle. The emergence of antimicrobial resistance (AMR) bacteria made the treatment of this disease by antimicrobials a challenge. Currently, AMR is a global threat to both human and animal health. This review summarizes the AMR profiles of S. uberis collected worldwide between the years 2000-2020. Most of the studies included in this review were from Europe, Estonia, Canada, Danish, Switzerland and Czech. In general, S. uberis is highly susceptible to &beta;-lactam antimicrobials, whereas resistance to tetracyclines, macrolides, aminoglycosides antimicrobials occurred in most countries. The isolates against most antimicrobials presented an increasing pattern over time. It highlights that monitoring the AMR of S. uberis is crucial to reduce the public health crisis.</div>

Antimicrobial Resistance of Streptococcus uberis Isolated from Bovine Mastitis: A Review

<div style="text-align:justify">Sodium caseinate fermented of Lactobacilli were studied for their antimicrobial activity. Out of the total 34 standard NCDC, 12 Lactobacillus cultures were selected on the basis of maximum proteolytic activity. Proteolytic property was used to study their antimicrobial activity against pathogenic and contaminating organism. This Lactobacillus was assessed for probiotic attributes. Proteolytic and probiotic strains are selected for studying antimicrobial activity using caseinate fermented. Cell free supernatant of Lactobacillus was tested for antimicrobial activity. Sodium caseinate (2.5 %) was prepared for fermentation; concentrated 10 fold at 60&deg;C was tested for antimicrobial activity against gram positive and gram negative bacteria, yeast and mold cultures. Lb. fermentum 141 had maximum antimicrobial activity as compared to other Lactobacillus and selected for further studies. Minimum inhibitory concentration of Lb 141 fermentate (MIC) against bacterial cultures was 100 &micro;g / ml whereas 120 and 150 &micro;g / ml for mold and yeast respectively. Sodium caseinate fermentate of Lb 141 showed bactericidal and fungicidal activity against a broad spectrum of microorganisms. Antimicrobial fermentate of Lb 141 may act as a natural preservative in milk food products against undesirable bacteria as well as yeast and molds.</div>

<div style="text-align: justify;">Antimicrobial activity of casein fermentate of probiotic Lactobacillus spp.</div>

<div>Background: Misuse of antibiotics has led to bacterial antibiotic resistance and antibiotic residues in meat and egg. The aim of this study was to assess the effect of dietary supplementation of chicken intestinal-derived antimicrobial peptide as an alternative to antibiotic growth promoters on the immune response of birds.&nbsp; 
 
Methods: Immune organs of randomly selected birds were collected for immune organ index. Blood samples were collected for serum to measure the antibody titre against infectious bursal disease and Newcastle disease virus using ELISA. Whole blood was collected to study the cytokine gene expression (IL-17A, IFN-&alpha;, IFN-&gamma;, TGF-&beta;, IL-10) using Real-time PCR. 
 
Result: Antimicrobial peptide supplementation had no significant effect (P&gt;0.05) on the immune organ index and serum antibody Titre against infectious bursal disease and Newcastle disease virus on the 21st and 35th days of the study. However, it significantly (P&lt;0.01) downregulated the gene expression of pro-inflammatory cytokines viz., IL-17A, IFN-&alpha;, IFN-&gamma; and upregulated IL-10 expression in peripheral blood mononuclear cells. The results suggest that supplementation of antimicrobial peptide at a level of 100 mg/kg diet improved the cell-mediated immune response in broiler chicks but would not have been sufficient to enhance the humoral immune response and immune organ index in chicks.</div>

Effects of Antimicrobial Peptide Supplementation on Immune Response and Immune Organ Index in Broiler Chicks

<div>Background: Mitigation process to curb the ever increasing problem of antimicrobial resistance through development of new class of antimicrobials is slow and costly affairs. Research on alternative to conventional antimicrobials using plant based products as good source of numerous phytochemicals have potential to cope up the antimicrobial resistance. The present study was formulated on detection of in vitro antimicrobial and antibiofilm properties of methanol leaf extract of Citrus maxima against clinical isolates of Staphylococcus aureus. 
 
Methods: Leaves of Citrus maxima plants were collected from the campus of College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Aizawl, Mizoram and processed for preparation of methanol crude extract. The plant extracts were evaluated for their phytochemical and antioxidant properties using DPPH (2, 2-Diphenyl-1-picrylhydrazyl) method. Twenty well characterized biofilm producing and multidrug resistant Staphylococcus aureus strains recovered from milk of mastitic cows from Mizoram were received from the cultural repository of the department. The plant extracts were subjected to determine their antimicrobial and antibiofilm activities against all the bacterial isolates including&nbsp;S. aureus (ATCC 29213) by in vitro agar well diffusion method and 96 well microtiter plate methods, respectively. The MIC value of the plant extracts were determined by microdilution method. 
 
Result: In the methanol leaf extract of C. maxima alkaloids, glycosides, terpenoids, tannin and phenol and flavonoids were detected by qualitative analysis. Saponin, protein, free amino acids, steroids and carbohydrates were not detected. The free radical scavenging potential of the extract was found to be 10.66&plusmn;1.84% to 36.10&plusmn;1.98%, which was comparatively lower than ascorbic acid (83.39&plusmn;0.13% to 89.76&plusmn;0.24%). A total of 8 (40.0%), 5 (25.0%) and 7 (35.0%) strains were recorded as weak, moderate and strong biofilm producer. Maximum antibacterial activity against standard culture was observed with the zone of inhibition of 18 mm at 200 mg/mL concentration and MIC value at 25 mg/mL. Maximum antimicrobial activities against clinical isolates were recorded with 11.8&plusmn;1.13 mm zone of inhibition at 200 mg/mL and MIC value at 25 mg/mL. The clinical isolates exhibited highest (85.94&plusmn;1.00%) biofilm inhibition at 6.25 mg/mL. To the best of our knowledge, this is the first-ever report on antibiofilm and antioxidative activities of C. maxima leaf extracts against any bacteria.</div>

Antimicrobial and Antibiofilm Activities of Methanol Leaf Extract of Citrus maxima against Clinical Isolates of Multidrug Resistant Staphylococcus aureus

<div>Background: Development and persistence of multidrug resistant (MDR) bacteria is considered to be one of the biggest threats to public health worldwide. Development of new antimicrobial agents and alternatives to the conventional antimicrobial agents to control the menace of AMR is the need of the hour. Plants based products can be effectively explored as potential antimicrobial, antibiofilm and antiquorum sensing agents against major bacterial pathogens of human and animals. This present study was conducted to explore the antimicrobial, antibiofilm and antiquorum sensing activity of aqueous and methanol extracts of leaf, flower, fruit and stem of Melastoma malabathricum against clinical isolates of Staphylococcus aureus and Escherichia coli. 
 
Methods: E. coli and S. aureus were isolated and identified from diarrhoeic pigs and poultry and mastitic milk of cattle of Mizoram, respectively. Leaf, flower, fruit and stem of M. malabathricum were collected from Mizoram and extracted by methanol and aqueous solvents. The antimicrobial activity and MIC was determined by using well diffusion method and 96 wells microtiter plate method, respectively. Antibiofilm activity of plant extracts was determined in 96 well tissue culture plate. Antiquorum sensing activity was determined by disc diffusion method. 
 
Result: Methanol leaf extract exhibited antimicrobial activity against E. coli but not against S. aureus with 18 mm and 6 mm zone of inhibition at 200 mg/mL and 12.5 mg/mL, respectively. Methanol flower extract showed antimicrobial activity against S. aureus but not against E. coli with 14 mm and 6 mm zone of inhibitions at 200 mg/ml and 12.5 mg/mL, respectively. Similarly, the aqueous leaf extract showed antimicrobial activity against S. aureus but not against E. coli with 12 mm and 6 mm zone of inhibition at 200 mg/mL and 100 mg/mL, respectively. The MIC of M. malabathricum methanol leaf extract against E. coli was 3.125 mg/mL, whereas the MIC value of methanol flower and leaf extracts was 6.25 mg/mL against S. aureus. Antibiofilm activity of M. malabathricum methanol leaf, methanol flower and aqueous leaf extracts was recorded only against S. aureus isolates with maximum inhibition at 0.05 mg/mL concentration. Good antiquorum sensing activities was exhibited by the M. malabathricum methanol leaf, methanol flower and aqueous leaf extracts against S. aureus isolates at 200 mg/mL concentration.</div>

<div>In vitro Antimicrobial, Antibiofilm and Antiquorum Sensing Activity of Indian Rhododendron (Melastoma malabathricum) against Clinical Isolates of Escherichia coli and Staphylococcus aureus</div>

<div>Background: Management of ever growing multidrug resistant (MDR) bacteria becomes one of the biggest threats to public health worldwide. The situation is worsening due to lack of new generation antimicrobials in the arsenal of the clinicians. Development of new alternatives to the conventional antimicrobial agents is the need of the hour to control the menace of AMR. Plants based products are attractive alternatives with proven efficacy but needs scientific investigation to explore their potential antimicrobial, antibiofilm and antiquorum sensing activities against major bacterial pathogens of human and animals. The present study was conducted to explore the antimicrobial, antibiofilm and antiquorum sensing activity of aqueous and methanol extracts of leaf, flower, fruit and stem of the Himalayan yellow raspberry (Rubus ellipticus) against clinical isolates of Staphylococcus aureus and Escherichia coli. 
 
Methods: E. coli and S. aureus were isolated and identified from diarrhoeic pigs and poultry and mastitic milk of cattle of Mizoram, respectively. Leaf, flower, fruit and stem/bark of R. ellipticus were collected from Mizoram and extracted by methanol and aqueous solvents. The antimicrobial activity and MIC was determined by well diffusion method and 96 wells microtiter plate method, respectively. Antibiofilm activity of plant extracts was determined in 96 well tissue culture plate. Antiquorum sensing activity was determined by disc diffusion method. 
 
Result: Methanol leaf extract exhibited antimicrobial activity against S. aureus with 19 mm and 7 mm zone of inhibition at 200 mg/mL and 12.5 mg/mL, respectively. Methanol fruit extract also showed antimicrobial activity against S. aureus only. Highest and lowest activities were observed at 200 mg/mL and 25 mg/mL concentrations with 15 mm and 7 mm zone of inhibition, respectively. No antimicrobial activities by either of the extracts were observed against E. coli isolates. The MIC of R. ellipticus methanol leaf and fruit extracts against S. aureus was 0.203125 mg/mL and 0.8125 mg/mL, respectively. The methanol leaf (86.60%) and stem (85.60%) extracts of R. ellipticus showed significant antibiofilm activity against S. aureus isolates, whereas methanol fruit (89.20%) extracts exhibited antibiofilm activity against E. coli isolates at the concentration of 0.05 mg/mL. Significant antiquorum sensing (QS) activities was exhibited by the methanol leaf extract of R. ellipticus at 200 mg/mL concentration against E. coli. This is the first ever report on antibiofilm and anti QS activities of the R. ellipticus plant extracts against E. coli and S. aureus bacteria.</div>

Exploration of Antimicrobial, Antibiofilm and Antiquorum Sensing Activity of the Himalayan Yellow Raspberry (Rubus ellipticus) against Clinical Isolates of Escherichia coli and Staphylococcus aureus

<div>Salmonella has emerged as one of the most important food-borne pathogens for humans as well as animals and the ability of biofilm formation by these bacteria has further aided their survival in unfavorable environment. Characterization of these biofilm producing bacteria isolated from pigs and chicken may lead to formulation of strategies for prevention and control of Salmonella infections. Therefore, the present study was conducted to isolate Salmonella from pigs and poultry of Mizoram, determine their biofilm producing ability by phenotypic and genotypic methods along with their virulence and antimicrobial resistance properties. A total of 15 Salmonella spp. (pig=9, poultry=6) was isolated from 100 faecal samples from pigs and 50 cloacal swabs from poultry and biofilm producing ability of the isolates was determined by microtiter plate assay. A total of 10 (66.67%) isolates were found to be biofilm producer. All the biofilm producing bacterial isolates were investigated for antimicrobial sensitivity and distribution of selected biofilm associated genes (csgA, csgD and adrA), virulence genes (invA, stn and sefA) and antimicrobial resistance (AMR) genes (blaTEM, blaSHV and blaCTX-M). The most prevalent resistance was found against ceftazidime (80%), ceftriaxone (80%), cefixime (70%), cefotaxime (70%), gentamicin (70%), cotrimoxazole (60%) and ampicillin (60%). A total of 7 (70%) isolates were resistant to at least three different classes of antimicrobial agents and considered as multidrug resistant. All the isolates were positive for adrA (100%) but negative for csgA and csgD genes. The most frequent virulence gene was invA (100%) and stn (100%). Among the AMR genes, blaTEM &nbsp;(60%) was found to be the major AMR determinants. Moreover, a total of 7 Salmonella isolates were &nbsp; positive for at least one of t biofilm associated genes, virulence genes and AMR genes.&nbsp;</div>

<div>Molecular detection of biofilm, virulence and antimicrobial resistance associated genes of Salmonella serovars isolated from pig and chicken of Mizoram, India</div>