<div>Background: A study was carried out to screen milk borne Staphylococcus aureus for resistance against Beta lactam antibiotics.&nbsp; 
 
Methods: A total of 45 milk samples were collected over a period of three months from large animal outpatient unit of Madras Veterinary College Hospital, Chennai. Upon collection of samples, ABST followed by its growth in Mannitol Salt Agar was carried out as part of the phenotypic screening. Genotypic screening for Staphylococcus screening was done with the help of PCR by using nuc &nbsp;and mec A primers. MIC for ceftriaxone and cloxacillin was carried out with the samples that were found positive for Staphylococcus aureus. The antibiotic sensitivity pattern is presented: Fluoroquinolones (87.5% sensitive), aminoglycosides (72.5% sensitive), Amoxicillin-Clavulanic acid (Amoxyclave) (72.5% sensitive). The MSA positive samples were subjected to molecular identification with the help of PCR.&nbsp; 
 
Result: The results revealed 10 samples positive for Staphylococcus aureus and 5 among them positive for mecA gene. The MIC results were as follows: MIC50-10.95&micro;g/ml and MIC90- 87.510.95&micro;g/ml for ceftriaxone and MIC50- 43.75 &micro;g/ml and MIC90- 87.5&micro;g/ml for cloxacillin, indicating emergence of resistance. However, further studies are required in a larger sample size that can help us to attain more conclusive results.</div>

<div>Screening of Milk Borne Staphylococcus aureus for Resistance against Beta Lactam Antibiotics</div>

<div>Streptococcus suis (S. suis) is a major pathogen causing economic losses to the swine industry. Norfloxacins are usually used at sub-MIC (Minimum Inhibitory Concentration) doses to prevent S. suis infection. This study demonstrates the effect of norfloxacin sub-MIC on biofilm formation and virulence gene expression in S. suis.It was found that 1/4 MIC of norfloxacin increased biofilm formation in S. suis, the biofilms formed contained a higher number of viable bacteria. Additionally, bacterial growth rates were inhibited at 1/2 MIC of norfloxacin. Furthermore, the mRNA level of S. suis virulence gene cps, ef, sly, fpbs, gdh and gapdh increased by real-time PCR, while the virulence gene mrp decreased at 1/4 MIC. In conclusion, Norfloxacin sub-MICs affects biofilm formation and virulence gene expression in S. suis. These findings suggest that investigating the effect of the administration of antibiotics sub-MICs on bacterial biofilms and infection may lead to the development of future antibiotic treatments modalities.</div>

<div>Norfloxacin Sub-Inhibitory Concentration Affects Streptococcus suis Biofilm Formation and Virulence Gene Expression</div>

<div>Background: Streptococcus suis is a zoonotic pathogen closely related to the respiratory tract of swine. Paeonol is a traditional Chinese medicine with antibacterial effect. This study demonstrated the effect of paeonol on biofilm formation and the expression of virulence factors of Streptococcus suis.&nbsp; 
 
Methods: The minimum inhibitory concentration (MIC) of paeonol on Streptococcus suis was determined by double dilution method. Crystal violet staining method was used to determine the effect of paeonol on the biofilm formation. The effects of paeonol on the morphology and structure of Streptococcus suis biofilm were observed by field emission scanning electron microscopy (FE-SEM). Real-time quantitative PCR (qRT-PCR) was used to detect the expression levels of Streptococcus suis related virulence factors under sub-MIC (1/4 MIC, 1/8 MIC) paeonol. 
 
Result: The results showed the effect of 1/4 MIC and 1/8 MIC paeonol on biofilm formation and mature biofilm was significant (*P&lt;0.05). Under the action of paeonol, the biofilm structure becomes sparse. qRT-PCR results showed that 1/8 MIC paeonol inhibits bacterial adhesion by up-regulating the expression of mrp virulence genes, thereby inhibiting the formation of Streptococcus suis biofilm.</div>

Effects of Paeonol Sub-inhibitory Concentration on Streptococcus suis Biofilm and Expression of Virulence Genes

<div>Background: Antimicrobial resistance is one of the latest challenges facing the scientific community. Raising the drug resistance is caused mainly by indiscriminate usage of antibiotics in human and animal subjects and the spread of antibiotic resistance between the two has an emerging global threat. Hence, current study aimed to study the antimicrobial resistance pattern and molecular detection of antibiotic resistance genes in Staphylococcus aureus and Escherichia coli isolated from mastitis affected cows.&nbsp; 
 
Methods: Milk samples from mastitis affected cows were subjected to antibiotic sensitivity test and screened for presence of Staphylococcus aureus and Escherichia coli using differential growth media. Molecular characterization of Staphylococcus aureus and Escherichia coli was done with the help of PCR by amplification of &lsquo;nuc&rsquo; and &lsquo;uspA&rsquo; gene respectively. MICs of Penicillin and Tetracycline were determined using microdilution method.&nbsp; 
 
Result: Antibiotic sensitivity pattern for Penicillin G, Ampicillin, Amoxycillin, Cefotaxime, Ceftriaxone, Azithromycin, Ciprofloxacin, Gentamicin, Oxytetracycline, Tetracycline and Vancomycin were 74.19%, 100%, 93.50%, 61.29%, 29%, 35.48%, 9.70%, 9.70%, 70.96% and 70.96% &nbsp;respectively. More than 87.90% of the S. aureus and 50% of the E. coli isolated were resistant to &acirc;-lactam antibiotics while 75% of the E.coli and 65.70% of the S. aureus isolated were resistant to Tetracycline antibiotics. The MICs of Penicillin for S.aureus and E.coli are 26.88 &micro;g/ml and 13.54 &micro;g/ml respectively and the MICs of Tetracycline for S. aureus and E. coli are 243.75 &micro;g/ml and 960.93 &micro;g/ml respectively which is 8-9 folds higher than the standard MICs. From the present study, it can be inferred that bovine mastitis cases are highly resistant to antimicrobial drugs. Results further indicate that Staphylococcus aureus and Escherichia coli are both resistant to Penicillin and Tetracycline with very high MIC. &nbsp;</div>

<div>Molecular Characterization of Antibiotic Resistance Gene Pattern of Staphylococcus aureus and Escherichia coli in Mastitis Affected Dairy Cows</div>

Background: Dairy sector is a leading industry in our country. Mastitis being most concerned and frightful disease, not only affecting health of animals but also the economy of the livestock owner. Prevailing status of the antimicrobial resistance makes the treatment of mastitis much more difficult. Biofilm formation in mastitis milk could place difficulty in the treatment of animals as it further increases the possibility of antimicrobial resistance. Essential oils generally being less toxic, could be optimal alternatives to conventional antibiotics, most of these essential oils higher MIC values than antibiotics, needed to be given in increased concentration in feed/water. 
 
Methods: Different dairy farms were screened for mastitis (164 dairy cattle and buffalo) Staphylococcus aureus isolates were identified and characterized phenotypically by standard biochemical tests. The biofilm formation ability was studied by different methods along with the quantitative analysis and MIC of standard drug cefoperazone. 
 
Result: Out of total milk samples 17 samples were identified Staphylococcus aureus positive with Congo red agar (70% positive), Light Microscopy method (52% positive) and Microtiter plate (Crystal Violet) method. (100% sensitivity). The antimicrobial and antibiofilm effect of Cinnamon oil were studied by Microtiter plate method, SEM analysis and confocal techniques. Cinnamon oil gave antibiofilm activity in all the concentration used (1%, 2%, 3%). The MIC of Cefoperazone was in the range of 64 &igrave;g/to 16 &igrave;g/ml. No significant changes were observed on biofilm production at sub-MIC of cefoperazone.

Antimicrobial and Antibiofilm Activity of Cinnamon Oil on Staphylococcus aureus Isolated from Cattle Milk with Mastitis

Background: This research aimed to assess the antifungal potential of oil and organic leaf extracts obtained from Ocimum gratissimum, Kopsia fruticosa and Hibiscus rosa-sinensis against fungal pathogens affecting solanaceous crops. 
 
Methods: Oil of O. gratissimum was obtained by hydro-distilled method using Clevenger apparatus. Leaf extracts of K. fruticosa and H. rosa-sinensis were extracted using three organic solvents namely hexane, ethanol and methanol. The antifungal activity of the oil and organic leaf extracts against the test fungal pathogens was determined by the agar well diffusion method. The efficacy of the oil and organic leaf extracts against the pathogens was evaluated by their minimum inhibitory concentration (MIC), ability to inhibit spore germination and growth kinetic assay. 
 
Result: The oil of O. gratissimum (1000 ppm) significantly inhibited the growth of Cercospora capsici (81.4%), Alternaria alternata (73.7%) and Fusarium oxysporum (68.7%). Hexane extract of K. fruticosa and methanol extract of H. rosa-sinensis (1500 &micro;g/well) displayed strong antifungal activity against Colletotrichum acutatum with inhibition percentages of 75.9% and 82.4% respectively. Similarly, ethanol extract of K. fruticosa and methanol extract of H. rosa-sinensis showed effective inhibition against C. capsici and A. alternata. The oil of O. gratissimum showed MIC values of 50, 100 and 200 &micro;g/mL against C. capsici, A. alternata and F. oxysporum respectively. Ethanol extract of K. fruticosa showed MIC values ranging from 100 to 350 &micro;g/mL, while H. rosa-sinensis methanol extract displayed MIC values ranging from 50 to 200 &micro;g/mL against the fungal pathogens. The oil extract also demonstrated strong inhibition of spore germination of the test fungi. Our study suggests the potential of plant-derived essential oils and extracts as effective antifungal agents for crop protection.

In vitro Antifungal Efficacy of Some Plant Extracts against Fungal Pathogens Causing Diseases in Solanaceous Crops

<div>Background: Fungal phytopathogens are one of the main causes of deterioration of plant growth and productivity. Reliability of farmers on chemical fungicides poses a threat to humans and the environment. Therefore, exploration and uses of green and biological alternatives should be encouraged in the field of agriculture in order to maintain the overall health of a country. Plant essential oil is one such alternative that is currently researched and holds promises in unlocking the solution to this problem.&nbsp; 
 
Methods: Effect of the oil extracted from K. galanga by hydro-distillation against fungal phytopathogens isolated from different plant parts were tested using two different methods of inhibition viz., by direct contact method (M1) and volatile/fumigation method (M2). The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) for both methods were also determined. Scanning electron microscopy (SEM) was also used to show the effect of oil on the physiology of the pathogens. 
 
Result: MIC was in the range 1.5-6 &micro;l mL-1 for M1, whereas for M2 the MIC was in the range 2-10 &micro;l mL-1 air. The MFC for M1 ranges from 2-6 &micro;l mL-1, with the exception of Fusarium sp. and Cercospora sp. However for volatile/ fumigation assay, the MFC could not be determined. Thus the effectiveness of the oil for inhibiting the phytopathogens differ for different fungi and the methods used.&nbsp;</div>

​Antifungal Activity of Essential oil Extracted from Kaempferia galanga L. Rhizome against Fungal Phytopathogens

Background: The human skin is a natural barrier that protects against external stress, but its physiological structure can be compromised when it gets damaged. In the field of medical science, wounds are a significant issue that requires immediate attention. Lavandula species are used in the food, perfume and cosmetics industries due to their antimicrobial, anti-inflammatory and wound-healing properties.&nbsp; 
 
Methods: The present study was done to assess the biocompatibility, antimicrobial and wound-healing potential of L. dentata leave methanolic extract (LE) that is cultivated in the Taif region of Saudi Arabia. The biocompatibility of LE was analyzed against the normal human skin fibroblast (HSF) cell line using SRB assay. A quarter of LE IC50 was used for wound healing assay. Finally, Escherichia Coli, Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pyogenes were used to determine LE antibacterial potential through the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) measurement.&nbsp; 
 
Result: LE appears safe on HSF cell line with IC50 = 97 mg/mL. LE decreased wound width, wound area and the mean cell migratory rate of wound border cells during scratch closure, while increased the wound closure% in a time-dependent manner compared to negative control. LE shows antimicrobial potential against all four strains at MIC and MBC&gt;3.0 mg/mL, except for Streptococcus pyogenes MIC= 3.0 mg/mL. In conclusion, LE offers therapeutic benefits against wound healing with an antimicrobial effect, however, higher concentrations of LE should be used to assess its effect.

Biocompatibility, Antimicrobial and Wound Healing Activities of Lavandula dentata Leaves Extract

<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>