Antimicrobial property of lemongrass (Cymbopogon citratus) oil against pathogenic bacteria isolated from pet turtles

B.C.J. De Silva,정원기,사브리나 호세인,S.H.M.P. Wimalasena,H.N.K.S. Pathirana,허강준 한국실험동물학회 2017 Laboratory Animal Research Vol.33 No.2

The usage of essential oils as antimicrobial agents is gaining attention. Besides, pet turtles were known to harbor a range of pathogenic bacteria while the turtle keeping is a growing trend worldwide.The current study examined the antimicrobial activity of lemon grass oil (LGO) against seven species of Gram negative bacteria namely; Aeromonas hydrophila, A. caviae, Citrobacter freundii, Salmonella enterica, Edwardsiella tarda, Pseudomonas aeruginosa, and Proteus mirabilis isolated from three popular species of pet turtles. Along with the results of disc diffusion, minimum inhibitory and minimum bactericidal concentration (MIC and MBC) tests, LGO was detected as effective against 6 species of bacteria excluding P. aeruginosa. MIC of LGO for the strains except P. aeruginosa ranged from 0.016 to 0.5% (V/V). The lowest MIC recorded in the E. tarda strain followed by A. hydrophilla, C. freundii, P. mirabilis, and S. enterica. Interestingly, all the bacterial species except E. tarda were showing high multiple antimicrobial resistance (MAR) index values ranging from 0.36 to 0.91 upon the 11 antibiotics tested although they were sensitive to LGO.

Chitosan nanoparticles: A positive immune response modulator as display in zebrafish larvae against <i>Aeromonas hydrophila</i> infection

Nikapitiya, Chamilani,Dananjaya, S.H.S.,De Silva, B.C.J.,Heo, Gang-Joon,Oh, Chulhong,De Zoysa, Mahanama,Lee, Jehee ACADEMIC PRESS LTD 2018 FISH AND SHELLFISH IMMUNOLOGY Vol.76 No.-

<P><B>Abstract</B></P> <P>Chitosan nanoparticles (CNPs) were synthesized by ionic gelation method and its immunomodulatory properties were investigated in zebrafish larvae. Average particle size and zeta potential were 181.2 nm and +37.2 mv, respectively. Initially, toxicity profile was tested in zebrafish embryo at 96 h post fertilization (hpf) stage using medium molecular weight chitosan (MMW-C) and CNPs. At 5 μg/mL, the hatching rate was almost similar in both treatments, however, the survival rate was lower in MMW-C compared to CNPs exposure, suggesting that toxicity effect of CNPs in hatched larvae was minimal at 5 μg/mL compared to MMW-C. Quantitative real time PCR results showed that in CNPs exposed larvae at 5 days post fertilization (5 dpf) stage, immune related (<I>il-1β</I>, <I>tnf-α</I>, <I>il-6</I>, <I>il-10</I>, <I>cxcl-18b</I>, <I>ccl34a.4</I>, <I>cxcl-8a</I>, <I>lyz-c</I>, <I>defβl-1</I>, <I>irf-1a</I>, <I>irf-3</I>, <I>MxA</I>) and stress response (<I>hsp-70</I>) genes were induced. In contrast, basal or down regulated expression of antioxidant genes (<I>gstp-1</I>, <I>cat</I>, <I>sod-1</I>, <I>prdx-4</I>, <I>txndr-1</I>) were observed. Moreover, zebrafish larvae (at 5 dpf stage) exposed to CNPs (5 μg/mL) showed higher survival rate at 72 h post infection stage against pathogenic <I>Aeromonas hydrophila</I> challenge compared to controls. These results suggest that although CNPs can have toxic effects to the larvae at higher doses, CNPs exposure at 5 μg/mL could enhance the immune responses and develop the disease resistance against <I>A. hydrophila</I>, which could be attributed to its strong immune modulatory properties.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesized CNPs at 5 μg/L exposure was non-toxic to zebrafish at 96 hpf stage. </LI> <LI> CNPs showed immune modulatory and disease resistant against <I>A. hydrophila</I> in 5 dpf stage zebrafish after non-toxic exposure. </LI> <LI> Biodegradable CNPs could be a potential immunostimulant for larval aquaculture. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Quinolone susceptibility and genetic characterization of Salmonella enterica subsp. enterica isolated from pet turtles

B.C.J. De Silva,사브리나 호세인,S.H.M.P. Wimalasena,H.N.K.S. Pathirana,Mitchell Wendt,허강준 한국실험동물학회 2017 Laboratory Animal Research Vol.33 No.2

Turtle-borne Salmonella enterica owns significance as a leading cause in human salmonellosis. The current study aimed to determine the quinolone susceptibility and the genetic characteristics of 21 strains of S. enterica subsp. enterica isolated from pet turtles. Susceptibility of four antimicrobials including nalidixic acid, ciprofloxacin, ofloxacin, and levofloxacin was examined in disk diffusion and MIC tests where the majority of the isolates were susceptible to all tested quinolones. In genetic characterization, none of the isolates were positive for qnr or aac(6’)-Ib genes and no any target site mutations could be detected in gyrA, gyrB, and parC quinolone resistance determining regions (QRDR). In addition, neighborjoining phylogenetic tree derived using gyrA gene sequences exhibited two distinct clads comprising; first, current study isolates, and second, quinolone-resistant isolates of human and animal origin. All results suggest that studied strains of S. enterica subsp. enterica isolated from pet turtles are susceptible to quinolones and genetically more conserved with regards to gyrA gene region.

Aminoglycoside susceptibility and genetic characterization of Salmonella enterica subsp. enterica isolated from pet turtles

( Sabrina Hossain ),( B. C. J. De Silva ),( S. H. M. P. Wimalasena ),( H. N. K. S. Pathirana ),( Gang-joon Heo ) 한국가축위생학회 2017 韓國家畜衛生學會誌 Vol.40 No.1

Salmonella enterica subsp. enterica is a common microbial flora in pet turtles, which could opportunistically become pathogenic to human. Their possession of aminoglycoside resistance genes has important significance both in humans and animal medicine. In this study, twenty-one Salmonella enterica subsp. enterica were isolated from thirty-five individual turtles purchased from pet shops and online markets in Korea. In order to characterize the aminoglycoside susceptibility patterns, antimicrobial susceptibility tests were performed against gentamicin, amikacin and kanamycin of aminoglycoside antimicrobial group. Each of the isolates showed susceptibility to all tested aminoglycosides in disk diffusion and minimum inhibitory concentration (MIC) tests. PCR assay was carried out to determine aminoglycoside resistance genes, integron and integron mediated aminoglycoside genes. None of the isolates showed aac(3)-IIa, aac-(6′)-Ib, armA, aphAI-IAB aminoglycoside resistance genes. Only, five isolates (24%) harbored class 1 integron related IntI1 integrase gene. The results suggest that Salmonella enterica subsp. enterica strains isolated from pet turtles are less resistance to aminoglycosides and don`t harbor any aminoglycosides resistance genes.

Aminoglycoside susceptibility and genetic characterization of Salmonella enterica subsp. enterica isolated from pet turtles

사브리나 호세인,B.C.J. De Silva,S.H.M.P. Wimalasena,H.N.K.S. Pathirana,허강준 한국동물위생학회 2017 韓國家畜衛生學會誌 Vol.40 No.1

Salmonella enterica subsp. enterica is a common microbial flora in pet turtles, which could opportunisti-cally become pathogenic to human. Their possession of aminoglycoside resistance genes has important significance both in humans and animal medicine. In this study, twenty-one Salmonella enterica subsp. enterica were isolated from thirty-five individual turtles purchased from pet shops and online markets in Korea. In order to characterize the aminoglycoside susceptibility patterns, antimicrobial susceptibility tests were performed against gentamicin, amikacin and kanamycin of aminoglycoside antimicrobial group. Each of the isolates showed susceptibility to all tested aminoglycosides in disk diffusion and minimum inhibitory concentration (MIC) tests. PCR assay was carried out to determine aminoglycoside resistance genes, integron and integron mediated aminoglycoside genes. None of the isolates showed aac(3)-IIa, aac-(6′)-Ib, armA, aphAI-IAB aminoglycoside resistance genes. Only, five isolates (24%) har-bored class 1 integron related IntI1 integrase gene. The results suggest that Salmonella enterica subsp. enterica strains isolated from pet turtles are less resistance to aminoglycosides and don’t harbor any aminoglycosides resistance genes.

Incidence of Bladder Cancer in Sri Lanka: Analysis of the Cancer Registry Data and Review of the Incidence of Bladder Cancer in the South Asian Population

Weranja K. B. Ranasinghe,Daswin De Silva,M.V.C. De Silva,Tamra I J Ranasinghe,Nathan Lawrentschuk,Damien Bolton,Raj Persad 대한비뇨의학회 2012 Investigative and Clinical Urology Vol.53 No.5

Purpose: To investigate the incidence of bladder cancer (BC) in Sri Lanka and to compare risk factors and outcomes with those of other South Asian nations and South Asian migrants to the United Kingdom (UK) and the United States (US). Materials and Methods: The incidence of BC in Sri Lanka was examined by using two separate cancer registry databases over a 5-year period. Smoking rates were compiled by using a population-based survey from 2001 to 2009 and the relative risk was calculated by using published data. Results: A total of 637 new cases of BC were diagnosed over the 5-year period. Sri Lankan BC incidence increased from 1985 but remained low (1.36 and 0.3 per 100,000 in males and females) and was similar to the incidence in other South Asian countries. The incidence was lower, however, than in migrant populations in the US and the UK. In densely populated districts of Sri Lanka, these rates almost doubled. Urothelial carcinoma accounted for 72%. The prevalence of male smokers in Sri Lanka was 39%, whereas Pakistan had higher smoking rates with a 6-fold increase in BC. Conclusions: Sri Lankan BC incidence was low, similar to other South Asian countries (apart from Pakistan), but the actual incidence is likely higher than the cancer registry rates. Smoking is likely to be the main risk factor for BC. Possible under-reporting in rural areas could account for the low rates of BC in Sri Lanka. Any genetic or environmental protective effects of BC in South Asians seem to be lost on migration to the UK or the US and with higher levels of smoking, as seen in Pakistan. Purpose: To investigate the incidence of bladder cancer (BC) in Sri Lanka and to compare risk factors and outcomes with those of other South Asian nations and South Asian migrants to the United Kingdom (UK) and the United States (US). Materials and Methods: The incidence of BC in Sri Lanka was examined by using two separate cancer registry databases over a 5-year period. Smoking rates were compiled by using a population-based survey from 2001 to 2009 and the relative risk was calculated by using published data. Results: A total of 637 new cases of BC were diagnosed over the 5-year period. Sri Lankan BC incidence increased from 1985 but remained low (1.36 and 0.3 per 100,000 in males and females) and was similar to the incidence in other South Asian countries. The incidence was lower, however, than in migrant populations in the US and the UK. In densely populated districts of Sri Lanka, these rates almost doubled. Urothelial carcinoma accounted for 72%. The prevalence of male smokers in Sri Lanka was 39%, whereas Pakistan had higher smoking rates with a 6-fold increase in BC. Conclusions: Sri Lankan BC incidence was low, similar to other South Asian countries (apart from Pakistan), but the actual incidence is likely higher than the cancer registry rates. Smoking is likely to be the main risk factor for BC. Possible under-reporting in rural areas could account for the low rates of BC in Sri Lanka. Any genetic or environmental protective effects of BC in South Asians seem to be lost on migration to the UK or the US and with higher levels of smoking, as seen in Pakistan.

Aminoglycoside susceptibility and genetic characterization of Salmonella enterica subsp. enterica isolated from pet turtles

Hossain, Sabrina,De Silva, B.C.J.,Wimalasena, S.H.M.P.,Pathirana, H.N.K.S.,Heo, Gang-Joon The Korean Society of Veterinary Service 2017 韓國家畜衛生學會誌 Vol.40 No.1

Salmonella enterica subsp. enterica is a common microbial flora in pet turtles, which could opportunistically become pathogenic to human. Their possession of aminoglycoside resistance genes has important significance both in humans and animal medicine. In this study, twenty-one Salmonella enterica subsp. enterica were isolated from thirty-five individual turtles purchased from pet shops and online markets in Korea. In order to characterize the aminoglycoside susceptibility patterns, antimicrobial susceptibility tests were performed against gentamicin, amikacin and kanamycin of aminoglycoside antimicrobial group. Each of the isolates showed susceptibility to all tested aminoglycosides in disk diffusion and minimum inhibitory concentration (MIC) tests. PCR assay was carried out to determine aminoglycoside resistance genes, integron and integron mediated aminoglycoside genes. None of the isolates showed aac(3)-IIa, aac-(6')-Ib, armA, aphAI-IAB aminoglycoside resistance genes. Only, five isolates (24%) harbored class 1 integron related IntI1 integrase gene. The results suggest that Salmonella enterica subsp. enterica strains isolated from pet turtles are less resistance to aminoglycosides and don't harbor any aminoglycosides resistance genes.

Antibacterial activity of essential oil from lavender (Lavandula angustifolia) against pet turtle-borne pathogenic bacteria

사브리나 호세인,허홍회,B.C.J. De Silva,S.H.M.P. Wimalasena,H.N.K.S. Pathirana,허강준 한국실험동물학회 2017 Laboratory Animal Research Vol.33 No.3

Pet turtles are well-known to harbor an array of bacterial pathogens which can cause zoonotic infections in humans as well as opportunistic infections in the turtles itself. Essential oils are the natural plant extracts which have been traditionally used for disease treatment. In the present study, the essential oil of lavender (EOL) was examined for its antibacterial activity against thirty-eight strains of turtle-borne pathogenic bacteria belonging to seven species; Aeromonas hydrophila, A. caviae, A. dhakensis, Citrobacter freundii, Proteus mirabilis, Salmonella enterica and Pseudomonas aeruginosa. Antibacterial activity of EOL was tested by means of disk diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) tests. In addition, the antimicrobial susceptibility pattern of 11 commonly used antimicrobials was examined and the multiple antibiotic resistance (MAR) index was calculated. The results revealed that EOL was active against all tested turtle-borne pathogenic bacteria except P. aeruginosa. The range of MIC and MBC values of EOL against isolates except P. aeruginosa were recorded as 0.5-1% (V/V) and 0.5-2% (V/V), respectively. The MBC/MIC ratio was detected as <4, revealing that the tested EOL was bactericidal. Besides, most of the isolates were resistant to different antimicrobials in antimicrobial disk diffusion test. MAR index values of the tested strains were ranging from 0.27 to 0.91. The outcomes indicate that EOL has a potential to be used as an antibacterial agent against pathogenic bacteria isolated from pet turtles.

Effects of Castor Meal on the Growth Performance and Carcass Characteristics of Beef Cattle

Diniz, L.L.,Filho, S.C. Valadares,Campos, J.M.S.,Valadares, R.F.D.,Da Silva, L.D.,Monnerat, J.P.I.S.,Benedeti, P.B.,De Oliveira, A.S.,Pina, D.S. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.10

The purpose of this study was to evaluate the effect of replacing soybean meal with treated castor meal with (CMT) or without lime (CMNT) on the nutrient intake, performance, carcass characteristics, and yield of commercial cuts of beef cattle from a feedlot. Thirty male, castrated, crossbreed zebu cattle were used in the study, with an average initial weight of $360{\pm}30.27\;kg$. Five animals were used as a control group and were slaughtered at the beginning of the experiment; the remaining animals (n = 25) were distributed in random blocks (repetitions), with body weight as the criterion for block assignment. The animals were fed a diet containing 65% corn silage and 35% of concentrate on dry matter (DM) basis. Five diets consisted of four levels of soybean meal (SM) substituted with CMT (0, 33, 67 and 100%) on a DM basis and a diet with 100% of SM replaced with CMNT. At the end of the experiment, all animals were slaughtered, and their gastrointestinal tracts were emptied to determine their empty body weights (EBW). No significant effects were observed (p>0.05) for the substitution of soybean meal with CMT on intake of dietary nutrients, the average daily body weight gain (ADG) or EBW gain (EBWG). In spite of greater (p<0.05) ricin intake for the diet containing CMNT (3.06 mg/kg BW) compared to the CMT diet (0.10 mg/kg BW/d), there were no effects (p>0.05) on intake of dietary nutrients, ADG or EBWG. The average intake of DM and the ADG were 10,664.63 and 1,353.04 g/d, respectively. Regarding carcass characteristics, only carcass yield in relation to body weight was linearly reduced (p<0.05) upon substitution of SM by CMT. There was no effect (p>0.05) of the substitution of SM by CMT or CMNT on the yield of carcass basic cuts. CMT prices that are higher than 85% of the SM price do not economically justify the use of CMT. For CMT prices between 20 and 80% of the SM price, the optimal level was 67% substitution, while for prices below 15% of the SM price, the optimal level was 100% substitution with CMT. It can be concluded that treated castor meal with 6% lime can totally replace soybean meal in beef cattle diets.