• Journal of Microbiology and Biotechnology
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• v.33 no.5
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• pp.668-679
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• 2023

Edwardsiella tarda is one of the most significant fish pathogens, causes edwardsiellosis in a variety of freshwater fish species, and its antibiotic resistance against multiple drugs has made it a health risk worldwide. In this study, we aimed to investigate the antibiotic resistance (ABR) genes of E. tarda and establish its antibiotic susceptibility. Thus, 540 fish (299 Oreochromis niloticus, 138 O. mossambicus, and 103 O. aureus) were collected randomly from twelve fish farms in three districts of Punjab in Pakistan. E. tarda was recovered from 147 fish showing symptoms of exophthalmia, hemorrhages, skin depigmentation, ascites, and bacteria-filled nodules in enlarged liver and kidney. Antimicrobial susceptibility testing proved chloramphenicol, ciprofloxacin, and streptomycin effective, but amoxicillin, erythromycin, and flumequine ineffective in controlling edwardsiellosis. Maximum occurrence of qnrA, blaTEM, and sul3 genes of E. tarda was detected in 45% in the liver, 58%, and 42% respectively in the intestine; 46.5%, 67.2%, and 55.9% respectively in O. niloticus; 24%, 36%, and 23% respectively in summer with respect to fish organs, species, and season, respectively. Motility, H₂S, indole, methyl red, and glucose tests gave positive results. Overall, E. tarda infected 27.2% of fish, which ultimately caused 7.69% mortality. The Chi-squared test of independence showed a significant difference in the occurrence of ABR genes of E. tarda with respect to sampling sites. In conclusion, the misuse of antibacterial agents has led to the emergence of ABR genes in E. tarda, which in association with high temperatures cause multiple abnormalities in infected fish and ultimately resulting in massive mortality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.7
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• pp.1003-1007
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• 2013

In this study, the antibacterial activities of selected barleys (UB, unhulled barley; PB, pearl barley; and NB, naked barley) and wheat (WG, wheat with germ and endosperm) extracts were evaluated against the food-borne pathogens Staphylococcus aureus KCTC 1927, Escherichia coli KCTC 2593, Salmonella Typhimurium KCTC 2054, and Bacillus cereus KCTC 1014. The amount of the antibacterial biomarker, 2,6-dimethoxy-1,4-benzoquinone (DMBQ), present in selected barleys and wheat, was measured by HPLC. Furthermore, antioxidant activity of samples was determined using the oxygen radical absorbance capacity (ORAC) assay. WG ($22.35{\pm}0.04mm$) was found to be highly inhibitory to Staphylococcus aureus followed by UB ($17.91{\pm}0.10mm$), PB ($16.87{\pm}0.05mm$), and NB ($15.69{\pm}0.20mm$). The antibacterial activity of the selected grains was correlated with antioxidant activities and the amount of DMBQ (Pearson's correlation coefficient, 0.7831). The antioxidant activity of the selected grains was also correlated with the total phenolic content (Pearson's correlation coefficient, 0.9934). WG extract showed significantly higher antibacterial activity, compared with barley extracts such as UB, PB, and NB. The results of this study suggest that barley has a potential in the development of natural antimicrobials and food preservatives for controlling food-borne pathogens.

• Food Science and Preservation
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• v.10 no.3
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• pp.421-426
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• 2003

Effects of acid, salt, heat treatment and natural antimicrobials on survival of E. coli O157:H7 CDF1, A. sobria CDF3 and S. aureus CDF2 isolated from surface of carcass in minced meat was investigated. The growth of E. coli O157:H7 CDF1 and A. sobria CDF3 inhibited in minced meat containing above 4％ NaCl but not in 1％ lactic acid. The growth of S. aureus CDF2 was not inhibited significantly by addition of 4％ NaCl but inhibited completely in minced meat containing 1％ lactic acid. Survival of A. sorbia CDF3 did not show any differences during storage at 4 and 10$^{\circ}C$. E. coli O157:H7 CDF10 and A. sobria CDF3 did not detect after heat treatment at 60$^{\circ}C$ for 10 min but S. aureus CDF2 decreased only 1 log after the same treatment. Viable cell of E. coli O157:H7 CDF1 decreased 2 log in TSB containing 0.5％ Oolong tea extract after incubation for 12 hr compared with control but A. sobria CDF3 and S. aureus CDF2 did not detect at the same condition. The growth of E. coli O157:H7 CDF1, A. sobria CDF3 and S. aureus CDF2 was not inhibited by addition of 0.3％ Oolong tea extract but inhibited by addition of 0.5％ Oolong tea extract in minced meat at 20$^{\circ}C$ for 24hr.

• Childhood Kidney Diseases
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• v.10 no.1
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• pp.18-26
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• 2006

Purpose : Empirical antimicrobial treatment is indicated before bacteriological results are available for young children with febrile UTI to minimize renal scarring. To ensure appropriate therapy, knowledge of the prevalence of causative organisms and their susceptibility patterns to antimicrobials is mandatory. We performed a retrospective analysis investigating the local prevalence and resistance patterns of uropathogens, primarily E. coli, isolated from community-acquired UTIs. Methods : A total of 103 positive urine cultures from children with febrile UTI collected at Bundang CHA General Hospital from February 2004 to February 2005 were analyzed. Inclusion criteria were fever higher than $37.5^{\circ}C$, significant bacteriuria with single strain growth of at least 10s colony forming units/mL urine, and leukocyturia >5/HPF. Results : E. coli(89.3%) was the leading uropathogen followed by Enterococcus spp.(3.9%) Klebsiella spp.(2.9%), Citrobctcter spp.(1.9%) and Enterobacter spp.(1.9%). E. coli strains revealed a low proportion of antimicrobial susceptibility to ampicillin(AMP; 27.2%) ampicillinsulbactam(AMS; 34.8%) and trimethoprim-sulfamethoxazole(SXT; 65.2%). Susceptibility patterns to cephalosporins were as follows; cefazolin(1st generation; 91.3%), cefoxitin(2nd; 100%), ceftriaxone(3rd; 97.8%) and cefepime(4th; 97.8%). Three E. coli isolates produced ex tended - spectrum beta-lactamase(ESBL). Conclusion : Empirical treatment with AMP, AMS and SXT, which are commonly used in pediatric clinics, is not recommended for childhood UTI due to high incidence of resistance. The high level of susceptibility to cephalosporins makes these drugs reasonable alternatives. However the emergence of ESBL-producers, even though they are quite few, may have an impact on cephalosporin treatment in the future. (J Korean Soc Pediatr Nephrol 2006;10:18-26)

• Journal of fish pathology
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• v.23 no.1
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• pp.57-67
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• 2010

Effects of temperature ($13{\pm}1.5^{\circ}C$, $23{\pm}1.5^{\circ}C$) on the pharmacokinetic properties of nalidixic acid (NA), piromidic acid (PA) and oxolinic acid (OA) were studied after oral administration to cultured olive flounder, Paralichthys olivaceus. Serum concentrations of these antimicrobials were determined after oral administration of a single dosage of 60 mg/kg body weight (average 700 g). At $23{\pm}1.5^{\circ}C$, the peak serum concentrations of NA, PA and OA, which attained at 10 h, 24 h and 30 h post-dose, were 11.55, 3.79 and $1.12{\mu}g/m\ell$, respectively. At $13{\pm}1.5^{\circ}C$, the peak serum concentrations of NA, PA and OA, which attained at 10 h, 15 h and 30 h post-dose, were 6.36, 1.4 and $1.01{\mu}g/m\ell$, respectively. Better absorption of NA and PA was noted at $23{\pm}1.5^{\circ}C$ compared to $23{\pm}13^{\circ}C$. The elimination of NA from serum of olive flounder was considerably faster at $23{\pm}1.5^{\circ}C$ than at $13{\pm}1.5^{\circ}C$. However, both absorption and elimination of OA were not affected significantly by temperature. The kinetic profile of absorption, distribution and elimination of these antimicrobials in serum were analyzed by fitting to a one- and two compartment model, with WinNonlin program. In the one compartment model for NA, AUC, Tmax and Cmax at $23{\pm}1.5^{\circ}C$ were $258.26{\mu}g{\cdot}h/m\ell$, 10.67 h and $8.91{\mu}g/m\ell$, respectively. The AUC, $T_{max}$ and $C_{max}$ at $13{\pm}1.5^{\circ}C$ were $341.45 {\mu}g{\cdot}h/m\ell$, 7.72 h and $6.23{\mu}g/m\ell$, respectively. In the one compartment model for PA, AUC, $T_{max}$ and $C_{max}$ at $23{\pm}1.5^{\circ}C$ were $248.12{\mu}g{\cdot}h/m\ell$, 21.15 h and $3.09{\mu}g/m\ell$, respectively. The AUC, $T_{max}$ and $C_{max}$ at $13{\pm}1.5^{\circ}C$ were $103.89{\mu}g{\cdot}h/m\ell$, 12.89 h and $1.22{\mu}g/m\ell$, respectively. In the two compartment model for OA, AUC, $T_{max}$ and $C_{max}$ at $23{\pm}1.5^{\circ}C$ were $138.20{\mu}g{\cdot}h/m\ell$, 23.95 h and $1.06{\mu}g/m\ell$, respectively. The AUC, $T_{max}$ and $T_{max}$ at $13{\pm}1.5^{\circ}C$ were $159.10{\mu}g{\cdot}h/m\ell$, 28.03 h and $1.02{\mu}g/m\ell$, respectively.

• Korean Journal of Veterinary Research
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• v.37 no.2
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• pp.389-403
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• 1997

Survey on MIC of antimicrobial drugs and its treatment efficacy in mice were conducted for the strains of Escherichia coli and Salmonella spp isolated from feces of young domestic animals with diarrhea in 1996. A total of 338 strains of E coli and 61 strains of Salmonella spp were examined for the susceptibility to 20 antibiotics and 7 synthetic antimicrobial drugs. The results indicated that the majority of strains were susceptible to amikacin(93.5%), cefoperazone/sulbactam(93.5%), cefotaxim(93.3%), cefomandole(92.8%), cefoperazone(91.6%) and ciprofloxacin(85.1%), in order. Although gentamicin, ciprofloxacin and norfloxacin showed the relatively low MIC distributions, erythromycin, doxycycline, sulfamethoxazole and oxytetracycline revealed the high MIC distributions to most of isolates. The $MIC_{90}$ of antimicrobials for E coli were > $62.5{\mu}g/ml$ in gentamicin, $2.0{\mu}g/ml$ in ciprofloxacin, $1.0{\mu}g/ml$ in norfloxacin, > $500{\mu}g/ml$ in erythromycin, $125{\mu}g/ml$ in doxycycline, > $1000{\mu}g/ml$ in sulfamethoxazole and > $250{\mu}/ml$ in oxytetracycline. In general, the MIC of E coli isolates was higher than that of Salmonella spp isolates. Although variation in synergism or additivity of antibiotic combinations were demonstrated, ampicillin-gentamicin was the most efficacious combination both against E coli and Salmonella spp with the fluctuation of 7.7-77.5%. In the experiment of treatment efficacy in mice, the highest survival ratio(83.3%) after challenge with pathogenic E coli and Salmonella typhimurium was detected in the group treated with gentamicin.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.239-247
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• 2015

This experiment was conducted to obtain the have higher contents of pharmaceutical constituents as well as higher yield from colchicine induced diploid and tetraploid extracts of Platycodon grandiflorum. In order to determine the biological activity, this study was focused to evaluate the cytotoxicity, antimicrobial on the bronthus disease bacteria, antioxidant enzyme activity of diploid and tetraploid extracts in P. grandiflorum. The activities of antioxidant enzyme according to different solvent extracts were measured as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). The cytotoxicity of methanol extracts of P. grandiflorum showed significant differences between tetraploid and diploid. That is, the cytotoxic effect against human cancer cell was higher in tetraploid than in diploid. At all extracts concentration, tetraploid samples showed high toxicity and the $IC_{50}$ (concentration causing 50% cell death) value showed the highest on HCT-116 cell ($105.91{\mu}g/mL$), and exhibited significant activity against the Hep 3B cell ($140.67{\mu}g/mL$), SNU-1066 cell ($154.01{\mu}g/mL$), Hela cell ($158.37{\mu}g/mL$), SNU-601 cell ($182.67{\mu}g/mL$), Calu-6 cell ($190.42{\mu}g/mL$), MCF-7 cell ($510.19{\mu}g/mL$). Antimicrobial activities of diploid P. grandiflorum were relatively low compared to tetraploid P. grandiflorum on most of the bacterial strains. In tetraploid P. grandiflorum, K. pneumoniae showed the clear zone formation (18~19 mm) of growth inhibition, followed by the clear zone formation of 13~15 mm on C. diphtheria and S. pyogenes. The antimicrobial activities in diploid P. grandiflorum were the highest on K. pneumonia (14~15 mm), and showed the clear zone formation of 11~12 mm on C. diphtheria and 12~13 mm on S. pyogenes. The antimicrobial activity is thought to look different depending on the bacterial strains and the polyploidy of P. grandiflorum. The root extract of P. grandiflorum had the highest (97.2%) SOD enzyme activity in ethyl acetate partition layer of tetraploid while water partition layer of diploid showed the lowest (48.6%) SOD enzyme activity. The activity of CAT showed higher values in the root of tetraploid than in the diploid of P. grandiflorum in all partition layers except butyl alcohol. The activities of APX and POD showed higher values in the root of tetraploid than in the diploid of P. grandiflorum in all fraction solvents except water layer. These results indicate that the tetraploid P. grandiflorum can be used as a source for developing cytotoxic agent and antimicrobials which can act against bronchus diseases bacterial strains.

• Journal of Life Science
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• v.23 no.9
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• pp.1133-1139
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• 2013

During the collection of boar semen, bacterial contamination usually occurs. The contamination has deleterious effects both on semen quality and on sow fertility. The majority of contaminants are gram-negative bacteria, especially Serratia marcescens. In this study, we developed a PCR assay for the identification of S. marcescens targeting the luxS gene (GenBank no. EF164926). S. marcescens yielded a specific 306 bp PCR product. However, no amplification was observed in the other strains tested. The detection limit of PCR was $50pg/{\mu}l$ of template DNA of S. marcescens. The antimicrobial susceptibility patterns of S. marcescens isolated from boar semen were tested using the disk diffusion method. Gentamicin, ceftiofur, florfenicol, and neomycin showed high sensitivity in this test. The minimum inhibitory concentration (MIC) was also determined by the broth microdilution method. The $MIC_{90}$ values of ceftiofur, enrofloxacin, gentamicin, and neomycin were 8, 8, 8, and $16{\mu}g/ml$, respectively. These results indicate that PCR amplification of the luxS gene is a reliable and effective method for the identification of S. marcescens and that ceftiofur, enrofloxacin, gentamicin, and neomycin are effective semen extenders for controlling S. marcescens.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.591-594
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• 2019

Some strains of Escherichia coli are categorized as pathogenic bacteria and alternative antimicrobials including bacteriophages for controlling these bacteria have been studied. In this study we screened antimicrobial candidates that present synergistic inhibition of the growth of E. coli DH5α as a model when co-treated with the bacteriophage ECP27 to target the bacteria. As candidates, CaCl₂, lactic acid, and citric acid were tested. CaCl₂ showed a synergistic inhibition against the strain by dose-dependent manner at 6 h of incubation but the viable cell count was recovered at 12 h. However, lactic acid and citric acid at 30 mM concentration showed synergistic inhibitions at 6 h of incubation and cleared the viable cells of E. coli DH5α at 12 h when co-treated with the bacteriophage even though lactic acid or citric acid alone was effective. Therefore, co-treatment using the bacteriophage and organic acids such as lactic acid and citric acid can be a solution for synergistic inhibition of the growth of E. coli.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.155-160
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• 2011

Probiotics has currently attracted for means of preventive treatment measurement instead of using non-specific and broad spectrum antimicrobials. In previous studies, two main probiotics species, Lactobacillus and Bifidobateria, showed the reduction of DMFS and S. mutans counts. However, the timing of introducing probiotic species to oral cavity is not clear. The aim of this study is to evaluate the changes of binding ability of S. mutans in various concentrations and inoculation time of L. rhamnosus GG. Adding the following concentration of L. rhamnosus GG, $1{\times}10^6$ CFU, $1{\times}10^7$ CFU and $1{\times}10^8$ CFU, to S. mutans medium demonstrates significant reduction of S. mutans counts. Additionally, more reduction was observed when L. rhamnosus were inoculated prior to S. mutans or simultaneously inoculated compared to when S. mutans were inoculated prior to L. rhamnosus after 3 hours of incubation. Based on this research, the timing of introducing probiotics should be considered when probiotics are utilized as a preventive treatment measurement.