• Microbiology and Biotechnology Letters
• /
• v.35 no.1
• /
• pp.17-25
• /
• 2007

The kinds and quantity of antimicrobial agents used for cattle (animal industry) may be considerable, suggesting the possibility that pathogenic bacteria which cannot be extirpated by the existing antimicrobial agents could appear. Ten cattle, pig and chicken farms, respectively, were randomly selected from 5 provinces in Korea and the samples were collected from excrement, manure, underground water, farmers' hands and the neishboring environment. h total of 299 samples were examined and 197 of Escherichia coli, 13 of Campylobacter jejun/coli, 223 of Enterococcus faecium/faecalis and 42 of Staphylococcus aureus isolates were collected. All isolates were screened for antimicrobial resistance: 69.4% of E. coli (137/197 strains), 78.6% of S. aureus (33/42 strains), and 82.1% of E. faecium/faecalis (183/223 strains) were resistant to one antimicrobial agent and all of C. jejuni/coli Isolates showed the resistance to one antimicrobial agent. Meanwhile, the multiple resistance ratio for more than 4 lines of antimicrobial agent was 19.2% of E. coli (38/197 strains), 11.9% of S. aureus (5/42 strains), 15.4% of C. jejuni/coli (2/13 strains) and 6.2% of E. faecium/faecalis (14/223 strains). The antimicrobial resistance ratio of bacteria isolated from the cattle farm showed lower than that of bacteria isolated from the pig or chicken farm, which might be related to the quantify of antimicrobial agents consumed. And one strain of vancomycin resistant E..faecium (VREF) were isolated from the excrement of chicken and stream, respectively. Generally, the ratio of VREF collected in animal farm environments is lower than that of VREF collected in medical environment.

• Korean Journal of Veterinary Research
• /
• v.17 no.2
• /
• pp.73-78
• /
• 1977

The distribution of coliform population and drug-resistant coliforms in Shinchun water during April to August in 1976 and R factors in resistant strains were studied. The mean coliform population in the stream water was 361 organisms per 0.1ml and 53.5% of total coliforms were fecal coliforms. Thritynine and a half percent of total coliforms were streptomycin (SM) resistant to one or more of following antibiotics; tetracycline (TC), chloramphenicol (CM), ampicillin (AP) and kanamycin (KM). The most frequent resistant pattern was triple resistance to SM, TC and AP (23.8%) and followed by quadruple one to SM, TC, CM and AP (17.5%). About 87 percent strains carried R factors which were transferable by conjugation to E. coli ML 1410 or S. typhimurium LT 2.

• Korean Journal of Veterinary Research
• /
• v.23 no.2
• /
• pp.205-209
• /
• 1983

Some investigations on chronic mastitis in dairy cattle in Kyungnam Province during the year 1982 were conducted with the special reference to the causative agents and their drug resistance. Milk samples from 46 isolated cases of chronic mastitis cattle were investigated bacteriologically and the organisms recovered were examined for their drug susceptibility against the major antibiotics used in this country by the use of disk diffusion susceptibility test. Four major causative agents involved in chronic mastitis were in order of prevalence Staphylococcus aureus (32.6%), Escherichia coli (28.3%), Streptococcus agalactiae (8.7%) and Candida albicans (8.7%). Staph. epidermidis, Streptococcus uberis, Klebsiella pneumoniae and Candida subtropicalis were found to be one of the minor agents. The majority of staphylococcal isolates were highly resistant to the most of antibiotics employed while 8% of them were resistant to gentamicin and 32% to chloramphenicol. The percentages of staphylococcal cultures resistant to penicillin, lincomycin. streptomycin, methicillin, oleandomycin, tetracycline, cephalothin, ampicillin and erythromycin were 100%, 96%, 96%, 92%, 84%, 84%, 80%, 76%, and 64% respectively. Streptococcal isolates were also highly resistant to the majority of the drugs used although 85.7% of them were susceptible to gentamicin. All Escherichia coli isolates were found to be resistant to erythromycin, lincomycin and penicillin while the majority of them were resistant to ampicillin (92.9%), carbenicillin (85.7%), oleandomycin (85.7%), streptomycin(85.7%), kanamycin (78.6%), methicillin (78.6%) and tetracycline (71.4%). The percentages of E. coli cultures resistant to gentamicin, nitrofurantoin, cephalothin and chloramphenicol were 21.4%, 21.4%, 35.7% and 50.0% respectively.

• Korean Journal of Veterinary Research
• /
• v.20 no.2
• /
• pp.85-92
• /
• 1980

The antimicrobial drug susceptibility of 439 isolates of animal pathogens recovered from various clinical cases during 1978-79 has been investigated by the use of disk diffusion technique. The majority of 308 strains of Eschericihia coli were highly resistant to bacitracin, erythromycin, penicillin, streptomycin and tetracyclinon while only 0.3 per cent of them were resistant to gentamicin and 3.2 per cent to colistin. The percentages of strains resistant to ampicillin, carbenicillin, cephalothin, chloramphenicol and neomycin were 30.5%, 24.7%, 11:4%, 28.2% and 26.2% and repectively. However, none of E. coli cultures of ovine origin were resistant to ampicillin, carbenicillin, chloramphenicol, colistin, gentamicin, kanamycin, and neomycin. A total of 39 patterns of multipe drug1 resistance of 308 strains E. coli against 9 drugs in general use such as ampicillin, cephalothin, chloramphenicol, colistin, gentamicin, kanamycin, neomycin, streptomycin and tetracycline were observed and the most common multiple resistance patterns were SM, TC pattern (20.5%) and AM, CP, KM, NM, SM, TC pattern (9.7%). None of the 43 cultures of salmonella organism from pigs and chickens were resistant to ampicillin, carbenicillin, cephalothin, colistin, gentamicin and kanamycin; and the majority of the cultures were susceptible to chloramphenicol (90.0%), neomycin (97.7%) and tetracycline (93.0%). All the cultures were found to be resistant to bacitracin and penicillin and the rate of resistant strains to erythromycin and s treptomycin being 79.1% and 41.9% respectively. It was found that the majority of 63 cultures of staphylococcal isolates were resistant to lincomycin, penicillin, streptomycin and tetracycline. The percentages of 63 staphylococcal isolates susceptible to gentamicin, nitrofurantoin, cephalothin, ampicillin, methicillin, bacitracin and chloramphenicol were 98.4%, 98.4%, 95.2%, 93.7%, 93.7%, 92.1% and 92.1% respectively. The 25 cultures of streptococcal isolates were resistant in order of prevalence to streptomycin(88.0%), kanamycin(68.0%), gentamicin (44.0%), tetracycline (44.0%) and methicillin (40.0%) wihle the majority of them were sensitive to ampicillin, bacitracin, chloramphenicol and penicillin.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.1
• /
• pp.25-33
• /
• 2012

The association of verotoxic E. coli and Acinetobacter spp. with various antibiotic-resistant, diarrhogenic, and nosocomial infections has been a cause for concern worldwide. E. coli and A. haemolyticus isolated on a number of selective media were screened for virulence factors, antibiotic resistance, and transformation of resistance genes. Out of 69 E. coli isolates obtained, 25 (35.23%), 14 (20.30%), and 28 (40.58%) were positive for Vtx1&2, Vtx1, and Vtx2, respectively, 49 (71.015%) for extendedspectrum beta-lactamases (ESBLs), 34 (49.28%) for serum resistance, 57 (82.61%) for cell surface hydrophobicity, 48 (69.57%) for gelatinase production, and 37 (53.62%) for hemolysin production. For the 14 A. haemolyticus isolates, only 2 (14.29%) in each case from all the samples investigated were positive for Vtx1, Vtx2 and Vtx1&2 respectively, 8 (57.14%) for ESBLs, 7 (50.00%) for serum resistance, 11 (78.57%) for cell surface hydrophobicity, 4 (28.57%) for gelatinase production, and 8 (57.14%) for hemolysin production. Although transformation occurred among the E. coli and Acinetobacter isolates (transformation frequency: $13.3{\times}10^{-7}-53.4^{-7}$), there was poor curing of the plasmid genes, a confirmation of the presence of stable antibiotic-resistant genes (DNA concentration between 42.7 and 123.8 ${\mu}g$) and intragenetic transfer of multidrug-resistant genes among the isolates. The isolates were potentially virulent and contained potentially transferable antibiotic resistance genes. Detection of virulence factors, antibiotic resistance genes, and transformation among these isolates is a very significant outcome that will influence approaches to proactive preventive and control measures and future investigations. However, continued surveillance for drug resistance among these bacteria and further investigation of the mechanism of action of their virulence factors are a necessity.

• Food Science and Biotechnology
• /
• v.15 no.3
• /
• pp.339-340
• /
• 2006

The pattern of drug resistance and incidence of R-factors were studied in Shigella sonnei as food-borne pathogen strains isolated from chicken meat in Iran. In this study we examined for transferring R-factors of S. sonnei to sensitive Escherichia coli $k_{12}{\bar{F}}(\lambda)$. The results showed that 19 out of 57 strains (33.3%) were resistant to one or more drugs and multiple drug resistance was more common than single drug resistance. The most predominant pattern of resistance observed was Tetracycline (Tc), Chloramphenicol (Cm), Streptomycin (Sm), and Sulfonamide (Su). 100% of the strains from the Caspian littoral transferred at least a part of their resistance pattern to sensitive E.coli $k_{12}{\bar{F}}(\lambda)$.

• Natural Product Sciences
• /
• v.17 no.2
• /
• pp.160-164
• /
• 2011

The purpose of this investigation was to extract the bioactive agents from Alpinia officinarum Hance. The methanol with ethylacetate extracts alone and combined were examined for their activities against VRE (vancomycin-resistant enterococci) and pathogenic yeast in vitro. The incidence of infections caused by VRE and other pathogenic microorganisms and the importance of using novel synergistic drug combinations has become important. Previously, we reported the antimicrobial effects of the butanol extract from Lonicera japonica and have evaluated combinations of solvent extracts, with a focus on the MeOH and EtOAc extracts from A. officinarum. In the present study, enhanced inhibitory effects were achieved by employing a combination of the two solvent extracts. The MeOH and EtOAc combination was especially effective against four VRE strains: E. faecalis (K-10-22), E. faecaium (K-11-212), E. faecalis (K-10-57) and E. faecalis (K-10-361) with MIC values of 12.5, 12.5, 6.25 and 25 ${\mu}g/ml$, respectively. Thus, the combination was more effective than other antibiotics such as kanamycin, gentamicin or tetracycline against bacteria including E. coli, Staphylococcus aureus, and Micrococcus luteus. In addition, the combination was effective against yeasts such as Candida albicans, Candida tropicalis and Cryptococcus neoformans.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.7
• /
• pp.1007-1014
• /
• 2015

Plectasin, the first defensin extracted from a fungus (the saprophytic ascomycete Pseudoplectania nigrella), is attractive as a prospective antimicrobial agent. The purpose of this study was to establish a bacterium-based production system and evaluate the antimicrobial activity of the resulting plectasin. A gene encoding plectasin, with the codon preference of Escherichia coli, was optimized based on its amino acid sequence, synthesized using genesplicing with overlap extension PCR, and inserted into the expression vector pGEX-4T-1. The fusion protein was expressed in the soluble fraction of E. coli and purified using glutathione Stransferase affinity chromatography. Plectasin was cleaved from the fusion protein with thrombin and purified by ultrafiltration. The purified plectasin showed strong, concentrationdependent antimicrobial activity against gram-positive bacteria, including antibiotic-resistant bacteria, especially penicillin-resistant Enterococcus faecium. This antimicrobial activity was equal to chemically synthesized plectasin and was maintained over a wide range of pH and temperatures. This soluble recombinant expression system in E. coli is effective for producing plectasin at a relatively lower cost, and higher purity and efficiency than prior systems, and might provide a foundation for developing a large-scale production system. Overall, plectasin shows potential as a novel, high-performance, and safe antibiotic for the treatment of refractory diseases caused by drug-resistant bacterial strains.

• Korean Journal of Veterinary Service
• /
• v.15 no.1
• /
• pp.81-88
• /
• 1992

This study was conducted to determine the microorganisms inhabitating in sow genital organs and their anti-microbial drug susceptibility During the period between February, 1991 and November 1991, 128 sow genital organs were sampled at six abattoirs. Gross pathological examination and bacterial isolation and identification were performed from the genital organ. In addition, antimicrobial drug susceptibility for the major organisms isolated were examined. 1. Among the bateria isolated from normal genital organs, E. coli(30.7%) Stahylococcus spp.(29.4%), Corynebarterium pyogenes(C. pyogenes) (14.7%), Streptococcus spp.(13.3%) were most freqently isolated, whereas the genera of Klebsiella, Actinobacillus, and Serratia were detected less freqently. 2. Among the bacteria isolated from abnormal genital organs, C. pyogenes,(37.7%), Stahylococcus spp.(30.2%), Proteus spp. (26.4%) , Pasteurella spp. (18.9%) , Steptococcus spp. (9.4%) were most freqently isolated whereas the genera of Pseudomonas, Serratia and Klebsiella were detected less freqently. 3. From sow genital organs showing lesion of endometritis and purulent endometritis C. pyogenes were most freqently isolated, the isolation rate being 67.7％ and followed by Stahylococcus spp., E. coli, Proteus spp., Steptococcus spp. and Pasteurella spp. in the order. 4. Antimicrobial drug susceptibility of the major organisms showed that all the isolates were susceptible to cephalothin, ampicillin, chloramphenicol and sulfamethoxazole / trimethoprim, but resistant to penicillin and streptomycin.

• Journal of Veterinary Science
• /
• v.22 no.5
• /
• pp.68.1-68.15
• /
• 2021

Background: Colistin and carbapenem-resistant bacteria have emerged and become a serious public health concern, but their epidemiological data is still limited. Objectives: This study examined colistin and carbapenem resistance in Escherichia coli and Salmonella from pigs, pig carcasses, and pork in Thailand, Lao PDR, and Cambodia border provinces. Methods: The phenotypic and genotypic resistance to colistin and meropenem was determined in E. coli and Salmonella obtained from pigs, pig carcasses, and pork (n = 1,619). A conjugative experiment was performed in all isolates carrying the mcr gene (s) (n = 68). The plasmid replicon type was determined in the isolates carrying a conjugative plasmid with mcr by PCR-based replicon typing (n = 7). The genetic relatedness of mcr-positive Salmonella (n = 11) was investigated by multi-locus sequence typing. Results: Colistin resistance was more common in E. coli (8%) than Salmonella (1%). The highest resistance rate was found in E. coli (17.8%) and Salmonella (1.7%) from Cambodia. Colistin-resistance genes, mcr-1, mcr-3, and mcr-5, were identified, of which mcr-1 and mcr-3 were predominant in E. coli (5.8%) and Salmonella (1.7%), respectively. The mcr-5 gene was observed in E. coli from pork in Cambodia. Two colistin-susceptible pig isolates from Thailand carried both mcr-1 and mcr-3. Seven E. coli and Salmonella isolates contained mcr-1 or mcr-3 associated with the IncF and IncI plasmids. The mcr-positive Salmonella from Thailand and Cambodia were categorized into two clusters with 94%-97% similarity. None of these clusters was meropenem resistant. Conclusions: Colistin-resistant E. coli and Salmonella were distributed in pigs, pig carcasses, and pork in the border areas. Undivided-One Health collaboration is needed to address the issue.