• Korean Journal of Veterinary Service
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• v.32 no.2
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• pp.155-163
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• 2009

Fowl typhoid (FT) is a septicemic disease caused by Salmonella Gallinarum. The purpose of this study was to investigate the antimicrobial resistance and pulsed-field gel electrophoresis (PFGE) patterns of S. Gallinarum isolated from chicken. During 1999 to 2004, there was isolated a total of 100 strains in liver and spleen. The biochemical characteristics of S. Gallinarum isolates was nonmotile, no production of H$_2$S, glucose gas, non-fermented rhamnose, indole-negative, fermentation of dulcitol, mannitol, maltose, and ornithine decarboxylase. At antimicrobial susceptibility, all of isolates were susceptible to amoxicillin/clavulanic acid, amikacin, neomycin, kanamycin, norfloxacin and enrofloxacin. One hundred isolates were divided into 54 resistant patterns and 37 strains was 6-multi drug resistance. PFGE of Xba I restriction fragments of S. Gallinarum isolates was 20 patterns.

• Journal of Microbiology and Biotechnology
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• v.20 no.10
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• pp.1446-1449
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• 2010

A total of 1,444 coagulase-negative staphylococci (CNS) isolates from bovine mastitic milk samples collected during 2003-2008 in Korea were identified to the species level. Of 14 species identified, S. simulans, S. haemolyticus, and S. sciuri accounted for over 60% of the isolates. All the CNS isolates were tested for susceptibility to eight antimicrobials commonly used in dairy cattle. With a few exceptions, similar resistance patterns were observed among the CNS species: penicillin and ampicillin showed the lowest activity, whereas amikacin, cephalothin, and gentamicin were highly effective. About 39% (557/1,444) of the CNS isolates were pan-susceptible, whereas 12% (175/1,444) showed resistance to four or more antimicrobials tested.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.918-926
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• 2021

We isolated 28 Vibrio vulnificus strains from seawater and fisheries and investigated the positive rate of eight virulence genes. Additionally, we evaluated the susceptibility of these strains to 25 antimicrobials. The positive rates of fur, vvhA, tcp, rtxA, vcgC, viuB, vvp, and acfA were 100, 92.9, 92.9, 67.9, 64.3, 25.0, 14.3, and 7.1%, respectively. A disk diffusion susceptibility test revealed that, all the investigated strains had the highest resistance to amoxicillin and oxacillin, followed by that to streptomycin (96.4%), cefoxitin (92.9%), clindamycin (82.1%), amikacin (67.9%), vancomycin (46.4%), nalidixic acid (7.1%), penicillin G (7.1%), and ampicillin (3.6%). Moreover, they were susceptible to 10 other antimicrobials, including cefotaxime, chloramphenicol, erythromycin, gentamicin, and rifampicin. Notably, amoxicillin, oxacillin, and streptomycin had average minimum inhibitory concentrations of 132.6, 603.4, and 23.1 ㎍/mL against V. vulnificus, respectively. These observations provide new insights regarding the necessity for sanitation of commercial fisheries and can potentially, help reduce the risk posed by fisheries contaminated with bacteria resistant to antimicrobials.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.209-216
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• 2021

This study was aimed to investigate occurrence and the antimicrobial resistance of Escherichia coli isolates obtained from the feces of wild birds in Daegu. In total, 98 E. coli isolates (17.9%) were obtained from 547 fecal samples of wild birds. The E. coli carried by the birds showed a relatively high rate of antimicrobial resistance to tetracycline (27.6%) and ampicillin (21.4%). Drug resistance of the isolates to the others (penicillins, cephems, carbapenems, aminoglycosides, quinolones, sulfonamides and phenicols) resulted in the rates less than 20%, and all isolates were susceptible to imipenem, ciprofloxacin, cefotetan, and amikacin. Approximately, 45% E. coli among the isolates were resistant to one or more drugs tested. The higher rate of tetracycline resistance led us to determine the prevalence of the tet genes (tetA, tetB, tetC, tetD and tetE) in the tetracycline-resistant E. coli isolates by using PCR. All isolates of the tetracycline-resistant E. coli contained at least one or more of these tet genes examined. The most prevalent one was tetA (59.3%), and followed by tetB (7.4%) when tested with the selected 5 tet genes. Except tetA and tetB, however, the remaining tet genes (tetC, tetD, and tetE) tested were not found in this study. Nine isolates among the tetracycline-resistant E. coli contained the two (tetA and tetB) determinants of tetracycline resistance, simultaneously.

• Korean Journal of Veterinary Service
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• v.40 no.3
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• pp.193-200
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• 2017

This study was carried out to investigate the antimicrobial resistance profiles and resistance genes in 62 Escherichia coli isolated from dogs and cats hospitalized at animal hospitals in Daegu. E. coli isolates showed high resistance to nalidixic acid (46.8%) and ampicillin (45.2%). Resistance to the other antimicrobial agents was less than 30%, and no resistant isolates were detected for imipenem and amikacin. Of the 28 ampicillin-resistant isolates, TEM and CTX-M genes were detected in 16 (57.1%) and 11 (39.3%), respectively. The aadA gene was found in 4 (26.7%) of 15 gentamicin-resistant isolates, and strA-strB gene was found in 10 (66.7%) isolates. The sul I and sul II genes were detected in 11 (61.1%) and 14 (77.8%) of 18 trimethoprim/sulfamethoxazole-resistant isolates, and tetB gene in 9 (81.8%) of 11 minocycline-resistant isolates, and cmlA gene in 2 (22.2%) of 8 chloramphenicol-resistant isolates. The qnrB and qnrS genes were found in 3 (10.3%) and 1 (3.4%) of 28 nalidixic acid-resistant isolates, respectively. Whereas, none of the SHV, CMY-2, tetA, dfr Ia and dfr VII, and qnrA genes were found. Our results show a wide variety of resistance genes in E. coli isolates from dogs and cats. This study also represents the first report of qnrB and qnrS gene producing E. coli isolates from dogs in republic of Korea.

• Korean Journal of Veterinary Service
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• v.34 no.3
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• pp.217-226
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• 2011

Salmonella spp. is of increasing public health concern as causative pathogens of food poisoning. The aim of this study was to investigate the serotypes and antimicrobial resistance pattern of Salmonella spp. isolated from duck farms in Daegu-Gyeongbuk province. Also, S. Enteritidis and S. Typhimurium isolates were further examined for plasmid analysis, phage typing and pulsed-field gel electrophoresis (PFGE). A total of 34 Salmonella spp. (16.4%) were isolated from duck farms and ten serotypes were identified. The predominant serotypes were S. Typhimurium (23.5%) S. Fyris (17.6%) and S. Haardt (11.8%), S. Agona and S. Enteritidis (respectively 8.8%). Of 34 Salmonella isolates, 15 (44.1%) isolates were resistant to at least one antimicrobial agent and multiple resistance (resistance to more than 4 drugs) was observed in 9 strains (26.5%). The high resistance was found to streptomycin (32.4%), tetracycline (29.4%), ampicillin, kanamycin and nalidixic acid (respectively, 26.5%), all Salmonella isolates were susceptible to cefoxitin, cefotaxime, gentamicin, amikacin and ciprofloxacin. All S. Enteritidis and S. Typhimurium isolates were found to contain only one plasmid (ca. 54 or 55kb, respectively). Among the S. Enteritidis isolates, two phage types were found, PT32a and PT1c, respectively, one isolates did not react with any of the phages used. Whereas, all S. Typhimurium isolates were RDNC (reacts but does not conform). PFGE showed to be a useful typing method better than plasmid analysis and phage typing for discrimination of isolates especially, S. Typhimurium isolates. Our results indicated that the serotypes of Salmonella isolates are widely distributed in duck farms, further epidemiological studies should be carried out.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.432-440
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• 2023

Irrational and injudicious use of antibiotics, easy availability of them as over-the-counter drugs in economically developing countries, and unavailability of regulatory policies governing antimicrobial use in agriculture, animals, and humans, has led to the development of multi-drug resistance (MDR) bacteria. The use of medicinal plants can be considered as an alternative, with a consequent impact on microbial resistance. We tested extracts of Piper longum fruits as new natural products as agents for reversing the resistance to antibiotics. Six crude extracts of P. longum fruits were utilized against a clinical isolate of multidrug-resistant Staphylococcus aureus.The antibiotic susceptibility testing disc method was used in the antibiotic resistance reversal analysis. Apart from cefoxitin and erythromycin, all other antibiotics used (lincosamides [clindamycin], quinolones [levofloxacin and ciprofloxacin], and aminoglycosides [amikacin and gentamicin]) were enhanced by P. longum extracts. The extracts that showed the greatest synergy with the antibiotics were EAPL (ethyl acetate [extract of] P. longum), n-BPL (n-butanol [extract of] P. longum), and MPL (methanolic [extract of] P. longum The results of this study suggest that P. longum extracts have the ability to increase the effectiveness of different classes of antibiotics and reverse their resistance. However, future studies are needed to elucidate the molecular mechanisms behind the synergy between antibiotic and phytocompound(s) and identify the active biomolecules of P. longum responsible for the synergy in S. aureus.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.327-334
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• 2016

Recently, antimicrobial resistance of pathogenic bacteria has been increasing due to excessive use of antimicrobial agents in both humans and livestock. PCR amplification and nucleotide sequence analyses were conducted to investigate16S ribosomal RNA methyltransferase (RMTase) genes and integrons in P. mirabilis strains isolated from clinical specimens and chickens in an area of the Chungcheong providence. In addition, clonality analysis of P. mirabilis strains was performed using a repetitive extragenic palindromic sequence-based PCR (REP-PCR) method. Of the total 38 P. mirabilis isolates, 7 (18.4%) strains were isolated from clinical specimens contained in the RMTase genes and showed resistance to amikacin, tobramycin, and gentamicin. A total of 23 (60.5%) isolates carried class 1 integrons, but no isolates in our study harbored class 2 and class 3 integrons. Class 1 integrons detected in our study harbored genes encoding resistance to aminoglycosides (aadA2, aadA5, aadA7, and aacCA5), ${\beta}$-lactams ($bla_{PSE}$), erythromycin (ereA), lincosamides (linF), and trimethoprim (dfrA12, dfrA17, and dfrA32). We confirmed that the RMTase genes had spread among only the P. mirabilis isolates from clinical specimens, but class 1 integrons had widely disseminated among P. mirabilis isolates from clinical specimens and chickens. In addition, identical REP-PCR banding patterns were evidenced in only P. mirabilis isolates from chickens. Our results suggest the horizontal spreading of P. mirabilis isolates in the chicken farm. To prevent further spreading of antimicrobial resistant genes among P. mirabilis isolates, monitoring and clinical policing will be required.

• Journal of Animal Science and Technology
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• v.50 no.6
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• pp.793-798
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• 2008

The semen collection process in the porcine is far from being a sterile procedure. Consequently, porcine ejaculates commonly contain bacterial contaminants. The aim of this study is to identify the bacteria in porcine semen and to find the antibiotics resistance of bacteria. Twelve porcine originating from four AI center were used to collect semen. Bacteria were identified by automated instrument for rapid organism identification system and bacterial sensitivities of 8 antibiotics were tested. The Bacterial contaminants of Staphylococcus genus(37.8%), Proteus genus(7.0%), Bacillus genus (6.1%), Pasteulla genus(5.7%), Acinetobacte genus(5.2%), Serratia genus(4.3%) and others(33.9%) were frequently isolated. However, amikacin showed higher antibiotic sensitivity than other antibiotics. General sanitation protocols can contribute partly to inhibit the bacterial contamination, with monitoring boar housing, semen collection areas and the extended semen. But, proper selection of preservative antibiotics by microbial sensitivities can minimize the influence of bacteria.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.1
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• pp.81-87
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• 2021

Olive flounders which were cultured in commercial fish farm showed abnormal swimming behavior in November 2020. Then, gradual mortality was observed in the fish farm. During the diagnosis, bacterial strain KNCFKW-PN1 was isolated from the kidney of the dead fish. Based on the sequence of gyrase B subunit gene, KNCFKW-PN1 was proved to be Pseudoalteromonas nigrifaciens, showing 99.59% nucleotide identity with that of P. nigrifaciens LMG 2227^T. According to the result of antibiotic susceptibility test, P. nigrifaciens KNCFKW-PN1 showed intermediate resistance to ciprofloxacin, and was resistant to ampicillin, cefepime, cefotaxime, ceftazidime, and amikacin. This is the first report of the isolation of multiple-antibiotic-resistant P. nigrifaciens from olive flounder.