• Journal of Environmental Health Sciences
• /
• v.19 no.1
• /
• pp.71-76
• /
• 1993

Nasal carrige of Staphylococcus was studied in relation to its significance as a source of the Staphylococci that caused hospital-acquired infection. Due to the trend of the increasing r esistance of S. aureus to many antimicrobial agents, it is necessary to study the sensitivity to antibiotics of this infectious microorganisms. 50 persons from general hospital and 50 college students were the object of this study. The following results were obtained 3 0 Strains of S. aureus were isolated. The rate of S. aureus nasal carrying were 26% in college students and 34% in hospital personnel. S. aureus which showed resistance to penicillin were 90%, tetracyclin 43%, erythromycin 37% and oxacillin 17%. The number of penicillin resistance of S. aureus were 11 (84%) in college students and 16 (94%) in hospital personnel. The number of strains of penicillin resistant S. aureus which produced 13-1actamase were 9 (82%) in college student and 14 (88%) in hospital personnel. Methicillin-resistant S. aureus (MRSA) which showed resistance to erythromycin and penicillin G were 100%, tetracyline, cephalothin and clindamycin were over 40% respectively, gentamicin 20%, SAM 20% and chloramphenicol 0%.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.6
• /
• pp.918-926
• /
• 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 Fisheries and Aquatic Sciences
• /
• v.51 no.1
• /
• pp.1-7
• /
• 2018

We investigated patterns of antimicrobial resistance in Escherichia coli isolated from the water discharged from inland pollution sources in the Hansan-Geojeman and Jaranman-Saryangdo areas of Korea. A total of 217 strains of E. coli were isolated from 23 point-sources. These strains were tested for their susceptibility to 16 antimicrobial agents used in Korea for medical or veterinary therapy. The highest level of antibiotic resistance among the isolated strains was to tetracycline 10.6%, followed by ampicillin (3.2%), nalidixic acid (2.8%), rifampin (1.8%), trimethoprim (1.8%), trimethoprim/sulfamethoxazole (1.8%), chloramphenicol (1.4%), streptomycin (1.4%), cephalothin (0.5%) and gentamicin (0.5%). Resistance to at least one antimicrobial agent was present in 17.1% of the E. coli isolates. Only four of the isolated strains of E. coli showed multiple antibiotic resistance, which is defined as resistance to more than four antibiotics.

• Microbiology and Biotechnology Letters
• /
• v.48 no.2
• /
• pp.230-235
• /
• 2020

The global evolution of antibiotic resistance has threatened the efficacy of available treatment options with ravaging impacts observed in developing countries. As a result, investigations into the prevalence of antibiotic resistance and the role of plasmids are crucial. In this study, we investigated the presence and distribution of bla_TEM and gyrA genes, plasmid profiles, and the antimicrobial susceptibility pattern of Salmonella strains isolated from raw meat and stool sources across Niger State, Nigeria. Ninety-eight samples, comprising 72 raw meat and 26 stool samples, were screened for Salmonella spp. The antimicrobial susceptibility of Salmonella isolates to 10 commonly used antimicrobial agents was determined using the KirbyBauer disc diffusion method. Isolates were further analyzed for plasmids, in addition to PCR amplification of beta-lactamase (bla_TEM) and gyrA genes. A total of 31 Salmonella spp. were isolated, with 22 from raw meat (70.97%) and 9 from stool (29.03%). Salmonella spp. with multiple resistance patterns to ceftazidime, cefuroxime, ceftriaxone, erythromycin, ampicillin, cloxacillin, and gentamicin were detected. Ofloxacin and ciprofloxacin were found to be the most effective among the antibiotics tested, with 67.7% and 93.5% susceptible isolates, respectively. Nine (29.03%) isolates harbored plasmids with molecular sizes ranging between 6557 bp and 23137 bp. PCR amplification of gyrA was detected in 1 (3.23%) of the 31 isolates while 28 isolates (90.32%) were positive for bla_TEM. This study shows the incidence of antibiotic resistance in Salmonella isolates and the possible role of plasmids; it also highlights the prevalence of ampicillin resistance in this local population.

• Korean Journal of Veterinary Service
• /
• v.40 no.3
• /
• pp.193-200
• /
• 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
• /
• v.34 no.3
• /
• pp.217-226
• /
• 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
• /
• v.51 no.4
• /
• pp.432-440
• /
• 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.

• Current Research on Agriculture and Life Sciences
• /
• v.2
• /
• pp.115-121
• /
• 1984

Some investigations on chronic mastitis in dairy cattle in Taegu-Kyungpook Provinces from the beginning of October, 1984 till the end of August, 1985 were conducted with the particular regard to the causative agents and their drug susceptibility. Milk samples from 83 isolated cases of chronic mastitis cattle were investigated bacteriologically and the causative organisms recovered were examined for their antibiotic susceptibility by using disc diffusion susceptibility technique against the major antibiotics of current veterinary use. Major causative agents involved in chronic mastitis in Taegu-Kyungpook Provinces were in order of prevalence Staphylococcus spp. (48.2 %), Escherichia coli (18.1 %), Candida spp. (10.8 %) and Corynebacterium spp. (8.4 %), Streptococcus agalactiae (3.6 %), Bacillus cereus (3.6 %) and Pseudomonas aeruginosa (2.4 %) were found to be one of the minor agents. The majority of staphylococcal isolates and E. coli were highly resistant to the most antibiotics tested. The percentages of staphylococcal cultures resistant to penicillin, methicillin, lincomycin, novobiocin, ampicillin and tetracycline were 87.2 %, 78.7 %, 68.1 %, 61.7% and 57.4 %, respectively, while the majority of them were susceptible to gentamicin(78.7 %), cephalothin(76.6 %) and chloramphenicol (74.5%). E. coli isolates were found to be highly resistant to streptomycin, cephalothin, tetracycline and ampicillin while the majority of them were susceptible to colistin (83.3 %), gentamicin (77.8 %) and chloramphenicol (66.7 %). Corynebacterium spp. were susceptible to ampicillin, chloramphenicol, erythromycin, gentamicin, oleandomycin and tetracycline although they showed resistance to novobiocin and penicillin. Two cultures of Pseudomonas aeruginosa recovered from mastitis milk were highly resistant to the antibiotics employed in the present study.

• Korean Journal of Clinical Laboratory Science
• /
• v.52 no.2
• /
• pp.136-142
• /
• 2020

The antimicrobial resistance rate in bacteria has increased over the last several decades. The transfer of antimicrobial resistant determinants on mobile genetic elements could cause the accelerated emergence and spread of multidrug resistant bacteria. This study investigated the aminoglycoside resistance determinants transferred by mobile genetic elements in a total of 33 aminoglycoside non-susceptible E. coli isolated from clinical specimens in Chungcheong province. 16S ribosomal RNA methyl-transferases (RMTases) and aminoglycoside-modifying enzyme (AME) genes were detected via PCR and DNA sequencing. The most common AME genes were aac(3')-II gene (54.5%), followed by aph(3')-Ia (18.2%) and aac(6')-Ib (15.2%). None of the evaluated RMTase genes were detected in the 33 isolates. Seventeen of the 18 isolates harboring aac(3')-II gene were resistant to gentamicin, and 16 of them were resistant to tobramycin. The 5 isolates harboring aac(6')-Ib gene were all resistant to tobramycin. In this study, we confirmed that one of the important mechanisms of aminoglycoside resistance in E. coli isolated from human is the acquisition of AME genes. Continuing investigations of antimicrobial resistant determinants in bacteria isolated from human may be required to prevent dissemination of antimicrobial resistant bacteria.

• Journal of Life Science
• /
• v.10 no.3
• /
• pp.262-272
• /
• 2000

As a part of investigation for basic epidemiology of diarrheogenic disease, we attempted isolation of Escherichia coli from patients with diarrhea. Seven hundred and twenty-one strains of E. coli were isolated from 1,239 patients with diarrhea. Seasonal distribution of patient with diarrhea was shown the most high at August (18.2%). Age group distribution of patient was shown the most high at children (54.6%, 2 to 10 years old). The serotypes of 721 E. coli isolates were in order of serotype O44 (16.8%), O153 (8.6%), O1 (7.5%), O166(5.7%), O8 and O86a (4.7%), and O125 (4.6%). The supernates cultured 36 strains among 721 E. coli isolates were indicated cytotoxicity against monolayered Vero cells. All of the isolates were susceptible to amikacin. The isolates were resistant in order of novobiocin (99.0%), moxalactam (97.1%), carbenicillin (96.1%), tetracycline (90.4%), ampicillin (85.9%), gentamicin (84.0%), streptomycin (78.4%), cephalothin (46.6%) and polymyxin B (4.2%). In the antibiotic resistant patterns, 125 kinds of multiple resistance patterns of E. coli isolates were detected. The highest resistant pattern was ampicillin-carbenicillin-chloramphenicol-cephalothin-erythro-mycin- gentamicin-moxalactam-novobiocin-penicillin G-streptomycin-tobramycin-tetracycline-tri methoprim type (24.3%).