• Food Science of Animal Resources
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• v.33 no.1
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• pp.133-138
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• 2013

In this study, a total of 256 samples of retail raw meats (beef, pork and chicken) and sashimi were investigated for the presence of Enterococcus faecalis and Enterococcus faecium. We isolated a total of 117 E. faecalis and E. faecium from the samples, with contamination rates ranging from 18.8% for sashimi samples to 68.8% of chicken samples. E. faecalis was the predominant species recovered from all of the retail raw meats beef (42.2%), pork (42.2%), chicken (65.6%) and sashimi (12.5%). Among 117 isolates, 61 isolates (52.1%) were resistant to tetracycline, 32 isolates (27.4%) were resistant to erythromycin, 23 isolates (19.7%) were resistant to chloramphenicol, 16 isolates (13.7%) were resistant to ripampin, 10 isolates (8.5%) were resistant to gentamycin, 9 isolates (7.7%) were resistant to ciprofloxacin and 1 isolate (0.9%) was resistant to ampicillin and penicillin G. No resistance to amoxicillin + clavulanic acid and vancomycin was observed. Although no strain was resistant to vancomycin, the vanB gene was observed in 9 of 117 of Enterococcus (7.7%) demonstrating potential risk of vancomycin-resistant Enterococcus (VRE). Our results indicate that E. faecalis and E. faecium were highly prevalent in retail raw meats, but most strains were sensitive to tested antibiotics.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.295-303
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• 2006

To provide microbial information for the safety of agricultural production, the presence of enterotoxin genes and antibiotic susceptibility of 14 isolated Staphylococcus aureus (11.7%) strains were investigated using PCR-based methods and disk diffusion method, respectively. Among enterotoxin-encoding genes, sea was detected from two isolates (14.3%), sea and sed genes were co-detected from three isolates (21.4%), and sea, sed, and see genes in seven isolates (50.0%), whereas seb, sec, and tsst were not detected in any isolate. Nine (64.3%), eight (57.1%), six (42.9%), two (14.3%), and one (7.2%) isolates were resistant to penicillin, novobiocin, amphicillin, erythromycin and oxacillin, and doxycycline and kanamycin, respectively. Methicilline-resistant S. aureus was found in roller of B farm and in hydroponic solution of D farm.

• Journal of Food Hygiene and Safety
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• v.36 no.6
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• pp.520-527
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• 2021

In this study, toxin gene and antibiotic resistance of food poisoning strains isolated from indoor air in the cafeteria were analyzed to prevent food poisoning. Staphylococcus aureus (16 strains) and Bacillus cereus (37 strains) isolated from indoor air in child care center were tested. The toxin genes of S. aureus and B. cereus were detected by PCR assay. The antimicrobial susceptibility test followed the disc diffusion method described by the Clinical and Laboratory Standard Institute. The seg and sei toxin genes were detected in 11 of 16 S. aureus strains (68.6%). The nheA and nheB toxin genes were detected in 37 B. cereus strains. In this study, a total of 12 toxin gene patterns of B. cereus were found, among which the nheA-nheB-nheC toxin gene was found to be the most frequent pattern. The result of the antimicrobial susceptibility test of S. aureus revealed 93.8% and 87.5% resistance to ampicillin and penicillin antibiotics, but methicillin resistance S. aureus and vancomycin resistance S. aureus were not detected. All 37 B. cereus tested in this study were resistant to ampicillin and penicillin antibiotics. Based on the result of this study, it was judged that regular ventilation and air quality management were necessary to prevent food poisoning caused by S. aureus and B. cereus contaminated in the indoor air of child care centers.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.90-94
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• 2013

A new Bacillus strain designated as MP56 producing antimicrobial substance has been isolated from the mud flat of Korea. The strain MP56 was found to exhibit broad spectrum of antimicrobial activity against Gram-positive pathogenic microorganisms and MDR (multi drug resistant) strains. The 16S rRNA sequence revealed that the MP56 was closely related to Bacillus subtilis with 99.93% homology. The optimal medium composition for production of antimicrobial substance in the B. subtilis MP56 were 1% mannitol, 1% oat meal, 0.01% $CaCl_2$. Antimicrobial activity of the culture broth against different pathogenic strains was assessed using the antimicrobial spectrum. The result suggests that Bacillus strain MP56 produces high quality antimicrobial substance that might be very useful to control varieties of pathogenic microbial growth.

• Microbiology and Biotechnology Letters
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• v.51 no.2
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• pp.214-216
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• 2023

Meropenem-resistant Pseudomonas peli CJ30 was isolated from the Han River, South Korea. The genome of strain CJ30 comprising 4,919,106 bp with a G + C content of 60.0% was assembled to nine contigs. The draft genome sequence contained 5,411 protein-coding genes, 18 rRNA genes, and 70 tRNA genes. Strain CJ30 contained bla_SFC-3 and ampC β-lactamase gene.

• Journal of Food Hygiene and Safety
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• v.37 no.5
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• pp.306-309
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• 2022

Probiotics are live microorganisms that confer health benefits onto the host when administered at adequate doses. Most widely used probiotics, such as lactobacilli and bifidobacteria, are known to be elements of healthy gut microflora and hence are not considered a threat to the host. However, probiotics may pose a risk in certain populations with compromised immune systems or defects in gut barrier functions. Herein, we evaluated the safety of Bifidobacterium breve BB077, according to the safety evaluation guidelines for probiotics produced by the National Institute of Food and Drug Safety Evaluation (NIFDS). The results show that B. breve BB077 is both non-hemolytic and non-cytolytic. In contrast, B. breve BB077 exhibited higher streptomycin and tetracycline resistance than the suggested NIFDS standard cut-off values. Hence, a genetic analysis of the streptomycin and tetracycline resistance genes was performed to determine the origin of antimicrobial resistance. Streptomycin and tetracycline resistance was shown have arisen from chromosomal mutations and considered intrinsic to the taxonomic group. In conclusion, the B. breve BB077 strain might be safe for human consumption.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.217-224
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• 2016

Acinetobacter baumannii (A. baumannii) is prevalent in hospital environments and is an important opportunistic pathogen of nosocomial infection. It is known that this pathogen cause herd infection in hospitals, and the mortality rate is remarkably higher for patients infected with this pathogen and already have other underlying diseases. Herein, we investigated the antibiotic resistance rate and the type of resistance genes in 85 isolates of multi-drug resistant A. baumannii from the samples commissioned to laboratory medicine in two university hospitals-in hospital A and hospital B-located in Cheonan and Chungcheong provinces, respectively, in Korea. As a result, $bla_{OXA-23-like}$ and $bla_{OXA-51-like}$ were detected in 82 stains (96.5%). These 82 strains of $bla_{OXA-23-like}$ producing A. baumannii were confirmed with the ISAba1 gene found at the top of the $bla_{OXA-23-like}$ genes by PCR, inducing the resistance against carbapenemase. The armA, AME gene that induces the resistance against aminoglycoside was detected in 34 strains out of 38 strains from Hospital A (89.5%), and in 40 strains out of 47 strains from Hospital B (85.1%), while AMEs were found in 33 strains out of 38 strains from Hospital A (70.2%) and in 44 strains out of 47 strains in Hospital B (93.6%). Therefore, it was found that most multi-drug resistant A. baumannii from the Cheonan area expressed both acethyltransferase and adenyltransferase. This study investigated the multi-drug resistant A. baumannii isolated from Cheonan and Chungcheong provinces in Korea, and it is thought that the results of the study can be utilized as the basic information to cure multi-drug resistant A. baumannii infections and to prevent the spread of drug resistance.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.129-134
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• 2003

The purpose of the present study was to screen the effective of lactic acid bacteria (LAB) as probiotics, which are able to protect aquacultural fish pathogenic bacteria, and investigate their characterization. Twenty strains of lactic acid bacteria were isolated from fish intestine, fermented fish foods and kimchis. These bacteria were screened for antagonistic activity against fish pathogenic bacteria. Seven tested LAB strains were able to inhibit the fish pathogenic bacteria, including Vibrio anguillarum, Edwardsiella tarda, and Streptococcus sp.. Of the probiotic candidates, BK19 strain isolated from fermented pollack viscera indicated the largest inhibition activity. Moreover, this strain showed a resistance over low pH and antibiotic agents. Therefore this probiotic candidate BK19 was finally selected and identified as a probiotic strain. This particular probiotic bacteria was identified as Lactobacillus sakei BK19 by biochemical characteristics and 165 rRNA PCR amplification.

• Journal of fish pathology
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• v.34 no.1
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• pp.39-46
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• 2021

Tetracycline (TC) is one of the antibiotics used for treatment of bacterial infection in Korea. Inadequate usage and abuse cause the resistance to antibiotics, like Tetracycline, Erythromycin, and Fluoroquinolone. It can also affect severe economic loss in aquaculture field in Korea. We isolated 101 bacterial samples from diseased fish at aquaculture sites in Gyeonggi-do during 2015~2018. Minimum inhibitory concentration (MIC) method has been used to determine distribution and to identify bacterial isolates resistant to antibiotics including Oxytetracycline (OTC), Ampicillin (AMP), Clindamycin (CLI), Enrofloxacin (ENRO), Gentamycin (GEN). TC resistant isolates were confirmed antibiotic resistant genes by conventional PCR. Bacterial isolates were identified as Aeromonas spp. (43.5%), Pseudomonas spp. (4.0%) and Vibrio spp. (5.0%). It was confirmed that multi-resistant isolates (77.2%) were predominant over single-resistant one (22.8%). TC resistant genes like tet(A), tet(D), tet(E), tet(G), tet(M), and tet(S) were detected and tet(A) was the most prevalent. Aeromonas spp. is a dominant strain in bacterial infections in fishes of aquaculture sites, and further investigation on various antibiotic resistance genes will be needed for clear understanding of aquaculture sites in Gyeonggi-do.

• Journal of Marine Life Science
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• v.8 no.1
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• pp.50-55
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• 2023

Probiotics have been isolated from various environments and Bacillus species are advantageous among the probiotic bacteria due to their ability to form endospores that can compensate for the limitation of typical probiotics such as lactic acid bacteria. The aim of this study is to investigate the probiotic potential of Bacillus species from Ulleungdo soil, known as an unpolluted environment in Korea. Soil samples were collected from various areas of Ulleungdo, and Bacillus spp. were isolated, and assessed for antibiotic resistance and enzymatic activity. Six Bacillus spp. were not resistant to all tested antibiotics and subsequently tested for enzyme activity. We found the six Bacillus spp. were all inactive β-glucuronidase enzyme, which can have detrimental effects on human health, and one of Bacillus spp. showed an activity of Leucine arylamidase suggesting its probiotic potential.