• Environmental Analysis Health and Toxicology
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• v.21 no.3 s.54
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• pp.283-289
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• 2006

In recent years, there has been an increase in consumer demand for bottled waters. There is a perception that consumption of natural mineral water represents a healthy life style and that these products are relatively safe. In this study, the microbiological quality of 39 samples of bottled water, purchased from retail store in Korea, was investigated during the 2005. Applying pour plate method, the 1 mL of water samples were analyzed for the presence and enumeration of total general bacteria and Pseudomonas spp.. Nineteen samples representing 9 brands of bottled water contained general bacteria ($1.54{\times}10^2$ CFU/mL). In addition four samples contained Pseudomonas spp. and Camamonas acidovorans. The susceptibility of the strains tested against 25 antimicrobial agents, Pseudomonas fluorescens were resistant to Lincomycin, Amoxacilin/Clavulanic acid and Cefazolin (> $100{\mu}g/mL$). Also Comamonas acidovorans were intermediate to Cephalothin and resistant to Cefoperazone.

• Journal of Korean Dental Hygiene Science
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• v.5 no.2
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• pp.155-164
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• 2022

Background: By regulating the factors that contribute to oral diseases in a healthy way, oral health can be maintained and prevented. Methods: The general characteristics, PHP index, oral health behavior, and clinical periodontal index of each group were calculated by frequency analysis, and a cross-analysis (χ² test) was conducted to assess the homogeneity of the general characteristics, oral health behavior, and clinical periodontal index of the study subjects. An Oral bacteriological examination was performed by gargling with saliva. Results: The expert periodontal prevention group showed a decrease in the copy number of periodontal disease causative bacteria, and A. actinomycetemcomitans, P. gingivalis, T. forsythus, andT. denticolashowed a significant difference before and after treatment (p=0.021). In the periodontal treatment group, A. actinomycetemcomitans, P. gingivalis, T. forsythus, andT. denticolaall showed a decrease in copy number, but there was no significant difference. Conclusions: This study showed professional periodontal prevention management had some effect on periodontal bacterial reduction.

• Journal of Microbiology and Biotechnology
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• v.34 no.4
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• pp.854-862
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• 2024

Lactobacillus is a commonly used probiotic, and many researchers have focused on its stress response to improve its functionality and survival. However, studies on persister cells, dormant cells that aid bacteria in surviving general stress, have focused on pathogenic bacteria that cause infection, not Lactobacillus. Thus, understanding Lactobacillus persister cells will provide essential clues for understanding how Lactobacillus survives and maintains its function under various environmental conditions. We treated Lactobacillus strains with various antibiotics to determine the conditions required for persister formation using kill curves and transmission electron microscopy. In addition, we observed the resuscitation patterns of persister cells using single-cell analysis. Our results show that Lactobacillus creates a small population of persister cells (0.0001-1% of the bacterial population) in response to beta-lactam antibiotics such as ampicillin and amoxicillin. Moreover, only around 0.5-1% of persister cells are heterogeneously resuscitated by adding fresh media; the characteristics are typical of persister cells. This study provides a method for forming and verifying the persistence of Lactobacillus and demonstrates that antibiotic-induced Lactobacillus persister cells show characteristics of dormancy, sensitivity of antibiotics, same as exponential cells, multi-drug tolerance, and resuscitation, which are characteristics of general persister cells. This study suggests that the mechanisms of formation and resuscitation may vary depending on the characteristics, such as the membrane structure of the bacterial species.

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1101-1106
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• 2012

Market fresh makgeolli was stored at different temperatures of $4^{\circ}C$ and $25^{\circ}C$ to assess the change of the microbial diversity according to the storage temperature and period. Yeast counts increased until day 3 of storage and decreased thereafter. General and lactic acid bacterial counts continuously increased during storage. The data indicated that the control of growth of microorganisms, particularly general bacteria and lactic acid bacteria (LAB), is essential. Total acid levels started to decrease in the makgeolli stored at $4^{\circ}C$, and increased from day 6 of storage in the makgeolli stored at $25^{\circ}C$. The increase of total acid in the non-refrigerated condition greatly affected the quality of makgeolli. In both the fresh makgeolli samples stored at $4^{\circ}C$ and $25^{\circ}C$, yeast (Saccharomyces cerevisiae) and molds (Aspergillus tubingensis, Candida glaebosa, and Aspergillus niger) were noted. Denaturing gradient gel electrophoresis (DGGE) band patterns were almost constant regardless of the storage period. As for bacteria, Lactobacillus crustorum, L. brevis, and Microlaena stipoides were found in the makgeolli stored at $4^{\circ}C$, and L. crustorum, Lactobacillus sp., L. plantarum, L. brevis, L. rhamnosus, and L. similis were found in the makgeolli stored at $25^{\circ}C$. In particular, in the makgeolli stored at $25^{\circ}C$, L. crustorum and L. plantarum presented dark bands and were identified as the primary microorganisms that affected spoilage of fresh makgeolli.

• Korean Journal of Microbiology
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• v.6 no.4
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• pp.131-140
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• 1968

The soil of the reclaimed tidal land, located in Chogi-ri, Is. Kanghwa, Korea was used in this experiment. The experimented soil samples were collected from 18 sites with its time elapsed after the shore-protection works, soil-depth and the vegetation of saline plants, and at each site samplings were conducted monthly from March through October, 1968, for the purposes of examining the changes of microbial populations for the microbes such as bacteria, actinomycetes and fungi, by using the dilution plate method. The numbers of the microbes in these soils generally showed lower levels comparing with those of other soils. The more time elapsed after the reclamation, the higher numbers of the microbes inhibited the soils. Higher populations were there in the surface soils than in the lower part of the area. The surface soils included comparatively better conditions in aeration and contents of organic matter than in the lower part, and this fact was. same as in general soils. However, not so was this in the case of March, April and October due to the higher soil temperatures in the lows. At the experimental sites where the halophytes such as Salicorniu were grown vigourously, the more densly the plants grew, the higher populations of actinomycetes and fungi were, but not in the case of bacterial population. This means, in this soil with dense Salicornia, it is difficult to obtain good-natured soils in short time without a higher population of bacteria. For the rapid utilization of the land soil, in this view of point, the methods increasing the number of bacteria in the soil are needed as well as the cultivation and harvesting Salicorniu which indicated in the privious paper(Hong, et al., 1969a). According to the results of this experiment, the changes of soil-microbial populations in the reclaimed tidal land soil containing high salinity depend deeply upon the interrelations of many environmental factors such as soil-salinity, soil-components and contents, concentration of organic matters, pH, aeration, and air and soil temperatures, as in the general soils.

• Korean Journal of Microbiology
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• v.7 no.1
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• pp.29-40
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• 1969

Two kinds of organic materials, powders of Salicornia and Oryza sativa L. wre added as a source of organic matter to the suspensions of saline soils(soil : water = 1:3) to be 4 per cent of dried saline soil grams. And then, the samples were incubated at $28^{\circ}C$ to improve the decomposition of organic materials by soil microflora. Resutls of this experiment are summarized as followings : 1) The pH of soil suspension showed its highest value on the second or third week after the treatments, which were similar to those of the soil microflora. Results of this experiment are summarized as follwings : 1) The pH of soil suspension showed its highest value on the second ot third week after the treatments, which were similar to those of the soil microflora populations. 2) Salinity increased up to the second week and the highest value of it appeared in the samples which were treated with the powder of Salicornia. In general, the salinity of all samples decreased on the third week after the treatment. The fact was assumed the possibilities of desalination from saline soil by the microbial actions. 3) Soil microflora such as bacteria, actinomycetes and fungi, were determined its populations soil microflora is to act as decomposer in soil. Both of the bacteria and actinomycytes population showed in the third weak after the tratment. In general, 30-years old of saline soil contained microbial population much more than those of 5-year old of saline soil. Salicornia powder favored the increase of both the bacteria and fungal population, and Oryza sativa L. seemed to have been a great role in increase of actinomycetes. Especially, fungal population of the untreated soil suspension contained higher microbial populations more than those of the soils treated with both of the organic materials. 4) Sugar contents of soil suspesions decreased remarkably on the first week after the treatments. 5) The amount of nitrate had similar tendency to those of population changes of soil microflora. Total acidity decreased continuously and the amount of potassium showed its highest value on the third week treatment. However, the amount of phosphorus was determined to be insignificant.

• Food Science of Animal Resources
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• v.44 no.4
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• pp.805-816
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• 2024

The aim of this study was to evaluate a new Bacillus amyloliquefaciens B-1895 probiotic as a feed additive for farmed trout. Final weight, absolute and average daily gain of fish, and average daily growth rate were higher in the group that received the probiotic than in the control group (p<0.05). Moreover, the probiotic-fed trout had more intense growth rates than the control group (higher by 15.7%; p<0.05). A decrease in feed ratio was also observed in the group that received probiotic (25% decrease; p<0.05), indicating more efficient digestion and assimilation of feed. In general, the introduction of probiotic in the feed did not adversely affect the functional status of the fish. In young trout of the control group, when assessing the general chemical composition of the organism in the muscle tissue revealed significantly (p≤0.001) higher level of moisture content by 5.1% and lower by 11.0% dry matter content. In muscle, the protein content was higher by 1.33% (p≤0.001) and fat content by 2.1% (p≤0.001) in experimental fish. Generally, Lactobacilli, Enterococcus, Vibrio, Bacillus, and coliform bacteria were found in the intestinal samples of rainbow trout. Significant reliable difference (p≤0.05) between the samples of experimental and control groups was noted in the content of Bacillus bacteria. In the control group, 5.0±0.4×10³ CFU/g was detected, while in the experimental group 8.4±0.8×10⁴ CFU/g. Overall, the data indicate that probiotic bacteria B. amyloliquefaciens B-1895 has no adverse effect on selected microorganisms in the study fish.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1476-1480
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• 2016

Anti-microbial effects of the medium extracts from three different lactic acid bacteria (LB1, Lactobacillus acidophilus; LB2, Lactobacillus casei; LB3, Lactobacillus sicerae) were investigated. Three different extracts of lactic acid bacteria media (ELAM) did not show significant changes in pork loin quality after 3 and 14 days of cold storage such as general contents, colors, pH, and TBARS. To determine anti-bacterial activity of three ELAM, three pathogenic bacteria (Bacillus cereus, Bacillus subtilis, and Staphylococcus aureus) were obtained and incubated with ELAM-absorbed paper discs. ELAM of LB2 and LB3 showed significantly larger bacterial growth inhibitory zones compared with that of LB1 (P<0.05). When the pathogenic bacteria inoculated in pork loin with three ELAM, total microbial contents of pork loin treated with ELAM of LB3 after 14 days of cold storage showed significantly lower microbial contents compared to those of control, LB1 and LB2 (P<0.05). In conclusion, ELAM of LB3 derived from L. sicerae had the most effective pathogenic bacteria inhibitory activity on agar and pork loin. This is the first result to report the antibacterial effect of L. sicerae. If the safety and toxicity characteristics of L. sicerae are further investigated, this new lactic acid bacterium would have potential as an effective and nature-friendly food preserving agent.

• The Journal of the Korean Society for Microbiology
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• v.20 no.1
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• pp.35-44
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• 1985

Isolation and identification of anaerobic bacteria from blood cultures are still technically demanding procedures. Recently, with the use of gas liquid chromatography, the accuracy of identification is much improved. However, there has never been a satisfactory data analysis on anaerobic bacteremia in Korea. The authors evaluated both the clinical and the bacteriological data of 129 anaerobic bacteremias found at the Yonsei Medical Center during the period of 1973 to 1984. The most frequently isolated anaerobic bacteria were Bacteroides (52.7%), among which the major species was B. fragilis (38.7%). Incidence of anaerobic bacteremia by sex was 57% in male and 43% in female. Mortality was higg in groups below 1-year old and above 50-year old. The cause of death seemed closely correlated with the patient's age, general condition and the severity of the underlying disease. Various neoplasms were the most common (20%) underlying diseases predisposing the anaerobic bacteremia. Biliary tract was considered the most frequent route of infection in anaerobic bacteremia. The frequent clinical signs in anaerobic bacteremia were fever (65%), followed by liver function abnormality (29%), jaundice (20%) and hypotention(18%). When analysis of positive rate of blood culture was made on the patients from whom 4 cultures were done within 24 hours, it was found that 33% of the samples were positive. Isolation rate of anaerobic bacteria in thioglycollate medium was 83.8%, while it was 44% in Tryptic soy broth. Among the anaerobic bacteremia, 25.4% were polymicrobial infections with aerobic bacteria (92.5%), such as E. coli(33.3%). From these studies, it is concluded that B. fragilis is the most important causative organism in anaerobic bacteremia, with high fatality, particularly in those who have underlying diseases. The ports of entry are mainly biliary, gastrointestinal and female genital tract. Fever is the most frequent clinical sign. Single blood culture is not sufficient to detect all anaerobic bacteremia, therefore more cultures with optimal time interval are needed. The incidence of polymicrobial infection in anaerobic bacteremia is higher than that in overall bacteremia.

• 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.