• Journal of Microbiology and Biotechnology
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• v.32 no.1
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• pp.46-55
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• 2022

Clostridioides difficile infection (CDI) is a significant cause of hospital-acquired and antibiotic-mediated intestinal diseases and is a growing global public health concern. Overuse of antibiotics and their effect on normal intestinal flora has increased the incidence and severity of infections. Thus, the development of new, effective, and safe treatment options is a high priority. Here, we report a new probiotic strain, Bacillus amyloliquefaciens (BA PMC-80), and its in vitro/in vivo anti-C. difficile effect as a prospective novel candidate for replacing conventional antibiotics. BA PMC-80 showed a significant anti-C. difficile effect in coculture assay, and its cell-free supernatant (CFS) also exhibited a considerable anti-C. difficile effect with an 89.06 ㎍/ml 50% minimal inhibitory concentration (MIC) in broth microdilution assay. The CFS was stable and equally functional under different pHs, heat, and proteinase treatments. It also exhibited a high sensitivity against current antibiotics and no toxicity in subchronic toxicity testing in hamsters. Finally, BA PMC-80 showed a moderate effect in a hamster CDI model with reduced infection severity and delayed death. However, further studies are required to optimize the treatment condition of the hamster CDI model for better efficacy and identify the antimicrobial compound produced by BA PMC-80.

• Biomedical Science Letters
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• v.3 no.1
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• pp.55-67
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• 1997

Considering many problems caused by the abuse of antibiotics recently, the appearance of antibiotic resistance bacteria is believed to help the cure of patients greatly. From Jan. 1st, 1996 to Dec. 31, 1996, 6135 strains were examined after being asked of and seperated from the clinical pathology departments of general hospitals, and the isolation frequency of identified bacteria and the susceptibility of antibiotics showed the following result. 1. The isolation frequency of strains was Escherichia coli, 1134 strains (18.4%), Pseudomonas aeruginosa, 856 strains (13.9%), coagulase negative Staphylococcus, 793 strains (12.89%), Staphylococcus aureus, 555 strains (9.02%), B. cepacia, 421 strains (6.84%), Enterobacter cloacae, 366 strains (5.95%), Enterobacter faecalis (4.86%), and Klebsiella pneumonia, 220 strains (3.85%). 2. The isolation rate of specimen was urine, 1, 969 strains, wound 1, 104 strains, sputum 701 strains, blood 643 strains, vaginal swab, 342 strains, and eye discharge, 192 strains, 40% of urine strains were E. coli 18％ of wound strains were B. cepacia, 43.7％ of sputum were P. aeruginosa, and in blood strains there were Enterobacter cloacae (25.8%), coagulase negative Staphylococcus (19.6%), and P. aeruginosa (8.7%). 3. The result of antibiotics susceptibility showed that, among gram negative bacilli, P. aeruginoas had resistance in almost all antibiotics except ceftazidme imipenem. But B. cepacia, the same glucose non-fermentation gram negative bacilli had more than 90％ of sensitivity in aztreonam, ceftazidime, ciproflxacin, piperacillin, trimethoprim/sulfa and had resistance in the others. Enterococcus faecalis showed more than 85% of sensitivity in penicillin-G, ampicillin, ciprofloxacin. 4. In the case of specimen antibiotics susceptibility, Enterobacter cloacae was lower in specimen isolated from blood than in those isolated from others and p. aeruginosa was low in specimen isolated from urine, which showed that there was difference in specimen antibiotics susceptibility. The result of this study shows that there happen many resisitances in antibiotics used frequently and some countermeasure is necessary because many bacteria began to show new resistance. Also it is desirable that the choice of antibiotics for infection diagnosis and its cure should be made after the inspection of antibiotics.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.214-222
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• 2004

Purpose: Appropriate antibiotic therapy is important in childhood urinary tract infection and the selection of anibiotics is based on antimicrobial sensitivity of Escherichia coli. Extended-Spectrum ${\beta}-Lactamase(ESBL)$ is an enzyme produced by gram-negative bacilli that has the ability to hydrolyse penicillins, broad-spectrum cephalosporin and monobactam. There have been many reports of outbreaks of hospital infection by ESBL-producing organism. However, community-acquired infection with ESBL-producing organism are rare. This study was performed to retrospectively identify the incidence, characteristics and risk factors of ESBL (+) E. coli in community-acquired childhood UTI. Methods: In 288 children admitted in Ewha Womans University Hospital with E. coli UTI from Mar 2001 to February 2003, ESBL was isolated. ESBL was confirmed by the utilization of an automatized machine(Vitek GNS 433 card) using liquid medium dilution method according to National Committee for Clinical Laboratory Standard. The clinical characteristics, risk factors, antimicrobial resistance and treatment effectiveness were compared with ESBL(-) E. coli UTI. Results: Of 288 E. coli isolates, 31(10.8%) produced ESBL and 93.5%(29/31) occurred in infants younger than 6 month of age(P<0.01). No significant differences were noted in prior antibiotic use, prior admission history and underlying urogenital anomaly. Antimicrobial resistance was significantly higher in ESBL(+) E. coli compared with control patients (P<0.05). Although ceftriaxone showed 100% resistance in ESBL(+) E. coli, bacteriologic sterilization rate after ceftriaxone therapy was higher(96.8%). However, the recurrence rate of febrile UTI within 6 months was higher(25.8%) than control patients(6.6%). Conclusion: Epidemiologic study is required to find out any new risk factors of community-acquired ESBL(+) E. coli UTI and changes in selection of empirical antibiotics should be considered.

• Tuberculosis and Respiratory Diseases
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• v.65 no.2
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• pp.91-98
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• 2008

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is the most common organism associated with nosocomial infections. MRSA infections are becoming increasing important because they have emerged no only as healthcare-associated (HA) infections but also as community-associated (CA) ones. This study examined the moleculo-epidemiology of MRSA, which was isolated from nasal swabs in the intensive care unit (ICU) at Konyang University Hospital. MRSA are classified into HA-MRSA and CA-MRSA. Methods: From June to September 2006, 353 patients who were admitted to the ICU in Konyang University Hospital were enrolled in this study. Single nasal swabs were obtained for culture in the ICU on the 1st day. Pulsed-field gel electrophoresis and the antimicrobial resistant patterns were analyzed between HA- and CA-MRSA. An antimicrobial sensitivity test was also performed. Results: Forty two strains of MRSA were isolated from 353 patients (11.9%). Among the 42 isolates, HA-MRSA and CA-MRSA were found in 33 (78.6%), and 9 (21.4%), respectively. Eleven different PFGE types (type A to K) were identified. Types A (n=9) and B (n=7) were the most common for HA-MRSA, and types A (n=2) and B (n=2) were identified in CA-MRSA. The proportion of types A and B in CA-MRSA (44.4%) was similar to that in HA-MRSA (48.5%). The rates of resistance rates to erythromycin and ciprofloxacin were higher in HA-MRSA than in CA-MRSA. Conclusion: The rate of isolation of MRSA in an ICU setting was 11.9%. HA-MRSA was isolated more frequently than CA-MRSA. The rate of resistance of HA-MRSA to erythromycin and ciprofloxacin was higher than that of CA-MRSA. Despite the small number of subjects, the main isolates (type A and B) of CA-MRSA were similar to those of HA-MRSA.

• Microbiology and Biotechnology Letters
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• v.1 no.1
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• pp.51-57
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• 1973

2,2'-Methylene bis (3,4,6-trichloroacetoxy benzene) had been synthesized from Hexachlorophene. The eleven new derivatives -(2,2'Methylene bis [3,4,6-trichloro o-(${\beta}$-anilinopropionoxy) benzene]: m. p 173∼4$^{\circ}C$, C$\_$31/H$\_$24/N$_2$O$_4$Cl$\_$6/, 2,2' Methylene bis [3,4,6-trichloro (${\beta}$-Cyclohexylaminopropionoxy) benzene]: M. P, 187∼8$^{\circ}C$, C$\_$31/H$\_$36/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-phenyl hydrazinopropionoxy) benzene]; M. P. 151∼3$^{\circ}C$, C$\_$33/H$\_$28/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-o-toluidinopropionoxy) benzene]: M. P. 172∼3$^{\circ}C$, C$\_$33/H$\_$28/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-p-todudinopropionoxy) benzene]: 153∼4$^{\circ}C$, C$\_$33/H$\_$28/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-o-chloro anilinopropionoxy) benzene]: 170∼2$^{\circ}C$, C$\_$31/H$\_$27/N$_2$O$_4$Cl$\_$8/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-p-sulfamilinopropionoxy) bengene]: M. P. 310-5$^{\circ}C$, C$\_$31/H$\_$24/N$_2$S$_2$O$\_$10/Cl$\_$8/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-piperidinopropionoxy) benzene]: M. P. 168∼2$^{\circ}C$, C$\_$29/H$\_$32/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis (3,4,6-trichloro (${\beta}$-morpholinopropionoxy) benzene]: M. P. 226∼8$^{\circ}C$, C$\_$27/H$\_$28/N$_2$O$\_$6/Cl$\_$6/, 2,2'-Methylene bis (3,4,6-trichloro (${\beta}$-2-amino pyridino propionoxy) benzene]; M. P. 145∼6$^{\circ}C$, C$\_$29/H$\_$22/N$_4$O$_4$Cl$\_$5/-were synthesized by Mannichs reaction as potential antimicrobial agents and their antimicrobial activity were tested against Bacillus subtilis, Pseudomonas ovalis, Escherichia coli, Staphylococcus aureus, aerogenes, Bacillus Acerobacter Polymyxa, Bacillus brevis, Streptomyces griseus, Candida troficalis, Rhodotorula glutinis, Candida utilis, Hansenula anamola, Saccharomyces cerevisiae in vitro. Among them, compounds of benzylamine and p-toludine showed an effective antimibrobial activity againt Bacillus subtilis and Pseudomonas ovalis.

• Restorative Dentistry and Endodontics
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• v.18 no.2
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• pp.515-525
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• 1993

The purpose of this study was to evaluate the susceptibility of anaerobic microorganisms to certain antibiotics and root canal cements. Prevotella intermedia(Bacteroides intermedius) ATCC 25611(serotype A), Fusobacterium nucleatum ATCC 25586, Actinomyces viscosus ATCC 15987 which are the predominant pathogenic anaerobes in dental root canals were cultured in BHI for 48 hours(Fig.1). After each $200{\mu}l$ of those broths with microorganisms was streaked on each surface of blood agar plate, 2 to 5 antibiotic discs which are impregnated with Tetrncycline, Erythromycin, Ampicillin, Clindamycin, or Vancomycin were applied on each surface of blood agar plate and cultured for 5 days anaerobically in the anaerobic chamber (Fig.2). 15 antibiotic discs for each kind of antibiotics and each species of microorganisms were tested. Also each kind of root canal cement tubes which include Zinc oxide eugenol cement, Zinc phosphate cement, Calcium hydroxide powder+DD.W., Calcium hydroxide paste(Pulpdent Tempcanal), or Vitapex(Table 1) were applied on the inoculated BAPs after $200{\mu}l$ of each experimental species of microorganisms was streaked on the surface of blood agar plates, and they were cultured for 5 days anaerobically in the anaerobic chamber(Fig.3). The sensitivity(antimicrobial effect) was determined by the diameter of the inhibition zone. The results are as follows: 1. The results of antibiotic susceptibility test(Table 2) 1) All of the tested antibiotics had antimicrobial activity with various degrees. 2) In Prevotella intermedia (old Bacteroides intermedius), the diameter of inhibition zone to Erythromycin($37.87mm{\pm}2.20$) was largest, those to Tetracycline($26.20mm{\pm}2.96$), Vancomycin($21.53mm{\pm}1.96$), Clindamycin($18.73mm{\pm}0.96$) was smaller than former orderly, and That to Ampicillin ($7.87mm{\pm}0.83$) was smallest. 3) In Actinomyces viscosus, the diameter of inhibition zone to Erythromycin($28.73mm{\pm}1.22$) was largest, those to Ampicillin($21.73mm{\pm}1.03$), Clindamycin($21.33mm{\pm}1.59$) was similarly next order, that to Vancomycin($19.00mm{\pm}1.96$) was smaller than Clindamycin, and that to Tetracycline($11.93mm{\pm}0.70$) was smallest. 4) In Fusobacterium nucleatum, the diameter of inhibition zone to Ampicillin($31.07mm{\pm}1.91$) was largest, that to Erythromycin($28.87mm{\pm}0.92$), Clindamycin($20.47mm{\pm}1.51$), Vancomycin ($16.73mm{\pm}0.96$), Tetracycline ($12.13mm{\pm}1.06$) are smaller than former orderly. 2. The results of root canal cements and pastes(Table 3) 1) The external diameter of tube is 4mm, so 4mm of the inhibition zone diameter means non-susceptable. Prevotella intermedia (old Bacteroides intermedius) was non-susceptable to Calcium hydroxide powder+D.D.W., Calcium hydroxide paste(pulpdent Tempcanal), and Actinomyces viscosus was non-susceptable to Zinc phosphate cement, Calcium hydroxide powder + D.D.W., Calcium hydroxide paste(pulpdent Tempcanal). 2) In Prevotella intermedia (old Bacteroides intermedius), the diameter of inhibition zone to Zinc oxide eugenol cement($13.67mm{\pm}3.30$) was largest, that to Vitapex($9.20mm{\pm}2.96$), Zinc phosphate cement($6.13mm{\pm}2.07$) was smaller than former. 3) In Actinomyces viscosus, the diameter of inhibition zone to Zinc oxide eugenol cement($17.40mm{\pm}5.20$) was largest and that to Vitapex($8.80mm{\pm}1.70$) was next order. 4) In Fusobacterium nucleatum, the diameter of inhibition zone to Vitapex($42.33mm{\pm}17.2$) was largest and those to Calcium hydroxide paste(Pulpdent Tempcanal)($14.47mm{\pm}3.72$) and Zinc oxide eugenol cement($8.93mm{\pm}2.71$), Zinc phosphate cement($8.20mm{\pm}2.27$), Calcium hydroxide powder+D.D.W.($5.53mm{\pm}2.10$)was next orderly. And then In Zinc oxide eugenol cement and Zinc phosphate cement group, two of fifteen samples showed no inhibition zone, in Calcium hydroxide powder + D.D.W. group, 8 of 15 samples showed no inhibition zone.

• Clinical and Experimental Pediatrics
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• v.48 no.7
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• pp.716-722
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• 2005

Purpose : A full view of the spectrum of all bacterial diseases in healthy children is essential to the establishment of public health priorities. Accurate information on the relative importance of the various pathogens in terms of the age of the affected patients, the site of infection and the case fatality rate are valuable to the clinician in choosing antimicrobial treatments. Methods : Fifty-nine episodes of bacteremia were analysed. Data were collected at Ilsan Paik Hospital from January 2000 to December 2003. Analysis of each collected episode included isolating pathogen from blood culture, diagnosis, hospital course, isolating pathogens from other tissue sites, and studying results of antimicrobial sensitivity tests. Results : Fifty-nine cases of community-acquired bacteremia were reviewed. The most common pathogen was Staphylococcus aureus(11 cases, 18.6 percent), followed by Salmonella(10 cases, 16.9 percent), E. coli(7 cases, 11.9 percent), Streptococcus pneumoniae(five cases, 8.5 percent), Streptococcus viridans(5 cases 8.5 percent). The most common diagnosis was bacteremia without an indentified focus(61 percent), followed by meningitis(12 percent), bacteremia with enteritis(10.2 percent) and bacteremia with urinary tract infection(8.5 percent). Salmonella was still an important causative agent of bacteremia. The relative importance of Haemophilus influenza and Streptococcus pneumoniae was lower than in other studies. The most common organism responsible for bacteremia without an identified focus was Staphylococcus aureus. The case-fatality was 3.4 percent for all cases of bacteremia. Conclusion : We reviewed the etiology of community-acquired bacteremia. These data may be useful in the establishment of public health priorities and serve as a reference for selection of antibiotics in the empirical therapy of suspected invasive bacterial infection.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.35-46
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• 2015

Recently, much attention has been paid to the development of a value-added food category containing probiotics so as to improve human health and prevent diseases. Among various foods, the health benefits of milk and dairy products are known to humanity, and could be attributed to the bioactive components present in milk. In fermented milk products, the health benefits could be due to suitable modulation activities produced by the action of probiotic bacteria. Besides the modification of various milk components, probiotics might also act directly as preventive and therapeutic agents against some severe diseases. Probiotics promote health via their positive effects on the immune response, stimulation of natural immunity, and modulation of the production of antimicrobial peptides, cytokines, and so on. Whey proteins, a byproduct of cheese production could also have anticarcinogenic, immunostimulatory, antimicrobial, and health-promoting activities such as improving insulin sensitivity and reducing fat deposition. Therefore, milk and dairy products containing probiotics could provide various opportunities in the field of functional foods. Additionally, these functional foods may be important in the human diet and may help improve human health and prevent diseases.

• Pediatric Infection and Vaccine
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• v.10 no.2
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• pp.159-166
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• 2003

Purpose : Streptococcus pneumoniae is part of the normal flora but is also responsible for causing many invasive diseases such as pneumonia, meningitis, and sepsis in addition to noninvasive diseases such as otitis in children. Multi-drug resistant strains has raised a lot of concern worldwide and thus the importance of prevention has been emphasized. We have analyzed the current serotypes and antibiotic sensitivity of each serotype as a baseline study to estimate the efficacy of the pneumococcal vaccine in Korean children. Methods : One hundred sixteen cases of pneumococcus cultured at Yonsei Medical Center from September 2001 to January 2003 were analyzed. The serotyping was done with the Quellung reaction and penicillin resistance was tested using the oxacillin disc diffusion method. Results : Pneumococcus were cultured from the sputum in 76 cases(65.5%), from the blood in 13 cases(11.2%), from the ear discharge in 12 cases(10.3%), from the throat in 7 cases(6.0%), from the nasal cavity in 2 cases(1.7%), and one case(0.9%) each from the cerebrospinal fluid, eye discharge, peritoneal fluid, post-operational wound, brain abscess, and catheter tip. Serotyping was possible with 98 cases and the following serotypes were found; 15 cases of type 19F(15.3%), 11 cases of 19A(11.2%), 8 cases of 11A(8.2%), 7 cases each of 6A, 14 and 3(7.1%), 6 cases each of 35, 6B and 23F(6.1%). Eighty two cases(70.7%) out of 116 cases were penicillin resistant and serotypes 19F, 19A, 11A, 23F, 6A, 9V constituted the majority, 48 cases(59.8%). These serotypes showed resistance to cotrimoxazole (74.4%), tetracycline(69.5%), and erythromycin(90.3%) as well. In the 22 cases cultured from children, 19A and 19F were found in 25.0%, 6A, 6B, and 23F in 10.0%, 11A, 14, 19, and 29 in 5.0%. Fifty percent(10/20) of the clinical isolates were represented in the current 7-valent pneumococcal protein conjugate vaccine, and 85%(17/20) when the cross-reacting serotypes were included. Penicillin resistance was found in 86.4%(19/22). Conclusion : The percentage of serotypes included in the 7 valent pneumococcal protein conjugate vaccine found in our study was 40.8% which was less than other prior studies. In anticipation of a change of pneumococcal serotypes, a nationwide multicenter study is needed before the initiation of pneumococcal vaccines in Korea.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.185-194
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• 2006

The aim of this study was to identify the bacteria isolated from endodontic lesions by cell culture and to determine the antimicrobial susceptibility of them against 8 antibiotics. The necrotic pulpal tissues were collected from 27 infected root canals, which were diagnosed as endodontic infection. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing $500{\mu}l\;of\;1{\times}PBS$. The sample solution was briefly mixed and plated onto a BHI-agar plate containing 5% sheep blood. The agar plates were incubated in a $37^{\circ}C$ anaerobic chamber for 2 to 5 days. The bacteria grown on the agar plates were identified by comparison of 16S rRNA gene (rDNA) sequencing method at the species level. To test the sensitivity of the bacteria isolated from the infected root canals against 8 antibiotics, minimum inhibitory concentrations (MIC) were determined using broth dilution assay. The data showed that 101 bacterial strains were isolated and were identified. Streptococcus spp. (29.7%) and Actinomyces spp. (21.8%) were predominantly isolated. The 9 strains were excluded in antimicrobial susceptibility test because they were lost during the experiment or were not grown in broth culture. The percentage of bacteria susceptible for each antibiotic in this study was clindamycin, 87.0% (80 of 92); tetracycline, 75.0% (69 of 92); cefuroxime axetil, 75.0% (69 of 92); amoxicillin + clavulanic acid (5:1), 71.7% (66 of 92); penicillin G, 66.3% (61 of 92); erythromycin, 66.3% (61 of 92); amoxicillin, 44.6% (41 of 92); and ciprofloxacin, 31.5% (29 of 92). The susceptibility pattern of 8 antibiotics was dependent on the host of the bacteria strains rather than the kinds of bacterial species. These results indicate that antibiotic susceptibility test should be performed when antibiotics are needed for the treatment of infected root canals.