• Pediatric Infection and Vaccine
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• v.13 no.1
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• pp.71-77
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• 2006

Purpose : Shigellosis is still an important cause of acute food-borne diarrheal diseases throughout the world. We investigated the transmission routes and clinical course through the outbreak of shigellosis in Mapo-Gu, Seoul. Methods : From October 7th to November 19th in 2005, Mapo-Gu public health center had referred 32 patients with confirmed or suspected shigellosis to the National Medical Center. We had investigated source of infection, epidemiology, laboratory findings, and clinical course of the cases occurred during this outbreak. Results : Among 32 patients, 24 patients had been confirmed with shigellosis, 8 patients had been diagnosed with suspected shigellosis. They ranged in age from 5 months to 12 years old and their mean age was 6.5 years. The clinical manifestations were as follows; diarrhea, fever, abdominal pain and asymptomatic condition. Symptoms had sustained for 3.7 days on the average. S. sonnei were cultured by rectal swab and founded to be resistant to ampicillin and TMP/SMX except to 3rd generation cephalosporin. After treatment with antibiotics such as cefixime and ceftriaxone or imipenem and conservative treatment with electrolyte and fluid replacement for 5~7 days, Stool cultures of the rectal swab grew no Shigella in these cases except 3 cases. Conclusion : An outbreak of shigellosis had occurred in a preschool and elementary school children. From the same results of antimicrobial susceptibility and pulsed-field gel electrophoresis patterns in this study, we suggest that the outbreak of shigellosis in this report had been originated from a single strain. According to all negative results about suspected food and water cultures, we couldn't find out source of infection. Through materials offerred by Mapo-Gu Public Health Center, we presumed the trasmission routes probably were person-to-person.

• Clinical and Experimental Pediatrics
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• v.48 no.10
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• pp.1107-1115
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• 2005

Purpose : An outbreak of ESBL-producing Shigella sonnei enteritis was unprecedented not only in Korea but throughout the world in the past. We intended to devise a management guideline for ESBL-producing shigellosis based on analysis of clinical manifestations and response to therapy. Methods : We analyzed 103 patients who were admitted to the hospital with acute GI symptoms and were shown positive result for S. sonnei on stool culture. We performed sensitivity test to the antibiotics and DNA sequencing of ESBL gene in the isolated S. sonnei colonies. In addition, we retrospectively analyzed their clinical characteristics, laboratory results, and clinical and microbiological responses to the antibiotics. Results : Among the clinical manifestations, fever was the most frequent(96.1%), followed by diarrhea(93.2%), abdominal pain(76.7%), headache(71.8%), vomiting(65.0%), and nausea(41.7%). The fever was sustained for average of 2.0 days and diarrhea for 3.9 days. Watery diarrhea was the most common(69%) followed by mucoid(26%), and bloody stool(5%). On peripheral blood smear, leukocytosis was noted in 53.4% of patients, and 78.6% of patients tested positive for serum CRP response. On stool direct smear, 11.7% of patients showed more than 50 WBCs/HPF, and 9.7% of patients between 5 to 20 WBCs/HPF. Stool occult blood was positive in 71% of patients. Production of CTX-M-14 type ESBL was reported for all S. sonnei strains isolated from this outbreak. Microbiological eradication rates to various antibiotics were as follows : 100%(9/9) to ciprofloxacin, 100% 5/5) to azithromycin, 6.9%(5/72) to cefdinir, 0%(0/8) to ceftriaxone, 12.5%(1/8) to ceftizoxime, 0%(0/ 8) to TMP/SMX, 42.9%(3/7) to ampicillin/sulbactam, 20%(1/5) to amoxicillin/clavulanic acid, and 68.8 %(11/16) to imipenem/cilastatin. Conclusion : It is presumed that azithromycin can be an attractive option for the treatment of ESBL-producing S. sonnei enteritis in pediatric population, given its cost-effectiveness and safety. Although ciprofloxacin is another cost-effective agent, its use in pediatric population may be a bit too premature.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.16-22
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• 2010

Purpose : We aimed to investigate the clinical and phylogenetic characteristics of Escherichia coli Urinary Tract Infections (E. coli UTI). Methods : We enrolled patients with culture-proven E. coli UTI, who were admitted at the study hospital from September 2008 to August 2009. We investigated clinical data of patients with E. coli UTI and characteristics of isolated E. coli strains. The phylogenetic groups were classified using triplex polymerase chain reaction (PCR), and the distribution of nine virulent genes was determined by multiplex PCR. Results : A total of 47 patients have participated in this study. Thirty (63.8%) were under 6 months; eight (17.0%) were between 6-12 months; and nine (19.1%) were over 12 months. We compared two age groups between under 6-month and over 6-month. In the age group under 6-month, higher proportion of male (P =0.002) and group B2 strains (P =0.020) were observed. In contrast, higher proportion of female and group non-B2 strains were observed in age group over 6-month. Frequencies of papC, papGII, papGIII, sfa/foc, hlyC, cnf1, fyuA, iroN and iucC were estimated as 68.1%, 57.4%, 42.6%, 46.8%, 46.8%, 31.9%, 87.2%, 48.9% and 63.8%, respectively. In the comparison of phylogenetic groups, group B2 showed higher distribution of virulent genes, while group D included more strains resistant to trimethoprim/sulfamethoxazole (TMP/SMZ) than other groups. Conclusion : We showed the age group-specific difference in the distribution of sex ratios and phylogenetic groups; more male and group B2 strains in age group under 6-month, while more female and group non-B2 in age group over 6-month. However, further evaluation including larger number of patients will be necessary to confirm above thesis in future molecular epidemiological studies.

• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.777-783
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• 2006

Purpose : Urinary tract infection(UTI) is one of the most frequent infections in children. E. coli is the most frequent etiological micropathogen in pediatric community UTI, and E. coli has developed resistance to many antibiotics, highlighting the need for regular surveys of this organism resistant patterns in the community. The aim of this study was to determine the oral antibiotic susceptibility patterns of E. coli, isolated from pediatric patients with uncomplicated community acquired UTI. Methods : E. coli isolates, obtained from pediatric patients with uncomplicated community acquired UTI between October in 2004 to September in 2005. And minimal inhibitory concentrations(MICs) of oral aminopenicillins and beta-lactamase inhibnitors(ampicillin, amoxacillin, ampicillin-sulbactam), oral cephalosporins(cefaclor, cefixime) and sulfa drug(trimethoprime-sulfamethoxazole) were performed according to the National Committee for Clinical Laboratory Standards(NCCLS) guide line. Results : Total 211 organisms were isolated from pediatric out-patients with community UTI. E. coli was the most common organism(89 percent), followed by E. fecalis, Proteus species, S. aureus, M. morganii, and P. aeruginosa. The resistant rates of aminopenicillins and beta-lactamase inhibitors, cefaclor and sulfa drug to E. coli were very high. But, the resistant rate of cefixime was markedly low, and ESBL strains were isolated with small rates. Conclusion : Our study results suggest that aminopenicillins, cefaclor and sulfa drug may not be useful as first line empirical antibiotics to treat pediatric patients with community UTI in Korea. But, 3rd generation cephalosporin such as cefixime can be used as effective second line antibiotics after primary treatment failure, also may be useful as an empirical first line antibiotic. Finally, we conclude that a continuous surveillance study to monitor susceptibility patterns of E. coli in community UTI will be needed for the standard guide lines of empirical oral antibiotic treatment.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.46-55
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• 2005

Purpose : Recurrent urinary tract Infection(UTI) in primary vesicoureteral reflux(VUR) may lead to serious renal scarring, a major cause of childhood hypertension and end-stage renal disease. To prevent recurrent UTI, low-dose long--term antibiotic prophylaxis has been recommended. However, recurrent UTI still develops during antibiotic prophylaxis, the efficacy of which is now being disputed. The emergence of resistant bacteria has also raised concerns. To evaluate the effect of antibiotic prophylaxis, we investigated recurrent UTI during prophylactic antibiotic use in children with primary VUR Materials : The incidence and risk factors of recurrent UTI were retrospectively evaluated in ninety-one children with primary VUR on trimethoprim- sulfamethoxazole(TMP/SMX) prophylafis during the year following their index febri]e UTI. Results : Recurrent UTI occurred in 31.9%(29/91) children and comprised 0.32 episodes/patient year. Febrile UTI was 0.26 episode/patient year and afebrile UTI was 0.07 episodes/patient year. The recurrent rate of UTI in male patients with phimosis was 37.2%(19/51), which was significantly higher than in males without phimosis 0%(0/5)(P=0.025). In the logistic regression analysis for recurrent UTI, renal scar was the significant risk factor for recurrent UTI [RR 3.8(95% CI 1.0-14.1) P=0.04]. For other well-known risk factors such as sex, age, degree of VUR, APN, and voiding dysfunction, the differences were not significant. Conclusion : TMP/SMX prophylaxis did not prevent recurrent UTI in children with primary VUR. Phimosis and renal scars were the risk factors for recurrent UTI but the grade of primary VUR was not. In VUR without phlmosis and renal scar, a randomized controlled study without antibiotic prophylaxis is required. (J Korean Soc Pediatr Nephrol 2005;9:46-55)

• Membrane Journal
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• v.22 no.2
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• pp.135-141
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• 2012

This study was carried out to find the optimum coagulation conditions for ceramic microfiltration process of Y water treatment plant. When pH of raw water from Y Dam was adjusted to 7, the efficiency of coagulation was the best and the optimun dosage of coagulant was 3 mg/L(as $Al_2O_3$) for turbidity of raw water less then 10 NTU in Jar test. In mini module test, the decay rate of specific flux was the lowest when PAC (poly Aluminum Chloride) was used among coagulants and pH was adjusted to 7. The decay rate of specific flux for raw water turbidity of 10~30 NTU was greatly decreased with increase of dosage of coagulant (PAC) while the rate was not significantly decreased for turbidity more than 50 NTU. In conclusion, the optimum dosage of PAC (11% as $Al_2O_3$) was 30 and 50 mg/L for raw water turbidity of less than 10 NTU and more than 50 NTU, respectively. The dosage of PAC should be increased linearly 30 to 50 mg/L depending on raw water turbidity of 10 to 50 NTU.

• Korean journal of applied entomology
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• v.33 no.2
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• pp.56-59
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• 1994

Life histoy of Nysius plebejrrs, the most injurious pest in chysanthemun cultivation in Korea, was studies both in field and inseday in Chinju during 1991 and 1992 seasons, and resulis are summarized as below 7hls insect has 3 generation per year, adult peaks on the mid April, mid June and late August, and the highest number of adults were attracted to the light tmp from the late August through mid September. Overwntered generation and needed 6-7weeks from egg rnatulity m spring, and 5-6 weeks, for both the first and second generation m summer, Incubation egg periods were 142, 9.3 and 7.2 days, nymphal penods were 45.2, 32.1 and 31.2 days, and total growth periods, were 59.4. 41 4 and 38.4 days, respect~vely for the overwintered, flst and second generation. Ovipositional penods were 25.6, 23.4 and 21.2 days. and number of eggs Iald by each female were 41.5. 37.2 and 35.4 days, respedively of each generation Longevities of female were 326, 27.5 and 25.1 days. and of male were 15 2, 12.3 and 12.1 days. respectively of each generation. Sex ratlo was about 1:1 in all generation, and eggs were laid in mass on the surface of leaves or stems of the host plants. This insed over-wmters as adult (90%) or 5th instar nymph (10%), however, over-wintering adults seem to be sexually premature, and mating take place actively in the following spring.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.103-114
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• 2017

A membrane bioreactor by sequentially alternating the inflow and by applying a two-stage coagulation control based on pre-coagulation was evaluated in terms of phosphorus removal efficiency and cost-savings. The MBR consisted of two identical alternative reaction tanks, followed by aerobic, anoxic and membrane tanks, where the wastewater and the internal return sludge alternatively flowed into each alternative reaction tank at every 2 hours. In the batch-operated alternative reaction tank, the initial concentration of nitrate rapidly decreased from 2.3 to 0.4 mg/L for only 20 minutes after stopping the inflow, followed by substantial release of phosphorus up to 4 mg/L under anaerobic condition. Jar test showed that the minimum alum doses to reduce the initial $PO_4$-P below 0.2 mg/L were 2 and 9 mol-Al/mol-P in the wastewater and the activated sludge from the membrane tank, respectively. It implies that a pre-coagulation in influent is more cost-efficient for phosphorus removal than the coagulation in the bioreactor. On the result of NUR test, there were little difference in terms of denitrification rate and contents of readily biodegradable COD between raw wastewater and pre-coagulated wastewater. When adding alum into the aerobic tank, alum doses above 26 mg/L as $Al_2O_3$ caused inhibitory effects on ammonia oxidation. Using the two-stage coagulation control based on pre-coagulation, the P concentration in the MBR effluent was kept below 0.2 mg/L with the alum of 2.7 mg/L as $Al_2O_3$, which was much lower than 5.1~7.4 mg/L as $Al_2O_3$ required for typical wastewater treatment plants. During the long-term operation of MBR, there was no change of the TMP increase rate before and after alum addition.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.100-110
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• 2016

Alkaline Peroxide Mechanical Pulping (APMP) of Pinus densiflora harvested from domestic mountains was explored. APMP contributes to various advantages including pulp quality, elimination of the need for a bleaching process, and energy savings. Sequential treatment of impregnation of bleaching chemicals and refining not only overcome the concern of alkaline darkening of wood chips during chemical impregnation, but it also brightens the chips to the desired brightness levels suitable for writing and printing papers. APMP pulping from Pinus densiflora was greatly influenced by the dosage levels of hydrogen peroxide and sodium hydroxide. Alkaline peroxide treatment was carried out by applying one of three levels of hydrogen peroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips) and one of three levels of sodium hydroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips). Other chemicals including a peroxide stabilizers and metal chelation were constantly added for all treatments. Chemical treatment with a liquor-to-wood ration of 9:1 was carried out in a laboratory digestor. Compared to BTMP, APMP pulping displayed outstanding characteristics including the less requirement of refining energy, the better improvement of tensile strength, the more reduction of shives, and the greater increase of pulp brightness. In particular, when 4.5% of hydrogen peroxide with impregnation during 90 minutes was used, the brightness of APMP reached 64.9% ISO. Even though bulk of APMP was decreased with the increase of sodium hydroxide, a better and improved balance could be achieved between optical and strength properties. The spent liquor obtained from the discharge of the impregnation process at the dosage level of 4.5% hydrogen peroxide exhibited an equal level of residual peroxide with BTMP. In conclusion, APMP pulping showed successful results with Pinus densiflora due to its better response to the development of optical and physical properties compared to TMP pulping.

• Membrane Journal
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• v.24 no.2
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• pp.142-150
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• 2014

This paper is to develop the process suitable for the advanced treatment of liquid fertilizer from the livestock night soil treatment facility (biogas plant). Nanofiltration (NF) and reverse osmosis (RO) process was used, respectively, for the advanced treatment of liquid fertilizer. And membrane bioreactor (MBR) with and without biomedia were tested, respectively, for the pretreatment. It was found that almost T-N of the liquid fertilizer was composed of ammoniacal nitrogen. Transmembrane pressure of MBR with biomedia increased slowly during the operation time, while that of MBR without biomedia increased rapidly at the initial time. But there was no difference observed in the removal efficiencies of COD, T-N, and T-P irrespective of the dosage of biomedia. When the liquid fertilizer was pretreated by MBR with biomedia, the removal efficiencies of COD, T-N, and T-P were 99.8, 86.5%, and 99.8% by NF, and 99.9, 86.8%, and 99.8% by RO, respectively. Compared with the effluent quality standards of the livestock night soil treatment facility, the water quality treated by MBR and NF/RO process met the standard for COD and T-P, but exceeded the permitted standard for T-N. In order to meet the effluent quality standard for T-N, it is necessary to change the MBR operation cycle or to add the secondary treatment by NF/RO.