• Clinical and Experimental Pediatrics
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• v.48 no.6
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• pp.619-623
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• 2005

Purpose : Bacteremia in immunocompromised pediatric cancer patients can lead to high morbidity and mortality, if not treated early and properly. The incidence and antibiotic sensitivities to common pathogens of bacteremia in pediatric cancer patients are liable to change, according to region and time. We investigated the causative organisms and antibiotic sensitivities of bacteremia in pediatric cancer patients to assess the adequacy of empiric antimicrobial therapy. Methods : From September 1995 to August 2003, we retrospectively evaluated 58 episodes in 39 pediatric cancer patients with bacteremia treated at the Pediatric Department of Yeungnam University Hospital. We investigated and analyzed the causative organisms and the antibiotic sensitivity test results by reviewing the records of the microbiologically proven positive blood culture results. Results : The incidence of bacteremia in pediatric cancer patients in this study was 5.7 percent (58 episodes out of 1,022 occasions of blood cultures). Gram-positive organisms were isolated more often than gram-negative organisms (63.8 percent vs 36.2 percent) in the following order : Staphylococcus epidermidis (37.9 percent), Staphylococcus aureus (17.3 percent), Escherichia coli (12 percent), Streptococcus (8.6 percent), Enterobacter (6.9 percent), Klesiella (6.9 percent), Serratia (3.5 percent), Acinetobacter (3.5 percent), Proteus (1.7 percent) and Morganella morganii (1.7 percent). In antibiotic sensitivity tests, only six of 37 isolates (16 percent) of gram positive bacteria were sensitive to penicillin and 15 of 37 isolates (40 percent) were sensitive to oxacillin. All except one Staphylococcus aureus were sensitive to vancomycin and all except one Staphylococcus epidermidis were sensitive to teicoplanin among 37 isolates of gram positive bacteria. In the case of gram negative bacteria, two of 21 isolates (10 percent) and four of 21 isolates (19 percent) were sensitive to cefotaxime and ceftazidime, respectively. Only six of 21 isolates (29 percent) were sensitive to aminoglycoside, but all 21 isolates (100 percent) were sensitive to imipenem. All seven isolates tested after the year 2000 were sensitive to meropenem. Conclusion : In conclusion, we should choose the proper antimicrobials in treating pediatric cancer patients with suspected bacteremia, reflecting the increasing episodes of gram positive bacteremia and polymicrobial resistance of gram positive and negative organisms.

• Korean Journal of Veterinary Service
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• v.20 no.3
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• pp.261-279
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• 1997

The study for a effect of monitoring on bovine mastitis was conduced for improvement of raw milk from Jan. to Dec. in 1996. Sampling the milk of 367 cows(1, 406 quarters) from 5 herds in Inchon and were carried out California mastitis test(CMT), somatic cell count(SCC), isolation of pathogens and antibiotic sensitivity tests. The results were summarized as follows, 1. The number of bovine mastitis was 177 cows(48.2%) and 371 quarters(26.4%) : clinical mastitis : 25 cows(6.8%), 32 quarters(2.3%) and subclinicsl mastitis : 152 cows(41.4% ), 339 quarters(24.1%). Incidence rate of mastitis by season were Summer 52.0%, Fall and Winter 48% and Spring 41%. Incidence rate of mastitis by quarters were Summer 30%, Fall 28%, Winter 25% and Spring 21%, respectively. 2. In the distribution of CMT degree by quarter, CMT positive(CMT$\pm$) of 1, 406 quarters milk were 50.1% (704 quarters). The ratio of CMT positivity by quarter were left front quarter 55.8%, right front quarter 48.9%, right hind quarter 48.6% and left hind quarter 47% The ratio of CMT positivity by season were Summer 54.1%, Fall 49.7%, Spring 48.5% and Winter 48% 3. The highest mean SCC by season among 5 herds was "A" herd. Mean SCC (cell/ml) of A herd were Summer 2, 032, 000cells/ml, Fall 1, 109, 000cells/ml, Winter 782, 000cells/ml and Spring 577, 000cells/ml. The lowest mean SCC by season among 5 herds was "E" herds. Mean SCC of E herd were Summer 1, 064, 000cells/ml, Spring 795, 000cells/m1, Fall 429, 000cells/ml and Winter 400, 000cells/ml. Mean SCC of the other herds by season were little difference. 4. The milk samples of "A" herd were collected from 10 cows. In 3 seasons, mean SCC of No. 2 and 3 cows were than 1, 000, 000cells/ml. In 1 season, mean SCC of No. 6, 7 and 8 cows were than 1, 000, 000cells/ml. The more than mean SCC 1, 000, 000cells/ml of cows by season were distributed Summer 4 cows, Winter 3 cows, Spring and Fall 1 cow respectively. The milk samples of "B" herd were collected from 14 cows. In 3 seasons, mean SCC of No. 1 cow was more than 1, 000, 000cells/ml. In 2 seasons, mean SCC of No. 5, 9 and 14 cows were more than 1, 000, 000cells/ml. In 1 season, No. 3, 6 and 7 cows were more than 1, 000, 000cells/ml. The more than mean SCC 1, 000, 000cells/ml of cows by season were distributed Fall and Winter 4 cows respectively, Summer 3 cows and Spring 1 cow. The milk samples of "C" herd were collected from 18 cows. In 2 seasons, mean SCC of No. 16 cow was more than 1, 000, 000cells/ml. In 1 season, mean SCC of No. 1, 2, 6, 7, 13, 15 and 18 cows were more than 1, 000, 000cells/ml respectively. The more than mean SCC 1, 000, 000cells/ml of cows by season were distributed Summer 5 cows, Fall 3 cows, Spring 2 cows and Winter 1 COW. The milk sampes of "D" herd were collected 24 cows. In 3 season, mean SCC of No. 14 cow was more than 1, 000, 000cells/ml. In 2 seasons, mean SCC of No. 14 and 18 cows were more than 1, 000, 000cells/ml. In 1 season, mean SCC of No. 1, 2, 3, 8, 12, 17, 19, 20 and 21 cows were more than 1, 000, 000cells/ml. The more than mean SCC 1, 000, 000cells/ml of cows were distributed Fall 15 cows, Spring and Winter 4 cows respectively and Summer 3 cows. The milk samples of "E" herd were collected from 27 cows. In 2 seasons, mean SCC of No. 6, 7 and 21 cows were more than 1, 000, 000cells/ml. In 1 season, mean SCC of No. 2, 4, 7, 11, 14, 16 and 23 cows were more than 1, 000, 000cells/ml. The more than mean SCC 1, 000, 000cells/ml of cows were distributed Spring and Fall 5 cows respectively, Summer and Winter 2 cows, respectively. 5. The rate of isolated pathogenic microorganisms from bovine mastitis were summarized as follows : Staphylococcus sp 168 strains(45.8%), Streptococcus sp 82 strains(22.3%), Gram(-) sp 45 strains(12.3%), Gram(＋) sp 51 strains and the other sp 21 strains(5.7%). 6. The highest of antibiotic sensitivity test of each microorganism was summarized as follows : Staphyolcoccus sp - cephalosporin 76%, gentamicin 55%, Streptococcus sp - ampicillin 61%, cephalosporin 63%, Gram(-) sp - gentamicin 58%, Gram(＋) sp - cephalosporin 63%, The other sp - cephalosporin 90%. Microorganisms showed the highest sensitivity(68%) to cephalospsorin. Microorganisms showed the highest sensitivity(68%) to cephalospsorin.

• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.305-312
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• 1998

In order to investigate the species, serobiological characteristics and antibiotic sensitivity of Pseudomonas spp, we isolated Pseudomonas spp from 57 spring waters around Seoul area for spring, summer and autumn and identified Pseudomonas spp by biochemical characteristics and serological method. And also we tested the antibiotic sensitivity test by discdiffusion method. Of 57 spring waters tested, Pseudomonas spp were isolated from 33 spring waters(57.9%). Isolation rate of Pseudomonas spp in spring season was 28.1%, summer 21.1% and autumn 28.1%. Only 1 spring water was detected Pseudomonas spp in all seasons and 9 (15.8%) were detected for 2 seasons and 13 (22.8%) were for only 1 season. Isolation rate of Pseudomonas spp at Mt. Cheonggye was 50% and followed by Mt. Bookhan 35.7%, Mt. Daemo 33.3%, Mt. Dobong 29.6%, Mt. Surak 25.9%, Mt. Woomyun 22.2% and Mt. Bulam 7.4%. Of 44 Pseudomonas spp, 22 strains (50%) were identified by Ps. putida, Ps. aeruginosa, Ps. fluorescens and Ps. mendocina were identified 6 strains (13.6%), respectively. 4 strains (9.1%) were identified by Ps. aureofaciens. Of 6 Ps. aeruginosa, serotype A was 2 strains, B, E, G, and K was 1 strain, respectively. Of 44 Pseudomonas spp, resistance rate to amoxicillin was 90.9% and followed by chloramphenicol 84.1%, tetracycline 84.1%, carbenicillin 81.8%, nalidixic acid 68.2%, neomycin 38.6%, streptomycin 31.8%, gentamicin 4.6%, kanamycin 4.6% and colistin 2.3%. Ps. aeruginosa was more sensitive to carbenicillin than other Pseudomonas spp isolated from spring waters in Seoul area but more resistant to kanamycin, and Ps. aureofaciens was no resistant to streptomycin. Among multiple drug resistance, resistance to 5 drugs was 31.8%, 4 drugs 15.9%, 7 drugs 13.6%, 1 drug and 2 drugs 4.6%, and 8 drugs 2.3%, respectively. The multiple resistance patterns detected highestly were NA-CB-C-TE-AMC (18.2%), NA-CB-N-C-TE-AMC (13.6%), CBC-TE-AMC (11.4%) and NA-CB-N-C-TE-AMC-S (9.1%).

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.79-84
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• 2002

Purpose : About 41% of obtained group A streptococci in the 1998 was reported as erythromycin-resistant streptococci in Seoul, Korea. The most common T serotype was T12, followed by T4 and T28. We'd like to monitor the serological changes and antibiotic sensitivity test of Streptococcus pyogenes obtained from the patients with pharyngotonsillitis and invasive diseases from 1999 through 2001. Also, it could be proposed to choose the proper antibiotic selection in the area where the rate of erythromycin-resistant streptococci is high. Methods : From Jan. 1999 to Oct. 2001, 208 isolates of group A streptococci were collected from inpatients and outpatients with pharyngotonsillitis, scarlet fever, and invasive infections in Seoul and Southern part of peninsula. All isolates were serotyped by T-agglutination, minimum inhibitory concentrations(MICs) which were determined by agar dilution methods, according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). Results : The most common T serotype was T12(29.8%), followed by T1(23.1%), T4 (14.9%). T1 was prominent serotype compared with previous year. T serotyping, among 25 isolates obtained from the patients with scarlet fever in Southern part of peninsula mostly, was T12, T1, and T4 in order of frequency. All the isolates tested were susceptible to penicillin, cefprozil, vancomycin, ceftriaxone, and chloramphenicol. However, 23 isolates(14.2%) was resistant to erythromycin and 18 isolates(11.1%) was resistant to clarithromycin. Serotype T12 was found to be the most resistant serotype to erythromycin and/or clarithromycin. Conclusion : High rate of erythromycin-resistant streptococci which surveyed in 1998 were reduced to 14.2% in this study. We should have to further evaluate the reason of decreased resistant strains and consider the resistant strains of streptococci in choosing the antibiotics. There was no serological characteristics according to the types of disease entities. Between the serologic distributions in Seoul and the Southern part of peninsula area are same, we could presume that the serological typing of strains obtained over the country may be not different.

• Parasites, Hosts and Diseases
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• v.49 no.4
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• pp.357-364
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• 2011

Various Leishmania species were engineered with green fluorescent protein (GFP) using episomal vectors that encoded an antibiotic resistance gene, such as aminoglycoside geneticin sulphate (G418). Most reports of GFP-Leishmania have used the flagellated extracellular promastigote, the stage of parasite detected in the midgut of the sandfly vector; fewer studies have been performed with amastigotes, the stage of parasite detected in mammals. In this study, comparisons were made regarding the efficiency for in vitro G418 selection of GFP-Leishmania amazonensis promastigotes and amastigotes and the use of in vivo G418 selection. The GFP-promastigotes retained episomal plasmid for a prolonged period and G418 treatment was necessary and efficient for in vitro selection. In contrast, GFP-amastigotes showed low retention of the episomal plasmid in the absence of G418 selection and low sensitivity to antibiotics in vitro. The use of protocols for G418 selection using infected BALB/c mice also indicated low sensitivity to antibiotics against amastigotes in cutaneous lesions.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.93-101
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• 1999

This test process on screening method for the detection of residual antibiotics in milk is simple, economic, sensitive to residual antibiotics and was given approval international organs. Thus, this study was carried out the comparison of Disk assay method and TTC-II method for sensitivity and minimum detectable range of antibiotics in raw milk. The results of this study was summarized as follows ; 1. The number of samples requested for treatment of mastitis was 198 samples. Comparison or analytical results among the methods of TTC-II, disk assay and Delve sp was that TTC-II 37 samples(18.6% ), Disk assay 125samples(63.1%), Delve SP 130 samples(65.7% ) reacted positively. Conformity rate of Delve SP and Disk assay was 70%. 2. Detectable limits of disk assay method in some antibiotics were more sensitive than those of official method(0.05-0.0025ppm in the $\beta$-lactams, 1ppm in two aminoglycoside, 0.2 ppm in one tetracycline, similar in one macrolide) 3. For sensitivity of residual sulfonamides TTC-II was much more sensitive than disk assay. Detectable limits of sulfamethazine and sulfadimethoxine were 30 to 50ppm levels. 4. The best medium preservation period is 1-2 days. 5. Concentration of brome cresol purple related to resistance for B stearothermophilus culture was 24ppm/ml. These results show that disk assay method for screening detection of antibiotics residuces in milk is worthy of use.

• Korean Journal of Microbiology
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• v.48 no.1
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• pp.22-28
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• 2012

Vibrio parahaemolyticus is one of the major agents responsible for food poisoning during summer in Korea, which is transmitted via seawater or seafoods. Recently, distribution of the bacteria in the marine environment has been increased due to global warming. Great concern also has been raised regarding public hygiene as well as marine culture by the emergence of pathogens with antibiotic resistance. Therefore, distribution of V. parahaemolyticus and antibiotic resistance of the isolates were monitored in 7 coastal areas of Kyonggi Province and Incheon by sampling seawater, fishes and clams monthly. V. parahaemolyticus was detected from 47.7% of 966 samples (seawater 61.9%, seafoods 41.8%) analyzed using $CHROMagar^{TM}$ and TCBS agar plates as well as multiplex PCR. Among 13 antibiotics tested, resistance to vancomycin and ampicillin was observed in 97.3% and 87.3% of the isolates, respectively, and the ratios of them resistant to cephalothin (48.8%) and rifampin (46.1%) were also high. The isolates were most highly sensitive to chloramphenicol (91.7%) and trimethoprim-sulfamethoxazole (91.8%). The ratio of sensitivity for other antibiotics was also high in the descending order of gentamycin (82.3%), tobramycin (74.8%), nalidixic acid (71.6%), tetracyclin (69.4%), cefotaxime (63.0%). About 69% of the isolates showed multiple drug resistance toward 3 antibiotics including vancomycin and ampicillin. Two of them exhibited resistance for 11 antibiotics used in this study. Plasmid profile analysis of the isolates with antibiotic resistance revealed that 55.1% of them retained plasmids of 24 different types. However, no clear inter-relationship between the resistance and the plasmid profile has been observed.

• Korean Journal of Veterinary Research
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• v.26 no.2
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• pp.283-292
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• 1986

Isolation and identification of Mycoplasma were performed to clarify Mycoplasma infection of mice fed by conventional feeding at two ($K_1$, $K_2$) institutes in Korea. The twenty mice to be tested were randomly sampled from each of 10 breeding colonies in respective institute. Identification of the Mycoplasma strains isolated from the nasal cavity, lung and synovia of mice was made according to the morphology of colonies, biological and biochemical properties with special reference to M. pulmonis, M. arthrotodis and M. neurolyticum. In addition, growth inhibition test was performed using hyperimmune rabbit antisera to the strain PG-22 of M. pulmonis, the strain PG-6 of M, arthritidis and the strain PG-28 of M. neurolyticum and also differentiation of isolates from L-form bacteria was dont by Dieses staining and culture method with passage of the isolates on liquid media eliminated antibacterial drug. On the other hand, a total of 13 strains out of the 44 isolated M. pulmonis from mice was investigated for their susceptibility against 16 antibiotics in vitro. The antibiotic sensitivity test was made using $3{\times}10^4$ organisms/0.3ml on each plate(90mm diameter) with antibiotic mono-or tri-disk. The results obtained are summarized as follows: 1. Out of 20 mice from 10 breeding colonies in Kl institute, mycoplasma-like strains from the nasal cavity of 16 mice(80%) and from the lung of 8 mice(40%) were isolated, while out of 20 mice in K2 institute, M-like strains were isolated from the nasal cavity of 14 mice(70%) and from the lung of 6 mice(30%). However, no mycoplasma-like organisms were isolated from the synovia of the 40 mice examined. All the 44 strains isolated were identified as the organisms of M. pulmonis. 2. Out of the 16 antibiotics tested, penicillin, oleandomycin and bacitracin showed no activity against all the 13 M. pulmonis strains. On the contrary, lincomycin, clindamycin, chloramphenicol, tetracycline, minocycline, kanamycin, gentamycin and tobramycin showed high activity with three different antibiotic concentration of tridisk, but amikasin and spiramycin showed intermediate activity. Other antibiotics such as polymyxin B and colistin showed low activity, while erythromycin showed lower activity than others.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.714-720
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• 2012

To evaluate the antibiotic risk of $Enterococcus$ in fermented soy paste, $Enterococcus$ spp. were isolated and identified from 31 $Cheongkukjang$ and 17 $Doenjang$, samples. Exactly 123 $Enterococcus$ spp., 119 from $Cheongkukjang$ and four from $Doenjang$, were ultimately isolated. The most frequently collected $Enterococcus$ isolates in $Cheongkukjang$ were 69 strains of $E.$ $faecium$ and 20 strains of $E.$ $faecalis$. All four $Enterococcus$ spp. from $Deonjang$ were identified as $E.$ $faecium$. All isolates were sensitive to ampicillin, chloramphenicol, penicillin, and tetracyclin $E.$ However, they showed broad spectra from sensitivity to resistance to erythromycin, ripampin, and streptomycin. Vancomycin minimum inhibition concentration (MIC) of $Enterococcus$ spp. from $Cheongkukjang$ ranged from 0.25 to 8 ${\mu}g/mL$. Almost all strains were sensitive to vancomycin, but eight strains showed intermediate resistance to vancomycin. Seventeen strains showing the highest MIC of 8 ${\mu}g/mL$ among all isolates were evenly distributed among $E.$ $faecalis$, $E.$ $faecium$, $E.$ $gallinarum$, and $E.$ $casselifalvus$, in which the strong resistant genes of $van$A and $van$B for vancomycin were not detected. Overall antibiotic resistance of $Enterococcus$ isolates was relatively low and particularly low vancomycin resistance was similar to those of $Enterococcus$ isolates obtained from other foods. Therefore, the antibiotics resistance of $Enterococcus$ and especially vancomycin-resistant $Enterococcus$ spp. from $Cheongkukjang$ and $Doenjang$, is not hazardous.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.428-436
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• 2016

The emergence of antibiotic-resistant bacteria has been increased and become a public health concern worldwide. Many bacterial infections can be sequentially treated with different types of antibiotics. Thus, this study was designed to evaluate the changes in survival, antibiotic susceptibility, mutant frequency, ${\beta}$-lactamase activity, biofilm formation, and gene expression in Klebsiella pneumoniae after exposure to sequential antibiotic treatments of ciprofloxacin and meropenem. Treatments include control (CON; no addition), 1/2 MIC ciprofloxacin addition (1/2CIP), 2 MIC ciprofloxacin addition (2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC ciprofloxacin (16 h-incubation) (1/2CIP-1/2MER-2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC meropenem (16 h-incubation) (1/2CIP-1/2MER-2MER), and initial 1/2 MIC ciprofloxacin addition followed by 2 MIC ciprofloxacin(8 h-incubation) and 2 MIC meropenem(16 h-incubation) (1/2CIP-2CIP-2MER). No growth of K. pneumoniae was observed for the 2CIP throughout the incubation period. The numbers of planktonic cells varied with the treatments (7~10 log CFU/ml), while those of biofilm cells were not significantly different among treatments after 24-h incubation, showing approximately 7 log CFU/ml. Among the sequential treatments, the least mutant frequency was observed at the 1/2CIP-1/2MER-2CIP (14%). Compared to the CON, 1/2CIP-2CIP-2MER decreased the sensitivity of K. pneumoniae to piperacillin, cefotaxime, and nalidixic acid. The highest ${\beta}$-lactamase activity was 22 nmol/min/ml for 1/2CIP-1/2MER-2CIP, while the least ${\beta}$-lactamase activity was 6 nmol/min/ml for 1/2CIP-2CIP-2MER. The relative expression levels of multidrug efflux pump-related genes (acrA, acrB, and ramA) were increased more than 2-fold in K. pneumoniae exposed to 1/2CIP-1/2MER-2MER and 1/2CIP-2CIP-2MER. The results suggest that the sequential antibiotic treatments could change the antibiotic resistance profiles in K. pneumoniae.