• 대한수의학회지
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• 제47권1호
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• pp.77-84
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• 2007

Helicobacter pylori (H. pylori) is an important bacterial pathogen that causes chronic gastritisand is associated with gastroduodenal ulcer disease, adenocarcinoma of the distal stomach, and gastricH. pylori infection associated with host agehave not been well-defined in human. To evaluate the difference in host susceptibility to infection in relationto age of acquisition of H. pylori infection, we designed an experiment involving inoculation of H. pyloriATC 43504 at different ages of Mongolian gerbils. H. pylori was inoculated at 5 weeks and 18 monthsof age, as representatives of early and late infection, respectively. Animals were sacrificed 1 week and 4weeks after challenge, and the stomach was removed from each animal for bacterial culture, histologicalexamination, and polymerase chain reaction test. 5 week-old gerbils revealed infection andmaintained continuously its infection until 4 weeks. However, old gerbils did not maintained H. pyloriinfection. These data suggest the insusceptibility of H. pylori in old Mongolian gerbils and the importanceof animal ages for successful animal experimental infection. Also, the results demonstrated that earlyinfection of H. pylori increases its host susceptibility, as compared to the case with later infection, possiblybecause of differences in host gastric mucosal factors and imunologic responses.

• 기본간호학회지
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• 제22권3호
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• pp.268-276
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• 2015

Purpose: The purpose of this study was to identify factors which influence the management of MultiDrug -Resistant Organisms (MDROs) by nurses in Intensive Care Units (ICUs). Methods: Data were collected from December 8 to 20, 2013 and participants were 163 ICU nurses working in one general hospital. The Health Belief Model tool and knowledge and management of MDROs infection tools were used in the study. Descriptive statistics, t-test, analysis of variances, Pearson correlation coefficients and multiple regression were used to analyze the data. Results: Knowledge, perceived susceptibility, and perceived benefits had a significant influence on MRSA (Methicillin Resistant Staphylococcus Aureus,) and MDRAB (Multidrug Resistant Acinetobacter Baumannii) infection management when all the other variables were considered. Significant variable which had influence on VRE (Vancomycin Resistant Eenterococci) infection management were perceived susceptibility and perceived benefits. Conclusion: Perceived susceptibility and perceived benefits had significant influence on MDROs infection management. Emphasis needs to be on the perceived susceptibility and perceived benefits of MDROs infection management when providing an educational program for ICU nurses.

• Journal of Veterinary Science
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• 제22권3호
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• pp.36.1-36.12
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• 2021

Background: Mouse hepatitis virus (MHV) A59 is a highly infectious pathogen and starts in the respiratory tract and progresses to systemic infection in laboratory mice. The complement system is an important part of the host immune response to viral infection. It is not clear the role of the classical complement pathway in MHV infection. Objectives: The purpose of this study was to determine the importance of the classical pathway in coronavirus pathogenesis by comparing C1qa KO mice and wild-type mice. Methods: We generated a C1qa KO mouse using CRISPR/Cas9 technology and compared the susceptibility to MHV A59 infection between C1qa KO and wild-type mice. Histopathological and immunohistochemical changes, viral loads, and chemokine expressions in both mice were measured. Results: MHV A59-infected C1qa KO mice showed severe histopathological changes, such as hepatocellular necrosis and interstitial pneumonia, compared to MHV A59-infected wild-type mice. Virus copy numbers in the olfactory bulb, liver, and lungs of C1qa KO mice were significantly higher than those of wild-type mice. The increase in viral copy numbers in C1qa KO mice was consistent with the histopathologic changes in organs. These results indicate that C1qa deficiency enhances susceptibility to MHV A59 systemic infection in mice. In addition, this enhanced susceptibility effect is associated with dramatic elevations in spleen IFN-γ, MIP-1 α, and MCP-1 in C1qa KO mice. Conclusions: These data suggest that C1qa deficiency enhances susceptibility to MHV A59 systemic infection, and activation of the classical complement pathway may be important for protecting the host against MHV A59 infection.

• The Plant Pathology Journal
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• 제36권5호
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• pp.398-405
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• 2020

Nutrient manipulation is a promising strategy for controlling plant diseases in sustainable agriculture. Although many studies have investigated the relationships between certain elements and plant diseases, few have comprehensively explored how differing mineral nutrition levels might affect plant-fungal pathogen interactions, namely plant susceptibility and resistance. Here, we systematically explored the effects of the seven mineral elements that plants require in the greatest amounts for normal development on the susceptibility of soybean plants (Glycine max) to Fusarium oxysporum infection in controlled greenhouse conditions. Nitrogen (N) negligibly affected plant susceptibility to infection in the range 4 to 24 mM for both tested soybean cultivars. At relatively high concentrations, phosphorus (P) increased plant susceptibility to infection, which led to severely reduced shoot and root dry weights. Potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), and iron (Fe) induced plant resistance to infection as their concentrations were increased. For K and Ca, moderate concentrations had a positive effect on plant resistance to the pathogen, whereas relatively high doses of either element adversely affected plant growth and promoted disease symptoms. Further experiments were conducted, assessing disease suppression by selected combinations of macro-elements and Fe at screened concentrations, i.e., K (9 mM) plus Fe (0.2 mM), and S (4 mM) plus Fe (0.2 mM). The disease index was significantly reduced by the combination of K plus Fe. In conclusion, this systematic investigation of soybean plant responses to F. oxysporum infection provides a solid basis for future environmentally-friendly choices for application in soybean disease control programs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권4호
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• pp.322-328
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• 2005

Oral and maxillofacial infections are most commonly odontogenic in origin. The present study was implemented for patients with oral and maxillofacial infections in order to determine what differences were present in cultured bacteria, depending upon the different types of infection. For the present study, the epidemiological characteristics, the state of infection, and the results of the pus culture and antibiotic susceptibility tests were analyzed for the 159 cases where pus culture tests were performed. The patients were treated at the Oral and Maxillofacial Surgical Department of Chonnam National University Hospital during an 18-months period from March 2003 to August 2004. Among the total 159 pus culture specimens, bacteria were cultured in 111 cases (69.8%). In the 111 pus culture specimens, Streptococcus species, Neisseria species, and Staphylococcus species were cultured from 69 cases (51.1%), 21 cases (15.6%), and 15 cases (11.1%), respectively and were determined to be bacterial strains the predominant bacteria responsible for oral and maxillofacial infectious diseases. Twenty four cases (15.1%) among the 159 specimens showed mixed infections. The mostly isolated bacteria from each of the space abscess, dentoalveolar abscess, inflammatory cyst, and pericoronitis cases were the Viridans streptococci. There was little relevance between the type of infection and the type of cultured bacteria. Antibiotic susceptibility tests showed a high level of susceptibility to teicoplanin(100%), vancomycin(100%), chloramphenicol(96.4%), ofloxacin(88.3%), imipenem(83.3%), erythromycin(82.5%) and a low susceptibility to cefazolin(40.0%), oxacillin(44.7%), ampicillin(49.4%), penicillin(51.1%). These results indicate that there was no significant difference among the cultured bacteria depending on the type of infections and their susceptibility to cephalosporin and penicillin G was low.

• Journal of Microbiology and Biotechnology
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• 제19권7호
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• pp.734-741
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• 2009

Recently, strains of methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin (VCM) have been clinically isolated. The antibacterial activity of a new drug, linezolid (LZD), in such a strain was evaluated by measuring bacterial metabolic activity. A total of 73 MRSA strains having various susceptibilities to VCM were subjected to a novel and highly sensitive chemiluminescence-based assay. LZD MIC in the tested strains, measured by the microbroth dilution method, was within the range 1-4 mg/l (mostly ${\leq}2$mg/l), except for one LZD-resistant strain (NRS127; MIC=7 mg/l), and showed no correlation with VCM resistance. The chemiluminescence assay demonstrated that bacterial metabolic activity was strongly suppressed with increasing LZD concentration. The chemiluminescence intensity curve had a low baseline activity without tailing in most strains. The present results suggest that LZD has strong antibacterial activity against MRSA strains, and would be effective for treatment of infections that are poorly responsive to VCM. The chemiluminescence assay facilitated sensitive and discriminative susceptibility testing within a relatively short time.

• 대한치과의사협회지
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• 제54권5호
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• pp.356-364
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• 2016

Aim: The purpose of this study was to identify dominant pathogens and their antimicrobial susceptibilities of endodontic infection in type II diabetes mellitus (DM) patients to determine effective empirical antibiotics. Methodology: Pathogens from endodontic infection in six patients with DM and in six patients without DM were cultured, identified and their antimicrobial susceptibility was tested using Vitek2 systems ($bioM{\acute{e}}rieux$, Marcy l' Etoile, France). The results were analyzed using Chi-square test and Fisher's exact test at P< 0.05 level. Results: Pathogens of opportunistic infection were dominant in DM patients (P=0.015). However, there was no significant difference of antimicrobial susceptibility between DM and non-DM patients. Relatively high percent (27%) of pathogens showed resistance to penicillin. Conclusions: More cautions should be paid to DM patients because they are prone to opportunistic infection. Penicillin is not effective in the control of endodontic infection.

• 한국임상수의학회지
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• 제20권2호
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• pp.177-184
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• 2003

The present study was conducted to investigate isolation and antimicrobial drug susceptibility of clinical mastitic milking total 610 (897 quaters) dairy cattles from 36 dairy farms in Gyeongnam south area (Cosung, Masan) during the period from March 1999 to August 2002. The results obtained were summerized as follows . 1. Incidence of bacterial infection in four quaters was showed that right anterior quarter was 178(19.8%), right posterior quarter was 292(32.6%), left anterior quarter was 148 (16.2%), and left posterior quarter was 279 (31.1%), respectively. Isolation rate of posterior two quarters was higher 2 times than anterior two quarters. 2. Incidence of double infections of 897 clinical mastitic milk were showed that single infection was 549 (61.2%), double infection was 167(18.6%), triple infection was 9(1%) and no isolation was 172(19.2%). 3. Isolation of infected etiologic bacteria was showed that Streptococci spp., was 267(31%), Staphylococci spp., was 267(41%), S aureus, was 48(5.6%), G(-) bacillus was 126(5.6%), and Corynebactrium spy. was 52(6%), respectively, from total 861 samples. 4. The results of antimicrobial drug susceptibility of all isolates were showed that Streptococci spp., Staphylococci spp., S aureus, (G)(-) bacillus, and Corynebactrium spp. were susceptible to cefuroxime, cefoperazone, amoxicillin, cefazolin, ampicilin, penicillin, gentamicin, erythromycin, cloxacilin, ciprofloxacin, sulfamethoxasole/trimetoprim, teteracyclin, and norfloxacin (> 70%), but some of them were resistant to neomycin, streptomycin colistin, and cephalothin(> 60). 5. The results of drug susceptibility obtained from each farms had different susceptibility, even though, etiological microorganisms were same in each farms.

• Childhood Kidney Diseases
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• 제10권2호
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• pp.192-200
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• 2006

Purpose : This study was performed to identify longitudinal changes in the prevalence of organisms isolated from urinary tract infection(UTI) and in the pattern of Escherichia coli susceptibility to antibiotics during the past 10 years in children with UTI. Methods : We performed a retrospective study of a total of 192 urine cultures from children with UTI in the Department of Pediatrics, Seoul Adventist Hospital over two periods(1st: 1995-2000, 2nd:2001-2005). Antimicrobial susceptibility of the isolates was compared between the two groups. Results : The pathogens of UTI in the two groups were similar. In the first period, E. coli was the leading uropathogen(66.2%) followed by Klebsiella pneumoniae(7.8%), Enterobacter cloacae(6.5%), and others(19.5%). In the second period, E. coli was the leading uropathogen(67%) followed by K. pneumoniae(12.2%), E. cloacae(3.5%), Enterobacter aerogenes(3.5%), and others(13.8%). The susceptibility pattern of E. coli to amoxicillin/clavulanate(87.5%, 81.0%) did not present any statistically significant difference between the two periods(P>0.05). The susceptibility of E. coli to TMP/SMX(52.4%, 50.0%) was still low with no significant difference between the two periods(P>0.05). Conclusion : Our results suggest that the use of amoxicillin/clavulanate is still an excellent therapeutic option in children with UTI. The low rate of susceptibility to TMP/SMX against uropathogens suggest that TMP/SMX may be reevaluated as the first-line therapeutic drug for UTI.

• 한국식물병리학회지
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• 제10권2호
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• pp.140-143
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• 1994

Comparison of susceptibility of asparagus (Asparagus officinalis L.) seedlings and plantlets to different fusarial species was made to determine whether in vitro propagated asparagus plantlets can be used as a substitute for seedlings in histopathological study on the infection processes of Fusarium species to asparagus. Fusarium oxysporum was isolated most frequently (50% of the total) from lesions of root and crown rot of asparagus cultivated in the field followed by F. moniliforme (8.8% of the total) and F. solani (2.9% of the total). Plantlets and seedlings of all asparagus were susceptible to f. moniliforme and F. oxysporum isolates, but those were not susceptible to both avirulent F. oxysporum (AVFO) and F. solani in pathogenicity tests. Overall, there were no differences between seedlings and plantlets in the susceptibility to virulent fusarial infections. In vitro propagated asparagus plantlets, therefore, could be used as a substitute for seedlings in histopathological study on the infection processes of Fuasrium species to asparagus.