• Tuberculosis and Respiratory Diseases
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• v.78 no.3
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• pp.196-202
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• 2015

Background: Viridans streptococci (VS) are a large group of streptococcal bacteria that are causative agents of community-acquired respiratory tract infection. However, data regarding their clinical characteristics are limited. The purpose of the present study was to investigate the clinical and radiologic features of community-acquired pneumonia (CAP) with or without parapneumonic effusion caused by VS. Methods: Of 455 consecutive CAP patients with or without parapneumonic effusion, VS were isolated from the blood or pleural fluid in 27 (VS group, 5.9%) patients. Streptococcus pneumoniae was identified as a single etiologic agent in 70 (control group) patients. We compared various clinical parameters between the VS group and the control group. Results: In univariate analysis, the VS group was characterized by more frequent complicated parapneumonic effusion or empyema and bed-ridden status, lower incidences of productive cough, elevated procalcitonin (>0.5 ng/mL), lower age-adjusted Charlson comorbidity index score, and more frequent ground glass opacity (GGO) or consolidation on computed tomography (CT) scans. Multivariate analysis demonstrated that complicated parapneumonic effusion or empyema, productive cough, bed-ridden status, and GGO or consolidation on CT scans were independent predictors of community-acquired respiratory tract infection caused by VS. Conclusion: CAP caused by VS commonly presents as complicated parapneumonic effusion or empyema. It is characterized by less frequent productive cough, more frequent bed-ridden status, and less common CT pulmonary parenchymal lesions. However, its treatment outcome and clinical course are similar to those of pneumococcal pneumonia.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.684-692
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• 2016

Acute respiratory virus infectious diseases are a growing health problem, particularly among children and the elderly. Much effort has been made to develop probiotics that prevent influenza virus infections by enhancing innate immunity in the respiratory tract until vaccines are available. Lactobacillus plantarum GB-LP2, isolated from a traditional Korean fermented vegetable, has exhibited preventive effects on influenza virus infection in mice. To identify the molecular basis of this strain, we conducted a whole-genome assembly study. The single circular DNA chromosome of 3,284,304 bp was completely assembled and 3,250 protein-encoding genes were predicted. Evolutionarily accelerated genes related to the phenotypic trait of anti-infective activities for influenza virus were identified. These genes encode three integral membrane proteins, a teichoic acid export ATP-binding protein and a glucosamine - fructose-6-phosphate aminotransferase involved in host innate immunity, the nonspecific DNA-binding protein Dps, which protects bacteria from oxidative damage, and the response regulator of the three-component quorum-sensing regulatory system, which is related to the capacity of adhesion to the surface of the respiratory tract and competition with pathogens. This is the first study to identify the genetic backgrounds of the antiviral activity in L. plantarum strains. These findings provide insight into the anti-infective activities of L. plantarum and the development of preventive probiotics.

• YAKHAK HOEJI
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• v.40 no.1
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• pp.95-101
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• 1996

The in vitro antibacterial activities of LB10522, a new catechol-substituted cephalosporin, were compared with those of cefpirome, ceftazidime, ceftriaxone, and cefoperaz one against clinical isolates and laboratory standard anaerobes. LB10522 had broad spectrum antibacterial activities against both gram-positive and gram-negative microorganisms. It was most active against gram-positve bacteria among the reference cephalosporins tested. Against gram-negative strains such as the family Enterobacteriaceae, LB10522 showed an activity comparable to that of cefpirome. But LB10522 was more potent than ceftazidime, ceftriaxone and cefoperazone. In particular, Pseudomonas aeruginosa was highly susceptible to LB10522, which was 32-fold and 64-fold more active than ceftazidime and cefpirome, respectively. Against anaerobic strains, the activity of LB10522 was similar to those of reference compounds. LB10522 exhibited potent therapeutic activities against experimental local infections in mice. The therapeutic effect of LB10522 against urinary tract infection (UTI) caused by P. aeruginosa 1912E in mice was superior to that of cefpirome. Against experimental respiratory tract infection (RTI) caused by K. pneumoniae DT-S in mice, LB10522 was as effective as cefpirome. The in vivo efficacy of LB10522 was correlated well with its in vitro activity.

• Biomolecules & Therapeutics
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• v.7 no.1
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• pp.44-53
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• 1999

The resistant strains due to the extended-spectrum $\beta$-lactamase (ESBL) were susceptible to cefatrizine combined with clavulanic acid. The purpose of this study was to evaluate the in vitro and in vivo antibacterial activities of cefatrizine/clavulanic acid (CTRZ/CV) combination at a ratio of 2 : 1 in comparison with cefaclor (CCLO), cefuroxime (CRXM), cefuroxime axetil (CRXMA) and amoxicillin/clavulanic acid (AMXCCV). CTRZ/CV showed good activity against laboratory strains of gram-positive and gram-negative bacteria and exhibited excellent antibacterial activity against $\beta$-lactamase-producing strains. The bactericidal activity of CTRZ/CV was superior to that of CCLO and CRXM, and almost equal to that of AMXCCV against the $\beta$-lactamase-producing strains. The in vitro results were substantiated. by in vivo mouse experimental infection studies with $\beta$-lactamase-producing and non-producing strains. In mixed experimental infection due to $\beta$-lactamase-producing and non-producing strains, the therapeutic efficacy of CTRZ/CV was superior to that of CTRZ, CCLO, CRXMA and AMXCCV. In respiratory tract infection in mice due to Klebsiella pneumoniae EB4O, CTRZ/CV was more erective than CCLO, CRXMA and AMXCCV and also more efficacious than CCLO, CRXMA and AMXCCV in urinary tract infection in mice due to Escherichia coli EB13. These results indicate that CTRZ/CV is a useful drug for the treatment of infection caused by $\beta$-1actamase-producing strains including ESBL-producing strains.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1585-1591
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• 2010

A comprehensive study on the production of inflammatory mediators in the lungs of BALB/c mice following infection with Stenotrophomonas maltophilia was conducted. The levels of pro-inflammatory cytokines, tumor necrosis factor alpha (TNF-${\alpha}$), and interleukin-1${\beta}$ (IL-1${\beta}$) were raised in the lungs of infected mice compared with control. The production of anti-inflammatory cytokine IL-10 was slightly delayed. Its peak level was on the $2^{nd}$ day, whereas the peak of pro-inflammatory cytokines was observed on day 1 after intranasal challenge. This was accompanied by a rise in myeloperoxidase (MPO) and malondialdehyde (MDA) on day 1. The increase in MPO levels matched with histopathological observations, as neutrophils infiltration was detected on the first day. Alveolar macrophages (AMs) obtained from infected animals showed a higher rate of uptake and killing when exposed to bacteria in vitro, compared with similar experiments conducted with AMs from normal mice (control). This suggests that AMs were more efficient in cleaning the bacteria. The nitric oxide (NO) production however started early during infection but reached its maximum on the $3^{rd}$ day. No mortality was observed among the infected animals, and infection was resolved by the $5^{th}$ day post infection. No drastic changes in the lung tissue were observed on histopathological examination.

• The Journal of the Korean Society for Microbiology
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• v.20 no.1
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• pp.73-77
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• 1985

Haemophilus aphrophilus is a fastidious gram-negative bacillus found in mouth of normal individuals. Though H. aphrophilus infection is quite rate, it includes such serious ones as endocarditis and brain abscess. The authors isolated H. aphrophilus from five patients with the diagnosis of lung abscess, conjunctivitis, brain abscess and facial masticator space abscess. Two of the patients died. Three of the patients also yielded other species of bacteria from the same specimens. One of the isolate was intermediately susceptible to amikacin and resistant to tobramycin, indicating the necessity of a routine susceptibility test in order to select the proper antimicrobial agents. Since H. aphrophilus can be differentiated from other similar organisms by morphological and biochemical characteristics, one should determie the possibility of this organism when fastidious gram-negative bacilli are isolated from blood or from sites adjacent to upper respiratory tract.

• International Journal of Oral Biology
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• v.41 no.2
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• pp.75-81
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• 2016

Human mouth environment is known to include a variety bacteria, including Streptococcus spp., Staphylococcus spp., Actinomyces spp., Lactobacillus spp., Candida spp., Enterobacteriaceae, et al. Human oral microorganisms can cause dental caries, gingivitis, periodontitis, respiratory tract infection, and cardiovascular disease. Thus, right denture cleaning is essential to oral and general human health. The aim of this study was to evaluate the bactericidal effect of a sodium dichloroisocyanurate-based effervescent tablet (Aos Denti Germ, Aos Company, Chungbuk, Korea) against oral microorganisms. A total of 5 species Streptococcus spp. (Streptococcus anginosus, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, and Streptococcus sobrinus), Actinomyces oris, Candida albicans, and Escherichia coli were used in this study. All strains were exposed to the distilled water prepared with effervescent tablet. After the exposure, the mixture of strains and effervescent tablet was inoculated onto blood agar or MacConkey agar plate and cultured at $36^{\circ}C$. All strains were killed immediately on exposure to effervescent tablet. The results suggested that effervescent tablet could be used as an effective denture cleanser for dental hygiene.

• Clinical and Experimental Pediatrics
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• v.52 no.12
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• pp.1358-1363
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• 2009

Purpose:The aim of this study was to determine the prevalence of asymptomatic nasopharyngeal carriages in children using a multiplex reverse transcriptase-polymerase chain reaction (mRT-PCR) assay kit. Methods:We obtained nasopharyngeal swabs from 33 children without any underlying disease from July 25 to July 28, 2008. The children were free from the signs of respiratory tract infections at the time of sampling. DNA was extracted from the swabs and subjected to multiplex RT-PCR using a primer set for the detection of pneumococci ($Seeplex^{(R)}$ PneumoBacter ACE Detection Seegene, Seoul, Korea). The amplified PCR products were separated on 2% agarose gels and stained with either ethidium bromide or screen tape system (Lab901 Scotland, UK). Results:A total of 33 children (male, 15 female, 18) aged between 3.2 and 16.3 (median, 8.2) years were included in this study. The mRT-PCR detected colonized bacteria (Streptococcus pneumoniae, Hemophilus influenzae, Chlamydia pneumoniae, and Bordetella pertussis) in 30 children (90.9%). Of these, 13 children (39.4%) showed more than 2 bacteria: 12 children were positive for 2 bacteria (S. pneumoniae and H. influenzae) and 1 child was positive for 3 bacteria (S. pneumoniae, H. influenzae, and C. pneumoniae). Conclusion:mRT-PCR was found to be a sensitive tool for the detection of asymptomatic nasopharyngeal carriages. Clinical significances of the bacteria detected by mRT-PCR will have to be evaluated in the future.

• Clean Technology
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• v.29 no.2
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• pp.135-144
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• 2023

Pseudomonas aeruginosa and Staphylococcus aureus are the two most frequently encountered pathogens responsible for chronic wound infections, often coexisting in such cases. These infections exhibit heightened virulence compared to single infections, leading to unfavorable patient outcomes. The interaction among microorganisms within polymicrobial infections has been shown to exacerbate disease progression. Polymicrobial infections, prevalent in various contexts such as the respiratory tract, wounds, and diabetic foot, typically involve diverse microorganisms, with Pseudomonas aeruginosa and Staphylococcus aureus being the most commonly identified pathogens. This study aimed to compare the growth patterns of bacteria under a concentration gradient of toxic chemicals, focusing on a Gram-negative strain of Pseudomonas aeruginosa and a Gram-positive strain of Staphylococcus aureus. The minimum inhibitory concentration (MIC), which signifies the concentration at which bacterial growth is inhibited, was determined by performing broth microdilution and assessing the bacteria's growth curves. The growth curves of both Pseudomonas aeruginosa and Staphylococcus aureus were confirmed, and the exponential growth phases were applied to calculate the doubling times of bacteria. The MIC value for each toxic chemical was determined through broth microdilution. These results allowed for the identification of disparities in growth rates between Gram-positive and Gram-negative bacteria, as well as differences in resistance to individual toxic substances. We expect that this approach has a strong potential for further development towards the innovative treatment of bacteria-associated infections.

• Journal of Life Science
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• v.25 no.12
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• pp.1399-1407
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• 2015

Klebsiella pneumoniae is found in the normal flora of the skin, mouth, respiratory tract, urinary tract, and intestines in human. However, the stain is opportunistic pathogen, which is the causative agent of community acquired pneumonia. Corn silk has been known to be effective for antimicrobial activity against pathogenic bacteria, including K. pneumoniae, Staphylococcus aureus, Bacillus subtilis, Shigella spp., Salmonella spp., Escherichia coli, Pseudomonas aeruginosa, et al. In this study we focused on the antimicrobial properties of con silk water extract of K. penumoniae. K. pneumoniae isolates K. pneumoniae ATCC 13883 and broad-spectrum β-lactamase (BSBL), exteded-spectrum β-lactamase (ESBL), carbapenemase-producers. Antimicrobial susceptibilities were determined by the disk diffusion method. Searches for bla genes were performed by PCR amplication and direct sequencing. MacConkey agar plate medium was prepared using the corn silk extracts (50% or 100%) instead of distilled water for antimicrobial activity test. The microbial growth inhibitory potential of K. pneumoniae was determined by using the MacConkey agar plate spreading method, and the plate was incubated 18 hr at 37℃. Genes encoding β-lactamases including SHV-1 (n=8), SHV-2a (n=8), SHV-5 (n=2), SHV-11 (n=2), SHV-12 (n=18), TEM-1 (n=10), CTX-M-3 (n=2), CTX-M-14 (n=2), CTX-M-15 (n=1), GES-5 (n=5), KPC-2 (n=6), KPC-3 (n=4), and NDM-1 (n=2) were detected. The corn silk extract showed significantly antimicrobial activity against K. pneumoniae ATCC 13883, but BSBLs, ESBLs, and carbapenemase producers were not. Therefore, corn silk extract is thought to be able to assist in the prevention and rapid recovery of infectious disease caused by K. pneumoniae.