• Journal of Microbiology
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• v.43 no.5
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• pp.398-405
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• 2005

Polyamines such as putrescine are small, ubiquitous polycationic molecules that are required for optimal growth of eukaryotic and prokaryotic cells. These molecules have diverse effects on cell physiology and their intracellular content is regulated by de novo synthesis and uptake from the environment. The studies presented here examined the structure of a putative polyamine transporter (Pot) operon in Streptococcus pneumoniae (pneumococcus) and growth of pneumococci in medium containing putrescine substituted for choline. RT-PCR experiments demonstrated that the four genes encoding the Pot system are co-transcribed with murB, a gene involved in an intermediary step of peptidoglycan synthesis. Pneumococci grown in chemically-defined media (CDM) containing putrescine without choline enter logarithmic phase growth after 36-48 hs. However, culture density at stationary phase eventually reaches that of choline-containing medium. Cells grown in CDM-putrescine formed abnormally elongated chains in which the daughter cells failed to separate and the choline-binding protein PspA was no longer cell-associated. Experiments with CDM containing radiolabeled putrescine demonstrated that pneumococci concentrate this polyamine in cell walls. These data suggest that pneumococci can replicate without choline if putrescine is available and this polyamine may substitute for aminoalcohols in the cell wall teichoic acids.

• Pediatric Infection and Vaccine
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• v.22 no.2
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• pp.97-105
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• 2015

Purpose: Serotyping pneumococcal isolates is important to monitor efficacy of pneumococcal vaccines. Because of difficulties of typing pnueumocci, a multiplex bead-based (multibead) serotyping assay was recently introduced. The aim of this study is to establish a new multibead serotyping assay and to apply this method to analyze clinical isolates of pneumococci in Korea. Methods: To establish the multibead serotyping assay, six key reagents were transferred from University of Alabama at Birmingham (UAB) to Ewha Center for Vaccine Evaluation and Study (ECVES): bead set coated with polysaccharide and monoclonal antibody pool were used in one multiplex inhibition-type immunoassay and 2 bead sets coated DNA probe and 2 primer pools were used in two multiplex PCR-based assays. After multibead serotyping assay was set up, 75 test samples of pneumococci were analyzed whether ECVES is able to identify serotype correctly. After confirming the performance, serotyping assay was applied to identify serotypes of 528 clinical isolates of pneumococci collected from 3 different hospitals. Results: After establishment of the multibead pneumococcal serotyping assay system at ECVES, 75 test samples were analyzed. There was no discrepancy of serotypes of 75 test samples between the results assigned at UAB and those at ECVES. The serotypes of 528 pneumococci isolated from patients or healthy subjects were determined in 94.3% of isolates (498/528). Conclusions: The multibead pneumococcal serotyping assay can be successfully established in Korea. With this method, surveillance of serotypes of pneumococci isolated from patients as well as healthy subjects could be studied.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.218-224
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• 1997

Purpose: The antimicrobial resistance of S. pneumoniae has encountered with increasing frequency from around the world. In our country, penicillin resistant strains of S. penumococci are rapidly increasing. It has been known that colonized pneumococci in upper respiratory tract cause sinisitis, otitis media, meningitis and pneumonia. We tried to reveal the colonization rate of pneumonocci in upper respiratory tract, their antimicrobial resistance and DNA fingerprinting pattern in normal children. Methods: We got specimens from 117 children of day-care center in Seoul through oropharyngeal swab. After incubation on BAP, optochin test and slide latex agglutination test were used for identification. Antimicobial susceptibility test to penicillin, vancomycin, erythromycin and TMP-SMZ was done with disk diffusion method. Penicillin MIC was gotten through the broth microdilution method. Genotyping of 45 pneumococci was done by rep-PCR using REP1R-Dt and REP2-Dt primer. Results: The carriage rate of pneumococci in the day-care center children was 38%(45/117). The resistance of penicillin, erhthromycin, TMP/SMZ, vancomycin by the disk diffusion method are 89%, 91%, 64% and 0%, respectively. 64% of the isolates showed multiple resistance. 7 types of DNA fingerprinting were gotten and 78% of isolates belonged to three types. Conclusion: We found that the antimicrobial resistance of children attending the day-care center in Seoul was much higher than expected. We assumed that this might be due to their easy and frequent exposure to antimicrobial agents and crowded day-care center environment.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.235-241
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• 2006

Streptococus pneumoniae is an important cause of invasive infections as well as non-invasive infections such as acute otitis media and sinusitis both in children and adults. Resistance of S. pneumoniae to multiple antimicrobials is increasing and poses therapeutic challenges, and prevention became more important. 23-valent polysaccharide vaccine has been used for the last several decades, but is not effective in children <2 years of age, the highest risk group of invasive diseases. Recently, a 7-valent pneumococcal protein conjugate vaccine(PCV) which is effective in infants and young children has been developed. The efficacy of PCVs against invasive pneumococcal disease and pneumonia is well established and is documented in several well-conducted studies. However, the effect of PCVs on otitis media is less obvious and more complex. PCVs clearly reduce diseases caused by vaccine-type(VT) pneumococci, but replacement of VT serotypes by non-VT serotypes in nasopharyngeal carriage of S. pneumoniae is responsible for the increase in acute otitis media caused by non-VT serotypes. Three years after introduction of PCV in the US, some increase of invasive infections with serotype 19A possibly due to serotype switching within certain vaccine type strains has been noted. Since most antibiotic-resistance in S. pneumoniae is confined to VT serotypes, vaccine use also reduces antibiotic resistance. With development of PCV, there was a great advance in the prevention of pneumococcal diseases, but replacement with potential virulent organisms and development of antibiotic resistance in non-VT pneumococci is a possibility that needs careful monitoring.

• The Journal of the Korean Society for Microbiology
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• v.35 no.5_6
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• pp.337-339
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• 2000

MRSA, erythromycin-resistant S. pyogenes, penicillin non-susceptible pneumococci, PPNG, ESBL-producing E. coli and K. pneumoniae, class C ${\beta}$-lactamase-producing E. coli, fluoroquinolone-resistant E. coli, aminoglycoside-resistant A. baumannii and P. aeruginosa are all prevalent in Korea, which suggest the presence of high levels of antimicrobial selective pressure and nosocomial spread of resistant bacteria. Rapid increase of VRE and emergence of fluoroquinolone-resistant gonococci and VIM-2 metallo-${\beta}$-lactamase-producing P. aeruginosa are recently observed new threats in Korea.

• Pediatric Infection and Vaccine
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• v.15 no.2
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• pp.100-107
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• 2008

Acute otitis media and acute sinusitis are some of the most common antibiotic-prescribed diseases in childhood. Usually, with an accurate diagnosis, a 10-14 day course of antibiotics is recommended to cover common causative agents, including pneumococci. Establishment of management guidelines for these infectious diseases based on further study of the epidemiologic profile, antibiotic resistance, and clinical circumstances in Korea is needed.

• Korean Journal of Microbiology
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• v.38 no.1
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• pp.38-44
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• 2002

Pneumococcal surfacce protein A (PspA) is an important virulence factor and an antigenically variable surface protein of the pneumococci. To purify the PspA from S. pneumoniae KNIH1156 , a clinical isolate (type 19F), we have taken advantage of the fact that PspA is released from the surface of pneumococci into the medium by growing in a CDM-ET medium and PspA is capable of binding human lactoferrin, the iron carrier protein. PspA of S. pneumoniae KNIH1156 was purified from culture supernatant by human lactoferrin (hLf) affinity chromatography. The purified PspA was confirmed with anti-PspA antiserum and also had the binding capacity to hLf specifically. To determine whether the purified PspA could elicit protection in mice against pneumococcal inflection, we immunized the mice with purified PspA and subsequently challenged with S. pneumoniae KNIH1156. Immunization with purified PspA protected mice from 500 times the $LD^{50}$ of S. pneumoniae KNIH1156. Therefore, it has been shown that purified PspA fromS. pneumoniae KNIH1156 (type 19F) is a protective immunogen.

• Proceedings of the Microbiological Society of Korea Conference
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• 2009.05a
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• pp.38-39
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• 2009

• Journal of Animal Science and Technology
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• v.64 no.5
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• pp.1008-1011
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• 2022

We here report the whole genome sequence of Ligilactobacillus agilis C7 with anti-listerial activity, which was isolated from pig feces. The genome size of L. agilis C7 (~ 3.0 Mb) is relatively larger compared with other L. agilis strains. L. agilis C7 carries three bacteriocin gene clusters encoding garvicin Q, salivaricin A, and Blp family class II bacteriocin. Garvicin Q and salivaricin A are reported to be active against Listeria monocytogenes and Micrococcus luteus, respectively, as well as against other Gram-positive bacteria. Meanwhile, the bacteriocin encoded in the blp cassette was shown to be active against pneumococci, mediating intraspecies competition. This report highlights the potential of L. agilis C7 for the production of bacteriocins inhibiting pathogenic bacteria.

• Pediatric Infection and Vaccine
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• v.10 no.1
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• pp.81-86
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• 2003

Purpose : Streptococcus pneumoniae remains a leading cause of meningitis, sepsis, pneumonia, and otitis media in children worldwide. Emergence of drug-resistant organism has substantially complicated the therapy of these infections. This study was conducted to determine the clinical features and changing patterns of antibiotic-resistant rates of Streptococcus pneumoniae. Methods : We have retrospectively examined 306 cases of culture proven patients who were admitted to the Department of Pediatrics, Severance hospital, from the year 1991 to year 2000. The type of culture specimen used, presence of penicillin resistance, characteristics according to various presenting diseases and their prevailing year were also examined. Results : The mean age of cases was 7.9 year and the ratio of male to female was 1.6 : 1. The main age group of pneumococcal infection was under 2 years(42%). Systemic infections associated with pneumococci were sepsis(19.3%) and meningitis(9.5%), while local infections presented as pneumonia(29.2%), otitis media(19.3%), exudative tonsillitis(13.3%), and sinusitis(9.2%) in the order of frequency. Seasonal variation was seen in the incidence of pneumococcal infection: high incidence of infection was seen in Spring(Mar.~Apr; 32%), while the incidence was low during summer(Aug.~Sep.; 6%). Penicillin-resistant rate of pneumococci was steadily on the increase since the year 1991(65%) to year 2000(84%). Conclusion : Antibiotic-resistant pneumococci increased during the past decade. For effective prevention of pneumococcal infections, national survey of pneumococcal infections and expanded use of pneumococcal vaccination would be needed.