• Pediatric Infection and Vaccine
• /
• v.18 no.1
• /
• pp.97-102
• /
• 2011

The Multidrug-resistant Acinetobactor baumanii (MDRAB) is an opportunistic pathogen. Patients with long periods of hospital stay and/or under intensive care unit (ICU) receiving invasive management are more susceptible to this pathogen. In this report, four children with MDRAB infection are reviewed and described their clinical characteristics. There had been concurrent outbreaks of MDRAB infection in adult patients in the ICU at this period of time. The first child had received a craniotomy and epidural hematoma evacuation. The second child was admitted for status epilepticus with hydrocephalus. The third child had pneumonia with status epilepticus with hydrocephalus. The fourth child had poor activity due to hypoxic ischemic encephalopathy and convulsive disorder. Except the fourth child, all had not been exposed to carbapenem prior to infection of MDRAB. That imply the cause of MDRAB infections may be associated with invasive management and prolonged hospitalization together with the previous exposure to carbapenem in our cases. We would like to emphasize the importance and minimizing the spread of hospital infection in patients under prolonged intensive care management regardless of the use of carbapenem.

• Microbiology and Biotechnology Letters
• /
• v.31 no.1
• /
• pp.90-93
• /
• 2003

The antibacterial activity of chitosan-alginate-Fe(II) complex (CAFC) against Escherichia coli and Staphylococcus aureus, and an opportunistic pathogen, Candida albicans, was investigated. A concentration of 1 mg/1 was needed to inhibit the growth of S. aureus and E. coli, while 100 mg/liter was sufficient for the growth inhibition of Candida albicans. The ion leakage of potassium and phosphate from E. coli cell and the penetration of ethidium bromide dye into it indicate that CAFC might be able to increase the cell permeability and consequently cellular leakage, thus leading to cell plasmolysis. Scanning electronmicroscope showed that E. coli cells treated with CAFC became irregular, swelling and expanded. In a field trial, control piglets showed average mortality of up to 60% within 3 days after the onset of diarrhea. In contrast, CAFC-treated groups without mortality was decreased to average 56% on the 1 st day after the treatment, and average 7% on the 3rd day. After then, piglets with diarrhea was not found.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.9
• /
• pp.1322-1326
• /
• 2013

New antifungal agents are required to compensate for the increase in resistance to standard antifungal agents of Candida albicans, which is an important opportunistic fungal pathogen that causes minor infections in many individuals but very serious infections in those who are immune-compromised. In this study, combinations of theaflavin and epicatechin are investigated as potential antifungal agents and also to establish whether antifungal synergy exists between these two readily accessible and cost-effective polyphenols isolated from black and green tea. The results of disc diffusion assays showed stronger antibacterial activity of theaflavin:epicatechin combinations against C. albicans NCTC 3255 and NCTC 3179, than that of theaflavin alone. Minimum inhibitory concentrations (MICs) of 1,024 ${\mu}g/ml$ with theaflavin and 128-256 ${\mu}g/ml$ with theaflavin:epicatechin combinations were found. The fractional inhibitory concentration indexes were calculated, and the synergy between theaflavin and epicatechin against both isolates of C. albicans was confirmed. Theaflavin:epicatechin combinations show real potential for future use as a treatment for infections caused by C. albicans.

• Tuberculosis and Respiratory Diseases
• /
• v.74 no.5
• /
• pp.215-221
• /
• 2013

Background: Nontuberculous mycobacteria (NTM) are considered opportunistic pathogens, and several species of NTM are associated with human diseases that typically involve the pulmonary, skin/soft tissue, or lymphatic systems; such infection may also cause disseminated diseases. Recent studies have reported increasing rates of NTM-induced disease worldwide. Methods: Respiratory samples are being analyzed for acid-fast bacilli (AFB) culture and NTM identification at Dankook University Hospital in Cheonan, Korea, from September 2005 to September 2011. Identification is performed by using polymerase chain reaction-restriction fragment length polymorphism analysis targeting a novel region of the rpoB gene. Results: A total of 25,133 specimens were received for AFB culture, of which 1,014 (4.0%) were NTM-positive. A total of 267 samples from 186 patients were tested for NTM identifications, and 232 samples from 157 patients were positive for NTM species. Among the patients who tested positive for NTM, 65.6% were men and the average age was 63.3 years. Mycobacterium avium complex, the most commonly detected NTM pathogen, was found in 65.9% of the 232 samples. The annual average percentage of NTM isolates from AFB culture-positive specimens was 31.3%: the highest rate was seen in 2011 (44.3%), followed by 2009 (37.4%) and 2010 (37.2%). An upward trend in NTM incidence was found during the study period. Conclusion: The prevalence of pulmonary NTM isolates continues to increase in Cheonan, suggesting that pulmonary NTM disease is becoming increasingly common.

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.5
• /
• pp.755-761
• /
• 2006

Recently, there is growing interest in ultraviolet (UV) irradiation as a disinfection technic in drinking water production due to its effectiveness to inactivate microorganisms such as Crytosporidium parvum without forming disinfection byproducts. However, UV disinfection is known for its drawback such as photoreactivation. Despite many works concerning the photoreactivation, most of works were focused on indicator or non pathogenic microorganisms. The objective of this study is to examine the photoreactivation of Pseudomonas aeruginosa which is an opportunistic pathogen as UV radiation by LP and MP UV lamp was applied. The result showed that P. aeruginosa had high photo repair efficiency regardless of the type of UV irradiation. Both of the effective log repair values of LP and MP UV irradiation were found approximately 2.6 log. In addition, photo repaired P. aeruginosa was not significantly different in forming biofilm in comparison with non treated P. aeruginosa.

• Korean Journal of Veterinary Service
• /
• v.39 no.3
• /
• pp.175-181
• /
• 2016

Staphylococcus pseudintermedius is an important opportunistic pathogen of dog and cats. Since 2006 there has been a significant emergence of methicillin-resistant S. pseudintermedius (MRSP) mainly due to clonal spread. The aim of this study was to investigated the prevalence of antibiotic resistance and presence of mecA and femA gene in 91 S. pseudintermedius isolates isolated from dogs and cats associated with various clinic infections. Methicillin resistance was confirmed by oxacillin disc diffusion method. MRSP isolate was detected 19 isolates (20.9%). MRSP and methicillin-resistant S. pseudintermedius (MSSP) isolates were highly resistant to penicillin, kanamycin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, clindamycin, ciprofloxacin, enrofloxacin and choloramphenicol (100~47.3% and 90.3~33.3%, respectively). About 90% of MRSP isolates were multi-drug resistance (resistance to at least five or more antimicrobials), and MSSP isolates was ca 74%. Among the 91 isolates, mecA gene was detected in 25 isolates (27.5%, 19 in MRSP isolates and 6 in MSSP isolates), but none carried the femA gene. Our results indicated MRSA isolates show a strong resistance to antimicrobials commonly used in veterinary medicine. A continuous surveillance and monitoring should be called for to prevent the contamination and spread of MRSP in dogs and cats.

• Journal of Korean Society on Water Environment
• /
• v.28 no.6
• /
• pp.911-916
• /
• 2012

Recently, antibiotic resistant genes (ARGs) in the environment are emerging as pollutants, since these genetic contaminants can eventually be transferred to human pathogens. The aim of this study was to develop the experimental model of antibiotic resistant gene (ARG) plasmid transfer as a function of various environmental conditions. For this purpose, the multi drug resistant plasmid pB10, which is known to be originally isolated from a wastewater treatment plant, was selected as a model transfer plasmid and Escherichia coli $DH5{\alpha}$ containing pB10 was used as a model donor. Pseudomonas aeruginosa, an opportunistic pathogen, was selected as the recipient for the conjugation experiment. When the donor and recipient were exposed to various stressors including antibiotics and heavy metal as a function of the concentrations (10, 100 and, 1000 ppb), statistically increased plasmid transfer rate was observed at a concentration of 10 ppb of tetracycline and sulfamethoxazole compared to control (no antibiotic exposure). Accordingly, the developed experimental ARG model by various stressor is a promising tool for evaluating the dissemination of ARGs by micro-contaminants in aquatic environment.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.7
• /
• pp.1227-1234
• /
• 2008

Pseudomonas aeruginosa is an opportunistic human pathogen that produces and secretes exopolysaccharides (EPS), in which cells are embedded to form a highly organized community structure called biofilm. Here, we characterized the role of cyclic diguanylate (c-di-GMP) and EPS (PEL) overproduction in the wspF mutant phenotypes of P. aeruginosa PA14 (wrinkly appearance, hyperadherence, impaired motilities, and reduced virulence in acute infections). We confirmed that the elevated c-di-GMP level plays a key role in all the wspF mutant phenotypes listed above, as assessed by ectopic expression of a c-di-GMP-degrading phophodiesterase (PvrR) in the wspF mutant. In contrast, PEL EPS, which is overproduced in the wspF mutant, was necessary for wrinkly appearance and hyperadherence, but not for the impaired flagellar motilities and the attenuated virulence of the wspF mutant. These results suggest that c-di-GMP affects flagellar motility and virulence, independently of EPS production and surface adherence of this bacterium.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.26 no.1
• /
• pp.74-80
• /
• 2012

Candida albicans is a common opportunistic pathogen and is frequently associated with biofilm formation occurring on the surfaces of host tissues and medical devices. On account of the distinct resistance of C. albicans biofilms to the conventional antifungal agents, new strategies are required to cope with these infections. The root of Polygonum cuspidatum has been used for medicinal purposes in East Asia. The aim of this study was to assess the anticandidal potential of the P. cuspidatum ethanol extract by evaluating biofilm formation, integrity of the cell membranes of C. albicans and adhesion of C. albicans cells to polystyrene surfaces. The growth and development of the biofilm was assessed using an XTT reduction assay, and the extract (0.39 mg/ml) significantly reduced ($41.1{\pm}17.8%$) biofilm formation of 11 C. albicans strains. The extract damaged the cell membranes of C. albicans and remarkably inhibited cell adhesion to polystyrene surfaces. The plant extract displayed fungistatic activity without significant hemolytic activity. Based on the results of this study, the P. cuspidatum extract has promising potential for use in treating biofilm-associated Candida infection.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.4
• /
• pp.579-585
• /
• 2013

Streptococcus equi ssp. zooepidemicus (Streptococcus zooepidemicus, SEZ) is an important pathogen associated with opportunistic infections of a wide range of species, including pigs and humans. The absence of a suitable vaccine makes it difficult to control SEZ infection. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has been previously identified as an immunogenic protein using immunoproteomic techniques. In the present study, we confirmed that the sequence of GAPDH was highly conserved with other Streptococcus spp. The purified recombinant GAPDH could elicit a significant humoral antibody response in mice and confer significant protection against challenge with a lethal dose of SEZ. GAPDH could adhere to the Hep-2 cells, confirmed by flow cytometry, and inhibit adherence of SEZ to Hep-2 cells in an adherence inhibition assay. In addition, real-time PCR demonstrated that GAPDH was induced in vivo following infection of mice with SEZ. These suggest that GAPDH could play an important role in the pathogenesis of SEZ infection and could be a target for vaccination against SEZ.