• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.694-699
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• 2000

Serratia marcescens IRBG500 and Herbaspirillum seropedicae Z67 grow endophytically in rice. The ability of these bacteria to colonize rice grown under increased nutrient availability was assessed in variety IR72 using strains marked with transposon-based gusA. The endophytic colonization was monitored via bacterial enumeration and histochemical visualization of GUS expression of bacteria in plant tissues. Rhizoplane and endophytic colonization by both bacteria was significantly inhibited in the rice plants grown in the presence of 10 mM $NH_4Cl$. In contrast, the addition of 10 mM $KNO_3$ showed no adverse effect on colonization. Increasing the concentration of $Ca^{2+}$ to 5 mM significantly reduced endophytic colonization by both bacterial strains, whereas the addition of 0.5 mM $Fe^{2+}$ substantially lowered the colonization of roots by S. marcescens IRBG500 but showed no effect on colonization by H. seropedicae Z67. Taken together, these finding suggest that, like in legume-rhizobial symbiosis as well as plant-pathogen interactions, nutrient status, particularly $NH_4^+$ and $Ca^{2+}$ concentrations in the surrounding medium, plays an important role in the regulation of endophytic infection and colonization processes in rice.

• Journal of Korean Academy of Nursing
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• v.43 no.2
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• pp.287-295
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• 2013

Purpose: The purpose of this study was to identify vancomycin-resistant enterococcus (VRE) colonization rate in patients admitted to the intensive care unit (ICU), associated risk factors and clinical outcomes for VRE colonization. Methods: Of the 7,703 patients admitted to the ICUs between January, 2008 and December, 2010, medical records of 554 VRE colonized and 503 uncolonized patients were reviewed retrospectively. To analyzed the impact of colonization on patients' clinical outcomes, 199 VRE colonized patients were matched with 199 uncolonized patients using a propensity score matching method. Results: During the study period, 567 (7.2%) of the 7,703 patients were colonized with VRE. Multivariate analysis identified the following independent risk factors for VRE colonization: use of antibiotics (odds ratio [OR]=3.33), having bedsores (OR=2.92), having invasive devices (OR=2.29), methicillin-resistant Staphylococcus aureus co-colonization (OR=1.84), and previous hospitalization (OR=1.74). VRE colonized patients were more likely to have infectious diseases than uncolonized patients. VRE colonization was associated with prolonged hospitalization and higher mortality. Conclusion: Strict infection control program including preemptive isolation for high-risk group may be helpful. Further research needs to be done to investigate the effects of active surveillance program on the incidence of colonization or infection with VRE in the ICU.

• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.539-547
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• 2009

This study was conducted to investigate the arbuscular mycorrhizal fungal biodiversity, spore density and root colonization in relation to site ages at expressway cut-slopes in Korea. Stabilization of exposed surface involved soil amendments and spraying seed mixture of turf grasses and/or nitrogen-fixing shrub species. Eighteen sites were selected with varying ages (2 to 16 years). Soil samples collected in October from each site were analyzed for fungal diversity and spore counts. Fine root samples from the plants were assayed for fungal colonization. Of the total 37 plants inspected in the sites, 26 species had endomycorrhizal colonization with an average root colonization rate of 18%, and with a range from 1 to 67%. The average endomycorrhizal colonization rate of initially introduced Festuca arundinacea which became the most dominant grass in later stage showed 22.8%, while that of Lespedeza bicolor which became the most dominant woody species were 21.6%. Naturally-invading Robinia pseudoacacia showed higher colonization rate in the old sites. Although site age did not show significant effects on fungal diversity, the root colonization rates of initially introduced plants decreased with the site aging, while those of invading plants increased with aging of the sites. The soil chemical properties, pH, N, and P contents, were negatively correlated with spore density, root colonization and endomycorrhizal species diversity. A total of forty arbuscular mycorrhizal fungal species in seven genera were identified. Of the 40 species, Acaulospora lacunosa, Glomus aggregatum, Glomus constrictum, Scutellospora erythropa, and Acaulospora spinosa were the five most dominant species in the decreasing order.

• The Journal of Internal Korean Medicine
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• v.40 no.5
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• pp.974-982
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• 2019

Objective: Modern medicine offers no efficient way to clear colonization by vancomycin-resistant enterococci (VRE). However, VRE decolonization needs to be cleared as soon as possible to prevent VRE transmission. This study reports six cases in which the duration of vancomycin resistant enterococcus (VRE) colonization was reduced by Bojungikki-tang-gami. Methods: Six inpatients with VRE colonization were administered Bojungikki-tang-gami and continuously followed up with cultures. After three negative stool cultures, the patients were declared cleared of VRE colonization. We recorded the duration of VRE colonization. Results: The duration of VRE colonization in the six patients was a mean of 58 days and a median of 45 days. This was shorter than the duration reported in most previous studies. No side effects were noted. Conclusions: The findings of this study suggest that Bojungikki-tang-gami might be effective in shortening the duration of VRE colonization.

• Mycobiology
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• v.45 no.1
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• pp.15-19
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• 2017

This study proposed a rapid method to quantify the colonization rate of arbuscular mycorrhizal fungi (AMF) in plant roots. The method involved the use of an image analysis software (WinRHIZO Pro). The colonization rate is defined as the ratio of the fungal body to the plant root area in a micrograph. Three seedlings of Chengiopanax sciadophylloides, a woody species that accumulates radiocesium, were collected from a secondary forest in the Yamakiya district of Kawamata, Fukushima Prefecture during May-September 2014. The colonization of AMF structures was examined under a light microscope, and the percentage of colonization was determined using the WinRHIZO method. The superiority of the new method was verified by comparing with a modified grid-line intersect method. The colonization of AMF was confirmed in all the seedlings, and a significant coefficient of determination ($R^2=0.94$) was found with both the methods. The results suggested that the WinRHIZO method is reliable for estimating the colonization of AMF in C. sciadophylloides.

• Neonatal Medicine
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• v.18 no.2
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• pp.272-279
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• 2011

Purpose: The incidence of nosocomial infection caused by Gram-negative bacilli (GNB) has increased in neonatal intensive care units (NICU). This study identified the progression of sepsis caused by GNB colonization and analyzed the risk factors associated with using periodic stool culture surveillance. Methods: We included 86 newborns admitted to the NICU, Kosin University Gospel Hospital from October 2007 to May 2008. Three stool specimens were collected right after birth and two more were collected at 2 week intervals. The risk factors related to GNB colonization were established from each medical record and related references. Results: The incidence of colonization by GNB was 22 (25.6%) per 86 neonates but none had culture-proven sepsis. The three most commonly isolated GNB were Pseudomonas aeruginosa, Enterobacter cloacae, and Citrobacter freundii. Approximately 89% (32/36) of isolated GNB were susceptible to amikacin. The probability of GNB colonization increased in infants who were fed a small volume during enteral feeding. In contrast, delayed enteral feeding resulted in a decreased probability for GNB colonization. Conclusion: Colonized GNB in the intestine was confirmed by enteric surveillance culture of newborns admitted to the NICU. However, we found no evidence of culture-proven GNB sepsis. As lower feeding volume on the colonization day is a risk factor for GNB colonization, the chance for GNB colonization should be considered when feeding intolerance is present.

• Pediatric Infection and Vaccine
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• v.19 no.3
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• pp.111-120
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• 2012

Purpose: The aim of this study is to investigate the colonization rate of Methicillin-resistant Staphylococcus aureus (MRSA) in neonates by different clinical characteristics, to presume the origin of MRSA acquisition, and to identify the risk factors associated with MRSA colonization. Methods: We retrospectively reviewed the medical records of 1,733 neonates admitted to Seoul Eulji hospital Neonatal Intensive Care Unit between January 2008 and December 2011. Nasal, inguinal and rectal swab specimens were obtained upon admission and each week until discharge. We classified the route of MRSA acquisition as; hospital associated (HA-MRSA) and community associated (CA-MRSA) according to the case definition. Results: Among 1,733 neonates, 415 (23.9%) were colonized with MRSA. Gestational age, birth weight, delivery type, maternal antibiotics usage before delivery, birth place and care place before admission were influencing factors in colonization of MRSA. The colonization rate was significantly high in neonates without maternal prophylactic antibiotics use before delivery than in the other group (relative risk 2.77, 95% CI 1.88-4.07; P<0.01), and outborns showed higher MRSA colonization rate compared to inborns (relative risk 2.28, 95% CI 1.17-4.42; P=0.015). Conclusion: We identified the neonatal MRSA colonization rate to be 23.9%. We estimated HA-MRSA colonization rate to be 10% (51/511) and CA-MRSA colonization rate to be 36% (309/858). We ascertained that risk factors in MRSA colonization in neonates were prophylactic use of antibiotics in mothers and the birth place.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.15 no.4
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• pp.522-530
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• 2008

Purpose: In this study active surveillance culture for ICU patients, in whom the risk of VRE infection was high were conducted, and through this the VRE colonization rate and the characteristics of the colonization were examined and risk factors involved in VRE colonization and acquisition were analyzed. Method: This research was performed with 635 patients admitted to ICU between July 1 and December 31, 2006. Results: On admission to ICU, the VRE colonization rate was 2.36%, 93% identified from active surveillance culture. The VRE colonization rate was significantly higher in those patients with cancer (OR=9.43; 95% CI=1.38${\sim}$62.50; P=.022), liver cirrhosis (OR=55.5; 95% CI=7.29${\sim}$500; P=.005), transferred from other hospitals (OR=200; 95% CI=22.73${\sim}$1000; P=.000), high APACHE II score (OR=1.107; 95% CI=1.010${\sim}$1.213; P=.029), or antibiotics within the last 3 months (OR=15.87; 95% CI=2.27${\sim}$111.11; P=.005). The VRE acquisition rate was 5.2%. It was significantly higher in those who were using a ventilator (OR=26.31; 95% CI=5.13${\sim}$142.86; P=.000), three or more kinds of antibiotics during admission (OR=58.82; 95% CI=16.13${\sim}$200; P=.000), or high APACHE II score (OR=1.16; 95% CI=1.08${\sim}$ 1.24; P=.000). Conclusion: The results of this study show that active surveillance culture can detect VRE colonization on admission to ICU and those who have acquired VRE in ICU. The analyzed VRE colonization and risk factors of VRE acquisition are expected to be useful in establishing guidelines for preventing VRE infection in ICU.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.20 no.1
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• pp.47-54
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• 2017

Purpose: Clinical symptoms associated with Clostridium difficile infection (CDI) can vary widely. Carrier state without apparent symptoms is relatively common during infancy. The objective of this study was to determine the association of C. difficile colonization with bowel habit change and the effect of C. difficile colonization treatment on restoration of normal bowel habit. Methods: Between 2006 and 2014, infants at 1 to 12 months of age with diarrhea for more than 2 weeks who did not improve with conservative care were recruited from Gachon University Gil Medical Center. Infants who were followed up for at least 7 days were included. The presence or absence of C. difficile colonization, effect of metronidazole, and other medical records were reviewed. To determine the association between CDI and bowel habit change, logistic regression analysis was used. Results: Of a total of 126 infants, 74 (58.7%) were male patients. Of the 126 patients, 27 (21.4%) had C. difficile colonization. Significant (p<0.05) risk factors for C. difficile colonization included artificial milk feeding (odds ratio [OR], 4.310; 95% confidence interval [CI], 1.564-11.878), prior rotavirus vaccination (OR, 4.322; 95% CI, 1.018-18.349), and antibiotic use (OR, 4.798; 95% CI, 1.430-16.101). There was improvement in bowel habit after metronidazole therapy (OR, 0.34; 95% CI, 0.15-0.79; p<0.05), regardless of the presence or absence of C. difficile colonization, Conclusion: There was no significant correlation between bowel habit change and C. difficile colonization during infancy. However, metronidazole can be used as an optional method to manage functional gastrointestinal disorders.

• Applied Microscopy
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• v.34 no.2
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• pp.103-111
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• 2004

Fresh specimens of the aquatic macrophyte, Spirodela polyrhiza, have been examined employing scanning and transmission electron microscopy. Observations revealed the occurrence of microbial colonization during development. Submerged parts of the small, free-floating S. polyrhiza body exhibited a variety of microorganisms such as bacteria, cyanobacteria, and diatoms throughout their development. However, immature and/or young plants normally demonstrated much less microbial colonization compared to mature plants. During the study, heavy colonization by the microorganisms was routinely encountered at maturity, especially in the fully developed abaxial fronds and root caps. The mucilaginous layer was shown along the root caps, and the microorganisms appeared to be either clustered or attached to this layer. In contrast, only moderate degrees of colonization were observed in the root, and little to no colonization was observable in the adaxial frond surface. Transmission electron microscopy clearly demonstrated the microbial colonization to be external in the S. polyrhiza specimen examined in the current study. The association between the microorganisms and S. polyrhiza has been considered non-harmful, as no frond senescence and almost no mechanical penetration of the plant by the microorganisms were noticed during the study.