• Annals of Clinical Microbiology
• /
• v.22 no.1
• /
• pp.9-13
• /
• 2019

Background: The isolation of carbapenemase-producing Enterobacteriaceae (CPE) has become increasingly common. Continuous surveillance for these organisms is essential because their infections are closely related to outbreaks of illness and are associated with high mortality rates. The aim of this study was to develop and evaluate multiplex PCR as a means of detecting several important CPE genes simultaneously. Methods: We aimed to develop a multiplex PCR that could detect seven CPE genes simultaneously. The multiplex PCR was composed of seven primer sets for the detection of KPC, IMP, VIM, NDM-1, GES, OXA-23, and OXA-48. We designed different PCR product sizes of at least 100 bp. We evaluated the performance of this new test using 69 CPE-positive clinical isolates. Also, we confirmed the specificity to rule out false-positive reactions by using 71 carbapenem-susceptible clinical strains. Results: A total of 69 CPE clinical isolates showed positive results and were correctly identified as KPC (N=14), IMP (N=13), OXA-23 (N=12), OXA-48 (N=11), VIM (N=9), GES (N=5), and NDM (N=5) by the multiplex PCR. All 71 carbapenem-susceptible clinical isolates, including Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, showed negative results. Conclusion: This multiplex PCR can detect seven CPE genes at a time and will be useful in clinical laboratories.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.5
• /
• pp.398-404
• /
• 1984

This study was attempted to investigate variation of the bacterial flora in waste water treatment of fish meat paste plant by batch and continuous culture. The results of the experiment are as follows : 1. The removal rate of BOD in waste water treatment by activated sludge of continuous culture was above $90\%$. 2. In the process of nitric acidification of protein waste water, $NH_4-N\;and\;NO_2-N$ increased untill the lapse of 48 hours from culture, but $NO_3-N$ showed little change. 3. In activated sludge obtained from acclimation by batch culture for 10 days, bacteria good in capacity of nitric acidification were not appeared. 4. Among 120 strains of isolated bacteria, the most predominantly appeared bacterial flora were Enterobacteriaceae ($28\%$) and Pseudomonas spp. ($25\%$), In the latter term of aeration during which ammonia originates in abundance, Pseudomonas spp. was decreased but Enterobarteriaceae was increased. 5. Fifty percent of the isolated strains were able to grow in $0\%,\;3\%$ NaCl and $75\%$ artificial sea water, Therefore, it is suggested that sea water can be used as dilution water instead of tap water during the treatment of waste water.

• Korean Journal of Microbiology
• /
• v.47 no.4
• /
• pp.335-341
• /
• 2011

In this study, 22 clinical isolates of Enterobacteriaceae including Citrobacterfreundii (6 strains), Enterobacter cloacae (5 strains), Enterobacter aerogenes (3 strains), Serratia marcescens (7 strains) and Pantoea spp. (1 strain) were investigated for the biofilm forming ability and biosynthesis of curli and cellulose. Biofilm forming ability was the highest among the isolates of E. cloacae and the lowest among the isolates of E. aerogenes. The expression of the biofilm-forming extracellular matrix components, cellulose and curli fimbriae, was examined by Congo-red (CR) staining and calcofluor staining methods. PCR screening for the presence of curli gene (csgA) revealed that 4 strains of E. cloacae and 1 strain of C. freundii carried the csgA, showing a good correlation between the phenotypic detection of curli fimbriae by CR staining method and the genotypic detection of curli gene by PCR in E. cloacae.

• Korean Journal of Clinical Laboratory Science
• /
• v.51 no.4
• /
• pp.428-435
• /
• 2019

The rapid increase and dissemination of carbapene mases, such as Klebsiella pneumoniae carbapenemase (KPC), has become a major problem within the field of healthcare-related infection. There are few antibiotics to treat carbapenem-resistant Enterobacteriaceae (CRE) infections, so the identification of resistant bacterial mechanisms is critical to initiate infection control and conduct epidemiological research. A rapid and effective method for detecting KPC-producing bacteria is needed to avoid therapeutic failures and introduce measures to prevent and control the dissemination of these multi-resistant bacteria. During the study period, 31 isolates (seven isolates of Acinetobacter spp., six isolates of Morganella morganii, five isolates of Pseudomonas aeruginosa, five isolates of Proteus mirabilis, one isolate of Proteus vulgaris, two isolates of Enterobacter cloacae, one isolate of Enterobacter aerogenes, one isolate of Klebsiella pneumoniae, one isolate of Klebsiella oxytoca, one isolate of Serratia marcescens and one isolate of Escherichia coli) were identified by the VITEK. Gram negative rod bacteria were the most frequently isolated from urine (35.5%), blood (19.4%), sputum (16.1%), pus (9.7%), ascitic fluid (9.7%), tracheal aspirates (6.5%) and bile juice (3.2%). Analysis using the PCR method identified the bla_KPC gene in the K. oxytoca1 strain, but the bla_IMP, bla_VIM and bla_OXA-48 genes are not amplified. In conclusion, diagnosis using the PCR method can accurately and quickly diagnose KPC, thus establishing quick preventive measures to prevent the spread of KPC in hospitals.

• Korean Journal of Healthcare-Associated Infection Control and Prevention
• /
• v.21 no.2
• /
• pp.50-56
• /
• 2016

Background: Alternatives to carbapenem are increasingly needed to decrease the usage of carbapenem. We evaluated the possibility of using non-carbapenem antibiotics against urinary tract infections (UTI) caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). Methods: This retrospective study was performed at 2 university hospitals between October 2010 and December 2012. All diagnosed adult cases of ESBL-PE UTI were identified from the microbiological database. The subjects were divided into 3 groups based on the empirical antibiotic classes and susceptibility: carbapenem (C) group, susceptible non-carbapenem (SNC) group, and non-susceptible non-carbapenem (NSNC) group. Results: A total of 84 patients were eligible for analysis. For empirical therapy, 41, 23, and 20 patients were included in the NSNC, SNC, and C empirical groups, respectively. During the empirical therapy, 7 patients (17.1%) in the NSNC group, 18 patients (78.3%) in the SNC group, and 19 patients (78.3%) in the C group experienced clinical improvement. No significant difference was observed between the SNC and C empirical groups (P=0.192). Severe sepsis or shock was the predictor of empirical SNC treatment failure (P=0.048). There was a tendency to use carbapenem as a definite therapy in cases of NSNC. In contrast, empirical SNC was maintained as a definite therapy. Conclusion: SNC could be considered as an alternative to carbapenems for treating ESBL-PE UTI. This strategy might decrease the usage of carbapenem without clinical deterioration. However, it should be noted that SNC therapy may fail in the case of severe sepsis or shock.

• Animal Bioscience
• /
• v.37 no.1
• /
• pp.151-160
• /
• 2024

Objective: The growing consumers' interest on animal welfare has raised the request of products obtained by alternative rearing systems. The present study was conducted to assess the influence of housing system on gut and muscle morphology and on microbial load in rabbits reared under free-range (FR) and cage system (CS). Methods: A total of forty weaned (35 days of age) male Italian White breed rabbits were allotted according to the rearing system, and at 91 days of age were randomly selected and slaughtered for the morphological evaluation of tissue from duodenum and longissimus lumborum. Morphometric analysis of the villus height, villus width, crypt depth, villus height/crypt depth ratio, and villus surface was performed. The microbial loads on hind muscle was determined by total mesophilic aerobic count (TMAC), Escherichia coli and Enterobacteriaceae; whereas, total anaerobic bacteria count (TABC) and TMAC, E. coli and Enterobacteriaceae was determined on caecal content. Results: Rearing system did not interfere with the duodenum and muscle histomorphology in both rabbit groups. Similarly, microbial load of caecal content showed no significant differences on the TABC and TMAC. Conversely, significant difference was found for E. coli strains in caecal content, with the lower counts in FR compared to CS rabbits (p<0.01). Microbiological assay of muscle revealed significant lower TMAC in FR vs CS rabbits (p< 0.05). All rabbit meat samples were negative for E. Coli and Enterobacteriaceae. Conclusion: Free-range could be considered a possible alternative and sustainable rearing system in rabbits to preserve gut environment and muscle quality.

• Biomedical Science Letters
• /
• v.18 no.3
• /
• pp.299-306
• /
• 2012

Recently, the prevalence of 16S rRNA methylase conferring high-level resistance to aminoglycosides has been increasing in Gram-negative bacilli globally. We determined the prevalence and genotype of these methylase-producing bacteria, and characterized the co-resistance to ${\beta}$-lactam antibiotics and quinolone in Gram-negative clinical isolates collected in 2010 at a hospital in Korea. Among 65 amikacin-resistant isolates screened from 864 Gram-negative bacilli (GNB), 16S rRNA methylase genes were detected from 49 isolates, including Acinetobacter baumannii (43), Klebsiella pneumoniae (2), Proteus mirabilis (2) and Serratia marcescens (1), Empedobacter brevis (1). All of the 16S rRNA methylase genotype was armA and no variant sequences of amplified PCR products for armA were noted. The 16S rRNA methylase producing bacteria showed much higher resistance to aminoglycoside for Enterobacteriaceae and glucose non-fermenting (NF)-GNB and to imipenem for glucose NF-GNB, than the non-producing isolates. All of the 16S rRNA methylase producing Enterobacteriaceae had the extended-spectrum-${\beta}$-lactamase. In addition, two K. pneumoniae concurrently produced both plasmid-mediated AmpC ${\beta}$-lactamase and qnrB gene. All of the amikacin-resistant A. baumannii (43) co-harbored armA 16S rRNA methylase and $bla_{OXA-23}$ carbapenemase. In conclusion, 16S rRNA methylase producing bacteria were very prevalent among GNB in South Korea, and were commonly associated with co-resistance, including carbapenem and quinolone.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.11
• /
• pp.1623-1629
• /
• 2014

Dry-cured pork neck samples were stored at $10^{\circ}C$ for 90 days under vacuum packaging (VP) or modified atmosphere packaging (MAP; 25% $CO_2$+75% $N_2$) conditions. The pH, moisture, water activity, total aerobic bacteria, and Enterobacteriaceae counts of dry-cured pork neck products with MAP were significantly lower than those with VP (p<0.05) after 90 days of storage. However, CIE $b^*$ and 2-thiobarbituric acid reacted substance (TBARS) values of the pork product with MAP were significantly higher (p<0.05) than those with VP. Total aerobic bacterial counts and Enterobacteriaceae counts of samples with MAP were lower than those with VP after 30 days of storage. Sensory results indicated that aroma, flavor and tenderness scores of the samples with both VP and MAP decreased during storage and the scores after >60 days of storage were lower than those at Day 1. In conclusion, despite presenting higher lipid oxidation, the samples stored in packages containing 25% $CO_2$ for 90 days at $10^{\circ}C$ have lower bacterial counts than vacuum-packed samples. Therefore, further studies should be performed on the packaging of dry-cured meat at adjusted concentrations of $CO_2$.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.5
• /
• pp.764-768
• /
• 2010

Three different isolation media for Cronobacter sakazakii have been recommended by Korea Food and Drug Administration from 2007. Performance comparison test was carried out between recommended Cronobacter sakazakii isolation medium. Chromogenic Enterobacter sakazakii agar (CESA) and Enterobacter sakazakii agar (ESA) produce more distinctive colonies having characteristic colors and appearance than Violet red bile glucose agar (VRBGA). The sensitivity and specificity of 3 different isolation media was checked. All 3 tested media showed 100% sensitivity when tested with 30 different Cronobacter sakazakii. The CESA and ESA showed 100% specificity when tested with Enterobacteriaceae except Cronobacter sakazakii, However, VRBGA did not show any specificity, showing inadequate selectivity compared to applicable Cronobacter sakazakii isolation medium. Artificially inoculated Cronobacter sakazakii to milk powder was easily recovered with 3 different isolation media and they all showed almost the same recovery activity.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.2
• /
• pp.133-143
• /
• 2014

The development of the gut is controlled and modulated by different interacting mechanisms, such as genetic endowment, intrinsic biological regulatory functions, environment influences and last but no least, the diet influence. In this work, we compared the fecal microbiota of breast-fed (BF), formula-fed (FF), and mixed-fed (MF) infants from Hebei Province, China. By using high-throughput 16S rDNA sequencing analyses, we found some differences in gut microbiota in the three groups. Firmicutes and Proteobacteria were the dominant bacteria at the phylum level in the three groups, where FF infants showed a significant depletion in Bacteroidetes (p < 0.001) and Actinobacteria (p < 0.05). Enterobacteriaceae was the dominant bacteria at the family level in the three groups, but FF infants showed higher Enterobacteriaceae enrichment than BF and MF infants (p < 0.05); the abundance of the Bifidobacteriaceae was only 8.16% in the feces of BF infants, but higher than in MF and FF infants (p < 0.05). The number of genera detected (abundance >0.01%) in BF, MF, and FF infants was only 15, 16, and 13, respectively. This study could provide more accurate and scientific data for the future study of infant intestinal flora.