• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.5
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• pp.606-611
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• 2009

Performance test was carried out between selective media which are generally used in Staphylococcus aureus isolation from food. Sensitivity, determined according to the appearance of characteristic colonies when 30 different S. aureus strains were tested, resulted as Baird-Parker agar (RPF)> $Petrifilm^{TM}$ Staph Express plate> Baird-Parker agar> Mannitol salt agar. Also, the four different media showed the same selectivity because all tested media did not produce the false positive colonies. Recovery efficiency from the artificially inoculated foodstuff was almost the same for the tested media. Presumptive colonies were collected from the dried fishery product using Mannitol salt agar and collected strains were tested on 4 different selective agar. Almost presumptive strains did not show the false positive colonies except for S. carnosus ssp carnosus. This strain was identified as false positive colonies on Mannitol salt agar, Baird-Parker agar and $Petrifilm^{TM}$ Staph Express plate. But Baird-Parker agar (RPF) did not show the false positive colonies with the same strains. So, it was concluded that the Baird-Parker agar (RPF) has more higher selectivity than other tested media in this experiment.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.133-139
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• 2011

In this study, we determined the changes in microbial numbers in solar salts according to the manufacturing process and storage duration. The salt samples were harvested from salt farms in Shinan (area 2) and Yeonggwang (area 1). They were serially diluted ten-fold and then placed on 4 kinds of cultivable media (mannitol salt agar, eosin methylene blue, plate count agar, and trypticase soy agar). After incubation, we obtained 62 halophilic isolates from the salt samples. Coliform and general bacteria were not detected in all salt samples. By 16S rRNA sequencing analysis, we found 12 kinds of halophilic bacteria belonging to the genera Halobacillus, Halomonas, Bacillus, Idiomarina, Marinobacter, Pseudoalteromonas, Vibrio, Salinivibrio, Virgibacillus, Alteromonas, Staphylococcus and some un-known stains. In our study, we discovered two novel species that have a 16S rDNA sequence similarity below 97%.

• Journal of Oral Medicine and Pain
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• v.18 no.1
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• pp.73-82
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• 1993

To investigate the changes in aerobic and facultative anaerobic oral microflora during remission-induction chemotherapy in patients with acute myeloid leukemia, 10 consecutive patients were studied during a period of 28 days. One day before, during and after the induction therapy, patients were given 10% Betadine solution for mouthrinses after breakfast and kept from eating and drinking. After 3 hours, paraffin-stimulated whole saliva was obtained for 2 minutes and transported to the laboratory. The samples were dispersed and homogenized by use of vortex mixer for 20 seconds. From these samples 10-fold serial dilutions (from 10-1 through 10-3) were prepared. Each dilution of 0.1 ml was plated on duplicate set of one nonselective medium (Blood agar) and four selective media (Sabourauds dextrose agar, Mannitol salt agar, Mac-Conkey agar, SF medium ) using applicator woods. All agar plate were incubated at 37$^{\circ}C$ for 48 hours. The total number of microorganisms was calculated and the percentage distribution of the various microorganisms from each specimen was drawn. 1. The salivary flow rate decreased by 66%, going from 5.38 ml/2min to 1.81 ml/2min over two days during the chemotherapy. 2. The total number of microorganisms in saliva increased by 22%, going from 4.88$\times$105/ml to 6.00$\times$105/ml over two days during the chemotherapy. 3. The salivary flow rate and the total number of microorganisms in saliva were recovered within 28 days after the chemotherapy. 4. The quantitative alteration in oral Enterobacteria, Enterococci, Staphylococci, Cndida during the chemotherapy had no statistical significance. 5. In saliva of the patients with acute myeloid leukemia who ahd intraoral ulcer, Enterobacteria was quantitatively predominent. Our study suggests that chemotherapy-induced transient xerostomia may induce acute oral infection. Consequently, the use of saliva substitute, the removal of intraoral infection source and the consistent oral hygiene care seem to be required to avoid the transmission of potential pathogenes in this group of patients.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.340-346
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• 1996

In order to find out if staphylococci occur in significant numbers in Korean fermented fish products, a total of 40 different fermented fish products were collected from different markets in Korea and analyzed for their physico-chemical and microbiological states. The pH, salt concentration and water activity of the products were measured and the total viable cell count and the number of Staphylococcus grown on mannitol salt agar were determined. The identification of the strains of Staphylococcus were made by API Staph Strip and MIS identification kits, and the physiological properties of the identified strains were further characterized by different conventional methods. The pH, salt content and water activity of fermented fish samples varied widely from 4.8 to 7.1, 7.4-28.7$%$ and 0.77-0.84, repectively, depending on the type of product. The total viable cell count varied from $10^4-10^9$ cfu/ml, and most of the samples had $10^5-10^6$ cfu/ml No correlation was found between the viable cell count and the pH, NaCl concentration and water activity of the samples. Among the 35 colonies identified as Staphylococcus strains by the identification kits, S. xylosus was the most frequently occurring strain marking 17, and S. warneri was 8, S. epidermidis 4 and S. cohnii 2. S. hominis, S. saprophyticus, S. haemolyticus and S. aureus were also identified once each. In some samples (K-3, P-6, K-8, G-5 and G-10), 2-3 different species of Staphylococcus were found. Considering the region of sampling, among the 10 samples from Kunsan 5 were identified as S. warneri, while in the other regions S. xylosus was predominant. Although the physiological characteristics of the identified strains were generally consistent with those in Bergey's Manual, some discrepances were also observed. All the strains were highly salt tolerant, growing in the media containing over 18$%$ NaCl. All the strains except S. aureus (G-11) showed negative in hemolysis activity, plasma coagulation and DNase tests. All the strains including S. aureus (G-11) showed negative in enterotoxin test.

• Journal of Food Hygiene and Safety
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• v.27 no.2
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• pp.169-175
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• 2012

Five kinds of selective media, such as mannitol salt agar (MSA), Baird-Parker agar (BPA), Baird-Parker supplemented with rabbit plasma fibrinogen (BPA+RPF), CHROMagar Staphylococcus aureus (CSA), and Petrifilm Staph Express count system (Petrifilm), were compared to recommend the optimum selective media for isolation of Staphylococcus aureus from agricultural products. Seventy four target and non target bacteria were inoculated on five selective media to analyze sensitivity and specificity. In the recovery test of injured S. aureus cells, S. aureus was exposed to acid (1% lactic acid for 10 min), heat ($60^{\circ}C$ for 90s), and cold ($-20^{\circ}C$ for 1h) conditions. And artificially contaminated agricultural products (iceberg lettuce, green pepper, and cherry tomato) was enumerated on five selective media. The sensitivity of BPA+RPF, CSA, Petrifilm, MSA, and BPA were 100%, 100%, 100%, 90.5%, 90.5%, respectively. In addition, the specificity of BPA+RPF, CSA, MSA, BPA and Petrifilm were 100%, 100%, 84.6%, 75.0%, 67.3%, respectively. However, no difference among five selective media was observed in recovery on injured S. aureus cell and enumeration from agricultural products. This results suggest that BPA+RPF and CSA are the optimum media for detection of S. aureus from agricultural products.

• Korean Journal of Clinical Laboratory Science
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• v.44 no.3
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• pp.118-123
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• 2012

Nosocomial infection and community-acquired infection with Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), has become a strong concern in human body sites and related effects. The aim of this study is investigate the isolation rate of MRSA from nasal cavity inferior regions and cellular phones to assess the risk factor of nosocomial infection and community-acquired infection. 34.7% and 37.2% isolates were MRSA from the nasal cavity inferior regions and cellular phones according to a Mannitol salt agar (added oxacillin $6{\mu}g/mL$) culture and PCR according to S. aureus specific 16S rRNA and mecA primers. Thus, the distribution of S. aureus and the isolation rate of MRSA represent a very high risk factor regards nosocomial infection and community-acquired infection.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.217-221
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• 2013

This study developed predictive models for the kinetic behavior of Staphylococcus aureus on processed cheeses. Mozzarella slice cheese and cheddar slice cheese were inoculated with 0.1 ml of a S. aureus strain mixture (ATCC13565, ATCC14458, ATCC23235, ATCC27664, and NCCP10826). The inoculated samples were then stored at $4^{\circ}C$ (1440 h), $15^{\circ}C$ (288 h), $25^{\circ}C$ (72 h), and $30^{\circ}C$ (48 h), and the growth of all bacteria and of S. aureus were enumerated on tryptic soy agar and mannitol salt agar, respectively. The Baranyi model was fitted to the growth data of S. aureus to calculate growth rate (${\mu}_{max}$; ${\log}CFU{\cdot}g^{-1}{\cdot}h^{-1}$), lag phase duration (LPD; h), lower asymptote (log CFU/g), and upper asymptote (log CFU/g). The growth parameters were further analyzed using the square root model as a function of temperature. The model performance was validated with observed data, and the root mean square error (RMSE) was calculated. At $4^{\circ}C$, S. aureus cell growth was not observed on either processed cheese, but S. aureus growth on the mozzarella and cheddar cheeses was observed at $15^{\circ}C$, $25^{\circ}C$, and $30^{\circ}C$. The ${\mu}_{max}$ values increased, but LPD values decreased as storage temperature increased. In addition, the developed models showed acceptable performance (RMSE = 0.3500-0.5344). This result indicates that the developed kinetic model should be useful in describing the growth pattern of S. aureus in processed cheeses.

• Journal of Korean Biological Nursing Science
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• v.5 no.2
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• pp.21-30
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• 2003

The effect of hand hygiene was measured by hand culture before and after hand hygiene for 86 nurses, doctors, and nurses aide/housekeepers in Surgical Intensive Care Unit. The subjects were asked to press their dominant hand in hand-shaped Mannitol salt agar immediately after patient contact and then washed their hand by preferred hand hygiene agents [soap and water, waterless alcohol gel, or 4% chlorhexidine gluconate detergent (CHG)], and cultured one hand again Amount of isolated microorganism was calculated by counting the number of divided areas ($1{\times}1cm$) which is culture positive in hand culture plate. The amount of microorganisms were significantly reduced from 58.1(${\pm}38.59$) to 27.4(${\pm}30.4$) cells after hand hygiene. The staff nurse's hand hygiene was more effective compared to medical doctors and nurses aide/housekeepers. Methicillin-resistant Staphylococcus aureus(MRSA) was isolated in 41(47.1%) subjects ; but only removed 100% in 28(32.2%) subjects. When the amount of hand microorganisms was compared by subject's preferred hand hygiene agents, it was decreased in order of 4% CHG, waterless alcohol solution, soap and water, and water. The hand hygiene practice was inadequate to reduce hand microorganisms and significantly different by occupations. Further research and development of hand hygiene improvement program which emphasize the quality of hand hygiene is recommended.

• Journal of Microbiology and Biotechnology
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• v.32 no.12
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• pp.1537-1546
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• 2022

Staphylococcus aureus is a cause of high mortality in humans and therefore it is necessary to prevent its transmission and reduce infections. Our goals in this research were to investigate the frequency of methicillin-resistant S. aureus (MRSA) in Taif, Saudi Arabia, and assess the relationship between the phenotypic antimicrobial sensitivity patterns and the genes responsible for resistance. In addition, we examined the antimicrobial efficiency and application of silver nanoparticles (AgNPs) against MRSA isolates. Seventy-two nasal swabs were taken from patients; MRSA was cultivated on Mannitol Salt Agar supplemented with methicillin, and 16S rRNA sequencing was conducted in addition to morphological and biochemical identification. Specific resistance genes such as ermAC, aacA-aphD, tetKM, vatABC and mecA were PCR-amplified and resistance plasmids were also investigated. The MRSA incidence was ~49 % among the 72 S. aureus isolates and all MRSA strains were resistant to oxacillin, penicillin, and cefoxitin. However, vancomycin, linezolid, teicoplanin, mupirocin, and rifampicin were effective against 100% of MRSA strains. About 61% of MRSA strains exhibited multidrug resistance and were resistant to 3-12 antimicrobial medications (MDR). Methicillin resistance gene mecA was presented in all MDR-MRSA strains. Most MDR-MRSA contained a plasmid of > 10 kb. To overcome bacterial resistance, AgNPs were applied and displayed high antimicrobial activity and synergistic effect with penicillin. Our findings may help establish programs to control bacterial spread in communities as AgNPs appeared to exert a synergistic effect with penicillin to control bacterial resistance.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.241-246
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• 2013

The objective of this study was to evaluate microbial growth patterns on Korean foods containing collagen. Samgyetang, Ugultang, Odolbyeboguem, Jeonyak, and Jokbal were inoculated with Staphylococcus aureus and Salmonella spp., and incubated at $4^{\circ}C$ (6 days), $10^{\circ}C$ (6 days), $20^{\circ}C$ (3 days), and $30^{\circ}C$ (36 h). Cell counts of S. aureus and Salmonella spp. were enumerated on mannitol salt agar and xylose lysine deoxycholate agar, respectively. Of the 5 foods, S. aureus and Salmonella cell counts decreased (P < 0.05) only in Jeonyak. To understand this reduction in cell growth on Jeonyak, extracts of ingredients such as clove, cinnamon, pepper, ginger, and jujube were examined to determine minimal bactericidal concentrations (MBC; AU/mL). Clove (3.13 AU/mL), cinnamon (50 AU/mL), pepper (25 AU/mL), and ginger (50 AU/mL) extracts displayed antimicrobial activity against S. aureus, and clove and cinnamon extracts displayed antimicrobial activity against Salmonella. The results indicate that Jeonyak has antimicrobial activity against S. aureus and Salmonella, and clove and cinnamon are the primary antimicrobial agents in this food.