• Journal of Microbiology
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• v.43 no.3
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• pp.257-259
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• 2005

Although automated continuous-monitoring blood culture systems are both rapid and sensitive, false-positive and false-negative results still occur. The objective of this study, then, was to evaluate negative results occurring with BacT/Alert 3D blood culture systems. A total of 1032 samples were cultured with the BacT/Alert 3D automated blood culture system, using both aerobic (BPA) and anaerobic (BPN) media, and 128 of these samples yielded positive results. A total of 904 negative blood samples were then subcultured in $5\%$ sheep blood agar, eosin methylene blue, chocolate agar, and sabouraud-dextrose agar. Organisms growing on these subcultures were subsequently identified using both Vitek32 (bioMerieux, Durham, NC) and conventional methods. Twenty four $(2.6\%)$ of the 904 subcultures grew on the subculture media. The majority $(83.3\%)$ of these were determined to be gram-positive microorganisms. Fourteen $(58.3\%)$ were coagulase-negative staphylococci, two $(8.3\%)$ were Bacillus spp., one $(4.2\%)$ was Staphylococcus aureus, and one $(4.2\%)$ was identified as Enterococcus faecium. Streptococcus pneumoniae and Neisseria spp. were isolated together in two $(8.3\%)$ vials. Gram-negative microorganisms comprised $12.5\%$ of the subcultures, of which two $(8.3\%)$ were found to be Pseudomonas aeruginosa, and one $(4.2\%)$ was Pseudomonas fluorescens. The other isolate $(4.2\%)$ was identified as Candida albicans. We conclude that the subculture of negative results is valuable in the BacT/Alert 3D system, especially in situations in which only one set of blood cultures is taken.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.341-345
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• 2010

The prevalence and antimicrobial susceptibilities of Staphylococcal isolates from bovine milk samples were assessed. From January 2009 to October 2009, a total 287 bovine milk samples were randomly collected from 15 stock raising farms located in northern area of Kyunggi province and cultured for the presence of Staphylococci spp. A total 79 staphylococcal isolates were recovered from the milk samples. The predominant isolates were S. aureus (43.03%) and S. chromogenes (24.05%). Antimicrobial resistance patterns of 79 Staphylococcal isolates against ampicillin, chloramphenicol, ciprofloxacin, erythromycin, gentamicin, oxacillin, teicoplanin, tetracyclin, and vancomycin were tested. Staphylococcal isolates revealed the highest resistance to ampicillin (56.96%) and oxacillin (39.23%). Of 31 oxacillin resistance strains, 8 strains carry mecA gene which is responsible for methicillin resistance.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.581-586
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• 2007

Staphylococcus epidermidis is a coagulase-negative, gram-positive bacterium that normally inhabits the human skin. S. epidermidis is also known to be an opportunistic pathogen in infections of various indwelling medical devices. This report describes purification and characterization of the urease of S. epidermidis urease, which may act as a virulence factor. The urease from S. epidermidis was purified 1,127 fold by using DEAE-Sepharose, Phenyl-Sepharose, Mono-Q and Superdex HR200 column chromatography. The specific activity of the purified enzyme was 993.8 U/mg. Michaelis constant($K_m$) of the enzyme was estimated to be 8.5 mM urea by using Lineweaver-Burke double reciprocal plot. The native molecular weight of the urease was shown to be 255 kD by using Superose 6HR gel filtration chromatography and the purified enzyme contained 2.2 nickel ions per catalytic unit. The overall stoichiometry of the enzyme subunits appears to be $(\alpha\beta\gamma)_3$, which is consistent with the enzymes from other bacteria sources.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.2
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• pp.76-85
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• 2007

The total number of clinical materials collected from Dec 1, 2005 to Nov 30, 2006 in C. hospital was 63,133. Among these materials, the isolation of Staphylococcus spp. was 5,252 strains. The proportions of Staphylococcus species infection were as follows ; 46.7% in S. aureus, 39.3% in S. epidermidis, 4.7% in S. hominis, 3.8% in S. haemolyticus, 2.9% in S. capitis and 2.5% in others. Seventeen strains of Staphylococcus species were identified with an isolation range of 0.02-46.7%. The isolation ratios of Staphylococcus species were 7.8% (2,134/27,362) in female, 8.7% (3,118/35,807) in male and 8.3% (5,252/63,133) in both. The age-related frequencies of Staphylococcus species were 22.1% in the 60-69 year group, 19.3% in the 70-79 year group and 17.1% in the 50-59 year group. The isolation ratio of the 0-49 year group to the 50-over 80 year group were 1.74 times in female, 1.92 in male and 1.85 in both. The isolation frequency of Staphylococcus spp. was at its highest in April (9.9%) and at its lowest in February (6.8%) according to monthly analysis. According to seasonal variation, the isolation frequencies of Staphylococcus spp. were 27.0% in Summer, 25.9% in Spring, 23.9% in Fall and 23.2% in Winter. The clinical departments showing over 9% isolation rate against Staphylococcus spp. were critical care medicine (12.9%), department of pediatrics (11.6%), department of urology (9.8%) and department of neuro-surgery (9.1%). On the other hand, the lowest number was observed in the department of family medicine. The clinical material showing over 15% isolation rate against Staphylococcus spp. were 32.1% in urine (random urine and catheterized urine), 20.6% in blood and 16.0% in sputum.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.1
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• pp.38-44
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• 2006

A simple and easy modification of AST by disk diffusion was tested for the detection of induced clindamycin resistant Staphylococci and their antimicrobial susceptibility at the same time. The incidence of inducible clindamycin resistant staphylococci in blood culture and their MIC characterization at Seoul National University Hospital was analyzed by an AST contained disk approximation test (D-zone test) and Etest, respectively. Of the total 309 staphylococcal isolates, 139 (45%) isolates presented constitutive resistance to ERY and CLI (ERY-R, CLI-R phenotype), and 59 were ERY-I/R and CLI-S phenotypes. Of the 59 isolates, 19 (32%) isolates were inducible resistant to CLI. The incidence was higher in S. aureus (66.7%) than coagulase-negative staphylococci (CNS, 26.0%). Especially, methicillin-resistant staphylococci (MRSA, 100%; MRCNS, 45.5%) presented higher inducibility than methicillin susceptible (MSSA, 50%; MSCNS, 20%). For most of the inducible clindamycin resistant staphylococci (15 of 19 isolates), their ERY MIC were high (>$128_{\mu}g/mL$) and were methicillin resistant. The remaining 4 isolates were methicillin susceptible and their ERY MIC were of intermediate concentrations ($1-4_{\mu}g/mL$). We concluded that suscetibility testing of staphylococci, especially methicillin resistant, should include the D-zone test.

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.71-76
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• 1998

The effects of chitosan on mastitis in lactating holstein cows were evaluated. Fifty six cows with intramammary infection(IMI) from nine farms were selected and the cows were fed with diets which contained 15~20g chitosan per day for 5~7 days. The milk samples were obtained from cows at 7 days and 14 days after administration to determine effect of the curing of mastitis and the reduction of somatic cell counts(SCC). The average value of SCC levels in quarter milk from the cows administrated with chitosan significantly decreased up to 31.8% and 47.7% at 7 and 14 days, respectively(P<0.05). The cure rates of chitosan for Stapylococcus aureus, coagulase-negative Staphylococci, Streptococci spp, other gram positive bacteria and coliforms were 30.4, 42.8, 33.3, 66.6 and 54.5 % respectively. Twenty three out of 64 cases were cured by feeding with chitosan. The results showed that administration of chitosan could reduce SCC in milk and improve cure rates of bovine mastitis caused by microorganisms. The further studies will be pursued to study on the mechanism of chitosan in the immune responses of cows with mastitis.

• Journal of Environmental Health Sciences
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• v.28 no.1
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• pp.85-92
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• 2002

A measurement of indoor microorganism using Reuter Centrifugal Air Sampler(RCS) was undertaken during October 1991 - February 1999 and 6-Stage Cascade Air Sampler was undertaken during May 2001 - June 2001 in Seoul. Sites including book store, department store, theater, subway station, underground shopping center, hospital, office building, sports facility, and eduationa institutio were chosen to measure indoor microorganism. The results were as follows: 1. The average of total microorganism collected on the agar strip GK-A media were, in the order, subway station, hospital, underground shopping center, department store, book store, theater, sports facility, educational institution, office building in sites. The highest concentration of 711cfu/m$^3$ was found in the subway station and the lowest concentration of 44cfu/m$^3$ was found in office building. 2. The average of staphylococci collected on the agar strip GK-S media, in the order, were subway station, underground shopping center, hospital and department store, department store, theater, office building, sports facility and educational institution in sites. The highest concentration of 502cfu/m$^3$ was found in the subway station and the lowest concentration of 14cfu/m$^3$ was found in sports facility and educational institution. 3. The average of fungus collected on the agar strip GK-HS media, in the order, were underground hospital, shopping center, theater, subway station, department store, book store, sports facility, educational institution, and office building in sites. The highest concentration of 252cfu/m$^3$ was found in the hospital and the lowest concentration of 32cfu/m$^3$ was found in office building. 4. Ratio of Indoor/Outdoor, determined by site was 1.12-2.38 in total count, 1.00-2.35 in staphylococci, and 0.99-1.34 in fungus. 5. The positive results of test were 12-24% in indoor and 9-43% in outdoor. 6. By gram staining gram positive cocci were 59.9%, gram positive bacill 24.4%, gram negative bacilli 10.4%, and gram negative cocci 0.5%.

• YAKHAK HOEJI
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• v.51 no.2
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• pp.108-114
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• 2007

The predominant Macrolides-Lincosamide-Streptogramin B (MLS$_B$) antibiotics resistance genes in staphylococci are erm(A) and erm(C). There is the phenomenon that the ratio of constitutively MLS$_B$ antibiotics resistance (cMLS) in erm(A) is much higher than in erm(C). Thus, we confirmed that the difference of the mutation ratio between erm(A) and erm(C) makes the phenomenon. We examined 8 staphylococci carrying inducibly expressed (iMLS) erm(A) or erm(C) genes. After overnight incubation in the presence of the non-inducer MLS$_B$ antibiotics, spontaneous mutants constitutively expressed MLS$_B$ resistance were selected. Against our expectation, the mutation ratio of erm(A) was lower than erm(C). Therefore, possibilities of other factors determining the ratio of cMLS phenotype might be concerned. All the mutants showed sequence alterations in translational attenuator and all the alterations seemed to give rise to change the second structure of mRNA to express constitutively. For erm(A), 4 different types of sequence deletions ranging from 72 bp to 122 bp and 3 different types of duplications ranging 24 bp to 93 bp were detected. Also, there were 9 different types of duplications ranging 15bp to 154bp in erm(C).

• Journal of Microbiology
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• v.45 no.4
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• pp.286-290
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• 2007

The purpose of this study was to investigate the prevalence and genetic mechanisms of erythromycin resistance in staphylococci. A total of 102 erythromycin resistant non-duplicate clinical isolates of staphylococci [78. coagulase negative stapylococci (CNS), 24 Staphylococcus aureus] were collected between October 2003 and August 2004 in Istanbul Faculty of Medicine in Turkey. The majority of the isolates were from blood and urine specimens. Antimicrobial susceptibilities were determined by the agar dilution procedure and the resistance phenotypes by the double disk induction test. A multiplex PCR was performed, using primers specific for erm(A), erm(B), erm(C), and msrA genes.. Among the 78 CNS isolates, 57.8% expressed the $MLS_{B}-constitutive$, 20.6% the $MLS_{B}-inducible$, and 21.6% the $MS_B$ phenotypes. By PCR, 78.2% of these isolates harbored the erm(C) gene, 8.9% erm(A), 6.4% erm(B), and 11.5% msrA genes. In S. aureus, the constitutive $MLS_B$ (58.3 %) was more common than the inducible phenotype (20.8%). erm(A) was detected in 50% and erm(C) in 62.5% of the isolates, while 37.5% contained both erm(A) and erm(C). erm(C)-associated macrolide resistance was the most prevalent in CNS, while ermC) and erm(A, C) was the most prevalent in S. aureus.

• Parasites, Hosts and Diseases
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• v.46 no.3
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• pp.191-193
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• 2008

Cutaneous leishmaniasis (CL) is a parasitic disease characterized by single or multiple ulcerations. Secondary bacterial infections are one of the complications that can increase the tissue destruction and the resulting scar. To better determine the incidence of real secondary bacterial infections in CL, we designed the current study. This was a cross-sectional study performed in Skin Diseases and Leishmaniasis Research Centre, Isfahan, Iran. A total of 1,255 patients with confirmed CL enrolled in the study. Sterile swaps were achieved for ulcer exudates and scraping was used for non-ulcerated lesions. All samples were transferred to tryptic soy broth medium. After 24 hr of incubation at $37^{\circ}C$ they were transferred to eosin methylene blue agar (EMB) and blood agar. Laboratory tests were used to determine the species of bacteria. Among 1,255 confirmed CL patients, 274 (21.8%) had positive cultures for secondary bacterial infections. The bacteria isolated from the lesions were Staphylococcus aureus in 190 cases (69.3%), coagulase negative Staphylococcus in 63 cases (23.0%), E. coli in 10 cases (3.6%), Proteus sp. in 6 cases (2.2%), and Klebsiella sp. in 5 cases (1.9%). The results show that the overall incidence of secondary bacterial infections in the lesions of CL was 21.8%, considerably high. The incidence of secondary bacterial infections was significantly higher in ulcerated lesions compared with non-ulcerated lesions.