PURPOSE: Clostridium difficile (C. difficile) is an important cause of nosocomial diarrhea. Diagnostic methods for detection of C. difficile infection (CDI) are shifting to molecular techniques, which are faster and more sensitive than conventional methods. Although recent advances in these methods have been made in terms of their cost-benefit, ease of use, and turnaround time, anaerobic culture remains an important method for detection of CDI. MATERIALS AND METHODS: In efforts to evaluate a novel chromogenic medium for the detection of C. difficile (chromID CD agar), 289 fecal specimens were analyzed using two other culture media of blood agar and cycloserine-cefoxitin-fructose-egg yolk agar while enzyme immunosorbent assay and polymerase chain reaction-based assay were used for toxin detection. RESULTS: ChromID showed the highest detection rate among the three culture media. Both positive rate and sensitivity were higher from chromID than other culture media. ChromID was better at detecting toxin producing C. difficile at 24 h and showed the highest detection rate at both 24 h and 48 h. CONCLUSION: Simultaneous use of toxin assay and anaerobic culture has been considered as the most accurate and sensitive diagnostic approach of CDI. Utilization of a more rapid and sensitive chromogenic medium will aid in the dianogsis of CDI.
Chromogenic Compounds/chemistry ; Clostridium difficile/chemistry/*isolation & purification ; Culture Media/*chemistry

Breast Neoplasms ; chemistry ; genetics ; Chromogenic Compounds ; Female ; Genes, erbB-2 ; Humans ; In Situ Hybridization ; methods ; Receptor, ErbB-2 ; analysis

Breast Neoplasms ; metabolism ; pathology ; Chromogenic Compounds ; Female ; Humans ; Immunohistochemistry ; methods ; In Situ Hybridization ; methods ; In Situ Hybridization, Fluorescence ; methods ; Practice Guidelines as Topic ; Receptor, ErbB-2 ; metabolism ; Societies, Medical ; United States

We evaluated the performance of a new chromogenic medium for detection of Clostridium difficile, chromID C. difficile agar (CDIF; bioMerieux, France), by comparison with BBL C. difficile Selective Agar (CDSA; Becton Dickinson and Company, USA). After heat pre-treatment (80degrees C, 5 min), 185 diarrheal stool samples were inoculated onto the two media types and incubated anaerobically for 24 hr and 48 hr for CDIF and for 48 hr and 72 hr for CDSA. All typical colonies on each medium were examined by Gram staining, and the gram-positive rods confirmed to contain the tpi gene by PCR were identified as C. difficile. C. difficile was recovered from 36 samples by using a combination of the two media. The sensitivity with CDIF 48 hr was highest (100%) and was significantly higher than that with CDIF 24 hr (58.3%; P<0.001), because samples with a low burden of C. difficile tended to require prolonged incubation up to 48 hr (P<0.001). The specificity of CDIF 24 hr and CDIF 48 hr (99.3% and 90.6%, respectively) was significantly higher than that of CDSA 48 hr and CDSA 72 hr (72.5% and 67.1%, respectively; P<0.001). CDIF was effective for detecting C. difficile in heat-pretreated stool specimens, thus reducing unnecessary testing for toxin production in non-C. difficile isolates and turnaround time.
Agar/chemistry ; Bacterial Proteins/genetics ; Bacteriological Techniques/*methods ; Chromogenic Compounds/chemistry/metabolism ; Clostridium difficile/genetics/*isolation & purification ; Culture Media/chemistry ; DNA, Bacterial/analysis/metabolism ; Diarrhea/microbiology/pathology ; Feces/*microbiology ; Humans ; Polymerase Chain Reaction ; Time Factors

BACKGROUND: Accurate and early detection of vancomycin-resistant enterococci (VRE) is critical for controlling nosocomial infection. In this study, we evaluated the usefulness of a selective chromogenic agar medium and of multiplex PCR for detection of VRE, and both these techniques were compared with the conventional culture method for VRE detection. METHODS: We performed the following 3 methods for detecting VRE infection in stool specimens: the routine culture method, culturing in selective chromogenic agar medium (chromID VRE, bioMerieux, France), and multiplex PCR using the Seeplex(R) VRE ACE Detection kit (Seegene Inc., Korea) with additional PCR for vanC genes. RESULTS: We isolated 109 VRE strains from 100 stool specimens by the routine culture method. In chromID VRE, all the isolates showed purple colonies, including Enterococcus gallinarum and E. raffinosus, which were later identified using the Vitek card. All VRE isolates were identified by the multiplex PCR method; 100 were vanA-positive E. faecium, 8 were vanA- and vanC-1-positive E. gallinarum, and 1 was vanA-positive E. raffinosus. CONCLUSIONS: For VRE surveillance, culturing the isolates in chromID VRE after broth enrichment appears to be an accurate, rapid, and easy method for routine screening test. Multiplex PCR is relatively expensive and needs skilled techniques for detecting VRE, but it can be an auxiliary tool for rapid detection of genotype during a VRE outbreak.
Agar/chemistry ; Chromogenic Compounds/*chemistry ; Enterococcus/drug effects/genetics/*isolation & purification ; Enterococcus faecium/genetics/isolation & purification ; Feces/microbiology ; Genotype ; Humans ; Phenotype ; Polymerase Chain Reaction/*methods ; Reagent Kits, Diagnostic ; *Vancomycin Resistance

BACKGROUND: The incidence of Bacillus cereus bacteremia is increasing, but the identification of Bacillus species remains difficult. Brilliance Bacillus cereus agar (BBC agar; Oxoid, UK) is a new CHROMagar medium that allows selective isolation and identification of B. cereus; however, its clinical usefulness is seldom studied. We evaluated the usefulness of BBC agar to identify B. cereus isolates recovered from blood cultures. METHODS: We analyzed a total of 53 blood isolates that showed a Bacillus-like morphology on Gram staining. All isolates were identified by using both the API Coryne (bioMerieux, France) and API 50CH/B (bioMerieux) systems. They were subsequently subcultured on BBC agar, incubated for 24 hr, and then examined for characteristic blue-green colonies. The clinical characteristics of patients whose isolates were identified as B. cereus were assessed. RESULTS: Of the 53 isolates, 18 were identified as B. cereus by API 50CH/B. With the API 50CH/B system used as gold standard, the sensitivity and specificity for the identification of B. cereus were 100% (18/18) and 100% (35/35), respectively, using BBC agar, and 67% (12/18) and 100% (35/35), respectively, using the API Coryne system. Of the 18 patients with B. cereus bacteremia, 15 showed infectious signs, and 3 had more than 2 blood cultures positive for B. cereus on separate days. CONCLUSIONS: Our study shows, for the first time, that BBC agar, with its good agreement and ease of use, is a valuable alternative to the API 50CH/B system for the presumptive identification of B. cereus isolates from blood cultures.
Adolescent ; Adult ; Agar/chemistry ; Aged ; Bacillus cereus/*isolation & purification ; Bacteremia/*diagnosis/microbiology ; Child ; Child, Preschool ; Chromogenic Compounds/*chemistry ; Culture Media ; Female ; Gram-Positive Bacterial Infections/*diagnosis/microbiology ; Humans ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Reagent Kits, Diagnostic ; Sensitivity and Specificity

The specimens of ductal carcinoma in situ (DCIS) with early invasion, and specimens collected by core needle biopsy (CNB) tend to contain limited amount of invasive component, so it is imperative to explore a new technique which can assess HER2 gene status accurately for the limited invasive cancer component in these specimens. Dual staining technique of combining immunohistochemistry (IHC) for myoepithelial cells and single or dual probe chromogenic in situ hybridization (CISH) for HER2 gene was performed on routinely processed paraffin sections from 20 cases diagnosed as having DCIS with invasive cancer. Among them, 10 had fluorescence in situ hybridization (FISH)-confirmed amplification of HER2 and 10 had FISH-confirmed non-amplification of HER2. We successfully detected HER2 genetic signals and myoepithelial IHC markers (SMM-HC or CK5/6) simultaneously on a single section in all 20 specimens. Myoepithelial markers and HER2 signals detected by dual staining assay were consistent with those by individual technique performed alone. HER2 gene amplification results determined by dual staining assay were 100% consistent with those of FISH. Dual staining technique which allows simultaneous detection of myoepithelial marker protein and cancerous HER2 gene is feasible, and it has potential to be used in clinical practice for effective determination of HER2 amplification in limited invasive component.
Biomarkers, Tumor ; metabolism ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Chromogenic Compounds ; Female ; Gene Expression Profiling ; methods ; Humans ; Immunohistochemistry ; methods ; In Situ Hybridization, Fluorescence ; methods ; Neoplasm Invasiveness ; pathology ; physiopathology ; Receptor, ErbB-2 ; genetics ; metabolism ; Reproducibility of Results ; Sensitivity and Specificity

OBJECTIVETo evaluate the sensitivity and specificity of chromogenic in-situ hybridization (CISH) in detecting HER2 gene amplification in breast carcinomas.

METHODSHER2 oncogene amplification and its protein expression in 165 cases of breast carcinoma were investigated by immunohistochemistry (IHC) and CISH.

RESULTS(1) CISH did not detect HER2 gene amplification in 107 cases of IHC negative tumors and 24 cases of IHC 1+ tumors. (2) CISH identified high copy numbers of HER2 gene amplification in 21/22 (95.5%) cases with IHC 3+. (3) In 12 HIC 2+ cases, CISH identified 3 cases of high copy number amplification, 6 cases of low copy number amplification and 3 cases without amplification.

CONCLUSIONSHER2 gene amplification detection by CISH is highly sensitive and has a high concordance with IHC detection of the protein expression. It is concluded that CISH is a tool to evaluate HER2 gene status in breast cancer and can be an implement in conventional pathology laboratories.

Breast Neoplasms ; genetics ; metabolism ; pathology ; Carcinoma, Ductal, Breast ; genetics ; metabolism ; pathology ; Carcinoma, Intraductal, Noninfiltrating ; genetics ; metabolism ; pathology ; Carcinoma, Lobular ; genetics ; metabolism ; pathology ; Chromogenic Compounds ; Female ; Gene Amplification ; Humans ; Immunohistochemistry ; methods ; In Situ Hybridization ; methods ; Receptor, ErbB-2 ; genetics ; metabolism

BACKGROUND: We evaluated the performance of three chromogenic media (Brilliance agar I [Oxoid, UK], Brilliance agar II [Oxoid], and ChromID MRSA [Biomerieux, France]) combined with broth enrichment and the Xpert MRSA assay for screening of methicillin-resistant Staphylococcus aureus (MRSA). METHODS: We obtained 401 pairs of duplicate nasal swabs from 321 patients. One swab was suspended overnight in tryptic soy broth; 50-microL aliquots of suspension were inoculated on the three chromogenic media. Brilliance agar I and II were examined after 24 hr, and ChromID MRSA, after 24 and 48 hr. The paired swab was processed directly using real-time PCR-based Xpert MRSA assay. RESULTS: True positives, designated as MRSA growth in any of the culture media, were detected with the prevalence of 17% in our institution. We report the sensitivity, specificity, positive predictive value, and negative predictive value of MRSA growth as follows: 92.3%, 94.0%, 75.9%, and 98.4% in Brilliance agar I (24 hr); 92.7%, 97.9%, 90.0%, and 98.5% in Brilliance agar II (24 hr); 95.6%, 95.8%, 82.3%, and 99.1% in ChromID MRSA (24 hr); 100%, 92.5%, 73.1%, and 100% in ChromID MRSA (48 hr); 92.6%, 96.7%, 85.1%, and 98.5% in Xpert MRSA assay. The agreement between the enriched culture and Xpert MRSA assay was 96.0%. CONCLUSIONS: Three chromogenic culture media combined with enrichment and Xpert MRSA assay demonstrated similar capabilities in MRSA detection. The Xpert MRSA assay yielded results comparable to those of culture methods, saving 48-72 hr, thus facilitating earlier detection of MRSA in healthcare settings.
Bacterial Proteins/genetics ; Bacterial Typing Techniques/*methods ; Chromogenic Compounds/chemistry/*metabolism ; Culture Media/chemistry ; DNA, Bacterial/analysis ; Humans ; Methicillin-Resistant Staphylococcus aureus/*genetics/growth & development/*isolation & purification/metabolism ; Nasal Cavity/*microbiology ; Reagent Kits, Diagnostic ; *Real-Time Polymerase Chain Reaction ; *Staphylococcal Infections/diagnosis/microbiology

The significant advance in the development of molecular-targeting drugs has made an evaluation of Her-2, EGFR, and cyclin D1 an important clinical issue in breast cancer patients. This study compared the Her-2, EGFR, and cyclin D1 status of primary tumors as well as their matching lymph node metastases using immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH) in 73 breast cancer patients. Her-2, EGFR, and cyclin D1 protein showed a concordance between the primary lesion and the metastatic regional lymph nodes in 82%, 90%, and 63%, respectively. CISH also revealed 92%, 93%, and 85% concordance in the gene amplification status of Her-2, EGFR, and cyclin D1, showing a reasonable agreement between primary tumors and metastatic regional lymph nodes. Although a statistically significant agreement was found in Her-2 expression, a relatively high discordance rate (18%) raises a little concern. Our findings suggest that the Her-2 status can be reliably assessed on primary tumor but a possible difference can be found in Her-2, EGFR, and cyclin D1 status between the primary and the metastatic sites and this possibility should be concerned in patients considering molecular targeted therapy or patients with progress of disease.
Adult ; Aged ; Breast Neoplasms/genetics/*metabolism/pathology ; Chromogenic Compounds ; Cyclin D1/*analysis/genetics ; Female ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Lymph Nodes/*metabolism/pathology ; Lymphatic Metastasis ; Male ; Middle Aged ; Neoplasm Recurrence, Local/genetics/metabolism ; Receptor, Epidermal Growth Factor/*analysis/genetics ; Receptor, erbB-2/*analysis/genetics ; Survival Analysis