BACKGROUND: It takes long time to cultivate Mycobacterium tuberculosis on solid media from clinical specimens. Although there is progress in the detection of tuberculosis using liquid media, Ogawa media is broadly used in Korea. In the 1990s, the BACTEC 460 system (Becton Dickinson, Sparks, MD, USA) was used in some laboratories in Korea, but at present, it is not used because of the accumulation of radioactive waste and the risk of cross-contamination. The BACTEC MGIT 960 system (Becton Dickinson, Sparks, MD, USA) is one of the new systems using liquid media. MGIT system uses oxygen-quenching fluorescence sensor technology instead of radioactive material. We evaluated MGIT for the sensitivity and specificity for the diagnosis of Mycobacterium tuberculosis by comparison with Ogawa media. METHODS: A total of 232 sputum specimens were collected from patients admitted to the hospital. All specimens were processed by 4% NaOH and 0.5% NALC. After inoculation of MGIT with 0.5 mL and Ogawa with 0.3 mL of the processed specimen, the media were observed every 3 days until 6 weeks and 8 weeks, respectively. RESULTS: A total of 99 isolates of mycobacteria were recovered from 232 specimens. Ninety nine isolates were detected with MGIT, as contrasted with 64 detected with Ogawa media. The mean times to detection of the Mycobacterium species were 12.6 days for MGIT, 23.7 days for Ogawa media. Contamination rates were 5.1% for MGIT, 5.6% for Ogawa media. CONCLUSION: From our study, we conclude that MGIT is a superior method for recovery rate and time to detection of Mycobacteria to Ogawa media.
Diagnosis ; Fluorescence ; Humans ; Korea ; Mycobacterium ; Mycobacterium tuberculosis ; Radioactive Waste ; Sensitivity and Specificity ; Sputum ; Tuberculosis

BACKGROUND: Increase of immunocompromised patients and frequent use of indwelling catheters cause staphylococcal bacteremia, especially due to coagulase-negative staphylococci (CNS), in contrast with Staphylococcus aureus in the past. And, infections of methicillin-resistant staphylococci have been increasing in number from 1970s. In this study, species of staphylococcal isolates from blood were demonstrated, and their methicillin susceptibilities were evaluated for the empirical choice of antibiotics. METHODS: One hundred and seventy-five staphylococcal strains isolated from blood culture at Pusan National University Hospital during the year 1999 were included. Species identification, susceptibility tests by agar dilution and disk diffusion methods, and mecA gene detection by polymerase chain reaction were performed. RESULTS: S. aureus (41%), S. epidermidis (30%), S. auricuralis, S. intermedius, S. haemolyticus, S. capitis, S. simulans, S. sciuri, S. homis, and S. warneri were identified. Thirty-one stains (43.4%) of S. aureus, 43 stains (83%) of S. epidermidis, and 24 stains (46%) of other CNS are resistant to oxacllin. The results of disk diffusion test were consistant with agar dilution tests in all S. aureus strains and 95.5% of CNS strains. The results of mecA gene detection were consistant with agar dilution methods in 96.8% of S. aureus and 89.6% of CNS. CONCLUSIONS: Not only S. aureus and S. epidermidis but also other various species of staphylococci were recovered from blood, and methicillin-resistant strains reached 43.2% of S. aureus, and 64.4% of CNS. These results would help for physicians to choose primary empirical therapeutic agents of patients who are suggestive of staphylococcal bacteremia.
Agar ; Anti-Bacterial Agents ; Bacteremia ; Busan ; Catheters, Indwelling ; Coloring Agents ; Diffusion ; Humans ; Immunocompromised Host ; Methicillin ; Methicillin Resistance ; Oxacillin* ; Polymerase Chain Reaction ; Staphylococcus ; Staphylococcus aureus

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is the most common nosocomial pathogen, which is particularly prevalent in intensive care units (ICUs). We performed this study to investigate the modes of transmission of MRSA and the role of nasal carriage of MRSA to subsequent MRSA infection in ICU. METHODS: From September to November 1997, all patients admitted for more than two days to the ICU were studied prospectively. Nasal swabs were obtained at admission and weekly during the ICU stay. Surveillance cultures of nares of the ICU personnels were done. Molecular typing was performed with repetitive sequence-based PCR (rep-PCR). RESULTS: At ICU admission 34 patients (21.0%: 19 MSSA, 15 MRSA) were MRSA nasal carrier, while 126 patients were free of nasal colonization. During the ICU stay 12 (9.5%: 3 MSSA, 9 MRSA) of the 126 noncolonized patients became nasal carriers (P <0.05). S. aureus infections (all MRSA) were documented in 14 (15 isolates, 8.6%) of the total 162 patients. S. aureus infections were significantly higher for those patients who were nasal carriers at ICU admission than for those found to be initially negative (P <0.05). Two different type (A, 7 isolate; B, 8 isolates) of rep-PCR patterns were identified. All four nasal and seven clinical isolates from the patients, and four nasal isolates from the ICU personnels were mixed with A and B patterns, respectively. CONCLUSION: Nasal colonization was related to the increased incidence of MRSA infections. Patients or ICU personnels who were nasal colonized with MRSA seemed to be a major source for transmission of MRSA in the ICU.
Colon ; Humans ; Incidence ; Intensive Care Units* ; Critical Care* ; Methicillin Resistance* ; Methicillin-Resistant Staphylococcus aureus* ; Molecular Typing ; Polymerase Chain Reaction ; Prospective Studies

BACKGROUND: Mycobacterial false-positive cultures have rarely been recognized in Korea, even though the rate of false-positive cultures of Mycobaterium tuberculosis has ranged from 0.4% to 4.0%. We estimated the false-positive rates by the review of medical records from whom mycobacterial cultures were requested, retrospeaively, after a bout of false-positive cultures was discovered in specimens treated in a single day. METHODS: Of the total 2,245 specimens, including 337 positive cultures of mycobacteria, during the period of January and June 1999, seventy-two specimens that showed colonies less than or equal to 5 colonies were reviewed, and classified as tuberculosis-likely group, tuberculosis-unlikely group and unclassifiable group by the clinical and radiological evidences, anti-tuberculosis therapy, and microbiological results. RESULTS: Tuberculosis-unlikely group was 21 specimens from 20 patients, and unclassifiable group was five specimens from four patients. So, the false-positive rates were estimated as 0.9- 1.1% of total cultures and 6.2-7.7% of positive cultures, according to excluding or including the unclassifiable group. CONCLUSION: Care should be taken for lowering false-positive mycobacterial cultures. Especially when a culture turned out to be positive with low colony isolates, more careful interpretations should be preceded before reporting the results by the review of medical records and communication with physician in charge.
Humans ; Incidence* ; Korea ; Medical Records ; Mycobacterium tuberculosis* ; Mycobacterium* ; Tuberculosis

BACKGROUND: Aspergillus species are second only to Candida species as the most commonly isolated fungi from clinical specimens. As well as the identification of the Aspergillus species, it has been necessary for epidemiological studies to differentiate between strains of the same species. We performed genotypic identification and characterization of species and strains within the genus Aspergillus by using RAPD. METHODS: A total of 63 clinical strains of Aspergillus species (including 21 A. fumigatus, 12 A. flavus, 12 A. niger, 12 A. terreus, 3 A. nidulans, and 3 A. sydowii) from 63 patients was analyzed. For RAPD alanysis, M13 primer (5'GAGGGTGGCGGTTCT3') and five random 10-mer primers (OPC-6, 7, 10, 18 and 20; Operon Technologies, USA) were used. RESULTS: The RAPD patterns by M13 primer appeared to be identical when the isolates of the same Aspergillus species were compared. Distinctive and reproducible sets of amplification products by primer M13 were observed for different Aspergillus species: 60 of 63 (95%) isolates were correctly identified by the RAPD analysis using primer M13. RAPD patterns obtained from different strains of the same Aspergillus species by five OPC primers were far more similar than those derived from different Aspergillus species, but the RAPD profiles with some OPC primers showed polymorphism among isolates of the same Aspergillus species. The application of some OPC primers made it possible to cluster the isolates of the same Aspergillus species into several groups. CONCLUSION: These results indicate that RAPD can be useful for the rapid identification of Aspergillus species and for strain typing in the epidemiological investigations.
Aspergillus* ; Candida ; DNA* ; Epidemiologic Studies ; Fungi ; Genotype ; Humans ; Niger ; Operon

BACKGROUND: Vibrio species may be classified as halophilic or nonhalophilic on the basis of their requirement of NaCl for optimal growth. Recently, attention has been focused on the halophilic vibrios and Vibrio cholerae non-O1/O139 causing extraintestinal infections such as septicemia. The aim of this study is to elucidate the isolation rate and clinical manifestations of Vibrio species isolated from clinical specimens between 1996 and 2000 at Wonju Christian Hospital. METHODS: Stool specimens were inoculated onto the thiosulfate-citrate-bile salt-sucrose media, blood cultures were performed by automated blood culture systems with commercial bottles, and the others were cultured according to the routine procedures. RESULTS: The isolation rate of Vibrio in decreasing order were: V. parahaemolyticus; 87%(62/71), V. alginolyticus; 6%(4/71), V. cholerae non-O1; 4%(3/71), and V. vulnificus; 3%(2/71). The proportions of gastroenteritis and septicemia by Vibrio species were 89% and 7%, respectively. Patients with gastroenteritis recovered without special problem, but the mortality of septicemia was 80%. CONCLUSIONS: Ninety-seven percentage of clinical isolates of Vibrio species were halophilic vibrios, and the mortality of Vibrio septicemia was as high as 80%.
Cholera ; Gangwon-do* ; Gastroenteritis ; Humans ; Mortality ; Sepsis ; Tertiary Healthcare* ; Vibrio cholerae ; Vibrio Infections* ; Vibrio*

BACKGROUND: Although most of aerobic gram-positive bacilli have been considered to be contaminants, gram-positive bacilli should be identified to the species level if they are isolated from sterile body sites such as blood, and from adequately collected clinical specimens if they are the predominant organisms. However, identification of gram-positive bacilli are difficult due to the enormous diversity of these organisms and the small number of readily available commercial identification systems in clinical laboratories. Gram-positive bacilli and coccorods isolated from blood cultures were tested with BBL Crystal Gram-Positive (GP) Identification (ID) system in order to evaluate the system's usefulness of identifying these bacteria. METHODS: Thirty-seven stock strains of aerobic gram-positive bacteria isolated from blood cultures between October 1998 and November 1999 at Wonju Christian Hospital were simultaneously tested by BBL Crystal GP ID system and API system. Three kinds of API system (API Coryne, API 50 CHB, and API 20 Strep) were tested according to gram stain results. Gram-positive bacilli or gram-positive coccorods consecutively isolated from blood cultures from May to November in 2000 were identified by BBL Crystal GP ID system. RESULTS: Among the 37 stock strains of aerobic gram-positive bacteria, agreement rate of identification between Crystal GP ID system and API system were 88% to the genus level and 63% to the species level in Bacillus species, and 90% to the genus level in Corynebacterium species. The isolation rate of gram-positive bacteria from blood cultures from May to November in 2000 to the genus level were: Bacillus; 41.9%(18/43), Corynebacterium; 37.2%(16/43), and the other grampositive coccorods; 20.9%(9/43). CONCLUSIONS: Crystal GP ID system is a useful identification system which, when combined with basic microbiological tests, should lead to satisfactory identification results for gram-positive bacteria isolated from blood cultures.
Bacillus ; Bacteria ; Corynebacterium ; Gangwon-do ; Gram-Positive Bacteria*

BACKGROUND: Macrolide resistance in beta-hemolytic streptococci has increased during the 1990s, and the proportion of MLS (Macrolide-lincosamide-streptogramin) resistance phenotypes and genotypes of beta-hemolytic streptococci are quite different by geographical variation and study period. The aim of the present study was to determine the distribution of MLS resistance phenotypes and genotypes in beta-hemolytic streptococci isolated from Wonju Christian Hospital. METHODS: The minimal inhibitory concentrations of erythromycin and clindamycin of 426 beta- hemolytic streptococci isolated from clinical specimens between 1990 to 1999 were determined by agar dilution method. MLS resistance phenotypes were determined by double disk diffusion method using erythromycin and clindamycin disk, and genotypes were determined by polymerase chain reaction (PCR). The PCR primers for erm(A), erm(B), erm(C), erm(TR), and mef(A) were used in these study. RESULTS: The proportion of MLS resistance phenotypes of 80 erythromycin-resistant beta-hemolytic streptococci were 60.0% for constitutive phenotype, 23.8% for M phenotype, and 16.2% for inducible phenotype. The proportion of three MLS resistance phenotypes of group A streptococci were nearly equal. About three-fourths of group B streptococci had the constitutive phenotypes, whereas three-fourths (75%) of group G streptococci had the M phenotypes. All MLS resistant strains carried the erm(B) genes in constitutive phenotypes, erm(TR) genes in inducible phenotypes, and mef(A) genes in M phenotypes, respectively. CONCLUSIONS: Mechanisms and phenotype proportions of MLS resistance are different by species in beta-hemolytic streptococci. It is possible that MLS resistance genes have transferred among beta- hemolytic streptococci because the erythromycin resistance genes are the same in beta-hemolytic streptococci.
Agar ; Clindamycin ; Diffusion ; Erythromycin ; Gangwon-do ; Genotype ; Phenotype ; Polymerase Chain Reaction

BACKGROUNDS: Culture of Helicobacter pylori (H. pylori) from gastric biopsy specimens is a standard method with high specificity among H. pylori diagnostic tools and is also essential for antibiotic susceptibility test. The authors compared 5 selective media for H. pylori culture and tested fresh human serum instead of fresh animal blood as a media composite. METHODS: Gastric biopsy specimens from endoscopic examination were obtained from 50 patients (gastric ulcer:33, duodenal ulcer:12, stomach cancer:5) and they were finely minced with a tissue grinder. Specimens were inoculated onto 5 media (1. Columbia agar with 5% sheep blood, 2. Columbia agar with 10% human serum, 3. Thayer-Martin agar with 5% sheep blood, 4. T-M agar with 10% human serum, 5. T-M agar with 10% hemoglobin) and cultured for 3~7 days under microaerophilic condition. Gram stain, oxidase, catalase, and urease tests, were undertaken on typical colonies for diagnosis of H. pylori. Contamination by other organisms, number and size of H. pylori colonies were compared for each media. RESULTS: Positive culture rate of H. pylori was not significantly different among 4 media except TM agar with 10% hemoglobin. However T-M agar with 10% fresh human serum was considered as the best composition for culture of H. pylori because it had the least contaminating organisms and produced the largest colony sizes. CONCLUSIONS: These findings suggest that T-M agar with 10% fresh human serum can replace columbia agar with 5% sheep blood which has been commonly used for culture of H. pylori from gastric biopsy specimens. Fresh human serum, which is easily obtained in the clinical laboratory, can replace animal bloods in making media for H. pylori.
Agar ; Animals ; Biopsy ; Catalase ; Diagnosis ; Helicobacter pylori* ; Helicobacter* ; Humans ; Oxidoreductases ; Sensitivity and Specificity ; Sheep ; Stomach ; Urease

No abstract available.
Salmonella Infections*