A Case of Lambda-expressing Pulmonary MALT Lymphoma with Dual Clonal Rearrangements of Kappa and Lambda Immunoglobulin Light Chain Gene / 대한진단검사의학회지

A 70-yr-old woman was hospitalized with a history of dry cough. Bronchial endoscopy and transbronchial lung biopsy were performed. However, the findings of histopathology and immunohistochemistry were not sufficient to decide whether the lesion was benign or malignant, because of the presence of crush artifacts in the biopsy specimens. We performed B-cell clonality studies using BIOMED-2 multiplex PCR (InVivoScribe Technologies, USA) to detect clonal rearrangements in the immunoglobulin gene. The results of multiplex PCR showed clonal rearrangements of both kappa and lambda immunoglobulin light chain genes. The findings of immunochemistry revealed that the lesion expressed lambda light chain, but not kappa light chain. Based on the clinical, pathologic, and molecular findings, this case was diagnosed as pulmonary MALT lymphoma. We report the first case in Korea of lambda-expressing MALT lymphoma that is shown to have dual clonal rearrangements of kappa and lambda immunoglobulin light chain gene by multiplex PCR.

Epidemiological Investigation of an Outbreak of Escherichia coli Infections in Neonatal Intensive Care Unit of a University Hospital / 대한임상미생물학회지

BACKGROUND: In July 2007, three neonates in the neonatal intensive care unit (NICU) of Chosun University Hospital expired due to Escherichia coli sepsis. An E. coli outbreak was suspected. METHODS: To investigate the outbreak, environmental cultures were taken from NICU. We performed repetitive extragenic palindromic (rep)-PCR to compare genotypes of the three isolates from the cases and one environmental strain of E. coli. A case-control study was done in order to identify risk factors for the infection. RESULTS: In July 2007, the attack rate of E. coli was 11.1%, which was higher than the basal rate. All the three E. coli isolates from the cases presented the same antimicrobial susceptibility pattern whereas other E. coli isolated from non-outbreak period presented different patterns. Among environmental cultures, only one specimen collected from the surface of a bathtub for neonates was culture positive for E. coli. Three strains of the cases and one environmental strain of E. coli showed the same rep-PCR pattern, while control strains showed different patterns. No statistically significant difference in risk factors was found between the case and control groups in the case-control study. CONCLUSION: The result of rep-PCR assay showed that the outbreak had originated from a single clone of E. coli. But we could not identify risk factors for the infection. The attack rate of E. coli in NICU returned to the basal level after implement of the infection control measures such as disinfection of NICU environment and equipments, thorough hand washing, and education of health care workers.

A Strain of Nocardia cyriacigeorgica Isolated from a Patient with Pulmonary Infection / 대한임상미생물학회지

Nocardia cyriacigeorgica is an aerobic gram-positive rod that has mostly been reported as an opportunistic pathogen. Since molecular methodologies were introduced to identify species, infections caused by N. cyriacigeorgica have been reported. The patient was a 51-year-old woman with aplastic anemia, systemic lupus erythematosus, and disseminated tuberculosis, who was admitted to Chosun University Hospital with a history of fever and productive cough. During her hospitalization, sputum cultures were taken and a bacterium suspicious of acitinomycetes grew five times. It was a gram-positive rod that was also partially acid-fast on modified Kinyoun stain and resistant to lysozyme. After 24 h of incubation, cultures of the sputum onto sheep's blood agar plates (BAP) demonstrated rough, chalky, and white colonies with a characteristic earthy odor. Based on the above results, the presumptive identification of Nocardia species was made. To identify species of this isolate, 16S rRNA gene sequence analysis was taken and showed 99.9% homology to N. cyriacigeorgica DSM44484(T). The results of biochemical tests were compatible with other reports of N. cyriacigeorgica. As a result, this isolate was identified as N. cyriacigeorgica. Herein, we present a first report of N. cyriacigeorgica isolated from a patient with pulmonary infection in Korea.

Prevalence of Carbapenemase and Integrase Genes in Imipenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa Collected over Several Years in a University Hospital / 대한임상미생물학회지

BACKGROUND: The incidence of infections with imipenem- resistant Acinetobacter baumannii (IRAB) and Pseudomonas aeruginosa (IRPA) is increasing worldwide, and recent molecular studies indicate that the prevalence of carbapenemases is increasing in various parts of the world. However, few long-term longitudinal studies have assessed the prevalence of IRAB- and IRPA-derived carbapenemases and integrases in a hospital setting in Korea. METHODS: The carbapenemase genes (blaOXA-23, blaOXA-24, blaOXA-58, blaIMP-1, blaVIM-2, blaSIM-1, blaSPM-1) and integrase genes (intI1, intI2, intI3) produced by 46 IRAB strains and 51 IRPA strains collected at Chosun University Hospital between 2003 and 2006 were determined by PCR. RESULTS: The IRAB strains produced class 1 integrases more often than did the IRPA strains. However, the incidence increased steadily in both strains, reaching 100% in 2006. Carbapenemases of blaIMP-1 and blaVIM-2 types were found in 57% and 64% of the IRAB strains, respectively, in 2003. However, only one strain with blaVIM-2 was found in 2004 and another one with blaIMP-1 in 2005. The prevalence of carbapenemases was very low in the IRPA strains, just one strain with blaVIM-2 in 2005 and another one with blaoxa-23 in 2006. No other types of carbapenemase genes were detected in both strains. Rep-PCR of IRAB strains in 2003 showed different patterns. CONCLUSION: The incidence of carbapenemase varied by year but was generally low, except in 2003. The prevalence of class 1 integrases was consistently high and increased every year. The reason for the high prevalence of carbapenemases in 2003 is still unknown, but we assumed that it was not from the spread of a clone containing either blaIMP-1 or blaVIM-2 because the strains exhibited different rep-PCR patterns.