Hae In Bang, Jeong Won Shin, Tae Youn Choi, Rojin Park, Yu Jeong Shin
Ann Clin Microbiol 2010 December, 13(4): 147-150. Published on 20 December 2010.
Background: The pandemic swine origin influenza A/H1N1 2009 virus (H1N1 2009) was rapidly spread out all over the world after it was first found in April, 2009. This study was made to compare the performance of nasopharyngeal swabs and nasopharyngeal aspirates for the SD Bioline rapid influenza antigen test.
Methods: From Aug to Nov, 2009 the SD Bioline rapid influenza antigen tests were conducted with the nasopharyngeal swabs and the nasopharyngeal aspirates from the 244 specimens of patients who had come to the hospital with influenza-like illness. The data from the examination were compared with the multiplex RT-PCR as a reference standard to obtain sensitivity, specificity, positive predictive value and negative predictive value.
Results: The sensitivity and the specificity of the SD Bioline rapid influenza antigen tests with the nasopharyngeal swabs were 75.8%, and 93.3% respectively, and the sensitivity and specificity with the nasopharyngeal aspirates were 61.3%, and 98.3% respectively.
Conclusion: Even if the nasopharyngeal aspirates showed the lower sensitivity than the nasopharyngeal swabs, since the specificity is higher, the nasopharyngeal aspirates are more useful because we can reduce false positive rate.
[in Korean]
Jin Young Lee, Jong Hee Hong, Miae Lee
Ann Clin Microbiol 2010 December, 13(4): 151-156. Published on 20 December 2010.
Background: Blood culture bottles with an antimicrobial removal system have been developed for patients treated with antibiotics. This study compared the ability of BACTEC Plus Aerobic/F bottles (Becton Dickinson, USA, BACTEC Plus) and BacT/Alert FA bottles (bioMerieux Vitek, France) to effectively remove antimicrobials.
Methods: BACTEC Plus and BacT/Alert FA bottles were spiked with 5 mL human blood, peak therapeutic concentrations of 9 antimicrobials and 7 type strains. Three rounds of duplicate testing were completed per antimicrobial/strain combination and growth control without antimicrobials. The time to detection (TTD) and recovery rates for bacteria were compared for both systems.
Results: Overall, the BACTEC Plus and BacT/Alert FA recovered 76% (128/168) and 34% (57/168) of strains from test bottles, respectively. BACTEC Plus detected all of gram-positive bacteria except S. pneumoniae with ampicillin and ceftriaxone, but BacT/Alert FA detected 0∼50% of gram-positive bacteria except E. faecalis with vancomycin and methicillin-resistant S. aureus with oxacillin. In presence of cefepime, cefotaxime, cefoxitin and ceftriaxone, BACTEC Plus detected 33∼100% of gram-negative bacteria, but BacT/ Alert FA did not detect gram-negative bacteria at all. In presence of ciprofloxacin, BacT/Alert FA detected 100% of E. coli and K. pneumoniae compared with 33% of those for BACTEC Plus. Overall, TTD of BACTEC Plus was shorter than that of BacT/Alert FA except in detecting gram-negative bacteria with ciprofloxacin (P＜0.05).
Conclusion: BACTEC Plus Aerobic/F media containing peak therapeutic levels of antimicrobials are more effective and faster detection of bacteria than BacT/ Alert FA media.
[in Korean]
Mi Kyung Kim, Jong Hee Hong, Miae Lee
Ann Clin Microbiol 2010 December, 13(4): 157-161. Published on 20 December 2010.
Background: The Clinical and Laboratory Standards Institute (CLSI) recommends testing for inducible clindamycin resistance in clindamycin non-resistant and erythromycin resistant (CNR-ER) staphylococci by using a D-zone test. Recently, the VITEK2 system was developed to detect inducible clindamycin resistance in staphylococci. We evaluated the performance of the VITEK2 system by comparing it with a D-zone test.
Methods: In detecting inducible clindamycin resistance, a total of 142 clinical isolates of staphylococci were tested by using the VITEK2 Antimicrobial Susceptibility Test (AST)-P601 card (bioMérieux, Marcy l’Etoile, France) and the D-zone test. Of the 142 isolates of staphylococci tested, 114 were CNR-ER staphylococci [40 coagulase-negative staphylococci (CoNS), 74 Staphylococcus aureus] and 28 were staphylococci, either resistant or susceptible to clindamycin and erythromycin (1 CoNS and 27 S. aureus).
Results: Of the 114 CNR-ER staphylococci, 98.6% (73/74) of S. aureus and 32.5% (13/40) of CoNS were inducible clindamycin resistant according to the D- zone test. Overall sensitivity and specificity of the VITEK2 system were 98.8% (85/86) and 98.2% (55/56) respectively, and the agreement between the VITEK2 system and the D-zone test was 98.6% (140/142).
Conclusion: The VITEK2 system shows high concordance with a D-zone test. The inducible clindamycin resistance in staphylococci can be detected easily and conveniently by the VITEK2 system.
[in Korean]
Min-Chul Cho, Sin-Ae Noh, Mi-Na Kim, Kyoung-Mo Kim
Ann Clin Microbiol 2010 December, 13(4): 162-168. Published on 20 December 2010.
Background: Causative bacterial agents of infectious diarrheal disease were traditionally diagnosed by stool cultures. Stool culture, however, has a problem because of relatively low sensitivity and long turnaround time. In this study, we evaluated multiplex PCR applied on stool specimens directly to diagnose enteropathogenic bacteria.
Methods: From June to September 2009, 173 diarrheal stools submitted for stool cultures were tested by SeeplexⓇ Diarrhea ACE Detection kit (Seegene, Korea) to detect 10 enteropathogenic bacteria. Specimens were cultured for Salmonella, Shigella, Vibrio, and Yersinia. Late 50 specimens were also cultured for Campylobacter. The specimens positive for verotoxin-producing Escherichia coli (VTEC) were further subcultured for detecting enterohaemorrhagic Escherichia coli O157:H7. Electronic medical records were reviewed for clinical and laboratory findings.
Results: Of 173 specimens, multiplex PCR and cultures identified enteropathogens in 36 (20.8%) and 8 specimens (4.6%), respectively. While multiplex PCR detected 5 Salmonella, 15 Campylobacter, 1 Vibrio, 4 Clostridium difficiles toxin B, 5 Clostridium perfringens, 1 Yersinia enterocolitica, 5 Aeromonas, and 2 VTEC, cultures detected 5 Salmonella, 1 Vibrio, 1 Y. enterocolitica, 1 Aeromonas, and 2 E. coli O157:H7.
Conclusion: Multiplex PCR would be useful to detect Campylobacter, VTEC and C. perfringens, as well as have equivalent sensitivity to conventional culture for ordinary enteropathogens such as Salmonella, Shigella, Vibrio, Y. enterocolitica. Direct application of multiplex PCR combined with conventional cultures on stool warrants remarkable improvement of sensitivity to diagnose enteropathogenic bacteria.
[in Korean]
Nam Hee Ryoo, Jung Sook Ha, Dong Seok Jeon, Jae Ryong Kim
Ann Clin Microbiol 2010 December, 13(4): 169-172. Published on 20 December 2010.
Background: Metallo-β-lactamases (MBLs) have been reported in gram negative bacilli and are becoming increasingly important clinically because the enzymes hydrolyse almost all β-lactams, including carbapenems. Thus, the present study was conducted to determine the prevalence of MBL types in imipenem-nonsusceptible Pseudomonas aeruginosa and Acinetobacter baumannii isolated from a tertiary teaching hospital.
Methods: Imipenem-nonsusceptible strains, 128 P. aeruginosa and 93 A. baumannii, were collected from clinical specimens. Identification and susceptibility tests were determined by Vitek GNI and GNS cards. MBL production was determined by modified Hodge test and imipenem-EDTA synergy test. Multiplex PCR amplification of MBL genes including blaIMP-1, blaVIM-1 and blaVIM-2 were performed.
Results: Thirty-one P. aeruginosa (24.2%) isolates and 3 A. baumannii (3.2%) were found to be MBL producers. In P. aeruginosa, 20 (15.6%) and 11 (8.6%) isolates were positive for blaIMP-1 and blaVIM-2, respectively whereas 1 (1.0%) and 2 (2.2%) isolates in A. baumannii, respectively.
Conclusion: IMP-1 is more prevalent MBL type than VIM-2 among imipenem-nonsusceptible P. aeruginosa unlike in other studies. Larger numbers of isolates and sequential studies are strongly recommended for the useful evaluation and monitoring of MBL production in the hospital setting to infection-control.
Hye In Woo, Jang Ho Lee, Seung-Tae Lee, Chang-Seok Ki, Nam Yong Lee
Ann Clin Microbiol 2010 December, 13(4): 173-177. Published on 20 December 2010.
Microbacterium oxydans, a coryneform gram-positive bacillus, have been isolated from a wide variety of environmental sources and reported its pathogenic potential with increasing frequency in the last few years. Microbacterium comprises more than 60 species. 16S rRNA sequences in different Microbacterium species are highly conserved and the differences of biochemical characteristics between several species are unclear. As a result, identification of Microbacterium to species level has been difficult in most clinical microbiology laboratories. In this article, we report a case of catheter-related bacteremia caused by M. oxydans that was identified by 16S rRNA sequencing analysis and phenotypic characteristics in patient with diffuse large B-cell lymphoma.
[in Korean]
Koung-Sun Lee, Do-Sim Park, Ji-Hyun Cho, Hak-Yeol Kim, Young-Jin Lee
Ann Clin Microbiol 2010 December, 13(4): 178-181. Published on 20 December 2010.
Balantidium coli is the only largest ciliated protozoon known to infect human and nonhuman primates. Balantidiasis is a zoonotic disease and is acquired by humans via fecal-oral contact between pigs and humans. The clinical manifestation includes mainly gastrointestinal symptoms; diarrhea and abdominal pain, but in rare cases extraintestinal spread to lungs has been reported. A few reports of B. coli were found in vaginal secretion, skin, gastric juice, and omentum, but there have been no previous isolated cases in the respiratory tract in Korea. We reported that the first case of pneumonia caused by B. coli in Korea in an immunocompetent 40-year-old woman who displayed symptoms of chest discomfort and cough, and was cured with metronidazole.
[in Korean]
Jeong Tae Kim, Jae Hyeon Lee, Hye Soo Lee, Yong Gon Cho, Dal Sik Kim, Sam Im Choi, Soo Chul Cho
Ann Clin Microbiol 2010 December, 13(4): 182-186. Published on 20 December 2010.
Microscopic examination of peripheral blood smear (PBS) for detection of microorganisms is simple method that can be used for doctors to confirm the septicemia more swiftly and to select more specific therapy. But it is unusual to find microorganisms in PBS. We report a case of gram negative bacteremia diagnosed by PBS in a severe thrombocytopenic pediatric surgical patient. A 6-month and 2 week old baby with cyanosis was diagnosed congenital heart diseases such as transposition of great arteries, atrial septal defect, and patent ductus arteriosus. The infant underwent surgical operations and the postoperative platelet count progressively decreased in spite of transfusion of multiple platelet concentrates. We performed routine examination of a PBS for evaluation of severe thrombocytopenia. The PBS revealed severe thrombocytopenia, leukopenia with left shifted and some extracellular bacilli. Toxic granulations, toxic vacuoles and some bacilli were observed in the neutrophils. The bacilli were identified as Pseudomonas aeruginosa and Serratia marcescens in blood culture. To our knowledge, this is the second case of bacteremia diagnosed by PBS before the positive blood culture in Korea. We suggest that a PBS is useful for the rapid detection of organisms in cases of septicemia with severe thrombocytopenic pediatric surgical patient.
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