Jeong-Sook Kim, Hanvit Seok, Sunjoo Kim
Ann Clin Microbiol 2014 December, 17(4): 105-109. Published on 20 December 2014.
Background: The pre-storage condition of blood culture bottles prior to entering the automated blood culture system may affect the time to detection (TTD) of microorganisms and the final report days.
Methods: We compared the TTD and final report days according to the pre-incubation conditions after laboratory operating hours: room temperature (RT) vs. a BacT/Alert unit (BioMerieux Inc.) for 3 months respectively. All bottles were inserted into the main BacT/Alert system the next morning.
Results: TTD was significantly reduced by pre-incubating bottles in a BacT/Alert unit (median, 8.4 h) compared to pre-storage at RT (median, 12.4 h) (P＜ 0.001). The final report of bacterial identification and drug susceptibility within 2 days was available for 24.4% of bottles pre-incubated in a BacT/Alert unit compared to 14.9% of those incubated at RT. The false positive results were significantly higher for pre-incubation in a BacT/Alert unit (0.81%) than for that (0.29%) at RT (P＜0.001).
Conclusion: If a clinical microbiology laboratory is not operational for 24 hours, an automated blood culture unit might be a good alternative to reduce TTD and allow the submission of a faster final report compared to pre-storage at RT. However, false positive readings increased more than two-fold by pre-incubation in a BacT/Alert unit.
[in Korean]
Hyunmin Koo, Younghee Seo, Yangsoon Lee, Hyukmin Lee, Dongeun Yong, Seok Hoon Jeong, Kyungwon Lee
Ann Clin Microbiol 2014 December, 17(4): 110-114. Published on 20 December 2014.
Background: Neisseria gonorrhoeae infection remains prevalent, and the emergence of antimicrobial resistance has made the treatment and control of gonorrhea more difficult. Therefore, it is important to compare isolation methods and transport media to overcome gonorrhea via epidemiologic understanding and to determine co-infection rates with other sexually transmitted diseases among primary-care hospitals. In this study, we determine the recovery rate of transferred specimens according to type of transport media and co-infection rate using PCR.
Methods: Genital specimens were collected at three primary-care hospitals from January 2010 to November 2012 using transgrow media and commercial BD transport media. Culture and multiplex PCR were conducted to isolate N. gonorrhoeae.
Results: Among 162 specimens, 57 (35.2%) isolates were recovered, and 146 (90.1%) specimens were positive for multiplex PCR. The recovery rate was 29.9% (78/261) using transgrow media and 19.2% (50/261) using BD transport media. The most common co-infected bacteria with N. gonorrhoeae was Chlamydia trachomatis (15.8%), followed by Mycoplasma hominis (6.2%) and M. genitalium (3.4%).
Conclusion: Under general transport conditions, the rate of recovery of N. gonorrhoeae was as low as 19.2-29.9% depending on the type of transport media, suggesting that molecular diagnostic methods are required to detect the remaining 70% of gonorrhea-infected patients. Co-infection with other sexually transmitted diseases was not rare, and other tests for accurate additional antimicrobial regimens should also be considered.
[in Korean]
Jun Hyung Lee, Bo Hyun Kim, Mi-Kyung Lee
Ann Clin Microbiol 2014 December, 17(4): 115-122. Published on 20 December 2014.
Background: The Anyplex plus MTB/NTM and MDR-TB Detection kits (Seegene, Korea) a real-time PCR assays for direct detection of Mycobacterium tuberculosis (MTB) and nontuberculous mycobacteria (NTM) and for identification of rifampin (RIF) and isoniazid (INH) resistance of MTB in various specimens. We evaluated the diagnostic performance of the Anyplex plus MTB/NTM and MDR-TB Detection kit.
Methods: To determine the ability of the kit to detect MTB and NTM, 557 samples were tested. The diagnostic performance of the Anyplex plus MTB/NTM Detection kit was determined based on the results of culture, nucleic acid amplification tests (NAAT), radiologic analysis, and clinical features suggestive of mycobacterial infection. The performance of the kit was compared with those of other real-time PCR kits. For the drug susceptibility test (DST), 51 MTB isolates were tested. The diagnostic performance of the Anyplex plus MDR-TB Detection kit was determined based on the conventional DST and compared with other molecular DST kits.
Results: Sensitivity and specificity for MTB detection of the Anyplex plus MTB/NTM Detection kit were 82.9% (63/76) and 99.4% (478/481), respectively, while those for NTM detection were 76.5% (13/17) and 89.6% (484/540). Sensitivity and specificity for RIF resistance detection of the Anyplex plus MDR-TB Detection kit were 100% (3/3) and 97.9% (47/48), respectively, while those for INH resistance detection were 83.3% (5/6) and 100% (45/45).
Conclusion: The Anyplex plus MTB/NTM Detection kit showed good diagnostic performance for detection of MTB and NTM. Especially in MTB-positive cases, the Anyplex plus MDR-TB Detection kit provided rapid and reliable results of drug resistance to RIF and INH.
[in Korean]
Sung Kuk Hong, Sue Shin, Jong-Hyun Yoon, Eui-Chong Kim
Ann Clin Microbiol 2014 December, 17(4): 123-127. Published on 20 December 2014.
We report a suspicious case of spontaneous bacterial peritonitis (SBP) caused by Providencia rettgeri and Clostridium perfringens in a patient with alcoholic cirrhosis. The patient presented with altered mentality and was taken to the emergency room. He was diagnosed with SBP after abdominal paracentesis and computed tomography and was treated with ceftriaxone and metronidazole. The pathogens were identified under suspicion of polymicrobial infection because of Gram-staining discrepancies between broth from blood culture bottles and colonies on solid media. He died of septic shock despite transfer to the intensive care unit. Although we could not conclude which organism had the leading role in this case of SBP and septicemia, we did verify the importance of Gram staining in a microbiology laboratory in terms of quality assurance.
Jaehyeon Lee, Yong Gon Cho, Dal Sik Kim, Hye Soo Lee
Ann Clin Microbiol 2014 December, 17(4): 128-131. Published on 20 December 2014.
Eggerthella lenta is rarely isolated from blood but may occur as an opportunistic pathogen with high morbidity and mortality. We report a case of E. lenta bacteremia after an endoscopic retrograde cholangiopancreatography in an end-stage renal disease patient.
Hee Jae Huh, Hyun-Young Kim, Young Eun Ha, Chang-Seok Ki, Nam Yong Lee
Ann Clin Microbiol 2014 December, 17(4): 132-135. Published on 20 December 2014.
Erysipelothrix rhusiopathiae is a Gram-positive bacillus that causes infections primarily in animals. In humans, the bacteria usually cause localized or generalized cutaneous infections. A 75-year-old man with chronic alcoholism presented with abdominal pain. Abdominal computed tomography and laboratory findings suggested an intra-abdominal abscess in the periaortic soft tissue. While no definitive infectious source was identified, E. rhusiopathiae was identified by 16S rRNA-based gene sequencing from culture-negative, periaortic necrotic tissue, subsequent to empiric antibiotic treatment. It is suggested that E. rhusiopathiae has the potential to cause intra-abdominal abscesses. This case report highlights the usefulness of DNA sequencing to identify pathogens in patients pretreated with antibiotics.
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