Da Hae Shim, Hee Jung Kim, Hye Kyung Hong
Ann Clin Microbiol 2016 March, 19(1): 1-6. Published on 20 March 2016.
Background: Microbial screening tests of umbilical cord blood (UCB) are essential for stem cell transplantation. We analyzed the microbial contamination rate and distribution of isolated microorganisms over 10 years of samples from the MEDIPOST Cord Blood Bank. In addition, we studied the influence of inoculum volume microorganism culture and compared the yield and speed of microorganism detection.
Methods: Microbial screening tests were performed using a manual method, which includes using an inoculum of 2 mL of plasma, a byproduct of UCB processing from pediatric culture bottles. When positive blood culture was detected, each set was once again inoculated with 2 mL and 4 mL of plasma.
Results: From 2004 to 2013, a total of 133,610 UCB units were screened, of which 1,311 (0.9%) tested positive for contamination. The most frequently identified microorganism was Escherichia coli (34.6%), followed by Bacillus spp. (12.8%), Enterococcus faecalis (5.3%) and Klebsiella pneumoniae (4.4%). The total yield rate increased by 0.2% over this time period, although the yield rate of Bacillus spp. increased by 8.3%.
Conclusion: The results of this study could be used in many ways with both domestic and international data regarding cord blood contamination. Also, other microbiology laboratories using culture conditions similar to ours could refer this study when preparing guidelines. Finally, by detecting low levels of bacteria, we have contributed to cord blood safety.
[in Korean]
Young Ah Kim, John Hoon Rim, Min Hyuk Choi, Heejung Kim, Kyungwon Lee
Ann Clin Microbiol 2016 March, 19(1): 7-12. Published on 20 March 2016.
Background: Increasing rates of Clostridium difficile infection (CDI) have been reported mainly in Europe and North America; however, only limited reports have originated in Korea. The current epidemiology of CDI in the community could help to understand the outpatient healthcare environment and to extend infection control measures to outpatient settings.
Methods: C. difficile isolates in NHIS Ilsan Hospital from 2012 to 2014 were included in this study. Clinical characteristics, acquisition types, and previous antimicrobial therapy were obtained via Electronic Medical Records. C. difficile culture was performed only in unformed stool. Toxin was positive by enzyme-linked fluorescent immunoassay (ELFA) in 247 specimens. In addition, toxin B and binary toxin gene were detected by PCR in 57 specimens. CDI was defined by toxigenic C. difficile isolation in unformed stool.
Results: In the previous 3 years, 251 unduplicated C. difficile cases have been detected; 168 healthcare facility-associated hospital onset (HCFA-HO), 45 healthcare facility-associated community onset (HCFA-CO), and 38 community-associated (CA). Toxin positive rates by ELFA for toxin A&B were HCFA-HO 50.6% (84/166), HCFA-CO 41.9% (18/43), and CA 42.1% (16/38). Toxin positive rate by PCR for tcdB were HCFA-HO 62.9% (22/35), HCFA-CO 69.2% (9/13), and CA 100% (9/9). No binary toxin (cdtA/cdtB) was detected in 57 cases.
Conclusion: Community-associated CDI may be underestimated in Goyang province, Korea, especially by commonly used ELFA toxin assay. The spread of community-associated CDI should be recognized as an increasing burden of public health.
[in Korean]
Jiyoung Chang, Jin Kyung Yu, Changeun Song, In Yang Park, Yeon-Joon Park
Ann Clin Microbiol 2016 March, 19(1): 13-19. Published on 20 March 2016.
Background: While 7.6% of cultured genital Mycoplasmataceae was identified as Ureaplasma urealyticum, most of them were Ureaplasma parvum (80.3%). This is the first study differentiating between these two species. We investigated the prevalence and antimicrobial resistance of genital Mycoplasmataceae in Korean women.
Methods: A total of 150 specimens submitted to the laboratory for culture of M. hominis and Ureaplasma spp. were included. Detection and antimicrobial susceptibility tests were performed with the Mycoplasma IST2 kit (bioMérieux, France). The identification of Ureaplasma spp. was performed by PCR, and mutations in drug resistance genes were investigated by PCR and sequencing.
Results: In total, 66 specimens (44.0%) were positive for genital Mycoplasmatacea: U. parvum, 53 (80.3%); U. urealyticum, 5 (7.6%); M. hominis, 2 (3.0%); mixed infection, 6 (9.1%). Susceptibilities of Ureaplasma spp. to erythromycin, azithromycin, clarithromycin, and doxycycline were 86.0%, 80.7%, 98.2%, and 94.7%, respectively. The susceptibility of Ureaplasma spp. to ofloxacin and ciprofloxacin was 47.4% and 17.5%, respectively. The S83L mutation was found in the ParC subunit of the ofloxacin-resistant (5/7, 71.4%) and the ciprofloxacin-resistant isolates (7/14, 50.0%). One M. hominis isolate showed resistance to erythromycin, azithromycin, and clarithromycin but susceptibility to josamycin, pristinamycin, fluoroquinolones, and tetracyclines.
Conclusion: The prevalence of genital Mycoplasmataceae in Korean women was 44.0%; most of them were identified as U. parvum. As more than 10% of Ureaplasma spp. showed non-susceptibility to erythromycin and azithromycin (15.5%, 20.7%), a susceptibility test is needed prior to use of these antibiotics. Further study is needed about the clinical features of infections caused by U. urealyticum vs. U. parvum and their associated resistance mechanisms.
[in Korean]
Tae Sang Oh, Hee Yoon Kang, You Sun Nam, Young Jin Kim, Eun Kyung You, Min Young Lee, Sun Young Cho, Hee Joo Lee
Ann Clin Microbiol 2016 March, 19(1): 20-23. Published on 20 March 2016.
In the RNA-based study, it is important to extract high-quality RNA. However, RNA extraction from Mycobacterium tuberculosis is problematic due to its thick, waxy cell wall rich in mycolic acid, which renders the cells resistant to lysis. Using TRIzol reagent and several powerful bead-beating steps, a high quantity of RNA was obtained.
Su-Jin Chae, Young-Sun Yun, Cheon-Kwon Yoo, Gyung Tae Chung, Deog-Yong Lee
Ann Clin Microbiol 2016 March, 19(1): 24-27. Published on 20 March 2016.
Salmonellosis is a common food- and water-borne disease and is also a major zoonosis. Currently, the isolation of rare Salmonella serotypes is increasing every year in Korea. Among them, the Salmonella serotype Tilene was first isolated from two people who visited a hospital located in Andong-si in 2013. Clinical symptoms were weak or non-existent. There was no clear epidemiological connection between the two cases. However, it was assumed that both were independently exposed to a single infectious agent. Perhaps due to their geographical proximity, molecular epidemiological analysis showed the same result between the isolated strains. This serotype has increasingly reported an association with hedgehogs. Recently, the importation of exotic animals, including hedgehogs, as pets has been gradually increasing. Thus, it is recommended that high-risk groups avoid contact with exotic pets.
Sholhui Park, Hae-Sun Chung, Eui Kyo Seo, Yeung Chul Mun, Miae Lee
Ann Clin Microbiol 2016 March, 19(1): 28-31. Published on 20 March 2016.
Corynebacterium striatum is a commonly isolated contaminant in the clinical microbiology. However, it can be an opportunistic pathogen in immunocompromised and even immunocompetent hosts. The increasing prevalence of C. striatum infection has been associated with immunosuppression and prosthetic devices. We report a case of meningitis with cerebrospinal fluid drainage and a case of catheter-related bloodstream infection caused by C. striatum. The isolates were identified as nondiphtherial Corynebacterium species by VITEK 2 (bioMérieux, France) anaerobe and Corynebacterium card. The final identification by 16S rRNA gene sequencing analysis was C. striatum with 99.7% identity and 99.6% identity with C. striatum ATCC 6940, respectively. Both strains were sensitive to vancomycin and gentamicin, but multidrug-resistant to ciprofloxacin, penicillin, erythromycin and imipenem.
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