Si Hyun Kim, Eun Hee Park, In Yeong Hwang, Hyukmin Lee, Sae Am Song, Miae Lee, Seungok Lee, Soo Young Kim, Jin Ju Kim, Jong Hee Shin, Seong Geun Hong, Kyeong Seob Shin, Sunjoo Kim, Nam Hee Ryoo, Woonhyoung Lee, Sook Jin Jan4, Jeong Hwan Shin
Ann Clin Microbiol 2019 September, 22(3): 55-60. Published on 20 September 2019.
Background: Salmonella is an important pathogen that causes gastroenteritis and sepsis in humans. Recently, changes in serotype prevalence and an increase in antimicrobial resistance have been reported. This study investigated the distribution of Salmonella serotypes and determined the antimicrobial susceptibility of various strains.
Methods: We collected 113 Salmonella isolates other than Salmonella serotype Typhi from 18 university hospitals in 2015. The serotypes were identified by Salmonella antisera O and H according to the Kauffman White scheme. Antimicrobial susceptibility tests for 12 antibiotics were performed using the disk diffusion method or E-test.
Results: We identified 22 serotypes. Serotype group B (44.2%) was the most common, followed by groups C (34.5%) and D (21.2%). Salmonella I 4,[5],12:i:-(23.0%), S. Enteritidis (16.8%), and S. Typhimurium (12.4%) were the most common species. Resistance rates for ampicillin, chloramphenicol, ceftriaxone, and trimethoprim/sulfamethoxazole were 46.9%, 18.5%, 8.8%, and 5.3%, respectively. The intermediate resistance rate to ciprofloxacin was 29.2%. Six isolates were extended-spectrum β-lactamase (ESBL) producers, including 5 blaCTX-M-15 and 1 blaCTX-M-55.
Conclusion: There have been changes in the serotype prevalence and antimicrobial resistance of Salmonella in Korea, with a high prevalence of CTX-M 15-positive strains. Continuous monitoring of Salmonella serotypes and antimicrobial resistance is warranted.
[in Korean]
Da Young Kang, Jun Sung Hong, Byeol Yi Park, In-Ho Jang, Dokyun Kim, Hyukmin Lee, Seok Hoon Jeong
Ann Clin Microbiol 2019 September, 22(3): 61-70. Published on 20 September 2019.
Background: Antimicrobial resistant continues to pose a threat to public health. Therefore, rapid and accurate antimicrobial susceptibility testing is very important. The objectives of this study were to evaluate the performance of the MicroScan system (Beckman Coulter, USA) with newly developed Korean Antimicrobial Susceptibility Testing Panels (KSCM panels) for antimicrobial susceptibility testing (AST) against clinical isolates in South Korea.
Methods: Three KSCM panels were designed in this study. For the performance evaluation, a total of 1,325 clinical isolates including 1,027 of Gram-negative bacilli and 298 Gram-positive cocci collected from eight general hospitals in South Korea were used. The results by KSCM panels were compared with those by conventional methods.
Results: By KSCM-1 panel for Gram-positive cocci, the rates of categorical agreement (CA) were ＞90% in all the antimicrobials tested in this study. The rates of major error (ME) were also ＜3%, and only three very major error (VME) were identified; each of ampicillin, tetracycline, and quinupristin-dalfopristin in enterococcal isolates. By KSCM-2 panel for Enterobacteriaceae, the rates of CA were also above 90%, and those of ME and VME were less than 3% and 1.5%, respectively. KSCM-3 panels for glucose-non-fermenting Gram-negative bacilli, also showed good agreement rates, i.e., CA rates ＞90%, ME rates ＜3%, and VME rates ＜1.5%.
Conclusion: The newly developed three KSCM panels for MicroScan system (Beckman Coulter) showed excellent performance in AST against a large number of clinical isolates, and they are applicable to clinical microbiology laboratories. (Ann Clin Microbiol 2019;22:61-70)
[in Korean]
Young Sun Joo, Na Eun Kwak, Gun Han Kim, Eun-Jeong Yoon, Seok Hoon Jeong
Ann Clin Microbiol 2019 September, 22(3): 71-76. Published on 20 September 2019.
Background: Pulmonary infection with nontuberculous mycobacteria (NTM) is increasing in South Korea. Since treatment strategy differs by NTM species, accurate identification is necessary. In this study, using Mycobacterium pulmonary isolates recently recovered from a general hospital in Seoul, the prevalence of NTM isolates was investigated.
Methods: A total of 483 Mycobacterium pulmonary strains isolated between May and November 2018 from an 814-bed general hospital in South Korea were analyzed. Bacterial species were identified based on nucleotide sequences of the 16S-23S rDNA internal transcribed spacer and the rpoB gene.
Results: From a total of 1,209 pulmonary specimens from patients suspected to be infected with mycobacteria, 324 deduplicate strains were isolated, comprising 90 Mycobacterium tuberculosis and 229 NTM strains. Among the NTM isolates, 61.5% (n=144) were Mycobacterium avium complex (MAC), including 92 M. avium and 52 Mycobacterium intracellulare, while 8.1% (n=19) represented Mycobacterium abscessus, including 10 M. abscessus subsp. abscessus and 9 M. abscessus subsp. massiliense. In addition, 12 (5.1%) Mycobacterium lentiflavum, 12 (5.1%) Mycobacterium gordonae, 6 (2.6%) Mycobacterium kansasii, and 5 (2.1%) Mycobacterium fortuitum were identified. In addition, Mycobacterium mucogenicum (n=2), Mycobacterium septicum (n=1), Mycobacterium colombiens (n=1), Mycobacterium asiaticum (n=1), and Mycobacterium celatum (n=1) were identified.
Conclusion: Among the recently recovered Mycobacterium pulmonary strains, more than half were identified as NTM, and MAC was the most prevalent NTM, followed by M. abcessuss. (Ann Clin Microbiol 2019;22:71-76)
[in Korean]
Hyein Kang, Namhee Ryoo
Ann Clin Microbiol 2019 September, 22(3): 77-79. Published on 20 September 2019.
Staphylococcus pettenkoferi is a coagulase-negative staphylococci (CoNS) of growing concern. As CoNS could be an important cause of infections in hospitalized patients, especially in immunocompromised patients, accurate identification is critical to timely and effective treatment. In the past, S. pettenkoferi was not identifed by conventional methods or was misidentified as another Staphylococcus species or another genus. To the best of our knowledge, this is the first case of S. pettenkoferi identified using Vitek MS (bioMérieux, France). Two patients admitted to our hospital were confirmed to have bacteremia caused by S. pettenkoferi, which was identified in blood cultures using Vitek MS (bioMérieux). Therefore, we recommend using the Vitek MS (bioMérieux) for rapid and accurate identification of the pathogen causing bloodstream infection when CoNS is suspected. (Ann Clin Microbiol 2019;22:77-79)
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