Guidelines for Laboratory Diagnosis of Coronavirus Disease 2019 (COVID-19) in Korea.

The outbreak of coronavirus disease 2019 (COVID-19), which began in December 2019, is still ongoing in Korea, with >9,000 confirmed cases as of March 25, 2020. COVID-19 is a severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infection, and real-time reverse transcription-PCR is currently the most reliable diagnostic method for COVID-19 around the world. Korean Society for Laboratory Medicine and the Korea Centers for Disease Prevention and Control propose guidelines for diagnosing COVID-19 in clinical laboratories in Korea. These guidelines are based on other related domestic and international guidelines, as well as expert opinions and include the selection of test subjects, selection of specimens, diagnostic methods, interpretation of test results, and biosafety.

Identification of novel candidate target genes, including EPHB3, MASP1 and SST at 3q26.2-q29 in squamous cell carcinoma of the lung.

BACKGROUND: The underlying genetic alterations for squamous cell carcinoma (SCC) and adenocarcinoma (AC) carcinogenesis are largely unknown. METHODS: High-resolution array- CGH was performed to identify the differences in the patterns of genomic imbalances between SCC and AC of non-small cell lung cancer (NSCLC). RESULTS: On a genome-wide profile, SCCs showed higher frequency of gains than ACs (p = 0.067). More specifically, statistically significant differences were observed across the histologic subtypes for gains at 2q14.2, 3q26.2-q29, 12p13.2-p13.33, and 19p13.3, as well as losses at 3p26.2-p26.3, 16p13.11, and 17p11.2 in SCC, and gains at 7q22.1 and losses at 15q22.2-q25.2 occurred in AC (P < 0.05). The most striking difference between SCC and AC was gains at the 3q26.2-q29, occurring in 86% (19/22) of SCCs, but in only 21% (3/14) of ACs. Many significant genes at the 3q26.2-q29 regions previously linked to a specific histology, such as EVI1,MDS1, PIK3CA and TP73L, were observed in SCC (P < 0.05). In addition, we identified the following possible target genes (> 30% of patients) at 3q26.2-q29: LOC389174 (3q26.2),KCNMB3 (3q26.32),EPHB3 (3q27.1), MASP1 and SST (3q27.3), LPP and FGF12 (3q28), and OPA1,KIAA022,LOC220729, LOC440996,LOC440997, and LOC440998 (3q29), all of which were significantly targeted in SCC (P < 0.05). Among these same genes, high-level amplifications were detected for the gene, EPHB3, at 3q27.1, and MASP1 and SST, at 3q27.3 (18, 18, and 14%, respectively). Quantitative real time PCR demonstrated array CGH detected potential candidate genes that were over expressed in SCCs. CONCLUSION: Using whole-genome array CGH, we have successfully identified significant differences and unique information of chromosomal signatures prevalent between the SCC and AC subtypes of NSCLC. The newly identified candidate target genes may prove to be highly attractive candidate molecular markers for the classification of NSCLC histologic subtypes, and could potentially contribute to the pathogenesis of the squamous cell carcinoma of the lung.

Gain at chromosomal region 5p15.33, containing TERT, is the most frequent genetic event in early stages of non-small cell lung cancer.

Chromosomal imbalances resulting in altered gene dosage play a role in the molecular pathogenesis of non-small cell lung cancer (NSCLC), but the target genes remain to be identified. To identify early-stage genetic events that drive progression of NSCLC, we conducted a high-resolution array comparative genomic hybridization (CGH) study, using an array of 4,046 bacterial artificial chromosome clones to screen for DNA copy number changes associated with individual genes in 36 tumors obtained from patients in early stages of NSCLC. Multiple early genetic events occurring on chromosome 5p were identified, with a minimal detection region at 5p15.33 approximately 12. The most frequent finding involved gain of 5p15.33, observed in 15 of 19 stage I (A+B) cancers (79%) and in 28 of the total 36 NSCLC cases (78%). This locus harbors the genes TERT, SLC6A19, and SLC6A18 and is a telomeric boundary at bacterial artificial chromosome (BAC) clone 91_J20. Other potential candidate genes evidencing high numbers of genomic copy number changes (> or =40% of patients) included the following genes, encountered in >50% of 19 stage I (A+B) cancers: CEP72 and TPPP (14 of 19; 74%); AHRR, EXOC3 (previously SEC6L1), SLC9A3, LOC442126, ZDHHC11, BRD9, and TRIP13 (13/19; 68%); and CLPTM1L (alias CRR9), SLC6A3 (previously DAT1), and LOC401169 (10/19; 53%). Fluorescence in situ hybridization validated the array CGH findings. The gain of 5p15.33 is thus one of the most consistent alterations in the early stages of lung cancer, and a series of genes in the critical 5p15.33 region may be used as novel biomarkers for the early detection and classification of lung cancer.

Association between Biofilm Formation and Antimicrobial Resistance in Carbapenem-Resistant Pseudomonas Aeruginosa.

Recently, carbapenem resistance in P. aeruginosa is an increasingly important problem globally. Biofilm formation is a well-known pathogenic mechanism of P. aeruginosa, and the gene, pslA, plays an important role in its primary stages. We studied the association between biofilm formation and pslA in carbapenem-resistant P. aeruginosa isolates, along with antimicrobial resistance and the prevalence of metallo-ß-lactamase (MBL) genes, based on the presence of pslA 82 carbapenem-resistant P. aeruginosa isolates were collected from a tertiary hospital in Daejeon, Korea, between March 2008 and June 2014. Minimum inhibitory concentrations (MICs) of nine antimicrobial agents were determined using the agar dilution method. Biofilm formation was measured by microtiter plate assay. PCR and sequencing were used to identify pslA and the MBL gene. 76 (92.7%) carbapenem-resistant isolates were biofilm producers. These biofilm producers showed higher levels of amikacin, ceftazidime, and cefepime resistance than non-producers. pslA was detected in 71 (93.4%) biofilm-producing isolates and these results were statically significant (p<0.01). 11 isolates carrying pslA and blaIMP-6 were extremely resistant to all antimicrobials tested. In this study, biofilm formation was significantly associated with pslA Furthermore, the coexistence of pslA and the MBL gene in carbapenem-resistant isolates likely contributed to the increase in antimicrobial resistance.

The 99th percentile values of six cardiac troponin assays established for a reference population using strict selection criteria.

BACKGROUND: Since the 99th percentile reference limit for cardiac troponin (Tn) can vary depending on the reference population, Sandoval et al. published systematic selection criteria. In this study, these systematic criteria were applied for the first time to obtain the 99th percentile reference limits for 6 Tn tests. METHODS: The reference population was selected in accordance with the systematic criteria, and reference limits were set with respect to the six types of Tn assays. The coefficient of variation (CV) at the reference limit was determined using 3-4 concentrations of frozen serum. RESULTS: In total, 641 South Koreans (303 males, 338 females) were selected as the reference population. The 99th percentile reference limit of Tn in the six assays ranged from 13.4 to 34.2pg/ml. The measurable fractions among the reference population ranged from 1.3% to 80.5%. The CVs at the reference limit ranged from 5.3% to 43.0%, and three were <10%. CONCLUSIONS: In this study, a reference population was selected for the first time in accordance with the systematic criteria of Sandoval et al., and the reference limit for South Koreans was established. The values obtained in this study are different from those proposed by manufacturers, which confirms the importance of having a reference population. Four out of six assays did not fulfill the criteria for high-sensitivity tests.

Multitarget fluorescence in situ hybridization and melanoma antigen genes analysis in primary bladder carcinoma.

Conventional urine cytology has a poor prognostic performance for detecting bladder cancer, particularly for low-grade tumors. Fluorescence in situ hybridization (FISH) for chromosomes altered in bladder cancer and testing for antigens selectively expressed in tumors are promising alternatives. This study investigated the use of FISH for detecting aneuploidy of chromosomes 3, 7, 17, and 9p21 and reverse transcriptase PCR (RT-PCR) for the expression of melanoma associated antigen (MAGE) genes for the diagnosis of bladder cancer in voided urine specimens. The two techniques were compared with cystoscopic bladder biopsy results in 47 patients with urothelial cancer and 15 patients with benign prostatic hyperplasia. FISH detected cancer in 42 of 47 patients (89.4%). This was significantly higher than the detection rate 30 of 47 patients (64.3%) by MAGE RT-PCR (P < 0.001). The sensitivity of FISH increased with histologic grade and stage of the tumors, correctly identifying 77.8% of pTa and pTis, 94.1% of pT1, and 100% of Pt2-4 tumors. MAGE, however, showed a decreased sensitivity in high grade advanced tumors; it was positive in 66.7% of pTa and pTis, 70.6% of pT1, and 50% of Pt2-4 tumors. Together, the tests correctly identified urothelial cancer in 46 of 47 patients (97.9%). Combined FISH and MAGE RT-PCR testing may offer a promising alternative to conventional urine cytology in screening high-risk populations and in monitoring bladder cancer patients for recurrent tumor.

Characteristics of the Molecular Epidemiology of CTX-M-Producing Escherichia coli Isolated from a Tertiary Hospital in Daejeon, Korea.

The aims of this study were to characterize the molecular epidemiological profiles of CTX-M-producing uropathogenic Escherichia coli isolates from a tertiary hospital in Daejeon, Korea, and to investigate the genetic diversity and compare the prevalence of sequence types (STs) in different areas. Extended spectrum ß-lactamase-producing E. coli strains isolated from urine were analyzed for CTX-M, integrons, and insertion sequence common regions (ISCRs) by PCR and sequencing. Multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), phylogenetic analysis, and rep-PCR were also used for molecular typing of the isolates. Of 80 CTX-M producers, 31 and 46 expressed CTX-M-15 and CTX-M-14, respectively. MLST analysis indicated that the most prevalent ST was ST131 (n = 34, 42.5%), followed by ST38 (n = 22, 27.5%), ST405 (n = 8, 10.0%), and ST69 (n = 6, 7.5%). Most CTX-M producers harbored class 1 integrons. ST131 strains belonged to phylogenetic group B2 and showed identical rep-PCR patterns, whereas ST69, ST38, and ST405 strains belonged to phylogenetic group D; the ST38 and ST405 strains displayed the same rep-PCR pattern, respectively. ST131 and ST38 isolates showed 21 and 19 distinct types, respectively, by PFGE. In Daejeon, D-ST38 CTX-M-14 producers were relatively more prevalent than in other countries and Korean cities. Our results indicate that CTX-M-producing E. coli isolates belonged mostly to ST131 or ST38 and were more related to hospital-onset than to community-onset infections and that the blaCTX-M gene may vary according to the ST.

Prognostic implications for gastric carcinoma based on loss of heterozygosity genotypes correlation with clinicopathologic variables.

In this study we used polymorphic DNA markers to examine 38 patients with gastric carcinoma for loss of heterozygosity (LOH) on five chromosomal arms. The aims were to compare LOH genotyping with the clinicopathologic variables and to identify some genetic differences between early (EGC) and advanced gastric carcinoma (AGC). The frequency of LOH was found in 27 of 38 (71.1%) cases with a low-level LOH in 17 (44.7%) and a high-level LOH (LOH-H) in 10 (26.3%). There was statistical significance found in the differentiation of cells (WD/MD vs. PD [well or moderately differentiated vs. poorly differentiated]), metastasis (absent vs. present), and tumor-node-metastasis stage (I/II vs. III/IV) based on LOH genotyping. The frequency of LOH in the markers of chromosome 6 revealed a significant difference between the early and advanced stages (P=0.043). However, there were no differences in each chromosome or in the number of affected chromosomes with an allelic loss between the histologic types EGC and AGC, except for the frequency of the markers on chromosome 22. These findings suggest that LOH genotyping may be another independent prognostic indicator in gastric carcinoma, that LOH-H, particularly the LOH on chromosome 6, could be associated with an unfavorable prognosis, while the LOH on chromosome 22 may be related to the histologic progression of gastric carcinoma.

Microsatellite alterations in hepatocellular carcinoma and intrahepatic cholangiocarcinoma.

A series of 20 hepatocellular carcinomas and 8 intrahepatic cholangiocarcinomas was screened from the Korean population for microsatellite alterations, including a loss of heterozygosity and replication errors using nine microsatellite markers containing several genes. The microsatellite results and our previous comparative genomic hybridization results of two tumors were compared at each locus, and the correlations between these and clinicopathologic variables were examined. The most characteristic findings were found at 13q. Replication errors were prevalent at D13S160 (13q21.2 approximately q31) and D13S292(13q12). The incidence of loss of heterozygosity, however, was higher at D13S153 (13q14.1 approximately q14.3) and D13S265(13q31 approximately q32). In contrast, there were higher deletion frequencies observed in hepatocellular carcinoma (HCC) and higher amplification frequencies observed in intrahepatic cholangiocarcinoma at 13q in our previous comparative genomic hybridization (CGH) study. Higher frequencies of replication errors were observed at D16S408 (13q12 approximately q21) and D16S504(13q23 approximately q24) in the HCC. This study found that significant differences in the patterns of genetic instability of microsatellites were dependent on the chromosomal loci. It is believed that certain genes at altered CGH regions, which are relevant to the development and/or progression of these cancers, are activated by different mutation mechanisms.

Correlation between virulence genotype and fluoroquinolone resistance in carbapenem-resistant Pseudomonas aeruginosa.

BACKGROUND: Pseudomonas aeruginosa is a clinically important pathogen that causes opportunistic infections and nosocomial outbreaks. Recently, the type III secretion system (TTSS) has been shown to play an important role in the virulence of P. aeruginosa. ExoU, in particular, has the greatest impact on disease severity. We examined the relationship among the TTSS effector genotype (exoS and exoU), fluoroquinolone resistance, and target site mutations in 66 carbapenem-resistant P. aeruginosa strains. METHODS: Sixty-six carbapenem-resistant P. aeruginosa strains were collected from patients in a university hospital in Daejeon, Korea, from January 2008 to May 2012. Minimum inhibitory concentrations (MICs) of fluoroquinolones (ciprofloxacin and levofloxacin) were determined by using the agar dilution method. We used PCR and sequencing to determine the TTSS effector genotype and quinolone resistance-determining regions (QRDRs) of the respective target genes gyrA, gyrB, parC, and parE. RESULTS: A higher proportion of exoU+ strains were fluoroquinolone-resistant than exoS+ strains (93.2%, 41/44 vs. 45.0%, 9/20; P≤0.0001). Additionally, exoU+ strains were more likely to carry combined mutations than exoS+ strains (97.6%, 40/41 vs. 70%, 7/10; P=0.021), and MIC increased as the number of active mutations increased. CONCLUSIONS: The recent overuse of fluoroquinolone has led to both increased resistance and enhanced virulence of carbapenem-resistant P. aeruginosa. These data indicate a specific relationship among exoU genotype, fluoroquinolone resistance, and resistance-conferring mutations.

Epidemiological characterizations of class 1 integrons from multidrug-resistant acinetobacter isolates in Daejeon, Korea.

BACKGROUND: Multidrug-resistant (MDR) Acinetobacter spp. acquire antimicrobial agent-resistance genes via class 1 integrons. In this study, integrons were characterized to investigate the antimicrobial resistance mechanisms of MDR Acinetobacter isolates. In addition, the relationship between the integron type and integron-harboring bacterial species was analyzed by using epidemiological typing methods. METHODS: Fifty-six MDR Acinetobacter spp.-A. baumannii (N=30), A. bereziniae (N=4), A. nosocomialis (N=5), and A. pittii (N=17)-were isolated. The minimum inhibitory concentrations (MICs) were determined on the basis of the results of the Epsilometer test (Etest). PCR and DNA sequencing was performed to characterize the gene cassette arrays of class 1 integrons. Multilocus sequence typing (MLST) and repetitive extragenic palindromic sequence (REP)-PCR were performed for epidemiological typing. RESULTS: Class 1 integrons were detected in 50 (89.3%) of the 56 isolates, but no class 2 or 3 integron was found within the cohorts. The class 1 integrons were classified into 4 types: 2.3-kb type A (aacA4-catB8-aadA1), 3.0-kb type B (aacA4-blaI MP-1 -bla OXA-2), 3.0-kb type C (bla VIM-2-aacA7-aadA1), and 1.8-kb type D (aac3-1-bla OXA-2 -orfD). Type A was most prevalent and was detected only in A. baumannii isolates, except for one A. bereziniae isolate; however, type B was amplified in all Acinetobacter isolates except for A. baumannii isolates, regardless of clone and separation time of the bacteria. CONCLUSIONS: Although class 1 integron can be transferred horizontally between unrelated isolates belonging to different species, certain types of class 1 integrons tend to transfer horizontally and vertically among A. baumannii or non-baumannii Acinetobacter isolates.

Characterization of CTX-M-14- and CTX-M-15-Producing Escherichia coli and Klebsiella pneumoniae Isolates from Urine Specimens in a Tertiary-Care Hospital.

This study aimed to characterize CTX-M producers of urinary E. coli and K. pneumoniae isolates and to determine the prevalence of plasmid-mediated antimicrobial resistance genes among them. Minimum inhibitory concentrations (MICs) were determined, and PCR and sequencing were performed. Among the 42 (82.3%) E. coli and 24 (77.4%) K. pneumoniae isolates containing bla(CTX-M), bla(CTX-M-14) and bla(CTX-M-15) were detected in 23 and 19 E. coli isolates, respectively, and in 7 and 17 K. pneumoniae isolates, respectively. CTX-M producers of urinary E. coli and K. pneumoniae were resistant to multiple antibiotics and contained other antimicrobial resistance genes. CTX-M-15 producers contained more antimicrobial resistance genes than did CTX-M-14 producers.

Nosocomial infection by sequence type 357 multidrug-resistant Acinetobacter baumannii isolates in a neonatal intensive care unit in Daejeon, Korea.

Acinetobacter baumannii is an important microorganism responsible for a number of nosocomial outbreaks, in particular, in intensive care units (ICUs). We investigated a nosocomial infection caused by multidrug-resistant (MDR) A. baumannii in a neonatal intensive care unit (NICU) in Korea. A. baumannii isolates were characterized using Etest (AB Biodisk, Sweden), two multiplex PCR assays, and multilocus sequence typing (MLST) scheme. PCR and PCR mapping experiments were performed for detecting and characterizing the determinants of antimicrobial resistance. Eight strains isolated from an NICU belonged to European (EU) clone II and revealed only one sequence type (ST), namely, ST357. All the isolates were susceptible to imipenem but were resistant to amikacin, gentamicin, ceftazidime, cefepime, and ciprofloxacin. To the best of our knowledge, this is the first report of a nosocomial infection in an NICU in Korea caused by ST357 MDR/carbapenem-susceptible A. baumannii strains. This result demonstrates that nosocomial outbreaks of MDR/carbapenem-susceptible strains as well as MDR/carbapenem-resistant isolates may occur in NICUs.

Spread and genetic characterization of ST137 and ST138 multidrug-resistant Acinetobacter baumannii isolated from a tertiary hospital in Korea.

Acinetobacter baumannii is an increasingly important global nosocomial pathogen. Clonal complex 92 (CC92) has become the most prevalent clonal complex in many regions. We investigated the molecular epidemiology and resistance profile of 52 imipenem-nonsusceptible A. baumannii isolates obtained from a university hospital in Daejeon, Korea, from 2007 to 2011. The minimum inhibitory concentrations of 7 antimicrobials were determined. PCR and DNA sequencing were used to identify genes contributing to resistance phenotypes. Multilocus sequence typing was performed to determine epidemiological relationships, and European clonal lineages were identified by multiplex PCR. The A. baumannii isolates were of 6 sequence types (STs; ST92, ST75, ST137, ST138, ST358, and ST69) and 1 allelic profile. All 6 STs were clustered into CC92 and the European clone II. ST138 was the most commonly observed ST, followed by ST137. We identified several genetic characteristics in carbapenem-, aminoglycoside-, and fluoroquinolone-resistance genes between ST137 and ST138. Imipenem-nonsusceptible A. baumannii has emerged in Daejeon, Korea, over a 5-year period, and is associated with the global spread of CC92 and European clone II. Epidemiological surveillance may be required to track the spread of epidemic strains and to guide adequate containment measures.

Prevalence and genetic analysis of multidrug-resistant Pseudomonas aeruginosa ST235 isolated from a hospital in Korea, 2008-2012.

Pseudomonas aeruginosa is one of the primary opportunistic pathogens responsible for nosocomial infections. Recently, sequence type 235 (ST235) has been found internationally in a multidrug-resistant clone and is involved in the dissemination of genes encoding IMP-6 and VIM-2. This study aimed to describe the prevalence of metallo-ß-lactamase (MBL), epidemiological relationship, and genetic characterization to aminoglycoside resistance in carbapenem-resistant P. aeruginosa isolates obtained from a tertiary hospital in Daejeon, Korea, from 2008 to 2012. Minimum inhibitory concentrations (MICs) of six antimicrobial agents were determined using the agar dilution method. PCR and DNA sequencing were used to identify MBL genes, class 1 integrons, and genes contributing to the aminoglycoside resistance phenotype. In addition, an epidemiological relationship was investigated by multilocus sequence typing (MLST). Eleven (16.2%) carbapenem-resistant isolates were MBL-producers; the major MBL type was IMP-6 (10 isolates). IMP-6-producing isolates were multidrug-resistant and belonged to ST235. All IMP-6-producing isolates had class 1 integrons (5.5 Kb; blaIMP-6-qac-aacA4-blaOXA-1-addA1). We identified genetic characteristics in aminoglycoside genes between ST235 and non-ST235. All ST235 isolates contained aminoglycoside-modifying enzyme (AME) genes, whereas 23.5% of non-ST235 isolates contained AME genes. Development and spread of the aminoglycoside resistance gene in P. aeruginosa non-ST235 could result in multidrug resistance in the future.

AbaR7, a genomic resistance island found in multidrug-resistant Acinetobacter baumannii isolates in Daejeon, Korea.

BACKGROUND: Acinetobacter baumannii resistance islands (AbaRs) have been recently recognized as mobile genetic elements that harbor multiple resistance determinants and are associated with multidrug resistance (MDR). In the present study, we aimed to determine the AbaRs conferring multiple antimicrobial resistance and their clonal relatedness to MDR A. baumannii clinical isolates obtained from a university hospital in Daejeon, Korea. METHODS: This study included 29 MDR A. baumannii strains isolated in Daejeon, Korea. The minimal inhibitory concentrations (MICs) were determined by Etest. A. baumannii isolates were characterized using the 2 multiplex PCR assays and multilocus sequence typing (MLST) scheme. To detect and characterize AbaRs, PCR and PCR mapping experiments were performed. RESULTS: Twenty-seven of the 29 isolates belonged to the European (EU) clone II lineage and contained 5 sequence types (STs) (75, 92, 137, 138, and 357). In this study, ST357 was confirmed for the first time in Korea. Only 2 of the 29 isolates belonged to the EU clone I lineage, and were confirmed as ST109. These 2 isolates harbored the 22-kb AbaR7 aacC1-orfP-orfQ-aadA1 gene cassette array. In contrast, AbaR was not found in EU clone II isolates. CONCLUSIONS: This is the first study that attempted to determine the AbaRs in MDR A. baumannii isolates in Korea. We found 2 EU clone I isolates (ST109) that harbored AbaR7.

Expression of Sme efflux pumps and multilocus sequence typing in clinical isolates of Stenotrophomonas maltophilia.

BACKGROUND: Stenotrophomonas maltophilia has emerged as an important opportunistic pathogen, which causes infections that are often difficult to manage because of the inherent resistance of the pathogen to a variety of antimicrobial agents. In this study, we analyzed the expressions of smeABC and smeDEF and their correlation with antimicrobial susceptibility. We also evaluated the genetic relatedness and epidemiological links among 33 isolates of S. maltophilia. METHODS: In total, 33 S. maltophilia strains were isolated from patients in a tertiary hospital in Daejeon. Minimum inhibitory concentrations (MICs) of 11 antimicrobial agents were determined by using agar dilution method and E-test (BioMérieux, France). Real-time PCR analysis was performed to evaluate the expression of the Sme efflux systems in the S. maltophilia isolates. Additionally, an epidemiological investigation was performed using multilocus sequence typing (MLST) assays. RESULTS: The findings of susceptibility testing showed that the majority of the S. maltophilia isolates were resistant to ß-lactams and aminoglycosides. Twenty-one clinical isolates overexpressed smeABC and showed high resistance to ciprofloxacin. Moreover, a high degree of genetic diversity was observed among the S. maltophilia isolates; 3 sequence types (STs) and 23 allelic profiles were observed. CONCLUSIONS: The smeABC efflux pump was associated with multidrug resistance in clinical isolates of S. maltophilia. In particular, smeABC efflux pumps appear to perform an important role in ciprofloxacin resistance of S. maltophilia. The MLST scheme for S. maltophilia represents a discriminatory typing method with stable markers and is appropriate for studying population structures.

Evaluation of the Seeplex® Meningitis ACE Detection kit for the detection of 12 common bacterial and viral pathogens of acute meningitis.

BACKGROUND: Bacterial meningitis is an infectious disease with high rates of mortality and high frequency of severe sequelae. Early identification of causative bacterial and viral pathogens is important for prompt and proper treatment of meningitis and for prevention of life-threatening clinical outcomes. In the present study, we evaluated the value of the Seeplex Meningitis ACE Detection kit (Seegene Inc., Korea), a newly developed multiplex PCR kit employing dual priming oligonucleotide methods, for diagnosing acute meningitis. METHODS: Analytical sensitivity of the kit was studied using reference strains for each pathogen targeted by the kit, while it's analytical specificity was studied using the human genome DNA and 58 clinically well-identified reference strains. For clinical validation experiment, we used 27 control cerebrospinal fluid (CSF) samples and 78 clinical CSF samples collected from patients at the time of diagnosis of acute meningitis. RESULTS: The lower detection limits ranged from 10(1) copies/µL to 5×10(1) copies/µL for the 12 viral and bacterial pathogens targeted. No cross-reaction was observed. In the validation study, high detection rate of 56.4% was obtained. None of the control samples tested positive, i.e., false-positive results were absent. CONCLUSIONS: The Seeplex Meningitis ACE Detection kit showed high sensitivity, specificity, and detection rate for the identification of pathogens in clinical CSF samples. This kit may be useful for rapid identification of important acute meningitis-causing pathogens.