Microsatellite Typing and Resistance Mechanism Analysis of Voriconazole-Resistant Aspergillus flavus Isolates in South Korean Hospitals.

A recent surveillance study in South Korea revealed that 14% (7/50) of Aspergillus flavus clinical isolates had a voriconazole minimum inhibitory concentration of ≥4 µg/ml. Of seven non-wild-type (non-WT) isolates, six ear isolates from four hospitals shared the same microsatellite genotype. None of the non-WT isolates showed cyp51 mutations associated with azole resistance. However, the mean expression levels of efflux pump (MDR2, atrF, and mfs1) and target (cyp51A) genes exhibited significant differences between non-WT and other isolates.

Lazertinib as a frontline treatment in patients with EGFR-mutated advanced non-small cell lung cancer: Long-term follow-up results from LASER201.

OBJECTIVE: This analysis of the first-line cohort of LASER201 study evaluated the efficacy and safety of lazertinib 240 mg as a frontline therapy for epidermal growth factor receptor (EGFR)-mutated locally advanced or metastatic non-small cell lung cancer (NSCLC). METHODS: A total of 43 patients, with EGFR mutation-positive (Exon19Del, n = 24; L858R, n = 18; G719X, n = 1) locally advanced or metastatic NSCLC who had not previously received EGFR tyrosine kinase inhibitor (EGFR TKI) therapy, received once-daily lazertinib 240 mg. EGFR mutation status was confirmed by local or central testing. The primary endpoint was objective response rate (ORR) assessed by blinded independent central review. Secondary efficacy endpoints included duration of response (DoR), disease control rate (DCR), progression-free survival (PFS), tumor shrinkage, and overall survival (OS). RESULTS: At the primary data cut-off (DCO; January 8, 2021), the ORR was 70 % (95 % confidence interval [CI]: 56.0-83.5), DCR was 86 % (95 % CI: 75.7-96.4) and the median DoR was 23.5 (95 % CI: 12.5-not reached) months. The median PFS was 24.6 (95 % CI: 12.2-30.2) months. At the final DCO (March 30, 2023), the median OS was not estimable and the median follow-up duration for OS was 55.2 [95 % CI: 22.8-55.7] months. OS rates at 36 months and 54 months were 66 % (95 % CI: 47.5-79.3 %) and 55 % (95 % CI: 36.6-70.7 %), respectively. The most commonly reported TEAEs were rash (54 %), diarrhea (47 %), pruritus (35 %), and paresthesia (35 %). No drug-related rash or pruritus TEAEs of grade 3 or higher were reported. Diarrhea and paresthesia of grade 3 or higher were reported in 3 (7 %) and 1 (2 %) patients, respectively. CONCLUSION: This analysis demonstrated long-term clinical benefit with lazertinib 240 mg in patients with EGFR-mutated NSCLC who had not previously received EGFR TKIs. The safety profile for lazertinib was tolerable and consistent with that previously reported.

Comparison of the Vitek 2, MicroScan, and Etest methods with the agar dilution method in assessing colistin susceptibility of bloodstream isolates of Acinetobacter species from a Korean university hospital.

We evaluated three commercial colistin susceptibility testing methods using 213 bloodstream Acinetobacter isolates identified by gene sequencing. Compared to the agar dilution reference method, excellent categorical agreements (both 99.1%) were observed using Vitek 2 and Etest, compared to 87.3% (95.7% for Acinetobacter baumannii and 80.7% for non-baumannii Acinetobacter isolates) using MicroScan.

Accuracy of species-level identification of yeast isolates from blood cultures from 10 university hospitals in South Korea by use of the matrix-assisted laser desorption ionization-time of flight mass spectrometry-based Vitek MS system.

We assessed the accuracy of yeast bloodstream isolate identification performed over a 1-year period at 10 South Korean hospitals, using the matrix-assisted laser desorption ionization-time of flight (MALDI-TOF)-based Vitek MS system. The overall phenotypic misidentification rate was 3.4% (18/533), with considerable variation between hospitals (0.0% to 19.0%), compared to 1.1% (6/533) for the Vitek MS system.

Expression of SAP5 and SAP9 in Candida albicans biofilms: comparison of bloodstream isolates with isolates from other sources.

Secreted aspartic proteases (Sap), encoded by a family of 10 SAP genes, are key virulence determinants in Candida albicans. Although biofilm-associated bloodstream infections (BSIs) are frequently caused by C. albicans, SAP gene expression in C. albicans biofilms formed by BSI isolates has not been evaluated. We compared the expression of two SAP genes, SAP5 and SAP9, in C. albicans biofilms formed by BSI isolates with those formed by isolates from other body sites. Sixty-three C. albicans isolates were analyzed, comprising 35 BSI isolates and 28 from other sites. A denture-strip biofilm model was used, and expression of the two SAP genes was quantified by real-time RT-PCR during planktonic or biofilm growth. Mean SAP5 expression levels of the BSI isolates were 3.59-fold and 3.86-fold higher in 24-h and 48-h biofilms, respectively, than in planktonic cells. These results did not differ from those for isolates from other sites (2.71-fold and 2.8-fold for 24-h and 48-h biofilms, respectively). By contrast, mean SAP9 expression during biofilm formation was higher in BSI isolates (2.89-fold and 3.29-fold at 24 and 48 h, respectively) than in isolates from other sites (1.27-fold and 1.32-fold at 24 and 48 h, respectively; both, P < 0.001). These results show, for the first time, that both SAP5 and SAP9 are upregulated in C. albicans biofilms formed by BSI isolates, and that BSI isolates may have a greater capacity to express SAP9 under biofilm conditions than isolates from other sites.

Genetic diversity among Korean Candida albicans bloodstream isolates: assessment by multilocus sequence typing and restriction endonuclease analysis of genomic DNA by use of BssHII.

Multilocus sequence typing (MLST) has been successfully applied to the epidemiology of Candida albicans isolates not only within the hospital setting but also in multiple locations nationwide. We performed MLST to investigate the genetic relatedness among bloodstream infection (BSI) isolates of C. albicans recovered from 10 Korean hospitals over a 12-month period. The 156 isolates yielded 112 unique diploid sequence types (DSTs). While 95 DSTs were each derived from a single isolate, 17 DSTs were shared by 61 isolates (39.1%). Interestingly, 111 (71.1%) isolates clustered within previously known clades, and 29 (18.6%) clustered within a new clade that includes strains of Asian origin previously typed as singletons. This MLST study was complemented by restriction endonuclease analysis of genomic DNA using BssHII (REAG-B) in order to evaluate whether strains with identical DSTs and originating from the same hospital corresponded to nosocomial clusters. Importantly, only those isolates with a strong epidemiological relationship showed ≥95% identical REAG-B types. Our results indicate that REAG-B typing can be complementary to MLST but should be limited to the investigation of isolates of identical DSTs and when interhuman transmission is suspected.

Biofilm formation and genotyping of Candida haemulonii, Candida pseudohaemulonii, and a proposed new species (Candida auris) isolates from Korea.

Emergence of Candida haemulonii and closely related species at five Korean hospitals has been recently described. We examined biofilm formation by these isolates and assessed their genotypic relatedness by pulsed-field gel electrophoresis (PFGE). This study is the first to show that all bloodstream isolates of Candida pseudohaemulonii can form significant biofilms in glucose-containing medium. PFGE of NotI-digested genomic DNA revealed that C. pseudohaemulonii isolates recovered from seven patients in two hospitals shared five patterns, and that 15 isolates of a proposed new species (Candida auris) obtained from patients at three hospitals shared seven patterns, suggesting that some of these isolates may be related to clonal transmission.

Antifungal Susceptibility Tests and the cyp51 Mutant Strains among Clinical Aspergillus fumigatus Isolates from Korean Multicenters.

We investigated the antifungal susceptibilities and the cyp51 mutant strains among Aspergillus fumigatus clinical isolates obtained from 10 university hospitals in Korea. Of the 84 isolates examined, two itraconazole-resistant isolates were found with no amino acid substitution in the cyp51A/cyp51B genes. However, 19 (23.2%) azole-susceptible isolates harbored amino acid substitutions: Nine isolates harbored one to five mutations in cyp51A with high polymorphism, and 11 isolates exhibited the same Q42L mutation in cyp51B. Overall, a low azole resistance rate and high frequency of cyp51A/cyp51B amino acid substitutions were observed in the azole-susceptible A. fumigatus isolates in Korea.

NO-dependent attenuation of TPA-induced immunoinflammatory skin changes in Balb/c mice by pindolol, heptaminol or ATRA, but not by verapamil.

Recently a mouse skin carcinogenesis study reported that a ß-blocker carvedilol displayed antitumor-properties via antihyperplastic effects. However, the antihyperplastic mechanism is unclear as the ß-blocker is characterized with multiple pleiotropic effects including stimulation of endothelial NO release and verapamil-like calcium channel blocking activity. To investigate the nature and the origin of the antihyperplastic effects, we tested topical pretreatment with pindolol, heptaminol, ATRA or verapamil against Balb/c mouse ear skin hyperplasia that was induced by TPA. We found that pindolol, heptaminol or ATRA, but not verapamil, inhibited the TPA-induced immunoinflammatory skin changes in an NO-dependent manner, which included epidermal hyperplasia, skin edema and fibrosis. Furthermore, we also observed NO-dependent alleviation of the TPA-induced NK cell depletion in the ear tissues by heptaminol pretreatment. Together our results suggest that stimulation of NO generation from constitutive synthases may be primarily responsible for the reported antihyperplastic and NK cell-preserving effects of the ß-blockers, and that similar effects may be observed in other immunity normalizing compounds that also promote endothelial NO synthesis.

Evaluation of the BD Phoenix system for identification of a wide spectrum of clinically important yeast species: a comparison with Vitek 2-YST.

The Phoenix Yeast ID and Vitek 2-YST panels were compared using 351 molecularly identified yeast isolates. The Phoenix showed a comparable rate of correct identification for 4 common (Phoenix, 98%; Vitek, 94%) and 45 uncommon species (Phoenix, 70%; Vitek, 64%) and had a shorter mean identification time (6-7 h).