Prevalence and Molecular Characterization of Vancomycin Variable Enterococcus faecium Isolated From Clinical Specimens.

Vancomycin variable Enterococcus (VVE) bacteria are phenotypically susceptible to vancomycin, but they harbor the vanA gene. We aimed to ascertain the prevalence of VVE among clinically isolated vancomycin-susceptible Enterococcus faecium (VSE) isolates, as well as elucidate the molecular characteristics of the vanA gene cluster within these isolates. Notably, we investigated the prevalence and structure of the vanA gene cluster of VVE. Between June 2021 and May 2022, we collected consecutive, non-duplicated vancomycin-susceptible Enterococcus faecium (VSE) samples. Real-time PCR was performed to detect the presence of vanA, vanB, and vanC. Overlapping PCR with sequencing and whole-genome sequencing were performed for structural analysis. Sequence types (STs) were determined by multilocus sequence typing. Exposure testing was performed to assess the ability of the isolates to acquire vancomycin resistance. Among 282 VSE isolates tested, 20 isolates (7.1%) were VVE. Among them, 17 isolates had partial deletions in the IS1216 or IS1542 sequences in vanS (N=10), vanR (N=5), or vanH (N=2). All VVE isolates belonged to the CC17 complex and comprised five STs, namely ST17 (40.0%), ST1421 (25.0%), ST80 (25.0%), ST787 (5.0%), and ST981 (5.0%). Most isolates were related to three hospital-associated clones (ST17, ST1421, and ST80). After vancomycin exposure, 18 of the 20 VVEs acquired vancomycin resistance. Considering the high reversion rate, detecting VVE by screening VSE for vanA is critical for appropriate treatment and infection control.

Evaluation of the BioFire® FilmArray® Pneumonia Panel with Conventional Bacterial Culture in Conjunction with Leukocyte Esterase Test.

We evaluated the performance of the BioFire® FilmArray® Pneumonia panel (PN-panel) in detecting bacterial pathogens by comparing it to cultures and to the usefulness of the leukocyte esterase (LE) urine strip test. Between January and June 2022, a total of 67 sputum specimens were obtained from community-acquired pneumonia patients. The PN-panel and LE test were performed simultaneously with conventional cultures. The pathogen detection rates of the PN-panel and culture were 40/67 (59.7%) and 25/67 (37.3%), respectively. The concordance rate between the PN-panel and culture was high (76.9%) when the bacterial burden was high (107 copies/mL), but it was low (8.6%) when it was 104-6 copies/mL, irrespective of the sputum quality. According to the LE positivity, the overall culture positive rate and PN-panel positive rate were significantly higher among the LE-positive specimens (23/45, 31/45) than among the LE-negative specimens (2/21, 8/21). Moreover, the difference in concordance rate between the PN-panel test and culture was significant according to the LE positivity, but not the Gram stain grading. In conclusion, the PN-panel showed high concordance when the bacterial burden was high (107 copies/mL) and ancillary use of LE test will be helpful in interpreting the PN-panel results, especially when the copy number of bacterial pathogens is low.

Identification of the rare yeast Cutaneotrichosporon (Trichosporon) debeurmannianum from diabetic foot infection.

BACKGROUND: Diabetic foot infection is the most common complications of diabetes mellitus. Although most of the diabetic foot infections has been known to be caused by aerobic and anaerobic bacteria, mycotic diabetic foot infection caused by Candida species has also been reported recently. Here, we present the first case of diabetic foot infection caused by Cutaneotrichosporon debeurmannianum (previously known as Trichosporon debeurmannianum). METHODS: A 68-year-old diabetic male patient was admitted for management of the necrosis of the big toe. Wound swab culture was performed three times, and each time after 5 days of incubation, beige-colored, wrinkled, and rough colonies were observed on chocolate agar plate. RESULTS: The isolate was identified as C. debeurmannianum with the matrix-assisted laser desorption ionization-time of flight mass spectrometry system (MicroIDSys, ASTA corp.). For confirmation, the sequencing for ITS1/ITS2 and D1/D2 ribosomal DNA was also performed, and the isolate was confirmed as C. debeurmannianum with 100% identity. The isolate exhibited low minimum inhibitory concentrations (MICs) for azoles and high MICs for all echinocandins. CONCLUSION: Considering that usual incubation time for bacterial culture of open wound specimens is only 48 h, it is important to include the request for fungus culture to detect pathogen in diabetic foot lesion.

Predominance and clonal spread of CTX-M-15 in cefotaxime-resistant Klebsiella pneumoniae in Korea and their association with plasmid-mediated quinolone resistance determinants.

INTRODUCTION: ß-lactams and fluoroquinolones are extensively used worldwide in the treatment of infections caused by Enterobacterales. In this study, we investigated the prevalence of extended-spectrum ß-lactamases (ESBL), their correlation with plasmid-mediated quinolone resistance determinants (PMQR) and clonal distribution among the cefotaxime-resistant K. pneumoniae isolates. METHODS: In Korea, a total of 429 K. pneumoniae collected in 2015 were studied. Antimicrobial susceptibility test for cefotaxime, ciprofloxacin and levofloxacin was performed by broth microdilution method. By PCR and/or sequencing, mutations in gyrA and parC genes, PMQR genes and ESBL were identified. Multilocus-sequence-type (MLST) was determined for isolates harboring CTX-M-15. RESULTS: Among the 149 K. pneumoniae showing cefotaxime MICs of >1 µg/ml, 142 (95.3%) isolates were ESBL-producers and CTX-M-15 was predominant (99 isolates). Among the 142 ESBL-producers, mutations in gyrA and parC were found in 112 (78.9%) and 93 isolates (65.5%), respectively. PMQR genes were detected in 141 isolates and the non-susceptibility rate to ciprofloxacin and levofloxacin was 95.1% (135/142) and 82.4% (117/142), respectively. The most frequently found PMQR combination was qnrB-aac(6')-Ib-cr-oqxAB, (58/142, 40.8%). By MLST, four major STs/CC: ST48, ST392, ST307 and CC15 accounted for 67% of the CTX-M-15 producers and the prevalence of qnrB was significantly higher in these four major STs/CC than other groups (P = 0.004). Of note, we found the additive effect of PMQR genes; the more PMQR genes, the higher ciprofloxacin MICs. CONCLUSIONS: CTX-M-15 was predominant among the cefotaxime-resistant K. pneumoniae and co-harboring CTX-M-15 and PMQR genes, especially qnrB, seems to contribute the spread of high risk clones.