A cluster of Candida parapsilosis displaying fluconazole-trailing in a neonatal intensive care unit successfully contained by multiple infection-control interventions.

Objective: This study aimed to investigate and contain a cluster of invasive candidiasis cases caused by fluconazole-resistant Candida parapsilosis (FRC) in a neonatal intensive care unit. Methods: Active surveillance was initiated. Direct observations of hand-hygiene compliance (HHC) among staff were conducted before and after the implementation of hand-hygiene (HH) education. Thirty-five environmental cultures were obtained. Phylogenetic analysis of FRC was performed using Fourier-transform infrared spectroscopy and microsatellite genotyping. Results: A total of 14 patients (mean birth weight = 860 g, gestational age = 25 weeks) infected with FRC were identified using the fully automated analyzer, including 5 with clinical infection (three with catheter-related bloodstream infection, one with cutaneous infection, and one with fatal peritonitis) and 9 with colonization. The HHC rate in nurses before performing a sterile or aseptic procedure significantly improved after the HH education (P < .05). Sinks near the patients were contaminated with FRC. All FRC strains were confirmed to be susceptible to fluconazole using the CLSI method, and the microdilution procedure indicated a trailing effect. Phylogenetic analysis showed that all the fluconazole-trailing isolates from patients were clustered together and had the same genotype. Sinks were successfully decontaminated using accelerated hydrogen peroxide and drainage pipes were replaced. Ultraviolet-C decontamination was applied in the milk preparation room. No new cases were detected after the education and disinfection interventions. Conclusions: Sinks are an important reservoir of C. parapsilosis. Active surveillance, environmental hygiene, and constant staff education on maintaining a high level of HHC are necessary to limit the spread of C. parapsilosis.

Blood Culture Result Profile in Patients With Central Line-Associated Bloodstream Infection (CLABSI): A Single-Center Experience.

Background Central line-associated bloodstream infection (CLABSI) is among the most common bloodstream infections in the university hospital and intensive care unit settings. This study evaluated the routine blood test findings and microbe profiles of bloodstream infection (BSI) by the presence and types of central vein (CV) access devices (CVADs). Methods A total of 878 inpatients at a university hospital who were clinically suspected for BSI and underwent blood culture (BC) testing between April 2020 and September 2020 were enrolled. Data regarding age at BC testing, sex, WBC count, serum C-reactive protein (CRP) level, BC test results, yielded microbes, and usage and types of CVADs were evaluated. Results The BC yields were detected in 173 patients (20%), suspected contaminating pathogens in 57 (6.5%), and 648 (74%) with a negative yield. The WBC count (p=0.0882) and CRP level (p=0.2753) did not significantly differ between the 173 patients with BSI and the 648 patients with negative BC yields. Among the 173 patients with BSI, 74 used CVADs and met the diagnosis of CLABSI; 48 had a CV catheter, 16 had CV access ports, and 10 had a peripherally inserted central catheter (PICC). Patients with CLABSI showed lower WBC counts (p=0.0082) and serum CRP levels (p=0.0024) compared to those with BSI who did not use CVADs. The most commonly yielded microbes in those with CV catheters, CV-ports, and PICC were Staphylococcus epidermidis (n=9; 19%), Staphylococcus aureus (n=6; 38%), and S. epidermidis (n=8; 80%), respectively. Among those with BSI who did not use CVADs, Escherichia coli (n=31; 31%) was the most common pathogen, followed by S. aureus (n=13; 13%). Conclusion Patients with CLABSI showed lower WBC counts and CRP levels than those with BSI who did not use CVADs. Staphylococcus epidermidis was among the most common microbes in CLABSI and accounted for the majority of yielded microbes in patients who used PICC.

Evaluation of the performance of GeneSoC®, a novel rapid real-time PCR system, to detect Staphylococcus aureus and methicillin resistance in blood cultures.

Staphylococcus aureus bacteremia results in substantial mortality. Rapid identification and the determination of methicillin susceptibility are crucial for immediate treatment with appropriate antibiotics. In the present study, we aimed to evaluate the basic assay performance of GeneSoC®, a novel rapid quantitative polymerase chain reaction (qPCR) method, for the detection of methicillin-susceptible (MS) or -resistant (MR) S. aureus in blood culture (BC) bottles. qPCR pimers and probes were desinged for femA and mecA genes to diagnose S. aureus and its methicilline-resistance status. GeneSoC® system can detect target genes within 12 min per sample using microfludic thermal cycling. A total of 100 BC-positive samples, showing clusters of gram-positive cocci using microscopy, were tested. The analytical sensitivity was demonstrated for the target sequence of femA and mecA genes at 10 copies/µL, respectively. The detection limit of the MRSA bacterial burden using this system was 104 and 103 CFU/mL for femA and mecA, respectively. Compared with culture-based identification and susceptibility testing, the sensitivity and specificity for the detection of femA (+)/mecA (+) MRSA using GeneSoC® were 90.9 and 98.9%, respectively, whereas the sensitivity and specificity for detection of femA (+)/mecA (-) MSSA were 96.2% and 97.3%, respectively. In conclusion, although this was a small sample and pilot study, the GeneSoC® system is beneficial for rapid, reliable, and highly sensitive real-time testing of MRSA and MSSA in BC bottles.

Clinical and Epidemiological Characteristics of Persistent Bacteremia: A Decadal Observational Study.

Background: Bloodstream infections (BSIs), including persistent bacteremia (PB), are a leading source of morbidity and mortality globally. PB has a higher mortality rate than non- PB, but the clinical aspects of PB in terms of the causative pathogens and the presence of clearance of PB are not well elucidated. Therefore, this study aimed to describe the clinical and epidemiological characteristics of PB in a real-world clinical setting. Methods: We performed a retrospective observational survey of patients who underwent blood culture between January 2012 and December 2021 at Tohoku University Hospital. Cases of PB were divided into three groups depending on the causative pathogen: gram-positive cocci (GPC), gram-negative rods (GNRs), and Candida spp. For each group, we examined the clinical and epidemiological characteristics of PB, including differences in clinical features depending on the clearance of PB. The main outcome variable was mortality, assessed as early (30-day), late (30-90 day), and 90-day mortality. Results: Overall, we identified 31,591 cases of single bacteremia; in 6709 (21.2%) cases, the first blood culture was positive, and in 3124 (46.6%) cases, a follow-up blood culture (FUBC) was performed. Of the cases with FUBCs, 414 (13.2%) were confirmed to be PB. The proportion of PB cases caused by Candida spp. was significantly higher (29.6%, 67/226 episodes) than that for GPC (11.1%, 220/1974 episodes, p < 0.001) and GNRs (12.1%, 100/824 episodes, p < 0.001). The Candida spp. group also had the highest late (30-90 day) and 90-day mortality rates. In all three pathogen groups, the subgroup without the clearance of PB tended to have a higher mortality rate than the subgroup with clearance. Conclusions: Patients with PB due to Candida spp. have a higher late (30-90 day) and 90-day mortality rate than patients with PB due to GPC or GNRs. In patients with PB, FUBCs and confirming the clearance of PB are useful to improve the survival rate.

Serine hydroxymethyltransferase as a potential target of antibacterial agents acting synergistically with one-carbon metabolism-related inhibitors.

Serine hydroxymethyltransferase (SHMT) produces 5,10-methylenetetrahydrofolate (CH2-THF) from tetrahydrofolate with serine to glycine conversion. SHMT is a potential drug target in parasites, viruses and cancer. (+)-SHIN-1 was developed as a human SHMT inhibitor for cancer therapy. However, the potential of SHMT as an antibacterial target is unknown. Here, we show that (+)-SHIN-1 bacteriostatically inhibits the growth of Enterococcus faecium at a 50% effective concentration of 10-11 M and synergistically enhances the antibacterial activities of several nucleoside analogues. Our results, including crystal structure analysis, indicate that (+)-SHIN-1 binds tightly to E. faecium SHMT (efmSHMT). Two variable loops in SHMT are crucial for inhibitor binding, and serine binding to efmSHMT enhances the affinity of (+)-SHIN-1 by stabilising the loop structure of efmSHMT. The findings highlight the potency of SHMT as an antibacterial target and the possibility of developing SHMT inhibitors for treating bacterial, viral and parasitic infections and cancer.

Chromobacterium haemolyticum Pneumonia Associated with Near-Drowning and River Water, Japan.

We report a severe case of Chromobacterium haemolyticum pneumonia associated with near-drowning and detail the investigation of the pathogen and river water. Our genomic and environmental investigation demonstrated that river water in a temperate region can be a source of C. haemolyticum causing human infections.

Pyrimidine Analogues as a New Class of Gram-Positive Antibiotics, Mainly Targeting Thymineless-Death Related Proteins.

Multidrug-resistant (MDR) bacteria are widespread throughout the world and pose an increasingly serious threat to human and animal health. Besides implementing strict measures to prevent improper antibiotic use, it remains essential that novel antibiotics must be developed. These antibiotics need to exert their activity via mechanisms different from those employed by currently approved antibiotics. In this study, we used several 5-fluorouracil (5-FU) analogues as chemical probes and investigated the potential of these pyrimidine analogues as antibacterial agents. Several 5-FU derivatives exerted potent activity against strains of Gram-positive cocci (GPC) that are susceptible or resistant toward approved antibiotics, without showing cross-resistance. Furthermore, we have provided evidence that the pyrimidine analogues exerted anti-GPC activity via thymineless death by inhibition of thymidylate synthetase (ThyA) and/or inhibition of RNA synthesis. Interestingly, whole genome resequencing of in vitro-selected, pyrimidine analogue-resistant Staphylococcus aureus mutants indicated that S. aureus strains with pyrimidine-analogue resistance induced an amino acid (AA) substitution, deletion, and/or insertion into thymineless-death related proteins except for ThyA, or enhanced the ThyA transcription level. Thus, S. aureus may avoid altering the ThyA function by introducing an AA substitution, suggesting that the pyrimidine analogues, which directly bind to ThyA without phosphorylation, may be more effective and show a higher genetic barrier than the pyrimidines that depend on phosphorylation for activity. The findings of this study may assist in the future development of a novel class of antibiotics for combating MDR GPC, including methicillin-resistant S. aureus and vancomycin-resistant Enterococci.

Evaluation of the FilmArray Blood Culture Identification Panel on Detection of Pathogenic Microorganisms in Positive Blood Cultures: the First Clinical Report in Japan.

FilmArray (FA) is a multiplex PCR-based desktop microbial detection system. The blood culture identification (BCID) panel is an adaptable panel for FA, which diagnoses sepsis and/or systemic infections by detecting 14 bacterial species, 4 bacterial genera, 1 bacterial family, 5 yeast species, and 3 antimicrobial resistance genes (mecA, Klebsiella pneumoniae carbapenemase [KPC], and vanA/B) in positive blood cultures within 1 h. We retrospectively evaluated the FA-BCID panel using 54 positive blood cultures, in which 57 bacterial and 3 yeast strains were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The FA-BCID panel revealed 59 microorganisms in 53 samples; this performance was similar to that of MALDI-TOF MS analysis; however, 1 bacterium in 1 sample was not detected. In addition, mecA genes were detected in 12 Staphylococcus species, which all manifested methicillin resistance in susceptibility testing, whereas genes KPC and vanA/B were not detected, in agreement with the results of antimicrobial susceptibility testing. Although more information on antimicrobial resistance, including activity of IMP-metallo-ß-lactamases, is required in Japan, the FA-BCID panel can detect pathogenic microorganisms in positive blood cultures rapidly, and this method could be beneficial for proper treatment of sepsis and/or systemic infections, especially in small hospitals.