Tolerance of clinical vancomycin-resistant Enterococcus faecium isolates against UV-C light from a mobile source.

BACKGROUND: Admission to a room previously occupied by patients carrying environmentally robust pathogens implies an increased risk of acquiring those pathogens. Therefore, 'No-touch' automated room disinfection systems, including devices based on UV-C irradiation, are discussed to improve terminal cleaning. It is still unclear if clinical isolates of relevant pathogens behave differently under UV-C irradiation compared to laboratory strains used in the approval process of disinfection procedures. In this study we analysed the susceptibility of well characterized clonally divergent vancomycin-resistant enterococci (VRE) strains, including a linezolid-resistant isolate, against UV-C radiation. METHODS: Susceptibility against UV-C of ten clonally divergent clinical isolates of VRE was determined in comparison to the commonly used test organism Enterococcus hirae ATCC 10541. Ceramic tiles contaminated with 105 to 106 colony forming units/25 cm² of the different enterococci were positioned at a distance of 1.0 and 1.5 m and irradiated for 20 s, resulting in a UV-C dose of 50 and 22 mJ/cm², respectively. Reduction factors were calculated after quantitative culture of the bacteria recovered from treated and untreated surfaces. RESULTS: Susceptibility to UV-C varied considerably among the strains studied, with the mean value of the most robust strain being up to a power of ten lower compared to the most sensitive strain at both UV-C doses. The two most tolerant strains belonged to MLST sequence types ST80 and ST1283. The susceptibility of the laboratory strain E. hirae ATCC 10541 ranged between the most sensitive and most tolerant isolates for both irradiation doses. However, for UV-C dose of 22 mJ/cm², the reduction of the most tolerant isolate of ST1283 was statistically significantly lower compared to E. hirae ATCC 10541. The most susceptible strains belonged to the MLST sequence types ST117 and ST203. CONCLUSIONS: These results indicate that UV-C doses reported in the literature are sufficient for the reduction of commonly used reference strains of enterococci but could be insufficient for the reduction of tolerant patient VRE-isolates in a hospital setting. Therefore, for future studies, the most tolerant clinical isolates should be used to validate automated UV-C devices or longer exposure times should be expected to ensure efficacy in the real world.

[Puzzling B symptoms in a 61-year-old patient under treatment for rheumatoid arthritis]. / Rätselhafte B-Symptomatik bei einem 61-Jährigen unter Therapie einer rheumatoiden Arthritis.

A patient with rheumatoid arthritis and immunosuppression developed symptoms of wasting, neuropathy and lung cavitations eventually leading to central nervous system symptoms and fatal multi-organ failure. Disseminated infection with Histoplasma capsulatum proved to be the underlying cause. The primary infection had apparently been acquired 4 years earlier on a holiday to the Caribbean. Rare infectious diseases should be considered in patients under immunosuppression and travel activities to specific endemic areas.

Voriconazole plus terbinafine combination antifungal therapy for invasive Lomentospora prolificans infections: analysis of 41 patients from the FungiScope® registry 2008-2019.

OBJECTIVES: Lomentospora prolificans is an emerging cause of serious invasive fungal infections. Optimal treatment of these infections is unknown, although voriconazole-containing treatment regimens are considered the treatment of choice. The objective of this study was to evaluate the role of combination antifungal therapy for L. prolificans infections. METHODS: We performed a retrospective review of medical records of patients with invasive L. prolificans infection diagnosed between 1 January 2008 and 9 September 2019 that were documented in the FungiScope® registry of rare invasive fungal infections. We compared clinical outcomes between antifungal treatment strategies. RESULTS: Over the study period, 41 individuals with invasive L. prolificans infection from eight different countries were documented in the FungiScope® registry. Overall, 17/40 (43%) had treatment response/stable disease and 21/40 (53%) had a fatal outcome attributed to invasive fungal infection. Combination antifungal therapy was associated with increased 28-day survival (15/24 survived versus 4/16 receiving monotherapy; p 0.027) and the combination voriconazole plus terbinafine trended to be associated with higher rates of treatment success (10/16, 63%, 95% CI 35%-85%) compared with other antifungal treatment regimens (7/24, 29%, 95% CI 13%-51%, p 0.053). In Kaplan-Meier survival analysis there was a higher survival probability in individuals receiving the voriconazole/terbinafine combination compared with other antifungal regimens (median survival 150 days versus 17 days). CONCLUSIONS: While overall mortality was high, combination antifungal treatment, and in particular combination therapy with voriconazole plus terbinafine may be associated with improved treatment outcomes compared with other antifungal regimens for the treatment of invasive L. prolificans infections.

Rapid identification of the vanA/vanB resistance determinant in Enterococcus sp. from blood cultures using the Cepheid Xpert vanA/vanB cartridge system.

Especially in immunocompromised and intensive care patients VRE sepsis is associated with high mortality. The GeneXpert vanA/vanB assay is marketed for fast molecular surveillance of VRE colonization in peri-anal and rectal swabs. The aim of this study was to evaluate this assay for its usefulness for rapid identification of the vanAB determinant from positive blood cultures. During an evaluation phase, 33/34 blood cultures (negative = 13; vanA = 1; and vanB = 19) were correctly identified. In the validation phase 205/211 blood cultures were correctly identified (negative, n = 160; vanA, n = 2; vanB, n = 43). Sensitivity and specificity calculated from valid tests was 100% (95% CI: 90.2-100%) and 100% (95% CI: 97.1-100%), respectively. The error rate was 2.8%. The Xpert vanA/vanB cartridge is a reliable tool in the rapid molecular identification of the vanA and vanB determinant from positive blood cultures with moderate inhibition rates (2.8%) and high PPV and NPV. However, additional methods for species identification are required.

Tedizolid susceptibility in linezolid- and vancomycin-resistant Enterococcus faecium isolates.

Vancomycin-resistant enterococci (VRE) are of ever-increasing importance, most notably in high-risk patient populations. Therapy options are often limited for these isolates, and apart from tigecycline and daptomycin, oxazolidinone linezolid is frequently administered. The broad usage of linezolid, however, has driven the emergence of linezolid-resistant VRE strains (LR-VRE), further shortening therapeutic options. Second-generation oxazolidinone tedizolid has the advantage of being active against a specific subset of LR-VRE, i.e. isolates expressing the plasmid-encoded chloramphenicol-florfenicol resistance (cfr) gene. Here we tested tedizolid activity in a collection of 30 LR Enterococcus faecium VRE (MIC range 32-256 mg/l) isolated between 2012 and 2015 from clinical and screening specimens. By pulsed field gel electrophoresis (PFGE) isolates were assigned to 16 clonal lineages. In three cases, linezolid-susceptible progenitor isolates of LR-VRE were isolated, thus demonstrating the de-novo emergence of the linezolid-resistant phenotype. PCR did not detect cfr, cfr(B) or novel oxazolidinone resistance gene optrA in LR-VRE. All isolates, however, carried mutations within the 23S rDNA. Compared to linezolid, tedizolid MICs were lower in all isolates (MIC range 2-32 mg/l), but remained above the FDA tedizolid breakpoint for E. faecalis at 0.5 mg/l. Thus, related to the predominant resistance mechanism, tedizolid is of limited value for treatment of most LR-VRE and represents a therapeutic option only for a limited subset of isolates.

Comparison of resistance against erythromycin and moxifloxacin, presence of binary toxin gene and PCR ribotypes in Clostridium difficile isolates from 1990 and 2008.

Worldwide increasing rates of Clostridium difficile infections (CDI) with severe courses and outbreaks have been reported. This change in CDI epidemiology has on one hand been related to the spread of specific PCR ribotypes (e.g. 027) and on the other hand to increased prevalence of resistant C. difficile strains. This single-centre retrospective analysis characterized resistance against erythromycin and moxifloxacin, presence of binary toxin gene and ribotypes in 73 C. difficile isolates from 2008 in comparison with 23 isolates from 1990. In 1990, five different PCR ribotypes including 027 were identified. Resistance against erythromycin was detected in 3 of 23 (13%), while 20 of 23 (87%) from all isolates were susceptible to both erythromycin and moxifloxacin. In contrast, in 2008 a significantly increased prevalence of resistant C. difficile strains was observed, with 40 of 73 (54.8%) isolates being resistant against both antibiotics. Resistant C. difficile strains were mainly assigned to PCR ribotype 001. No isolates belonging to PCR ribotype 027 were identified. Our data provide evidence that the increase of resistant C. difficile strains belonging to PCR ribotype 001 rather than the spread of C. difficile PCR ribotype 027 contribute to the changing epidemiology of CDI.

Combined ramR mutation and presence of a Tn1721-associated tet(A) variant in a clinical isolate of Salmonella enterica serovar Hadar resistant to tigecycline.

A Salmonella enterica serovar Hadar strain resistant to tigecycline (MIC, 16 microg/ml) was isolated. Molecular characterization revealed the presence of a plasmid-borne tet(A) variant associated with Tn1721 mediating a rise of the MIC for tigecycline when transferred to Escherichia coli. Additionally, a truncating mutation in ramR was detected. Transformation with wild-type ramR but not with the mutated ramR lowered the MIC for tigecycline. Characterization of this Salmonella isolate implicates ramR in resistance to tigecycline.

Expression and functional characterization of gfpmut3.1 and its unstable variants in Staphylococcus epidermidis.

Reporter gene systems are an invaluable tool for investigation of gene transcription activity in eukaryotes and prokaryotes. In order to analyze the temporal and spatial resolution of gene expression patterns in situ and for quantitatively investigating gene expression, the green fluorescent protein (GFP) appears to be especially useful. GFP has been broadly used in various bacterial species, however, there is only limited knowledge about key biological properties in S. epidermidis. Here, the crucial influence of different ribosomal binding sites (RBS) on gfpmut3.1 translation initiation in S. epidermidis 1457 is demonstrated. Only by using the RBS of the delta-hemolysin promoter, after 24 hours a strong fluorescence signal was obtained. The half-life of GFPmut3.1 in S. epidermidis 1457 was significantly shorter than in E. coli (7 h vs. 24 h). GFPmut3.1 derivatives with shorter half-lives (GFP(AAV) and GFP(ASV)) did not reach sufficient quantitative protein levels, and the resulting low fluorescence limits their use as reporter genes in S. epidermidis. This work provides fundamental insights into gfpmut3.1 expression in S. epidermidis and describes the crucial determinants of its biological behavior in this species. In general, this study underlines the need to accurately characterize key biological properties of this transcription marker in gram-positive hosts.

Design considerations of CareWindows, a Windows 3.0-based graphical front end to a Medical Information Management System using a pass-through-requester architecture.

The Care Windows development project demonstrated the feasibility of an approach designed to add the benefits of an event-driven, graphically-oriented user interface to an existing Medical Information Management System (MIMS) without overstepping economic and logistic constraints. The design solution selected for the Care Windows project incorporates three important design features: (1) the effective de-coupling of severs from requesters, permitting the use of an extensive pre-existing library of MIMS servers, (2) the off-loading of program control functions of the requesters to the workstation processor, reducing the load per transaction on central resources and permitting the use of object-oriented development environments available for microcomputers, (3) the selection of a low end, GUI-capable workstation consisting of a PC-compatible personal computer running Microsoft Windows 3.0, and (4) the development of a highly layered, modular workstation application, permitting the development of interchangeable modules to insure portability and adaptability.

Medical Information Management System (MIMS) CareWindows.

The demonstration of MIMS/CareWindows will include: (1) a review of the application environment and development history, (2) a demonstration of a very large, comprehensive clinical information system with a cost effective graphic user server and communications interface.