Intensity Ratio of Kß/Kα in Selected Elements from Mg to Cu, and the Chemical Effects of Cr Kα1,2 Diagram Lines and Cr Kß/Kα Intensity Ratio in Cr Compounds.

Kα,ß X-ray lines from photon excitation were measured in selected elements from Mg to Cu using a high-resolution double-crystal X-ray spectrometer with a proportional counter, and the Kß/Kα intensity ratio for each element was obtained, after correcting for self-absorption, detection efficiency, and crystal reflectance. This intensity ratio increases rapidly from Mg to Ca but, in the 3d elements region, the increase becomes slower. This is related to the intensity of the Kß line involving valence electrons. The slow increase of this ratio in the 3d elements region is thought to be due to the correlation between 3d and 4s electrons. Moreover, the chemical shifts, FWHM, asymmetry indices, and Kß/Kα intensity ratios of the Cr compounds, due to different valences, were also investigated using the same double-crystal X-ray spectrometer. The chemical effects were clearly observed, and the Kß/Kα intensity ratio was found to be compound-dependent for Cr.

Resolving taxonomic confusion: establishing the genus Phytobacter on the list of clinically relevant Enterobacteriaceae.

Although many clinically significant strains belonging to the family Enterobacteriaceae fall into a restricted number of genera and species, there is still a substantial number of isolates that elude this classification and for which proper identification remains challenging. With the current improvements in the field of genomics, it is not only possible to generate high-quality data to accurately identify individual nosocomial isolates at the species level and understand their pathogenic potential but also to analyse retrospectively the genome sequence databases to identify past recurrences of a specific organism, particularly those originally published under an incorrect or outdated taxonomy. We propose a general use of this approach to classify further clinically relevant taxa, i.e., Phytobacter spp., that have so far gone unrecognised due to unsatisfactory identification procedures in clinical diagnostics. Here, we present a genomics and literature-based approach to establish the importance of the genus Phytobacter as a clinically relevant member of the Enterobacteriaceae family.

The applicability of gene sequencing and MALDI-TOF to identify less common gram-negative rods (Advenella, Castellaniella, Kaistia, Pusillimonas and Sphingobacterium) from environmental isolates.

Our aim was to identify less common non-fermenting gram-negative rods during the bioremediation process. Five genera were found: Advenella, Castellaniella, Kaistia, Pusillimonas and Sphingobacterium, for a total of 15 isolates. Therefore, we evaluated the applicability of four methods currently available for bacteria identification: (1) conventional biochemical methods, (2) the VITEK®-2 system, (3) MALDI-TOF mass spectrometry and (4) 16S rRNA gene sequencing. The biochemical methods and the VITEK®-2 system were reliable only for the Sphingobacterium isolate and solely at the genus level. Both MALDI-TOF mass spectrometry platforms (Bruker and VITEK® MS) did not achieve reliable identification results for any of these genera. 16S rRNA gene sequencing identified eight isolates to the species level but not to the subspecies level, when applicable. The remaining seven isolates were reliably identified through 16S rRNA gene sequencing to the genus level only. Our findings suggest that the detection and identification of less common genera (and species) that appeared at certain moments during the bioremediation process can be a challenge to microbiologists considering the most used techniques. In addition, more studies are required to confirm our results.

Daptomycin Resistance and Tolerance Due to Loss of Function in Staphylococcus aureus dsp1 and asp23.

Lipopeptide daptomycin is a last-line cell-membrane-targeting antibiotic to treat multidrug-resistant Staphylococcus aureus Alarmingly, daptomycin-resistant S. aureus isolates have emerged. The mechanisms underlying daptomycin resistance are diverse and share similarities with resistances to cationic antimicrobial peptides and other lipopeptides, but they remain to be fully elucidated. We selected mutants with increased resistance to daptomycin from a library of transposon insertions in sequent type 8 (ST8) S. aureus HG003. Insertions conferring increased daptomycin resistance were localized to two genes, one coding for a hypothetical lipoprotein (SAOUHSC_00362, Dsp1), and the other for an alkaline shock protein (SAOUHSC_02441, Asp23). Markerless loss-of-function mutants were then generated for comparison. All transposon mutants and knockout strains exhibited increased daptomycin resistance compared to those of wild-type and complemented strains. Null and transposon insertion mutants also exhibited increased resistance to cationic antimicrobial peptides. Interestingly, the Δdsp1 mutant also showed increased resistance to vancomycin, a cell-wall-targeting drug with a different mode of action. Null mutations in both dsp1 and asp23 resulted in increased tolerance as reflected by reduced killing to both daptomycin and vancomycin, as well as an increased tolerance to surfactant (Triton X-100). Neither mutant exhibited increased resistance to lysostaphin, a cell-wall-targeting endopeptidase. These findings identified two genes core to the S. aureus species that make previously uncharacterized contributions to antimicrobial resistance and tolerance in S. aureus.

Dissemination of blaOXA-370 is mediated by IncX plasmids and the Tn6435 transposon.

In Enterobacteriaceae, the blaOXA-48-like genes have been identified on plasmids in different regions of the world. The OXA-370 is a plasmid-encoded OXA-48-like enzyme reported in two distinct regions of Brazil. Recently, we demonstrate that the blaOXA-370 gene is disseminated among several Enterobacteriaceae species and clones, indicating a high potential for dissemination. In this work, we described for the first time the complete nucleotide sequence of six plasmids harboring the blaOXA-370 gene. Complete DNA sequencing using the Illumina platform and annotation of the plasmids showed that they belonged to incompatibility groups IncX and had in average 70 kbp. The blaOXA-370 gene is located in a composite transposon containing four genes encoding transposases, named Tn6435. In this study, highly similar plasmids were detected in different Enterobacteriaceae genera.

Flagellar Cap Protein FliD Mediates Adherence of Atypical Enteropathogenic Escherichia coli to Enterocyte Microvilli.

The expression of flagella correlates with different aspects of bacterial pathogenicity, ranging from adherence to host cells to activation of inflammatory responses by the innate immune system. In the present study, we investigated the role of flagella in the adherence of an atypical enteropathogenic Escherichia coli (aEPEC) strain (serotype O51:H40) to human enterocytes. Accordingly, isogenic mutants deficient in flagellin (FliC), the flagellar structural subunit; the flagellar cap protein (FliD); or the MotAB proteins, involved in the control of flagellar motion, were generated and tested for binding to differentiated Caco-2 cells. Binding of the aEPEC strain to enterocytes was significantly impaired in strains with the fliCa nd fliD genes deleted, both of which could not form flagella on the bacterial surface. A nonmotile but flagellated MotAB mutant also showed impaired adhesion to Caco-2 cells. In accordance with these observations, adhesion of a EPEC strain 1711-4 to Caco-2 cells was drastically reduced after the treatment of Caco-2 cells with purified FliD. In addition, incubation of a EPEC bacteria with specific anti-FliD serum impaired binding to Caco-2 cells. Finally, incubation of Caco-2 cells with purified FliD, followed by immunolabeling, showed that the protein was specifically bound to the microvillus tips of differentiated Caco-2 cells. The a EPEC FliD or anti-FliD serum also reduced the adherence of prototype typical enteropathogenic, enterohemorrhagic, and enterotoxigenic E. coli strains to Caco-2 cells. In conclusion, our findings further strengthened the role of flagella in the adherence of a EPEC to human enterocytes and disclosed the relevant structural and functional involvement of FliD in the adhesion process.

Frequency of BKC-1-Producing Klebsiella Species Isolates.

BKC-1 is a new class A serine carbapenemase that was recently identified in Klebsiella pneumoniae clinical isolates. The principal objective of this study was to evaluate the frequency of blaBKC-1 by testing a collection of Klebsiella isolates. Only 2 of 635 Klebsiella isolates (0.3%) carried blaBKC-1 The two BKC-1-producing isolates belonged to clonal complex 442 and possessed identical pulsed-field gel electrophoresis patterns. The blaBKC-1 gene was inserted into a 10-kb plasmid that was identical to the previously reported plasmid, p60136. The BKC-producing K. pneumoniae isolates presented also possessed other mechanisms for beta-lactam resistance, such as genes encoding extended-spectrum beta-lactamases and mutations in the genes ompK35 and ompK36, encoding the major porins.

fosI Is a New Integron-Associated Gene Cassette Encoding Reduced Susceptibility to Fosfomycin.

In this work, we demonstrate that the fosI gene encodes a predicted small protein with 134 amino acids and determines reduced susceptibility to fosfomycin. It raised the MIC from 0.125 to 6 µg/ml when the pBRA100 plasmid was introduced into Escherichia coli TOP10 and to 16 µg/ml when the gene was cloned into the pBC_SK(-) vector and expressed in E. coli TOP10.

Emergence of Acinetobacter baumannii ST730 carrying the blaOXA-72 gene in Brazil.

Over the last decade, Acinetobacter baumannii resistant to carbapenems has emerged in many medical centres and has been commonly associated with high morbimortality. In Brazil, this resistance is mainly attributed to the spread of OXA-23-producing clones and, to a lesser extent, to OXA-143-producing clones. Here, we describe, for the first time, two OXA-72-producing A. baumannii isolates in southern Brazil to a broad spectrum of antibiotics, except polymyxin B and tigecycline. Molecular typing by multilocus sequence typing (MLST) demonstrated that both OXA-72-producing isolates belong to a new sequence type (ST), ST730, which was recently identified in OXA-23-producing A. baumannii isolates in São Paulo, Brazil. We demonstrate that the two A. baumannii ST730 isolates carrying blaOXA-72share a common ancestral origin with the blaOXA-23producers in Brazil. This observation reinforces the importance of strain-typing methods in order to clarify the dynamics of the emergence of new clones in a geographic region.

Caffeine Attenuates Decreases in Leg Power Without Increased Muscle Damage.

Ribeiro, BG, Morales, AP, Sampaio-Jorge, F, Barth, T, de Oliveira, MBC, Coelho, GMdO, and Leite, TC. Caffeine attenuates decreases in leg power without increased muscle damage. J Strength Cond Res 30(8): 2354-2360, 2016-Caffeine ingestion has been shown to be an effective ergogenic aid in several sports. Caffeine administration may increase exercise capacity, which could lead to a greater degree of muscle damage after exercise. This was a randomized, double-blind, placebo-controlled crossover study. Six male handball athletes ingested placebo (PLA) or caffeine (CAF) (6 mg·kg body mass) capsules on 2 different occasions. Sixty minutes after ingestion of the capsules, serum CAF levels were evaluated. Thereafter, all participants performed a protocol of vertical jumps (VJs). The protocol consisted of 4 sets of 30 seconds of continuous VJs with 60 seconds of recovery between sets. Blood lactate (LAC) and creatine kinase (CK) levels were determined before and after the protocol. We found significant differences in serum CAF levels between PLA (0.09 ± 0.18 µg·ml) vs. CAF (6.59 ± 4.44 µg·ml) (p < 0.001). Caffeine elicited a 5.23% (p ≤ 0.05) improvement in the leg power compared with PLA. The CAF trial displayed higher LAC (p ≤ 0.05) compared with PLA (6.26 ± 2.01 vs. 4.39 ± 2.42 mmol·L, respectively) after protocol of VJs, whereas no difference in CK was observed between trials (p > 0.05). These results indicate that immediate ingestion of CAF (6 mg·kg body weight) can reduce the level of muscle fatigue and preserve leg power during the test, possibly resulting in increase in LAC. There was no increase in muscle damage, which indicates that immediate administration of (6 mg·kg body weight) CAF is safe. Thus, nutritional interventions with CAF could help athletes withstand a greater physiological overload during high-intensity training sessions. The results of this study would be applicable to sports and activities that require repetitive leg power.

Characterization of Tn3000, a Transposon Responsible for blaNDM-1 Dissemination among Enterobacteriaceae in Brazil, Nepal, Morocco, and India.

In Enterobacteriaceae, the blaNDM genes have been found in many different genetic contexts, and a wide diversity of plasmid scaffolds bearing those genes has been found. In August 2013, we identified NDM-1-producing Escherichia coli and Enterobacter hormaechei strains from a single rectal swab sample from a patient hospitalized in Rio de Janeiro, Brazil, who had no history of travel abroad. Complete DNA sequencing using the Illumina platform and annotation of the two plasmids harboring the blaNDM-1 gene, one from each strain, showed that they belonged to incompatibility groups IncFIIK and IncX3 and harbored a novel transposon named Tn3000. Similar genetic structures have been identified among other isolates in Brazil but also on plasmids from other continents. Our findings suggest that the blaNDM-1 gene may be transmitted by Tn3000 in different parts of the world.

Supramolecular cationic assemblies against multidrug-resistant microorganisms: activity and mechanism of action.

The growing challenge of antimicrobial resistance to antibiotics requires novel synthetic drugs or new formulations for old drugs. Here, cationic nanostructured particles (NPs) self-assembled from cationic bilayer fragments and polyelectrolytes are tested against four multidrug-resistant (MDR) strains of clinical importance. The non-hemolytic poly(diallyldimethylammonium) chloride (PDDA) polymer as the outer NP layer shows a remarkable activity against these organisms. The mechanism of cell death involves bacterial membrane lysis as determined from the leakage of inner phosphorylated compounds and possibly disassembly of the NP with the appearance of multilayered fibers made of the NP components and the biopolymers withdrawn from the cell wall. The NPs display broad-spectrum activity against MDR microorganisms, including Gram-negative and Gram-positive bacteria and yeast.

Complete nucleotide sequences of two blaKPC-2-bearing IncN Plasmids isolated from sequence type 442 Klebsiella pneumoniae clinical strains four years apart.

We sequenced the oldest blaKPC-2-bearing plasmid isolated in Brazil and another plasmid also carried by a Klebsiella pneumoniae strain of sequence type 442 (ST442), isolated 52 months later. Both plasmids present an IncN backbone and few acquired regions. Because the 2005 plasmid presented deletions and a truncated gene within Tn4401b compared to the 2009 plasmid, we can thus infer that IncN blaKPC-2-bearing plasmids pFCF1305 and pFCF3SP had a common ancestor circulating in Brazil prior to May 2005.

Utility of realistic microscopy-based cell models in simulation studies of nanoparticle-enhanced photon radiotherapy.

To enhance the effect of radiation on the tumor without increasing the dose to the patient, the combination of high-Z nanoparticles with radiotherapy has been proposed. In this work, we investigate the effects of the physical parameters of nanoparticles (NPs) on the Dose Enhancement Factor (DEF), and on the Sensitive Enhancement Ratio (SER) by applying a version of the Linear Quadratic Model. A method for constructing voxelized realistic cell geometries in Monte Carlo simulations from confocal microscopy images was developed and applied to Gliobastoma Multiforme cell lines (U87 and U373). The comparison of simulations with realistic geometry and spherical geometry shows that there is significant impact on the survival curves obtained for the same irradiation conditions. Using this model, the DEF and the SER are determined as a function of the concentration, size and distribution of gold nanoparticles within the cell. For small NPs,dAuNP= 10 nm, no clear trend in the DEF and SER was observed when the number of NPs within the cell increases. Experimentally, the variable number of NPs measured inside the U373 cells (ranging between 1.48 × 105and 1.19 × 106) also did not influence much the observed cell survival upon irradiation of the cells with a Co-60 source. The same lack of trend is obtained when the Au content in the cell is kept constant, 0.897 mg/g, but the size of the NPs is changed. However, if the number of NPs is kept constant (7.91 × 105) and the size changes, there is a critical diameter above which the dose effect increases significantly. Using the realistic geometries, it was verified that the key parameter for the DEF and the SER enhancement is the volume fraction of Au in the cell, with NP size being a more important parameter than the number of NPs.

In vitro activity of ozenoxacin against Staphylococcus aureus and Streptococcus pyogenes clinical isolates recovered in a worldwide multicentre study (2020-2022).

Objectives: We performed a multicentre study (2020-2022) to compare the in vitro activity of ozenoxacin and comparator agents against Staphylococcus aureus and Streptococcus pyogenes clinical isolates from skin and soft-tissue infections (SSTI). Methods: A total of 1725 isolates (1454 S. aureus and 271 S. pyogenes) were collected in 10 centres from eight countries between January 2020 and December 2022. Antimicrobial susceptibility testing was determined (microdilution-SENSITITRE). Results were interpreted following European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2023 (clinical breakpoints, ECOFF) and CLSI criteria. Results: Ozenoxacin exhibited high in vitro activity against S. aureus (MIC50/90 = 0.002/0.12 mg/L) and S. pyogenes (MIC50/90 = 0.015/0.03 mg/L), inhibiting 99% of the isolates at MIC ≤ 0.5 mg/L and at MIC ≤ 0.06, respectively. The most active comparators against S. aureus were retapamulin (MIC90 = 0.12 mg/L), fusidic acid (MIC90 = 0.25 mg/L) and mupirocin (MIC90 = 0.5 mg/L); and against S. pyogenes were retapamulin (MIC90 = 0.03 mg/L), clindamycin (MIC90 = 0.12 mg/L) and mupirocin (MIC90 = 0.25 mg/L). Ciprofloxacin and methicillin resistant rates for S. aureus were 31.3% (455/1454) and 41% (598/1454), respectively. Additionally, 62% (373/598) of the MRSA were also ciprofloxacin non-susceptible, whereas only 10% (23/271) of the MSSA were ciprofloxacin resistant. Ozenoxacin was more active against ciprofloxacin-susceptible S. aureus than against ciprofloxacin-resistant isolates, and showed a slightly higher MIC in MRSA isolates than in MSSA. However, ozenoxacin activity was comparable in both ciprofloxacin-resistant MSSA and MRSA subsets. On the other hand, ozenoxacin had similar activity in ciprofloxacin-susceptible and resistant S. pyogenes isolates. Conclusions: Ozenoxacin is a potent antimicrobial agent of topic use against Gram-positive bacteria causing SSTI, including MRSA isolates non-susceptible to ciprofloxacin.

Impact of Caffeine Intake Strategies on Heart Rate Variability during Post-Exercise Recovery: A Systematic Review and Meta-Analysis.

OBJECTIVES: The objective of this systematic review and meta-analysis is to evaluate the influence of caffeine (CAF) intake strategies, taking into account their form, timing, and dosage, on heart rate variability (HRV) indices in the post-exercise recovery period. METHODS: The meta-analysis adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and is registered in the PROSPERO database (CRD42023425885). A comprehensive literature search was carried out across MEDLINE, Web of Science, LILACS, and SCOPUS, concluding in May 2023. We concentrated on randomized clinical trials comparing CAF supplementation effects to placebo on HRV indices post-exercise in active adults aged 18 and above. The primary endpoint was the assessment of HRV indices, measured both prior to and following exercise. RESULTS: Of the 10 studies included, 7 were used for the meta-analysis, and all contributed to the systematic review. The research explored a variety of CAF strategies, spanning different forms (capsule, drink, gum), times (10, 45, 60 min) and doses (2.1 to 6.0 mg/kg). The outcomes revealed no substantial variations between the placebo and CAF conditions in terms of both the square root of the average of successive squared differences between adjacent RR intervals (RMSSD) (standardized mean difference (SMD) -0.03, 95% CI -0.265 to 0.197, p=0.77) and high frequency (HF) index (SMD -0.061, 95% CI -0.272 to 0.150, p=0.57). Furthermore, metaregression analysis, employing a fixed-effects model and accounting for the administered CAF doses, revealed no significant correlation between caffeine doses and HRV indices (p>0.05). CONCLUSION: In conclusion, there is moderate-certainty evidence suggesting that different CAF intake strategies, encompassing aspects such as form, time, and dose, do not have a significant impact on HRV indices recovery post-exercise (i.e., vagal modulation).

Emergence of zoonotic sporotrichosis in Brazil: a genomic epidemiology study.

BACKGROUND: Zoonotic sporotrichosis is a neglected fungal disease, whereby outbreaks are primarily driven by Sporothrix brasiliensis and linked to cat-to-human transmission. To understand the emergence and spread of sporotrichosis in Brazil, the epicentre of the current epidemic in South America, we aimed to conduct whole-genome sequencing (WGS) to describe the genomic epidemiology. METHODS: In this genomic epidemiology study, we included Sporothrix spp isolates from sporotrichosis cases from Brazil, Colombia, and the USA. We conducted WGS using Illumina NovaSeq on isolates collected by three laboratories in Brazil from humans and cats with sporotrichosis between 2013 and 2022. All isolates that were confirmed to be Sporothrix genus by internal transcribed spacer or beta-tubulin PCR sequencing were included in this study. We downloaded eight Sporothrix genome sequences from the National Center for Biotechnology Information (six from Brazil, two from Colombia). Three Sporothrix spp genome sequences from the USA were generated by the US Centers for Disease Control and Prevention as part of this study. We did phylogenetic analyses and correlated geographical and temporal case distribution with genotypic features of Sporothrix spp isolates. FINDINGS: 72 Sporothrix spp isolates from 55 human and 17 animal sporotrichosis cases were included: 67 (93%) were from Brazil, two (3%) from Colombia, and three (4%) from the USA. Cases spanned from 1999 to 2022. Most (61 [85%]) isolates were S brasiliensis, and all were reported from Brazil. Ten (14%) were Sporothrix schenckii and were reported from Brazil, USA, and Colombia. For S schenckii isolates, two distinct clades were observed wherein isolates clustered by geography. For S brasiliensis isolates, five clades separated by more than 100 000 single-nucleotide polymorphisms were observed. Among the five S brasiliensis clades, clades A and C contained isolates from both human and cat cases, and clade A contained isolates from six different states in Brazil. Compared with S brasiliensis isolates, larger genetic diversity was observed among S schenckii isolates from animal and human cases within a clade. INTERPRETATION: Our results suggest that the ongoing epidemic driven by S brasiliensis in Brazil represents several, independent emergence events followed by animal-to-animal and animal-to human transmission within and between Brazilian states. These results describe how S brasiliensis can emerge and spread within a country. FUNDING: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil; the São Paulo Research Foundation; Productivity in Research fellowships by the National Council for Scientific and Technological Development, and Ministry of Science and Technology of Brazil.

Large hospital-wide outbreak of Paenibacillus spp pseudobacteremia associated with contaminated nonsterile gloves.

We report a large, hospital-wide outbreak of pseudobacteremia by Paenibacillus spp. In total, 139 patients presented at least 1 positive blood culture during a 13-month period. Microbiological experiments indicated that contaminated nonsterile gloves were associated with the pseudobacteremia episodes. The outbreak was resolved by discontinuing the use of the involved brand.