Purpose
Few series describe the clinical spectrum of
Fusobacterium
spp. infections. Among them, fewer discuss
F. nucleatum
, even though there are many clinical cases.
Methods
We performed a ...retrospective study over 8 years (from 2007 to 2014) in Limoges University Hospital, France, to assess clinical and bacteriological aspects of infections due to
F. nucleatum
.
Results
Eighty-one patients with
F. nucleatum
positive cultures were included in this study, irrespective of sample origin. Abscesses (
n
= 43), bacteraemia (
n
= 18) and bone infections (
n
= 8) were the most common types of infections, Abscesses were found in various organs (mostly skin, brain, pleura, liver). Co-morbidities were found in 38 patients (47 %) with neoplasia, diabetes, and alcoholism and history of smoking. There were more neoplasms in patients with bacteraemia than in patients with abscesses (
p
= 0.007). In 51 cases (65.4 %), infection was polymicrobial, either during bacteraemia or abscesses. Main associations were with
Streptococcus
spp.,
Peptostreptococcus
spp. and/or
Prevotella
spp. The sources of infection, when found, were either dental or gastrointestinal. All isolates were susceptible to penicillin, clindamycin and metronidazole.
Conclusions
Infections involving
F. nucleatum
are uncommon and potentially severe, with many abscesses requiring surgery. Bacteraemia was mainly associated with co-morbidities such as cancer. Polymicrobial infections were very common and there is probably interaction and/or synergy between
F. nucleatum
and some other commensal bacteria to cause infections and abscesses.
Objectives Integrons are bacterial genetic elements that can capture and express genes contained in mobile cassettes. Integrons have been described worldwide in Gram-negative bacteria and are a ...marker of antibiotic resistance. We developed a specific and sensitive Taqman® probe-based real-time PCR method with three different primer–probe pairs for simultaneous detection of the three main classes of integron. Methods Sensitivity was assessed by testing mixtures of the three targets (intI integrase genes of each integron class) ranging from 10 to 108 copies. Specificity was determined with a panel of integron-containing and integron-free control strains. The method was then applied to clinical samples. Results The PCR method was specific and had a sensitivity of 102 copies for all three genes, regardless of their respective quantities. The method was quantitative from 103 to 107 copies, and was able to detect integrons directly in biological samples. Conclusions We have developed a rapid, quantitative, specific and sensitive method that could prove useful for initial screening of Gram-negative isolates, or clinical samples, for likely multidrug resistance.
Abstract In Enterobacterales, the most common carbapenemases are Ambler’s class A (KPC-like), class B (NDM-, VIM- or IMP-like) or class D (OXA-48-like) enzymes. This study describes the ...characterization of twenty-four OXA-23 or OXA-58 producing- Proteus mirabilis isolates recovered from human and veterinary samples from France and Belgium. Twenty-two P. mirabilis isolates producing either OXA-23 (n = 21) or OXA-58 (n = 1), collected between 2013 and 2018, as well as 2 reference strains isolated in 1996 and 2015 were fully sequenced. Phylogenetic analysis revealed that 22 of the 24 isolates, including the isolate from 1996, belonged to a single lineage that has disseminated in humans and animals over a long period of time. The bla OXA-23 gene was located on the chromosome and was part of a composite transposon, Tn 6703 , bracketed by two copies of IS 15∆II . Sequencing using Pacbio long read technology of OXA-23-producing P. mirabilis VAC allowed the assembly of a 55.5-kb structure encompassing the bla OXA-23 gene in that isolate. By contrast to the bla OXA-23 genes, the bla OXA-58 gene of P. mirabilis CNR20130297 was identified on a 6-kb plasmid. The acquisition of the bla OXA-58 gene on this plasmid involved XerC-XerD recombinases. Our results suggest that a major clone of OXA-23-producing P. mirabilis is circulating in France and Belgium since 1996.
Among the geological features revealed by the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) mission on the surface of Mercury, hollows are the most surprising and least ...understood. Possibly related to volatile components, hollows are small depressions, surrounded by bright halos and are not observed on any other surfaces in our solar system. Previous analysis of multispectral data obtained by Mercury Dual Imaging System (MDIS) has shown that some hollows have weak spectral absorption features centered at around 600 nm. In this work, we analyzed four hollows with observations acquired by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on board MESSENGER with more than 230 spectral channels from the near‐ultraviolet to the near‐infrared. Unlike previous MDIS multispectral data, the MASCS reflectance spectra exhibit no absorption features in the MDIS wavelength range. However, we found that hollows have unique spectral properties in the near‐ultraviolet, with a spectral curvature between 300 and 600 nm that is distinctly different from other geological units. Moreover, we used MASCS observations with the best available spatial resolution (<0.5 km/pixel) to analyze both parts of a hollow: the flat floor and the surrounding halo. Our results support the hypothesis that hollows form by a sublimation process and scarp retreat.
Plain Language Summary
The MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) mission highlighted several geological terrains on Mercury's surface. Among the unexpected discoveries are small bright depressions, named hollows. Often found within impact craters, hollows have irregular shapes, flat floors, and are surrounded by bright halos. Hollows are still poorly understood and their formation remains a mystery for the scientific community. Using observations made by the spectrometer onboard the MESSENGER probe, we show for the first time that the spectra of hollows exhibit unique reflectance properties at near‐ultraviolet to visible wavelengths, which spectrally distinguishes them from other geological terrains. Moreover, the most detailed observations show that their flat floors have different spectral characteristics from the bright halos. Our results provide new knowledge about their formation, nature, and differences from other geological terrains and is consistent with them forming from sublimation processes.
Key Points
Hollows have unique spectral properties in the near‐ultraviolet
The reflectance spectra of hollows have a pronounced curvature between 300 and 600 nm
Eminescu impact crater hollows are seen to grow via scarp retreat
Ventilator-associated pneumonia (VAP) is the most common infection in critically ill patients. Initial antibiotic therapy is often broad spectrum, which promotes antibiotic resistance so new ...techniques are under investigation to obtain early microbiological identification and quantification. This trial compares the performance of a new real-time quantitative molecular-based method with conventional culture in patients with suspected VAP. Patients with suspected VAP who were ventilated for at least 48 h were eligible. An endotracheal aspirate (ETA) and a bronchoalveolar lavage (BAL) were performed at each suspected VAP episode. Both samples were analysed by conventional culture and molecular analysis. For the latter, bacterial DNA was extracted from each sample and real-time PCR were run. In all, 120 patients were finally included; 76% (91) were men; median age was 65 years, and clinical pulmonary infection score was ≥6 for 73.5% (86) of patients. A total of 120 BAL and 103 ETA could be processed and culture results above the agreed threshold were obtained for 75.0% (90/120) of BAL and 60.2% (62/103) of ETA. The main isolated bacteria were Staphylococcus aureus, Pseudomonas aeruginosa and Haemophilus influenzae. Performance was 89.2% (83.2%–93.6%) sensitivity and 97.1% (96.1%–97.9%) specificity for BAL samples and 71.8% (61.0%–81.0%) sensitivity and 96.6% (95.4%–97.5%) specificity for ETA samples when the molecular biology method was compared with conventional culture method (chosen as reference standard). This new molecular method can provide reliable quantitative microbiological data and is highly specific with good sensitivity for common pathogens involved in VAP.
Hospital effluents are involved in dissemination of antibiotic-resistant integrons. We describe here a new class 3 integron, In3-5, detected in an Enterobacter cloacae isolate retrieved from a random ...French hospital effluent sample collected in 2009. In3-5 carries two gene cassettes: the new blaOXA-256 and an aac(6′)-Ib variant, respectively conferring resistance to β-lactams and aminoglycosides. In3-5 is located on an IncQ-like backbone plasmid. Class 3 integrons could thus be involved in the dissemination of antibiotic resistance in both clinical settings and the environment, and could participate in the exchange of antibiotic-resistance genes between these two ecosystems.
•Viridans group Streptococci is the most common Streptococci involved in infective endocarditis (IE).•Minimum inhibitory concentration (MIC) for amoxicillin between 0.25 and 2 mg/L is associated with ...mortality.•Cardiac surgery for IE is the only protective factor.
A variety of microorganisms can cause infective endocarditis (IE), with Staphylococci and Streptococci accounting for the majority of cases. Streptococci are a common cause of community-acquired IE but few studies have focused on this subgroup of endocarditis.
A retrospective multicentre study was conducted between 2012 and 2017 in 12 hospital centres in France. Data were extracted from the local diagnosis-related group database and matched with microbiological results. After identification, the records were retrospectively analysed.
A total of 414 patients with streptococcal endocarditis were included. The patients were predominantly male (72.8%) and the median age was 73.2 years (interquartile range IQR 61.3-80.9). The majority of patients (70.6%) had native valve endocarditis. Embolic complications were seen in 38.8% of patients. Viridans group Streptococci (VGS) and bovis-equinus group Streptococci (BGS) accounted for 52.4% and 34.5% of isolated strains, respectively. Minimum inhibitory concentrations (MICs) of amoxicillin were <0.125, 0.125-2 and >2 mg/L for 59.6%, 27% and 1% of isolates, respectively. In-hospital mortality for patients with Streptococci-related IE was 17.8%. In multivariate analysis, the only factor associated with in-hospital mortality was MIC for amoxicillin between 0.25 and 2 mg/L (P = 0.04; OR = 2.23 95% confidence interval (CI) 1.03-4.88) whereas performance of cardiac surgery for IE was a protective factor (P = 0.001, OR = 0.23 95% CI 0.1-0.56).
IE remains a serious and deadly disease despite recent advances in diagnosis and treatment. Adaptation of antibiotic doses to MICs for amoxicillin and surgery may improve patient outcome.
Explosive volcanism on the surface of planet Mercury is visible through the pyroclastic deposits that surround morphologic features often identified as the vent. Those deposits are known as faculae. ...The understanding of explosive volcanism provides important information on Mercury's geological, thermal, and volcanic history. Observations by the MESSENGER spacecraft are used to analyze in detail the spectral properties of 14 selected faculae with the aim of understanding their chemical and physical properties. Scientific observations obtained by the MASCS instrument are particularly suitable for this task, although their observational and geometrical constraints limit definitive conclusions. Nonetheless, spectral properties in the visible, ultraviolet and near‐infrared indicate that the selected faculae are probably larger than visible in images solely. Spectral parameters provide a means to isolate Mercury's pyroclastic deposits with respect to Mercury's average spectral behavior. The similar spectral behavior of the visible, ultraviolet and near‐infrared domains suggests that the amount of mixing of pyroclastic materials with the underlying material, the differences in grain sizes between and inside the faculae, and the presence of opaque/mineral phases, could play significant roles in the spectral properties observed. Observations by the BepiColombo mission in nadir configuration covering a large range of phase angles will be highly complementary to the MESSENGER observations.
Plain Language Summary
The presence of volcanism on Mercury has been confirmed from observations taken by the NASA MESSENGER mission in 2011. As on Earth, various styles of volcanism have been detected; explosive volcanism which involves a low volume of lava and high volume of gas, and effusive volcanism, which is richer in lava and poorer in gas. Using observations in the near‐infrared and visible spectral domain, this analysis aims at better characterizing the physical and chemical properties of the deposits resulting from explosive volcanism. In this manuscript, it is shown that the scale of deposits resulting from explosive volcanism has been underestimated, which cascades to a potential underestimation of the quantity of gas present in the interior of Mercury through its history. Additionally, it is shown that the amount of mixing of pyroclastic materials with the underlying material, the differences in grain sizes between and inside the faculae, and the presence of opaque/mineral phases, could play significant roles in the spectral properties observed in near infrared and visible spectral domain. Unfortunately, the limitations in the measurements from MESSENGER complicate the exploration of physical and chemical properties. These issues will be better explored with the BepiColombo mission, the next mission to explore the surface of Mercury.
Key Points
Variations in spectral properties are correlated with the distance from the source
Grain size, regolith mixing, and/or the presence of an opaque/mineral are possible controlling factors in the spectral variability observed
Faculae (e.g., Bitin, Agwo, Orm) have a larger spatial extent than image data alone suggest
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