The YAP1-TEAD axis promotes autophagy against intracellular Staphylococcus aureus in vitro

Previously considered as an exclusive extracellular bacterium, Staphylococcus aureus has been shown to be able to invade many cells in vitro and in humans. Once inside the host cell, both cytosolic and endosome-associated S. aureus strongly induce macroautophagy/autophagy. Whether autophagy fosters S. aureus intracellular survival or clearance remains unclear. The YAP1-TEAD axis regulates the expression of target genes controlling the cell fate (e.g., proliferation, migration, cell cycle …). Growing evidence indicates that YAP1-TEAD also regulates autophagy and lysosomal pathways. Recently we showed that the YAP1-TEAD axis promotes autophagy and lysosome biogenesis to restrict S. aureus intracellular replication. We also discovered that the C3 exoenzyme-like EDIN-B toxin produced by the pathogenic S. aureus ST80 strain inhibits YAP1 nuclear translocation resulting in a strong increase of intracellular S. aureus burden.

Prospective Evaluation of the BD MAX StaphSR Assay for the Screening of Methicillin-Susceptible and -Resistant Staphylococcus aureus from Nasal Swabs Taken in Intensive Care Unit Patients

Screening patients for S. aureus nasal carriage has proved effective in preventing cross-contamination and endogenous infection with this bacterium. The aim of this study was to assess the performance of the BD MAX StaphSR assay with liquid Amies elution swabs, taken during routine care of intensive care unit patients. Direct and pre-enriched cultures were used as reference methods to screen for S. aureus and methicillin-resistant S. aureus (MRSA). Discrepant results between the BD MAX StaphSR assay and cultures were resolved by using the Xpert SA Nasal Complete assay. A total of 607 nasal swabs taken from 409 patients were included in this study. Compared to culture methods, the sensitivity and specificity of the BD MAX StaphSR assay were 92.5% and 91.7% for S. aureus screening, and 94.7% and 98.3% for MRSA screening, respectively. In 52 (8.6%) specimens, there was a discrepancy between the results of cultures and the BD MAX StaphSR assay, including 13 (25%) where the results of the BD MAX StaphSR assay were confirmed by the Xpert SA Nasal Complete test. This prospective study showed that the BD MAX StaphSR assay is reliable for S. aureus and MRSA detection from nasal samples taken with liquid Amies elution swabs.

Filtration efficiency of medical and community face masks using viral and bacterial bioaerosols

Face masks are often recommended in community settings to prevent the airborne transmission of respiratory viruses or bacteria. Our first objective was to develop an experimental bench to assess the viral filtration efficiency (VFE) of a mask with a methodology similar to the normative measurement of bacterial filtration efficiency (BFE) used to determine the filtration performance of medical masks. Then, using three categories of masks of increasing filtration quality (two types of community masks and one type of medical mask), filtration performances measured ranged from 61.4 to 98.8% of BFE and from 65.5 to 99.2% of VFE. A strong correlation (r = 0.983) between bacterial and viral filtration efficiency was observed for all types of masks and for the same droplets size in the 2-3 µm range. This result confirms the relevance of the EN14189:2019 standard using bacterial bioaerosols to evaluate mask filtration, to also extrapolate mask performances whatever their filtration quality against viral bioaerosols. Indeed, it appears that the filtration efficiency of masks (for micrometer droplet sizes and low bioaerosol exposure times) depends mainly on the size of the airborne droplet, rather than on the size of the infectious agent contained in that droplet.

Staphylococcus aureus nasal colonization level and intracellular reservoir: a prospective cohort study

Staphylococcus aureus is a major pathogen in humans. The nasal vestibule is considered as the main reservoir of S. aureus. However, even though the nasal cavity may also be colonized by S. aureus, the relationships between the two sites are still unclear. We conducted a prospective study in humans to assess the S. aureus colonization profiles in the vestibule and nasal cavity, and to investigate the presence of intracellular S. aureus in the two sites. Patients undergoing ear, nose, and throat surgery were swabbed during endoscopy to determine S. aureus nasal load, genotype, and presence of intracellular S. aureus. Among per-operative samples from 90 patients, the prevalence of S. aureus carriage was 32.2% and 33.3% in the vestibule and the nasal cavity, respectively. The mean S. aureus load was 4.10 and 4.25 log₁₀ CFU/swab for the nasal vestibule and nasal cavity, respectively (P > 0.05). Genotyping of S. aureus revealed that all nasal strains isolated from a given individual belong to the same clonal complex and spa-type. An intracellular carriage was observed in 5.6% of the patients, all of whom exhibited a S. aureus vestibule load higher than 3 log₁₀ CFU/swab. An intracellular niche was observed in the vestibule as well as in the nasal cavity. In conclusion, the nasal cavity was also found to be a major site of S. aureus carriage in humans and should draw attention when studying host-pathogen interactions related to the risk of infection associated with colonization.

Evaluation of the BL-RED (Beta-Lactamase Rapid Electrochemical Detection) test for the rapid detection of resistance to third-generation cephalosporins in Enterobacteriaceae

The sensitivity of NG-test CTX-M Multi assay and BL-RED test incubated 10 min for the detection of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae was 80.6% and 90.3% respectively. Using an extended 60 min incubation with the BL-RED test, its sensitivity was increased to 100% and 60.9% for ESBL-producing and cephalosporinase-overexpressing Enterobacteriaceae respectively.

Key Role of Staphylococcal Fibronectin-Binding Proteins During the Initial Stage of Staphylococcus aureus Keratitis in Humans

Objectives

Staphylococcus aureus is one of the main causes of bacterial keratitis in humans. This study was aimed at investigating the mechanisms of S. aureus adhesion to the human corneal epithelium involved during the initial stage of infectious keratitis.

Methods

Human corneas stored in a specific active storage machine that restores a normal pluristratified epithelium were used to assess S. aureus adhesion level to intact and injured tissues using immunostaining. S. aureus adhesion to immobilized fibronectin was measured in microtiter plate. Internalization of S. aureus clinical isolates recovered from keratitis was assessed on human corneal epithelial HCE-2 cells.

Results

Superficial corneal injury unmasked fibronectin molecules expressed within the human corneal epithelium. S. aureus adhesion level was increased by 117-fold in the area of injured epithelium (p < 0.0001). The deletion of staphylococcal fnbA/B genes decreased by 71% the adhesion level to immobilized fibronectin (p < 0.001). The deletion of fnbA/B genes and the incubation of the corneas with anti-fibronectin blocking antibodies prior to the infection significantly reduced the S. aureus adhesion level to injured corneal epithelium (p < 0.001). Finally, S. aureus clinical isolates triggered its internalization in human corneal epithelial cells as efficiently as the 8325-4 wt.

Conclusion

S. aureus was almost unable to bind the intact corneal epithelium, whereas a superficial epithelial injury of the corneal epithelium strongly increased S. aureus adhesion, which is mainly driven by the interaction between staphylococcal fibronectin-binding proteins and unmasked fibronectin molecules located underneath the most superficial layer of the corneal epithelium.

Evaluation of in vitro activity of copper gluconate against SARS-CoV-2 using confocal microscopy-based high content screening

CONTEXT

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that emerged late in 2019 is the etiologic agent of coronavirus disease 2019 (Covid-19). There is an urgent need to develop curative and preventive therapeutics to limit the current pandemic and to prevent the re-emergence of Covid-19. This study aimed to assess the in vitro activity of copper gluconate against SARS-CoV-2.

METHODS

Vero E6 cells were cultured with or without copper gluconate 18-24 hours before infection. Cells were infected with a recombinant GFP expressing SARS-CoV-2. Cells were infected with a recombinant GFP expressing SARS-CoV-2. Infected cells were incubated in fresh medium containing varying concentration of copper gluconate (supplemented with bovine serum albumin or not) for an additional 48 -h period. The infection level was measured by the confocal microscopy-based high content screening method. The cell viability in presence of copper gluconate was assessed by XTT and propidium iodide assays.

RESULTS

The viability of Vero E6 cells exposed to copper gluconate up to 200 μM was found to be similar to that of unexposed cells, but it dropped below 70 % with 400 μM of this agent after 72 h of continuous exposure. The infection rate was 23.8 %, 18.9 %, 20.6 %, 6.9 %, 5.3 % and 5.2 % in cells treated prior infection with 0, 2, 10, 25, 50 and 100 μM of copper gluconate respectively. As compared to untreated cells, the number of infected cells was reduced by 71 %, 77 %, and 78 % with 25, 50, and 100 μM of copper gluconate respectively (p < 0.05). In cells treated only post-infection, the rate of infection dropped by 73 % with 100 μM of copper gluconate (p < 0.05). However, the antiviral activity of copper gluconate was abolished by the addition of bovine serum albumin.

CONCLUSION

Copper gluconate was found to mitigate SARS-CoV-2 infection in Vero E6 cells but this effect was abolished by albumin, which suggests that copper will not retain its activity in serum. Furthers studies are needed to investigate whether copper gluconate could be of benefit in mucosal administration such as mouthwash, nasal spray or aerosols.

Improved Enzyme Protection Assay to Study Staphylococcus aureus Internalization and Intracellular Efficacy of Antimicrobial Compounds

Staphylococcus aureus expresses virulence factors to trigger its internalization into eukaryote cells and to survive inside different subcellular compartments. This paper describes an enzyme protection assay to study the extent of S. aureus internalization and its intracellular survival in adherent non-professional phagocytic cells (NPPCs) as well as the intracellular efficacy of antimicrobial compounds. NPPCs are grown in a multi-well plate until they reach 100% confluence. S. aureus cultures are grown overnight in cell culture medium. The bacterial suspension is diluted according to the number of cells per well to inoculate the cells at a controlled multiplicity of infection. Inoculated cells are incubated for 2 h to allow the bacteria to be internalized by the NPPCs, following which lysostaphin is added to the culture medium to selectively kill extracellular bacteria. Lysostaphin is present in the culture medium for the rest of the experiment. At this point, the infected cells could be incubated with antimicrobial compounds to assess their intracellular activities against S. aureus. Next, the cells are washed three times to remove the drugs, and intracellular S. aureus load is then quantified by culturing on agar plates. Alternatively, for studying staphylococcal virulence factors involved in intracellular survival and cell toxicity, lysostaphin could be inactivated with proteinase K to eliminate the need for washing steps. This tip improves the reliability of the intracellular bacterial load quantification, especially if cells tend to detach from the culture plate when they become heavily infected because of the multiplication of intracellular S. aureus. These protocols can be used with virtually all types of adherent NPPCs and with 3D cell culture models such as organoids.

The properties of hot household hygroscopic materials and their potential use for non-medical facemask decontamination

The widespread use of facemasks throughout the population is recommended by the WHO to reduce transmission of the SARS-CoV-2 virus. As some regions of the world are facing mask shortages, reuse may be necessary. However, used masks are considered as a potential hazard that may spread and transmit disease if they are not decontaminated correctly and systematically before reuse. As a result, the inappropriate decontamination practices that are commonly witnessed in the general public are challenging management of the epidemic at a large scale. To achieve public acceptance and implementation, decontamination procedures need to be low-cost and simple. We propose the use of hot hygroscopic materials to decontaminate non-medical facemasks in household settings. We report on the inactivation of a viral load on a facial mask exposed to hot hygroscopic materials for 15 minutes. As opposed to recent academic studies whereby decontamination is achieved by maintaining heat and humidity above a given value, a more flexible procedure is proposed here using a slow decaying pattern, which is both effective and easier to implement, suggesting straightforward public deployment and hence reliable implementation by the population.

Evaluation of effectiveness and compliance with the mupirocin nasal ointment part of Staphylococcus aureus decolonization in real life using UPLC-MS/MS mupirocin quantification

BACKGROUND

Preoperative decolonization is recommended in Staphylococcus aureus nasal carriers scheduled for cardiac surgery. We aimed to evaluate the effectiveness of and compliance with mupirocin use in nasal S. aureus carriers in a real-life setting.

METHODS

Prospective study including consecutive patients scheduled for cardiac surgery screened for S. aureus nasal carriage at preoperative consultation. Carriers were prescribed mupirocin nasal ointment, chlorhexidine shower and mouthwash. Effectiveness of decolonization was evaluated with a postoperative nasal sample. Compliance was evaluated objectively by determination of nasal mupirocin concentration using UPLC-MS/MS and self-reported by questionnaire.

RESULTS

Over 10 months, 361 patients were included, 286 had preoperative screening, 75 (26.2%) were S. aureus nasal carriers and 19 of them (25.3%) failed to be effectively decolonized. No resistance to mupirocin was documented. Preoperative and postoperative strains were identical in all cases. Declared good compliance was associated with decolonization success (OR = 24; 95% CI 4-143, P < 0.0001). Mupirocin detection was significantly associated with the level of compliance. Mupirocin was detected in 52.2% (24/46) of patients effectively decolonized and in 12.5% (2/16) of patients with decolonization failure (P < 0.01). In 2/19 patients, failure of decolonization was not associated with a compliance issue. Postoperative carriage was associated with an increased risk of S. aureus infection (OR = 9.8; 95% CI 1.8-53, P < 0.01).

CONCLUSIONS

In real life, decolonization is not always effective, hence there is a persisting risk of S. aureus endogenous infection. Mupirocin concentration measurement may help to understand compliance issues and failures in decolonization.

New insights into the standard method of assessing bacterial filtration efficiency of medical face masks

Based on the current knowledge of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) transmission, wearing a mask has been recommended during the COVID-19 pandemic. Bacterial filtration efficiency (BFE) measurements enable designing and regulating medical masks to prevent bioaerosol dissemination; however, despite the simplicity of these measurements, several scientific questions remain unanswered regarding BFE tests. Here, we investigated (1) the impact of substituting 100-mm Petri dishes with 90-mm disposable Petri dishes, (2) the impact of colony-counting methods on the bioaerosol aerodynamic size, and (3) the impact of colony-counting methods on the total viable particle counts. We demonstrated that disposable 90-mm Petri dishes can be used to replace the 100-mm dishes. We also showed that an automatic high-resolution colony counter can be used to directly count viable particles on collection substrates and to measure the bioaerosol size parameters. Our results enable possible modernization of the outdated testing methods recommended in the US and European standards for BFE measurements. Specifically, use of a modernized colony counter should be clearly regulated and permitted to avoid the counting of positive holes. The median aerodynamic diameter appears to be the most relevant parameter for characterizing bioaerosol size.

Assessment of Respiratory Bacterial Coinfections Among Severe Acute Respiratory Syndrome Coronavirus 2-Positive Patients Hospitalized in Intensive Care Units Using Conventional Culture and BioFire, FilmArray Pneumonia Panel Plus Assay

Background

Approximately 15% of patients infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) present with severe forms of the disease and require hospitalization in intensive care units, which has been associated with high mortality rates. The prevalence of bacterial infections in these patients is not well established, and more data are needed to guide empiric antibiotic therapy and improve patient outcomes.

Methods

In this prospective multicenter study, we assessed bacterial coinfections identified in culture from 99 French patients infected by SARS-Cov-2 and hospitalized in intensive care units. We concomitantly evaluated an innovative molecular diagnostic technology technique, the BioFire, FilmArray Pneumonia Panel plus (FA-pneumo) assay, to identify these coinfections at an early stage, and its concordance with conventional culture.

Results

We showed that a bacterial coinfection was detected in 15% of patients based on conventional culture. Staphylococcus aureus and Haemophilus influenzae were the most prevalent pathogens. The sensitivity of FA-pneumo compared with culture was 100%. In contrast, the specificity varied between 88.4% and 100% according to the pathogen, and our results highlighted that 60.5% of bacterial targets reported using this assay were not recovered by culture; 76.9% of discordant results corresponded to bacteria belonging to commensal oral flora and/or reported with ≤10⁵ copies/mL bacterial nucleic acids.

Conclusions

Based on its excellent sensitivity, the FA-pneumo assay is useful to rule out bacterial coinfections in the context of severe SARS-CoV-2 infection and avoid the inappropriate prescription of antibiotics. However, positive tests should be interpreted carefully, taking into consideration deoxyribonucleic acid bacterial load and all clinical and biological signs.

Controlled Heat and Humidity-Based Treatment for the Reuse of Personal Protective Equipment: A Pragmatic Proof-of-Concept to Address the Mass Shortage of Surgical Masks and N95/FFP2 Respirators and to Prevent the SARS-CoV2 Transmission

Background: The coronavirus infectious disease-2019 (COVID-19) pandemic has led to an unprecedented shortage of healthcare resources, primarily personal protective equipment like surgical masks, and N95/filtering face piece type 2 (FFP2) respirators.

Objective: Reuse of surgical masks and N95/FFP2 respirators may circumvent the supply chain constraints and thus overcome mass shortage. Methods, design, setting, and measurement: Herein, we tested the effects of dry- and moist-air controlled heating treatment on structure and chemical integrity, decontamination yield, and filtration performance of surgical masks and FFP2 respirators.

Results: We found that treatment in a climate chamber at 70°C during 1 h with 75% humidity rate was adequate for enabling substantial decontamination of both respiratory viruses, oropharyngeal bacteria, and model animal coronaviuses, while maintaining a satisfying filtering capacity.

Limitations: Further studies are now required to confirm the feasibility of the whole process during routine practice.

Conclusion: Our findings provide compelling evidence for the recycling of pre-used surgical masks and N95/FFP2 respirators in case of imminent mass shortfall.

Brief comparative evaluation of six open one-step RT-qPCR mastermixes for the detection of SARS-CoV-2 RNA using a Taqman probe

•

In case of virus emergence, laboratory-developed assays (LDA) should be urgently assessed.

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Recommended open one-step RT-qPCR reagents are rapidly on tension in case of pandemic.

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Five other reagents were shown to be used for SARS-CoV-2 RNA detection by LDA.

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This study can help laboratories to assess LDA for detecting emerging RNA viruses.

Background

Facing the emergence of a new RNA virus, clinical laboratories are often helpless in the case of a shortage of reagents recommended by Reference Centres.

Objectives

To compare five open one step RT-qPCR reagents to the SuperScript™ III Platinum™ One-Step qRT-PCR kit (Invitrogen) considered as the reference one in France at the beginning of the pandemic for detection of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in respiratory specimens by using a laboratory-developed assay targeting the viral RNA dependant RNA polymerase (RdRp) gene.

Study design

A total of 51 NUCLISENS easyMAG extracts from respiratory specimens was tested on ABI 7500 thermocycler with TaqMan Fast Virus 1-Step Master Mix (Applied Biosystems), Luna® Universal Probe One-Step RT-qPCR Kit (New England Biolabs), GoTaq® Probe 1- Step RT-qPCR System (Promega), LightCycler® Multiplex RNA Virus Master (Roche) and One-step PrimeScript RT-PCR kit (Takara). The CT values obtained using the 5 challenged reagents were compared to those obtained using the reference assay.

Results

The percentages of concordance were all above 95 %. When comparing the CT values of the 48 extracts exhibiting CT values < 35 obtained with the reference reagent, the results were similar between the reagents although the differences of CT values were quite dispersed.

Conclusions

All five reagents can be considered as alternative reagents to the reference for detecting SARS-CoV-2 RNA.

Ex vivo model of herpes simplex virus type I dendritic and geographic keratitis using a corneal active storage machine

BACKGROUND

Herpetic keratitis (HK) models using whole human corneas are essential for studying virus-host relationships, because of high species specificity and the role of interactions between corneal cell populations that cell culture cannot reproduce. Nevertheless, the two current corneal storage methods (hypothermia and organ culture (OC)) do not preserve corneas in good physiological condition, as they are characterized by epithelial abrasion, stromal oedema, and excessive endothelial mortality.

METHODS

To rehabilitate human corneas intended for scientific use, we used an active storage machine (ASM) that restores two physiological parameters that are essential for corneal homeostasis: intraocular pressure and storage medium renewal (21mmHg and 2.6 μL/min, respectively). ASM storage regenerates a normal multilayer epithelium in 2 weeks. We infected six pairs of corneas unsuitable for graft by inoculating the epithelium with herpes simplex virus type 1 (HSV-1), and compared each ASM-stored cornea with the other cornea stored in the same medium using the conventional OC method.

RESULTS

Only corneas in the ASM developed a dendritic (n = 3) or geographic (n = 2) epithelial ulcer reproducing typical HSV-1-induced clinical lesions. Corneas in OC showed only extensive desquamations. None of the uninfected controls showed epithelial damage. Histology, immunohistochemistry, transmission electron microscopy and polymerase chain reaction on corneal tissue confirmed infection in all cases (excluding negative controls).

CONCLUSIONS

The ASM provides an innovative ex vivo model of HK in whole human cornea that reproduces typical epithelial lesions.

Tick-Borne Encephalitis in Auvergne-Rhône-Alpes Region, France, 2017-2018

Three autochthonous cases of tick-borne encephalitis (TBE) acquired in rural areas of France where Lyme borreliosis, but not TBE, is endemic highlight the emergence of TBE in new areas. For patients with neurologic involvement who have been in regions where Ixodes ticks circulate, clinicians should test for TBE virus and other tickborne viruses.

Strategy using a new antigenic test for rapid diagnosis of Streptococcus pneumoniae infection in respiratory samples from children consulting at hospital

Background

Despite vaccination programs, Streptococcus pneumoniae remains among the main microorganisms involved in bacterial pneumonia, notably in terms of severity. The prognosis of pneumococcal infections is conditioned in part by the precocity of the diagnosis. The aim of this study was to evaluate the impact of a Rapid Diagnostic Test (RDT) targeting cell wall polysaccharide of Streptococcus pneumoniae and performed directly in respiratory samples, on the strategy of diagnosis of respiratory pneumococcal infections in children.

Results

Upper-respiratory tract samples from 196 children consulting at hospital for respiratory infection were tested for detecting S. pneumoniae using a newly-designed RDT (PneumoResp, Biospeedia), a semi-quantitative culture and two PCR assays. If positive on fluidized undiluted specimen, the RDT was repeated on 1:100-diluted sample. The RDT was found highly specific when tested on non-S. pneumoniae strains. By comparison to culture and PCR assays, the RDT on undiluted secretions exhibited a sensitivity (Se) and negative predictive value (NPV) of more than 98%. By comparison to criteria of S. pneumoniae pneumonia combining typical symptoms, X-ray image, and culture ≥10⁷ CFU/ml, the Se and NPV of RDT on diluted specimens were 100% in both cases.

Conclusions

In case of negative result, the excellent NPV of RDT on undiluted secretions allows excluding S. pneumoniae pneumonia. In case of positive result, the excellent sensitivity of RDT on diluted secretions for the diagnosis of S. pneumoniae pneumonia allows proposing a suitable antimicrobial treatment at day 0.

Intracellular activity of antimicrobial compounds used for Staphylococcus aureus nasal decolonization

Background

Staphylococcus aureus is able to invade mammalian cells during infection and was recently observed inside nasal mucosa of healthy carriers.

Objectives

To determine the intracellular activity of antimicrobial compounds used for decolonization procedures using a cell model mimicking S. aureus nasal epithelium invasion.

Patients and methods

HaCaT cells and human nasal epithelial cells (HNECs) recovered from nasal swabs of S. aureus carriers were visualized by confocal laser scanning microscopy to detect intracellular S. aureus cells. An HaCaT cell model, mimicking S. aureus internalization observed ex vivo in HNECs, was used to assess the intracellular activity against S. aureus of 21 antimicrobial compounds used for nasal decolonization, including mupirocin and chlorhexidine.

Results

HaCaT cells and HNECs were found to internalize S. aureus with the same focal pattern. Most antimicrobial compounds tested on HaCaT cells were shown to have weak activity against intracellular S. aureus. Some systemic antimicrobials, including fusidic acid, clindamycin, linezolid, minocycline, ciprofloxacin, moxifloxacin, rifampicin and levofloxacin, reduced S. aureus intracellular loads by 0.43-1.66 log cfu/106 cells compared with the control (P < 0.001). By contrast, mupirocin and chlorhexidine reduced the S. aureus intracellular load by 0.19 and 0.23 log cfu/106 cells, respectively.

Conclusions

These data indicate that most of the antimicrobial compounds used for nasal decolonization, including mupirocin and chlorhexidine, exhibit weak activity against intracellular S. aureus using the HaCaT cell model. This work emphasizes the need to better understand the role of the S. aureus intracellular reservoir during nasal colonization in order to improve decolonization procedures.

Interplay of nasal and rectal carriage of Staphylococcus aureus in intensive care unit patients

The aim of this study was to investigate the relationship between nasal and rectal Staphylococcus aureus carriage in intensive care unit (ICU) patients and the occurrence of ICU-acquired infections related to S. aureus carriage. Three hundred and ninety-five patients admitted in ICU were screened for S. aureus nasal and rectal carriages and followed to record S. aureus infections during their stay. S. aureus strains were genotyped by arbitrarily primed PCR, spa-typing, microarray and whole genome sequencing. At ICU admission, 112 of 363 (30.9%) patients carried S. aureus including 61 (16.8%) exclusive nasal carriers, 40 (11.0%) combined nasal and rectal carriers and 11 (3.0%) exclusive rectal carriers. The 152 S. aureus isolates from nasal and rectal swabs belonged to 19 clonal complexes (CCs). Patients colonized in both nose and rectum harboured different strains in at least 40% of cases according to arbitrarily primed PCR data. Nasal carriers of CC5 S. aureus had an increased risk of rectal carriage (RR = 1.85, P < .05). S. aureus nasal and rectal carriage was a risk factor of S. aureus ICU-acquired infection (RR = 4.04; 95%CI [1.38-11.76]). Incidence rates of endogenous ICU-acquired infections in exclusive nasal carriers, exclusive rectal carriers and in both nasal and rectal carriers were 0.08 (5/61), 0.09 (1/11) and 0.03 (1/40), respectively (p = 0.47). Rectal swabbing increased the detection of S. aureus carriage and revealed an important diversity of S. aureus strains in ICU patients. Further studies are needed to understand how S. aureus rectal carriage increases the risk of endogenous ICU-acquired infections.

Acute kidney injury in infective endocarditis: A retrospective analysis

BACKGROUND

Acute kidney injury (AKI) is associated with high case fatality in infective endocarditis (IE), but epidemiological data on the frequency of AKI during IE is scarce. We aimed to describe the frequency and risk factors for AKI during the course of IE using Kidney Disease: Improving Global Outcomes consensual criteria.

METHODS

Using the French hospital discharge database (French acronym PMSI), we retrospectively reviewed the charts of 112 patients presenting with a first episode of probable or definite IE between January 2010 and May 2015.

RESULTS

Seventy-seven patients (68.8%) developed AKI. In univariate analysis, risk factors for AKI were cardiac surgery for IE (n=29, 37.7% vs. n=4, 1.4%, P<0.0005), cardiac failure (n=29, 36.7% vs. n=1, 2.9%, P<0.0005), diabetes mellitus (n=14, 18.2% vs. n=1, 0.9%, P=0.034), and prosthetic valve IEs (n=24, 31.2% vs. n=4, 11.4%). No differences were observed for gentamicin exposure (n=57, 64% vs. n=32, 86.5%, P=0.286). Prosthetic valve IE, cardiac failure, and vancomycin exposure were independently associated with AKI with respective odds ratio of 5.49 (95% CI 1.92-17.9), 4.37 (95% CI 4.37-465.7), and 1.084 (1.084-16.2). Mean length of hospital stay was significantly longer in patients presenting with AKI than in controls (respectively 52.4±22.1 days vs. 39.6±12.6, P<0.005).

CONCLUSION

AKI is very frequent during IE, particularly in patients with prosthetic valve IE, cardiac failure, and those receiving vancomycin.

Community-Acquired Staphylococcus argenteus Sequence Type 2250 Bone and Joint Infection, France, 2017

We report a rare case of Staphylococcus argenteus bone and joint infection in a 9-year-old boy in France. His finger arthritis was complicated by osteitis 5 weeks later, which resulted in a secondary intervention. This case indicates the virulence of S. argenteus, an emerging pathogen whose clinical effects are poorly described.

HaCaT epithelial cells as an innovative novel model of rhinovirus infection and impact of clarithromycin treatment on infection kinetics

The in vitro propagation of human rhinoviruses (RVs) is difficult because only few continuous human cell lines are permissive to these agents. We propose an innovative model of epithelial cell infection using a non-transformed continuous keratinocyte line from human origin (HaCaT cells). After infection with RV-A13, RV-A16 or RV-A19, HaCaT cells produced infectious particles without showing any observable cytopathic effect and overexpressed ICAM-1 (intercellular adhesion molecule 1), the major entry receptor of RVs. Furthermore, the treatment of HaCaT cells with 10 µM clarithromycin reduced the viral titer by 93% and 60% during the first and second days following viral infection, respectively, probably by down-regulating ICAM-1 expression. This original model of epithelial cell infection by RV could be useful to study chronic viral infection and bacterium-virus interactions at the cell level. These results also suggest that clarithromycin may be evaluated for treating in vivo infections associating RV to a susceptible bacterium.

Staphylococcus aureus colonization and non-influenza respiratory viruses: Interactions and synergism mechanisms

Viral infections of the respiratory tract can be complicated by bacterial superinfection, resulting in a significantly longer duration of illness and even a fatal outcome. In this review, we focused on interactions between S. aureus and non-influenza viruses. Clinical data evidenced that rhinovirus infection may increase the S. aureus carriage load in humans and its spread. In children, respiratory syncytial virus infection is associated with S. aureus carriage. The mechanisms by which some non-influenza respiratory viruses predispose host cells to S. aureus superinfection can be summarized in three categories: i) modifying expression levels of cellular patterns involved in S. aureus adhesion and/or internalization, ii) inducing S. aureus invasion of epithelial cells due to the disruption of tight junctions, and iii) decreasing S. aureus clearance by altering the immune response. The comprehension of pathways involved in S. aureus-respiratory virus interactions may help developing new strategies of preventive and curative therapy.

Epidemiology and clinical relevance of Staphylococcus aureus intestinal carriage: a systematic review and meta-analysis

INTRODUCTION

Recent data highlight the importance of screening more than one site for improving the detection of S. aureus colonization. Intestinal carriage is frequently under-investigated and its clinical impact ought to be defined a better way. Areas covered: This review and meta-analysis provide an updated overview of prevalence, characteristics and clinical significance of S. aureus intestinal carriage in different populations, both for methicillin-susceptible and -resistant S. aureus strains. Expert commentary: Intestinal S. aureus carriage is documented with higher prevalence in children and in patients with S. aureus skin and soft tissue infections. This site of colonization was shown to be associated with a high risk of dissemination in the environment and with S. aureus infection. Intestinal carriage is frequently retrieved in nasal carriers, reflecting probably an association with a high bacterial load. Exclusive intestinal carriage present in one third of intestinal carriers can be associated with infection. Comparative genotyping analysis of different strains from nasal and extra-nasal sites of carriage, including the intestinal ones, in the same individuals, would allow a better comprehension of the pathophysiology of S. aureus endogenous infection. It could also permit to improve the prevention of these infections by decolonization of sites implicated in infection genesis.

Effect of a lotion containing the heat-treated probiotic strain Lactobacillus johnsonii NCC 533 on Staphylococcus aureus colonization in atopic dermatitis

Objective

Staphylococcus aureus dominates the skin microbiota in patients with atopic dermatitis (AD), with bacterial loads correlating with disease severity. The aim of this exploratory study was to investigate the effect of a cosmetic lotion containing heat-treated Lactobacillus johnsonii NCC 533 (HT La1) on S. aureus colonization in AD patients.

Methods

This open-label, multicenter study was performed in AD patients in Germany. First, detection of S. aureus was performed in all patients using the swab or scrub-wash method of sampling, followed by quantitative culture or quantitative polymerase chain reaction. Repeatability and reproducibility of all method combinations were evaluated to select the best combination of sampling and quantification. Second, a lotion containing HT La1 was applied to lesional skin twice daily for 3 weeks. Scoring using local objective SCORing Atopic Dermatitis (SCORAD), measurement of S. aureus load, and lesional microbiome analysis were performed before and after the 3-week treatment period.

Results

Thirty-one patients with AD were included in the study. All sampling and quantification methods were found to be robust, reproducible, and repeatable for assessing S. aureus load. For simplicity, a combination of swab and quantitative polymerase chain reaction was chosen to assess the efficacy of HT La1. Following application of a lotion containing HT La1 to AD lesions for 3 weeks, a reduction in S. aureus load was observed in patients, which correlated with a decrease in local objective SCORAD. Interestingly, high baseline skin concentrations of S. aureus were associated with good responses to the lotion.

Conclusion

This study demonstrated that the application of a lotion containing HT La1 to the lesional skin of patients with AD for 3 weeks controlled S. aureus colonization and was associated with local clinical improvement (SCORAD). These findings support further development of topical treatments containing heat-treated nonreplicating beneficial bacteria for patients with AD.

Decolonization of Staphylococcus aureus carriage

Staphylococcus aureus nasal colonization is a well-known independent risk factor for infection caused by this bacterium. Screening and decolonization of carriers have been proven effective in reducing S. aureus infections in some populations. However, a gap remains between what has been proven effective and what is currently done. We aimed to summarize recommendations and current knowledge of S. aureus decolonization to answer the following questions: Why? For whom? How? When? And what are the perspectives?

Identifying Hemodialysis Patients With the Highest Risk of Staphylococcus aureus Endogenous Infection Through a Simple Nasal Sampling Algorithm

In contrast to Staphylococcus aureus intermittent nasal carriers, persistent ones have the highest risk of infection. This study reports the usefulness of a simple nasal sampling algorithm to identify the S. aureus nasal carriage state of hemodialysis patients (HPs) and their subsequent risk of infection.From a cohort of 85 HPs, 76 were screened for S. aureus nasal carriage once a week during a 10-week period. The S. aureus nasal load was quantified by using either culture on chromogenic medium or fully automated real-time polymerase chain reaction assay. Molecular typing was used to compare strains from carriage and infection.The algorithm based on quantitative cultures was able to determine the status of S. aureus nasal carriage with a sensitivity of 95.8%, a specificity of 94.2%, a positive predictive value of 88.5%, and a negative predictive value of 98.0%. Of note, the determination of the S. aureus carriage state was obtained on the first nasal sample for all the 76 HPs, but 1 (98.7%). The algorithm based on quantitative polymerase chain reaction assay directly from the specimen yielded similar performances. During the 1-year follow-up after the last sampling episode, HPs classified as persistent nasal carriers with the algorithm were found to have a higher risk of S. aureus infection than those classified as nonpersistent carriers (P < 0.05), especially for infections of endogenous origin (P < 0.001).This simple algorithm is reliable for determining the S. aureus nasal carriage status in clinical practice and could contribute to characterize at an early stage of take-up patients with the highest risk of S. aureus infection.

Molecular dynamics of Staphylococcus aureus nasal carriage in Hajj pilgrims

During the 2012 Hajj season, the risk of acquisition of Staphylococcus aureus nasal carriage in a cohort of French pilgrims was 22.8%, and was statistically associated with the acquisition of viral respiratory pathogens (p 0.03). The carriage of S. aureus belonging to the emerging clonal complex 398 significantly increased following the pilgrimage (p < 0.05).

Epidemiology and microbiological investigations of community-acquired pneumonia in children admitted at the emergency department of a university hospital

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Systematic antimicrobials are recommended in community-acquired pneumonia of child.

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A large panel of bacteria and viruses was detected in 85 children exhibiting CAP.

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More than 60% of children with CAP exhibited an exclusive viral infection.

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A co-infection with at least 2 viruses was observed in >40% of the children.

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Data suggest that the use of antimicrobials in child's CAP should be revisited.

Background

The management of children with community-acquired pneumonia (CAP) is largely influenced by the development of new molecular diagnostic tests that allow the simultaneous detection of a wide range of pathogens.

Objectives

Evaluation of a diagnostic approach including multiplex PCR assays for revisiting the epidemiology and etiology of CAP in children at hospital.

Study design

Children of all ages consulting at the Emergency Department of the University hospital of Saint-Etienne, France, during the 2012–2013 winter period were included. In addition to bacterial cultures, the following pathogens were detected using biplex commercially-available rt-PCR tests: adenovirus, respiratory syncytial virus, human metapneumovirus, bocavirus, rhinovirus/enterovirus, coronavirus, influenza viruses A and B, parainfluenza viruses, Mycoplasma pneumoniae and Chlamydophila pneumonia.

Results

From 85 patients with CAP, at least one pathogen was identified in 81 cases (95.3%), including 4 bacterial exclusive infections (4.7%), 53 viral exclusive infections (62.4%) and 24 mixed infections (28.2%). Coinfection by at least two viruses was observed in 37 cases (43.5%). Mean age was higher in the case of documented bacterial infection (P < 0.05). In the subgroup of viral exclusive infection, the mean age of severe cases was 2.0 years vs 3.8 years in mild and moderate cases (P < 0.05).

Conclusions

These findings highlight the huge proportion of CAP of viral origin, the high number of co-infection by multiple viruses and the low number of bacterial CAP, notably in children under 5 years, and address the need to re-evaluate the indications of empiric antimicrobial treatment in this age group.

Detection and clinical relevance of Staphylococcus aureus nasal carriage: an update

Staphylococcus aureus nasal carriage is a well-defined risk factor of infection with this bacterium. The increased risk of S. aureus infection in nasal carriers is supported by the fact that the strains isolated from both colonization and infection sites are indistinguishable in most of the cases. Persistent nasal carriage seems to be associated with an increased risk of infection and this status could be defined now in clinical routine by using one or two quantitative nasal samples. There is evidence for supporting the detection of nasal carriage of S. aureus in patients undergoing cardiac surgery and in those undergoing hemodialysis in order to implement decolonization measures. More studies are needed to determine which carriers have the highest risk of infection and why decolonization strategies failed to reduce S. aureus infection in some other groups of patients.