ABSTRACT
BACKGROUND: Transfusion-transmitted bacterial infections (TTBIs) are the main residual infectious complications of transfusions. Escherichia coli and platelet (PLT) concentrates may be epidemiologically associated, leading to severe, if not lethal, TTBIs. We investigated the genotypic and phenotypic reasons for this clinically deleterious combination. STUDY DESIGN AND METHODS: We investigated a French national E. coli strain collection related to six independent episodes of TTBIs. Their phenotypic characterizations included antibiotic susceptibility testing, growth testing under different culture conditions, serum survival assays, and virulence in a sepsis mouse model. Their genotypic characterizations included polymerase chain reaction phylotyping, whole genome sequencing, and a subsequent in silico analysis. RESULTS: We highlighted a selection process of highly extraintestinal virulent strains, mainly belonging to the B2 phylogroup, adapted to the hostile environment (high citrate concentration and a bactericidal serum effect) of apheresis-collected platelet concentrates (PCs). Compared to controls, the E. coli TTBI strains grew faster in the PCs due to a superior ability to capture iron. The in vitro growth performances were highly compatible with blood-derived product real-life conditions, including storage conditions and delays. The consistent serum resistance of TTBI strains promotes their survival in both the donor's and the receiver's blood and in the PCs. CONCLUSION: This study pointed out that E. coli strains responsible for TTBI exhibit very specific traits. They belong to the extraintestinal pathogenic phylogroups and have a high intrinsic virulence. They can be resistant to complement, capture iron, and grow in the apheresis-collected PCs. These findings therefore support the reinforcement of the postdonation information.
Subject(s)
Escherichia coli Infections/prevention & control , Escherichia coli/growth & development , Genotype , Phenotype , Transfusion Reaction/prevention & control , Animals , Bacterial Infections , Blood Platelets/microbiology , Escherichia coli/pathogenicity , France , Humans , Iron/metabolism , Mice , Plateletpheresis , Transfusion Reaction/microbiology , VirulenceABSTRACT
The figure in the original published version of this article was omitted.
ABSTRACT
Through the past decade, MALDI-TOF MS has been recognized as a fast and robust tool for identification of most bacteria in clinical microbiology. However, the accuracy of this method to identify Neisseria species is still debated, and few data are available about commensal Neisseria species identification. In this study, we assessed two MALDI-TOF MS systems (Bruker Biotyper and Andromas) for the identification of 88, 18, and 29 isolates of Neisseria gonorrhoeae, Neisseria meningitidis, and commensal Neisseria species, respectively. All 88 isolates of N. gonorrhoeae were correctly identified using both systems, and most N. meningitidis and commensal Neisseria species were well identified: only 1/18 isolates of N. meningitidis was misidentified using Bruker Biotyper, and 1 isolate of Neisseria polysaccharea was misidentified as N. meningitidis using both systems. These results strengthen the possibility to use MALDI-TOF MS as a single method for Neisseria identification in routine, with excellent performance for N. gonorrhoeae identification. However, results should be interpreted prudently for N. meningitdis and commensal Neisseria species when isolated from genital and oropharyngeal samples where these both species can coexist.
Subject(s)
Neisseria/classification , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/instrumentation , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Biological Specimen Banks , Humans , Neisseria/isolation & purification , Neisseria gonorrhoeae/isolation & purification , Neisseria meningitidis/isolation & purification , SymbiosisABSTRACT
Stenotrophomonas maltophilia (Sm) is an archetypal environmental opportunistic bacterium responsible for health care-associated infections. The role of animals in human Sm infections is unknown. This study aims to reveal the genetic and phylogenetic relationships between pathogenic strains of Sm, both animal and human, and identify a putative role for animals as a reservoir in human infection. We phenotypically and genotypically characterized 61 Sm strains responsible for animal infections (mainly respiratory tract infections in horses) from a French nationwide veterinary laboratory network. We tested antimicrobial susceptibility and performed MLST and genogrouping using the concatenation of the seven housekeeping genes from the original MLST scheme. Excluding the eight untypeable strains owing to the lack of gene amplification, only 10 out of the 53 strains yielded a known ST (ST5, ST39, ST162, ST8, ST27, ST126, ST131). The genogroup distribution highlighted not only genogroups (genogroups 5 and 9) comprised exclusively of animal strains but also genogroups shared by human and animal strains. Interestingly, these shared genogroups were primarily groups 2 and 6, which have previously been identified as the two most frequent genogroups among human-pathogenic Sm strains, especially among respiratory pathogens. The antimicrobial susceptibility testing underlined the presence of acquired resistance: 18.8 and 7.5% of the tested isolates were resistant to the sulfonamide-trimethoprim combination and ciprofloxacin, respectively. Animal strains of Sm shared phylogenetic traits with some of the most successful human strains. The exact relationships between the human and animal strains, and the genetic support of these common traits, need to be determined.
Subject(s)
Disease Reservoirs/microbiology , Gram-Negative Bacterial Infections/veterinary , Horses/microbiology , Phylogeny , Respiratory Tract Diseases/veterinary , Stenotrophomonas maltophilia/genetics , Animals , Anti-Bacterial Agents/pharmacology , Cross Infection/microbiology , Gram-Negative Bacterial Infections/microbiology , Gram-Negative Bacterial Infections/transmission , Humans , Microbial Sensitivity Tests , Multilocus Sequence Typing , Phenotype , Respiratory Tract Diseases/microbiology , Stenotrophomonas maltophilia/classification , Stenotrophomonas maltophilia/drug effects , Stenotrophomonas maltophilia/isolation & purificationABSTRACT
An extended-spectrum ß-lactamase (ESBL)-producing and colistin-resistant Klebsiella pneumoniae clinical isolate was recovered from a patient who was treated with cefotaxime. This isolate harbored a blaCTX-M-15 ESBL gene that was associated with an ISEcp1 insertion sequence. Transposition of that tandem occurred within the chromosomal mgrB gene, leading to inactivation of the mgrB gene and consequently to acquired resistance to colistin. We showed here a coselection of colistin resistance as a result of a broad-spectrum cephalosporin selective pressure.
Subject(s)
Anti-Bacterial Agents/pharmacology , Cephalosporins/pharmacology , Colistin/pharmacology , Klebsiella pneumoniae/drug effects , Cefotaxime/pharmacology , Cephalosporin Resistance/genetics , Drug Resistance, Bacterial/genetics , Klebsiella pneumoniae/metabolism , Microbial Sensitivity TestsABSTRACT
Multiresistance in staphylococci constitutes a major challenge for the antimicrobial chemotherapy of invasive infections such as bacteraemia or bone and joint infections (BJIs). A nationwide prospective study was performed to detect antimicrobial resistance trends among staphylococci causing invasive infections. Between October 2011 and February 2012, 367 meticillin-resistant Staphylococcus aureus (MRSA) and 695 coagulase-negative staphylococci (CoNS) were collected from 37 French hospitals, mainly from bacteraemia (59.9%) and osteoarticular infections (29.0%). Minimum inhibitory concentrations (MICs) were determined by broth microdilution, and specific screening and confirmation tests were performed to detect heterogeneous vancomycin-intermediate S. aureus (hVISA). Staphylococcal isolates exhibiting a linezolid MIC>4 mg/L were further characterised to determinate their clonal relationships and the mechanism of resistance. MRSA exhibited additional resistances, including levofloxacin (82% associated resistance), gentamicin (13.6%), fusidic acid (13.6%) and rifampicin (6.5%), compromising oral step-down therapy in BJIs. Only two hVISA strains (0.5%) were identified. Among the CoNS, mainly Staphylococcus epidermidis (506/695; 72.8%), resistance to first- and second-line agents was more common. Linezolid resistance was identified in 10 CoNS (1.4%). The most frequent linezolid resistance mechanism was the G2576T mutation in 23S rDNA (9/10). For the first time in France, the cfr gene was found in five related sequence type 2 (ST2) S. epidermidis from two different hospitals, in association with ribosomal RNA and L3 ribosomal protein mutations. These national data must be considered when selecting empirical treatment for invasive staphylococcal infections. Moreover, the emergence and spread of linezolid-resistant CoNS carrying the cfr gene is of concern.
Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial/genetics , Linezolid/pharmacology , Methicillin-Resistant Staphylococcus aureus/drug effects , Staphylococcal Infections/drug therapy , Bacterial Proteins/genetics , Coagulase/genetics , France , Fusidic Acid/pharmacology , Gentamicins/pharmacology , Hospitals , Humans , Levofloxacin/pharmacology , Methicillin/pharmacology , Methicillin-Resistant Staphylococcus aureus/genetics , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Microbial Sensitivity Tests , Prospective Studies , RNA, Ribosomal, 23S/genetics , Rifampin/pharmacology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Staphylococcal Infections/microbiology , Staphylococcus epidermidis/isolation & purificationABSTRACT
OBJECTIVES: Mupirocin is the cornerstone of decolonization regimens, a successful strategy to prevent healthcare-associated staphylococcal infections. Several recent studies have reported alarming results: (i) an extending reservoir of mupA, the ancestral mobile resistance gene, among coagulase-negative staphylococci (CoNS); (ii) the emergence of a new resistance gene (mupB); and (iii) a growing number of mupirocin-resistant methicillin-resistant Staphylococcus aureus (MRSA), including highly pathogenic clones. We performed a nationwide prospective study in France to detect such trends among invasive staphylococci. METHODS: Between October 2011 and February 2012, 367 MRSA and 708 CoNS invasive isolates were collected from 37 hospitals and analysed centrally. Mupirocin MICs were determined using the broth microdilution method. mupA/B PCR was performed for resistant isolates (MIC >1 mg/L). Genetic relatedness between mupirocin-resistant MRSA isolates was determined by PFGE analysis and related isolates were tested by microarray. RESULTS: Among MRSA isolates 2.2% (nâ=â8) were classified as mupirocin resistant; 1.4% (nâ=â5) showing low-level resistance (MIC ≤256 mg/L) and 0.8% (nâ=â3) high-level resistance (MIC >256 mg/L). Only the latter isolates carried mupA. A clonal relationship was identified between two mupA-negative MRSA from the same hospital and three mupA-positive MRSA from three distant towns; these three isolates belonged to the Lyon clone. Mupirocin resistance was identified in 10.3% of CoNS, mainly highly resistant mupA-positive isolates (5.6%). The mupB gene was not detected in mupirocin-resistant MRSA or CoNS. CONCLUSIONS: This first large national study indicates the need for thorough epidemiological monitoring and a stewardship programme to prevent and detect mupirocin resistance in staphylococci.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Drug Resistance, Bacterial , Mupirocin/pharmacology , Nuclear Proteins/genetics , Staphylococcal Infections/microbiology , Staphylococcus/drug effects , DNA, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field , France/epidemiology , Microarray Analysis , Microbial Sensitivity Tests , Molecular Epidemiology , Molecular Typing , Polymerase Chain Reaction , Prospective Studies , Staphylococcal Infections/epidemiologyABSTRACT
BACKGROUND: Pathogenesis of coagulase-negative staphylococcal bloodstream infections among preterm neonates is debated: central venous catheters (CVCs) are considered the major cause and the cornerstone of prevention measures. The role of other means of transmission is unknown. METHODS: We developed a specific quantitative polymerase chain reaction assay targeting the dnaJ gene from Staphylococcus epidermidis and Staphylococcus capitis to detect DNA from CVC used in preterms. Performance of the polymerase chain reaction was tested against 2 control groups of CVC yielding positive (n = 24) or negative (n = 63) conventional cultures. We also explored retrospectively the DNA load of CVC having a negative conventional bacterial culture and obtained from 34 very preterm neonates with catheter-related bloodstream infections (CR-BSIs) established by usual clinical and biologic criteria. RESULTS: The molecular approach allowed detection of corresponding DNA from all the positive control catheters. Among the 34 episodes of CR-BSI yielding a negative conventional CVC culture, 8 (23.5%) had a positive polymerase chain reaction signal (5 S. epidermidis and 3 S. capitis). This percentage did not significantly differ according to the staphylococcal species, the delay between the CVC insertion and the beginning of the sepsis or between the blood culture collection and the CVC removal. These results conform to the previously published 70% of CR-BSI for whom the origin could be questioned. CONCLUSIONS: CVC removal in preterms is often performed in cases of CR-BSI; our study supports the hypothesis that in some cases the responsibility of CVC is questionable.
Subject(s)
Bacteremia/epidemiology , Catheter-Related Infections/epidemiology , Central Venous Catheters/microbiology , Infant, Extremely Premature , Staphylococcal Infections/epidemiology , Staphylococcus/isolation & purification , Bacteremia/microbiology , Catheter-Related Infections/microbiology , HSP40 Heat-Shock Proteins/genetics , Humans , Infant, Newborn , Prevalence , Real-Time Polymerase Chain Reaction/methods , Staphylococcal Infections/microbiology , Staphylococcus/classification , Staphylococcus/geneticsABSTRACT
Genes, active during normal development, are frequently reactivated during neoplastic transformation and may be related to progression. One of them, the transcription factor TP63, is crucial for pulmonary epithelial development and a possible target of the recurrent 3q amplifications in lung squamous cell carcinoma (SCC). Here, we explored whether TP63 reactivation could be associated to cancer progression in lung SCC through an epithelial to mesenchymal transition. We studied TP63 amplification and TP63 expression at RNA and protein levels and we analyzed the ΔNTP63/TATP63 ratio that quantifies the proportion of the isoform lacking the transactivation domain/the isoform containing the transactivation domain. We correlated TP63 status to survival and to the expression of epithelial (E-cadherin and plakoglobin) and mesenchymal (N-cadherin, vimentin, TWIST1, and SNAIL) markers. We found that high ΔN/TA TP63 ratio was related to high E-cadherin and plakoglobin mRNA levels (P < 0.05) and that E-cadherin mRNA level was the only marker related to survival. Kaplan-Meier survival curves stratified according to the expression level of E-cadherin showed, as already reported in breast cancer, that patients with low (first quartile) or high (last quartile) E-cadherin expression had a worse survival with respect to patients with intermediate E-cadherin expression. Altogether, our results indicate that a reactivation of ΔNTP63 is linked to the maintenance of epithelial markers and suggest that E-cadherin has a dual role in lung SCC.
Subject(s)
Carcinoma, Squamous Cell/pathology , Gene Expression Regulation, Neoplastic , Lung Neoplasms/pathology , Transcription Factors/genetics , Tumor Suppressor Proteins/genetics , Aged , Cadherins/biosynthesis , Carcinoma, Squamous Cell/genetics , Carcinoma, Squamous Cell/mortality , Desmoplakins/biosynthesis , Female , Gene Amplification , Humans , Lung Neoplasms/genetics , Lung Neoplasms/mortality , Male , Middle Aged , gamma CateninABSTRACT
BACKGROUND: Infliximab is effective for the treatment of refractory inflammatory bowel disease (IBD). Nevertheless, up to 40% of patients lose response to infliximab over time. The aim was to assess the clinical value of measuring infliximab trough levels and antibodies to infliximab (ATI) concentrations in IBD patients who lost response to infliximab therapy. METHODS: We retrospectively studied records of IBD patients who lost response to infliximab therapy. We first assessed clinical responses of different therapeutic strategies that were applied when patients lost response to infliximab and then we looked at the correlation between clinical response and infliximab trough levels and ATI concentrations. RESULTS: Seventy-six IBD patients were included. 31/76 patients (41%) continued infliximab therapy without any modification, 39 patients (51%) had an intensification of infliximab therapy, five patients (7%) had switched to adalimumab therapy, and one patient (1%) underwent surgery. Clinical response was observed in 27 patients (69%) with an intensification of infliximab therapy. There was no significant difference in mean infliximab trough level at inclusion in patients who responded to intensification of infliximab therapy (3.3 ± 4.1 µg/mL) as compared with patients who did not respond (2.3 ± 2.2 µg/mL, P = 0.85). In all, 16/76 patients (22.4%) presented detectable ATI in the serum. Ten ATI-positive patients had an intensification of infliximab therapy and six (60%) demonstrated a clinical response. After intensification of infliximab therapy the ATI concentration decreased in five patients. CONCLUSIONS: In patients with IBD who lose response to infliximab, clinical improvement may occur upon intensification of infliximab therapy, irrespective of infliximab serum concentration or presence of ATI.
Subject(s)
Anti-Inflammatory Agents/therapeutic use , Antibodies, Monoclonal, Humanized/therapeutic use , Antibodies/blood , Inflammatory Bowel Diseases/drug therapy , Inflammatory Bowel Diseases/immunology , Adalimumab , Adult , Anti-Inflammatory Agents/blood , Anti-Inflammatory Agents/immunology , Antibodies, Monoclonal, Humanized/blood , Antibodies, Monoclonal, Humanized/immunology , Female , Humans , Inflammatory Bowel Diseases/blood , Male , Prognosis , Retrospective Studies , Tumor Necrosis Factor-alpha/antagonists & inhibitorsABSTRACT
The use of TNF-α antagonists has substantially improved the care of many patients with inflammatory and autoimmune diseases. However, approximately one third of such patients fail to respond well to treatment, regardless of the antagonist used or of the underlying disease. The mechanisms underlying these failures are analyzed in this review, and proposals made concerning how best to adapt therapeutic decisions in these instances.