ABSTRACT
Lung cancer is a leading cause of morbidity and mortality globally, with its high mortality rate attributed mainly to non-small cell lung cancer (NSCLC). Although immunotherapy with immune checkpoint inhibitors (ICI) has revolutionized its treatment, patient response is highly variable and lacking predictive markers. We conducted a prospective study on 55 patients with NSCLC undergoing ICI therapy to identify predictive markers of both response and immune-related adverse events (IrAEs) in the airway microbiota. We also analyzed the clinical evolution and overall survival (OS) with respect to treatments that affect the integrity of the microbiota, such as antibiotics and corticosteroids. Our results demonstrated that respiratory microbiota differ significantly in ICI responders: they have higher alpha diversity values and lower abundance of the Firmicutes phylum and the Streptococcus genus. Employing a logistic regression model, the abundance of Gemella was the major predictor of non-ICI response, whereas Lachnoanaerobaculum was the best predictor of a positive response to ICI. The most relevant results were that antibiotic consumption is linked to a lower ICI response, and the use of corticosteroids correlated with poorer overall survival. Whereas previous studies have focused on gut microbiota, our findings highlight the importance of the respiratory microbiota in predicting the treatment response. Future research should explore microbiota modulation strategies to enhance immunotherapy outcomes. Understanding the impact of antibiotics, corticosteroids, and microbiota on NSCLC immunotherapy will help personalize treatment and improve patient outcomes.
ABSTRACT
Background: Recurrent acute cholangitis (RAC) is a relatively uncommon entity that presents significant management difficulties. We present the case of a patient with RAC in whom the number of episodes was reduced after a novel therapeutic procedure. Case report: A 93-year-old male who in June 2019 was admitted for chills without fever, shivering, epigastric abdominal pain and moderate jaundice. Both abdominal ultrasound and CT scan showed intrahepatic and extrahepatic duct dilatation up to the papilla with no evidence of mass at that level. Endoscopic retrograde cholangiopancreatography (ERCP) was performed and abundant biliary sludge was removed. E. coli was identified as the cause of several of the episodes. Some isolates were shown to produce extended spectrum beta-lactamase (ESBL). Papillotomy was performed and plastic prosthesis and later a metallic prosthesis were implanted. Several months later a surgical bypass of the biliary tract was performed due to persistent episodes of cholangitis. When the chronic suppressive antibiotic treatment subsequently instituted to prevent new episodes of cholangitis failed, it was decided to perform a fecal microbiota transplant from a healthy donor and to suspend the chronic suppressive treatment. Since then, she has not presented new episodes of RAC for more than 10 months of clinical follow-up. BLEE-producing E. coli in the gastrointestinal tract could not be eradicated. Comment: Chronic colonization of the biliary tract by certain enterobacteria such as E. coli has been identified as a relevant pathogenic factor in cases of RAC. FMT may be a promising tool to improve the clinical course of patients with RAC.
ABSTRACT
Identifying the nutritional requirements and growth conditions of microorganisms is crucial for determining their applicability in industry and understanding their role in clinical ecology. Predatory bacteria such as Bdellovibrio bacteriovorus have emerged as promising tools for combating infections by human bacterial pathogens due to their natural killing features. Bdellovibrio's lifecycle occurs inside prey cells, using the cytoplasm as a source of nutrients and energy. However, this lifecycle supposes a challenge when determining the specific uptake of metabolites from the prey to complete the growth inside cells, a process that has not been completely elucidated. Here, following a model-based approach, we illuminate the ability of B. bacteriovorus to replicate DNA, increase biomass, and generate adenosine triphosphate (ATP) in an amino acid-based rich media in the absence of prey, keeping intact its predatory capacity. In this culture, we determined the main carbon sources used and their preference, being glutamate, serine, aspartate, isoleucine, and threonine. This study offers new insights into the role of predatory bacteria in natural environments and establishes the basis for developing new Bdellovibrio applications using appropriate metabolic and physiological methodologies. KEY POINTS: ⢠Amino acids support axenic lifestyle of Bdellovibrio bacteriovorus. ⢠B. bacteriovorus preserves its predatory ability when growing in the absence of prey.
Subject(s)
Adenosine Triphosphate , Amino Acids , Bdellovibrio bacteriovorus , Carbon , Amino Acids/metabolism , Carbon/metabolism , Bdellovibrio bacteriovorus/metabolism , Bdellovibrio bacteriovorus/physiology , Adenosine Triphosphate/metabolism , Culture Media/chemistry , BiomassABSTRACT
The function of many bacterial processes depends on the formation of functional membrane microdomains (FMMs), which resemble the lipid rafts of eukaryotic cells. However, the mechanism and the biological function of these membrane microdomains remain unclear. Here, we show that FMMs in the pathogen methicillin-resistant Staphylococcus aureus (MRSA) are dedicated to confining and stabilizing proteins unfolded due to cellular stress. The FMM scaffold protein flotillin forms a clamp-shaped oligomer that holds unfolded proteins, stabilizing them and favoring their correct folding. This process does not impose a direct energy cost on the cell and is crucial to survival of ATP-depleted bacteria, and thus to pathogenesis. Consequently, FMM disassembling causes the accumulation of unfolded proteins, which compromise MRSA viability during infection and cause penicillin re-sensitization due to PBP2a unfolding. Thus, our results indicate that FMMs mediate ATP-independent stabilization of unfolded proteins, which is essential for bacterial viability during infection.
Subject(s)
Bacterial Proteins , Membrane Microdomains , Membrane Proteins , Methicillin-Resistant Staphylococcus aureus , Membrane Proteins/metabolism , Membrane Microdomains/metabolism , Methicillin-Resistant Staphylococcus aureus/metabolism , Bacterial Proteins/metabolism , Protein Unfolding , Adenosine Triphosphate/metabolism , Penicillin-Binding Proteins/metabolism , Penicillin-Binding Proteins/genetics , Penicillin-Binding Proteins/chemistry , Humans , Protein Stability , Staphylococcal Infections/microbiology , Staphylococcal Infections/metabolism , Animals , MiceABSTRACT
This cross-sectional study investigates the methicillin-resistant Staphylococcus aureus (MRSA): its prevalence, antimicrobial resistance, and molecular characteristics in healthy swine populations in central Portugal. A total of 213 samples were collected from pigs on twelve farms, and MRSA prevalence was assessed using selective agar plates and confirmed via molecular methods. Antimicrobial susceptibility testing and whole genome sequencing (WGS) were performed to characterize resistance profiles and genetic determinants. Among the 107 MRSA-positive samples (83.1% prevalence), fattening pigs and breeding sows exhibited notably high carriage rates. The genome of 20 isolates revealed the predominance of the ST398 clonal complex, with diverse spa types identified. Antimicrobial susceptibility testing demonstrated resistance to multiple antimicrobial agents, including penicillin, cefoxitin, and tetracycline. WGS analysis identified a diverse array of resistance genes, highlighting the genetic basis of antimicrobial resistance. Moreover, virulence gene profiling revealed the presence of genes associated with pathogenicity. These findings underscore the significant prevalence of MRSA in swine populations and emphasize the need for enhanced surveillance and control measures to mitigate zoonotic transmission risks. Implementation of prudent antimicrobial use practices and targeted intervention strategies is essential to reducing MRSA prevalence and safeguarding public health. Continued research efforts are warranted to elucidate transmission dynamics and virulence potential, ultimately ensuring food safety and public health protection.
Subject(s)
Anti-Bacterial Agents , Methicillin-Resistant Staphylococcus aureus , Staphylococcal Infections , Swine Diseases , Animals , Methicillin-Resistant Staphylococcus aureus/genetics , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/pathogenicity , Swine , Staphylococcal Infections/veterinary , Staphylococcal Infections/microbiology , Staphylococcal Infections/epidemiology , Staphylococcal Infections/drug therapy , Cross-Sectional Studies , Swine Diseases/microbiology , Swine Diseases/epidemiology , Anti-Bacterial Agents/pharmacology , Microbial Sensitivity Tests , Portugal/epidemiology , Whole Genome Sequencing , Virulence Factors/genetics , Prevalence , Drug Resistance, Multiple, Bacterial/geneticsABSTRACT
Immune checkpoint inhibitors have been proposed as the standard treatment for different stages of non-small-cell lung cancer in multiple indications. Not all patients benefit from these treatments, however, and certain patients develop immune-related adverse events. Although the search for predictors of response to these drugs is a major field of research, these issues have yet to be resolved. It has been postulated that microbiota could play a relevant role in conditioning the response to cancer treatments; however, the human factor of intestinal permeability also needs to be considered as it is closely related to the regulation of host-microbiota interaction. In this article, we analyzed the possible relationship between the response to immune checkpoint inhibitors and the onset of immune-related adverse events, gut microbiota status, and intestinal membrane permeability. In a pioneering step, we also measured short-chain fatty acid content in feces. Although the correlation analyses failed to identify predictive biomarkers, even when all variables were integrated, our patients' microbial gut ecosystems were rich and diverse, and the intestinal barrier's integrity was preserved. These results add new knowledge on the composition of microbiota and its correlation with barrier permeability and short-chain fatty acids and suggest that more studies are required before these potential biomarkers can be incorporated into the clinical management of patients via immune checkpoint inhibitor treatment.
ABSTRACT
The acquisition and expression of antibiotic resistance implies changes in bacterial cell physiology, imposing fitness costs. Many human opportunistic pathogenic bacteria, such as those causing urinary tract or bloodstream infections, colonize the gut. In this opinionated review, we will examine the various types of stress that these bacteria might suffer during their intestinal stay. These stresses, and their compensatory responses, probably have a fitness cost, which might be additive to the cost of expressing antibiotic resistance. Such an effect could result in a disadvantage relative to antibiotic susceptible populations that might replace the resistant ones. The opinion proposed in this paper is that the effect of these combinations of fitness costs should be tested in antibiotic resistant bacteria with susceptible ones as controls. This testing might provide opportunities to increase the bacterial gut stress boosting physiological biomolecules or using dietary interventions. This approach to reduce the burden of antibiotic-resistant populations certainly must be answered empirically. In the end, the battle against antibiotic resistance should be won by antibiotic-susceptible organisms. Let us help them prevail.
Subject(s)
Anti-Bacterial Agents , Sepsis , Humans , Anti-Bacterial Agents/pharmacology , Anxiety , Drug Resistance, Microbial , ExerciseABSTRACT
Serratia spp. is a well-recognized pathogen in neonates; however, limited data are available in adults. We studied microbiological and clinical characteristics of Serratia spp. causing bloodstream infections (BSI) in our institution (January 2005-July 2020). Overall, 141 BSI episodes affecting 139 patients were identified and medical records reviewed. Antimicrobial susceptibility was recovered from our informatics system and 118 isolates from 116 patients were available for further microbiological studies. Whole genome sequencing (WGS) was completed in 107 isolates. Incidence of Serratia BSI was 0.3/1000 overall admissions (range 0.12-0.60), with maximum prevalence (27 episodes, 19.1%) during 2017-2018. Relevant patients' clinical characteristics were 71.9% ≥60 years (n = 100), with high comorbidity rates (49%, ≥2), 23 (74.2%) of them died within 1 month of the BSI episode. WGS identified all isolates as Serratia marcescens when Kraken bioinformatics taxonomic tool was used despite some which were identified as Serratia nematodiphila (32/118) or Serratia ureilytica (5/118) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Nevertheless, when using MASH distance, Serratia nevei (63/107), S. ureilytica (38/107), and S. marcescens (6/107) were assigned. Carbapenemase (blaVIM-1) and extended-spectrum ß-lactases (ESBL) (blaSHV-12) genes were found in seven and three isolates, respectively, one of them expressing both genes. The worldwide-disseminated IncL/M scaffold plasmid was identified in six VIM producers. Four genotypes were established based on their virulence factors and resistome. Serratia spp. emerged as a relevant nosocomial pathogen causing BSI in elderly patients in our hospital, particularly in recent years with a remarkable increase in antibiotic resistance. ESBL and carbapenemases production related to plasmid dissemination are particularly noteworthy.IMPORTANCESerratia spp. is the third most frequent pathogen involved in outbreaks at neonatal facilities and is primarily associated with bacteremia episodes. In this study, we characterized all causing bloodstream infection (BSI) in patients admitted to our hospital during a 16-year period (2005-2020). Despite having no neonatal intensive care unit in our hospital, this study revealed that Serratia spp. is a relevant pathogen causing BSI in elderly patients with high comorbidity rates. A significant increase of antimicrobial resistance was detected over time, particularly in 2020 and coinciding with the coronavirus disease (COVID-19) pandemic and nosocomial spread of multidrug-resistant Serratia spp. isolates. extended-spectrum ß-lactases and carbapenemases genes associated with plasmid dissemination, typically detected in other Enterobacterales species, were also identified, reinforcing the role of Serratia spp. in the antimicrobial resistance landscape. Additionally, this work highlights the need to reclassify the species of Serratia, since discrepancies were observed in the identification when using different tools.
Subject(s)
Cross Infection , Sepsis , Infant, Newborn , Adult , Humans , Aged , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial , Serratia , beta-Lactamases/genetics , Sepsis/microbiology , Serratia marcescens , Cross Infection/microbiology , Microbial Sensitivity Tests , LactaseABSTRACT
INTRODUCTION: All organs of any organism can be affected by helminths. They can be seen in a broad spectrum, from simple infestations to extensive, life-threatening involvement. Symptomatology is usually of chronic latent course. However, sometimes the presentation is acute and requires urgent surgical intervention. MATERIAL AND METHODS: We conducted a retrospective observational prospective recruitment study of patients undergoing emergency surgery for helminth infection from January 2000 to December 2019 at a university hospital. Sociodemographic and analytical variables, variables related to the clinical process, and the diagnostic test were analysed. Variables related to the surgical procedure and postoperative complications were also analysed. RESULTS: A total of 36 patients required emergency surgery for their helminth infection, which represented 0.26% of emergency abdominal surgeries. The mean age was 34.91 ± 21.5 years, with a predominance of men (69.4%). Most patients presented with pain in the right iliac fossa (69.4%), followed by symptoms compatible with intestinal obstruction (19.4%). The most frequent surgical interventions were appendectomy (38.9%) followed bowel resection (33.3%) and ileocecal resection (11.1%). Enterobious vermicularis and Anisakis simplex both together accounted for 75% of the sample. Statistically significant differences were identified in age (p < 0.001), diagnostic test performed (p = 0.032), intraoperative clinical diagnosis (p = 0.005) and surgical treatment received (p < 0.001). CONCLUSION: The frequency of emergency surgeries for intestinal helminth parasitism is decreasing. However, the majority of these are E. vermicularis and Anisakis simplex, which have distinctly different clinical presentations. Identification and recognition by physicians continue to be necessary for further postoperative management and possible complications.
Subject(s)
Helminthiasis , Hospitals, University , Intestinal Diseases, Parasitic , Humans , Male , Female , Adult , Retrospective Studies , Helminthiasis/epidemiology , Helminthiasis/parasitology , Helminthiasis/surgery , Middle Aged , Intestinal Diseases, Parasitic/epidemiology , Intestinal Diseases, Parasitic/parasitology , Intestinal Diseases, Parasitic/surgery , Young Adult , Adolescent , Aged , Child , Prospective StudiesABSTRACT
The genomes of four clinical Gram-negative ESKAPE bacterial strains highly resistant to the last-resort antibiotic colistin were sequenced and analyzed. The strains were found to carry multidrug-resistant genes besides colistin-resistant genes.
ABSTRACT
The indiscriminate use of antibiotics has contributed to the dissemination of multiresistant bacteria, which represents a public health concern. The aim of this work was to characterize 27 coagulase-negative staphylococci (CoNS) isolated from eight wild Northeast Atlantic hakes (Merluccius merluccius, L.) and taxonomically identified as Staphylococcus epidermidis (n = 16), Staphylococcus saprophyticus (n = 4), Staphylococcus hominis (n = 3), Staphylococcus pasteuri (n = 2), Staphylococcus edaphicus (n = 1), and Staphylococcus capitis (n = 1). Biofilm formation was evaluated with a microtiter assay, antibiotic susceptibility testing was performed using the disk diffusion method, and antibiotic resistance and virulence determinants were detected by PCR. Our results showed that all staphylococci produced biofilms and that 92.6% of the isolates were resistant to at least one antibiotic, mainly penicillin (88.8%), fusidic acid (40.7%), and erythromycin (37%). The penicillin resistance gene (blaZ) was detected in 66.6% (18) of the isolates, of which 10 also carried resistance genes to macrolides and lincosamides (mphC, msr(A/B), lnuA, or vgaA), 4 to fusidic acid (fusB), and 3 to trimethoprim-sulfamethoxazole (dfrA). At least one virulence gene (scn, hla, SCCmecIII, and/or SCCmecV) was detected in 48% of the isolates. This study suggests that wild European hake destined for human consumption could act as a vector of CoNS carrying antibiotic resistance genes and/or virulence factors.
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Acute myocardial infarction (AMI) is associated with systemic inflammatory processes and metabolic alterations. Microbial-derived metabolites, such as short-chain fatty acids and trimethylamine N-oxide (TMAO), have emerged in recent years as key players in the modulation of inflammation, with potential implications for cardiovascular diseases. We performed a prospective observational study that monitored the serological concentration of bacterial metabolites in 45 young patients (<55 years) without cardiovascular risk factors but with AMI, at hospital admission and at 3 months of follow-up, and compared them with a control group. TMAO and acetate levels were significantly higher in AMI, whereas butyrate and propionate were significantly lower. The acetate/propionate ratio showed the most discrimination between AMI and controls by receiver operating characteristic analysis (area under the curve 0.769, P < 0.0001). A multivariate logistic regression model revealed that this ratio was independently associated with AMI. Short-chain fatty acid concentrations, but not TMAO, exhibited significant correlations with inflammatory and coagulation parameters. Three months after the acute AMI event, all metabolite levels returned to those observed in healthy controls except butyrate. In conclusion, our study reveals disturbances of the serological concentration of microbiota-derived metabolites in AMI that are also related to inflammatory and coagulation parameters. These findings highlight an interesting field of study in the potential role of microbial metabolites from gut in cardiovascular disease.
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Human papillomavirus can cause preinvasive, high-grade squamous intraepithelial lesions (HSILs) as precursors to cancer in the anogenital area, and the microbiome is suggested to be a contributing factor. Men who have sex with men (MSM) living with human immunodeficiency virus (HIV) have a high risk of anal cancer, but current screening strategies for HSIL detection lack specificity. Here, we investigated the anal microbiome to improve HSIL screening. We enrolled participants living with HIV, divided into a discovery (n = 167) and validation cohort (n = 46), and who were predominantly (93.9%) cisgender MSM undergoing HSIL screening with high-resolution anoscopy and anal biopsies. We identified no microbiome composition signatures associated with HSILs, but elevated levels of microbiome-encoded proteins producing succinyl coenzyme A and cobalamin were significantly associated with HSILs in both cohorts. Measurement of these candidate biomarkers alone in anal cytobrushes outperformed anal cytology as a diagnostic indicator for HSILs, increasing the sensitivity from 91.2% to 96.6%, the specificity from 34.1% to 81.8%, and reclassifying 82% of false-positive results as true negatives. We propose that these two microbiome-derived biomarkers may improve the current strategy of anal cancer screening.
Subject(s)
Anus Neoplasms , HIV Infections , Sexual and Gender Minorities , Male , Humans , Homosexuality, Male , HIV Infections/complications , Vitamin B 12 , Early Detection of Cancer/methods , Anus Neoplasms/diagnosis , Anus Neoplasms/pathology , Biomarkers , PapillomaviridaeABSTRACT
Garlic (Allium sativum) has historically been associated with antioxidant, immunomodulatory, and microbiocidal properties, mainly due to its richness in thiosulfates and sulfur-containing phytoconstituents. Sepsis patients could benefit from these properties because it involves both inflammatory and refractory processes. We evaluated the effects of thiosulfinate-enriched Allium sativum extract (TASE) on the immune response to bacterial lipopolysaccharide (LPS) by monocytes from healthy volunteers (HVs) and patients with sepsis. We also explored the TASE effects in HIF-1α, described as the key transcription factor leading to endotoxin tolerance in sepsis monocytes through IRAK-M expression. Our results showed TASE reduced the LPS-triggered reactive oxygen species (ROS) production in monocytes from both patients with sepsis and HVs. Moreover, this extract significantly reduced tumor necrosis factor (TNF)-α, interleukin-1ß, and interleukin-6 production in LPS-stimulated monocytes from HVs. However, TASE enhanced the inflammatory response in monocytes from patients with sepsis along with increased expression of human leukocyte antigen-DR. Curiously, these dual effects of TASE on immune response were also found when the HV cohort was divided into low- and high-LPS responders. Although TASE enhanced TNFα production in the LPS-low responders, it decreased the inflammatory response in the LPS-high responders. Furthermore, TASE decreased the HIF-1α pathway-associated genes IRAK-M, VEGFA and PD-L1 in sepsis cells, suggesting HIF-1α inhibition by TASE leads to higher cytokine production in these cells as a consequence of IRAK-M downregulation. The suppression of this pathway by TASE was confirmed in vitro with the prolyl hydroxylase inhibitor dimethyloxalylglycine. Our data revealed TASE's dual effect on monocyte response according to status/phenotype and suggested the HIF-1α suppression as the possible underlying mechanism.
Subject(s)
Garlic , Sepsis , Humans , Antioxidants/pharmacology , Garlic/metabolism , Lipopolysaccharides/pharmacology , Lipopolysaccharides/metabolism , Monocytes/metabolism , Sepsis/metabolism , Tumor Necrosis Factor-alpha/metabolismABSTRACT
The Enterobacter cloacae complex (ECC) encompasses heterogeneous clusters of species that have been associated with nosocomial outbreaks. These species may have different acquired antimicrobial resistance and virulence mechanisms, and their identification is challenging. This study aims to develop predictive models based on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) profiles and machine learning for species-level identification. A total of 219 ECC and 118 Klebsiella aerogenes clinical isolates from three hospitals were included. The capability of the proposed method to differentiate the most common ECC species (Enterobacter asburiae, Enterobacter kobei, Enterobacter hormaechei, Enterobacter roggenkampii, Enterobacter ludwigii, and Enterobacter bugandensis) and K. aerogenes was demonstrated by applying unsupervised hierarchical clustering with principal-component analysis (PCA) preprocessing. We observed a distinctive clustering of E. hormaechei and K. aerogenes and a clear trend for the rest of the ECC species to be differentiated over the development data set. Thus, we developed supervised, nonlinear predictive models (support vector machine with radial basis function and random forest). The external validation of these models with protein spectra from two participating hospitals yielded 100% correct species-level assignment for E. asburiae, E. kobei, and E. roggenkampii and between 91.2% and 98.0% for the remaining ECC species; with data analyzed in the three participating centers, the accuracy was close to 100%. Similar results were obtained with the Mass Spectrometric Identification (MSI) database developed recently (https://msi.happy-dev.fr) except in the case of E. hormaechei, which was more accurately identified with the random forest algorithm. In short, MALDI-TOF MS combined with machine learning was demonstrated to be a rapid and accurate method for the differentiation of ECC species.
Subject(s)
Algorithms , Enterobacter cloacae , Humans , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methodsABSTRACT
Colistin resistance is acquired by different lipopolysaccharide (LPS) modifications. We proposed to evaluate the of effect in vivo colistin resistance acquisition on the innate immune response. We used a pair of ST11 clone Klebsiella pneumoniae strains: an OXA-48, CTX-M-15 K. pneumoniae strain susceptible to colistin (CS-Kp) isolated from a urinary infection and its colistin-resistant variant (CR-Kp) from the same patient after prolonged treatment with colistin. No mutation of previously described genes for colistin resistance (pmrA, pmrB, mgrB, phoP/Q, arnA, arnC, arnT, ugdH, and crrAB) was found in the CR-Kp genome; however, LPS modifications were characterized by negative-ion matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The strains were cocultured with human monocytes to determine their survival after phagocytosis and induction to apoptosis. Also, monocytes were stimulated with bacterial LPS to study cytokine and immune checkpoint production. The addition of 4-amino-4-deoxy-l-arabinose (Ara4N) to lipid A of CR-Kp accounted for the colistin resistance. CR-Kp survived significantly longer inside human monocytes after being phagocytosed than did the CS-Kp strain. In addition, LPS from CR-Kp induced both higher apoptosis in monocytes and higher levels of cytokine and immune checkpoint production than LPS from CS-Kp. Our data reveal a variable impact of colistin resistance on the innate immune system, depending on the responsible mechanism. Adding Ara4N to LPS in K. pneumoniae increases bacterial survival after phagocytosis and elicits a higher inflammatory response than its colistin-susceptible counterpart.
Subject(s)
Colistin , Klebsiella Infections , Humans , Colistin/pharmacology , Lipopolysaccharides/pharmacology , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Immunity, Innate , Klebsiella pneumoniae , Cytokines , Klebsiella Infections/microbiology , Drug Resistance, Bacterial/genetics , Microbial Sensitivity TestsABSTRACT
Introduction. Klebsiella aerogenes is a nosocomial pathogen associated with drug resistance and healthcare-associated infections.Gap Statement. K. aerogenes is associated with hospital-acquired infections with the ability to acquire mechanisms of resistance to reserve antimicrobials; its clinical behaviour has been poorly documented.Objective. We proposed to investigate an outbreak of carbapenem-resistant K. aerogenes in a hospital that persisted for 4 months.Methods. The primary aim was to evaluate the molecular characteristics and the clonal relationships among the isolates. We characterized isolates by polymerase chain reaction (PCR) and pulsed-field gel electrophoresis (PFGE). The information was integrated with clinical and epidemiological data.Results. Fourteen strains were disseminated in an intensive care unit and different wards at the hospital. The overall mortality was 42.8â%, and mortality attributed to infection was 21.4â%; strains showed high rates of resistance to most of the antimicrobials tested and carried bla KPC-2, bla SHV-2 and bla CTXM-15 genes. PFGE analysis indicated 2 PFGE groups; 12/14 isolates were associated with subgroup A and were likely to be primarily responsible for the ï¬rst isolation and subsequent dissemination. The outbreak characteristics data showed prolonged hospitalization and previous use of antibiotics as potential risk factors.Conclusion. We consider that it is essential to perform phenotypic and genotypic identification of early genetic resistance mechanisms in K. aerogenes isolates, not only from infection sites but also from colonization, to prevent the spread of these multidrug-resistant (MDR) isolates.
Subject(s)
Anti-Infective Agents , Cross Infection , Enterobacter aerogenes , Klebsiella Infections , Humans , beta-Lactamases/genetics , Bacterial Proteins/genetics , Klebsiella Infections/epidemiology , Klebsiella pneumoniae/genetics , Argentina/epidemiology , Microbial Sensitivity Tests , Anti-Bacterial Agents/pharmacology , Hospitals , Cross Infection/epidemiologyABSTRACT
BACKGROUND: Folliculitis decalvans (FD) is a rare primary neutrophilic scarring alopecia whose etiology has not been completely elucidated yet. OBJECTIVE: The aim of the study was to determine if the follicular microbiota residing in FD-affected hair follicles had a distinct microbiological signature and if an aberrant immune response was present in the pathogenesis of FD. METHODS: We conducted a cross-sectional study of 10 patients affected by FD. Trichoscopy-guided follicular biopsies were taken from affected and healthy scalp to identify the follicular microbiome using next-generation sequencing. We searched for microbiological biomarkers of FD-affected follicles using the linear discriminant analysis (LDA) effect size (LEfSe) tool. Additionally, peripheral blood mononuclear cells were obtained, and their cytokine production was quantified after incubation with pathogen-associated molecular patterns isolated from patients' biopsies and compared with healthy controls. RESULTS: ß-diversity analysis showed statistically significant differences regarding bacteria comparing follicular microbiota of healthy and FD-affected hairs. Ruminococcaceae, Agathobacter sp., Tyzzerella sp., and Bacteriodales vadin HA21 family were good predictors of disease status. IL-10, TNF-α, and IL-6 levels were significantly decreased in patients after incubation with various strains of bacteria compared with controls. CONCLUSION: FD hair follicles have a specific heterogenous follicular bacterial microbiota signature. Additionally, these patients seem to have an impaired immunological response.