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Class-B1 G-protein-coupled receptors (GPCRs) are an important family of clinically relevant drug targets that remain difficult to investigate via high-throughput screening and in animal models. Here, we engineered PAClight1P78A, a novel genetically encoded sensor based on a class-B1 GPCR (the human PAC1 receptor, hmPAC1R) endowed with high dynamic range (ΔF/F0 = 1100%), excellent ligand selectivity, and rapid activation kinetics (τON = 1.15 s). To showcase the utility of this tool for in vitro applications, we thoroughly characterized and compared its expression, brightness and performance between PAClight1P78A-transfected and stably expressing cells. Demonstrating its use in animal models, we show robust expression and fluorescence responses upon exogenous ligand application ex vivo and in vivo in mice, as well as in living zebrafish larvae. Thus, the new GPCR-based sensor can be used for a wide range of applications across the life sciences empowering both basic research and drug development efforts.
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Peixe-Zebra , Animais , Peixe-Zebra/metabolismo , Peixe-Zebra/genética , Camundongos , Humanos , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/genética , Células HEK293 , Técnicas Biossensoriais/métodos , Engenharia de Proteínas/métodos , LigantesRESUMO
We describe the inter-regional spread of a novel ESBL-producing Escherichia coli subclone (ST131H89) in long-term care facility residents, general population, and environmental water sources in Western Switzerland between 2017 and 2020. The study highlights the importance of molecular surveillance for tracking emerging antibiotic-resistant pathogens in healthcare and community settings.
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Infecções por Escherichia coli , Proteínas de Escherichia coli , Humanos , Infecções por Escherichia coli/epidemiologia , Suíça , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Antibacterianos , beta-Lactamases , Epidemiologia MolecularRESUMO
Introduction: Stress is one of the highest-ranked work-related injuries worldwide and has become almost universal among the Nigerian workforce. English as a Second Language (ESL) teachers face enormous work-related threats that lead to occupational stress. When ESL teachers are stressed, students' language development and entire educational progress are at risk. This is mostly underscored as English, though a second language, serves as the language of instruction in Nigerian schools. As a result, managing occupational stress is particularly important for ESL teachers, as it is among the definitive ways of improving ESL learning and overall educational outcomes. This study examined the effectiveness of online cognitive behavioral intervention (o-CBI) in lowering occupational stress among ESL teachers. Method: ESL teachers with at least 1 year of experience were among the participants (N = 89). Participants were divided into two groups: the intervention group (N = 44) and the control group (N = 45). For 9 weeks, the experimental group engaged in nine sessions of 2 h of the o-CBI program. The Single Item Stress Questionnaire (SISQ), the Satisfaction with Therapy and Therapist Scale-Revised (STTS-R), and the Teachers' Stress Inventory (TSI) were the measures used to collect primary and secondary data. Four sets of data were collected at baseline, post-test, and follow-up 1 and 2 evaluations. The data were analyzed using mean, standard deviation, t-test statistics, repeated measures ANOVA, and bar charts. Results and discussion: Compared to the control group, the o-CBT group had significantly lower TSI scores at the post-test (Time 2) and follow-up evaluations (Times 3 and 4). Between pre-, post-, and follow-up 1 and 2 measurements, there were no significant differences in occupational stress index scores in the control group. It was concluded that o-CBI is effective in job-stress treatment among ESL teachers. In addition, implications for school health policy are discussed. The o-CBI for occupational stress was well received by the participants, showing high acceptability among ESL teachers.
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Background: Increasing reports of multidrug resistance (MDR) in clinical Pseudomonas aeruginosa have led to a necessity for new antimicrobials. Ceftazidime-avibactam (CZA) is indicated for use against MDR P. aeruginosa across a broad range of infection types and particularly those that are carbapenem resistant. This study sought to determine the molecular mechanisms of CZA and imipenem (IPM)-resistance in clinical P. aeruginosa isolates obtained from Swiss hospitals. Methods: Clinical P. aeruginosa isolates were obtained from inpatients in three hospitals in Switzerland. Susceptibility was determined by either antibiotic disc testing or broth microdilution according to EUCAST methodology. AmpC activity was determined using cloxacillin and efflux activity was determined using phenylalanine-arginine ß-naphthylamide, in agar plates. Whole Genome Sequencing was performed on 18 clinical isolates. Sequence types (STs) and resistance genes were ascertained using the Centre for Genomic Epidemiology platform. Genes of interest were extracted from sequenced isolates and compared to reference strain P. aeruginosa PAO1. Results: Sixteen different STs were identified amongst the 18 isolates in this study indicating a high degree of genomic diversity. No carbapenemases were detected but one isolate did harbor the ESBL bla PER-1. Eight isolates were CZA-resistant with MICs ranging from 16-64 mg/L, and the remaining ten isolates had either low/wildtype MICs (n=6; 1-2 mg/L) or elevated, but still susceptible, MICs (n=4; 4-8 mg/L). Ten isolates were IPM-resistant, seven of which had mutations resulting in truncations of OprD, and the remaining nine IPM-susceptible isolates had intact oprD genes. Within CZA-R isolates, and those with reduced susceptibility, mutations resulting in ampC derepression, OprD loss, mexAB overexpression and ESBL (bla PER-1) carriage were observed in various combinations and one harbored a truncation of the PBP4 dacB gene. Within the six isolates with wildtype-resistance levels, five had no mutations that would affect any antimicrobial resistance (AMR) genes of interest when compared to PAO1. Conclusion: This preliminary study highlights that CZA-resistance in P. aeruginosa is multifactorial and could be caused by the interplay between different resistance mechanisms including ESBL carriage, increased efflux, loss of permeability and derepression of its intrinsic ampC.
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Infecções por Pseudomonas , Pseudomonas aeruginosa , Humanos , Pseudomonas aeruginosa/genética , Antibacterianos/farmacologia , Suíça , Combinação de Medicamentos , beta-Lactamases/genética , Testes de Sensibilidade MicrobianaRESUMO
At our tertiary children's hospital, infections with newly detected methicillin-resistant Staphylococcus aureus (MRSA) among children attending primary (age 6-12 years) and secondary school (age 13-16 years) nearly doubled in 2018 compared to previous years. This observation initiated an epidemiological outbreak investigation including phenotypic (susceptibility testing) and genotypic (whole genome sequencing) characterization of the isolates. In addition, a cross-sectional study was conducted to determine source of the outbreak, colonization frequency and to identify risk factors for transmission using a questionnaire. As a result, 49 individuals were detected with 57 corresponding isolates. Based on the case definition combined with whole genome sequencing, a core cluster was identified that shared common genetic features and a similar antimicrobial susceptibility pattern (efflux-mediated macrolide resistance, tetracycline susceptibility along with presence of Panton-Valentine leukocidin). Epidemiologic evaluation identified a distinct school as a common risk factor. However, the source of the clustered infections within that school could not be further specified. No further cases could be detected after decolonization of infected and colonized children.
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Staphylococcus aureus Resistente à Meticilina , Humanos , Criança , Adolescente , Staphylococcus aureus Resistente à Meticilina/genética , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Estudos Transversais , Suíça/epidemiologia , Farmacorresistência Bacteriana , Macrolídeos , Surtos de Doenças , Instituições AcadêmicasRESUMO
BACKGROUND: Data on antimicrobial resistance mechanisms are scanty for Cedecea spp., with very variable antibiotic resistance patterns documented. Here we report the first in vivo resistance evolution of a C. davisae clinical isolate in a patient with a complex hand trauma and provide insight in the resistance mechanism, leading to therapeutic implications for this pathogen. CASE PRESENTATION: Cedecea davisae was isolated from a patient with hand trauma during a first surgical debridement. Six days after primary surgical treatment and under antimicrobial treatment with amoxicillin-clavulanic acid and later cefepime, follow up cultures yielded C. davisae which demonstrated a resistance development. The susceptible parental isolate and its resistant derivative were characterized by whole genome sequencing, ampC, ompC and ompF by RT- PCR. The resistant derivative demonstrated an A224G SNP in ampD, the transcriptional regulator of ampC, leading to a His75Arg change in the corresponding AmpD protein. AmpC transcription of the resistant derivative was 362-times higher than the susceptible isolate. Transcription levels of ompF and ompC were 8.5-fold and 1.3-fold lower, respectively, in the resistant derivative. Downregulation of OmpF putatively resulted from a mutation in the presumed promoter region upstream of the dusB-Fis operon, a proposed regulator for ompF. CONCLUSIONS: This case demonstrates the in vivo resistance development of C. davisae within 7 days similar to that of the members of the Enterobacter cloacae complex. Our findings add valuable information for future therapeutic management of these opportunistic pathogens as they warrant the same empirical treatment as AmpC producers.
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Proteínas de Bactérias , beta-Lactamases , Antibacterianos/uso terapêutico , Proteínas de Bactérias/genética , Enterobacteriaceae , Humanos , Testes de Sensibilidade Microbiana , beta-Lactamases/genéticaRESUMO
BACKGROUND: Despite the adoption of strict infection prevention and control measures, many hospitals have reported outbreaks of multidrug-resistant organisms (MDRO) during the Coronavirus 2019 (COVID-19) pandemic. Following an outbreak of carbapenem-resistant Acinetobacter baumannii (CRAB) in our institution, we sought to systematically analyse characteristics of MDRO outbreaks in times of COVID-19, focussing on contributing factors and specific challenges in controlling these outbreaks. METHODS: We describe results of our own CRAB outbreak investigation and performed a systematic literature review for MDRO (including Candida auris) outbreaks which occurred during the COVID-19 pandemic (between December 2019 and March 2021). Search terms were related to pathogens/resistance mechanisms AND COVID-19. We summarized outbreak characteristics in a narrative synthesis and contrasted contributing factors with implemented control measures. RESULTS: The CRAB outbreak occurred in our intensive care units between September and December 2020 and comprised 10 patients (thereof seven with COVID-19) within two distinct genetic clusters (both ST2 carrying OXA-23). Both clusters presumably originated from COVID-19 patients transferred from the Balkans. Including our outbreak, we identified 17 reports, mostly caused by Candida auris (n = 6) or CRAB (n = 5), with an overall patient mortality of 35% (68/193). All outbreaks involved intensive care settings. Non-adherence to personal protective equipment (PPE) or hand hygiene (n = 11), PPE shortage (n = 8) and high antibiotic use (n = 8) were most commonly reported as contributing factors, followed by environmental contamination (n = 7), prolonged critical illness (n = 7) and lack of trained HCW (n = 7). Implemented measures mainly focussed on PPE/hand hygiene audits (n = 9), environmental cleaning/disinfection (n = 9) and enhanced patient screening (n = 8). Comparing potentially modifiable risk factors and control measures, we found the largest discrepancies in the areas of PPE shortage (risk factor in 8 studies, addressed in 2 studies) and patient overcrowding (risk factor in 5 studies, addressed in 0 studies). CONCLUSIONS: Reported MDRO outbreaks during the COVID-19 pandemic were most often caused by CRAB (including our outbreak) and C. auris. Inadequate PPE/hand hygiene adherence, PPE shortage, and high antibiotic use were the most commonly reported potentially modifiable factors contributing to the outbreaks. These findings should be considered for the prevention of MDRO outbreaks during future COVID-19 waves.
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Infecções por Acinetobacter/prevenção & controle , Acinetobacter baumannii , COVID-19/complicações , COVID-19/epidemiologia , Candida auris , Candidíase/prevenção & controle , Pandemias , SARS-CoV-2 , Infecções por Acinetobacter/complicações , Acinetobacter baumannii/efeitos dos fármacos , Idoso , Candidíase/complicações , Carbapenêmicos/farmacologia , Infecção Hospitalar/prevenção & controle , Surtos de Doenças/prevenção & controle , Farmacorresistência Bacteriana Múltipla , Feminino , Humanos , Controle de Infecções/métodos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Suíça/epidemiologiaRESUMO
OBJECTIVES: We aimed to assess the burden of extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales in Swiss long-term care facilities (LTCFs) to describe the molecular epidemiology, describe the intrainstitutional and regional clusters of resistant pathogens, and identify independent institution- and resident-level factors associated with colonization. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: From August to October 2019, we performed a point prevalence study among residents from 16 LTCFs in Western and Eastern Switzerland (8 per region). METHODS: Residents underwent screening for ESBL-producing Enterobacterales (ESBL-E); whole-genome sequencing (WGS) was performed. We gathered institution-level (eg, number of beds, staff-resident ratio, alcoholic hand rub consumption) and resident-level [eg, anthropometric data, time in facility, dependency, health care exposure, antibiotic treatment, proton-pump inhibitor (PPI) use] characteristics. Factors associated with colonization were identified using a generalized linear model. RESULTS: Among 1185 eligible residents, 606 (51%) consented to the study. ESBL-E prevalence was 11.6% (70/606), ranging from 1.9% to 33.3% between institutions, with a median of 12.5% in the West and 6.9% in the East (P = .03). Among 59 Escherichia coli (from 58 residents), multilocus sequence type (ST) 131 was most common (n = 43/59, 73%), predominantly its subclone H30R1 (n = 37/43, 86%). WGS data identified multiple intrainstitutional and regional clusters. Independent risk factors for ESBL carriage were previous ESBL colonization [adjusted odds ratio (aOR) 23.5, 95% confidence interval (CI) 6.6-83.8, P < .001), male gender (aOR 2.6, 95% CI 1.5-4.6, P = .002), and use of PPIs (aOR 2.2, 95% CI 1.2-3.8, P = .01). CONCLUSIONS AND IMPLICATIONS: Overall ESBL-E prevalence in Swiss LTCF residents is low. Yet, we identified several clusters of residents with identical pathogens within the same institution. This implies that particularly affected institutions might benefit from targeted infection control interventions. PPI use was the only modifiable factor associated with carriage of ESBL producers. This study adds to the growing list of adverse outcomes associated with PPIs, calling for action to restrict their use in the long-term care setting.
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Infecções por Enterobacteriaceae/epidemiologia , Assistência de Longa Duração , Epidemiologia Molecular , Estudos Transversais , Enterobacteriaceae , Humanos , Prevalência , Fatores de Risco , beta-LactamasesRESUMO
BACKGROUND: Kidney pathologies often result in change in renal size. Knowledge of normal kidney sizes is important for screening, diagnosis, prognosis and follow-up management of paediatric renal diseases. OBJECTIVES: The aim of this study was to establish the age-, height- and weight-matched kidney dimensions in apparently healthy Nigerian children. METHOD: A descriptive, cross-sectional study of right and left kidney parameters (length, width, thickness and volume) of 1315 school-aged Nigerian children was conducted over 8 months. Ages ranged from 5 to 17 years. Parameters were obtained using a General Electric (GE) LOGIC 400CL ultrasound machine. Kidney dimensions were correlated with age, sex and anthropometric measurements. RESULTS: Normative values for all the kidney parameters for each age, height and weight groups and also gender were established for the study population. The left kidneys were noted to be longer and thicker, and of more volume than the right kidneys. The right kidneys were seen to be wider (p < 0.01). Length of the left kidneys in females was noted to be more than those of the males in the age- and weight-matched categories (p < 0.05). The width of both kidneys was higher in the males in all the categories (p < 0.05). Males showed higher values of thickness and volume in the height category. All the renal parameters significantly correlated with body size indicators, except for body mass index. CONCLUSION: This study has established gender-, age-, weight- and height-specific range of values of the kidney parameters of apparently healthy children together with regression models.
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Low back pain (LBP) is a common presenting complaint in our hospital in Enugu Nigeria. Three hundred thirty-three radiographs of patients with LBP were studied. A lot of them had bony outgrowths (osteophytes) on the spine. Plain radiograph of the spine is useful in studying these patients' condition. INTRODUCTION: Low back pain (LBP) is one of the common symptoms which bring patients to hospital and ultimately to radiology department for medical assistance. Plain radiographs of lumbar spine are usually the initial imaging tools requested by clinicians. The objective of this study is to evaluate commonest finding in patients with LBP to guide physicians for improved management. METHODS: This work was a retrospective study. Plain films of these patients with LBP at the University of Nigeria Teaching Hospital, Enugu, were assessed by two radiologists. Findings documented and analyzed using IBM'S SPSS 22. Association was determined using chi-square with level of significance, p < 0.05. RESULTS: Total number of radiographs reviewed was 333. One hundred and eighty-three (55.0%) patients were females. Age ranged from 14 to 101 years. Mean age of 53.4 ± 15.9 years. Disc space was normal in majority (55.3%, 184/333) of patients; narrowing was observed in most others (43.2%, 144/333), about half of the narrowing occurring along with vacuum phenomenon. Osteophytes were commonest finding in a total of 284/333 (85.3%) existing alone or in combination with other findings. Proportion of patients with osteophytes was highest in sixth to eighth decade of life (98.8% of 61-80 age group), followed by 41-60 age group (92.9%). This association between age group and the presence of osteophytes was statistically significant (p < 0.000). Anterior vertebral body was affected in 85.0% (284/333) of patients. CONCLUSIONS: Osteophytes are common radiologic features in LBP. Anterior vertebral body is most affected. It is commoner in the older age group. Plain radiograph is an invaluable imaging tool in the management of LBP in this part of the world.
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Dor Lombar/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Radiografia , Adulto , Idoso , Feminino , Humanos , Dor Lombar/etiologia , Masculino , Pessoa de Meia-Idade , Nigéria , Osteófito/complicações , Osteófito/diagnóstico por imagem , Estudos RetrospectivosRESUMO
The blaCMY -2/4-carrying IncB/O/K-like plasmids of seven Escherichia coli strains from poultry, poultry meat and human urine samples were examined using comparative analysis of whole plasmid sequences. The incompatibility group was determined by analysis of the incRNAI region and conjugation assays with strains containing the IncK and IncB/O reference plasmids. Strains were additionally characterized using MLST and MIC determination. The complete DNA sequences of all plasmids showed an average nucleotide identity of 91.3%. Plasmids were detected in E. coli sequence type (ST) 131, ST38, ST420, ST1431, ST1564 and belonged to a new plasmid variant (IncK2) within the IncK and IncB/O groups. Notably, one E. coli from poultry meat and one from human contained the same plasmid. The presence of a common recently recognized IncK2 plasmid in diverse E. coli from human urine isolates and poultry meat production suggests that the IncK2 plasmids originated from a common progenitor and have the capability to spread to genetically diverse E. coli in different reservoirs. This discovery is alarming and stresses the need of rapidly introducing strict hygiene measures throughout the food chain, limiting the spread of such plasmids in the human settings.
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INTRODUCTION: blaOXA-48, blaNDM-1 and blaCTX-M-3 are clinically relevant resistance genes, frequently associated with the broad-host range plasmids of the IncL/M group. The L and M plasmids belong to two compatible groups, which were incorrectly classified together by molecular methods. In order to understand their evolution, we fully sequenced four IncL/M plasmids, including the reference plasmids R471 and R69, the recently described blaOXA-48-carrying plasmid pKPN-El.Nr7 from a Klebsiella pneumoniae isolated in Bern (Switzerland), and the blaSHV-5 carrying plasmid p202c from a Salmonella enterica from Tirana (Albania). METHODS: Sequencing was performed using 454 Junior Genome Sequencer (Roche). Annotation was performed using Sequin and Artemis software. Plasmid sequences were compared with 13 fully sequenced plasmids belonging to the IncL/M group available in GenBank. RESULTS: Comparative analysis of plasmid genomes revealed two distinct genetic lineages, each containing one of the R471 (IncL) and R69 (IncM) reference plasmids. Conjugation experiments demonstrated that plasmids representative of the IncL and IncM groups were compatible with each other. The IncL group is constituted by the blaOXA-48-carrying plasmids and R471. The IncM group contains two sub-types of plasmids named IncM1 and IncM2 that are each incompatible. CONCLUSION: This work re-defines the structure of the IncL and IncM families and ascribes a definitive designation to the fully sequenced IncL/M plasmids available in GenBank.
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Anti-Infecciosos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Plasmídeos/genética , Sequência de Bases , Genoma Bacteriano/genética , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Mapeamento por Restrição , Análise de Sequência de DNARESUMO
The spread of antibiotic-resistant bacteria through food has become a major public health concern because some important human pathogens may be transferred via the food chain. Acinetobacter baumannii is one of the most life-threatening gram-negative pathogens; multidrug-resistant (MDR) clones of A. baumannii are spreading worldwide, causing outbreaks in hospitals. However, the role of raw meat as a reservoir of A. baumannii remains unexplored. In this study, we describe for the first time the antibiotic susceptibility and fingerprint (repetitive extragenic palindromic PCR [rep-PCR] profile and sequence types [STs]) of A. baumannii strains found in raw meat retailed in Switzerland. Our results indicate that A. baumannii was present in 62 (25.0%) of 248 (CI 95%: 19.7 to 30.9%) meat samples analyzed between November 2012 and May 2013, with those derived from poultry being the most contaminated (48.0% [CI 95%: 37.8 to 58.3%]). Thirty-nine strains were further tested for antibiotic susceptibility and clonality. Strains were frequently not susceptible (intermediate and/or resistant) to third- and fourth-generation cephalosporins for human use (i.e., ceftriaxone [65%], cefotaxime [32%], ceftazidime [5%], and cefepime [2.5%]). Resistance to piperacillin-tazobactam, ciprofloxacin, colistin, and tetracycline was sporadically observed (2.5, 2.5, 5, and 5%, respectively), whereas resistance to carbapenems was not found. The strains were genetically very diverse from each other and belonged to 29 different STs, forming 12 singletons and 6 clonal complexes (CCs), of which 3 were new (CC277, CC360, and CC347). RepPCR analysis further distinguished some strains of the same ST. Moreover, some A. baumannii strains from meat belonged to the clonal complexes CC32 and CC79, similar to the MDR isolates responsible for human infections. In conclusion, our findings suggest that raw meat represents a reservoir of MDR A. baumannii and may serve as a vector for the spread of these pathogens into both community and hospital settings.
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Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Carne/microbiologia , Filogenia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Animais , Bovinos , Contaminação de Alimentos/análise , Contaminação de Alimentos/estatística & dados numéricos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Aves Domésticas , Ovinos , Suínos , SuíçaRESUMO
We evaluated the pet food contained in 30 packages as a potential origin of extended-spectrum cephalosporin-resistant Gram-negative organisms and ß-lactamase genes (bla). Live bacteria were not detected by selective culture. However, PCR investigations on food DNA extracts indicated that samples harbored the blaCTX-M-15 (53.3%), blaCMY-4 (20%), and blaVEB-4-like (6.7%) genes. Particularly worrisome was the presence of blaOXA-48-like carbapenemases (13.3%). The original pet food ingredients and/or the production processes were highly contaminated with bacteria carrying clinically relevant acquired bla genes.
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Proteínas de Bactérias/genética , Plasmídeos/genética , beta-Lactamases/genética , Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/genética , Testes de Sensibilidade Microbiana , Reação em Cadeia da PolimeraseRESUMO
Extensively drug-resistant (XDR) Klebsiella pneumoniae isolates usually carry a single carbapenemase (e.g. KPC, NDM, OXA-48-like). Here we describe an XDR K. pneumoniae of sequence type 101 that was detected in the screening rectal swab of a patient transferred from the intensive care unit of a hospital located in Belgrade (Serbia) to Bern University Hospital (Switzerland). The isolate was resistant to all antibiotics with the exception of colistin [minimum inhibitory concentration] (MIC ≤ 0.125 µg/mL), tigecycline (MIC = 0.5 µg/mL) and fosfomycin (MIC = 2 µg/mL). The isolate co-possessed class B (NDM-1) and class D (OXA-48) carbapenemases, class A extended-spectrum ß-lactamase (CTX-M-15), class C cephalosporinase (CMY-16), ArmA 16S rRNA methyltransferase, substitutions in GyrA and ParC, loss of OmpK35 porin, as well as other genes conferring resistance to quinolones (qnrA), tetracyclines [tet(A)], sulfonamides (sul1, sul2), trimethoprim (dfrA12, dfrA14), rifampicin (arr-1), chloramphenicol (cmlA1, floR) and streptomycin (aadA1). The patient was placed under contact isolation precautions preventing the spread of this nearly untreatable pathogen.
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Proteínas de Bactérias/genética , Portador Sadio/microbiologia , Proteínas de Escherichia coli/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Metiltransferases/genética , beta-Lactamases/genética , Antibacterianos/farmacologia , Proteínas de Bactérias/biossíntese , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla , Proteínas de Escherichia coli/biossíntese , Fezes/microbiologia , Humanos , Unidades de Terapia Intensiva , Klebsiella pneumoniae/isolamento & purificação , Masculino , Metiltransferases/biossíntese , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Suíça , beta-Lactamases/biossínteseRESUMO
Here, we report a case of OXA-48-producing Salmonella enterica serovar Kentucky of sequence type 198 (ST198) from perianal screening cultures of a patient transferred from Libya to Switzerland. The blaOXA-48 gene was carried by Tn1999.2 and located on an â¼60-kb IncL/M plasmid. This Salmonella strain also possessed the blaVEB-8, aac(6)-Ib, tet(A), sul1, and mphA resistance genes and substitutions in GyrA (Ser83Phe and Asp87Asn) and ParC (Ser80Ile). This finding emphasizes that prompt screening strategies are essential to prevent the dissemination of carbapenemase producers imported from countries where they are endemic.
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Proteínas de Bactérias/metabolismo , Salmonella enterica/enzimologia , beta-Lactamases/metabolismo , Farmacorresistência Bacteriana Múltipla/genética , Humanos , Líbia , Salmonella enterica/genética , SuíçaRESUMO
UNLABELLED: The Mycobacterium tuberculosis genome includes the large family of pe_pgrs genes, whose functions are unknown. Because of precedents in other pathogens in which gene families showing high sequence variation are involved in antigenic variation, a similar role has been proposed for the pe_pgrs genes. However, the impact of immune selection on pe_pgrs genes has not been examined. Here, we sequenced 27 pe_pgrs genes in 94 clinical strains from five phylogenetic lineages of the M. tuberculosis complex (MTBC). We found that pe_pgrs genes were overall more diverse than the remainder of the MTBC genome, but individual members of the family varied widely in their nucleotide diversity and insertion/deletion (indel) content: some were more, and others were much less, diverse than the genome average. Individual pe_pgrs genes also differed in the ratio of nonsynonymous to synonymous mutations, suggesting that different selection pressures act on individual pe_pgrs genes. Using bioinformatic methods, we tested whether sequence diversity in pe_pgrs genes might be selected by human T cell recognition, the major mechanism of adaptive immunity to MTBC. We found that the large majority of predicted human T cell epitopes were confined to the conserved PE domain and experimentally confirmed the antigenicity of this domain in tuberculosis patients. In contrast, despite being genetically diverse, the PGRS domains harbored few predicted T cell epitopes. These results indicate that human T cell recognition is not a significant force driving sequence diversity in pe_pgrs genes, which is consistent with the previously reported conservation of human T cell epitopes in the MTBC. IMPORTANCE: Recognition of Mycobacterium tuberculosis antigens by T lymphocytes is known to be important for immune protection against tuberculosis, but it is unclear whether human T cell recognition drives antigenic variation in M. tuberculosis. We previously discovered that the known human T cell epitopes in the M. tuberculosis complex are highly conserved, but we hypothesized that undiscovered epitopes with naturally occurring sequence variants might exist. To test this hypothesis, we examined the pe_pgrs genes, a large family of genes that has been proposed to function in immune evasion by M. tuberculosis. We found that the pe_pgrs genes exhibit considerable sequence variation, but the regions containing T cell epitopes and the regions of variation are distinct. These findings confirm that the majority of human T cell epitopes of M. tuberculosis are highly conserved and indicate that selection forces other than T cell recognition drive sequence variation in the pe_pgrs genes.
Assuntos
Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Variação Genética , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/imunologia , Linfócitos T/imunologia , Biologia Computacional , DNA Bacteriano/química , DNA Bacteriano/genética , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Genótipo , Humanos , Mutação INDEL , Dados de Sequência Molecular , Mycobacterium tuberculosis/isolamento & purificação , Seleção Genética , Análise de Sequência de DNARESUMO
OBJECTIVES: Resistance to extended-spectrum cephalosporins (ESCs) in Escherichia coli can be due to the production of ESBLs, plasmid-mediated AmpCs (pAmpCs) or chromosomal AmpCs (cAmpCs). Information regarding type and prevalence of ß-lactamases, clonal relations and plasmids associated with the bla genes for ESC-R E. coli (ESC-R-Ec) detected in Switzerland is lacking. Moreover, data focusing on patients referred to the specialized outpatient clinics (SOCs) are needed. METHODS: We analysed 611 unique E. coli isolated during September-December 2011. ESC-R-Ec were studied with microarrays, PCR/DNA sequencing for blaESBLs, blapAmpCs, promoter region of blacAmpC, IS elements, plasmid incompatibility group, and also implementing transformation, aIEF, rep-PCR and MLST. RESULTS: The highest resistance rates were observed in the SOCs, whereas those in the hospital and community were lower (e.g. quinolone resistance of 22.6%, 17.2% and 9.0%, respectively; P = 0.003 for SOCs versus community). The prevalence of ESC-R-Ec in the three settings was 5.3% (n = 11), 7.8% (n = 22) and 5.7% (n = 7), respectively. Thirty isolates produced CTX-M ESBLs (14 were CTX-M-15), 5 produced CMY-2 pAmpC and 5 hyper-expressed cAmpCs due to promoter mutations. Fourteen isolates were of sequence type 131 (ST131; 10 with CTX-M-15). blaCTX-M and blaCMY-2 were associated with an intact or truncated ISEcp1 and were mainly carried by IncF, IncFII and IncI1plasmids. CONCLUSIONS: ST131 producing CTX-M-15 is the predominant clone. The prevalence of ESC-R-Ec (overall 6.5%) is low, but an unusual relatively high frequency of AmpC producers (25%) was noted. The presence of ESC-R-Ec in the SOCs and their potential ability to be exchanged between hospital and community should be taken into serious consideration.