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1.
J Antimicrob Chemother ; 76(5): 1332-1338, 2021 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-33585908

RESUMEN

BACKGROUND: The emergence of antibiotic-resistant species calls for fast and reliable phenotypic susceptibility testing to adapt clinical management as fast as possible. OBJECTIVES: We assessed the real-life performance of EUCAST rapid antimicrobial susceptibility testing (RAST) and analysed its impact on patient management. METHODS: RAST was performed on clinical blood cultures containing Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa or Acinetobacter baumannii complex. Categorical agreement with VITEK2 was analysed. A pre-post quasi-experimental observational study was designed to compare antibiotic treatment in sepsis patients in the RAST patient group (n = 51) and a historical control cohort (n = 54). RESULTS: In total, 436 isolates, corresponding to 2314 disc diameters, were measured; 18.4% of these measurements were in the area of technical uncertainty. For the 81.6% categorical results, which could be compared, 94.7% were in agreement, whereas 5.3% of the results were not. In the RAST group, optimal therapy was initiated on the same day as blood culture positivity, while this was the case in the historical group after 24 h. In six cases, RAST allowed for rapid antibiotic escalation. The 30 day mortality rate was lower in the RAST group, although this was not statistically significant. CONCLUSIONS: RAST provides a reliable tool to improve clinical management of sepsis patients by providing rapid phenotypic susceptibility data. While not necessarily being an instrument for de-escalation, especially in areas of low prevalence, early detection allows for timely coverage of resistant isolates. Thus, RAST significantly adds to successful antibiotic stewardship programmes.

2.
J Child Neurol ; : 883073821989154, 2021 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-33543660

RESUMEN

Intracerebroventricular enzyme replacement therapy (ICV-ERT) for CLN2 disease represents the first approved treatment for neuronal ceroid lipofuscinosis (NCL) diseases. It is the first treatment where a recombinant lysosomal enzyme, cerliponase alfa, is administered into the lateral cerebral ventricles to reach the central nervous system, the organ affected in CLN2 disease. If untreated, CLN2 children show first symptoms such as epilepsy and language developmental delay at 2-4 years followed by rapid loss of motor and language function, vision loss, and early death. Treatment with cerliponase alfa has shown to slow the rapid neurologic decline. However, the mode of administration by 4 hour-long intracerebroventricular infusions every 14 days represents a potentially greater risk of infection compared to intravenous enzyme replacement therapies. The Hamburg NCL Specialty Clinic was the first site worldwide to perform intracerebroventricular enzyme replacement therapy in children with CLN2 disease. In order to ensure maximum patient safety, we analysed data from our center from more than 3000 intracerebroventricular enzyme replacement therapies in 48 patients over 6 years with regard to the occurrence of device-related adverse events and device infections. Since starting intracerebroventricular enzyme replacement therapy, we have also developed and continuously improved the "Hamburg Best Practice Guidelines for ICV-Enzyme Replacement Therapy (ERT) in CLN2 Disease." Results from this study showed low rates for device-related adverse events and infections with 0.27% and 0.33%, respectively. Therefore, following our internal procedural guidelines has shown to improve standardization and patient safety of intracerebroventricular enzyme replacement therapy for CLN2 disease.

3.
PLoS Pathog ; 17(2): e1009304, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33544760

RESUMEN

S. epidermidis is a substantial component of the human skin microbiota, but also one of the major causes of nosocomial infection in the context of implanted medical devices. We here aimed to advance the understanding of S. epidermidis genotypes and phenotypes conducive to infection establishment. Furthermore, we investigate the adaptation of individual clonal lines to the infection lifestyle based on the detailed analysis of individual S. epidermidis populations of 23 patients suffering from prosthetic joint infection. Analysis of invasive and colonizing S. epidermidis provided evidence that invasive S. epidermidis are characterized by infection-supporting phenotypes (e.g. increased biofilm formation, growth in nutrient poor media and antibiotic resistance), as well as specific genetic traits. The discriminating gene loci were almost exclusively assigned to the mobilome. Here, in addition to IS256 and SCCmec, chromosomally integrated phages was identified for the first time. These phenotypic and genotypic features were more likely present in isolates belonging to sequence type (ST) 2. By comparing seven patient-matched nasal and invasive S. epidermidis isolates belonging to identical genetic lineages, infection-associated phenotypic and genotypic changes were documented. Besides increased biofilm production, the invasive isolates were characterized by better growth in nutrient-poor media and reduced hemolysis. By examining several colonies grown in parallel from each infection, evidence for genetic within-host population heterogeneity was obtained. Importantly, subpopulations carrying IS insertions in agrC, mutations in the acetate kinase (AckA) and deletions in the SCCmec element emerged in several infections. In summary, these results shed light on the multifactorial processes of infection adaptation and demonstrate how S. epidermidis is able to flexibly repurpose and edit factors important for colonization to facilitate survival in hostile infection environments.

4.
Int J Med Microbiol ; 311(2): 151477, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33524636

RESUMEN

OBJECTIVE: We aim to describe the epidemiological, clinical and microbiological characteristics of the linezolid- and vancomycin- resistant Enterococcus faecium (LVRE) in a tertiary care hospital in Germany. METHODS: We conducted a retrospective analysis of 196 LVRE cases observed from 1st January 2012 to 31th December 2018. Patients' medical charts were reviewed and available LVRE (n = 102) were subjected to whole-genome-sequencing. Antibiotic consumption was measured in defined daily dose (DDD)/100 bed-days (BD). RESULTS: The prevalence of LVRE isolates among VRE was 6.3 % in 2018. Most patients had an onco-hematological disease (134/196, 68.4 %). From 2012-2018 an increase of +356.7 % of linezolid defined daily dose/100 bed-days was observed. In 71.4 % (90/126, 70 missing values) of the patients, linezolid was prescribed in the previous 6 months. The median exposure to linezolid was 15 days (Interquartile, IQR 9-23). 42/196 (21.4 %) patients had an LVRE-related infection with an overall 30-day mortality rate of 33 %. In 121/196 (61.7 %) patients, linezolid-susceptible VREfm were isolated before LVRE, suggesting secondary acquisition of linezolid resistance. Genetic analysis revealed that most isolates belonged to ST117 (64/102 available isolates, 62.7 %). The G2576T 23S rDNA mutation was identified as the most common resistance mechanism (96/102, 94.1 %). poxtA was identified in two isolates, while cfr, and optrA were not detected. CONCLUSIONS: Incidence of LVRE related to 23S rDNA mutations is rising and probably associated with antibiotic consumption. Restrictions in the use of linezolid may be needed in order to retain therapeutic options in VRE.


Asunto(s)
Farmacorresistencia Bacteriana , Enterococcus faecium/efectos de los fármacos , Infecciones por Bacterias Grampositivas , Linezolid/farmacología , Resistencia a la Vancomicina , Antibacterianos/farmacología , Enterococcus faecium/genética , Alemania/epidemiología , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Infecciones por Bacterias Grampositivas/epidemiología , Humanos , Pruebas de Sensibilidad Microbiana , ARN Ribosómico 23S/genética , Estudios Retrospectivos , Vancomicina
6.
mBio ; 11(5)2020 10 20.
Artículo en Inglés | MEDLINE | ID: mdl-33082256

RESUMEN

Although it is normally an innocuous part of the human skin microbiota, Staphylococcus epidermidis has emerged as a major nosocomial pathogen, and implanted foreign materials are an essential risk factor for the development of an infection. The extraordinary efficiency of S. epidermidis to colonize artificial surfaces is particularly related to the ability to form biofilms. Biofilm formation itself critically depends on stable pathogen binding to extracellular host matrix components, e.g. fibronectin (Fn), covering inserted devices in vast amounts. Extracellular matrix binding protein (Embp) and its subdomains referred to as the F-repeat and the FG-repeat are critical for adherence of S. epidermidis to surface-immobilized Fn. Embp-Fn interactions preferentially occur with surface-bound, but not folded, globular Fn via binding to the F3 domain. High-resolution structure analysis of F- and FG-repeats revealed that both repeats are composed of two tightly connected triple α-helix bundles, exhibiting an elongated but rather rigid structural organization in solution. Both F- and FG-repeat possess Fn-binding capacity via interactions with type III subdomain FN12, involving residues within the C and F ß-sheet. FN12 essentially supports stability of the globular Fn state, and thus these findings reasonably explain why Embp-mediated interaction of S. epidermidis necessitates Fn surface immobilization. Thus, Embp employs an uncharacterized bacterial Fn-binding mechanism to promote staphylococcal adherence.IMPORTANCE Staphylococcus epidermidis is a leading pathogen in implant-associated hospital infections. The pathogenesis critically depends on bacterial binding to ECM components, specifically fibronectin (Fn). The cell surface-localized, 1-MDa extracellular matrix binding protein (Embp) is essentially characterized by 10 F- and 40 FG-repeats. These repetitive units, each characterized by two α-helical bundles, organize themselves in a rigid, elongated form. Embp binds preferentially to surface-localized but not soluble Fn, with both F- and FG-repeats being sufficient for Fn binding and resulting bacterial adherence. Binding preferentially involves Fn type III domain, specifically residues of FN12 ß-sheets C and F. Both play key role in stabilizing the globular Fn conformation, explaining the necessity of Fn surface immobilization for a subsequent interaction with Embp. In comparison to many other bacterial Fn-binding proteins using the Fn N terminus, Embp employs a previously undescribed mechanism supporting the adhesion of S. epidermidis to surface-immobilized Fn.

7.
BMC Infect Dis ; 20(1): 366, 2020 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-32448208

RESUMEN

BACKGROUND: Kosakonia cowanii, formerly known as Enterobacter cowanii, is a Gram-negative bacillus belonging to the order Enterobacterales. The species is usually recognized as a plant pathogen and has only anecdotally been encountered as a human pathogen. Here we describe the rare case of a K. cowanii infection presenting as an acute cholecystitis and provide a review of available literature. Evident difficulties in species identification by biochemical profiling suggests that potentially, K. cowanii might represent an underestimated human pathogen. CASE PRESENTATION: A 61-year old immunocompromised man presented to the hospital with fever and pain in the upper right abdomen. Sonography revealed an inflamed gall bladder and several gall stones. A cholecystectomy proved diagnosis of an acute cholecystitis with a partial necrosis of the gall bladder. Surgical specimen grew pure cultures of Gram-negative rods unambiguously identified as K. cowanii by MALDI-TOF, 16S-rRNA analysis and whole genome sequencing. CONCLUSIONS: Reporting cases of Kosakonia species can shed light on the prevalence and clinical importance of this rare cause of human infection. Our case is the first to describe an infection without prior traumatic inoculation of the pathogen from its usual habitat, a plant, to the patient. This raises the question of the route of infections as well as the pathogen's ability to colonize the human gut.


Asunto(s)
Colecistitis Aguda/diagnóstico , Colecistitis Aguda/microbiología , Infecciones por Enterobacteriaceae/diagnóstico , Enterobacteriaceae/genética , Enfermedades Raras/diagnóstico , Enfermedades Raras/microbiología , Colecistectomía , Infecciones por Enterobacteriaceae/microbiología , Vesícula Biliar/patología , Cálculos Biliares/cirugía , Humanos , Huésped Inmunocomprometido , Masculino , Persona de Mediana Edad , Necrosis , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Resultado del Tratamiento , Secuenciación Completa del Genoma
8.
Mycoses ; 63(5): 437-442, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32080902

RESUMEN

OBJECTIVES: Invasive fungal infections caused by Lomentospora prolificans are associated with very high mortality rates and can be challenging to treat given pan-drug resistance to available antifungal agents. The objective of this study was to describe the clinical presentation and outcomes in a cohort of patients with invasive L prolificans infections. METHODS: We performed a retrospective review of medical records of patients with invasive L prolificans infection in the FungiScope® registry of rare invasive fungal infections. Patients diagnosed between 01 January 2008 and 09 September 2019 were included in for analysis. RESULTS: The analysis included 41 patients with invasive L prolificans infection from eight different countries. Haematological/oncological malignancies were the most frequent underlying disease (66%), disseminated infection was frequent (61%), and the lung was the most commonly involved organ (44%). Most infections (59%) were breakthrough infections. Progression/deterioration/treatment failure was observed in 23/40 (58%) of patients receiving antifungal therapy. In total, 21/41 (51%) patients, and 77% of patients with underlying haematological/oncological malignancy, had a fatal outcome attributed to invasive fungal infection. Combination antifungal therapy was frequent (24/40) and associated with improved survival. In particular, treatment regimens including terbinafine were significantly associated with higher treatment success at final assessment (P = .012), with a positive trend observed for treatment regimens that included voriconazole (P = .054). CONCLUSIONS: Lomentospora prolificans infections were associated with mortality rates of 77% and above in patients with underlying haematological/oncological malignancies and those with disseminated infections. While combination therapy is the preferred option for now, the hope lies with novel antifungals currently under development.


Asunto(s)
Antifúngicos/uso terapéutico , Infecciones Fúngicas Invasoras/tratamiento farmacológico , Scedosporium/patogenicidad , Anciano , Femenino , Neoplasias Hematológicas/complicaciones , Neoplasias Hematológicas/microbiología , Humanos , Internacionalidad , Infecciones Fúngicas Invasoras/mortalidad , Masculino , Persona de Mediana Edad , Sistema de Registros , Estudios Retrospectivos , Resultado del Tratamiento
9.
BMC Infect Dis ; 20(1): 170, 2020 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-32087681

RESUMEN

BACKGROUND: Infectious meningitis is a serious disease and patient outcome relies on fast and reliable diagnostics. A syndromic panel testing approach like the FilmArray ME can accelerate diagnosis and therefore decrease the time to pathogen specific therapy. Yet, its clinical utility is controversial, mainly because of a remaining uncertainty in correct interpretation of results, limited data on its performance on clinical specimens and its relatively high costs. The aim of this study was to analyze clinical performance of the assay in a real life setting at a tertiary university hospital using a pragmatic and simple sample selection strategy to reduce the overall cost burden. METHODS: Over a period of 18 months we received 4623 CSF samples (2338 hospitalizations, 1601 individuals). FilmArray ME analysis was restricted to CSF-samples with a high pretest probability of infectious meningitis, e.g. positive Gram-stain, samples in which leukocytes and/or bacteria were evident or urgent suspicion of infection was communicated by clinicians. N = 171 samples matched to our risk criteria and were subjected to FilmArray ME analysis. Those samples were also analyzed by reference methods: culture only (n = 45), PCR only (n = 20) or both methods (n = 106). RESULTS: 56/171 (32.75%) were FilmArray ME positive. Bacterial pathogens were detected in 30/56 (53.57%), viral pathogens were detected in 27/56 (48.21%) and yeast DNA was detected in 1/56 (1.79%) of positive samples. Double detection occurred in 2/56 samples. In 52/56 (92.86%) FilmArray ME positive samples, results could be confirmed by the reference assays (sensitivity = 96.30%, specificity =96.58%). CONCLUSION: The FilmArray ME assay is a fast and reliable diagnostic tool for the management of infectious meningitis and can easily be implemented in routine diagnostic workflows. However, correlation of test results and underlying clinical symptoms requires experienced users and the awareness of potentially false negative or false positive results. Moreover, considering the need for antimicrobial susceptibility testing, the use of molecular tests as a stand-alone diagnostic cannot be recommended.


Asunto(s)
Pruebas Diagnósticas de Rutina/métodos , Encefalitis/diagnóstico , Meningitis/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena de la Polimerasa Multiplex/métodos , Coloración y Etiquetado/métodos , Pruebas Diagnósticas de Rutina/economía , Encefalitis/líquido cefalorraquídeo , Encefalitis/microbiología , Encefalitis/virología , Violeta de Genciana , Alemania , Hospitales Universitarios , Humanos , Laboratorios , Meningitis/líquido cefalorraquídeo , Meningitis/microbiología , Meningitis/virología , Técnicas de Diagnóstico Molecular/economía , Reacción en Cadena de la Polimerasa Multiplex/economía , Fenazinas , Estudios Prospectivos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Coloración y Etiquetado/economía , Centros de Atención Terciaria
10.
Crit Care ; 23(1): 399, 2019 12 09.
Artículo en Inglés | MEDLINE | ID: mdl-31815650

RESUMEN

BACKGROUND: Critically ill patients in the intensive care unit (ICU) are at high risk for developing Clostridioides difficile infections (CDI). Risk factors predicting their mortality or standardized treatment recommendations have not been defined for this cohort. Our goal is to determine outcome and mortality associated risk factors for patients at the ICU with CDI by evaluating clinical characteristics and therapy regimens. METHODS: A retrospective single-centre cohort study. One hundred forty-four patients (0.4%) with CDI-associated diarrhoea were included (total 36.477 patients admitted to 12 ICUs from January 2010 to September 2015). Eight patients without specific antibiotic therapy were excluded, so 132 patients were analysed regarding mortality, associated risk factors and therapy regimens using univariate and multivariate regression. RESULTS: Twenty-eight-day mortality was high in patients diagnosed with CDI (27.3%) compared to non-infected ICU patients (9%). Patients with non CDI-related sepsis (n = 40/132; 30.3%) showed further increase in 28-day mortality (45%; p = 0.003). Initially, most patients were treated with a single CDI-specific agent (n = 120/132; 90.9%), either metronidazole (orally, 35.6%; or IV, 37.1%) or vancomycin (18.2%), or with a combination of antibiotics (n = 12/132; 9.1%). Patients treated with metronidazole IV showed significantly longer duration of diarrhoea > 5 days (p = 0.006). In a multivariate regression model, metronidazole IV as initial therapy was an independent risk factor for delayed clinical cure. Immunosuppressants (p = 0.007) during ICU stay lead to increased 28-day mortality. CONCLUSION: Treatment of CDI with solely metronidazole IV leads to a prolonged disease course in critically ill patients.


Asunto(s)
Infecciones por Clostridium/tratamiento farmacológico , Diarrea/etiología , Factores de Tiempo , Anciano , Antiinfecciosos/administración & dosificación , Antiinfecciosos/uso terapéutico , /patogenicidad , Infecciones por Clostridium/epidemiología , Infecciones por Clostridium/mortalidad , Estudios de Cohortes , Enfermedad Crítica/terapia , Diarrea/clasificación , Femenino , Alemania/epidemiología , Humanos , Unidades de Cuidados Intensivos/organización & administración , Unidades de Cuidados Intensivos/estadística & datos numéricos , Masculino , Metronidazol/administración & dosificación , Metronidazol/uso terapéutico , Persona de Mediana Edad , Estudios Retrospectivos , Estadísticas no Paramétricas
11.
J Microbiol Methods ; 160: 104-106, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30953660

RESUMEN

Laser desorption-time of flight (LD-TOF) mass spectrometry-based detection of hemozoin was assessed for its performance characteristics as a rapid screening test for malaria. In spite of good specificity of >95%, poor sensitivity of 80.2% for microscopically positive samples makes the easy-to-apply and rapid approach unsuitable for the routine diagnostic setting.


Asunto(s)
Hemoproteínas/análisis , Malaria , Tamizaje Masivo/métodos , Plasmodium/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Humanos , Malaria/epidemiología , Malaria/microbiología , Sensibilidad y Especificidad
12.
Aging Male ; : 1-4, 2019 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-30879364

RESUMEN

Mucor is an angioinvasive fungus that was reported mainly in immunocompromised patients. It usually presents as rhino-orbital, pulmonary, gastrointestinal, and disseminated disease. Isolated renal mucormycosis is an extremely rare infection in immunocompetent patients and is associated with high fatality rate. Early diagnosis, prompt antifungal treatment, and surgery give the patient the best chance for cure and survival. We describe herein a case of renal zygomycosis caused by Apophysomyces elegans (A. elegans) in an immunocompetent host. To the best of our knowledge, this is the first case of renal A. elegans to be reported from Qatar and the Middle East.

13.
Ann Intensive Care ; 8(1): 10, 2018 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-29349705

RESUMEN

BACKGROUND: Stool cultures for Campylobacter, Salmonella and Shigella and/or Yersinia spp. are frequently ordered in critically ill patients with diarrhea. The aim of this study is to analyze the diagnostic yield in a large cohort of critically ill patients. Therefore, we performed a cohort study at the Department of Intensive Care Medicine of a University Hospital (11 ICUs). RESULTS: From all patients who were admitted to the ICU between 2010 and 2015, stool cultures were taken from 2.189/36.477 (6%) patients due to diarrhea. Results of all stool cultures tested for Campylobacter, Salmonella and Shigella and/or Yersinia spp. were analyzed. Overall, 5.747 tests were performed; only six were positive (0.1%). In four of these, Campylobacter spp. were detected; diarrhea started within 48 h after ICU admission. Two patients with Salmonella spp. detection were chronic shedders. On the contrary, testing for Clostridium difficile via GDH- and toxin A/B-EIA yielded positive results in 179/2209 (8.1%) tests and revealed 144/2.189 (6.6%) patients with clinically relevant C. difficile infection. CONCLUSIONS: Stool testing for enteric pathogens other than C. difficile should be avoided in ICU patients and is only reasonable when diarrhea commenced less than 48 h after hospital admission.

14.
Diagn Microbiol Infect Dis ; 89(4): 253-257, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28974396

RESUMEN

Given constantly high or even rising incidences of both colonization and infection with vancomycin-resistant enterococci (VRE), timely and accurate identification of carriers in high-risk patient populations is of evident clinical importance. In this study, a two-tier approach consisting of PCR-based screening and cultural confirmation of positive results is compared to the conventional approach solely based on culture on selective media. The 2-tier strategy was highly consistent with the conventional approach, and was found to possess high sensitivity and specificity (93.1% and 100%, respectively). The introduction of the PCR-based combined VRE screening approach significantly (P<0.0001) reduced median overall time to result by 44.3hours. The effect was found to be most pronounced in VRE negative samples. Positive vanA PCR was highly consistent with culture (PPV: 92.0%, 95% CI: 72.5-98.6%, NPV: 99.6%, 95% CI: 98.9-99.6%), thus allowing for preliminary reporting of VRE detection. In contrast, a vanB positive PCR does not allow for preliminary reporting (PPV: 58.5%, 95% CI: 44.2-71.6%, NPV: 99.8%, 95% CI: 99.2-100%). The introduction of a molecular assay for rapid detection of VRE from rectal swabs combined with cultural confirmation proved to be reliable and time saving, especially in a setting of low VRE prevalence and predominance of vanA positive strains.


Asunto(s)
Técnicas de Tipificación Bacteriana , Infecciones por Bacterias Grampositivas/diagnóstico , Enterococos Resistentes a la Vancomicina/aislamiento & purificación , Proteínas Bacterianas/genética , Ligasas de Carbono-Oxígeno/genética , Medios de Cultivo/química , Humanos , Reacción en Cadena de la Polimerasa , Recto/microbiología , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Enterococos Resistentes a la Vancomicina/clasificación
15.
PLoS One ; 12(9): e0182962, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28877205

RESUMEN

The fast and reliable characterization of bacterial and fungal pathogens plays an important role in infectious disease control and tracking of outbreak agents. DNA based methods are the gold standard for epidemiological investigations, but they are still comparatively expensive and time-consuming. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a fast, reliable and cost-effective technique now routinely used to identify clinically relevant human pathogens. It has been used for subspecies differentiation and typing, but its use for epidemiological tasks, e. g. for outbreak investigations, is often hampered by the complexity of data analysis. We have analysed publicly available MALDI-TOF mass spectra from a large outbreak of Shiga-Toxigenic Escherichia coli in northern Germany using a general purpose software tool for the analysis of complex biological data. The software was challenged with depauperate spectra and reduced learning group sizes to mimic poor spectrum quality and scarcity of reference spectra at the onset of an outbreak. With high quality formic acid extraction spectra, the software's built in classifier accurately identified outbreak related strains using as few as 10 reference spectra (99.8% sensitivity, 98.0% specificity). Selective variation of processing parameters showed impaired marker peak detection and reduced classification accuracy in samples with high background noise or artificially reduced peak counts. However, the software consistently identified mass signals suitable for a highly reliable marker peak based classification approach (100% sensitivity, 99.5% specificity) even from low quality direct deposition spectra. The study demonstrates that general purpose data analysis tools can effectively be used for the analysis of bacterial mass spectra.


Asunto(s)
Brotes de Enfermedades , Infecciones por Escherichia coli/microbiología , Escherichia coli Shiga-Toxigénica/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Estadística como Asunto , Biomarcadores/análisis
16.
J Antimicrob Chemother ; 72(9): 2483-2488, 2017 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-28637339

RESUMEN

Background: Avibactam is a novel broad-range ß-lactamase inhibitor active against Ambler class A (including ESBL and KPC) and some Ambler class C and D (e.g. OXA-48) enzymes. We here report on the emergence of ceftazidime/avibactam resistance in clinical, multiresistant, OXA-48 and CTX-M-14-producing Klebsiella pneumoniae isolate DT12 during ceftazidime/avibactam treatment. Methods and results: Comparative whole-genome sequence analysis identified two SNPs in the CTX-M-14-encoding gene leading to two amino acid changes (P170S and T264I). Compared with WT CTX-M-14, expression of the CTX-M-14Δ170Δ264 isoform in Escherichia coli led to a >64- and 16-fold increase in ceftazidime and ceftazidime/avibactam MICs, respectively, functionally linking the observed SNPs and elevated MICs. The mutated CTX-M-14 isoform exhibited augmented ceftazidime hydrolytic activity, which was a reasonable cause for impaired susceptibility to avibactam inhibition. The P170S exchange in CTX-M-14 was found in association with elevated ceftazidime/avibactam MICs for independent K. pneumoniae isolates, but was not sufficient for full resistance. Apparently, additional CTX-M-independent mechanisms contribute to ceftazidime/avibactam resistance in K. pneumoniae DT12. Conclusions: This study on the molecular basis of ceftazidime/avibactam resistance in clinical K. pneumoniae emerging in vivo underscores the need for continuous monitoring of ceftazidime/avibactam susceptibility during therapy. Despite sustained inhibition of OXA-48, rapid development of CTX-M-14 isoforms exhibiting augmented ceftazidime hydrolytic activity may limit the usefulness of ceftazidime/avibactam monotherapies in infections caused by isolates carrying blaCTX-M-14 and blaOXA-48.


Asunto(s)
Antibacterianos/farmacología , Compuestos de Azabiciclo/farmacología , Ceftazidima/farmacología , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/genética , Compuestos de Azabiciclo/administración & dosificación , Compuestos de Azabiciclo/uso terapéutico , Ceftazidima/administración & dosificación , Ceftazidima/uso terapéutico , Combinación de Medicamentos , Farmacorresistencia Bacteriana Múltiple , Genoma Bacteriano , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Infecciones por Klebsiella/tratamiento farmacológico , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/aislamiento & purificación , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Inhibidores de beta-Lactamasas/farmacología
17.
Infect Dis Rep ; 9(1): 6839, 2017 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-28458798

RESUMEN

Early availability of information on bacterial pathogens and their antimicrobial susceptibility is of key importance for the management of infectious diseases patients. Currently, using traditional approaches, it usually takes at least 48 hours for identification and susceptibility testing of bacterial pathogens. Therefore, the slowness of diagnostic procedures drives prolongation of empiric, potentially inappropriate, antibacterial therapies. Over the last couple of years, the improvement of available techniques (e.g. for susceptibility testing, DNA amplification assays), and introduction of novel technologies (e.g. MALDI-TOF) has fundamentally changed approaches towards pathogen identification and characterization. Importantly, these techniques offer increased diagnostic resolution while at the same time shorten the time-to-result, and are thus of obvious importance for antimicrobial stewardship. In this review, we will discuss recent advances in medical microbiology with special emphasis on the impact of novel techniques on antimicrobial stewardship programs.

18.
BMC Nephrol ; 18(1): 96, 2017 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-28320387

RESUMEN

BACKGROUND: Influenza A infections have been described to cause secondary hemolytic uremic syndrome and to trigger atypical hemolytic uremic syndrome (aHUS) in individuals with an underlying genetic complement dysregulation. To date, influenza B has not been reported to trigger aHUS. CASE PRESENTATION: A 6-month-old boy presented with hemolytic uremic syndrome triggered by influenza B infection. Initially the child recovered spontaneously. When he relapsed Eculizumab treatment was initiated, resulting in complete and sustained remission. A pathogenic mutation in membrane cofactor protein (MCP) was detected. CONCLUSION: Influenza B is a trigger for aHUS and might be underreported as such. Influenza vaccination may protect patients at risk.


Asunto(s)
Síndrome Hemolítico Urémico Atípico/diagnóstico , Síndrome Hemolítico Urémico Atípico/etiología , Virus de la Influenza B/aislamiento & purificación , Gripe Humana/complicaciones , Gripe Humana/diagnóstico , Síndrome Hemolítico Urémico Atípico/terapia , Diagnóstico Diferencial , Humanos , Lactante , Virus de la Influenza B/clasificación , Gripe Humana/terapia , Masculino , Resultado del Tratamiento
19.
BMC Infect Dis ; 16(1): 720, 2016 11 29.
Artículo en Inglés | MEDLINE | ID: mdl-27899074

RESUMEN

BACKGROUND: Staphylococcus aureus is among the most common pathogens isolated from blood cultures in Ghana; yet the epidemiology of blood infections in rural settings is poorly described. This study aims to investigate antimicrobial susceptibility and clonal diversity of S. aureus causing bloodstream infections in two hospitals in the Ashanti Region, Ghana. METHODS: Blood cultures were performed for all febrile patients (≥37.5 °C) on hospital admission. Antibiotic susceptibility testing for S. aureus isolates was carried out by the VITEK 2 system. Multiplex polymerase chain reaction (PCR) was used to detect S. aureus-specific nuc gene, Panton-Valentine leukocidin (PVL), and methicillin-resistant S. aureus (MRSA)-specific mecA and mecC genes. The population structure of S. aureus was assessed by spa typing. RESULTS: In total, 9,834 blood samples were cultured, out of which 0.6% (n = 56) were positive for S. aureus. Multidrug resistance (MDR) was detected in 35.7% (n = 20) of the S. aureus strains, of which one was a MRSA. The highest rate of antibiotic resistance was seen for commonly available antibiotics, including penicillin (n = 55; 98.2%), tetracycline (n = 32; 57.1%) and trimethoprim/sulfamethoxazole (n = 26; 46.4%). Of all S. aureus strains, 75.0% (n = 42) carried the PVL-encoding genes. We found 25 different spa types with t355 (n = 11; 19.6%), t314 (n = 8; 14.3%), t084 (n = 8; 14.3%) and t311 (n = 5; 8.9%) being predominant. CONCLUSION: The study exhibited an alarmingly large level of antibiotic resistance to locally available antibiotics. The frequency of genetically diverse and PVL-positive methicillin-sensitive S. aureus (MSSA) was high and could represent a reservoir for the emergence of virulent PVL-positive MRSA clones.


Asunto(s)
Antibacterianos/farmacología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética , Adolescente , Bacteriemia/microbiología , Proteínas Bacterianas/genética , Toxinas Bacterianas/genética , Niño , Preescolar , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple/genética , Exotoxinas/genética , Femenino , Variación Genética , Ghana , Hospitales , Humanos , Lactante , Recién Nacido , Leucocidinas/genética , Masculino , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Staphylococcus aureus Resistente a Meticilina/patogenicidad , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa Multiplex , Proteínas de Unión a las Penicilinas/genética , Población Rural , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/patogenicidad
20.
Int J Med Microbiol ; 306(6): 471-8, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27292911

RESUMEN

Biofilm-associated Staphylococcus epidermidis implant infections are notoriously reluctant to antibiotic treatment. Here we studied the effect of sub-inhibitory concentrations of penicillin, oxacillin, vancomycin, daptomycin, linezolid and tigecycline on S. epidermidis 1585 biofilm formation, expression of extracellular matrix binding protein (Embp) and potential implications for S. epidermidis - macrophage interactions. Penicillin, vancomycin, daptomycin, and linezolid had no biofilm augmenting effect at any of the concentrations tested. In contrast, at sub-inhibitory concentrations tigecycline and oxacillin exhibited significant biofilm inducing activity. In S. epidermidis 1585, SarA is a negative regulator of giant 1 MDa Embp, and down regulation of sarA induces Embp-dependent assembly of a multi-layered biofilm architecture. Dot blot immune assays, confocal laser scanning microscopy, and qPCR showed that under biofilm inducing conditions, tigecycline augmented embp expression compared to the control grown without antibiotics. Conversely, expression of regulator sarA was suppressed, suggesting that tigecycline exerts its effects on embp expression through SarA. Tigecycline failed to induce biofilm formation in embp transposon mutant 1585-M135, proving that under these conditions Embp up-regulation is necessary for biofilm accumulation. As a functional consequence, tigecycline induced biofilm formation significantly impaired the up-take of S. epidermidis by mouse macrophage-like cell line J774A.1. Our data provide novel evidence for the molecular basis of antibiotic induced biofilm formation, a phenotype associated with inherently increased antimicrobial tolerance. While this could explain failure of antimicrobial therapies, persistence of S. epidermidis infections in the presence of sub-inhibitory antimicrobials is additionally propelled by biofilm-related impairment of macrophage-mediated pathogen eradication.


Asunto(s)
Antibacterianos/metabolismo , Proteínas Bacterianas/biosíntesis , Biopelículas/crecimiento & desarrollo , Proteínas Portadoras/biosíntesis , Evasión Inmune , Minociclina/análogos & derivados , Staphylococcus epidermidis/efectos de los fármacos , Staphylococcus epidermidis/fisiología , Animales , Proteínas Bacterianas/genética , Proteínas Portadoras/genética , Línea Celular , Perfilación de la Expresión Génica , Humanos , Immunoblotting , Macrófagos/microbiología , Ratones , Microscopía Confocal , Minociclina/metabolismo , Fagocitosis , Reacción en Cadena en Tiempo Real de la Polimerasa , Staphylococcus epidermidis/inmunología , Staphylococcus epidermidis/metabolismo , Tigeciclina , Transactivadores/biosíntesis , Transactivadores/genética
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