RESUMEN
The immunosuppressive effect of methotrexate has rarely been associated with reactivation of cutaneous leishmaniasis. Here we present a case of a cutaneous leishmaniasis patient with atypical clinical symptoms without splenomegaly but with cutaneous manifestations after treatment of rheumatoid arthritis with methotrexate and blood recovery of the parasite. Next-generation sequencing was used to identify Leishmania infantum chagasi in the patient's blood sample.
Asunto(s)
Artritis Reumatoide , Leishmania infantum , Leishmaniasis Cutánea , Leishmaniasis Visceral , Artritis Reumatoide/complicaciones , Artritis Reumatoide/tratamiento farmacológico , Humanos , Leishmaniasis Cutánea/diagnóstico , Leishmaniasis Cutánea/tratamiento farmacológico , Leishmaniasis Cutánea/parasitología , Leishmaniasis Visceral/tratamiento farmacológico , Metotrexato/efectos adversosRESUMEN
Leishmaniasis is a major public health problem worldwide. Although next generation sequencing technology has been widely used in the diagnosis of infectious diseases, it has been scarcely applied in identification of Leishmania species. The aim of this study was to compare the efficiency of MinION™ nanopore sequencing and polymerase chain reaction restriction fragment length polymorphism in identifying Leishmania species. Our results showed that the MinION™ sequencer was able to discriminate reference strains and clinical samples with high sensitivity in a cost and time effective manner without the prior need for culture.
Asunto(s)
Leishmania , Leishmaniasis Cutánea , ADN Protozoario , Proteínas HSP70 de Choque Térmico/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Leishmania/genética , Leishmaniasis Cutánea/diagnóstico , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
Carbapenem-resistant Klebsiella pneumoniae (CRK) infections are a growing concern in immunocompromised patients. The aim of the present study was to evaluate the impact of CRK colonization and infection in overall mortality for haematopoietic stem-cell transplant (HSCT) patients. We also aimed to investigate resistance and virulence profiles of CRK isolates and assess their epidemiological and genetic relatedness. Patients in the HSCT unit were screened for colonization with CRK with weekly rectal swab or stool cultures and placed under contact precautions. We defined CRK colonization as positive culture from a swab or stool sample grown in MacConkey agar with meropenem at 1 µg ml-1. Demographic and clinical data were retrieved from the patients' charts and electronic records. According to resistance mechanisms and pulsed field gel electrophoresis profile, isolates were selected based on whole-genome sequencing (WGS) using MiSeq Illumina. Outcomes were defined as overall mortality (death up to D+100), and infection-related death (within 14 days of infection). We report a retrospective cohort of 569 haematopoietic stem-cell transplant patients with 105 (18.4â%) CRK colonizations and 30 (5.3â%) infections. blaKPC was the most frequent carbapenemase in our cohort with three isolates co-harbouring blaKPC and blaNDM. We found no difference in virulence profiles from the CRK isolates. There were also no significant differences in virulence profiles among colonization and infection isolates regarding genes encoding for type 1 and 3 fimbriae, siderophores, lipopolysaccharide and colibactin. In clonality analysis by PFGE and WGS, isolates were polyclonal and ST340 was the most prevalent. Overall survival at D+100 was 75.4â% in in CRK-colonized (P=0.02) and 35.7â% in infected patients and significantly lower than non-colonized patients (85.8â%; P<0.001). We found a higher overall mortality associated with colonization and infection; KPC was the main resistance mechanism for carbapenems. The polyclonal distribution of isolates and findings of CRK infection in patients not previously colonized suggest the need to reinforce antibiotic stewardship.
Asunto(s)
Enterobacteriaceae Resistentes a los Carbapenémicos/aislamiento & purificación , Trasplante de Células Madre Hematopoyéticas/mortalidad , Infecciones por Klebsiella , Adolescente , Adulto , Anciano , Farmacorresistencia Bacteriana , Femenino , Humanos , Infecciones por Klebsiella/etiología , Infecciones por Klebsiella/microbiología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Virulencia , Adulto JovenRESUMEN
The treatment of infections caused by A. baumannii is a challenge and fosfomycin has been used as a combination therapy. Moreover, data regarding the fosfomycin resistance mechanism is scarce. The goals of this study were to evaluate fosfomycin susceptibility in polyclonal multi-resistant A. baumannii isolates and characterize the fosfomycin resistance. We analyzed 32 A. baumannii isolates from a Brazilian bacterial collection, followed by their minimum inhibitory concentration (MIC), and whole-genome sequence to detect fosfomycin resistance genes. The isolates showed a fosfomycin MIC ranging from 32 to ≥256 mg/L. All isolates were negative for fosA and fosB genes, and four isolates carried the fosX gene. Two different metabolic pathways that form peptidoglycan precursors were identified. Mutations were observed in the adenylate cyclase gene. All A. baumannii isolates studied showed Val132Ala substitutions in MurA. The analysis showed different ways that may lead to the intrinsic fosfomycin-resistance of A. baumannii, such as alterations on the glycerol-3-phosphate transporter system caused by adenylate cyclase mutations; and a possible connection of cell wall recycling by different metabolic pathways.
Asunto(s)
Infecciones por Acinetobacter/microbiología , Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Fosfomicina/farmacología , Humanos , Pruebas de Sensibilidad MicrobianaRESUMEN
Treatment of infections caused by A. baumannii is becoming a challenge due to the ability to develop multidrug-resistance, virulence, and high mortality. We described the colistin resistance and virulence genes present in sixA. baumannii clinical isolates using WGS, expression by qPCR, and virulence in the Galleria mellonella model. The colistin-resistant isolates were assigned as ST233 and the colistin-susceptible isolates as ST236 and ST407. The colistin-resistant isolates contained mutations within PmrA/PmrB, and the pmrA showed up-regulation in all of them. Only one colistin-resistant isolate indicating virulence in G. mellonella. This particular isolate belonged to a different clone, and it was the only isolate that presented non-synonymous mutations in pmrB. Colistinresistance in A. baumannii isolates seems to be caused by up-regulation of pmrA gene. Only one isolate appeared to be virulent in the G. mellonella model. This finding indicating low virulence in isolates belonging to emerging clones circulating in our hospital.
Asunto(s)
Acinetobacter baumannii/genética , Acinetobacter baumannii/patogenicidad , Antibacterianos/farmacología , Colistina/farmacología , Farmacorresistencia Bacteriana/genética , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/efectos de los fármacos , Animales , Proteínas Bacterianas/genética , Modelos Animales de Enfermedad , Regulación Bacteriana de la Expresión Génica , Genoma Bacteriano/genética , Humanos , Pruebas de Sensibilidad Microbiana , Mariposas Nocturnas , Mutación , Factores de Transcripción/genética , Virulencia/genéticaRESUMEN
Susceptibility of ceftazidime-avibactam and in vitro synergy with meropenem were investigated using disk approximation and time-kill assays against 11 multiresistant Acinetobacter baumannii isolates harboring oxacillinases and 5 Serratia marcescens isolates carrying blaKPC-2 Ceftazidime-avibactam was very active and synergistic with meropenem against multiresistant S. marcescens isolates. On the other hand, only the A. baumannii isolates coharboring blaOXA-23 and blaOXA-117 displayed synergy. The disk approximation technique presented good sensitivity for synergism in S. marcescens infection.
Asunto(s)
Antibacterianos/farmacología , Compuestos de Azabiciclo/farmacología , Proteínas Bacterianas/metabolismo , Ceftazidima/farmacología , Meropenem/farmacología , beta-Lactamasas/metabolismo , Acinetobacter baumannii/efectos de los fármacos , Proteínas Bacterianas/genética , Combinación de Medicamentos , Pruebas de Sensibilidad Microbiana , Serratia marcescens/efectos de los fármacos , beta-Lactamasas/genéticaRESUMEN
OBJECTIVES: Based on pulsed-field gel electrophoresis (PFGE) profile, whole-genome sequencing (WGS) of eight carbapenem-resistant Pseudomonas aeruginosa isolates from a bone marrow transplant unit in São Paulo, Brazil, was performed to investigate the presence of resistance and virulence genes as well as to determine the sequence type (ST) by multilocus sequence typing (MLST). METHODS: The initial phenotypic susceptibility pattern of the isolates was determined by VITEK®2. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method for amikacin, meropenem and colistin. WGS was performed using an Illumina MiSeq system. A Galleria mellonella infection model was used to evaluate the virulence of the strains. RESULTS: WGS demonstrated that mutations in genes encoding outer membrane proteins and efflux pumps in an isolate harbouring blaVIM-36 (ST308) differed from those in isolates harbouring blaSPM (ST277). The mexT gene harboured a mutation resulting in a frameshift in all isolates; in addition, the oprD gene of the blaVIM-36-carrying isolate had an insertion leading to a frameshift. Virulence genes did not differ between ST277 and ST308 strains. Moreover, only two isolates harbouring blaSPM showed virulence in the G. mellonella model, killing 100% of larvae after 18-24h. CONCLUSIONS: P. aeruginosa carrying blaVIM-36 belonging to ST308 was identified for the first time in our hospital. Although the virulence gene profiles were similar in isolates carrying blaSPM and the isolate carrying blaVIM-36, only two isolates harbouring blaSPM showed virulence in the G. mellonella model.