RESUMEN
This article describes positive (1 â 3)-ß-D-glucan levels in serum from infants with primary Pneumocystis infection and from immunosuppressed patients with Pneumocystis pneumonia (PCP) and negative levels in serum from patients colonized by Pneumocystis jirovecii. Glucan detection is a complementary tool for the diagnosis of the diverse clinical presentations of P. jirovecii infection.
Asunto(s)
Biomarcadores/sangre , Infecciones por Pneumocystis/diagnóstico , beta-Glucanos/sangre , Portador Sano/diagnóstico , Femenino , Humanos , Lactante , Enfermedades Pulmonares Fúngicas/diagnóstico , Masculino , Pneumocystis carinii/aislamiento & purificación , Proteoglicanos , Suero/químicaRESUMEN
Forty-seven non-epidemic Escherichia coli O157 : H7 isolates causing haemolytic uraemic syndrome in France were characterized. The isolates clustered into 36 clones using PFGE typing. All the isolates harboured eae and one or more copies of stx2 and belonged to phylogenetic group D. Nine per cent were resistant to amoxicillin.
Asunto(s)
Infecciones por Escherichia coli/microbiología , Escherichia coli O157/aislamiento & purificación , Síndrome Hemolítico-Urémico/microbiología , Adhesinas Bacterianas/genética , Adulto , Amoxicilina/farmacología , Antibacterianos/farmacología , Niño , Análisis por Conglomerados , Dermatoglifia del ADN , ADN Bacteriano/análisis , Farmacorresistencia Bacteriana , Electroforesis en Gel de Campo Pulsado , Escherichia coli O157/efectos de los fármacos , Escherichia coli O157/genética , Proteínas de Escherichia coli/genética , Heces/microbiología , Francia , Genes Bacterianos , Humanos , Epidemiología Molecular , Filogenia , Polimorfismo de Longitud del Fragmento de Restricción , Toxina Shiga II/genéticaRESUMEN
We report a cluster of pediatric diarrhea due to Shigella dysenteriae serotype 1 involving 11 children in France, including the index case, who had returned from Senegal. Child-to-child transmission was documented by ribotyping. Five children developed hemolytic uremic syndrome (HUS). On the basis of our findings, the choice of antimicrobial treatment for infections with S. dysenteriae serotype 1 should take into account widespread drug resistance and the risk of HUS.
Asunto(s)
Disentería Bacilar/complicaciones , Síndrome Hemolítico-Urémico/etiología , Shigella dysenteriae , Antibacterianos/farmacología , Niño , Preescolar , Diarrea/complicaciones , Farmacorresistencia Bacteriana , Femenino , Francia , Síndrome Hemolítico-Urémico/epidemiología , Humanos , Lactante , Masculino , Factores de Riesgo , Shigella dysenteriae/efectos de los fármacosRESUMEN
BACKGROUND: Three-day, 10 mg/kg/day azithromycin (AZM) studies in pediatric acute group A streptococcal tonsillopharyngitis have shown contradictory bacteriologic results. This study investigates the efficacy and tolerability of two dosages of 3-day azithromycin (20 mg/kg/day and 10 mg/kg/day) compared with 10-day penicillin V. METHODS: This was a prospective, comparative, randomized, multicenter trial. Children were scheduled to return for visits at 14 days (main end point) and 1 month after the onset of treatment for clinical and bacteriologic assessment. Molecular tools were used to compare pre- and posttreatment group A beta-hemolytic Streptococcus (GABHS) isolates. RESULTS: Between November, 1997, and July, 1998, 501 patients (169 AZM 10 mg, 165 AZM 20 mg, 167 penicillin V) between 2 and 12 years old were enrolled; 500 were assessable for safety, 469 for intent to treat analysis and 420 for efficacy in the per protocol analysis. Before treatment 25 (7.9%) of 315 GABHS stains isolated from patients receiving AZM were resistant to this compound. On Day 14 pretreatment GABHS were eradicated from 78 (57.8%) of the 135 children receiving the AZM 10 mg regimen, 131 (94.2%) of the 139 receiving AZM 20 mg and 123 (84.2%) of the 146 taking penicillin. One month after the outset of treatment, bacteriologic relapses were observed in 40.5% (n = 30) of the children receiving AZM 10 mg, 14.8% (n = 18) of children taking AZM 20 mg and 13.2% (n = 15) of those treated with penicillin V. AZM 20 mg/kg/day was statistically superior to AZM 10 mg/kg/day microbiologically on Day 14 (P = 0.0001) and Day 30 (P = 0.0001) and clinically on Day 14 (P = 0.0035). AZM 20 mg/kg/day was statistically equivalent both microbiologically and clinically to standard therapy with penicillin V at all endpoints. The incidence of treatment-related adverse events was similar in the two azithromycin groups [AZM 10 mg, 31 of 169 (18.3%); AZM 20 mg, 37 of 164 (23%)] but significantly higher than those observed in the penicillin V group [5 of 166 (3%); P < 0.0001]. Most treatment-related adverse events were gastrointestinal and of mild-to-moderate severity. Fourteen patients withdrew from the trial because of adverse events (1 in the penicillin V group, 7 in the AZM 10 mg group and 6 in the AZM 20 mg group). CONCLUSION: This is the first study to demonstrate a daily dose-dependent difference in microbiologic efficacy of a regimen; 3-day AZM 20 mg/kg/day is a more effective regimen than 3-day AZM 10 mg/kg/day for pediatric GABHS tonsillopharyngitis.
Asunto(s)
Antibacterianos/administración & dosificación , Antibacterianos/farmacología , Azitromicina/administración & dosificación , Azitromicina/farmacología , Penicilina V/administración & dosificación , Penicilina V/farmacología , Penicilinas/administración & dosificación , Penicilinas/farmacología , Faringitis/tratamiento farmacológico , Infecciones Estreptocócicas/tratamiento farmacológico , Streptococcus pyogenes/patogenicidad , Tonsilitis/tratamiento farmacológico , Administración Oral , Antibacterianos/efectos adversos , Azitromicina/efectos adversos , Niño , Preescolar , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Humanos , Lactante , Masculino , Faringitis/microbiología , Estudios Prospectivos , Infecciones Estreptocócicas/patología , Tonsilitis/microbiología , Resultado del TratamientoRESUMEN
We investigated the dissemination of pathogenicity island (PAI) II(J96)-like elements (hra, hly, cnf1, and pap) among 455 Escherichia coli isolates from children and adults with urinary tract infection (UTI), neonates with meningitis or colonized healthy neonates, and 74 reference strains by means of PCR phylogenetic grouping, ribotyping, and PCR analysis of virulence genes. Colocalization of these genes was documented by pulsed-field gel electrophoresis followed by Southern hybridization and long-range PCR (LRPCR) between the hra and the papG alleles. Site-specific insertion of the PAI was determined by LRPCR between hra and tRNA flanking sequences. hra, hly, and cnf1 were found in 113 isolates and consistently colocalized, constituting the backbone of PAI II(J96)-like domains. The prevalence of PAI II(J96)-like domains was significantly higher among UTI isolates than among neonatal meningitis and commensal isolates. These domains were restricted to a few ribotypes of group B2. In contrast to the consistent colocalization of hra, hly, and cnf1, the pap operon was varied: 12% of strains exhibited an allelic exchange of the papG class III allele (papGIII) for the papG class II allele (papGII) (only UTI isolates), and the pap operon was deleted in 23% of strains. No strains harbored papGIII outside the PAI, which appears to be the only source of this allele. PAI II(J96)-like domains were inserted in the vicinities of three different tRNAs--pheU (54%), leuX (29%), and pheV (15%)--depending on the genetic backgrounds and origins of the isolates. Multiple insertional events restricted by the genetic background have thus led to PAI II(J96) acquisition. Specific genetic backgrounds and insertion sites may have played a role in additional recombination processes for E. coli adaptation to different ecological niches.
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Escherichia coli/patogenicidad , Adhesinas de Escherichia coli/genética , Adulto , Niño , Preescolar , Escherichia coli/genética , Proteínas Fimbrias/genética , Islas Genómicas , Humanos , Lactante , Reacción en Cadena de la Polimerasa , Ribotipificación , Infecciones Urinarias/microbiologíaRESUMEN
We describe in vivo selection of a Klebsiella pneumoniae strain with diminished imipenem susceptibility attributable to plasmid-encoded ACC-1 beta-lactamase production and loss of a 36-kDa major outer membrane protein, together with transfer of this plasmid from K. pneumoniae to Escherichia coli in a Tunisian infant.
Asunto(s)
Proteínas Bacterianas/genética , Conjugación Genética , Escherichia coli/efectos de los fármacos , Klebsiella pneumoniae/efectos de los fármacos , Plásmidos/genética , beta-Lactamasas/genética , Antibacterianos/farmacología , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Escherichia coli/enzimología , Escherichia coli/genética , Infecciones por Escherichia coli/microbiología , Humanos , Imipenem/farmacología , Lactante , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/genética , Masculino , Pruebas de Sensibilidad Microbiana , Selección Genética , Resistencia betalactámica/genéticaRESUMEN
The mechanisms of resistance to macrolides in seven group A streptococcal (Streptococcus pyogenes) isolates that were the cause of pharyngitis in children who were unsuccessfully treated with azithromycin (10 mg/kg of body weight/day for 3 days) were evaluated. All posttreatment strains were found to be genetically related to the pretreatment isolates by random amplified polymorphism DNA analysis and pulsed-field gel electrophoresis. Two isolates had acquired either a mef(A) or an erm(B) gene, responsible for macrolide efflux and ribosomal modification, respectively. Three isolates displayed mutations in the gene encoding the L4 ribosomal protein that is part of the exit tunnel within the 50S subunit of the bacterial ribosome. In the two remaining posttreatment strains, the mechanisms of macrolide resistance could not be elucidated.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana/genética , Faringitis/microbiología , Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes/efectos de los fármacos , Niño , Preescolar , ADN Bacteriano/análisis , Electroforesis en Gel de Campo Pulsado , Humanos , Macrólidos , Pruebas de Sensibilidad Microbiana , Técnica del ADN Polimorfo Amplificado Aleatorio , Proteínas Ribosómicas/genética , Streptococcus pyogenes/genéticaRESUMEN
We studied the telithromycin, erythromycin, azithromycin, and clindamycin susceptibilities of serotype III macrolide-resistant group B streptococci, together with genetic mechanisms of resistance and genomic diversity. ermB, ermA, and mefA were found in, respectively, 57, 32, and 9% of isolates. The telithromycin MIC at which 90% of isolates were inhibited was 0.5 micro g/ml. Macrolide resistance was associated with dissemination of resistance determinants among isolates of different genetic backgrounds.
Asunto(s)
Antibacterianos/farmacología , Cetólidos , Macrólidos/farmacología , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/efectos de los fármacos , Streptococcus agalactiae/genética , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana , Eritromicina/farmacología , Femenino , Genes Bacterianos/genética , Humanos , Recién Nacido , Proteínas de la Membrana/genética , Metiltransferasas/genética , Pruebas de Sensibilidad Microbiana , Embarazo , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
We studied a collection of 110 serotype III group B streptococcus (GBS) isolates causing neonatal meningitis, by means of both pulsed-field gel electrophoresis (PFGE) with SmaI and Southern hybridization with probes for genes potentially associated with virulence (neuA, cpsA, scpB, and hylB and, for mobile genetic elements [MGEs], GBSi1 and IS1548), in comparison with 44 serotype III GBS isolates colonizing healthy neonates. Using polymerase chain reaction, we assessed both the insertion of MGEs downstream of the scpB gene and the insertion of IS1548 within the hylB gene. PFGE clustered the isolates into 3 main groups. One PFGE group accounted for 80% of typeable cerebrospinal fluid (CSF) isolates, versus 24% of colonization isolates (P=1.8 x 10-9). GBSi1 was found in 67% of CSF isolates and in only 23% of colonization isolates (P=5.3 x 10-7). A 15-kbp SmaI restriction-DNA fragment bearing the neuA gene was significantly associated with CSF isolates (P=1.1 x 10-11).
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Técnicas de Tipificación Bacteriana , Meningitis Bacterianas/microbiología , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/genética , Proteínas Bacterianas/genética , Southern Blotting , Líquido Cefalorraquídeo/microbiología , Elementos Transponibles de ADN/genética , Desoxirribonucleasas de Localización Especificada Tipo II , Electroforesis en Gel de Campo Pulsado , Humanos , Recién Nacido , Reacción en Cadena de la Polimerasa , Serotipificación , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/aislamiento & purificación , Streptococcus agalactiae/patogenicidad , VirulenciaRESUMEN
We compared the activities of telithromycin, erythromycin, azithromycin, josamycin, penicillin G, amoxicillin, cefpodoxime, and ceftriaxone against invasive and noninvasive non-penicillin-susceptible Streptococcus pneumoniae isolates recovered from children. Of the 186 isolates tested, 89% were positive for erm(B) by PCR. Telithromycin had the lowest MICs, with MICs at which 90% of the isolates tested are inhibited of 0.032 and 0.25 micro g/ml for erythromycin-sensitive and -resistant isolates, respectively.
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Antibacterianos/farmacología , Ceftizoxima/análogos & derivados , Cetólidos , Macrólidos , Infecciones Neumocócicas/tratamiento farmacológico , Streptococcus pneumoniae/efectos de los fármacos , Amoxicilina/farmacología , Azitromicina/farmacología , Ceftizoxima/farmacología , Ceftriaxona/farmacología , Niño , Farmacorresistencia Bacteriana , Eritromicina/farmacología , Francia , Humanos , Técnicas In Vitro , Josamicina/farmacología , Penicilina G/farmacología , Resistencia a las Penicilinas , Penicilinas/farmacología , CefpodoximaRESUMEN
We report that the archetypal Escherichia coli strain C5 causing neonatal meningitis harbors a pathogenicity island (PAI) designated PAI I(C5) that is similar to the PAI II(J96) of uropathogenic E. coli J96 inserted in the leuX-tRNA gene. PAI-negative C5 mutants had a lower capacity than C5 to induce high-level bacteremia in a neonatal rat model. However, no change in their resistance to the bactericidal effect of serum and their capacity to cross the blood-brain barrier was observed.
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Escherichia coli/genética , Escherichia coli/patogenicidad , Meningitis por Escherichia coli/microbiología , Animales , Bacteriemia/microbiología , Secuencia de Bases , Actividad Bactericida de la Sangre , ADN Bacteriano/genética , Modelos Animales de Enfermedad , Infecciones por Escherichia coli/microbiología , Genes Bacterianos , Humanos , Recién Nacido , Datos de Secuencia Molecular , Ratas , Ratas Sprague-Dawley , Eliminación de Secuencia , Virulencia/genéticaRESUMEN
We studied the antimicrobial susceptibility of 322 Streptococcus pyogenes throat isolates from French children and their serotype and genomic diversity. A total of 22.4% were erythromycin resistant, and 69.4, 4.2, and 26.4% of these isolates harbored ermB, ermA, and mefA, respectively. Increasing resistance in France is mainly associated with a few emm type 28 clones.
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Antibacterianos/farmacología , Macrólidos/farmacología , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes/efectos de los fármacos , Adolescente , Proteínas Bacterianas/genética , Niño , Preescolar , ADN Bacteriano/genética , Farmacorresistencia Bacteriana , Electroforesis en Gel de Campo Pulsado , Francia/epidemiología , Genoma Bacteriano , Humanos , Proteínas de la Membrana/genética , Metiltransferasas/genética , Pruebas de Sensibilidad Microbiana , Faringitis/microbiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Serotipificación , Streptococcus pyogenes/genéticaRESUMEN
We characterized 100 Escherichia coli urosepsis isolates from adult patients according to host compromise status by means of ribotyping, PCR phylogenetic grouping, and PCR detection of papG alleles and the virulence-related genes sfa/foc, fyuA, irp-2, aer, hly, cnf-1 and hra. We also tested these strains for copies of pap and hly and their direct physical linkage with other virulence genes in an attempt to look for pathogenicity islands (PAIs) described for the archetypal uropathogenic strains J96, CFT073, and 536. Most of the isolates belonged to E. coli phylogenetic groups B2 and D and bore papG allele II, aer, and fyuA/irp-2. papG allele II-bearing strains were more common in noncompromised patients, while papG allele-negative strains were significantly more frequent in compromised patients. Fifteen ribotypes were identified. The three archetypal strains harbored different ribotypes, and only one-third of our urosepsis strains were genetically related to one of the archetypal strains. Three and 18 strains harbored three and two copies of pap, respectively, and 5 strains harbored two copies of hly. papGIII was physically linked to hly, cnf-1, and hra (reported to be PAI II(J96)-like genetic elements) in 14% of the strains. The PAI II(J96)-like domain was inserted within pheR tRNA in 11 strains and near leuX tRNA in 3 strains. Moreover, the colocalized genes cnf-1, hra, and hly were physically linked to papGII in four strains and to no pap gene in three strains. papGII and hly (reported to be PAI I(CFT073)-like genetic elements) were physically linked in 16 strains, pointing to a PAI I(CFT073)-like domain. Three strains contained both a PAI II(J96)-like domain and a PAI I(CFTO73)-like domain. Forty-two strains harbored papGII but not hly, in keeping with the presence of a PAI II(CFT073)-like domain. Only one strain harbored a PAI I(536)-like domain (hly only), and none harbored a PAI I(J96)-like domain (papGI plus hly) or a PAI II(536)-like domain (papGIII plus hly). This study provides new data on the prevalence and variability of physical genetic linkage between pap and certain virulence-associated genes that are consistent with their colocalization on archetypal PAIs.
Asunto(s)
Bacteriemia/microbiología , Proteínas Bacterianas , Infecciones por Escherichia coli/microbiología , Escherichia coli/genética , Proteínas Fimbrias , Pielonefritis/microbiología , Adhesinas de Escherichia coli/genética , Adulto , Anciano , Anciano de 80 o más Años , Alelos , Bacteriemia/epidemiología , Proteínas de la Membrana Bacteriana Externa/genética , Toxinas Bacterianas/genética , Proteínas Portadoras/genética , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/microbiología , Citotoxinas/genética , Escherichia coli/clasificación , Infecciones por Escherichia coli/epidemiología , Proteínas de Escherichia coli/genética , Femenino , Francia/epidemiología , Genes Bacterianos , Humanos , Péptidos y Proteínas de Señalización Intercelular , Masculino , Persona de Mediana Edad , Filogenia , Prevalencia , Pielonefritis/epidemiología , Receptores de Superficie Celular/genética , Recombinación Genética , Ribotipificación , Sepsis/microbiología , VirulenciaRESUMEN
Phylogenetic relationships, virulence factors, alone and in specific combinations, and virulence in a rat meningitis model were examined among 132 isolates of Escherichia coli neonatal meningitis from France and North America. Isolates belonging to phylogenetic groups A (n=11), D (n=20), and B2 (n=99) had similar high prevalence rates of the siderophores aerobactin and yersiniabactin and the K1 capsule (>/=70%) yet induced different level of experimental bacteremia. Ectochromosomal DNA-like domains involved in blood-brain barrier passage (PAI III(536) [sfa/foc and iroN; 34%]; GimA [ibeA and ptnC; 38%]; PAI II(J96) [hly, cnf1, and hra; 10%]) were restricted to B2 isolates. Among group B2 isolates, representatives of the O45:K1 clonal group (n=30), which lacked these domains, were as able as the archetypal O18:K1 strain C5 to cause meningitis. Molecular epidemiology combined with experimental virulence assays demonstrate that known virulence factors are insufficient to fully explain the pathophysiology of ECNM and to allow for rational search for new virulence factors.