RESUMEN
The prevalence of bla CTX-M, bla TEM and bla SHV genes among extended-spectrum beta-lactamase (ESBL)-producing clinical isolates of Escherichia coli (n = 50) and Klebsiella spp. (n = 50) from Lebanon was 96%, 57% and 67%, and 40%, 82% and 84%, respectively. Genotyping revealed that the clonal diversity was unrelated to the presence of bla genes. Sequence analysis of 16 selected isolates identified the bla CTX-M-15, bla TEM-1, bla OXA-1 and six bla SHV genes, as well as the gene encoding the quinolone-modifying enzyme AAC(6')-Ib-cr. The genes encoding CTX-M-15 and AAC(6')-Ib-cr were carried on a 90-kb plasmid of the pC15-1a or pCTX-15 type, which transferred both ESBL production and quinolone resistance from donors to transconjugants.
Asunto(s)
Escherichia coli/genética , Klebsiella/genética , beta-Lactamasas/genética , Infección Hospitalaria/microbiología , Infecciones por Enterobacteriaceae/microbiología , Escherichia coli/enzimología , Infecciones por Escherichia coli/microbiología , Genotipo , Humanos , Klebsiella/enzimología , LíbanoRESUMEN
The emergence in Shigella species of extended-spectrum beta-lactamases (ESBL) that impart resistance to third-generation cephalosporins is a growing concern world-wide. So far, however, ESBL-producing Shigella have only been reported seven times, albeit from seven different countries. In Lebanon, three ESBL-producing clinical isolates of S. sonnei were recovered from 30 cases of shigellosis diagnosed between July 2004 and October 2005. All three were found to be resistant to amoxycillin, cefotaxime, ceftazidime, aztreonam, trimethoprim/sulphamethoxazole, gentamicin, and kanamycin. Each harboured the bla-CTX-M gene, and the results of sequence analysis indicated this to be of the bla-CTX-M-15 type and encoded on a 70-kb plasmid, flanked by an insertion element (ISEcp1). The bla-TEM-1 gene was also detected on the chromosomes of two of the ESBL-producing isolates. Class-2 integrons containing dhfr1, aadA1 and sat1 genes were detected on the chromosomes of all three isolates but not on the plasmids. Fluoroquinolone-modifying factors [QnrA, QnrB, QnrS or AAC(6')-Ib-cr] were not detected. The results of RAPD analysis, combined with data on antimicrobial susceptibility, indicated that each isolate was unique. In conclusion, the emergence of ESBL-producing isolates of S. sonnei has been demonstrated for the first time in Lebanon. The resistance of these isolates to third-generation cephalosporins was mediated by the CTX-M-15 enzyme, which was plasmid-encoded.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana/genética , Disentería Bacilar/parasitología , Shigella sonnei/genética , beta-Lactamasas/genética , Animales , Niño , Preescolar , ADN Bacteriano/genética , Disentería Bacilar/tratamiento farmacológico , Humanos , Líbano , Reacción en Cadena de la Polimerasa , Análisis de Secuencia , Shigella sonnei/efectos de los fármacos , Shigella sonnei/aislamiento & purificación , beta-Lactamasas/metabolismoRESUMEN
Bacterial peritonitis is a well-recognized complication of chronic ambulatory peritoneal dialysis (CAPD) in patients with end-stage renal failure. We present a case of peritonitis due to an unusual pathogen, Neisseria cinerea, unresponsive to the standard intraperitoneal (i.p.) vancomycin and gentamicin, which responded rapidly to oral ciprofloxacin.
Asunto(s)
Antibacterianos/uso terapéutico , Ciprofloxacina/uso terapéutico , Fallo Renal Crónico/complicaciones , Neisseria cinerea/aislamiento & purificación , Infecciones por Neisseriaceae/microbiología , Diálisis Peritoneal Ambulatoria Continua/efectos adversos , Peritonitis/microbiología , Adulto , Gentamicinas/uso terapéutico , Humanos , Masculino , Infecciones por Neisseriaceae/tratamiento farmacológico , Peritonitis/tratamiento farmacológico , Vancomicina/uso terapéuticoAsunto(s)
Farmacorresistencia Bacteriana/genética , Gonorrea/tratamiento farmacológico , Neisseria gonorrhoeae/efectos de los fármacos , Antiinfecciosos/farmacología , Ciprofloxacina/farmacología , ADN Bacteriano/genética , Genotipo , Gonorrea/microbiología , Humanos , Neisseria gonorrhoeae/genética , Insuficiencia del TratamientoRESUMEN
Ciprofloxacin-resistant Neisseria gonorrhoeae had been rarely detected on Merseyside and when found was associated with beta-lactamase producing strains, imported from abroad. However, in August 2000, two cases of infection with ciprofloxacin-resistant beta-lactamase-negative strains occurred in sexually unrelated patients with no history of foreign travel. Over the next 18 months a total of 120 patients presented with ciprofloxacin-resistant gonococci, from which 99 patient strains were available for study. Gonococcal DNA was subjected to molecular fingerprinting by polymerase chain reaction amplification followed by Taq1 digestion of their opa genes. Twelve differing opa-types were found, but 79 patients were infected with a single genotype, opa-type 1. The sexual histories of the majority of this group indicated acquisition in Merseyside. This endemic strain was further characterized by having the same amino acid substitutions on gyrA and parC genes. An endemic clone of ciprofloxacin-resistant N. gonorrhoeae has been established on Merseyside necessitating the introduction of ceftriaxone as first-line treatment. Despite the presence of 11 other clones in the city, opa type-1 strains have not yet been displaced, raising the possibility that this strain is endowed with added virulence/endemicity traits or that a number of source patients have not yet been found.
Asunto(s)
Antiinfecciosos , Ciprofloxacina , Enfermedades Endémicas/estadística & datos numéricos , Gonorrea/epidemiología , Gonorrea/microbiología , Epidemiología Molecular , Neisseria gonorrhoeae/genética , Sustitución de Aminoácidos/genética , Antibacterianos/uso terapéutico , Proteínas de la Membrana Bacteriana Externa/genética , Ceftriaxona/uso terapéutico , Dermatoglifia del ADN , Girasa de ADN/genética , Topoisomerasa de ADN IV/genética , ADN Bacteriano/análisis , ADN Bacteriano/genética , Farmacorresistencia Bacteriana/genética , Electroforesis en Gel de Campo Pulsado , Inglaterra/epidemiología , Femenino , Gonorrea/tratamiento farmacológico , Humanos , Masculino , Anamnesis , Pruebas de Sensibilidad Microbiana , Neisseria gonorrhoeae/clasificación , Mutación Puntual/genética , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , SerotipificaciónRESUMEN
Neisseria weaveri (formerly CDC [Centers for Disease Control and Prevention] group M-5 is part of the normal canine oral flora. Infections in humans are usually associated with dog bite wounds. Very rarely the organism has been isolated from sites other than wounds, or from deep seated infections. A 60-year-old man was admitted to our hospital because of an acute exacerbation of his bronchiectasis. Gram stain of bronchial washings and expectorated sputum showed numerous polymorphs and Gram-negative bacilli. Routine bacterial culture yielded a heavy pure growth of a Gram-negative rod-shaped organism that was strongly oxidase and catalase positive, indole negative, non-motile and did not ferment carbohydrates. The organism was identified as N. weaveri by using 16S rRNA sequencing. The patient was treated with a 3 weeks course of ofloxacin and had a good response. Sputum culture after treatment yielded normal respiratory flora only. To our knowledge, this is the first reported case of lower respiratory tract infection caused by N. weaveri.
Asunto(s)
Infecciones por Bacterias Gramnegativas/microbiología , Neisseria/aislamiento & purificación , Infecciones del Sistema Respiratorio/microbiología , Animales , Mordeduras y Picaduras/microbiología , Perros , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Neisseria/genética , ARN Ribosómico 16S/genética , Infecciones del Sistema Respiratorio/tratamiento farmacológicoRESUMEN
Colonisation with Pseudomonas aeruginosa is common in adults with cystic fibrosis (CF) and there is increasing evidence that transmissible strains may cross colonise patients. However, transmission of these strains by social contact to healthy non-CF individuals has not been described. A case is presented where an adult CF patient colonised by an epidemic P aeruginosa strain infected her parents with subsequent morbidity.
Asunto(s)
Infección Hospitalaria/transmisión , Fibrosis Quística/microbiología , Infecciones por Pseudomonas/transmisión , Adulto , Fibrosis Quística/complicaciones , Farmacorresistencia Bacteriana Múltiple , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Pseudomonas aeruginosa/efectos de los fármacosRESUMEN
We report three fatal cases of bacteremia (two adults, one neonate) caused by Vibrio cholerae O1 (Ogawa), which occurred in the context of a community outbreak of cholera diarrhea in Blantyre, Malawi. Only four cases of invasive disease caused by V. cholerae O1 have previously been reported. We describe the clinical features associated with these rare cases and discuss their significance.
Asunto(s)
Bacteriemia/microbiología , Proteínas Bacterianas , Cólera/microbiología , Diarrea/microbiología , Brotes de Enfermedades , Anciano , Bacteriemia/epidemiología , Bacteriemia/fisiopatología , Cólera/epidemiología , Cólera/fisiopatología , Toxina del Cólera/genética , Proteínas de Unión al ADN/genética , Diarrea/epidemiología , Diarrea/fisiopatología , Resultado Fatal , Femenino , Genoma Bacteriano , Humanos , Recién Nacido , Malaui/epidemiología , Masculino , Persona de Mediana Edad , Factores de Transcripción/genética , Vibrio cholerae/clasificación , Vibrio cholerae/genética , Vibrio cholerae/aislamiento & purificaciónRESUMEN
Nine Klebsiella pneumoniae isolates, six from blood and three from cerebrospinal fluid of newborn babies at Kenyatta National Hospital, Nairobi, Kenya, were analyzed for the mechanism of cephalosporin resistance. By using pulsed-field gel electrophoresis of XbaI-digested chromosomal DNA, all the nine isolates were found to be clonal. PCR and direct sequencing revealed a novel extended-spectrum beta-lactamase, which we designated CTX-M-12. It has a more potent hydrolytic activity against cefotaxime than against ceftazidime and a pI of 9.0 and is encoded on a large self-transferable ca. 160-kbp plasmid.
Asunto(s)
Klebsiella pneumoniae/enzimología , beta-Lactamasas/genética , Sustitución de Aminoácidos , Cefotaxima/metabolismo , Cefalosporinas/metabolismo , Evolución Molecular , Humanos , Kenia , Klebsiella pneumoniae/genética , Datos de Secuencia Molecular , beta-Lactamasas/aislamiento & purificación , beta-Lactamasas/metabolismoRESUMEN
From a collection of cefotaxime-resistant Klebsiella pneumoniae isolated from neonatal blood culture specimens in a maternity hospital in Aracaju, Brazil, two isolates (strains KPBRZ-842 and -843, indistinguishable by pulsed-field gel electrophoresis) were found to produce beta-lactamases with isoelectric points (pI) of 5.4 and 8.2, respectively. Using a gel overlay method, cefotaxime hydrolysis was shown to be associated with the pI 8.2 protein. Nucleotide sequencing of the gene encoding the pI 8.2 beta-lactamase revealed a bla(SHV-ESBL)-type gene differing from the gene encoding SHV-1 by three silent point mutations, and a fourth that resulted in an amino acid substitution, aspartate for glycine, at position 156. This novel SHV-type extended-spectrum beta-lactamase is designated SHV-27.
Asunto(s)
Antibacterianos/metabolismo , Cefotaxima/metabolismo , Farmacorresistencia Microbiana/genética , Klebsiella pneumoniae/enzimología , beta-Lactamasas/metabolismo , Antibacterianos/farmacología , Aztreonam/farmacología , Brasil , Cefotaxima/farmacología , Ceftazidima/farmacología , Análisis Mutacional de ADN , Electroforesis en Gel de Campo Pulsado , Hospitales , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Mutación Puntual/genética , Polimorfismo de Longitud del Fragmento de Restricción , beta-Lactamasas/aislamiento & purificaciónRESUMEN
OBJECTIVES: To evaluate the reproducibility with which microbiologists interpret Gram-stained sputa and examine the effect of the smear preparation method. METHODS: Two hundred and ten coded slides prepared directly from a purulent portion of sputum (DS) and 140 slides prepared after homogenization of the same sputum (HS) were examined by three experienced microbiologists. A proportion of the slides prepared by each method were recorded and represented to the raters. Intraobserver and interobserver variation was assessed using the kappa statistic (kappa). RESULTS: Evaluation of the smear as being infected and predicting Streptococcus pneumoniae as the infecting organism showed the greatest intraobserver agreement (kappa=0.74-0.82) and interobserver agreement (kappa=0.50-0.82). The agreement concerning the number of cells and infection with Haemophilus influenzae was only fair to moderate. Differences in the interpretation of smears prepared by the two methods could be explained by the intrinsic disagreement that occurs when the same smear is examined twice. The positive predictive value of a positive S. pneumoniae smear for a positive culture ([10(6)/ml) was 81% with the DS and 97% with the HS. CONCLUSION: In this laboratory, a sputum Gram film interpretation suggesting infection with S. pneumoniae was reproducible and predictive of a significant positive culture.
Asunto(s)
Violeta de Genciana , Variaciones Dependientes del Observador , Fenazinas , Reproducibilidad de los Resultados , Infecciones del Sistema Respiratorio/diagnóstico , Esputo/microbiología , Coloración y Etiquetado/normas , Adolescente , Adulto , Infecciones por Haemophilus/diagnóstico , Haemophilus influenzae/química , Humanos , Valor Predictivo de las Pruebas , Estudios Prospectivos , Infecciones del Sistema Respiratorio/microbiología , Infecciones Estreptocócicas/diagnóstico , Streptococcus pneumoniae/químicaRESUMEN
The antimicrobial sensitivities of 78 recent (1995-1998) canine isolates of Bordetella bronchiseptica from 13 separate sources were determined. Minimum inhibitory concentrations were assessed using the E-test method or by agar dilution. All 78 isolates were sensitive to tetracycline, doxycycline, enrofloxacin, and amoxycillin/clavulanic acid; the majority were sensitive to ampicillin (63/78; 81%), trimethoprim (57/78; 73%), and sulphadiazine (63/78; 81%). Plasmids were detected in 14 out of the 24 isolates tested. There was no correlation between the presence of plasmids and antibiotic resistance, but there was some correlation between the presence of plasmids and the origin of the isolates. Three sizes of plasmid were found: 20, 14, and 5.5 kb. Eight of the isolates contained all three plasmids, the remainder one or two, Thirteen isolates demonstrated beta-haemolysis, of which six produced a soluble haemolysin. Except for one isolate, haemolysin production correlated with plasmid carriage. Pulsed-field gel electrophoresis showed that all except one isolate could be grouped in the same genotype. Within this genotype isolates could be divided into three subtypes, generally corresponding to their place of origin.
Asunto(s)
Infecciones por Bordetella/veterinaria , Bordetella bronchiseptica/efectos de los fármacos , Enfermedades de los Perros/microbiología , Fluoroquinolonas , Combinación Amoxicilina-Clavulanato de Potasio/farmacología , Combinación Amoxicilina-Clavulanato de Potasio/uso terapéutico , Ampicilina/farmacología , Ampicilina/uso terapéutico , Animales , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Antiinfecciosos/farmacología , Antiinfecciosos/uso terapéutico , Antiinfecciosos Urinarios/farmacología , Antiinfecciosos Urinarios/uso terapéutico , Infecciones por Bordetella/tratamiento farmacológico , Infecciones por Bordetella/microbiología , Bordetella bronchiseptica/química , Bordetella bronchiseptica/clasificación , ADN Bacteriano/química , Enfermedades de los Perros/tratamiento farmacológico , Perros , Doxiciclina/farmacología , Doxiciclina/uso terapéutico , Farmacorresistencia Microbiana/genética , Quimioterapia Combinada/farmacología , Quimioterapia Combinada/uso terapéutico , Electroforesis en Gel de Campo Pulsado/veterinaria , Enrofloxacina , Pruebas de Sensibilidad Microbiana/veterinaria , Penicilinas/farmacología , Penicilinas/uso terapéutico , Quinolonas/farmacología , Quinolonas/uso terapéutico , Factores R/aislamiento & purificación , Sulfadiazina/farmacología , Sulfadiazina/uso terapéutico , Tetraciclina/farmacología , Tetraciclina/uso terapéutico , Trimetoprim/farmacología , Trimetoprim/uso terapéuticoRESUMEN
Three episodes of Serratia marcescens pseudobacteraemia occurred on a neonatal intensive care unit. Following the first two cases, one full term and one pre-term infant, the source was identified as a glucose/lactate analyzer. Blood culture and environmental isolates of the organisms involved were indistinguishable when subjected to pulsed-field gel electrophoresis of Spe 1 digests and PCR ribotyping. Failure to recognize pseudobacteraemia in neonates results in inappropriate therapy for the individual and increased antibiotic pressures on the unit. Attention to the possibility of cross infection when using automated analyzers is required to minimize the risks of true or pseudoinfection to patients.
Asunto(s)
Bacteriemia/diagnóstico , Infección Hospitalaria/diagnóstico , Errores Diagnósticos , Contaminación de Equipos , Infecciones por Serratia/diagnóstico , Serratia marcescens/aislamiento & purificación , Glucemia/análisis , Electroforesis en Gel de Campo Pulsado , Femenino , Humanos , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/diagnóstico , Control de Infecciones/normas , Unidades de Cuidado Intensivo Neonatal , Ácido Láctico/análisis , Londres , Masculino , Reacción en Cadena de la Polimerasa , Serratia marcescens/genéticaRESUMEN
Whilst patient to patient spread of the respiratory pathogen Burkholderia cepacia is well recognised between patients with cystic fibrosis, prompting a strict segregation policy, cross colonisation between cystic fibrosis patients already infected with B cepacia has not been described and surveys show a very low incidence of patients with more than one strain. Five adult cystic fibrosis patients with B cepacia are presented who became cross colonised with a second B cepacia (UK epidemic) strain, four of whom then died, three from the cepacia syndrome. These cases show that, amongst segregated patients, cross colonisation with different B cepacia strains is possible, and even in these patients the acquisition of the UK epidemic strain may have a fatal outcome. In future it may be necessary to segregate cystic fibrosis patients colonised with the UK epidemic strain from all other patients with cystic fibrosis.
Asunto(s)
Infecciones por Burkholderia/transmisión , Burkholderia cepacia , Infección Hospitalaria/microbiología , Fibrosis Quística/microbiología , Adolescente , Adulto , Burkholderia cepacia/genética , ADN Bacteriano/análisis , Electroforesis en Gel de Campo Pulsado , Resultado Fatal , Genotipo , Humanos , Masculino , Reacción en Cadena de la PolimerasaRESUMEN
The flagellin gene sequence from a clinical isolate of Burkholderia pseudomallei was used to design oligonucleotide primers for PCR/RFLP analysis of flagellin gene variation among clinical and environmental isolates of B. pseudomallei. Genes from four clinical and six environmental isolates were amplified and compared by RFLP. The clinical isolates were indistinguishable, but variation was detected among some of the environmental isolates. Sequence analysis of flagellin gene amplified products demonstrated high levels of conservation amongst the flagellin genes of clinical isolates (>99% similarity), compared to the variation observed between the clinical isolates and one of the environmental isolates (<90% similarity). Genomic comparisons with pulsed-field gel electrophoresis (PFGE) revealed differences between the relationships inferred by flagellin genotyping and PFGE, suggesting that a combination of molecular methods may be useful for the subtyping of B. pseudomallei strains.
Asunto(s)
Burkholderia pseudomallei/genética , Microbiología Ambiental , Flagelina/genética , Variación Genética , Melioidosis/microbiología , Proteínas de la Membrana Bacteriana Externa/genética , Secuencia de Bases , Clonación Molecular , ADN Bacteriano/química , Electroforesis en Gel de Campo Pulsado , Proteínas Fimbrias , Genotipo , Humanos , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Alineación de SecuenciaRESUMEN
Of 52 antibiotic-resistant Bordetella bronchiseptica isolates from cats, ten carried plasmids. Only two of these plasmids, pLV1400 and pLV1401, were self-transmissible to Escherichia coli K12; both plasmids encoded resistance to ampicillin, tetracycline, sulphonamides, streptomycin and mercuric chloride, and were of incompatibility group P (IncP). Transferable tetracycline resistance has not been reported in B. bronchiseptica previously. The plasmids were identical in size (c.51 kb), restriction endonuclease digestion pattern and gene sequences (trfA and korA) within the IncP replicon. The trfA and korA sequences differed from those of the archetypal IncP plasmids RP4 and R751. Although the two B. bronchiseptica isolates were from epidemiologically and geographically separated cats, pulsed-field gel electrophoresis of their XbaI- or DraI-digested chromosomal DNA indicated that they were genotypically identical. The plasmid-encoded ampicillin resistance was mediated by a penicillinase of molecular weight 49,000, and pI 8.45 which was inhibited by clavulanate (IC50 = 0.1 mg/L) and tazobactam (IC50 = 0.42 mg/L) but not by parachloromercuribenzoate or EDTA. The high-level tetracycline resistance was mediated by a class C efflux mechanism that has not been described previously in this genus. The presence of transferable multi-drug resistance on a promiscuous plasmid may limit options for therapy of respiratory tract infection in companion and farm animals.