ABSTRACT
BACKGROUND: Acute kidney injury (AKI) requiring dialysis in critically ill patients is associated with an in-hospital mortality rate of 50-80 %. Extended daily hemodialysis (EHD) and high volume peritoneal dialysis (HVPD) have emerged as alternative modalities. METHODS: A double-center, randomized, controlled trial was conducted comparing EHD versus HVPD for the treatment for AKI in the intensive care unit (ICU). Four hundred and seven patients were randomized and 143 patients were analyzed. Principal outcome measure was hospital mortality, and secondary end points were recovery of renal function and metabolic and fluid control. RESULTS: There was no difference between the two groups in relation to median ICU stay [11 (5.7-20) vs. 9 (5.7-19)], recovery of kidney function (26.9 vs. 29.6 %, p = 0.11), need for chronic dialysis (9.7 vs. 6.5 %, p = 0.23), and hospital mortality (63.4 vs. 63.9 %, p = 0.94). The groups were different in metabolic and fluid control. Blood urea nitrogen (BUN), creatinine, and bicarbonate levels were stabilized faster in EHD group than in HVPD group. Delivered Kt/V and ultrafiltration were higher in EHD group. Despite randomization, there were significant differences between the groups in some covariates, including age, pre-dialysis BUN, and creatinine levels, biased in favor of the EHD. Using logistic regression to adjust for the imbalances in group assignment, the odds of death associated with HVPD was 1.4 (95 % CI 0.7-2.4, p = 0.19). A detailed investigation of the randomization process failed to explain the marked differences in patient assignment. CONCLUSIONS: Despite faster metabolic control and higher dialysis dose and ultrafiltration with EHD, this study provides no evidence of a survival benefit of EHD compared with HVPD. The limitations of this study were that the results were not presented according to the intention to treat and it did not control other supportive management strategies as nutrition support and timing of dialysis initiation that might influence outcomes in AKI.
Subject(s)
Acute Kidney Injury/therapy , Peritoneal Dialysis/methods , Renal Dialysis/methods , Acute Kidney Injury/metabolism , Acute Kidney Injury/mortality , Aged , Blood Urea Nitrogen , Brazil/epidemiology , Creatinine/metabolism , Female , Follow-Up Studies , Hospital Mortality/trends , Humans , Intensive Care Units , Male , Middle Aged , Retrospective Studies , Treatment OutcomeABSTRACT
1. Outer-membrane protein patterns of Escherichia coli recovered from the peritoneal cavities of infected guinea pigs and grown in medium M9 containing 2,2'-dipyridyl were studied by polyacrylamide gel electrophoresis (SDS-PAGE) to determine whether in vivo conditions of growth affected the expression of these bacterial surface proteins. 2. Eleven strains of septicemic E. coli studied in vitro under conditions of iron restriction expressed iron-regulated outer-membrane proteins, mainly the protein of approximately 74 kDa, whereas avirulent strains grown under similar conditions did not present the 74-kDa protein. 3. These results show the distribution of iron-regulated outer-membrane proteins among avian E. coli and suggest that the protein of approximately 74 kDa may be important for the virulence of these strains.
Subject(s)
Bacterial Outer Membrane Proteins/physiology , Escherichia coli/physiology , Iron/physiology , 2,2'-Dipyridyl , Animals , Chickens , Electrophoresis, Polyacrylamide Gel , Escherichia coli/growth & development , Escherichia coli/pathogenicity , Guinea PigsABSTRACT
1. Outer-membrane protein patterns of Escherichia coli recovered from the peritoneal cavities of infected guinea pigs and grown in medium M9 containing 2,2'-dipyridyl were studied by polyacrylamide gel electrophoresis (SDS-PAGE) to determine whether in vivo conditions of growth affected the expression of these bacterial surface proteins. 2. Eleven strains of septicemic E. coli studied in vitro under conditions of iron restriction expressed iron-regulated outer-membrane proteins, mainly the protein of approximately 74 kDa, whereas avirulent strains grown under similar conditions did not present the 74-kDa protein. 3. These results show the distribution of iron-regulated outer-membrane proteins among avian E. coli and suggest that the protein of approximately 74 kDa may be important for the virulence of these strains.
Subject(s)
Animals , Guinea Pigs , Escherichia coli , Iron , Bacterial Outer Membrane Proteins/physiology , 2,2'-Dipyridyl , Chickens , Electrophoresis, Polyacrylamide Gel , Escherichia coliABSTRACT
1. We cloned the aerobactin region and its receptor from pMV14, a large nonconjugative plasmid isolated from the virulent strain UEL14, to assess the importance of the aerobactin iron uptake system as a virulence determinant in septicemic avian Escherichia coli. 2. The physical map of the region of the recombinant plasmid (pGMV1) containing the genes for synthesis of aerobactin and its receptor was very similar to the corresponding region in pABN1 containing the genetic determinants for the aerobactin system of pColV-K30. 3. The 74-kDa outer-membrane protein encoded by pGMV1 cross-reacted immunologically with the 74-kDa aerobactin receptor protein encoded by pABN1. 4. Various avirulent E. coli strains carrying the recombinant plasmid, which contains only the aerobactin system, were assayed for virulence and were found to be avirulent for chickens. Only the wild-type aerobactin-producing strain was virulent in a pathogenicity test for chickens. 5. These results show that the aerobactin system by itself does not confer virulence, and that other factors are necessary for virulence of avian strains of E. coli.
Subject(s)
Escherichia coli/pathogenicity , Hydroxamic Acids/metabolism , Transformation, Bacterial , Animals , Bacterial Outer Membrane Proteins/analysis , Blotting, Southern , Chickens , Cloning, Molecular , DNA Probes , Electrophoresis, Polyacrylamide Gel , Escherichia coli/genetics , Escherichia coli/metabolism , Plasmids/isolation & purification , VirulenceABSTRACT
1. We cloned the aerobactin region and its receptor from pMV14, a large nonconjugative plasmid isolated from the virulent strain UEL14, to assess the importance of the aerobactin iron uptake system as a virulence determinant in septicemic avian Escherichia coli. 2. The physical map of the region of the recombinant plasmid (pGMV1) containing the genes for synthesis of aerobactin and its receptor was very similar to the corresponding region in pABN1 containing the genetic determinants for the aerobactin system of pColV-K30. 3. The 74-kDa outer-membrane protein encoded by pGMV1 cross-reacted immunologically with the 74-kDa aerobactin receptor protein encoded by pABN1. 4. Various avirulent E. coli strains carrying the recombinant plasmid, which contains only the aerobactin system, were assayed for virulence and were found to be avirulent for chickens. Only the wild-type aerobactin-producing strain was virulent in a pathogenicity test for chickens. 5. These results show that the aerobactin system by itself does not confer virulence, and that other factors are necessary for virulence of avian strains of E. coli
Subject(s)
Animals , Hydroxamic Acids/metabolism , Escherichia coli/pathogenicity , Transformation, Bacterial , Blotting, Southern , Chickens , Cloning, Molecular , DNA Probes , Electrophoresis, Polyacrylamide Gel , Escherichia coli/genetics , Escherichia coli/metabolism , Plasmids/isolation & purification , Bacterial Outer Membrane Proteins/analysis , VirulenceABSTRACT
1. Strains of avian septicemic E. coli were examined for association among the determinants of drug resistance, the genes for aerobactin production and virulence. 2. In conjugation experiments, a single plasmid (100 Md) from a strain of septicemic E. coli (UEL 29) transferred to E. coli K12 pathogenicity for 1-day old chicks plus resistance to streptomycin and the ability to produce aerobactin and colicin. 3. Additional evidence for the association of R-plasmid and the production of aerobactin, colicin, resistance to sulfadiazine and pathogenicity was obtained by disassociation when all traits were lost simultaneously. 4. These data provide additional evidence for the importance of the aerobactin system for the pathogenicity of avian E. coli.
Subject(s)
Chickens , Escherichia coli/pathogenicity , Hydroxamic Acids/metabolism , Plasmids/genetics , Animals , Colicins/biosynthesis , Drug Resistance, Microbial/genetics , Escherichia coli/genetics , Genes, Bacterial , R Factors , Streptomycin , Sulfadiazine , Virulence/geneticsABSTRACT
Strain of avian septicemic E. coli were examined for association among the determinants of drug resistance, the genes for aerobactin production and virulence. In conjugation experiments, a single plasmid (100 Md) from a strain of septicemic E. coli (UEL 29) transferred to E. coli K12 pathogenicity for 1-day old chicks plus resistance to streptomycin and the ability to produce aerobactin and colicin. Additional evidence for the association of R-plasmid and the production of aerobactin, colicin, resistance to sulfadiazine and pathogenicity was obtained by disassociation when all traits were lost simultaneously. These data provide additional evidence for the importance of the aerobactin system for the pathogenicity of avian E. coli