RESUMO
The development of renal scarring was analyzed prospectively in 241 boys with their first known episode of symptomatic urinary tract infection (140 acute pyelonephritis, 61 acute cystitis, and 40 nonspecific). Of 197 boys undergoing urography, 22 (11%) had scars; 20 were in the pyelonephritis group. Vesicoureteral reflux occurred in 81% of those with scarring, compared with 20% of those without scarring. The bacteria causing the first episode of urinary tract infection in each patient were saved, and Escherichia coli organisms were characterized for the expression of both galactose-alpha (1----4)galactose-beta (Gal-Gal)-specific adhesins and pap homologous DNA. Scarring occurred in 41% and other renal abnormalities in 11% of boys infected with bacteria that did not bind Gal-Gal (Gal-Gal negative), compared with 5% and 1%, respectively, in those infected with Gal-Gal-binding strains (Gal-Gal-positive) (relative risk 8.3; 95% confidence limits 3.3 to 20.4; p less than 0.001). That boys infected with Gal-Gal-negative strains more often had reflux did not explain the increased risk for renal scarring in this group. The possibility that the phenotypically negative strains could be induced to express Gal-Gal adhesions in vivo was excluded by dot blot analysis, which showed the absence of pap homologous DNA in all but one of the Gal-Gal-negative strains. The results suggest that the absence of Gal-Gal-specific adhesins in E. coli can be used as an indicator of risk for renal scarring and the need for radiologic examination.
Assuntos
Aderência Bacteriana , Cicatriz/etiologia , Cistite/microbiologia , Escherichia coli/patogenicidade , Pielonefrite/microbiologia , Infecções Urinárias/microbiologia , Adolescente , Criança , Pré-Escolar , Cistite/complicações , Cistite/tratamento farmacológico , Galactose/metabolismo , Humanos , Lactente , Recém-Nascido , Nefropatias/etiologia , Masculino , Estudos Prospectivos , Pielonefrite/complicações , Pielonefrite/tratamento farmacológico , Fatores de Risco , Infecções Urinárias/complicações , Infecções Urinárias/tratamento farmacológico , UrografiaRESUMO
The relationship between acute-phase responses and bacterial properties was studied in a population of 88 children with their first known episode of acute pyelonephritis. One strain from each patient was included in the study. Eighty-four of the patients were infected with Escherichia coli, which was assigned a clonotype according to the O:K:H stereotype; 55 patients carried one of the 12 multiply occurring clones. Globotetraosylceramide-specific (globo+) adhesion was present in 90% of these 12 clones, compared with 62% in the remaining 29 singly occurring clones. The patients infected with globo+ strains had significantly increased inflammatory reactions compared with patients with globo- strains. The O1:K1:H7 strain was the single most frequent clone (n = 14) that always expressed globo+ adhesins. Patients infected with O1:K1:H7 had an inflammatory response similar to that of other globo+ infections, but had a shorter duration of symptoms before diagnosis, higher fever, and higher peripheral leukocyte count. These results demonstrate special virulence of the O1:K1:H7 clone, reflected by the acuteness of onset of infection.
Assuntos
Escherichia coli/genética , Pielonefrite/microbiologia , Criança , Pré-Escolar , Células Clonais/análise , Escherichia coli/patogenicidade , Feminino , Humanos , Lactente , Masculino , Estudos ProspectivosRESUMO
Two populations were analyzed prospectively after a first episode of urinary tract infection. Asymptomatic infants were screened at 2 weeks and at 3 and 10 months of age, and bacteriuria was confirmed by bladder puncture. Infants with febrile urinary tract infection were enrolled during the same study period. The inflammatory response was characterized by the presence of fever, serum C-reactive protein, microsedimentation rate, urinary leukocyte excretion, and width of the ureters. The bacteria were defined for O:K:H serotype, hemolysin production, resistance to the bactericidal effect of serum, attachment to uroepithelial cells, and specificity for the globoseries of glycolipid receptors. In agreement with previous studies, the frequency of increased inflammatory signs and of attaching Escherichia coli was significantly higher in infants with febrile urinary tract infection than in the screening group. Within both patient groups, however, children infected with attaching E. coli strains had significantly more inflammatory signs. The results suggest that adherence facilitates the presentation of bacterial components capable of causing inflammation in the tissues in the urinary tract.
Assuntos
Infecções Urinárias/fisiopatologia , Sedimentação Sanguínea , Proteína C-Reativa/análise , Escherichia coli/isolamento & purificação , Feminino , Febre/microbiologia , Febre/fisiopatologia , Humanos , Lactente , Recém-Nascido , Inflamação/fisiopatologia , Masculino , Estudos Prospectivos , Infecções Urinárias/microbiologiaRESUMO
The immune response of the mammary gland is dominated by local production of secretory IgA antibodies (SIgA). These milk antibodies, amounting to about 0.5-1 g/day throughout lactation, are directed against food proteins and microorganisms often present in the intestine. This is presumably explained by the enteromammaric link: after antigenic exposure in the Peyer's patches of lymphoid cells they home to various exocrine glands, including the mammary gland. Similarly, lymphoid cells from the bronchial mucosa, may contribute to the antibody-producing cell population in the mammary gland. SIgA antibodies against common foods like cow's milk and soy proteins are regularly found in milk if such proteins are part of the mother's diet. It is possible, but unproven, that milk antibodies can decrease the exposure of the infant's intestinal mucosa to foreign food proteins introduced during continued breast-feeding. Milk SIgA antibodies do not prevent intestinal colonization by microorganisms, against which the milk antibodies are directed. The SIgA antibodies are thought to exert protection primarily by preventing contact between the microorganisms and the mucosal membranes. In this manner, human milk blocks attachment of otitis media-causing strains of pneumococci and H. influenzae to retropharyngeal cells, possibly explaining why breast-feeding may prevent otitis media. Milk antibodies have anti-attachment capacity, but there is also low molecular weight material in the milk with this capacity. It probably consists of analogues to the oligosaccharide receptor for pneumococci on the retropharyngeal cells.(ABSTRACT TRUNCATED AT 250 WORDS)