Infecciones por Escherichia coli productora de toxina Shiga O121: H19 en pacientes atendidos en Mar del Plata / Infections caused by Escherichia coli producing Shiga O121: H19 toxin in patients treated in Mar del Plata

Escherichia coli productora de toxina Shiga (STEC) O157:H7 es el serotipo más frecuentemente identificado como agente causal de colitis hemorrágica y síndrome urémico hemolítico (SUH), aunque se han descripto más de 100 serotipos con potencial patogénico similar. El objetivo del trabajo fue describir casos de enfermedad humana asociados a la infección por STEC O121:H19, atendidos en la ciudad de Mar del Plata y establecer la relación genética de los aislamientos mediante técnicas de epidemiología molecular. Se observó un amplio espectro en la severidad clínica de los ocho casos estudiados: dos fueron asintomáticos (contactos de SUH), un paciente tuvo diarrea sanguinolenta, y cinco presentaron SUH. Uno de los pacientes con SUH falleció. Las cepas O121:H19 portadoras del genotipo stx2a/eae/ehxA fueron sensibles a los antibióticos ensayados y presentaron por electroforesis en gel de campo pulsado (Xbal-PFGE) distintos patrones de macrorrestricción, con similitud del 84,25%. El patrón AREXKX01.0072, detectado en un SUH y en su contacto, es nuevo en la Base de Datos Nacional de STEC no-O157 de la Argentina. La utilización de métodos estandarizados de detección y tipificación de STEC permite a los laboratorios de referencia monitorear la frecuencia temporal y la distribución geográfica de las cepas circulantes para la prevención y control de estos patógenos asociados a enfermedad humana.

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is the most frequent serotype identified as causative agent of sporadic cases and outbreaks of diarrhea with or without blood, hemorrhagic colitis and hemolytic uremic syndrome (HUS), although more than 100 serotypes have been described of similar pathogenic potential. The aim of the study was to describe cases of human disease associated with STEC O121:H19 infections, assisted in Mar del Plata City, and to establish the genetic relationship of the isolates by molecular epidemiology techniques. A wide spectrum was observed in the clinical severity of the eight cases studied: two were asymptomatic (contacts of HUS), one patient had bloody diarrhea, and five cases presented HUS. One HUS case died. All STEC O121:H19 strains carried the stx2a/eae/ehxA genotype, were sensitive to all antibiotics tested and showed different macrorestriction patterns by pulsed-field gel electrophoresis (Xbal-PFGE), with 84.25% similarity. The pattern AREXKX01.0072, detected in a HUS case and in his contact, is new in the Argentine National Database of non-O157 STEC. The use of standardized methods for detection and typing of STEC allows reference laboratories to monitor the temporal frequency and geographical distribution of circulating strains for the prevention and control of these pathogens associated with human diseases.

Escherichia coli produtora de toxina Shiga (STEC) O157:H7 é o sorotipo mais frequentemente identificado como o agente causador de colite hemorrágica e síndrome hemolítica urêmica (SHU), embora tenham sido descritas mais de 100 sorotipos com potencial patogênico semelhantes. O objectivo foi o de descrever os casos de doença humana associadas com a infecção por STEC O121:H19, assistido, na cidade de Mar del Plata e estabelecer relação genética de isolados utilizando epidemiologia molecular. Um amplo espectro foi observado na severidade clínica dos oito casos estudados, dois eram assintomáticos (contacto SHU), uma paciente teve diarreia com sangue, e cinco tiveram SHU. Um caso de SHU faleceu. As cepas O121:H19 portaram o genótipo stx2a/eae/ehxA, foram sensíveis aos antibióticos testados e apresentaram, por eletroforese em gel de campo pulsado (Xbal-PFGE), diferentes padrões de macrorestrição, com similaridade de 84,25%. O padrão AREXKX01.0072 detectado em SHU e em seu contato, é novo para a Base de Dados Nacional de STEC não-O157 na Argentina. O uso de métodos padrão de detecção e tipagem de STEC permite os laboratórios de referência monitorar frequência temporal e distribuição geográfica de estirpes circulantes para a prevenção e controlo destes agentes patogénicos associados com a doença humana.

Factor H and CFHR1 polymorphisms associated with atypical Haemolytic Uraemic Syndrome (aHUS) are differently expressed in Tunisian and in Caucasian populations.

Several polymorphisms in the complement components factor H and CFHR1 are associated with higher risk to develop atypical Haemolytic Uraemic Syndrome (aHUS) in Caucasians. We have determined the prevalence of these polymorphisms in Tunisian controls by using genetic and immunological techniques. No differences in the frequency of the factor H risk alleles c.-331C>T, c.2089A>G or c.2881G>T between Tunisian and Caucasians were found. On the contrary, the analysis of CFHR1 polymorphism revealed a higher frequency of Tunisian individuals homozygous for the CFHR1*Del (deleted) allele, and of individuals presenting the CFHR1*A phenotype. These results suggest distinct contributions of factor H and CFHR1 polymorphisms to aHUS in Tunisian and Caucasian populations.

Ten years of pneumococcal-associated haemolytic uraemic syndrome in New Zealand children.

AIM: To describe the epidemiology, clinical features, management and outcome of pneumococcal-associated haemolytic-uraemic syndrome (P-HUS) in New Zealand over the past decade. METHODS: A retrospective chart review of children with P-HUS from 1998 to 2007 that were prospectively reported to the New Zealand Paediatric Surveillance Unit. P-HUS was defined as microangiopathic haemolytic anaemia (Hb <100 g/L with fragmented red blood cells), thrombocytopaenia (platelet count <130 x 10(9)/L), acute renal impairment with oliguria and elevated plasma creatinine, and confirmed or suspected pneumococcal infection. RESULTS: Eleven children (nine male, two female), predominately Maori and Polynesian (10 children) were studied. The median age was 8.5 months. The median duration of hospitalisation was 25 days. Of the infections, 10 were confirmed pneumococcal (six pneumonia, four meningitis) and one pneumonia was suspected pneumococcal (culture negative, however T activation positive). Nine patients required dialysis for a median duration of 13 days. One child with meningitis died after therapy was withdrawn because of severe neurological injury. One patient developed end stage kidney disease and two further children had evidence of persisting renal sequelae at follow-up. CONCLUSIONS: Pneumococcal disease remains an important public health problem in New Zealand children, particularly those of Maori and Pacific Island ethnicity. P-HUS should be considered in pneumococcal disease associated with severe haematological and renal abnormalities. These children should be monitored long-term, as they are at risk of permanent renal injury.

Non-enteropathic hemolytic uremic syndrome: causes and short-term course.

BACKGROUND: Nondiarrheal or Streptococcus pneumoniae-related hemolytic uremic syndrome (HUS) represents a heterogeneous group of disorders. This study was performed to: (1) describe the current incidence, causes, demographic features, hospital courses, and short-term outcomes of non-enteropathic HUS; (2) compare findings in patients with non-enteropathic HUS with those obtained from a contemporaneous cohort of children with enteropathic or diarrhea-associated HUS (D+ HUS) diagnosed and treated at the same clinical sites; and (3) identify clinical or laboratory features that differentiate these 2 groups and predict disease severity and the short-term outcome in patients with non-enteropathic HUS. METHODS: Data were collected from patients screened between 1997 and 2001 for enrollment in a multicenter trial of SYNSORB Pk (SYNSORB Biotech Inc, Calgary, Alberta, Canada) in D+ HUS, but who were ineligible because of lack of a diarrhea prodrome. The following features were recorded: age; sex; ethnicity; prodromal symptoms; cause; nadir values for hemoglobin, hematocrit, and platelet count; use of dialysis; and length of hospitalization. RESULTS: Twenty-seven of 247 children with HUS had non-enteropathic HUS (11%). Twenty-four patients (15 boys, 9 girls), whose medical records were complete and available for review, comprise the study cohort. Mean age at onset was 4.2 +/- 0.9 (SE) years. Infection caused by S pneumoniae was diagnosed in 9 patients (38%). Dialysis was performed in 17 patients (71%) for 40 +/- 27 days. Median length of hospitalization was 22 days (range, 2 to 71 days). Children with S pneumoniae-related HUS had a longer hospital stay than those with other causes of non-enteropathic HUS, but all patients with S pneumoniae-related HUS recovered kidney function. Dialysis therapy was required more often (17 of 24 versus 59 of 145 children; P = 0.025) and hospital stays were longer (median, 22 versus 9 days; P = 0.002) in children with non-enteropathic HUS compared with patients with D+ HUS who were enrolled in the SYNSORB Pk clinical trial. CONCLUSION: (1) The incidence of non-enteropathic HUS is approximately one tenth that of D+ HUS; (2) patients with non-enteropathic HUS require dialysis therapy more often and are hospitalized more than twice as long during the acute episode compared with those with D+ HUS; (3) infection caused by S pneumoniae accounts for nearly 40% of cases of non-enteropathic HUS; and (4) although S pneumoniae-related HUS is associated with a less favorable short-term course than other types of non-enteropathic HUS or D+ HUS, the long-term prognosis for recovery of renal function appears to be good in these patients.

Hemolytic uremic syndrome in Kuwaiti Arab children.

Twenty-five children with hemolytic uremic syndrome (HUS) were diagnosed between January 1985 and January 2000 in the Pediatric Nephrology Unit at Mubarak Al-Kabeer Hospital. Fourteen patients (56%) had typical (D+) HUS whereas 11 (44%) had atypical (D-) HUS. No bacterial or viral pathogens could be isolated in the majority of cases. The atypical HUS group had more severe anemia (P=0.03), which was significantly more prolonged than in the typical HUS group (P=0.0028). There was no significant difference between the two groups in the mean maximum serum creatinine (P=0.1), blood urea nitrogen values (P=0.8) and severity of leukocytosis (P=0.4). Anuria and the need for dialysis were not significantly different between the two groups (P=0.1 and 0.05, respectively). Mortality was significantly higher in the D- HUS patients (P<0.0001). Recurrence of HUS was documented in 63.3% of the D- HUS group compared to 14.2% of the D+ HUS group (P=0.0053). Family history of HUS was reported in 72.7% of the atypical HUS group and 14.2% of the typical HUS group. There were no significant differences in chronic renal sequelae between the two groups. In conclusion, the pathogenesis of HUS in Kuwaiti children appears to be influenced by genetic factors rather than certain environmental pathogens. Atypical HUS has a higher mortality rate, a definite familial tendency and a high relapse rate.

Racial incidence of hemolytic uremic syndrome.

Hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure in children and is caused by infection with verotoxin-producing Escherichia coli. There is no consensus on the relative incidence of HUS in blacks and whites. An equal racial incidence has been reported by two centers with small black populations. A series from Washington D.C. reported a low incidence in blacks. The population of Alabama is 32% black and 66% white. The Children's Hospital of Alabama admission rate has a similar racial distribution (35% black, 65% white). A record review from 1980-1992 identified 45 patients with HUS; 43 (96%) were white and only 2 (4%) were black. Based on census data for Alabama in 1980 and 1990, this gives an average annual incidence of HUS of 0.45 per 100,000 in whites and of 0.043 per 100,000 in blacks (P < 0.001, Fischer's exact test). Similar results were found in the group of patients with HUS and a history of diarrhea; whites 0.39 and blacks 0.02 (P < 0.001). However, in those with no history of diarrhea there was no significant racial difference: whites 0.05 and blacks 0.02. There were too few blacks to compare clinical course and outcome. We conclude that typical diarrhea-associated HUS is a relatively rare disease in blacks compared with whites. The reasons are unclear.