Diarrhoeal disease

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Hypothesis: A clinical pathway utilising rapid rehydration of children who are moderately dehydrated from acute gastroenteritis will decrease the admission rate and length of stay in the Emergency Department (ED). Methods: The study took place in the ED of The Children’s Hospital, Westmead. This was a prospective before-and- after intervention study, with the intervention being the above mentioned clinical pathway. The intervention group was recruited from March to December 1999. Aged and gender matched historical controls were recruited from the same period in 1997. The study population for both groups was all children between 6 months and 16 years presenting to the ED with gastroenteritis, who had vomiting and diarrhoea for < 48 hours and were not severely dehydrated. The pathway involved an assessment of dehydration and a trial of oral fluids. If this failed, rapid rehydration was commenced either intravenously using N/2 Saline + 2.5% Dextrose over 2 hours at 20ml/kg/hr, or via nasogastric tube with Gastrolyte at the same rate. They were given another trial of fluids and discharged if successful. Outcome measures were the percentage of patients discharged from the ED in < 8 hours and the rate of admission. Results: In both groups 145 patients were recruited. In the moderately dehydrated patients, 45% of the intervention group were discharged in < 8 hours, compared with 4% in the before intervention group (p<.001). The admission rate in the intervention group was 56% compared with 96% in the before group (p<.001). In the mildly dehydrated patients, 61% of the intervention group were discharged in < 8 hours compared with 76% of the before group (p<.05). The admission rates of 24% and 27% were not statistically different. Conclusion: A clinical pathway utilising rapid rehydration of children who are moderately dehydrated from acute gastroenteritis is effective in significantly reducing admission rates and length of stay in the ED. This approach is not appropriate for children who are mildly dehydrated.

HUS, a complication of gastrointestinal infection with Shiga toxin-producing E.coli (STEC) is characterised by microangiopathic haemolytic anaemia, thrombocytopaenia and acute renal failure. In Europe, North America and Japan, STEC O157:H7 is commonly implicated. Shigella dysenteriae is frequently implicated in developing communities. Aim: To determine the aetiology of HUS in Australia and the type and virulence characteristics of stool pathogens. Methods Active, national surveillance for HUS with monthly reporting by paediatricians. Stool culture, serotyping and virulence characteristics (production of Shiga toxin [Stx] 1 & 2 and enterohaemolysin, and carriage of eae gene) of isolates in specialised laboratories. Results Between July 1994-December 2000, 134 children with HUS were identified (114 with 'diarrhoea-associated' HUS (20 comprised an outbreak) and 20 with 'atypical' HUS. Of 114 cases with gastrointestinal symptoms, 59 were male, mean(SD) age 50(43) months, range 2-169 months (71% <5 years). All had anaemia and acute renal failure. Symptoms included diarrhoea (96%), bloody diarrhoea (47%), and vomiting 78%. Stool +/or sera were received from 74 (65%) STEC serotypes from 44 cases included O111:H- (26), O113:H21 (5), O157:H- (2), O157:H? (2), and one each of O26:H-, O111:H8, O76:H7, O15:H-, O130:H11, O1:H7, OR:H9, ONT:H7, ONT:H-. The most common isolate was O111:H-, which also caused the outbreak. All O111:H- produced Stx1, Stx2 and enterohaemolysin and carried eae. Other isolates had ³ 1 but not all these virulence characteristics. Conclusion: A heterogeneous group of STEC was associated with HUS in Australia and differs from that described elsewhere. In particular, no O157:H7 was isolated. These findings have implications for laboratory diagnosis and epidemiological tracing of STEC-associated infections.

P6 - Cryptosporidium Infection in Children in Urban Bangladesh

We reviewed data during 1991-1994 from a systemic 4% subsample of all patients who presented with diarrhoea to our facility, in which there were 1,949 cases of acute diarrhoea in children between the ages of birth to 59 months. Cryptosporidia oocytes were detected in the stools of 68 children with stool positive for cryptosporidium as cases. Two hundred four children who did not have cryptosporidium were randomly selected to serve as controls. The most common presentations were watery diarrhoea (91%), dehydration (81%) and vomiting (71%), and cryptosporidium was detected throughout the year, but was most frequently isolated during April and October. Lowest rates of detection were observed in the months of November, December and January. Age beyond six months, non-breastfeeding, and stunting were significantly associated with cryptosporidium infection. In multivariate analysis of our study we found that only stunted (p=0.031) and non-breastfed children (p=0.022) had greater risk of having Cryptosporidium infection.

Rotavirus infection is associated with 150,000 –200,000 deaths annually in Africa. Although the withdrawal of the RotaShieldÒ vaccine has been a major setback in rotavirus vaccine development, new vaccine candidates are under development and approaching phase II and III trials. Before these trials could be conducted in Africa, a comprehensive survey of the circulating VP7 serotypes and VP4 genotypes is required. During the past three years, over 3,000 rotavirus positive specimens from several countries have been analysed. RT-PCR techniques for the VP7 and VP4 genotypes and by monoclonal antibodies to the VP6 subgroup and VP7 serotype have been performed. Almost 75% of the strains were typed by the VP7 monoclonal antibodies or RT-PCR. VP4 genotyping was done in approximately half of these strains. The predominant strains circulating across Africa during 1996-1999 were P[6]G1 and P[6]G3 strains. Geographic differences were noted and West Africa displayed the most diverse strains with G3/8 and G1/3 mosaic viruses occurring commonly. G9 strains were identified in several countries indicating that the strain is emerging in Africa too. It was the predominant strain in certain countries during 1999. The circulating types observed will have implications for the new rotavirus vaccine candidates.

– 18 Year Surveillance of Rotavirus Infection in South Africa

Rotavirus infection is associated with acute infantile gastro-enteritis in infants and young children globally. In South Africa, rotavirus infection has been shown to be associated with approximately 25% of all diarrhoeal admissions to hospital. Rotavirus infection predominantly occurs in infants less than 12 months of age (83%) and has a peak in shedding during the cooler, drier months of the year. A secondary peak during the spring has been observed. Clinically rotavirus infection has been statistically associated with increased fever and vomiting and dehydration in these children. The circulating VP7 serotypes and VP4 genotypes have been determined in various regions of South Africa and show a geographic specific distribution. Although in the past, P[8]G1or G4 strains predominated, P[4]G2 strains occurred in peaks every 3-4 years, and sometimes contributed to unusually significant rotavirus seasons. More recently, rotavirus strains with P[6] genotype have become common and novel VP7 serotypes are occurring across the country. G9 strains have been reported from Cape Town to Vendaland. The circulating rotavirus types observed in this study add to the knowledge of the natural history of rotavirus infection and should be considered when considering future vaccine strategies.

Toxigenic Escherichia coli strains that cause diarrhoea disease in human and domestic animals have been classified three categories: enterotoxigenic E.coli (ETEC) Shiga-like toxin E.coli (SLTEC), and necrotoxigenic E.coli (NTEC). The SLTEC strains may produce three main types of Shiga-like-toxin (SLT1, SLT2, SLT2v) that are similar to Shiga toxin synthesised by Shigella dysenteriae type I (such as O157:H7). SLTEC (SLT1, and/or SLT2) strains are recognised as a cause of haemorrhagic colitis and the haemolytic-uraemic syndrome in humans, furthermore, SLTEC strains producing SLT2v are responsible for the oedema disease in pigs. In the recent discovery a new category of the entero-SLTs-producing Escherichia coli (ESIEC) isolated from patients with diarrhoea disease in China. In the study, to evaluation of aetiology for Shiga-like toxin-producing Escherichia coli (SLTEC) in children with diarrhoea disease. We designed and synthesised 3 pairs of primers located in SLT1, SLT2, and eaeA genes of EHEC. While the virulence genes in SLT1, SLT2, and eaeA in 29 reference strains of diarrhoea causing E.coli (DCEC) and 10 strains of other enterobacteria detected by PCR had positive reaction, while all other DCEC and enterobacteria were negative. A total of 474 strains of E.coli isolated from children with diarrhoea disease detected by PCR were 20 strains of SLT1 producing E.coli (4.2%) positive, and 7 strains of SLT2 producing E.coli (1.5%) positive, while 74 strains of ESIEC were 15 strains of SLT1 (20.3%) and 5 strains of SLT2 (6.8%) positive. Conclusion Shiga-like toxin E.coli has been identified as a major aetiologic agent of children with diarrhoea disease in Taiyuan.

Introduction This study presented the prevalence and antibiotic susceptibility of children with acute diarrhoea. Method: We collected stool specimens cultured from children hospitalised due to acute diarrhoea at our hospital during four year period (1996-1999). The sample were cultured as appropriate, and determining the sensitivity for antibiotic was assessed. Results: During the study period, 5305 out of 7199 cultures were positive. A bacterial enteric pathogen were identified of 4966 cultures. E. Coli pathogens were the most prevalent of the isolates (34.6%) followed by S. aureus (9.6%), K. pneumoniae (7.1%) and E. aerogenes (6.8%). The susceptibility rates for the main isolates were: E. Coli - co-trimoxazole 30%, gentamicin 92%, amikacin 96%, cefotaxime 98% and nalidixic acid 89.6%; S. aureus – co-trimoxazole 51%, gentamicin 68%, amikacin 91%, cefotaxime 96% and nalidixic acid 92.7%; K. pneumoniae – co-trimoxazole 58%, gentamicin 82%, amikacin 95% cefotaxime 93% and nalidixic acid 82%. Conclusions: The micro-organism found most frequently was E. coli which has a lower sensitivity rate for co-trimoxazole than nalidixic acid (30% vs 89.6%) but has a higher sensitivity for third generation cephalosporins. The antibiotic sensitivity rates have decreased significantly over the study period, especially for co-trimoxazole. Recommendation: Do not use co-trimoxazole to treat acute diarrhoea due to E. coli.

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Last modified: December 10, 2001