Characterization of Ras k 1 a novel major allergen in Indian mackerel and identification of parvalbumin as the major fish allergen in 33 Asia-Pacific fish species.

BACKGROUND: Fish is a well-recognized cause of food allergy and anaphylaxis. The evolutionary and taxonomic diversity of the various consumed fish species pose a challenge in the identification and characterization of the major fish allergens critical for reliable diagnostics. Globally, fish is a rising cause of food allergy complicated by a large under-investigated variety of species as well as increasing global tourism and trade. This is the first comprehensive study on allergen profiles of heat-processed fish from Vietnam. OBJECTIVE: The aim of this study was to identify the major heat-stable allergens from frequently exported Asia-Pacific freshwater and marine fish and to characterize the major allergen parvalbumin (PV) from one of the most consumed and exported fish species from Asia, the Indian mackerel (Rastrelliger kanagurta). METHODS: Heated protein extracts from 33 fish species were separated by gel electrophoresis. PV isoforms were identified by immunoblotting utilizing 3 different PV-specific monoclonal and polyclonal antibodies and further characterized by mass spectrometry. IgE reactivity was investigated using sera from 21 patients with confirmed fish allergy. RESULTS: Heat-stable IgE-reactive PVs, with up to 5 isoforms per species, were identified in all 33 analysed fish species. In the Indian mackerel, 7 PV isoforms were identified by 2D-gel electrophoresis combined with mass spectrometric analyses. The amino acid sequence deduced from cDNA of the most expressed isoform showed a high identity (>90%) to PVs from 2 other mackerel species. CONCLUSIONS AND CLINICAL RELEVANCE: Different PVs were identified as the major heat-stable allergens in all 33 analysed freshwater and marine fish species from Vietnam, many of which are exported world-wide and 21 species that have never been investigated before. The Indian mackerel PV represents a novel fish allergen, now officially registered as Ras k 1. Improved diagnostics for fish allergy against Asia-Pacific species should be developed with focus on PV.

Rice: a common and severe cause of food protein-induced enterocolitis syndrome.

OBJECTIVE: To examine and compare the characteristics of food protein-induced enterocolitis syndrome (FPIES) caused by rice and cow's milk/soy. DESIGN: Retrospective study of children presenting with FPIES to the Children's Hospital at Westmead, NSW, Australia, over a 16-year period. RESULTS: There were 14 children with 26 episodes of rice FPIES compared with 17 children with 30 episodes of cow's milk (n = 10) or soy (n = 7) FPIES. Children with rice FPIES were more likely to have FPIES caused by other foods (36%) than children with FPIES caused by cow's milk/soy (0%). Rice caused more episodes of FPIES before a correct diagnosis was made (median 4 (range 1-4) vs median 2 (range 1-4)) and triggered more severe reactions with higher rates of intravenous fluid resuscitation (42% vs 17%) than reactions caused by cow's milk/soy. CONCLUSIONS: This study highlights the emerging importance of rice, a food commonly thought to be "hypoallergenic", as a significant trigger of FPIES. Paediatricians should be aware that rice not only has the potential to cause FPIES, but that such reactions tend be more severe than those caused by cow's milk/soy.

Paediatric anaphylaxis: a 5 year retrospective review.

OBJECTIVE: To describe the demographic characteristics, clinical features, causative agents, settings and administered therapy in children presenting with anaphylaxis. METHODS: This was a retrospective case note study of children presenting with anaphylaxis over a 5-year period to the Emergency Department (ED) at the Royal Children's Hospital, Melbourne. RESULTS: One-hundred and twenty-three cases of anaphylaxis in 117 patients were included. There was one death. The median age of presentation was 2.4 years. Home was the most common setting (48%) and food (85%) the most common trigger. Peanut (18%) and cashew nut (13%) were the most common cause of anaphylaxis. The median time from exposure to anaphylaxis for all identifiable agents was 10 min. The median time from onset to therapy was 40 min. Respiratory features were the principal presenting symptoms (97%). Seventeen per cent of subjects had experienced anaphylaxis previously. CONCLUSIONS: This is the largest study of childhood anaphylaxis reported. Major findings are that most children presenting to the ED with anaphylaxis are first-time anaphylactic reactions and the time to administration of therapy is often significantly delayed. Most reactions occurred in the home. Peanut and cashew nut were the most common causes of anaphylaxis in this study population, suggesting that triggers for anaphylaxis in children have not changed significantly over the last decade.

Cephalosporin resistant urinary tract infections in young children.

OBJECTIVE: To describe the antibiotic resistance pattern of bacteria causing urinary tract infection (UTI) in a cohort of Australian children under 6 years of age. METHODS: Data were collected over a 12-month period from children under 6 years of age with a provisional diagnosis of UTI made in the Emergency Department of Sunshine Hospital, Victoria. RESULTS: During the study period 100 culture-proven UTI were identified in 97 children. Three children had two episodes. Out of the 100 episodes, 39% were male, 56% were under 12 months of age at presentation and 61% were managed as outpatients. Clinical features were non-specific in the majority of cases. Hydronephrosis and vesicoureteric reflux was detected in 5.5% and 28.6%, respectively, of children with their first investigated UTI. A single bacterial isolate was cultured from 97 urines and two from three samples. Escherichia coli (n = 90) and Proteus mirabilis (n = 5) were the most common isolates. In vitro resistance to ampicillin/amoxycillin was found in 52% of isolates, to trimethoprim in 14% and to cephalothin/cephalexin in 24%. This resistance rate to first generation cephalosporins is the highest reported to date in adult or paediatric UTI in Australia. CONCLUSIONS: Ampicillin/amoxycillin or cephalothin/cephalexin may not be the optimal choice of antibiotic for the empiric treatment of UTI in this and possibly other paediatric populations.

Sepsis in neonatal intensive care in the late 1990s.

AIM: To determine the incidence and clinical characteristics of sepsis in ventilated infants from an Australian neonatal intensive care unit (NICU) in the late 1990s. METHODS: Demographic data was collected from babies requiring assisted ventilation (AV) over the 6-month period from 1 July to 31 December 1998. Sepsis was divided into early onset sepsis (EOS; " 72 h of age) and late onset sepsis (LOS; >72 h of age), including both definite (culture-proven + abnormal markers) and probable (culture negative + abnormal markers) episodes. RESULTS: Two hundred and eleven babies required AV over this period. Of these, 64 (30.3%) had at least one infection, with 85 episodes of sepsis (40.3 episodes per 100 admissions requiring AV). There were 22 babies with 22 episodes of EOS, and 45 with 63 episodes of LOS. Three babies had both EOS and LOS. The rate of EOS was 10.4 infected infants (10.4 infections per 100 admissions requiring AV). The rate of LOS was 21.3 infected infants (29.9 infections per 100 admissions requiring AV). The rates of both EOS and LOS were higher than previously reported by Australian studies in the early 1990s. In both EOS and LOS, risk factors for infection were common. Group B streptococcus was the commonest cause of definite EOS. The mortality rate from sepsis in the EOS group was 14% (3/22). Coagulase-negative staphylococci were the commonest cause of LOS. The mortality rate from sepsis in the LOS group was 11% (5/45). CONCLUSIONS: EOS and LOS are significant problems in ventilated NICU infants in the late 1990s.

Interleukin-6 and interleukin-8 in newborn bacterial infection.

The objective of this study is to determine the plasma concentrations and diagnostic accuracy of interleukin-6 (IL-6) and interleukin-8 (IL-8) in newborn infection. One hundred and one newborn infants with clinical signs of infection during their primary hospitalization were investigated with the minimum of a blood culture, C-reactive protein (CRP), full blood examination (FBE), and cytokine concentrations (IL-6 and IL-8). Infection in infants was classified without knowledge of cytokine levels into four groups-definite (n = 11), probable (n = 12), uncertain (n = 52), and nil (n = 26). The median concentrations of IL-6 and IL-8 were significantly higher in the definitely infected group compared with the other three groups (p <0.05). At the cut-off concentration of highest accuracy, IL-6 (>175 pg/mL) and IL-8 (>28 pg/mL) had similar sensitivities (80 and 82%, respectively) and specificities (91 and 81%, respectively). Cut-off concentrations could be identified with improved sensitivities (90% for IL-6 and 100% for IL-8) that maintained specificity >50%. However, the confidence intervals were wide for all sensitivities and specificities. IL-6 and IL-8 had little diagnostic accuracy in infants with probable infection. IL-6 and IL-8 concentrations increase early in newborn infants with definite infection.