Paediatrics (RCH) - Research Publications
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ItemAs a bacterial culture medium, citrated sheep blood agar is a practical alternative to citrated human blood agar in laboratories of developing countriesRussell, FM ; Biribo, SSN ; Selvaraj, G ; Oppedisano, F ; Warren, S ; Seduadua, A ; Mulholland, EK ; Carapetis, JR (AMER SOC MICROBIOLOGY, 2006-09-01)Human blood agar (HuBA) is widely used in developing countries for the isolation of bacteria from clinical specimens. This study compared citrated sheep blood agar (CSBA) and HuBA with defibrinated horse blood agar and defibrinated sheep blood agar (DSBA) for the isolation and antibiotic susceptibility testing of reference and clinical strains of Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus. Reference and clinical strains of all organisms were diluted in brain heart infusion and a clinical specimen of cerebrospinal fluid and cultured on all agars. Viable counts, colony morphology, and colony size were recorded. Susceptibility testing for S. pneumoniae and S. pyogenes was performed on defibrinated sheep blood Mueller-Hinton agar, citrated sheep blood Mueller-Hinton agar (CSB MHA), and human blood Mueller-Hinton agar plates. For all organisms, the colony numbers were similar on all agars. Substantially smaller colony sizes and absent or minimal hemolysis were noted on HuBA for all organisms. Antibiotic susceptibility results for S. pneumoniae were similar for the two sheep blood agars; however, larger zone sizes were displayed on HuBA, and quality control for the reference strain failed on HuBA. For S. pyogenes, larger zone sizes were demonstrated on HuBA and CSBA than on DSBA. Poor hemolysis made interpretation of the zone sizes difficult on HuBA. CSBA is an acceptable alternative for the isolation of these organisms. The characteristic morphology is not evident, and hemolysis is poor on HuBA; and so HuBA is not recommended for use for the isolation or the susceptibility testing of any of these organisms. CSB MHA may be suitable for use for the susceptibility testing of S. pneumoniae.
ItemThe burden of hospitalised rotavirus infections in FijiJenney, A ; Tikoduadua, L ; Buadromo, E ; Barnes, G ; Kirkwood, CD ; Boniface, K ; Bines, J ; Mulholland, K ; Russell, F (ELSEVIER SCI LTD, 2009-11-20)Rotavirus is the most common cause of acute severe dehydrating diarrhoea in young children worldwide. We describe the burden of rotavirus disease and the rotavirus types causing it in the largest city in Fiji. During 2006 and 2007, 592 children under 5 years of age were admitted to hospital in Suva, Fiji with acute diarrhoea. Of the 454 children for whom a stool specimen was tested, 39% were positive for rotavirus and the predominant strain found was the serotype G3[P8]. There is a significant burden of disease due to rotavirus in Fiji and the introduction of rotavirus vaccines into the national immunization schedule may drastically reduce inpatient diarrhoeal disease.
ItemImmunogenicity following one, two, or three doses of the 7-valent pneumococcal conjugate vaccineRussell, FM ; Balloch, A ; Tang, MLK ; Carapetis, JR ; Licciardi, P ; Nelson, J ; Jenney, AWJ ; Tikoduadua, L ; Waqatakirewa, L ; Pryor, J ; Byrnes, GB ; Cheung, YB ; Mulholland, EK (ELSEVIER SCI LTD, 2009-09-18)The aim was to identify an appropriate infant pneumococcal vaccination strategy for resource poor countries. Fijian infants received zero, one, two, or three doses of 7-valent pneumococcal conjugate vaccine (PCV) in early infancy. Following three PCV doses, geometric mean concentration (GMC) to all seven serotypes were > or = 1.0 microg/mL, and >85% of children achieved antibody levels > or = 0.35 microg/mL at 18 weeks. Following two doses, GMC were lower for 6B, 14, and 23F, but higher for 19F compared with three doses. Following a single dose, significant responses were seen for all serotypes post-primary series compared with the unvaccinated. By 12 months, differences between two and three doses persisted for serotype 14 only. Although GMC following three doses are higher than after two doses, the differences were small. A single dose may offer some protection for most serotypes.
ItemPrevention of otitis media by vaccinationRussell, F ; Mulholland, K (ADIS INT LTD, 2002-01-01)Otitis media (OM) is one of the commonest infections in childhood and a frequent reason for prescribing antibacterials in infancy. However, the increase in prevalence of antibacterial-resistant respiratory bacterial pathogens has not been matched by the development of new antibacterial agents. Bacterial vaccine strategies aim to prevent OM directly and to reduce nasopharyngeal carriage of pneumococci, thereby reducing the likelihood of developing acute OM. Complete protection against OM would require an approach targeting both bacterial and viral agents. Immunisation with a pneumococcal conjugate vaccine provides protection against acute OM caused by pneumococcal serotypes included in the vaccine, reduces serotype-specific pneumococcal carriage, and reduces carriage of penicillin-resistant pneumococci. However, an increase in non-vaccine serotype OM has been observed in vaccinated children, which may limit the overall effectiveness of this vaccine. New vaccines targeting non-typable Haemophilus influenzae and Mycoplasma catarrhalis are in the early stages of development. Efficacy studies with influenza vaccine have shown the most promising results to date in terms of overall reduction in OM episodes. A more substantial reduction in the burden of OM in childhood would require a combination of vaccines that are effective against the bacterial and viral pathogens involved and that can be administered early in infancy.
ItemHigh incidence of Haemophilus influenzae type b infection in children in Pacific Island countriesRussell, FM ; Carapetis, JR ; Mansoor, O ; Darcy, A ; Fakakovi, T ; Metai, A ; Potoi, NT ; Wilson, N ; Mulholland, EK (UNIV CHICAGO PRESS, 2003-12-15)The Haemophilus influenzae type b (Hib) disease burden among children <5 years old in 4 Pacific island countries (PICs) was estimated. The incidence of confirmed Hib meningitis was calculated using the numbers of culture-confirmed isolates. In addition, the World Health Organization (WHO) Hib Rapid Assessment Tool (RAT) was used to estimate the true Hib meningitis incidence and the number of Hib meningitis and pneumonia cases, as well as the number of deaths due to Hib meningitis and pneumonia. The Hib meningitis annual incidence in 3 PICs was 70-84 cases per 100,000 children <5 years old. For PICs, the RAT is likely to overestimate the Hib pneumonia burden, as it assumes a 5 : 1 ratio of Hib pneumonia to Hib meningitis. The true ratio is likely to be 1 : 1. The high Hib disease burden and the relative cost-effectiveness of Hib vaccine make the introduction of Hib vaccine a good investment for PICs, costing US1000 dollars-US10,000 dollars for each death prevented--a number that ignores savings from reductions in the cost of treatment.
ItemChest x-ray-confirmed pneumonia in children in FijiMagree, HC ; Russell, FM ; Sa'aga, R ; Greenwood, P ; Tikoduadua, L ; Pryor, J ; Waqatakirewa, L ; Carapetis, JR ; Mulholland, EK (WORLD HEALTH ORGANIZATION, 2005-06-01)OBJECTIVE: To calculate the incidence and document the clinical features of chest X-ray- (CXR-) confirmed pneumonia in children aged between 1 month and 5 years living in Greater Suva, Fiji. METHODS: A retrospective review was undertaken of children aged between 1 month and 5 years with a discharge diagnosis suggesting a lower respiratory tract infection (LRTI) admitted to the Colonial War Memorial Hospital in Suva, Fiji, in the first 10 days of each month from 1 January 2001 to 31 December 2002. Clinical data were collected and CXRs were reread and classified according to WHO standardized criteria for CXR-confirmed pneumonia. FINDINGS: Two hundred and forty-eight children with LRTI met the inclusion criteria. CXRs were obtained for 174 (70%) of these cases, of which 59 (34%) had CXR-confirmed pneumonia. The annual incidence of CXR-confirmed pneumonia was 428 cases per 100,000 children aged between 1 month and 5 years living in Greater Suva. If a similar proportion of the children for whom CXRs were unavailable were assumed to have CXR-confirmed pneumonia, the incidence was 607 per 100,000. The incidence appeared to be higher in Melanesian Fijian than Indo-Fijian children. The case-fatality rate was 2.8% in all children with LRTI, and 6.8% in those with CXR-confirmed pneumonia. CONCLUSION: This is the first study to document the incidence of CXR-confirmed pneumonia in a Pacific Island country, and demonstrates a high incidence. A significant proportion of hospital admissions of children with LRTI are likely to be preventable by the introduction of pneumococcal conjugate vaccine.