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Biomedical subjects

A J Leach

Publications and source records attributed to A J Leach.

At least 19 recordsLinked to original sources
PubMed2006

Antibiotics for the prevention of acute and chronic suppurative otitis media in children.

BACKGROUND: Acute otitis media (AOM) is a common childhood illness. These middle ear infections may be frequent and painful. AOM may be associated with perforation of the tympanic membrane and can progress to chronic suppurative otitis media (CSOM). OBJECTIVES: To determine the effectiveness of long-term antibiotics (for longer than six weeks) in preventing any AOM, AOM with perforation and CSOM. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2006), MEDLINE (January 1966 to March Week 3 2006), OLD MEDLINE (1950 to 1965), EMBASE (1990 to December 2005) and the references of relevant studies. SELECTION CRITERIA: All randomised controlled trials of long-term (longer than six weeks) antibiotics versus placebo or no treatment for the prevention of AOM, AOM with perforation, or CSOM were eligible. DATA COLLECTION AND ANALYSIS: Two authors independently extracted the data for: any AOM; episodes of AOM; any recurrent AOM; episodes of illness; any side effects; any antibiotic resistance, as well as outcomes at end of intervention (any AOM); and following cessation of intervention (any AOM). For dichotomous outcomes, the summary risk ratio (fixed and random-effects models) was calculated. For rate outcomes, the summary incidence rate ratio was calculated. MAIN RESULTS: Sixteen studies involving 1483 children met our inclusion criteria. All studies enrolled children at increased risk of AOM, and in seven studies the children were prone to otitis media. The majority of studies were high quality and most (15 studies) reported data for our primary outcomes. None reported AOM with perforation or CSOM. Long-term antibiotics reduced any episode of AOM (13 studies, 1358 children, risk ratio (RR) 0.62, 95% CI 0.52 to 0.75; random-effects model) and number of episodes of AOM (12 studies, 1112 children, incidence rate ratio (IRR) 0.48, 95% CI 0.37 to 0.62; random-effects model). Approximately five children would need to be treated long term to prevent one child experiencing AOM whilst on treatment. Antibiotics prevented 1.5 episodes of AOM for every 12 months of treatment per child. Statistical heterogeneity was explored. Long-term antibiotics were not associated with a significant increase in adverse events (11 studies, 714 children, RR 1.99, 95% CI 0.25 to 15.89; random-effects model). AUTHORS' CONCLUSIONS: For children at risk, antibiotics given once or twice daily will reduce the probability of AOM while the child is on treatment. Antibiotics will reduce the number of episodes of AOM per year from around three to around 1.5. We believe that larger absolute benefits are likely in high-risk children. These conclusions were not affected by sensitivity analyses.

Acute Disease↗
PubMed2006

An overview of acute otitis media in Australian Aboriginal children living in remote communities.

Australian Aboriginal children experience early, persistent and severe middle ear infections. We conducted a review of the medical literature that addressed acute otitis media (AOM) in Australian Aboriginal children. Comparisons were made with the recent guidelines on the diagnosis and management of AOM prepared by the American Academies of Pediatrics and Family Physicians (AAP & AAFP 2004). Otitis media in Aboriginal children living in remote communities begins in the first 3 months of life following early bacterial colonisation. Young children with persistent signs of suppurative disease (bulging of the tympanic membrane or middle ear discharge) are probably most at risk of developing chronic suppurative otitis media.

Australia↗
PubMed2006

Clear not simple: an approach to community consultation for a maternal pneumococcal vaccine trial among Indigenous women in the Northern Territory of Australia.

PneuMum is a randomised controlled maternal vaccination trial, using 23-valent Pneumococcal Polysaccharide Vaccine (23vPPV) during the third trimester or at delivery compared to vaccination at 7 months post delivery. The primary outcomes are infant middle ear disease and nasopharyngeal pneumococcal carriage at 7 months of age. PneuMum is the first vaccine trial to be conducted among Indigenous people in the Northern Territory. We describe the study design and the approach taken to develop the PneuMum message in collaboration with key Indigenous stakeholders and then to communicate the PneuMum message with Indigenous communities and potential participants. We hope that these methods will provide a model for future research involving Indigenous communities to ensure Indigenous involvement in research and ultimate improvements in Indigenous health.

Adolescent↗
PubMed2006

Molecular characterisation of pneumococcal serotype 16F: Established predominant carriage and otitis media serotype in the 7vPCV era.

Young Australian Aboriginal children in remote communities experience very high rates of pneumococcal carriage and otitis media. Prior to introduction of the 7-valent pneumococcal conjugate vaccine (7vPCV, Prevenar), serotype 16F was an important type found in nasal and ear discharge swabs. Since commencement of pneumococcal immunisation for Aboriginal infants in 2001, 16F has become the predominant established serotype in carriage and otitis media in young Aboriginal children. BOX typing and multi-locus sequence typing revealed a diverse population of serotype 16F strains, and evidence of potential capsule switching from a vaccine serotype 4 to a serotype 16F.

Australia↗
PubMed2001

Molecular epidemiology of multiple drug resistant type 6B Streptococcus pneumoniae in the Northern Territory and Queensland, Australia.

The emergence of type 6B Streptococcus pneumoniae resistant to five antibiotics (penicillin, chloramphenicol, trimethoprim sulphamethoxazole, erythromycin and tetracycline) in both the Northern Territory and Queensland prompted an investigation of the genetic relatedness and patterns of migration of the isolates. Pulsed field gel electrophoresis of genomic DNA of 74 multiple drug-resistant (MDR) isolates cultured in both regions between August 1988 and June 1997 showed that 100% of MDR isolates from the Northern Territory and 96% of MDR strains from Queensland were genetically indistinguishable or closely related to the index strain. None of a further 65 type 6B isolates that were resistant to one or two, or susceptible to all of the above antibiotics, were clonally related to the MDR pneumococci. The geographical distribution of the MDR type 6B clone increased over time. The index strain, first isolated in Darwin in August 1988, was identified in Brisbane, 2900 km distant, less than 4 years later and subsequently in other Queensland centres. Surveillance programmes are important to monitor the emergence and spread of potentially invasive MDR pneumococcal clones in countries that are well serviced by air and road transport.

Bacterial Typing Techniques↗
PubMed2001

Perspectives on infective ear disease in indigenous Australian children.

Australian Aboriginal children experience the highest rates of bacterial respiratory diseases reported in the literature. Neonatal acquisition of multiple bacterial pathogenic species and strains predicts persistent and severe disease throughout childhood, particularly infective ear disease. The dynamics of bacterial nasopharyngeal colonization and transmission are poorly understood. The importance of host factors, bacterial competition and co-operation in the transition from asymptomatic carriage to disease are also uncertain. Treatment outcomes are poor, possibly due to the high density of bacterial infection following early age exposure, poor compliance and increasing levels of antibiotic resistance. The relationship between antibiotic use, clinical outcomes and bacterial resistance needs to be better understood in high-risk populations if the benefits associated with treatment are to be maximized. While there is an urgent need for vaccines, the early age of infection and the high rates of transmission and bacterial antigenic diversity mean these may also be less effective than predicted from studies in low-risk populations.

Age Distribution↗
PubMed1999

Otitis media in Australian Aboriginal children: an overview.

Remote and rural Australian Aboriginal children achieve lower standards of numeracy and literacy than their non-Aboriginal peers. The reasons are complex, but extraordinarily high rates of conductive hearing loss (> 50%) are, in part, responsible for poor classroom success. In addition to the burden of acute bacterial respiratory illness (highest rates of invasive pneumococcal disease in the literature), chronic disease affects virtually every young child. In the Aboriginal community studied, otitis media commenced within 3 months of birth for all infants, progressed to chronic suppurative otitis media in 60% and did not resolve throughout early childhood. Our findings, supported by mathematical modelling, show that the vicious cycle of endemic chronic otitis media is perpetuated by high carriage rates of multiple species and multiple types of respiratory bacterial pathogens, by high cross-infection rates and thus, by early age of pathogen acquisition and prolonged carriage. Long-term damage to respiratory mucosa, possibly linked to later chronic bronchitis and bronchiectasis, follows a constant series of infections by each of the concurrently held pathogens, without periods of recovery. Overcrowding and poor hygiene promote this vicious cycle. Medical and social options for intervention are limited by poor resources, low expectations for health and a complex biology that includes antibiotic resistant pneumococci.

Australia↗
PubMed1999

Middle ear effusion: rate and risk factors in Australian children attending day care.

There have been no previous longitudinal studies of otitis media conducted in non-Aboriginal Australian children. This paper describes the rate and risk factors for middle ear effusion (MEE) in children attending day care in Darwin, Australia. A prospective cohort study of 252 children under 4 years was conducted in 9 day care centres over 12 fortnights between 24 March and 15 September 1997. Tympanometry was conducted fortnightly and multivariate analysis used to determine risk factors predicting MEE. The outcome of interest was the rate of type B tympanograms per child detected in either ear at fortnightly examinations. After adjusting for clustering by child, MEE was detected on average 4.4 times in 12 fortnights (37% of all examinations conducted). Risk factors associated with presence of effusion were younger age, a family history of ear infection, previous grommets (tympanostomy tubes), ethnicity and the day care centre attended. A history of wheeze appeared protective. These effects were modest (RR 0.57-1.70). Middle ear effusion is very common in children attending day care in Darwin. This has clinical importance, since MEE during early childhood may affect optimal hearing, learning and speech development. There is little scope for modification for many of the risk factors for MEE predicted by this model. Further study of the day care environment is warranted.

Child Day Care Centers↗
PubMed1998

Low genetic diversity of Haemophilus influenzae type b compared to nonencapsulated H. influenzae in a population in which H. influenzae is highly endemic.

Immunization with Haemophilus influenzae type b (Hib) conjugate polysaccharide vaccines has dramatically reduced Hib disease worldwide. As in other populations, nasopharyngeal carriage of Hib declined markedly in Aboriginal infants following vaccination, although carriage has not been entirely eliminated. In this study, we describe the genetic characteristics and the carriage dynamics of longitudinal isolates of Hib, characterized by using several typing methods. In addition, carriage rates of nonencapsulated H. influenzae (NCHi) are high, and concurrent colonization with Hib and NCHi is common; we also observed NCHi isolates which were genetically similar to Hib. There is a continuing need to promote Hib immunization and monitor H. influenzae carriage in populations in which the organism is highly endemic, not least because of the possibility of genetic exchange between Hib and NCHi strains in such populations.

Amoxicillin↗
PubMed1998

British Forces Germany Health Service--satisfaction surveys of patients during 1996 and 1997 in one geographical location.

The Health Service in British Forces Germany has been subject to considerable change over the last two years. This study shows that the level of satisfaction with the Primary and Community Services in one area has remained consistently high over a twelve month period, even given the large number of changes that have been made to the working practices within the medical centres. This study also reports the fact that nearly 85% of patients who had attended a German hospital were satisfied with the service that had been provided.

Community Health Centers↗
PubMed1997

A prospective study of the impact of community-based azithromycin treatment of trachoma on carriage and resistance of Streptococcus pneumoniae.

In February 1995, single-dose azithromycin was given to children with trachoma and their household contacts who were children. For children with trachoma, rates of carriage of pneumococci immediately before treatment with azithromycin and 2-3 weeks, 2 months, and 6 months after treatment were 68% (54 of 79), 29% (11 of 38), 78% (29 of 37), and 87% (34 of 39), respectively. The proportion of carriage-positive children with azithromycin-resistant Streptococcus pneumoniae strains was 1 of 54 (1.9%) before treatment and then 6 of 11 (54.5%), 10 of 29 (34.5%), and 2 of 34 (5.9%) at follow-up visits. The profile of pneumococcal serotypes changed after azithromycin treatment. Azithromycin-resistant strains (serotypes 10F, 23A, and 45) were isolated from 1 (1.3%) of 79 pretreatment swab specimens, from 16 (21.3%) of 75 swab specimens collected up to 2 months after treatment, and from 2 (6%) of 32 obtained 6 months after treatment. Mathematical modeling showed a more rapid appearance of azithromycin-resistant pneumococcal strains in previously colonized children than in previously noncolonized children. Thus, it appears that the selective effect of azithromycin allowed the growth and transmission of preexisting azithromycin-resistant strains. More research is needed to clarify the clinical relevance and implications of azithromycin use.

Adolescent↗