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M Gratten

Publications and source records attributed to M Gratten.

At least 19 recordsLinked to original sources
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↗
PubMed2000

Conjugate pneumococcal vaccines for aboriginal children in Australia.

Research indicates a high burden of pneumococcal disease and great potential benefits of conjugate vaccines in Indigenous Australian children, who should have high priority for delivery of these vaccines. Incidence of invasive pneumococcal disease in Indigenous people in central Australia is the highest reported in the world (2053 per 100,000 persons per year in those aged under two years). Acute respiratory infection is a major cause of morbidity in Indigenous children in rural and remote areas. Early pneumococcal colonisation of the nasopharynx and high rates of carriage are seen in Indigenous children, and are probably related to their high rates of ear disease. Current seven-valent conjugate vaccines are likely to cover about two-thirds of invasive isolates in Indigenous Australian children; 11-valent vaccines will cover a higher proportion. Questions remain about the best vaccine carrier protein and the likely impact of vaccine on ear disease, pneumococcal carriage and antibiotic resistance.

Australia↗
PubMed1999

Molecular characterization of a globally distributed lineage of serotype 12F Streptococcus pneumoniae causing invasive disease.

These studies have identified a major genetic lineage of capsule serotype 12F Streptococcus pneumoniae, which has maintained two different types of the pneumococcal surface protein A (PspA) virulence factor and caused invasive disease in geographically disjoint locations. Twenty outbreak strains from a Texas jail and Maryland day care center and 16 reference strains from Texas, Maryland, Washington, Michigan, Oklahoma, Missouri, Alaska, and Australia were examined. Although the Texas and Maryland outbreak strains were indistinguishable by IS1167 and boxA genotyping procedures, all strains examined were members of a genetically similar lineage. The microevolutionary history of pspA differed from that of the overall genetic background of the strains. Taken together, these findings suggested that the Texas and Maryland outbreaks were caused by different clones of a major genetic lineage of serotype 12F pneumococci, within which at least one PspA has been acquired via localized genetic recombination.

Amino Acid Sequence↗
PubMed1999

Etiology of acute lower respiratory tract infection in Central Australian Aboriginal children.

BACKGROUND: Aboriginal children in central Australia have attack rates for acute lower respiratory tract infection (ALRI) that are similar to those in developing countries. Although mortality rates are much lower than in developing countries, morbidity is high and ALRI is still the leading cause of hospitalization. However, there are no data on the etiology of ALRI in this population. METHODS: We prospectively studied 322 cases of ALRI in 280 Aboriginal children admitted to the hospital. Blood, urine and nasopharyngeal aspirate samples were examined for evidence of bacterial, viral and chlamydial infection. RESULTS: The combination of blood culture, viral studies and chlamydial serology provided at least 1 etiologic agent in 170 of 322 (52.5%) cases. Assays for pneumolysin immune complex and pneumolysin antibody increased etiologic diagnosis to 219 (68.0%). Blood cultures were positive in 6% but pneumolysin immune complex and pneumolysin antibody studies were positive in one-third of cases. Evidence of viral infection was present in 155 (48%) of cases compared with 12% in controls (P < 001). There were only 7 possible cases and 2 definite cases of Chlamydia trachomatis and 3 cases of Chlamydia pneumoniae. Coinfection was common in these children. CONCLUSION: These findings have implications for both standard treatment protocols and vaccine strategies. The high rate of coinfection may make it difficult to develop simple clinical predictors of bacterial infection. In the setting of a developed country with efficient patient evacuation services, management algorithms that focus on disease severity and need for hospital referral will be most useful to health staff in remote communities. Pneumococcal conjugate vaccines will be required to reduce the high attack rate of pneumococcal disease.

Australia↗
PubMed1999

Nasopharyngeal carriage of penicillin-resistant Streptococcus pneumoniae among children with acute respiratory tract infections in Thailand: a molecular epidemiological survey.

The prevalence of penicillin-resistant Streptococcus pneumoniae in Thailand has dramatically increased over the last decade. During a national survey, which was conducted from 1992 to 1994, 37.2% of the pneumococci isolated from the nasopharynges of children with acute respiratory tract infections were penicillin resistant (MIC, >/=0.1 microg/ml). In order to investigate the prevalence and clonal relatedness of nasopharyngeal carriage of penicillin-resistant S. pneumoniae in Thailand, a molecular epidemiological survey was undertaken. To this end, 53 penicillin-resistant pneumococcal isolates from children who suffered from acute respiratory tract infections and who originated from five distinct regions of the country were characterized in detail. DNA fingerprint analysis demonstrated 13 clusters, i.e., genotypes shared by two or more strains, and 14 unique genotypes. The cluster size varied from 2 (nine clusters) to 11 strains (one cluster). Six of the 13 restriction fragment end labeling clusters consisted of two or more distinct serotypes, indicating frequent horizontal transfer of capsular genes. Geographical distribution of the genotypes among the five regions of Thailand demonstrated that only four genetic clusters were restricted to single areas of the country, whereas the other nine clusters represented isolates collected in two or more districts. These observations demonstrate that the majority of the genetic clusters are spread throughout the country. The most predominant genetic cluster, representing 21% of the isolates, was identical to the Spanish pandemic clone 23F. In addition, the second largest cluster matched the Spanish-French international clone 9V. These data indicate that the genetic clones 23F and 9V, which are widely spread throughout the world, are the most predominant multidrug-resistant pneumococcal clones in Thailand. Therefore, we conclude that these pandemic clones are primarily responsible for the increase in the prevalence of pneumococcal penicillin resistance in Thailand.

Bacterial Typing Techniques↗
PubMed1998

Seroepidemiology of invasive pneumococcal disease in Queensland, 1990 to 1997.

Serotypes responsible for 842 cases of invasive pneumococcal disease in Queensland between February 1990 and October 1997 were identified. Type 14 caused 37.5% of episodes in children aged 0-4 years and 19.2% of adult cases. Types 6A, 6B, 14, 18C, and 19F were significantly more frequent in young children while types 3, 4, 7F, 9V and 23F predominated in adults. The regional incidence of type 14 and 7F disease differed significantly in Southeast and Far North Queensland. Coverage for 87% of children aged less than 5 years in this study would be provided by a recently advocated polysaccharide-protein conjugate vaccine containing capsular antigens of types 4, 6B, 9V, 14, 18C, 19F and 23F. Similarly, more than 90% of adults would be covered by the currently available 23- valent polysaccaride vaccine.

Adolescent↗
PubMed1997

Emergence of further serotypes of multiple drug-resistant Streptococcus pneumoniae in Queensland.

We describe 27 cases of multiple drug-resistant pneumococcal infection in Queensland children (7 cases) and adults (20 cases), between February 1995 and October 1996. Seven patients had invasive disease. Serotypes were those commonly associated with paediatric infections and included types 19F (15 strains), 14 (6), 23F (4), 6A (1) and 19A (1). No rifampicin or vancomycin resistance was encountered. However, pneumococci fully resistant to cotrimoxazole, erythromycin and tetracycline were isolated from 25 of 27 cases (93%). Strains with high level resistance to penicillin and chloramphenicol were also recovered from 16 (59%) and 19 (70%) patients respectively. Twelve of 16 penicillin-resistant isolates showed intermediate resistance to ceftriaxone and two strains were fully resistant to this antibiotic. Clones of types 19F and 14 pneumococci, each with two distinctive resistance patterns, appear to be established in south-east Queensland.

Adult↗
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↗
PubMed1997

Susceptibility of pneumococcal carriage isolates to penicillin provides a conservative estimate of susceptibility of invasive pneumococci.

OBJECTIVE: Because of its practical importance for public health monitoring in developing countries, we aimed to determine whether susceptibility to penicillin of pneumococci isolated from the upper respiratory tract (URT) is representative of the susceptibility of pneumococci causing pneumonia in children. METHOD: The serogroup distribution and minimum inhibitory concentration of penicillin for 56 and 90 isolates from blood and cerebrospinal fluid, respectively, were compared with those of 833 pneumococcal carriage isolates from Papua New Guinean children. These included 154 and 98 strains from bacteremic and nonbacteremic hospitalized patients with pneumonia, respectively, 350 from outpatients with respiratory infections and 176 and 55, respectively, from children in a community-based study who were healthy or sick with pneumonia. RESULTS: Proportions of pneumococci intermediately resistant to penicillin were comparable in the URT and blood (60%) in 1985 through 1987 when serogroup distributions in the two sites were similar. However, penicillin resistance was higher in the URT (75%) than blood (44%) in 1980 through 1984 when the less frequently carried, less resistant serogroups (1 to 5, 7 to 12, 45 and 46) accounted for a high proportion of bacteremic strains. CONCLUSIONS: URT isolates from any group of sick or healthy children could provide a conservative estimate of antimicrobial susceptibility of invasive strains and is a practical way of monitoring susceptibility as well as evaluating the continued effectiveness of standard antibiotic therapy. If there was cause for concern, it would then be necessary to examine invasive isolates.

Carrier State↗
PubMed1997

Pneumococcal vaccination: an important strategy to prevent pneumonia in Aboriginal and Torres Strait Island adults.

The objective of the study was to examine the appropriateness of the National Health and Medical Research Council (NHMRC) recommendations concerning pneumococcal vaccination for Aboriginal and Torres Strait Island adults. Laboratory surveillance of invasive pneumococcal disease identified 95 cases acquired by adults 15 years of age and over in Far North Queensland from 1992 to 1995. The most common diagnosis was pneumonia (77 per cent). Sixty-one cases (64 per cent) occurred in Aboriginal and Torres Strait Island adults, who acquired the disease at a younger age (mean 40 years) than did other adults (mean 50 years). Most (93 per cent) of the Aboriginal and Torres Strait Island adults had at least one of the pre-existing medical conditions in the NHMRC criteria for pneumococcal vaccination. The most common was 'alcohol abuse' (62 per cent). Fifty-three (93 per cent) of the pneumococcal isolates from the Aboriginal and Torres Strait Island adults who had pre-existing conditions were serotyped. Fifty (94 per cent) belonged to types included in the currently available pneumococcal vaccine. We conclude that the NHMRC recommendations for pneumococcal vaccination are appropriate, considering the pattern of invasive pneumococcal disease that occurs in Aboriginal and Torres Strait Island adults in Far North Queensland. Because pneumococcal vaccination can reduce the pneumonia-associated morbidity and premature mortality experienced by Aboriginal and Torres Strait Island adults, the vaccine should be offered routinely to those considered to be at risk, particularly young men who have recently begun to consume hazardous amounts of alcohol, and recently diagnosed diabetics.

Adolescent↗
PubMed1996

Distribution of capsular types and antibiotic susceptibility of invasive Streptococcus pneumoniae isolated from aborigines in central Australia.

Streptococcus pneumoniae strains isolated from 203 episodes of invasive disease in central Australian Aborigines were studied. Capsular types from children aged 0 to 4 years (n = 89) belonged most commonly to types 14, 6B, 9V, 4, 18C, and 19F, which together accounted for 67% of the pediatric strains. In adults (n = 98), types 1, 7F, 3, 4, 12F, and 8 contributed 68% of the isolates. Of 114 pneumococci from patients 5 years and older, 102 (89.5%) were types represented in the 23-valent pneumococcal polysaccharide vaccine. The MICs of five antibiotics were determined for 201 strains by using the E-Test (AB Biodisk). No chloramphenicol or ceftriaxone resistance was found, but 46 strains (22.9%) showed diminished susceptibility to one or more of the drugs penicillin, erythromycin, and trimethoprim-sulfamethoxazole. Penicillin resistance occurred in 15.4% of all isolates tested but only within the intermediate range (0.1 to 1.0 microgram/ml). Resistance to trimethoprimsulfamethoxazole affected 13.9% of the pneumococci tested. All type 23F and most type 19F organisms were resistant to one or more antibiotics. Resistance was significantly more common in pediatric isolates than in those from adults (chi 2(1) = 14.1; P < 0.001).

Adolescent↗
PubMed1995

Invasive pneumococcal disease in central Australia.

OBJECTIVES: To document the incidence, case fatality, clinical and demographic features of invasive pneumococcal disease in central Australia. DESIGN: Invasive isolates from the regional central laboratory were prospectively recorded over five years and case notes retrospectively reviewed. Population denominators were calculated from national Census data from 1986 and 1991. RESULTS: The population estimates for the region were 14,568 for Aboriginals and 28,680 for non-Aboriginals. There were 185 episodes of invasive pneumococcal disease over the five years, 162 (87.5%) in Aboriginals and 23 (12.5%), in non-Aboriginals. The incidence in Aboriginal children under two years of age was 2052.7 per 100,000 and for those 20-59 years was 178.2 per 100,000. The relative risk in Aboriginals compared with non-Aboriginals was 10.8 (95% CI, 5.6-20.7; P < 0.0001) for those aged 0-4 years and 20.4 (95% CI, 9.7-42.5; P < 0.0001) for those 15-59 years. Forty-one Aboriginal adults aged over 14 (62%) had at least one conventional risk factor for pneumococcal disease; alcohol abuse was present in 27 (41%). There were 13 Aboriginal deaths and the case fatality rose from 2% in those under four years to 40% for those over 59 years. CONCLUSIONS: Central Australian Aboriginals have the highest incidence of invasive pneumococcal disease reported. The rate for children under two years is 59 to 80 times the rates for children in the United States and Sweden. These data have implications for improving vaccine use, health service delivery and environmental health in Aboriginal communities.

Adolescent↗
PubMed1994

Comparison of goat and horse blood as culture medium supplements for isolation and identification of Haemophilus influenzae and Streptococcus pneumoniae from upper respiratory tract secretions.

The results of this study show that goat blood as a culture medium supplement is as supportive as horse blood for the isolation and identification of Haemophilus influenzae and Streptococcus pneumoniae from clinical material. Care is required in the preparation of goat blood chocolate agar to ensure that a thermolabile growth inhibitor of NAD-dependent Haemophilus species is eliminated.

Animals↗
PubMed1994

Upper airway carriage by Haemophilus influenzae and Streptococcus pneumoniae in Australian aboriginal children hospitalised with acute lower respiratory infection.

When nasopharyngeal secretions from 171 Australian Aboriginal children hospitalized with acute lower respiratory tract infections (ALRI) were cultured selectively for Streptococcus pneumoniae and Haemophilus influenzae, 136 (79.5%) and 151 (88.3%) children yielded 166 and 254 isolates of S. pneumoniae and H. influenzae, respectively. In colonized subjects multiple populations of S. pneumoniae (20% of carriage-positive patients) and H. influenzae (55%) were common. Pneumococci belonging to 27 types or groups were identified. H. influenzae serotype b colonized 16.4% of all children studied. More than one half of 152 children tested were excreting antibiotics at the time of admission to hospital. Significantly fewer children with serum antibiotic residues were colonized with S. pneumoniae than were antibiotic free children. Antibiotic usage had no measurable impact on the isolation rate of H. influenzae.

Acute Disease↗
PubMed1993

An outbreak of serotype 1 Streptococcus pneumoniae infection in central Australia.

An outbreak of serotype 1 Streptococcus pneumoniae infection involving both adults and children occurred in central Australia during the winter months of 1991. Eighteen patients, mainly Aboriginal men, presented with culture-positive serotype 1 bacteraemic pneumonia. In this group, 11 of 12 adults for whom medical records were available were alcohol dependent. Thirteen children who were separately studied were hospitalised with acute lower respiratory tract infection: none had bacteraemia but all had upper airway colonisation by type 1 pneumococci. Antibiotics taken by 8 of the 13 children before admission to hospital may have compromised the isolation of type 1 pneumococci from blood cultures. Since the availability of antibiotics, epidemic pneumococcal infection is infrequent and has not been reported in Australia. In three outbreaks of type 1 disease recorded elsewhere crowding and alcoholism were identified as contributory factors. In the 16 month period before this outbreak none of 162 strains of pneumococci isolated from blood (32 strains) and nasopharyngeal secretions (130 strains) from Aborigines with acute lower respiratory tract infection and meningitis in the Alice Springs region were serotype 1 organisms.

Adult↗
PubMed1993

Acquisition and invasiveness of different serotypes of Streptococcus pneumoniae in young children.

Rates of acquisition and mean duration of nasal carriage of different serotypes of Streptococcus pneumoniae have been estimated by fitting a stochastic model to longitudinal carriage data in children from Papua New Guinea. Immunogenicity and two indices of relative invasiveness were determined for each serotype. Immunogenic serotypes were less frequently acquired and were carried for shorter periods, but no relationship between immunogenicity and invasiveness was apparent using either index of invasiveness. Frequent invasion was associated with a high acquisition rate and high frequency and prolonged duration of carriage. Carriage studies can provide a broad indication of which serotypes cause invasive disease but not the proportion of disease due to individual serotypes; some serotypes which cause invasive disease (e.g. serotype 46) are not found even in extensive carriage studies. The antibiotic resistance of carriage organisms, however, does approximate the resistance patterns of invasive organisms and thus may be used to monitor changing patterns of antimicrobial susceptibility in the community.

Antibodies, Bacterial↗
PubMed1991

The bacteriology of acute pneumonia and meningitis in children in Papua New Guinea: assumptions, facts and technical strategies.

Acute respiratory infections in children aged less than 5 years in the Eastern Highlands of Papua New Guinea were investigated bacteriologically for 10 years from November 1978. Haemophilus influenzae and Streptococcus pneumoniae were responsible for 73% of all bacteria cultured from lung aspirate (83 samples), 85.5% from blood (1024 samples) and 92% from cerebrospinal fluid (155 samples). Nonencapsulated H. influenzae was carried by up to 90% of children and was the predominant haemophilus type cultured from lung tissue. Mixed infections of the lung with two types of H. influenzae (8 cases) and both H. influenzae and S. pneumoniae (18 cases), commonly together with other organisms of questionable pathogenicity, reflected the proximity of this organ to the upper respiratory tract. Serotype b accounted for 62% and 82% of H. influenzae isolated from bacteraemic pneumonia and meningitis cases, respectively. Polymicrobic bacteraemic pneumonia occurred in 16 children. Both H. influenzae and S. pneumoniae establish dense, unregulated long-term colonization in the nasopharynx during the neonatal period. Each inhibit autochthonous microflora by mechanisms that are currently unclear. Infections with two or more types occur in 30% (S. pneumoniae) and 60% (H. influenzae) of carriage-positive children. 70-75% of H. influenzae and S. pneumoniae isolates from blood concomitantly colonize the upper respiratory tract. Intense exposure of Papua New Guinean children to penicillin at all levels of health care since the 1940s has resulted in widespread relative resistance among pneumococci to this antibiotic. Resistant strains are now found in 32 serotypes, and in children penicillin resistance is present in 75% of all carriage strains and 52% and 22% of blood and cerebrospinal fluid isolates, respectively. Penicillin-susceptible and resistant pneumococcal serotypes commonly coexist in multiply populated carriage sites. Resistance to betalactam antibiotics is rare among H. influenzae strains and resistance has not been detected in either H. influenzae or S. pneumoniae to chloramphenicol, erythromycin, tetracycline or cotrimoxazole. It should not be assumed that the technology of respiratory bacteriology as it is practised in developed countries can be transferred to the third world for utilization in paediatric aetiology and carriage studies. Respiratory bacteriology strategies as they evolved in Goroka were subject to diverse influences. The type distribution of the major causative agents defied fashionable beliefs, generated the need for more precise epidemiological differentiation and, by virtue of their carriage density, cultural properties and response to commonly used antibiotics, required the introduction or development of compatible diagnostic procedures.

Acute Disease↗