Salmonella in the tropical household environment--Everyday, everywhere.

OBJECTIVES: To determine the prevalence of Salmonella in the environment of case and control houses, and compare serovars isolated from cases and their houses. METHODS: From 2005 to 2008, we tested samples from houses of 0-4 year old cases and community controls in Darwin and Palmerston for Salmonella. Case isolates were compared with environmental isolates. S. Ball and S. Urbana isolates were compared using Multiple Amplification of Phage Locus Typing (MAPLT) and Multiple-Locus Variable number of tandem repeat Analysis (MLVA). RESULTS: Salmonella were found in 47/65 (72%) case houses and 18/29 (62%) control houses; these proportions were not significantly different. In 21/47 (45%) houses, case and environmental isolates (from animal faeces, soil and vacuums) were indistinguishable. Multiple serovars were isolated from 20 (31%) case and 6 (21%) control houses. All but one environmental isolate are known human pathogens in the Northern Territory (NT). Each of the four pairs of S. Ball and S. Urbana were indistinguishable. CONCLUSIONS: Animal faeces were the most likely source of salmonellosis in cases. The similar prevalence of house isolates suggests that Salmonella is ubiquitous in this environment. The distinction of S. Ball and S. Urbana subtypes enabled linkage of human illness to environmental exposure. Environmental contamination with Salmonella is an important source of sporadic infection in children in the tropics.

General practitioners' knowledge and attitudes to contact tracing for genital Chlamydia trachomatis infection in North Queensland.

INTRODUCTION: Most diagnoses of genital chlamydia infection in Queensland are made by general practitioners (GPs). This study aimed to assess GP attitudes to and knowledge of contact tracing in rural North Queensland. METHOD: A single page questionnaire mailed to a database of 65 GPs in May 2007. RESULTS: Nearly all respondents (42/43, 97.7%) 'always' or 'mostly' told patients to advise their contacts to seek medical treatment. More than half (24/44, 54.5%) felt that contact tracing was 'sometimes' or 'never' the responsibility of GPs. Around half of respondents (19/39, 48.7%) thought that the local public health unit staff were conducting contact tracing, which is not actually the case. CONCLUSION: There is lack of clarity surrounding the respective roles and responsibilities of sexual health units, public health units and GPs regarding contact tracing for chlamydia infection. IMPLICATIONS: GPs would benefit from education clarifying current contact tracing procedures, methods and resources.

Characterization of Chlamydia trachomatis omp1 genotypes detected in eye swab samples from remote Australian communities.

Chlamydia trachomatis conjunctival samples collected over a 6-month period from individuals with clinical signs of trachoma and located in remote communities in the Australian Northern Territory were differentially characterized according to serovar and variants. The rationale was to gain an understanding of the epidemiology of an apparent increased prevalence of acute trachoma in areas thought to be less conducive to this disease. Characterization was performed through sequencing of a region of the omp1 gene spanning the four variable domains and encoding the major outer membrane protein. Nucleotide and deduced amino acid sequences were genotyped by using a BLAST similarity search and were examined by phylogenetic analyses to illustrate evolutionary relationships between the clinical and GenBank reference strains. The predominant genotype identified corresponded to that of serovar C (87.1%), followed by the genotype corresponding to serovar Ba (12.9%). All nucleotide and amino acid sequences exhibited minor levels of variation with respect to GenBank reference sequences. The omp1 nucleotide sequences of the clinical samples best aligned with those of the conjunctival C. trachomatis reference strains C/TW-3/OT and Ba/Apache-2. All clinical samples (of serovar C) exhibited four or five nucleotide changes compared with C/TW-3/OT, while all serovar Ba samples had one or two nucleotide differences from Ba/Apache-2. Phylogenetic analyses revealed close relationships between these Northern Territory chlamydial samples and the respective reference strains, although the high proportion of sequence variants suggests an evolutionarily distinct C. trachomatis population causing eye infections in Australia. Given that such genotypic information has gone unreported, these findings provide knowledge and a foundation for trachoma-associated C. trachomatis variants circulating in the Northern Territory.