Multi-drug resistant Salmonella Java infections acquired from tropical fish aquariums, Australia, 2003-04.

Antibiotic resistant Salmonella infections are rare in Australia. We investigated an increase in multidrug resistant Salmonella Paratyphi B biovar Java (S. Java) infections in Australia during 2003-04. Eighty-two per cent (18/22) of S. Java cases enrolled into the study reported that they had been in contact with aquariums housing fish during their incubation period. Seventy-two per cent (13/18) of cases were infected with strains that were resistant to ApSmTcCmSuSp (ampicillin, streptomycin, tetracycline, chloramphenicol, sulfonamides, spectinomycin). Case households commonly reported high risk behaviours, such as cleaning aquaria in sinks. Sixty-one per cent (11/18) of cases reported that fish in their aquarium had been sick or died in the week prior to their illness, and S. Java was isolated from the water or gravel of 5 cases. These antibiotic strains are being spread internationally and may become endemic in countries importing tropical fish or result in transfer of resistance to other more common Salmonella serotypes.

An outbreak of Salmonella Typhimurium phage type 64 gastroenteritis linked to catered luncheons in Adelaide, South Australia, June 2005.

Salmonella sp. are important causes of foodborne illness, with restaurants and catered functions being commonly reported settings for outbreaks. In June 2005 an investigation commenced following reports of gastrointestinal illness in attendees at luncheons catered by an Adelaide café, as well as persons eating at the café itself. The investigation sought to determine the existence of an outbreak, identify a source and method of transmission and implement public health measures to prevent further cases. Lists of luncheon attendees were obtained from function organisers. A retrospective cohort study was commenced using a structured questionnaire developed from the café's menu listings. A suspected case was defined as a person developing two or more gastrointestinal symptoms after attending a luncheon catered by the café. A case series investigation was used for café diners. Of the 102 respondents, 61 (60%) met the case definition with 32 subsequently confirmed as Salmonella Typhimurium phage type 64 (STM 64) infections. Of the 61 cases, 59 (96%) reported eating a bread roll. STM 64 was detected in raw defrosted chicken recovered from the café's kitchen. This suggested cross-contamination from the chicken to one or more ingredients common to the bread rolls was the route of infection. To prevent further cases, perishable goods were discarded, the café was closed, the premises cleaned, then restrictions were placed on the types of foods served. This investigation's findings highlight the importance of safe food handling and hand hygiene in commercial food preparation.

A multi-jurisdiction outbreak of Salmonella Typhimurium phage type 135 associated with purchasing chicken meat from a supermarket chain.

A multi-jurisdiction case control study was conducted after an increase of Salmonella Typhimurium phage type 135 notifications (a local designated subgroup) was observed throughout Australia. Hypothesis generating interviews conducted in three jurisdictions identified consumption of chicken, eggs, beef and bagged carrots as common among cases and that a high proportion of cases (> 80%) reported purchasing their groceries from a particular supermarket chain (Supermarket A). We conducted a case control study to test whether S. Typhimurium 135 infections were associated with these food items and the purchasing of these products from Supermarket A. The study comprised 61 cases and 173 controls. Cases were younger than controls (p = 0.003) and their distribution by jurisdiction was also significantly different (p < 0.001). In multivariate analysis, cases had significantly higher odds of having eaten chicken purchased from Supermarket A (OR = 3.2, 95% CI 1.2,9.0) or having eaten chicken from a fast food outlet (OR = 2.8, 95% CI 1.0,7.7) compared to controls. Two positive S. Typhimurium 135 results were obtained through a chicken sampling survey conducted at four Supermarket A stores in Victoria. The results of this study were presented to industry and retail representatives, which facilitated better communication between these groups.

Ribotyping of Salmonella enterica serovar Typhi isolates from Papua New Guinea over the period 1977 to 1996.

The prevalence of typhoid in the Papua New Guinea (PNG) highlands region increased rapidly in the mid-1980s, and now remains endemic. In this study ribotyping has been used to examine the number and types of Salmonella enterica serovar Typhi strains present during the 1977-1996 period. The ribotyping banding pattern results were based on Cla I and Eco RV digests. The 57 PNG isolates were divided into 11 different ribotypes. Comparison of ribotypes using coefficient of similarity values revealed a diverse group of ribotypes. Several strains appear to be endemic in PNG For instance, ribotypes 1, 2 and 3 were most commonly found among PNG isolates and isolates with these ribotypes have been cultured over a period of at least 11 years (1985-1996). Ribotype 3 was also observed in isolates from Malaysia and Thailand. Also found in PNG were ribotypes 4, 5, 6, 7, 8, 9, 16 and 17. The ribotyping suggests that serovar Typhi strains present in PNG include unique strains of serovar Typhi and also strains that are common to other countries.

Surveillance of Shiga toxigenic Escherichia coli in Australia.

All Australian States and Territories have low rates (< or = 0.32 cases per 100,000 population) of notification for Shiga toxin-producing Escherichia coli (STEC), except for South Australia where the rates are ten-fold higher at 2.58 cases per 100,000 population. To explore possible reasons for the variation in rates we surveyed public health reference laboratories to determine the methods used and number of specimens tested for these organisms. Only five of eight jurisdictions routinely conducted testing for STEC, and polymerase chain based tests were most common. Culture was also common and in one jurisdiction that tests specimens with culture, approximately 1.2 per cent of specimens were positive. The notification rates for different jurisdictions reflected the number of specimens tested, with jurisdiction testing < or = 500 specimens having rates < or = 0.32 cases per 100,000 population. The use of culture as a test method may also influence notification rates. Public health agencies must consider the number of specimens tested in interpreting surveillance data.