In October 2013, public health authorities were notified of a suspected outbreak of gastroenteritis in students and guests following a catered function at a university residential college. A ...retrospective cohort study was undertaken to examine whether foods served at the function caused illness. A total of 56 cases of gastroenteritis, including seven laboratory-confirmed cases of Campylobacter jejuni infection, were identified in 235 eligible respondents. Univariate analysis showed a significant association with a chicken liver pâté entrée relative risk (RR) 3·64, 95% confidence interval (CI) 2·03–6·52, P < 0·001, which retained significance after adjustment for confounding via multivariable analysis (adjusted RR 2·80, 95% CI 1·26–6·19, P = 0·01). C. jejuni and C. coli were also isolated in chicken liver pâté recovered from the college's kitchen. Subsequent whole genome multilocus sequence typing (wgMLST) of clinical and food-derived C. jejuni isolates showed three genetically distinct sequence types (STs) comprising ST528, ST535 (both clinically derived) and ST991 (food derived). The study demonstrates the value of utilizing complementary sources of evidence, including genomic data, to support public health investigations. The use of wgMLST highlights the potential for significant C. jejuni diversity in epidemiologically related human and food isolates recovered during outbreaks linked to poultry liver.
Food for human and animal consumption can provide a vehicle for the transfer of pathogenic and antimicrobial‐resistant bacteria into the food chain. We investigated the antimicrobial susceptibility ...of 453 Salmonella isolates collected from raw feed components, equipment and finished feed from 17 commercial feed mills in Australia between 2012 and 2021. Previous studies have found Salmonella prevalence and the diversity of Salmonella serotypes are greatest in the raw feed components. We, therefore, hypothesised that we would find a greater proportion of antimicrobial‐resistant Salmonella isolates in the raw feed components compared to other sample types. We found that of 453 isolates tested, 356 (0.80) were susceptible to all antimicrobials tested, 49 (0.11) were nonsusceptible to streptomycin only and 48 (0.11) were resistant to two or more antimicrobials. Of the 48 antimicrobial‐resistant isolates, 44 were found in feed milling equipment, two in raw feed components and two in finished feed. Statistical analysis, using a logistic regression with random effects model, found that the population‐adjusted mean probability of detecting antimicrobial‐resistant Salmonella isolates from feed milling equipment of 0.39, was larger than the probability of detecting resistant isolates in raw feed components 0.01, (P < 0.001) and in finished feed, 0.11, (P = 0.006). This propensity for antimicrobial‐resistant bacteria to colonise feed milling equipment has not been previously reported. Further studies are required to understand the ecology of antimicrobial‐resistant Salmonella in the feed milling environment.
•Salmonella shedding in farrow-to-finish herds with previous S. 1,4,5,12:i:- isolation.•Mixed Salmonella populations, evidence of S. 1,4,5,12:i:- persistence.•High S. 1,4,5,12:i:- detection among ...terminal stock presents a potential hazard source in food.•Similar S. 1,4,5,12:i:- MLVA profiles between and within herds.•MLVA was discriminatory and stable, supporting use in outbreak strain identification.
The shedding patterns of Salmonella spp. and MLVA profiles of Salmonella enterica subspecies enterica (I) serotype 1,4,5,12:i:- were monitored in a 12-month longitudinal observational study of five pig herds to inform management; provide indications of potential hazard load at slaughter; and assist evaluation of MLVA for use by animal and public health practitioners. Twenty pooled faecal samples, stratified by age group, were collected quarterly. When Salmonella was cultured, multiple colonies were characterized by serotyping and where S. Typhimurium-like serovars were confirmed, isolates were further characterized by phage typing and multiple locus variable number tandem repeat analysis (MLVA). Salmonella was detected in 43% of samples. Salmonella 1,4,5,12:i- was one of several serovars that persisted within the herds and was found among colonies from each production stage. Virtually all Salmonella 1,4,5,12:i:- isolates were phage type 193, but exhibited 12 different, closely-related MLVA profiles. Salmonella 1,4,5,12:i:- diversity within herds was low and MLVA profiles were stable indicating colonization throughout the herds and suggesting each farm had an endemic strain. High prevalence of S. 1,4,5,12:i:- specific shedding among terminal animals indicated high hazard load at slaughter, suggesting that primary production may be an important pathway of S. 1,4,5,12:i:- into the human food chain, this has implications for on-farm management and the application and targeting control measures and further evidence of the need for effective process control procedures to be in place during slaughter and in pork boning rooms. These findings have implications for animal health and food safety risk mitigation and risk management.
This retrospective case series identifies the largest cohort of non‐O1, non‐O139 Vibrio cholerae bacteraemia in an Australian population from 2000 to 2013. We examine the risk factors, epidemiology, ...clinical presentations and mortality of non‐O1, non‐O139 V. cholerae bacteraemia in Victoria and compare them with published cases in the literature. This case series highlights the pathogenic potential of non‐O1, non‐O139 V. cholerae and identifies possible associations with host (underlying chronic liver disease and malignancy) and environmental factors (contaminated water supply and raw seafood). Clinicians should be aware of the morbidity and mortality associated with invasive non‐O1, non‐O139 V. cholerae infections, particularly in immunocompromised patients.
Background. Ciprofloxacin-resistant Campylobacter jejuni isolates obtained from infected patients in Australia have not been detected in studies of isolates from specific geographic areas. The ...Australian government has prohibited the use of fluoroquinolone in food-producing animals. To assess the impact of this policy, we have examined the antimicrobial susceptibility of isolates from 5 Australian states. Methods. We conducted a period-prevalence survey of the susceptibility of C. jejuni isolates to 10 antimicrobial agents. C. jejuni isolates obtained from 585 patients from 5 Australian states (Queensland, South Australia, Tasmania, Victoria, and Western Australia) were identified by means of notifiable disease databases and were systematically selected from September 2001 to August 2002. Results. Among locally acquired infections, only 2% of isolates (range, 0%–8% in different states) were resistant to ciprofloxacin. The locally acquired isolates also exhibited resistance to sulfisoxazole (55%), ampicillin (46%), roxithromycin (38%), tetracycline (7%), nalidixic acid (6%), chloramphenicol (3%), erythromycin (3%), gentamicin (2%), and kanamycin (0.2%). Treatment with antimicrobial agents in the 4 weeks before onset was not associated with ciprofloxacin resistance. Conclusions. The very low level of ciprofloxacin resistance in C. jejuni isolates likely reflects the success of Australia's policy of restricting use of fluoroquinolones in food-producing animals.
Multilocus sequence typing (MLST) was used to examine the diversity and population structure of Campylobacter jejuni isolates associated with sporadic cases of gastroenteritis in Australia, and to ...compare these isolates with those from elsewhere. A total of 153 Camp. jejuni isolates were genotyped. Forty sequence types (STs) were found, 19 of which were previously undescribed and 21 identified in other countries. The 19 newly described STs accounted for 43% of isolates, 16 of which were assigned to known clonal complexes. Eighty-eight percent of isolates were assigned to a total of 15 clonal complexes. Of these, four clonal complexes accounted for 60% of isolates. Three STs accounted for nearly 40% of all isolates and appeared to be endemic, while 21 STs were represented by more than one isolate. Seven infections were acquired during international travel, and the associated isolates all had different STs, three of which were exclusive to the travel-acquired cases. Comparison of serotypes among isolates from clonal complexes revealed further diversity. Eight serotypes were identified among isolates from more than one clonal complex, while isolates from six clonal complexes displayed serotypes not previously associated with those clonal complexes. Multilocus sequence typing is a useful tool for the discrimination of subtypes and examination of the population structure of Camp. jejuni associated with sporadic infections. This study highlights the genotypic diversity of Camp. jejuni in Australia, demonstrating that STs causing disease have both a global and a local distribution evident from the typing of domestically and internationally acquired Camp. jejuni isolates.
Abstract
This retrospective case series identifies the largest cohort of non‐
O
1, non‐
O
139
V
ibrio cholerae
bacteraemia in an
A
ustralian population from 2000 to 2013. We examine the risk factors, ...epidemiology, clinical presentations and mortality of non‐
O
1, non‐
O
139
V
. cholerae
bacteraemia in
V
ictoria and compare them with published cases in the literature. This case series highlights the pathogenic potential of non‐
O
1, non‐
O
139
V
. cholerae
and identifies possible associations with host (underlying chronic liver disease and malignancy) and environmental factors (contaminated water supply and raw seafood). Clinicians should be aware of the morbidity and mortality associated with invasive non‐
O
1, non‐
O
139
V
. cholerae
infections, particularly in immunocompromised patients.
1 International Centre for Diarrhoeal Diseases Research, Bangladesh (ICDDR,B) Dhaka, Bangladesh
2 Public Health Microbiology, Queensland Health Scientific Services, Coopers Plains, Queensland, ...Australia
3 Institute of Environmental Science and Research Limited (ESR), Kenepuru Science Centre, Poriru, New Zealand
4 Microbiological Diagnostic Unit Public Health Laboratory (MDUPHL), Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Victoria, Australia
5 World Health Organization (WHO), South Pacific Office, Suva, Fiji
6 Fiji Centre for Communicable Disease Control, Mataika House, Suva, Fiji
7 National Centre for Epidemiology and Population Health, ANU College of Medicine and Health Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
Correspondence Hassan Vally Hassan.Vally{at}anu.edu.au
Received 22 May 2006
Accepted 7 July 2006
Five strains of Vibrio cholerae O1, one each from an Australian and a New Zealand tourist with gastrointestinal illness returning from an island resort in Fiji and the remaining three from water sources located in the same resort, were extensively characterized. Conventional phenotypic traits that are used for biotyping of O1 V. cholerae categorized all five strains as belonging to the El Tor biotype. Genetic screening of 11 regions that are associated with virulence in V. cholerae showed variable results. The absence of genes comprising Vibrio seventh pandemic island-I (VSP-I) and VSP-II in all the strains indicated that these strains were very similar to the pre-seventh pandemic V. cholerae O1 El Tor strains. The ctxAB genes were absent in all strains whereas orfU and zot were present in four strains, indicating that the strains were non-toxigenic. Four strains carried a truncated CTX prophage. Although epidemiological and molecular studies suggested that these strains did not cause cholera amongst tourists at the resort, their similarity to pre-seventh pandemic strains, their prior association with gastrointestinal illness and their presence in the island resort setting warrant more attention.
Aims:Multilocus sequence typing (MLST) was used to examine the diversity and population structure of Campylobacter jejuni isolates associated with sporadic cases of gastroenteritis in Australia, and ...to compare these isolates with those from elsewhere. Methods and Results:A total of 153 Camp. jejuni isolates were genotyped. Forty sequence types (STs) were found, 19 of which were previously undescribed and 21 identified in other countries. The 19 newly described STs accounted for 43% of isolates, 16 of which were assigned to known clonal complexes. Eighty-eight percent of isolates were assigned to a total of 15 clonal complexes. Of these, four clonal complexes accounted for 60% of isolates. Three STs accounted for nearly 40% of all isolates and appeared to be endemic, while 21 STs were represented by more than one isolate. Seven infections were acquired during international travel, and the associated isolates all had different STs, three of which were exclusive to the travel-acquired cases. Comparison of serotypes among isolates from clonal complexes revealed further diversity. Eight serotypes were identified among isolates from more than one clonal complex, while isolates from six clonal complexes displayed serotypes not previously associated with those clonal complexes. Conclusions:Multilocus sequence typing is a useful tool for the discrimination of subtypes and examination of the population structure of Camp. jejuni associated with sporadic infections. Significance and Impact of the Study:This study highlights the genotypic diversity of Camp. jejuni in Australia, demonstrating that STs causing disease have both a global and a local distribution evident from the typing of domestically and internationally acquired Camp. jejuni isolates.
Campylobacter is a common cause of bacterial gastroenteritis in Australia. Antibiotic resistance among Campylobacter is an emerging problem in Europe and the United States of America. Monitoring may ...detect emerging resistance. Since there is no epidemiologically validated subtyping system for Campylobacter, antimicrobial resistance patterns may prove useful as an epidemiological marker. Campylobacter isolates from residents of the Hunter region were differentiated by PCR into two categories: C. jejuni and non-C. jejuni. Minimal inhibitory concentrations (MIC) were determined for 10 antibiotics using the National Committee for Clinical Laboratory Standards (NCCLS) agar dilution methodology. Risk factor information including travel history were obtained as part of a case-control study by conducting telephone interviews with infected individuals. Sixty-four per cent, 3.4 per cent, 3.4 per cent and 11.2 per cent of C. jejuni isolates were resistant to ampicillin (at MIC > 8 mg/L), erythromycin (> 8 mg/L), nalidixic acid (> 32 mg/L) and tetracycline (> 8 mg/L), respectively. A diverse pattern of antibiotic resistance ('resistotypes') was detected with some change occurring over time. Several possible clusters of Campylobacter infections were identified based on resistotype. Of seven infections acquired during overseas travel, 57 per cent (4/7) were resistant to more than one antibiotic class compared to 10 per cent (14/144) of locally-acquired isolates (p=0.004, Fisher exact). The potential usefulness of resistotyping as an epidemiological marker is worthy of further exploration.
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