Campylobacter Incidence Research Articles

Epidemiology and Antimicrobial Resistance of Campylobacter Infections in the United States, 2005-2018.

Campylobacter is the most common cause of bacterial diarrhea in the United States; resistance to macrolides and fluoroquinolones limits treatment options. We examined the epidemiology of US Campylobacter infections and changes in resistance over time. The Foodborne Diseases Active Surveillance Network receives information on laboratory-confirmed Campylobacter cases from 10 US sites, and the National Antimicrobial Resistance Monitoring System receives a subset of isolates from these cases for antimicrobial susceptibility testing. We estimated trends in incidence of Campylobacter infection, adjusting for sex, age, and surveillance changes attributable to culture-independent diagnostic tests. We compared percentages of isolates resistant to erythromycin or ciprofloxacin during 2005-2016 with 2017-2018 and used multivariable logistic regression to examine the association of international travel with resistance. Adjusted Campylobacter incidence remained stable or decreased for all groups analyzed since 2012. Among 2449 linked records in 2017-2018, the median patient age was 40.2 years (interquartile range, 21.6-57.8 years), 54.8% of patients were male, 17.2% were hospitalized, and 0.2% died. The percentage of resistant infections increased from 24.5% in 2005-2016 to 29.7% in 2017-2018 for ciprofloxacin (P < .001) and from 2.6% to 3.3% for erythromycin (P = .04). Persons with recent international travel had higher odds than nontravelers of having isolates resistant to ciprofloxacin (adjusted odds ratio [aOR] varied from 1.7 to 10.6 by race/ethnicity) and erythromycin (aOR = 1.7; 95% confidence interval, 1.3-2.1). Campylobacter incidence has remained stable or decreased, whereas resistance to antimicrobials recommended for treatment has increased. Recent international travel increased the risk of resistance.

Enhanced Biosecurity Measures May Contribute to the Reduction of Campylobacter Incidence in Slaughterhouses

Enhanced Biosecurity Measures May Contribute to the Reduction of Campylobacter Incidence in Slaughterhouses

Seasonality and the effects of weather on Campylobacter infections

BackgroundCampylobacteriosis is a major public health concern. The weather factors that influence spatial and seasonal distributions are not fully understood.MethodsTo investigate the impacts of temperature and rainfall on Campylobacter infections in England and Wales, cases of Campylobacter were linked to local temperature and rainfall at laboratory postcodes in the 30 days before the specimen date. Methods for investigation included a comparative conditional incidence, wavelet, clustering, and time series analyses.ResultsThe increase of Campylobacter infections in the late spring was significantly linked to temperature two weeks before, with an increase in conditional incidence of 0.175 cases per 100,000 per week for weeks 17 to 24; the relationship to temperature was not linear. Generalized structural time series model revealed that changes in temperature accounted for 33.3% of the expected cases of Campylobacteriosis, with an indication of the direction and relevant temperature range. Wavelet analysis showed a strong annual cycle with additional harmonics at four and six months. Cluster analysis showed three clusters of seasonality with geographic similarities representing metropolitan, rural, and other areas.ConclusionsThe association of Campylobacteriosis with temperature is likely to be indirect. High-resolution spatial temporal linkage of weather parameters and cases is important in improving weather associations with infectious diseases. The primary driver of Campylobacter incidence remains to be determined; other avenues, such as insect contamination of chicken flocks through poor biosecurity should be explored.

Statistical adjustment of culture-independent diagnostic tests for trend analysis in the Foodborne Diseases Active Surveillance Network (FoodNet), USA.

Culture-independent diagnostic tests (CIDTs) are increasingly used to diagnose Campylobacter infection in the Foodborne Diseases Active Surveillance Network (FoodNet). Because CIDTs have different performance characteristics compared with culture, which has been used historically and is still used to diagnose campylobacteriosis, adjustment of cases diagnosed by CIDT is needed to compare with culture-confirmed cases for monitoring incidence trends. We identified the necessary parameters for CIDT adjustment using culture as the gold standard, and derived formulas to calculate positive predictive values (PPVs). We conducted a literature review and meta-analysis to examine the variability in CIDT performance and Campylobacter prevalence applicable to FoodNet sites. We then developed a Monte Carlo method to estimate test-type and site-specific PPVs with their associated uncertainties. The uncertainty in our estimated PPVs was largely derived from uncertainty about the specificity of CIDTs and low prevalence of Campylobacter in tested samples. Stable CIDT-adjusted incidences of Campylobacter cases from 2012 to 2015 were observed compared with a decline in culture-confirmed incidence. We highlight the lack of data on the total numbers of tested samples as one of main limitations for CIDT adjustment. Our results demonstrate the importance of adjusting CIDTs for understanding trends in Campylobacter incidence in FoodNet.

Factors associated with increasing campylobacteriosis incidence in Michigan, 2004-2013.

This study was conducted to examine the incidence trend of campylobacteriosis in Michigan over a 10-year period and to investigate risk factors and clinical outcomes associated with infection. Campylobacter case data from 2004 to 2013 was obtained from the Michigan Disease Surveillance System. We conducted statistical and spatial analyses to examine trends and identify factors linked to campylobacteriosis as well as ecological associations using animal density data from the National Agricultural Statistics Service. An increasing trend of Campylobacter incidence and hospitalization was observed, which was linked to specific age groups and rural residence. Cases reporting ruminant contact and well water as the primary drinking source had a higher risk of campylobacteriosis, while higher cattle density was associated with an increased risk at the county level. Additional studies are needed to identify age-specific risk factors and examine prevalence and transmission dynamics in ruminants and the environment to aid in the development of more effective preventive strategies.

Time-series analysis of Campylobacter incidence in Switzerland.

Campylobacteriosis has been the most common food-associated notifiable infectious disease in Switzerland since 1995. Contact with and ingestion of raw or undercooked broilers are considered the dominant risk factors for infection. In this study, we investigated the temporal relationship between the disease incidence in humans and the prevalence of Campylobacter in broilers in Switzerland from 2008 to 2012. We use a time-series approach to describe the pattern of the disease by incorporating seasonal effects and autocorrelation. The analysis shows that prevalence of Campylobacter in broilers, with a 2-week lag, has a significant impact on disease incidence in humans. Therefore Campylobacter cases in humans can be partly explained by contagion through broiler meat. We also found a strong autoregressive effect in human illness, and a significant increase of illness during Christmas and New Year's holidays. In a final analysis, we corrected for the sampling error of prevalence in broilers and the results gave similar conclusions.

Quality and safety of broiler meat in various chilling systems

Chilling is a critical step in poultry processing to attain high-quality meat and to meet the USDA-Food Safety and Inspection Service temperature standards. This study was conducted to determine the effects of commercially available chilling systems on quality and safety of broiler meat. A total of 300 carcasses in 2 replications were randomly selected from a commercial processor and subjected to 3 systems: immersion chill (IC), air chill (AC), and combi in-line air chill (CIAC). Incidence of Salmonella and Campylobacter were determined on pre- and postchilled carcasses. Quality of the meat was evaluated by carcass yield, drip loss, cook loss, texture, moisture content, sensory qualities, and color (L*, a*, and b*) of boneless skinless breast fillets and skin-on drums. Shelf life of whole carcasses, breast fillets, and drums was also determined. The IC resulted in the most reduction of Salmonella (39.7%) and Campylobacter (43%) incidence due to the washing effect and presence of chlorine in the chilled water. There was no significant difference in shelf-life when comparing the chilling methods. The IC had the highest (P < 0.05) carcass yield (6.5%), followed by CIAC (+1.98.0%) and then AC (-1.10%). Drip loss, cook loss, and moisture content of breast fillets were not significantly different for all the chilling systems, but higher L* value was observed for breast fillets at 24 h postmortem treated with IC and CIAC. However, IC exhibited the lightest color and AC was darkest in the drum samples. Shear force of breast meat was significantly more tender for AC and CIAC. There were no differences in the sensory qualities of breast fillets and drums among the 3 chilling systems.

Trends in Campylobacter incidence in broilers and humans in six European countries, 1997–2007

The objective of this study was to examine incidences of Campylobacter in broilers and humans, and to describe seasonal variation and long-term trends by comparing longitudinal surveillance data in six Northern European countries (Denmark, Finland, Iceland, Norway, Sweden and the Netherlands). Due to high degree of seasonality and autocorrelation, seasonally adjusted (de-seasonalized) and trend adjusted data (de-trended) were used for comparing incidences within and between the six countries. De-seasonalized time series were obtained by fitting the incidence time series to mean monthly temperature and then removing this effect from the data. Long-term trends were fitted to the de-seasonalized time series. The incidence of Campylobacter colonization in broiler flocks and incidence of campylobacteriosis in humans showed a concordant seasonality for all the countries. There was a strong association between the incidence in both broilers and humans in a given month and the mean temperature of the northern hemisphere in the same month, as well as the preceding month, as shown by the cross-correlations and the chosen Generalized Additive Model. Denmark and Sweden showed a steadily decreasing trend for Campylobacter in broilers and human campylobacteriosis in the period 2001–2007. In Iceland, there was a decreasing trend for campylobacteriosis in humans from 1999 to 2007, whilst the broiler trend for Campylobacter was stable from 2001 to 2004, then falling thereafter. In Norway, the human campylobacteriosis trend showed a steady increase throughout the period. On the other hand, the Norwegian broiler trend for Campylobacter showed a decrease from 2001 until 2004, but was thereafter stable. There was no significant decrease or increase in incidence for human campylobacteriosis in the Netherlands, and the trend for Campylobacter in broilers was close to stable. The seasonality seen in broiler and human closely follows the temperature, and was probably caused, at least partly, by temperature related factors.

Spatio-temporal cluster analysis of the incidence of Campylobacter cases and patients with general diarrhea in a Danish county, 1995–2004

Campylobacter infections are the main cause of bacterial gastroenteritis in Denmark. While primarily foodborne, Campylobacter infections are also to some degree acquired through other sources which may include contact with animals or the environment, locally contaminated drinking water and more. We analyzed Campylobacter cases for clustering in space and time for the large Danish island of Funen in the period 1995–2003, under the assumption that infections caused by 'environmental' factors may show persistent clustering while foodborne infections will occur randomly in space. Input data were geo-coded datasets of the addresses of laboratory-confirmed Campylobacter cases and of the background population of Funen County. The dataset had a spatial extent of 4.900 km2. Data were aggregated into units of analysis (so-called features) of 5 km by 5 km times 1 year, and the Campylobacter incidence calculated. We used a modified form of local Moran's I to test if features with similar incidence rates occurred next to each other in space and time, and compared the observed clusters with simulated clusters. Because clusters may be caused by a high tendency among local GPs to submit stool samples, we also analyzed a dataset of all submitted stool samples for comparison. The results showed a significant persisting clustering of Campylobacter incidence rates in the Western part of Funen. Results were visualized using the Netlogo software. The underlying causes of the observed clustering are not known and will require further examination, but may be partially explained by an increased rate of stool samples submissions by physicians in the area. We hope, by this approach, to have developed a tool which will allow for analyses of geographical clusters which may in turn form a basis for further epidemiological examinations to cast light on the sources of infection.

Campylobacter Incidence Drops, Yet Is High in Young Children

Campylobacter Incidence Drops, Yet Is High in Young Children

Risk factors and likelihood of Campylobacter colonization in broiler flocks

Campylobacter was investigated in cecal droppings, feces, and cloacal swabs of 22 flocks of 3 to 5 week-old broilers. Risk factors and the likelihood of the presence of this agent in these flocks were determined. Management practices, such as cleaning and disinfection, feeding, drinkers, and litter treatments, were assessed. Results were evaluated using Odds Ratio (OR) test, and their significance was tested by Fisher’s test (p<0.05). A Campylobacter prevalence of 81.8% was found in the broiler flocks (18/22), and within positive flocks, it varied between 85 and 100%. Campylobacter incidence among sample types was homogenous, being 81.8% in cecal droppings, 80.9% in feces, and 80.4% in cloacal swabs (230). Flocks fed by automatic feeding systems presented higher incidence of Campylobacter as compared to those fed by tube feeders. Litter was reused in 63.6% of the farm, and, despite the lack of statistical significance, there was higher likelihood of Campylobacter incidence when litter was reused. Foot bath was not used in 45.5% of the flocks, whereas the use of foot bath associated to deficient lime management increased the number of positive flocks, although with no statiscal significance. The evaluated parameters were not significantly associated with Campylobacter colonization in the assessed broiler flocks.

Spatial analysis of campylobacter infection in the Canadian province of Manitoba.

BackgroundThe study describes population level variations in campylobacter incidence within the Canadian province of Manitoba, and the relationship to sociodemographic and landscape related characteristics. Using data derived from the Manitoba Health Public Health Branch communicable disease surveillance database, the study applied a number of spatial and ecological techniques to visualize, explore and model campylobacter incidence for the years 1996 to 2004. Analytical techniques used in the study included spatial smoothing, the spatial scan statistic, the Gini coefficient, and Poisson regression analysis.ResultsThe study demonstrated marked and statistically significant geographic variability in the rates of campylobacter incidence in Manitoba.. The incidence of campylobacter was observed to be significantly higher in populations living in rural and agricultural areas of the province, with the highest rates occurring in populations living in proximity to high densities of farm animals (cows, pigs, chickens). The study also observed that the age specific pattern of campylobacter incidence in rural Manitoba was very different than the urban pattern, with the incidence rate in the 0–4 year age group seven times higher in rural Manitoba than in the City of Winnipeg.ConclusionThe study demonstrates the value of a deploying a diverse set of spatial techniques to better understand the dynamics of an enteric disease such as campylobacter infection. The study concludes that there may be three distinct mechanisms for the transmission of campylobacter in Manitoba which are operating simultaneously. These include broad population exposure to a centralized food system endemically infected with the campylobacter organism, exposure to local level factors such as farm animals or contaminated water, and exposure to campylobacter infection through foreign travel.

Occurrence of Campylobacter and Listeria monocytogenes in a Poultry Processing Plant

The occurrence of Campylobacter and Listeria monocytogenes was studied in 645 samples from surfaces, water, and poultry products (chicken carcasses, chicken parts, viscera, and spoils) in a poultry processing plant in southern Brazil. The automated mini-VIDAS system was used to detect the presence of Campylobacter and L. monocytogenes on the samples. The positive samples were confirmed by conventional methods. Campylobacter and L. monocytogenes were found in 16.6 and 35.6% of the analyzed samples, respectively. The sampling points with the highest Campylobacter incidence were intestine (63.3%, 19 of 30 samples), gallbladder (46.7%, 14 of 30), carcasses before evisceration (33.33%, 10 of 30), and carcasses after plucking (30%, 9 of 30). For L. monocytogenes, the majority of positive samples were from frozen breast (100%, 15 of 15 samples), frozen wing (93.3%, 14 of 15), fresh breast (83.3%, 25 of 30), fresh wing (80%, 24 of 30), skin of breast and leg (76.7%, 23 of 30), frozen leg (60%, 9 of 15), and fresh leg (50%, 15 of 30).

Effect of Fecal Contamination and Cross-Contamination on Numbers of Coliform, Escherichia coli, Campylobacter, and Salmonella on Immersion-Chilled Broiler Carcasses

The effect of prechill fecal contamination on numbers of bacteria on immersion-chilled carcasses was tested in each of three replicate trials. For each trial, 16 eviscerated broiler carcasses were split into 32 halves and assigned to one of two groups. Cecal contents (0.1g inoculated with Campylobacter and nalidixic acid–resistant Salmonella) were applied to each of eight halves in one group (direct contamination) that were placed into one paddle chiller (contaminated), whereas the other paired halves were placed into another chiller (control). From the second group of eight split birds, one of each paired half was placed in the contaminated chiller (to determine cross-contamination) and the other half was placed in the control chiller. Postchill carcass halves were sampled by a 1-min rinse in sterile water, which was collected and cultured. Bacterial counts were reported as log CFU per milliliter of rinsate. There were no significant statistical differences (paired t test, P < 0.05) from direct contamination for coliforms (mean 3.0 log CFU) and Escherichia coli (mean 2.7 log CFU), although Campylobacter numbers significantly increased from control values because of direct contamination (1.5 versus 2.1 log CFU), and the incidence increased from 79 to 100%. There was no significant effect of cross-contamination on coliform (mean 2.9 log CFU) or E. coli (mean 2.6 log CFU) numbers. Nevertheless, Campylobacter levels were significantly higher after exposure to cross-contamination (1.6 versus 2.0 log CFU), and the incidence of this bacterium increased from 75 to 100%. Salmonella-positive halves increased from 0 to 42% postchill because of direct contamination and from 0 to 25% as a result of cross-contamination after chilling. Water samples and surface swabs taken postchill from the contaminated chiller were higher for Campylobacter than those taken from the control chiller. Immersion chilling equilibrated bacterial numbers between contaminated and control halves subjected to either direct contamination or cross-contamination for coliforms and E. coli. Campylobacter numbers, Campylobacter incidence, and Salmonella incidence increased because of both direct contamination and cross-contamination in the chiller. Postchill E. coli numbers did not indicate which carcass halves were contaminated with feces before chilling.

Prevalences and transmission routes of Campylobacter spp. strains within multiple pig farms

In this work, faecal samples were collected from 15 pig farms to determine the Campylobacter prevalences at different times during the rearing period and to visualize the exchange of strains among the pig population by genotyping specific isolates. All isolated strains were identified as C. coli. Whereas no Campylobacter were detectable in the faeces of piglets at the day of birth, the Campylobacter incidence rose within days to 32.8%. After transfer to the nursery unit the prevalence increased to 56.6%. Approximately two-thirds of the pigs remained C. coli shedders in the fattening unit. In contrast to most farms, one farm expressed a very low Campylobacter incidence during the whole rearing period. Amplified fragment length polymorphism (AFLP) analysis was performed on all C. coli isolates of one farm. Clonal strains were identified from the brood sows and their offsprings or neighbouring piglets. After moving to the nursery unit, new genotypes appeared in that pig group but the original C. coli strains largely remained within that group. C. coli genotypes, identified during the fattening period, replaced the previously isolated genotypes. Transportation to the abattoir had no significant influence on the shedding rate of C. coli. The detection rate before transportation was 79.1% and decreased slightly to 78.2% (n=330). Additionally, eleven of 1474 environmental samples from different sources of the pig farms were positive for C. coli. This study demonstrates the importance of pigs as a reservoir for C. coli. Maternal C. coli strains are the primary source of infection but non-related genotypes from different sources appear during the rearing period and these latter strains constitute largely the final C. coli flora.

Association between environmental risk factors and campylobacter infections in Sweden.

Campylobacter sp. is the most common cause of acute bacterial gastroenteritis in Sweden and the incidence has been increasing. Case-control studies to identify risk factors have been conducted in several countries, but much remains unexplained. The geographical distribution of campylobacter infections varies substantially, and many environmental factors may influence the observed pattern. Geographical Information Systems (GIS) offer an opportunity to use routinely available surveillance data to explore associations between potential environmental risk factors showing a geographical pattern and disease incidence, complementing traditional approaches for investigating risk factors for disease. We investigated associations between campylobacter incidence and environmental factors related to water and livestock in Sweden. Poisson regression was used to estimate the strength of the associations. Positive associations were found between campylobacter incidence and average water-pipe length per person, ruminant density, and a negative association with the percentage of the population receiving water from a public water supply. This indicates that drinking water and contamination from livestock may be important factors in explaining sporadic human campylobacteriosis in Sweden, and that contamination occurring in the water distribution system might be more important than previously considered.

Quantitative risk assessment of human campylobacteriosis associated with thermophilic Campylobacter species in chickens

A quantitative risk assessment comprising the elements hazard identification, hazard characterization, exposure assessment, and risk characterization has been prepared to assess the effect of different mitigation strategies on the number of human cases in Denmark associated with thermophilic Campylobacter spp. in chickens. To estimate the human exposure to Campylobacter from a chicken meal and the number of human cases associated with this exposure, a mathematical risk model was developed. The model details the spread and transfer of Campylobacter in chickens from slaughter to consumption and the relationship between ingested dose and the probability of developing campylobacteriosis. Human exposure was estimated in two successive mathematical modules. Module 1 addresses changes in prevalence and numbers of Campylobacter on chicken carcasses throughout the processing steps of a slaughterhouse. Module 2 covers the transfer of Campylobacter during food handling in private kitchens. The age and sex of consumers were included in this module to introduce variable hygiene levels during food preparation and variable sizes and compositions of meals. Finally, the outcome of the exposure assessment modules was integrated with a Beta–Poisson dose–response model to provide a risk estimate. Simulations designed to predict the effect of different mitigation strategies showed that the incidence of campylobacteriosis associated with consumption of chicken meals could be reduced 30 times by introducing a 2 log reduction of the number of Campylobacter on the chicken carcasses. To obtain a similar reduction of the incidence, the flock prevalence should be reduced approximately 30 times or the kitchen hygiene improved approximately 30 times. Cross-contamination from positive to negative flocks during slaughter had almost no effect on the human Campylobacter incidence, which indicates that implementation of logistic slaughter will only have a minor influence on the risk. Finally, the simulations showed that people in the age of 18–29 years had the highest risk of developing campylobacteriosis.

Practical intervention strategies for Campylobacter

Campylobacter organisms arc present in the environment of the farm and it is accepted that the chance of infection transferring to chickens is very high. Sources of infection may include any of the standard requirements for poultry such as feed, water and litter. Any form of human intervention as a result of routine animal husbandry requirements may also introduce infection. It has been shown that on some farms it is possible to delay infection by various improvements to bio-security arrangements. The use of dedicated wellington boots for each poultry house and the regular use of foot dips were found to be important factors. The daily use of water sanitiser was also important in delaying the onset of infection. The efficiency of cleaning and disinfection and the construction of the buildings were less significant factors. If flocks were thinned, which involves entry by catching crews and equipment, the risk of infection was dramatically increased. After 42 d of age, the likelihood of infection was also much greater. The effectiveness of these intervention procedures applied in one integrated poultry company are described. Generally, it was felt that even the most stringent bio-security measures applied conscientiously would not be able to prevent infection occurring. Once infection has entered the house, all birds become Campylobacter carriers very quickly. A pen trial was set up to investigate this and the results are described.

Campylobacter incidence on a chicken farm and the spread of Campylobacter during the slaughter process

To get a better understanding of the epidemiology of Campylobacter, a chicken farm was studied for 16 weeks with samplings in each flock weekly from input until the flock became colonized with Campylobacter or slaughtered. Samples were taken from fresh droppings and from drinkers during the rearing period, as well as from the environment in empty houses. The spread of Campylobacter during the slaughter process was also surveyed. No Campylobacter was found in samples from newly-hatched or one-week-old chickens or their drinkers. All flocks but one were colonized at two to five weeks of age. All Campylobacter isolates belonged to the same sero- and biotype; C. jejuni Penner 2. The spread of Campylobacter in the flock was rapid and usually all samples were positive once colonization had been proven. C. jejuni was isolated from flies in ante-rooms as well as from air in chicken units in houses with positive chicken flocks. Samples were taken at slaughter when some of the Campylobacter positive flocks from the farm were slaughtered. Campylobacter were isolated from all sampled equipment along the processing line, from the chicken transport crates to the chillers, as well as from the air.

A demographic survey of campylobacter, salmonella and shigella infections in England. A Public Health Laboratory Service Survey.

Five laboratories serving a population of 1.5 million participated in a 2-year survey of campylobacter, salmonella and shigella infections in patients suffering from gastrointestinal symptoms. In total, 33,857 faecal specimens were examined of which 5.5% yielded campylobacters, 3.4% salmonellas and 0.8% shigellas; incidence of infection (per 100,000 population per year) was 58, 38 and 9 respectively. Peak incidences occurred at different ages for each organism: campylobacter, 1-4 years (183); salmonella, less than 1 year (181); shigella, 1-4 years (17). There was a secondary peak in campylobacter incidence in patients aged 15-24 years (87), which was not seen with salmonella or shigella infections. By recording the age and sex of all patients submitting faecal specimens, it was shown that sampling rates were disproportionately high in infants aged less than 1 year (12:1 relative to other ages). Thus the percentage of faecal samples positive in infants--in sharp contrast to incidence values--was the lowest of any age group for all three organisms. By taking the numbers of faecal specimens tested as denominators in this way, the highest campylobacter isolation rates were in young adults, with a notable male predominance in the 15-24 year (1.7:1) and 45-54 year (1.6:1) age groups. This male predominance was accentuated during the summer (2.1:1) when incidence was generally high. The maximum percentage isolation recorded by any laboratory was 32.5% in males aged 15-24 years in June. The reasons for this pattern of campylobacter infection are unknown, but the similarity of the results between laboratories and the regularity of the seasonal fluctuations recorded over the last 6 years indicate that the sources and routes of infection are geographically similar and stable, yet different from those of salmonellosis.