Ingrid Hansson

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.

Salmonella isolated from animals and feed production in Sweden between 1993 and 1997.

AbstractThis paper presents Salmonella data from animals, feedstuffs and feed mills in Sweden between 1993 and 1997. During that period, 555 isolates were recorded from animals, representing 87 serotypes. Of those, 30 serotypes were found in animals in Sweden for the first time. The majority of all isolates from animals were S. Typhimurium (n = 91), followed by S. Dublin (n = 82). There were 115 isolates from cattle, 21 from broilers, 56 from layers and 18 from swine. The majority of these isolates were from outbreaks, although some were isolated at the surveillance at slaughterhouses. The number of isolates from the feed industry was similar to that of the previous 5-year period. Most of those findings were from dust and scrapings from feed mills, in accordance with the HACCP programme in the feed control programme. It can be concluded that the occurrence of Salmonella in animals and in the feed production in Sweden remained favourable during 1993–97.SammanfattningSalmonella isolerad från djur och foder i Sverige under perioden 1993-1997. Denna studie ingår i en serie som presenterar Salmonella- isolat från djur och foder i Sverige, med början 1949. Under perioden 1993 till 1997 rapporterades 555 isolat från djur. Under perioden 1988-92 isolerades 598 isolat från djur. Jämförelser av resultat mellan de olika studierna måste göras med försiktighet eftersom provtagning och övervakning kan ha varierat mellan de olika studieperioderna. Antalet isolat från nötkreatur var 115, medan 21 var från slaktkycklingar, 56 från värphöns, och 18 från svin. För första gången härrörde majoriteten av isolat från annat djurslag (165 isolat från reptiler) än nötkreatur. Iden aktuella studien registrerades 87 olika Salmonella- serotyper, vilket är det största antalet som har rapporterats i serien. Trettio av dessa serotyper isolerades från djur i Sverige för första gången. Majoriteten av isolat visade sig tillhöra S. Typhimurium (n=91), följt av S. Dublin (n=82). Antalet isolat från foder (n=749) skilde sig inte väsentligt från den föregående rapporteringsperioden. Majoriteten av de positiva proverna härrörde från prover som insamlades enligt HACCP principer i kontrollprogrammet för foder. Det kan sammanfattas att Salmonella-situationen i Sverige var god under den aktuella studieperioden och tyder på att kontrollprogrammet fungerar tillfredsställande i strävan att hålla hela livsmedelskedjan från jord till bord fri från kontamination.

Within-flock variations of Campylobacter loads in caeca and on carcasses from broilers

The proportions of broiler caeca and carcass rinse samples positive for Campylobacter spp. within broiler flocks were determined. Twenty intact caeca per flock from 27 flocks were analyzed individually. Rinse samples were obtained from 5 to 25 carcasses from 27 other flocks. In total, 540 caecum samples and 445 carcass rinse samples were analyzed. The proportion of positive caeca within flocks ranged from 10 to 100%, and the proportion of positive carcasses ranged from 85 to 100%. The highest and lowest numbers of Campylobacter spp. found in positive caecum samples were 8.6 and 1.7log cfu/g caecal contents, respectively. The number of Campylobacter spp. in the caeca from individual broilers within a flock varied by up to 6.3log cfu/g caecal contents. The highest number found on one carcass was 4.2log cfu/ml carcass rinse sample, and the within-flock variation in Campylobacter spp. was up to 3.2log cfu/ml rinse sample. There was thus great variation in the load of Campylobacter spp. in individual caecum and carcass samples obtained from each positive broiler flock. This large variation in the numbers of Campylobacter spp. carried by individual birds should be considered when only one or a few samples are collected from a flock and the results are used for risk assessments.

Risk factors associated with the presence of Campylobacter-positive broiler flocks in Sweden

Approximately 40% of Swedish broiler producers deliver Campylobacter-negative broilers in 90-100% of their flocks, showing that it is possible to produce Campylobacter-free broilers in Sweden. This study investigated risk factors associated with the presence of Campylobacter-positive flocks at Swedish broiler producers. A total of 37 producers, with 90 broiler houses including 144 compartments, participated in the study. An on-farm interview was performed to collect information on potential risk factors for Campylobacter infection in broilers, with questions about farmcharacteristics such as the environment around the farm and broiler houses, design of the broiler houses and on-farm management practices. Negative binomial regression models were used to assess the statistical significance of risk factors associated with the within-farm number of Campylobacter-positive flocks (the outcome). Campylobacter is transmitted in broiler flocks due to multiple factors and several potential sources, illustrating the complexity of Campylobacter epidemiology in broilers. Factors significantly associated with increased proportion of Campylobacter-positive flocks were the presence of other livestock on the farm, or the presence of cattle, swine, poultry or fur animals within 1km of the farm. Poor or average general tidiness were associated with increased proportion of Campylobacter-positive flocks, but decreased if split slaughter was seldom or never applied or if farm workers changed footwear twice or three times instead of once before entering the broiler house.

Infectious causes for feline upper respiratory tract disease – a case–control study

The aim of this case–control study was to investigate the prevalence of microorganisms in group-living cats with clinical signs of upper respiratory tract disease (URTD), in in-contact cats and in cats in groups without URTD problems. Samples were taken from the ventral conjunctival fornix for analysis of feline herpesvirus-1 (FHV), Mycoplasma felis and Chlamydiaceae using a real-time polymerase chain reaction technique. The oropharynx was sampled for bacteriological culture and viral isolation. Specific infectious agents were identified in 11/20 (55%) of the case households, in 7/20 (35%) of the cats with clinical signs and in 3/20 (15%) of the control households, in 3/40 (7.5%) of the cats. Chlamydiae and M felis were only detected from case households, both from cats with URTD and from in-contact cats. The difference in prevalence between case and control households was statistically significant for M felis (P=0.047). The presence of M felis in cat groups was thus associated with clinical signs of URTD.

Streptococcus devriesei sp nov., from equine teeth

Phenotypic and phylogenetic studies were performed on four unidentified Gram-positive staining, catalase-negative, alpha-hemolytic Streptococcus-like organisms recovered from the teeth of horses. SDS PAGE analysis of whole-cell proteins and comparative 16S rRNA gene sequencing demonstrated the four strains were highly related to each other but that they did not correspond to any recognised species of the genus Streptococcus. Phylogenetic analysis based on 16S rRNA gene sequences showed the unidentified organisms form a hitherto unknown sub-line within the Streptococcus genus, displaying a close affinity with Streptococcus mutans, Streptococcus ferus and related organisms. Sequence divergence values of > 5% with these and other reference streptococcal species however demonstrated the organisms from equine sources represent a novel species. Based on the phenotypic distinctiveness of the new bacterium and molecular chemical and molecular genetic evidence, it is proposed that the unknown species be classified as Streptococcus devriesei sp. nov. The type strain of Streptococcus devriesei is CCUG 47155T (= CIP 107809T).

Identification of nine sequence types of the 16S rRNA genes of Campylobacter jejuni subsp. jejuni isolated from broilers

BackgroundCampylobacter is the most commonly reported bacterial cause of enteritis in humans in the EU Member States and other industrialized countries. One significant source of infection is broilers and consumption of undercooked broiler meat. Campylobacter jejuni is the Campylobacter sp. predominantly found in infected humans and colonized broilers. Sequence analysis of the 16S rRNA gene is very useful for identification of bacteria to genus and species level. The objectives in this study were to determine the degree of intraspecific variation in the 16S rRNA genes of C. jejuni and C. coli and to determine whether the 16S rRNA sequence types correlated with genotypes generated by PFGE analysis of Sma I restricted genomic DNA of the strains.MethodsThe 16S rRNA genes of 45 strains of C. jejuni and two C. coli strains isolated from broilers were sequenced and compared with 16S rRNA sequences retrieved from the Ribosomal Database Project or GenBank. The strains were also genotyped by PFGE after digestion with Sma I.ResultsSequence analyses of the 16S rRNA genes revealed nine sequence types of the Campylobacter strains and the similarities between the different sequence types were in the range 99.6–99.9%. The number of nucleotide substitutions varied between one and six among the nine 16S rRNA sequence types. One of the nine 16S rRNA sequence profiles was common to 12 of the strains from our study and two of these were identified as Campylobacter coli by PCR/REA. The other 10 strains were identified as Campylobacter jejuni. Five of the nine sequence types were also found among the Campylobacter sequences deposited in GenBank. The three 16S rRNA genes in the analysed strains were identical within each individual strain for all 47 strains.ConclusionC. jejuni and C. coli seem to lack polymorphisms in their 16S rRNA gene, but phylogenetic analysis based on 16S rRNA sequences was not always sufficient for differentiation between C. jejuni and C. coli. The strains were grouped in two major clusters according to 16S rRNA, one cluster with only C. jejuni and the other with both C. jejuni and C. coli. Genotyping of the 47 strains by PFGE after digestion with Sma I resulted in 22 subtypes. A potential correlation was found between the Sma I profiles and the 16S rRNA sequences, as a certain Sma I type only appeared in one of the two major phylogenetic groups.

Lactobacillus psittaci sp. nov., isolated from a hyacinth macaw (Anodorhynchus hyacinthinus).

A Gram-positive, non-spore-forming, catalase-negative, facultatively anaerobic coccibacillus to rod-shaped bacterium isolated from a parrot was characterized using phenotypic and molecular taxonomic methods. The unknown bacterium phenotypically resembled lactobacilli and comparative 16S rRNA gene sequencing demonstrated that the organism represents a distinct subline within the Lactobacillus delbrueckii rRNA cluster of the genus. 16S rRNA sequence divergence values of > 6% with recognized Lactobacillus species clearly demonstrated the phylogenetic separateness of the parrot bacterium. On the basis of phylogenetic evidence and the phenotypic distinctiveness of the unknown bacterium, a new species, Lactobacillus psittaci sp. nov., is proposed. The type strain of Lactobacillus psittaci is CCUG 42378T (= CIP 106492T).

Confirmation of a Campylobacteriosis Outbreak Associated with Chicken Liver Pâté Using PFGE and WGS

In May 2012, an outbreak of campylobacteriosis occurred in southern Sweden at a wedding reception affecting 44 persons. A total of 17 cases were notified (13 were culture positive for Campylobacter spp.). Epidemiological investigation suspected chicken liver pâté as the source of infection. The liver pâté had been deliberately undercooked, lightly fried to keep the right texture and mixed with spices. Campylobacter isolates from six cases as well as three Campylobacter isolates from chicken flocks previously raised by the producer delivering the liver were subtyped using pulsed‐field gel electrophoresis and whole‐genome sequencing. Indistinguishable PFGE profiles were identified among five human and one chicken C. jejuni isolates as well among the two C. coli isolates, one from a human case and one from a chicken. WGS supported the PFGE findings; the six C. jejuni isolates belonged to one cluster. All these six isolates were of MLST type ST 50 (ST‐CC 21). This study highlights the importance of a combination of strict biosecurity at the flock‐level as well as adequate cooking of chicken liver to prevent transmission of Campylobacter to humans.

A Prospective Follow-Up Study on Transmission of Campylobacter from Poultry to Abattoir Workers

Contact with poultry or poultry meat is a well-known risk factor for campylobacteriosis, but prospective studies on transmission of Campylobacter from chickens to humans during slaughter are scarce. In this study, we monitored transmission of Campylobacter from slaughtered chicken to originally culture-negative abattoir workers during the peak season of colonized chicken and human Campylobacter infection. Stool samples were obtained from 28 abattoir workers together with data on health status once a month between June and September 2010, with a follow-up sample collected in February 2011. Campylobacter-positive individuals and chicken flocks were identified by culture, and isolates were further characterized using molecular techniques. Campylobacter was isolated from seven asymptomatic individuals. Four of them had been newly employed and had not reported any previous Campylobacter infection. Four human isolates had matching genetic fingerprints with isolates from recently slaughtered chickens. Our results further support the role of chicken as the source of human Campylobacter infection but suggest that asymptomatic Campylobacter infection may occur even in individuals with only limited earlier exposure to Campylobacter.