A temporal study of Salmonella serovars in animals in Alberta between 1990 and 2001

Passive laboratory-based surveillance data from Alberta Agriculture Food and Rural Development were analyzed for common Salmonella serovars, prevalences, trends, and for the presence of temporal clusters. There were 1767 isolates between October 1990 and December 2001 comprising 63 different serovars, including 961 isolates from chickens, 418 from cattle, 108 from pigs, 102 from turkeys, and 178 from all other species combined. Salmonella Typhimurium, Heidelberg, Hadar, Kentucky, and Thompson were the 5 most frequently isolated serovars. Approximately 60% of the S. Typhimurium were isolated from cattle, whereas over 90% of the S. Heidelberg, Hadar, Kentucky, and Thompson were isolated from chickens. Salmonella Enteritidis was rarely isolated. There was an increasing trend in isolates from chickens, cattle, and pigs, and a decreasing trend in isolates from turkeys. Temporal clusters were observed in 11 of 15 serovars examined in chickens (S. Anatum, Heidelberg, Infantis, Kentucky, Mbandaka, Montevideo, Nienstedten, Oranienburg, Thompson, Typhimurium, and Typhimurium var. Copenhagen), 5 of 5 serovars in cattle (S. Dublin, Montevideo, Muenster, Typhimurium, and Typhimurium var. Copenhagen), and 1 of 3 serovars in pigs (S. Typhimurium). Short-duration clusters may imply point source infections, whereas long-duration clusters may indicate an increase in the prevalence of the serovar, farm-to-farm transmission, or a wide-spread common source. A higher concentration of clusters in the winter months may reflect greater confinement, reduced ventilation, stressors, or increased exposure to wildlife vectors that are sharing housing during the winter. Detection of large clusters of Salmonella may have public health implications in addition to animal health concerns.     

Multidrug resistance and distribution of Salmonella serovars in slaughtered pigs

The present study was undertaken to estimate the occurrence and distribution of multidrug resistance (MDR) among Salmonella serovars isolated from slaughtered pigs at Debre Zeit, Ethiopia. A total of 501 different samples were examined of which 42 (41.6%) of 101 mesenteric lymph nodes, 22 (21.8%) of 101 tongues, 17 (16.8%) of 101 caecal contents, 11 (11.1%) of 99 livers and two (2%) of 99 muscle (diaphragm and abdomen) samples were Salmonella positive. Of the 94 Salmonella isolates representing 15 different serovars, 69 (73.4%) were multidrug resistant (resistance to two or more antimicrobials). Among the Salmonella serovars a high level of MDR was observed in S. Hadar, S. Kentucky, S. Blockley and S. Enteritidis mainly to tetracycline (88.6%), streptomycin (82.9%), nitrofurantoin (74.3%), nalidixic acid and ciprofloxacin (42.9% each), sulfisoxazole (21.1%) and spectinomycin (20%). The pattern of MDR varied from two to eight antimicrobials among the resistant Salmonella serovars. The common profiles of resistance among the MDR serovars were the combined resistance to nitrofurantoin, streptomycin and tetracycline (R type NitStrTet, 51.4%), ciprofloxacin, nalidixic acid and nitrofurantoin (R type CipNalNit, 10%), ciprofloxacin, nalidixic acid, spectinomycin, streptomycin, sulfisoxazole and tetracycline (R type CipNalSptStrSulTet, 14.3%) and to ciprofloxacin, kanamycin, nalidixic acid, neomycin, nitrofurantoin, streptomycin and tetracycline (R type CipKanNalNeoNitStrTet, 10%). Results of the present study indicate the widespread occurrence and distribution of MDR Salmonella serovars in slaughtered pigs which could be a potential source of human MDR Salmonella infections.     

The distribution of Salmonella serovars in chicken and humans in Lithuania

We studied serovars of Salmonella strains isolated from chicken and humans in Lithuania over the period from 2000 to 2004. Salmonella strains were isolated and identified according to the techniques recommended by International Organisation for Standardization (Microbiology of Food and Animal Feeding Stuff--Horizontal Method for the Detection of Salmonella, 1998, ISO, Geneva). The per cent of infected flocks with Salmonella in separate years was between 1.01% and 3.2% during the period of investigation. The contamination rate of broiler legs and breasts was higher (2.36% and 4.25%) than that of wings (0.82%). Eighteen serovars of Salmonella were identified from the total 300 isolated samples. The most prevalent serovars in chicken were Salmonella Enteritidis, Salmonella Infantis and Salmonella Typhimurium. Other serovars such as Salmonella Montevideo, Salmonella Djugu, Salmonella Isangi, Salmonella Bovismorbificans, Salmonella Mbankada, Salmonella Hadar were detected only in one to two samples. In general, similar serovars of Salmonella were found in humans and chicken (S. Enteritidis and S. Typhimurium), although distinct serovars were found only in humans or only in chicken. Analysis of the distribution of Salmonella serovars in humans during the seasons of the year indicated that the highest incidence of Salmonella was in Summer and in the beginning of Autumn. Analysis of the distribution of serovars during the study period indicated that there is a shift over time in both humans and chicken.     

Salmonella enterica subsp. enterica isolated from chicken carcasses and environment at slaughter in Reunion Island: prevalence, genetic characterization and antibiotic susceptibility

Salmonella contamination of 71 chicken broiler flocks was investigated at the slaughterhouse in Reunion Island between October 2007 and January 2009. Samples were collected from live broiler chickens and chicken carcasses as well as the slaughterhouse environment. Salmonella spp. was isolated from 40 of 71 (56 % with a confidence interval 5 % [45–67]) broiler chicken flocks at slaughter. The most prominent serovars were Blockley (31 %), Typhimurium and Brancaster (14 %), Hadar (10 %), Salmonella multidrug resistant clinical organisms serotypes 1,4,[5],12:i:-, and Virchow (8 %) and Livingstone, St. Paul, Seftenberg, Llandoff, Infantis and Indiana. At the farm, 27 % of the broiler chicken flocks tested positive for Salmonella spp. Salmonella spp. was isolated from 124 of 497 environmental samples (25 %). In most cases, there was no relationship between pulsed field gel electrophoresis (PFGE) pattern and antibiotic resistance pattern. The predominant Salmonella serovars were susceptible to most of the tested antibiotic drugs, but S. Hadar exhibited multidrug resistance. This study highlighted the primary source of Salmonella was the farm of origin and downstream stages in processing could not remedy to but amplify this Salmonella contamination.     

Use of molecular fingerprinting to assist the understanding of the epidemiology of Salmonella contamination within broiler production

1. We analysed Salmonella isolates by conventional sero- and phage-typing, as well as by molecular techniques within the broiler production chain in two integrated companies. The most prevalent serovars were selected for genetic fingerprinting. 2. Isolates were first screened by plasmid profiling; subsequently, the most common plasmid types within the prevalent zoonotic serovars (enteritidis and typhimurium) and S. agama were further characterised by PstI-SphI ribotyping, and XbaI pulsed field gel electrophoresis (PFGE). 3. Salmonella binza, S. kedougou, and S. 4,12:d:- were endemic in the feed mills over long periods of time, and a variety of plasmid types for each of the serovars were found in the premises. 4. A similar situation was found with S. binza and S. senftenberg within the hatchery in company B. The Salmonella serovars which were resident in those locations were also the ones most widely distributed throughout the broiler flocks. 5. Plasmid profiling was useful to subdivide clusters of isolates within serovars, but for each serovar a high percentage (36 to 79%) of the isolates tested fall within a prevalent plasmid type. 6. A more detailed genetic analysis of the isolates by a multiple typing approach allowed for further strain differentiation, and allowed some epidemiological conclusions to be drawn.     

Evaluation of a French ELISA for the detection of Salmonella Enteritidis and Salmonella Typhimurium in flocks of laying and breeding hens

In France, the regular and compulsory detection of Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) in flocks of breeding and laying hens is based on bacteriological examination of environmental swabs and faeces samples. The aim of this study was to compare this bacteriological examination with a serological method (ELISA) developed in our laboratory. This ELISA was first evaluated by use of artificially infected hens. During these experimental infection studies, several groups of hens were inoculated with SE, ST, different vaccines and different Salmonella serovars to calculate the experimental parameters of our ELISA. Then, in a field study, 43 flocks were followed monthly using two bacteriological samples (environmental swab and pool of faeces) and 20 serological samples (sera or yolks). Twenty-seven flocks without SE or ST gave a negative serological response throughout their surveillance. Among the 10 various serovars different from SE and ST isolated in this study, S. Heidelberg, S. Agona and S. Hadar gave seropositive results in seven flocks. Consequently, this ELISA was not specific of SE and ST as it detected serovars sharing or not common antigens with SE and ST. Seropositive results were also obtained each month for two flocks where no Salmonella could be isolated. Finally, in seven flocks found infected with SE or ST, the positive ELISA results appeared later than the bacteriological detection. Therefore, for the detection of chicken flocks recently infected with SE or ST, bacteriological examination currently used in France seems to be more appropriate than this ELISA.     

Survey of the prevalence of Salmonella species on commercial laying farms in the United Kingdom

A survey of salmonella infection on 454 commercial layer flock holdings in the uk was carried out between October 2004 and September 2005. Fifty-four (11.7 per cent, 95 per cent confidence interval 9.3 to 14.0 per cent) were salmonella positive. The most common serovar identified was Salmonella Enteritidis at a prevalence of 5.8 per cent, and 70 per cent of these isolates were phage types 4, 6, 7 and 35. Salmonella Typhimurium was the second most prevalent serovar, found in 1.8 per cent of the farms. Of the three other serovars given top priority by the eu because of their public health significance, Salmonella Virchow and Salmonella Infantis were each isolated from one holding, but Salmonella Hadar was not isolated from any of the holdings. Analysis of antimicrobial resistance patterns revealed that over 76 per cent of the isolates were sensitive to all of the 16 drugs tested, and all the isolates were sensitive to ciprofloxacin, gentamicin, ceftazidime, apramycin, amikacin, amoxicillin/clavulanic acid, neomycin and cefotaxime.     

A molecular epidemiologic investigation of Salmonella from a meat source to the feces of captive cheetah (Acinonyx jubatus).

Low cheetah (Acinonyx jubatus) birth rates were observed for a long time in a captive breeding facility in which Salmonella, which was possibly present in contaminated beef, was isolated from still-born lion (Panthera leo) cubs. Salmonella, including 14 isolates of Salmonella serovar typhimurium and 19 isolates of Salmonella serovar muenchen, was subsequently isolated 47 times from 378 meat samples at the facility during a 13-mo period. Salmonella, including 26 isolates of S. serovar typhimurium, 10 of S. serovar muenchen, and 11 other serovars, also was isolated 54 times from 119 fecal samples. Only three plasmid profiles were identified in 59 S. typhimurium isolates from both meat and fecal samples. Although random-amplified polymorphic DNA fingerprinting using different primers in the polymerase chain reaction was able to distinguish between S. typhimurium and S. muenchen and to demonstrate similar chromosomal DNA fingerprints in some of the isolates from meat and feces, the results were not consistent enough to prove that the Salmonella in the feces originated from contaminated meat. However, the predominance of only two serovars in the meat fed to carnivores and in the feces of these animals suggests that the meat was the source of the Salmonella organisms in the feces.     

鸡源大肠杆菌的耐药性监测及生物学特性研究

从山东省诸城地区6个集约化养鸡场采集50只病死鸡病料,从中分离鉴定得到32株大肠杆菌,对其进行了12种常规药敏试验,发现分离的菌株有不同程度的耐药性。对14株优势血清型菌株进行了质粒DNA提取分析,然后用Hind Ⅲ限制性内切酶对质粒进行了酶切。结果表明,质粒的得率为100%,来源相同的菌株具有相同或相似的质粒图谱,也就是说它们有共同的起源;来源不同的菌株的质粒图谱一般不同,即有不同的起源。将血清型和质粒图谱比较,结果发现,同一血清型可以有不同的质粒图谱,不同血清型可以有相似的质粒图谱,血清型与质粒图谱没有直接的联系。     

Prevalence, incidence and geographical distribution of serovars of Salmonella on dairy farms in England and Wales

A study of randomly selected dairy farms in England and Wales was made between October 1999 and February 2001 to estimate the prevalence and incidence of Salmonella serovars. The farms were enrolled through five milk-buying companies, which represented 63 per cent of the dairy farms in England and Wales, and they were sampled on up to four occasions (449 farms at visit 1, 272 farms at visit 2, 251 farms at visit 3 and 243 farms at visit 4). In total, 19,296 samples of pooled faecal pats and slurry were collected. The farm-specific prevalence of all serovars of Salmonella ranged from 12.1 per cent (95 per cent confidence interval [CI] 8.2 to 16.0 per cent) to 24.7 per cent (95 per cent CI 19.4 to 30.1 per cent) at each visit. The most common serovars identified were Salmonella Dublin (3.7 to 6.6 per cent farm-specific prevalence at each visit), Salmonella Agama (1.8 to 7.6 per cent) and Salmonella Typhimurium (2.6 to 4.1 per cent) The prevalence varied by region and month of sampling and increased in late summer. The incidence rate of all serovars of Salmonella was 0.43 (95 per cent CI 0.34 to 0.54) cases per farm-year at risk. There was no significant difference between the incidence rates of the common serovars S Typhimurium (0.07), S Dublin (0.06) and S Agama (0.13). A total of 29 Salmonella serovars were isolated. Few of the isolates were resistant to the 16 antimicrobial agents tested, except the isolates of S Typhimurium dt104, of which 67.9 per cent were resistant to at least five of them.     

Plasmid analysis and epidemiology of Salmonella enteritidis infection in three commercial layer flocks.

Ninety-six S. enteritidis isolates obtained from three commercial layer flocks in 1988-90 were examined following DNA extraction, restriction enzyme digestion, and gel electrophoresis for plasmid size profiles and restriction fragment length polymorphisms (RFLPs). The S. enteritidis isolates from the three flocks had three, eight, and two different plasmid profiles, respectively. Only four isolates from one flock lacked plasmids. A 36-megadalton (mDa) (54-kilobase) plasmid was present in 73% of the isolates, either alone or in combination with other plasmids. Isolates with only the 36-mDa plasmid had identical RFLPs. The diversity of plasmid profiles was greater than that of phage-types among isolates from the three flocks: 12 unique plasmid profiles vs. four phage-types. Mixed infections with S. enteritidis strains having distinct plasmid profiles occurred in all three flocks. Reinfection of these flocks in 1990 with one or more of the strains obtained earlier was evident, because some of the original isolates and the 1990 isolates had matching plasmid profiles and were of the same phage-types. Isolates from both environmental and tissue samples, examined from one flock, were found to share the same plasmid profile and phage-type.     

Antimicrobial resistance pattern of Salmonella serotypes isolated from apparently healthy slaughtered camels (Camelus dromedarius) in eastern Ethiopia

A total of 714 samples consisting of faeces, mesenteric lymph nodes, liver, spleen, abdominal and diaphragmatic muscles (each 119) were collected from November 2001 to April 2002 from apparently healthy slaughtered camels (Camelus dromedarius) in eastern Ethiopia. One hundred sixteen (16.2%) Salmonella strains belonging to 16 different serovars were isolated. All Salmonella strains isolated were examined for antimicrobial resistance to 17 selected antimicrobials. The minimum inhibitory concentration (MIC) values were determined by the microdilution broth test. Fifty-two (44.8%) of the Salmonella isolates were resistant to one or more antimicrobials. Thirty-nine of the 52 (75%) resistant Salmonella serovars exhibited multiple resistance to up to eight different antimicrobials. Among the serovars tested, S. Typhimurium, S. Heidelberg, S. Braenderup and S. Hadar displayed multiple resistance mainly to streptomycin (35.3%), spectinomycin (28.4%), sulfamethoxazole (25.0%), ampicillin (24.1%), trimethoprim (22.4%), trimethoprim/sulfamethoxazole (18.9%), tetracycline (12.9%) and colistin (11.2%). All Salmonella strains tested were susceptible to ciprofloxacin, nalidixic acid, gentamicin, kanamycin and neomycin. The present study showed the importance of camels as a potential source of single and multiple resistant Salmonella strains to different antimicrobials that are also used in the public health sector for the treatment of different bacterial diseases in Ethiopia.     

Salmonella serovars and antimicrobial resistance patterns on a sample of high seroprevalence pig farms in England and Wales (2003-2008)

Following the introduction of a national abattoir-based monitoring programme for Salmonella in pigs, advisory visits were made to pig farms in England and Wales with high Salmonella seroprevalence assessed by muscle tissue fluid (meat juice) ELISA. Samples (n = 15 790), including pooled pen floor faeces (n = 12 136), were collected for Salmonella culture from 296 farms, between October 2003 and February 2008. Salmonella was isolated from 4489 (28%) of all samples collected, including 3301 (27%) of pooled pen floor faecal samples, from 270 (91%) of farms visited. Salmonella Typhimurium and S. Derby were the most prevalent serovars, representing 64% and 16% of isolates serotyped, respectively. The main phage types of S. Typhimurium identified were U288 and DT193. Antimicrobial resistance (AMR) was seen in 92% of isolates tested, with the highest frequencies of resistance occurring to tetracyclines (T), sulphonamide compounds (SU), ampicillin (AM), sulphamethoxazole/trimethoprim (SXT), streptomycin (S) and chloramphenicol (C). Fifty-nine AMR patterns were observed, the most frequent of these being T, AM, SXT, C, S, SU, seen in 35% of isolates tested. Multi-drug resistance was commonly found, with 67% of isolates submitted for AMR testing showing resistance to between four and nine antimicrobials.     

Sources of Salmonella contamination during broiler production in Eastern Spain

Prevention of Salmonella contamination of poultry products requires detailed knowledge of the main sources associated with its presence in the production system. The aims of this study were to determine the main sources of Salmonella contamination in broiler production during growing, to assess the risk factors for Salmonella contamination at the end of the rearing period and to determine the main serovars involved in broiler production systems in Eastern Spain. A total of 65 different broiler houses from different farms were sampled. Each house was sampled at different times during the rearing period. First, when the previous flock was taken to the slaughterhouse, samples of dust, surfaces and previous flock faeces were collected. After cleaning and disinfection (C&D), samples of dust and surfaces were also taken. On the first day of rearing, samples of water, bedding, farming boots, meconiums, delivery-box liners and feed were collected. During rearing, feed samples were taken directly from the truck and from feeders. On slaughter day, samples of dust, surfaces, water, feed and faeces were also collected. Finally, two days after slaughter, carriers (rodents, flies and beetles) were trapped. All samples collected were analysed according to ISO 6579:2002 (Annex D) and positive samples were serotyped in accordance with Kauffman-White-Le-Minor technique. Our results showed that all different types of samples collected were contaminated with Salmonella (prevalence ranged between 1.5% and 38.6%). The most contaminated samples related with poultry production were: delivery-box liners (32.0%), faeces samples (31.2%), dust samples (25.0%), farming boots (19.7%) and feed from feeders (16.0%). However, the most important risk factors for Salmonella contamination of the flocks at the end of the rearing period were Salmonella status of the house after cleaning and disinfection, Salmonella status of day-old chick flocks and feed from feeders. Twenty-one different serovars were isolated from the samples analysed. The most prevalent were in decreasing order: Salmonella Enteritidis (52.9%), S. Hadar (17.8%), S. Virchow (8.9%) and S. Ohio (5.4%). The study suggested that there are many sources for Salmonella contamination and persistence in broiler production. Hence, the whole production chain needs to be controlled to eradicate the bacteria from primary production.     

Prevalence of Salmonella spp. in pigs, chickens and ducks in the Mekong Delta, Vietnam

In order to determine the prevalence of Salmonella spp. in domestic animals in 6 provinces of the Mekong Delta, Vietnam, 1,098 fecal or intestinal content samples from pigs, chickens, and ducks were examined in the period from July to October, 2000. Salmonella spp. were isolated from 78 (7.1%) of the total samples, which included 23 (5.2%) of 439 pigs, 24 (7.9%) of 302 chickens, and 31 (8.7%) of 357 ducks. From those samples, 80 Salmonella strains were isolated and 25 serovars were identified. The predominant serovars were S. Javiana, S. Derby, and S. Weltevreden. S. Javiana and S. Weltevreden were detected together in pigs, chickens, and ducks. These results indicate that the serovars of Salmonella are widely distributed in domestic animals in the Mekong Delta, Vietnam.     

A national survey to estimate the prevalence of Salmonella species among Canadian registered commercial turkey flocks.

In 1990-1991, a national survey was conducted to estimate the prevalence of Salmonella species among Canadian commercial turkey flocks. Two hundred and seventy flocks were randomly selected across Canada. The proportion sampled from each province was selected according to each province's share of the national turkey market. Samples, consisting of 12 pooled litter and four pooled dust samples, were used to determine the Salmonella status of the environment of each flock. Additionally, a one kilogram sample of feed was taken from each flock premise. Salmonella was recovered from environmental samples in 234/270 (86.7%) of flocks and from feed samples in 26/266 (9.8%) of flocks. Forty-eight different Salmonella serovars were isolated from flock environmental samples. The most prevalent serovars were S. anatum, S. hadar, S. agona, S. heidelberg and S. saintpaul which were isolated from 53/270 (19.6%), 49/270 (18.1%), 49/270 (18.1%), 42/270 (15.6%) and 34/270 (12.6%) flocks, respectively.     

Comparison of the prevalence of Salmonella infection in layer hens from commercial layer farms with high and low rodent densities

A comparison on the prevalence of Salmonella infection in layer hens from commercial layer farms with high and low rodent densities was investigated. Out of 280 laying hens sampled from three commercial layer farms with high rodent densities, Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis) was isolated from 20 (7.14%) hens and Salmonella enterica subsp. enterica serovar Infantis (Salmonella Infantis) from three (1.07%) hens. In contrast, layer hens sampled from four commercial layer farms with low rodent densities were negative for any salmonellae. Significant differences (P < 0.05) in the isolation rates of Salmonella from various organs of infected layer hens were also noted. For Salmonella Enteritidis, liver (55.0%) and the oviduct (55.0%) had the highest isolation rates while all Salmonella Infantis isolates were from the oviduct. Pulsed field gel electrophoresis (PFGE) analysis of BlnI-digested chromosomal DNA of Salmonella Enteritidis isolated from layer hens and rodents showed similar patterns. PFGE analysis of Salmonella Infantis isolated from layer hens, rodents, eggs, and the environment yielded identical patterns. In this study, the significantly higher prevalence rate (P < 0.05) of Salmonella Enteritidis and Salmonella Infantis in layer hens from high rodent density farms could be attributed to the high rodent population density. The persistent Salmonella Enteritidis and Salmonella Infantis infection inside layer houses may have been amplified by the increasing numbers in the rodent population over the years, which increased the opportunity for environment-rodent-chicken interaction and the transmission of salmonellae to chickens. Monitoring of salmonellae from rodents inside poultry premises is recommended to be an effective additional tool in the assessment of the Salmonella status of layer flocks.     

Contamination of Salmonella blockley in the environment of a poultry farm.

Cecal and environmental samples were collected and examined for the presence of Salmonella on a farm where a high prevalence of Salmonella blockley in chickens was observed. Of 895 cecal and 525 environmental samples examined, 242 (27.0%) and 202 (38.5%) samples, respectively, yielded S. blockley. From the analysis of plasmid profile patterns, 11 different plasmid profile patterns were found among 444 isolates, with plasmid patterns c and d the most frequent among the isolates from ceca and the environment. Salmonella blockley was isolated from environmental samples such as floor litter, walls, drinking water, waste water, dust, and soil collected when barns were occupied and was positive in drinking water, waste water, and soil when samples were collected from empty barns with occupied neighboring barns, but it was negative in all environmental samples with the exception of soil when the environmental samples were collected from empty barns with empty neighboring barns.     

The occurrence and distribution of Salmonella enteritidis and other serovars on California egg laying premises: a comparison of two sampling methods and two culturing techniques

Between the summer of 1998 and the winter of 2000, Salmonella analysis was performed on 2128 single and 532 pooled manure drag swabs obtained from 133 California commercial egg laying farms. The isolation of Salmonella from all rows and from all flocks using single or pooled swabs was 80% and 92%, respectively. Hence, there was no statistical difference between single vs. pooled swabs in terms of identifying Salmonella on a row or flock basis. A total of 14 serogroups comprising 44 serotypes were isolated from 123 of 133 farms. When the top 10 serotypes were considered, there was no significant difference in the range of serotypes isolated by the two culturing methods. The overall S. enteritidis prevalence for California flocks was 10.5% (14/133). The overall row prevalence for S. enteritidis for all the farms was 1.1% (24/2128), and the overall pool prevalence was 2.4% (13/532). Sixty percent (12/20) of the S. enteritidis isolates from the positive farms were phage type 4, and 40% (8/20) represented five other phage types (1, 6B, 7, 8, and 28).     

Frequency of Salmonella enteritidis and other salmonellae in the ceca of spent hens at time of slaughter.

A study was conducted to determine the frequency of Salmonella enteritidis (SE) and other Salmonella serovars in the cecal contents of spent laying hens at a hen-processing plant in the southeastern United States over a 4 1/2-month period, from October 1990 through February 1991. A total of 1920 pooled cecal samples (three ceca per sample) from 38 flocks representing 23 producers were obtained and tested for the presence of SE and other Salmonella serovars. A total of 359 samples (18.7%) from 37 of the 38 flocks (97.4%) showed characteristic reactions for salmonellae on triple sugar iron agar (TSIA) slants. Twenty-nine of the 359 Salmonella-positive samples (8.1%) were Group D-positive, all of which were found to be SE on further serotyping. The SE-positive samples were from seven of the 38 flocks (18.4%); four flocks originated from the USDA/APHIS-designated Northern Region of the United States, and three were from the Southeastern Region. Serotyping of the 330 TSIA-positive Group-D negative Salmonella revealed 37 different serovars. S. heidelberg, the predominant serovar, was identified in 49.1% of these isolates.