Bovine Salmonellosis Research Articles

Salmonellosis in adult cattle in Central Argentina: case series.

Salmonellosis is an infectious disease caused by bacteria belonging to the Salmonella genus. Bovine salmonellosis is more frequent in young cattle under intensive overcrowd husbandry conditions, and therefore uncommon in adults. We report four outbreaks of clinical salmonellosis due to Salmonella Typhimurium, Salmonella Newport and Salmonella Dublin provoking outbreaks of diarrheic/septicemic disease in adult cattle of Central Argentina. Anamnesis information, clinical, pathological, and bacteriological findings were retrospective analyzed. This report emphasizes the importance to include salmonellosis among the differential diagnosis of clinical enteric/septicemic disease in adult cattle under different husbandry conditions in Argentina. The source of Salmonella could not be established in these outbreaks.

A Review on Antimicrobial Resistance of Bovine Salmonellosis and Its Public Health Importance: One Health Approach

A Review on Antimicrobial Resistance of Bovine Salmonellosis and Its Public Health Importance: One Health Approach

Prevalence and Molecular Characterization of Salmonella Serovars Isolated from Diarrheic Cattle and Buffalo-Calves

In the first 10 weeks of life, bovine salmonellosis is the most serious infection typically affects calves. The aim of this work was to study the prevalence, antimicrobial susceptibility profile, attributes of some virulence and resistance genes of Salmonella isolated from diarrheic cow and buffalo-calves. A total of 200 fecal samples from cow and buffalo-calves were bacteriologically examined for isolation of Salmonella species. The percent of positive cases (n= 65 /200) was 32.5%. Serological typing of the recovered Salmonella isolates produced eight serotypes, Salmonella Typhmurium (13.8%), S. Anatum (7.6%), S. Sanktjohann (1.5%), S. Salami (20%), S. Mississippi (24.6%), S. Stratford (13.8%), S. Enteritidis (7.6%) and S. Saintpaul (10.7%). Upon ower knowledge, this is the first record of isolation of S. Sanktjohann from diarrheic calves in Egypt. The results revealed a higher incidence of salmonellosis in Spring (57.6%) followed by Winter (27.9%). Also, the incidence of salmonellosis was more recorded in cow calves (43.58%) than buffalo calves (16.86%). Antimicrobial susceptibility testing showed that the highest sensitivity levels were found for nalidixic acid (75%), enrofloxacin (62.5%), and chloramphenicol (50%) whereas, all isolates (100%) were resistant to ampicillin, gentamicin, streptomycin, and doxycycline. The 4 virulence genes (invA, avrA, stn, spvC) were found in the 8 examined Salmonella isolates. The blaTEM and tetA(A) resistance gene were detected in all isolates that were resistant to ampicillin and doxycycline. Tetracycline resistance gene (floR) was identified in 5 isolates; the sul1 gene was present in Sulphamethoxazole resistant isolates and the dfrA gene was present only in 2 isolates (S. Sankjohan and S. Mississippi) which existed resistance to trimethoprim. By comparing the stn gene sequence data of both S. Sanktjohann and S. Stratford with other Salmonella strains from the GeneBank the point mutation (Threonine 371 to Serine) was identified. In conclusion, this study proved the presence of different virulent and MDR salmonella isolates in diarrheic calves that make persistence shedding of microorganism into the environment. Moreover, antimicrobial sensitivity testing should be performed prior to treatment of Salmonella infection.

Retrospective application of transposon-directed insertion-site sequencing to investigate niche-specific virulence of Salmonella Typhimurium in cattle

BackgroundSalmonella enterica subspecies enterica is an animal and zoonotic pathogen of global importance. Cattle are a significant reservoir of human non-typhoidal salmonellosis and can suffer enteric and systemic disease owing to the ability of Salmonella to survive within the bovine lymphatic system and intestines. Contamination of food can occur due to the incorporation of contaminated peripheral lymph nodes or by direct contamination of carcasses with gut contents. It is essential to understand the mechanisms used by Salmonella to enter and persist within the bovine lymphatic system and how they differ from those required for intestinal colonization to minimize zoonotic infections.ResultsTransposon-directed insertion site sequencing (TraDIS) was applied to pools of mutants recovered from mesenteric lymph nodes (MLNs) draining the distal ileum of calves after oral inoculation with a library of 8550 random S. Typhimurium mini-Tn5Km2 mutants in pools of 475 mutants per calf. A total of 8315 mutants representing 2852 different genes were detected in MLNs and their in vivo fitness was calculated. Using the same improved algorithm for analysis of transposon-flanking sequences, the identity and phenotype of mutants recovered from the distal ileal mucosa of the same calves was also defined, enabling comparison with previously published data and of mutant phenotypes across the tissues. Phenotypes observed for the majority of mutants were highly significantly correlated in the two tissues. However, 32 genes were identified in which transposon insertions consistently resulted in differential fitness in the ileal wall and MLNs, suggesting niche-specific roles for these genes in pathogenesis. Defined null mutations affecting ptsN and spvC were confirmed to result in tissue-specific phenotypes in calves, thus validating the TraDIS dataset.ConclusionsThis validation of the role of thousands of Salmonella genes and identification of genes with niche-specific roles in a key target species will inform the design of control strategies for bovine salmonellosis and zoonotic infections, for which efficacious and cross-protective vaccines are currently lacking.

Geospatial and temporal changes in Wisconsin bovine Salmonella enterica isolates between 2006 and 2014

Bovine salmonellosis carries a high economic burden for cattle operations and presents a public health risk due to zoonosis. The objective of this study was to determine the frequency and concurrent location of Salmonella enterica subspecies enterica serovars isolated in Wisconsin from bovine diagnostic samples submitted to the Wisconsin Veterinary Diagnostic Laboratory from 2006 to 2014, by using geographic information system and statistical analysis tools. Salmonella serovars and zip codes of animal location were retrospectively collected. Accessions were limited to bovine fecal and tissue samples that yielded a typeable Salmonella serovar either by culture or polymerase chain reaction. A total of 4,829 accessions were included in the study that yielded definitive Salmonella serovars. The 5 most frequently isolated serovars were Dublin [23%), Cerro (15%), Newport (14%), Kentucky (9%), and Montevideo (9%). After normalization, the region with the highest incidence was the east-central region for all serovars combined. Overall incidence decreased during the 9 years except for Salmonella ser. Cerro, which increased. Incidence of Salmonella serovars in densely populated dairy regions in Wisconsin was variable. Continued study and monitoring of the spatial disease ecology for salmonellosis in Wisconsin is warranted to improve animal health and milk production, and minimize the risk of zoonosis.

Low prevalence of Salmonella in Swedish dairy herds highlight differences between serotypes

Legislated Salmonella control in Sweden has been in place since the 1960s. The purpose of this study was to investigate presence of Salmonella antibodies in dairy cattle herds and to provide a basis for decisions on how surveillance and control can be improved. Bulk milk samples from all Swedish dairy herds (n=4 683) were analysed with two different ELISAs; one detecting antibodies against Salmonella Dublin (Dublin ELISA), and one detecting antibodies against several of the serotypes causing bovine salmonellosis including S. Dublin (Bovine ELISA). Information about herds, i.e. geographical location, local animal density, number of test positive herds within 5km, animal trade and herd size, was based on register data.The results confirm a very low prevalence of Salmonella in Swedish dairy herds throughout the country with the exception of an island in the southeast. The test positive herds split into two groups; 41 herds (1%) positive in the Dublin ELISA, and 101 herds (2%) positive in the Bovine ELISA but negative in the Dublin ELISA. Geographical location of positive herds, and comparison of the results of the screening with serotypes previously isolated from some of the herds, indicated that the first group represents herds presently or previously infected with S. Dublin while the second group represents herds presently or previously infected with other serotypes. Differences in serological status between herds in different regions, of different size, with different animal purchase patterns et cetera, were tested using logistic regression.Presence of positive herds within 5km was significantly associated to testing positive. For herds testing positive in the Dublin ELISA, significant associations were also seen with herd size. Purchase of animals during the last year was not significantly associated with the outcome in the final models.We conclude that for future surveillance, the Bovine ELISA can be used to help in identifying infected herds, and the Dublin ELISA can be used to distinguish herds with S. Dublin infections. The geographical clustering of test positive herds could facilitate future surveillance and disease control interventions. The results highlight differences between S. Dublin and other serotypes, e.g. concerning prevalence and degree of geographical clustering. Further studies on risk factors and potential local spread of Salmonella is warranted, particularly in the regions with clustering of S. Dublin infected herds.

A case study on Salmonella enterica serovar Typhimurium at a dairy farm associated with massive sparrow death.

Background Salmonella enterica Typhimurium (S. Typhimurium) is the most common cause of bovine salmonellosis in Japan and where it is also cause of salmonellosis in wild birds. In 2008, a postpartum cow at a dairy farm developed diarrhea caused by S. Typhimurium. The herd was extensively surveilled for Salmonella sp. and we characterized bacterial isolates from this and other cows to determine the source of infection.ResultsEight isolates of S. Typhimurium from cattle were identified as phage type DT40 and showed a 100 % similarity by pulsed-field gel electrophoresis and the same or similar multiple-locus variable-number tandem-repeat analysis profiles as those of S. Typhimurium isolated from dead sparrows (Passer montanus) collected at Asahikawa in 2006. S. Typhimurium DT40 was considered to be a major cause of high sparrow mortality in Hokkaido in 2005–2006 and 2008–2009, suggesting that DT40 maintained in sparrows was transmitted to cattle.Conclusions S. Typhimurium DT40 may be transmitted from sparrows to dairy cattle.

A Review on the Public Health Importance of Bovine Salmonellosis

Salmonellosis is an infectious disease of human and animal caused by organisms of the two species of Salmonella (S. enterica and S. bongori). A Salmonella pathogen are highly adaptive and potentially pathogenic to human and other domestic animals; young, pregnant and lactating animals are the most susceptible and are capable of producing a serious of infections having foodborne zoonosis importance. Enteric disease is the commonest clinical manifestation, but a wide range of clinical signs, which include acute septicaemia, abortion, arthritis and respiratory disease, may be seen.Worldwide there are 16 million annual cases of typhoid fever, 1.3 billion cases of gastroenteritis and 3 million deaths. Poultry, egg, meat, dairy products and fruits and vegetables serve as vehicles of transmission. Most human salmonellosis cases are foodborne, but each year infections are also acquired through direct or indirect animal contact in homes, veterinary clinics, zoological gardens, farm environments or other public, professional or private settings. Salmonella passes through M-cells overlying Peyer’s patches, through dendritic cells or through the epithelial lining in the lower part of small intestine or proximal colon to arrive in the sub epithelial location which is also transported to extra intestinal sites such as the liver, spleen and mesenteric lymph nodes. Salmonella pathogens are common in cattle and potentially infect human that come in contact with cattle. Bovine salmonellosis is caused by S. typhimurium and dublin. The disease in cattle is characterized by septicemia, acute or chronic entritis or abortion. Salmonella entrica sub species entrica develop a resistance to multi antibiotics in which results in increasing failure of treatment and severity of infection. Basic hygiene practices and the implementation of scientific based management strategies can efficiently mitigate the risks associated with animal contacts. However, the general public is frequently unaware of the specific disease risks involved and high-risk behaviors are common. The disease can be also controlled by vaccination of cattle.

Bovine salmonellosis in Northeast of Iran: Frequency, genetic fingerprinting and antimicrobial resistance patterns of Salmonella spp.

ObjectiveTo evaluate serovar and antimicrobial resistance patterns of Salmonella spp isolated from healthy, diseased and necropsied cows and calves in this observational study. MethodsNineteen isolates recovered from feces and tissues of salmonellosis-affected animals of two commercial farms in north-east of Iran. In second part of the study, the two farms were sampled 4 times with an interval of 2 month. The samples included calves' feces, adult cows' feces, feeds, water, milk filters, and milk fed to calves. Five Salmonella were isolated from 332 fecal samples collected from calves and peri-parturient cows. No Salmonella was recovered from water, feed, milk filers and milk fed to calves. ResultsSalmonella Typhimurium was the most frequently isolate among all sero-groups. S. Dublin was only accounted for 8% (two out of 24) of isolates. Isolated Salmonella strains were used for the ERIC PCR DNA fingerprinting assay. Our results grouped Salmonella isolates into 3 clusters, suggesting that specific genotypes were responsible for each sero-group of Salmonella. The results also revealed diversity among Salmonella isolates in cluster III (sero-group B). Eighteen out of 19 Salmonella spp. were resistant to oxytetracycline. Five isolates out of 19 showed more than one drug resistance. Multi-drug resistance was seen only among Salmonella Typhimurium isolates. Enrofloxacin was the most susceptible antibiotic against all isolates in this study. ConclusionThe emergence of multiple antibiotic-resistant strains of Salmonella Typhimurium should be of great concern to the public. No correlation between ERIC fingerprinting and resistance patterns of Salmonella isolates was found, which indicates resistance to antimicrobial agents was not related to specific genetic background.

Molecular typing of Salmonella enterica serotype Typhimurium and serotype 4,5,12:i:- isolates from cattle by multiple-locus variable-number tandem-repeats analysis

To evaluate the usefulness of multiple-locus variable-number tandem-repeats analysis (MLVA) as a tool for the epidemiological analysis of bovine Salmonellosis, Salmonella enterica serotype Typhimurium and serotype 4,5,12:i:- isolates (544 and 18, respectively) obtained from cattle in Hokkaido, Japan, between 1977 and 2009, were characterised by MLVA. MLVA identified 184 profiles versus 121 profiles identified by pulsed-field gel electrophoresis (PFGE). Cluster analysis of the MLVA profiles demonstrated 3 major clusters (A, B, and C) and 3 minor clusters (D, E, and F). Cluster A was associated with PFGE cluster I, which included isolates of definitive phage type 104 (DT104), while cluster C was associated with PFGE cluster VII, which has been disseminating among cattle since 2002. An isolate of serotype Typhimurium belonging to MLVA cluster F, in which 10 serotype 4,5,12:i:- isolates were included, was found to have an MLVA profile closely related to those of serotype 4,5,12:i:- isolates, suggesting that such a strain may be an ancestral candidate for serotype 4,5,12:i:-. Overall, the discriminatory power of MLVA was higher than that of PFGE, and MLVA differentiated between the isolates of the DT104 family, which appeared to be clonal by PFGE. However, this depended on PFGE clusters because PFGE allowed greater discrimination between isolates within PFGE cluster IV and VI than MLVA. The combination of PFGE and MLVA data allowed for improved subtype discrimination and enabled the identification of recently disseminated clones. Hence, MLVA can be used in combination with PFGE to effectively accelerate the molecular epidemiologic investigation of Salmonella.

Salmonella Dublin: The impact of infection and means of on farm control

Salmonella Dublin is recognised as the cattle adapted Salmonella serovar. It currently represents the predominant isolate recovered in UK bovine salmonellosis cases recorded by the AHVLA. It can be transmitted in milk, faeces and vaginal fluids, with infection seen in all ages of cattle. The clinical signs recorded include dysentery, malaise and abortion. Spread of the infection may be indirect such as with equipment or vectors, but also by carrier animals which excrete bacteria at times of stress, principally calving. This paper outlines an outbreak of infection in a closed dairy herd and considers the potential measures available for control and monitoring of the disease.

In this issue - October 2011

AVA Policies · Unilateral uterine torsion in a bitch · Q fever in dogs in Townsville · Purchase price and racing performance of Thoroughbred yearlings · Review of genetic neurological defects in cattle · Bovine salmonellosis and antibiotic sensitivity · Chlamydial load and infectious disease in koalas · History of endemic disease regulation in Australia

Beta-lactam antibiotics prevent Salmonella-mediated bovine encephalopathy regardless of the β-lactam resistance status of the bacteria

This study assessed the capacity of β-lactam antibiotics to prevent salmonella-mediated encephalopathy in calves given the putative neuroprotective effects of these drugs of increasing glutamate export from the brain. Both ampicillin and ceftiofur prevented the development of encephalopathy despite resistance of the inoculated Salmonella enterica serovar Saint-Paul isolate to both drugs. A glutamate receptor antagonist also prevented this salmonella-mediated encephalopathy. Glutamate exporters were hyper-expressed in the presence of β-lactam antibiotics while a glutamate export inhibitor obviated the effects of these antibiotics, demonstrating a neuroprotective effect through glutamate export from the brain. The findings indicate that β-lactam antibiotics remain an important treatment option for this atypical form of bovine salmonellosis.

ESTUDO COMPARATIVO DA INFECÇÃO EXPERIMENTAL DE BEZERROS COM SALMONELLA DUBLIN E SALMONELLA TYPHIMURIUM

A COMPARATIVE STUDY OF EXPERIMENTAL SALMONELLA DUBLIN AND SALMONELLA TYPHIMURIUM INFECTIONS IN NEWBORN CALVES Salmonellosis is a disease that can affect domestic animals and humans, and its clinical signs can vary extensively. Although cattle may be infected with many different serotypes, bovine salmonellosis is caused mainly by two of them: Salmonella Dublin and Salmonella Typhimurium. Thus, to evaluate the effects of experimental infection of newborn calves, a total of twelve 10 to 15-day-old male Holstein calves were randomly allotted to one of the following groups: those infected with 108 CFU of Salmonella Dublin (Group 1); and those infected with 109 CFU of Salmonella Typhimurium (Group 2). All animals were submitted to physical examination just before inoculation and every 24 hours for six days after experimental infection. Rectal swabs and blood samples were collected to isolate Salmonella, count blood cells, and determine glucose, fibrinogen, pH, sodium, and chloride levels. Clinical evaluation of experimental S. Typhimurium infection in calves revealed mild enteritis, whereas experimental S. Dublin infection resulted in a severe systemic disease, characterized by acute enteritis, respiratory signs and higher mortality rates. Biochemical findings included increase in fibrinogen concentrations and white blood cell counts, and decrease in glucose, pH, sodium, and chloride values.

Experimental reproduction of bovine Salmonella encephalopathy using a norepinephrine-based stress model

Neurological disease represents a sporadic but serious manifestation of bovine salmonellosis that is thought to be related to systemic infection. Salmonella enterica serovar Dublin ( S. Dublin) is the serovar most associated with systemic infection in cattle, although reports of neurological disease associated with S. Dublin or any other serovar are rare and usually anecdotal. This study reports the involvement of three strains of S. enterica, serovars Saintpaul, Montevideo, and Enteritidis, in Salmonella encephalopathies. Encephalopathies were reproduced in calves using a norepinephrine-based stress model. Neurological signs were not observed in calves infected with control strains of S. enterica, including S. Dublin, or in calves infected with clinical strains in the absence of norepinephrine. Therefore, norepinephrine may play a role in Salmonella encephalopathies.

Class 1 integrons in Dutch Salmonella enterica serovar Dublin isolates from clinical cases of bovine salmonellosis

Fifty-nine Salmonella enterica serovar Dublin ( Salmonella Dublin) isolates from clinical cases of bovine salmonellosis between 1993 and 2004 were tested for their susceptibility to 15 antimicrobial agents and the presence of class 1 integrons. Integrons were further analyzed by conserved segment PCR-RFLP. DNA sequencing was used to identify the inserted gene cassette. Twelve (20.3%) isolates were multidrug-resistant. A combination of resistance against chloramphenicol, streptomycin and sulphonamides was the most common phenotype observed. Multidrug-resistance (MDR) was found to be strongly associated with the presence of integrons, since a class 1 integron with the aadA1 gene cassette encoding resistance to streptomycin and spectinomycin was found in all 12 multidrug-resistant isolates. The presence of the aadA1 gene in Salmonella Dublin has not been reported before. None of the integron carrying Salmonella Dublin isolates could transfer its antimicrobial resistance to E. coli K12 by conjugation. Analysis of plasmid profiles and pulsed field gel electrophoresis (PFGE) patterns showed at least some clonality among the Salmonella Dublin isolates, but 11 different types could be distinguished based on both XbaI and BlnI-PFGE patterns. Thus, the Dutch Salmonella Dublin strains were closely related but not clonal.

Development of Performance Indicators for the Bovine Clinical Salmonellosis Surveillance Network in France

Performance indicators are variables used to calculate on a continuous basis the operational level of a surveillance network's priority activities. A 10-step process was developed to enable network coordinators to identify specific performance indicators to help them monitor their networks. The methodology was based on a listing of surveillance activities, the definition and choice of network's global priority objectives, the construction of performance indicators and monitoring tables and the implementation of the system within the network. This process was implemented for the bovine clinical digestive salmonellosis surveillance network in France (RESSAB). The process produced a list of 26 activities synthesized into 15 global objectives, from which 12 were retained as priority objectives. This made it possible to develop 12 performance indicators. Indicators retrospectively calculated for the year 2003 indicated that RESSAB was operating according to the objectives set by the network's stakeholders and its financial supporter. The methodology was implemented successfully and was not very time consuming (12 person-days) or expensive. The decision makers and actors in the network quickly appropriated the system. The methodology can thus be considered validated through this example. Nevertheless, the risks inherent in the use of performance indicators must be addressed by ensuring the relevance of the selected indicators through external assessment and by prioritizing an internal and participatory approach to avoid a misuse of the performance indicators. In addition, considering that performance indicators address only the operation of the network, relevance of surveillance procedure should be addressed by external evaluation.

Owner-reported Incidence of Clinical Salmonellosis in Northeastern Dairy Herds

Bovine salmonellosis is important because of clinical effects and zoonotic potential. Our objectives were to determine the frequency of owner-reported salmonellosis in northeastern US dairy herds and to examine the relationship of salmonellosis with herd size and housing type.

Analysis of Salmonella enterica serotype-host specificity in calves: avirulence of S. enterica serotype gallinarum correlates with bacterial dissemination from mesenteric lymph nodes and persistence in vivo.

Host and bacterial factors that determine whether Salmonella serotypes remain restricted to the gastrointestinal tract or penetrate beyond the mucosa and cause systemic disease remain largely undefined. Here, factors influencing Salmonella host specificity in calves were assessed by characterizing the pathogenesis of different serotypes. Salmonella enterica serotype Dublin was highly virulent intravenously, whereas S. enterica serotype Choleraesuis was moderately virulent. Both serotypes were virulent in calves infected orally. In contrast, S. enterica serotypes Gallinarum and Abortusovis were avirulent by either route. Serotypes Dublin, Gallinarum, and Abortusovis colonized the intestinal tract 24 h after oral inoculation, yet only serotype Dublin was consistently recovered from systemic tissues. Serotypes Dublin and Gallinarum invaded bovine intestines in greater numbers and induced greater enteropathogenic responses than serotypes Choleraesuis and Abortusovis. However, only serotype Dublin was able to persist within the intestinal mucosa, and use of a novel cannulation model demonstrated that serotype Dublin was able to pass through the mesenteric lymph nodes in greater numbers than serotype Gallinarum. Together, these results suggest that initial interactions with the intestinal mucosa do not correlate with host specificity, although persistence within tissues and translocation via efferent lymphatics appear to be crucial for the induction of bovine salmonellosis.

Inflammatory Cytokines and Antigen-Responsive Mononuclear Cells in Peripheral Blood of Cattle Infected with Salmonella Takoradi.

To determine the immunological response in lactating dairy cows infected with Salmonella (S.) Takoradi, the relationships among distributions of peripheral blood mononuclear cell (PBMC) subpopulations, endotoxin concentrations and dynamics of inflammatory cytokines in blood were investigated. The ratio of CD4+ T cells to CD8+ T cells was significantly lower in the affected cattle than in the control cattle (p<0.05) to decrease in the number of CD4+ T cells in the infected cattle. In contrast, the numbers of gammadeltaT cells, MHC class II-positive cells were significantly higher in the affected cattle than in the control cattle (p<0.01 respectively). Endotoxemia was found in all but one of the affected cattle. Serum IL-1 and IL-6 bioactivities were significantly higher in the affected cattle than in the control cattle (IL-1, p<0.05; IL-6. p<0.01). Serum TNF-alpha activities and levels were not detected in the control and affected cattle. The activities of proinflammatory cytokines determined by the bioassay are important to the relationships between concentration of endotoxin, cytokines and clinical signs. such as leukocytosis, leukopenia, fever or bacterial shedding. Serum IL-2 levels were lower in the affected cattle than in the control cattle. Serum IFN-y was not detected in the affected cattle except one. These results by the ELISA seemed to reflect the condition of subpopulation in the PBMCs from the shedding cattle. The present results suggest that cellular immunity is suppressed while the humoral immunity is activated in acute bovine salmonellosis.