Assessment of three indigenous South African herbivores as potential reservoirs and vectors of antibiotic-resistant <Emphasis Type="Italic">Escherichia coli</Emphasis>

Due to limited data available on the presence of antibiotic-resistant (ABR) bacteria in faeces of wild herbivores in South Africa, this study analysed resistance patterns for Escherichia coli isolates from wildebeest, zebra and giraffe in addition to pet and farm pig faeces. Total and faecal coliforms and E. coli were quantified in faecal matter using a most probable number (MPN) guideline procedure. Antibiotic resistance profiles against 12 selected antibiotics representing seven classes were determined for 30 randomly selected E. coli isolates from each animal using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disk diffusion procedure. While log₁₀ MPN values per gram of animal faeces for total/faecal coliforms ranged from 4.51/4.11 to 5.70/5.50, the E. coli MPN values were in a range of 3.43–5.14. The proportion of ABR E. coli isolates ranged from 43% (giraffe) to 93% (zebra). About 47% of E. coli isolates from zebra faeces were categorized as multidrug-resistant (MDR), while for wildebeest and giraffe, no MDR isolates were detected. In comparison, 10% of E. coli isolates from pet pig and about 7% from farm pig faeces were categorized as MDR. Although most MDR isolates were resistant to at least one β-lactam antibiotic, only one MDR isolate from farm pig faeces was resistant to both norfloxacin and ciprofloxacin, the two fluoroquinolones tested. However, no resistance was detected to the tested carbapenems and tigecycline. The results of this study indicate that indigenous South African herbivores may serve as potential reservoirs and vectors for the dissemination of ABR E. coli strains.     

Biofilm production and other virulence factors in <Emphasis Type="Italic">Streptococcus</Emphasis> spp<Emphasis Type="Italic">.</Emphasis> isolated from clinical cases of bovine mastitis in Poland

Background

Mastitis is a common disease in dairy cattle throughout the world and causes considerable economic losses each year. An important aetiological agent of this disease is bacteria of the genus Streptococcus; hence, exploring the mechanisms of virulence in these bacteria is an extremely important step for the development of effective prevention programmes. The purpose of our study was to determine the ability to produce biofilm and the occurrence of selected invasiveness factors among bacteria of the genus Streptococcus isolated from cattle with the clinical form of mastitis in northeastern Poland.

Results

Most of the isolates analysed demonstrated an ability to produce biofilm (over 70%). Virulence genes were searched for in the three most common streptococci in our experiment: S. agalactiae, S. uberis and S. dysgalactiae. For S. agalactiae, only four genes were confirmed: rib (33%), cylE (78%), bca (37%), and cfb (100%). The genes pavA, scpB, bac and lmb were not present in any of the tested strains. The dominant serotypes of the species were Ia (n?=?8) and II (n?=?8), in addition to some strains that were not classified in any of the groups (n?=?6). Out of the eight selected genes for S. uberis (sua, pauA/skc, gapC, cfu, lbp, hasA, hasB, hasC), only one was not found (lbp). Finally, two genes were chosen for S. dysgalactiae (eno and napr), and their presence was confirmed in 76% and 86% of the strains, respectively.

Conclusions

The experiment showed that strains of Streptococcus spp. isolated from dairy cattle with clinical cases of mastitis in the northeastern part of Poland possess several invasiveness factors that can substantially affect the course of the disease, and this should be considered when developing targeted prevention programmes.

     

Genome-wide analysis of across herd <Emphasis Type="Italic">F</Emphasis> <Subscript>st</Subscript> Heterogeneity in holsteinized cattle

To form a reference population necessary for genomic selection of dairy cattle, it is important to acquire information on the genetic diversity of the base population. Our report is the first among the studies on breeding of farm animals to implement Wright’s F-statistics for this purpose. Genotyping of animals was performed using BovineSNP50 chip. In total, we genotyped 499 heifers from 13 breeding farms in the Leningrad region. We calculated Weir and Cockerham’s F_st estimate for all pairwise combinations of herds from breeding farms and the values obtained were in the range of 0.016–0.115 with the mean of 0.076 ± 0.002. Theoretical F_st values for the same pairwise combinations of herds were calculated using the ADMIXTURE program. These values were significantly (P < 0.05) higher than Weir and Cockerham’s F_st estimates and fell in the range of 0.063–0.136 with the mean of 0.100 ± 0.001. We discuss the reasons for this discrepancy between the two sets of F_st data. The obtained F_st values were used to identify reliable molecular-genetical differences between the herds. The ADMIXTURE program breaks the pool of 476 heifers into 16 subpopulations, the number of which is close to the number of herds used in the experiment. Results of the comparison between F_st values obtained using SNP markers with published data obtained on microsatellites are in support of the common opinion that microsatellite analysis results in underestimation of F_st values. On the whole, the obtained across-herd F_st values are in the range Fst data reported for cattle breeds. Results of comparison of F_st values with the data on the origin of bulls imported from different countries lead to the conclusion on the expediency of the use of F_st data to assess heterogeneity of the herds. Thus, we have demonstrated that use of F_st data provides the means to assess genetic diversity of cattle herds and is a necessary step in the formation of a reference population for dairy cattle.     

Taxonomic composition of bacteria associated with cultivated mollusks <Emphasis Type="Italic">Crassostrea lugubris</Emphasis> and <Emphasis Type="Italic">Perna viridis</Emphasis> and with the water of the Gulf of Nha Trang lagoon,Vietnam

One hundred and four strains of heterotrophic bacteria have been isolated and characterized from two species of bivalve mollusks cultivated in the Gulf of Nha Trang (Vietnam) and from the water of a mariculture farm. The isolates have been identified on the basis of morphological, physiological, biochemical, and chemotaxonomic properties, as well as by the content of G+C bases in DNA. In the microflora of mollusks, Vibrio alginolyticus was predominant; the pathogenic species V. harveyi and V. splendidus were found as well. Staphylococci and bacilli occupied the second place in abundance after vibrios. In addition, coryneforms and enterobacteria, as well as Pseudomonas spp. and Pseudoalteromonas spp., were revealed. The composition of the water microflora was more diverse as compared with the microflora of mollusks. In the water, Bacillus spp., Vibrio spp., and Pseudomonas spp. were predominant. Brevibacterium spp. and other coryneform bacteria, as well as enterobacteria, occurred in significant amounts. In addition, Pseudoalteromonas spp., Marinococcus sp., Halobacillus sp., Shewanella sp., Sulfitobacter sp., and bacteria of the CFB cluster were noticed. The presence of pathogenic and conditionally pathogenic bacterial species in the water and mollusks is probably the reason for the high death rate of cultivated animals at the mariculture farm.     

Clinical relevance of infections with zoonotic and human oral species of <Emphasis Type="Italic">Campylobacter</Emphasis>

Genus Campylobacter has been recognized as a causative bacterial agent of animal and human diseases. Human Campylobacter infections have caused more concern. Campylobacters can be classified into two groups in terms of their original host: zoonotic and human oral species. The major zoonotic species are Campylobacter jejuni and Campylobacter coli, which mostly reside in the intestines of avian species and are transmitted to humans via consumption of contaminated poultry products, thus causing human gastroenteritis and other diseases as sequelae. The other campylobacters, human oral species, include C. concisus, C. showae, C. gracilis, C. ureolyticus, C. curvus, and C. rectus. These species are isolated from the oral cavity, natural colonization site, but have potential clinical relevance in the periodontal region to varying extent. Two species, C. jejuni and C. coli, are believed to be mainly associated with intestinal diseases, but recent studies suggested that oral Campylobacter species also play a significant role in intestinal diseases. This review offers an outline of the two Campylobacter groups (zoonotic and human oral), their virulence traits, and the associated illnesses including gastroenteritis.     

Increased intracellular calcium level and impaired nutrient absorption are important pathogenicity traits in the chicken intestinal epithelium during <Emphasis Type="Italic">Campylobacter jejuni</Emphasis> colonization

Although a high number of chickens carry Campylobacter jejuni, the mechanistic action of colonization in the intestine is still poorly understood. The current study was therefore designed to investigate the effects of C. jejuni on glucose uptake, amino acids availability in digesta, and intracellular calcium [Ca²⁺]_i signaling in the intestines of broiler chickens. For this, we compared: control birds (n?=?60) and C. jejuni-infected birds (n?=?60; infected orally with 1?×?10⁸ CFU of C. jejuni NCTC 12744 at 14 days of age). Our results showed that glucose uptake was reduced due to C. jejuni infection in isolated jejunal, but not in cecal mucosa at 14 days postinfection (dpi). The decrease in intestinal glucose absorption coincided with a decrease in body weight gain during the 2-week post-infectious period. A reduction in the amount of the amino acids (serine, proline, valine, leucine, phenylalanine, arginine, histidine, and lysine) in ileal digesta of the infected birds at 2 and/or 7 dpi was found, indicating that Campylobacter utilizes amino acids as a carbon source for their multiplication. Applying the cell-permeable Ca²⁺ indicator Fluo-4 and two-photon microscopy, we revealed that [Ca²⁺]_i was increased in the jejunal and cecal mucosa of infected birds. The muscarinic agonist carbachol induced an increase in [Ca²⁺]_i in jejunum and cecum mucosa of control chickens, a response absent in the mucosa of infected chickens, demonstrating that the modulation of [Ca²⁺]_i by Campylobacter might be involved in facilitating the necessary cytoskeletal rearrangements that occur during the bacterial invasion of epithelial cells. In conclusion, this study demonstrates the multifaceted interactions of C. jejuni with the gastrointestinal mucosa of broiler chickens. For the first time, it could be shown that a Campylobacter infection could interfere with intracellular Ca²⁺ signaling and nutrient absorption in the small intestine with consequences on intestinal function, performance, and Campylobacter colonization. Altogether, these findings indicate that Campylobacter is not entirely a commensal and can be recognized as an important factor contributing to an impaired chicken gut health.     

The protective effect of a novel antioxidant gene from <Emphasis Type="Italic">Mycobacterium avium</Emphasis> against nitrosative and oxidative stress in <Emphasis Type="Italic">E. coli</Emphasis>

The production of reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI) is an important host defense mechanism in response to infection by Mycobacterium tuberculosis. A variety of genes have been implicated in resistance to ROI and RNI, including noxR1. However, studies in Mycobacterium avium, an important pathogen among nontuberculous mycobacteria, are limited. We aim to investigate the role of a novel gene cloned from M. avium with high similarity to noxR1, noA, in resistance against RNI and ROI in M. tuberculosis. After subcloning noA into vector for expression in E. coli, we performed survival rate analysis in the bacteria transformed with noA (pET-noA) and without noA (pET-his) after exposure to nitrosative stresses by S-nitrosoglutathione (GSNO) and sodium nitrite, and oxidative stresses by H₂O₂. Compared with pET-his, the survival rate of pET-noA was 1 log₁₀-fold higher after exposure to GSNO and sodium nitrite. We observed 1 log₁₀-fold, 2 log₁₀-fold and 3 log₁₀-fold higher survival rate in pET-noA than pET-his after exposure to H₂O₂ for 3, 6 and 9 h, respectively. With the combined treatment of H₂O₂ and GSNO, we found more than 2 log₁₀-fold increase in survival rate in pET-noA comparing with pET-his, suggesting a possible synergistic effect. In summary, noA gene cloned from M. avium has been shown to protect E. coli from both RNI and ROI.     

Assessment of the antifungal activity of <Emphasis Type="Italic">Lactobacillus</Emphasis> and <Emphasis Type="Italic">Pediococcus</Emphasis> spp. for use as bioprotective cultures in dairy products

Fungi are commonly involved in dairy product spoilage and the use of bioprotective cultures can be a complementary approach to reduce food waste and economic losses. In this study, the antifungal activity of 89 Lactobacillus and 23 Pediococcus spp. isolates against three spoilage species, e.g., Yarrowia lipolytica, Rhodotorula mucilaginosa and Penicillium brevicompactum, was first evaluated in milk agar. None of the tested pediococci showed antifungal activity while 3, 23 and 43 lactobacilli isolates showed strong antifungal activity or total inhibition against Y. lipolytica, R. mucilaginosa and P. brevicompactum, respectively. Then, the three most promising strains, Lactobacillus paracasei SYR90, Lactobacillus plantarum O_VI9 and Lactobacillus rhamnosus BIO_III28 at initial concentrations of 10⁵ and 10⁷ CFU/ml were tested as bioprotective cultures against the same fungal targets in a yogurt model during a 5-week storage period at 10 °C. While limited effects were observed at 10⁵ CFU/ml inoculum level, L. paracasei SYR90 and L. rhamnosus BIO_III28 at 10⁷ CFU/ml respectively retarded the growth of R. mucilaginosa and P. brevicompactum as compared to a control without selected cultures. In contrast, growth of Y. lipolytica was only slightly affected. In conclusion, these selected strains may be good candidates for bioprotection of fermented dairy products.     

Isolation of <Emphasis Type="Italic">Campylobacter</Emphasis> spp. from Three Species of Antarctic Penguins in Different Geographic Locations

The presence of Campylobacter species was studied in three Antarctic penguin species, Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarctica) and gentoo (Pygoscelis papua). A total of 390 penguins were captured in 12 different rookeries along the Antarctic Peninsula with differences in the amount of human visitation: six colonies were highly visited [Stranger Point, King George Island (P. papua and P. adeliae); Hannah Point, Livingston Island (P. papua and P. antarctica); Deception Island (P. antarctica); and Paradise Bay, Antarctic Peninsula (P. papua)], and six colonies were rarely visited [Devil’s Point, Byers Peninsula, Livingston Island (P. papua); Cierva Cove, Antarctic Peninsula (P. papua); Rongé Island (P. papua and P. antarctica); Yalour Island (P. adeliae); and Avian Island (P. adeliae)]. A total of 23 strains were isolated from penguins from nine different rookeries. Campylobacter lari subsp. lari was isolated from eight samples (seven from P. papua and one from P. adeliae); C. lari subsp. concheus from 13 (ten from P. adeliae and three from P. antarctica) and C. volucris from two samples (both from P. papua). We did not find any significant differences in the prevalence of Campylobacter spp. between the populations in highly and rarely visited areas. This is the first report of C. lari subsp. concheus and C. volucris isolation from penguins in the Antarctic region.     

Further characterization and independent validation of a DNA aptamer-quantum dot-based magnetic sandwich assay for <Emphasis Type="Italic">Campylobacter</Emphasis>

Previously reported DNA aptamers developed against surface proteins extracted from Campylobacter jejuni were further characterized by aptamer-based Western blotting and shown to bind epitopes on proteins weighing ~16 and 60 kD from reduced C. jejuni and Campylobacter coli lysates. Proteins of these approximate weights have also been identified in traditional antibody-based Western blots of Campylobacter spp. Specificity of the capture and reporter aptamers from the previous report was further validated by aptamer-based ELISA-like (ELASA) colorimetric microplate assay. Finally, the limit of detection of the previously reported plastic-adherent aptamer-magnetic bead and aptamer-quantum dot sandwich assay (PASA) was validated by an independent food safety testing laboratory to lie between 5 and 10 C. jejuni cells per milliliter in phosphate buffered saline and repeatedly frozen and thawed chicken rinsate. Such ultrasensitive and rapid (30 min) aptamer-based assays could provide alternative or additional screening tools to enhance food safety testing for Campylobacter and other foodborne pathogens.     

Effect of <Emphasis Type="Italic">UCP2</Emphasis> and <Emphasis Type="Italic">UCP3</Emphasis> Genes Polymorphisms on Functional Traits in Dairy Cattle

The aim of this study was to investigate associations between genotypes of UCP2 and UCP3 genes, milk, and reproduction traits in dairy cattle. The study included two herds: Jersey cows and Polish Holstein-Friesian (Red and White strain) cows. All cows were genotyped using the PCR-RFLP method and allele frequencies were determined. Statistical analysis showed a significant association between polymorphism in the UCP3 gene and the milk yield and fat content of milk (P ≤ 0.05, P ≤ 0.01) and between the UCP2 gene and the calving interval (P ≤ 0.05). Information contained in this study may be useful in further analysis to define the role of analysed genes in relation to functional traits in dairy cattle, nevertheless, the obtained results should be verified by conducting research on a larger group of animals and various cattle breeds.     

Genome-wide association study of <Emphasis Type="Italic">Mycobacterium avium</Emphasis> subspecies <Emphasis Type="Italic">Paratuberculosis</Emphasis> infection in Chinese Holstein

Background

Paratuberculosis is a contagious, chronic and enteric disease in ruminants, which is caused by Mycobacterium avium subspecies paratuberculosis (MAP) infection, resulting in enormous economic losses worldwide. There is currently no effective cure for MAP infection or a vaccine, it is thus important to explore the genetic variants that contribute to host susceptibility to infection by MAP, which may provide a better understanding of the mechanisms of paratuberculosis and benefit animal genetic improvement. Herein we performed a genome-wide association study (GWAS) to identify genomic regions and candidate genes associated with susceptibility to MAP infection in dairy cattle.

Results

Using Illumina Bovine 50?K (54,609 SNPs) and GeneSeek HD (138,893 SNPs) chips, two analytical approaches were performed, GRAMMAR-GC and ROADTRIPS in 937 Chinese Holstein cows, among which individuals genotyped by the 50?K chip were imputed to HD SNPs with Beagle software. Consequently, 15 and 11 significant SNPs (P?<?5?×?10^??5) were identified with GRAMMAR-GC and ROADTDRIPS, respectively. A total of 10 functional genes were in proximity to (i.e., within 1?Mb) these SNPs, including IL4, IL5, IL13, IRF1, MyD88, PACSIN1, DEF6, TDP2, ZAP70 and CSF2. Functional enrichment analysis showed that these genes were involved in immune related pathways, such as interleukin, T cell receptor signaling pathways and inflammatory bowel disease (IBD), implying their potential associations with susceptibility to MAP infection. In addition, by examining the publicly available cattle QTLdb, a previous QTL for MAP was found to be overlapped with one of regions detected currently at 32.5?Mb on BTA23, where the TDP2 gene was anchored.

Conclusions

In conclusion, we identified 26 SNPs located on 15 chromosomes in the Chinese Holstein population using two GWAS strategies with high density SNPs. Integrated analysis of GWAS, biological functions and the reported QTL information helps to detect positional candidate genes and the identification of regions associated with susceptibility to MAP traits in dairy cattle.

     

Artificial induction of genetic competence in <Emphasis Type="Italic">Bacillus amyloliquefaciens</Emphasis> isolates

Objectives

To induce natural genetic competence in Bacillus amyloliquefaciens isolates through overexpression of the master regulator, ComK, from B. subtilis (ComK _Bsu ).

Results

Plasmid pUBXC carrying the xylose-inducible comK expression cassette was constructed using plasmid pUB110 as a backbone. Plasmid pUBXC could be transferred from B. subtilis to B. amyloliquefaciens through plasmid pLS20-mediated biparental conjugation. After being induced by xylose, four B. amyloliquefaciens strains harbouring plasmid pUBXC developed genetic competence. Under optimal conditions, the transformation efficiencies of plasmid DNA ranged from 129 ± 20.6 to 1.7 ± 0.1 × 10⁵ cfu (colony-forming units) per μg DNA, and the transformation efficiencies of PCR-assembled deletion constructs ranged from 3.2 ± 0.76 to 3.5 ± 0.42 × 10⁴ cfu per μg DNA in the four tested strains.

Conclusion

Artificial induction of genetic competence through overexpressing ComK _Bsu in B. amyloliquefaciens completed the tasks of replicative plasmid delivery and gene knockout via direct transformation of PCR-generated deletion cassettes.

     

Construction of a thermo-sensitive pRI857 vector for efficient DNA capturing in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Objectives

To establish a positive cloning system with a zero background for high-throughput DNA cloning purpose.

Results

The cloning vector, pRI857, and the genomic-library construction vector, pRI857-BAC, were constructed based on the mechanism of expression of the thermo-sensitive cI857 repressor gene that can stringently repress the P_R promoter and kanamycin resistance gene (P_R-kan ^R ) at 30 °C, but have no effect on P_R-kan ^R gene at 37 °C or at higher temperatures. When the pRI857 vectors were transformed into E. coli with or without a target foreign DNA fragment inserted at the BfrBI site of the cI857 gene, only colonies with the foreign DNA fragment survive. We extended this method to construct a pRI857-BAC vector for genomic library cloning which displays an efficiency of ~10⁷ cfu per µg of genomic DNA, with no empty vectors detected.

Conclusions

Cloning by indirect activation of resistance marker gene represents a novel DNA-capturing system, which can be widely applied for high-throughput DNA cloning.

     

Detection of Cryptic <Emphasis Type="Italic">Candida</Emphasis> Species Recognized as Human Pathogens Through Molecular Biology Techniques

Purpose of Review

The aim of this review is to evaluate these molecular-based methods able to identify pathogenic cryptic Candida spp. focusing on those that demonstrated to be useful in clinical laboratory settings.

Recent Findings

It is long known that some Candida spp. are genetically heterogeneous. Firstly, individual species were divided into groups based on differences on the sequence of some genes. Later, those groups were designated as cryptic species and defined as phenotypically indistinguishable species that are only identified by their DNA sequences. Many common Candida spp. are now considered complexes formed by several cryptic species. Some of them have been recognized as human pathogens. The identification of these species is problematic but necessary since they have different host range, infection sites, infection severity, and antifungal susceptibility. Several independent DNA markers were proposed as tools for the differentiation of highly related species. We will concentrate on the three species complexes most frequently associated with human infections including Candida albicans, C. glabrata, and C. parapsilosis complexes and a fourth group of less common but multiresistant species including C. haeumulonii complex and C. auris.

Summary

We review the clinically useful molecular tools able to differentiate the cryptic species of C. albicans, C. glabrata, and C. parapsilosis complexes and designated to uncover emerging multiresistant species.

     

Dairy propionibacteria as direct-fed microbials: in vitro effect on acid metabolism of <Emphasis Type="Italic">Streptococcus bovis</Emphasis> and <Emphasis Type="Italic">Megasphaera elsdenii</Emphasis>

Ruminal acidosis caused by accumulation of lactic acid, a decrease of pH in the rumen and subsequent imbalance of the rumen fermentation process, affects the health and productivity of dairy cows and beef cattle. Direct-fed microbials have potential for use in the control and prevention of ruminal acidosis. This study investigated the interaction between five strains of dairy propionibacteria, Megasphaera elsdenii and Streptococcus bovis in various co-culture combinations in a simulated rumen environment comprising unmodified rumen digesta supplemented with excess glucose. While suppression of lactic acid accumulation by both the dairy propionibacteria and M. elsdenii in the presence of S. bovis in the simulated rumen conditions was evident, propionibacteria were found to be more effective than M. elsdenii in controlling lactic acid levels.     

<Emphasis Type="Italic">Aeromonas</Emphasis> and <Emphasis Type="Italic">Plesiomonas</Emphasis> species from scarlet ibis (<Emphasis Type="Italic">Eudocimus ruber</Emphasis>) and their environment: monitoring antimicrobial susceptibility and virulence

The present study aimed at evaluating the role of captive scarlet ibises (Eudocimus ruber) and their environment as reservoirs of Aeromonas spp. and Plesiomonas spp., and analyzing the in vitro antimicrobial susceptibility and virulence of the recovered bacterial isolates. Thus, non-lactose and weak-lactose fermenting, oxidase positive Gram-negative bacilli were recovered from cloacal samples (n = 30) of scarlet ibises kept in a conservational facility and from water samples (n = 30) from their environment. Then, the antimicrobial susceptibility, hemolytic activity and biofilm production of the recovered Aeromonas spp. and Plesiomonas shigelloides strains were assessed. In addition, the virulence-associated genes of Aeromonas spp. were detected. Ten Aeromonas veronii bv. sobria, 2 Aeromonas hydrophila complex and 10 P. shigelloides were recovered. Intermediate susceptibility to piperacillin-tazobactam and cefepime was observed in 2 Aeromonas spp. and 1 P. shigelloides, respectively, and resistance to gentamicin was observed in 4 P. shigelloides. The automated susceptibility analysis revealed resistance to piperacillin-tazobactam and meropenem among Aeromonas spp. and intermediate susceptibility to gentamicin among P. shigelloides. All Aeromonas isolates presented hemolytic activity, while 3 P. shigelloides were non-hemolytic. All Aeromonas spp. and 3/10 P. shigelloides were biofilm-producers, at 28 °C, while 10 Aeromonas spp. and 6/10 P. shigelloides produced biofilms, at 37 °C. The most prevalent virulence genes of Aeromonas spp. were asa1 and ascV. Scarlet ibises and their environment harbour potentially pathogenic bacteria, thus requiring monitoring and measures to prevent contamination of humans and other animals.     

Risk factors for <Emphasis Type="Italic">Coxiella burnetii</Emphasis> antibodies in bulk tank milk from Danish dairy herds

The aim was to identify risk factors associated with Coxiella burnetii antibody positivity in bulk tank milk (BTM) samples from 100 randomly selected Danish dairy cattle herds. Antibody levels were measured by an enzyme-linked immuno-sorbent assay. Before testing the herds, the farm managers were interviewed about hired labour, biosecurity, housing and herd health during the 12 months prior to the study. Variables considered important for C. burnetii antibody positivity in multivariable logistic regression analysis included the sharing of machines between farms (OR?=?3.6), human contacts (OR?=?4.2), artificial insemination by other people than artificial insemination technicians (OR?=?7.7), routine herd health contract with the veterinarian (OR?=?4.3) and hygiene precautions taken by veterinarians (OR?=?5). In addition, herd size, hired labour, trading of cattle between farms, quarantine and use of calving and disease pens also showed significant association in univariable analysis. This study demonstrates that strict biosecurity is important for the prevention of infections with C. burnetii.     

Antibiotic-Resistant Genes and Pathogens Shed by Wild Deer Correlate with Land Application of Residuals

The purpose of this study was to investigate genetic biomarkers of zoonotic enteric pathogens and antibiotic-resistant genes (ARGs) in the feces of white-tailed deer (Odocoileus virginianus) as related to proximity of deer to land that receives livestock manure or human waste biosolid fertilizers. Deer feces were collected in the St. Lawrence River Valley and Adirondack State Park of New York. Campylobacter spp. 16S rDNA was detected in 12 of 232 fecal samples (8 of 33 sites). Salmonellae were cultivated from 2 of 182 fecal samples (2 of 29 sites). Genetic virulence markers for Shiga-like toxin I (stx₁) and enterohemolysin (hylA) were each detected in one isolate of Escherichia coli; E. coli O157 was not detected in any of 295 fecal samples. ARGs detected in deer feces included ermB (erythromycin-resistant gene; 9 of 295 fecal samples, 5 of 38 sites), vanA (vancomycin-resistant gene; 93 of 284 samples, 33 of 38 sites), tetQ (tetracycline-resistant gene; 93 of 295 samples, 25 of 38 sites), and sul(I) (sulfonamide-resistant gene; 113 of 292 samples, 28 of 38 sites). Genetic markers of pathogens and ARGs in deer feces were spatially associated with collection near concentrated animal feeding operations (CAFOs; Campylobacter spp., tetQ, and ermB) and land-applied biosolids (tetQ). These results indicate that contact with human waste biosolids or animal manure may be an important method of pathogen and ARG transmission and that deer in proximity to land-applied manure and human waste biosolids pose increased risk to nearby produce and water quality.