@article{vince_lascelles_mathews_altier_roe_2008, title={Evaluation of wraps covering the distal aspect of pelvic limbs for prevention of bacterial strike-through in an ex vivo canine model}, volume={37}, ISSN={["0161-3499"]}, url={https://dx.doi.org/10.1111/j.1532-950X.2008.00395.x}, DOI={10.1111/j.1532-950X.2008.00395.x}, abstractNote={To determine differences in bacterial strike-through for materials commonly used to cover the distal aspect of the pelvic limb during operative site preparation.Randomized block design; ex vivo model.Canine cadaveric pelvic limbs (n=40).Pelvic limbs (n=40) were randomly assigned to 4 treatment groups: Group 1=Vetrap+sterile Coban; Group 2=latex glove+Vetrap+sterile Coban; Group 3=latex glove+Vetrap+sterile Coban+sterile latex glove+sterile Coban; and Group 4=latex glove+Vetrap+sterile disposable drape+sterile Coban. Limbs were contaminated with a standardized bacterial solution and routinely prepared using the assigned distal leg wrap. Bandages were fluid challenged with a saline (0.9% NaCl) solution-soaked laparotomy sponge for 30 seconds. The wrap surface was sampled for microbial culture before surgical preparation, immediately after, and 60 minutes after applying a sterile leg wrap.Bacterial growth occurred in all Group 1 cultures, 90% of Group 2 cultures, and none of the Group 3 and 4 cultures, 60 minutes after applying the sterile wrap.A distal leg wrap of Vetrap+sterile Coban is not effective in preventing bacterial strike-through.If similar results occur in the live animal, then a sterile impermeable barrier must be incorporated into the distal leg wrap to prevent bacterial strike-through.}, number={4}, journal={VETERINARY SURGERY}, author={Vince, Kent J. and Lascelles, B. Duncan X. and Mathews, Kyle G. and Altier, Craig and Roe, Simon C.}, year={2008}, month={Jun}, pages={406–411} }
 @article{huang_suyemoto_garner_cicconi_altier_2008, title={Formate acts as a diffusible signal to induce Salmonella invasion}, volume={190}, ISSN={["1098-5530"]}, DOI={10.1128/JB.00205-08}, abstractNote={ABSTRACT To infect an animal host, Salmonella enterica serovar Typhimurium must penetrate the intestinal epithelial barrier. This process of invasion requires a type III secretion system encoded within Salmonella pathogenicity island I (SPI1). We found that a mutant with deletions of the acetate kinase and phosphotransacetylase genes ( ackA-pta ) was deficient in invasion and SPI1 expression but that invasion gene expression was completely restored by supplying medium conditioned by growth of the wild-type strain, suggesting that a signal produced by the wild type, but not by the ackA-pta mutant, was required for invasion. This mutant also excreted 68-fold-less formate into the culture medium, and the addition of sodium formate to cultures restored both the expression of SPI1 and the invasion of cultured epithelial cells by the mutant. The effect of formate was pH dependent, requiring a pH below neutrality, and studies in mice showed that the distal ileum, the preferred site of Salmonella invasion in this species, had the appropriate formate concentration and pH to elicit invasion, while the cecum contained no detectable formate. Furthermore, we found that formate affected the major regulators of SPI1, hilA and hilD , but that the primary routes of formate metabolism played no role in its activity as a signal.}, number={12}, journal={JOURNAL OF BACTERIOLOGY}, author={Huang, Yanyan and Suyemoto, Mitsu and Garner, Cherilyn D. and Cicconi, Kellie M. and Altier, Craig}, year={2008}, month={Jun}, pages={4233–4241} }
 @article{lin_yan_huang_altier_li_carrasco_suyemoto_johnston_wang_wang_et al._2007, title={Design and synthesis of boronic-acid-labeled thymidine triphosphate for incorporation into DNA}, volume={35}, DOI={10.1093/nar/gkl1091}, abstractNote={The boronic acid moiety is a versatile functional group useful in carbohydrate recognition, glycoprotein pull-down, inhibition of hydrolytic enzymes and boron neutron capture therapy. The incorporation of the boronic-acid group into DNA could lead to molecules of various biological functions. We have successfully synthesized a boronic acid-labeled thymidine triphosphate (B-TTP) linked through a 14-atom tether and effectively incorporated it into DNA by enzymatic polymerization. The synthesis was achieved using the Huisgen cycloaddition as the key reaction. We have demonstrated that DNA polymerase can effectively recognize the boronic acid-labeled DNA as the template for DNA polymerization, that allows PCR amplification of boronic acid-labeled DNA. DNA polymerase recognitions of the B-TTP as a substrate and the boronic acid-labeled DNA as a template are critical issues for the development of DNA-based lectin mimics via in vitro selection.}, number={4}, journal={Nucleic Acids Research}, author={Lin, N. and Yan, J. and Huang, Z. and Altier, C. and Li, M. Y. and Carrasco, N. and Suyemoto, M. and Johnston, L. and Wang, S. M. and Wang, Q. and et al.}, year={2007}, pages={1222–1229} }
 @article{bush_poore_rogers_altier_2007, title={Effect of stacking method on Salmonella elimination from recycled poultry bedding}, volume={98}, ISSN={["0960-8524"]}, DOI={10.1016/j.biortech.2006.02.017}, abstractNote={Recycled poultry bedding (RPB) is a protein and mineral supplement for cattle. Concerns regarding this product have arisen because of the perceived risk of transmitting potentially pathogenic organisms to cattle. This study's primary objective was to assess survival of Salmonella in RPB stacked to a recommended height (2.13 m-DS-RPB), or a height of 0.76 m (SS-RPB). Dialysis bags containing RPB and Salmonella typhimurium were placed throughout stacks. Temperature was monitored daily using thermocouples attached to sample bags. After 21 days, sample bags were recovered. Ammonia analysis was performed from multiple sites in the stacks. Bag contents were cultured to determine viability of the salmonella inoculates. This trial demonstrated a wide variation of temperature within the stacks. Temperature near the edge of stacks changed with ambient temperature. Ammonia concentration in the RPB was highest at the top of the DS-RPB. Salmonella was eliminated in 98.7% of sites, with at least a 5-log reduction in the Salmonella organisms in sites where it was still viable.}, number={3}, journal={BIORESOURCE TECHNOLOGY}, author={Bush, Dawn J. and Poore, Matthew H. and Rogers, Glenn M. and Altier, Craig}, year={2007}, month={Feb}, pages={571–578} }
 @article{fortune_suyemoto_altier_2006, title={Identification of CsrC and characterization of its role in epithelial cell invasion in Salmonella enterica serovar Typhimurium}, volume={74}, ISSN={["1098-5522"]}, DOI={10.1128/IAI.74.1.331-339.2006}, abstractNote={ABSTRACT The csr regulatory system of Salmonella regulates the expression of the genes of Salmonella pathogenicity island 1 (SPI1) required for the invasion of epithelial cells. This system consists of the posttranscriptional regulator CsrA and an untranslated regulatory RNA, CsrB, that opposes the action of CsrA. Here we identify and characterize the role of a second regulatory RNA, CsrC, whose ortholog was discovered previously in Escherichia coli . We show that a mutant of csrC has only mild defects in invasion and the expression of SPI1 genes, as does a mutant of csrB , but that a double csrB csrC mutant is markedly deficient in these properties, suggesting that the two regulatory RNAs play redundant roles in the control of invasion. We further show that CsrC, like CsrB, is controlled by the BarA/SirA two-component regulator but that a csrB csrC mutant exhibits a loss of invasion equivalent to that of a barA or sirA mutant, indicating that much of the effect of BarA/SirA on invasion functions through its control of CsrB and CsrC. In addition to their control by BarA/SirA, each regulatory RNA is also controlled by other components of the csr system. The loss of csrB was found to increase the level of CsrC by sevenfold, while the loss of csrC increased CsrB by nearly twofold. Similarly, the overexpression of csrA increased CsrC by nearly 11-fold and CsrB by 3-fold and also significantly increased the stability of both RNAs.}, number={1}, journal={INFECTION AND IMMUNITY}, author={Fortune, DR and Suyemoto, M and Altier, C}, year={2006}, month={Jan}, pages={331–339} }
 @article{gebreyes_altier_thakur_2006, title={Molecular epidemiology and diversity of Salmonella serovar Typhimurium in pigs using phenotypic and genotypic approaches}, volume={134}, ISSN={["1469-4409"]}, DOI={10.1017/S0950268805004723}, abstractNote={SUMMARY For epidemiological investigations of the most common and non-host-adapted Salmonella serotypes, such as Typhimurium, highly discriminatory approaches are essential. In the present study, we evaluated three genotyping methods; amplified fragment length polymorphism (AFLP), pulsed-field gel electrophoresis (PFGE) and repetitive palindromic extragenic–PCR (Rep–PCR) using 40 isolates. AFLP showed the highest discriminatory index (0·939), resolution and throughput. To determine clonality of Salmonella Typhimurium isolates and epidemiological relatedness in different commercial pig production units, we employed AFLP in combination with antimicrobial resistance pattern and phage typing. Salmonella serovar Typhimurium isolates ( n =196) obtained from a longitudinal study of 18 pig farms over a 3-year period were studied. Using this approach, 16 distinct clonal types were identified. We found two common multidrug- resistant patterns including AmCmStSuTe and AmKmStSuTe. Two commonly multidrug- resistant phage types that are of known public health importance, DT104 and DT193, were also common. AFLP differentiated distinct clones within DT104, a phage type previously reported to be clonal. Fourteen of the clonal types were unique to one of the two production systems, showing diversity between independent commercial pig production systems located in the same geographical area. Clonal types obtained from nursery farms and corresponding finishing units were, however, similar.}, number={1}, journal={EPIDEMIOLOGY AND INFECTION}, author={Gebreyes, WA and Altier, C and Thakur, S}, year={2006}, month={Feb}, pages={187–198} }
 @misc{altier_2005, title={Genetic and environmental control of Salmonella invasion}, volume={43}, number={Feb-05}, journal={Journal of Microbiology}, author={Altier, C.}, year={2005}, pages={85–92} }
 @article{gebreyes_davies_turkson_morgan morrow_funk_altier_thakur_2004, title={Characterization of Antimicrobial-Resistant Phenotypes and Genotypes among Salmonella enterica Recovered from Pigs on Farms, from Transport Trucks, and from Pigs after Slaughter}, volume={67}, ISSN={0362-028X}, url={http://jfoodprotection.org/doi/abs/10.4315/0362-028X-67.4.698}, DOI={10.4315/0362-028X-67.4.698}, abstractNote={The main objectives of this study were to determine antimicrobial resistance patterns among Salmonella serotypes and to evaluate the role of transport trucks in dissemination of antimicrobial-resistant strains of Salmonella. Salmonella from groups of nursery and finishing pigs on farms, from trucks, and from pigs after slaughter were compared using serotyping, patterns of antimicrobial resistance, and pulsed-field gel electrophoresis patterns. The five farms included in the study yielded 858 isolates representing 27 Salmonella serovars. The most common resistance observed (80% of all isolates) was to tetracycline; resistance to ampicillin (42%), chloramphenicol (31%), amoxicillin/clavulanic acid (30%), and piperacillin (31%) also were common. We found a correlation between serovar and antimicrobial resistance. High correlation was found between Salmonella Typhimurium var. Copenhagen and chloramphenicol resistance (Spearman rank correlation, rho = 0.7). Multidrug resistance was observed primarily in Salmonella Typhimurium var. Copenhagen (94%) and Salmonella Typhimurium (93%) and was much less common in the other common serovars, including Salmonella Derby (7%) and Salmonella Heidelberg (8%). Of the 225 isolates exhibiting the most common pentaresistance pattern in this study, amoxicillin/clavulanic acid-ampicillin-chloramphenicol-piperacillin-tetracycline, 220 (98%) were Salmonella Typhimurium var. Copenhagen, and 86% of the isolates of this serovar had this pattern. Isolates from the trucks were similar, based on pulsed-field gel electrophoresis patterns, to those from the cecum and mesenteric lymph nodes of pigs on two of the farms, suggesting the probable infection of pigs during transport. Class I integrons were also common among various serovars.}, number={4}, journal={Journal of Food Protection}, author={Gebreyes, Wondwossen A. and Davies, Peter R. and Turkson, Paa-Kobina and Morgan Morrow, W. E. and Funk, Julie A. and Altier, Craig and Thakur, Siddhartha}, year={2004}, month={Apr}, pages={698–705} }
 @article{gebreyes_davies_turkson_morrow_funk_altier_2004, title={Salmonella enterica serovars from pigs on farms and after slaughter and validity of using bacteriologic data to define herd Salmonella status}, volume={67}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-67.4.691}, abstractNote={The primary objective of this study was to evaluate the validity of using data obtained from slaughtered pigs for farm-level epidemiologic studies of Salmonella. The study involved groups of pigs from five farms. Salmonella isolates were obtained from on-farm samples, and a total of 370 on-farm and an additional 486 isolates from samples collected after commercial slaughter were subsequently tested. Preharvest samples included feces of individual animals from defined groups of nursery and finishing pigs on commercial farms and swabs from trucks. Postslaughter samples were cecal contents and mesenteric lymph node samples. The concordance between Salmonella serovars isolated from on-farm samples and those serovars isolated after slaughter varied widely among farms. Results of paired lymph node and cecal cultures were strongly associated (odds ratio, 7.0), but the agreement between on-farm and postslaughter results at the pig level was poor (kappa = 0.34). The results support recent findings that risk of exposure to Salmonella during transport and lairage remains a concern under contemporary industry conditions. The findings further imply that slaughter plant studies based on phenotyping of Salmonella alone (such as serovars) may not reliably indicate the Salmonella status of commercial swine farms.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Gebreyes, WA and Davies, PR and Turkson, PK and Morrow, WEM and Funk, JA and Altier, C}, year={2004}, month={Apr}, pages={691–697} }
 @article{gebreyes_thakur_davies_funk_altier_2004, title={Trends in antimicrobial resistance, phage types and integrons among Salmonella serotypes from pigs, 1997-2000}, volume={53}, ISSN={["1460-2091"]}, DOI={10.1093/jac/dkh247}, abstractNote={The objectives of this study were to determine antimicrobial resistance and to identify phage types and class 1 integrons among non-typhoidal Salmonella isolates from 24 pig farms in North Carolina collected between 1997 and 2000.A total of 1314 isolates of 30 serotypes from pig faecal samples were collected and analysed over a 3 year period. The isolates were characterized using antimicrobial susceptibility testing, phage typing, PCR and DNA sequencing for class 1 integrons.A high frequency of resistance to antimicrobial agents including tetracycline (85%), ampicillin (47%), co-amoxiclav (23%) and chloramphenicol (21%) was detected. Two multidrug resistance patterns were common in Typhimurium (including variant Copenhagen): isolates with co-amoxiclav, ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and tetracycline (R-type AxACSSuT) [36%] and isolates with ampicillin, kanamycin, streptomycin, sulfamethoxazole and tetracycline (R-type AKSSuT) [45%] resistance patterns. Definitive Type 104 (DT104) was the most common (34%) among eight phage types identified. AKSSuT was found among non-DT104 phage types, particularly DT21 and DT193. Class 1 integrons were detected among various serotypes including Typhimurium, Derby, Muenchen, Worthington, Bere and Muenster. aadA was the most common resistance gene insert, and the oxa30 beta-lactamase resistance gene was also identified among serovar Muenchen.In this study, two most important multidrug resistance patterns (AxACSSuT and AKSSuT) and phage types of public health significance (DT104 and DT193) constituted two-thirds of the serotype Typhimurium isolates. The findings imply that pigs raised in the commercial production system may pose a risk in serving as reservoirs of resistant Salmonella.}, number={6}, journal={Journal of Antimicrobial Chemotherapy}, author={Gebreyes, W.A. and Thakur, S. and Davies, P.R. and Funk, J.A. and Altier, C.}, year={2004}, month={Jun}, pages={997–1003} }
 @article{lawhon_frye_suyemoto_porwollik_mcclelland_altier_2003, title={Global regulation by CsrA in Salmonella typhimurium}, volume={48}, ISSN={["1365-2958"]}, DOI={10.1046/j.1365-2958.2003.03535.x}, abstractNote={CsrA is a regulator of invasion genes in Salmonella enterica serovar Typhimurium. To investigate the wider role of CsrA in gene regulation, we compared the expression of Salmonella genes in a csrA mutant with those in the wild type using a DNA microarray. As expected, we found that expression of Salmonella pathogenicity island 1 (SPI-1) invasion genes was greatly reduced in the csrA mutant, as were genes outside the island that encode proteins translocated into eukaryotic cells by the SPI-1 type III secretion apparatus. The flagellar synthesis operons, flg and fli, were also poorly expressed, and the csrA mutant was aflagellate and non-motile. The genes of two metabolic pathways likely to be used by Salmonella in the intestinal milieu also showed reduced expression: the pdu operon for utilization of 1,2-propanediol and the eut operon for ethanolamine catabolism. Reduced expression of reporter fusions in these two operons confirmed the microarray data. Moreover, csrA was found to regulate co-ordinately the cob operon for synthesis of vitamin B12, required for the metabolism of either 1,2-propanediol or ethanolamine. Additionally, the csrA mutant poorly expressed the genes of the mal operon, required for transport and use of maltose and maltodextrins, and had reduced amounts of maltoporin, normally a dominant protein of the outer membrane. These results show that csrA controls a number of gene classes in addition to those required for invasion, some of them unique to Salmonella, and suggests a co-ordinated bacterial response to conditions that exist at the site of bacterial invasion, the intestinal tract of a host animal.}, number={6}, journal={MOLECULAR MICROBIOLOGY}, author={Lawhon, SD and Frye, JG and Suyemoto, M and Porwollik, S and McClelland, M and Altier, C}, year={2003}, month={Jun}, pages={1633–1645} }
 @article{seguin_vaden_altier_stone_levine_2003, title={Persistent urinary tract infections and reinfections in 100 dogs (1989-1999)}, volume={17}, ISSN={["0891-6640"]}, DOI={10.1892/0891-6640(2003)017<0622:PUTIAR>2.3.CO;2}, number={5}, journal={JOURNAL OF VETERINARY INTERNAL MEDICINE}, author={Seguin, MA and Vaden, SL and Altier, C and Stone, E and Levine, JF}, year={2003}, pages={622–631} }
 @article{capucille_poore_altier_rogers_2002, title={Evaluation of Salmonella shedding in cattle fed recycled poultry bedding}, volume={36}, ISBN={0524-1685}, number={1}, journal={Bovine Practitioner}, author={Capucille, D. J. and Poore, M. H. and Altier, C. and Rogers, G. M.}, year={2002}, pages={15} }
 @article{lawhon_maurer_suyemoto_altier_2002, title={Intestinal short-chain fatty acids alter Salmonella typhimurium invasion gene expression and virulence through BarA/SirA}, volume={46}, ISSN={["1365-2958"]}, DOI={10.1046/j.1365-2958.2002.03268.x}, abstractNote={Salmonella typhimurium causes enteric and systemic disease by invading the intestinal epithelium of the distal ileum, a process requiring the invasion genes of Salmonella pathogenicity island 1 (SPI-1). BarA, a sensor kinase postulated to interact with the response regulator SirA, is required for the expression of SPI-1 invasion genes. We found, however, that a barA null mutation had little effect on virulence using the mouse model for septicaemia. This confounding result led us to seek environmental signals present in the distal ileum that might supplant the need for BarA. We found that acetate restored the expression of invasion genes in the barA mutant, but had no effect on a sirA mutant. Acetate had its effect only at a pH that allowed its accumulation within the bacterial cytoplasm and not with the deletion of ackA and pta, the two genes required to produce acetyl-phosphate. These results suggest that the rising concentration of acetate in the distal ileum provides a signal for invasion gene expression by the production of acetyl-phosphate in the bacterial cytoplasm, a pathway that bypasses barA. We also found that a Delta(ackA-pta) mutation alone had no effect on virulence but, in combination with Delta(barA), it increased the oral LD50 24-fold. Thus, the combined loss of the BarA- and acetate-dependent pathways is required to reduce virulence. Two other short-chain fatty acids (SCFA), propionate and butyrate, present in high concentrations in the caecum and colon, had effects opposite to those of acetate: neither restored invasion gene expression in the barA mutant, and both, in fact, reduced expression in the wild-type strain. Further, a combination of SCFAs found in the distal ileum restored invasion gene expression in the barA mutant, whereas colonic conditions failed to do so and also reduced expression in the wild-type strain. These results suggest that the concentration and composition of SCFAs in the distal ileum provide a signal for productive infection by Salmonella, whereas those of the large intestine inhibit invasion.}, number={5}, journal={MOLECULAR MICROBIOLOGY}, author={Lawhon, SD and Maurer, R and Suyemoto, M and Altier, C}, year={2002}, month={Dec}, pages={1451–1464} }
 @article{gebreyes_altier_2002, title={Molecular characterization of multidrug-resistant Salmonella enterica subsp enterica serovar Typhimurium isolates from swine}, volume={40}, ISSN={["0095-1137"]}, DOI={10.1128/JCM.40.8.2813-2822.2002}, abstractNote={ABSTRACT As part of a longitudinal study of antimicrobial resistance among salmonellae isolated from swine, we studied 484 Salmonella enterica subsp. enterica serovar Typhimurium (including serovar Typhimurium var. Copenhagen) isolates. We found two common pentaresistant phenotypes. The first was resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (the AmCmStSuTe phenotype; 36.2% of all isolates), mainly of the definitive type 104 (DT104) phage type (180 of 187 isolates). The second was resistance to ampicillin, kanamycin, streptomycin, sulfamethoxazole, and tetracycline (the AmKmStSuTe phenotype; 44.6% of all isolates), most commonly of the DT193 phage type (77 of 165 isolates), which represents an unusual resistance pattern for DT193 isolates. We analyzed 64 representative isolates by amplified fragment length polymorphism (AFLP) analysis, which revealed DNA fingerprint similarities that correlated with both resistance patterns and phage types. To investigate the genetic basis for resistance among DT193 isolates, we characterized three AmKmStSuTe pentaresistant strains and one hexaresistant strain, which also expressed resistance to gentamicin (Gm phenotype), all of which had similar DNA fingerprints and all of which were collected during the same sampling. We found that the genes encoding the pentaresistance pattern were different from those from isolates of the DT104 phage type. We also found that all strains encoded all of their resistance genes on plasmids, unlike the chromosomally encoded genes of DT104 isolates, which could be transferred to Escherichia coli via conjugation, but that the plasmid compositions varied among the isolates. Two strains (strains UT08 and UT12) had a single, identical plasmid carrying bla TEM (which encodes ampicillin resistance), aphA1-Iab (which encodes kanamycin resistance), strA and strB (which encode streptomycin resistance), class B tetA (which encodes tetracycline resistance), and an unidentified sulfamethoxazole resistance allele. The third pentaresistant strain (strain UT20) was capable of transferring by conjugation two distinct resistance patterns, AmKmStSuTe and KmStSuTe, but the genes were carried on plasmids with slightly different restriction patterns (differing by a single band of 15 kb). The hexaresistant strain (strain UT30) had the same plasmid as strains UT08 and UT12, but it also carried a second plasmid that conferred the AmKmStSuGm phenotype. The second plasmid harbored the gentamicin resistance methylase ( grm ), which has not previously been reported in food-borne pathogenic bacteria. It also carried the sul1 gene for sulfamethoxazole resistance and a 1-kb class I integron bearing aadA for streptomycin resistance. We also characterized isolates of the DT104 phage type. We found a number of isolates that expressed resistance only to streptomycin and sulfamethoxazole (the StSu phenotype; 8.3% of serovar Typhimurium var. Copenhagen strains) but that had AFLP DNA fingerprints similar or identical to those of strains with genes encoding the typical AmCmStSuTe pentaresistance phenotype of DT104. These atypical StSu DT104 isolates were predominantly cultured from environmental samples and were found to carry only one class I integron of 1.0 kb, in contrast to the typical two integrons (InC and InD) of 1.0 and 1.2 kb, respectively, of the pentaresistant DT104 isolates. Our findings show the widespread existence of multidrug-resistant Salmonella strains and the diversity of multidrug resistance among epidemiologically related strains. The presence of resistance genes on conjugative plasmids and duplicate genes on multiple plasmids could have implications for the spread of resistance factors and for the stability of multidrug resistance among Salmonella serovar Typhimurium isolates.}, number={8}, journal={JOURNAL OF CLINICAL MICROBIOLOGY}, author={Gebreyes, WA and Altier, C}, year={2002}, month={Aug}, pages={2813–2822} }
 @article{allen_fedorka-cray_vazquez-torres_suyemoto_altier_ryder_fang_libby_2001, title={In Vitro and In Vivo Assessment of Salmonella enterica Serovar Typhimurium DT104 Virulence}, volume={69}, ISSN={0019-9567}, url={http://dx.doi.org/10.1128/iai.69.7.4673-4677.2001}, DOI={10.1128/IAI.69.7.4673-4677.2001}, abstractNote={Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has become a widespread cause of human and other animal infection worldwide. The severity of clinical illness in S. enterica serovar Typhimurium DT104 outbreaks has led to the suggestion that this strain possesses enhanced virulence. In the present study, in vitro and in vivo virulence-associated phenotypes of several clinical isolates of S. enterica serovar Typhimurium DT104 were examined and compared to S. enterica serovar Typhimurium ATCC 14028s. The ability of these DT104 isolates to survive within murine peritoneal macrophages, invade cultured epithelial cells, resist antimicrobial actions of reactive oxygen and nitrogen compounds, and cause lethal infection in mice were assessed. Our results failed to demonstrate that S. enterica serovar Typhimurium DT104 isolates are more virulent than S. enterica serovar Typhimurium ATCC 14028s.}, number={7}, journal={Infection and Immunity}, publisher={American Society for Microbiology}, author={Allen, C. A. and Fedorka-Cray, P. J. and Vazquez-Torres, A. and Suyemoto, M. and Altier, C. and Ryder, L. R. and Fang, F. C. and Libby, S. J.}, year={2001}, month={Jul}, pages={4673–4677} }
 @article{feng_laster_tompkins_brown_xu_altier_gomez_benfield_mccaw_2001, title={In utero infection by porcine reproductive and respiratory syndrome virus is sufficient to increase susceptibility of piglets to challenge by Streptococcus suis type II}, volume={75}, ISSN={["1098-5514"]}, DOI={10.1128/JVI.75.10.4889-4895.2001}, abstractNote={Porcine reproductive and respiratory syndrome (PRRS) consistently elevates the frequency of disease and mortality in young pigs. Many different secondary bacterial diseases occur in PRRS virus (PRRSV)-infected pigs. However, to date, establishing a reproducible experimental model of PRRSV infection in weaned pigs, with subsequent clinical disease following secondary bacterial challenge, has been difficult. PRRSV is frequently isolated during outbreaks from weak-born piglets affected by secondary bacterial diseases. This study was performed to investigate the potential role of intrauterine PRRSV infection on piglet susceptibility to secondary bacterial infection. PRRSV-free pregnant sows were intranasally infected at 98 days of gestation with PRRSV strain SD 23983. All piglets born to the PRRSV-infected sows were viremic. Piglets were removed from the sows at birth and deprived of colostrum. Piglets from PRRSV-infected and noninfected sows were randomly assigned to Streptococcus suis challenge or control subgroups. At 5 days of age, piglets were challenged intranasally with strain MN 87555 of S. suis type II. Total and differential leukocyte counts were performed on blood samples collected at 3 days of age. The numbers of leukocytes, lymphocytes, and monocytes were significantly reduced in the PRRSV-infected piglets. Lesions were observed in bone marrow, brain, lung, heart, spleen, lymph node, tonsil, and thymus of PRRSV-infected piglets. Thymus/body weight ratios of in utero PRRSV-infected piglets were significantly reduced compared to those of non-PRRSV-infected piglets, and thymic lesions were characterized by severe cortical depletion of thymocytes. Lesions were not observed in piglets born to PRRSV-free sows. Overall, 20 out of 22 piglets in the PRRSV-S. suis dual-infection group died within 1 week after challenge with S. suis (10 of 11 in each of two trials). This contrasts with 1 of 18 piglets in the PRRSV-infection-only group and 5 of 23 piglets in the S. suis-challenge-only group (1 of 12 in trial 1 and 4 of 11 in trial 2). No piglets died in the uninfected control groups. Most of the piglets in the PRRSV-S. suis dual-infection group developed suppurative meningitis. S. suis type II was recovered from their brains and joints. These results indicate that in utero infection by PRRSV makes piglets more susceptible to infection and disease following challenge by S. suis type II. In utero infection by PRRSV may provide a useful model to study the interaction between PRRSV and bacterial coinfections in piglets.}, number={10}, journal={JOURNAL OF VIROLOGY}, author={Feng, WH and Laster, SM and Tompkins, M and Brown, T and Xu, JS and Altier, C and Gomez, W and Benfield, D and McCaw, MB}, year={2001}, month={May}, pages={4889–4895} }
 @misc{altier_2001, title={NCCLS quality control values for veterinary- use fluoroquinolones - Author's reply}, volume={39}, number={4}, journal={Journal of Clinical Microbiology}, author={Altier, C.}, year={2001}, pages={1681} }
 @article{gebreyes_davies_morrow_funk_altier_2000, title={Antimicrobial resistance of Salmonella isolates from swine}, volume={38}, number={12}, journal={Journal of Clinical Microbiology}, author={Gebreyes, W. A. and Davies, P. R. and Morrow, W. E. M. and Funk, J. A. and Altier, C.}, year={2000}, pages={4633–4636} }
 @article{altier_suyemoto_ruiz_burnham_maurer_2000, title={Characterization of two novel regulatory genes affecting Salmonella invasion gene expression}, volume={35}, ISSN={["1365-2958"]}, DOI={10.1046/j.1365-2958.2000.01734.x}, abstractNote={A Salmonella typhimurium chromosomal deletion removing ≈19 kb of DNA at centisome 65 reduces invasion of cultured epithelial cells as well as the expression of lacZY operon fusions to several genes required for the invasive phenotype. As the deleted region contains no genes previously known to affect Salmonella invasion, we investigated the roles of individual genes in the deleted region using a combination of cloning, complementation and directed mutation. We find that the deletion includes two unrelated regulatory genes. One is the Salmonella homologue of Escherichia coli barA (airS ), which encodes a member of the multistep phosphorelay subgroup of two-component sensor kinases. The action of BarA is coupled to that of SirA, a member of the phosphorylated response regulator family of proteins, and includes both HilA-dependent and HilA-independent components. The other regulatory gene removed by the deletion is the Salmonella homologue of E. coli csrB, which specifies a regulatory RNA implicated in controlling specific message turnover in E. coli. These results identify a protein that is likely to play a key role in the environmental control of Salmonella invasion gene expression, and they also suggest that transcriptional control of invasion genes could be subject to refinement at the level of message turnover.}, number={3}, journal={MOLECULAR MICROBIOLOGY}, author={Altier, C and Suyemoto, M and Ruiz, AI and Burnham, KD and Maurer, R}, year={2000}, month={Feb}, pages={635–646} }
 @article{riddle_lemons_papich_altier_2000, title={Evaluation of ciprofloxacin as a representative of veterinary fluoroquinolones in susceptibility testing}, volume={38}, number={4}, journal={Journal of Clinical Microbiology}, author={Riddle, C. and Lemons, C. L. and Papich, M. G. and Altier, C.}, year={2000}, pages={1636–1637} }
 @article{altier_suyemoto_lawhon_2000, title={Regulation of Salmonella enterica serovar typhimurium invasion genes by csrA}, volume={68}, ISSN={["1098-5522"]}, DOI={10.1128/IAI.68.12.6790-6797.2000}, abstractNote={ABSTRACT Penetration of intestinal epithelial cells by Salmonella enterica serovar Typhimurium requires the expression of invasion genes, found in Salmonella pathogenicity island 1 (SPI1), that encode components of a type III secretion apparatus. These genes are controlled in a complex manner by regulators within SPI1, including HilA and InvF, and those outside SPI1, such as the two-component regulators PhoP/PhoQ and BarA/SirA. We report here that epithelial cell invasion requires the serovar Typhimurium homologue of Escherichia coli csrA , which encodes a regulator that alters the stability of specific mRNA targets. A deletion mutant of csrA was unable to efficiently invade cultured epithelial cells and showed reduced expression of four tested SPI1 genes, hilA, invF, sipC , and prgH . Overexpression of csrA from an induced araBAD promoter also negatively affected the expression of these genes, indicating that CsrA can act as both a positive and a negative regulator of SPI1 genes and suggesting that the bacterium must tightly control the level or activity of CsrA to achieve maximal invasion. We found that CsrA affected hilA , a regulator of the other three genes we tested, probably by controlling one or more genetic elements that regulate hilA . We also found that both the loss and the overexpression of csrA reduced the expression of two regulators of hilA, hilC and hilD , suggesting that csrA exerts its control of hilA through one or both of these regulators. We further found, however, that CsrA could affect the expression of both invF and sipC independent of its effects on hilA . One additional striking phenotype of the csrA mutant, not observed in a comparable E. coli mutant, was its slow growth. Phenotypic revertants that had normal growth rates, while maintaining the csrA mutation, were common. These suppressed strains, however, did not recover the ability to invade cultured cells, indicating that the csrA -mediated loss of invasion cannot be attributed simply to poor growth and that the growth and invasion deficits of the csrA mutant arise from effects of CsrA on different targets.}, number={12}, journal={INFECTION AND IMMUNITY}, author={Altier, C and Suyemoto, M and Lawhon, SD}, year={2000}, month={Dec}, pages={6790–6797} }
 @article{altier_suyemoto_1999, title={A recombinase-based selection of differentially expressed bacterial genes}, volume={240}, ISSN={["1879-0038"]}, DOI={10.1016/S0378-1119(99)00427-8}, abstractNote={Bacterial genes are often differentially expressed in response to specific environmental conditions. We have devised a method to identify regulated bacterial promoters, such that transient promoter expression leads to a permanent and selectable change in bacterial phenotype. This system consists of a promoterless derivative of cre, the phage P1 recombinase, carried on a plasmid, and two chromosomal loxP sites, the targets of the Cre recombinase. The loxP sites flank npt, conferring kanamycin resistance, and sacB, which confers sensitivity to sucrose, allowing positive selection for both the presence and absence of this chromosomal cassette. Fusion of active promoters to cre induces recombination of the loxP sites and deletion of intervening DNA, allowing selection on media containing sucrose, while inactive promoters fail to induce recombination and so remain resistant to kanamycin. We tested the system in Salmonella typhimurium using a known regulated promoter, that from the araBAD operon, and found it to be a sensitive indicator of gene expression over a wide range of promoter induction. We then used this system to identify S. typhimurium genes that are specifically expressed when bacteria interact with cultured epithelial cells and identified a novel DNA fragment, not found in E. coli, which might represent part of a new pathogenicity island.}, number={1}, journal={GENE}, author={Altier, C and Suyemoto, M}, year={1999}, month={Nov}, pages={99–106} }
 @article{lewbart_stoskopf_losordo_geyer_owen_smith_law_altier_1999, title={Safety and efficacy of the Environmental Products Group Masterflow Aquarium Management System with Aegis Microbe Shield (TM)}, volume={19}, ISSN={["0144-8609"]}, DOI={10.1016/S0144-8609(98)00043-0}, abstractNote={Abstract This study investigated the safety and efficacy of the EPG Masterflow Aquarium Management System with Aegis Microbe Shield™ (EPG-MAMS). Four different species of fish were used in the study. Ten fish of each species were placed in 75 l aquariums containing the EPG filter media, a commercially available filter media (Whisper®) and an aquarium with no filter material. At the end of the 45 day trial three fish from each tank were sacrificed and preserved in formalin for histopathology. Water quality parameters were routinely monitored. The EPG filter media was compared with the Whisper® filter media for efficacy against Aeromonas salmonicida using a shaker flask microbiological assay. The EPG filter proved to be clinically and histopathologically safe and reduced to some degree the number of A. salmonicida suspended in water in an in vitro study.}, number={2}, journal={AQUACULTURAL ENGINEERING}, author={Lewbart, GA and Stoskopf, MK and Losordo, T and Geyer, J and Owen, J and Smith, DW and Law, M and Altier, C}, year={1999}, month={Jan}, pages={93–98} }
 @article{sellon_walker_suyemoto_altier_1997, title={Nucleic acid amplification for rapid detection of Rhodococcus equi in equine blood and tracheal wash fluids}, volume={58}, number={11}, journal={American Journal of Veterinary Research}, author={Sellon, D. C. and Walker, K. and Suyemoto, M. M. and Altier, C.}, year={1997}, pages={1232–1237} }