Barbara A Byrne

University of California, Davis, Davis, California, United States

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Publications (59)129.35 Total impact

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    ABSTRACT: The development of antimicrobial resistance among bacteria (AMR) is currently one of the world’s most pressing public health problems. The use of antimicrobial agents in humans and animals has resulted in AMR which has narrowed the potential use of antibiotics for the treatment of infections in humans. To monitor AMR and to develop control measures, some countries, such as the USA, Canada and Denmark, have established national integrated surveillance systems (FDA, 2012, CIPARS, 2007, DANMAP, 2012). The components of these programs monitor changes in susceptibility/resistance to antimicrobial agents of selected zoonotic pathogens and commensal organisms recovered from animals, retail meats and humans. The rapid development of Colombia’s animal production industry has raised food safety issues including the emergence of antibiotic resistance. The Colombian Integrated Surveillance Program for Antimicrobial Resistance (COIPARS) was established as a pilot project to monitor AMR on poultry farms, slaughter houses and retail markets.
    Zoonoses and Public Health 04/2015; 62(Suppl. 1):58–69. DOI:10.1111/zph.12192 · 2.07 Impact Factor
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    ABSTRACT: Salmonella Paratyphi B dT+ variant (also termed Salmonella Java) and Salmonella Heidelberg are pathogens of public health importance that are frequently isolated from poultry. As a step toward implementing the Colombian Integrated Program for Antimicrobial Resistant Surveillance, this study characterized molecular patterns of Salmonella Paratyphi B dT+ and Salmonella Heidelberg isolated from poultry farms, fecal samples, and retail chicken meat using pulsed-field gel electrophoresis (PFGE). The objective of this study was to determine the genetic relationship among isolates and to determine potential geographically predominant genotypes. Based on PFGE analysis, both serovars exhibited high heterogeneity: the chromosomal DNA fingerprints of 82 Salmonella Paratyphi B dT+ isolates revealed 42 PFGE patterns, whereas the 21 isolates of Salmonella Heidelberg revealed 10 patterns. Similar genotypes of both serovars were demonstrated to be present on farms and in retail outlets. For Salmonella Paratyphi B dT+, closely genetically related strains were found among isolates coming from different farms and different integrated poultry companies within two departments (Santander and Cundinamarca) and also from farms located in the two geographically distant departments. For Salmonella Heidelberg, there were fewer farms with genetically related isolates than for Salmonella Paratyphi B dT+. A possible dissemination of similar genotypes of both serovars along the poultry production chain is hypothesized, and some facilitating factors existing in Colombia are reviewed.
    Journal of food protection 04/2015; 78(4):802-7. DOI:10.4315/0362-028X.JFP-14-356 · 1.80 Impact Factor
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    ABSTRACT: As a step toward implementing the Colombian Integrated Program for Antimicrobial Resistance Surveillance (COIPARS), this study aimed to establish the baseline antimicrobial resistance patterns of Salmonella serovars, Escherichia coli, and Enterococcus spp. isolates in retail poultry meat from independent stores and from a main chain distributor center. MICs of the isolates were determined for antimicrobials used both in humans and animals, using an automated system. Salmonella serovars were isolated from 26% of the meat samples and E. coli from 83%, whereas Enterococcus faecalis and Enterococcus faecium were detected in 81 and 13% of the meat samples, respectively. A principal finding of concern in this study was that almost 98% of isolates tested were multidrug resistant. Ceftiofur, enrofloxacin, nalidixic acid, and tetracycline were the antimicrobials that showed the highest frequency of resistance among Salmonella and E. coli isolates. For enterococci, 61.5% of E. faecium isolates were found to be resistant to quinupristin-dalfopristin; this is significant because it is used to treat nosocomial infections when vancomycin resistance is present. Vancomycin resistance was detected in 4% of the E. faecalis isolates. The results of our study highlight the need for rapid implementation of an integrated program for surveillance of antimicrobial resistance by the Colombian authorities in order to monitor trends, raise awareness, and help promote practices to safeguard later generation antimicrobial agents.
    Journal of food protection 04/2015; 78(4):751-9. DOI:10.4315/0362-028X.JFP-14-349 · 1.80 Impact Factor
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    ABSTRACT: The Gram positive bacterial coccus Streptococcus infantarius subspecies coli is increasingly linked with development of fatal vegetative infective endocarditis and septicemia in humans, sea otters (Enhydra lutris) and other animals. However, the pathogenesis of these infections is poorly understood. Using S. infantarius subsp. coli strains isolated from sea otters with infective endocarditis, this study evaluated adherence and invasion of epithelial and endothelial cells, adherence to extracellular matrix components, and macrophage survival. Significant adherence to endothelial-derived cells was observed for 62% of isolates, 24% adhered to epithelial cell lines, and 95% invaded one or both cell types in vitro. The importance of the hyaluronic acid capsule in host cell adherence and invasion was also evaluated. Capsule removal significantly reduced epithelial adherence and invasion for most S. infantarius subsp. coli isolates, suggesting that the capsule facilitates attachment to and invasion of epithelium. Enzyme-linked immunosorbent assay testing revealed that all isolates adhered significantly to the extracellular matrix components collagen IV, fibronectin, laminin and hyaluronic acid. Finally, significant bacterial survival following phagocytosis by macrophages was apparent for 81% of isolates at one or more time points. Taken collectively these findings indicate that S. infantarius subsp. coli has multiple pathogenic properties that may be important to host colonization, invasion and disease. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Comparative immunology, microbiology and infectious diseases 03/2015; 40. DOI:10.1016/j.cimid.2015.03.002 · 2.11 Impact Factor
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    ABSTRACT: The bacterium Salmonella enterica can infect marine mammals and has been increasingly implicated in seafood-borne disease outbreaks in humans. Despite the risk this zoonotic agent poses to animals and people, little is known regarding the environmental factors that affect its persistence in the sea. The goal of this study was to evaluate the impact of two constituents on the survival of Salmonella in the marine environment: transparent exopolymer particles (TEP) and suspended particles. A decay experiment was conducted by spiking Salmonella into bottles containing seawater, seawater with alginic acid as a source of TEP, filtered seawater or filtered seawater with alginic acid. Survival of Salmonella was monitored using culture followed by enrichment assays to evaluate if the bacteria entered a viable but non-cultivable (VBNC) state. Salmonella cell counts dropped significantly faster (P ≤ 0.05) in the unfiltered seawater samples with and without TEP. The slowest decay occurred in filtered seawater containing alginic acid, with VBNC Salmonella persisting for 17 months. These findings suggest that TEP may favor Salmonella survival while suspended particles facilitate its decay. Insight on the survival of allochthonous, zoonotic pathogens in seawater can guide monitoring, management and policy decisions relevant to wildlife and human public health. © FEMS 2015. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
    FEMS Microbiology Ecology 03/2015; 91(3). DOI:10.1093/femsec/fiv005 · 3.88 Impact Factor
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    ABSTRACT: Few studies report the minimum inhibitory concentrations for antimicrobials against equine Corynebacterium pseudotuberculosis isolates. To evaluate trends in the in vitro activities of 20 antimicrobials against equine Corynebacterium pseudotuberculosis isolates from 1996 to 2012 and to determine if a relationship exists between the minimum inhibitory concentration (MIC) and location of the abscess. Corynebacterium pseudotuberculosis isolates from 196 horses with naturally occurring disease. Retrospective and cross-sectional design. Medical records were reviewed to obtain clinical and MIC data. Minimum inhibitory concentrations were determined by the microdilution technique. The MIC results over 3 periods were compared (1996-2001, 2002-2006, 2007-2012). The MIC90 values for clinically relevant antimicrobials were as follows: chloramphenicol ≤4 μg/mL, enrofloxacin ≤0.25 μg/mL, gentamicin ≤1 μg/mL, penicillin =0.25 μg/mL, rifampin ≤1 μg/mL, tetracycline ≤2 μg/mL, trimethoprim-sulfamethoxazole (TMS) ≤0.5 μg/mL, ceftiofur =2 μg/mL, and doxycycline ≤2 μg/mL. There were no significant changes in MIC results over the study period. There was no relationship between MIC patterns and abscess location. The MIC50 and MIC90 values of antimicrobials evaluated in this study for equine isolates of C. pseudotuberculosis did not vary over time. Abscess location was not associated with different MIC patterns in cultured isolates. Several commonly used antimicrobials are active in vitro against C. pseudotuberculosis in vitro. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of American College of Veterinary Internal Medicine.
    Journal of Veterinary Internal Medicine 01/2015; 29(1). DOI:10.1111/jvim.12534 · 2.22 Impact Factor
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    ABSTRACT: Abstract Since 2002, an increased number of northern sea otters (Enhydra lutris kenyoni) from southcentral Alaska have been reported to be dying due to endocarditis and/or septicemia with infection by Streptococcus infantarius subsp. coli. Bartonella spp. DNA was also detected in northern sea otters as part of mortality investigations during this unusual mortality event (UME) in Kachemak Bay, Alaska. To evaluate the extent of exposure to Bartonella spp. in sea otters, sera collected from necropsied and live-captured northern sea otters, as well as necropsied southern sea otters (Enhydra lutris nereis) unaffected by the UME, were analyzed using an immunofluorescent antibody assay. Antibodies against Bartonella spp. were detected in sera from 50% of necropsied and 34% of presumed healthy, live-captured northern sea otters and in 16% of necropsied southern sea otters. The majority of sea otters with reactive sera were seropositive for B. washoensis, with antibody titers ranging from 1:64 to 1:256. Bartonella spp. antibodies were especially common in adult northern sea otters, both free-living (49%) and necropsied (62%). Adult stranded northern sea otters that died from infectious causes, such as opportunistic bacterial infections, were 27 times more likely to be Bartonella seropositive than adult stranded northern sea otters that died from noninfectious causes (p<0.001; 95% confidence interval 2.62-269.4). Because Bartonella spp. antibodies were detected in necropsied northern sea otters from southcentral (44%) and southwestern (86%) stocks of Alaska, as well as in necropsied southern sea otters (16%) in southcentral California, we concluded that Bartonella spp. exposure is widely distributed among sea otter populations in the Eastern Pacific, providing context for investigating future disease outbreaks and monitoring of Bartonella infections for sea otter management and conservation.
    Vector Borne and Zoonotic Diseases 12/2014; 14(12):831-7. DOI:10.1089/vbz.2014.1612 · 2.53 Impact Factor
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    ABSTRACT: Salmonella is a genus of zoonotic bacteria that can infect a variety of animals, and may cause gastrointestinal disease in marine mammals. Many of the same Salmonella serotypes are shed by California sea lions (Zalophus californianus) and humans, which poses transmission questions and public health concerns. In this study, 454 fecal samples from three free-ranging California sea lion populations along the California coast and from animals undergoing rehabilitation at The Marine Mammal Center, Sausalito, California, were screened for the presence of Salmonella. In addition to fecal samples, 39 presumed vomitus samples were collected and processed. Of the 454 samples processed, 312 were from free-ranging sites and 142 were from rehabilitating California sea lions. A total of nine fecal samples were positive for Salmonella, yielding a 2.0% overall prevalence, as well as two presumed vomitus samples (5.1% prevalence). Salmonella shedding prevalence was 1.6% in samples collected from free-ranging animals, and 2.8% in rehabilitating animals. Four serotypes were found among the 11 positive samples, with Salmonella Enteritidis the most prevalent (64%). Antimicrobial resistance testing and pulsed-field gel electrophoresis were performed to further characterize isolates. Experiments were carried out to determine the minimal number of Salmonella required for detection by the methods used. It was determined that at least 10' colony-forming units per gram of feces was required for detection. The prevalence of Salmonella Enteritidis, and diversity of serotypes discovered is considerably different from those reported in previous studies. Overall, this study provides new insights into the epidemiology of Salmonella in California sea lions present in multi-use coastal ecosystems.
    Journal of Zoo and Wildlife Medicine 09/2014; 45(3):527-33. DOI:10.1638/2013-0197R1.1 · 0.32 Impact Factor
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    ABSTRACT: Since 2002, vegetative valvular endocarditis (VVE), septicemia and meningoencephalitis have contributed to an Unusual Mortality Event (UME) of northern sea otters in southcentral Alaska. Streptococcal organisms were commonly isolated from vegetative lesions and organs from these sea otters. Bartonella infection has also been associated with bacteremia and VVE in terrestrial mammals, but little is known regarding its pathogenic significance in marine mammals. Our study evaluated whether Streptococcus bovis/equinus (SB/E) and Bartonella infections were associated with UME-related disease characterized by VVE and septicemia in Alaskan sea otter carcasses recovered 2004-2008. These bacteria were also evaluated in southern sea otters in California. Streptococcus bovis/equinus were cultured from 45% (23/51) of northern sea otter heart valves, and biochemical testing and sequencing identified these isolates as Streptococcus infantarius subsp. coli. One-third of sea otter hearts were co-infected with Bartonella spp. Our analysis demonstrated that SB/E was strongly associated with UME-related disease in northern sea otters (P < 0.001). While Bartonella infection was also detected in 45% (23/51) and 10% (3/30) of heart valves of northern and southern sea otters examined, respectively, it was not associated with disease. Phylogenetic analysis of the Bartonella ITS region allowed detection of two Bartonella species, one novel species closely related to Bartonella spp. JM-1, B. washoensis and Candidatus B. volans and another molecularly identical to B. henselae. Our findings help to elucidate the role of pathogens in northern sea otter mortalities during this UME and suggested that Bartonella spp. is common in sea otters from Alaska and California.
    Veterinary Microbiology 06/2014; 170(3-4). DOI:10.1016/j.vetmic.2014.02.021 · 2.73 Impact Factor
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    ABSTRACT: Objective-To evaluate the performance of a veterinary urine dipstick paddle (UDP) for diagnosis and identification of urinary tract infection (UTI) in dogs and cats. Design-Prospective, randomized, blinded study. Sample-207 urine specimens. Procedures-UDPs were inoculated by 2 investigators and incubated according to manufacturer's instructions. Results, including presence or absence of bacterial growth, organism counts, and identification of uropathogens, were compared between investigators and with microbiology laboratory results. A subset of UDPs with bacterial growth was submitted to the laboratory for confirmation. Results-The laboratory reported 64 (30.9%) specimens had growth of bacteria. Bacterial growth was reported for 63 (30.4%) and 58 (28.0%) of the UDPs by investigators 1 and 2, respectively. Sensitivity and specificity of the UDP for detection of bacterial growth were 97.3% and 98.6%, respectively, for investigator 1 and 89.1% and 99.3%, respectively, for investigator 2. For UPDs with ≥ 10(5) colony-forming units/mL, organism counts correlated well between the laboratory and investigators 1 (r = 0.95) and 2 (r = 0.89). Pathogen identification was not always accurate. Only 25 of 33 (75.8%) UDPs submitted for confirmation yielded bacteria consistent with those isolated from the original bacterial culture of urine. Conclusions and Clinical Relevance-The veterinary UDP system was a sensitive test for screening patients for bacterial UTI, but uropathogen identification was not always accurate. When UDPs have bacterial growth, a fresh urine specimen should be submitted to the laboratory to confirm the identity of the organisms and to permit antimicrobial susceptibility testing.
    Journal of the American Veterinary Medical Association 04/2014; 244(7):814-9. DOI:10.2460/javma.244.7.814 · 1.67 Impact Factor
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    ABSTRACT: Objective-To determine the pharmacokinetics of ceftiofur crystalline-free acid (CCFA) following SC administration of a single dose to sheep. Animals-9 healthy adult female Suffolk-crossbred sheep. Procedures-Each sheep was administered 6.6 mg of CCFA/kg, SC, in the cervical region once. Serial blood samples were collected at predetermined intervals for 14 days. Serum concentration of ceftiofur free-acid equivalents (CFAE) was determined by high-performance liquid chromatography. Pharmacokinetic parameters were determined by compartmental and noncompartmental methods. Results-Pharmacokinetics for CCFA following SC administration in sheep was best described with a 1-compartment model. Mean ± SD area under the concentration-time curve from time 0 to infinity, peak serum concentration, and time to peak serum concentration were 206.6 ± 24.8 μ•h/mL, 2.4 ± 0.5 μg/mL, and 23.1 ± 10.1 h, respectively. Serum CFAE concentrations ≥ 1 μg/mL (the target serum CFAE concentration for treatment of disease caused by Mannheimia haemolytica and Pasteurella multocida) were maintained for 2.6 to 4.9 days. No significant adverse reactions to CCFA administration were observed. Conclusions and Clinical Relevance-Results indicated that adequate therapeutic serum concentrations of CFAE for treatment of disease caused by M haemolytica and P multocida were achieved in sheep following SC administration of a single dose (6.6 mg/kg) of CCFA. Thus, CCFA might be useful for the treatment of common respiratory tract pathogens in sheep.
    American Journal of Veterinary Research 03/2014; 75(3):290-5. DOI:10.2460/ajvr.75.3.290 · 1.21 Impact Factor
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    ABSTRACT: Aspergillosis remains a major cause of mortality in captive and rehabilitated seabirds. To date, there has been poor documentation of fungal (particularly Aspergillus spp.) burdens in natural seabird loafing and roosting sites compared with fungal numbers in rehabilitation or captive settings and the various microenvironments that seabirds are exposed to during the rehabilitation process. This study compares fungal, particularly Aspergillus spp., burdens potentially encountered by seabirds in natural and rehabilitation environments. Differences among the various microenvironments in the rehabilitation facility were evaluated to determine the risk of infection when seabirds are experiencing high stress and poor immune function. Aspergillus spp. counts were quantified in three wildlife rehabilitation centers and five natural seabird loafing and roosting sites in northern California using a handheld impact air sampler and a water filtration system. Wildlife rehabilitation centers demonstrated an increase in numbers of conidia of Aspergillus spp. and Aspergillus fumigatus in air and water samples from select aquatic bird rehabilitation centers compared with natural seabird environments in northern California. Various microenvironments in the rehabilitation facility were identified as having higher numbers of conidia of Aspergillus spp. These results suggest that periodic monitoring of multiple local areas, where the birds spend time in a rehabilitation facility, should be done to identify "high risk" sites, where birds should spend minimal time, or sites that should be cleaned more frequently or have improved air flow to reduce exposure to fungal conidia. Overall, these results suggest that seabirds may be more likely to encounter Aspergillus spp. in various microenvironments in captivity, compared with their native habitats, which could increase their risk of developing disease when in a debilitated state.
    Journal of Zoo and Wildlife Medicine 03/2014; 45(1):29-40. DOI:10.1638/2012-0051R1.1 · 0.32 Impact Factor
  • 02/2014; 174(10). DOI:10.1136/vr.101975
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    ABSTRACT: Burkholderia pseudomallei, the causative agent of melioidosis, was isolated from abscesses of 2 pet green iguanas in California, USA. The international trade in iguanas may contribute to importation of this pathogen into countries where it is not endemic and put persons exposed to these animals at risk for infection.
    Emerging Infectious Diseases 02/2014; 20(2):304-6. DOI:10.3201/eid2002.131314 · 7.33 Impact Factor
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    ABSTRACT: Recent studies have suggested a potential role for wild birds in zoonotic transmission of Campylobacter jejuni, the leading cause of gastroenteritis in humans worldwide. In this study, we detected Campylobacter spp. in 66.9% (85/127) of free-ranging American crows (Corvus brachyrhyncos) sampled in the Sacramento Valley of California in 2012 and 2013. Biochemical testing and sequence analysis of 16S rRNA revealed that 93% of isolates (n=70) were C. jejuni, with cytolethal distending toxin (CDT) and flagellin A genes detected by PCR in 20% and 46% of the C. jejuni isolates (n=59), respectively. The high prevalence of C. jejuni, coupled with the occurrence of known virulence markers CDT and flagellin A, demonstrates that crows shed Campylobacter spp. in their feces that are potentially pathogenic to humans. Crows are abundant in urban, suburban, and agricultural settings, and thus further study to determine their role in zoonotic transmission of Campylobacter will inform public health.
    Applied and Environmental Microbiology 12/2013; DOI:10.1128/AEM.03393-13 · 3.95 Impact Factor
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    ABSTRACT: Stress-induced hormones can alter the inflammatory response to tissue injury, however, the precise mechanism by which epinephrine influences inflammatory response and wound healing is not well defined. Here we demonstrate that epinephrine alters the neutrophil (PMN)-dependent inflammatory response to a cutaneous wound. Using non-invasive real-time imaging of genetically-tagged PMNs in a murine skin wound, chronic, epinephrine-mediated stress was modeled by sustained delivery of epinephrine. Prolonged systemic exposure of epinephrine resulted in persistent PMN trafficking to the wound site via an IL-6 mediated mechanism, and this in turn impaired wound repair. Further, we demonstrate that β2 adrenergic receptor-dependent activation of pro-inflammatory macrophages is critical for epinephrine-mediated IL-6 production. This study expands our current understanding of stress hormone-mediated impairment of wound healing and provides an important mechanistic link to explain how epinephrine stress exacerbates inflammation via increased number and lifetime of PMNs.Journal of Investigative Dermatology accepted article preview online, 11 October 2013. doi:10.1038/jid.2013.415.
    Journal of Investigative Dermatology 10/2013; 134(3). DOI:10.1038/jid.2013.415 · 6.37 Impact Factor
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    ABSTRACT: The presence of subtilase-cytotoxin-encoding genes was determined in 397 environmental Escherichia coli strains isolated from water, suspended solids, and sediments sampled from different hydrological and environmental conditions in a California estuary. A total of 7 strains (1.76%) were found to harbor subtilase-cytotoxin-encoding genes. Using primers targeting subA only, we generated PCR amplicons from 2 strains; while using primers targeting the 3' end of SubA downstream to the 5' end of SubB, amplicons of 232 bp were generated from 5 additional strains. The 556 bp subA sequences were almost identical to that in the subtilase-cytotoxin-positive strain ED 591 (98%), while subAB sequences of 2 non-Shiga-toxigenic strains revealed 100% similarity with the Shiga-toxigenic E. coli O113:H21 strain 98NK2 that was isolated from an outbreak of hemolytic uremic syndrome. Additionally, the serogroup O113:H21 was present in this collection of environmental E. coli, and it was found to harbor stx2d, hra1 that encodes the heat resistant agglutinin 1, and a subAB sequence similar to that in the non-Shiga-toxigenic E. coli subtilase cytotoxin strain ED 591. To further understand potential health risks posed by strains encoding SubAB, future epidemiological studies should consider screening isolates for subAB regardless of the presence of Shiga-toxin-encoding genes.
    Canadian Journal of Microbiology 06/2013; 59(6):437-41. DOI:10.1139/cjm-2012-0606 · 1.18 Impact Factor
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    ABSTRACT: Case Description-6 lactating dairy goats were examined because of acute mastitis. Clinical Findings-Goats were considered to have endotoxemia on the basis of physical examination and clinicopathologic findings. The affected udder halves had gangrenous discolored distal portions with sharp demarcations from grossly normal tissue proximally. Udder secretions from the affected sides were serosanguineous in all cases. A Bacillus sp was isolated in pure cultures in all cases. In 1 case, the Bacillus sp was identified as Bacillus cereus. Treatment and Outcome-Goats were treated for mastitis and endotoxemia with polyionic IV fluid therapy, systemic and intramammary antimicrobial administration, anti-inflammatory drug administration, and other supportive treatment. All goats survived to discharge. All except 1 goat had follow-up information available. The affected udder halves sloughed in 1 to 2 months following discharge. In subsequent lactations after the mastitis episodes, milk production in 2 of 5 goats was above the mean, as determined on the basis of Dairy Herd Improvement records, and 3 of 5 goats were voluntarily withdrawn from lactation. All 5 goats had successful kiddings after the Bacillus mastitis episode. Conclusions and Clinical Relevance-Bacillus sp should be considered as a causative agent in goats with gangrenous mastitis, especially when the Bacillus sp is isolated in a pure culture. Antimicrobial sensitivity testing is recommended for selection of an appropriate antimicrobial for treatment. Prognosis for survival appears to be good, although milk production may be decreased.
    Journal of the American Veterinary Medical Association 03/2013; 242(6):836-43. DOI:10.2460/javma.242.6.836 · 1.67 Impact Factor
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    ABSTRACT: In July 2010, a horse from a rural farm (Farm A) in coastal Northern California was diagnosed with Salmonella Oranienburg infection following referral to a veterinary hospital for colic surgery. Environmental sampling to identify potential sources and persistence of Salmonella on the farm was conducted from August 2010 to March 2011. Salmonella was cultured using standard enrichment and selective plating. Pure colonies were confirmed by biochemical analysis, serotyped and compared by pulsed-field gel electrophoresis (PFGE) analysis. A total of 204 clinical and environmental samples at Farm A were analysed, and Salmonella spp. was isolated from six of eight (75%) horses, an asymptomatic pet dog, two of seven (28.6%) water samples from horse troughs, nine of 20 (45%) manure storage pile composites, 16 of 71 (22.5%) wild turkey faeces and four of 39 (10.3%) soil samples from the family's edible home garden. Well water and garden vegetable samples and horse faecal samples from a neighbouring ranch were negative. S. Oranienburg with a PFGE pattern indistinguishable from the horse clinical strain was found in all positive sample types on Farm A. The investigation illustrates the potential for widespread dissemination of Salmonella in a farm environment following equine infections. We speculate that a recent surge in the wild turkey population on the property could have introduced S. Oranienburg into the herd, although we cannot rule out the possibility wild turkeys were exposed on the farm or to other potential sources of Salmonella. Findings from the investigation indicated that raw horse manure applied as fertilizer was the most likely source of garden soil contamination. Viable S. Oranienburg persisted in garden soil for an estimated 210 days, which exceeds the 120-day standard between application and harvest currently required by the National Organic Program. The study underscores the need to educate the public about potential food safety hazards associated with using raw animal manure to fertilize edible home gardens.
    Zoonoses and Public Health 02/2013; 61(1). DOI:10.1111/zph.12043 · 2.07 Impact Factor
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    ABSTRACT: Given their coastal site fidelity and opportunistic foraging behavior, harbor seals (Phoca vitulina) may serve as sentinels for coastal ecosystem health. Seals using urbanized coastal habitat can acquire enteric bacteria, including Vibrio that may affect their health. To understand Vibrio dynamics in seals, demographic and environmental factors were tested for predicting potentially virulent Vibrio in free-ranging and stranded Pacific harbor seals (Phoca vitulina richardii) off California. Vibrio prevalence did not vary with season and was greater in free-ranging seals (29 %, n = 319) compared with stranded seals (17 %, n = 189). Of the factors tested, location, turbidity, and/or salinity best predicted Vibrio prevalence in free-ranging seals. The relationship of environmental factors with Vibrio prevalence differed by location and may be related to oceanographic or terrestrial contributions to water quality. Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio cholerae were observed in seals, with V. cholerae found almost exclusively in stranded pups and yearlings. Additionally, virulence genes (trh and tdh) were detected in V. parahaemolyticus isolates. Vibrio cholerae isolates lacked targeted virulence genes, but were hemolytic. Three out of four stranded pups with V. parahaemolyticus (trh+ and/or tdh+) died in rehabilitation, but the role of Vibrio in causing mortality is unclear, and Vibrio expression of virulence genes should be investigated. Considering that humans share the environment and food resources with seals, potentially virulent Vibrio observed in seals also may be of concern to human health.
    Microbial Ecology 02/2013; DOI:10.1007/s00248-013-0188-1 · 3.12 Impact Factor

Publication Stats

379 Citations
129.35 Total Impact Points

Institutions

  • 2006–2015
    • University of California, Davis
      • • Department of Pathology, Microbiology and Immunology (VM)
      • • School of Veterinary Medicine
      Davis, California, United States
  • 2012
    • California State University, Monterey Bay
      • Division of Science and Environmental Policy (SEP)
      Seaside, California, United States
  • 2010
    • California Department of Fish and Wildlife
      Sacramento, California, United States
  • 2007
    • Pacific Marine Mammal Center
      Laguna Beach, California, United States