case report isolation of corynebacterium...

Case ReportIsolation of Corynebacterium pseudotuberculosis Biovar equifrom a Horse in Central Iowa

Kate L Hepworth-Warren1 Beatrice T Sponseller1

David M Wong1 and Joann M Kinyon2

1 Department of Veterinary Clinical Sciences College of Veterinary Medicine Iowa State University1600 SE 16th Street Ames IA 50011 USA

2Department of Veterinary Diagnostic and Production Animal Medicine College of Veterinary MedicineIowa State University 1600 SE 16th Street Ames IA 50011 USA

Correspondence should be addressed to Kate L Hepworth-Warren katelhepworthgmailcom

Received 23 April 2014 Accepted 11 June 2014 Published 16 June 2014

Academic Editor Nektarios D Giadinis

Copyright copy 2014 Kate L Hepworth-Warren et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Corynebacterium pseudotuberculosis biovar equi is the causative agent of ldquopigeon feverrdquo or ldquodryland distemperrdquo in horsesThe agentis typically identified in theWesternUnited States but has recently been identified inCanada it has not previously been documentedas cause of infection in horses in IowaThis report describes the clinical findings of two horses in Iowa that presented with pectoralabscessation confirmed in one to be C pseudotuberculosis biovar equi

1 Introduction

Corynebacterium pseudotuberculosis biovar equi is the causa-tive agent of ldquopigeon feverrdquo or ldquodryland distemperrdquo in horsesThe classic presentation involves focal pectoral abscessationalthough internal abscessation and ulcerative lymphangitisalso occur Rare reports of other presentations of C pseu-dotuberculosis biovar equi infection have been documentedincluding axillary and tricep muscle infection osteomyelitisseptic arthritis diffuse lymphangitis otitis mediainterna andsecondarymeningitis pericarditis and pleuritis facial celluli-tis and panniculitis [1ndash5] Corynebacterium pseudotubercu-losis biovar equi is a gram positive pleomorphic facultativeintracellular bacterium that is vectored by flying insects Itis typically identified in the western part of the Unites Stateswith the majority of reports coming from California and hasrecently been identified in Canada it has not previously beendocumented in horses in Iowa [6] This report describes twohorses from the same facility that were native to Iowa anddeveloped pectoral abscessation inNovember 2013 A sampleof purulent material from a pectoral abscess of one of thehorses was cultured and pure growth of C pseudotuberculosisbiovar equi was isolated

2 Case Descriptions

The horses in this report were pasture mates housed with twoadditional horses None of the horses in the herd had anyhistory of travel outside of Iowa or contact with animals thathad been outside of the state There was no other livestockon the property although the neighboring property housedcattle that had originated in Colorado

Case 1 was a 16-year-old Paint gelding that presentedto the Iowa State University Field Services with a 4-dayhistory of focal swelling in the right pectoral region Asidefrom the swelling no other clinical signs such as feverlethargy or anorexia had been observed by the ownerPhysical examination was unremarkable with the excep-tion of a firm painful swelling 12minus15 cm in diameter inthe right pectoral region Ultrasonographic examinationrevealed a pocket of hypoechoic fluid 5 cm deep to theskin which was 2 cm in diameter The area was asepticallyprepared and locally anesthetized and aspiration revealeda cream colored tenacious purulent fluid Cytology andGram staining of this sample identified a large number ofneutrophils with a few gram positive bacteria noted Cultureisolated and identified a pure isolate of Corynebacterium

Hindawi Publishing CorporationCase Reports in Veterinary MedicineVolume 2014 Article ID 436287 3 pageshttpdxdoiorg1011552014436287

2 Case Reports in Veterinary Medicine

pseudotuberculosis biovar equi The following day the patientpresented to the Lloyd Veterinary Medical Center where theabscess was incised and drained The patient was prescribed10 days sulfamethoxazole and trimethoprim (30mgkg PO q12 hours) in accordance with antimicrobial susceptibility ofthe isolate and discharged The owner was given instructionsto keep the wounds clean and to avoid contact with outsidehorses until the wounds had healed

Case 2 was a 16-year-old Quarter Horse mare thatdeveloped a focal pectoral swelling two days after Case 1 Atinitial examination in the field a firm hot painful swellingwas noted in the right pectoralmuscle that was approximately5 cm in diameter A plaque of pitting edema was also noted tothe right of midline on the ventral abdomenThe patient wasreferred to the LloydVeterinaryMedical Center the followingday for further evaluation Ultrasonographic examinationidentified a small pocket of hypoechoic fluid within theright pectoral region The ventral plaque of edema wasmarkedly reduced in size at this time and ultrasound didnot identify any pockets of fluid within the swelling Thisright pectoral region was prepared aseptically and followinglocal anesthesia the abscess was incised and drained Initialaspiration did not yield a diagnostic sample thus culturewas not performed Sulfamethoxazole and trimethoprim(30mgkg PO q 12 hours) were prescribed for 10 days on thebasis of a presumptive diagnosis of infection with the sameisolate as Case 1 Communication with the owner 3 monthslater revealed that both horsesrsquo incisions had healed well andthe animals had not developed any additional abscess WhileC pseudotuberculosis biovar equi was not confirmed in Case2 the clinical presentation and timing in conjunction withCase 1 led to a presumptive diagnosis in this case Neitherof the other two horses housed in the property developedevidence of abscessation in this time frame

3 Discussion

This report documents the first clinical case of pigeon feveridentified in a horse in Iowa Corynebacterium pseudotuber-culosis biovar equi has been isolated from horses in statessurrounding Iowa including Missouri South Dakota andNebraska but infection has not previously been documentedin Iowa (Sharon Spier personal communication) A searchof records of the Bacteriology Section of the VeterinaryDiagnostic Laboratory at Iowa State University found twoadditional equine samples from which C pseudotuberculosisbiovar equi had been isolated Interestingly one of thesesamples was submitted during the same year as the casesdescribed here the other in 2005 Complete details from thesecases were not available thus it is unknown if clinical signsconsistent with pigeon fever were present

Corynebacterium pseudotuberculosis biovar equi is highlysuspected to be transmitted via insects of whichHaematobiairritans Musca domestica and Stomoxys calcitrans have beenspecifically identified as carriers of the bacteria all threeof these species of flies are native to Iowa (Ken Holscherpersonal communication Department of Entomology IowaState University) [7] A study in 1998 found that owner-perceived problems with insect control and the use of insect

control were significantly associated with risk of diseasefrom C pseudotuberculosis biovar equi [8] The owner of thetwo horses described here did comment that these horseshad a tendency to have more flies on them than otherhorses although the species of flies are unknown Given theproximity to cattle at an adjacent property H irritans andM domesticawere considered likely vectors Additionally thecattle had been transported from Colorado to Iowa poten-tially acting as fomites and carryingC pseudotuberculosis intocentral Iowa

In California the highest incidence of infection withC pseudotuberculosis biovar equi is found in SeptemberOctober and November with this case occurring within thissame time frame [1] Another group found that the highestfrequency of case detection was in November and Januaryalthough this pertained specifically to horses with internalinfections [9] Interestingly infections in endemic areas tendto occur with higher prevalence followingmonths with heavyrainfall whereas drought conditions were present for muchof 2013 in Iowa [10] In a 2012 study Spier et al found that Cpseudotuberculosis biovar equi survived for at least 8 monthsin soil and growth was better supported in sandy and rockysoil types in comparison to silty soil [11]

In conclusion epidemiological studies have suggestedthat C pseudotuberculosis biovar equi may be more widelyspread than initially thought [12 13] This report docu-ments equine C pseudotuberculosis biovar equi infection inone horse and likely its pasture mate in central Iowa astate in which pigeon fever is previously undocumentedIdentification of agents not native to specific regions ofpractice highlights the importance of sampling abscesses andculturing purulent material

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] M Aleman S J Spier W D Wilson and M DoherrldquoCorynebacterium pseudotuberculosis infection in horses 538cases (1982ndash1993)rdquo Journal of the American Veterinary MedicalAssociation vol 209 no 4 pp 804ndash809 1996

[2] E G Farstvedt D A Hendrickson C E Dickenson and S JSpier ldquoTreatment of suppurative facial cellulitis and panniculitiscaused by Corynebacterium pseudotuberculosis in two horsesrdquoJournal of the AmericanVeterinaryMedical Association vol 224no 7 pp 1139ndash1142 2004

[3] N Nogradi S J Spier B Toth and B Vaughan ldquoMusculoskele-tal Corynebacterium pseudotuberculosis infection in horses 35cases (1999ndash2009)rdquo Journal of the American Veterinary MedicalAssociation vol 241 no 6 pp 771ndash777 2012

[4] S L Perkins K G Magdesian W P Thomas and S J SpierldquoPericarditis and pleuritis caused by Corynebacterium pseu-dotuberculosis in a horserdquo Journal of the American VeterinaryMedical Association vol 224 no 7 pp 1133ndash1138 2004

Case Reports in Veterinary Medicine 3

[5] C L Rand T L Hall M Aleman and S J Spier ldquoOtitis media-interna and secondary meningitis associated with Corynebac-terium pseudotuberculosis infection in a horserdquo Equine Veteri-nary Education vol 24 no 6 pp 271ndash275 2012

[6] httpwwwpromedmailorg[7] S J Spier C M Leutenegger M Vet et al ldquoUse of a real-

time polymerase chain reaction-based fluorogenic 51015840 nucleaseassay to evaluate insect vectors of Corynebacterium pseudotu-berculosis infections in horsesrdquo American Journal of VeterinaryResearch vol 65 no 6 pp 829ndash834 2004

[8] M G Doherr T E Carpenter K M P Hanson W D Wilsonand I A Gardner ldquoRisk factors associated with Corynebac-terium pseudotuberculosis infection in California horsesrdquo Pre-ventive Veterinary Medicine vol 35 no 4 pp 229ndash239 1998

[9] SM Pratt S J Spier S P Carroll B VaughanM BWhitcomband W D Wilson ldquoEvaluation of clinical characteristics diag-nostic test results and outcome in horses with internal infectioncaused by Corynebacterium pseudotuberculosis 30 cases (1995ndash2003)rdquo Journal of the American Veterinary Medical Associationvol 227 no 3 pp 441ndash448 2005

[10] K CMiers andW B Ley ldquoCorynebacterium pseudotuberculosisinfection in the horse study of 117 clinical cases and consider-ation of etiopathogenesisrdquo Journal of the American VeterinaryMedical Association vol 177 no 3 pp 250ndash253 1980

[11] S J Spier B Toth J Edman et al ldquoShort communicationssurvival of Corynebacterium pseudotuberculosis biovar equi insoilrdquo Veterinary Record vol 170 no 7 p 180 2012

[12] J E Foley S J Spier J Mihalyi N Drazenovich and C MLeutenegger ldquoMolecular epidemiologic features of Corynebac-terium pseudotuberculosis isolated from horsesrdquoAmerican Jour-nal of Veterinary Research vol 65 no 12 pp 1734ndash1737 2004

[13] K Hall B J McCluskey and W Cunningham ldquoCorynebac-terium pseudotuberculosis infections (pigeon fever) in horses inWestern Colorado an epidemiological investigationrdquo Journal ofEquine Veterinary Science vol 21 no 6 pp 284ndash286 2001

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Case Reports in Veterinary Medicine

2 Case Reports in Veterinary Medicine

pseudotuberculosis biovar equi The following day the patientpresented to the Lloyd Veterinary Medical Center where theabscess was incised and drained The patient was prescribed10 days sulfamethoxazole and trimethoprim (30mgkg PO q12 hours) in accordance with antimicrobial susceptibility ofthe isolate and discharged The owner was given instructionsto keep the wounds clean and to avoid contact with outsidehorses until the wounds had healed

Case 2 was a 16-year-old Quarter Horse mare thatdeveloped a focal pectoral swelling two days after Case 1 Atinitial examination in the field a firm hot painful swellingwas noted in the right pectoralmuscle that was approximately5 cm in diameter A plaque of pitting edema was also noted tothe right of midline on the ventral abdomenThe patient wasreferred to the LloydVeterinaryMedical Center the followingday for further evaluation Ultrasonographic examinationidentified a small pocket of hypoechoic fluid within theright pectoral region The ventral plaque of edema wasmarkedly reduced in size at this time and ultrasound didnot identify any pockets of fluid within the swelling Thisright pectoral region was prepared aseptically and followinglocal anesthesia the abscess was incised and drained Initialaspiration did not yield a diagnostic sample thus culturewas not performed Sulfamethoxazole and trimethoprim(30mgkg PO q 12 hours) were prescribed for 10 days on thebasis of a presumptive diagnosis of infection with the sameisolate as Case 1 Communication with the owner 3 monthslater revealed that both horsesrsquo incisions had healed well andthe animals had not developed any additional abscess WhileC pseudotuberculosis biovar equi was not confirmed in Case2 the clinical presentation and timing in conjunction withCase 1 led to a presumptive diagnosis in this case Neitherof the other two horses housed in the property developedevidence of abscessation in this time frame

3 Discussion

This report documents the first clinical case of pigeon feveridentified in a horse in Iowa Corynebacterium pseudotuber-culosis biovar equi has been isolated from horses in statessurrounding Iowa including Missouri South Dakota andNebraska but infection has not previously been documentedin Iowa (Sharon Spier personal communication) A searchof records of the Bacteriology Section of the VeterinaryDiagnostic Laboratory at Iowa State University found twoadditional equine samples from which C pseudotuberculosisbiovar equi had been isolated Interestingly one of thesesamples was submitted during the same year as the casesdescribed here the other in 2005 Complete details from thesecases were not available thus it is unknown if clinical signsconsistent with pigeon fever were present

Corynebacterium pseudotuberculosis biovar equi is highlysuspected to be transmitted via insects of whichHaematobiairritans Musca domestica and Stomoxys calcitrans have beenspecifically identified as carriers of the bacteria all threeof these species of flies are native to Iowa (Ken Holscherpersonal communication Department of Entomology IowaState University) [7] A study in 1998 found that owner-perceived problems with insect control and the use of insect

control were significantly associated with risk of diseasefrom C pseudotuberculosis biovar equi [8] The owner of thetwo horses described here did comment that these horseshad a tendency to have more flies on them than otherhorses although the species of flies are unknown Given theproximity to cattle at an adjacent property H irritans andM domesticawere considered likely vectors Additionally thecattle had been transported from Colorado to Iowa poten-tially acting as fomites and carryingC pseudotuberculosis intocentral Iowa

In California the highest incidence of infection withC pseudotuberculosis biovar equi is found in SeptemberOctober and November with this case occurring within thissame time frame [1] Another group found that the highestfrequency of case detection was in November and Januaryalthough this pertained specifically to horses with internalinfections [9] Interestingly infections in endemic areas tendto occur with higher prevalence followingmonths with heavyrainfall whereas drought conditions were present for muchof 2013 in Iowa [10] In a 2012 study Spier et al found that Cpseudotuberculosis biovar equi survived for at least 8 monthsin soil and growth was better supported in sandy and rockysoil types in comparison to silty soil [11]

In conclusion epidemiological studies have suggestedthat C pseudotuberculosis biovar equi may be more widelyspread than initially thought [12 13] This report docu-ments equine C pseudotuberculosis biovar equi infection inone horse and likely its pasture mate in central Iowa astate in which pigeon fever is previously undocumentedIdentification of agents not native to specific regions ofpractice highlights the importance of sampling abscesses andculturing purulent material

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] M Aleman S J Spier W D Wilson and M DoherrldquoCorynebacterium pseudotuberculosis infection in horses 538cases (1982ndash1993)rdquo Journal of the American Veterinary MedicalAssociation vol 209 no 4 pp 804ndash809 1996

[2] E G Farstvedt D A Hendrickson C E Dickenson and S JSpier ldquoTreatment of suppurative facial cellulitis and panniculitiscaused by Corynebacterium pseudotuberculosis in two horsesrdquoJournal of the AmericanVeterinaryMedical Association vol 224no 7 pp 1139ndash1142 2004

[3] N Nogradi S J Spier B Toth and B Vaughan ldquoMusculoskele-tal Corynebacterium pseudotuberculosis infection in horses 35cases (1999ndash2009)rdquo Journal of the American Veterinary MedicalAssociation vol 241 no 6 pp 771ndash777 2012

[4] S L Perkins K G Magdesian W P Thomas and S J SpierldquoPericarditis and pleuritis caused by Corynebacterium pseu-dotuberculosis in a horserdquo Journal of the American VeterinaryMedical Association vol 224 no 7 pp 1133ndash1138 2004


















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Volume 2014

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InsectsJournal of




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case report isolation of corynebacterium...

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