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McDougall FK, Boardman WS, Speight N, Stephenson T, Funnell O, Smith I, Graham PL, Power ML. Carriage of antibiotic resistance genes to treatments for chlamydial disease in koalas ( Phascolarctos cinereus): A comparison of occurrence before and during catastrophic wildfires. One Health 2023; 17:100652. [PMID: 38024267 PMCID: PMC10665209 DOI: 10.1016/j.onehlt.2023.100652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/07/2023] [Indexed: 12/01/2023] Open
Abstract
Growing reports of diverse antibiotic resistance genes in wildlife species around the world symbolises the extent of this global One Health issue. The health of wildlife is threatened by antimicrobial resistance in situations where wildlife species develop disease and require antibiotics. Chlamydial disease is a key threat for koalas in Australia, with infected koalas frequently entering wildlife hospitals and requiring antibiotic therapy, typically with chloramphenicol or doxycycline. This study investigated the occurrence and diversity of target chloramphenicol and doxycycline resistance genes (cat and tet respectively) in koala urogenital and faecal microbiomes. DNA was extracted from 394 urogenital swabs and 91 faecal swabs collected from koalas in mainland Australia and on Kangaroo Island (KI) located 14 km off the mainland, before (n = 145) and during (n = 340) the 2019-2020 wildfires. PCR screening and DNA sequencing determined 9.9% of samples (95%CI: 7.5% to 12.9%) carried cat and/or tet genes, with the highest frequency in fire-affected KI koalas (16.8%) and the lowest in wild KI koalas sampled prior to fires (6.5%). The diversity of cat and tet was greater in fire-affected koalas (seven variants detected), compared to pre-fire koalas (two variants detected). Fire-affected koalas in care that received antibiotics had a significantly higher proportion (p < 0.05) of cat and/or tet genes (37.5%) compared to koalas that did not receive antibiotics (9.8%). Of the cat and/or tet positive mainland koalas, 50.0% were Chlamydia-positive by qPCR test. Chloramphenicol and doxycycline resistance genes in koala microbiomes may contribute to negative treatment outcomes for koalas receiving anti-chlamydial antibiotics. Thus a secondary outcome of wildfires is increased risk of acquisition of cat and tet genes in fire-affected koalas that enter care, potentially exacerbating the already significant threat of chlamydial disease on Australia's koalas. This study highlights the importance of considering impacts to wildlife health within the One Health approach to AMR and identifies a need for greater understanding of AMR ecology in wildlife.
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Affiliation(s)
- Fiona K. McDougall
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia
| | - Wayne S.J. Boardman
- School of Animal and Veterinary Sciences, Faculty of Sciences, Engineering and Technology, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Natasha Speight
- School of Animal and Veterinary Sciences, Faculty of Sciences, Engineering and Technology, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Tamsyn Stephenson
- School of Animal and Veterinary Sciences, Faculty of Sciences, Engineering and Technology, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Oliver Funnell
- Zoos South Australia, Frome Rd, Adelaide, SA 5001, Australia
| | - Ian Smith
- School of Animal and Veterinary Sciences, Faculty of Sciences, Engineering and Technology, University of Adelaide, Roseworthy, SA 5371, Australia
- Zoos South Australia, Frome Rd, Adelaide, SA 5001, Australia
| | - Petra L. Graham
- School of Mathematical and Physical Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia
| | - Michelle L. Power
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia
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Peel E, Cheng Y, Djordjevic JT, O’Meally D, Thomas M, Kuhn M, Sorrell TC, Huston WM, Belov K. Koala cathelicidin PhciCath5 has antimicrobial activity, including against Chlamydia pecorum. PLoS One 2021; 16:e0249658. [PMID: 33852625 PMCID: PMC8046226 DOI: 10.1371/journal.pone.0249658] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/22/2021] [Indexed: 11/18/2022] Open
Abstract
Devastating fires in Australia over 2019-20 decimated native fauna and flora, including koalas. The resulting population bottleneck, combined with significant loss of habitat, increases the vulnerability of remaining koala populations to threats which include disease. Chlamydia is one disease which causes significant morbidity and mortality in koalas. The predominant pathogenic species, Chlamydia pecorum, causes severe ocular, urogenital and reproductive tract disease. In marsupials, including the koala, gene expansions of an antimicrobial peptide family known as cathelicidins have enabled protection of immunologically naïve pouch young during early development. We propose that koala cathelicidins are active against Chlamydia and other bacteria and fungi. Here we describe ten koala cathelicidins, five of which contained full length coding sequences that were widely expressed in tissues throughout the body. Focusing on these five, we investigate their antimicrobial activity against two koala C. pecorum isolates from distinct serovars; MarsBar and IPTaLE, as well as other bacteria and fungi. One cathelicidin, PhciCath5, inactivated C. pecorum IPTaLE and MarsBar elementary bodies and significantly reduced the number of inclusions compared to the control (p<0.0001). Despite evidence of cathelicidin expression within tissues known to be infected by Chlamydia, natural PhciCath5 concentrations may be inadequate in vivo to prevent or control C. pecorum infections in koalas. PhciCath5 also displayed antimicrobial activity against fungi and Gram negative and positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Electrostatic interactions likely drive PhciCath5 adherence to the pathogen cell membrane, followed by membrane permeabilisation leading to cell death. Activity against E. coli was reduced in the presence of 10% serum and 20% whole blood. Future modification of the PhciCath5 peptide to enhance activity, including in the presence of serum/blood, may provide a novel solution to Chlamydia infection in koalas and other species.
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Affiliation(s)
- Emma Peel
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Yuanyuan Cheng
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Julianne T. Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead, New South Wales, Australia
| | - Denis O’Meally
- Center for Gene Therapy, Beckman Research Institute of the City of Hope, Duarte, California, United States of America
| | - Mark Thomas
- School of Life Sciences, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Michael Kuhn
- Zoetis, Veterinary Medicine Research and Development, Kalamazoo, Michigan, United States of America
| | - Tania C. Sorrell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead, New South Wales, Australia
| | - Wilhelmina M. Huston
- School of Life Sciences, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Katherine Belov
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
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Quigley BL, Timms P. Helping koalas battle disease - Recent advances in Chlamydia and koala retrovirus (KoRV) disease understanding and treatment in koalas. FEMS Microbiol Rev 2020; 44:583-605. [PMID: 32556174 PMCID: PMC8600735 DOI: 10.1093/femsre/fuaa024] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/14/2020] [Indexed: 12/31/2022] Open
Abstract
The iconic Australian marsupial, the koala (Phascolarctos cinereus), has suffered dramatic population declines as a result of habitat loss and fragmentation, disease, vehicle collision mortality, dog attacks, bushfires and climate change. In 2012, koalas were officially declared vulnerable by the Australian government and listed as a threatened species. In response, research into diseases affecting koalas has expanded rapidly. The two major pathogens affecting koalas are Chlamydia pecorum, leading to chlamydial disease and koala retrovirus (KoRV). In the last eight years, these pathogens and their diseases have received focused study regarding their sources, genetics, prevalence, disease presentation and transmission. This has led to vast improvements in pathogen detection and treatment, including the ongoing development of vaccines for each as a management and control strategy. This review will summarize and highlight the important advances made in understanding and combating C. pecorum and KoRV in koalas, since they were declared a threatened species. With complementary advances having also been made from the koala genome sequence and in our understanding of the koala immune system, we are primed to make a significant positive impact on koala health into the future.
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Affiliation(s)
- Bonnie L Quigley
- Genecology Research Centre, University of the Sunshine Coast,
90 Sippy Downs Drive, Sippy Downs, Queensland, 4556, Australia
| | - Peter Timms
- Genecology Research Centre, University of the Sunshine Coast,
90 Sippy Downs Drive, Sippy Downs, Queensland, 4556, Australia
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Nyari S, Booth R, Quigley BL, Waugh CA, Timms P. Therapeutic effect of a Chlamydia pecorum recombinant major outer membrane protein vaccine on ocular disease in koalas (Phascolarctos cinereus). PLoS One 2019; 14:e0210245. [PMID: 30615687 PMCID: PMC6322743 DOI: 10.1371/journal.pone.0210245] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 12/19/2018] [Indexed: 12/29/2022] Open
Abstract
Chlamydia pecorum is responsible for causing ocular infection and disease which can lead to blindness in koalas (Phascolarctos cinereus). Antibiotics are the current treatment for chlamydial infection and disease in koalas, however, they can be detrimental for the koala’s gastrointestinal tract microbiota and in severe cases, can lead to dysbiosis and death. In this study, we evaluated the therapeutic effects provided by a recombinant chlamydial major outer membrane protein (MOMP) vaccine on ocular disease in koalas. Koalas with ocular disease (unilateral or bilateral) were vaccinated and assessed for six weeks, evaluating any changes to the conjunctival tissue and discharge. Samples were collected pre- and post-vaccination to evaluate both humoral and cell-mediated immune responses. We further assessed the infecting C. pecorum genotype, host MHC class II alleles and presence of koala retrovirus type (KoRV-B). Our results clearly showed an improvement in the clinical ocular disease state of all seven koalas, post-vaccination. We observed increases in ocular mucosal IgA antibodies to whole C. pecorum elementary bodies, post-vaccination. We found that systemic cell-mediated immune responses to interferon-γ, interleukin-6 and interleukin-17A were not significantly predictive of ocular disease in koalas. Interestingly, one koala did not have as positive a clinical response (in one eye primarily) and this koala was infected with a C. pecorum genotype (E’) that was not used as part of the vaccine formula (MOMP genotypes A, F and G). The predominant MHC class II alleles identified were DAb*19, DAb*21 and DBb*05, with no two koalas identified with the same genetic sequence. Additionally, KoRV-B, which is associated with chlamydial disease outcome, was identified in two (29%) ocular diseased koalas, which still produced vaccine-induced immune responses and clinical ocular improvements post-vaccination. Our findings show promise for the use of a recombinant chlamydial MOMP vaccine for the therapeutic treatment of ocular disease in koalas.
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Affiliation(s)
- Sharon Nyari
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Rosemary Booth
- Australia Zoo Wildlife Hospital, Beerwah, Queensland, Australia
| | - Bonnie L. Quigley
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Courtney A. Waugh
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Peter Timms
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- * E-mail:
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Nyari S, Khan SA, Rawlinson G, Waugh CA, Potter A, Gerdts V, Timms P. Vaccination of koalas (Phascolarctos cinereus) against Chlamydia pecorum using synthetic peptides derived from the major outer membrane protein. PLoS One 2018; 13:e0200112. [PMID: 29953523 PMCID: PMC6023247 DOI: 10.1371/journal.pone.0200112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/18/2018] [Indexed: 11/18/2022] Open
Abstract
Chlamydia pecorum is a mucosal infection, which causes debilitating disease of the urinary tract, reproductive tract and ocular sites of koalas (Phascolarctos cinereus). While antibiotics are available for treatment, they are detrimental to the koalas' gastrointestinal tract microflora leaving the implementation of a vaccine as an ideal option for the long-term management of koala populations. We have previously reported on the successes of an anti-chlamydial recombinant major outer membrane protein (rMOMP) vaccine however, recombinant protein based vaccines are not ideal candidates for scale up from the research level to small-medium production level for wider usage. Peptide based vaccines are a promising area for vaccine development, because peptides are stable, cost effective and easily produced. In this current study, we assessed, for the first time, the immune responses to a synthetic peptide based anti-chlamydial vaccine in koalas. Five healthy male koalas were vaccinated with two synthetic peptides derived from C. pecorum MOMP and another five healthy male koalas were vaccinated with full length recombinant C. pecorum MOMP (genotype G). Systemic (IgG) and mucosal (IgA) antibodies were quantified and pre-vaccination levels compared to post-vaccination levels (12 and 26 weeks). MOMP-peptide vaccinated koalas produced Chlamydia-specific IgG and IgA antibodies, which were able to recognise not only the genotype used in the vaccination, but also MOMPs from several other koala C. pecorum genotypes. In addition, IgA antibodies induced at the ocular site not only recognised recombinant MOMP protein but also, whole native chlamydial elementary bodies. Interestingly, some MOMP-peptide vaccinated koalas showed a stronger and more sustained vaccine-induced mucosal IgA antibody response than observed in MOMP-protein vaccinated koalas. These results demonstrate that a synthetic MOMP peptide based vaccine is capable of inducing a Chlamydia-specific antibody response in koalas and is a promising candidate for future vaccine development.
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Affiliation(s)
- Sharon Nyari
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Shahneaz Ali Khan
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Galit Rawlinson
- Lone Pine Koala Sanctuary, Fig Tree Pocket, Queensland, Australia
| | - Courtney A. Waugh
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Andrew Potter
- Vaccine and Infectious Disease Organisation–International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, Canada
| | - Volker Gerdts
- Vaccine and Infectious Disease Organisation–International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, Canada
| | - Peter Timms
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- * E-mail:
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Budd C, Flanagan C, Gillett A, Hanger J, Loader JJ, Govendir M. Assessment of florfenicol as a possible treatment for chlamydiosis in koalas (Phascolarctos cinereus). Aust Vet J 2017; 95:343-349. [PMID: 28845567 DOI: 10.1111/avj.12617] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 10/07/2016] [Accepted: 11/08/2016] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Because of limited availability of chloramphenicol to veterinary suppliers, a preliminary study was performed to predict whether an analogue, florfenicol, is an efficacious treatment for chlamydiosis in koalas. METHODS Florfenicol was administered to koalas with naturally occurring chlamydiosis at 20 mg/kg SC (n = 3) and at 5 mg/kg (n = 3) and 10 mg/kg (n = 3) IV. The estimated areas under the plasma concentration versus time curves (AUC) were compared with the minimum inhibitory concentration to inhibit Chlamydia pecorum. Clinical data were also examined from field trials conducted on koalas (n = 19) with naturally occurring chlamydiosis and treated with florfenicol at a range of dosages (5-20 mg/kg SC and 6-15 mg/kg IV). Florfenicol binding to proteins in plasma was also determined. RESULTS Florfenicol was not detectable in plasma 24 h post-administration at 20 mg/kg SC. The estimated AUC0-24 h following administration at 10 mg/kg IV suggests florfenicol might be effective against Chlamydia spp. via this route. Florfenicol binding to plasma proteins was 13.0% (± 0.30 SEM). After treatment with florfenicol in field trials, 5 of 19 koalas (26%) were released without further treatment, 4 with no long-term follow-up; 6 (32%) required additional treatment with chloramphenicol to resolve chlamydiosis; 7 (36%) failed to clinically improve, of which 3 had clinical signs and/or necropsy findings suggestive of antibiotic-related gastrointestinal dysbiosis; another koala died within minutes of florfenicol administered IV at 7 mg/kg. CONCLUSION When administered at dosages tolerable in the field, florfenicol is a problematic treatment for chlamydiosis based on equivocal outcomes and plasma concentrations below those that inhibit the pathogen.
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Affiliation(s)
- C Budd
- Sydney School of Veterinary Science The University of Sydney, Sydney, New South Wales, Australia
| | - C Flanagan
- Port Macquarie Koala Hospital, Port Macquarie, New South Wales, Australia
| | - A Gillett
- Australia Zoo Wildlife Hospital, Beerwah, Queensland, Australia
| | - J Hanger
- Endeavour Veterinary Ecology, Toorbul, Queensland, Australia
| | - J J Loader
- Endeavour Veterinary Ecology, Toorbul, Queensland, Australia
| | - M Govendir
- Sydney School of Veterinary Science The University of Sydney, Sydney, New South Wales, Australia
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Govendir M. Review of some pharmacokinetic and pharmacodynamic properties of anti-infective medicines administered to the koala (Phascolarctos cinereus). J Vet Pharmacol Ther 2017; 41:1-10. [PMID: 28703410 DOI: 10.1111/jvp.12435] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/04/2017] [Indexed: 01/12/2023]
Abstract
Although koalas are iconic Australian animals, no pharmacokinetic studies of any first-line medicines used to treat diseased or injured koalas had been published prior to 2010. Traditionally, medicine dosages suggested for this species underwent linear extrapolation from those recommended for domesticated species. The koala, a specialist folivore whose natural diet consists of almost exclusively Eucalyptus spp. foliage has anatomical and physiological adaptations for detoxifying their diet which also affect medicine pharmacokinetic profiles. This review addresses aspects of medicine absorption, clearance, and other indices (such as medicine binding to plasma proteins) of enrofloxacin/marbofloxacin and chloramphenicol used for the systemic treatment of chlamydiosis, and fluconazole ± amphotericin, and posaconazole for the treatment of cryptococcosis. Based on observations from published studies, this review includes suggestions to improve therapeutic outcomes when administering medicines to diseased koalas.
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Affiliation(s)
- M Govendir
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
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Lawrence A, Fraser T, Gillett A, Tyndall JDA, Timms P, Polkinghorne A, Huston WM. Chlamydia Serine Protease Inhibitor, targeting HtrA, as a New Treatment for Koala Chlamydia infection. Sci Rep 2016; 6:31466. [PMID: 27530689 PMCID: PMC4987629 DOI: 10.1038/srep31466] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/20/2016] [Indexed: 01/01/2023] Open
Abstract
The koala, an iconic marsupial native to Australia, is a threatened species in many parts of the country. One major factor in the decline is disease caused by infection with Chlamydia. Current therapeutic strategies to treat chlamydiosis in the koala are limited. This study examines the effectiveness of an inhibitor, JO146, which targets the HtrA serine protease for treatment of C. pecorum and C. pneumoniae in vitro and ex vivo with the aim of developing a novel therapeutic for koala Chlamydia infections. Clinical isolates from koalas were examined for their susceptibility to JO146. In vitro studies demonstrated that treatment with JO146 during the mid-replicative phase of C. pecorum or C. pneumoniae infections resulted in a significant loss of infectious progeny. Ex vivo primary koala tissue cultures were used to demonstrate the efficacy of JO146 and the non-toxic nature of this compound on peripheral blood mononuclear cells and primary cell lines established from koala tissues collected at necropsy. Our results suggest that inhibition of the serine protease HtrA could be a novel treatment strategy for chlamydiosis in koalas.
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Affiliation(s)
- Amba Lawrence
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, 4059, Australia
| | - Tamieka Fraser
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydoore, QLD, 4558, Australia
| | - Amber Gillett
- Australia Zoo Wildlife Hospital, Beerwah, QLD, 4519, Australia
| | - Joel D A Tyndall
- New Zealand's National School of Pharmacy, University of Otago, Dunedin 9054 New Zealand
| | - Peter Timms
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydoore, QLD, 4558, Australia
| | - Adam Polkinghorne
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydoore, QLD, 4558, Australia
| | - Wilhelmina M Huston
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, 4059, Australia.,School of Life Sciences, University of Technology Sydney, Broadway, NSW, 2007, Australia
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Black LA, Higgins DP, Govendir M. In vitro activity of chloramphenicol, florfenicol and enrofloxacin against Chlamydia pecorum isolated from koalas (Phascolarctos cinereus). Aust Vet J 2015; 93:420-3. [PMID: 26412342 DOI: 10.1111/avj.12364] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 04/12/2015] [Accepted: 05/04/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To determine the in vitro susceptibilities of koala isolates of Chlamydia pecorum to enrofloxacin and chloramphenicol, which are frequently used to treat koalas with chlamydiosis, and florfenicol, a derivative of chloramphenicol. METHODS The in vitro susceptibilities were determined by culturing three stored isolates and seven clinical swabs of C. pecorum. Susceptibility testing was undertaken using cycloheximide-treated buffalo green monkey kidney cells in 96 well microtitre plates. RESULTS The minimum inhibitory concentrations (MICs) for all isolates were 0.25-0.50 µg/mL (enrofloxacin), 1-2 µg/mL (chloramphenicol), and 1-2 µg/mL (florfenicol). Minimum bactericidal concentration (MBC) values for five isolates were also determined and were within one two-fold dilution of MICs. The MICs and MBCs of these antimicrobials were within ranges previously reported for other chlamydial species. CONCLUSION When combined with previously published pharmacokinetic data, the in vitro susceptibility results support chloramphenicol as a more appropriate treatment option than enrofloxacin for koalas with chlamydiosis. The susceptibility results also indicate florfenicol may be an appropriate treatment option for koalas with chlamydiosis, warranting further investigation.
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Affiliation(s)
- L A Black
- McMaster Building B14, Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia
| | - D P Higgins
- McMaster Building B14, Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia
| | - M Govendir
- McMaster Building B14, Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia.
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Scheelings TF, Devi JL, Woodward AP, Whittem T. Pharmacokinetics of enrofloxacin following oral and subcutaneous administration in the common ringtail possum (Pseudocheirus peregrinus). J Vet Pharmacol Ther 2015; 38:482-7. [PMID: 25622984 DOI: 10.1111/jvp.12201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/11/2014] [Indexed: 11/26/2022]
Abstract
[Correction added on 23 March 2015, after first online publication: Terminal half-life values of enrofloxacin is corrected in the fourth sentence of the abstract] Clinically healthy common ringtail possums (n = 5) received single doses of 10 mg/kg enrofloxacin orally and then 2 weeks later subcutaneously. Serial plasma samples were collected over 24 h for each treatment phase, and enrofloxacin concentrations were determined using a validated HPLC assay. Pharmacokinetic parameters were determined by noncompartmental analysis. Following oral administration, plasma concentrations were of therapeutic relevance (Cmax median 5.45 μg/mL, range 2.98-6.9 μg/mL), with terminal-phase half-life (t½ ) shorter than in other species (median 3.09 h, range 1.79-5.30 h). In contrast, subcutaneous administration of enrofloxacin did not achieve effective plasma concentrations, with plasma concentrations too erratic to fit the noncompartmental model except in one animal. On the basis of the AUC:MIC, enrofloxacin administered at 10 mg/kg orally, but not subcutaneously, is likely to be effective against a range of bacterial species that have been reported in common ringtail possums.
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Affiliation(s)
- T F Scheelings
- Australian Wildlife Health Centre, Healesville Sanctuary, Healesville, Vic., Australia
| | - J L Devi
- Translational Research and Animal Clinical Trial Study (TRACTS) Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Vic., Australia
| | - A P Woodward
- Translational Research and Animal Clinical Trial Study (TRACTS) Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Vic., Australia
| | - T Whittem
- Translational Research and Animal Clinical Trial Study (TRACTS) Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Vic., Australia
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12
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Gastrointestinal torsions and intussusception in northern koalas (Phascolarctos cinereus) at San Diego Zoo (1976-2012). J Zoo Wildl Med 2014; 45:118-26. [PMID: 24712170 DOI: 10.1638/2012-0182r.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The recent classification as threatened status of the northern koala (Phascolarctos cinereus) by the Australian Government highlights the importance of the conservation and health management of this iconic Australian marsupial. This case series describes gastrointestinal torsion and intussusception in six northern koalas (three males, three females, 2-11 yr old) at the San Diego Zoo from 1976 to 2012. Two koalas died shortly after presentation. Diagnoses of ileocecal intussusception, resulting from enteritis in one case and cecal torsion in the other, were made at postmortem examination. One koala died 4 days after an exploratory laparotomy, with negative findings, and an acute double colonic intussusception was diagnosed at postmortem examination. Two small intestinal mesenteric torsion and one proximal colon mesenteric torsion cases were successfully corrected surgically. In the case of colonic mesenteric torsion, the koala had recurrent clinical signs 2 wk later, and a second surgery requiring resection and anastomosis of ischemic jejunum was performed, with the koala dying shortly afterward. One koala with small intestinal torsion had a recurrence of torsion 22 mo later and subsequently died. The koala with the second case of small intestinal torsion remains alive 14 mo postsurgical correction. All six koalas presented with signs of colic that included anorexia, lethargy, depression, acute abdominal distension, abdominal stretching, decreased fecal output, open-mouth gasping, or a combination of symptoms. Abdominal radiographs may show stacked gastrointestinal linear gas patterns and contrast stasis. Prevalence of torsion and intussusception is low at this institution (2%), although recurrence in individuals is common (50%) and overall survival is poor (83%), which emphasizes the importance of timely recognition, surgical correction, and postoperative management. While inciting etiologies were unable to be determined in these cases, monitoring generalized gastrointestinal health and differing Eucalyptus sp. effects on individual koala's gastrointestinal function, parasite control, and stress minimization through standardized husbandry practices are likely important.
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