Klebsiella Oxytoca

Klebsiella oxytoca

Agent Gram-negative, facultative anaerobic, non spore-forming rod. Family: Enterobacteriaceae K. oxytoca has not been recognized as a primary pathogen and is a low-level opportunist. FELASA 2014 classes K.oxytoca as an additional agent where testing is optional and should be pursued if there is a specific need.

Hosts All known mammalian species including laboratory rodent and lagomorph species as well as many other vertebrates and invertebrates are susceptible to colonization with Klebsiella. Due to its ability to colonize a wide range of species, Klebsiella can be transmitted from one species to another.

Prevalence Klebsiella are ubiquitous in nature and can be isolated from water, sewage, soil and plants. They are common human and rodent intestinal tract commensals. Rodent colony prevalence may increase with antibiotic treatment, which presumably reduces the beneficial flora and allows Klebsiella overgrowth. Klebsiella spp. are common in laboratory animal facilities.

Transmission Faecal-oral or from direct contact. Klebsiella colonizes the gut preferentially, although it may also be found on the skin and in the nasopharynx.

Clinical signs & pathology Immunocompetent animals usually do not usually display clinical signs. Infection may occur when there is an overgrowth of bacteria due to disruption of the gut flora in immunocompromised rodents. In susceptible animals, clinical signs include poor body condition, rough hair coat, urogenital tract infections, pneumonia, abscesses and otitis media.

Diagnosis PCR (fecal pellets, cage swabs, cecal swab) and culture (faecal, oropharyngeal swabs, lesions). Diagnosis is based on agent isolation or detection in association with lesions that are not necessarily specific for Klebsiella. As Klebsiella oxytoca can be recovered from clinically normal animals, isolation from the gastrointestinal tract, faeces, or in low numbers from mucosal surfaces is insufficient to demonstrate disease.

Prevention and Control Treatment is not recommended and antimicrobials rarely resolve the carrier state nor eliminate bacteria from bedding or caging.

Susceptibility to disinfectants: Gram-negative bacteria are generally susceptible to a number of disinfectants used in animal facilities including phenolic compounds, hypochlorites (1% sodium hypochlorite), alcohols (70% ethanol), formaldehyde (18.5g/L; 5% formalin in water), 2% glutaraldehyde, iodines (0.075g/L) and peroxygen compounds (1% Virkon S).

Physical inactivation: It is sensitive to moist heat (121oC for at least 15 min) and dry heat (160-170oC for at least 1 hour).

Survival outside host. Glass coverslips: 4h

Klebsiella species can develop biofilms that may protect them unless first mechanically disrupted.

Research implications Klebsiella recovery as a component of the normal flora of a healthy laboratory rodent is of low significance. It is an opportunistic agent that may complicate studies where host defences are compromised. If animals are to be used as models of human Gram-negative sepsis or pneumonia with Klebsiella as the inciting organism, they should be free of Klebsiella. Immunodeficient animals, especially those with severe immunodeficiencies, or defects of the innate immune system, may develop clinical disease associated with Klebsiella infection.

References

Barthold,S.W., Griffey, S.M. and Percy, D.H. Pathology of Laboratory Rodents and Rabbits, 4th edition, Blackwell Publishing, 2016 p62,145

Bleich, A., et al., Klebsiella oxytoca: opportunistic infections in laboratory rodents. Lab Anim, 2008. 42(3): p.369-75.

Charles River. 2009. Klebsiella species (K.oxytoca, K.pneumoniae). [ONLINE] Available at https://www.criver.com/sites/default/files/resources/KlebsiellaSpeciesTechnicalSheet.pdf. [Accessed 19 March 2018]

Diseases of Research Animals – DORA University of Missouri – Comparative Medicine Program and IDEXX-BioResearch. 2013. Klebsiella oxytoca. [ONLINE] Available at: http://dora.missouri.edu/mouse/klebsiella-oxytoca/. [Accessed 19 March 2018].

Dupont. 2006. Virkon S [ONLINE] Available at http://alltechlienert.com.au/wp-content/uploads/2015/06/NEW-Virkon-S.pdf. [Accessed 19 March 2018]

Fox, J.G., Anderson,L.C., Otto, G,M., Pritchett-Corning,K.R. & Whary,M.T. Laboratory Animal Medicine, 3rd Edition, Academic Press, 2015 p 115

Fox, J.G., Barthold, S.W., Davisson, M,T., Newcomer, C.E.,Quimby, F.W and Smith, A.L, editors. The Mouse in Biomedical Research: Diseases. 2nd Edition, New York; Academic Press, 2007 pp 379-380

MSDS online- a Velocity EHS solution. 2017. Klebsiella spp [ONLINE] Available at: https://www.msdsonline.com/resources/msds-resources/free-safety-data-sheet-index/klebsiella-spp/.[Accessed 19 March 2019].

Public Health Agency of Canada. 2011. Klebsiella spp [ONLINE] Available at: http://www.phac-aspc.gc.ca/lab-bio/res/psds- ftss/klebsiella-eng.php#footnote8. [Accessed 6 July 2017]