Diagnosis of bacterial infections. Part 1: Principles of sample collection and transportation

Abstract

Summary Bacterial infections are common in equine practice, therefore it is important that diseases caused by these organisms are diagnosed accurately. Collection of appropriate samples in a correct and timely manner is fundamental to determining the causative agent. Furthermore, transportation of samples to the laboratory must ensure that the agents survive and can be identified. This paper outlines a recommended diagnostic approach when bacteria are suspected, the samples that may be obtained in order to confirm their presence, and the transportation requirements to facilitate their isolation in diagnostic laboratories.

Bacteroides sp. as a cause of anaerobic keratitis in a pony

“…In the case described here, it is likely that the organism was introduced onto the corneal surface secondary to a traumatic incident. Anaerobic infections, especially of the upper and lower respiratory tract, are frequently characterised by a malodorous smell (Hodgson et al 2008). The odour associated with the ocular discharge in this case was probably due to the anaerobic infection, although this phenomenon has not been previously described in anaerobic ocular infections.…”

“…Anaerobic infection of the cornea appears to be uncommon in horses, although the condition may be underreported, as specific anaerobic culture methods are not routinely employed for corneal specimens. Successful culturing of anaerobes requires careful sample handling to ensure anaerobic conditions are maintained if a delay between collection and processing is anticipated (Hodgson et al 2008). Although successful resolution may occur with aggressive medical management, rapid progression of the ulcer may suggest a poor prognosis.…”

Antimicrobial stewardship in equine practice

“…The importance of initial antimicrobial selection has recently been demonstrated in foals, with increased survival in animals where all isolates were susceptible to initial (empirical) antimicrobial selection, and the importance of accurate laboratory identification and sensitivity testing of bacterial isolates has already been discussed. This process begins with the collection of suitable samples and appropriate transportation to the diagnostic laboratory . Blood and body fluid samples should ideally be collected into blood culture bottles for transportation, with due care to prevent sample contamination and to ensure that the site cultured is free of commensal organisms (e.g.…”

“…This process begins with the collection of suitable samples and appropriate transportation to the diagnostic laboratory. 23 Blood and body fluid samples should ideally be collected into blood culture bottles for transportation, with due care to prevent sample contamination and to ensure that the site cultured is free of commensal organisms (e.g. submission of aseptically collected synovial fluid is appropriate where a wound may communicate with a joint, submission of a swab of wound exudate is not appropriate).…”

Diagnosis of bacterial infections. Part 2: Bacterial cultivation, susceptibility testing and interpretation

“…In a previous paper (Hodgson et al 2008) the principles of sample collection and transportation were described, the application of which are imperative for meaningful interpretation of culture and antimicrobial susceptibility results. In this paper we outline appropriate techniques for bacterial isolation and identification with specific focus on interpretation of culture and susceptibility testing.…”