An evaluation of alternative buffers for the transport and detection of Moraxella bovis and M. bovoculi on cotton wool swabs

Abstract

Bovine keratoconjunctivitis is a globally important inflammatory condition affecting the eyes of cattle. The reliable detection of Moraxella bovis and M. bovoculi on conjunctival specimens is crucial for observational studies aiming to unravel the complex epidemiology of this disease. The stability of Moraxella DNA was evaluated in three experiments using cotton wool swabs spiked with varying concentrations of sample suspensions and submitted either with or without DNA stabilizers. Swabs were subjected to different storage temperatures (4 °C or 25 °C), and DNA was extracted at 0, 24, 48, and 72 h using an automated system, followed by qPCR analysis. DNA from both species remained detectable on damp cotton-wool swabs under all conditions, indicating resilience to transport delays and cold-chain interruptions. Although MagNA Pure Bacteria Lysis Buffer and MagNA Pure DNA Tissue Lysis Buffer provided acceptable stabilization, specimen submission without stabilizers was analytically more sensitive, detecting Moraxella DNA at higher dilutions and yielding higher inferred DNA concentrations (lower Cq values). These results indicate that Moraxella specimens can be packaged for transport without stabilizing buffers.

HIGHLIGHTS • Moraxella DNA is stable on moist cotton wool swabs for up to three days. • qPCR detection of Moraxella DNA on swabs is more sensitive without DNA stabilizers. • RNA-optimized stabilizers poorly preserve Moraxella DNA on swabs.