Mass spectrometry-based identification reveals the complexity of microorganisms involved in umbilical infections in lambs clinically scored

Espectrometria de massas revela complexidade de micro-organismos isolados em infecções umbilicais em cordeiros com avaliação dos escores de gravidade clínica

We investigated the microbiological etiology of umbilical infections in clinically scored lambs. A total of 128 lambs showing signs of umbilical infection and 41 showing no umbilical signs were sampled. All microorganisms were identified by mass spectrometry (MALDI-TOF MS), and the in vitro antimicrobial susceptibility/resistance patterns of bacteria were assessed. Among the diseased animals and those without umbilical signs, 214 and 116 species of microorganisms (bacteria and yeasts) were identified, respectively. Escherichia coli (11.21%) was the most prevalent microorganism and showed a significant association (p= 0.0039) with moderate (score 2) and severe (score 3) scores for umbilical infection. In lambs without clinical signs of umbilical infection, a predominance of Desemzia incerta was observed. Diseased lambs that exhibited clinical complications showed a high mortality rate (58%). Additionally, a significant association (p< 0.001) was observed between moderate and severe scores and poor prognosis. Bacterial multidrug resistance was observed in 20% (36/182) of isolates. To our knowledge, some bacteria were identified for the first time as primary agents of umbilical infections in lambs, and clinical scoring was applied for the first time in newborn lambs with omphalopathies. Our findings reveal a high complexity of microorganisms in umbilical infections in lambs, identified by mass spectrometry, with a predominance of E. coli in cases of moderate to severe severity scores, and an association between clinical complications and high mortality.

INDEX TERMS:
Infectious omphalopathies; sheep; etiology; multidrug-resistant bacteria; MALDI-TOF MS