Antimicrobial Resistance of <i>Escherichia coli</i> in Dairy Calves: A 15-Year Retrospective Analysis and Comparison of Treated and Untreated Animals
Nicoletta Formenti,
Chiara Martinelli,
Nicoletta Vitale,
Stefano Giovannini,
Cristian Salogni,
Matteo Tonni,
Federico Scali,
Laura Birbes,
Mario D’Incau,
Flavia Guarneri,
Paolo Pasquali,
Giovanni Loris Alborali
Affiliations
Nicoletta Formenti
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Chiara Martinelli
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Nicoletta Vitale
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Stefano Giovannini
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Cristian Salogni
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Matteo Tonni
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Federico Scali
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Laura Birbes
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Mario D’Incau
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Flavia Guarneri
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
Paolo Pasquali
Dipartimento di Sicurezza Alimentare, Nutrizione e Sanità Pubblica Veterinaria, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy
Giovanni Loris Alborali
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Via Bianchi 7/9, 25124 Brescia, Italy
The health problem of antimicrobial resistance (AMR) involves several species. AMR surveillance is essential to identify its development and design control strategies; however, available data are still limited in some contexts. The AMR profiles of 2612 E. coli strains isolated over a period of 15 years (2002–2016) from calf enteric cases were analyzed to determine the presence of resistance and their temporal dynamics. Furthermore, the AMR profiles and the presence of the major virulence genes of 505 E. coli strains isolated from 1-week- and 2-week-old calves, 406 treated with antimicrobials and 99 untreated, were analyzed and compared to investigate the potential effects of treatment on AMR and strain pathogenicity. Resistance to tetracycline (90.70%) was the most common, followed by resistance to sulfamethoxazole/trimethoprim (77.70%) and flumequine (72.10%). The significantly higher percentage of AMR and virulence gene expression recorded in treated calves, combined with the statistically higher resistance to sulfamethoxazole/trimethoprim in E. coli with K99, corroborates the notion of resistance being induced by the frequent use of antimicrobials, leading to treatments potentially becoming ineffective. The significantly higher resistance to amoxicillin/clavulanic acid, enrofloxacin, and florfenicol in isolates from 1-week-old calves suggests the role of the environment as a source of contamination that should be investigated further.
