Occurrence of extended-spectrum β-lactamase-producing Enterobacteriaceae in raw milk from cows with subclinical mastitis in northeast Brazil

• Published in: Brazilian journal of microbiology Vol. 54; no. 2; pp. 1303 - 1307
• Main Authors: Sierra, Tania Alexandra Ortega, Acosta, Atzel Candido, de Melo, Renata Pimentel Bandeira, de Oliveira, Pollyanne Raysa Fernandes, de Moraes Peixoto, Rodolfo, Cavalcanti, Erika Fernanda Torres Samico Fernandes, Junior, José Wilton Pinheiro, Mota, Rinaldo Aparecido
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-06-2023; Springer Nature B.V
• Subjects: Amoxicillin; Animals; Anti-Bacterial Agents - pharmacology; Antibiotics; Bacteria; beta-Lactamases - genetics; Biomedical and Life Sciences; Brazil - epidemiology; Cattle; Cephalosporins; Citrobacter; Clavulanic acid; Cow's milk; E coli; Enterobacteriaceae; Enterobacteriaceae - genetics; Escherichia coli - genetics; Female; Food Microbiology; Gram-negative bacteria; Humans; Klebsiella; Life Sciences; Mastitis; Mastitis, Bovine - microbiology; Medical Microbiology; Microbial Ecology; Microbial Genetics and Genomics; Microbial Sensitivity Tests; Microbiology; Milk; Milk - microbiology; Mycology; Veterinary Microbiology - Short Communication; β Lactamase; β-Lactam antibiotics; Brazil; Subclinical mastitis; Food safety; Bacterial resistance; Antimicrobials
• ISSN: 1517-8382; 1678-4405
• DOI: 10.1007/s42770-023-00955-x

Extended-spectrum β-lactamase (ESBL)-producing Gram negative bacteria are becoming increasingly important in veterinary and human medicine because they can hydrolyze the third generation β-lactams, penicillins, and monobactams. The aim of this study was to identify ESBL-producing
Enterobacteriaceae
in raw cow milk samples from northeast Brazil. Twenty-six bacterial isolates belonging to the
Enterobacteriaceae
family were obtained from milk samples from 257 cows with subclinical mastitis. Using microbiological tests, 53.85% (14/26) were identified as
Escherichia coli
, 15.38% (4/26) as
Proteus mirabilis
, 26.92% (7/26) as
Klebsiella
spp., and 3.85% (1/26) as
Citrobacter
spp. Of all the isolates, 61.54% (16/26) were positive in the ESBL screening test, of which 12.5% (2/16) were positive in the double-disc synergy test using three types of cephalosporins and amoxicillin/clavulanic acid. The two isolates were identified as
Klebsiella
spp. Among all the isolates, 53.85% (14/26) were positive for one or both ESBL-encoding genes,
blaSHV
and
blaTEM
; among these, 71.43% (10/14) were identified as
E. coli
. This study demonstrates that ESBL-producing bacteria can be found in raw cow milk from northeast Brazil. Cows with subclinical mastitis should be recognized as reservoirs of these strains, which can propagate to humans.