Safety issues of raw milk: evaluation of bacteriological and physicochemical characteristics of human milk from a bank in a teaching hospital, focusing on Staphylococcus species

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Tatiana Salerno, Amanda Keller Siqueira, José Paes de Almeida Nogueira Pinto, Maria de Lourdes Ribeiro de Souza da Cunha, Patrícia Kelly Silvestre, Larissa Anuska Zeni Condas, Gustavo Henrique Batista Lara, Juliano Gonçalves Pereira, Aristeu Vieira da Silva, Fernando José Paganini Listoni, Lorrayne de Souza Araújo Martins, Rodrigo Garcia Motta, Márcio Garcia Ribeiro
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 2021
• Subjects: Neonatal milk; Human milk banks; Breastfeeding; Multidrug-resistant bacteria; Staphylococcal toxins; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1590/s1678-9946202163054; https://doaj.org/article/ee202136ac364850be5d0cfefa593187

ABSTRACT Many infants are nurtured with milk supplied by human banks, whose bacteriological and physical-chemical profiles are a major issue. We investigated the bacteriological and physical-chemical characteristics, as well as genotypic and phenotypic and profiles of Staphylococcus species isolated from 240 samples of breast milk from a bank in a teaching hospital. Dornic acidity of milk revealed that 95.4% (229/240) had acceptable limits (< 8.0 oD). Caloric intake showed a wide variation in cream content (4%), fat (4%) and energy values (559.81 Kcal/L). Staphylococcus (105/186 or 56.5%) and Enterobacter (25/186 or 13.4%) were the most prevalent genera, although other microorganisms were identified, including Klebsiella pneumoniae and Pseudomonas aeruginosa. Amoxicillin/clavulanic acid (125/157 or 79.6%), vancomycin (115/157 or 73.2%), and cephalexin (112/157 or 71.3%) were the most effective antimicrobials. High resistance rates of isolates were found to penicillin G (141/157 or 89.8%), ampicillin (135/157 or 86%), and oxacillin (118/157 or 75.2%). Multidrug resistance to ≥ 3 antimicrobials occurred in 66.2% (123/186) of the isolates. Residues of microbial multiplication inhibitory substances were found in 85% (204/240) of samples. Among the coagulase-positive-CPS and negative-CoNS staphylococci, the mecA gene was detected in 53.3% (8/15) and 75% (30/40), respectively. Genes sea, seb and sec were detected in 20% (3/15) of CPS, while tsst-1 was detected in 13.34% (2/15). In addition, 13.3% (2/15) of S. aureus were toxin-producers. Genes sea, seb and sec were detected in 90% (36/40), 5% (2/40) and 15% (6/40) CoNS, respectively. Enterotoxin production was identified in 5% (2/40) of CoNS. The identification of multidrug-resistant bacteria, staphylococci species toxin-producers harboring methicillin-resistance genes, and residues of microbial multiplication inhibitory substances reinforce the need for a continuous vigilance of milk quality offered to infant consumption by human banks.