关键词: 婴幼儿配方乳粉, 生产车间, 微生物, 16S rDNA 基因测序技术, 群落分析, 耐药性

Abstract: Objective: To investigate the microbial species and community structure of infant formula milk powder workshops in Fujian Province in 2024, in order to reveal the microbial diversity present in the workshops as well as the changes in the distribution of microorganisms among different functions and drug resistance.Methods: A stratified random sampling strategy was employed to collect surface microbiota, airborne planktonic bacteria, and sedimentary microbes from selected manufacturing facilities using aseptic swabbing, six-stage Andersen air sampling, and plate exposure methods respectively. Environmental isolates underwent 16S rDNA gene sequencing for phylogenetic tree construction via MEGA software, complemented by multi-sequence alignment and evolutionary analysis. To ensure taxonomic accuracy, VITEK? 2 Compact automated microbiology system was utilized for physiological-biochemical characterization, cross-validated against phenotypic traits referenced in the latest Bergey's Manual of Determinative Bacteriology. A dual verification framework integrating molecular and traditional phenotypic identification was thereby established. Antimicrobial susceptibility testing was performed using standardized protocols, with results visualized through heatmap analysis.Results: A total of 355 microbial isolates were recovered, representing 19 genera. Gram-positive bacteria dominated (61.1%), with Staphylococcus (33.8%), Bacillus (26.5%), and Pseudomonas (12.6%) as the primary taxa. Phylogenetic analysis of Staphylococcus spp. revealed significant clonal diversity, while spatial distribution patterns indicated human-material flow as the principal contamination vector. Antimicrobial susceptibility testing demonstrated 100% susceptibility of coagulase-negative staphylococci (CoNS) to teicoplanin, vancomycin, and linezolid. Variable resistance was observed against β-lactams (penicillin G: 20-90% resistance), macrolides (erythromycin: 35-75% resistance), and some of the collected environmental flora were already characterized by multi-drug resistance.Conclusion: Staphylococcal species represent the dominant microbial population in infant formula production environments, with human operators identified as the primary contamination source. The observed antimicrobial resistance profiles underscore the need for enhanced personnel hygiene protocols, air purification systems, and real-time microbial monitoring to mitigate product contamination risks.

Key words: Infant formula milk powder, production workshop, microorganisms, 16S rDNA gene sequencing technology, community analysis, drug resistance