Prevalence, characterization, and antibiotic susceptibility of Cronobacter spp. in a milk powder processing...

Area of Science:

• Food Microbiology
• Bacteriology
• Public Health Microbiology

Background:

• Cronobacter spp. are opportunistic foodborne pathogens, primarily affecting neonates and infants via contaminated powdered infant formula.
• No prior reports exist on Cronobacter spp. prevalence in Serbian milk powder production environments.

Purpose of the Study:

• To determine the prevalence, molecular characteristics, antimicrobial susceptibility, and biofilm-forming capacity of Cronobacter spp. in a Serbian milk powder plant.

Main Methods:

• Isolation and identification of Cronobacter spp. from 100 milk powder production samples.
• Multi-locus sequence typing (MLST) for molecular characterization.
• Antimicrobial susceptibility testing and biofilm formation assays.

Main Results:

• A 15% contamination rate with Cronobacter sakazakii was observed, with 15 strains isolated.
• Five sequence types (STs) were identified, including dominant ST4 (50%), ST1, and ST83. A novel ST759 was registered.
• Most ST4 isolates exhibited moderate-to-strong biofilm-forming ability. Strains were susceptible to specific antibiotics like meropenem and cefotaxime.

Conclusions:

• The presence of clinically relevant Cronobacter sakazakii isolates (ST4, ST1, ST83, ST8) in the production plant poses a potential public health risk.
• The identification of a novel sequence type (ST759) indicates ongoing genetic evolution within Cronobacter sakazakii populations.
• Effective control measures are crucial in milk powder production environments to mitigate the risk of Cronobacter contamination.