Transmission of infectious agents in healthcare settings: a systematic review of healthcare-associated infections.

OBJECTIVES

This study aimed to systematically analyse original research publications to provide a comprehensive assessment of the transmission chain of healthcare-associated infections (HAIs). The review focused on identifying transmission routes, sources of pathogen detection, and the predominant microorganisms detected in healthcare environments.

METHODS

A systematic review was performed following PRISMA methodology. Relevant studies were searched in PubMed and Scopus databases using predefined keywords.

RESULTS

Forty-four original studies published in English between January 2015 and July 2025 were included. Indirect transmission was reported in 37 (84.1%) studies, while 27 (61.4%) studies identified it as the sole transmission route. Fomites were reported as the sole source of pathogen detection in 30 (68.2%) studies. Among studies investigating fomites or environmental contamination, stethoscopes were the leading contaminated item (n = 5, 13.5%). Among detected microorganisms, Gram-negative bacilli (n = 94, 51.1%) and Gram-positive cocci (n = 76, 41.3%) prevailed. The dominant bacterial genus was Staphylococcus spp. (n = 55, 29.9%), whereas Staphylococcus aureus represented the leading species (n = 25, 13.6%), followed by Klebsiella pneumoniae (n = 12, 6.5%) and Escherichia coli (n = 11, 6.0%). Multidrug-resistant strains, including methicillin-resistant Staphylococcus aureus (n = 11, 6.0%) were also observed.

CONCLUSION

Indirect transmission through contaminated fomites represented the predominant transmission pathway, including medical devices such as stethoscopes. Staphylococcus aureus was among the most frequently detected microorganisms, while multidrug-resistant organisms were also reported. These findings emphasize the importance of infection prevention and control measures in healthcare settings.