Technological advances have expanded the role of the clinical microbiology laboratory in supporting management and control of health-care-associated infections (HAI). Diagnostic capabilities have been complemented by new methods for characterisation of microbial antigens and nucleic acids. Genomic "fingerprinting" enables the study of transmission of nosocomial pathogens. Monitoring of their antimicrobial resistance patterns has gained critical importance. However, cost-effective application of microbiological testing for improved treatment and prevention of HAI requires further study.