Infection control is the discipline concerned with preventing nosocomial or healthcare-associated infections.   It is about identifying and controlling the factors involved with the spread of these infections, whether from patient-to-patient, from patients to staff, from staff to patients, or among-staff.  These factors include prevention (via hand hygiene/hand washing,  cleaning / disinfection / sterilization, vaccination, surveillance);   monitoring/investigation of demonstrated or suspected causes for spread of infection within a particular health-care setting;   and the surveillance,  investigation,  and management  of outbreaks. It is on this basis that the more common title being adopted within health care is “infection prevention and control.”[i]

In the United States, the Centers for Disease Control and Prevention estimated roughly 1.7 million hospital-associated infections, from all types of microorganisms combined, cause or contribute to 99,000 deaths each year.  The most frequent type of infection hospital-wide is urinary tract infection (36%), followed by surgical site infection (20%), and bloodstream infection and pneumonia (both 11%)[ii]

Hospital-acquired infections are an important category of hospital-acquired conditions. HAI is sometimes expanded as healthcare-associated infection to emphasize that infections can be correlated with health care in various settings (besides hospitals, such as nursing homes), which is also true of hospital-acquired conditions generally.

The CDC, through its guidelines development, nosocomial infection surveillance methodology, outbreak investigations, and laboratory studies, has provided much of the scientific and epidemiologic basis for infection control in the United States. It also organized some of the early training for infection control programs and hospital epidemiologists.                

Surveillance of Nosocomial Infections

Surveillance is defined as “the ongoing, systematic collection, analysis, and interpretation of health data essential to the planning, implementation, and evaluation of public health practice, closely integrated with the timely dissemination of these data to those who need to know”   Surveillance, which is an essential element of an infection control program, provides the data to identify infected patients and determine the site of infection and the factors that contributed to the infection. When infection problems are recognized, the hospital is able to institute appropriate intervention measures and evaluate their efficacy. Surveillance data are also used to assess the quality of care in the hospital.

Requirements of a Successful Infection Control Committee Surveillance Program include:

  • Clear goals for doing surveillance. These goals must be reviewed and updated frequently to meet new infection risks in changing patient populations, the introduction of new high-risk medical interventions, and changing pathogens and their resistance to antibiotics.
  • Trained Personnel with knowledge of clinical patient care, epidemiology and microbiology
  • Accepted definitions and criteria for nosocomial infections, risk factors, and other outcomes
  • Readily available sources of data for identifying infections
  • Systems in place for data analysis, dissemination, and confidentiality
  • Identifying infected patients
  • Use of surveillance data for continuous quality improvement.

 As the source of microbiologic culture information, the laboratory must provide easy access to high-quality and timely data and give guidance and support on how to use its resources for epidemiologic purposes.

The services that the infection control program can offer to the laboratory include functioning as a liaison to the clinical services to improve the quality of specimens sent to the laboratory and promoting appropriate use of cultures and other laboratory tests. It can also assist the laboratory with its system for monitoring antimicrobial agent susceptibilities by identifying the pathogens that are of nosocomial origin.

The microbiology Laboratory contributes to the work of the Infection Control Program by   fulfilling its technical responsibilities by performing quality microbiology investigations through:[iv] 

  • Proper Specimen Collection
  • Accurate Identification and Susceptibility Testing
  • Laboratory Information Systems for comprehensive information /ordering
  • Rapid Diagnostic Testing
  • Rapid reporting of Laboratory Data
  • Outbreak Recognition and Investigations – Molecular Typing
  • Maintaining Organism Storage
  • Maintaining Cultures of Specimens from Hospital Personnel and the Environment


Infection control is concerned with preventing nosocomial or healthcare-associated infections. Surveillance, which is an essential element of an infection control program, provides the data to identify infected patients and determine the site of infection and the factors that contributed to the infection.

The microbiology laboratory should be involved in all aspects of the infection control program. Particularly important are its roles in the hospital infection surveillance, as well as assisting the infection control program to effectively and efficiently utilize laboratory services for epidemiologic   purposes;  equally important is  the quality of the technical work performed, and the expertise  provided.

[i] Infection Control: Wikipedia-the free encyclopedia. June 2015.
[ii] Hospital-Acquired Infection: Wikipedia-the free encyclopedia. 2015.
[iii]  Emori, T.G., and Gaynes, R.P.  1993.  An Overview of Nosocomial Infections, Including the Role of the Microbiology Laboratory   Clinical Microbiology Reviews.  V.6, No. 4, P.428-442.
[iv] Johnson, J.K. Role of the Microbiologist in Infection Control and Hospital Epidemiology.  July 7, 2014