Healthcare Associated Infections and Opportunistic Pathogens

Bacteria and fungi are ubiquitous in all environmental settings, including hospitals, critical care areas, surgical suites, ICUs and pharmacies. Nursing homes and acute care facilities that care for those with compromised immune systems are also of concern. Although environmental microbial sampling of the areas mentioned above is not recommended on a routine basis, there are a number of circumstances in which sampling may be judged necessary: (i) when Healthcare Associated Infections (HAI’s) are due to common airborne bacteria and fungi; (ii) during outdoor or indoor construction in close proximity to susceptible patients; (iii) commissioning of new space with specialized controlled environments, and (iv) when procedures necessary for the cleanest air quality are being established and maintained.

Healthcare Associated Infections, (HAI’s) are infections caused by bacteria or fungi contracted during a stay in a hospital, nursing home or rehabilitation facility. In some cases the etiologic agent causing the infection, is a bacterium that may be shed off skin cells or the respiratory tract of employees or visitors, such as Micrococcus sppCoagulase-negative Staphylococcus sppCorynebacterium spp, and Staphylococcus aureus, especially Methicillin-Resistant Staphylococcus aureus (MRSA). In this instance, healthcare acquired MRSA is noted as HA-MRSA as opposed to community acquired methicillin-resistant Staphylococcus aureus – CA-MRSA, which are infections acquired outside a hospital or healthcare facility. Environmental bacteria and fungi that are not related to human activity also contribute to the bacteria and fungi population. These organisms may be gram-negative rods such as Pseudomonas sppAcinetobacter spp; Carbapenem-resistant Enterobacteriaceae, (CRE); Bacillus spp; or fungi, such as Aspergillus sppPenicillium sppCladosporium spp., yeasts brought in on plants, flowers or the soles of shoes. Bacteria and fungi entrained in the heating, ventilation and air conditioning system from outdoor intakes are another source. Inherent reservoirs inside critical areas may include bedding, cleaning materials, trash, water systems (water lines, hydrotherapy equipment and inhalation equipment) and engineering controls such as filters, cooling coils and ductwork.

Click on the links on the left navigation bar to learn more about hospital related testing.


Additional Resource Links:

The CDC | Methicillin-resistant Staphylococcus aureus (MRSA)


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