Table 1.

Examples of clinically relevant nosocomial pathogens

Microorganisms	Mode of transmission	Length of survival	Disease/symptoms
Bacteria
Acinetobacter baumannii	extensive environmental contamination33	33 days on plastic laminate surface;33 3 days to 5 months on dry inanimate surfaces32	pneumonia and bloodstream infection33
Bordetella pertussis	airborne droplet infection (person-to-person transmission)109	3–5 days on dry inanimate surfaces32	mild whooping cough syndrome110
Clostridium difficile	extensive environmental contamination33	5 months on dry inanimate surfaces and hospital floors32,33	diarrhoea and colitis111
Chlamydia pneumoniae	transmission from asymptomatic carriers112	≤30 h on dry inanimate surfaces32	acute respiratory disease, bronchitis, sinusitis, pneumonia, otitis media and chronic obstructive pulmonary disease, asthma, reactive airway disease, Reiter's syndrome and sarcoidosis113
Corynebacterium diphtheriae	mainly by infected droplet spread through contact with an infected person114	7 days to 6 months on dry inanimate surfaces32	diphtheria115
Escherichia coli	ingestion of contaminated food, water or milk; person-to-person transmission21	1.5 h to 16 months on dry inanimate surfaces32	blood and urinary tract infection30
Enterococcus spp., including VRE	nosocomial and person-to-person transmission; also by transmission on food products116	5 days to 4 months on dry inanimate surfaces;32 ≤58 days on counter tops33	blood, skin and respiratory tract infection30
Haemophilus influenzae	person-to-person transmission through contact with discharges or droplets from the nose or throat of an infected person21	12 days on dry inanimate surfaces32	acute and chronic respiratory tract infections, meningitis117
Klebsiella pneumoniae	contact with contaminated surfaces and objects, medical equipment and blood products118	2 h to >30 months on dry inanimate surfaces32	urinary tract infections, pneumonia, septicaemias and soft tissue infections118
Mycobacterium tuberculosis	sputum droplets (exhaled through a cough or sneeze) of a person with active disease21	1 day to 4 months on dry inanimate surfaces32	lung infection30
Pseudomonas aeruginosa	contamination from tap water and different medical devices119	6 h to 16 months on dry inanimate surface; 5 weeks on dry floor;32 7 h on glass slides33	lung and urinary tract infection30
Serratia marcescens	direct hand-to-hand transmission; with contaminated invasive medical devices, work surfaces, intravenous and topical solutions120	3 days—2 months on dry inanimate surfaces; 5 weeks on dry floor32	urinary tract infections and pneumonia121
Staphylococcus aureus, including MRSA	contact with the organism in a purulent lesion or on the hands; burn units extensively contaminated21,33	S. aureus can remain virulent for 10 days on dry surfaces;122 MRSA can survive for 7 days to 9 weeks on dry inanimate surfaces and 2 days on plastic laminate surfaces32,33	blood, skin and respiratory tract infection, septicaemia and death23
Streptococcus pneumoniae	person to person through close contact via respiratory droplets; illness among casual contacts and attendants is infrequent123	1–20 days on dry inanimate surfaces32	blood, lung and ear infections30
Streptococcus pyogenes	respiratory droplets and skin contact with impetigo lesions124	3 days to 6.5 months on dry inanimate surfaces32	rheumatic fever, sepsis, severe soft-tissue invasion and toxic-shock-like syndrome (TSLS)125
Fungi
Candida spp.	via contaminated medical devices;126 contact with secretions or excretions from infected persons21	1–120 days on dry inanimate surfaces32	infections of the gastrointestinal tract, vagina and oral cavity21
Viruses
HBV	percutaneous or permucosal exposure to blood or secretions via abrasions, sharing needles/syringes, sexual contact127	> 1 week on dry inanimate surfaces32	nausea, vomiting, jaundice; chronic infection leads to hepatocellular carcinoma and cirrhosis21
influenza virus	respiratory droplet or direct contact;127 aerosolization after sweeping; survival on fomites33	24–48 h on non-porous surfaces33	influenza21
SARS-associated coronavirus	spread person to person via infected droplets21	24–72 h on fomites and in stool samples;33 72–96 h on dry inanimate surfaces32	respiratory infection and pneumonia21
norovirus	faecal contaminated vehicle (food or water); person-to-person transmission128	8 h to 7 days on dry inanimate surfaces32	abdominal pain, nausea, vomiting, headache and chills128
rotavirus	primarily faecal–oral transmission; faecal–respiratory transmission can also occur21	6–60 weeks on dry inanimate surfaces32	enteritis: diarrhoea, vomiting, dehydration and low-grade fever21