WHO Guidelines on Hand Hygiene in Health Care - Safe Care ...

<strong>WHO</strong> GUIDELINES ON HAND HYGIENE IN HEALTH CARE
7.
Transmission of pathogens by hands
Transmission of health care-associated pathogens from one patient to another via HCWs’ hands requires
five sequential steps (Figures I.7.1–6): (i) organisms are present on the patient’s skin, or have been shed onto
inanimate objects immediately surrounding the patient; (ii) organisms must be transferred to the hands of HCWs;
(iii) organisms must be capable of surviving for at least several minutes on HCWs’ hands; (iv) handwashing
or hand antisepsis by the HCW must be inadequate or entirely omitted, or the agent used for hand hygiene
inappropriate; and (v) the contaminated hand or hands of the caregiver must come into direct contact with
another patient or with an inanimate object that will come into direct contact with the patient. Evidence
supporting each of these elements is given below.
7.1 Organisms present on patient skin or in the
inanimate environment
Health care-associated pathogens can be recovered not only
from infected or draining wounds, but also from frequently
colonized areas of normal, intact patient skin. 82-96 The perineal or
inguinal areas tend to be most heavily colonized, but the axillae,
trunk, and upper extremities (including the hands) are also
frequently colonized. 85,86,88,89,91,93,97 The number of organisms
such as S. aureus, Proteus mirabilis, Klebsiella spp. and
Acinetobacter spp. present on intact areas of the skin of some
patients can vary from 100 to 10 6 CFU/cm 2 . 86,88,92,98 Diabetics,
patients undergoing dialysis for chronic renal failure, and those
with chronic dermatitis are particularly likely to have skin areas
colonized with S. aureus. 99-106 . Because nearly 10 6 skin squames
containing viable microorganisms are shed daily from normal
skin, 107 it is not surprising that patient gowns, bed linen, bedside
furniture and other objects in the immediate environment of
the patient become contaminated with patient flora. 93-96,108-114
Such contamination is most likely to be due to staphylococci,
enterococci or Clostridium difficile which are more resistant to
desiccation. Contamination of the inanimate environment has
also been detected on ward handwash station surfaces and
many of the organisms isolated were staphylococci. 115 Tap/
faucet handles were more likely to be contaminated and to be in
excess of benchmark values than other parts of the station. This
study emphasizes the potential importance of environmental
contamination on microbial cross contamination and pathogen
spread. 115 Certain Gram-negative rods, such as Acinetobacter
baumannii, can also play an important role in environmental
contamination due to their long-time survival capacities. 116-119
7.2 Organism transfer to health-care workers’ hands
Relatively few data are available regarding the types of
patient-care activities that result in transmission of patient
flora to HCWs’ hands. 72,89,110,111,120-123 In the past, attempts have
been made to stratify patient-care activities into those most
likely to cause hand contamination, 124 but such stratification
schemes were never validated by quantifying the level of
bacterial contamination that occurred. Casewell & Phillips 121
demonstrated that nurses could contaminate their hands with
100–1000 CFU of Klebsiella spp. during “clean” activities such
as lifting patients; taking the patient’s pulse, blood pressure
or oral temperature; or touching the patient’s hand, shoulder
or groin. Similarly, Ehrenkranz and colleagues 88 cultured the
hands of nurses who touched the groin of patients heavily
colonized with P. mirabilis and found 10–600 CFU/ml in glove
juice samples. Pittet and colleagues 72 studied contamination of
HCWs’ hands before and after direct patient contact, wound
care, intravascular catheter care, respiratory tract care or
handling patient secretions. Using agar fingertip impression
plates, they found that the number of bacteria recovered from
fingertips ranged from 0 to 300 CFU. Direct patient contact
and respiratory tract care were most likely to contaminate
the fingers of caregivers. Gram-negative bacilli accounted for
15% of isolates and S. aureus for 11%. Importantly, duration of
patient-care activity was strongly associated with the intensity
of bacterial contamination of HCWs’ hands in this study. A
similar study of hand contamination during routine neonatal care
defined skin contact, nappy/diaper change, and respiratory care
as independent predictors of hand contamination. 73 In the latter
study, the use of gloves did not fully protect HCWs’ hands from
bacterial contamination, and glove contamination was almost as
high as ungloved hand contamination following patient contact.
In contrast, the use of gloves during procedures such as nappy/
diaper change and respiratory care almost halved the average
increase of bacteria CFU/min on HCWs’ hands. 73
Several other studies have documented that HCWs can
contaminate their hands or gloves with Gram-negative bacilli,
S. aureus, enterococci or C. difficile by performing “clean
procedures” or touching intact areas of skin of hospitalized
patients. 89,95,110,111,125,126 A recent study that involved culturing
HCWs’ hands after various activities showed that hands were
contaminated following patient contact and after contact with
body fluids or waste. 127 McBryde and colleagues 128 estimated
the frequency of HCWs’ glove contamination with methicillinresistant
S. aureus (MRSA) after contact with a colonized
patient. HCWs were intercepted after a patient-care episode
and cultures were taken from their gloved hands before
handwashing had occurred; 17% (confidence interval (CI)
95% 9–25%) of contacts with patients, a patient’s clothing or a
patient’s bed resulted in transmission of MRSA from a patient
to the HCWs’ gloves. In another study involving HCWs caring
for patients with vancomycin-resistant enterococci (VRE),
70% of HCWs contaminated their hands or gloves by touching
the patient and the patient’s environment. 114 Furthermore,
HCWs caring for infants with respiratory syncytial virus (RSV)
infections have acquired infection by performing activities such
as feeding infants, nappy/diaper change, and playing with
the infant. 122 Caregivers who had contact only with surfaces
contaminated with the infants’ secretions also acquired RSV.
In the above studies, HCWs contaminated their hands with
RSV and inoculated their oral or conjunctival mucosa. Other
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