A call for IPC Epistemic Responsibility – Part 2

In the second of two part blogs, Dr Evonne T Curran, a retired infection prevention control (IPC) nurse, continues to draws on historical examples to highlight the need for IPC professionals to question what they think they know – just because you’ve always been taught that something is right doesn’t mean it is. Evidence from the ongoing covid pandemic suggests this isn’t the case in the UK at the moment.

The first part of this blog can be found be clicking here.

What about the second part of the Pittet et al (2006) claim? Is hand hygiene the most important action to prevent the spread of antimicrobial resistant pathogens? Again, the cited authors’ Boyce et al (2002) omit any comparison or evaluation of the ways drug resistant organisms transmit in the healthcare environment. Ergo, there is nothing within the guideline to support the claim. There are however two citations which are worthy of further consideration as both studies took place over the same time-period and in the same hospital. In the first (Pittet et al 2000) initiated a multi-modal hand hygiene programme and in the second Harbarth et al (2000) introduced an MRSA control programme. The interpretation from the multi-modal hand hygiene study [intervention period 1994 – 1997] is that the “campaign” (including bedside hand hygiene placement) resulted in sustained improvement in hand hygiene (as measured twice a year) which coincided with a reduction in nosocomial MRSA.

The second study by Harbarth et al (2000) [intervention period 1993 – 1997] involved the introduction of MRSA control measures, screening, contact isolation, computerised alert system and “hospital-wide promotion of hand hygiene”. It concluded that “infection control measures had a substantial impact on both the reservoir of MRSA and the attack rate of MRSA bacteraemia.” Ergo multiple interventions in both studies (in the same hospital at the same time) “coincided” with MRSA reduction; however, there is no evidence presented which suggests that hand hygiene (which only ever reached 66% compliance) was the most important primary measure to prevent the spread of antimicrobial resistant pathogens. To add to the challenges of interpreting coinciding events, pathogenic organisms can decline for unknown reasons. What is missing from these papers is an acknowledgement that other routes of transmission happen and in the case of MRSA (and many other pathogens) involve airborne dissemination.

Pittet et al (2006) list papers which show increased hand hygiene coinciding with decreased infection. Let’s look at the first from Casewell & Phillips (1997). This is an important paper because it is one of very few which looked at other methods of transmission – including the air – to explain the spread of Klebsiella spp. Hand plates were positive and, albeit in small numbers, Klebsiella spp were found on settle plates around the bed of positive patients and on impression plates (indicating some airborne dissemination) (Casewell & Phillips 1997). Having identified hands were often contaminated, and that an antiseptic hand wash was very effective at removing the pathogen from hands, in “April 1974”, they emphasised the importance of hand hygiene and introduced a change to the hand washing solution from a soap to an antiseptic. The authors state a reduction in Klebsiella spp “seemed to coincide with the introduction of hand washing in the first quarter” (Casewell & Phillips 1997). Of note, ‘April’ is in the second quarter by which time a decline is evident. The authors’ concluded that “the reduction in klebsiella colonisation or infection of newly admitted patients that coincided with increased hand-washing and which was sustained over two-years, provides perhaps the most convincing evidence that hands are a major, but correctable, route of transmission for Klebsiella spp”  (Casewell & Phillips 1997). I am unconvinced. Although it was correct to say the Klebsiella spp declined over 2 years, the intervention (hand washing compliance with an antiseptic) was never measured! Thus, whether it increased, decreased, or remained the same is unknown. Clearly, there is an absence of evidence to conclude it was the hand washing wot did it. The authors clearly favour contact transmission; yet there is no consideration as to how the Klebsiella spp got into the nasopharynx of all 7 ITU patients (Casewell & Phillips 1997). In one of the most important antimicrobial resistant outbreaks in an neurological ICU the pathogen (also Klebsiella spp) was eradicated by the stopping of all antibiotics for a period of 4 months (Price & Sleigh 1970). Hand hygiene was not mentioned in this report. Clearly, there are other claims on primary measures to prevent HCAI if only we look for them.

To summarise:

• The process that identified a physics defying mode of respiratory transmission should have resulted in IPC leadership exercising epistemic responsibility by reviewing all stated modes of transmission
• A lack of epistemic responsibility is perhaps also to blame for a yet unevidenced interpretation of hand hygiene being the primary measure to prevent HCAI.
• It is possible that in desiring to identify and focus on a single most important cause of HCAI (and cross-transmission), researchers overstated the importance of their findings and the findings of others.

Ergo, IPC needs to exercise epistemic responsibility and apply it to all its transmission assertions.

Footnote: hand hygiene is important – it is essential and critical to preventing transmission. Yet there is a lack of evidence for it being the number 1 prevention measure in all settings. I am content to critically review any individual paper which claims hand hygiene primacy in the prevention of HCAI.