Literature Update - February 2006
Compiled by Dr Deb Friedman, VICNISS ID Physician
MRSA - Time to Put Out the Fire!
The recent edition of infection Control Hospital Epidemiology devotes nearly the entire content to Methicillin-Resistant
Staphylococcus aureus.
Kidd et al (Infect Control Hosp Epidemiol 2006;27:201-203), from Brisbane, examined the relatedness
of MRSA strains from patients with cystic fibrosis (CF). The continuing colonization with MRSA of patients with cystic fibrosis
(CF) is an increasing dilemma for CF units, because infected or colonised patients require segregation, and because infection
with MRSA remains a relative contraindication for lung transplantation. In this study, they demonstrated by PFGE that there
was a diversity of MRSA strains in patients with CF. These results suggest that MRSA acquisition likely occurs in association
with attendance at their hospital, and although the point of acquisition is unclear, patient-to-patient strain transmission does
not appear to be exceedingly common.
Researchers from the U.K (Infect Control Hosp Epidemiol 2006;27:127-132) examined the hospital
environment for the presence of MRSA and studied its relationship to patients' acquisition of MRSA.
They found that the ICU environment was heavily contaminated with MRSA, and in 35% of occasions the strains isolated from the
patients and the strains isolated from their immediate environment were indistinguishable. The implications of these findings
are that more-effective cleaning of the hospital environment to eliminate MRSA is a necessity.
Salgado and Farr (Infect Control Hosp Epidemiol 2006;27:116-121) sought to determine what
proportion of patients who are colonized with MRSA at admission are identified by clinical specimens during hospitalisation.
They found that clinical cultures failed to identify 85% of MRSA-colonised patients! A failure to perform surveillance cultures
to identify patients colonised with MRSA and to use contact precautions may be an important reason for the increasing rate of
nosocomial MRSA infection in hospitals. We know that this must hold true for both the USA and Australia.
So, if your hospital is screening for MRSA colonisation, then the results from French researchers will be of interest
(Infect Control Hosp Epidemiol 2006;27:181-184). They compared the sensitivity of screening with
nasal culture alone with that of a multiple-site (groin, axilla and nares) screening method for the identification of carriers
of MRSA on hospital admission. They found that nasal cultures if used alone, would fail to identify one-quarter of colonised
patients. An effective screening program to detect MRSA colonisation should ideally include swabs of more than 1 bodily site-
no doubt every extra specimen increases the labour and costs of a screening program, and will prove problematic for most hospitals.
The failure to identify MRSA reservoirs is the reason why most hospitals cannot halt the spread of MRSA, according to Muto's
editorial. She points out that the evidence of efficacy for control of MRSA with active surveillance cultures and barrier
precautions is clear but most healthcare systems have not elected to implement methods to identify and contain MRSA. She
acknowledges that resources in hospitals are limited, and that it seems reasonable to limit the anatomical sites cultured
and to target high-risk populations for types of culture associated with the highest yield until better and more cost-effective
screening methods are available.
Negative Pressure - Does your Hospital have Adequate Facilities?
In the most recent edition of the American Journal of Infection Control, (Am J Infect Control
2005; 33:571-579), an algorithm for management of patients infected with airborne-spread diseases is presented.
This paper describes how to set up temporary negative-pressure areas if a permanent negative-pressure room is not available in
your hospital. The next best option is a negative-pressure enclosure, such as a tent or booth. If that is not possible, and the
patient cannot be transferred to another facility then there are some measures which can be taken to create temporary negative-pressure.
One of these is to bleed air from the room through a portable room air recirculation system, another less high-tech option is to use
floor and/or window fans to exhaust air outside the patient's room.
This paper gives a good review of isolation precautions for airborne-spread diseases, and is a good one to save for
periodical review.
Where do Adults get Vaccinated Against Influenza?
Researchers in the US assessed locations at which adults receive influenza (flu) vaccinations (Am J
Infect Control 2005;33:563-570). Using data from 1998-1999, influenza vaccination coverage was 19% for persons aged
18-49 years, 36% for persons aged 50-64 years, and 67% for persons aged =65 years. Seventy percent of flu shots received by
persons aged =18 years were reportedly administered in doctors' offices and other traditional settings. Vaccination in non-traditional
settings (e.g. workplace, stores, community centres) was more likely for young, healthy, employed, white, college-educated adults
who had not had a recent routine check-up.
The authors conclude that physicians should offer vaccination services at every opportunity. Increasing access to
vaccination services in non-traditional settings should be considered as another strategy in pursuit of national
vaccination coverage objectives. Obviously, this access to vaccination services would all depend on funding!