Micro News

February 2008

1. Are your disposable gloves contaminated?

A Chicago study investigates bacterial contamination of unused gloves inside open glove boxes from patient rooms.¹ 75% of the gloves were contaminated with bacteria (mainly hand commensals such as coagulase-negative staphylococci) but a few pathogens were detected including a patient strain of carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa. Unused gloves in patient rooms may act as a reservoir for nosocomial pathogens.

2. Are you watching what you eat?

A new strain of community-associated MRSA is spreading in Holland linked to pig farms called Pig-Associated (PA-MRSA) (based on the epidemiology) or Non-Typeable (NT-MRSA) (based on PFGE typing). A study from some researchers in Holland found that 34 (43%) of 79 raw meat samples harboured Staphylococcus aureus, including two MRSAs, one of which was NT-MRSA.² The concentration of MRSA contamination was low and detected by enrichment culture only; however, the discovery of any amount of MRSA in raw foods at the point of sale is concerning.

3. Opening Pandora’s box of S. aureus carriage in healthcare workers

A study from Johns Hopkins in Baltimore investigated S. aureus nasal colonisation in healthcare workers.³ The findings suggest that the carriage of MRSA is low (2% of the 200 HCWs surveyed) and none of the MRSA strains were community-associated types, which have been associated with infections in HCW in the same institution.⁴ The personal risk associated with caring for patients with healthcare-associated MRSA appears to be low.

4. C. difficile: it’s airborne!

Several studies in the past have failed to isolate C. difficile from ward air. A recent study from Leeds has identified C. difficile in a high proportion of air samples collected on a care-of-the-elderly ward in a bay used to nurse patients with C. difficile-associated disease.⁵ Surprisingly, concomitant surface sampling using small contact plates did not yield any C. difficile, suggesting that the airborne C. difficile spores did not settle on surfaces. In the light of these findings, further evaluation of the role of airborne dissemination of C. difficile spores is warranted.

5. MRSA environmental contamination on a London neonatal unit

During a small outbreak of ciprofloxacin-susceptible EMRSA-15 on a London neonatal unit, MRSA was cultured from 8 (16.7%) of 48 surfaces sampled, including the outbreak strain from 4 surfaces and distinct MRSA from 4 surfaces.⁶ The outbreak strain was cultured from surfaces after terminal cleaning and from communal surfaces; improved environmental decontamination was part of the outbreak response. Another feature of the outbreak was the fact that the use of ciprofloxacin-containing screening media did not support the growth of the outbreak strain. The use of ciprofloxacin-containing media should be avoided, particularly in paediatrics where CA-MRSA, which is typically susceptible to ciprofloxacin, may be increasing in frequency.

6. Norovirus outbreak traced to a contaminated keyboard

An outbreak of Norovirus occurred in a US elementary school affecting 103 (39%) of 266 staff members and children at the school.⁶ One classroom in particular was associated with transmission, and this was the only classroom in which staff and students shared computers. Norovirus DNA matching the outbreak strain was detected on one such shared computer keyboard in this classroom. Fomites that are shared but not commonly cleaned, such as computer keyboards, should be decontaminated during outbreaks of Norovirus.
 
7. And finally…a sneaky drink from the garden hose…

A man seeking a refreshing drink from his garden hose on a hot summer’s day got more than he bargained for when he contracted Legionella!⁸⁷Could garden hose usage be a previously unrecognised risk factor for Legionella?

References

Diaz MH, Silkaitis C, Malczynski M, Noskin GA, Warren JR, Zembower T. Contamination of examination gloves in patient rooms and implications for transmission of antimicrobial-resistant microorganisms. Infect Control Hosp Epidemiol 2008;29:63-65.

van Loo I, Diederen BM, Savelkoul PH, Woudenberg JH, Roosendaal R, van BA, Lemmens-den TN, Verhulst C, van Keulen PH, Kluytmans JA. Methicillin-resistant Staphylococcus aureus in meat products, the Netherlands. Emerg Infect Dis 2007;13:1753-1755.

Johnston CP, Stokes AK, Ross T, Cai M, Carroll KC, Cosgrove SE, Perl TM. Staphylococcus aureus colonization among healthcare workers at a tertiary care hospital. Infect Control Hosp Epidemiol 2007;28:1404-1407.

Johnston CP, Cooper L, Ruby W, Carroll KC, Cosgrove SE, Perl TM. Epidemiology of community-acquired methicillin-resistant Staphylococcus aureus skin infections among healthcare workers in an outpatient clinic. Infect Control Hosp Epidemiol 2006;27:1133-1136. 

Roberts K, Smith CF, Snelling AM, Kerr KG, Banfield KR, Sleigh PA, Beggs CB. Aerial dissemination of Clostridium difficile spores. BMC Infect Dis 2008;8:7.

Otter JA, Klein JL, Watts TL, Kearns AM, French GL. Identification ancontrol of an outbreak of ciprofloxacin-susceptible EMRSA-15 on a neonatal unit. Journal of Hospital Infection 2007;67:232-239.

CDC. Norovirus Outbreak in an Elementary School --- District of Columbia, February 2007. MMWR Weekly 56(51);1340-1343.

Piso RJ, Caruso A, Nebiker M. Hose as a source of Legionella pneumonia. A new risk factor for gardeners? J Hosp Infect 2007;67:396-397.