Prevention of systemic mycoses by reducing exposure to fungal pathogens in hospitalized and ambulatory neutropenic patients

PURPOSE/OBJECTIVES

To describe sources of fungal contamination that can incite invasive mycoses in hospitalized and ambulatory neutropenic patients and to discuss approaches to reduce exposure to pathogens.

DATA SOURCES

Published articles, books, and brochures.

DATA SYNTHESIS

Modifications of patient environments and lifestyles include hand hygiene for patients and healthcare workers, air filtration in hospitals, and reduction in exposure to plants, soil, standing water, and dusty environments. The effectiveness of dietary restrictions is controversial, although avoidance of pepper is recommended. These restrictions should be implemented prior to, during, and following neutropenia.

CONCLUSIONS

Mycoses can be hospital or community acquired; however, although guidelines for environmental and lifestyle modifications are well documented for the institutional setting, they are more limited for ambulatory patients.

IMPLICATIONS FOR NURSING

Nurses have a key role in the early identification of outbreaks of fungal infections, evaluation of hospital and home environments for sources of pathogens, education of patients on preventive measures, and research on neutropenic diets and improved technology to reduce exposure to fungal pathogens.

Eight-year surveillance of environmental fungal contamination in hospital operating rooms and haematological units

An eight-year fungal environmental surveillance was carried out in 15 operating theatres and two haematological units. Sampling was performed twice a year in each room, using contact plates for plane surfaces and sterile swabs for grids. From 1992 to 1999, individual rooms in the 17 units were sampled on 1094 occasions and 3822 samples were collected. The percentage of rooms without fungus increased regularly between 1992 and 1999 (41.1% and 74.8%, respectively). The units were classified according to the fungal contamination during the eight years: the operating theatres which required the highest protection (cardiological, thoracic, vascular, hand, orthopaedic and neurosurgery) and the adult haematological unit showed least contamination (71.8% rooms were negative). The most frequent species isolated were Penicillium spp. (28.4%), Cladosporium spp. (15.6%) and Aspergillus spp. (7.6%). Aspergillus fumigatus was rarely isolated (3.7%), and was mainly isolated at the beginning of the study. This study demonstrates that environmental control programmes are effective in reducing environmental mould contamination and could be useful in establishing exposure guidelines, especially by defining an acceptable level of biocontamination in zones at risk.

Sampling of Aspergillus spores in air

Nosocomially acquired aspergillosis typically occurs in the setting of treatment for leukaemia or other haematological malignancy. As Aspergillus species can be readily found in the environment, it has been widely believed that aspergillosis occurs as a consequence of exogenous acquisition of the fungus. Stringent environmental controls in transplant units have included high-efficiency air filtration, positive-pressure ventilation and frequent room air changes. Although there have been several well-documented examples of aspergillosis outbreaks as a result of hospital demolition and reconstruction, it has not always been possible to demonstrate elevated spore counts in clinical areas during building work. The sampling of air for Aspergillus is very problematic. Careful attention must be given to the design of air sampler, sampling protocols and an understanding of air sampling data. This review outlines many of the physical and environmental parameters that influence meaningful air sampling and recommends a simple procedure that has been tried and tested in many aspergillosis outbreaks.