A Study of Air Microbe Levels in Different Areas of a Hospital Gine ´s Ortiz Æ Genoveva Yagu ¨e Æ Manuel Segovia Æ Vicente Catala ´n Received: 4 November 2008 / Accepted: 23 February 2009 / Published online: 28 March 2009 Ó Springer Science+Business Media, LLC 2009 Abstract Airborne transmission is an important route for many microbial pathogens in outdoor and indoor environ- ments, including hospitals. A 2-year-long survey of bioaerosol quality in operating theatres (OT), hospital rooms (HR) and maternity wards (MW) at a hospital in Murcia, Spain, was performed. Total aerobic counts (TAC) and fun- gal load (FL) were assessed using a microbiological air sampler (MAS-100 single-stage impactor). While fungal levels were below 1 cfu/m 3 (0–7.33 cfu/m 3 ) in OT, they were higher in MW (mean, 6.9 cfu/m 3 ; range 0.44–44.67 cfu/m 3 ) and in HR (mean, 10.6 cfu/m 3 ; range, 0–266 cfu/m 3 ). In OT the aerobic counts were considerably higher, with a mean of 25.6 cfu/m 3 (range, 1.67–157 cfu/m 3 ). MW and HR also showed higher means for total aerobic counts compared to OT. Seasonal changes were not detected in mould and bac- teria levels in OT. Hospital renovation occurred during this study and OT adjacent to renovated areas were closed. A survey of TAC and FL in OT resumed when renovation was completed. We observed an outstanding increase in FL (more than 100 cfu/m 3 ), particularly Aspergillus spp., during this period, but no significant changes in TAC were observed after renovation. Introduction Fungi grow in organic matter on surfaces, and their spores are dispersed in the air. While they are ubiquitous in the environment, and apparently harmless to healthy people, they can be deadly to immunocompromised individuals [14]. For this reason, hospital-acquired fungal infections are viewed as a greater threat to human health as people with cancer, advanced diabetes and HIV infection live longer. A progressive increase in morbidity and mortality associated with, for example, hematopoietic stem cell transplantation is an obvious source for concern [29]. It is important that hospital rooms (HR) where immunocom- promised patients (e.g. transplant recipient, HIV-infected or cancer patients) are placed and operating theatres (OT) remain free of airborne, opportunistic fungi. Aspergillus moulds are ubiquitous, and invasive asper- gillosis is the most common mould infection [32]. A relationship between environmental fungal contamination in hospitals and the incidence of invasive aspergillosis has been demonstrated [1] and, although this infection occurs mainly in immunocompromised patients, more than 500 cases of post-operative aspergillosis in immunocompetent individu- als have also been reported [25]. Aspergillus fumigatus and A. flavus are the leading species of the genus causing inva- sive aspergillosis [24]. Outbreaks of nosocomial aspergillosis are attributed to airborne sources and even small concentrations of spores have been associated with outbreaks [33]. Since treatment of aspergillosis is difficult an outcome is often fatal, so vigilance in implementing pre- ventive measures is of major importance to human health. Fungi are not the only airborne threats to human health in hospitals. Inhalation of airborne bacteria or some of their components may result in adverse health effects [5] including hypersensitivity and pneumonia [12]. Total aer- obic count (TAC) reflects bacterial load and is an indicator of the microbiological quality of an environment. In order to avoid infections caused by airborne microorganisms it is very important to maintain G. Ortiz (&) Á V. Catala ´n LABAQUA, Olof Palme 12, 30009 Murcia, Spain e-mail: gines.ortiz@labaqua.com G. Yagu ¨e Á M. Segovia Servicio Microbiologı ´a. Hospital Virgen de la Arrixaca, Murcia, Spain 123 Curr Microbiol (2009) 59:53–58 DOI 10.1007/s00284-009-9398-7