title: [Influence of magnetic field on the growth of pathogen microorganisms isolated from the indoor environment at the Archivo Nacional de la República de Cuba].
abstract: BACKGROUND
  Electromagnetic pollution has been detected at the Archivo Nacional de la República de Cuba and the influence of extremely low frequency magnetic fields could be quantified with pathogenic microorganisms isolated from the indoor environment.
  
  
  OBJECTIVE
  To quantify the influence of an extremely low frequency magnetic field on the growth of pathogenic microorganisms isolated from the environment at the Archivo Nacional.
  
  
  METHODS
  We used five microorganisms isolated at the Archivo Nacional: Streptococcus sp. (1), Listeria sp. (2) and Candida guillermondii (3), and Escherichia coli ATCC 25922 (4) and Saccharomyces cerevisiae (5) as references. We applied this magnetic field of extremely low frequency, 60 Hz/220 V (3 mT), for two hours to these microorganisms on three culture tubes with distilled water and nutrient broth. Then we inoculated 0.1 mL in the following solid culture mediums on Petri dishes: CromoCen SC Agar (1 and 2), Potato Dextrose Agar (3), CromoCen DC 4227 (4) and Malt Extract Agar (5). The colonies were counted (log CFU/mL) by digital processing of the images of Petri dishes using the MatLab ® tool.
  
  
  RESULTS
  We observed a statistically significant stimulation (p=0.05) in the quantity of treated colonies as compared to controls, which was higher in nutrient broth than in distilled water, and in bacteria (nutrient broth and treated colonies: 9.43 to 10.62 CFU/mL) as compared with yeasts (nutrient broth-treated colonies: 8.31 to 8.79 CFU/mL). In decreasing order, stimulation was as follows: Listeria sp., E. coli ATCC 25922, Streptococcus sp., C. guillermondii and S. cerevisiae .
  
  
  CONCLUSIONS
  We concluded that the magnetic field applied had a stimulating effect on the microorganisms under study, which increases the risk to the health of staff and visitors at the Archivo Nacional .
authors: Instituto de Investigaciones para la Industria Alimentaria, La Habana, Cuba.
authors: Matilde
authors: M
authors: Anaya
authors: Departamento de Bioingeniería, Facultad de Ingeniería Eléctrica, Instituto Superior Politécnico José A. Echeverría, La Habana, Cuba.
authors: Eduardo
authors: E
authors: Barbará
authors: Departamento de Bioingeniería, Facultad de Ingeniería Eléctrica, Instituto Superior Politécnico José A. Echeverría, La Habana, Cuba.
authors: Jesús
authors: J
authors: Padrón
authors: Laboratorio de Conservación Preventiva, Archivo Nacional de la República de Cuba, La Habana, Cuba.
authors: Sofía F
authors: SF
authors: Borrego
authors: Laboratorio de Conservación Preventiva, Archivo Nacional de la República de Cuba, La Habana, Cuba.
authors: Oderlaise
authors: O
authors: Valdés
authors: Laboratorio de Conservación Preventiva, Archivo Nacional de la República de Cuba, La Habana, Cuba.
authors: Alian
authors: A
authors: Molina
mesh_terms: D001109:Archives; D001419:Bacteria / Q000254:growth & development* / Q000528:radiation effects; D058491:Bacterial Load; D003462:Cuba; D004197:Disease Reservoirs; D055615:Electrical Equipment and Supplies / Q000009:adverse effects*; D004783:Environmental Microbiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D060526:Magnetic Fields; D009172:Mycology / Q000379:methods; D016272:Occupational Health; D015003:Yeasts / Q000254:growth & development* / Q000528:radiation effects