Pharmacology

Bactericidal and fungicidal activity (suspension tests)
The antimicrobial activity of Microcyn has been demonstrated against a variety of microorganisims in several in-vitro studies. 

Microcyn has been tested against a variety of organisms, including the five most common bacteria found in hospitals (Mangram, 1999): Staphylococcus aureus, Coagulase-negative Staphylococcus spp. (such as Staphylococcus epidermidis), Enterococcus spp. (such as Enterococcus hirae), Escherichia coli, and Pseudomonas aeruginosa.  Microcyn demonstrated a 106 reduction after 15 seconds of exposure against all five organisms.

An in vitro time kill evaluation was performed using Microcyn versus challenge suspensions of 50 different microorganism strains (25 American Type Culture Collection [ATCC] strains and 25 clinical isolates of those same species) as described in the Tentative Final Monograph .12. After exposure for 30 seconds, there was a reduction of the bacterial load >5 log10 in the following samples: Pseudomonas aeruginosa, Escherichia coli, Enterococcus hirae, Acinetobacter baumanni, Acinetobacter species, Bacteroides fragilis, Enterobacter aerogenes, Enterococcus faecalis, Vancomycin-resistant Enterococcus (VRE), Haemophilus influenzae, Klebsiella oxytoca, Klebsiella pneumoniae, Micrococcus luteus, Proteus mirabilis, Serratia marcescens,  Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus pyogenes, and Candida albicans (BioScience Labs, Bozeman, Mont.). (Gutiérrez 2006).

Bactericidal and fungicidal activity (carrier tests)
In various tests, the bactericidal and fungicidal properties of Microcyn have been tested in accordance to EPA DIS/TSS guidelines. Under these conditions, Microcyn Technology has totally inhibited the growth of the following microorganisms: Mycobacterium bovis (OT #105401) in 5 minutes; P. aeruginosa (ATCC #15442), S. aureus (ATCC #6538), Salmonella choleraesuis (ATCC #10708), Methicillin-resistant S. aureus (MRSA, ATCC #33592); and Trichophyton mentagrophytes (ATCC #9533) in 10 minutes; and Vancomycin-resistant Enterococcus faecalis (VRE, ATCC#51299) in 15 minutes (ATS Labs, Eagan, MN).

Virucidal
Microcyn was tested to determine the virucidal characteristics against the Human Immunodeficiency Virus type 1 (HIV-1), Strain HTLV-IIIB, in accordance with the U.S. EPA DIS/TSS-07 guidelines. The virus was applied as a dried film on sterile, glass Petri dishes, followed by exposure to MCN for 10 minutes. Subsequently the virus was separated from the test substance by gel filtration and titrated by serial dilutions for infectivity assay. Conclusion: per dilution groups (7 groups: 101 through 107), 8 samples were observed and in no sample infective activity was detected. The reduction in viral titer was ≥ 3.75 log10 for all samples. Under the conditions of this investigation, Microcyn demonstrated complete inactivation of HIV-1 following a 10-minute exposure time, in accordance with virucidal requirements as defined by the EPA. [ATS labs, U.S.]

Other viral inactivation studies have shown that Microcyn reduces ≥ 3 log the load of Influenza A virus (A/HK68), Rhinovirus type 37 (ATCC VR1147 ) and Human coronavirus (ATCC 740) after 30 seconds of exposure (APPTEC –ATS labs, U.S.).

Sporicidal
Microcyn was tested to determine sporicidal characteristics against spores of Bacillus subtilis (ATCC #6633). The test was conducted in accordance with the BS EN 14347:2002 ‘draft’ standard. A spore solution with a concentration of 108 – 109 spores/mL was prepared from a purchased spore suspension. Test samples contained 1 mL of the spore solution, 1 mL water and 8 mL Microcyn. The spore solution was exposed for 15 minutes to Microcyn, after exposure the samples were plated and incubated for four days at 36 ± 1 °C.

Conclusion: Under the conditions of this experiment Microcyn was sporicidal against Bacillus subtilis spores. The reduction in spores was 6.5 log on average, thus completing the requirements of the applied test method. [Micromed Laboratories Inc., U.S.]

Microcyn does not kill spores by inactivation of some component of the spore’s germination apparatus, but by damaging the spore’s inner membrane such that Microcyn treated spores lyse rapidly upon spore germination. Microcyn also appeared to inactivate at least one enzyme, CwlJ, located in the spore’s outer layers. Microcyn killing of spores was not accompanied by the release of the spore’s large pool of dipicolinic acid (DPA). (Rose et al, 2006; Paul M et al, 2006)