Effect of liquid disinfectant Morigad® on the growth patterns of Staphylococcus aureus, Escherichia coli and Candida albicans

The antimicrobial properties of various use dilutions of Morigad (R) against some test and control strains of nosocomial infectious agents namely Escherichia coli, Staphylococcus aureus and Candida albicans were investigated by measurement of viability of the organisms using turbidometric studies and various diluents (sterile tap water (STW), sterile deionized water (SDW) and 10% rabbit serum) and cultivation on solid media. Results showed that loss of viability was faster in SDW, followed by STW, then 10% rabbit serum. A higher percentage of the resistant (control) strains S-1, E-1 and C-1 survived compared to the susceptible (test) strains S-2, E-2 and C-2. The viability of the cells in the disinfectant was also concentration dependent with the death rates (Kmin(-1)) higher in SDW than in STW and E. coli more susceptible followed by S. aureus and C. albicans. Measurement of microbial resistance using decimal reduction time (DRT) against the lethal effects of the disinfectant shows that the slopes were lower for the test organisms and higher for the control organisms, while E. coli (E-1 and E-2) had higher DRT, followed by S. aureus (S-1 and S-2) and then C. albicans (C-1 and C-2). Result also showed that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values from the different diluents used were highest for serum, followed by STW, while the lowest values were obtained from SDW. For the organisms investigated, E. coli had the highest MIC (0.042) and MBC (0.046) followed by S. aureus (MIC 0.034, MBC 0.038), while C. albicans demonstrated the lowest MIC (0.032) and MBC (0.034) values.