MIC is the minimum conc of any substance that inhibits all types of organisms in a culture while MBC is the minimum conc of any substance that kills bacteria particularly. So MIC may equal MBC but MBC may not equal MIC.

This is actually quite common for many bactericidal compounds.

Thank you Jaya and Michael....are there any literature recommended for reading on such occurrence? Perhaps I'm searching with inaccurate key words...

MIC is dependent on the chemicals and the organism cultured. An MIC streaked on agar showing no growth indicate complete bactericidal/antimicrobial activity and presence of growth indicate that the action of the substance is only inhibitory.

MIC as the name implies does not necessarily mean total killing. If the antimicrobial used has cjdal effect, the test bacteria will be killed at specific conc, however, some mutant cells of the same bacterium might still be viable because they have developed resistance to the antimicrobial.

Thank you Buenaflor and Tajudeen.

The other problem with an MIC is that it is usually time-specific: i.e. no growth in 24 hours. We use isothermal microcalorimetry (IMC) to study the effect of substances on microbes. With IMC, it is simple to just wait for a heat signal indicating microbial growth. Our experience is that in many cases, a concentration giving an MIC at 24 hours will exhibit growth later--e.g. at 48 hours. You might want to take a look at both

https://en.wikipedia.org/wiki/Isothermal_microcalorimetry#Microbiology

and

https://en.wikipedia.org/wiki/Isothermal_microcalorimetry#Pharmacodynamics

Thanks! this is very interesting and an advanced approach researchers can look into...

I have come across another system used in a government hospital here in Malaysia to screen detect microbial growth in patients' blood whom were suspected of infection by doctors. It is an incubator that detects changes to carbon dioxide levels of the blood samples in bar coded bottles with added additives. After a certain incubation period samples with increase carbon dioxide levels will be detected by a sensor in the incubator indicating possible microbial growth. The lab staff would then remove these bottles and perform SOP guided protocols to culture the blood and follow-up with biochemical tests to identify the organism to aid treatment options. I guess these are can be good approaches to be used in accurate IC determination.

I would like to ask for further explanation for the first commnet given by Dr Kurhekar regarding the statement, "So MIC may equal MBC but MBC may not equal MIC". What does that means? Thank you :-)