Microorganism considerations Microorganisms vary in their degree of susceptibility to disinfectants. In general, Gram-positive bacteria are more susceptible to chemical disinfectants while mycobacteria or bacterial endospores are more resistant.
Different groups of bacteria vary in their susceptibility to biocides, with bacterial spores being the most resistant, followed by mycobacteria, then Gramnegative organisms, with cocci generally being the most sensitive.
Gram-positive bacteria, those species with peptidoglycan outer layers, are easier to kill - their thick peptidoglycan layer absorbs antibiotics and cleaning products easily. In contrast, their many-membraned cousins resist this intrusion with their multi-layered structure.
For example, spores are resistant to disinfectants because the spore coat and cortex act as a barrier, mycobacteria have a waxy cell wall that prevents disinfectant entry, and gram-negative bacteria possess an outer membrane that acts as a barrier to the uptake of disinfectants 341, 343-345.
For example, spores are highly resistant to disinfectants and, therefore, hardest to kill because of their spore coat and outer shell, which act as a natural barrier. This is not something that is acquired or changes over time.
Different groups of bacteria vary in their susceptibility to biocides, with bacterial spores being the most resistant, followed by mycobacteria, then Gram-negative organisms, with cocci generally being the most sensitive.
The Gram-negative bacteria were found to be more resistant to disinfection compared with the Gram-positive bacteria. Fig. 1 shows that 0.7% biocide in solution was the lowest concentration investigated that exhibited total inhibition of Gram-positive bacteria.
When exposed to antibacterial or antimicrobial cleaning products, most bacteria will die, but some may survive and multiply. These strains can become resistant to antibiotics and disinfectants.
Gram-negative bacteria are generally more resistant than gram-positive bacteria to disinfectants & antiseptics. Mycobacteria, endospores, & protozoan cysts & oocyst are very resistant to disinfectants & antiseptics.
Vegetative bacteria are the most susceptible to antimicrobial agents, while bacterial endospores are highly resistant. Mycobacteria and protozoan cysts exhibit varying levels of resistance but are still less resistant than endospores. Thus, the answer is A. Vegetative bacteria.
Iodine Compounds. Although less reactive than chlorine, iodine solution has a broad spectrum of antimicrobial activity against both gram-negative and gram-positive bacteria, fungi, protozoa, and even bacterial spores [12], while it is not so effective as virucidal [50].
In Gram-positive bacteria, the cell wall has a thick peptidoglycan layer which is relatively porous, allowing substances to pass through it quite easily. In Gram-negative bacteria, this peptidoglycan layer is greatly reduced and is further protected by a second, outer membrane (Figure 10).
In general, Gram-positive bacteria are more susceptible to chemical disinfectants while mycobacteria or bacterial endospores are more resistant.
Any alteration in the outer membrane by Gram-negative bacteria like changing the hydrophobic properties or mutations in porins and other factors, can create resistance. Gram-positive bacteria lack this important layer, which makes Gram-negative bacteria more resistant to antibiotics than Gram-positive ones [5,6,7].
Many Gram-negative rods are opportunistic nosocomial pathogens. Resistance rates vary among different species and antibiotics. Escherichia coli and Proteus mirabilis are among the least resistant, whereas Enterobacter spp., Klebsiella spp., and P. aeruginosa show greater innate and acquired resistance.
Most chemical disinfectants readily inactivate vegetative bacteria (gram-positive, gram-negative) and enveloped viruses. Fungal spores and non-enveloped viruses are generally less susceptible. Mycobacteria, bacterial endospores, and protozoal oocysts are highly resistant to most disinfectants.
It cannot be relied upon to destroy, within a practical period, bacterial endospores, mycobacteria, fungi, or all small nonlipid viruses.
Strains of pathogens that've developed resistance to multiple drugs are the hardest to get rid of. Infections like MRSA and CREs are often resistant to more than one type of antibiotic, so finding one that's effective (or a combination of medications that work together) can be challenging and take a long time.
Arguably the most widely known drug-resistant infections is methicillin-resistant Staphylococcus aureus or MRSA. This resistant infection is often associated with hospitals. Others you may have heard of include C. diff (clostridium difficile), drug-resistant malaria and streptococcus pneumoniae.
Various microorganisms have medical significance, including bacteria, viruses, fungi, and parasites. Antibiotics are compounds that target bacteria and, thus, are intended to treat and prevent bacterial infections.
Bacterial spores have the highest resistance to disinfectants, followed by mycobacteria, Gram-negative bacteria, and cocci (Russell, 1999).
Certain environmental factors can affect disinfectants. Be aware of those that can influence success. Presence of organic material: Feces/manure, body fluids, such as saliva, dirt and other debris on surfaces is one of the most common factors for disinfection failure.
pneumoniae, E. coli and Enterobacter spp. [10]. These pathogens are resistant to multiple antibiotics and can cause severe and often fatal infectious diseases such as bloodstream infections and pneumonia [9].