Bacterial resistance disinfectants

Chapman, J. S. (1998). Characterizing bacterial resistance to preservatives and disinfectants. Int. Biodeterioration Biodegradation. 41, 3-i, 241-245. 

Russell, A. D. (1999) Bacterial resistance to disinfectants present knowledge and future problems./ Hosp Infect, 43 (Suppl), S57—S68. 

Adelowo O, Fagade OE, Oke AJ (2008) Prevalence of co-resistance to disinfectants and clinically relevant antibiotics in bacterial isolates from three hospital laboratory wastewaters in South-western Nigeria. World J Microbiol Biotechnol 24 1993-1997... 

SimSes LC, SimSes M, Vieira MJ (2010) Influence of the diversity of bacterial isolates from drinking water on resistance of biofilms to disinfection. Appl Environ Microbiol 76(19) 6673-6679... 

Treatment for herpes genitalis is only indicated in serious or frequently recurring disease, in the presence of immunodepression or if psychosocial circumstances dictate this. Primary and recurrent infection is treated for 5 days with an oral derivative of aciclovir, either valaciclovir 2 x 500 mg or famciclovir 3 x 250 mg. Partial or complete aciclovir resistance may develop. Prophylactic aciclovir may be indicated if the frequency of recurrence is >6 per year. Local care of lesion (cleansing, disinfecting creams) is indicated to prevent secondary bacterial infection. 

In terms of shape, the first of these are rod-shaped and are called bacilli (singular, bacillus). The bacilli often have small, whip-like structures known as flagella, with which they are able to move about. Some bacilli have oval, egg-shaped, or spherical bodies in their cells, known as spores. Under adverse conditions, such as dehydration, and in the presence of disinfectants, the bacteria may die, but the spores may be able to live on. The spores germinate when the conditions become favorable, and form new bacterial cells. Some are so resistant that they can withstand boiling and freezing temperatures and prolonged desiccation. See Fig. 1. 

Plastic pipes, even when flushed out with the most powerful disinfectants and germicides, have proven to be safe havens for some bacterial strains. Bactena-resistant piping is of major importance in pharmaceutical manufacture, Research is underway to find plastic piping that will reject the adhesion of bacterial slimes. Currently, alloy steels are widely used. The adherence of slimes to plastic pipes permits colonies of bacteria to multiply. A similar problem exists when patients are furnished with plastic implants orprosiheses Hospital water supplies must be continuously monitored. 

Sterilization of a membrane system is also required to control bacterial growth. For cellulose acetate membranes, chlorination of the feed water is sufficient to control bacteria. Feed water to polyamide or interfacial composite membranes need not be sterile, because these membranes are usually fairly resistant to biological attack. Periodic shock disinfection using formaldehyde, peroxide or peracetic acid solutions as part of a regular cleaning schedule is usually enough to prevent biofouling. 

Disinfectants are used in industrial establishments, hospitals, and homes to prevent infection. Common disinfectants can kill some fungi, lipid-containing viruses, gram-negative bacteria, and mycobacteria, but bacterial spores are resistant to disinfectants. Factors affecting the effectiveness of disinfectants are contact line, concentration, pH, and the presence of interfering substances such as lipids, rubber, or plastics. 

The effectiveness of a disinfectant also depends upon the age of the microorganism. For example, young bacteria can easily be killed, while old bacteria are resistant. As the bacterium ages, a polysaccharide sheath is developed around the cell wall this contributes to the resistance against disinfectants. For example, when using 2.0 mg/L of applied chlorine dosage, for bacterial cultures of about 10 days old, it takes 30 min of contact time to produce the same reduction as for young cultures of about one day old dosed with one minute of contact time. In the extreme case are the bacterial spores they are, indeed, very resistant and many of the chemical disinfectants normally nsed have little or no effect on them. 

Microorganisms vary tremendously in their susceptibility to chemical disinfectants. Prions, bacterial endospores and mycobacteria possess the most innate resistance, while many vegetative bacteria and some viruses appear highly susceptible (see Chapter 17). In addition, microorganisms adhering to surfaces as biofilms or present within other cells (e.g. legionellae within amoebae), may reveal a marked... 

Prions (section 2.2.7) are generally considered to be the infectious agents most resistant to chemical disinfectants and sterilization processes strictly speaking, however, they are not microorganisms because they have no cellular structure nor do they contain nucleic acids. Of the conventional microorganisms, bacterial spores are the most resistant to chemical treatment. The majority of antimicrobial... 

In many liquid-phase applications, the bacterial colonization of activated carbons can occur quite readily [67]. This colonization [68] is considered to result from (i) the adsorptive properties of carbon, which produce an increase in the concentration of nutrients and oxygen as well as the removal of disinfectant compounds (ii) the pore texture of the carbon particles, which provides the bacteria with a protective environment (iii) the presence of a large variety of functional groups on the carbon surface, which enhances the adhesion of microorganisms and (iv) the nature of the mineral matter content of the carbon, which can favor bacteria adhesion. In general, bacteria attached to carbon particles are very resistant to disinfectants. 

The application of photodynamic therapy (PDT) in treatment of bacterial infections will definitely continue to attract the attention of scientists. It is considered unlikely that bacteria develop resistance against singlet oxygen therefore, PDT may become a useful weapon to battle infections. For treatment of infections in the oral cavity, a smart toothpaste containing a photosensitizer that is selectively absorbed by bacteria is under development. This can be used in combination with a laser toothbrush designed recently (Moore, 1998). Sensitizers can further be incorporated into bandages for disinfection of wounds or in cellophane films used to wrap food (Moore, 1998). 

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