Antimicrobial contamination

RookUdge S.J., E.R. Bums, and J.P. Bolte (2005). Modeling antimicrobial contaminant removal in slow sand filtration. Water Research 39 331-339. 

S. J. Rooklidge, Environmental antimicrobial contamination from terr-accumulation and diffuse pollution pathways, Sci.Total Environ., 2004, 325, 1-13. 

Resistance to antimicrobial agents is of concern as it is well known that bacterial resistance to antibiotics can develop. Many bacteria already derive some nonspecific resistance to biocides through morphological features such as thek cell wall. Bacterial populations present as part of a biofilm have achieved additional resistance owkig to the more complex and thicker nature of the biofilm. A system contaminated with a biofilm population can requke several orders of magnitude more chlorine to achieve control than unassociated bacteria of the same species. A second type of resistance is attributed to chemical deactivation of the biocide. This deactivation resistance to the strong oxidising biocides probably will not occur (27). 

Povidone—iodine is a brown, water-soluble powder containing approximately 10% iodine. However, the amount of free iodine, which is responsible for the antimicrobial activity, is low in a concentrated solution, but is released as the solution is diluted (41). Concentrated solutions have actually been contaminated with bacteria (42). For use as an antiseptic, povidine—iodine is diluted with water or alcohol to a concentration of 1% iodine. Detergents are added if it is used as a surgical scmb. lodophors are important as broad-spectmm antiseptics for the skin, although they do not have the persistent action of some other antiseptics. They are also used as disinfectants for clinical thermometers that have been used by tuberculous patients, for surface disinfection of tables, etc, and for clean equipment in hospitals, food plants, and dairies, much as chlorine disinfectants are used. 

Of the other peroxygen compounds with antimicrobial activity, potassium monoperoxysulphate is the main product marketed for disinfectant use. It is used for body fluid spillages and equipment contaminated with body fluids, but its activity against mycobacteria and some viruses is limited. 

An abscess occurs if peritoneal contamination is localized but bacterial elimination is incomplete. The location of the abscess often is related to the site of primary disease. For example, abscesses resulting from appendicitis tend to appear in the right lower quadrant or the pelvis those resulting from diverticulitis tend to appear in the left lower quadrant or pelvis. A mature abscess may have a fibrinous capsule that isolates bacteria and the liquid core from antimicrobials and immunologic defenses. 

Primary peritonitis is treated with antimicrobials and rarely requires drainage. Secondary peritonitis requires surgical removal of the inflamed or gangrenous tissue to prevent further bacterial contamination. If the surgical procedure is sub-optimal, attempts are made to provide drainage of the infected or gangrenous structures. 

After acute bacterial contamination, such as with abdominal trauma where GI contents spill into the peritoneum, combination antimicrobial regimens are not required. If the patient is seen soon after injury (within 2 hours) and surgical measures are instituted promptly, antianaerobic cephalosporins... 

Acute intraabdominal contamination, such as after a traumatic injury, may be treated with a very short course (24 hours) of antimicrobials.25 For established infections (i.e., peritonitis or intraabdominal abscess), an antimicrobial course limited to 5 to 7 days is justified. Under certain conditions, therapy for longer than 7 days would be justified, e.g., if the patient remains febrile or is in poor general condition, when relatively resistant bacteria are isolated, or when a focus of infection in the abdomen still may be present. For some abscesses, such as pyogenic liver abscess, antimicrobials may be required for a month or longer. 

Surgical operations are classified as clean, clean-contaminated, contaminated, or dirty. Antimicrobial prophylaxis is appropriate for clean, clean-contaminated, and contaminated operations. Dirty operations take place in situations of existing infection and antimicrobials are used for treatment, not prophylaxis (Table 82-1). 

Source control Removal of the primary cause of an infection such as contaminated prosthetic materials (e.g., catheters), necrotic tissue, or drainage of an abscess. Antimicrobials are unlikely to be effective if the process or source that led to the infection is not controlled. 

An alternative packaging is the combination of food-packaging materials with antimicrobial substances to control microbial surface contamination of foods. For both migrating and nonmigrating antimicrobial materials, intensive contact between the food product and packaging material is required and therefore potential food applications include especially vacuum or skin-packaged products (Vermeiren and others 2002). 

All foodstuffs in the area of a release should be considered contaminated. Unopened items may be used after decontamination of the container. Opened or unpackaged items should be destroyed. Fruits and vegetables should be washed thoroughly with antimicrobial soap and water. Many pathogens can survive in food containers for extended periods. 

Direct Exposure In the event that an individual is at the scene of a known or suspected attack (e.g., white-powder letter, aerosol release, etc.), have them wash their hands and face thoroughly with antimicrobial soap and water as soon as possible. If antimicrobial soap is not available, use any available soap or shampoo. They should also blow their nose to remove any agent particles that may have been captured by nasal mucous. Remove all clothing and seal in a plastic bag. To avoid further exposure of the head, neck, and face to the agent, cut off potentially contaminated clothing that must be pulled over the head. Shower using copious amounts of antimicrobial soap (if available) and water. Ensure that the hair has been washed and rinsed to remove potentially trapped agent. The Centers for Disease Control and Prevention (CDC) does not recommend that individuals use bleach or other disinfectants on their skin. 

The goals of antimicrobial therapy are to control bacteremia and to establish the metastatic foci of infection, to reduce suppurative complications after bacterial contamination, and to prevent local spread of existing infection. 

Acute intraabdominal contamination, such as after a traumatic injury, may be treated with a short course (24 hours). For established infections (peritonitis or intraabdominal abscess), an antimicrobial course of at least 7 days is justified. 

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