**1.10. Mechanisms of appearance and extension of resistance**

The main responsible for the emergence and extension of resistance are the indiscriminate use of antibiotics and the transmission of resistant microorganism between humans (or between human and environment). The antibiotics exert a selective ecological pressure on the bacteria, thus promoting the appearance of resistance germs. Inadequate practices of prevention of the infection along with inadequate hygienic measures will favor the extension of the bacteria. The strategies to avoid these phenomena are aimed at a better use of antibiotics (reducing the selective pressure) and optimizing the infection control measures (reducing the colonization pressure) [13, 14].

Some measures aimed at a rational use of antibiotics are the following:


While some measures of patient-patient transmission control are:


to optimize the use of current antibiotics with the intention of extending their useful life. An

Current Status of Colonization and Infection by Multiresistant Bacteria in the Spanish Intensive…

http://dx.doi.org/10.5772/intechopen.78236

43

• suitable doses, based on pharmacokinetic and pharmacodynamics data, taking into account that in critical patients the increase in volume of distribution, cardiac output and glomerular filtration requires the administration of doses that could be above the usual doses (cur-

• evaluate the need to maintain the started treatment: to remove unnecessary antibiotics by

• adequate duration of antimicrobial treatment (usually too long due to the absence of evidence of optimal duration and for fear of suspending it if the evolution of the patient is good).

Different strategies have been described and tested to avoid resistance to antibiotic. Rotation consists of restricting in an established way an antibiotic or a class of antibiotics during a certain period of time, to reintroduce it later; the aim is to reduce the selective pressure exerted on the microbial flora and to minimize the appearance of resistance to rotated antibiotics. Cycling is to prescribe antibiotics according to a pre-established a priori sequence. In scheduling, an antibiotic or antibiotic class is replaced by another antibiotic or class with a comparable antimicrobial spectrum; there is change to another antimicrobial without returning to the initial agent. In rotation, there is a circular pattern. The usefulness of these strategies is theoretical. Periodic modifications would limit the generation of resistances by avoiding prolonged exposures to the same antimicrobial agent; the restriction of an antibiotic can result in the compensatory potentiation of the use of other unrestrained agents, with a later increase of resistance to these second agents. Also, the elimination for the selective pressure by an antibiotic when withdrawing its use does not imply the eradication of the genetic material responsible of the resistance. Despite the theoretical benefits of these strategies, their results

Epidemiological surveillance consists of the systematic collection, analysis and interpretation of data about a problem related to public health. The implementation of multimodal prevention programs must have the following elements: identification of problems, implementation plan, involvement of managers, record of compliance with objectives and, finally, the analysis of obstacles that may arise. An essential aspect of these programs is learning: the absence of adherence to the measures of the program due to lack of information or insufficient learning

The antimicrobial stewardship programs bring together specialists in infectious diseases, clinical pharmacologists, clinical microbiologists, epidemiologists and other, sometimes also intensivists, all of them gathered for the purpose of an adequate prescription of antibiotics.

adequate administration of antibiotics should be based on the following principles:

• proper choice of antibiotic: based on local ecology and habitual patterns of resistance;

• early start (associated with microbiological cultures);

rently available antibiotics rarely cause serious adverse effects);

culture results, and if possible, to narrow the spectrum (de-escalation);

are contradictory, and none of them have showed real benefit so far [17].

But this is just one aspect of a complex problem like antibiotic resistance.

**1.12. Epidemiological surveillance: multimodal prevention program**

time should be avoided.


### **1.11. Proper antibiotic treatment**

The evolution of an infectious process depends on the characteristics of the initial focus, the hemodynamic parameters, host factors, the responsible pathogen, in vitro antibiotic susceptibility tests and the precocity of the appropriate antibiotic treatment. The use of antibiotics is, at the same time, part of the problem and the solution when we talk about antibiotic resistance. Unfortunately, the emergence of resistance is faster than the creation of new antibiotics by the pharmaceutical industry. In general, the solution involves a global reduction in the consumption of antibiotics, although it is necessary to implement control programs aimed at rationalizing their use.

A frequently forgotten fact is that the majority of antibiotic consumption is done at the extrahospital level (Primary Care and food industry) [16]; it is necessary to regulate its use. Up to 50% of antibiotics prescribed at the hospital level are unnecessary, many of them are broad spectrum. The inadequate use of antibiotics increases the mortality of patients with severe sepsis, subjects them to unnecessary adverse effects and generates unjustified expenses. On the other hand, it is of vital importance to define the role of prophylactic antibiotic treatment and also differentiate the systemic inflammatory response syndrome of any cause from a real infectious process.

The loss of sensitivity to antibiotics is to be solved with several strategies: to speed up the development of new antimicrobials—the initiative "10 × 20" of the IDSA; 10 new antimicrobians available on 2020; to improve the mechanisms of infection control in health centers; and to optimize the use of current antibiotics with the intention of extending their useful life. An adequate administration of antibiotics should be based on the following principles:

• early start (associated with microbiological cultures);

• hand washing;

42 Current Topics in Intensive Care Medicine

intravenous antibiotics);

**1.11. Proper antibiotic treatment**

rationalizing their use.

infectious process.

• contact isolation measures (very important in case of MRSA, ERV and germs producers of ESBL), even grouping the colonized/infected patients (cohorting) and having staff exclu-

• cutaneous decolonization/daily bath with chlorhexidine to colonized/infected patients

• decolonization of the upper respiratory tract and gastrointestinal tract. Several options: oropharyngeal decontamination with antiseptics (chlorhexidine); selective oropharyngeal decontamination (with nonabsorbable antibiotics applied to the oropharynx); and selective digestive decontamination (with nonabsorbable antibiotics applied to the oropharynx with

• surveillance of early infections by MRB (for early identification of these germs, control of

• to implement strategies of infection prevention in relation to invasive devices (reduce the

• to regulate and monitor the process of cleaning, disinfection and environmental sterilization.

The evolution of an infectious process depends on the characteristics of the initial focus, the hemodynamic parameters, host factors, the responsible pathogen, in vitro antibiotic susceptibility tests and the precocity of the appropriate antibiotic treatment. The use of antibiotics is, at the same time, part of the problem and the solution when we talk about antibiotic resistance. Unfortunately, the emergence of resistance is faster than the creation of new antibiotics by the pharmaceutical industry. In general, the solution involves a global reduction in the consumption of antibiotics, although it is necessary to implement control programs aimed at

A frequently forgotten fact is that the majority of antibiotic consumption is done at the extrahospital level (Primary Care and food industry) [16]; it is necessary to regulate its use. Up to 50% of antibiotics prescribed at the hospital level are unnecessary, many of them are broad spectrum. The inadequate use of antibiotics increases the mortality of patients with severe sepsis, subjects them to unnecessary adverse effects and generates unjustified expenses. On the other hand, it is of vital importance to define the role of prophylactic antibiotic treatment and also differentiate the systemic inflammatory response syndrome of any cause from a real

The loss of sensitivity to antibiotics is to be solved with several strategies: to speed up the development of new antimicrobials—the initiative "10 × 20" of the IDSA; 10 new antimicrobians available on 2020; to improve the mechanisms of infection control in health centers; and

outbreaks—imited in time—and situations of endemic increase of isolation);

use of central venous catheters, bladder catheters, orotracheal tubes, etc);

• the use of universal contact precautions is not clear in all patients admitted to ICU;

sively dedicated to the care of these infectious patients;

(despite the limitations of the current studies) [15];


Different strategies have been described and tested to avoid resistance to antibiotic. Rotation consists of restricting in an established way an antibiotic or a class of antibiotics during a certain period of time, to reintroduce it later; the aim is to reduce the selective pressure exerted on the microbial flora and to minimize the appearance of resistance to rotated antibiotics. Cycling is to prescribe antibiotics according to a pre-established a priori sequence. In scheduling, an antibiotic or antibiotic class is replaced by another antibiotic or class with a comparable antimicrobial spectrum; there is change to another antimicrobial without returning to the initial agent. In rotation, there is a circular pattern. The usefulness of these strategies is theoretical. Periodic modifications would limit the generation of resistances by avoiding prolonged exposures to the same antimicrobial agent; the restriction of an antibiotic can result in the compensatory potentiation of the use of other unrestrained agents, with a later increase of resistance to these second agents. Also, the elimination for the selective pressure by an antibiotic when withdrawing its use does not imply the eradication of the genetic material responsible of the resistance. Despite the theoretical benefits of these strategies, their results are contradictory, and none of them have showed real benefit so far [17].
