Antimicrobial Use, Infection Control Measures & Bacterial Resistance: A Complex Relationship
No class of antibiotics is exempt from responsibility for resistance. In fact, several antibiotics frequently used to treat cSSSIs have been associated with the emergence of antimicrobial resistance.[7] Monnet et al. investigated the possible relationships between MRSA prevalence and antimicrobial drug use, using a time–series analysis.[8] They have demonstrated the relationship between the use of the antimicrobial classes examined (macrolides, third-generation cephalosporins and fluoroquinolones) and the percentage of MRSA observed. The data provide powerful statistical and visual evidence of a strong temporal relationship between antimicrobial drug use and the varying prevalence of MRSA over time.[8]
Specific antimicrobial exposure patterns associated with VRE have included metronidazole, second- and third-generation cephalosporins[9] and clindamycin.[10]
Findings of several studies include significant associations of ESBL-producing Enterobacteriaceae with fluoroquinolones and third-generation cephalosporin use[11] as well as MDR-P. aeruginosa emergence after imipenem/meropenem exposure.[12] A significantly greater likelihood of nosocomially-occurring imipenem-resistant Acinetobacter baumannii was also identified in the case–control study by Lee et al. in patients who had received imipenem (odds ratio [OR]: 9.18; 95% CI: 3.99–21.13) or third-generation cephalosporins (OR: 2.11; 95% CI: 1.13–3.95).[13] Landman et al. also identified such a trend (i.e., strong association of prior cephalosporin use in hospital patients infected with carbapenem-resistant A. baumanni).[14]
Other factors, such as inadequate infection-control measures (i.e., hand hygiene, isolation precautions and specific transmission-based measures), may amplify and disseminate this problem in hospitals.[15,16] Eagye et al. have published a retrospective, observational case–control study that observed a high proportion of meropenem-resistant P. aeruginosa as a consequence of ready transmission of this organism, which was already present as an environmental risk in their hospital, rather than by selective antimicrobial pressure promoting its development.[16] Although antibiotic use has been shown elsewhere to promote the development of resistance in P. aeruginosa, the authors' population of patients with high-level meropenem resistance had not received carbapenems (or any other class of agent) at a significantly different rate than those with susceptible organisms or no infection at all; in fact, carbapenem administration was nearly zero.[16] Even though the usage of imipenem, meropenem and/or ceftazidime is associated with subsequent acquisition of MDR A. baumannii in critically ill patients,[17] its extensive dissemination in hospitals results from modes of transmission via multiple contaminated surfaces and objects, as well as transiently colonized healthcare workers' hands.[18]
In summary, reduction of antimicrobial resistance in hospitals requires good stewardship of antimicrobial usage combined with strong infection control. In this context, it is mandatory to take into account each patient's individual risk factors for MDR pathogens in order to select the better antibiotic and improve the clinical outcomes (Table 1).[12–17]
Expert Rev Anti Infect Ther. 2010;8(9):1019-1036. © 2010
Expert Reviews Ltd.
Cite this: Resistant Pathogen-associated Skin and Skin-structure Infections: Antibiotic Options - Medscape - Sep 01, 2010.
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