Antibiotic resistance.

During the past 20 years, increasing frequencies of the emerence and spread of antibiotic-resistant bacterial pathogens ecame a health care problem worldwide. This is particularly documented by continuously perormed surveillance systems such as the European EARSnet http://ecdc.europa.eu/en/activities/surveillance/EARS-Net/about ARS-Net/Pages/about network.aspx) which collects and analses data on antibiotic resistance for blood culture isolates of ajor bacterial pathogens from sentinel hospitals in 28 Euroean countries. After the dramatic increase of the proportion f methicillin-resistant Staphylococcus aureus (MRSA) among S. ureus during the 1990s in most of the European countries as ell as in both Americas and in Asia besides the Netherlands and he Scandinavian countries, it seems to stabilize or even decline. owever, in 8 out of 28 European countries it is still above 25%! The proportion of Escherichia coli resistant to third-generation ephalosporins within 6 years only increased from 2% in 2004 to .5% in 2011. In more than 90% of these isolates this is obviously ased on extended-spectrum -lactamases (ESBL). Most of the ata on these E. coli isolates originate from the same hospitals at hich a stabilizing or declining MRSA situation was recorded. This bservation underlines that prevention of further dissemination f ESBL needs more than already done against MRSA! Besides actams, fluoroquinolones are the second most prescribed class of ntibiotics. In E. coli the proportion of isolates exhibiting resistance ncreased up to 21%, about 4% of them are multiple resistant with espect to aminopenicillins, third-generation cephalosporins, and o fluoroquinolones. In Klebsiella pneumoniae the proportion of isoates resistant to third-generation cephalosporins reached 21% in 010, that of multiple resistant ones 19%. In case of infections, carapenems are the alternatives of choice. Consequently, increasing roportions of ESBLs are followed by emergence of carbapenem esistance. Although this resistance is altogether still infrequent in ost of the European countries, its remarkable emergence in 5 out f 26 countries is following a development already known in paricular from the Near East and from countries in the South and in he East of Asia. Different from the situation for MRSA, where a umber of antibiotics were newly introduced during the past 12 ears, there are hardly alternatives for treatment of infections with ultiple and carbapenem-resistant gram-negative pathogens. This s not only seen in K. pneumonia but also in Acinetobacter baumannii nd Pseudomonas aeruginosa. Above all, the progress in genomics has contributed to a better nderstanding of the molecular mechanisms antibiotic resistance is ased on, namely of intrinsic resistance and of particular resistance enes acquired by horizontal transfer. We have learned about the