Acquired carbapenemases pose one of the most pressing public health threats relating to antibiotic resistance. In most countries, the number of carbapenemase-producing bacteria from human clinical specimens is rising, and the epidemiological status of these multiresistant bacteria is progressively worsening. Furthermore, there is a growing number of reports of carbapenemases found either in bacteria isolated from non-human sources or in Salmonella enterica subsp. enterica, a zoonotic species. However, carbapenemases are not yet systematically sought in bacteria from non-human sources, reports of them are largely observational, and there is limited investigation of carbapenemase-positive bacteria in animals and possible links with people who may have acted as potential sources. Active surveillance and monitoring for carbapenem-resistant bacteria in the food chain and other non-human sources is urgently needed, with an enhanced and rigorous follow-up of all positive results. The carbapenems are currently our last good defence against multiresistant Gram-negative bacteria. Our ability to limit the rise and spread of carbapenemase producers, which occur only at basal levels in many countries at present, should serve as a key performance indicator for the success or failure of the efforts that have been called for by international organizations and governments to reduce the impact of antibiotic resistance
In 2009, 1462 Escherichia coli isolates were collected in a systematic resistance monitoring approach from primary production, slaughterhouses and at retail and evaluated on the basis of epidemiological cut-off values. Besides resistance to antimicrobial classes that have been extensively used for a long time (e.g. sulphonamides and tetracyclines), resistance to (fluoro)quinolones and third-generation cephalosporins was observed. While in the poultry production chain the majority (60%) of isolates from laying hens was susceptible to all antimicrobials tested, most isolates from broilers, chicken meat and turkey meat showed resistance to at least one (85-93%) but frequently even to several antimicrobial classes (73-84%). In the cattle and pig production chain, the share of isolates showing resistance to at least one antimicrobial was lowest (16%) in dairy cows, whereas resistance to at least one antimicrobial ranged between 43% and 73% in veal calves, veal and pork. Resistance rates to ciprofloxacin and nalidixic acid in isolates from broilers were 41.1% and 43.1%, respectively. Likewise, high resistance rates to (fluoro)quinolones were observed in isolates from chicken meat and turkey meat. In contrast, ciprofloxacin resistance was less frequent in E. coli isolates from the cattle and pig production chain with highest rate in veal calves (13.3%). Highest resistance rates to cephalosporins were observed in broilers and chicken meat, with 5.9% and 6.2% of the isolates showing resistance. In dairy cattle and veal, no isolates with cephalosporin resistance were detected, whereas 3.3% of the isolates from veal calves showed resistance to ceftazidime. Resistance to (fluoro)quinolones and cephalosporins in E. coli isolates is of special concern because they are critically important antimicrobials in human antimicrobial therapy. The emergence of this resistance warrants increased monitoring. Together with continuous monitoring of antimicrobial usage, management strategies should be regularly assessed and adapted.
Im Jahre 2011 hat die EFSA die Risiken für den Verbraucher durch ESBL-/AmpC-bildende Keime in Lebensmitteln und Lebensmittel liefernden Tieren bewertet. Die Mensch-zu-Mensch-Übertragung in Krankenhäusern und in der Allgemeinbevölkerung wurde zu diesem Zeitpunkt hauptsächlich für die Verbreitung von ESBL-bildenden E. coli verantwortlich gemacht. ESBL-/AmpC-bildende E. coli sind in Deutschland, wie in vielen Mitgliedsstaaten der Europäischen Gemeinschaft, bei Lebensmittel liefernden Tieren und tierischen Lebensmitteln weitverbreitet. Eine Abschätzung der Bedeutung Lebensmittel liefernder Tiere als Reservoir für ESBL-/AmpC-bildende E. coli sowie für die ESBL-kodierenden Resistenzgene muss die beobachtete Heterogenität in den Resistenzgenen, Plasmiden und Keimen bei Tieren, Lebensmitteln und beim Menschen berücksichtigen. Hierbei müssen die klonale Ausbreitung von Keimen und Aspekte des horizontalen Gentransfers von Resistenzgenen, z. B. über Plasmide, betrachtet werden. Während niederländische Studien vorwiegend Geflügel als wichtiges Reservoir identifiziert hatten, zeigt eine Studie aus Dänemark einen Transfer von ESBL-Gene tragenden Resistenzplasmiden auf den Tierhalter ausgehend von Schweinen. Erste Quantifizierungsansätze zur Bedeutung von Nutztieren als Reservoir für ESBL-bildende E. coli in Deutschland zeigen, dass sich die Anteile der häufigsten ESBL-Gene bei E. coli-Isolaten von Tieren und Menschen deutlich unterscheiden. Werden auch Eigenschaften der Bakterienstämme berücksichtigt, wie z. B. die phänotypischen Resistenzen gegen verschiedene Antibiotikaklassen, zeigt nur ein kleiner Anteil der Isolate vom Menschen vergleichbare Muster mit Isolaten vom Tier. Die bisherigen Ergebnisse machen auch deutlich, dass bestimmte ESBL-Typen bei allen betrachteten Nutztiergruppen vorkommen. Derzeit kann die überwiegende Mehrzahl der Besiedelungen des Menschen mit ESBL-bildenden E. coli nicht über die Tierhaltung und Lebensmittel liefernde Tiere erklärt werden. Dies verdeutlicht, dass die Übertragungswege komplexer sind und weitere Reservoire und Infektionsquellen, einschließlich der Interaktion zwischen Menschen, zukünftig Berücksichtigung finden müssen. ; In 2011 EFSA has evaluated the risk for the consumer caused by ESBL-/AmpC-producing bacteria in food of animal origin and in livestock animals. Human-to-human transfer in hospitals and in the community was considered as the most relevant route of transmission for ESBL-producing E. coli. ESBL-/AmpC-producing E. coli are in Germany, as in many other Member States of the European Union, widely spread in food of animal origin and in livestock animals. In an assessment of the relevance of livestock animals as reservoir for ESBL-/AmpC-producing E. coli as well as for ESBL-coding resistance genes the heterogeneity of the resistance genes, plasmids and bacteria in animals, foods and humans needs to be considered. In this context, both, the clonal spread of bacteria as well as horizontal transfer of resistance genes, e. g. by plasmids, have to be analyzed. Whereas studies in the Netherlands identified poultry as the most relevant reservoir, the transfer of ESBL-gene carrying plasmids from pigs to the farmers was demonstrated in Denmark. First attempts to quantify the relevance of livestock animals as reservoir for ESBL-producing E. coli in Germany showed, that the proportions of the most frequent ESBL-resistance genes are quite different between animal and human derived E. coli isolates. If in addition properties of the bacterial cells, e.g. resistance to several antibiotic classes are considered, only a small proportion of human isolates showed the same patterns as animal isolates. The results achieved so far demonstrate that certain ESBL-types are prevalent in all livestock populations investigated. Currently, the majority of cases of colonizations with ESBL-producing E. coli among humans cannot be directly linked to livestock and food-producing animals as reservoirs. This reflects that transmission routes are more complex and other reservoirs and sources including human-human interactions have to be taken into consideration.
