Extended spectrum beta-lactamases (ESBL) are enzymes able to inactivate beta-lactam antibiotics

such as penicillins, cephalosporins and monobactams by hydrolysis. ESBL are defined as enzymes that can be transferred, mainly on plasmids, hydrolyse third generation cephalosporins and are inhibited by clavulanic acid, tazobactam or sulbactam [1]. There are three major groups of ESBL enzymes; TEM, SHV and CTX-M and these can be further divided into subgroups. ESBL enzymes are predominantly found in the bacterial species Klebsiella pneumoniae and Escherichia coli but may also be found in other species of Enterobacteriaceae. These bacteria are common causes of VX-680 manufacturer urinary tract TGF-beta tumor infections (UTI) and Erismodegib research buy may also cause sepsis, respiratory tract- and intra-abdominal infections [1]. ESBL-producing organisms have previously been associated with nosocomial infections but community-acquired infections mainly due to CTX-M-producing E. coli are emerging [2]. The majority of all ESBL-producing bacteria are isolated from urine samples and most of these bacteria are E. coli[3]. Treatment of infections caused by ESBL-producing bacteria is often complicated due to concomitant resistance to other classes of antibiotics

such as fluoroquinolones, aminoglycides, trimethoprim/sulfamethoxazole and tetracyclins [4]. The prevalence of ESBL-producing uropathogenic bacteria has increased in the last decades. In southern Europe, 21% of the community [5] and 18% of the nosocomial [6] urinary tract infections (UTI) are caused by ESBL-producing E. coli. The host-responses to infection ADP ribosylation factor by uropathogenic E. coli (UPEC) are characterized by neutrophil migration into the tissue and production of pro-inflammatory cytokines [7]. The early response of effector cells such as uroepithelial cells and neutrophils to UPEC may influence

bacterial clearance and thereby the outcome of the infection. It is not yet established whether ESBL-producing isolates have different virulence properties or pathogenic potentials than non-ESBL producers. Studies performed on expression of virulence factors and phylogenetic groups among ESBL-producing E. coli strains have not been conclusive [2, 8]. Furthermore, data on the effect of ESBL-producing strains on activation of host effector cells are limited. Some studies have showed that ESBL-producing K. pneumoniae are able to impair the respiratory burst of polymorphonuclear leukocytes (PMN) [9] and have a higher ability to invade ileocecal- and bladder epithelium [10] compared to non-ESBL-producing strains. A higher proportion of ESBL-producing K. pneumoniae strains were reported to be serum-resistant and therefore able to withstand the bactericidal effect of serum [11]. ESBL-producing E. coli have been reported to stimulate higher production of pro-inflammatory cytokines from human monocytes compared to susceptible E. coli[12].