393 Medicina (Kaunas) 2013;49(9) ClInICal InVestIgatIons Medicina (Kaunas) 2013;49(9):393-8 Correspondence to A. Giedraitienė, Department of Microbiol- ogy, Medical Academy, Lithuanian University of Health Sci- ences, Eivenių 4, 50161 Kaunas, Lithuania E-mail: agne.giedraitiene@lsmuni.lt CtX-M-Producing Escherichia coli in lithuania: associations between sites of Infection, Coresistance, and Phylogenetic groups Agnė Giedraitienė 1 , Astra Vitkauskienė 2 , Virginija Ašmonienė 3 , Rita Plančiūnienė 1 , Sandrita Šimonytė 1 , alvydas Pavilonis 1 , guillaume arlet 4, 5 1 Department of Microbiology, Medical Academy, Lithuanian University of Health Sciences, Lithuania, 2 Department of Laboratory Medicine, Medical Academy, Lithuanian University of Health Sciences, Lithuania, 3 Laboratory of Neuro-oncology and Genetics, Neuroscience Institute, Lithuanian University of Health Sciences, Lithuania, 4 Laboratoire de Bacteriologie, UFR de Médecine, Universite Pierre et Marie Curie Paris 6, France, 5 Service de Bacteriologie, Hopital Tenon AP-HP, France Key Words: phylogenetic groups; site of infection; multiresistance; E. coli isolates; CTX-M. Summary. Increasing resistance of Escherichia coli (E. coli) to antibiotics, especially to the third-generation cephalosporins, has prompted studies on widespread resistance genes such as bla CTX-M and differentiation of E. coli to phylogenetic groups. The aim of this study was to determine the associations between the CTX-M type and the phylogenetic group, the site of infection, and coresistance in Lithuanian E. coli isolates producing β-lactamases. Material and Methods. A total of 90 E. coli ESBL strains were recovered from the lower res- piratory tract, the urinary tract, sterile body sites, wounds, and other body sites between 2008 and 2012. The E. coli isolates resistant to at least 2 antibiotics with different modes of action along with resistance to cefotaxime were considered as multiresistant. The bla CTX-M, bla TEM, bla OXA-1 , and bla SHV genes, the phylogenetic groups, and the resistance profiles were analyzed. Results. Of the 90 isolates, 84 (93.3%) were classified as multiresistant and 6 (6.6%) as re- sistant. The bla CTX-M-15 gene was the most prevalent gene followed by the bla CTX-M-14 and bla CTX-M-92 genes. The logistic regression analysis revealed the associations between CTX-M-15 and resistance to ceftriaxone, between CTX-M-14 and resistance to cefoxitin, aztreonam, ampicillin/sulbactam, ticarcillin/clavulanic acid, and tobramycin, and between CTX-M-92 and resistance to cefepime, piperacillin/tazobactam, gentamicin, and tobramycin. Conclusions. The results of this study showed a significant association between CTX-M-15, CTX-M-14, and CTX-M-92 β-lactamases and resistance to some antibiotics as well as CTX-M-14 β-lactamase and phylogenetic group A in the Lithuanian population. The associations between the CTX-M type and the site of infection were not determined. Introduction Escherichia coli (E. coli) is the most common mi- croorganism isolated from the sites of extraintesti- nal, intra-abdominal, community-acquired urinary tract infections and bacteremia (1, 2). Increasing resistance of E. coli to antibiotics, especially to the third-generation cephalosporins, has prompted stud- ies on widespread resistance genes such as bla CTX-M (3) and differentiation of E. coli strains to phyloge- netic groups (4). CTX-M β-lactamases encoded by bla CTX-M genes have almost replaced classical TEM- and SHV-type extended-spectrum β-lactamases (ESBLs). There are more than 120 different types of CTX-M β-lactamases that can be divided into 5 groups: CTX-M-1, -2, -8, -9, and -25 (5). E. coli strains can be assigned to 4 main phy- logenetic groups: A, B1, B2, and D. Phylogenetic group B2 is common among community-acquired isolates, whereas phylogenetic group D is associated with hospital-acquired isolates. Isolates recovered from the sites of extraintestinal infections most fre- quently belong to both of these groups (6, 7). Phy- logenetic groups A and B1 are associated with the sites of infection other than the urinary tract (7). Molecular epidemiological analyses of CTX- M ESBLs have been carried out in most Europe- an countries (6). Cefuroxime-resistant E. coli and Klebsiella pneumoniae isolates from Finland have been found to produce CTX-M-1 and CTX-M-9 β-lactamases alone and in combination with TEM- 1 β-lactamase (2). During outbreaks of Salmonella typhimurium, the CTX-M-5 enzyme has been de- scribed and identifed in Latvia (8), Belarus, and Russia (9). The CTX-M-3 and CTX-M-15 enzymes