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Escherichia coli, one of the most common pathogens causing urinary tract infections, has shown increased resistance to commonly used antibiotics. In this study we analyzed the β-lactamase profiles of 38 inhibitor-resistant E. coli isolates obtained from public hospitals at three different levels of healthcare in KwaZulu-Natal, selected on the basis of their resistance profiles to the three antibiotic/inhibitor combinations, viz., amoxicillin/clavulanate, ampicillin/ sulbactam and piperacillin/ tazobactam. The isolates were subjected to MIC determinations, IEF analysis, plasmid profile analysis, PCR of the different β-lactamase genes and sequencing thereof to detect the possible mechanism/s of resistance. A range of β-lactamases including two novel inhibitor-resistant TEM β-lactamases, TEM-145 and TEM-146 were detected in two isolates whilst a novel plasmid-mediated AmpC-type β-lactamase, CMY-20 was detected in three isolates. Other β-lactamases included OXA-1, TEM-55, SHV-2, CTX-M-l and TEM-1. Changes were detected in the chromosomal AmpC promoter/attenuator regions in one isolate. Diverse β-lactamase genes and plasmid profiles inferred extensive mobilization of β-lactamase genes causing the concern of limited therapeutic options in the face of increasing resistance. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2008.

Darbo tikslas – ištirti Lietuvoje realizuojamų gyvūninės kilmės žalių paukštienos produktų (kepenų) užterštumą atspariomis antimikrobinėms medžiagoms Escherichia coli rūšies bei Staphylococcus genties bakterijų padermėmis. Darbas atliktas Lietuvos sveikatos mokslų universitete, slėnio „Nemunas“ atviros prieigos centro mikrobiologinių tyrimų laboratorijoje. Iš paukštienos subproduktų (kepenų) buvo išskirtos ir identifikuotos 209 bakterijų padermės. Paplitimo dažnis E. coli: kalautienoje – 60 proc., vištienoje – 62,2 proc.; stafilokokų: kalakutienoje – 90 proc., vištienoje – 87,6 proc. Nustatytas šių bakterijų jautrumas įvairiems antibiotikams naudojant kokybinį tyrimų metodą, duomenis interpretuojant pagal EUCAST klinikinius lūžio taškus. E. coli išskirtos iš paukštienos subproduktų pasižymėjo dažniausiu atsparumu ampicilinui (64,2 proc.), ciprafloksacinui (25,4 proc.), sulfametoksazoliui-trimetoprimui (37,7 proc.), aztreonamui (23,9 proc.), cefoksitinui (22,4 proc.) bei kur kas retesniu atsparumu gentamicinui (6 proc.). Staphylococcus genties bakterijos dažniausiai buvo atsparios sulfametoksazoliui-trimetoprimui (57,4 proc.), penicilinui G (54,5 proc.), eritromicinui (28,7 proc.). Kiek retesnis atsparumas nustatytas tetraciklinui (13,9 proc.), cefoksitinui (atsparumas meticilinui) (11,9 proc.), gentamicinui (8,9 proc.) ir ciprofloksacinui (7,9 proc.). Tarp Staphylococcus spp. padermių buvo aptikta ir S. aureus padermės (kalakutienoje – 55,6 proc., vištienoje – 19,6 proc.)... [toliau žr. visą tekstą] / The aim of this study was to investigate contamination of raw puoltry products (liver) sold in retail markets by antimicrobial resistant Escherichia coli and Staphylococcus. The research was carried out at Microbiological Research Laboratory of open access Center “Nemunas” of Lithuanian University of Health Sciences. Two hundred and nine isolates from poultry liver were isolated and identified. The prevalence of E. coli was 60% in turkey and 62,2% in chicken, while staphylococci were found in 90% in turkey and 87,6% in chicken liver samples. The susceptibility of these bacteria to various antibiotics was estimated by using antibiotic disc method; the data obtained was interpreted according to clinical breakpoints presented by EUCAST. E. coli isolated from poultry were the most frequently resistant to ampicillin (64,2%), ciprofloxacin (25,4%), sulfamethoxazole-trimethoprim (37,7%), aztreonam (23,9%), cefoxitin (22,4%) and with a lesser extent to gentamicin (6%). Staphylococci demonstrated frequent resistance to sulfamethoxazole-trimethoprim (57,4%), penicillin G (54,4%) and erythromycin (28,7%). Slightly lower resistances were observed to tetracycline (13,9%), cefoxitin (11,9%), gentamicin (8,9%) and ciproflaxicin (7,9%). Staphylococcus aureus prevalence was determined in 55.6% of turkey and in 19,6% of chicken liver products. This species demonstrated frequent resistance to penicillin G (60% from turkey and 77,8% from chicken) and to sulfamethoxazole-trimethoprim (40% and 55... [to full text]

A systematic approach based on bacteriophage Lambda (Lambda Red) and flippase-flippase recognition targets (FLP-FRT) recombinations was proposed for genomic engineering of Escherichia coli. For demonstration purposes, DNA operons containing heterologous genes (i.e. pac encoding E. coli penicillin acylase and palB2 encoding Pseudozyma antarctica lipase B mutant) engineered with regulatory elements, such as strong/inducible promoters (i.e. Ptrc and ParaB), operators, and ribosomal binding sites, were integrated into the E. coli genome at designated locations (i.e. lacZYA, dbpA, and lacI-mhpR loci) either as a gene replacement or gene insertion using various antibiotic selection markers (i.e. kanamycin and chloramphenicol) under various genetic backgrounds (i.e. HB101 and DH5α). The expression of the inserted foreign genes was subject to regulation using appropriate inducers [Isopropyl β-D-1-thiogalactopyranoside (IPTG) and arabinose] at tuneable concentrations. The developed approach has paved an effective way to “tailor” plasmid-free E. coli strains with desired genotypes suitable for various biotechnological applications, such as biomanufacturing and metabolic engineering.

Diss. (sammanfattning) Stockholm : Univ., 2005. / Härtill 3 uppsatser.

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: Paul J. Berti. Includes bibliographical references.

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2007. / Härtill 5 uppsatser.

Thesis (Ph. D., Microbiology, Molecular Biology and Biochemistry)--University of Idaho, November 2006. / Major professor: Carloyn H. Bohach. Includes bibliographical references. Also available online (PDF file) by subscription or by purchasing the individual file.

Thesis (M.P.H.)--University of Texas Health Science Center at Houston, School of Public Health, 2008. / Source: Masters Abstracts International, Volume: 46-06, page: 3219. Adviser: Herbert L. DuPont. Includes bibliographical references

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves [122]-134).