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Extended spectrum beta-lactmase (ESBL) producing organisms create a major problem for clinical therapeutics. The frequency of ESBL producing strains among clinical isolates has been steadily increasing over the past few years resulting in limitation of the therapeutic options. These resistant bacteria are emerging world wide as a threat to human health in both the community and hospital settings. -lactamase production by several organisms is the most important mechanism of resistance to beta-lactam antibiotics, such as penicillins and cephalosporins. This study was done to determine the susceptibility of different antimicrobials to ESBL producing Escherichia coli and Klebsiella pneumoniae isolated from wound swabs, blood, urine, fluid, tracheal aspirates and sputum in Shahid Bahonar Hospital of Tehran from July, 2007 to June, 2008. A total of 115 ESBLproducing isolates were obtained from outdoor and indoor patients. Out of 115 isolates, 60% were E. coli and 40% were K. pneumoniae. All ESBL-producing isolates were confirmed using the Clinical and Laboratory Standards Institute (CLSI)-approved double-disk diffusion method. 29.6% of these isolates were collected from medical wards and 24.3% were collected from outdoor. Urine (70.4%) was the main source of ESBL-producing isolates from all patients, followed by blood (16.5%). All isolates were susceptible to both imipenem and meropenem. Of all isolates, 93.9% were susceptible to amikacin. The cephalosporins (1-4 generations) were almost 100% resistant. For Nitrofurantoin, 57.4% were sensitive. High rate resistance (74.8%) was observed to all quinolones tested. Aztreonam, Ampicillin, Co-amoxyclav and Ampicillin/Sulbactam were 100% resistant. This study shows that the frequency of ESBL producing strains of E. coli and K. pneumoniae is high in both hospital and community levels and it has a significant implication for patients’ management. Advance drug resistance surveillance and molecular characteristics of ESBL isolates is necessary to guide the appropriate and judicious antibiotic use. Key words: Extended spectrum beta-lactamase (ESBL), Drug sensitivity, Escherichia coli, Klebseilla pneumoniae DOI: http://dx.doi.org/10.3329/bjmm.v4i1.8467 BJMM 2011; 4(1): 32-36

Civilian patients with severe burns were almost local and systemic cell host immune responses concurrent depression because of complications after microbial infections. The most abundant and harmful bacterial infections are associated with opportunistic bacteria Staphylococcus aureus and Pseudomonas aeruginosa, linked to nosocomial infection with prolonged stay in a hospital. Many virulence factors excrete from both species that facilitate adherence to the burned area, localized and invasion tissue, and the emergence of antibacterial resistance. Molecular docking of molecules assimilates the interaction between a ligand and its receptor the virulence factor; this project designed to show the extent of interaction between active component extracted from black tea and mint and virulence factors (coagulase, exozyme S, the extended-spectrum of beta- lactamase and beta-lactam binding protein) using molecular docking. Aqueous extracts of black tea and mint were analyzed by GC mass and each of the bioactive components was docked against each virulence factor. Re- rank score was monitored to explain the power of interaction between ligand and receptor.Results found here that components of black tea gave more re-rank score with all virulence factors; the most active was Myricetin that needs -80.906, -80.19, -69.04, and -67.06 for PBP2 protein, exozyne S, extended-spectrum beta-lactamase, and coagulase respectively. It was noticed that Myricetin was more active against proteins excreted from P. aeruginosa than that of S. aureus. Kaempferol as a second bioactive compound that gave a positive effect regarding its re rank score -90.195 and -79.54 when docked with PBP2 and exozyme S from P.aeruginosa.Molecular docking revealed that the aqueous extract of both black tea and mint have high re-rank as inhibitory substances against different virulence factors of S.aureus and P.aeruginosa that could be a good candidate for treating burns injuries.

Among the various beta-lactam antibiotics, carbapenems are the most potent and have been reserved for use in treating infections caused by multi-drug resistant (MDR) Gram negative bacilli, especially Pseudomonas. They are effective even against Extended Spectrum beta-lactamase (ESBL) and Amp C b-lactamase producing bacteria. The clinical utility of carbapenems is under threat with the emergence of carbapenem resistant bacteria due to production of carbapenem hydrolyzing metallo-beta-lactamase (MBL) which confers high-level resistance to all b-lactam antibiotics except aztreonam. The prevalence of MBLs have been studied in many countries but not been reported in Bangladesh. The purpose of the study to determine the presence of MBLs producing Pseudomonas in clinical samples from a tertiary care hospital. MBLs producing Pseudomonas in various clinical samples of an urban hospital of Dhaka city was investigated over a 6-month period (January 2009-June 2009). EDTA-IMP agar dilution minimum inhibitory concentration (MIC) reduction method was employed to detect MBL producing Pseudomonas sp. Out of 44 Pseudomonas isolates 08 (18.2%) were sensitive and 23 (52.3%) were resistant to imipenem while 13 (29.5%) were intermediate resistant (MIC = 8 μg/ml) to imipenem. All Pseudomonas showing intermediate resistance to imipenem were found sensitive by disc diffusion method. MBL phenotype was detected in 43%(10 out of 23) imipenem resistant Pseudomonas spp. while the rate was 61%(08 out of 13) is intermediate resistant strains by EDTA-IMP agar dilution MIC method. The results of the study indicated high prevalence of MBL producing Pseudomonas spp. in our hospital environment. Early detection of these MBL producing Pseudomonas is necessary to institute appropriate treatment and effective infection control measures. Key words: Metallo-ß-lactamase, Pseudomonas species, Gram negative bacilli. DOI: http://dx.doi.org/10.3329/bjmm.v4i1.8469 BJMM 2011; 4(1): 43-45