الفهرس 
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Abstract
Extended spectrum β-lactamase (ESBLs) producing bacteria especially Klebsiella pneumoniae and Escherichia coli, have become one of the most important threats to whole world, especially developing country, due to their ability to spread rapidly and causing serious infections.
In this study, 168 clinical isolates provided from Al Kasr Al-Ainy hospital. These isolates were screened for ESBLs producers. All bacterial isolates identified by the standard microbiological methods including cultural morphology, microscopic examination and biochemical tests which indicated that the isolates were 85 K. pneumoniae and 83 E. coli. Out of 168, 113 were phenotypically ESBLs producers (67.26%) which confirmed by DDST and CDT tests. According to patients ages and gender among 113 positive ESBLs isolates, they classified as: 52 (46.0%) female patients (including: 42(37.2%) adult and 10(8.8%) children); and 61 (54.0%) male patients (including: 57(50.4%) adult and 4(3.5%) children).
The identification of isolates was confirmed by API 20E to 64 E. coli and 49 K. pneumoniae. The highest source of isolates was urine with 53.1%.
The susceptibility of isolates towards different antibiotics showed that, all isolates were sensitive to carbapenems (IPM) with 100% and (MEM) antibiotics with 95.92%, 96.88% forK. pneumoniae and E. coli, respectively. In addition, they were sensitive to cephamycin (FOX) with 97.96, 96.88% and to β lactam/β-lactamase inhibitor (TZP) with 71.42, 90.62% for K. pneumoniae and E. coli, respectively. However, all isolates were resistant to penicillin (AP) and cephalosporins group 3rd generation including (CTX, CRO and CAZ) except for 2 E. coli isolates were intermediate against CAZ, and only one K. pneumoniae isolate was intermediate against CAZ and another against CRO antibiotic.
Determination of MICs values confirmed that all ESBLs producing isolates (113) were >512 µg/ml for CTX while 128 to ≥ 512 µg/ml for CAZ.
PCR detection for selected bla genes (blaSHV, blaTEM and blaCTX-M) demonstrated that only 108 (95.92%) isolates were found to have one or more ESBLs genes. While 5 isolates did not contain any of the tested genes. Among the positive isolates, the prevalence of blaSHV, blaTEM andblaCTX-M genes were 82.4, 78.7 and 91.7%, respectively. For K. pneumoniae, blaSHV, blaTEM, and blaCTX-M genes were 97.87, 80.85 and 91.49%, respectively. While for E. coli isolates, the prevalence of blaSHV, blaTEM, and blaCTX-M genes was 70.49, 77.05 and 91.8%, respectively.
Moreover, the coexistence of the 3 genes was detected in 72.34% and 47.54 of K. pneumoniae and E. coli, respectively.
Nucleotide sequence analyses of blaTEM (K.p.1 and E.c. 2), blaCTX-M (K.p.38 and E.c. 60) and blaSHV (K.p.46 and E.c. 40) genes were carried out and submitted to GenBank under the accession numbers MN096660, MN96661, MN096662, MN096663, MN096664 and MN096665, respectively.
SDS-PAGE of total proteins showed bands > 34 KD in all isolates, which may play role in carbapenem sensitivity.
These data contributed to better knowledge of the epidemiology of ESBLs producing bacteria and alarming to develop other strategies to minimize the spread of antibiotic resistant pathogens.