550. Carbapenem--Resistant E. coli and A. baumannii Among Catheter-Related Blood Stream Infection Patients in Egyptian ICUs

BACKGROUND: The spreading of E. coli and A. baumannii in hospitals is a growing concern due to increased resistance to carbapenems and Fluoroquinolones. The present study aimed to specifically evaluate the presence of mutations in the gyrA and parC genes in Egyptian ICU and their correlation with carbapenem-resistant genes E. coli and A. baumannii isolates from patients in 4 tertiary care hospital in Egypt. METHODS: A total of 120 A. baumannii and E. coli clinical isolates were isolated from ICU patients in 4 tertiary hospitals in Egypt. The bacterial isolates were identified by VITEK-2 (Bio Merieux, France). Antimicrobial susceptibility testing was performed according to CLSI guidelines. Phenotypic detection of carbapenemase activity was done by carba-NP test, followed by molecular identification of carbapenemase encoding genes bla(NDM), bla(OXA-48) and bla(KPC) by multiplex PCR. The quinolone resistance-determining regions (QRDRs) of gyrA and parC genes were amplified by singleplex PCR followed by reverse and forward sequencing to detect the gene mutation. The DNA sequences were compared with the sequences of wild type of these genes available in GenBank database. Then, the obtained DNA sequences and their amino acid sequences were analyzed using bioinformatics tools. RESULTS: All isolates showed a high level of resistance among tested antimicrobial agents (cephalosporins, aminoglycosides, carbapenems, penicillins) that ranged from 36% to 100%. Carba-NP detected 43.59% of the carbapenem-resistant isolates. Multiplex PCR detected that 17.95%, 46.15% and 2.56% of isolates were harboring bla(KPC), bla(NDM) and bla(OXA-48) respectively. PCR and sequencing technique showed combined gene mutation in 8 carbapenem-resistant E. coli and A. baumannii isolates. The specific substitutions observed in gyrA were Cys173Arg, Cys174 Gly, Asp80Val, Tyr178ASP, Tyr84Gly, Glu85Lys, Ser172Leu and Asp176Asn. While, the specific substitutions observed in parC were point mutation 62 Arg, Phe60Leu, Ils66Val, Gln76Lys. Point mutation 62 Arg was observed in two A. baumannii isolates, whereas Ser172Leu mutation was observed in two E. coli isolates. CONCLUSION: The presence of carbapenem resistance genes in combination with single and multiple mutations in QRDR causes the presence of highly resistant E. coli and A. baumannii isolates in the Egyptian hospitals. DISCLOSURES: All authors: No reported disclosures.