In vitro activity of tigecycline against local clinical isolates of some Enterobacteriaceae

Abstract

Infectious diseases that Enterobacteriaceae cause are spreading on a wide scale. Examples of these infections are  gastrointestinal tract infections, meningitis, pneumonia, septicemia, urinary tract infections, and wound infections.  Antibiotic resistance among Enterobacteriaceae is a critical problem that makes treatment difficult. Tigecycline is a  broad spectrum antibiotic that is effective against multi-drug resistant organisms (MDR) and may be beneficial in the  therapy of infections caused by Enterobacteriaceae. This study aims to evaluate the in vitro activity of tigecycline against  clinical isolates of Enterobacteriaceae species and detect the possible resistance mechanisms of them against βlactams. The sensitivity of different isolates to antibiotics was determined by standard disc diffusion method. Phenotypic  detection of resistance mechanisms such as extended spectrum β-lactamase (ESBL), AmpC, ESBL& AmpC co-producers  and metallo β-lactamase (MBL) β-lactamases enzymes producer isolates was investigated. A total of eighty three  Enterobacteriaceae clinical isolates were collected. The common bacteria isolated were Escherichia coli and Klebsiella  pneumoniae. Multidrug resistance was found in 59.04% of tested isolates. The isolates were resistant to  sulfamethoxazole-trimethoprim, ciprofloxacin, tetracycline and impenem. The highest resistance was found to  sulfamethoxazoletrimethoprim followed by ciprofloxacin, tetracycline and imipenem. Phenotypic detection of resistance  mechanisms revealed that 69.4% of clinical isolates were ESBL producers, 12.2% were AmpC producers, and 8.2% were  ESBL and AmpC co-producers, while 10.2% were MBL producers. There was no resistance found to tigecycline among all  Enterobacteriaceae isolates tested. This study showed that tigecycline has potent in vitro activity against ESBL, AmpC,  combined ESBL and AMPC and MBL β-lactamases producing Enterobacteriaceae.