Prevalence of AmpC β -Lactamase-Producing Pseudomonas aeruginosa Isolates From Feacal Matter of Cow

Environmental microorganisms represent the most relevant reservoir of resistance to antibiotics in the community, and this is due in part to the undue exposure of these organisms to antimicrobial agents. AmpC β-lactamases are clinically important cephalosporinases encoded on the chromosomes of bacteria in the Enterobacteriaceae family and some non-enteric bacteria including Pseudomonas aeruginosa, where they stimulate these organisms to be resistant to the cephamycins (cefoxitin for example) [1,2]. Gram negative bacteria that produce AmpC β-lactamases have been implicated in many cases of hospital and community acquired infection [1-3]. For enteric organisms with the potential for high-level AmpC β-lactamase production by mutation, the development of resistance upon therapy especially to the cephamycins is a concern for public health since these agents are critical in the treatment and management of bacterialrelated infections in humans [4]. AmpC β-lactamase production in most Enterobacteriaceae including Klebsiella pneumoniae and Escherichia coli is low but the hyper-production of AmpC enzymes in these organisms is usually induced by the exposure of the bacteria to antibiotics [3]. AmpC β-lactamases can be expressed at high levels by mutation. The over expression of AmpC β-lactamases confers resistance to broad-spectrum cephalosporins including cefotaxime, ceftazidime, and ceftriaxone. It has been reported that transmissible plasmids have acquired genes for AmpC β-lactamases, which consequently can now appear in bacteria lacking or poorly expressing a chromosomal AmpC β-lactamase gene as is seen in E. coli, K. pneumoniae, and Proteus mirabilis [5]. The genes that confer or mediate the production of AmpC β-lactamases in Gram-negative bacteria are often chromosomallyborne rather than being plasmid encoded but these genes may still be plasmid-encoded in some bacteria [6]. The AmpC β-lactamases are clinically important beta-lactamases because they confer antimicrobial resistance to the narrow-spectrum, expanded-spectrum and the broad-spectrum cephalosporins and the penicillins; and their resistance is also expressed towards the βlactamase inhibitors such as amoxycillin-clavulanic acid [7,8]. Techniques to identify AmpC β-lactamase-producing isolates are available but are still evolving and are not yet optimized for the clinical laboratory, which probably now underestimates this resistance mechanism in either the community or hospital environment. Nevertheless, the timely and accurate detection of organisms harbouring genes responsible for the production of AmpC β-lactamases is critical for total patient care. The occurrence of AmpC-producing P. aeruginosa from abattoir calls for effective Volume 4 Issue 5 2017