Majallah-i Dānishgāh-i ̒Ulūm-i Pizishkī-i Qum (Jan 2013)
Emergence of Novel Plasmid-mediated Beta-lactamase in Klebsiella pneumonia
Abstract
Background and Objectives: Antibiotic resistance is a major threat for human health that affects hospitalized patients worldwide; Hence, The World Health Organization (WHO) has chosen antibacterial resistance as its theme in 2011. Klebsiella pneumoniae is a gram-negative opportunistic pathogen and a common cause of nosocomial infections. These bacteria -especially in infants- are the cause of pneumonia, sepsis, meningitis, diarrhea and bacteremia. Increasing emergence of multidrug resistance (MDR) among Klebsiella pneumoniae nosocomial isolates has limited the appropriate therapeutic options for the treatment of infections caused by this pathogen. Beta-Lactamases are major defenses of gram-negative bacteria against antibiotics. Recently, the emergence of new β-lactamases such as NDM-1 (New Delhi metallo-β-lactamase-1), OXA-48 (Oxacillinase-48), OXA-181 (oxacillinase-181), KPC (Klebsiella pneumoniae carbapenemase), CTX-M-15 (Cefotaxime-M-15) confer resistance to the most antibiotics such as penicillins, carbapenems, cephalosporins, macrolides, aminoglycosides and sulfamethoxazole. Resistant genes are located on plasmids with different sizes and can be readily transferred between bacteria, from one human to another human, and even from one country to another. In 2011, it has been evaluated that the importance of some of these genes like NDM-1, KPCs is as AIDS, malaria and tuberculosis. These enzymes have emerged as an important threat for hospitalized patients. Some pathogens containing both KPC and NDM-1 may be mistakenly diagnosed as susceptible by conventional laboratory methods and hence they could have an important role in the emergence and spread of more resistant pathogens due to administration of ineffective drugs to patients. No vaccines have been found yet that prevent infections caused by carbapenemase-producing bacteria. Also, there is not enough information about frequency of these plasmid genes and their genetic profiles in Iran. Therefore, it is important to diagnose the Klebsiella pneumoniae strains producing resistant enzymes, especially NDM-1, for better treatment of patients and prevention of the spread of these genes to other bacteria via exact phenotypic and genotypic methods.
