Antipseudomonal β-Lactams Resistance in Iran

Abstract

Over the last years, the mortality rate of Pseudomonas aeruginosa, which is one of the major reasons for severe infections, has been significantly increasing. This bacterium is highly resistant to many antibiotics, especially carbapenems, thanks to its complicated mechanism by which it can acquire exogenous genes. The purpose of this research is to have a review of empirical studies surveying the P. aeruginosa resistance to beta-lactams in Iran in order to investigate the most reliable methods by which the incidence of P. aeruginosa infections can be decreased and controlled. We performed a systematic review of all articles published from 2008 until 2018. Studies which did not address P. aeruginosa resistance to beta-lactams were excluded from the analysis. Studies with less than 10 cases were also excluded. Studies with more than ten cases, which did not have repetitive information, were taken into account for the final selection; 133 out of 893 articles were chosen. The resistance rate of P. aeruginosa among the articles was as follows: more than 72% of studies revealed >50% level of resistance to cefepime, followed by aztreonam (53.2%), ceftazidime (61%), piperacillin/tazobactam (54.5%), meropenem (48.3%), and imipenem (42.4%). The selection of empiric antipseudomonal antibiotics is absolutely uncertain and hazardous, and the risk of clinical failure may be more among cephalosporins and piperacillin-tazobactam as well as aztreonam. The results of this study illustrate that the methods enabling clinics to identify the bacterium resistance pattern and its genetic basis and to have the opportunity of empiric therapies through access to updated local data of antimicrobial susceptibility pattern are the most effective methods. However, the widespread usage of these approaches undoubtedly needs reliable molecular and nucleic acid-based devices, which are both affordable and available.

High prevalence of <i>bla_VEB</i>, <i>bla_GES</i> and <i>bla_PER</i> genes in beta-lactam resistant clinical isolates of <i>Pseudomonas aeruginosa</i>

“…Suitable drugs against infections caused by this bacterium are aminoglycosides, fluoroquinolones, selected β-lactams (e.g., ticarcillin, piperacillin, ceftazidime, aztreonam, and carbapenems), and a β-lactam/β-lactamase inhibitor compound [27] . Treating P. aeruginosa infections has become a major challenge due to the bacterium's ability to develop widespread antibiotic resistance [28] . One of the most prominent features of these bacteria is their resistance to clinically important antibiotics such as third-generation cephalosporins, imipenem, aztreonam, and other important beta-lactams [29] .…”

“…Acquired resistance to beta-lactams is due to the production of β-lactamase enzymes such as broad-spectrum beta-lactamases (ESBLs), Metallo-β-lactamases (MBLs), and sometimes AmpC plasmid β-lactamases [28] . Beta-lactamases are classified as A, B, C, and D groups by Ambler [12] while sequencing on class A β-lactamase indicated the presence of subclasses A1 and A2 with 100% similarity and highly conserved [30] .…”

Treatment of Patients with Community-Acquired Pneumonia: Official Practice Guideline of the Infectious Diseases and Tropical Medicine Research Center Advisory Committee

“…Among anti-pseudomonal/anti-pneumococcal beta-lactams, piperacillin-tazobactam, cefepime, ceftazidime, imipenem, and meropenem are available in Iran. But according to accomplished studies, the resistance rate seems high in all anti-pseudomonal regimens, particularly in cephalosporins (ceftazidime and cefepime) (28). The results of studies are heterogeneous, and data regarding pure community-acquired Pseudomonas are unavailable.…”

“…However, data reveal three main mechanisms of beta-lactam resistance: Extended-spectrum beta-lactamase (ESBL), Metallo β-lactamases (MBL), and plasmidic AmpC β-lactamases among Pseudomonas isolates in Iran. Among monobactams, we omitted aztreonam from CAP treatment due to data about the high antibiotic resistance rate and inaccessibility in Iran (28).…”