Detection of Metallo-Beta Lactamases Among Carbapenem-Resistant Pseudomonas aeruginosa

Abstract

Background:Carbapenems are important drugs used for the treatment of Pseudomonas aeruginosa infections, however metallo-β-lactamases (MBL) are able to efficiently hydrolyze these classes of drugs. Immediate detection of the MBL-producing P. aeruginosa is necessary in order to accurately treat infections caused by this organism.Objectives:To determine the prevalence of MBL producing P. aeruginosa in burn and non-burn patients by two phenotypic tests and polymerase chain reaction (PCR) and to compare phenotypic tests with PCR.Materials and Methods:A total of 223 non-duplicate strains of P. aeruginosa were collected from three teaching hospitals of Ahvaz, Iran. Antimicrobial susceptibility and minimum inhibitory concentrations (MICs) of carbapenems (imipenem, meropenem, doripenem and ertapenem) were determined by the Kirby-Bauer and E-test methods. Combined disk (CD) test, MBL E-test and PCR were performed for carbapenem-resistant P. aeruginosa isolates.Results:Amongst all the P. aeruginosa isolates, 58.7% were resistant to imipenem while 31.8%, 13.5% and 74.4% were resistant to meropenem, doripenem and ertapenem, respectively. Amongst all the P. aeruginosa isolates, 44.4% were multidrug resistant and 13.45% were resistant to all of the carbapenems. The CD test with doripenem disk / 750 μg ethylene diamine tetra acetic acid (EDTA) had the highest efficiency compared to the other phenotypic tests. blaIMP and blaVIM genes were detected in 11.7% and 0.4% of isolates, respectively. blaSPM and blaNDM genes were not observed.Conclusions:Epidemiological and regional evaluation of MBL-producing P. aeruginosa through simple and inexpensive methods should be considered for effective treatment of carbapenem-resistant P. aeruginosa infections.

Evaluation of Metallo-β-Lactamase-Production and Carriage of bla-VIM Genes in Pseudomonas aeruginosa Isolated from Burn Wound Infections in Isfahan

“…In Kurdistan and Ahwaz 22% and 19.5% of P. aeruginosa isolates among burn patients were identified as MBL-producing isolates (3). In a study conducted by Farajzadeh Sheikh et al (15) in Ahwaz among P. aeruginosa isolates in burn and non-burn patients, all of the imipenem-resistant isolates were MBL E-test positive, which correlates with our results, although it would be better if the MBL-production among our imipenem resistant P. aeruginosa isolates were confirmed by an MBL E-test as well. The EDTA-IMP DDST test and sodium mercaptoacetic acid (SMA)-IMP DDST revealed that 98.1% of imipenem-resistant P. aeruginosa and 78.9% of P. aeruginosa isolates were positive for production of metallo-β-lactamase enzymes in Brazil and Japan, respectively (8, 14).…”

“…This study revealed that the resistance rates to imipenem and meropenem were very high (96%). Farajzadeh Sheikh et al (15) reported an imipenem resistance rate of 58.7% among P. aeruginosa isolates in Ahwaz, which was lower than our resistance rate. However, Anvarinejad and colleagues’ (1) study, also conducted in Ahwaz, was in agreement with our study: 98.1% of MBL-producing P. aeruginosa strains, which were isolated from hospitalized patients in a burn unit showed resistance to imipenem.…”

“…Severe antimicrobial resistance in this bacterium has complicated the treatment of infections caused by drug-resistant P. aeruginosa strains among burn patients (15). Recently, the increase of carbapenem resistance in P. aeruginosa has been documented all over the world due to metallo-β-lactamase production, including the VIM type (16).…”

Detection Rate of Metallo-β-Lactamase-Expressing Genes; blaVIM-1, blaVIM-2 and blaSPM-1 in Pseudomonas aeruginosa Isolates

“…Imipenem and meropenem are commonly used antibiotics for the treatment of hospital-acquired infec tions; nevertheless, enhanced resistance against these agents has restricted their success. 17 In our results, among 28 imipenem-resistant strains, 17 (60.7%) were positive for production of MBL as shown by DDST. Kalantar et al 18 exhibited that 22% of the imipenem-resistant P. aerugi nosa isolates were MBL-positive and 8 strains (8%) were positive for blaVIM1 as proved by PCR.…”

Systematic review and meta-analysis of imipenem-resistant Pseudomonas aeruginosa prevalence in Iran

“…Finally, after applying the exclusion criteria 37 articles with full-texts describing the prevalence of imipenem-resistant P. aeruginosa were selected for systematic review and meta-analysis (Table 1). Most of the studies were performed in Tehran (16), and Isfahan (5), followed by Ahvaz (3), Hamedan (2), Kermanshah (2), Zanjan (2), Urmia (2), Arak (1), Gillan (1), Mashhad (1), Tabriz (1), and Zahedan (1). The highest and lowest prevalence rates of IRPA were seen in Tehran (97.5%) and Hamedan (7.5%) provinces.…”