Detection of blaSPM-1 Metallo-β-Lactamase Gene in Imipenem-Resistant Pseudomonas aeruginosa Strains Isolated From Hospitalized Patients in Isfahan Hospitals

Abstract

Background: Pseudomonas aeruginosa is an opportunistic human pathogen, which causes serious problems especially in people who have immunodeficiency. Recently, metallo-β-lactamase (MBLs) resistance in this bacterium has led to some difficulties in treating bacterial infections. The blaSPM-1 is one of the MBL gene families, which induces resistance to the carbapenem class antibiotics; this gene has not been previously assessed in Iran. Objectives: Detection and quantification of blaSPM-1-metallo-β-lactamase gene among resistant Pseudomonas aeruginosa strains (imipenem), isolated from patients in Isfahan hospitals. Patients and Methods: A total of 180 samples were isolated from various nosocomial infections. These isolates were identified as Pseudomonas aeruginosa by using biochemical tests. In order to determine their bacterial drug resistance-pattern the Kirby-Bauer disk diffusion method was utilized. Presence of MBLs in imipenem isolates was detected using the combine disk technique (IMP-EDTA). Similarly, an E-test on Mueller-Hinton agar was used to determine the minimal inhibitory concentration (MIC) of imipenem isolates. The imipenem isolates were then subjected to polymerase chain reaction (PCR) to detect the blaSPM-1 gene. Data were analyzed using the SPSS software (version 16, SPSS Inc., Chicago, IL, USA). Results: In total, 96 isolates of Pseudomonas aeruginosa were collected. Of all isolates, 34 (35.41%) were found to be imipenem-resistant P. aeruginosa. The MIC levels in all imipenem-resistant strains were MIC ≥ 32 μg/mL. Thirteen (38.23%) of the imipenem-resistant P. aeruginosa isolates were MBL positive. None of the isolates carried the blaSPM-1 gene, as indicated by the PCR assay. Conclusions: The rate of imipenem resistance due to MBL has increased dramatically. Early detection and infection-control practices are the best antimicrobial strategy for this organism.

Phenotypic detection of extended spectrum -lactamase and Metallo -lactamase production by Gram negative uropathogens after exposure to gamma radiation

“…Lucena et al (2014) concluded that MBL producing strains of P. aeuroginosa (clinical isolates) were 49% resistant for ATM, while Abd El-Baky et al (2013) showed that, MBL-producing P. aeurginosa of clinical isolates were 90.3% resistant for ATM. Sedighi et al (2015) showed that MBL-producing strains of P. aeuroginosa isolated from hospitalized patients were 100% resistant against cefepime and this is accordance with the obtained data in this study. Lucena et al (2014) showed that 93 MBL-producing clinical isolates of P. aeuroginosa were 100% resistant to ciprofloxacin and gentamicin.…”

CLSI based antibiogram profile and the detection of MDR and XDR strains of Acinetobacter baumannii isolated from urine samples

“…The categorization of MDR and XDR in the present study was done as per standard interim protocols as done in earlier studies (46). A. baumannii is considered as MDR-Ab when it exhibits resistance to at least three different classes of antimicrobial agents mainly beta-lactams (third-generation cephalosporins), aminoglycosides, fluoroquinolones and more recently carbapenems (47)(48)(49). In correlation with this, it was not infrequent in the present investigation 71.23% of the isolates showing multidrug resistance to more than three antimicrobial categories.…”

Molecular detection of β-lactamase and integron genes in clinical strains of Klebsiella pneumoniae by multiplex polymerase chain reaction

“…Unfortunately, the incidence of β-lactamase-producing K. pneumoniae is on the rise 15 . The detection of different β-lactamase genes in resistant bacteria and characterization of their antimicrobial susceptibility profiles could provide important data regarding high risk factors and infection epidemiology [16][17][18] . To date, only a few studies have investigated the types of β-lactamase-producing Enterobacteriaceae and strains possessing integrons present in Iranian hospitals 19,20 .…”