Role of the Outer Membrane Protein OprD2 in Carbapenem-Resistance Mechanisms of Pseudomonas aeruginosa

Abstract

We investigated the relationship between the outer membrane protein OprD2 and carbapenem-resistance in 141 clinical isolates of Pseudomonas aeruginosa collected between January and December 2013 from the First Affiliated Hospital of Anhui Medical University in China. Agar dilution methods were employed to determine the minimum inhibitory concentration of meropenem (MEM) and imipenem (IMP) for P. aeruginosa. The gene encoding OprD2 was amplified from141 P. aeruginosa isolates and analyzed by PCR and DNA sequencing. Differences between the effects of IMPR and IMPS groups on the resistance of the P. aeruginosa were observed by SDS-poly acrylamide gel electrophoresis (SDS-PAGE). Three resistance types were classified in the 141 carbapenem-resistant P. aeruginosa (CRPA) isolates tested, namely IMPRMEMR (66.7%), IMPRMEMS (32.6%), and IMPRMEMS (0.7%). DNA sequencing revealed significant diverse gene mutations in the OprD2-encoding gene in these strains. Thirty-four strains had large fragment deletions in the OprD2gene, in 6 strains the gene contained fragment inserts, and in 96 resistant strains, the gene featured small fragment deletions or multi-site mutations. Only 4 metallo-β-lactamase strains and 1 imipenem-sensitive (meropenem-resistant) strain showed a normal OprD2 gene. Using SDS-PAGE to detect the outer membrane protein in 16 CRPA isolates, it was found that 10 IMPRMEMR strains and 5 IMPRMEMS strains had lost the OprD2 protein, while the IMPSMEMR strain contained a normal 46-kDa protein. In conclusion, mutation or loss of the OprD2-encoding gene caused the loss of OprD2, which further led to carbapenem-resistance of P. aeruginosa. Our findings provide insights into the mechanism of carbapenem resistance in P. aeruginosa.

Prevalence of Pseudomonas aeruginosa and antimicrobial-resistant Pseudomonas aeruginosa in patients with pneumonia in mainland China: a systematic review and meta-analysis

“…Previous studies indicated that carbapenem resistance in Chinese P. aeruginosa isolates was driven mainly by a deficiency of OprD and may or may not be accompanied by the overexpression of MexAB-OprM or metallo-lactamase (MBL) production. 56,57 Although relatively uncommon among CRPA in China, with a proportion of 8.5%…”

Upstream Region of OprD Mutations in Imipenem-Resistant and Imipenem-Sensitive Pseudomonas Aeruginosa Isolates

“…In a study performed by Aki Hirabayashi et al (24). There was a direct relationship between the alteration or loss of oprD and the increase in MIC, for imipenem but not meropenem and other carbapenems (3,9,11). In a study conducted by Yumiko Sanbongi et al (25).…”

“…PCR and sequence analysis revealed an interpolation of a large fragment in the oprD gene were known as IS elements that are not observed in this study. Jilu Shen et al (9). Reported 96.5% (136/141) of the resistant isolates showed deletions or multi mutations that were driven loss or insertion of the oprD-encoding gene, 34 strains had a large deletion in the OprD gene, 6 isolates had IS, and 4 strains had no mutation and showed a normal OprD2 gene.…”

“…This mechanism causes blocking of the entrance of carbapenems particularly imipenem into a bacterium (8,9). OprD-mediated resistance occurs as a result of decreased transcriptional expression of oprD and/or loss of function mutations that disrupt protein activity.…”

Study on the resistance mechanism via outer membrane protein OprD2 and metal β-lactamase expression in the cell wall of Pseudomonas aeruginosa

“…Additionally, OprD2 protein is able to form a specific locus by binding bacteria and carbapenems. It is one and only porin that allows antibiotics go through smoothly in current studies, especially for Pseudomonas aeruginosa (9). Therefore, loss or reduction in OMP OprD2 expression is an important mechanism leading to Pseudomonas aeruginosa resistance to carbapenem antibiotics.…”