Molecular Mechanism of the β-Lactamase Mediated β-Lactam Antibiotic Resistance of Pseudomonas aeruginosa Isolated From a Chinese Teaching Hospital

Abstract

Pseudomonas aeruginosa can cause infections in the blood, lungs (pneumonia), or other parts of the body after surgery. To investigate the molecular characteristics of β-lactam antibiotic resistance of P. aeruginosa isolated from a hospital population between 2015 and 2017, in this study, the antimicrobial susceptibility and the resistance gene profile of the bacteria were determined. The Pulsed-field gel electrophoresis (PFGE) was used to characterize the clonal relatedness and sequencing and comparative genomic analysis were performed to analyze the structure of the resistance gene-related sequences. As a result, of the 260 P. aeruginosa strains analyzed, the resistance rates for 6 β-lactam antibiotics ranged from 4.6 to 9.6%. A total of 7 genotypes of 44 β-lactamase genes were identified in 23 isolates (8.9%, 23/260). Four transconjugants from different donors carrying blaCARB-3 exhibited a phenotype of reduced susceptibility to piperacillin–tazobactam, ceftazidime, and cefepime, and 2 transconjugants harboring blaIMP-45 exhibited a phenotype of reduced susceptibility to carbapenems. blaCARB positive isolates (n = 12) presented six PFGE patterns, designated groups A to F. Two bla genes (blaIMP-45 and blaOXA-1) in PA1609 related to a class 1 integron (intI1-blaIMP-45-blaOXA-1-aac(6′)-Ib7-catB3-qacE∆1-sul1) were encoded on a plasmid (pPA1609-475), while the blaCARB-3 gene of PA1616 also related to a class 1 integron was located on the chromosome. The results suggest that β-lactam antibiotic resistance and clonal dissemination exist in this hospital population. It indicates the necessity for molecular surveillance in tracking β-lactamase-producing strains and emphasizes the need for epidemiological monitoring.

The Prevalence of blaCTX-M, blaTEM Genes in Bacteria Isolated From Bladder Cancer Patients with UTI

“…The presence of bla TEM in K.pneumoniae isolates is in agreement with (65) they reported in a study conducted in Iran that bla TEM in K.pneumoniae isolates was about (12.4%), (66) reported the prevalence rates for bla TEM (12.35%), in urinary K. pneumonia strains ; (67)revealed that 16.1% of K.pneumoniae isolates produced bla TEM while higher percentage than our finding recorded by (68) about 83% . P.aeruginosae in our study produced bla TEM gene in accordance with a study conducted by (69) they reported that 15% of P.aeruginosae isolates were carry bla TEM gene ; (70) investigated that 26.7% of P.aeruginosae strains were have bla TEM ; (71) , revealed that 27.72% of P.aeruginosae isolates were harbored bla TEM gene ; while in a study conducted in Chinese teaching hospitals , (72) reported that very low percentage 4.5% of P.aeruginosae expressed bla TEM gene .…”

Genomic epidemiology and mechanisms of antibiotic resistance in Pseudomonas aeruginosa isolated from children’s hospital in Shenzhen, China

“…We report that bla CTX-M-15 is the predominant ESBL encoding gene present in P. aeruginosa and is highly disseminated in the reported '23' STs. Similar resistance encoding genes were reported globally including in China, but our study is in contrast with some reports in China [32,33,34,35]. No bla OXA-48 gene was reported in this study.…”

“…We have recorded high resistance for commonly used antimicrobials piperacillin-tazobactam (56%), cefepime (40%), ceftazidime (39%), imipenem (36%) and cipro oxacin (32%) respectively. P. aeruginosa strains show a similar resistance phenotype globally and in other provinces of China such as Zhejiang and rates of resistance are increasing rapidly which is particularly alarming in the healthcare sector [31,32]. In addition to this 42% ESBL producers were observed by VITEK ® 2 compact system (BioMerieux, France) and DDDM which is lower compared to Chinese data but is similar to other Asian countries such as Malaysia [33,34].…”

Phenotypic and genotypic discrepancies for carbapenemase-producing Citrobacter freundii in multiple isolates from a single patient

“…Genes are color-coded according to the following key: dark blue, transposase and integrase genes; red, antimicrobial resistance genes; dark red, mercury resistance genes; grey, tra gene complex; dark green, DNA metabolism; brown, plasmid maintenance and replication; white, all other genes the bla CARB-2 gene presented a different resistance profile from the other two, which included reduced susceptibility to ceftazidime, cefepime, aztreonam and piperacillintazobactam. Conjugation experiments performed on E. coli by Lin et al demonstrated that carriage of the closely related bla CARB-3 gene was associated with reduced susceptibility to piperacillin-tazobactam, ceftazidime, and cefepime [15]. The additional resistance genes found among our isolates were located in gene cassettes within class 1 integrons, demonstrating that C. freundii can acquire resistance genes from other organisms.…”