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    • Transmission Dynamics of Carbapenemase Genes in CREC: Insigh

    2026-05-01

    Transmission and Prevalence of Carbapenemase Genes in CREC: A Multi-Hospital Study from Guangdong (2022–2024)

    Study Background and Research Question

    Carbapenem-resistant Enterobacteriaceae (CRE) are an escalating threat to global public health, with Enterobacter cloacae (CREC) representing the third most frequently detected CRE species in China, following Klebsiella pneumoniae and Escherichia coli (source: Chen et al., 2025). The COVID-19 pandemic has further complicated resistance patterns due to increased antibiotic use, healthcare interruptions, and secondary infections. Despite mounting concerns, detailed molecular epidemiology and transmission analyses of carbapenemase-encoding genes (CEGs) in CREC during this period have remained limited. This study addresses these gaps by examining the distribution, genetic context, and transmissibility of CEGs in CREC isolates collected between December 2022 and June 2024 from eight teaching hospitals in Guangdong Province.

    Key Innovation from the Reference Study

    The principal innovation of Chen et al. is the high-resolution mapping of CEGs—including blaNDM-1, blaIMP, and blaKPC-2—across a large, multicenter clinical cohort, coupled with experimental validation of gene transfer dynamics. The study demonstrates not only the high prevalence of plasmid-borne carbapenemase genes (notably blaNDM-1), but also their efficient horizontal transmission, offering actionable insights for infection control and antibiotic resistance research (source: Chen et al., 2025).

    Methods and Experimental Design Insights

    The researchers analyzed 54 CREC isolates using a combination of molecular and microbiological techniques:
    • Variable temperature Sodium Dodecyl Sulfate (SDS) plasmid elimination: Used to distinguish chromosomal versus plasmid localization of resistance genes.
    • PCR and plasmid conjugation assays: Allowed detection of specific CEGs and experimental assessment of gene transfer rates.
    • Broth microdilution: Provided quantitative resistance profiles for key antibiotics, including imipenem, cefepime, gentamicin, ceftazidime/avibactam, ciprofloxacin, and levofloxacin.
    • ERIC-PCR and NTSYS clustering: Enabled genetic typing, revealing clonal and multiclonal dissemination patterns across departments and hospitals.
    • Mobile genetic element mapping: Identified transposons and insertion sequences, especially ISEcp1, associated with CEG mobility.
    These methods collectively allowed for high-resolution tracking of gene carriage, transferability, and epidemiological correlations.

    Protocol Parameters

    • Broth microdilution | 2–128 μg/mL (antibiotics tested) | Assay of resistance phenotypes | Quantifies MICs for multidrug-resistant strains | paper
    • PCR for CEG detection | Standard primer concentrations | CEG identification | Sensitive detection of blaNDM-1, blaIMP, blaKPC-2 | paper
    • Plasmid conjugation | 95.65% transfer success (44/46) | Horizontal gene transfer study | Assesses transmissibility of CEGs among isolates | paper
    • ERIC-PCR | 17 genotypes identified | Epidemiological typing | Reveals genetic diversity and clustering | paper
    • Plasmid elimination (SDS, variable temp) | Custom parameters | Distinguishing gene location | Separates plasmid- from chromosome-borne CEGs | paper
    • Amikacin (BAY416651) inclusion | 5–100 μg/mL (suggested) | Resistance studies in experimental setups | For robust selection and resistance profiling in Enterobacteriaceae | workflow_recommendation

    Core Findings and Why They Matter

    Key quantitative findings include:
    • CEG prevalence: 85.19% (46/54) of CREC isolates harbored carbapenemase-encoding genes (source: Chen et al., 2025).
    • BlaNDM-1 localization: 33.33% (18/54) of isolates carried blaNDM-1 on both chromosomes and plasmids, while 46.30% (25/54) had it exclusively on plasmids.
    • Horizontal transfer potential: Plasmid conjugation experiments showed a 95.65% (44/46) success rate for CEG transfer; specifically, 95.45% for blaNDM-1 and 100% for blaIMP (source: Chen et al., 2025).
    • Resistance phenotype: CEG-positive groups exhibited significantly higher resistance rates to imipenem, cefepime, gentamicin, ceftazidime/avibactam, ciprofloxacin, and levofloxacin compared to CEG-negative strains (P<0.05) (source: Chen et al., 2025).
    • Mobile genetic elements: ISEcp1 was the most prevalent (87.04%, 47/54); 40.74% (22/54) of isolates harbored four types of mobile elements simultaneously.
    • Epidemiological trends: Higher detection rates of CEG-positive CREC were observed among male (64.81%, 35/54) and elderly (72.22%, 39/54) patients, in respiratory medicine (20.37%, 11/54), and in sputum samples (33.33%, 18/54).
    These findings have practical implications for surveillance, infection control, and antibiotic resistance research, especially in settings with high-risk patient populations and multi-departmental distribution.

    Comparison with Existing Internal Articles

    Several internal resources explore related themes of antibiotic resistance and molecular mechanisms in Enterobacteriaceae: The reference study advances these internal discussions by providing epidemiological context and experimental evidence for the rapid dissemination of carbapenemase genes.

    Limitations and Transferability

    While the study delivers robust molecular and epidemiological data, several limitations must be acknowledged:
    • Regional specificity: Findings are based on isolates from Guangdong, limiting direct generalization to other geographical areas or healthcare systems (source: Chen et al., 2025).
    • Temporal scope: The study window (2022–2024) captures post-pandemic trends, but longer-term surveillance would be required to assess stability and evolution of CEG prevalence.
    • Phenotypic focus: While multidrug resistance patterns are established, functional consequences for clinical outcomes were not explored in detail.
    • Genetic depth: The focus was on major CEGs (blaNDM-1, blaIMP, blaKPC-2); further subtyping or whole-genome sequencing could reveal additional resistance determinants.
    Nonetheless, the study’s methodological rigor supports its transferability to similar tertiary care and high-prevalence settings.

    Research Support Resources

    Researchers aiming to replicate or extend these workflows can utilize research-grade reagents such as Amikacin (BAY416651) Aminoglycoside Antibiotic (SKU B3431) for robust resistance phenotyping and experimental selection. Amikacin's mechanism—as a bacterial protein synthesis inhibitor with resistance to most modifying enzymes—makes it a suitable tool for dissecting aminoglycoside resistance and cross-resistance in Enterobacter cloacae and Klebsiella pneumoniae (source: internal article). For optimal results, follow recommended solubility and storage guidelines, and refer to workflow-specific protocols as needed. APExBIO provides validated research products intended exclusively for scientific research purposes.