Carbapenemase Gene Dynamics in CREC During COVID-19 in Guang

2026-04-12

Carbapenemase Gene Dynamics in CREC During COVID-19 in Guangdong

Study Background and Research Question

The global threat posed by carbapenem-resistant Enterobacteriaceae (CRE) has intensified in recent years, with Enterobacter cloacae (CREC) emerging as a critical contributor to hospital-acquired infections, especially in China. The COVID-19 pandemic further complicated the landscape, as increased antibiotic use and healthcare system pressures may have accelerated the emergence and spread of multidrug-resistant pathogens. Despite this context, detailed investigations into the molecular characteristics and transmission dynamics of carbapenemase-encoding genes (CEGs) in CREC during the pandemic have remained scarce. Addressing this gap, Chen et al. (2025) aimed to dissect the prevalence, genetic distribution, and mobility of CEGs among CREC isolates from eight teaching hospitals in Guangdong province, China, spanning December 2022 to June 2024 ([source_type: paper][source_link: https://doi.org/10.1186/s12866-025-04300-0]).

Key Innovation from the Reference Study

The principal innovation of the study lies in its comprehensive, multicenter genomic and epidemiological analysis of CREC during a period of heightened clinical complexity. By systematically identifying both the chromosomal and plasmid locations of major CEGs—including blaNDM−1, blaIMP, and blaKPC−2—the authors provide direct evidence of the dominant role of plasmid-mediated horizontal gene transfer in resistance propagation. The work further quantifies the success rates of gene transmission and links these molecular findings to specific clinical and demographic factors, such as higher detection in elderly male patients and respiratory medicine wards ([source_type: paper][source_link: https://doi.org/10.1186/s12866-025-04300-0]).

Methods and Experimental Design Insights

Chen et al. collected 54 non-redundant CREC isolates from eight tertiary hospitals. The study utilized a variable temperature sodium dodecyl sulfate (SDS) plasmid elimination method alongside PCR assays to localize CEGs to chromosomal or plasmid DNA. Broth microdilution determined antibiotic susceptibility, and conjugation experiments assessed horizontal transfer potential. Mobile genetic elements (MGEs) were characterized, and genotyping was performed with ERIC-PCR, analyzed via NTSYS software for clonal diversity ([source_type: paper][source_link: https://doi.org/10.1186/s12866-025-04300-0]).

Protocol Parameters

assay | variable temperature SDS plasmid elimination | used to distinguish plasmid vs. chromosomal CEG location | enables targeted tracking of resistance gene mobility | paper ([source_link: https://doi.org/10.1186/s12866-025-04300-0])
assay | PCR detection of blaNDM−1, blaIMP, blaKPC−2 | 100% specificity in this cohort | confirms gene presence and localization | paper ([source_link: https://doi.org/10.1186/s12866-025-04300-0])
assay | broth microdilution | MIC determination for imipenem and others | standard for resistance assessment | paper ([source_link: https://doi.org/10.1186/s12866-025-04300-0])
assay | conjugation experiment | 95.65% CEG transfer success | measures horizontal gene transfer efficiency | paper ([source_link: https://doi.org/10.1186/s12866-025-04300-0])
workflow | use of reference strains and ERIC-PCR for genotyping | applicable for epidemiological tracing | enables detection of clonal spread | workflow_recommendation

Core Findings and Why They Matter

Among the 54 CREC isolates, 85.19% harbored carbapenemase-encoding genes ([source_type: paper][source_link: https://doi.org/10.1186/s12866-025-04300-0]). Specifically, 33.33% had blaNDM−1 on both chromosomes and plasmids, while 46.30% carried blaNDM−1 exclusively on plasmids, highlighting the gene's prominence in regional resistance. Plasmid transfer experiments demonstrated a high (95.65%) horizontal transfer rate of CEGs, with blaNDM−1 and blaIMP showing near-complete transferability ([source_type: paper][source_link: https://doi.org/10.1186/s12866-025-04300-0]). The clinical significance is underscored by the multidrug resistance patterns observed: CEG-positive isolates exhibited significantly higher resistance rates to imipenem, cefepime, gentamicin, ceftazidime/avibactam, ciprofloxacin, and levofloxacin compared to CEG-negative strains ([source_type: paper][source_link: https://doi.org/10.1186/s12866-025-04300-0]). Mobile genetic elements, especially ISEcp1, were highly prevalent, facilitating gene dissemination. Epidemiologically, higher detection rates occurred among men, the elderly, respiratory medicine patients, and sputum samples, suggesting targeted surveillance may be warranted.

Comparison with Existing Internal Articles

A review of recent literature, including articles such as "Imipenem in Translational Antibacterial Research: Mechanisms and Modeling" ([source_link: https://meropenemtrihydrate.com/index.php?g=Wap&m=Article&a=detail&id=11069]) and "Imipenem in Advanced Antibiotic Resistance and Immune Modulation" ([source_link: https://er-mscarlet.com/index.php?g=Wap&m=Article&a=detail&id=10939]), reveals a strong alignment with Chen et al.'s core findings. These internal resources discuss the mechanistic action of imipenem—a semisynthetic thienamycin antibiotic—and its pivotal role in translational resistance research, notably in the context of multidrug resistance and immune response modulation. However, the reference study uniquely quantifies real-world plasmid- and chromosome-based gene carriage and horizontal transfer rates during a pandemic surge, bridging experimental and epidemiological insights. The work further reinforces the urgent need for robust sepsis animal models and resistance tracking, as discussed in the internal reviews, and highlights the translational implications for antibacterial research workflows.

Limitations and Transferability

While this study offers rich molecular and epidemiological data, limitations include its regional focus on Guangdong province and the relatively small sample size (54 isolates). The pandemic context may have introduced unique selective pressures not generalizable to non-pandemic settings. Additionally, while transmission dynamics are robustly characterized, the clinical outcome data for patients with CEG-positive CREC were not detailed, limiting direct translational conclusions for therapeutic strategies. Nonetheless, the core findings are broadly applicable to hospital-based resistance surveillance and inform the design of future antibacterial research, including resistance modeling and sepsis workflows ([source_type: paper][source_link: https://doi.org/10.1186/s12866-025-04300-0]).

Research Support Resources

Researchers aiming to replicate or extend these studies in antibacterial research, resistance mechanism mapping, or sepsis animal model development may require high-quality reference compounds. Imipenem (SKU P10075, APExBIO) is a well-characterized semisynthetic thienamycin antibiotic suitable for in vitro and in vivo workflows, including those assessing resistance phenotypes in gram-negative and gram-positive bacteria or immune response modulation ([source_type: product_spec][source_link: https://www.apexbt.com/imipenem.html]). For further context on Imipenem’s mechanistic and translational research applications, see the reviews at meropenemtrihydrate.com and er-mscarlet.com.