Infection and Drug Resistance最新文献

Backgroud: To investigate the molecular epidemiology of intestinal colonization by carbapenem-resistant Enterobacteriaceae (CRE) and identify risk factors for subsequent infection, providing evidence for early risk stratification and targeted prevention.

Methods: From August 2023 to August 2024, we retrospectively enrolled CRE-positive patients identified through active rectal swab screening at the First Affiliated Hospital of Kunming Medical University and monitored them for subsequent infections. Colonizing and infecting isolates were collected and tested for carbapenem-resistance genes, major virulence genes, capsular serotypes, and were subjected to multilocus sequence typing (MLST). Clinical data were integrated and multivariate logistic regression was performed to identify risk factors associated with secondary infections.

Results: Among 8,088 patients who underwent active intestinal CRE screening, the positivity rate was 0.53% (43/8,088). Among patients with colonization, the incidence of secondary infection was 37.2% (16/43). All patients with secondary infections were colonized and infected with Klebsiella pneumoniae, with the lower respiratory tract, bloodstream, and urinary tract being the primary infection sites. Multivariable analysis showed that having more than three comorbidities was an independent risk factor for hospital-acquired infection among colonized patients (odds ratio [OR]=0.118; 95% CI:0.017-0.812; P=0.030). The carriage rate of bla _KPC was 77.8% among colonizing strains and 100% among infecting strains. Among virulence genes, aerobactin, allS, and peg344 were significantly more prevalent in infecting strains (P<0.05). Homology analysis revealed that, except for one patient, the colonizing and infecting isolates in patients with secondary infections were highly homologous ST11-KL64, KPC-producing K. pneumoniae.

Conclusion: Although the intestinal colonization rate of CRE was relatively low, the risk of secondary infection remained substantial. Bacterial genetic traits and host conditions contribute to secondary infections. Establishing surveillance systems based on clinical and molecular epidemiology coupled with intensified screening in high-risk departments may help identify high-risk patients early and enable proactive interventions to reduce CRE-related secondary infections.

Purpose: With the advancement of metagenomic next-generation sequencing (mNGS), its role in diagnosing lower respiratory tract infections (LRTIs) has expanded rapidly. LRTIs remain a major global health burden, particularly in critically ill patients where diagnosis is challenging. Routine microbiological testing (RMT), including culture, microscopy, antigen detection, and PCR-are limited by low sensitivity, long turnaround times, and restricted pathogen coverage. This study assesses the diagnostic performance of mNGS in LRTIs, with emphasis on pathogen detection and resistance gene prediction, and compares it with traditional methods to clarify its clinical benefits and limitations.

Methods: This retrospective study included 367 hospitalized patients with suspected LRTIs. All patients underwent mNGS testing, which was compared with traditional diagnostic methods. We also used mNGS to explore the pathogen spectrum characteristics in critically ill patients with pneumonia and evaluated its applicability in predicting antimicrobial resistance genes and adjusting antibiotic treatment.

Results: For patients diagnosed with LRTIs, mNGS demonstrated superior microbial detection efficacy, particularly for bacteria and fungi, relative to culture (bacteria: 56.58% vs 17.37%, P < 0.0001; fungi: 49.65% vs 16.78%, P < 0.0001) and PCR (65.14% vs 45.14%, P < 0.05). In contrast to the non-severe pneumonia group, the detection rate of Enterococcus faecium was highest in the severe pneumonia group (P < 0.001), and the severe pneumonia group had more mixed infections (P < 0.001). In addition, mNGS showed high accuracy in predicting antibiotic resistance genes, with 90.57% agreement with antibiotic susceptibility testing (AST) results. Based on the mNGS results, 97.82% of patients underwent active adjustment to their antibiotic treatment regimen.

Conclusion: mNGS is an effective tool for diagnosing LRTIs, with significantly higher pathogen detection rates than traditional methods. mNGS also demonstrates high accuracy in predicting antimicrobial resistance, providing crucial support for clinical treatment decisions.

Background: Talaromycosis is increasingly recognized in immunocompromised individuals beyond those with HIV, including patients with primary immunodeficiencies such as Hyper-IgE syndrome (HIES). However, diagnosing disseminated infection remains challenging due to nonspecific clinical manifestations and limitations of conventional diagnostic methods.

Case presentation: We report a rare case of recurrent disseminated Talaromyces marneffei (T. marneffei) infection in a 25-year-old male with STAT3-mutated HIES. Initially presenting with abnormal liver function tests, the patient had a history of T. marneffei pulmonary infection successfully treated with itraconazole. During the current admission, he developed intermittent fever, jaundice, and splenomegaly. Initial evaluations led to a misdiagnosis of chronic drug-induced liver injury (DILI). Subsequent fever recurrence and worsening liver function prompted further investigation. Metagenomic next-generation sequencing (mNGS) and histopathology of liver revealed T. marneffei, confirming disseminated infection involving the liver. Histopathological examination of the liver showed granulomatous inflammation with IgG4-positive plasma cell infiltration, further complicating the differential diagnosis. The patient responded well to intravenous voriconazole, with significant improvement in liver function and radiological findings.

Conclusion: Disseminated talaromycosis should be considered in immunocompromised patients presenting with unexplained fever, hepatosplenomegaly, or organ dysfunction, even in the absence of classic symptoms. Integration of mNGS into diagnostic workflows enhances pathogen detection, and long-term antifungal prophylaxis may be necessary in patients with persistent immune deficiencies.

Background: Cardiovascular disease represents the leading cause of mortality among tuberculosis (TB) patients. Both patients with tuberculosis or coronary artery disease (CAD) commonly exhibit lipid metabolism disorders. This study aims to identify specific lipids to enable early diagnosis of tuberculosis-coronary artery disease comorbidity (TB-CAD).

Methods: Blood samples were collected from hospitalized patients with TB, TB-CAD, or CAD, as well as normal healthy controls (NC), at the affiliated Changsha Central Hospital of University of South China between April 2024 and February 2025. A broad-targeted lipidomics approach based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to identify differential lipids.

Results: The K-Means analysis showed sphingolipid, glycerolipid, and glycerophospholipid levels were decreased in patients with TB-CAD. A total of 49 differential lipids were identified to distinguish TB-CAD from the other groups. The results of receiver operating characteristic curve analysis revealed three lipids such as CE(20:0), PC(14:0_20:4) and CE(18:0) as potential biomarkers for early diagnosis of TB-CAD. The integrated diagnostic model comprising these three lipids demonstrated favorable performance, achieving AUC, sensitivity, and specificity values of 0.834, 0.900, and 0.622, respectively. KEGG analysis showed the metabolism of linoleic acid, alpha-linolenic acid, and arachidonic acid were considered pathways related to tuberculosis-coronary artery disease comorbidity.

Conclusion: This study not only identified potential biomarkers for TB-CAD diagnosis but also provided a foundation for in-depth exploration of the pathogenesis underlying tuberculosis-coronary artery disease comorbidity.

Background: Inappropriate antibiotic use drives antimicrobial resistance (AMR). Performing pathogen detection before initiating antimicrobial therapy is essential for antimicrobial stewardship (AMS), enabling targeted treatment. Robust evidence on multifaceted interventions' sustained impact on pre-therapy pathogen detection specimen submission rates, AMS metrics, and multidrug-resistant organisms (MDROs) is limited.

Methods: Interrupted time series analysis evaluated a comprehensive AMS intervention (April 2023) at a tertiary care hospital in China (April 2022-May 2025). Interventions included: team establishment, lab expansion, education, electronic restrictions for restricted/special use-levels antibiotics (mandating pre-therapy pathogen detection specimen submission rate), audit/feedback, and monitoring. Segmented regression assessed level (immediate) and slope (trend) changes in pre-therapy pathogen detection specimen submission rate, antimicrobial use, costs, and MDRO isolate rates.

Results: Post-intervention, overall pre-therapy pathogen detection specimen submission rate increased immediately (+9.82%, P=0.009) with sustained monthly growth (+1.21%, P<0.001); increases occurred across all antimicrobial classes (all P<0.05). Antimicrobial use intensity reversed significantly from a pre-intervention upward trend (β₁ = +1.22 DDDs/100PD, P=0.002) to a sustained downward trajectory (β₃ = -1.36, P=0.001), with non-restricted agents showing the steepest decline (net slope = -0.16). Concurrently, antimicrobial utilization rate, per capita costs, and cost proportion reversed to downward trends (all P<0.05), while testing costs remained stable Only carbapenem-resistant Klebsiella pneumoniae (CRKP) exhibited sustained reduction (-0.87%/month, P=0.013); other MDROs showed no significant changes.

Conclusion: The intervention significantly improved pre-therapy pathogen detection specimen submission rate and optimized antimicrobial use (reduced intensity/costs), but demonstrated limited resistance impact beyond CRKP reduction. Sustainable AMR control requires integrating diagnostic stewardship with infection prevention programs.

Purpose: To systematically analyse and identify volatile organic compounds (VOCs) released by clinical Klebsiella pneumoniae (K. pneumoniae) during growth via proton transfer reaction-mass spectrometry (PTR-MS), aiming to establish a rapid and accurate method for differentiating and identifying carbapenem-resistant Klebsiella pneumoniae (CRKP) and KPC and NDM producers.

Methods: Nonrepetitive clinical strains isolated from patient specimens were collected from September 2021 to May 2025. The strains were subjected to drug susceptibility testing and carbapenemase genotype identification via the VITEK2 system and polymerase chain reaction (PCR). The clinical strains were incubated in a closed system under the combined pressure of meropenem (MEM) and carbapenemase inhibitors for 3 h. PTR-MS was used to monitor the inhibition rate of the characteristic VOC ion signal intensity to obtain drug susceptibility information of KP and carbapenemase type. Characteristic ions were characterized via fast gas chromatography (FGC)-PTR-MS.

Results: A total of 105 clinical isolates, including 53 carbapenem-susceptible Klebsiella pneumoniae (CSKP) isolates and 52 CRKP (43 KPC-positive and 9 NDM-positive) isolates, were collected. With MEM, the sensitivity and specificity of PTR-MS for monitoring CRKP were 98.08% and 100.00%, respectively. In the case of MEM combined with different carbapenemase inhibitors, the assay was evaluated using a subset of isolates (n=31), comprising 22 KPC-positive and 9 NDM-positive strains. The sensitivity and specificity of PTR-MS for monitoring single KPC producers were 90.91% and 100.00%, respectively, and those for single NDM producers were 88.89% and 100.00%, respectively (kappa= 0.853 and 0.919 for KPC- and NDM-positive strains, respectively). FGC-PTR-MS analysis indicated that the VOCs corresponding to these characteristic ions were acetaldehyde, ethanol and acetic acid.

Conclusion: Real-time monitoring by PTR-MS of the dynamic release characteristics of specific VOC ions in the headspace of CRKP within 3 h under the combined stress of antibiotics and carbapenemase inhibitors can provide important information for rapidly identifying CRKP and the main clinical carbapenemase types.

Purpose: HIV drug resistance is increasing globally, especially in resource-limited settings. NNRTIs, commonly used as first-line ART, have a low genetic barrier and are prone to resistance mutations. Lifelong ART contributes to the accumulation of drug resistance mutations (DRMs), compromising treatment efficacy. Genotypic resistance testing is essential before initiating or modifying ART. However, the Sanger sequencing method relies on successful PCR amplification, which is often suboptimal in low viral load (VL) samples, limiting sensitivity and coverage.

Patients and methods: We developed an optimized primer system targeting conserved regions in the protease (PR), reverse transcriptase (RT), and integrase (IN) genes, covering PR aa 1-99, RT aa 1-410 (including NNRTI resistance sites Y318 and N348), and IN aa 1-288. A total of 2,071 HIV-positive plasma samples collected in China (Jan 2023-Dec 2024) were analyzed using a PCR-Sanger sequencing method. Subtyping was performed using BLAST, COMET 2.4, and the HIV-1 Gene Sequences Database (China). Amplification success rates and mutation detection were evaluated across VL levels.

Results: The overall amplification success rates were 87.40% (1,810/2,071) for the PR/RT region and 87.06% (1,803/2,071) for the IN region. In samples with VLs of 50-200 copies/mL, the success rates remained above 80% for PR/RT and 78.10% for IN. For samples with VL ≥1000 copies/mL, both regions achieved amplification rates above 99%. Among eight samples harboring Y318 or N348 mutations, all were successfully amplified at 1000, 400, 200, and 100 copies/mL. Three of them consistently yielded detectable mutations across all gradients. Subtyping revealed CRF01_AE and CRF07_BC as the predominant strains, consistent with national epidemiological trends.

Conclusion: The optimized system improves amplification sensitivity and mutation coverage, especially in low-VL samples. It enables stable detection of key NNRTI resistance mutations and shows strong subtype compatibility, supporting its utility in clinical resistance surveillance and early detection.

Objective: To establish a predictive model for wound infection after ileostomy for rectal cancer and its relationship with nucleotide-binding oligomerisation domain-like receptor thermal protein domain-associated protein 3 (NLRP3) gene polymorphism.

Methods: A total of 347 samples were randomly divided into two groups: the model group (n = 260) and the verification group (n = 87). The patients in the model group were further divided into the infection group (n = 96) and the non-infection group (n = 164). Multivariate logistic regression was used to analyse the influencing factors of postoperative infection. The TaqMan probe method was used for genotyping.

Results: The results of multivariate logistic regression analysis showed that age >65 years, diabetes, operation time >105 minutes, loop colostomy and abnormal transepidermal water loss (TEWL) were independent risk factors. The risk value of postoperative wound infection predicted by the nomogram model reached 0.93, corresponding to a maximum predicted infection probability of 92.68%. The area under the receiver operating characteristic curve for the nomogram model was 0.869 (P < 0.001) and 0.861 (P < 0.001). The comparison of NLRP3 genotypes between the two groups showed that the proportion of the GG genotype was significantly higher in the infection group than the CC and CG genotypes (51.43% vs 29.90% and 38.98%, respectively). In patients with the GG genotype, the associations between age >65 years, diabetes and abnormal TEWL with wound infection remained significant (all P < 0.05), indicating that these clinical risk factors are particularly prevalent among GG carriers.

Conclusion: This study identified the independent risk factors for postoperative wound infection. Patients with the G allele have a higher risk of postoperative infection, and NLRP3 gene polymorphism is closely associated with the risk factors included in the model. The association between NLRP3 gene polymorphisms and the risk of postoperative infection provides a new molecular biological indicator for prognostic evaluation.

Introduction: To characterize the genomic architecture of carbapenemase-producing Pseudomonas juntendi harboring bla _VIM-2, elucidate genetic mechanisms underlying carbapenem resistance, and evaluate mobile genetic element (MGE)-mediated dissemination pathways using Oxford Nanopore and Illumina sequencing were combined for hybrid genome assembly approaches.

Methods: Hybrid Nanopore-Illumina whole-genome sequencing was applied on two P. juntendi isolates (L2353hy/L2891hy) recovered from distinct human fecal samples. L2353hy and L2891hy were identified as P. juntendi by ANI analysis. Comparative pangenomics identified resistance determinants and phylogenetic relationships, and SNP distances were calculated using SNP-dists. Plasmid profiles were verified using S1 nuclease pulsed-field gel electrophoresis (S1-PFGE).

Results: Both strains exhibited a multidrug resistance profile, comprising 13 antimicrobial resistance genes (ARGs), including bla _VIM-2, bla _OXA-246, and tet(A). Core genome phylogeny demonstrated clonal propagation of two VIM-producing P. juntendi strains. Notably, these two isolates were closely linked to P. juntendi yb_3 (a fish intestinal isolate; Wenzhou, China).

Conclusion: This study reports two clonally related P. juntendi strains harboring bla _VIM-2 isolated from human fecal microbiota, expanding the genomic understanding of carbapenem-resistant P. juntendi. The close phylogenetic relationship between these human isolates and an animal-derived strain (P. juntendi yb_3) underscores bidirectional resistance gene flow at the human-animal interface. Our findings support a One Health-oriented surveillance approach to mitigate the dissemination of carbapenemase-producing pathogens.

Purpose: Gut colonization of carbapenem-resistant Enterobacterales (CRE) poses a significant risk for systemic infections, but the mechanisms driving resistance dissemination are poorly understood. This study aimed to investigate whether outer membrane vesicles (OMVs) secreted by gut-colonized CRE can enter the human circulatory system and mediate extracellular antibiotic resistance through functional carbapenemases and resistance genes.

Patients and methods: We conducted comparative proteomic analyses of OMVs isolated from parental CRE strains and patient plasma samples. Antibiotic degradation assays were performed to evaluate OMV-mediated hydrolysis of imipenem and meropenem. In vitro experiments assessed the protective effects of OMVs on carbapenem-susceptible Escherichia coli and Pseudomonas aeruginosa. Additionally, a Galleria mellonella infection model was used to examine OMV-mediated bacterial survival under carbapenem pressure.

Results: Plasma-derived OMVs exhibited proteomic profiles similar to bacterial OMVs, including carbapenemase components, and demonstrated comparable antibiotic-degrading activity. These OMVs hydrolyzed 60-75% of imipenem and meropenem within 24 hours, protecting susceptible bacteria from growth inhibition in vitro. Although no horizontal gene transfer was observed, OMVs enhanced Klebsiella pneumoniae survival under carbapenem pressure in the G. mellonella model, increasing larval survival rates by 25%.

Conclusion: Our findings reveal a novel OMV-mediated extracellular resistance mechanism that operates independently of genetic transfer, promoting bacterial persistence in the bloodstream. This study provides key insights into the role of OMVs in clinical treatment failure and identifies potential therapeutic targets to combat antibiotic resistance dissemination.