Colistin monotherapy or combination for the treatment of bloodstream infection caused by Klebsiella pneumoniae: a systematic review and meta-analysis.

BACKGROUND: Bloodstream infection of Klebsiella pneumoniae (BSI-KP) were associated with increased mortality. Klebsiella pneumoniae was tested to susceptible to colistin by E-test and broth microdilution method in clinical laboratory. This study aimed to assess the efficacy of colistin versus tigecycline, carbapenem monotherapy and combination in the treatment of BSI-KP. METHODS: Electronic databases such as PubMed, Web of Science and Embase were searched. The last search was in November 24th, 2022, addressing the colistin, carbapenems and tigecycline monotherapy and combination treatments in patients with BSI-KP. The primary outcomes were 30-day or 28-day mortality. OR where available with 95% CI were pooled in random-effects meta-analysis. RESULTS: Following the outlined search strategy, a total of 658 articles were identified from the initial database searching. Six studies, 17 comparisons were included. However, they all were observational design, lacking high-quality randomized controlled trials (RCTs). Moderate or low-quality evidences suggested that colistin monotherapy was associated with an OR = 1.35 (95% CI = 0.62-2.97, P = 0.45, Tau2 = 0.00, I2 = 0%) compared with tigecycline monotherapy, OR = 0.81 (95% CI = 0.27-2.45, P = 0.71, Tau2 = 0.00, I2 = 0%) compared with carbapenem monotherapy. Compared with combination with tigecycline or carbapenem, Colistin monotherapy resulted in OR of 3.07 (95% CI = 1.34-7.04, P = 0.008, Tau2 = 0.00, I2 = 0%) and 0.98 (95%CI = 0.29-3.31, P = 0.98, Tau2 = 0.00, I2 = 0% ), respectively. CONCLUSIONS: Colistin, carbapenem and tigecycline monotherapy showed similar treatment effects in patients who suffered from BSI-KP. Compared with colistin monotherapy, colistin combined tigecycline therapy might play the synergism effects. TRIAL REGISTRATION: retrospectively registered.

Baicalein Inhibits Plasmid-Mediated Horizontal Transmission of the blaKPC Multidrug Resistance Gene from Klebsiella pneumoniae to Escherichia coli.

Carbapenem-resistant bacterial infections pose an urgent threat to public health worldwide. Horizontal transmission of the ß-lacatamase Klebsiella pneumoniae carbapenemase (blaKPC) multidrug resistance gene is a major mechanism for global dissemination of carbapenem resistance. Here, we investigated the effects of baicalein, an active ingredient of a Chinese herbal medicine, on plasmid-mediated horizontal transmission of blaKPC from a meropenem-resistant K. pneumoniae strain (JZ2157) to a meropenem-sensitive Escherichia coli strain (E600). Baicalein showed no direct effects on the growth of JZ2157 or E600. Co-cultivation of JZ2157 and E600 caused the spread of meropenem resistance from JZ2157 to E600. Baicalein at 40 and 400 µg/mL significantly inhibited the spread of meropenem resistance. Co-cultivation also resulted in plasmid-mediated transmission of blaKPC from JZ2157 to E600, which was inhibited by baicalein. Therefore, baicalein may be used in clinical practice to prevent or contain outbreaks of carbapenem-resistant infections by inhibiting the horizontal transfer of resistance genes across bacteria species.

Quantitative analysis of pathogens in the lower respiratory tract of patients with chronic obstructive pulmonary disease.

BACKGROUND: Bacterial infection of the lower respiratory tract is believed to play a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD) and acute exacerbations of COPD (AECOPD). This study investigates the potential relationship between AECOPD and the load of six common bacterial pathogens in the lower respiratory tract using real-time quantitative PCR (RT-qPCR) in COPD patients. METHODS: Protected specimen brush (PSB) and bronchoalveolar lavage fluid (BALF) samples from the lower respiratory tract of 66 COPD patients and 33 healthy subjects were collected by bronchoscopy. The load of Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae, Pseudomonos aeruginosa, Haemophilus influenzeae, and Moraxella catarrhalis were detected by RT-qPCR. RESULTS: High Klebsiella pneumoniae, Pseudomonos aeruginosa, Haemophilus influenzeae and Moraxella catarrhalis burden were detected by RT-qPCR in both PSB and BALF samples obtained from stable COPD and AECOPD patients compared with healthy subjects. The load of the above four pathogenic strains in PSB and BALF samples obtained from AECOPD patients were significantly higher compared with stable COPD patients. Finally, positive correlations between bacterial loads and inflammatory mediators such as neutrophil count and cytokine levels of IL-1ß, IL-6 and IL-8, as well as negative correlations between bacterial loads and the forced expiratory volume in one second (FEV1) % predicted, forced vital capacity (FVC) % predicted, and FEV1/FVC ratio, were detected. CONCLUSIONS: These findings suggest that increased bacterial loads mediated inflammatory response in the lower respiratory tract and were associated with AECOPD. In addition, these results provide guidance for antibiotic therapy of AECOPD patients.

[Th17 and Treg cell levels in patients with sarcoidosis and their relation to disease activation].

OBJECTIVE: To investigate the Th17 cell and Treg cell levels in patients with sarcoidosis, and their relation to disease activation and glucocorticoids treatment. METHODS: Twenty-three sarcoidosis patients admitted in Yinzhou People's Hospital from January 2009 to December 2013 and 25 healthy subjects (controls) were included in this study. The blood samples and bronchoalveolar lavage fluid (BALF) samples were collected in all patients before and after glucocorticoids treatment. The serum angiotensin converting enzyme (SACE) levels were detected. The percentages of Th17 cells and Treg cells in peripheral blood and BALF were determined by flow cytometry, the concentrations of cytokines in serum and supernatants of BALF were measured by enzyme-linked immunosorbent assay (ELISA). The levels of ROR-γt and Foxp3 mRNA transcripts in peripheral blood mononuclear cells (PBMC) were determined by real-time quantitative PCR. The potential correlation between the percentages of Th17 or Treg cells and SACE levels was evaluated. RESULTS: Compared with healthy controls, significantly higher frequencies of Th17 cells (4.34%±0.89% vs 1.60% ± 0.42%), lower frequencies of Treg cells (1.28% ± 0.37% vs 3.39% ± 0.50%) in peripheral blood were observed. Higher level of ROR-γt mRNA (21.31 ± 3.55 vs 3.63 ± 1.00) and lower level of Foxp3 mRNA (1.60 ± 0.24 vs 3.12 ± 0.76) in peripheral blood were detected in sarcoidosis patients in active stage (before glucocorticoids treatment) (all P<0.01). After the treatment of glucocorticoids, these index in peripheral blood were significantly improved (Th17 cells 2.16% ± 0.68%，Treg cells 2.21% ± 0.42%, ROR-γt mRNA 10.15 ± 1.93, Foxp3 mRNA 2.44 ± 0.38) ( all P<0.05). The changing trends of Th17 and Treg cell cytokines levels in serum were consistent with two type cells. Meanwhile, the changing trends of above index in BALF of patients treated by glucocorticoids were consistent with those in sarcoidosis patients in active stage. The increased ratios of Th17 cells to Treg cells were positively correlated with the level of serum SACE (r= 0.781). CONCLUSION: The imbalance of Th17 cells and Treg cells in peripheral blood and airway may be involved in the pathogenesis of sarcoidosis, which was associated with the activity of disease, and the treatment of glucocorticoids may achieve a therapeutic effect by correcting the immune imbalance.

Clinical features and treatment outcomes of Vibrio vulnificus infection in the coastal city of Ningbo, China.

Background: Vibrio vulnificus is a gram-negative, opportunistic pathogen common to warm waters worldwide. Human V. vulnificus infection is rare and typically affects those residing in coastal areas during the summer months, but it causes rapid deterioration and is fatal. Methods: The medical records of six patients with sepsis caused by V. vulnificus infection who were treated at the First Affiliated Hospital of Ningbo University from 2020 to 2022 were retrospectively reviewed. The patient demographics, clinical symptoms, laboratory test results, treatments, and outcomes are summarized. Results: Vibrio vulnificus infection was confirmed by blood or pus culture, 16S ribosomal DNA sequencing, and metagenomic next-generation sequencing. All six patients were male with pre-existing liver diseases and two reported consuming seafood before the onset of symptoms. Of the six patients, four succumbed to the disease, two recovered, and one underwent leg amputation. Conclusion: Vibrio vulnificus infection progresses rapidly and is highly fatal, thus prompt and aggressive treatment is necessary. Vibrio vulnificus infection should be considered in older (>40 years) patients with a history of liver disease and recent consumption of seafood or exposure to seawater, especially those residing in coastal areas during the summer months.

Analysis of CYP2C19 gene polymorphism and influencing factors of pharmacological response of clopidogrel in patients with cerebral infarction in Zhejiang, China.

Background: Certain genetic and non-genetic factors may cause damaged platelet inhibition by clopidogrel. We aimed to determine the effect of cytochrome P4502C19 (CYP2C19) polymorphism, along with other clinical factors, on the platelet response to clopidogrel in patients with acute ischemic stroke (AIS). Methods: A total of 214 patients with AIS receiving clopidogrel at a maintenance dose of 75 mg daily admitted to the Ningbo First Hospital between 1 January 2020, and 31 December 2021, were enrolled. Platelet aggregation analysis was performed to determine clopidogrel resistance. Quantitative real-time polymerase chain reaction (QRT-PCR) was used to determine CYP2C19 genotype. Other laboratory data on complete blood count and biochemical parameters were taken from patient medical files. Results: Among the 214 AIS patients treated with clopidogrel in the Ningbo population, the incidence of clopidogrel resistance was approximately 43.9%, and the distribution of CYP2C19 genotypes was highest for CYP2C19(*1/*2) (43.0%), followed by CYP2C19 (*1/*1) (38.8%). The distribution of alleles *1, *2, *3, and *17 was 62.1, 32.5, 4.9, and 0.5%, respectively. A chi-squared test showed that the gene frequencies of alleles *2 and *3 were significantly higher in the clopidogrel-resistant group than in the clopidogrel-sensitive group (p < 0.001), and a Mann-Whitney U-test showed that high HCY levels were significantly correlated with clopidogrel resistance (p < 0.001). Multi-factor logistic regression analysis demonstrated that mutant heterozygous genotype [OR 2.893; 95% confidence interval (CI) 1.456-5.748; p = 0.002], mutant homozygous genotype (OR 4.741; 95% CI 1.828-12.298; p = 0.001), and high HCY levels (OR 1.209; 95% CI 1.072-1.362; p = 0.002) were significantly associated with clopidogrel resistance. Conclusion: According to our results, carrying the CYP2C19*2/*3 allele and high HCY levels are independent risk factors for clopidogrel resistance after clopidogrel therapy in patients with AIS. These two factors should be considered prior to clopidogrel administration.

Multicenter Study of Colistin Heteroresistance in Carbapenem-Resistant Klebsiella pneumoniae Strains in China.

Colistin has been considered a last-line option for the treatment of infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP). Heterogeneous resistance to colistin leads to unexplained clinical colistin treatment failure for CRKP. Our study aimed to investigate the extent of colistin heteroresistance among CRKP strains in China. A total of 455 colistin-susceptible strains, collected from six tertiary care hospitals in China, were characterized. The overall rate of colistin heteroresistance was 6.2%, as determined by the population analysis profiles (PAPs). Genomic analysis revealed that 60.7% of the colistin-heteroresistant isolates belonged to the epidemic sequence type 11 (ST11) clone. Single-nucleotide polymorphisms (SNPs) suggested that 6 ST5216 strains shared the same origin. Each of the subpopulations had a ≥8-fold decrease in colistin MIC in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), which indicated that heteroresistance could be suppressed by an efflux pump inhibitor. In addition, our results suggested that the PhoPQ pathway plays an important role in the mechanisms of heteroresistance. IMPORTANCE The problem of CRKP has raised alarms concerning global health. Our study enriches the epidemiological study of colistin heteroresistance among CRKP strains in China, where the prevalence of this phenomenon was previously unknown. Importantly, colistin-heteroresistant strains may cause the failure of clinical treatment with colistin, even if the clinical laboratory reports that the strains are sensitive. The commonly used broth microdilution method is unable to detect this special phenomenon. Additionally, our results indicate that efflux pumps play a major role in colistin heteroresistance, and inhibitors can effectively reverse it. Our study is the first to provide a detailed analysis of the prevalence of colistin heteroresistance in China, as well as an analysis of the genetic mechanisms of this phenomenon.

A virus preservation solution that inactivates the virus while maintaining the virus particle intact.

Background: The global coronavirus disease 2019 (COVID-19) pandemic has caused immeasurable losses to society. An important part of disease prevention and control is to diagnose infected patients as soon as possible, and nucleic acid detection plays an important role in diagnosing diseases such as COVID-19. Reverse transcription-polymerase chain reaction (RT-PCR) is a common method for the diagnosis of COVID-19 infection, but the false negative rate of covid nucleic acid is currently very high. Methods: In this paper, HEK293T cells and lentivirus were used to verify the effect of virus preservation solution, fluorescence method was used to verify the inactivation effect of virus preservation solution, real-time fluorescence PCR experiment was used to verify that the genetic material in virus particles was not destroyed, and protein gel electrophoresis was used to verify the integrity of virus particles in the preservation solution. Results: In this study, we developed a new virus preservation solution using homogeneous reaction technology that can immediately inactivate the virus within 5 minutes at room temperature and maintain the stability of viral nucleic acid for at least 7 days. Importantly, we found that while our solution differed from existing commercial preservatives that contain guanidinium, analyzing the cycle threshold (Ct) showed that it still maintained virion integrity. Conclusions: These advantages could reduce false negatives and the risk of laboratory exposure to infection. In addition, our solution achieved room temperature preservation, which could aid in the transportation of samples. Therefore, this new sample preservation solution could provide significant benefits to the clinical detection of viruses such as COVID-19.

Dynamic change process of target genes by RT-PCR testing of SARS-Cov-2 during the course of a Coronavirus Disease 2019 patient.

We report the dynamic change process of target genes by RT-PCR testing of SARS-Cov-2 during the course of a COVID-19 patient: from successive negative results to successive single positive nucleocapsid gene, to two positive target genes (orf1ab and nucleocapsid) by RT-PCR testing of SARS-Cov-2, and describe the diagnosis, clinical course, and management of the case. In this case, negative results of RT-PCR testing was not excluded to diagnose a suspected COVID-19 patient, clinical signs and symptoms, other laboratory findings, and chest CT images should be taken into account for the absence of enough positive evidence. This case highlights the importance of successive sampling and testing SARS-Cov-2 by RT-PCR as well as the increased value of single positive target gene from pending to positive in two specimens to diagnose laboratory-confirmed COVID-19.

NLRP3 Inflammasome Involves in the Acute Exacerbation of Patients with Chronic Obstructive Pulmonary Disease.

The NLR pyrin domain-containing protein 3 (NLRP3) inflammasome, a multi-protein complex, produces the pro-inflammatory cytokines interleukin (IL)-1ß and IL-18, which may contribute to the development of airway inflammation in chronic obstructive pulmonary disease (COPD). The aim of this study was to explore the correlation between circulating and local airway NLRP3 inflammasome activation with acute exacerbation of COPD (AECOPD). mRNA levels of NLRP3, Caspase (Casp)-1, apoptosis-associated speck-like protein containing CARD (ASC), IL-18, and IL-1ß in peripheral blood mononuclear cells (PBMCs) and bronchial tissues were determined by real-time PCR in 32 smokers, 65 patients with AECOPD, 50 COPD patients in recovery stage, and 30 COPD patients in stable stage. The levels of IL-1ß and IL-18 in serum and bronchoalveolar lavage fluid (BALF) supernatants were measured by ELISA. The load of six common pathogens in BALF samples were determined by real-time PCR. The potential correlation between the mRNA levels of NLRP3, Casp-1, ASC, IL-18 or IL-1ß and the load of pathogens was evaluated individually. Significantly higher mRNA levels of NLRP3, Casp-1, ASC, IL-18, IL-1ß and higher levels of IL-18 and IL-1ß were found in patients with AECOPD than in smokers. These NLRP3 inflammasome mediators were significantly decreased when COPD patients in the same group became clinical stable. The increased mRNA levels of NLRP3 inflammasomes in bronchial tissues were positively correlated with the load of the six common pathogens in the lower respiratory tract. We conclude that systemic and local airway NLRP3 inflammasome activation is associated with the acute exacerbation, which might be predictive factors of the acute exacerbation and clinical outcomes in COPD patients.

Regulatory effects of vasoactive intestinal peptide on the migration of mature dendritic cells.

The neuropeptide vasoactive intestinal peptide (VIP), released within lymphoid organs from nerve terminals and/or immune cells, plays a significant anti-inflammatory role. It was reported that VIP can induce regulatory dendritic cells (DCs) and promote Th2-type responses. However, the regulatory effect of VIP on the migration and expression of chemokine receptors by DC is mostly unknown. In the present study, we show that VIP exerts a differential effect on the expression of CCR1 and CCR7 by lipopolysaccharide (LPS)-treated mature DCs (mDCs) at both protein and mRNA levels. It up-regulates CCR1 expression but down-regulates CCR7 expression in LPS-stimulated mature DC, thereby differentially regulating the migration of mature DCs in response to CCL5 and CCL19. Our data indicate that VIP functions as a key endogenous anti-inflammatory agent by inhibiting migration of mDCs to draining lymph nodes, thus preventing the induction of an inflammatory immune response.

[Anti-metastatic effect of vascular endothelial growth factor receptor 2 extracellular domain gene-modified dendritic cell vaccination in murine model with experimental pulmonary metastasis].

OBJECTIVE: To investigate the anti-metastatic effect of vascular endothelial growth factor receptor 2 extracellular domain gene-modified dendritic cell (DC-sVEGFR-2) vaccination. METHODS: Dendritic cells (DC) were electroporated with pcDNA3. 1/sVEGFR-2 plasmid DNA. Expression of sVEGFR-2 was determined by ELISA. For immunization, C57BL/6 mice were intravenously injected three times with 1 x 10(5) cells per mouse of DC, pcDNA3. 1-transfected DC (DC-vector) , DC-sVEGFR-2, or 100 microl of PBS at 7-day intervals. At 10 days after the last immunization, the immunized mice were subjected to assessment of cytotoxic T lymphocyte ( CTL) response to VEGFR-2, alginate bead analysis of tumor cell-induced angiogenesis, and observation of the anti-metastatic effect in B16 melanoma metastasis model. CTL activity was determined by a standard 4-h 51Cr release assay against VEGFR-2 + vascular endothelial cell line H5V, 3LL cells stably transfected with pcDNA3. 1/sVEGFR-2 (3LL,-sVEGFR-2), and VEGFR-2- cell lines EL-4 and 3LL. Monoclonal antibodies GK1.5 anti-CD4 and 2.43 anti-CD8 were used to deplete in vivo CD4 + T cells and CD8' T cells, respectively. RESULTS: DC-sVEGFR-2 could effectively express sVEGFR-2, whereas DC-vector and DC could not. Immunization of mice with DC-sVEGFR-2 significantly induce CTL activity against VEGFR-2 + cell lines H5V and 3LL-sVEGFR-2, however, no significant CTL activity was observed when VEGFR-2- syngeneic cell lines EL-4 and 3LL. were used as target cells, implying this CTL activity was VEGFR-2 specific. Alginate bead analysis of in vivo neoangiogenesis showed that the inhibition reached 50% in mice vaccinated with DC-sVEGFR-2 compared with mice vaccinated with DC, DC-vector or PBS. Anti-metastatic experiment showed that profound reduction in pulmonary metastases was found in mice immunized with DC-sVEGFR-2, while mice immunized with PBS, DC, DC-vector developed extensive pulmonary metastases. The number of tumor nodules on lung surface decreased by 81.9% in mice immunized with DC-sVEGFR-2 when compared with mice immunized with DC-vector (49.7+/-12.7 vs. 9.0+/-3.2). In vivo T cell subset depletion experiments showed that the anti-metastatic effect of DC-sVEGFR-2 vaccination was abrogated in CD8 + T cell-depleted but not in CD4+ T cell-depleted mice. CONCLUSION: Immunization of mice with DC-sVEGFR-2 could break self-tolerance and induce a significant CTL response to VEGFR-2, leading to profound inhibition of tumor-cell induced angiogenesis and metastasis. This anti-metastatic effect is mainly mediated by CD8+ T cells.

Imbalance of peripheral blood Th17 and Treg responses in patients with chronic obstructive pulmonary disease.

BACKGROUND: Autoimmune responses mediated by cluster of differentiation 4(+) T cells may contribute to the development of chronic obstructive pulmonary disease (COPD). However, little is known about the frequency of peripheral blood Th17 cells and of regulatory T cells (Tregs) in Chinese patients with COPD. This study is aimed at determining the frequency of circulating Th17 and Tregs in patients with moderate and severe COPD, heavy smokers and healthy controls (HC). METHOD: The percentages of circulating T-helper type (Th)17 cells and Tregs were determined by flow cytometry in 32 patients with moderate COPD, 33 patients with severe COPD, 35 smokers, and 31 HC. The concentrations of serum Th17- and Treg-related cytokines were measured by enzyme-linked immunosorbent assay (ELISA). The levels of retinoic acid orphan receptor (ROR)-γt and Forkhead box p3 (Foxp3) mRNA transcripts in peripheral blood mononuclear cells were determined by real-time polymerase chain reaction. The potential correlation between the percentages of Th17 Tregs, serum cytokines and lung function was evaluated. RESULTS: In comparison with that in the smokers and HC, significantly higher frequencies of Th17 cells and higher levels of ROR-γt mRNA transcripts and serum interleukin (IL)-17A, IL-6, IL-21, IL-22 and IL-23, but lower frequency of Tregs and lower levels of Foxp3 and serum IL-10 were detected in patients with moderate and severe COPD. The increased ratios of Th17 to Tregs were negatively correlated with the values of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and FEV1/FVC. CONCLUSIONS: An imbalance of circulating Th17 cells and Tregs is associated with the deterioration of pulmonary function in patients with moderate and severe COPD.

Imbalance of Th17/Treg cells in mice with chronic cigarette smoke exposure.

BACKGROUND: Recent studies have revealed that autoimmune responses mediated by CD4(+) T cells may contribute to the development of chronic obstructive pulmonary disease (COPD). Meanwhile, imbalance of Th17/Treg has been reported to play a key role in the pathogenesis of autoimmune diseases. However, information on Th17/Treg balance in COPD is relatively limited. METHOD: We established a mouse model of COPD induced by chronic cigarette smoke (CS) exposure. Th17 and Treg in lung tissue and peripheral blood were quantified by flow cytometry. The level of the specific transcription factors of both T cell subsets in lung tissue was determined by real-time PCR. The expressions of Th17- and Treg-related cytokines in serum and bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: We found that mice with chronic CS exposure showed significant increase in lung Th17 prevalence, retinoic acid orphan receptor (ROR)-γt mRNA and Th17-related cytokines (IL-17A, IL-6 and IL-23). Meanwhile, there was obvious decrease in Treg cell prevalence, Forkhead box (Fox) p3 mRNA and Treg-related cytokine IL-10, as compared to mice underwent sub-acute CS exposure and air-exposure. Similar tendency was also found for the Th17/Treg ratio in peripheral blood. CONCLUSIONS: Our study thus reveals that the Th17/Treg imbalance exists in mice with chronic CS exposure, suggesting its potential role in the breakdown of immune self-tolerance in COPD. Further research on regulation of Th17/Treg balance may provide insights into the development of new therapeutic targets for this disease.