Oral microbiota disorder in GC patients revealed by 2b-RAD-M.

BACKGROUND: Microbiota alterations are linked with gastric cancer (GC). However, the relationship between the oral microbiota (especially oral fungi) and GC is not known. In this study, we aimed to apply 2b-RAD sequencing for Microbiome (2b-RAD-M) to characterize the oral microbiota in patients with GC. METHODS: We performed 2b-RAD-M analysis on the saliva and tongue coating of GC patients and healthy controls. We carried out diversity, relative abundance, and composition analyses of saliva and tongue coating bacteria and fungi in the two groups. In addition, indicator analysis, the Gini index, and the mean decrease accuracy were used to identify oral fungal indicators of GC. RESULTS: In this study, fungal imbalance in the saliva and tongue coating was observed in the GC group. At the species level, enriched Malassezia globosa (M. globosa) and decreased Saccharomyces cerevisiae (S. cerevisiae) were observed in saliva and tongue coating samples of the GC group. Random forest analysis indicated that M. globosa in saliva and tongue coating samples could serve as biomarkers to diagnose GC. The Gini index and mean decreases in accuracy for M. globosa in saliva and tongue coating samples were the largest. In addition, M. globosa in saliva and tongue coating samples classified GC from the control with areas under the receiver operating curve (AUCs) of 0.976 and 0.846, respectively. Further ecological analysis revealed correlations between oral bacteria and fungi. CONCLUSION: For the first time, our data suggested that changes in oral fungi between GC patients and controls may help deepen our understanding of the complex spectrum of the different microbiotas involved in GC development. Although the cohort size was small, this study is the first to use 2b-RAD-M to reveal that oral M. globosa can be a fungal biomarker for detecting GC.

Discovery of novel Staphylococcus aureus penicillin binding protein 2a inhibitors by multistep virtual screening and biological evaluation.

Penicillin-binding protein 2a (PBP2a) is an essential protein involved in the resistance to ß-lactam antibiotics acquired by methicillin-resistant Staphylococcus aureus (MRSA) and is a potential antibacterial target. In the current study, we employed a strategy that combined virtual screening with biological evaluation to discover novel inhibitors of PBP2a. In this investigation, a hybrid virtual screening method, consisting of drug-likeness evaluation (Lipinski's Rule of Five and ADMET) and rigid (LibDock) and semi-flexible (CDOCKER) docking-based virtual screenings, was used for retrieving novel PBP2a inhibitors from commercially available chemical databases. 11 compounds were selected from the final hits and subsequently shifted to experimental studies. Among them, Hit 2, Hit 3, and Hit 10 exhibited excellent anti-MRSA ATCC 33591 activity and weak toxicity in vitro. The affinity of the three compounds to bind to PBP2a was further confirmed by surface plasmon resonance (SPR) experiments and molecular dynamics (MD) simulation. An inter-complex interaction study showed that all hit compounds adapted well to the allosteric site of the PBP2a protein. In addition, Hit 2 (with best binding affinity to PBP2a, KD = 1.29 × 10-7 M) significantly inhibits proliferation of MRSA clinical isolates. Together, the 3 hit compounds, especially Hit 2, may be potential non-ß-lactam antibiotics against MRSA and the work will provide clues for the future development of specific compounds that block the interaction of PBP2a with their targets.

Discovery of clinical isolation of drug-resistant Klebsiella pneumoniae with overexpression of OqxB efflux pump as the decisive drug resistance factor.

Background emergence of multidrug-resistant (MDR) bacterial strains is a public health concern that threatens global and regional security. Efflux pump-overexpressing MDR strains from clinical isolates are the best subjects for studying the mechanisms of MDR caused by bacterial efflux pumps. A Klebsiella pneumoniae strain overexpressing the OqxB-only efflux pump was screened from a clinical strain library to explore reverse OqxB-mediated bacterial resistance strategies. We identified non-repetitive clinical isolated K. pneumoniae strains using a matrix-assisted laser desorption/ionization time-of-flight (TOF) mass spectrometry clinical TOF-II (Clin-TOF-II) and susceptibility test screening against levofloxacin and ciprofloxacin. And the polymorphism analysis was conducted using pulsed-field gel electrophoresis. Efflux pump function of resistant strains is obtained by combined drug sensitivity test of phenylalanine-arginine beta-naphthylamide (PaßN, an efflux pump inhibitor) and detection with ethidium bromide as an indicator. The quantitative reverse transcription PCR was performed to assess whether the oqxB gene was overexpressed in K. pneumoniae isolates. Additional analyses assessed whether the oqxB gene was overexpressed in K. pneumoniae isolates and gene knockout and complementation strains were constructed. The binding mode of PaßN with OqxB was determined using molecular docking modeling. Among the clinical quinolone-resistant K. pneumoniae strains, one mediates resistance almost exclusively through the overexpression of the resistance-nodulation-division efflux pump, OqxB. Crystal structure of OqxB has been reported recently by N. Bharatham, P. Bhowmik, M. Aoki, U. Okada et al. (Nat Commun 12:5400, 2021, https://doi.org/10.1038/s41467-021-25679-0). The discovery of this strain will contribute to a better understanding of the role of the OqxB transporter in K. pneumoniae and builds on the foundation for addressing the threat posed by quinolone resistance.IMPORTANCEThe emergence of antimicrobial resistance is a growing and significant health concern, particularly in the context of K. pneumoniae infections. The upregulation of efflux pump systems is a key factor that contributes to this resistance. Our results indicated that the K. pneumoniae strain GN 172867 exhibited a higher oqxB gene expression compared to the reference strain ATCC 43816. Deletion of oqxB led a decrease in the minimum inhibitory concentration of levofloxacin. Complementation with oqxB rescued antibiotic resistance in the oqxB mutant strain. We demonstrated that the overexpression of the OqxB efflux pump plays an important role in quinolone resistance. The discovery of strain GN 172867 will contribute to a better understanding of the role of the OqxB transporter in K. pneumoniae and promotes further study of antimicrobial resistance.

Viral shedding pattern of severe fever with thrombocytopenia syndrome virus in severely ill patients: A prospective, Multicenter cohort study.

Background: Severe fever with thrombocytopenia syndrome (SFTS) is spreading rapidly in Asia. The pathway of SFTS virus shedding from patient and specific use of personal protective equipments (PPEs) against viral transmission have rarely been reported. The study was to determine SFTS virus (SFTSV) shedding pattern from the respiratory, digestive and urinary tract to outside in patients. Methods: Patients were divided into mild and severe groups in three sentinel hospitals for SFTS in Anhui province from April 2020 to October 2022. SFTSV level from blood, throat swabs, fecal/anal swabs, urine and bedside environment swabs of SFTS patients were detected by qRT-PCR. Specific PPEs were applied in healthcare workers contacting with the patients who had oropharyngeal virus shedding and hemorrhagic signs. Results: A total of 189 SFTSV-confirmed patients were included in the study, 54 patients died (case fatality rate, 28.57 %). Positive SFTSV in throat swabs (T-SFTSV), fecal/anal swabs (F-SFTSV) and urine (U-SFTSV) were detected in 121 (64.02 %), 91 (48.15 %) and 65 (34.4 %) severely ill patients, respectively. The levels of T-SFTSV, F-SFTSV and U-SFTSV were positively correlated with the load of SFTSV in blood. We firstly revealed that SFTSV positive rate of throat swabs were correlated with occurrence of pneumonia and case fatality rate of patients (P < 0.0001). Specific precaution measures were applied by healthcare workers in participating cardiopulmonary resuscitation and orotracheal intubation for severely ill patients with positive T-SFTSV, no event of SFTSV human-to-human transmission occurred after application of effective PPEs. Conclusions: Our research demonstrated SFTSV could shed out from blood, oropharynx, feces and urine in severely ill patients. The excretion of SFTSV from these parts was positively correlated with viral load in the blood. Effective prevention measures against SFTSV human-to-human transmission are needed.

Risk Factors for a Hospital-Acquired Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infection: A Five-Year Retrospective Study.

PURPOSE: This study aimed to describe trends in Klebsiella pneumoniae (KP) resistance in bloodstream infections (BSI) and to identify risk factors for a hospital-acquired carbapenem-resistant Klebsiella pneumoniae (CRKP) BSI and 28-day mortality from a hospital-acquired KP BSI. PATIENTS AND METHODS: We recorded the results of antimicrobial susceptibility testing of 396 KP-positive blood cultures from January 2016 to December 2020. A total of 277 patients with a KP BSI were included in this study, of which 171 had a hospital-acquired infection and 84 had a hospital-acquired CRKP BSI. Multivariate logistic regression analysis was used to identify risk factors for a hospital-acquired CRKP BSI and 28-day mortality from a hospital-acquired KP BSI. RESULTS: The proportion of hospital-acquired infections among KP BSI patients increased from 53.1% in 2016 to 72.8% in 2020. The detection rate of CRKP among KP BSI patients increased from 18.8% in 2016 to 37.7% in 2020. Multivariate logistic regression showed that ß-lactam/ß-lactamase inhibitor combinations (BLBLIs) exposure (P = 0.022, OR 2.863), carbapenems exposure (P = 0.007, OR 3.831) and solid organ transplantation (P <0.001, OR 19.454) were independent risk factors for a hospital-acquired CRKP BSI. Risk factors for a 28-day mortality from hospital-acquired KP BSI were CRKP BSI (P =0.009, OR 5.562), septic shock (P =0.002, OR 4.862), mechanical ventilation>96 hours (P =0.020, OR 8.765), and platelet counts <100×109/L (P =0.003, OR 4.464). CONCLUSION: The incidence of hospital-acquired KP BSI continues to rise and the proportion of CRKP BSI is also increasing. We believe that the use of the BLBLIs needs to be carefully evaluated in hospital-acquired infection. Hospital-acquired KP BSI Patients with CRKP BSI, septic shock, mechanical ventilation and deficiency of platelets are more likely to have a poor prognosis.

In vitro and in vivo Activity of Combinations of Polymyxin B with Other Antimicrobials Against Carbapenem-Resistant Acinetobacter baumannii.

PURPOSE: To study the in vitro and in vivo antibacterial activities of polymyxin B (PB) and other five antimicrobial agents, including imipenem (IMP), meropenem (MEM), tigecycline (TGC), sulbactam (SUL), and rifampicin (RIF), alone or in combination against carbapenem-resistant Acinetobacter baumannii (CRAB). METHODS: Microbroth dilution method was used to determine the minimum inhibitory concentration (MIC) of ten strains of CRAB against six antibacterial drugs, and the checkerboard method was used to determine the fractional inhibitory concentration index (FICI). A mouse pneumonia model was established by intranasal instillation of Ab5075 to evaluate the antibacterial activity in vivo. RESULTS: The resistance rate of ten CRAB strains to IMP, MEM, and SUL was 100%, that to PB and TGC was 0%, and that to RIF was 20%. When PB was used in combination with the other five antibiotics in vitro, it mainly showed synergistic and additive effects on CRAB. The synergistic effect of PB and RIF was maximal, followed by MEM and IMP but was weak with SUL and TGC. In vivo, compared to the model group (untreated with antibiotics), treatment group (six antibiotics alone and PB combined with the other five antibiotics) reduced the bacterial load in the lung tissue and the serum inflammatory factors (IL-1ß, IL-6, and TNF-α). The bacterial load and the inflammatory factors of the combined group decreased significantly than that of the single group (P<0.05). The IL-6 and TNF-α values of the PB combined with the RIF group were significantly lower than the two drugs used individually. CONCLUSION: The combination of PB and IMP, MEM, and RIF exerted robust in vitro synergistic effects on CRAB isolates. The combination of PB and the other five antimicrobial agents had a better effect in the mouse pneumonia model than single agent, while the combination of PB and RIF had the best effect.

Time Course of Severe Fever With Thrombocytopenia Syndrome Virus and Antibodies in Patients by Long-Term Follow-Up Study, China.

Objectives: The objective was to describe the changes of severe fever with thrombocytopenia syndrome virus (SFTSV) and antibody in the disease course and explore the relationship between antibody titers and patients' prognosis. Methods: The levels of SFTSV, virus-specific immunoglobulin M (IgM), immunoglobulin G (IgG) titers, and cytokines in 37 patients with severe fever with thrombocytopenia syndrome (SFTS) were measured dynamically by real-time PCR and ELISA during the disease course; IgG titers were followed up in 53 cases. The correlation analysis of antibody titers with individual serum cytokines was calculated using the Spearman test. Results: The average time of SFTSV duration in individual serum was 22.45 ± 7.6 days from onset. We found SFTSV turned negative within the 10th day from the onset in two patients. SFTSV-specific IgM seroconversion occurred as early as within 3 days from the onset, increased gradually within the first 2 months, decreased gradually 3 months later, and disappeared after 6 months in all the patients. The average time of SFTSV-specific IgG antibody seroconversion was at 17 days from onset in the patients; the time was later in severe cases than in mild cases (23 ± 1.4 vs. 14.3 ± 1.0 days, p < 0.0001). IgG titers were maintained at the peak levels during the periods from 6 months to 1 year and decreased from the second year gradually. Severe cases had higher IgG levels than mild cases and also had a slower decreasing trend. During follow-up, only one lost IgG antibody 7 years later; no chronic infection and sequela were found among the 53 patients. None of the patients had SFTSV reinfection even if they were bitten by ticks again. The correlation analysis showed a positive relationship between inflammatory factors and IgG antibody levels. Conclusion: IgM antibody has important value in early diagnosis of SFTS. A moderate inflammatory response is beneficial for production and duration of IgG antibodies.

Early-Warning Immune Predictors for Invasive Pulmonary Aspergillosis in Severe Patients With Severe Fever With Thrombocytopenia Syndrome.

Aspergillus-related disease was confirmed to be associated with immune disorders in patients, severe patients with severe fever with thrombocytopenia syndrome (SFTS) infected by novel phlebovirus were confirmed to have severe immune damage including cellular immunosuppression and cytokine storms. Secondary invasive pulmonary aspergillosis (IPA) in severe SFTS patients can increase fatality rate. This study investigated early-warning predictive factors of secondary IPA in severe SFTS patients. Receiver operating characteristic analysis was used to assess the value of immune parameters to predict IPA in SFTS patients. The cut-off values of CD4+ and CD8+ T-cell counts to predict IPA were 68 and 111 cells/mm3, with sensitivities of 82.6% and 72%, and specificities of 56.7% and 83.3%, respectively. Cut-off values of IL-6, TNF-α, IL-8, and IL-10 to predict IPA incidence in critically ill SFTS patients were 99 pg/mL, 63 pg/mL, 120 pg/mL, and 111 pg/mL, with sensitivities of 90.0%, 86.7%, 83.3% and 90.0% and specificities of 80.4%, 71.7%, 82.6% and 65.2%, respectively. Lower CD4+ and CD8+ T-cells counts, higher levels of IL-6, TNF-α, IL-8 and IL-10, higher incidence of pancreatic and renal damage, early antibacterial therapy of carbapenems, and intensive care unit admission were risk factors of IPA in SFTS patients. Multivariate logistic regression analysis indicated counts of CD4+ T-cells <68 cells/mm3 combined with CD8+ T-cells <111 cells/mm3 (odds ratio [OR] 0.218, 95% confidence interval [CI] 0.059-0.803, p=0.022), IL-6 >99 pg/ml combined with IL-10 >111 pg/ml (OR 17.614, 95% CI 2.319-133.769, p=0.006), and brain natriuretic peptide level >500 pg/ml (OR 13.681, 95% CI 1.994-93.871, p=0.008) were independent risk factors for IPA in SFTS patients. The mortality in the IPA group was significantly higher than in the non-IPA group (p=0.001). Early antifungal treatment of IPA patients was significantly associated with improved survival (log-rank, p=0.022). Early diagnosis of IPA and antifungal treatment can improve the prognosis of SFTS patients. Besides, we speculate SFTS may be as a host factor for IPA.

[Differences in immune damage between patients with severe fever with thrombocytopenia syndrome and patients with tsutsugamushi disease].

OBJECTIVE: To analyze the difference of immune damage between patients with severe fever with thrombocytopenia syndrome (SFTS) and patients with tsutsugamushi disease. METHODS: A prospective case-control study was conducted. Thirty-one patients with SFTS and 16 patients with tsutsugamushi disease admitted to the First Affiliated Hospital of Anhui Medical University from October 2014 to June 2017 were enrolled, and another 10 healthy people were enrolled as control. The counts of CD4+ and CD8+ T lymphocytes, and the proportion of CD3+ T lymphocytes, natural kill cells (NK cells), B lymphocytes and plasma cells were detected by flow cytometry. Thirty-four inflammatory mediators were determined by a multiplex Luminex® system synchronously. The differences of lymphocytes and cytokines between the two groups were compared. RESULTS: The proportion of CD3+ T lymphocytes, the counts of CD4+ and CD8+ T lymphocytes in SFTS patients were significantly lower than those in patients with tsutsugamushi disease (t values were 4.860, 9.411 and 5.030, respectively, all P < 0.01), and the proportion of NK cells and B lymphocytes were significantly higher than those in patients with tsutsugamushi disease (t values were 2.344 and 5.896, respectively, both P < 0.05). The proportion of plasma cells in peripheral blood of SFTS patients was (7.7±1.2)%, the highest proportion of plasma cells in severe SFTS patients was up to 30%, and all patients showed λ monoclonal cell group in plasma cells. No plasma cells were detected in tsutsugamushi disease patients. The abnormal expressions of interleukin-1 receptor antibody (IL-1RA), interleukin (IL-6, IL-15, IL-10, IL-8), tumor necrosis factor-α (TNF-α), γ-interferon (IFN-γ), granulocyte colony-stimulating factor (G-CSF), eosinophil chemotactic factor (Eotaxin), IFN-γ-inducible protein-10 (IP-10), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP-1α, MIP-1ß), platelet-derived growth factor (PDGF-AA, PDGF-AB/BB), activated regulatory normal T cells and secretion factors (RANTES) were found in patients with SFTS and tsutsugamushi disease. The levels of IL-1RA, IL-6, IL-15, IL-10, TNF-α, IFN-γ, G-CSF, Eotaxin, IL-8, IP-10, MCP-1 and MIP-1α in SFTS patients were significantly higher than those in patients with tsutsugamushi disease (Z values were 2.312, 2.447, 3.660, 5.444, 1.965, 2.402, 2.402, 2.997, 3.525, 2.481, 3.817, and 2.211, respectively, all P < 0.05), while PDGF-AA, PDGF-AB/BB and RANTES were significantly lower than those in patients with tsutsugamushi disease (Z values were 3.728, 2.514, 2.649, respectively, all P < 0.05). Correlation analysis showed that RANTES, PDGF-AA and PDGF-AB/BB levels were significantly positively correlated with the level of platelet in patients with SFTS and tsutsugamushi disease (SFTS: r values were 0.223, 0.365, 0.330; tsutsugamushi disease: r values were 0.263, 0.632, 0.407, respectively, all P < 0.05). In SFTS patients, compared with the survival group (n = 21), the CD3+ and CD4+ T lymphocytes in the death group (n = 10) significantly decreased, while the plasma cells significantly increased (t values were 3.980, 3.314 and 26.692, respectively, all P < 0.01); IL-1RA, IL-6, IL-15, IL-10, TNF-α, IFN-γ, G-CSF, Eotaxin, IL-8, IP-10, MCP-1, MIP-1α and MIP-1ß significantly increased, while PDGF-AA, PDGF-AB/BB and RANTES significantly decreased (Z values were 3.930, 4.014, 2.832, 3.592, 2.958, 3.508, 2.578, 3.254, 4.270, 3.465, 2.663, 3.085, 3.107, 3.639, 3.043 and 3.825, respectively, all P < 0.05). CONCLUSIONS: The immune function was impaired more seriously in SFTS patients than that in tsutsugamushi disease patients. Excessive humoral immunity and apoptosis of T lymphocytes are closely related to the death in SFTS patients. The detection of CD4 cells, plasma cells and proinflammatory and anti-inflammatory cytokines (e.g. IL-6, IL-10) had great clinical significance for the differentiation and illness evaluation in disease with SFTS or tsutsugamushi disease.

Minocycline and Fluconazole Have a Synergistic Effect Against Cryptococcus neoformans Both in vitro and in vivo.

In recent decades, the incidence of Cryptococcus neoformans infection, which causes cryptococcosis, has consistently increased. Fluconazole (FLU) is frequently used in the treatment of this disease, mainly in the immunocompromised population, and long-term therapy usually produces drug resistance. Research on antifungal sensitizers has gained attention as a possible means of overcoming this drug resistance. Minocycline (MINO) has an inhibitory effect in vitro on FLU-resistant Candida albicans, and the combination of MINO and FLU has a synergistic effect on FLU-resistant C. albicans. A synergistic effect of MINO/FLU has been reported against C. neoformans, but this effect has not been evaluated on FLU-resistant isolates. This study aimed to investigate the interaction of MINO and FLU against FLU-resistant C. neoformans both in vitro and in vivo. We found that the combination of MINO and FLU had a synergistic effect on FLU-resistant C. neoformans in vitro. For all FLU-resistant strains, the minimum inhibitory concentration (MIC) of FLU decreased significantly when used in combination with MINO, dropping from >128 µg/ml down to 4-8 µg/ml. Additionally, MINO and FLU had a synergistic effect on both susceptible and resistant C. neoformans biofilms, in which the MIC of FLU decreased from >256 µg/ml down to 4-16 µg/ml. Compared with FLU alone, the combination of MINO with FLU prolonged the survival rate of Galleria mellonella larvae infected with FLU-resistant C. neoformans, and also significantly decreased the fungal burden of infected larvae and reduced the tissue damage and destruction caused by FLU-resistant C. neoformans. These findings will contribute to the discovery of antifungal agents and may yield a new approach for the treatment of cryptococcosis caused by FLU-resistant C. neoformans.

Development and Validation of a Model for Predicting the Risk of Death in Patients with Acinetobacter baumannii Infection: A Retrospective Study.

PURPOSE: This study aimed to develop and validate a personalized prediction model of death risk in patients with Acinetobacter baumannii (A. baumannii) infection and thus guide clinical research and support clinical decision-making. PATIENTS AND METHODS: The development group is comprised of 350 patients with A. baumannii infection admitted between January 2013 and December 2015 in The First Affiliated Hospital of Anhui Medical University. Further, 272 patients in the validation group were admitted between January 2016 and December 2018. The univariate and multivariate logistic regression analyses were used to determine the independent risk factors for death with A. baumannii infection. The nomogram prediction model was established based on the regression coefficients. The discrimination of the proposed prediction model was evaluated using the area under the curve (AUC) of the receiver operating characteristic (ROC) curves and decision curve analysis (DCA). The calibration diagram was used to evaluate the calibration degree of this model. RESULTS: The infectious source, carbapenem-resistant A. baumannii (CRAB), hypoalbuminemia, Charlson comorbidity index (CCI), and mechanical ventilation (MV) were independent risk factors for death. The AUC of the ROC curve of the two groups was 0.768 and 0.792, respectively. The net income was higher when the probability was between 30% and 80%, showing a strong discrimination capacity of the proposed model. The calibration curve swung around the 45° oblique line, indicating a high degree of calibration. CONCLUSION: The proposed model helped predict the risk of death from A. baumannii infection, improve the early identification of patients with a higher risk of death, and guide clinical treatment.

The Regulation of Seventeen Inflammatory Mediators are Associated with Patient Outcomes in Severe Fever with Thrombocytopenia Syndrome.

Severe fever with thrombocytopenia syndrome (SFTS) as an emerging infection disease results in high morbidity and mortality in China. In this study, the circulating levels of 36 inflammatory mediators in 33 SFTS patients on days 3-7, 8-12 and 13-20 post-illness were measured by a multiplex Luminex® system dynamically. Among the patients, 15 severe patients recovered, 11 severe patients died within three weeks. We found IL-1RA, IL-6, IL-15, IL-10, TNF-α, IFN-γ, G-CSF, eotaxin, IL-8, IP-10, MCP-1, MIP-1α, MIP-1ß and fractalkine were significantly upregulated in SFTS patients. Elevated IL-15 and eotaxin in SFTS patients were reported firstly. The highest levels of pro-inflammatory and anti-inflammatory cytokines coexisted in fatal patients during the first week. Inflammatory mediators remained high levels when death occurred in fatal patients, they were recovered within three weeks in nonfatal patients. Our results showed the occurrence of inflammatory storm in SFTS patients were associated with the severity of SFTS. RANTES and PDGF were down regulated and remained significantly lower levels in fatal patients throughout the course of disease, the concentrations of RANTES and PDGF were remarkably positively correlated with the platelet count. Our results demonstrated that dysregulated inflammatory response was associated with disease pathogenesis and mortality in SFTS patients.

[The profile of antibiotic resistantpathogens isolated from ascites fluid patients in intensive care unit during past 12 years.

Objective: To investigate the profile and antibiotic resistance of bacteria in patients with ascites infection in intensive care unit (ICU) patients in order to provide a reference for rational clinical use of antibiotics. Methods: A retrospective analysis was conducted. The bacteria isolated from ascetic fluid patients admitted from January 1st, 2004 to October 31st, 2015 to ICU of the First Affiliated Hospital of Anhui Medical University were identified, and their susceptibility to antibiotics was analyzed. Patients, who were admitted from January 1st, 2004 to December 31st, 2009 were assigned to group A, and patients admitted afterwards were assigned to group B. Results: A total of 637 specimens of ascetic fluid were examined, with 185 positive culture (29.0%) during the 12 years, and 203 strains of bacteria were found. Among them 126 strains (62.1%) of gram-negative bacteria (G-), 54 (26.6%) of gram-positive bacteria (G+) and 23 (11.3%) strains of fungi were found. Compared the result of group B with that of group A, the proportion of G- bacteria was increased [71.2% (99/139) vs. 44.2% (27/64)], and that of G+ decreased [17.3% (24/139) vs. 46.9% (30/64)] in group B. The difference was statistically significant (χ2 = 20.34, P = 0.001). The main pathogenic bacteria were G-, and Enterobacteriaceae was the most common pathogenic bacteria in intra-abdominal infection of ICU patients. The isolation rate of Escherichia coli and Klebsiella pneumoniae(35.7%, 10.3%) ranked in the first and third in G- bacteria, respectively. The resistant rate of Escherichia coli against penicillin and third generation cephalosporin were > 95.0% and > 73.3%, and it showed a sensitive rate of 70% to ß-lactam/inhibitor, amikacin and minocycline, and a higher sensitivity to carbapenems and tigecycline (11.1%, 0). Forty-eight strains of non-fermentation bacteria were found with a rate of 23.7%. The positive rates of Acinetobacter baumannii in groups A and B were 7.8% (5/64) and 23.7% (33/139), respectively, and they ranked first among non-fermentation bacteria. Twenty strains (62.5%) multidrug-resistant Acinetobacter baumannii were found. Acinetobacter baumannii showed a resistance rate of 84.6% to cefoperazone/sulbactam, 35.3% to minocycline, and 53.3% to tigecycline. Candida albicans was the most commonly isolated fungus in intra-abdominal infections (87.5%). No strains resistant to common antifungal drugs were isolated. Conclusions: G- bacteria was the main pathogen in intra-abdominal infection in patients with ascites. Non-fermenters showed an increasing trend of producing infection, and the proportion of multidrug-resistant Acinetobacter baumannii infection increased year by year, and more attention should be taken by attending doctors.

Increase in the Prevalence of Resistance Determinants to Trimethoprim/Sulfamethoxazole in Clinical Stenotrophomonas maltophilia Isolates in China.

AIMS: This study was carried to reveal the genetic mechanisms of trimethoprim/sulfamethoxazole (SXT) resistance. METHODS: Among 300 clinical Stenotrophomonas maltophilia isolates from China, resistance determinants such as sul and dfrA genes, integrons and transposase were examined using PCR, DNA sequencing and thermal asymmetric interlaced PCR (TAIL-PCR). Data were analyzed using SPSS 20.0. RESULTS: Of the 300 isolates, 116 (38.7%) were resistant to SXT. An alarming trend of increased resistance to SXT were found over the 10-year period. The positive rates of sul and class 1 integrase (intI1) increased gradually with the development of SXT resistance over the 10-year period. Multiple logistic regression analyses indicated that the genes of qacEΔ1-sul1 (81% vs 46.2%, p = 0.000), sul2 (50.9% vs 9.8%, p = 0.000), intI1 (83.6% vs 65.8%, p = 0.000), dfrA12 (25% vs 3.3%, p = 0.000), dfrA17 (15.5% vs 3.8%, p = 0.000) and dfrA27 (4.3% vs 1.6%, p = 0.01) were more prevalent in SXT-resistant isolates than SXT-susceptible isolates except dfrA1(p = 0.83) and dfrA5(p = 0.18). Sequencing data revealed 12 types of resistance gene cassettes (aar-3-dfrA27, dfrA12-aadA2, dfrA17-aadA5, cmlA1, aacA4, aadA5, arr-3-aacA4, aadA1, aadB-aadA4, aacA4-catB8-aadA1, aadB-aac(6')-II-blaCARB-8 and aac(6')-II-blaCARB-8) located in the class 1 integron in 163 isolates (87% SXT-resistant vs 33.7% SXT-susceptible isolates, p = 0.000). A novel finding was the aar-3-dfrA27 (KC748137) gene cassette. The gene of sul2 linked to transposase in 50 SXT- resistant and 7 SXT- susceptible isolates was detected by TAIL-PCR. CONCLUSIONS: The findings demonstrated a higher prevalence of sul, dfrA, intI1 and resistance gene cassettes in class 1 integron in SXT-resistant clinical S. maltophilia isolates in China. The sul1 and dfrA genes located in integrons and the sul2 linked to transposase may imply wide and rapid dissemination of resistance gene in bacteria.