Clinical characteristics of community-onset Clostridioides difficile infections at a tertiary hospital in mainland China: A fourteen-year (2010-2023) retrospective study.

BACKGROUND: Clostridioides difficile infection (CDI) is an increasingly common disease in healthcare facilities and community settings. However, there are limited reports of community-onset CDI (CO-CDI) in China. METHODS: We collected diarrheal stool samples from 3885 patients who went to outpatient department or emergency department in a tertiary hospital in China during 2010-2023, analyzed the correlation between patients' basic information and the detection rate of CDI. Besides, all stool samples from 3885 outpatients included were tested by culturing. Moreover, we randomly selected 89 patients' stools during the 14 years and isolated 126 C. difficile strains from them. The presence of toxin genes (tcdA, tcdB, cdtA, and cdtB) were confirmed by PCR. Toxigenic strains were typed using multilocus sequence typing (MLST). Susceptibility to 9 antimicrobials was evaluated using the E-test. RESULTS: 528 of 3885 patients (13.6 %) with diarrhea were finally diagnosed as CDI. The median age of patients included was 51 years (6 months-95 years), while the median of patients with CDI was older than patients with negative results [55.5 years (6 months-93 years) vs. 50 years (9 months -95 years), p < 0.001]. In winter, patients with diarrhea might be more likely to have CDI. The detection rate of CDI of patients in emergency department was much higher than those in other outpatients (20.7 % vs. 12.4 %, p < 0.001), and did differ from each outpatient departments (p < 0.05). There were 95 isolated strains detected as toxigenic C. difficile. Among these strains, 82 (86.3 %) had the tcdA and tcdB genes (A+B+) and 5 of these 82 strains were positive for the binary toxin genes (cdtA and cdtB) (A+B+CDT+). There were 15 different sequence types (STs) by multilocus sequence typing (MLST), while the most ST was ST-54 (23.2 %). ST types composition was relatively stable over the time span of this study. Some strains had high resistance to ciprofloxacin, clindamycin, and erythromycin. Twenty-three isolates (24.2 %) were multidrug-resistant. CONCLUSIONS: Outpatients with CDI were common among patients having diarrhea during this period in our hospital. Elderly patients and patients went to emergency department may be susceptible to CDI. Based on MLST, the result revealed that the C. difficile isolates had high genetic diversity and maintained stability in this period. All isolates were susceptible to metronidazole and vancomycin, and nearly one quarter of all isolates had multidrug resistance.

Deep learning enables contrast-robust super-resolution reconstruction in structured illumination microscopy.

Structured illumination microscopy (SIM) is a powerful technique for super-resolution (SR) image reconstruction. However, conventional SIM methods require high-contrast illumination patterns, which necessitate precision optics and highly stable light sources. To overcome these challenges, we propose a new method called contrast-robust structured illumination microscopy (CR-SIM). CR-SIM employs a deep residual neural network to enhance the quality of SIM imaging, particularly in scenarios involving low-contrast illumination stripes. The key contribution of this study is the achievement of reliable SR image reconstruction even in suboptimal illumination contrast conditions. The results of our study will benefit various scientific disciplines.

The additional value of 18F-FDG PET/CT imaging in guiding the treatment strategy of non-tuberculous mycobacterial patients.

OBJECTIVES: Non-tuberculous mycobacteria (NTM) infection is an increasing health problem due to delaying an effective treatment. However, there are few data on 18F-FDG PET/CT for evaluating the status of NTM patients. The aim of this study was to investigate the potential value of 18F-FDG PET/CT in guiding the treatment strategy of NTM patients. METHODS: We retrospectively analyzed the cases of 23 NTM patients who underwent 18F-FDG PET/CT. The clinical data, including immune status and severity of NTM pulmonary disease (NTM-PD), were reviewed. The metabolic parameters of 18F-FDG included maximum standardized uptake value (SUVmax), SUVmax of the most FDG-avid lesion (SUVTop), SUVTop/SUVmax of the liver (SURLiver), SUVTop/SUVmax of the blood (SURBlood), metabolic lesion volume (MLV), and total lesion glycolysis (TLG). The optimal cut-off values of these parameters were determined using receiver operating characteristic curves. RESULTS: There were 6 patients (26.09%) with localized pulmonary diseases and 17 patients (73.91%) with disseminated diseases. The NTM lesions had high or moderate 18F-FDG uptake (median SUVTop: 8.2 ± 5.7). As for immune status, the median SUVTop in immunocompromised and immunocompetent patients were 5.2 ± 2.5 and 10.0 ± 6.4, respectively, with a significant difference (P = 0.038). As for extent of lesion involvement, SURLiver and SURBlood in localized pulmonary and disseminated diseases were 1.9 ± 1.1 vs. 3.8 ± 1.6, and 2.7 ± 1.8 vs. 5.5 ± 2.6, respectively, with a significant difference (P = 0.016 and 0.026). Moreover, for disease severity, SUVmax of the lung lesion (SUVI-lung) and SUVmax of the marrow (SUVMarrow) in the severe group were 7.7 ± 4.3 and 4.4 ± 2.7, respectively, significantly higher than those in the non-severe group (4.4 ± 2.0 and 2.4 ± 0.8, respectively) (P = 0.027 and 0.036). The ROC curves showed that SUVTop, SURLiver, SURBlood, SUVI-lung, and SUVMarrow had a high sensitivity and specificity for the identification of immune status, lesion extent, and severity of disease in NTM patients. CONCLUSION: 18F-FDG PET/CT is a useful tool in the diagnosis, evaluation of disease activity, immune status, and extent of lesion involvement in NTM patients, and can contribute to planning the appropriate treatment for NTM.

Subacute in-stent thrombosis after carotid artery stenting in a patient with gene polymorphisms associated with aspirin and clopidogrel resistance: a case report.

BACKGROUND: Carotid artery stenting (CAS) is a key treatment option for moderate to severe carotid artery stenosis. Carotid stent thrombosis (CST), a rare complication of CAS, has gained significant attention because of its catastrophic nature. More evidences are needed to guide the diagnosis and treatment of CST. CASE PRESENTATION: This study reports a rare case of sub-acute CST following CAS in a 50-year-old male patient who had experienced repeated cerebrovascular events on the premise of taking antiplatelet drugs. He also suffered an occlusion of the left middle cerebral artery (MCA) in the M2 segment, likely caused by an embolus detached from the stent thrombus. The cause of CST in this patient was presumed to be dual antiplatelet resistance (AR), as indicated by genetic testing. After treated with guide catheter-directed thrombolysis, thrombus aspiration, and a second round of thrombolysis, his in-stent thrombus was basically cleared. His M2 occlusion was resolved by mechanical thrombectomy using the Solitaire FR/Stent with Intermediate Catheter Assisting technique. The patient recovered well after replacement of antiplatelet drugs, and no new thromboembolic event occurred during the 13-month follow-up period. CONCLUSIONS: The occurrence rate of AR-related CST may be underestimated as the cause of majority CST cases remains unclear. Implementation of genetic test for aspirin and clopidogrel resistance may be helpful to find the possible cause of CST and to avoid future repeated cerebrovascular events by replacement of antiplatelet drugs.

Compact Chromatic Confocal Lens with Large Measurement Range.

Spectral confocal sensors are effective for measuring displacements. The core of the spectral confocal measurement system is a dispersive objective lens that uses optical dispersion to establish a one-to-one correspondence between the focusing position and wavelength, achieving high-resolution measurements in the longitudinal direction. Despite significant progress in dispersive objective lenses for spectral confocal sensor systems, challenges such as a limited dispersion range, high cost, and insufficient measurement accuracy persist. To expand the measurement range and improve the accuracy of the spectral confocal sensor, we designed a compact, long-axial dispersion objective lens. This lens has a simple structure that requires only six lens elements, two of which form cemented doublets. The system length is 58 mm, with a working distance of 46 ± 6 mm and a dispersion range of 12 mm within the wavelength range of 450-656 nm. The lens has an object-side numerical aperture (NA) of 0.22 and an image-side NA between 0.198 and 0.24, ensuring high light energy utilization. Finally, a spectral confocal measurement system was constructed based on the designed dispersive objective lens, and performance evaluation tests were conducted. The test results showed that the system achieved a resolution of 0.15 µm and a maximum linear error of ±0.7 µm, demonstrating high-precision measurement capabilities. The proposed lens design enables the development of more portable and cost-effective spectral confocal sensors.

Characteristics and Source Apportionment of Volatile Organic Compounds in a Coastal Industrial Area: A Case Study in the Yangtze River Delta of China.

In recent years, the coastal area in East China has experienced elevated volatile organic compounds (VOCs) levels during specific periods. VOCs have become one of the major atmospheric pollutants in these areas. In this study, 64 compounds including alkanes, alkenes, halohydrocarbons, aromatics, and oxygenated VOCs (OVOCs) were obtained by the TO-15 method through a 12-month campaign in industrial, urban and suburban areas in the Yangtze River Delta of China. The overall trends of total VOC (TVOC) concentrations at eight sampling sites were as follows: winter > autumn > spring > summer. The proportion of VOC categories was various at industrial sites, while OVOCs and halohydrocarbons had high proportions at urban sites and suburban sites, respectively. Coating, vehicle emission, petrochemical source, industrial source, and gasoline volatilization were identified as the major VOC emission sources by the positive matrix factorization model. Petrochemical and coating sources were the prime VOC sources at industrial sites. Aromatics contributed the most ozone formation potential at industrial sites, while OVOCs provided the main contributions at both urban and suburban sites during four seasons. According to the health risk assessment, a high probability of non-carcinogenic risk existed at three industrial sites. Special attention should be given to certain VOCs, such as acrolein and 1,2-dibromoethane in industrial areas.

Biobased Agents for Single-Particle Detection with Optoacoustics.

Optoacoustic (OA, photoacoustic) imaging synergistically combines rich optical contrast with the resolution of ultrasound within light-scattering biological tissues. Contrast agents have become essential to boost deep-tissue OA sensitivity and fully exploit the capabilities of state-of-the-art OA imaging systems, thus facilitating the clinical translation of this modality. Inorganic particles with sizes of several microns can also be individually localized and tracked, thus enabling new applications in drug delivery, microrobotics, or super-resolution imaging. However, significant concerns have been raised regarding the low bio-degradability and potential toxic effects of inorganic particles. Bio-based, biodegradable nano- and microcapsules consisting of an aqueous core with clinically-approved indocyanine green (ICG) and a cross-linked casein shell obtained in an inverse emulsion approach are introduced. The feasibility to provide contrast-enhanced in vivo OA imaging with nanocapsules as well as localizing and tracking individual larger microcapsules of 4-5 µm is demonstrated. All components of the developed capsules are safe for human use and the inverse emulsion approach is known to be compatible with a variety of shell materials and payloads. Hence, the enhanced OA imaging performance can be exploited in multiple biomedical studies and can open a route to clinical approval of agents detectable at a single-particle level.

Novel SCCmec variants in clonal complex 398 and lineage-specific pseudo-SCCmec identified in ST88 MRSA from invasive bloodstream infections in China.

BACKGROUND: Methicillin resistance in Staphylococcus aureus is primarily due to the mecA gene found in highly diverse staphylococcal cassette chromosome mec (SCCmec) elements, with an increasing number of variants being continually discovered. OBJECTIVES: To characterize two novel SCCmec variants identified in clonal complex (CC) 398 strains and lineage-specific pseudo-SCCmec elements in the ST88 clone. METHODS: WGS and comparative genomic analysis were used to elucidate the SCCmec element diversity of representative isolates. RESULTS: The non-typeable 47 kb SCCmec found in the CC398 strain SKLX55795 represents a novel subtype of XIV, showing significant differences in structural organization and genetic content within the joining regions compared with the XIV element from the prototype strain SC792. This unique subtype comprised remnants from various mobile genetic elements that encode antimicrobial resistance genes, ultimately forming a large MDR region. Genome analysis of CC398 strain SKLX61416 revealed the presence of a novel 50 kb composite SCCmec with two distinct domains, carrying the ccr gene complexes 5/8 and containing genes for the detoxification of arsenic and sulphide. Further sequence analysis disclosed that 44.23% (23/52) of ST88 strains in our collection carried a lineage-specific pseudo-SCCmec, termed ΨSCCmecST88. This ΨSCCmecST88 harboured the mec gene complex C2, along with a series of genes associated with heavy metal resistance, but lacked an approximately 28 kb region encompassing the ccr gene complex. CONCLUSIONS: Our findings provide evidence for the ongoing evolution of SCCmec elements within the CC398 and ST88 clones, underscoring the need for further surveillance to understand the biological significance of these elements.

pH-Responsive Polymeric Micelle Dynamic Complexes for Selective Killing of Helicobacter pylori.

Helicobacter pylori, the world's most common chronic infection-causing pathogen, is responsible for causing gastric ulcers, the fourth-leading cause of cancer-related death globally in 2020. In recent years, the effectiveness of the current treatment regimen (two antibiotics and one proton pump inhibitor) has often been plagued with problems such as resistance and the undesired elimination of commensal bacteria. Herein, we report the synthesis of block and random copolycarbonates, functionalized with cationic guanidinium and anionic acetate functional groups, aimed at selectively killing H. pylori in the acidic environment of the stomach, while remaining nontoxic to the commensal bacteria in the gut. The compositions of the polymers were fine-tuned so that the polymers were readily dispersed in water without any difficulty at both pH 3.0 and 7.4. The self-assembly behavior of the polymers at different pH values by dynamic light scattering showed that the random and block copolymers formed stable micelles in a simulated gastric environment (pH 3.0) while aggregated at pH 7.4. Both polymers demonstrated stronger antibacterial activity against H. pylori than the guanidinium-functionalized homopolymer without any acetate functional group at pH 3.0. The block copolymer was significantly more bactericidal at pH 3.0 across the concentrations tested, as compared to the random copolymer, while it did not show significant toxicity toward rat red blood cells (rRBCs) and HK-2 cells or bactericidal effect toward E. coli (a common gut bacterium) and nor caused aggregation of rRBCs at its effective concentration and at physiological pH of 7.4. Additionally, both the block and random copolymers were much more stable against hydrolysis at pH 3.0 than at pH 7.4. This study provides insight into the influence of both polymer architecture and dynamic assembly on the bioactivities of antimicrobial polymers, where the disassembly of coacervates into narrowly dispersed micelles at pH 3 make them potent antimicrobials aided by the protonated carboxylic acid block.

Antimicrobial use, healthcare-associated infections, and bacterial resistance in general hospitals in China: the first national pilot point prevalence survey report.

The purpose of this study is to implement point prevalence survey (PPS), assess antimicrobial prescribing and resistance in general hospitals and clinical specialties in China, and compare them with similar data from other parts of the world. Twenty general hospitals in China were surveyed in October or November, 2019. A standardized surveillance protocol was used to collect data on patient demographics, diagnosis of infection, the prevalence and intensity of antimicrobial use, prescribing quality, bacterium type and resistance spectrum, and the prevalence and type of healthcare-associated infections (HAIs). Overall, 10,881 beds and 10,209 inpatients were investigated. The overall prevalence of antibiotic use was 37.00%, the use of antibiotic prophylaxis in surgical patients was high (74.97%). The intensity of antimicrobial use was 61.25 DDDs/100 patient days. Only 11.62% of antimicrobial prescriptions recorded the reason for prescribing. Intravenous or combination treatments comprised 92.02% and 38.07%, respectively, and only 30.65% of prescriptions referred to a microbiological or biomarker tests. The incidence of HAIs in all patients was 3.79%. The main associated factors for HAIs included more frequent invasive procedures (27.34%), longer hospital stay (> 1-week stay accounting for 51.47%), and low use of alcohol hand rubs (only 29.79% placed it bedside). Most of the resistant bacteria declined; only carbapenem-resistant Enterobacter is higher than previously reported. The prevalence of antibiotic use in general hospitals fell significantly, the overall bacterial resistance declined, and the incidence of HAI was low. However, the low quality of antimicrobial use requires urgent attention.

Comparison of the inoculum effect of in vitro antibacterial activity of Imipenem/relebactam and Ceftazidime/avibactam against ESBL-, KPC- and AmpC-producing Escherichia coli and Klebsiella pneumoniae.

OBJECTIVE: To evaluate effect of inoculum size of extended-spectrum ß-Lactamase (ESBL)-producing-, AmpC-producing-, and KPC-producing Escherichia coli and Klebsiella pneumoniae on the in vitro antibacterial effects of imipenem/relebactam (IMR) and ceftazidime/avibactam (CZA). METHODS: We compared the impact of inoculum size on IMR and CZA of sixteen clinical isolates and three standard isolates through antimicrobial susceptibility tests, time-kill assays and in vitro PK/PD studies. RESULTS: When inoculum size increased from 105 to 107 CFU/mL, an inoculum effect was observed for 26.3% (5/19) and 52.6% (10/19) of IMR and CZA, respectively; time-kill assays revealed that the concentration of CZA increased from ≥ 4 × MIC to 16 × MIC to reach 99.9% killing rate against K. pneumoniae ATCC-BAA 1705 (KPC-2-, OXA-9- and SHV-182-producing) and 60,700 (SHV-27- and DHA-1-producing). While for IMR, a concentration from 1 × MIC to 4 × MIC killed 99.9% of the four strains. When the inoculum size increased to 109 CFU/mL, neither IMR nor CZA showed a detectable antibacterial effect, even at a high concentration. An in vitro PK/PD study revealed a clear bactericidal effect when IMR administered as 1.25 g q6h when inoculum size increased. CONCLUSION: An inoculum effect on CZA was observed more frequent than that on IMR. Among the ß-lactamase-producing strains, the inoculum effect was most common for SHV-producing and KPC-producing strains.

Clinical features and 18F-FDG PET/CT for distinguishing of malignant lymphoma from inflammatory lymphadenopathy in HIV-infected patients.

BACKGROUND: It is vital to distinguish between inflammatory and malignant lymphadenopathy in human immunodeficiency virus (HIV) infected individuals. The purpose of our study was to differentiate the variations in the clinical characteristics of HIV patients, and apply 18F-FDG PET/CT parameters for distinguishing of malignant lymphoma and inflammatory lymphadenopathy in such patients. METHODS: This retrospective cross-sectional study included 59 consecutive HIV-infected patients who underwent whole-body 18F-FDG PET/CT. Of these patients, 37 had biopsy-proven HIV-associated lymphoma, and 22 with HIV-associated inflammatory lymphadenopathy were used as controls. The determined parameters were the maximum of standard uptake value (SUVmax), SUVmax of only lymph nodes (SUVLN), the most FDG-avid lesion-to-liver SUVmax ratio (SURmax), laboratory examinations and demographics. The optimal cut-off of 18F-FDG PET/CT value was analyzed by receiver operating characteristic curve (ROC). RESULTS: Considering the clinical records, the Karnofsky Performance Status (KPS) scores in patients with inflammatory lymphadenopathy were obviously higher than those in patients with malignant lymphoma (P = 0.015), whereas lymphocyte counts and lactate dehydrogenase (LDH) were obviously lower (P = 0.014 and 0.010, respectively). For the 18F-FDG PET/CT imaging, extra-lymphatic lesions, especially digestive tract and Waldeyer's ring, occurred more frequently in malignant lymphoma than inflammatory lymphadenopathy. Furthermore, the SURmax and SUVLN in malignant lymphoma were markedly higher than those in inflammatory lymphadenopathy (P = 0.000 and 0.000, respectively). The cut-off point of 3.1 for SURmax had higher specificity (91.9%) and relatively reasonable sensitivity (68.2%) and the cut-off point of 8.0 for the SUVLN had high specificity (89.2%) and relatively reasonable sensitivity (63.6%). CONCLUSION: Our study identified the distinctive characteristics of the clinical manifestations, the SURmax, SUVLN and detectability of extra-lymphatic lesions on 18F-FDG PET, and thus provides a new basis for distinguishing of malignant lymphoma from inflammatory lymphadenopathy in HIV-infected patients.

The evaluation of fecal microbiota transplantation vs vancomycin in a Clostridioides difficile infection model.

Vancomycin is the preferred treatment for Clostridioides difficile infection (CDI) but has been associated with a high recurrence rate of CDI in treated patients. Fecal microbiota transplantation (FMT) has emerged as a remarkably successful treatment for recurrent CDI (rCDI). Herein, we present a mouse model of CDI to further define the changes in intestinal inflammation, flora, and metabolites following FMT versus vancomycin treatment and to find the potential therapy to restore colonization resistance. Both FMT and vancomycin treatment could ameliorate CDI-induced clinical features and intestinal tissue damage, with decrease in the levels of inflammatory mediators like IL-1ß, IL-6, TNF-α, G-CSF, and MCP-1 in the colon and plasma. Observing the fecal gut microbiome profile revealed that unlike vancomycin, FMT could replenish intestinal microbiota by augmenting the relative abundance of the phylum Bacteroidetes and eliminating the abundance of the phylum Proteobacteria. FMT also reduced the levels of several carbohydrates, such as raffinose and fructose-6-phosphate, and amino acids, including tryptophan and glutamyl-valine, in the gut metabolome, thus suppressing C. difficile germination and growth. Our results suggest that the FMT-induced reconstruction of a specific gut community structure and restoration of metabolites promote the recovery of colonization resistance in mice better than vancomycin, thus offering new insights for the prevention of rCDI. KEY POINTS: • Both FMT and vancomycin ameliorate CDI-induced inflammatory response. • FMT restores a specific community structure and gut metabolites. • Mice treated with FMT may promote the recovery of colonization resistance and has a better outcome.

Quercetin protects against diabetic encephalopathy via SIRT1/NLRP3 pathway in db/db mice.

Epidemiological studies have found that diabetes and cognitive dysfunction are closely related. Quercetin has been certified with the effect on improving diabetes mellitus (DM) and cognitive impairment. However, the effect and related mechanism of quercetin on diabetic encephalopathy (DE) are still ambiguous. In this study, we used the db/db mice (diabetic model) to discover whether quercetin could improve DE through the Sirtuin1/NLRP3 (NOD-, LRR- and pyrin domain-containing 3) pathway. Behavioural results (Morris water maze and new object recognition tests) showed that quercetin (70 mg/kg) improved the learning and memory. Furthermore, quercetin alleviated insulin resistance and the level of fasting blood glucose. Besides, Western blot analysis also showed that quercetin increased the protein expressions of nerve- and synapse-related protein, including postsynapticdensity 93 (PSD93), postsynapticdensity 95 (PSD95), brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the brain of db/db mice. Quercetin also increased the protein expression of SIRT1 and decreased the expression of NLRP3 inflammation-related proteins, including NLRP3, the adaptor protein ASC and cleaved Caspase-1, the pro-inflammatory cytokines IL-1ß and IL-18. In conclusion, the present results indicate that the SIRT1/NLRP3 pathway may be a crucial mechanism for the neuroprotective effect of quercetin against DE.

Alterations of the Gut Microbiota in Patients With Coronavirus Disease 2019 or H1N1 Influenza.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is an emerging serious global health problem. Gastrointestinal symptoms are common in COVID-19 patients, and severe acute respiratory syndrome coronavirus 2 RNA has been detected in stool specimens. However, the relationship between the gut microbiome and disease remains to be established. METHODS: We conducted a cross-sectional study of 30 patients with COVID-19, 24 patients with influenza A(H1N1), and 30 matched healthy controls (HCs) to identify differences in the gut microbiota by 16S ribosomal RNA gene V3-V4 region sequencing. RESULTS: Compared with HCs, COVID-19 patients had significantly reduced bacterial diversity; a significantly higher relative abundance of opportunistic pathogens, such as Streptococcus, Rothia, Veillonella, and Actinomyces; and a lower relative abundance of beneficial symbionts. Five biomarkers showed high accuracy for distinguishing COVID-19 patients from HCs with an area under the curve (AUC) up to 0.89. Patients with H1N1 displayed lower diversity and different overall microbial composition compared with COVID-19 patients. Seven biomarkers were selected to distinguish the 2 cohorts (AUC = 0.94). CONCLUSIONS: The gut microbial signature of patients with COVID-19 was different from that of H1N1 patients and HCs. Our study suggests the potential value of the gut microbiota as a diagnostic biomarker and therapeutic target for COVID-19, but further validation is needed.

MDR Salmonella enterica serovar Typhimurium ST34 carrying mcr-1 isolated from cases of bloodstream and intestinal infection in children in China.

OBJECTIVES: Children are vulnerable to Salmonella infection due to their immature immune system. Cases of infection with mcr-1-harbouring Salmonella in child inpatients have not been reported in China before. METHODS: Salmonella isolates from gastroenteritis and bacteraemia were screened using primers targeting mcr-1. Complete genome sequences of mcr-1-harbouring isolates were determined using the PacBio RS II platform. The transferability of mcr-1-harbouring plasmids was verified by conjugation. RESULTS: We investigated two mcr-1-carrying polymyxin-resistant Salmonella enterica serovar Typhimurium ST34 isolates, S61394 and S44712, from bloodstream and intestinal Salmonella infection of two child inpatients, respectively. Both isolates were non-susceptible to commonly used antibiotics for children that compromised the success of clinical treatment and infection control. The mcr-1-harbouring plasmids pLS61394-MCR and pLS44712-MCR (from S61394 and S44712, respectively) were both conjugative pHNSHP45-2-like IncHI2-type epidemic plasmids carrying multiple resistance genes. Compared with pHNSHP45-2, a ∼33 kb insertion region encoding Tn7 transposition protein and heavy metal resistance proteins was identified in pLS61394-MCR, which might enhance adaptation of bacteria carrying this plasmid to various ecological niches. The phylogenetic tree of worldwide mcr-harbouring Salmonella indicated a host preference of mcr and a worldwide and cross-sectoral prevalence of the mcr-positive Salmonella ST34 clone. CONCLUSIONS: To our knowledge, for the first time we report completed whole genomes of mcr-1-positive MDR Salmonella Typhimurium ST34 isolated from infected children in China, suggesting that improved surveillance is imperative for tackling the dissemination of mcr-harbouring MDR Salmonella Typhimurium ST34.

Association between the rate of third generation cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae and antibiotic consumption based on 143 Chinese tertiary hospitals data in 2014.

This study sought to discuss the correlation between the third-generation cephalosporins (3GC)-resistant Escherichia coli and Klebsiella pneumoniae and antibiotic consumption intensity from 143 Chinese tertiary hospitals in 2014. With a retrospective design, the correlation between antibiotic consumption and 3GC-resistant E. coli and K. pneumoniae were performed. 3GC-resistant E. coli was significantly correlated with the consumption of all antibiotics (r = 0.252, p < 0.01), ß-Lactams antibiotics (r = 0.313, p < 0.01), ß-Lactams excluding combinations with ß-lactamase inhibitors (r = 0.365, p < 0.01), cephalosporin (r = 0.398, p < 0.01), cephalosporins excluding combinations with ß-lactamase inhibitors (r = 0.374, p < 0.01), 3GC (r = 0.321, p < 0.01), and 3GC excluding combinations with ß-lactamase inhibitors (r = 0.343, p < 0.01). 3GC-resistant K. pneumoniae was significantly correlated with the consumption of all antibiotics (r = 0.200, p < 0.05), ß-Lactams antibiotics (r = 0.232, p < 0.01), cephalosporin (r = 0.215, p < 0.05), 3GC (r = 0.383, p < 0.01), 3GC excluding combinations with ß-lactamase inhibitors (r = 0.245, p < 0.01), and ß-lactam-ß-lactamase inhibitor combinations (r = 0.218, p < 0.05). There was a significant relationship between the antibiotic consumption and the rates of 3GC-resistant E. coli and K. pneumoniae. Clinicians should grasp the indication of antibiotics use to reduce the production of drug-resistant bacteria.

Association between the rate of fluoroquinolones-resistant gram-negative bacteria and antibiotic consumption from China based on 145 tertiary hospitals data in 2014.

BACKGROUND: The purpose of the study is to discuss the correlation between the resistance rate of gram negative bacteria to fluoroquinolones (FQ) and antibiotic consumption intensity of 145 China tertiary hospitals in 2014. METHODS: This retrospective study adopted national monitoring data from 2014. Each participating hospital required to report annual consumption of each antibiotic, and the resistance rate of gram negative bacteria to FQ. Then the correlation between antibiotic usage and fluoroquinolones -resistant (FQR) rate was consequently investigated. RESULTS: One hundred forty-five hospitals were included in the study, and the median antibiotic consumption intensity was 46.30 (23.93-115.39) defined daily dosages (DDDs) per 100 patient-days. Cephalosporins ranks first in the antibiotics consumption, followed by fluoroquinolones, penicillins, and carbapenems. Fluoroquinolones resistance rate varied from hospital to hospital. The correlation analysis showed significant relationship between the percentage of FQR Escherichia coli and the consumption of FQs (r = 0.308, p<0.01) and levofloxacin (r = 0.252, p<0.01). For FQR Klebsiella pneumoniae, not only FQs (r = 0.291, p<0.01) and levofloxacin (r = 0.260, p<0.01) use but also carbapenems (r = 0.242, p<0.01) and overall antibiotics (r = 0.247, p<0.01) use showed significant correlation. The resistant proportion of FQR Pseudomonas aeruginosa was observed to be correlated with the consumption of all antibiotics (r = 0.260, p<0.01), FQs (r = 0.319, p<0.01) and levofloxacin (r = 0.377, p<0.01). The percentage of levofloxacin-resistant Acinetobacter baumannii was significantly correlated with the consumption of all antibiotics (r = 0.282, p<0.01), third-generation cephalosporins excluding combinations with beta-lactamase inhibitors (r = 0.246, p<0.01), FQs (r = 0.254, p<0.01) and levofloxacin (r = 0.336, p<0.01). However, the correlation of the ciprofloxacin-resistant A. baumannii and the antibiotics consumption was not found. CONCLUSIONS: A strong correlation was demonstrated between the antibiotic consumption and the rates of FQR gram-negative bacteria. As unreasonable antibiotics usage remains crucial in the proceeding of resistant bacteria selection, our study could greatly promote the avoidance of unnecessary antibiotic usage.

Longitudinal investigation of carriage rates and genotypes of toxigenic Clostridium difficile in hepatic cirrhosis patients.

Toxigenic Clostridium difficile (C. difficile) carriers represent an important source in the transmission of C. difficile infection (CDI) during hospitalisation, but its prevalence and mode in patients with hepatic cirrhosis are not well established. We investigated longitudinal changes in carriage rates and strain types of toxigenic C. difficile from admission to discharge among hepatic cirrhosis patients. Toxigenic C. difficile was detected in 104 (19.8%) of 526 hepatic cirrhosis patients on admission, and the carriage status changed in a portion of patients during hospitalisation. Approximately 56% (58/104) of patients lost the colonisation during their hospital stay. Among the remaining 48 patients who remained positive for toxigenic C. difficile, the numbers of patients who were positive at one, two, three and four isolations were 10 (55.6%), three (16.7%), two (11.1%) and three (16.7%), respectively. Twenty-eight patients retained a particular monophyletic strain at multiple isolations. The genotype most frequently identified was the same as that frequently identified in symptomatic CDI patients. A total of 25% (26/104) of patients were diagnosed with CDI during their hospital stay. Conclusions: Colonisation with toxigenic C. difficile strains occurs frequently in cirrhosis patients and is a risk factor for CDI.

Risk factors for Clostridium difficile infection in cirrhotic patients.

BACKGROUND: Cirrhotic patients are susceptible to Clostridium difficile infection (CDI), however, the high risk factors are not clear. The present study aimed to identify the risk factors in cirrhotic patients with CDI. METHODS: A total of 526 cirrhotic patients admitted to our hospital between May 2015 and October 2015 were included in this study. Stool samples were collected upon admission for the detection of CDI and toxin. CDI was monitored during the hospital stay. In total, 34 cases showed CDI. Then we analyzed the effects of age, sex, C. difficile colonization (CDC), multiple hospitalization, extended hospital stay, elevation of total bilirubin (TBIL), creatinine (Cr), Child-Pugh grade C, hepatic encephalopathy, hepatorenal syndrome, upper gastrointestinal hemorrhage, and exposure of antibiotics and proton pump inhibitor (PPI) on the CDI in cirrhotic patients. RESULTS: Patients in the CDI group had more frequent CDC, multiple hospitalization, and extended hospital stay compared to those in the non-C. difficile infection (NCDI) group. Patients in the CDI group had higher TBIL and Cr, and higher frequency of Child-Pugh grade C, hepatic encephalopathy, upper gastrointestinal hemorrhage compared with those in the NCDI group. Multiple logistic regression analysis indicated that age >60 years (OR=1.689; 95% CI: 1.135-3.128), multiple hospitalization (OR=3.346; 95% CI: 1.392-8.043), length of hospital stay >20 days (OR=1.564; 95% CI: 1.113-2.563), hypoproteinemia (OR=4.962; 95% CI: 2.053-11.996), CDC (OR=18.410; 95% CI: 6.898-49.136), hepatic encephalopathy (OR=1.357; 95% CI: 1.154-2.368), and exposure of antibiotics (OR=1.865; 95% CI: 1.213-2.863) and PPI (OR=3.125; 95% CI: 1.818-7.548) were risk factors of CDI. CONCLUSIONS: Age >60 years, multiple hospitalization, length of hospital stay >20 days, hypoproteinemia, CDC, hepatic encephalopathy, and exposure of antibiotics and PPI were risk factors for CDI in cirrhotic patients. These may contribute to the early diagnosis and monitoring of CDI in clinical practice.