Nationwide high prevalence of CTX-M and an increase of CTX-M-55 in Escherichia coli isolated from patients with community-onset infections in Chinese county hospitals

BACKGROUND

In order to investigate the epidemiology, molecular characteristics, and distribution of extended-spectrum β-lactamase (ESBL)- and AmpC-producing Escherichia coli from community-onset infections in Chinese county hospitals.

METHODS

E. coli isolates were collected from patients with community-onset infections in 30 county hospitals. ESBL activity was confirmed by double-disc diffusion. Genetic confirmation and molecular typing of ESBL- and AmpC-producing isolates was determined by PCR and DNA sequencing. ESBL-positive isolates were further characterised by multi-locus sequence typing.

RESULTS

Of 550 E. coli isolates, 256 (46.5%) carried ESBL genes and all were of the CTX-M type. The prevalence of ESBL-producing strains varied from 30.2% to 57.0% across different regions of China. Overall, 12 bla CTX-M subtypes were detected; the most abundant were bla CTX-M-14 (163/256 isolates, 64.5%), bla CTX-M-55 (47/256, 18.4%), and bla CTX-M-15 (31/256, 12.1%). CMY-2-like AmpC β-lactamases were detected in 11 strains, three of which co-existed with bla CTX-M. A total of 64 sequence types (STs) were detected in 256 ESBL-producing strains, including nine that were new. ST131 was the most abundant type (27 isolates, 12.7%), followed by ST69 (14 isolates, 6.6%), ST405 (14 isolates, 6.6%), and ST38 (12 isolates, 5.6%).

CONCLUSIONS

This study revealed that the widespread prevalence of ESBLs among outpatient infections has reached a high level in county hospitals. The CTX-M genotype was most dominant, comprising a variety of subtypes. This is the first time the incidence of CTX-M-55 has exceeded that of CTX-M-15 in China. No predominant ST was detected, suggesting that ESBL-producing E. coli strains originate in different clones.

Use and prescription of antibiotics in primary health care settings in China

IMPORTANCE

Appropriate antibiotic use is a key strategy to control antibacterial resistance. The first step in achieving this is to identify the major problems in antibiotic prescription in health care facilities, especially in primary health care settings, which is where most patients receive medical care.

OBJECTIVE

To identify current patterns of antibiotic use and explore the reasons for inappropriate prescription in primary health care settings in China.

DESIGN, SETTING, AND PARTICIPANTS

A total of 48 primary health care facilities in China were randomly selected from 6 provinces at various levels of economic development. Data for the years 2009 through 2011 from 39 qualifying facilities (23 city and 16 rural primary health care centers) were analyzed retrospectively. The study sample consisted of prescription records for 7311 outpatient visits and 2888 inpatient hospitalizations.

MAIN OUTCOMES AND MEASURES

General health center information, drug usage, disease diagnoses, and antibiotic use by outpatients and inpatients were surveyed. Cases of inappropriate antibiotic prescription were identified.

RESULTS

Most staff in the primary health care facilities had less than a college degree, and the medical staff consisted primarily of physician assistants, assistant pharmacists, nurses, and nursing assistants. The median (range) governmental contribution to each facility was 34.0% (3.6%-92.5%) of total revenue. The facilities prescribed a median (range) of 28 (8-111) types of antibiotics, including 34 (10-115) individual agents. Antibiotics were included in 52.9% of the outpatient visit prescription records: of these, only 39.4% were prescribed properly. Of the inpatients, 77.5% received antibiotic therapy: of these, only 24.6% were prescribed properly. Antibiotics were prescribed for 78.0% of colds and 93.5% of cases of acute bronchitis. Of the antibiotic prescriptions, 28.0% contained cephalosporins and 15.7% fluoroquinolones. A total of 55.0% of the antibiotic prescriptions were for antibiotic combination therapy with 2 or more agents. In nonsurgical inpatients in cities, the mean (SD) duration of antibiotic therapy was 10.1 (7.8) days. Of the surgical patients, 98.0% received antibiotics, with 63.8% of these prescriptions for prophylaxis.

CONCLUSIONS AND RELEVANCE

Antibiotics are frequently prescribed in Chinese primary health care facilities, and a large proportion of these prescriptions are inappropriate. Frequent and inappropriate use of antibiotics in primary health care settings in China is a serious problem that likely contributes to antimicrobial resistance worldwide.

Blockade of the T cell immunoglobulin and mucin domain protein 3 pathway exacerbates sepsis-induced immune deviation and immunosuppression

Sepsis is a life-threatening condition, but the pathophysiological basis and biomarkers for the monitoring of sepsis and as targets for therapy remain to be determined. We have shown previously that T cell immunoglobulin and mucin domain protein 3 (Tim-3), a negative immune regulator, is involved in the physiopathology of sepsis, but the underlying mechanisms remain unclear. In the present study, we showed that Tim-3 signalling modulated the response patterns of both macrophages and T helper cells in sepsis. Blockade of the Tim-3 pathway exacerbated sepsis-induced proinflammatory macrophage responses and lymphocyte apoptosis during the early phase of sepsis, and enhanced the shift to anti-inflammatory responses for both macrophages and T helper cells during the late phase of sepsis. Tim-3 signalling was found to regulate CD80 and CD86 expression on macrophages both in vivo and in vitro. Co-culture of T cells with Tim-3 knock-down macrophages led to a biased T helper type 2 (Th2) response, partially explaining how Tim-3 signalling shapes inflammation patterns in vivo. Further studies on this pathway might shed new light on the pathogenesis of sepsis and suggest new approaches for intervention.

Chemical compositions and antiproliferation activities of the chloroform fraction from Pyropolyporus fomentarius in K562 cells

Pyropolyporus fomentarius, a fungus of the polyporaceae family, has been used in the treatment of various diseases, such as gastroenteric disorder, hepatocirrhosis, oral ulcer, inflammation, and several cancers. This study was conducted to investigate the compositions and cell growth inhibition effects of P. fomentarius chloroform (CHCl3) fraction and to clarify the possible mechanisms. Gas chromatography–mass spectrometry analysis was performed to investigate the composition of the P. fomentarius CHCl3 fraction. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell membrane damage was evaluated with a scanning electron microscope and flow cytometry following propidium iodide and bis-(1,3-dibarbituric acid)-trimethine oxanol staining. Apoptosis was analyzed using annexin V-PE/7-amino-actinomycin D (7-AAD) staining. Generation of intracellular calcium ion (Ca2+), reactive oxygen species (ROS), and changes of mitochondrial membrane potential (Δ ψm) were detected by flow cytometry using fluo 3-acetoxymethyl ester, 2′,7′-dichlorofluorescin-diacetate, and rhodamine 123. Our obtained data indicate that P. fomentarius CHCl3 fraction could inhibit proliferation of K562 cells depending on both the dosage and the incubation time, cause cell membrane damage, influence intracellular [Ca2+]i variation, promote the yield of ROS, decrease the level of Δψm, and initiate the apoptotic response in K562 cells.

Combination of high-intensity focused ultrasound irradiation and hydroxyapatite nanoparticle injection to injure normal goat liver tissue in vivo without costal bone incision

The aims of this study were to evaluate the in vivo safety of intravenous nano-hydroxyapatite (nano-HA), to explore how nano-HA might influence the effects of high-intensity focused ultrasound (HIFU) on normal liver tissue, and to investigate whether intravenous nano-HA could enhance HIFU for hepatocellular carcinoma ablation in a goat model. The present study, for the first time, indicated that the delivery of abundant nano-HA into the body over short periods of time could be assembled by the hepatic reticuloendothelial system, subsequently leading to a rapid rise of ultrasound-induced overheating, and ultimately resulting in enlargement of the coagulation necrotic area for ablated hepatocellular carcinoma in goats both in vivo and ex vivo. On the other hand, therapeutic doses of nano-HA were much lower than the lethal dose, and consequently presented transient and mild abnormalities of hepatic enzymes and renal function during the first 24 h after nano-HA injection. These results suggested that the combined application of nano-HA and HIFU is potentially a more effective alternative option compared to surgery for hepatocellular carcinoma local ablation in a safe and feasible manner.

Genome sequencing and genomic characterization of a tigecycline-resistant Klebsiella pneumoniae strain isolated from the bile samples of a cholangiocarcinoma patient

Background

The relationship between Klebsiella pneumoniae and nosocomial and community-acquired infections is well known, and K. pneumoniae resistance to most antibiotics is increasing worldwide. In contrast, tigecycline remains active against many bacterial strains, and serves as a last resort for treating multi-drug resistant bacterial infections. That tigecycline nonsusceptibility among K. pneumoniae isolates has been reported worldwide is worrying. However, the mechanisms of tigecycline resistance in K. pneumoniae are less well known. We report the genome sequence and genomic characterization of tigecycline-resistant K. pneumoniae strain 5422 isolated from the bile samples of a patient with cholangiocarcinoma.

Results

We sequenced the K. pneumoniae strain 5422 genome using next-generation sequencing technologies. Sequence data assembly revealed a 5,432,440-bp draft genome and 57.1% G + C content, which contained 5397 coding sequences. The genome has extensive similarity to other sequenced K. pneumoniae genomes, but also has several resistance-nodulation-cell division (RND) efflux pump genes that may be related to tigecycline resistance.

Conclusions

K. pneumoniae strain 5422 is resistant to multiple antibiotics. The genome sequence of the isolate and comparative analysis with other K. pneumoniae strains presented in this paper are important for better understanding of K. pneumoniae multi-drug resistance. The RND efflux pump genes identified in the genome indicate the presence of an antibiotic resistance mechanism prior to antibiotics overuse. The availability of the genome sequence forms the basis for further comparative analyses and studies addressing the evolution of the K. pneumoniae drug resistance mechanism and the K. pneumoniae transcriptome.

Safety and efficacy of the modified peroral endoscopic myotomy with shorter myotomy for achalasia patients: a prospective study

Peroral endoscopic myotomy (POEM) has been developed as a minimally invasive endoscopic treatment for achalasia for years. However, the optimal length of submucosal tunnel and myotomy of muscle bundles during procedure of POEM has not yet been determined, so we aim to assess safety and efficacy of modified POEM with shorter myotomy of muscle bundles in achalasia patients. Consecutive achalasia patients had been performed modified POEM with shorter myotomy, and assessed by symptoms, high-resolution manometry, and barium swallow examinations before and 3 months after POEM for safety and efficacy evaluation. Modified POEM with shorter submucosal tunnel (mean length 6.8 cm) and endoscopic myotomy of muscle bundles (total mean length 5.4 cm) were completed in 46 consecutive achalasia patients. During the 3-month follow up in all cases, significant improvement of symptoms (a significant drop in the Eckardt score 8.4 ± 3.2 vs. 2.7 ± 1.9; P < 0.001), decreased lower esophageal sphincter pressure (39.4 ± 10.1 vs. 24.4 ± 9.1 mmHg; P < 0.001) and integrated relaxation pressure (38.6 ± 10.4 vs. 25.7 ± 9.6 mmHg; P < 0.01), and a drop in height of esophagus barium-contrast column (5.4 ± 3.1 vs. 2.6 ± 1.8 cm; P < 0.001) were observed. The frequencies of adverse events were lower in those under endotracheal anesthesia and CO2 insufflations compared with intravenous anesthesia and air insufflations. Only three patients were found to have gastroesophageal reflux disease on follow up. Modified POEM with shorter myotomy under endotracheal anesthesia and CO2 insufflations shows its good safety and excellent short-term efficacy in the treatment of achalasia. But further studies are warranted to assess the long-term efficacy.

Severe infective endocarditis with systemic embolism due to community associated methicillin-resistant Staphylococcus aureus ST630

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) are increasingly causing infective endocarditis over the past decade. Here we report a healthy man who developed a severe acute infective endocarditis with systemic embolism caused by CA-MRSA. The strain was recovered from repeated blood cultures and was characterized using molecular detection and genotyping. The S. aureus isolate was typed as ST630 SCCmecV with spa-type t4549, agrI/IV and was PVL-negative. This is the only case report, to our knowledge, of CA-MRSA infective endocarditis in China. This case highlights the emergence and geographical spread of life-threatening CA-MRSA infection within China.

A comparative study of Sr-incorporated mesoporous bioactive glass scaffolds for regeneration of osteopenic bone defects

Recently, the use of the pharmacological agent strontium ranelate has come to prominence for the treatment of osteoporosis. While much investigation is focused on preventing disease progression, here we fabricate strontium-containing scaffolds and show that they enhance bone defect healing in the femurs of rats induced by ovariectomy.

INTRODUCTION

Recently, the use of the pharmacological agent strontium ranelate has come to prominence for the treatment of osteoporosis due to its ability to prevent bone loss in osteoporotic patients. Although much emphasis has been placed on using pharmacological agents for the prevention of disease, much less attention has been placed on the construction of biomaterials following osteoporotic-related fracture. The aim of the present study was to incorporate bioactive strontium (Sr) trace element into mesoporous bioactive glass (MBG) scaffolds and to investigate their in vivo efficacy for bone defect healing in the femurs of rats induced by ovariectomy.

METHODS

In total, 30 animals were divided into five groups as follows: (1) empty defect (control), (2) empty defects with estrogen replacement therapy, (3) defects filled with MBG scaffolds alone, (4) defects filled with MBG + estrogen replacement therapy, and (5) defects filled with strontium-incorporated mesopore-bioglass (Sr-MBG) scaffolds.

RESULTS

The two groups demonstrating the highest levels of new bone formation were the defects treated with MBG + estrogen replacement therapy and the defects receiving Sr-MBG scaffolds as assessed by μ-CT and histological analysis. Furthermore, Sr scaffolds had a reduced number of tartrate-resistant acid phosphatase-positive cells when compared to other modalities.

CONCLUSION

The results from the present study demonstrate that the local release of Sr from bone scaffolds may improve fracture repair. Future large animal models are necessary to investigate the future relationship of Sr incorporation into biomaterials.

Effect of resection of localized pancreaticobiliary adenocarcinoma on angiogenic markers and tissue factor related pro-thrombotic and pro-angiogenic activity

In this study, 52 patients were studied to elucidate the relative impact of resection of localized pancreaticobiliary adenocarcinoma (PBC) on circulating factors of tumour-associated angiogenesis e.g. tissue factor bearing microparticles (TFMP) and vascular endothelial growth factor (VEGF) and their clinicopathological significance to angiogenesis markers in cancer tissue from PBC patients. Angiogenesis array analysis on serum samples revealed that surgical resection of tumour lesion in PBC patients affects the levels of a panel of angiogenesis-related molecules, including VEGF that was verified by ELISA to significantly reduce (median & IQR: 1003(369-2000) vs. 457(159-834) pg/ml; p<0.05). Correspondingly, a significant decrease in the angiogenic activity (decreased capillary tube formation; p<0.05) of serum samples after the surgery was also found. Despite a decrease in number of circulating TFMP after surgery, this did not reach statistical significance; there was a significant reduction in pro-coagulant activity (prolonged prothrombin time, p<0.001) post-operatively. In addition, the activity of total microparticles (MP activity assay, p<0.05) was decreased significantly. Immunohistochemical staining of tumour tissue revealed a strong correlation between the microvessel density (MVD) and VEGF expression. Also, higher levels of circulating TFMP or TF related activity (prothrombin time) correlated significantly with TF expression and MVD on tumour tissues from PBC patients. These findings suggest that in pancreaticobiliary adenocarcinoma TF related angiogenesis drivers are equally significant to VEGF ones, raising the clinical question of whether the effectiveness of angiogenesis targeting studies could be improved through the 'dual' targeting of these pathways in PBC.