Objective Titania and Ag containing nano-hydroxyapatite/polyamide 66 (TiO2-Ag-nHA/PA66) composite bone fill ing material has good biocompatibil ity and biological safety. To investigate the antibacterial effect and Ag+ release characteristics of TiO2-Ag-nHA/PA66 composite bone fill ing material containing different concentrations of Ag+ in vitro. Methods The n-HA/PA66 composite bone fill ing material A1 (material A1) was prepared by co-polymerization method, and TiO2-Ag-nHA/PA66 composite bone fill ing materials A2 and A3 (materials A2 and A3) were prepared by thesame way containing Ag+ of 0.22wt% and 0.64wt%, respectively, and the TiO2 content was 2.35wt%. The materials A2 and A3 were respectively immersed in 50 mL simulated body fluid (SBF), and Ag+ concentration was measured by atomic absorption spectrometry at 1, 3, 7, 14, 21, and 49 days. The inhibition ring test and colony count method were used to evaluate antibiotic effect against Staphylococcus aureus and Escherichia coli, the anti-adhesion capacity of Staphylococcus aureus and Escherichia coli was observed by scanning electron microscope (SEM). Results There was no significant difference in the Ag+ concentration between materials A2 and A3 at 1 day and 3 days (P gt; 0.05); and there were significant differences in the Ag+ concentration between materials A2 and A3 after 7 days (P lt; 0.05). The inhibition ring diameters of materials A2 and A3 to Staphylococcus aureus and Escherichia coli reached the maximum at 1 day, which were (13.40 ± 2.88), (9.40 ± 1.14) mm and (23.60 ± 1.14), (18.80 ± 0.84) mm, showing significant difference (P lt; 0.05) between materials A2 and A3 respectively; and then, the diameter of inhibition ring reduced with the time. The antibacterial effect of materials A2 and A3 against Staphylococcus aureus and Escherichia coli lasted 15, 33 days and 9, 24 days, respectively. No inhibition ring was observed around material A1 all the time. And the inhibitory rates of materials A2 and A3 were 89.74% ± 3.62%, 94.18% ± 2.05% and 78.65% ± 5.64%, 85.96% ± 2.50%; showing significant differences (P lt; 0.05) among materials A1, A2, and A3. SEM showed that bacterial adhesion of materials A2 and A3 was obviously fewer than that of material A1. Conclusion TiO2-Ag-nHA/PA66 composite bone fill ing material has antibacterial property against Staphylococcus aureus and Escherichia coli, and it has a good release effect in SBF.
Objective To prepare silver-containing hydroxyapatite coating (hydroxyapatite/Ag, HA/Ag) and investigate its antibacterial property and biocompatibil ity in vitro. Methods Vacuum plasma spraying technique was adopted to prepare HA/Ag coating on titanium alloy substrate (3% Ag). After incubating the HA/Ag and the HA coating under staphylococcus aureus and pseudomonas aeruginosa suspensions of 2% tryptic soy broth (TBS) medium for 2, 4 and 7 days, respectively, the biofilm on the coatings was examined by confocal laser scanning microscope, and the bacterial density and viable bacterial percentage of bacterial biofilm were calculated. Meanwhile, the micro-morphology of bacterial biofilm was observed by SEM, the cytotoxicity was detected via MTT and the biocompatibil ity of biofilm was evaluated by acute aemolysis test. Results Compared with HA coating, the bacterial biofilm’s thickness on the surface of HA/Ag coating witnessed no significant difference at 2 days after culture (Pgt; 0.05), but decreased obviously at 4 and 7 days after culture (P lt; 0.01). The bacterial density of the biofilm increased with time, but there was no significant difference between two coatings (P gt; 0.05) at 2, 4 and 7 days after culture. The viable bacterial percentage of the biofilms on the surface of HA/Ag coating decreased obviously compared with that of HA coating at 2, 4 and 7 days after cultureP lt; 0.01). The MTT notified the cytotoxic grade of both coatings was zero. The acute haemolysis assay showed that the hemolytic rate of HA/Ag and HA coating was 0.19% and 0.12%, respectively. Conclusion With good biocompatibil ity, significant antibacterial property against staphylococcus aureus and pseudomonas aeruginosa, no obvious cytotoxicity and no erythrocyte destruction, the vacuum plasma sprayed HA/Ag coating is a promising candidate for the surface of orthopedic metal implants to improve their osseointegration and antibacterial property.
Objective To investigate the differences in bacteria distribution and drug resistance of pathogens in patients with lower respiratory tract infection between respiratory general wards and respiratory intensive care unit ( RICU) .Methods All the clinical isolates fromsputumor secretion of lower respiratory tract from2007. 1-2010. 10 were analyzed retrospectively. Antibiotic susceptibility was tested by Kirby-Bauer method. Results The total number of isolated strains was 3202. Among 1254 strains isolated from respiratory general wards, Gram-positive bacteria accounted for 2. 63% , Gram-positive bacteria accounted for 42. 42% , and fungi accounted for 54. 95% . Streptococcus pneumoniae ranked first place among Gram-positive bacteria, accounting for 51. 52% . Haemophilus parainfluenzae bacillus ranked first place among Gramnegative bacteria, accounting for 21. 99% . Both were sensitive to the most commonly used antibiotics. Among 1948 strains isolated from RICU ward, Gram-positive bacteria accounted for 4. 52% , Gram-positive bacteria accounted for 37.73% , and fungi accounted for 57. 75% . Staphylococcus aureus ranked first place among Gram-positive bacteria, accounting for 52. 27% . Acinetobacter baumannii ranked first place in Gramnegative bacteria, accounting for 27. 35% . Both were resistant to most commonly used antibiotics. Pseudomonas aeruginosa had a higher rate of infection both in the general wards and RICU, and was resistant to most commonly used antibiotics.Conclusions In lower respiratory tract infection of respiratory general ward, Gram-positive bacteria with Streptococcus pneumoniae mainly and Gram-negative bacteria with Haemophilus parainfluenzae mainly are both sensitive to the most commonly used antibiotics. While in the RICU ward, Gram-positive bacteria infections with Staphylococcus aureus mainly and Gram-negative bacteria infections with Acinetobacter baumannii mainly are both resistant to most commonly used antibiotics.
ObjectiveTo probe into the writing quality and rational use of drugs for Emergency Department prescriptions in West China Hospital of Sichuan University. MethodsFrom January 2012 to December 2013, the prescriptions for emergencies were selected randomly. According to prescription management method and standard management of hospital prescription comment requirement, the quality of prescription was analyzed. ResultsFrom 2012 to 2013, the qualified prescription rate increased from 91.45% to 96.70%. The average number of drugs on each prescription was 1 or 2; the utilization rate of antibacterials was below 20.00%; the utilization rate of essential drugs increased from 60.68% to 66.15%; the utilization rate of generic drug name approached 100.00%. However, the utilization rate of injections increased from 82.92% to 85.67%. ConclusionBy prescription reviews, we have listed the problems, and intervened irrational prescription to improve the rate of qualified prescriptions. The high rate of injection utilization is a warning for us to take more effective, more specific and stricter intervention measures.
ObjectiveTo explore the risk factors for surgical patients associated with postoperative nosocomial infection through monitoring the infection conditions of the patients, in order to provide a scientific basis for the development of hospital infection control measures in a second-grade class-A hospital in Chengdu City. MethodsWe conducted the survey with cluster sampling as the sampling method and the uniform questionnaire in the departments of orthopedic, neural and thoracic surgery from July 2011 to June 2012. The main parameters we observed were the patients'general and surgical conditions, antibiotics usage and hospital infection situation. Data were analyzed using the National Nosocomial Infection Surveillance Network software and chi-square test of single factors. ResultsIn this survey, we monitored 50 cases of postoperative hospital infection. The infection rate was 7.73% and the highest infection rate was in the Neurosurgery Department. The main site of infection was lower respiratory tract, followed by surgical site. The different usage time of antimicrobial drug in perioperative period resulted in different infection rates, and the difference was statistically significant (χ2=601.50, P<0.005). The rate of adjusted postoperative hospital infection was higher than pre-adjusted rate except that of the neurosurgery doctor 4. The risk factors associated with hospital postoperative infection in our hospital were:patients'conditions including underlying disease, emergency surgery, type of anesthesia, operative duration, hospital stay and postoperative drainage. Most of the hospital infection cases were caused by bacteria of the gram-negative bacilli, and the major pathogens were Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii in our hospital. ConclusionThe hospital should particularly strengthen the prevention and control of hospital infection in patients after neurosurgical operations. For patients with basic diseases, we should actively improve the patients'physical conditions before operation and control the primary lesion. Targeted control measures should be taken for different factors related to surgery. Reasonable selection of antimicrobial agents should be based on the epidemic strains in our hospital.
ObjectiveTo explore the variation tendency of hospital infection and the antibacterial usage between 2011 and 2012,analyze the factors for hospitalization infection,and instruct on taking effective intervention measures,in order to reduce the rate of hospital infection,and thus to provide a scientific basis for the prevention and control of hospital infection. MethodsAll patients hospitalized in our hospital from 00:00 to 24:00 between September 21,2011 and August 16,2012 were investigated.By using the method of combined clinical investigation and case study,we asked the patients to fill the case questionnaires standardly,and analyzed the hospital infection cases on the survey day. ResultsA total of 1165 hospitalized patients were investigated from the year 2011 to 2012,and the actual check rate was 100%.A total of 46 cases of hospital infection occurred in 39 patients.The prevalence rate of hospital infection was 3.88% in 2011 and 2.80% in 2012.High rate hospital infections occurred in the Department of Neurosurgery which was 27.27% and Cardiothoracic surgery which was 16.67% in 2011.In 2012,the departments included ICU which was 28.57% and Internal Cardiovascular Medicine which was 9.09%.The main infection sites were respiratory tract,followed by urinary tract and superficial incisions.The usage rates of antibiotics were 63.07% and 40.56% respectively in the two years.There were significant difference in antibiotic use rate between the two years (P<0.01). ConclusionThe focus of future work is to strengthen the management of respiratory tract,urinary tract and surgical site infections,and to use antimicrobial drugs reasonably,in order to reduce hospital infection effectively.
ObjectiveTo investigate the distribution and antimicrobial resistance of the clinical strains isolated from the First Affiliated Hospital of Xi’an Jiaotong University in 2019 and provide a basis for clinical rational use of antibiotics.MethodsAll the clinical samples which were collected from January 1st to December 31st in 2019 were employed to determine antimicrobial resistance retrospectively. Results were interpreted according to Clinical and Laboratory Standards Institute 2019 breakpoints and analyzed by WHONET 5.6 software.ResultsA total of 6 784 nonduplicate strains were isolated in 2019, including 2 865 (42.2%) strains of Gram-positive bacteria and 3 919 (57.8%) strains of Gram-negative bacteria. The top five pathogens with the highest detection rate were Escherichia coli, Klebsiella pneumoniae, Enterococcus faecium, Pseudomonas aeruginosa, and Staphylococcus aureus. Methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase negative Staphylococcus accounted for 33.0% and 72.0%, respectively. The detection rate of vancomycin-resistant Enterococcus faecium was 1.0% and the detection rates of linezolid-resistant Enterococcus faecium and Enterococcus faecalis were 0.3% and 2.9%, respectively. As for the non-meningitis Streptococcus pneumoniae, the prevalence of penicillin-susceptible Streptococcus pneumoniae was 100% in the isolates from adults. Extended-spectrum β-lactamases-producing strains accounted for 58.2%, 33.6%, and 33.3% in Escherichia coli, Klebsiella spp., and Proteus mirabilis, respectively. The total detection rate of carbapenem-resistant Enterobacteriaceae was 7.8%, among which the detection rates of carbapenem-resistant Escherichia coli and carbapenem-resistant Klebsiella pneumoniae were 1.5% and 17.2%, respectively. The percentages of Pseudomonas aeruginosa strains resistant to imipenem and meropenem were 25.0% and 21.6%, respectively, and those of Acinetobacter baumannii were 73.8% and 74.2%, respectively.ConclusionsBacterial resistance is still serious in this hospital. It is necessary to strengthen rational drug use. At the same time, effective prevention and control measures should be taken to avoid cross-infection.
ObjectiveTo study the antibacterial activity of ceftazidime/avibactam against carbapenem-resistant Klebaiella pneumoniae (CRKP) in vitro and detect the resistance genes of CRKP, so as to provide reference for the treatment of patients with CRKP infection.MethodsA total of 120 CRKP strains isolated from clinical specimens from May 2014 to November 2017 were collected. The activitis of 11 antimicrobial agents against those CRKP strains were detected by broth microdilution method, and the genes related to resistance to ceftazidime/avibactam were detected by polymerase chain reaction in the 120 CRKP isolates.ResultsThe resistance rate of the 120 CRKP isolates against ceftazidime/avibactam was 16.67% (20/120), which was significantly lower than that against cefotaxime (100.00%), aztreonam (98.33%), ceftazidime (95.83%), cefoperazone/sulbactam (95.83%), meropenem (95.83%), imipenem (95.00%), levofloxacin(92.50%), amikacin (54.17%), minocycline (39.17%), and tegacycline (23.33%). Among the 20 CRKP strains resistant to ceftazidime/avibactam, there were 12 Klebsiella pneumoniae carbapenemase (KPC)-2-producing strains, 3 KPC-3-producing strains, 1 New Delhi metallo-β-lactamase-1 (NDM-1)-producing strain, and 1 oxacillin β-lactamase-48-producing strain; none of the 20 strains had KPC mutation.ConclusionsCeftazidime/avibactam is an effective agent agianst CRKP, and its resistance rate is significantly lower than that of other commonly used antimicrobial agents, especially other β-lactam antibiotics. In terms of resistance genes, except for one isolate producing NDM-1, no other known gene resistant to ceftazidime/avibactam has been found.
In recent years, bone implant materials such as titanium and titanium alloys have been widely used in the biomedical field due to their excellent mechanical properties and good biocompatibility. However, in clinical practice, bacterial adhesion to the material surface and postoperative infection issues may lead to implantation failure. Based on the antibacterial mechanism, this review elaborated on the antibacterial surface design of titanium implants from the aspects of anti-bacterial adhesion, contact sterilization and photocontrol sterilization. Surface modification of titanium or titanium-based alloy implants with different techniques can inhibit bacteria and promote osseointegration. Thus, the application range of multifunctional titanium-based implants in the field of orthopedics will be expanded.
Objective To review the research progress of new antibacterial hydrogels in the treatment of infected wounds in the field of biomedicine, in order to provide new methods and ideas for clinical treatment of infected wounds. Methods The research literature on antibacterial hydrogels at home and abroad was extensively reviewed in recent years, and the antibacterial hydrogels for the treatment of infected wounds were classified and summarized. Results Antibacterial hydrogels can be divided into three categories: inherent antibacterial hydrogels, antibacterial agent release hydrogels, and environmental response antibacterial hydrogels. The advantages and disadvantages of antibacterial materials, antibacterial mechanism, antibacterial ability, and biocompatibility were discussed respectively. Inherent antibacterial hydrogels have the characteristics of wide source, low cost, and simple preparation, but their antibacterial ability is relatively weak. New antimicrobial substances are added to antibacterial agent release hydrogels, such as antimicrobial peptides, metal ions, graphene materials, etc., providing a new therapeutic strategy for alternative antibiotic therapy. On the basis of the antibacterial material, environmental promoting factors such as photothermal effect, pH value, and magnetic force are added to the environmental response antibacterial hydrogels, which synergically enhances the antibacterial ability of the hydrogel, improves the precise regulation function and bionic effect of the hydrogel. ConclusionThe selection of a variety of materials, the addition of a variety of antibacterial agents, and the effect of various promoting factors make composite hydrogels show multiple characteristics. The development of antibacterial hydrogels that can effectively address practical clinical applications remains a significant challenge. In the future, expanding the application range of antibacterial hydrogels, constructing drug-loaded hydrogels, and developing intelligent hydrogels are still new areas that need to be explored and studied.