Objective To investigate the incidence rate, molecular epidemiology and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) infection. Methods A total of 119 Staphylococcus aureus strains isolated from January 2016 to December 2020 in general surgery of this hospital were collected retrospectively and divided into MRSA group and methicillin-sensitive Staphylococcus aureus group according to whether or not resistant to oxacillin. The clinical data of all patients infected with Staphylococcus aureus and drug sensitivity of Staphylococcus aureus were collected. Molecular typing was performed by multilocus sequence typing (MLST), resistance gene, virulence gene and biofilm gene were detected by polymerase chain reaction (PCR) method, and a case-control study was used to identify risk factors for MRSA infection. ResultsThe detection rate of MRSA was 57.98% (69/119), mainly was from pus specimens (80.67%, 96/119). The results of MLST showed that the dominant clone types were ST88 (37.68%, 26/69), ST951 (27.54%, 19/69) and ST59 (18.84%, 13/69). The results of PCR showed that the detection rates of mecA, mecC, Aac (6′ )/Aph (2′ ′ ), Aph (3)-Ⅲ, ant (4′ )- Ⅰ a, tetM, qnrA, panton-valentine leukocidin, fibronectin-binding protein A, staphylococcal enterotoxin A, staphylococcal enterotoxin B, α-hemolysins, intracellular adhesion A, staphylococcal accessory regulators A, and fibronectin-binding protein B in 69 strains of MRSA were 100%, 0.00%, 27.54%, 34.78%, 18.84%, 14.49%, 1.45%, 8.70%, 98.55%, 11.59%, 91.30%, 94.20%, 92.75%, 97.10% and 86.96%, respectively. Multivariate analysis showed that hospital transfer, wound infection, catheter related infection, drainage tube and history of cephalosporin using were risk factors for MRSA infection. ConclusionsThe detection rate of MRSA in general surgery of this hospital is high. ST88 is the most common clone type. The carrying rates of resistant-, virulence- and biofilm-related genes are high. Hospital transfer, wound infection, drainage tube, history of cephalosporin using etc. are high risk factors for MRSA infection. It is advised that invasive operation should be reduced, antibiotics should be used rationally, hand hygiene should be paid attention to, environmental sanitation disinfection should be carried out regularly, and the monitoring of MRSA bacteria should be strengthened, so as to reduce and control the infection and spread of MRSA.
Objective To investigate the effect ofstaphylococcal lipoteichoic acid (LTA-sa) on RAW264.7 cells differentiation into osteoclasts. Methods RAW264.7 cells were cultured with LTA-sa of 100 ng/mL (group A), LTA-sa of 200 ng/mL (group B), LTA-sa of 400 ng/mL (group C), receptor activator of nuclear factor κB (NF-κB) ligand (RANKL) of 100 ng/mL as positive control (group D), and equal volume of PBS as blank control (group E) respectively for 5 days. And then, tartrate resistant acid phosphatase staining (TRAP) was used to detect the formation of osteoclast-like cells, Image-Pro Plus 6.0 software to measure the areas of bone resorption pits in Corning Osteo Assay Surface (COAS) wells, and MTT assay to observe the proliferation activity of RAW264.7 cells in group A, B, C, and E. Results After cultured for 5 days, the formation of osteoclast-like cells and bone resorption pits were observed in all groups. The number of osteoclast-like cells and the area of bone resorption pits in groups A, B, C, and D were more than those in group E. And with the increased concentration of LTA-sa, the indexes in groups A, B, and C increased gradually, but were lower than those in group D, and differences were significant between groups (P<0.05). At 5 days after culture, there was no significant difference in absorbance value among the experimental groups (groups A, B, C, and E) (P>0.05). Conclusion LTA-sa has promoting effect on RAW264.7 cells differentiation into osteoclasts.
Methicillin-resistant Staphylococcus aureus is one of the important pathogens of healthcare-associated infections. In order to prevent and control the transmission of the drug-resistant organism in healthcare facilities, the Healthcare Infection Society and the Infection Prevention Society jointly conducted the guidelines for the prevention and control of methicillin-resistant Staphylococcus aureus in 2021. This article introduces the guide from the background, preparation process, main prevention and control measures and further studies, and compares the guidelines with the current prevention and control measures in China, so as to provide a methodological reference for preparation of the guide for domestic infection prevention and control practitioners, and provide evidence-based prevention and control strategies for clinical practice.
Objective Mesh infection may occur after incisional hernia repair using prosthetic mesh. Preparation of antibiotics-bonded meshes to prevent infection is one of the solutions. To evaluate the anti-infection effect of polypropylene mesh bonded norvancomycin slow-release microsphere by preparing the rat model of incisional hernia repair contaminatedwith Staphylococcus aureus. Methods The norvancomycin slow-release microspheres were prepared by emulsion and solvent evaporation method and they were bonded to polypropylene mesh (50 mg/mesh). The appearance of the microspheres was observed using scanning electronic microscope (SEM). The content of norvancomycin in microspheres and the release rate of the norvancomycin in norvancomycin-bonded polypropylene mesh were detected using high performance l iquid chromatography method. The rat models of incisional hernia were developed in 40 healthy Sprague Dawley rats, aged 10-11 weeks and weighing 200-250 g. The rats were divided randomly into the experimental group (norvancomycin-bonded polypropylene mesh repair, n=20) and the control group (polypropylene mesh repair, n=20). And then the mesh was contaminated with Staphylococcus aureus. The wound heal ing was observed after operation. At 3 weeks after operation, the mesh and the tissue around the mesh were harvested to perform histological observation and to classify the inflammatory reaction degree. Results The norvancomycin microsphere had integrated appearance and smooth surface with uniform particle diameter, 64% of particlediameter at 60 to 100 μm, and the loading-capacity of norvancomycin was 19.79%. The norvancomycin-bonded polypropylene patch had well-distributed surface and the loading-capacity of norvancomycin was (7.90 ± 0.85) mg/cm2. The release time of norvancomycin in vitro could last above 28 days and the accumulative release rate was 72.6%. The rats of 2 groups all survived to experiment completion. Wound infection occurred in 2 rats of the experimental group (10%) and 20 rats of the control group (100%), showing significant difference (χ2=32.727 3, P=0.000 0). The inflammatory reaction in experimental group was not obvious, grade I in 16 rats and grade II in 4 rats, and numerous inflammatory cell infiltration occurred in the control group, grade II in 3 rats and grade III in 17 rats, showing significant difference (Z=32.314, P=0.000). Conclusion The polypropylene mesh bonded norvancomycin slow-release microsphere has definite anti-infection effect in rat model of incisional hernia repair contaminated by Staphylococcus aureus.
摘要:目的: 金黄色葡萄球菌(金葡菌)的感染近年来已成为医院内的主要致病菌,而其耐药性也呈逐渐升高的趋势,为了解该菌在我院的感染和耐药情况,为临床合理使用抗生素提供科学依据。 方法 : 用经典生理生化鉴定方法,对各种临床标本主要来源于痰液和各种伤口脓液标本分离到的102株金葡菌进行生物学特性及药敏试验。 结果 : 从我们医院2007年5月至2009年8月所分离出来的102株金葡菌中青霉素耐药性8923%,氨苄青霉素耐药率为9385%,没有发现万古霉素耐药菌。 结论 : 除万古霉素外,耐药率较低的依次是利福平、苯唑青霉素、环丙沙星、呋喃妥因、阿米卡星、磺胺甲基异恶唑、红霉素,而青霉素G、氨苄青霉素、四环素耐药性情况非常严重,并且多重耐药,耐药性强,应引起临床的高度重视。Abstract: Objective: To analyze the bionomics and antimicrobial susceptibility of staphylococcus aureus, which was the main pathogenic bacterium with high drug tolerance in our hospital, in order to provide the rational use of antibiotics. Methods : Samples of one hundred and two staphylococcus aureus cases from sputamentum and pus were evaluated by classic physiology and biochemistry methods to test the bionomics and antimicrobial susceptibility. Results : The drug resistance rate to penicillin, penbritin and vancomycin was 8923%, 9385% and 0, separately. Conclusion : Besides vancomycin, the drug resistance rate of rifampicin, oxazocilline, ciprofloxacin, furadantin, amikacin, sulfamethoxazole and sulfamethoxazole increased one by one. The resistance to penicillin G, penbritin and tetracycline was serious, including multidrug resistant, which should be paid highly attention.
ObjectiveTo analyze the pathogenic bacteria distribution, structure and characteristics of drug resistance in patients with acute stroke complicated with pulmonary infection, in order to provide reference for the prevention of hospital infection and rational use of antimicrobial agents. MethodsA total of 864 clinical specimens of acute stroke complicated with pulmonary infection were chosen for study between January 2012 and December 2014. Separation and cultivation were done in accordance with the operation procedures regulated by the Ministry of Health. Drug sensitivity examination was done by Kirby-Bauer (k-b). Super-extensive spectrum β lactamase (ESBL) and methicillin resistant staphylococcus aureus (MRSA) were detected to analyze the bacterial species and resistance transition. ResultsA total of 864 samples were cultivated, in which G-bacteria accounted for 61.2%. The main pathogenic bacteria was Klebsiella pneumoniae bacteria, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumanmii and Staphylococcus aureus. Imipenem had high antimicrobial activity to G-bacilli, especially to Escherichia coli and Klebsiella pneumoniae bacteria. Linezolid, vancomycin and teicoplanin had high antibacterial activity to staphylococcus aureus. Vancomycin resistant Staphylococcus aureus was not found. Ciprofloxacin had high antibacterial activity to Pseudomonas aeruginosa, while imipenem had low antibacterial activity to Pseudomonas aeruginosa. Amikacin had high antibacterial activity to acinetobacter. ConclusionG-bacilli are predominant in acute stroke complicated with pulmonary infection. ESBLs and MRSA detection rate is high, and we should pay attention to the rational use of antibiotics to reduce drug resistance.
ObjectiveTo explore drug resistance, resistant mechanisms and resistant phenotypes of staphylococcus aureus (SA) isolated from wound secretion to macrolides-lincosamides-streptogramins (MLS). MethodsA retrospective design was used to collect clinical data and antimicrobial resistance profiles of SA in the First Affiliated Hospital and the Second Affiliated Hospital of Fujian Medical University and Anxi County Hospital from June, 2008 to October, 2015. SPSS 19.0 software was used for data analysis. ResultsA total of 127 isolates were included. The distribution of four resistant phenotypes of SA to MLS were all susceptibility(S) type (n=48, 37.8%), ML type (n=41, 32.3%), M/iCR+ type (n=22, 17.3%) and MLS type (n=16, 12.6%), respectively; There were three kinds of phenotypes caused by target changing including ML type, M/iCR+ type and MLS type, respectively. Moreover, no moxicaxin, linezolid or tigecyline resistant strain was detected, while quinolons and tetracyclines showed low-level resistant. ConclusionCompared with the different samples, the resistant phenotypes of SA isolated from wound secretion to MLS are few, and the total resistance ratio is low.
Objective To investigate the effect of aureolysin （Aur） on staphylococcus aureus biofilm formation of dacron biomaterial surfaces under different Aur concentration. Methods Ninety dacron biomaterials were divided into 3 groups （group A, group IA, control group） with random number table （30 piece in each group）. Dacron biomaterials were put into vials contained staphylococcus aureus （105 CFU/ml） respectively; then Aur was added to make the concentration at 400ng/ml in group A, and group B at 80ng/ml. The thickness and number of staphylococcus aureus biofilm on the surfaces of dacron biomaterials of each group were evaluated by confocal laser microscopy and scanning electron microscopy after incubating 6h, 16h, 24h, 30h, and 48h. Results The thickness and number of staphylococcus aureus biofilm on dacron biomaterials surfaces increased significantly with time dependence in control group. The thickness and number of staphylococcus aureus biofilm in group A were less than those in group B and control group at each time points （P〈0. 05）. The thickness and number in group B were significantly decreased than those in control group （P 〈 0. 05）. Conclusion The study shows that Aur can effectively inhibit the formation of staphylococcus aureus biofilm on dacron biomaterials surfaces with dose dependence.