ObjectiveTo investigate the correlation between infection and capsular contracture by observing the effect of infection on the formation of the surrounding capsule after breast implants.
MethodsThree healthy adult female Diannan small-ear pigs underwent augmentation mammaplasty using miniature implants, which were randomly divided into group A (12 nipples), group B (10 nipples), and group C (12 nipples). Staphylococcus epidermidis (SE ATCC12228 and SE RP62A, 1.2×105 CFU/mL) was inoculated into the periprosthetics of groups B and C, and sterile PBS in group A before breast implants. Then the silica gel prosthesis was put, total 34 implants in 3 groups. After 13 weeks, the capsule was harvested to measure the capsular tension and weight. HE staining was used to observe the structure characteristics of the capsule and to measure the capsule thickness, Van-Gieson (VG) staining to observe the capsule collagen characteristics, and α-smooth muscle actin (α-SMA) immunocytochemistry staining to observe myofibroblasts in capsule.
ResultsPrimary healing of incision was obtained, and 3 small-ear pigs showed stable life indication. The complete fibrous capsule was observed after 13 weeks in 3 groups. Capsule tension showed no significant difference among 3 groups (P>0.05). Capsule weight was significantly greater in group C than in groups A and B (P<0.05). HE staining showed that capsule structure of the 3 groups was similar with obvious dense layer and loose layer, and the capsule thickness was also significantly greater in group C than in groups A and B (P<0.05), but no significant difference was found between groups A and B (P>0.05). VG staining showed that collagenous fiber in the capsule were more compact in group C than in groups A and B. The α-SMA immunocytochemistry staining indicated the myofibroblasts in capsule were the most in group C.
ConclusionInfection after breast implants has obvious impacts on the formation of the capsule, and there was a causal link between infection and capsular contracture.
Objective To evaluate the toxic effects of staphylococcus aureus exotoxins and neutrophils on retinal pigment epithelium (RPE) cells (RPEC). Methods An in-vitro model of bacteroidal endophthalmitis was established by co-culturing of human RPE cell line D407 and human peripheral blood neutrophils in the present of staphylococcus aureus exotoxins ATCC29213. The level of lactate dehydrogenase hydroxide（LDH）in the cuture supernant was measured, and the viability of RPE was evlauated by flow cytometry and Hoechst 33342/Propidium Iodide（PI）staining. Results When RPE cells were cultured with the exotoxin ATCC29213, the LDH level and necrotic RPE cells were positive proportional to the dosage of exotoxin, but only 250mu;l or 500mu;l of ATCC29213 had a statistical significant effect. When RPE cells were co-cultured with neutrophils in the present of ATCC29213 for 6 hours, 100mu;l of ATCC29213 already had a statistical significant effect on LDH level and necrotic RPEC, and the effect was proportional to the amount of neutrophils in the culture. Conclusion Both staphylococcus aureus exotoxins and neutrophils can damage the RPEC by inducing necrosis, and their function had synergetic effect.
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.
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 analyze the characteristics of distribution and drug resistance of clinical isolated staphylococci in the Whire Union Bacterial Resistance Surveillance Network across Sichuan from 2015 to 2018, so as to provide reference for clinical rational drug use and management of drug-resistant bacteria in Sichuan.MethodsA total of 18 023 strains of staphylococci were isolated from 9 hospitals of Whire Union Bacterial Resistance Surveillance Network for four years (2015-2018). Drug susceptibility test was carried out by disk diffusion method or automated instrument method. The data were statistically analyzed by WHONET 5.6 according to CLSI 2016 standard.ResultsThe 18 023 strains of staphylococci included 10 865 (60.28%) Staphylococcus aureus and 7 158 (39.72%) coagulase negative staphylococci. No strains resistant to vancomycin and linezolid were found. The detection rates of methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci were 25.10% (2 727/ 10 865) and 75.60% (5 411/7 158), respectively. The sensitivity of methicillin-resistant staphylococci to most antibiotics was significantly lower than that of methicillin-sensitive strains (P<0.05). The susceptibility rate of staphylococci to some antibiotics was significantly different from 2015 to 2018(P<0.05). The susceptibility rates of Staphylococcus aureus from different samples to rifampicin, moxifloxacin, ciprofloxacin, levofloxacin, oxacillin and erythromycin were significantly different (P<0.05). The susceptibility rates of Staphylococcus aureus from different departments in different samples of sulfamethoxazole, rifampicin, moxifloxacin, ciprofloxacin, levofloxacin, oxacillin, gentamicin, tetracycline, clindamycin and erythromycin were significantly different (P<0.05).ConclusionsThe susceptibility of strains isolated from different periods, different specimens and departments to the same antimicrobial agents varies greatly. For the infection of staphylococci, we should use drugs under the guidance of drug susceptibility according to the source of samples, which can avoid the abuse of beta-lactam drugs. Strengthening the monitoring and control of drug-resistant bacteria can prevent or reduce the spread of drug-resistant bacteria.
Objective To validate the advantage of repairing bone defect by staphylococcus aureus injection carried in collagen membrane. Methods Twentyfour adult New Zealand rabbits were divided into two groups randomly. After the experimental model of standard bone defect had been made by operation, collagen membrane/staphylococcus aureus injection and staphylococcus aureus injection with the same quantity were transplanted in bone defect areas of the two groups respectively. The reconstructed tissues were observed by general method, X-ray, histology, and immunohistochemistry at 2nd、4th、6th、8th week respectively. Results The experimental group showed that new bone proliferated distinctly in bone defect areaand the proliferation lasted long, and no excessive connective tissue in defectarea. X-ray observation showed that there was continual callus growth in transplantation area in early stage and the distribution of new bones was even in the group. Histological observation showed that there were many new bone growth centers in bone defect area, trabecular bones were sequentially distributed, and mature bone replacement was complete. Immunohistochemical examination showed that bone morphogenetic protein (BMP) could be seen for a long time and BMP took up a large part in the new bone tissues. Conclusion Collagen membrane could prevent parenchyma from penetrating into bone defect area and provide room for new bone growth. As the carrier of staphylococcus, collagen membrane could reduce the overflow of staphylococcus and improve its curative effect as well.
Immunoadsorption with Staphylococcus protein A column is a blood purification therapy that eliminates pathogenic antibodies on the principle that Staphylococcus protein A can specifically bind to human immunoglobin G efficiently. At present, it has been safely applied to a variety of autoimmune diseases and organ transplantation rejection and other fields. It has been reported to have efficacy for a variety of immune diseases, comparable to traditional plasma exchange. This article provides a review of the application progress of this technology in different systemic diseases, providing a reference for selecting blood purification treatment modes for clinical treatment of related diseases.
OBJECTIVE: To investigate the ability of repairing bone defect with the compound of coralline hydroxyapatite porous (CHAP), fibrin sealant(FS) and staphylococcus aureus injection (SAI), and the feasibility to use the compounds as bone substitute material. METHODS: The animal model of bone defect was made on the bilateral radius of 54 New Zealand white rabbits, which were randomly divided into the experimental group(the defect was repaired with CHAP-FS-SAI), control group(with autograft) and blank control group(the defect was left unrepaired) with 18 rabbits in each group. The ability of bone defect repair was evaluated by gross observation, histopathological study, X-ray and biomechanical analysis 2, 4, 8 and 12 weeks after repair. RESULTS: (1) In the 2nd week, tight fibro-connection could be found between the implant and fracture site and there were many fibroblasts and capillary proliferation with many chondrocytes around CHAP in the experimental group, while only a few callus formed, and chondrocytes, osteoblast and osteoclast existed in the control group. (2) In experimental group and control group, a large quantity of callus was found 4 and 8 weeks; ossification of chondrocytes with weave bone formation were found 4 weeks and many osteocytes and weave bones and laminar bones were found 8 weeks. (3) In the 12th week, the complete ossification of implant with well bone remodeling, a large number of mature osteocytes and laminar were found in experimental group and control group, and CHAP still existed in the experimental group; the defect area filled with fibro-scar tissue and only many fibroblasts could be seen in blank control group. (4) X-ray findings were the following: In experimental and control groups, callus formation could be seen 2 weeks postoperatively, more callus formed 4 weeks, the bone defect area disappeared and CHAP scattered in the callus 8 weeks; the fracture line disappeared and medullary cavity became united (in control group); and in the 12th week, the cortex became continuous, the medullary cavity became united, and remodeling completed, while bone defect was not still united in blank control group. The maximal torque and torsional stiffness in the experimental group is higher than those in the control group 2 weeks (P lt; 0.05), but there was no significant difference (P gt; 0.05) between the two groups 4, 8, 12 weeks after repair. CONCLUSION: The compound of CHAP-FS-SAI has good biological compatibility, and it can be used for one kind of bone substitute material to repair the bone defect.
Objective To observe the inhibitory characteristics of silver nanoparticles (AgNP) on bacterial biofilms and investigate their inhibitory effect on biofilm formation on three common orthopedic biomaterials. Methods The minimal inhibitory concentration (MIC) and minimal biofilm inhibitory concentration (MBIC) of AgNP were determined by microplate dilution assay. Biofilms of Staphylococcus aureus (ATCC 25923) were cultured on three orthopedic biomaterials (titanium alloy, titanium oxide, and stainless steel) and intervened with AgNP at concentrations of 32, 16, 8, 4, 2 and 0 μg/mL to determine the MBICs on the three materials. The effects of AgNP on biofilm formation were analyzed by scanning electron microscopy and measuring optical density. Results The MIC and MBIC of AgNP in the microplate assay were both 16 μg/mL. The MBICs of AgNP on biofilm formation in titanium oxide, titanium alloy, and stainless steel were 16 μg/mL, 32 μg/mL, and 32 μg/mL, respectively. Among the three materials, the lowest optical density was observed on titanium oxide, while the highest was on titanium alloy. Conclusions AgNP has strong antibacterial biofilm characteristics and can prevent the formation of Staphylococcus aureus biofilm in vitro. Biofilm formation is most pronounced on titanium alloy, least on titanium oxide, and intermediate on stainless steel.
Objective To establish rabbit models of mixture-infectious endophthalmitis induced by exogenous Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Methods A total of 84 eyes of 42 New Zealand white albino rabbits were randomly divided into 4 groups. There were 21 eyes in each group. Rabbit eyes in group 1, 2, 3 and 4 received an intravitreal injection of 0.1 ml of mix bacterium (2times;104 CFU/ ml, including 103 S. aureus and 103 E. coli), S. aureus (104 CFU/ ml), E. coli (104 CFU/ml), and sterilized saline respectively. The eyes were examined by slit-lamp microscopy, ophthalmoscopy, A/B scan, electroretinography (ERG) and bacterial culture of vitreous humors at the timepoints of 6, 12, 24, 48 and 72 hours, and 4, 7, 10, 14 days after intravitreal injection. All eyeballs were then enucleated for histopathological examination. Results Various degrees of inflammatory reactions were presented in the 3 experimental groups after the injection, and the development trend of the disease was nearly the same. In group 1 active intraocular inflammation like anterior chamber exudates, started at 12 hours after injection (which was early than that in group 2 and 3), aggravated between 48 and 72 hours, alleviated slowly from 4 to 7 days, and was obviously better after 10 to 14 days while the corneal neovascularization and vitreous gray opacity begun to form. The bacterial culture was positive in group 1 (100％, 6 hours to 14 days after injection), group 2 (100%, 6 hours to 3 days after injection) and group 3 (100% from 6 hours to 7 days, and 67.67% at 14 days after injection). It was negative for group 2 (7 to 14 days after injection) and group 4 (6 hours to 14 days after injection). The amplitude of ERG b wave dissapeard in group 1 to 3, and decreased less than 30% in group 4 from the 48th hour after injection. Histopathological examination revealed that all intraocular structures infiltrated with inflammatory cells. Conclusion Complicated endophthalmitis rabbit models can be successfully established by intravitreal injection with S. aureus and E. coli.
