Group Of Gram-negative Bacteria Research Articles

Abstract 144: Breast Implant Infections After Reconstruction: Clinical Characteristics Associated With Specific Microorganisms

Purpose: Infection following implant-based breast reconstruction (IBR) remains a major cause of increased health care costs, morbidity and reconstruction failure. Rates of infection from 5% to 35% have been reported. While the microbiology of breast implant infections has been studied, however, associations of specific clinical variables with common pathogens are not well understood. The aim of this study is to identify clinical characteristics associated with specific microorganism in patients with breast implant infections, in order to better guide treatment and empirical antimicrobial therapy. Methods: We retrospectively reviewed all patients who underwent IBR performed at our institution from 2007 to 2017 to identify cases of implant infection. Surgical site infection (SSI) was defined using the Centers for Disease Control and Prevention criteria. Demographic characteristics, comorbidities, surgical data, clinical presentation, laboratory, and microbiology data were collected. Comparative analysis of continuous variables and categorical variables were performed using the Mann-Whitney-Wilcoxon and Fisher’s exact tests, respectively. A value of p < 0.05 was considered significant. Results: A total of 2153 patients underwent IBR during the study period, of which 198 met case definition for SSI. Implant removal was required in 140 (70%) and positive culture data were identified from 105 (75%) clinical samples. There were 30 (29%) infections with Gram positive bacteria (GPB) and 75 (71%) with Gram negative bacteria (GNB). Of the GPB, Staphylococcus spp. and Streptococcus spp. were most common, whereas Pseudomonas spp. and Serratia spp. were most common among the GNB. In the GNB infections, obesity and autoimmune diseases were more prevalent (46.8% vs 17.8%; p=0.003, 75% vs 25%; p=0.032, respectively). Radiation therapy and adjuvant chemotherapy were more common in the GPB infections (86.7% vs 64.4%; p=0.027, 89.7% vs 63.3%; p=0.009, respectively). Compared to GPB, patients with GNB infections were more likely to present within 30 days after surgery (55% vs 15%; p=0.001). Erythema on exam was more commonly reported in those with GPB (76.1% vs 50%; p=0.047) whereas wound drainage (46.7% vs 18.2%; p=0.005) and necrosis (66.7% vs 23%; p=0.006) were more frequent in GNB infections. In GPB infections the median white blood cell count was 10.5 x 1000/mm3 vs. 7 x 1000/mm3 in the GNB group; p=0.004. Conclusion: Patients with GNB infections after IBR presented earlier and were more likely to present with wound drainage and necrosis of the skin compared to GPB infections. In contrast, infections caused by GPB were more likely to present with breast erythema and higher white cell counts. These clinical characteristics should be considered when selecting empiric antimicrobial therapy in IBR infections.

Clinical Presentation, Management, and Outcomes of Cardiovascular Implantable Electronic Device Infections Due to Gram-Negative Versus Gram-Positive Bacteria

ObjectiveTo describe and compare the clinical presentation, management, and outcomes of cardiovascular implantable electronic device (CIED) infections due to gram-negative bacteria (GNB) and CIED infections due to gram-positive bacteria (GPB). Patients and MethodsWe retrospectively reviewed all CIED infection cases at Mayo Clinic from January 1, 1992, through December 31, 2015. Cases were classified based on positive microbiology data from extracted devices or blood cultures. ResultsOf the 623 CIED infections during the study period, 31 (5.0%) were caused by GNB and 323 (51.8%) by GPB. Patients in the GNB group were more likely to present with local inflammatory findings at the pocket site (90.3% vs 72.4%; P=.03). All patients with bacteremia due to GNB had concomitant pocket infection compared with those with GPB (100% vs 33.9%; P=.002). After extraction, 41.9% of patients in the GNB group were managed with oral antibiotics vs 2.4% in the GPB group (P<.001). There were no statistically significant differences in infection relapse/recurrence or 1-year survival rates between the 2 groups. ConclusionCompared with CIED infections caused by GPB, those due to GNB are more likely to present with pocket infection. Device-related GNB bacteremia almost always originates from the generator pocket. After extraction, oral antibiotic drug therapy may be a reasonable option in select cases of pocket infections due to GNB. No difference in outcomes was observed between the 2 groups.

Bio-synthesis and antimicrobial activity of silver nanoparticles using anaerobically digested parthenium slurry

Silver nanoparticles were prepared through eco-friendly, cost effective, bio-mediated technique using anaerobically digested Parthenium hysterophorous digested slurry (PDS) for the first time. The synthesized nanoparticles were characterized through different techniques such as UV–Vis spectrophotometer for optical properties; X-ray diffractometer (XRD), high resolution transmission electron spectroscopy (HR-TEM) and Fourier Transform Infra Red (FTIR) Spectroscopy for structural property investigations. It was observed that the prepared silver nanoparticles were crystallized in face centered cubic crystal structure with an average particle size of 19 nm as confirmed from XRD. Also HR-TEM studies reveal the formation of nano-sized silver particles with face centered cubic nano structure. In addition, absorption spectra exhibit Surface Plasmon Resonance (SPR) which suggests the formation of silver nanoparticles. FTIR results show the presence of different characteristic functional groups and their stretching / bending vibrations in turn responsible for the bioreduction of silver ions in Parthenium digested slurry. Further investigations on antimicrobial activity were done by subjecting the synthesized silver nanoparticles on E-coli and Pseudomonas as marker organisms for the group of gram negative bacteria by well plate method on enrichment media. The result obtained shows a clear zone of inhibition confirming the antibacterial activity. Overall, the investigated results confirm the biosynthesized silver nanoparticles are potential candidates for antimicrobial activity applications.

Chemometric Analysis of Bacterial Peptidoglycan Reveals Atypical Modifications That Empower the Cell Wall against Predatory Enzymes and Fly Innate Immunity.

Peptidoglycan is a fundamental structure for most bacteria. It contributes to the cell morphology and provides cell wall integrity against environmental insults. While several studies have reported a significant degree of variability in the chemical composition and organization of peptidoglycan in the domain Bacteria, the real diversity of this polymer is far from fully explored. This work exploits rapid ultraperformance liquid chromatography and multivariate data analysis to uncover peptidoglycan chemical diversity in the Class Alphaproteobacteria, a group of Gram negative bacteria that are highly heterogeneous in terms of metabolism, morphology and life-styles. Indeed, chemometric analyses revealed novel peptidoglycan structures conserved in Acetobacteria: amidation at the α-(l)-carboxyl of meso-diaminopimelic acid and the presence of muropeptides cross-linked by (1-3) l-Ala-d-(meso)-diaminopimelate cross-links. Both structures are growth-controlled modifications that influence sensitivity to Type VI secretion system peptidoglycan endopeptidases and recognition by the Drosophila innate immune system, suggesting relevant roles in the environmental adaptability of these bacteria. Collectively our findings demonstrate the discriminative power of chemometric tools on large cell wall-chromatographic data sets to discover novel peptidoglycan structural properties in bacteria.

Synthesis, Structural Elucidation and Anti-Bacterial Evaluation of Some Novel Heterocyclic Molecules Derived from Thieno [2,3-d] Pyrimidine as a Core Unit

A series of novel 4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-substituted phenyl/Heterocyclic Thieno[2,3-d] Pyrimidine (8 a-j) derivatives were synthesized by a facile Five-step procedure that afforded advantages of mild reaction conditions, simple protocol and good yields. The structures of the final compounds were confirmed by IR, NMR, EI-MS. The final compounds were screened for their anti-bacterial activity against Bacillus subtilis and Staphylocouccus aureus from Gram positive group of bacteria and Escherichia coli and Klebsiella pneumonia from Gram negative group of bacteria and antifungal activity against Candida albicans and Aspergillus flavus. Anti-bacterial and anti-fungal activities were Evaluated and compared with the standard drugs Such as Amoxicillin and Ketoconazole. From anti-bacterial and antifungal activity screening results, it has been observed that compounds 8i, 8h, 8e and 8j possess good activity.

Synthesis, Structural Elucidation of Novel Thieno [2,3-d] Pyrimidine Core Unit Containing 1,2,4-Triazoles and Thiophenes as Potent Antimicrobial Activity

Several new thieno[2,3-d] Pyrimidine derivatives 3-Substituted phenyl-5-(thiophen-2-yl) thieno[3,2-e] [1,2,4] triazolo[4,3-c] pyrimidine 7(a-j), were synthesized starting from thieno[2,3-d] pyrimidine-2,4-diol (1). The characterization of the newly synthesized compounds was established by IR, 1H NMR, 13C NMR and Mass Spectral analysis. The final compounds were screened for their anti-bacterial activity against Bacillus subtilis and Staphylocouccus aureus from Gram positive group of bacteria and Escherichia coli and Klebsiella pneumonia from Gram negative group of bacteria and antifungal activity against Candida albicans and Aspergillus flavus. Antibacterial and anti-fungal activities were Evaluated and compared with the standard drugs. From anti-bacterial and anti-fungal activity screening results, it has been observed that compounds 8i, 8j, 8e possess good activity.

Comparison of the Incidence and Clinical Characteristics of Gram-positive and Gram-negative Surgical Site Infections after Gastric Surgery

Background: Surgical site infection (SSI) is prominent among the total incidence of healthcare-associated infections, and is a major contributing factor in the trend of increasing medical costs. There have been numerous efforts to analyze the conditions and causes of SSI for the purpose of prevention. In this study of SSI development after gastric surgery, we evaluated the prevalence of specific pathogens and compared the clinical characteristics observed between gram-positive (GPB)and gram-negative bacteria (GNB). Materials and Methods: We conducted a retrospective study of patients who developed SSI within 30 days after gastric surgery at 13 clinics in Korea, between January 2007 and December 2008. Only those cases of SSI which included confirmed pathogen were included in this study. Results: Among the 121 patients who developed SSI, GPB were observed in 32 patients and 36 cases, and GNB were isolated in 32 patients and 36 cases. Methicillin resistant Staphylococcus aureus (MRSA) was the most frequently isolated pathogen in this analysis. There were no differences observed between the GPB and GNB group in terms of baseline characteristics, patient or procedure related risk factors, or factors associated with prophylactic antibiotics. Conclusions: In the previous studies of the occurrence of SSI after gastric surgery,it was reported that the majority of observed pathogens were enteric GNB. Further studies of the incidence of SSI after gastric surgery, particularly those related to MRSA infection, are necessary.

The effect of Quercus castaneifolia extract on pathogenic enteric bacteria

The family of Enterobacteriaceae is a major group of gram negative bacteria, some of these microorganisms are pathogen and could cause disease mainly gastroenteritis. Recently, due to drug resistant nature of these bacteria specially in developing countries treatment of the patient considered as important investigate. Quercus castaneifolia is a native plant of Yasuj province in Iran, which the people who living in this area consume the fruit of this plant for treatment of enteric disease. Hence, the present study was conducted to evaluate the effect of fruit of Q. castaneifolia extract on pathogenic enteric bacteria viz., E. coli, Salmonella typhimurium, Shigella dysenteriae and Yersinia enterocolitica. Antimicrobial susceptibility and minimal inhibitory concentration (MIC) of the extracts were assessed by gel diffusion method and modification of E-test respectively. All the experiments were performed in triplicate and the statistical analysis was carried out on the results. The results obtained from this study indicated that alcoholic extract was shown antimicrobial effect on the microorganisms tested. In addition, S. dysentriae was more sensitive with zone of inhibition 18 mm and MIC value was 2.5 × 10 −4 whereas, E. coli was less sensitive with zone of inhibition 12 mm and MIC value 1 × 10 −2. Salmonella typhimurium and Yersinia enterocolitica showed relatively intermediate susceptibility to the extract with zone of inhibition of 14 mm and MIC value 5 × 10 −3. Overall, Q. castaneifolia may be considered for treatment of the patients suffering from enteric disease.

The autotransporter protein from Bordetella avium, Baa1, is involved in host cell attachment

Bordetella avium is a Gram negative upper respiratory tract pathogen of birds. B. avium infection of commercially raised turkeys is an agriculturally significant problem. Here we describe the functional analysis of the first characterized B. avium autotransporter protein, Baa1. Autotransporters comprise a large family of proteins found in all groups of Gram negative bacteria. Although not unique to pathogenic bacteria, autotransporters have been shown to perform a variety of functions implicated in virulence. To test the hypothesis that Baa1 is a B. avium virulence factor, unmarked baa1 deletion mutants (Δ baa1) were created and tested phenotypically. It was found that baa1 mutants have wild-type levels of serum sensitivity and infectivity, yet significantly lower levels of turkey tracheal cell attachment in vitro. Likewise, semi-purified recombinant His-tagged Baa1, expressed in Escherichia coli, was shown to bind specifically to turkey tracheal cells via western blot analysis. Taken together, we conclude that Baa1 acts as a host cell attachment factor and thus plays a role B. avium virulence.

The clinical application of leukocyte VCS parameters in the detection of blood bacterial infection

Objective To investigate the clinical application of VCS parameters of leukocyte in the detection of blood bacterial infection, Methods The subjects consisted of 120 patients with blood bacterial infection,69 non-infectious fever patients and 67 health controls.The VCS parameters of neutrophil and lymphocyte were examined with Coulter LH 750 hematology analyzer.The parameters examined including mean channel of neutrophil volume(MNV),neutrophil volume distribution width (NDW) ,mean channel of neutrophil conductivity (MNC),mean channel of neutrophil scatter (MNS),mean channel of lymphocyte volme(MLV),lymphocyte volume distfibufion width (LDW),mean channel of lymphocyte conductivity (MLC) and mean channel of lymphocyte scatter (MLS).Additionally,120 blood bacterial infection patients were grouped according to WBC count(WBC≤10×109/L group and WBC＞10×109/L group),neutrophii rate(≥85%group and＜85%group)and bacterial stain(Gram positive bacteria group and Gram negative bacteria group).VCS parameters among these groups were compared.Results The results of blood infection group were as follows:MNV 156±15,NDW 23.31±3.72,MNS 137±7,MLV 87±12,LDW 17.50±3.38.MLC 110±5 and MLS 69±12.The results of non-infectious fever group were as follows:MNV 151±8,NDW 21.33 ±2.62,MNS 132±10,MLV 91±4.LDW 15.78±1.96.MLC 117±4 and MLS 62±6.The results of control group were as follows:MNV145 ±5.NDW 18.43±0.93.MNS 143 ±4,MLV 84±2,LDW 13.30±0.76.MLC 108±1 and MLS 62±2.There were significant diffierences among these three groups (F value were 19.295,26.272,32.767,6.226,31.016,23.739 and 12.662 respectively,P＜0.05 or P＜0.01).In the infection group.the MNV and NDW were 152 ±16 and 22.19±3.45 respectively for WBC≤10×109/L group.159±12 and 25.29±3.43 respectively for WBC＞10×109/L group.They were both significantly different compared with control group (F valRe were 21.575 and 40.856 respectively,P＜0.01).Also in the infection group.the MNV and NDW were 159±12 and 24.88 ±3.74 respectively for neutrophil rate≥85%group.151±16 and 21.68±2.29 respectively for neutrophil rate＜85%group.They were both significantly different compared with control group(F value were 23.76 and 43.22 respectively,P＜0.01).The MNV and NDW were 157±15 and 24.25±3.39 respectively in those cases with gram-negative bacteremia,153±14 and 21.51±3.78 respectively in those cases with gram-positive bacteremia.They were both signifieanfly difierent compared with control group (F value were 18.74 and 37.47 respectively,P＜0.01).With a cut-off value of 20.50 for the NDW,a sensitivity of 76.7%and specificity of 98.3% were achieyed in diagnosing blood hacterial infection.Conclusion The VCS parameters can reflect the morphologic change of leukocyte in blood bacterial infection.Additionally.the NDW can detect blood bacterial infection more sensitively and specifically. Key words: Bacterial infections; Leukocyte count

MPV007 Molecular analysis of transport and oligomerization of the Yersinia enterocolitica adhesin YadA

Bordetella avium is a Gram negative upper respiratory tract pathogen of birds. B. avium infection of commercially raised turkeys is an agriculturally significant problem. Here we describe the functional analysis of the first characterized B. avium autotransporter protein, Baa1. Autotransporters comprise a large family of proteins found in all groups of Gram negative bacteria. Although not unique to pathogenic bacteria, autotransporters have been shown to perform a variety of functions implicated in virulence. To test the hypothesis that Baa1 is a B. avium virulence factor, unmarked baa1 deletion mutants (Δbaa1) were created and tested phenotypically. It was found that baa1 mutants have wild-type levels of serum sensitivity and infectivity, yet significantly lower levels of turkey tracheal cell attachment in vitro. Likewise, semi-purified recombinant His-tagged Baa1, expressed in Escherichia coli, was shown to bind specifically to turkey tracheal cells via western blot analysis. Taken together, we conclude that Baa1 acts as a host cell attachment factor and thus plays a role B. avium virulence.

Some properties of the nonsporing anaerobes from poultry caeca.

Summary: A study has been made of the ability of 48 strains of anaerobic bacteria, representing 20 different groups of Gram negative and Gram positive nonsporing rods and peptostreptococci, isolated from poultry caeca, to attack certain substrates that may be of ecological importance. The organisms were predominantly saccharolytic; only the strains of Propionibacterium acnes showed proteolytic activity. None of the strains hydrolysed amorphous cellulose or xylan. A few were weakly pectolytic. Starch was hydrolysed by all the strains of Bacteroides fragilis and by one strain of Eubacterium. Two groups of Gram negative bacteria (Bacteroidaceae) and one of the peptostreptococci attacked uric acid. The resistance of the anaerobes to inhibitory substances (bacitracin, virginiamycin, kanamycin, neomycin, vancomycin and nalidixic acid) was determined. Selective media for the isolation of certain of the groups of Gram negative anaerobes have been developed.

Symposium on microbial changes in foods. Bacteria active in the spoilage of certain sea foods.

Summary.Spoilage of certain sea foods is caused by the activities of some groups of Gram negative bacteria. The characteristic off odours and flavours of naturally spoiling cod and haddock have been reproduced in blocks of sterile cod muscle by organisms identified as Pseudomonas putida, Ps. fragi, Ps. putrefaciens and other Pseudomonas spp.