Proportion Of Gram-negative Bacteria Research Articles

Gut Microbiome Dysbiosis in Patients with Pemphigus and Correlation with Pathogenic Autoantibodies.

Pemphigus is a group of potentially life-threatening autoimmune bullous diseases induced by pathogenic autoantibodies binding to the surface of epidermal cells. The role of the gut microbiota (GM) has been described in various autoimmune diseases. However, the impact of the GM on pemphigus is less understood. This study aimed to investigate whether there was alterations in the composition and function of the GM in pemphigus patients compared to healthy controls (HCs). Fecal samples were collected from 20 patients with active pemphigus (AP), 11 patients with remission pemphigus (PR), and 47 HCs. To sequence the fecal samples, 16S rRNA was applied, and bioinformatic analyses were performed. We found differences in the abundance of certain bacterial taxa among the three groups. At the family level, the abundance of Prevotellaceae and Coriobacteriaceae positively correlated with pathogenic autoantibodies. At the genus level, the abundance of Klebsiella, Akkermansia, Bifidobacterium, Collinsella, Gemmiger, and Prevotella positively correlated with pathogenic autoantibodies. Meanwhile, the abundance of Veillonella and Clostridium_XlVa negatively correlated with pathogenic autoantibodies. A BugBase analysis revealed that the sum of potentially pathogenic bacteria was elevated in the AP group in comparison to the PR group. Additionally, the proportion of Gram-negative bacteria in the PR group was statistically significantly lower in comparison to the HC group. The differences in GM composition among the three groups, and the correlation between certain bacterial taxa and pathogenic autoantibodies of pemphigus, support a linkage between the GM and pemphigus.

Predisposing factors, clinical and microbiological insights of bacterial keratitis: analysis of 354 cases from a leading French academic centre

AimsTo report an epidemiological update of bacterial keratitis (BK) in a tertiary ophthalmology centre over 20 months compared with a previous study on the same timeframe from 1998 to 1999.Methods354...

Distribution and antimicrobial resistance patterns of urinary pathogens in preoperative midstream urine cultures from Chinese patients with urinary calculi: a meta-analysis.

This study comprehensively evaluates the distribution patterns and antimicrobial resistance profiles of urinary pathogens in Preoperative midstream urine cultures collected from patients with urinary calculi in China over the last two decades. A cross-sectional analysis of 41 studies was conducted. A systematic search across various databases, including Wanfang Data, CNKI, SinoMed, Embase, PubMed, and Web of Science, was carried out, covering the time period from 2002 to 2022. Using R 4.2.1 software, a meta-analysis was performed to assess heterogeneity using Cochran's Q test and the I2 statistic. In the analysis of preoperative midstream urine cultures from Chinese patients with urinary calculi, gram-negative bacteria dominated at 69%, with Escherichia coli (43%), Klebsiella pneumoniae (8%), Proteus mirabilis (6%), Pseudomonas aeruginosa (5%), Acinetobacter baumannii (3%), and Enterobacter cloacae (4%) being prominent. Gram-positive organisms included Enterococcus faecalis (9%), Enterococcus faecium (5%), and Staphylococcus aureus (4%). Over time, proportions of Proteus mirabilis, Enterococcus faecalis, and Staphylococcus aureus decreased, while Klebsiella pneumoniae and Pseudomonas aeruginosa increased. Notably, Escherichia coli proportion reduced from 37 to 33% within the last two decades. Antimicrobial resistance analysis indicated declining resistance in E. coli (e.g., co-trimoxazole from 73 to 55%, gentamicin from 64 to 40%), but rising resistance in piperacillin and cefotaxime (34-60%). Enterococcus faecalis exhibited increasing resistance to ampicillin (5-69%), gentamicin (59-94%), and tetracycline (77-89%) over time, while resistance to levofloxacin and ciprofloxacin notably decreased (72-16% and 49-8%, respectively). Over the past two decades, the proportion of gram-negative bacteria was declined, while the proportion of gram-positive bacteria increased. Escherichia coli remained the most common pathogen in the urine culture of patients with urinary calculi in China and the resistance of Escherichia coli to commonly used antibiotics increased. Clinicians should select appropriate antibiotics according to the results of urine culture and drug sensitivity test to reduce the occurrence of antibiotic resistance.

Compositional alterations of the gut microbiota in acute myocardial infarction patients with type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is a risk factor for acute myocardial infarction (AMI) and a common comorbidity in patients with AMI. T2DM doubles the fatality rate of patients with AMI in the acute phase of AMI and the follow-up period. However, the mechanisms by which T2DM increases the fatality rate remain unknown. This study sought to investigate changes in the gut microbiota of patients with AMI and T2DM (AMIDM) to extend understandings of the relative mechanisms from the aspects of gut microbiota. Patients were recruited and divided into 2 groups comprising 15 patients with AMIDM and 15 patients with AMI but without T2DM (AMINDM). Their stool samples and clinical information were collected. 16S ribosomal DNA sequencing was used to analyze the structure and composition of the gut microbiota based on the operational taxonomic units. A significant difference was observed in the gut microbiota β diversity between the 2 groups. At the phylum level, the AMIDM patients showed an increase in the abundance of Firmicutes and a decrease in the abundance of Bacteroidetes compared to the AMINDM patients. At the genus level, the AMIDM patients showed an increase in the abundance of Companilactobacillus, Defluvitaleaceae UCG-011 and UCG-009, and a decrease in the abundance of Phascolarctobacterium and CAG 56 compared to the AMINDM patients. At the species level, the AMIDM patients showed an increase in the abundance of species unclassified NK4A214 group, Bacteroides clarus, Coprococcus comes, unclassified Defluviltaleaceae UCG-011, uncultured rumen bacterium, unclassified CAG 56, Barnesiella intestinihominis, Lachnospiraceae bacterium, Bacteroides nordii, unclassified UCG-009, and the Family XIII AD3011 group compared to the AMINDM patients. The gut microbiota function predictions indicated that the nucleotide metabolism-related pathway was significantly more increase in the patients with AMIDM than those with AMINDM. Additionally, the patients with AMIDM showed an increase in gram-positive bacteria and a decrease in the proportion of gram-negative bacteria. Our correlation analysis results on the gut microbiota and clinical parameters might extend understandings of the progression of AMI. Changes in the gut microbiota composition of patients with AMIDM affect the severity of the metabolic disturbance and may be responsible for poorer clinical outcomes and worse disease progression in patients with AMIDM compared to those with AMINDM.

Gram-Negative Bacteria and Lipopolysaccharides as Risk Factors for the Occurrence of Diabetic Foot.

Imbalance of the skin microbial community could impair skin immune homeostasis and thus trigger skin lesions. Dysbiosis of skin microbiome may be involved in the early pathogenesis of diabetic foot (DF). However, the potential mechanism remains unclear. To investigate the dynamic composition and function of the foot skin microbiome with risk stratification for DF and assess whether dysbiosis of the skin microbiome induces diabetic skin lesions. We enrolled 90 consecutive subjects who were divided into 5 groups based on DF risk stratification: very low, low, moderate, and high risk for ulcers and a healthy control group. Integrated analysis of 16S ribosomal RNA and metagenomic sequencing of cotton swab samples was applied to identify the foot skin microbiome composition and functions in subjects. Then a mouse model of microbiota transplantation was used to evaluate the effects of the skin microbiome on diabetic skin lesions. The results demonstrated that, with the progression of diabetic complications, the proportion of gram-negative bacteria in plantar skin increased. At the species level, metagenome sequencing analyses showed Moraxella osloensis to be a representative core strain in the high-risk group. The major microbial metabolites affecting diabetic skin lesions were increased amino acid metabolites, and antibiotic resistance genes in microorganisms were abundant. Skin microbiota from high-risk patients induced more inflammatory cell infiltration, similar to the lipopolysaccharide (LPS)-stimulated response, which was inhibited by Toll-like receptor 4 (TLR4) antagonists. The skin microbiome in patients with diabetes undergoes dynamic changes at taxonomic and functional levels with the progression of diabetic complications. The increase in gram-negative bacteria on the skin surface through LPS-TLR4 signal transduction could induce inflammatory response in early diabetic skin lesions.

Does the Microflora of Surgery Site Infection Change After Prophylactic Use of Vancomycin Powder in the Spine Surgery

Retrospective cohort study. This study aimed to investigate the characteristics of microflora in patients with deep spinal surgical site infection (SSI) after prophylactic use of vancomycin powder (VP). A retrospective analysis was performed on patients after spinal surgery. Patients were grouped according to whether VP use and only patients with deep SSI were included in this study. General information of the patients, the dose of vancomycin, bacterial culture results, drug sensitivity test results, and SSI treatment methods were recorded. The differences of microflora between the two groups were analyzed, and the sensitivity of bacteria in the +VP group to antibiotics was analyzed. The infection rate in the +VP group was 4.9% (56/1124) vs 6.3% (93/1476) in the No-VP group (P < 0.05). The proportion of Gram-positive bacteria (GPB) in the +VP SSIs was 55.4% vs.74.1% in the No-VP group (P < 0.05). The percentage of Gram-negative bacteria (GNB) in the +VP SSIs was 46.4% vs.30.1% in the No-VP group (P < 0.05). More dose of VP cannot decrease the SSI, but the proportion of GNB in VP >1g SSIs was higher (59.0% vs 32.4%, P < 0.05). In the +VP SSIs, all of the GNB cultured were sensitive to meropenem, and linezolid covered most of the GPB cultured. Local use of vancomycin powder can reduce the incidence of SSI, but this may lead to changes in the bacterial flora. Once the SSI occurs, the case of GNB infection may be increased. The more dose of VP cannot decrease SSI but may increase the rate of GNB in the +VP SSIs. Once infections still occur after VP use, antibiotics covering GNB may be added. These findings may help guide choice of empiric antibiotics while awaiting culture data.

Seasonal dynamics in bacterial communities of closed-cage broiler houses.

The bacteria contained in air aerosols from poultry houses are closely connected to animal health and production. This study aimed to investigate the seasonal factors on microbial aerosol concentration, particle size and bacterial spectrum composition inside a closed-cage broiler house. Then, 16S rDNA sequencing technology was applied to analyze the characteristics of bacterial abundance and diversity. The results indicated that the concentration of bacterial aerosol in the broiler house varied significantly in different seasons, with a concentration range of 5.87-15.77 × 103 CFU/m3, and the highest and lowest concentrations in the summer and winter, respectively. Microbiological analysis showed that the proportion of Gram-negative bacteria in autumn was significantly higher than that in summer (P < 0.05). In addition, the floral structure of potential pathogenic bacterial genera also differed by season. Escherichia-Shigella, Streptococcus, Acinetobacter, Pseudomonas were identified in the bacterial aerosols. Importantly, the relative abundance of Firmicutes in spring and autumn was much higher. In contrast, the relative abundance of Proteobacteria in spring and autumn was lower than that in summer and winter. Altogether, results revealed the effects of seasonal factors on the diversity and abundance of bacteria and the distribution characteristics of major opportunistic pathogens in the air of closed-cage broiler houses. These results will provide important information for exploring the potential risk of aerosols from poultry houses all four seasons.

Comparative Analysis of Bacterial Microflora Isolated from Adult Pneumonia Inpatients and Hospital Objects in the Amur Region

Background: The COVID-19 pandemic has exacerbated the problem of healthcare-associated infections and worsened the situation with the hospital spread of antibiotic resistant strains potentially inducing nosocomial infections. Objective: To compare bacterial microflora isolated from adult pneumonia inpatients and hospital objects and to assess the risk of hospital-acquired infections in the Amur Region. Materials and methods: The study was conducted in a multidisciplinary and a “COVID” hospital hereinafter referred to as Hospitals 1 and 2, respectively. Parallel bacteria culture testing of 519 sputum samples from 284 inpatients and 486 wipe samples collected weekly during 12 weeks in both hospitals was carried out using a classical method. AutoSCAN-4 and Vitek® 2 Compact 30 analyzers were applied to identify pathogens and determine their antimicrobial susceptibility. Results: Along with the detection of pathogenic bacteria in 33.8 % of hospitalized patients with pneumonia, we found pathogens in 23.3 % and 12.4 % of wipe samples from Hospitals 1 and 2, respectively, and established that the proportion of Gram-negative bacteria in them was 44.9 % and 15.4 % while the share of multidrug-resistant strains was 32.7 % and 3.8 %. The significant differences observed can be attributed to a more stringent disinfection regime in Hospital 2. The structure of multidrug-resistant Gram-negative bacteria was noted for a high proportion of carbapenem-resistant organisms isolated from both sputum (20.0 %) and wipe (38.9 %) samples. Conclusion: Our monitoring results helped define the composition and ratio of bacterial pathogens isolated from pneumonia cases and hospital objects. A wide range of pathogens, including those resistant to antibiotics, often detected in wipe samples and their accumulation over time indicate the potential hazard of the hospital environment posing an increased risk of hospital-acquired infections.

Environmental exposure to swine farms reshapes human gut microbiota

The gut microbiota can change to varying degrees because of changes in the environment. In the present study, we performed microbial amplicon sequencing on the feces of people who had long-term exposure to swine farms (F) and that of people living in normal environments (S) to investigate the impact of the environment on the human gut microbiota. A total of 1,283,503 high-quality ordered sequences were obtained, which provided different levels of microbial classification and statistics. We found that different environments did not alter the richness and diversity of the microbial communities in participants, but caused significant changes in the proportion of some bacteria. The main bacterial phyla found in group F participants were Firmicutes (69.44–89.03%), Actinobacteria (1.7–18.95%), and Bacteroidetes (1.17–22.35%); those found in group S participants were Firmicutes (49.93–95.04%), Bacteroidetes (0.62–39.59%), and Proteobacteria (0.98–11.95%). Additionally, because of changes in phylum proportions, the Bugbase phenotypic classification predicted an increase in the proportion of Gram-positive bacteria in group F and an increase in the proportion of Gram-negative bacteria in group S. In conclusion, our findings suggest that human exposure to swine farms can reshape the gut microbiota, resulting in changes in the microbial abundances. This change can potentially reduce the odds of developing bowel disease and contribute to the prevention of intestinal diseases, providing a theoretical basis for improving human health.

P1604: DISTRIBUTION AND ANTIBIOTIC RESISTANCE PROFILE OF PATHOGENIC MICROORGANISMS CAUSING NOSOCOMIAL INFECTION IN PATIENTS UNDERGOING HEMATOPOIETIC STEM CELL TRANSPLANTATION

Background: In recent years, with the wide use of antibiotics and extensive invasive procedures, the drug resistance of bacteria causing nosocomial infection is becoming more and more serious. Due to the characteristics of hematopoietic stem cell transplantation patients and the use of large doses of chemotherapeutic drugs, a variety of immunosuppressants and a large number of broad-spectrum antibiotics, the immune function of patients is very low. As a result, the infection rate of hematopoietic stem cell transplantation patients in hospital is rising and new drug-resistant strains are emerging, which poses a great challenge to the control of nosocomial infection. Aims: To approach the distribution and antibiotic resistance profile of pathogenic microorganisms causing bloodstream infection in patients undergoing hematopoietic stem cell transplantation, so as to provide evidences for rational clinical use of antibiotics. Methods: The clinical data, including the types of pathogenic microorganisms and their resistance profile to commonly used antibiotics, of patients developing bloodstream infection during hematopoietic stem cell transplantation from January 2020 to December 2021 were analyzed retrospectively. Results: A total of 68 pathogenic strains were isolated from 405 patients undergoing hematopoietic stem cell transplantation, including 24 (35.3%) Gram-positive strains, primarily Staphylococcus and Enterococcus; 42 (61.8%) Gram-negative strains, primarily Escherichia coli and Klebsiella pneumoniae; and 2 (2.9%) fungus strains which were both Trichosporon asahii. Escherichia coli had the highest resistance rate (100%) to piperacillin, cotrimoxazole, and ampicillin, and the highest susceptibility rate (100%) to tigecycline, amikacin, imipenem, and meropenem. Klebsiella pneumoniae had the highest resistance rate (100%) to ampicillin, and the highest susceptibility rate (0) to tigecycline. The primary Gram-positive bacteria were 100% susceptible to teicoplanin, quinupristin/dafopentine, rifampicin, vancomycin, linezolid, nitrofurantoin, and amikacin; vancomycin-resistant enterococci (VRE) were not identified. Trichosporon asahii was 100% susceptible to amphotericin B, nystatin, caspofungin, and voriconazole. Summary/Conclusion: There are various pathogenic microorganisms that could cause bloodstream infection in patients undergoing hematopoietic stem cell transplantation, with high multi-drug resistance rate. The proportion of Gram-negative bacteria is increasing. During hematopoietic stem cell transplantation, it is expected to strengthen monitoring of the pathogenic microorganisms, so as to provide effective prevention to control infection with the pathogenic microorganisms, thus improving the patients’ survival rate.

Clinical characteristics of external bacterial ocular and periocular infections and their antimicrobial treatment patterns among a Ghanaian ophthalmic population

Empirical antimicrobial therapy is linked to a surge in antimicrobial resistant infections. However, an insight on the bacteria etiology of ocular infections is essential in the appropriation of choice of antimicrobial among clinicians, yet there remains a dearth of data from Ghana. We investigated the bacteria etiology of external ocular and periocular infections and antimicrobial treatment patterns among a Ghanaian ophthalmic population. A multicenter study design with purposive sampling approach was employed. Patients demographics and clinical data were collated using a pretested structure questionnaire. Cornea specimens and conjunctival swabs were obtained for bacterial isolation following standard protocols. About 95% (98/103) of ocular samples were positive for bacteria culture. The proportion of Gram-negative bacteria was 58.2%, and the predominant bacteria species were Pseudomonas aeruginosa 38.8% and Staphylococcus aureus 27.6%. Conjunctivitis 40.0% and keratitis 75.0% were mostly caused by Pseudomonas aeruginosa. The routinely administered antimicrobial therapy were polymyxin B 41.2%, neomycin 35.1% and ciprofloxacin 31.6%. Participants demographic and clinical characteristics were unrelated with positive bacteria culture (p > 0.05). Our results showed a markedly high burden of ocular bacterial infections and variations in etiology. Bacterial infection-control and antimicrobial agent management programs should be urgently institutionalized to prevent the emergence of resistant infections.

Abstract 3141: Toll-like receptor 4 knockout promotes cutaneous tumorigenesis in mice lack of Ikka heterozygous loss in keratinocytes

Abstract Role of recognizing pathogen-associated molecular patterns in skin carcinogenesis has not been extensively studied. Toll-like receptor 4 (TLR4) recognizes gram-negative lipopolysaccharide. To explore the impact of interplay between TLR4-regulated microbiota and host epithelial cells on tumorigenesis, we adopted a mouse model that expresses hemizygous Ikkα gene induced by a keratin 5 Cre (K5.Cre, IkkααKC/+). IkkααKC mice die within 3 weeks after birth. Inducible Ikkα ablation mediated by K15.CrePR1 or K5.CreER results in spontaneous skin tumors. We found an increased incidence of spontaneous skin tumors in Tlr4-/-;IkkααKC/+ mice compared to Tlr4-/- or IkkααKC/+ mice. We detected markedly elevated bacteria numbers on the surface of skin tumors compared to the adjacent skin. Interestingly, the oral cavity of Tlr4-/-;IkkααKC/+ mice showed an elevated proportion of gram-negative bacteria compared to Tlr4-/- or IkkααKC/+ mice. To further determine the effect of bone marrow (BM)-derived hemopoietic cells on tumorigenesis, we performed BM transplant experiments. IkkααKC/+ mice with Tlr4-/- BM developed more cutaneous skin tumors than IkkααKC/+ mice with WT BM. Based on these findings, we hypothesized that Tlr4-/- hemopoietic cells regulate microbiota, which further results in altered skin carcinogenesis. We are revealing the detailed mechanism of how Tlr4-/- hemopoietic cells contribute to microbiota changes and tumorigenic promotion. Citation Format: Amit Kumar Singh. Toll-like receptor 4 knockout promotes cutaneous tumorigenesis in mice lack of Ikka heterozygous loss in keratinocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3141.

THE FREQUENCY AND MICROBIOLOGICAL CHARACTERISTICS OF BACTERIA CAUSING SEPTIC SHOCK AT NGHE AN GENERAL FRIENDSHIP HOSPITAL

Abstract: Objectives: To determine the frequency and microbiological characteristics of bacteria causing septic shock in patients with positive blood culture results. Methods: Cross-sectional descriptive study. Results: Total 100 patients diagnosed with septic shock had positive blood culture results at Nghe An General Friendship Hospital from January 2020 to December 2020. The mean age was 67.06 ± 16.42 years old. There were 57 patients ≥ 65 years old, accounting for 57%, more common than patients &lt; 65 years old (43 patients with a rate of 43%). The proportion of Gram-negative bacteria (66%) was higher than Grampositive bacteria (34%). The respiratory tract infection (52%) was the most common source, followed by the intra-abdominal infection (23%) and the urinary tract infection (10%). E. coli was the most common pathogen (32%), followed by S. aureus (26%) and K. pneumoniae (11%). Among patients with diabetes and COPD, the most common pathogens were E. coli, S. aureus and Enterococcus faecalis. Most of the antibiotic groups were been resistant, especially cephalosporin antibiotics from 37.5% to 82.6%. Amikacin, fosmycin, vancomycin and linezolid groups were susceptible to bacteria. Conclusion: E. coli and S. aureus were two common pathogens in patients with septic shock. In particular, E. coli, S. aureus and Enterococcus faecalis were the common agents of septic shock among patients with diabetes and COPD. Amikacin, Fosmycin, Vancomycin and Linezolid groups were still susceptible to bacteria. Key words: septic shock, E. coli, S. aureus.

Bacteriological Investigation and Drug Resistance Analysis of Chronic Refractory Wound Secretions.

Chronic refractory wounds were common and the treatments were complicated for burn and plastic surgeons. This study was to investigate the bacterial distribution characteristics and bacterial drug resistance of chronic refractory wound secretions. The authors retrospectively analyzed 425 patients with chronic refractory wound infection. The results of bacterial culture of wound secretions and drug sensitivity test were retrospectively analyzed. Further, the location area of the wound was divided into 4 regions, and the difference of the bacterial culture results between different regions was analyzed. The wound secretions were cultured into 401 bacterial strains, including 206 gram-positive bacteria strains, accounting for 51.4%, with the highest detection rate of Staphylococcus aureus at 26.2% (105/401). There were 195 gram-negative bacteria strains, accounting for 48.6%, with the highest detection rate of Pseudomonas aeruginosa at 14.2% (57/401). There were 6 fungal strains. The proportion of gram-negative bacteria in the III region of the wound zone was significantly greater than that in the other 3 regions. The detection rate of gram-positive bacteria and gram-negative bacteria of chronic refractory wound secretions is not much different. However, in the area close to the perineum (III region), gram-negative bacteria is significantly higher, which has a certain reference value for the use of antibiotics in clinical practice. Level 4.

High-fat meals do not affect thrombin formation and fibrin clot lysis in individuals with obesity during intentional weight loss

Repeated weight loss cycles are associated with increased cardiovascular morbidity. Meal-induced thrombin formation, measured as prothrombin fragment 1+2 (F1+2), is observed in individuals with overweight after weight loss, and postprandial effects can be one of the mechanisms underlying harmful effects during intentional weight loss. We hypothesize that consumption of high-fat meals during intentional weight loss triggers a prothrombotic state by increasing postprandial F1+2 or decreasing fibrin clot lysis in individuals with obesity, and that the response associates with the gut bacteria composition. A cross-over meal study was conducted in patients admitted to bariatric surgery during dietary weight loss (N = 20) and surgical weight loss (N = 16) (weight loss groups). High-fat (67 E%) and low-fat (16 E%) meals were served at 08:15 and 10:00 on 2 study days. Blood samples collected at 08:00 (fasting), 12:00, and 14:00 were analyzed for triglycerides, activated factor VII (FVIIa), F1+2, D-dimer, fibrinogen, tissue factor , and fibrin clot lysis. The proportion of Gram-negative bacteria and bacterial diversity were analyzed in fecal samples obtained less than 24 hours before the meal test. Triglyceride and FVIIa increased after high-fat meals in both weight loss groups, whereas D-dimer (dietary group) and F1+2 decreased and tissue factor and fibrin clot lysis did not change. There was a negative association between the proportion of Gram-negative bacteria and changes in FVIIa in the surgery group. Postprandial FVII activation after high-fat meals is not accompanied by increased F1+2, irrespective of the weight loss intervention, but might be associated with the proportion of Gram-negative gut bacteria.

Endotoxin in Aerosol Particles from Metalworking Fluids Measured with a Sioutas Cascade Impactor.

The aim of this study was to characterize personal occupational exposure to endotoxin in size-separated airborne particles of MWF aerosol, using a Sioutas cascade impactor (SCI). Exposure to inhalable fractions of MWF aerosol and endotoxin was measured by personal sampling of 52 individuals over an 8-h work shift using a PAS-6 sampler in parallel with a SCI (<0.25, 0.25-0.5, 0.5-1.0, 1.0-2.5, and 2.5-10 µm). Aerosol mass concentration was measured for each worker with a real-time instrument (DataRAM) during a full shift. Samples of MWF were collected from the machines and central tanks during the work shift. A total of 117 measurements of inhalable MWF aerosols were made among 52 workers. The geometric mean of inhalable MWF aerosol was 0.16 mg m-3 air. The geometric mean of endotoxin concentration on the inhalable sampler was 0.15 EU m-3. Airborne endotoxin was found on all size fractions from the impactor, with the major part seen in the fraction (2.5-10 µm). There was a correlation between the inhalable fraction of endotoxin measured by the PAS-6 sampler and on the SCI sampler (2.5-10 µm), estimated to be 0.51 for all samples (P < 0.0001). The concentration of endotoxin varied between the MWFs, as did the proportion of Gram-negative bacteria among the culturable bacteria (>80% in one MWF and <1.5% in the other three). The personal exposure to inhalable fractions of endotoxin contained in the MWF aerosol were low, where most of the endotoxin were found in fraction (2.5-10 µm), measured by SCI. There are differences between factories and MWF systems regarding the distribution of endotoxin and so results from one context should not be generalized to other plants and systems. Compressed air was used for less than 10 min shift-1. The mixed-effect model showed that working with open machines and grinding as cutting task were important determinants of exposure to inhalable aerosol. It is important to keep occupational exposure to aerosols low with the help of good ventilation systems, enclosed machines, and organization of work.

Identification of the microbiota in sugar extraction juices by sequencing-based techniques

The importance of microorganisms in the beet sugar industry came up in 1930. Since then, several approaches have been made to describe these bacteria. For this purpose, mainly cultivation-based methods were applied. However, the majority of the microorganisms cannot be cultivated or are in the viable-but-non-culturable state. In addition, these methods are time-consuming and costly. Progress in molecular biology allows a cheaper, faster and more precise identification of the microbiota. This study evaluates the application of an 16S rDNA-based metagenomic sequencing approach based on Illumina MiSeq technology to identify the microbiota in raw juice and juice of mid-tower in a beet sugar production plant and compares the results with those obtained by cultivation-based techniques. All bacteria orders detected with cultivation-based methods could be also found with the applied metagenomic approach. In raw juice, mainly mesophilic bacteria such as Lactobacillus spp. and Leuconostoc spp. species were identified. Additionally, a partly large proportion of gram-negative bacteria belonging to the order Enterobacterales were detected by the metagenomic approach. The diversity in juice of mid-tower was much lower and predominated by mainly thermophilic genera such as Geobacillus, Caldanaerobius and Thermoanaerobacter. The last two mentioned genera belong to the class of Clostridia. Surprisingly, in the juice of mid-tower Lactobacillus species could be verified by cultivation-based methods as well as by the metagenomic approach. As a consequence, it can be presumed that lactobacilli can survive in this very specific environment at 70 °C occurring in the central part of the extraction tower.

Microbial profile, antimicrobial resistance, and molecular characterization of diabetic foot infections in a university hospital.

Diabetic foot infections (DFIs) are among the most severe complications of diabetes. The aim of this study was to determine the etiological pathogens of DFIs in different Wagner's and IDSA/IWGDF grades, and to assess their antimicrobial susceptibility pattern together with molecular characterization of antibiotic resistance genes. A prospective study was conducted on 120 DFI patients at Main Alexandria University Hospital, Egypt. The aerobic and anaerobic etiological pathogens were determined using semi-quantitative culture and PCR respectively. The antimicrobial susceptibility pattern was done according to Clinical Laboratory Standards Institute guidelines. Detection of carbapenemases and class-1 integron genes was carried out by polymerase chain reaction (PCR). A total of 178 (124 aerobic, 54 anaerobic) pathogens were identified from patients with DFI, with an average of 1.82 isolates/subject. Among aerobic pathogens, Gram-negative predominated (98/124; 79%), of which Pseudomonas spp. and Proteus spp. were the most common. MRSA constituted more than 50% of Gram-positive isolates. Polymicrobial infection was found in 42 (42.9%) subjects. The proportion of Gram-negative bacteria and anaerobes increased with increased DFI grades and severity. Multidrug and extensively drug resistant isolates were observed in 86 patients (87.7%). PCR identified carbapenemases genes in 14 (11.7%) and class 1 integron in 28 (23.3%) DFI cases. Vancomycin, teicoplanin, linezolid were the most effective antimicrobial agents against Gram-positive pathogens, while colistin, imipenem, meropenem, and piperacillin-tazobactam were effective against Gram-negative pathogens. Multidrug and extensively drug resistant Gram-negative bacteria were the dominant pathogens among all DFI severity grades. However, the proportion of Gram-positive bacteria decreased with the severity of infection. The clinical role of our relatively high rate of anaerobes should be investigated. The results found in this study could be beneficial for designing future empiric antimicrobial protocols in relation to the severity of DFIs.

Prevalence and Antibiotic Resistance Profile of Cerebrospinal Fluid Pathogens from Neurosurgical Patients from Level 1 Trauma Center in India.

Introduction:The purpose of this study was to investigate the prevalence of Postoperative central nervous system infections (PCNSIs) and antibiotic resistance profiles of causative organisms in trauma patients following neuroinvasive procedures.Materials and Methods:This was a retrospective study conducted over a period of 4 years (2013–2017). All in-patients admitted under a neurotrauma unit meeting the inclusion criteria of PCNSIs were included in the study. Surgical site infections (SSIs) were defined according to the Centers for Disease Control and Prevention 2018 (CDC) criteria. We retrospectively examined the demographic characteristics, type of neurosurgery performed, laboratory data, causative organisms, and antimicrobial susceptibility testing results of patients who had positive cerebrospinal fluid cultures following craniotomy between January 2013 and December 2017.Results:Of total 2500 patients operated during the study, 961 patients were screened for PCNSIs. The estimated prevalence (95% confidence interval) of PCNSIs which is a type of organ/space SSI was 7.2% (6.3–8.3). Males were predominantly affected (85.0%). The mean age (standard deviation) of patients was 31.9 (16.5) years. Of all the cultures sent for microbiological examination, 18.6% were positive. The proportion of Gram-negative bacteria causing PCNSIs was 91.6%. Multidrug-resistant (MDR) Acinetobacter baumannii (41%) was the most common organism isolated. Among Gram-positive bacteria, the most common organism was Staphylococcus aureus (5.5%). All the Gram-positive isolates were susceptible to vancomycin, teicoplanin, and linezolid.Conclusion:There is a high burden of PCNSI caused by MDR Acinetobacter baumannii can pose a major clinical challenge with only few antimicrobials left in the pipeline.

Bacterial Profile and Antibiotic Resistance in Patients with Diabetic Foot Ulcer in Guangzhou, Southern China: Focus on the Differences among Different Wagner's Grades, IDSA/IWGDF Grades, and Ulcer Types.

Objective To understand the bacterial profile and antibiotic resistance patterns in diabetic foot infection (DFI) in different Wagner's grades, IDSA/IWGDF grades, and different ulcer types in Guangzhou, in order to provide more detailed suggestion to the clinician about the empirical antibiotic choice. Methods 207 bacteria were collected from 117 DFIs in Sun Yat-sen Memorial Hospital from Jan.1, 2010, to Dec.31, 2015. The clinical data and microbial information were analyzed. Results The proportion of Gram-negative bacteria (GNB) was higher than Gram-positive bacteria (GPB) (54.1% versus 45.9%), in which Enterobacteriaceae (73.2%) and Staphylococcus (65.2%) were predominant, respectively. With an increasing of Wagner's grades and IDSA/IWGDF grades, the proportion of GNB bacterial infection, especially Pseudomonas, was increased. Neuro-ischemic ulcer (N-IFU) was more susceptible to GNB infection. Furthermore, with the aggravation of the wound and infection, the antibiotic resistance rates were obviously increased. GPB isolated in ischemic foot ulcer (IFU) showed more resistance than the N-IFU, while GNB isolates were on the opposite. Conclusions Different bacterial profiles and antibiotic sensitivity were found in different DFU grades and types. Clinician should try to stay updated in antibiotic resistance pattern of common pathogens in their area. This paper provided them the detailed information in this region.