Comparison of bacterial species and clinical outcomes in patients with diabetic hand infection in tropical and nontropical regions.

Hand infection is a rare complication in patients with diabetes. Its clinical outcomes depend on the severity of hand infection caused by bacteria, but the difference in bacterial species in the regional disparity is unknown. The purpose of this study was to explore the influence of tropical and nontropical regions on bacterial species and clinical outcomes for diabetic hand. A systematic literature review was conducted using PubMed, EMBASE, Web of Science, and Google Scholar. Moreover, the bacterial species and clinical outcomes were analyzed with respect to multicenter wound care in China (nontropical regions). Both mixed bacteria (31.2% vs. 16.6%, p = 0.014) and fungi (7.5% vs. 0.8%, p = 0.017) in the nontropical region were significantly more prevalent than those in the tropical region. Staphylococcus and Streptococcus spp. were dominant in gram-positive bacteria, and Klebsiella, Escherichia coli, Proteus and Pseudomonas in gram-negative bacteria occupied the next majority in the two regions. The rate of surgical treatment in the patients was 31.2% in the nontropical region, which was significantly higher than the 11.4% in the tropical region (p = 0.001). Although the overall mortality was not significantly different, there was a tendency to be increased in tropical regions (6.3%) compared with nontropical regions (0.9%). However, amputation (32.9% vs. 31.3%, p = 0.762) and disability (6.3% vs. 12.2%, p = 0.138) were not significantly different between the two regions. Similar numbers of cases were reported, and the most common bacteria were similar in tropical and nontropical regions in patients with diabetic hand. There were more species of bacteria in the nontropical region, and their distribution was basically similar, except for fungi, which had differences between the two regions. The present study also showed that surgical treatment and mortality were inversely correlated because delays in debridement and surgery can deteriorate deep infections, eventually leading to amputation and even death.

Comparison of bacterial species and clinical outcomes in patients with diabetic hand infection in tropical and nontropical regions.

Purpose: Hand infection is a rare complication in patients with diabetes. Its clinical outcomes depend on the severity of hand infection caused by bacteria, but the difference in bacterial species in the regional disparity is unknown. The purpose of this study was to explore the influence of tropical and nontropical regions on bacterial species and clinical outcomes for diabetic hand. Patients and Methods: A systematic literature review was conducted using PubMed, EMBASE, Web of Science, and Google Scholar. Moreover, the bacterial species and clinical outcomes were analyzed with respect to multicenter wound care in China (nontropical regions). Results: Both mixed bacteria (31.2% vs. 16.6%, p=0.014) and fungi (7.5% vs. 0.8%, p=0.017) in the nontropical region were significantly more prevalent than those in the tropical region. Staphylococcus and Streptococcus spp. were dominant in gram-positive bacteria, and Klebsiella, Escherichia coli, Proteus and Pseudomonas in gram-negative bacteria occupied the next majority in the two regions. The rate of surgical treatment in the patients was 31.2% in the nontropical region, which was significantly higher than the 11.4% in the tropical region (p=0.001). Although the overall mortality was not significantly different, there was a tendency to be increased in tropical regions (6.3%) compared with nontropical regions (0.9%). However, amputation (32.9% vs. 31.3%, p=0.762) and disability (6.3% vs. 12.2%, p=0.138) were not significantly differentbetween the two regions. Conclusion: Similar numbers of cases were reported, and the most common bacteria were similar in tropical and nontropical regions in patients with diabetic hand. There were more species of bacteria in the nontropical region, and their distribution was basically similar, except for fungi, which had differences between the two regions. The present study also showed that surgical treatment and mortality were inversely correlated because delays in debridement and surgery can deteriorate deep infections, eventually leading to amputation and even death.

Bacterial distinctions in practical rural sewage collection systems caused by the location, season, and system type.

Bacteria in rural sewage collection systems have the important influences on operation and maintenance risks, such as sedimentation blockage and harmful gas accumulation, and pollutant pre-treatment ability. It is necessary to analyze and interpret the influence on bacterial communities caused by the location (sewage, biofilms, and deposits), season (winter and spring, summer and autumn), and system type (sewers and ditches) to better understand the bacterial characteristics in rural sewage collection systems. To achieve the above purpose, 96 samples obtained from practical rural sewage collection systems in eight villages were analyzed by 16S rRNA whole region sequencing methods. The results indicate that locations and seasons caused significant influences on the overall bacterial communities, which were mainly affected by temperature, sewage quality and bacterial survival preference, and 13 genera of sulfate-reducing bacteria (SRB), 2 genera of ammonia-oxidizing bacteria (AOB), 2 genera of nitrite-oxidizing bacteria (NOB), and 9 genera of water-related pathogenic bacteria (WPB) were detected in rural sewage collection systems. SRB, AOB, NOB, and WPB tended to inhabit in biofilms or deposits rather than in sewage. The total relative abundance of SRB in summer and autumn (∼2.19%) was higher than in winter and spring (∼0.41%), and the WPB distribution in different seasons showed significant distinction. Additionally, some of SRB, AOB, NOB, and WPB also showed significant differences in sewers and ditches. Overall, this study provided a deeper understanding of bacteria in rural sewage collection systems and could further provide the basic parameter for the operation and maintenance risk control.

Microbial distributions in the conjunctiva and lacrimal sacs of patients with chronic dacryocystitis in a tertiary hospital.

BACKGROUND: The aim was to clarify the distributions of bacteria in the conjunctival sac and lacrimal sac in patients with chronic dacryocystitis. METHODS: In total, 297 (322 eyes) chronic dacryocystitis patients who underwent nasal endoscopic dacryocystorhinostomy (EN-DCR) were included. Conjunctival sac secretions from the affected eye were collected preoperatively, and lacrimal sac retention fluid from the affected side in the same patient was collected intraoperatively. Bacterial culture and drug sensitivity testing were performed to determine bacterial distributions. RESULTS: In total, 127 bacterial isolates (49 species) were detected in 123 eyes in the conjunctival group, with a positivity rate of 38.2% (123/322); 85 bacterial isolates (30 species) were detected in 85 eyes in the lacrimal sac group, with a positivity rate of 26.4% (85/322). The positivity rates were significantly different (P = 0.001) between two groups. The gram-negative bacilli proportion in the lacrimal sac group (36/85, 42.4%) was significantly higher than that in the conjunctival sac group (37/127, 29.2%) ( P = 0.047). Positive conjunctival sac secretion culture (123/322) was significantly associated with increased ocular secretion (281/322, 87.3%) (P = 0.002). Among the culture-positive bacteria in the conjunctival sac group and the lacrimal sac group, 30/127, 23.6% and 43/127, 26.7% and 21/85, 24.7% and 20/85, 23.5% were resistant to levofloxacin and tobramycin, respectively. CONCLUSIONS: This study illustrated differences in bacterial distributions between conjunctival sac secretions and retained lacrimal sac fluid in chronic dacryocystitis patients, with a higher proportion of gram-negative bacilli in lacrimal sac secretions. The ocular surface flora in chronic dacryocystitis patients is partially resistant to levofloxacin and tobramycin, which need to be considered by ophthalmologists.

Spatial and Seasonal Patterns of Sediment Bacterial Communities in Large River Cascade Reservoirs: Drivers, Assembly Processes, and Co-occurrence Relationship.

Sediment bacteria play an irreplaceable role in promoting the function and biogeochemical cycle of the freshwater ecosystem; however, little is known about their biogeographical patterns and community assembly mechanisms in large river suffering from cascade development. Here, we investigated the spatiotemporal distribution patterns of bacterial communities employing next-generation sequencing analysis and multivariate statistical analyses from the Lancang River cascade reservoirs during summer and winter. We found that sediment bacterial composition has a significant seasonal turnover due to the modification of cascade reservoirs operation mode, and the spatial consistency of biogeographical models (including distance-decay relationship and covariation of community composition with geographical distance) also has subtle changes. The linear regression between the dissimilarity of bacterial communities in sediments, geographical and environmental distance showed that the synergistic effects of geographical and environmental factors explained the influence on bacterial communities. Furthermore, the environmental difference explained little variations (19.40%) in community structure, implying the homogeneity of environmental conditions across the cascade reservoirs of Lancang River. From the quantification of the ecological process, the homogeneous selection was recognized as the dominating factor of bacterial community assembly. The co-occurrence topological network analyses showed that the key genera were more important than the most connected genera. In general, the assembly of bacterial communities in sediment of cascade reservoirs was mediated by both deterministic and stochastic processes and is always dominated by homogeneous selection with the seasonal switching, but the effects of dispersal limitation and ecological drift cannot be ignored.

Epidemiology and antibiotic resistance of prosthetic joint infections according to time of occurrence, a 10-year study.

OBJECTIVES: To describe the microorganisms responsible for prosthetic joint infections (PJIs) and their antimicrobial susceptibilities, and to propose appropriate empirical antimicrobial treatments (EATs) according to time of occurrence METHODS: This 10-year retrospective study presents the bacterial etiology of 282 consecutive PJIs in a French hospital according to time of occurrence (adapted from Zimmerli's classification: early, <3 months; delayed, 3-12 months; late acute, >12 months with hematogenous seeding or contiguous spread; late chronic, >12 months without hematogenous seeding). The expected efficacy of various EATs was analyzed for each PJI. RESULTS: Staphylococci were the most commonly found bacteria (S. aureus (44.3%), coagulase-negative staphylococci (25.2%) with 15.2% and 49.3% methicillin resistance, respectively), followed by Gram-negative bacilli (GNB) (17.7%) and streptococci (14.9%). The distribution of species varied between categories, but antibiotics targeting GNBs were required in all categories. Imipenem-vancomycin was the most effective combination (99.3%) but should be reserved for patients with suspected resistant GNB. Cefotaxime-vancomycin was less effective in early/delayed and late PJIs (91.1% and 86.1%, respectively), due to resistant GNB and polymicrobial infections. Piperacillin/tazobactam-vancomycin appeared to be appropriate in all situations (>96% efficacy). CONCLUSION: Proposing universal recommendations remains challenging, but a good understanding of the local epidemiology is important for optimizing EATs.

Bacterial Distribution and Community Structure in Beef Cattle Liver and Bile at Slaughter.

ABSTRACT: In this study, the distribution of hygienic indicator bacteria in cattle livers and bile was examined at slaughterhouses. One hundred twenty-seven cattle livers with gallbladders were carefully eviscerated from carcasses at 10 slaughterhouses. Microbiological examination revealed that nine bile samples (7.1% prevalence) and 19 liver parenchyma samples (15.0% prevalence) were positive for Enterobacteriaceae (EB) with means ± standard deviations of 3.68 ± 4.63 log CFU/mL and 1.59 ± 2.47 log CFU/g, respectively; thus, bacterial contamination was apparent even at the postevisceration stage. Subsequently, 70 cattle livers were obtained at the postprocessing and storage stage from 7 of the 10 slaughterhouses. Microbiological analysis revealed significantly higher levels of EB in the liver parenchyma (3.00 ± 3.89 log CFU/g, P = 0.011) than those at the postevisceration stage, suggesting that bacterial dissemination and/or replication occurred in the liver parenchyma during processing and storage. According to 16S rRNA ion semiconductor sequencing analysis of representative samples from 12 cattle, Proteobacteria, Firmicutes, and Actinobacteria were dominant in both the parenchyma and bile in which EB and Escherichia coli were predominant among livers with higher EB levels. These results suggest that bile plays a role as a vehicle for bacterial transmission to the liver parenchyma. This study is the first to evaluate bacterial distribution and community structure in the liver and biliary microecosystem of cattle at slaughter. Our data support the use of EB testing of bile to screen cattle livers contaminated with high levels of fecal indicator bacteria.

Distribution and antimicrobial resistance profile of bacteria recovered from sewage system of health institutions found in Hawassa, Sidama Regional State, Ethiopia: A descriptive study.

OBJECTIVES: The aim of the study was to determine the distribution and antimicrobial susceptibility profile of bacteria recovered from the sewage systems of health institutions found in Hawassa, Sidama Regional State, Ethiopia. METHODS: A cross-sectional study was conducted from 20 October 2020 to 1 December 2020. A total of 27 sewage samples were collected at two points, namely, before entering the septic tank and from the septic tank of seven health institutions. Samples were inoculated onto Mannitol salt agar, Blood agar, and MacConkey agar, and incubated for 24 h at 37°C. Bacteria were identified using colony morphology, Gram staining, and biochemical tests. An antimicrobial susceptibility test was performed using the Kirby-Bauer disk diffusion method. Data were analyzed by SPSS, version 25, and results were presented in text and tables. RESULTS: All sewage samples (n = 27) examined in the current study contained potential pathogenic bacteria. Overall, 129 different types of bacteria were identified. Of isolated bacteria, 14 (10.8%) were Gram positive, while 115 (89.2%) were Gram negative. The most prevalent bacteria were Escherichia coli (n = 27, 20.9%) followed by Shigella species (n = 26, 20.2%), Pseudomonas species (n = 25, 19.4%), Salmonella species (n = 25, 19.4%), Staphylococcus aureus (n = 14, 10.9%), and Klebsiella species (n = 12, 9.3%). All bacteria were susceptible to azithromycin. About 80% of bacteria were resistant to ampicillin, whereas greater than 80% of bacteria were susceptible to norfloxacin, ciprofloxacin, and gentamicin. CONCLUSION: All sewage systems of health institutions included in the current study contained different types of pathogenic bacteria, which are resistant to commonly prescribed antibiotics.

Microbial fuel cell-upflow biofilter coupling system for deep denitrification and power recovery: Efficiencies, bacterial succession and interactions.

The excess organic carbon is often added to meet denitrification requirements during municipal wastewater treatment, resulting in the carbon waste and increased risk of secondary pollution. In this study, microbial fuel cell (MFC) was coupled with an up-flow denitrification biofilter (BF), and the long-term performances of denitrification and power output were investigated under the different carbon source concentration. With sodium acetate (NaAc) of 600 mg/L and 300 mg/L, the favorable denitrification efficiencies were obtained (98.60%) and the stable current output was maintained (0.44 mÃ0.48 mA). By supplying NaAc of 150 mg/L, the high denitrification efficiency remained in a high range (89.31%) and the current output maintained at 0.12 mA, while, the denitrification efficiency dropped to 71.34% without coupling MFC. Electron balance analysis indicated that both nitrate removal and electron recovery efficiencies were higher in MFC-BF than that in BF, verifying the improved denitrification and carbon utilization performance. Coupling MFC significantly altered the bacterial community structure and composition, and while, the diversified abundance and distribution of bacterial genera were observed at the different locations. Compared with BF, the more exoelectrogenic genera (Desulfobacterium, Trichococcus) and genera holding both denitrifying and electrogenic functions (Dechloromonas, Geobacter) were found dominated in MFC-BF. Instead, the dominating genera in BF were Dechloromonas, Desulfomicrobium, Acidovorax and etc. By coupling MFC, the more complex and diversified network and the closer interaction relationships between the dominant potential functional genera were found. The study provides a feasible approach to effectively improve the denitrification efficiency and organic carbon recovery for deep denitrification process.

Influence of microbial spatial distribution and activity in an EGSB reactor under high- and low-loading denitrification desulfurization.

To characterize the impact of reactor configuration and influent loading on elemental sulphur (S0) recovery during denitrification desulfurization, a laboratory-scale expanded granular sludge bed (EGSB) reactor was established under two influent acetate/nitrate/sulphide loadings; the water flow velocity, microbial community, and functional genes at different heights were investigated. There was no S0 generated when acetate/nitrate/sulphide loadings were set to 0.95/0.60/1.05 kg/m3.d (low-loading). Furthermore, there were no typical denitrifying sulphide oxidizing bacteria under this condition, and Syntrophobacter, Anaerolineaceae genera were predominant in the reactor. As the influent loading was doubled (high-loading), S0 recovery increased to 87%; the bacterial distribution was relatively homogeneous with sulphide oxidation genera (Thauera) being predominant. Neither nirK nor sqr genes were detected in the low-loading sample at a height of 50 cm. The sqr/sox ratios of low-loading stage were 2.50 (10 cm), 0.94 (30 cm), and 0 (50 cm), and the ratios of the high-loading stage were 1.38 (10 cm), 1.33 (30 cm), and 1.08 (50 cm). A hydrodynamics analysis indicated that the water flow velocity was homogenous throughout the reactor. Appropriate reactor configuration and operation parameters play an important role in the efficient regulation of S0 recovery during denitrification desulfurization.

Analysis of the distribution and drug resistance of common bacteria in hospital infections in a Grade III class A hospital in 2015-2019 / 公共卫生与预防医学

Objective To determine the distribution of common bacteria in hospital infections and to provide a basis for the prevention and control of bacterial infection and for rational use of antibiotics in clinical departments. Methods A retrospective analysis was conducted on common bacterial strains isolated from inpatients of a Grade III class A hospital from 2015 to 2019, including sample source and drug sensitivity changes. Results A total of 4,924 strains of Escherichia coli, 2 762 strains of Klebsiella pneumoniae, 1 297 strains of Staphylococcus aureus, 967 strains of Pseudomonas aeruginosa, and 1 585 strains of Acinetobacter baumannii were detected during the past 5 years. The bacteria were detected mainly from sputum. The resistance rate of Escherichia coli to ampicillin was as high as 88%, and the resistance rate to ceftriaxone was 58.22%. The resistance rate of Klebsiella pneumoniae to ampicillin was higher than 97%. The resistance rate of Staphylococcus aureus to penicillin G reached 93%, and the resistance rates to erythromycin and clindamycin were 60% and 70%, respectively. Pseudomonas aeruginosa had a high resistance rate to ampicillin, but a low resistance rate to other types of antibiotics. Acinetobacter baumannii had a high resistance to common antibacterial drugs. Conclusion Escherichia coli and Klebsiella pneumoniae had a high incidence of nosocomial infections. Pseudomonas aeruginosa and Acinetobacter baumannii both showed serious multi-drug resistance. Clinical departments should strengthen the monitoring of drug sensitivity changes of pathogenic bacteria, and manage and use antibiotics purposefully.

Distribution characteristics and drug resistance changes of bacteria detected in the pediatric intensive care unit / 中华实用儿科临床杂志

Objective:To investigate the tendency of bacterial distribution and drug resistance of clinically isolated pathogens in the pediatric intensive care unit (PICU), which provided references for the reasonable application of antibiotics.Methods:The distribution characteristics of all clinical isolates from PICU of Children′s Hospital of Shanghai Jiaotong University from January 2010 to December 2018 and their trend of drug resistance were retrospectively analyzed.Results:A total of 2 749 strains of bacteria were isolated, including 1 912 strains (69.6%) Gram-negative bacteria and 837 strains (30.4%) Gram-positive bacteria.The top 6 detected bacteria were Acinetobacter baumannii (749 stains, 27.2%), Klebsiella pneumoniae (289 stains, 10.5%), Staphylococcus aureus (214 stains, 7.8%), Stenotrophomonas maltophilia (207 stains, 7.5%), Escherichia coli (204 stains, 7.4%) and Pseudomonas aeruginosa (189 stains, 6.9%). Among them, the detective rate of Maltophilia Stenotrophomonasannually increased from 6 strains (2.8%) in 2010 to 39 strains (9.5%) in 2018.The resistance rates of Acinetobacter baumannii and Klebsiella pneumoniae to carbapenems increased year by year, which was up to 96.0% and 71.4% to Meropenem by 2018.Their resistance rates to the third-generation cephalosporins, aminoglycosides and sulfonamides were higher than 70.0%.The sensitivity rate to Tigecycline and Polymyxin was 100.0%.The detection rate of Methicillin-resistant Staphylococcus aureus (MRSA) significantly increased from 18.2% in 2010 to 50.0% in 2018 ( χ2=19.38, P=0.013). No Vancomycin-resistant strains were found. Conclusions:Gram-negative bacteria are the main clinical isolates of PICU.Acinetobacter baumannii, Klebsiella pneumoniae, and especially Pseudomonas maltophilus, have a significant growth trend in the detection rate. Acinetobacter baumannii and Klebsiella pneumoniae are highly resistant to carbapenems.MRSA annually grows, but it still maintains a high degree of sensitivity to Vancomycin.

Analyses of the Bacterial Contamination on Belgian Broiler Carcasses at Retail Level.

Broilers are not equally exposed to bacterial contamination during rearing and processing, resulting in areas with different bacterial communities on carcasses at retail. The determination of these communities is also affected by the examination methods applied. The present study aimed to assess the bacterial communities on neck, breast, and back skin on broiler carcasses at retail through classical International Organization of Standardization based isolation methods combined with identification by matrix-assisted laser desorption ionization time-of-flight mass spectrum (MALDI-TOF MS) and 16S amplicon sequencing. Twelve commercially and eight organically reared broilers slaughtered in four slaughterhouses were examined. Significantly higher anaerobic bacterial counts were observed on the neck skin than on the breast and back skin. By the combination of cultivation and amplicon sequencing, remarkable shifts in bacterial communities were determined on the breast and back skin, but not on the neck skin. Although the aerobic bacteria contamination levels were not different between the areas, different bacterial communities were observed. The impact of the slaughterhouse to the overall microbial composition was rather small. Organically reared broilers had unique bacterial communities. In conclusion, compared to the breast skin, the neck, and back skin had a larger potential for bacterial spoilage, in particular when anaerobic storage conditions are applied. The distribution of bacteria on the different areas could be related to the contamination during slaughter as well as the bird-rearing methods.

The prevalence and bacterial distribution of peritonitis amongst adults undergoing continuous ambulatory peritoneal dialysis at Universitas hospital.

BACKGROUND: Peritonitis is the leading cause of morbidity and technique failure in peritoneal dialysis (PD) patients. The International Society for Peritoneal Dialysis (ISPD) recommends each centre to monitor the peritonitis rates and the causative organisms in order to guide local empiric antibiotic protocols. The aim of this study was to report on the peritonitis rates and describe the causative microorganisms and the antibiotic susceptibility in continuous ambulatory peritoneal dialysis (CAPD) adult patients at the Universitas Academic Hospital. METHODS: A single-centre, retrospective descriptive survey was conducted to determine the peritonitis rates in PD patients (January-December 2016). All CAPD patients aged ≥18 years, who presented with clinical features of PD-associated peritonitis, were included. The peritonitis episodes were studied per patient, and the causative microorganisms and the antibiotic susceptibility of the organisms were described. RESULTS: One hundred and twenty-eight patients underwent CAPD. The peritonitis rate was 1.45 episodes per year at risk. The prevalence of CAPD patients affected by at least one episode of CAPD-associated peritonitis during 2016 was 56.3%. The majority of episodes (76.7%) (n = 122) were mono-microbial. Gram-positive organisms accounted for 73.0% (n = 116) of the peritonitis episodes, coagulase-negative Staphylococcus being the most common. Gram-negative organisms accounted for 15.7% (n = 25) of the peritonitis episodes, and the common pathogens was Enterobacteriaceae. CONCLUSION: The peritonitis rate was alarmingly high, with 1.45 episodes per year at risk; this is three times more than the recommended 0.5 episodes per year according to the ISPD guidelines. The culture-negative rate of 8.8% is within ISPD-acceptable limits. There is a need to strengthen preventive measures with regard to peritonitis.

Oral Administration of Microencapsulated B. Longum BAA-999 and Lycopene Modulates IGF-1/IGF-1R/IGFBP3 Protein Expressions in a Colorectal Murine Model.

The Insulin-like growth factor-I/Insulin-like growth factor-I receptor (IGF-1/IGF-1R) system is a major determinant in colorectal cancer (CRC) pathogenesis. Probiotics (Bifidobacterium longum, BF) and lycopene (LYC) have been individually researched for their beneficial effects in the prevention of CRC. However, the effect of a combined treatment of microencapsulated BF and LYC on IGF-1/IGF-1R/IGFBPs (Insulin-like growth factor-binding proteins) expression in an azoxymethane (AOM)-dextran sulfate sodium (DSS)-induced CRC model have not been demonstrated. BF was microencapsulated by the spray drying technique, with high viability, and daily gavaged with LYC for 16 weeks to CD-1 mice in an AOM-DSS model. The results indicated that BF- and BF + LYC-treated groups had significantly lower inflammation grade, tumor incidence (13-38%) and adenocarcinoma (13-14%) incidence compared to the AOM + DSS group (80%), whereas LYC treatment only protected against inflammation grade and incidence. Caecal, colonic and fecal pH and ß-glucuronidase (ß-GA) values were significantly normalized by BF and LYC. Similarly, BF and BF + LYC treatments significantly reduced both the positive rate and expression grade of IGF-1 and IGF-1R proteins and normalized Insulin-like growth factor-binding protein-3 (IGFBP3) expression. Based on intestinal parameters related to the specific colon carcinogenesis in an AOM-DSS-induced model, LYC and microencapsulated BF supplementation resulted in a significant chemopreventive potential through the modulation of IGF-1/IGF-1R system.

Adhesive Interactions Between Lactic Acid Bacteria and ß-Lactoglobulin: Specificity and Impact on Bacterial Location in Whey Protein Isolate.

In the last decade, there has been an increasing interest in the potential health effects associated with the consumption of lactic acid bacteria (LAB) in foods. Some of these bacteria such as Lactobacillus rhamnosus GG (LGG) are known to adhere to milk components, which may impact their distribution and protection within dairy matrices and therefore is likely to modulate the efficiency of their delivery. However, the adhesive behavior of most LAB, as well as its effect on food structuration and on the final bacterial distribution within the food matrix remain very poorly studied. Using a recently developed high-throughput approach, we have screened a collection of 73 LAB strains for their adhesive behavior toward the major whey protein ß-lactoglobulin. Adhesion was then studied by genomics in relation to common bacterial surface characteristics such as pili and adhesion-related domain containing proteins. Representative adhesive and non-adhesive strains have been studied in further depth through biophysical measurement using atomic force microscopy (AFM) and a relation with bacterial distribution in whey protein isolate (WPI) solution has been established. AFM measurements have revealed that bacterial adhesion to ß-lactoglobulin is highly specific and cannot be predicted accurately using only genomic information. Non-adhesive strains were found to remain homogeneously distributed in solution whereas adhesive strains gathered in flocs. These findings show that several LAB strains are able to adhere to ß-lactoglobulin, whereas this had only been previously observed on LGG. We also show that these adhesive interactions present similar characteristics and are likely to impact bacterial location and distribution in dairy matrices containing ß-lactoglobulin. This may help with designing more efficient dairy food matrices for optimized LAB delivery.

Enhanced microbial metabolism in one stage partial nitritation-anammox system treating low strength wastewater by novel composite carrier.

One stage partial nitritation-anammox (PN-A) process has attracted more and more attention due to the low investment cost but the instability in treating low strength wastewater. In this study, for producing a novel composite carrier that could provide high ammonia microenvironment in low strength wastewater, the zeolites and floating materials were combined in the spherical shell and distributed evenly by the spherical polyhedron. And a moving bed biofilm reactor (MBBR) with the composite carriers and ordinary carriers without zeolites as control group was operated for nearly 120 days. The PN-A process were realized in 53 days, and the total nitrogen removal efficiency reached around 85% at influent ammonium concentration of 50 mg/L finally. Analysis of 16S rRNA gene sequencing revealed that the composite carriers showed significant promotion on the proliferation of ammonium oxidizing bacteria (AOB) and enrichment of anaerobic ammonium oxidizing bacteria (AnAOB), accounting for 19.14% and 41.65% on the surface, respectively. Moreover, the existence of relative higher abundance of ammonia on the composite carrier surface was validated by the metabolite biomarker of glutamate and especially spermidine. The metabolomics analysis and 16S rRNA function prediction showed that the protein synthesis pathway was obviously upregulated on the composite carriers surface compared with that on the ordinary carriers surface. The higher abundance of glutamate and putrescine indicated that the composite carrier could stimulate the metabolism and growth of bacteria. The present study provided a functional carrier to realize the transformation of activated sludge system into PN-A system treating low strength wastewater, which is significant to the application of the process in mainstream.

Distribution of comammox and canonical ammonia-oxidizing bacteria in tidal flat sediments of the Yangtze River estuary at different depths over four seasons.

AIMS: To investigate the distribution of complete ammonia oxidizers (comammox) and canonical ammonia-oxidizing bacteria (AOB) in tidal flat sediments of the Yangtze River estuary at different depths over four seasons. METHODS AND RESULTS: A two-step PCR with highly degenerate primers (THDP-PCR), coupled with Illumina Miseq-based sequencing, was used to analyse the distribution of comammox and AOB in tidal flat sediments. The proportion of comammox compared with that of AOB was relatively high in spring. The intermediate sediments (1-5 cm) had higher proportions of comammox than those on the surface (0-1 cm) and lower sediments (5-10 cm). Diversity indices confirmed a higher diversity of comammox in the lower sediments (5-10 cm). The proportion of comammox clade A.1 was much higher than that of comammox clade A.2 in all seasons. Redundancy analysis demonstrated that comammox clade A.1 was negatively correlated with total carbon and ammonium concentrations, whereas the opposite was observed in AOB. CONCLUSIONS: Results revealed the specific distribution of comammox and AOB in tidal flat sediments of the Yangtze River estuary. SIGNIFICANCE AND IMPACT OF THE STUDY: This study will contribute to the understanding of nitrification by comammox and AOB in tidal flat sediments.

Effects of Salmonella enterica serovar Enteritidis infection on egg production and the immune response of the laying duck Anas platyrhynchos.

Persistent colonization of the avian reproductive tract by Salmonella enterica serovar Enteritidis (SE) negatively affects egg production and contaminates the egg. The immune function of the ovary and oviduct is essential for protection from infection and for the production of wholesome eggs. However, the immune response of laying ducks during SE infection is not well-understood. In this study, ducks (Anas platyrhynchos) were infected with SE and were systematically monitored for fecal shedding during a 13-week period. We also assessed bacterial distribution in the reproductive tract and classified infected ducks as resistant or susceptible based on the presence of tissue lesions and on SE isolation from fecal samples. We found that infected animals had persistent, but intermittent, bacterial shedding that resulted in the induction of carrier ducks. Laying rate and egg quality were also decreased after SE infection (P < 0.05). SE readily colonized the stroma, small follicle, isthmus, and vagina in the reproductive tracts of susceptible ducks. Immunoglobulin (IgA, IgG, IgM) levels were higher in susceptible ducks compared with resistant birds (P < 0.05); T-lymphocyte subpopulations (CD3+, CD4+, CD8+) displayed the opposite trend. qRT-PCR analysis was used to examine expression profiles of immune response genes in the reproductive tract of infected ducks. The analysis revealed that immune genes, including toll-like receptors (TLR2, TLR4-5, TLR15, TLR21), NOD-like receptors (NOD1, NLRX1, NLRP12), avian ß-defensins (AvßD4-5, AvßD7, AvßD12), cytokines (IL-6, IL-1ß, IFN-γ), and MyD88 were markedly upregulated in the reproductive tracts of SE-infected ducks (all P < 0.05); TLR3, TLR7, NLRC3, NLRC5, and TNF-α were significantly downregulated. These results revealed that SE infection promoted lower egg production and quality, and altered the expression of TLRs, NLRs, AvßDs, and cytokine family genes. These findings provide a basis for further investigation of the physiological and immune mechanisms of SE infection in laying ducks.

Bacterial flora distribution and antimicrobial resistance of pyogenic liver abscess: a multicenter retrospective study (A report of 897 cases) / 中华消化外科杂志

Objective@#To investigate the bacterial flora distribution and antimicrobial resistance of patients with pyogenic liver abscess (PLA) in multi-centers of China.@*Methods@#The retrospective and descriptive study was conducted. The clinical data of 897 patients with PLA at 3 medical centers in China from October 2007 to April 2018 were collected, including 656 cases in the First Hospital of Harbin Medical University, 109 cases in Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology and 132 cases in the Eastern Hepatobiliary Surgery Hospital of Naval Military Medical University. There were 582 males and 315 females, aged (59±11)years, with a range of 6-86 years. Observation indicators: (1) bacterial flora distribution; (2) bacterial resistance. Measurement data with normal distribution were represented as Mean±SD and measurement data with skewed distribution were represented as M (range). Count data were described as absolute numbers or percentages.@*Results@#(1) Bacterial flora distribution: among 897 patients, 733 cases of Klebsiella pneumoniae, 75 cases of Escherichia coli, 11 cases of Staphylococcus aureus, 10 cases of Streptococcus viridians, 9 cases of Klebsiella pneumoniae subsp. pneumoniae, 7 cases of β-emolytic streptococcus, 6 cases of Acinetobacter baumannii, 5 cases of Streptococcus intermadius, 5 cases of Enterococcus faecium, 3 cases of Alcaligenes xylosoxidans subsp. xylosoxidans, 2 cases of Proteus mirabilis, 2 cases of Streptococcus isthmus, 2 cases of Enterobacter cloacae subsp. cloacae, 1 case of Citrobacter koseri, 1 case of Proteus vulgaris, 1 case of Pasteurella pneumotropica, 1 case of Curobacter freudii, 1 case of Enterobacter amnigenus, 1 case of Stenotrophomonas maltophilia, 1 case of Acinetobacter lwoffii, 1 case of Streptococcus salivarius, 1 case of Streptococcus bacterium, 1 case of Enterococcus avium, 1 case of Enterococcus faecalis, 1 case of Klebsiella oxytoca, and 1 case of Staphylococcus epidermidis were cultured in the pus respectively. There were 12 cases of double bacterial infection, and 2 cases of multiple bacterial infections. (2) Bacterial resistance. ① Resistance of Klebsiella pneumoniae and Escherichia coli: the drug resistance rates of Klebsiella pneumoniae to ampicillin, piperacillin, cefazolin, cefuroxime, cefotaxime, ceftriaxone, ceftazidime, cefotetan, cefepime, cefoxitin, amoxicillin/carat Retinoic acid, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, aztreonam, imipenem, meropenem, ertapenem, gentamicin, tobramycin, amikacin, tigaricycline, ciprofloxacin, levofloxacin, and trimethoprim sulfamethoxazole were 99.79%(474/475), 4.09%(7/171), 12.18%(82/673), 7.34%(49/668), 2.34%(4/171), 1.96%(11/562), 5.85%%(10/171), 0(0/562), 0.55%(4/733), 1.42%(9/635), 0(0/733), 2.46%(18/733), 0.55%(4/733), 0.27%(2/733), 1.36%(10/733), 0.14%(1/733), 0(0/733), 0.36%(2/562), 0.95%(7/733), 0.41%(3/733), 0(0/733), 0(0/562), 1.64%(12/733), 0.95%(7/733), and 4.50%(33/733), respectively. The drug resistance rates of Escherichia coli to above antibiotics were 78.67%(59/75), 40.91%(18/44), 65.33%(49/75), 56.00%(42/75), 38.64%(17/44), 41.94%(13/31), 20.00%(15/75), 3.23%(1/31), 25.33%(19/75), 5.77%(3/52), 18.67%(14/75), 32.00%(24/75), 8.00%(6/75), 16.00%(12/75), 37.33%(28/75), 1.33%(1/75), 0(0/75), 0(0/31), 40.00%(30/75), 14.67%(11/75), 1.33%(1/75), 0(0/31), 54.67%(41/75), 37.33%(28/75), and 52.00%(39/75), respectively. ② Drug resistance of other Gram-negative bacteria: the drug resistance rates of Klebsiella pneumoniae subsp. pneumoniae to ampicillin, cefazolin, cefuroxime, ceftriaxone, ceftazidime, cefotetan, cefepime, amoxicillin/carat Retinoic acid, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, aztreonam, imipenem, meropenem, ertapenem, gentamicin, tobramycin, amikacin, ciprofloxacin, levofloxacin, and trimethoprim sulfamethoxazole were 8/8, 0/5, 0/5, 0/1, 0/9, 0/2, 0/9, 0/8, 0/9, 0/9, 0/6, 0/9, 0/9, 0/7, 0/1, 0/9, 0/8, 0/9, 0/9, 0/9, and 0/9. The drug resistance rates of Acinetobacter baumannii to ceftriaxone, ceftazidime, cefepime, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, aztreonam, imipenem, meropenem, gentamicin, tobramycin, amikacin, tigaricycline, ciprofloxacin, levofloxacin, and trimethoprim sulfamethoxazole were 2/6, 4/6, 3/6, 0/6, 4/6, 1/6, 2/6, 4/6, 2/6, 4/6, 4/6, 3/6, 0/6, 4/6, 2/6, and 3/6, respectively. The drug resistance rates of Alcaligenes xylosoxidans subsp. xylosoxidans to ampicillin, cefazolin, cefuroxime, ceftazidime, cefepime, amoxicillin/carat Retinoic acid, piperacillin/tazobactam, aztreonam, imipenem, gentamicin, tobramycin, amikacin, ciprofloxacin, and levofloxacin were 3/3, 3/3, 3/3, 1/3, 1/3, 1/3, 0/3, 3/3, 2/3, 3/3, 3/3, 3/3, 3/3, and 1/3. ③ Drug resistance of other Gram-positive bacteria: the drug resistance rates of Staphylococcus aureus to penicillin, ampicillin, piperacillin, cefazolin, cefuroxime, cefotaxime, ceftazidime, cefepime, cefoxitin, amoxicillin/carat Retinoic acid, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, aztreonam, imipenem, meropenem, gentamicin, tobramycin, amikacin, tetracycline, tigaricycline, ciprofloxacin, levofloxacin, moxifloxacin, trimethoprim sulfamethoxazole, linezolid, erythromycin, clindamycin, vancomycin, teicoplanin, and rifampin were 2/6, 6/8, 4/5, 4/5, 4/5, 4/5, 4/5, 4/5, 4/5, 4/5, 4/5, 4/5, 4/5, 3/5, 2/5, 2/5, 3/8, 3/5, 3/5, 0/8, 0/8, 3/8, 3/11, 0/5, 1/8, 0/8, 0/8, 2/6, 3/3, 1/3, and 0/3. The drug resistance rates of Streptococcus viridians to penicillin, ampicillin, ceftriaxone, cefoperazone/sulbactam, gentamicin, tetracycline, ciprofloxacin, levofloxacin, moxifloxacin, linezolid, erythromycin, clindamycin, vancomycin, teicoplanin, and rifampin were 3/10, 0/8, 0/7, 0/7, 2/8, 6/10, 0/8, 0/8, 0/7, 0/5, 4/10, 6/10, 0/5, 0/5, and 0/3. The drug resistance rates of β-emolytic streptococcus to antibacterial agents were 0. ④ Drug resistance of complex bacteria. For the 12 patients with double bacterial infection, in the Klebsiella pneumoniae combined with Gram-negative bacteria, the drug resistance rates of Klebsiella pneumoniae to cefotetan, cefoxitin, ampicillin/sulbactam, meropenem, ertapenem, tobramycin, tigecycline, and trimethoprim sulfamethoxazole were 0. The drug resistance rates of Acinetobacter baumannii to ertapenem, levofloxacin, and trimethoprim sulfamethoxazole were 0. The drug resistance rates of Escherichia coli to ceftazidime, cefoxitin, amoxicillin/clavulanic acid, piperacillin/tazobactam, imipenem, meropenem, ertapenem, tobramycin, amikacin, and tigecycline were 0. Citrobacter florida was sensitive to other antibiotics than levofloxacin and trimethoprim cotrimoxazole. In the Escherichia coli combined with Gram-positive bacteria, the drug resistance rates of Escherichia coli to cefotetan, cefepime, cefoxitin, cefoperazone/sulbactam, meropenem, tobramycin, and amikacin were 0. The drug resistance rates of Enterococcus faecalis to penicillin, ampicillin, levofloxacin, moxifloxacin, linezolid, vancomycin, and teicoplanin were 0. The drug resistance rates of Enterococcus casselifavus to ampicillin, tetracycline, levofloxacin, moxifloxacin, linezolid, and erythromycin were 0. The drug resistance rates of Staphylococcus hominis subspecies to levofloxacin, moxifloxacin, linezolid, vancomycin, teicoplanin, and rifampicin were 0. The drug resistance rates of Enterococcus faecium to tetracycline, linezolid, vancomycin, and teicoplanin were 0. In the multiple bacterial infections of Klebsiella pneumoniae + Escherichia coli + Staphylococcus aureus subspecies + Pseudomonas aeruginosa + Torulopsis glabrata, the drug resistance rates of Klebsiella pneumoniae to ceftriaxone, ceftazidime, cefotetan, cefepime, cefoxitin, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, aztreonam, imipenem, tobramycin, amikacin, and levofloxacin were 0. The drug resistance rates of Escherichia coli to ceftazidime, cefotetan, cefepime, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, aztreonam, imipenem, and amikacin were 0. The drug resistance rates of Staphylococcus aureus subspecies to ceftriaxone, ceftazidime, cefotetan, cefepime, ampicillin/sulbactam, piperacillin/tazobactam, cefoperazone/sulbactam, aztreonam, imipenem, tobramycin, amikacin, tigecycline, moxifloxacin, cotrimoxazole, teicoplanin, vancomycin, linezolid, and clindamycin were 0. The drug resistance rates of Pseudomonas aeruginosa to ceftazidime, cefepime, piperacillin/tazobactam, imipenem, gentamicin, tobramycin, amikacin, ciprofloxacin, and levofloxacin were 0. The drug resistance rates of Torulopsis glabrata to 5-fluorocytosine, fluconazole, itraconazole, and voriconazole were 0. In the multiple bacterial infections of Klebsiella pneumoniae + Escherichia coli + Acinetobacter baumannii, the drug resistance rates of Klebsiella pneumoniae to cefotetan, cefepime, piperacillin/tazobactam, imipenem, ertapenem, tobramycin, ciprofloxacin, and levofloxacin were 0. The drug resistance rates of Escherichia coli to amoxicillin/clavulanic acid, piperacillin/tazobactam, imipenem, meropenem were 0. The drug resistance ratets of Acinetobacter baumannii to trimethoprim sulfamethoxazole was 0.@*Conclusions@#Klebsiella pneumoniae is the main pathogen of PLA, followed by Escherichia coli. Klebsiella pneumoniae and Escherichia coli are sensitive to meropenem and tigecycline. Klebsiella pneumoniae subsp. pneumoniae and other Gram-negative bacteria are sensitive to ertapenem. Staphylococcus aureus are sensitive to Linezolid. Antibiotics are selected after drug sensitivity test for patients.