Reduction effect of bacterial counts by preoperative saline lavage of the stomach in performing laparoscopic and endoscopic cooperative surgery

AIM: To investigate the effects of gastric lavage with 2000 mL of saline in laparoscopic and endoscopic cooperative surgery.

A study of the efficacy of bacterial biofilm cleanout for gastrointestinal endoscopes

AIM:To compare the influence and clearance effect of enzymatic and non-enzymatic detergents against Escherichia coli (E. coli) biofilm on the inner surface of gastroscopes.METHODS:Teflon tubes were incubated in a mixture of different detergents and E. coli culture (106 CFU/mL) for 72 h at 15℃,and biofilms on the inner surface of the teflon tubes were analyzed by bacterial count and scanning electron microscopy. To evaluate the clear-ance effect of detergents,after biofilms were formed on the inner surface of Teflon tubes by 72 h lavage with E. coli culture,tubes were lavaged by enzymatic and non-enzymatic detergents at a speed of 250 mL/min,then biofilms on the inner surface were analyzed by bacterial count and scanning electron microscopy.RESULTS:Non-enzymatic detergent had a better inhi-bition function on biofilm formation than enzymatic de-tergent as it reduced bacterial burden by 2.4 log compared with the control samples (P = 0.00). Inhibition function of enzymatic detergent was not significantly different to that of control samples and reduced bac-terial burden by 0.2 log on average (P > 0.05). After lavaging at 250 mL/min for 3 min,no living bacteria were left in the tubes. Scanning electron microscopy observation showed biofi lms became very loose by the high shear force effect. CONCLUSION:Non-enzymatic detergent has a better inhibition effect on biofilm formation at room temperature. High speed pre-lavage and detergents are very important in temporal formed biofilm elimination.

Correlations among core species corresponding to the clinical staging of periodontitis

The correlation between microbiota plays a vital role in the progression of periodontal disease.This study investigated the in situ interaction networks between periodontal pathogens in periodontal and peri-implant disease.We used quantitative real-time polymerase chain reaction and Pearson’s correlation coefficients to quantify the copy numbers and correlations of four oral core species—Fusobacterium nucleatum,Porphyromonas gingivalis,Prevotella intermedia,and Streptococcus gordonii—from 80 subgingival sites(healthy and with periodontitis or gingivitis)in patients with periodontitis,and 68 subgingival sites(healthy and with periodontitis,gingivitis,peri-implantitis,or peri-implant mucositis)in patients with implants.The highest bacterial counts were observed for Porphyromonas gingivalis and Prevotella intermedia at all the sites.Within the same cohorts,the bacterial loads were greater at diseased sites than at healthy sites.Bacterial counts did not differ among clinical sites in the same group(P>0.05)but differed between periodontitis and peri-implant mucositis sites in the two groups.Porphyromonas gingivalis,F.nucleatum,and Prevotella intermedia had strong correlations at gingivitis and healthy sites and moderate correlations at periodontitis sites in patients with periodontitis.In patients with implants,Prevotella intermedia,F.nucleatum,and S.gordonii had strong correlations only at peri-implantitis sites.Also,based on metagenomic analysis,F.nucleatum and Prevotella intermedia were significantly correlated at the subgingival plaque in peri-implantitis and periodontitis samples.Our results suggest that variations in microbe-microbe interactions in subgingival plaque reflect changes in the progression of periodontal disease,providing a new perspective for understanding the mechanisms of periodontitis and peri-implantitis.

Microbiological Quality of Freshly Prepared, Packaged Fruit and Milk Juices Sold in Cafés, Shops, and Supermarkets in Hargeisa, Somaliland

Background: Due to their delicious taste, high nutritional content, and health benefits, fruit juices are well-known drinks in many countries and are now an essential component of the modern diet. Objective: Determining the microbiological quality of both packaged and freshly made fruit and milk juices. Method: The spread-plate approach was employed to isolate and count the bacteria. 90 ml of sterile peptone water were blended with 10 ml of well-mixed, packed, and freshly made fruit juices. The samples were sequentially diluted (101 - 105) in accordance with the Indian Manual of Food Microbiological Testing Methods. Results: From eight samples of imported packaged fruit and milk juice, the average of total coliform, staphylococci, and viable bacterial counts were zero, 1.39 × 102, and 2 × 102 CFU/ml, respectively. In contrast, from three samples of locally produced fruit and milk juice, the average of total coliform, staphylococci, and viable bacterial counts were zero, 5.83 × 102, and 2.73 × 103 CFU/ml, respectively. Four samples of handmade prepared fruit and milk juices had a mean of total coliform, staphylococci, and viable bacterial count of 1.441 × 104, 4.1 × 103, and 2.35 × 105 CFU/ml, respectively. Conclusion: 33.3% of the results from microbiological analysis of freshly made fruit and milk juices met the permissible range of the Revised Microbiological Standards for Fruit and Vegetables and Their Products, which were published in 2018 and as well as the Hong Kong Center for Food Safety, whereas 66.7% of the microbiological analyses of freshly prepared fruit and milk juices were above the permissible reference range of GSO standard 2000. 12.5% of the investigated imported and packed fruits and milk juices had one failed test (TSC), which was above the acceptable limit, 87.5% of the tested samples of fruit and milk juices fulfilled the necessary standards of TCC, TVBC, and TSC. 100% of the tested locally manufactured fruit and milk juices complied with TSC, TCC, and TVBC requirements. All investigations showed that freshly made fruit and milk juices were heavily contaminated (Total viable bacterial count, total coliform count, and total staphylococcus count). .

Evaluation of Mastitis Related Measures ＆ Their Applications to Classify Buffalo Milk in Chitwan, Nepal

A study was performed to evaluate the epidemiological aspects of buffalo mastitis in the District Chitwan, Nepal for characterizing the California mastitis test （CMT）, somatic cell count （SCC）, electrical conductivity （EC） values and bacteriological analysis for defining buffalo milk. The CMT was performed by mixing equal volume of milk and 3% sodium lauryl sulphate. The SCC was determined by staining milk film with New Man’s Lampert Stain and EC values were measured by manual digital mastitis detector and expressed as mS/cm. Bacteriological analysis was done on the basis of Gram’s stain, morphological findings, colony characteristics and biochemical tests. The maximum number （16%） of clinical cases of mastitis was observed in the month of July and lowest in the month of April （1.6%）. When the temperature and humidity increased, it indicates that there is need for better care of lactating buffaloes during this month. On a quarter basis, 16% of the foremilk samples in buffaloes were diagnosed as having subclinical mastitis and 11% were diagnosed as having clinical mastitis. The results of CMT scores and SCC showed the evidence that subclinical and clinical mastitic milk was having CMT positive scores （＋1~＋3） with ≥ 200 × 103 cells/mL. The mean pH of clinically normal buffalo milk was 6.75 （range 6.39 to 7.08） and subclinical mastitic and clinical mastitic milk was 6.85 （range 6.37 to 7.10） and 6.88 （range 6.41 to 7.20）, respectively. Analysis of EC value in the milk revealed the presence of mastitis in buffaloes and the cut-off values was 3.7 mS/cm. The coagulase negative Staphylococcus （CNS）, such as S. albus and S. epidermidis were the predominant organisms associated with subclinical mastitis, and CNS and coliforms in clinical mastitis. This information suggests that environmental mastitis was prevalent in buffaloes of Chitwan District. In this study, 9.5% of the quarters were having bacterial count （BC） more than 250 cfu/mL. The proposed criteria for normal milk are absence of clinical signs, CMT negative, SCC 〈 200 × 10^3 cells/mL, EC 〈 3.7 mS/cm and 〈 250 cfu/mL bacteria. The parameters for defining subclinically mastitic milk are absence of clinical signs, CMT positive, SCC ≥ 200 × 10^3 cells/mL, EC 〉 3.7 mS/cm and 〉 250 cfu/mL bacteria. Similarly, clinical mastitic milk was defined as milk having presence of clinical signs, CMT positive, SCC ≥ 200 × 10^3 cells /mL, EC 〉 3.7 mS/cm and BC 〉 250 cfu/mL.

Characterization of bacterial community dynamics in a full-scale drinking water treatment plant

Understanding the spatial and temporal dynamics of microbial communities in drinking water systems is vital to securing the microbial safety of drinking water.The objective of this study was to comprehensively characterize the dynamics of microbial biomass and bacterial communities at each step of a full-scale drinking water treatment plant in Beijing,China.Both bulk water and biofilm samples on granular activated carbon（GAC） were collected over 9 months.The proportion of cultivable cells decreased during the treatment processes,and this proportion was higher in warm season than cool season,suggesting that treatment processes and water temperature probably had considerable impact on the R2 A cultivability of total bacteria.16 s rRNA gene based 454 pyrosequencing analysis of the bacterial community revealed that Proteobacteria predominated in all samples.The GAC biofilm harbored a distinct population with a much higher relative abundance of Acidobactena than water samples.Principle coordinate analysis and one-way analysis of similarity indicated that the dynamics of the microbial communities in bulk water and biofilm samples were better explained by the treatment processes rather than by sampling time,and distinctive changes of the microbial communities in water occurred after GAC filtration.Furthermore,20 distinct OTUs contributing most to the dissimilarity among samples of different sampling locations and 6 persistent OTUs present in the entire treatment process flow were identified.Overall,our findings demonstrate the significant effects that treatment processes have on the microbial biomass and community fluctuation and provide implications for further targeted investigation on particular bacteria populations.

Applications and challenges for single-bacteria analysis by flow cytometry

Flow cytometry(FCM)is a powerful technique for single-bacteria analysis via simultaneous light-scattering and fluorescence measurements.By offering high-throughput,quantitative,and multiparameter analysis at the single-cell level,FCM has gained an increased popularity in microbiological research,food safety monitoring,water quality control,and clinical diagnosis.Here we will review the recent applications of flow cytometry in areas such as(1)total bacterial cell count,(2)bacterial viability analysis,(3)specific bacterial detection and identification,(4)characterization of physiological changes under environmental perturbations,and(5)biological function studies.Nevertheless,despite these widespread applications,challenges still remain for the detection of small sizes of bacteria and biochemical features that cannot be brightly stained via fluorescence.Recent improvement in FCM instrumentation will be discussed,and particularly the development of high sensitivity flow cytometry for advanced analysis of single bacterial cells will be highlighted.