Prebiotic effect of galacto-N-biose on the intestinal lactic acid bacteria as enhancer of acetate production and hypothetical colonization

Galacto-N-biose (GNB) is an important core structure of glycan of mucin glycoproteins in the gastrointestinal (GI) mucosa. Because certain beneficial bacteria inhabiting the GI tract, such as bifidobacteria and lactic acid bacteria, harbor highly specialized GNB metabolic capabilities, GNB is considered a promising prebiotic for nourishing and manipulating beneficial bacteria in the GI tract. However, the precise interactions between GNB and beneficial bacteria and their accompanying health-promoting effects remain elusive. First, we evaluated the proliferative tendency of beneficial bacteria and their production of beneficial metabolites using gut bacterial strains. By comparing the use of GNB, glucose, and inulin as carbon sources, we found that GNB enhanced acetate production in Lacticaseibacillus casei, Lacticaseibacillus rhamnosus, Lactobacillus gasseri, and Lactobacillus johnsonii. The ability of GNB to promote acetate production was also confirmed by RNA-seq analysis, which indicated the upregulation of gene clusters that catalyze the deacetylation of N-acetylgalactosamine-6P and biosynthesize acetyl-CoA from pyruvate, both of which result in acetate production. To explore the in vivo effect of GNB in promoting acetate production, antibiotic-treated BALB/cA mice were administered with GNB with L. rhamnosus, resulting in a fecal acetate content that was 2.7-fold higher than that in mice administered with only L. rhamnosus. Moreover, 2 days after the last administration, a 3.7-fold higher amount of L. rhamnosus was detected in feces administered with GNB with L. rhamnosus than in feces administered with only L. rhamnosus. These findings strongly suggest the prebiotic potential of GNB in enhancing L. rhamnosus colonization and converting L. rhamnosus into higher acetate producers in the GI tract.

IMPORTANCE

Specific members of lactic acid bacteria, which are commonly used as probiotics, possess therapeutic properties that are vital for human health enhancement by producing immunomodulatory metabolites such as exopolysaccharides, short-chain fatty acids, and bacteriocins. The long residence time of probiotic lactic acid bacteria in the GI tract prolongs their beneficial health effects. Moreover, the colonization property is also desirable for the application of probiotics in mucosal vaccination to provoke a local immune response. In this study, we found that GNB could enhance the beneficial properties of intestinal lactic acid bacteria that inhabit the human GI tract, stimulating acetate production and promoting intestinal colonization. Our findings provide a rationale for the addition of GNB to lactic acid bacteria-based functional foods. This has also led to the development of therapeutics supported by more rational prebiotic and probiotic selection, leading to an improved healthy lifestyle for humans.

Comparison of the popliteal artery and the capsule of the posterior knee (IPACK) block and the genicular nerve block in primary total knee arthroplasty: A prospective randomized trial

OBJECTIVES

To compare the efficacy of genicular block and interspace between the popliteal artery and the posterior capsule (IPACK) block in the reduction of postoperative pain, the need for rescue analgesics, and the effects on a range of motion (ROM) in patients with TKA.

METHODS

This prospective randomized controlled study was carried out between February and May 2023. Based on the block method, 60 participants were divided into three equal groups. These groups included the IPACK block group (n=20), the genicular block group (n=20), and control group (n=20). Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Society score (KSS) and Oxford Knee score (OKS) were used for clinical evaluation in the postoperative period.

RESULTS

The KSS and OKS scores of the IPACK and GNB were significantly lower than the control group (p<0.001, p<0.001). The timed up and go (TUG) values of the IPACK and GNB groups at 12th and 24th hour were significantly lower than the control group (p<0.001, p<0.001). The Tramadol rescue values of the IPACK block and control groups were significantly higher than the GNB group (p=0.028, p=0.001, respectively). The ROM values of the IPACK and GNB groups were significantly higher than the control group (p<0.001, p<0.001).

CONCLUSION

Both GNB and IPACK blocks had a significant positive impact on postoperative pain scores within the initial 24 hours following total knee arthroplasty (TKA). In comparison with IPACK, GNB had lower opioid consumption in the early postoperative period while also promoting better mobilization.

Incidence of catheter-associated urinary tract infections by Gram-negative bacilli and their ESBL and carbapenemase production in specialized hospitals of Bahir Dar, northwest Ethiopia

BACKGROUND

Catheter-associated urinary tract infections (CAUTIs) due to multidrug-resistant Gram-negative bacilli (GNB) is a common concern globally. Investigating the incidence of CAUTI and associated antibiotic resistance has paramount importance from the health care associated infections perspective. This study therefore assessed the incidence of CAUTIs due to GNB and the production of extended-spectrum beta-lactamase (ESBL) and carbapenemase among inpatients in specialized hospitals of Northwest, Ethiopia.

METHODS

A total of 363 patients with indwelling urinary catheters who were admitted in the hospital for > 48 h were consecutively enrolled and followed from 3 to 18 days. Data were collected through interviewing and review of medical records. Patients who developed at least one of the following: fever (> 38 OC), suprapubic tenderness, or costovertebral angle pain, coupled with a GNB positive urine culture of ≥ 103 CFU/mL with no more than two bacterial species were defined as CAUTI. The ESBL and carbapenemase production were detected and identified by chromogenic medium. Logistic regression analysis was done to identify associated factors.

RESULTS

From 363 patients followed, the incidence rate of CAUTI was 27.8 per 1000 catheter days. Catheterization for ≥ 8 days (AOR = 10.6, 95%CI:1.8-62.1) and hospitalization for > 10 days (AOR = 8.1, 95%CI: 2.4-27.2) were the factors significantly associated with CAUTIs. E. coli (n = 18, 34.6%), Proteus species (n = 7, 13.5%), and P. aeruginosa (n = 6, 11.5%) were the most frequent GNB. Isolates revealed high rates of resistance to amoxicillin-clavulanic acid (100%), cefazolin (n = 51, 98%), ceftazidime (n = 47, 90%) and cefotaxime (n = 46, 88%). Most of the GNB isolates (86.5%) were multidrug-resistant. Overall, 19.2% and 5.8% of GNB isolates were ESBL and carbapenemase producers, respectively.

CONCLUSIONS

Incidence of CAUTI with Gram-negative bacilli is high. As most of the GNB isolates are MDR and showed a super high rate of resistance to amoxicillin-clavulanic and third-generation cephalosporins, empirical treatment with these substances is virtually ineffective in patients with suspected GNB infection in Ethiopia. The expression of ESBL and carbapenemase among GNB isolates is also a concern. Therefore, improved infection prevention and control measures, careful use of catheters and third generation of cephalosporins are needed to improve patient outcomes and reduce the burden of CAUTIs and the spreading of antimicrobial resistance.

Evaluating antibiotic therapy for ventilator-associated pneumonia caused by gram-negative bacilli

Introduction

Ventilator-associated pneumonias (VAPs) are a complication of mechanical ventilation in the intensive care unit (ICU) that increase length of stay, morbidity, and mortality. While identifying and treating infections early is paramount to improving patient outcomes, more and more data demonstrate limited courses of antibiotics improve outcomes. Prolonged (10-14 day) courses of antibiotics have remained the standard of care for pneumonia due to gram-negative bacilli (GNR). We aimed to review our GNR VAPs to assess risk factors for recurrent GNR infections.

Methods

We reviewed trauma patients who developed VAP from 02/2019 through 05/2022. Demographics, injury characteristics, and outcomes were reviewed with a focus on pneumonia details including the cultured pathogen(s), antibiotic(s) used, treatment duration, and presence of recurrent infections. We then compared single episode VAPs to multiple episode VAPs among patients infected by GNRs.

Results

Eleven of the fifty trauma patients admitted to the ICU suffered a VAP caused by a GNR. Of these eleven patients, six experienced a recurrent infection, four of which were caused by Pseudomonas aeruginosa and two of which were caused by Enterobacter aerogenes. Among the patients who received ten days of antibiotic treatment, half suffered a recurrence. Although, there was no difference in the microbiology or antibiotic duration between the recurrences and single episodes.

Conclusion

Despite prolonged use of antibiotics, we found that the risk of recurrent or persistent infections was high among patients with VAP due to GNB. Further study is needed to determine optimal treatment to minimize the risk of these recurrences.

Key message

Ventilator-associated pneumonia due to gram-negative bacilli is a rare but high morbidity complication in intensive care units. Despite prolonged duration of therapy, these infections still appear to account for many recurrent infections and further study into optimal therapy is warranted.

Comparing the diagnostic value of 18F-FDG PET/CT scan and bone marrow biopsy in newly diagnosed pediatric neuroblastoma and ganglioneuroblastoma

Objective

This study aims to compare the diagnostic value of ¹⁸F-fluorodeoxyglucose (18-FDG) positron emission tomography (PET)/computed tomography (CT) (¹⁸F-FDG PET/CT) scan and bone marrow biopsy (BMB) for evaluating bone marrow infiltration (BMI) in newly diagnosed pediatric neuroblastoma (NB) and ganglioneuroblastoma (GNB).

Methods

We retrospectively reviewed 51 patients with newly diagnosed NB and GNB between June 1, 2019 and May 31, 2022. Each patient had undergone ¹⁸F-FDG PET/CT and BMB within 1 week and received no treatment. Clinical data were collected and statistically analyzed, including age, sex, pathologic type, and laboratory parameters. ¹⁸F-FDG PET/CT and BMB revealed the result of bone lesions.

Results

A concordance analysis showed that, in this study population, ¹⁸F-FDG PET/CT and BMB were in moderate agreement (Cohen's Kappa = 0.444; p = 0.001), with an absolute agreement consistency of 72.5% (37 of 51). The analysis of the receiver operating characteristic (ROC) curve determined that the areas under the ROC curve (AUCs) of SUV_BM and SUV/HE-SUVmax were 0.971 (95% CI: 0.911-1.000; p < 0.001) and 0.917 (95% CI: 0.715-1.000; p < 0.001) to predict bone-bone marrow involvement (BMI), respectively.

Conclusion

¹⁸F-FDG PET/CT detects BMI with good diagnostic accuracy and can reduce unnecessary invasive inspections in newly diagnosed pediatric NB and GNB, especially patterns C and D. The analysis of the semi-quantitative uptake of ¹⁸F-FDG, including SUV_BM and SUV_BM/HE-SUVmax, enables an effective differentiation between patterns A and B.

Comparative evaluation of colistin susceptibility testing by Disk Diffusion and Broth Microdilution methods: An experience from a tertiary care hospital

BACKGROUND

Recent times have seen uninhibited use of colistin due to emergence of carbapenem resistant gram-negative bacteria especially in India and the most common method still employed by most of the laboratories for in vitro testing of colistin is disk diffusion method.

OBJECTIVE

The study aimed to compare two methods for colistin susceptibility testing Methods: This retrospective observational study was done on a total of 212 non-duplicate carbapenem resistant gram-negative isolates from patients attending our tertiary care hospital from April 2019 to June 2020. Colistin susceptibility testing for these isolates was done by disk diffusion method followed by broth microdilution method.

RESULTS

We found out that disk diffusion method showed relatively low sensitivity [34.5%; 95%CI: 19.94-52.65] but high specificity [99.45%; 95% CI: 96.97 - 99.90] in detecting colistin resistant organisms in comparison to broth microdilution method.

CONCLUSION

Disk diffusion method is an unreliable method at detecting colistin resistance. Therefore, we should always rely on susceptibility testing by standard broth microdilution or newly introduced broth disk elution method before dispatching the report even in resource limited settings. The early and accurate reporting of susceptibility results can preserve the therapeutic value of the drug until we have newer treatment options available in the country.

Extended-Spectrum β-Lactamase and Carbapenemase Producing Gram-Negative Bacilli Infections Among Patients in Intensive Care Units of Felegehiwot Referral Hospital: A Prospective Cross-Sectional Study

Background

Owing to the specific risk profile of its residents, intensive care units (ICUs) are the best place for selection pressure and the epicenter for resistance development and dissemination. Infections with β-lactamase releasing Gram-negative bacilli (GNB) at ICUs are an emerging global threat. This study dogged the magnitude of extended-spectrum β-lactamase (ESBL) and carbapenemase releasing Gram-negative bacilli infections and associated factors among patients in the ICUs of Felegehiwot Referral Hospital, Ethiopia.

Methods

A cross-sectional study was done through February to June 2020. Wound swabs, urine, blood and sputum samples were collected from patients in the ICUs symptomatic for infections while excluding those under coma and shock. Bacterial species were verified using standard microbiological methods. Carbapenemase and ESBL production were identified using modified carbapenem inactivation and combined disk diffusion methods, respectively. Multivariable analysis was calculated for factors associated with ESBL production. P-value < 0.05 was taken as cut-off for statistical significance.

Results

Out of 270 patients in the ICU, 67 (24.8%) and 14 (5.2%) had infections with ESBL and carbapenemase releasing GNB, respectively. The most frequent ESBL producing isolates were P. aeruginosa (100%), E. cloacae (100%), K. pneumoniae (82.8%) and E. coli (64%). The predominant carbapenemase producer isolates were K. pneumoniae (27.6%) and E. cloacae (33.3%). Overall, 77 (81.1%) of species were multi-drug resistant. All GNB species were 100% resistant to tetracycline and ampicillin. They are also resistant to cefuroxime, ceftazidime, sulfamethoxazole-trimethoprim and cefotaxime. Prior hospitalization (AOR = 5.5, CI = 2.63-11.46), support with medical care devices (AOR = 23.7, CI = 4.6-12) and arterial intravenous catheterization (AOR = 2.7, CI = 1.3-5.3) had significant association with β-lactamase producing GNB infection.

Conclusion

Infection with ESBL and carbapenemase producing Gram-negative bacilli linked with an alarming degree of multi-drug resistant isolates is a major healthcare threat among patients in ICUs. Hence, strict adherence to infection prevention practices and wise use of antibiotics are recommended to slow the spread of antimicrobial resistance.

Ventilator-associated pneumonia due to Stenotrophomonas maltophilia: Risk factors and outcome

BACKGROUND

Stenotrophomonas maltophilia (SM) is increasingly identified in intensive care unit (ICU). This study aim to identify risk factors for SM ventilator-associated pneumonia (VAP) and whether it affects ICU mortality METHODS: Two nested matched case-control studies were performed based in OUTCOMEREA database. The first episodes of SM-VAP patients were matched with two different control groups: VAP due to other micro-organisms (VAP-other) and Pseudomonas aeruginosa VAP (Pyo-VAP). Matching criteria were the hospital, the SAPS II, and the previous duration of mechanical ventilation (MV).

RESULTS

Of the 102 SM-VAP patients (6.2% of all VAP patients), 92 were matched with 375 controls for the SM-VAP/other-VAP matching and 84 with 237 controls for the SM-VAP/Pyo-VAP matching. SM-VAP risk factors were an exposition to ureido/carboxypenicillin or carbapenem during the week before VAP, and respiratory and coagulation components of SOFA score upper to 2 before VAP. SM-VAP received early adequate therapy in 70 cases (68.6%). Risk factors for Day-30 were age (OR = 1.03; p < 0.01) and Chronic heart failure (OR = 3.15; p < 0.01). Adequate treatment, either monotherapy or combination of antimicrobials, did not modify mortality. There was no difference in 30-day mortality, but 60-day mortality was higher in patients with SM-VAP compared to Other-VAP (P = 0.056).

CONCLUSIONS

In a large series, independent risk factors for the SM-VAP were ureido/carboxypenicillin or carbapenem exposure the week before VAP, and respiratory and coagulation components of the SOFA score > 2 before VAP. Mortality risk factors of SM-VAP were age and chronic heart failure. Adequate treatment did not improve SM-VAP prognosis.

Galacto-N-biose is neuroprotective against glutamate-induced excitotoxicity in vitro

Galacto-N-biose (GNB: Galβ1-3GalNAc) is an O-glycan disaccharide core moiety that is a core component of mucin in the gastrointestinal tract; however, the physiological properties of GNB are not well understood. Glutamate excitotoxicity causes neuronal death in acute neurological disorders including stroke, trauma, and neurodegenerative disease. Therefore the discovery of drugs to treat glutamate excitotoxicity is an important goal. Here, we report that GNB is neuroprotective against glutamate-induced excitotoxicity. We treated 14-15 days in vitro cultured rat cortical neurons with 0.1-1000nM GNB together with 30µm glutamate for various durations. Short-term (3h) GNB treatments showed a modest neuroprotective effect against glutamate neurotoxicity, however, long-term (24h) GNB treatment conferred significant neuroprotective effects, as shown by both MTT and immunocytochemical assays. Prolonged GNB treatment did not alter glutamate-induced calcium influx, but did induce antioxidant-related gene expression. Furthermore, GNB treatment did not induce cell death or alter synaptic connections. These data suggest that GNB is a potential candidate drug that protects against glutamate excitotoxicity without affecting cell viability and synaptic connections.

GNB2 is a mediator of lidocaine-induced apoptosis in rat pheochromocytoma PC12 cells

Lidocaine has been recognized to induce neurotoxicity. However, the molecular mechanism underlying this effect, especially the critical molecules in cells that mediated the lidocaine-induced apoptosis were unclear. In the present study, PC12 cells were administrated with lidocaine for 48h. Using MTT assay and flow cytometry, we found lidocaine significantly decreased the cell proliferation and S phases in PC12 cells with treatment concentrations, and significantly enhanced cell apoptosis with treatment concentrations. Two-dimensional gel electrophoresis (2-DE) analysis and LC-MS/MS were used to identification of protein biomarkers. Six proteins were identified. Among them, three were up-expressed including ANXA6, GNB2 and STMN1, other three were down-expressed including ubiquitin-linke protein 7 (UBL7), DDAH2 and BLVRB. Using qRT-PCR, we confirmed that lidocaine up-regulated the mRNA expression of STMN1, GNB2, ANXA6 and DDAH2, and found that the GNB2 had the largest change (about increased by 6.4 folds). The up-regulation of GNB2 by lidocaine was also validated by western blot. After transfected with 100μM GNB2-Rat-453 siRNA, the expression of GNB2 in PC12 cells was almost completely inhibited; and the cell proliferation and cells in S phases were significantly enhanced, cell apoptosis including both early apoptosis and later apoptosis were significantly reduced in the presence of 0.5mM lidocaine for 48h. Therefore, neuronal apoptosis was induced by lidocaine and this effect was mediated by GNB2. Further research is needed to assess the clinical relevance and exact mechanism of neuronal apoptosis caused by lidocaine.