Probiotics: truths and illusions Tavanaeian, Sogol; Feizabadi, Mohammad Mehdi
Iranian journal of microbiology,
02/2024, Letnik:
16, Številka:
1
Journal Article
Enterotoxigenic
(ETBF) produces
toxin (BFT), which is associated with acute diarrheal, inflammatory bowel disease, and colorectal cancer (CRC). In experimental models, ETBF has been shown to ...contribute to colon carcinogenesis. The present study was conducted to investigate mucosal colonization of ETBF in the colon to find a possible association between the presence of ETBF and precancerous and cancerous lesions. The mucosal biopsies of involved sites were obtained from 68 patients with precancerous and cancerous lesions and 52 healthy controls (HC). The samples were cultured on Bacteroides Bile Esculin agar. Then, specific primers were designed to detect
and
gene using quantitative real-time PCR, and the possible links of ETBF with clinicopathological characteristics was evaluated. Also real-time PCR was performed to detect the
gene subtypes.
was detected in 51% of the patients and 48% of HCs cultures. The 16SrRNA gene was found to be present in 63 and 81% of the patients and HCs' samples, respectively. Moreover, the
gene was detected in 47 and 3.8% of the patients and HCs, respectively. Also,
was significantly more abundant in the patients' samples compared to those of HCs. In the patient group, higher odds ratio (OR) of ETBF was significantly associated with serrated lesions and adenoma with low-grade dysplasia. The
gene was the most prevalent subtype of
, followed by the
gene. This was the first study in Iran to demonstrate increased positivity of ETBF in patients with precancerous and cancerous lesions. In this study, the
gene was found to be associated with CRC, especially in the patients with precancerous lesions and initial carcinogenic lesions. Moreover, the results suggest that mucosal BFT exposure is common and could be a risk factor and a screening marker for developing CRC.
Background The emergence of healthcare-associated infections (HAIs) or superinfections in COVID-19 patients has resulted in poor prognosis and increased mortality. Methods In a cross-sectional study, ...101 respiratory samples were collected from ICU-admitted COVID-19 patients. The HAI rate, demographics, and antibiotic resistance were assessed. Results The HAI rate was 83.16% (76.62% bacterial and 6.54% fungal). The prevalence of 3 major HAI-causing organisms included Klebsiella pneumoniae (41.5%), Acinetobacter baumannii (20.8%), and Staphylococcus aureus (4.9%). Mortality and intubation ventilation proportions of 90% (p = 0.027) and 92.2% (p = 0.02) were significant among patients with superinfection, respectively. Multiple logistic regression analysis showed SpO.sub.2 pressure (odds ratio 0.842; 95% CI 0.750-0.945; p = 0.004) as a predictive factor in the association between antibiotic usage and mortality. More than 50% of patients received carbapenems. The resistance rates to at least one antibiotic of third-generation cephalosporins, aminoglycosides, quinolones/fluoroquinolones, tetracyclines, and beta-lactam inhibitors were 95.2%, 95.2%, 90%, 57.1%, and 100% among A. baumannii isolates and 71.4%, 55%, 69%, 61.9%, and 59.5% among K. pneumoniae isolates, respectively. A proportion of 60% was recorded for methicillin-resistant S. aureus isolates. Conclusion As a result, antibiotic treatment should be administered following the microbial resistance profile. Contact isolation and infection control measures should be implemented as needed. Keywords: Healthcare-associated infections, Superinfection, COVID-19, Antibiotic resistance, Respiratory infections
Colorectal cancer (CRC) is the third leading cause of cancer, and presents a considerable disease burden, worldwide. Recently, the gut microbiota has been proposed as a potential risk factor for CRC, ...and even adenomatous polyps (AP). Here, the aim of this study was to investigate the role of selected gut bacteria as fecal bacterial biomarkers, in early detection of CRC and AP.
Fecal samples (n = 93) were collected from Taleghani Hospital, Tehran, Iran, between 2015 and 2017, from normal controls (NC), AP cases and CRC stage I patients, who were undergoing screening for colonoscopy. Absolute quantitative real time PCR (qPCR) assays were established for the quantification of bacterial marker candidates, in all cases and control groups. In order to evaluate the diagnostic value of bacterial candidates in distinguishing CRC from a polyp, receiver operating characteristic curve (ROC) was performed. Multiple logistic regressions were used to find the best combinations of the bacterial candidates, then, combinations were analyzed based on three methods, including linear combination, multiple logistic and factor analysis models.
According to the logistic model, combination of Fusobacterium nucleatum, Enterococcus feacalis, Streptococcus bovis, Enterotoxigenic Bacteroides fragilis (ETBF) and Porphyromonas spp. showed improved diagnostic performance, compared to each bacterium alone, as area under the receiver operating characteristic (AUROC) increases to 0.97, with 95% confidence interval. It was found that a simple linear combination was an appropriate model for discriminating AP and CRC cases, compared to the NC, with a sensitivity of 91.4% and specificity of 93.5%.
Our results indicated that based on fecal bacterial candidates, statistical simple linear combination model and ROC curve analysis, early detection of AP and CRC might be possible.
•Fecal bacteria was evaluated regarding colon cancer (CRC) early detection.•Quantitative real time PCR (qPCR) assays were established for quantification.•Multiple logistic regressions were applied to find the best combinations.•The combinations were analyzed to find best sensitivity and specificity.•Based on fecal bacteria, CRC early detection might be possible.
Abstract
Background
Streptococcus pneumoniae
causes serious infections worldwide. The aim of this study was to determine the molecular characteristic, antibiotic resistance pattern and capsular types ...of invasive
S. pneumoniae
in Tehran, Iran.
Results
Of the 44 pneumococcal invasive isolates, 39 (89%) were isolated from children and 5 (11%) from adults. The results show that all pneumococcal isolates were susceptible to linezolid but had varying resistance to trimethoprim-sulfamethoxazole (86%), erythromycin (73%), tetracycline (66%), clindamycin (43%), penicillin (16%), chloramphenicol (14%) and levofloxacin (2%). The range of erythromycin, tetracycline and penicillin MICs were 2 - ≥ 256 μg/mL, 4 - ≥ 48 μg/mL, and 0.047 - ≥ 256 respectively. All of the penicillin resistant isolates were multidrug resistant (MDR) and in addition to penicillin were resistant to tetracycline, erythromycin and trimethoprim-sulfamethoxazole. The most common capsular types detected in 64% of the pneumococcal isolates was 6A/B, 19A, 15A, 23F. The multilocus sequence typing (MLST) of 10 pneumococcal isolates revealed 9 different sequence types (STs), including ST 15139 (capsular type 19A) and ST 15140 (capsular type 23F), which have not previously been reported.
Conclusions
The study revealed that the
S. pneumoniae
isolates belonged to diverse capsular types and clones with high rate of resistance to erythromycin, tetracycline, and penicillin.
sequence type 131 (ST131) is associated with extended-spectrum beta-lactamase (ESBL) production and fluoroquinolone resistance. This study aimed to investigate the prevalence of ST131, ESBL, and ...plasmid-mediated quinolone resistance (PMQR) genes in the ciprofloxacin-resistant (CIP
) and ESBL producers from women with UTI.
The CIP-resistant ESBL producing (CIP
/ESBL
)
isolates were screened for ST131-by specific PCR of
and
. The ESBL and PMQR genes were screened by single PCR. The ST131 and non-ST131 isolates were selected to determine the mutations of
and
using PCR and sequencing, and also their genetic background by the Pasteur-MLST scheme.
Overall, 55% (33/60) CIP
/ESBL
isolates were identified as ST131 (94% O25b-ST131). Resistance rate to ampicillin-sulbactam (70%), aztreonam (97%) and gentamicin (61%), the prevalence of
(66%),
(82%), the profile of
(30%), and the double mutation in the
was significantly higher in ST131 than non- ST131 isolates. The coexistence of PMQR and ESBL genes was found in more than 50% of ST131 and non-ST131 isolates. ST131 isolates differentiated into PST43 and PST506.
Management of women with UTI caused by the CIP
/ESBL
isolates (ST131) co-harbored PMQR, ESBL, and chromosomal mutations, is important for their effective therapy.
Bacteroides fragilis is a part of the normal gastrointestinal flora, but it is also the most common anaerobic bacteria causing the infection. It is highly resistant to antibiotics and contains ...abundant antibiotic resistance mechanisms.
The antibiotic resistance pattern of 78 isolates of B. fragilis (22 strains from clinical samples and 56 strains from the colorectal tissue) was investigated using agar dilution method. The gene encoding Bacteroides fargilis toxin bft, and antibiotic resistance genes were targeted by PCR assay.
The highest rate of resistance was observed for penicillin G (100%) followed by tetracycline (74.4%), clindamycin (41%) and cefoxitin (38.5%). Only a single isolate showed resistance to imipenem which contained cfiA and IS1186 genes. All isolates were susceptible to metronidazole. Accordingly, tetQ (87.2%), cepA (73.1%) and ermF (64.1%) were the most abundant antibiotic-resistant genes identified in this study. MIC values for penicillin, cefoxitin and clindamycin were significantly different among isolates with the cepA, cfxA and ermF in compare with those lacking such genes. In addition, 22.7 and 17.8% of clinical and GIT isolates had the bft gene, respectively.
The finding of this study shows that metronidazole is highly in vitro active agent against all of B. fragilis isolates and remain the first-line antimicrobial for empirical therapy.
The majority of all kidney stone cases are oxalate urolithiasis with a high risk of recurrence. Beside its widespread occurrence, kidney stones are characterized by severe complications and high ...treatment costs. Probiotics and herbal medications could be forthcoming therapeutic interventions in the management of oxalate kidney stones.
The PubMed/MEDLINE database was searched for keywords "
" AND "Oxalate" OR "oxalate degradation" AND "
" OR "
" OR "recombinant
" OR "
", and "
" AND "herbal extract". The search returned 253 results, 38 of which were included in the review.
Most of the oxalate-degrading probiotics belong to the
and
genus with a minimum dosage of 10
CFU in the form of capsules, sachets, and lyophilized powder. Oxalate concentration in media was 5-50mM with an incubation time ranging from 24h to 14 days. The majority of the studies suggested that probiotic supplementation might be useful for reducing urinary excretion of oxalate and urea and alleviation of stone formation. Different herbal extracts were used on murine models of nephrolithiasis (induced by 0.5-3% ethylene glycol) with reduction of renal inflammation and urinary parameters, and calcium oxalate crystals.
Several strains of probiotics and herbal extracts confer protective effects against kidney stone/nephrolithiasis, indicating their promising nature for being considered as elements of preventive / adjuvant therapeutic strategies.
Alterations of the gut microbiome in cases of colorectal cancer (CRC) hint at the involvement of host-microbe interactions in the onset and progression of CRC and also, possibly, provide novel ways ...to detect and prevent CRC early. The aim of the present study was to evaluate whether the oral and fecal microbiomes of an individual can be suitable for CRC screening. Oral and fecal samples (
= 80) were gathered in Taleghani hospital, affiliated with Shahid Beheshti University of Medical Sciences, Tehran-Iran, from CRC stage 0 and I patients and healthy controls (HCs), who were screened for the first time. Microbial metagenomics assays were performed for studying microbiota profiles in all oral and fecal samples gathered. An abundance of top bacterial genera from both types of specimens (fecal and saliva samples) revealed a distinction between CRC patients and HCs. In saliva samples, the α diversity index was different between the microbiome of HCs and CRC patients, while β diversity showed a densely clustered microbiome in the HCs but a more dispersed pattern in CRC cases. The α and β diversity of fecal microbiota between HCs and CRC patients showed no statistically significant differences.
was identified as a potential bacterial biomarker in CRC saliva samples, while
,
,
,
,
, and
were ideal to distinguish HCs from CRC patients. One of the reasons for the heterogeneity of CRC may be the gastrointestinal (GI) tract microbiota, which can also cause systematic resistance to CRC. Moreover, an evaluation of saliva microbiota might offer a suitable screening test for the early detection of this malignancy, providing more accurate results than its fecal counterpart.
Colorectal cancer (CRC) poses a significant healthcare challenge, accounting for nearly 6.1% of global cancer cases. Early detection, facilitated by population screening utilizing innovative ...biomarkers, is pivotal for mitigating CRC incidence. This study aims to scrutinize the fecal and salivary microbiomes of CRC-positive individuals (CPs) in comparison to CRC-negative counterparts (CNs) to enhance early CRC diagnosis through microbial biomarkers.
A total of 80 oral and stool samples were collected from Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran, encompassing both CPs and CNs undergoing screening. Microbial profiling was conducted using 16S rRNA sequencing assays, employing the Nextera XT Index Kit on an Illumina NovaSeq platform.
Distinct microbial profiles were observed in saliva and stool samples of CPs, diverging significantly from those of CNs at various taxonomic levels, including phylum, family, and species. Saliva samples from CPs exhibited abundance of Calothrix parietina, Granulicatella adiacens, Rothia dentocariosa, and Rothia mucilaginosa, absent in CNs. Additionally, Lachnospiraceae and Prevotellaceae were markedly higher in CPs' feces, while the Fusobacteria phylum was significantly elevated in CPs' saliva. Conversely, the non-pathogenic bacterium Akkermansia muciniphila exhibited a significant decrease in CPs' fecal samples compared to CNs.
Through meticulous selection of saliva and stool microbes based on Mean Decrease GINI values and employing logistic regression for saliva and support vector machine models for stool, we successfully developed a microbiota test with heightened sensitivity and specificity for early CRC detection.
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