Modified gold nanoparticle colorimetric probe-based biosensor for direct and rapid detection of Mycobacterium tuberculosis in sputum specimens.

The incidence of Mycobacterium tuberculosis (MTB) is increasing due to lack of appropriate diagnostic and therapeutic methods. Therefore, early and accurate detection of this bacteria plays a significant role in controlling tuberculosis. This study aimed to design, develop, and implement a direct and rapid detection method of MTB using modified gold nanoparticle (AuNP) colorimetric probe-based biosensor in sputum specimens. Spherical AuNPs were synthesized by the citrate reduction method and were functionalized using thiol-modified oligonucleotides (AuNP-biosensor). AuNP-biosensor and IS6110 PCR were compared to the gold standard in terms of analytical and clinical sensitivity and specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic odds ratio (DOR), and accuracy in 52 clinical specimens. Gold standard was defined as a positive result in concentrated sputum smear microscopy (SSM), culture, or Xpert MTB/RIF.The AuNP-biosensor had 100% sensitivity and specificity for detection of total sputum DNA in less than 15 min with ready-to-use AuNP-biosensor. PPV, NPV, DOR and accuracy of this method were 100%, 100%, 2325 and 100%, respectively. Considering the promising results of the diagnostic value indices of the AuNP-biosensor, the designed method is an affordable, rapid, reliable, and cost-beneficial way for direct detection of MTB in sputum specimens.

Prevalence of Mycobacterium tuberculosis mutations associated with isoniazid and rifampicin resistance: A systematic review and meta-analysis.

Tuberculosis (TB) is still one of the leading causes of worldwide death, especially following the emergence of strains resistant to isoniazid (INH) and rifampicin (RIF). This study aimed to systematically review published articles focusing on the prevalence of INH and/or RIF resistance-associated mutations of Mycobacterium tuberculosis isolates in recent years. Literature databases were searched using appropriate keywords. The data of the included studies were extracted and used for a random-effects model meta-analysis. Of the initial 1442 studies, 29 were finally eligible to be included in the review. The overall resistance to INH and RIF was about 17.2% and 7.3%, respectively. There was no difference between the frequency of INH and RIF resistance using different phenotypic or genotypic methods. The INH and/or RIF resistance was higher in Asia. The S315T mutation in KatG (23.7 %), C-15 T in InhA (10.7 %), and S531L in RpoB (13.5 %) were the most prevalent mutations. Altogether, the results showed that due to S531L in RpoB, S315T in KatG, and C-15 T in InhA mutations INH- and RIF-resistant M. tuberculosis isolates were widely distributed. Thus, it would be diagnostically and epidemiologically beneficial to track these gene mutations among resistant isolates.

High burden of MDR, XDR, PDR, and MBL producing Gram negative bacteria causing infections in Kermanshah health centers during 2019-2020.

Background and Objectives: Microorganisms producing Metallo-Beta-Lactamase (MBL) are a threat and cause of concern as they have become one of the most feared resistance mechanisms. This study was designed to explore the prevalence of MBL production in clinical isolates of Gram negative bacteria using phenotypic MBL detection. Materials and Methods: A total of 248 isolates were collected from various clinical samples and were evaluated for carbapenem resistance and MBL production. All strains were screened for MBL production using Double Disk Confirmatory Test (DDCT). Results: The results of screening for MBL production using phenotypic disk diffusion method showed that in the 85 isolates were carbapenemase positive; including, 10 (16.1%) Klebsiella pneumoniae, 9 (14.5%) Escherichia coli, 58 (93.6%) Acinetobacter baumannii, and 8 (12.9%) Pseudomonas aeruginosa isolates. Also, 83 (97.6) Carbapenemase-producing isolates were resistant to at least four classes of antimicrobials (MDR). Conclusion: A. baumannii was the most common carbapenem resistant bacterium in medical centers in Kermanshah. Significant multiple drug resistance (MDR) incidence was observed compared to different classes of antibiotics.

Global prevalence of Clostridioides difficile in 17,148 food samples from 2009 to 2019: a systematic review and meta-analysis.

BACKGROUND: Clostridioides (Clostridium) difficile is an important infectious pathogen, which causes mild-to-severe gastrointestinal infections by creating resistant spores and producing toxins. Spores contaminated foods might be one of the most significant transmission ways of C. difficile-associated infections. This systematic review and meta-analysis study were conducted to investigate the prevalence of C. difficile in food. METHODS: Articles that published the prevalence of C. difficile in food in PubMed, Web of Science, and Scopus databases were retrieved using selected keywords between January 2009 and December 2019. Finally, 17,148 food samples from 60 studies from 20 countries were evaluated. RESULTS: The overall prevalence of C. difficile in various foods was 6.3%. The highest and lowest levels of C. difficile contamination were detected to seafood (10.3%) and side dishes (0.8%), respectively. The prevalence of C. difficile was 4% in cooked food, 6.2% in cooked chicken and 10% in cooked seafood. CONCLUSIONS: There is still little known concerning the food-borne impact of C. difficile, but the reported contamination might pose a public health risk. Therefore, to improve the food safety and prevent contamination with C. difficile spores, it is necessary to observe hygienic issues during foods preparation, cooking and transfer.

Prevalence of Clostridioides difficile contamination in the healthcare environment and instruments: A systematic review and meta-analysis.

Introduction: Worldwide, Clostridioides difficile infection is becoming one of the most common healthcare-associated infections. Management and control of this infection in healthcare facilities are associated with screening for environmental and instrumental C. difficile contamination. This systematic review and meta-analysis aimed to assess the overall prevalence of C. difficile in hospital settings, medical devices, and instruments. Methods: Four main databases, PubMed, Web of Science, Google Scholar, and Scopus, were searched using the keywords Clostridioides difficile, Clostridium difficile, C. difficile, clostridia, Clostridium spp., hospital environments, antibiotic associate colitis, intensive care unit, and ward in combination as a search strategy. The PRISMA checklist was used for selecting eligible studies. Results: A total of 11 eligible articles published between 2012 and 2021 were included. The overall pooled prevalence of C. difficile in hospital environments was 14.9%. The highest and lowest prevalence were reported for India (51.1%) and the USA (1.6%), respectively. The highest prevalence was reported for beds (46.3%). A significant heterogeneity was seen between C. difficile prevalence in hospital environments in different samples. The highest and lowest prevalence was reported for floor corners (63.2%) and privacy curtains (1.4%), respectively. Conclusions: In conclusion, hospitals' medical devices and environmental surfaces are considered a crucial source of Clostridioides difficile infection. In this regard, we strongly recommend revising and improving the cleaning and disinfection methods in hospitals and quality control of cleaning adequacy.

A worldwide systematic review and meta-analysis of bacteria related to antibiotic-associated diarrhea in hospitalized patients.

INTRODUCTION: Antibiotic-associated diarrhea (AAD) is a major hospital problem and a common adverse effect of antibiotic treatment. The aim of this study was to investigate the prevalence of the most important bacteria that cause AAD in hospitalized patients. MATERIALS AND METHODS: PubMed, Web of Science and Scopus databases were searched using multiple relevant keywords and screening carried out based on inclusion/exclusion criteria from March 2001 to October 2021. The random-effects model was used to conduct the meta-analysis. RESULTS: Of the 7,377 identified articles, 56 met the inclusion criteria. Pooling all studies, the prevalence of Clostridioides (Clostridium) difficile, Clostridium perfringens, Klebsiella oxytoca, and Staphylococcus aureus as AAD-related bacteria among hospitalized patients were 19.6%, 14.9%, 27%, and 5.2%, respectively. The prevalence of all four bacteria was higher in Europe compared to other continents. The highest resistance of C. difficile was estimated to ciprofloxacin and the lowest resistances were reported to chloramphenicol, vancomycin, and metronidazole. There was no or little data on antibiotic resistance of other bacteria. CONCLUSIONS: The results of this study emphasize the need for a surveillance program, as well as timely public and hospital health measures in order to control and treat AAD infections.