- Volume 71, Issue 4, 2022
Volume 71, Issue 4, 2022
- Reviews
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Microbial–stem cell interactions in periodontal disease
More LessPeriodontitis is initiated by hyper-inflammatory responses in the periodontal tissues that generate dysbiotic ecological changes within the microbial communities. As a result, supportive tissues of the tooth are damaged and periodontal attachment is lost. Gingival recession, formation of periodontal pockets with the presence of bleeding, and often suppuration and/or tooth mobility are evident upon clinical examination. These changes may ultimately lead to tooth loss. Mesenchymal stem cells (MSCs) are implicated in controlling periodontal disease progression and have been shown to play a key role in periodontal tissue homeostasis and regeneration. Evidence shows that MSCs interact with subgingival microorganisms and their by-products and modulate the activity of immune cells by either paracrine mechanisms or direct cell-to-cell contact. The aim of this review is to reveal the interactions that take place between microbes and in particular periodontal pathogens and MSCs in order to understand the factors and mechanisms that modulate the regenerative capacity of periodontal tissues and the ability of the host to defend against putative pathogens. The clinical implications of these interactions in terms of anti-inflammatory and paracrine responses of MSCs, anti-microbial properties and alterations in function including their regenerative potential are critically discussed based on literature findings. In addition, future directions to design periodontal research models and study ex vivo the microbial–stem cell interactions are introduced.
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- Antimicrobial Resistance
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Activity of ceftolozane/tazobactam against Gram-negative isolates among different infections in Hong Kong: SMART 2017–2019
Introduction. Ceftolozane/tazobactam was approved by the Drug Office, Department of Health, Government of the Hong Kong Special Administrative Region in 2017.
Hypothesis/Gap Statement. Currently the in vitro activity of ceftolozane/tazobactam against Gram-negative pathogens isolated from patients in Hong Kong is undocumented. It would be prudent to document the activity of ceftolozane/tazobactam against Pseudomonas aeruginosa and Enterobacterales isolated from hospitalized patients in Hong Kong.
Aim. To describe the in vitro susceptibility of recent clinical isolates of P. aeruginosa and the two most common Enterobacterales species ( Klebsiella pneumoniae , Escherichia coli ) cultured from respiratory tract, intra-abdominal, urinary tract and bloodstream infection samples to ceftolozane/tazobactam and other commonly used antimicrobial agents.
Methodology. CLSI-defined broth microdilution MICs were determined and interpreted for Gram-negative isolates collected in Hong Kong from 2017 to 2019 by the SMART surveillance programme.
Results. For P. aeruginosa , 96.7 % of isolates (n=210) were susceptible to ceftolozane/tazobactam, while susceptibility rates were ≥14 % lower to meropenem (82.9 % susceptible), cefepime (82.4 %), ceftazidime (81.4 %), piperacillin/tazobactam (76.7 %) and levofloxacin (79.5 %). Ceftolozane/tazobactam inhibited 85.7 % of piperacillin/tazobactam-nonsusceptible isolates, 80.6–82.1 % of cefepime-, ceftazidime- or meropenem-nonsusceptible isolates, and 75.9 % of multidrug-resistant (MDR) isolates of P. aeruginosa . For K. pneumoniae , 96.1 % of isolates (n=308) were susceptible to ceftolozane/tazobactam compared with meropenem (99.0 % susceptible), piperacillin/tazobactam (93.8 %), cefepime (85.7 %) and ceftazidime (85.4 %). The majority (88.3 %) of ESBL (extended-spectrum β-lactamase) non-CRE (carbapenem-resistant Enterobacterales) phenotype isolates of K. pneumoniae were susceptible to ceftolozane/tazobactam, comparable to piperacillin/tazobactam (85.0 %) but lower than meropenem (100 %). For E. coli , 98.5 % of isolates (n=609) were susceptible to ceftolozane/tazobactam compared to meropenem (99.3 % susceptible), piperacillin/tazobactam (96.7 %), ceftazidime (82.3 %) and cefepime (76.5 %). The majority (96.7 %) of ESBL non-CRE phenotype isolates of E. coli were susceptible to ceftolozane/tazobactam, similar to both meropenem (100 %) and piperacillin/tazobactam (94.5 %).
Conclusions. Overall, >96 % of clinical isolates of P. aeruginosa , K. pneumoniae and E. coli collected in Hong Kong in 2017–2019 were susceptible to ceftolozane/tazobactam, while the activity of several commonly prescribed β-lactams was reduced, especially for P. aeruginosa . Continued surveillance of ceftolozane/tazobactam and other agents is warranted.
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Evaluation of in vitro activity of fosfomycin, and synergy in combination, in Gram-negative bloodstream infection isolates in a UK teaching hospital
Introduction. Fosfomycin has retained activity against many multi-drug resistant (MDR) Gram-negatives, and may be useful against extended spectrum beta-lactamase (ESBL) producing and carbapenem-resistant Enterobacterales to improve clinical outcomes.
Hypothesis/Gap Statement. There are few data from the UK on the susceptibility of invasive Gram-negative isolates to fosfomycin, especially in the era of increasing use of oral fosfomycin for urinary tract infections (UTIs).
Aim. We evaluated fosfomycin susceptibility against 100 consecutive Gram-negative bloodstream isolates, both individually, and in combination with other mechanistically similar and differing antibiotics. The aim was to investigate the synergy between antibiotic combinations against several E. coli, K. pneumoniae and P. aeruginosa isolates with variable levels of resistance.
Methodology. Disc diffusion and MIC test strip methods applying revised EUCAST guidelines for Fosfomycin were used, followed by the MTS™ ‘cross synergy’ method for ‘resistant’ isolates as defined below: (a) Fosfomycin resistant by MIC test strip; (b) MDR isolates defined as being resistant to ≥3 classes of antibiotics (based on routine sensitivity testing; beta lactams were considered as a single class), and/or (c) AMP C or ESBL or carbapenemase producers (or carbapenem resistant). FIC Index (Fractional Inhibitory Concentration Index) calculations were used to interpret findings, whereby: FIC = (MICA combination A+B/ MIC agent A) + (MICB combination A+B/ MIC agent B). A result of ≤0.5 was taken to indicate ‘synergy’, >0.5 and ≤1.0 to indicate ‘additive’ effect, >1.0 and ≤4.0 to indicate ‘indifference’, and >4.0 to indicate ‘antagonism’.
Results. We found that 95/100 isolates were susceptible to fosfomycin by MIC test strip, with 88/100 isolates susceptible to fosfomycin by disc, based on EUCAST guideline breakpoints. A total of 30/100 isolates (the more ‘resistant’ of the 100) were eligible for synergy testing according to our definitions (see Methodology), with the remaining 70 isolates not tested further. Seventeen out of 30 were MDR, 2/30 were AMP C producers and 9/30 were ESBL producers. Overall, 34/300 (11 %) of all combination tests showed synergy and 161/300 (54 %) were additive. Synergy was most commonly detected between fosfomycin and beta-lactam antibiotics, including piperacillin/tazobactam (10/30; 33 %), ceftazidime/avibactam (10/30; 30 %), and temocillin (8/30; 27 %). An additive effect was most commonly detected with aztreonam (25/30; 83 %) and meropenem (25/30; 83 %), but 100 % indifference was found with tigecycline (30/30). No antagonism was identified with any antibiotic combination.
Conclusion. Fosfomycin non-susceptibility by MIC test strip was unusual. Synergy was variable when combining fosfomycin with other antibiotics against the more ‘resistant’ isolates. Synergistic/additive effects were detected for beta-lactam/fosfomycin combinations in >80 % of all such combinations, suggesting beta-lactams may be the preferred partner for fosfomycin. Agents with a discordant site of action were more likely to result in indifference. Antagonism was not detected.
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- Clinical Microbiology
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Metagenomics analysis of cultured mucosal bacteria from colorectal cancer and adjacent normal mucosal tissues
Introduction. Colorectal cancer (CRC) is one of the most common cancers worldwide. Multiple risk factors are involved in CRC development, including age, genetics, lifestyle, diet and environment. Of these, the role of the gut microbiota in cancer biology is increasingly recognized.
Hypothesis/Gap Statement. Micro-organisms have been widely detected in stool samples, but few mucosal samples have been detected and sequenced in depth.
Aim. Analysis of cultured mucosal bacteria from colorectal cancer and adjacent normal mucosal tissues with metagenomics sequencing.
Methodology. Twenty-eight paired tumour and non-tumour tissues from 14 patients undergoing surgery for CRC were analysed. We removed the influence of eukaryotic cells via culture. The composition of mucosal microbiota in intestinal mucosa were detected and analysed with metagenomic sequencing.
Results. Compared with non-cultured mucosal sample, 80 % bacteria species could be detected after culture. Moreover, after culture, additional 30 % bacteria could be detected, compared with non-cultured samples. Since after culture it was difficult to estimate the original abundance of microbiome, we focused on the identification of the CRC tissue-specific species. There were 298 bacterial species, which could only be cultured and detected in CRC tissues. Myroides odoratimimus and Cellulophaga baltica could be isolated from all the tumour samples of 14 CRC patients, suggesting that these species may be related to tumour occurrence and development. Further functional analysis indicated that bacteria from CRC tissues showed more active functions, including basic metabolism, signal transduction and survival activities.
Conclusion. We used a new method based on culture to implement information on prokaryotic taxa, and related functions, which samples were from colorectal tissues. This method is suitable for removing eukaryotic contamination and detecting micro-organisms from other tissues.
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Symptoms and PCR testing interval for bacterial pathogens in patients with diarrhoea
More LessIntroduction . Acute diarrhoea can be caused by Salmonella species, Shigella species, Yersinia enterocolitica , Campylobacter species and Plesiomonas shigelloides (SSYCP). In clinical practice, however, polymerase chain reaction (PCR) for SSYCP is frequently performed as part of the diagnostic work-up for patients with chronic diarrhoea and gastrointestinal complaints.
Hypothesis. This study postulates that PCR for SSYCP is of limited clinical use in patients with chronic diarrhoea and gastrointestinal complaints.
Aim. The primary aim of this study is to evaluate whether testing for SSYCP remains sensible in patients with chronic diarrhoea and gastrointestinal symptoms and if earlier testing leads to more positive PCR results.
Methodology. Between January 2017 and December 2018, data on PCR results, culture results, symptoms, symptom to testing interval (STI) and immune status were retrospectively collected from the medical records of patients with gastrointestinal symptoms for whom PCR results for SSYCP were available. The STIs of PCR-positive patients and PCR-negative patients were compared.
Results. In total, 146 PCR-positive and 149 PCR-negative patients were included. STIs of <7 days occurred in 55 % of all PCR-positive patients compared to 38 % in PCR-negative patients. PCR-positive patients were more often tested within 7 days after onset of gastrointestinal symptoms or diarrhoea. A third of PCR-positive patients had an STI of >7 days. Immunocompromised patients had a shorter STI. Admitted patients had a shorter STI. Eighty-six PCR-positive patients had a positive culture (58 %). Antibiotic use 3 months prior to PCR testing was correlated with negative PCR results.
Conclusions . This study shows that early testing correlates with more positive PCR results and underlines that PCR for SSYCP is of lesser importance in the diagnostic workup of chronic diarrhoea and/or gastrointestinal symptoms. The shorter STI found in immunocompromised patients is possibly due to a lower threshold for testing in this population. It is also important to take recent antibiotic use into consideration when interpreting PCR results, given the correlation between negative PCR results and antibiotic use. Careful and precise documentation of symptoms in medical records is essential for clinical practice and research.
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- Disease, Diagnosis and Diagnostics
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The dark art of syphilis serology - an analysis of testing algorithms at a UK reference laboratory
Introduction. Due to the complex nature of treponemal serology interpretation, testing algorithms vary across the UK.
Gap statement. There is currently no gold standard method for interpretation of discordant serology results.
Aim. To analyse serological response in early infection and to determine the best approach for discordant total antibody EIA and TPPA samples.
Methodology. National reference laboratory serology and PCR (genital ulcer swabs) results from 2010 to 2017 were extracted from an electronic laboratory database.
Results. A total of 24149 sera underwent analysis. Of syphilis PCR positive cases with contemporaneous sera, 33% (17/52) were IgM positive/equivocal, whilst all were EIA and TPPA positive. No sera with isolated IgM positivity (0/90) demonstrated seroconversion consistent with early treponemal infection, in contrast to 17% (2/12) of sera with isolated TPPA positivity. Isolated EIA positivity was observed in 6.2% (1499/24149) samples with the same result on repeat testing in 73% (154/211). In 100 samples with discordant EIA/TPPA results, IgG Immunoblot was more commonly positive (12/41, 29%) or equivocal (24/41, 59%), in those with a higher EIA antibody index, compared to those with a low antibody index, of which none tested positive and 2/3 (67 %) were equivocal.
Conclusion. Isolated IgM positivity was not helpful in identifying early infection; isolated total antibody EIA positivity is unlikely to be a significant finding. IgG immunoblot testing was unable to determine clear treponemal antibody status in nearly half of all EIA/TPPA discordant samples.
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Effect of RNA quality to SARS-CoV-2 RT-qPCR detection from saliva
Saliva is an alternative sample material to nasopharyngeal swab in SARS-CoV-2 diagnostics. We investigated possible aspects to improve the reliability of SARS-CoV-2 detection from saliva. Saliva was collected from asymptomatic healthy subjects (n=133) and COVID-19 patients (n=9). SARS-CoV-2 detection was performed with quantitative reverse-transcriptase PCR (RT-qPCR) with two viral and one host target serving as an internal control. The use of internal control revealed that in the first RT-qPCR run 25–30 % of assays failed. The failure is associated with poor RNA quality. When the amount of RNA was cut down to half from the original amount, the performance of RT-qPCR was greatly enhanced (95 % of the assays succeeded). The quality of RNA was not affected by the use of different nucleic acid stabilizing buffers. Our study showed that saliva is suitable material for RT-qPCR based SARS-CoV-2 diagnostics, but the use of internal control is essential to distinguish the true negative samples from failed assays.
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Development of an ELISA to distinguish between foot-and-mouth disease virus infected and vaccinated animals utilising the viral non-structural protein 3ABC
Introduction. Foot-and-mouth disease (FMD) is a highly contagious and economically devastating viral disease of livestock and is endemic in much of Asia, including Pakistan. Vaccination is used to control disease outbreaks and sensitive diagnostic methods which can differentiate infected animals from vaccinated animals (DIVA) are essential for monitoring the effectiveness of disease control programmes. Tests based on the detection of the non-structural protein (NSP) 3ABC are reliable indicators of virus replication in infected and vaccinated populations.
Hypothesis/Gap statement. Diagnosis of FMD is expensive using commercial ELISA kits, yet is essential for controlling this economically-important disease.
Aim. The development of a low-cost diagnostic ELISA, using protein made in Escherichia coli .
Methodology. In this study, the viral precursor protein 3ABC (r3ABC) was expressed in E. coli , solubilised using detergent and purified using nickel affinity chromatography. The fusion protein contained an attenuating mutation in the protease and a SUMO tag. It was characterised by immunoblotting and immunoprecipitation, which revealed antigenicity against virus-specific polyclonal sera. Using r3ABC, an indirect ELISA was developed and evaluated using field sera from healthy/naïve, vaccinated and infected animals.
Results. The diagnostic sensitivity and specificity of the r3ABC in-house ELISA were 95.3 and 96.3% respectively. The ELISA was validated through comparison with the commercially available ID Screen FMD NSP competition kit. Results indicated good concordance rates on tested samples and high agreement between the two tests.
Conclusion. The ELISA described here can effectively differentiate between infected and vaccinated animals and represents an important low cost tool for sero-surveillance and control of FMD in endemic settings.
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An isothermal amplification-coupled dipstick for the rapid detection of COVID-19
More LessEarly detection of coronavirus disease 2019 (COVID-19) is critical for both initiating appropriate treatment and preventing the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent. A simple and rapid diagnostic test that can be performed without any expensive equipment would be valuable for clinicians working in a low-resource setting. Here, we report a point-of-care detection technique for COVID-19 that combines the power of isothermal amplification (reverse transcription helicase-dependent amplification, RT-HDA) and dipstick technologies. The limit of detection of this diagnostic test is six copies of SARS-CoV-2 µl−1 in clinical specimens. Of the 22 clinical specimens tested, RT-HDA-coupled dipstick correctly identified all positive and negative specimens. The RT-HDA can be performed over a heating block and the results can be interpreted visually with the dipstick technology without any specialized equipment. Furthermore, the RT-HDA-coupled dipstick could be performed in a short turnaround time of ~2 h. Thus, the RT-HDA-coupled dipstick could serve as a point-of-care diagnostic test for COVID-19 in a low-resource environment.
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Speed and safety of mass spectrometry for identification of Burkholderia pseudomallei directly from spiked blood cultures
More LessBurkholderia pseudomallei is a bipolar Gram-negative bacillus and the causative agent of melioidosis; an infectious disease which commonly presents with bacteraemia.
Data regarding direct from blood culture identification of B. pseudomallei using the Vitek mass spectrometer (MS) are limited.
The authors aim to assess the safety and sensitivity of the Vitek MS for identification of B. pseudomallei from spiked positive blood culture samples.
Safety was assessed by determining the ability of the standard MS α-cyano-4-hydroxycinnamic acid (CHCA) matrix solution to inactivate B. pseudomallei . Organism identification using the manufacturer’s blood culture extraction method was compared to an in-house technique. Additionally, identification following abbreviated agar incubation of blood culture broth was performed.
All 70 MS target spots were inactivated by the matrix solution. The manufacturer’s blood culture extraction method identified 0/26 (0%) B. pseudomallei samples. An in-house method using the spun deposit from blood culture broth samples identified 38/38 (100%) B. pseudomallei samples. MS analysis of a blood culture broth drop on Chocolate agar following a 6 h incubation identified 30/32 (94%) samples.
Decreased time to diagnosis of melioidosis bacteraemia is likely to improve patient outcomes. This study adds to the literature with regards to the utility of MALDI-TOF MS identification of B. pseudomallei both directly from positive blood culture broth and a subsequent 6 h plate incubation. The use of a standard matrix solution inactivates the organism, and use of the spun deposit from a positive blood culture broth is most effective for early identification of B. pseudomallei .
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- Medical Mycology
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Molecular identification and antifungal susceptibility of clinically relevant and cryptic species of Aspergillus sections Flavi and Nigri
Introduction. Aspergillus sections Flavi and Nigri comprise clinically relevant and cryptic species that differ significantly in drug susceptibility, meaning that effective treatment depends on correct species identification.
Hypothesis/Gap Statement. There are no comprehensive data for molecular identification and antifungal susceptibility testing (AFST) of clinically relevant and cryptic species of Aspergillus sections Flavi and Nigri as the main agents of invasive and non-invasive aspergillosis in Iran.
We aimed to perform molecular identification and AFST of 213 clinical Aspergillus isolates belonging to sections Flavi and Nigri.
Molecular identification of isolates was performed using sequencing of the β-tubulin gene and in vitro AFST was conducted according to the Clinical and Laboratory Standards Institute (CLSI) M38-A3 guidelines.
Results. The most common isolates in sections Flavi and Nigri were Aspergillus flavus (110/113, 97.3 %) and Aspergillus tubingensis (49/100, 49.0 %), respectively. A total of 62/213 (29.1 %) isolates belonging to cryptic species were identified; among them, A. tubingensis was the most prevalent (49/62, 79.0%). Aspergillus flavus and A. niger isolates that responded to the minimum inhibitory concentrations (MICs) of itraconazole above the epidemiological cutoff values were the most frequently detected: 8/110 (7.3 %) and 3/41 (7.3 %), respectively. In section Flavi, Aspergillus alliaceus responded to amphotericin B at a high MIC (>16 µg mL−1) and in section Nigri, one of the three Aspergillus luchuensis/awamori isolates responded to itraconazole at an MIC >16 µg ml−1. Interestingly, for all Aspergillus welwitschiae isolates, the MIC50 and MIC90 of itraconazole were both 16 µg ml−1.
Conclusion. A considerable presence of A. flavus and A. niger isolates showing non-wild-type responses to azoles in clinical cases of aspergillosis indicates the importance of classifying clinical Aspergillus isolates at the species level and performing antifungal susceptibility testing on the isolates, which would ensure appropriate treatment.
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- Microbiome and Microbial Ecology in Health
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Longitudinal analysis of the impact of oral contraceptive use on the gut microbiome
Introduction. Evidence has linked exogenous and endogenous sex hormones with the human microbiome.
Hypothesis/Gap statement. The longitudinal effects of oral contraceptives (OC) on the human gut microbiome have not previously been studied.
Aim. We sought to examine the longitudinal impact of OC use on the taxonomic composition and metabolic functions of the gut microbiota and endogenous sex steroid hormones after initiation of OC use.
Methodology. We recruited ten healthy women who provided blood and stool samples prior to OC use, 1 month and 6 months after starting OC. We measured serum levels of sex hormones, including estradiol, progesterone, sex hormone-binding globulin (SHBG), and total testosterone. Shotgun metagenomic sequencing was performed on DNA extracted from faecal samples. Species and metabolic pathway abundances were determined using MetaPhlAn2 and HUMAnN2. Multivariate association with linear models was used to identify microbial species and metabolic pathways associated with OC use and endogenous levels of sex hormones.
Results. The percentage variance of the microbial community explained by individual factors ranged from 9.9 % for age to 2.7 % for time since initiation of OC use. We observed no changes in the diversity or composition of the gut microbiome following OC initiation. However, the relative abundance of the biosynthesis pathways of peptidoglycan, amino acids (lysine, threonine, methionine, and tryptophan), and the NAD salvage pathway increased after OC initiation. In addition, serum levels of estradiol and SHBG were positively associated with Eubacterium ramulus, a flavonoid-degrading bacterium. Similarly, microbes involving biosynthesis of l-lysine, l-threonine, and l-methionine were significantly associated with lower estradiol, SHBG, and higher levels of total testosterone.
Conclusion. Our study provides the first piece of evidence supporting the association between exogenous and endogenous sex hormones and gut microbiome composition and function.
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- Molecular and Microbial Epidemiology
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Clonal spread of ArmA- and OXA-23-coproducing Acinetobacter baumannii International Clone 2 in Brazil during the first wave of the COVID-19 pandemic
Introduction. Carbapenem-resistant Acinetobacter baumannii (CRAB) is the primary pathogen causing hospital-acquired infections. The spread of CRAB is mainly driven by the dissemination of resistant clones, and in Latin America, International Clones IC-1 (also known as clonal complex CC1), IC-4 (CC15) and IC-5 (CC79) are the most prevalent.
Gap Statement. There are no documented outbreaks of CRAB International Clone 2 (IC-2) reported in Brazil.
Aim. To describe a large outbreak of CRAB caused by the uncommon IC-2 in a Brazilian COVID-19 hospital.
Methodology. From May 2020 to May 2021, 224 patients infected or colonized with CRAB were identified in a single hospital; 92 % of them were also infected with SARS-CoV-2. From these patients, 137 isolates were recovered and subjected to antimicrobial susceptibility testing, PCR analysis and molecular typing. Whole-genome sequencing and downstream analysis were carried out on a representative isolate (the first available isolate).
Results. In 76 % of the patients, a single OXA-23-producing CRAB IC-2 was identified. All the isolates were susceptible to polymyxin B, but highly resistant (>95 %) to aminoglycosides, fluoroquinolones and beta-lactams. Genomic analysis revealed that the representative isolate also carried the 16S rRNA Methylase ArmA, which was detected for the first time in this species in Brazil.
Conclusion. We report the rapid spread of an emerging CRAB clone responsible for causing a large outbreak in a hospital in Brazil, a country with predominance of other CRAB clones. Continuous and prospective surveillance is warranted to evaluate the impact of this clone in Brazilian hospital settings.
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- Pathogenesis, Virulence and Host Response
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Evaluation of antioxidant status and oxidative stress markers in HTLV-1 infected individuals: correlation with the severity of virus-induced complications
More LessIntroduction. Human T-cell lymphotropic virus type 1 (HTLV-1), a well-known member of the retroviridae family, potentially causes serious outcomes including adult T-cell leukaemia/lymphoma (ATLL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM-TSP). Oxidative stress plays a key role in progression and clinical exacerbation of several chronic infections. We have previously shown a reduction in serum total antioxidant capacity (TAC) during HTLV-1 infection and this study was set out to investigate the reasons for TAC reduction.
Hypothesis/Gap Statement. Oxidant/antioxidant imbalance during HTLV-1 infection may result from disruptions in oxidant levels or antioxidant defence system.
Aim. This study aimed to analyse the key enzymes and oxidant molecules playing important roles in virus-induced oxidative stress.
Methodology. We measured serum activities of the major antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) as well as serum concentrations of the main oxidant markers: nitric oxide (NO) and malondialdehyde (MDA). Totally 40 HTLV-1 infected patients and 40 healthy controls were enrolled in this study. The patient group consisted of chronic carriers and patients with HAM-TSP (N=20).
Results. The current study found that serum levels of MDA and NO were significantly higher in patient groups particularly in HAM-TSP patients (P<0.05). In addition, a reductive trend was observed in the serum activities of CAT, SOD, and GPX in HTLV-1 infected patients compared with healthy controls (P<0.05).
Conclusion. Reduced activities of CAT, SOD, and GPX antioxidant enzymes along with the observed elevated concentrations of oxidant molecules may contribute to oxidative stress and worse outcomes during HTLV-1 infection.
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Anti-inflammatory effects of curcumin-loaded niosomes on respiratory syncytial virus infection in a mice model
Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in paediatrics. While antivirals are apparent candidates to treat RSV-induced diseases, they have not yet met expectations and have remained in infancy. There is growing evidence to suggest that modulating the exacerbated inflammation during RSV infection can improve disease outcome.
Curcumin-loaded niosomes have anti-inflammatory effects against RSV-induced respiratory disease by reducing immune cells' infiltration and inflammatory cytokines' production.
This study evaluated the effects of curcumin-loaded niosomes on RSV-induced immunopathology in a mice model.
Curcumin-loaded niosomes were prepared using the thin-film hydration method and characterized in vitro. Female Balb/c mice were infected by RSV-A2 and treated daily with curcumin-loaded niosomes. The potential anti-inflammatory effects of curcumin-loaded niosomes were evaluated on day 5 after infection.
Using curcumin-loaded niosomes decreased immune cell influx and the inflammatory mediators (MIP-1α, TNF-α and IFN-γ) production in the lung, resulting in alleviated lung pathology following RSV infection.
These findings indicate that curcumin-loaded niosomes have anti-inflammatory potential and could be a promising candidate to alleviate RSV-associated immunopathology.
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Uropathogenic Escherichia coli can cause cystitis at extremely low inocula in a pig model
More LessUrinary tract infection (UTI) is one of the most common bacterial infections worldwide. Experimental models that accurately reflect the high susceptibility to UTI in humans have, however, been lacking. This situation has limited detailed research into the early bladder colonization by uropathogens and the early innate defence mechanisms elicited to prevent this. We recently presented a model of urinary tract infection in pigs, animals that are naturally susceptible to UTI and have greater similarity to the physiology and anatomy of the human urinary tract than traditional rodent UTI models. In the current study, we used the pig model to investigate the minimal infectious inoculum of uropathogenic Escherichia coli , the most common cause of urinary tract infection. We show that in this animal a few individual bacteria that come into contact with the urothelium can give rise to fulminant cystitis, indicating the high infectious potential of uropathogenic E. coli .
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- Prevention, Therapy and Therapeutics
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Prebiotics and probiotics for autism spectrum disorder: a systematic review and meta-analysis of controlled clinical trials
More LessIntroduction. Autism spectrum disorder (ASD) is a neurodevelopmental disorder. The discovery of the influence of gut microbiota on mental illness opens up new research avenues for the role of gut microbiota modifiers, such as probiotics or prebiotics, as a potential course of treatment. Potential treatments have received considerable attention in recent years.
Aim. The meta-analysis only included clinical controlled trials to explore whether probiotics and prebiotics can improve the overall severity of ASD symptoms in children, the severity of gastrointestinal (GI) problems and the comorbid psychopathlology in ASD.
Gap statement. Although systematic reviews have been conducted in this area in the past, most of them are mixed experimental designs, and the reliability of the conclusions remains to be determined. To the best of our knowledge, no systematic review of randomized controlled trials (RCTs) has been conducted.
Methodology. A meta analysis used a combination of subject terms and free words, or used keywords, titles, and abstracts to conduct in PubMed, Web of Science, Embase, and Cochrane Library to identify studies relevant to the current review.
Result. The results of the meta-analysis showed that probiotics and prebiotics did not significantly improve the severity of ASD patients, GI problems and comorbid psychopathlology in ASD, and the result is contradictory to the previous literatures.
Conclusion. Since there are relatively few clinical controlled trials that can be included, the results of this study still need to be further verified in the clinic. In the future, more randomized controlled studies, more research populations, and the use of more professional clinicians may provide more robust research results.
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Calcium phosphate adjuvanted nanoparticles of outer membrane proteins of Salmonella Typhi as a candidate for vaccine development against Typhoid fever
Introduction. The conventional adjuvants used in vaccines have limitations like induction of an imbalanced Th1 and Th2 immune response. To overcome this limitation, novel adjuvants and newer forms of existing adjuvants like calcium phosphate nanoparticles are being tested.
Hypothesis/Gap Statement. Calcium phosphate adjuvanted outer membrane proteins vaccine may work as an efficient, safe and cost effective vaccine against Salmonella Typhi.
Aim. Our goals were to evaluate the potential of calcium phosphate nanoparticles as an adjuvant using outer membrane proteins (Omps) of Salmonella Typhi as antigens for immune response, with montanide (commercially available adjuvant) as control, and its toxicity in rats.
Methodology. Calcium phosphate adjuvanted outer membrane proteins nanoparticles were synthesized and characterized. The efficacy of vaccine formulation in mice and toxicity assay were carried out in rats.
Results. The calcium phosphate nanoparticles varying in size between 20–50 nm had entrapment efficiency of 41.5% and loading capacity of 54%. The calcium phosphate nanoparticle-Omps vaccine formulation (nanoparticle-Omps) induced a strong humoral immune response, which was significantly higher than the control group for the entire period of study. In the montanide-Omps group the initial very high immune response declined steeply and then remained steady. The immune response induced by nanoparticle-Omps did not change appreciably. The cell mediated immune response as measured by lymphocyte proliferation assay and delayed type hypersensitivity test showed a higher response (P<0.01) for the nanoparticles-Omps group as compared to montanide-Omps group. The bacterial clearance assay also showed higher clearance in the nanoparticles-Omps group as compared to montanide-Omps group (approx 1.4%). The toxicity analysis in rats showed no difference in the values of toxicity biomarkers and blood chemistry parameters, revealing vaccine formulation was non-toxic in rats.
Conclusion. Calcium phosphate nanoparticles as adjuvant in vaccines is safe, have good encapsulation and loading capacity and induce a strong cell mediated, humoral and protective immune response.
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Volumes and issues
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Volume 73 (2024)
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Volume 72 (2023 - 2024)
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Volume 71 (2022)
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Volume 70 (2021)
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Volume 69 (2020)
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Volume 68 (2019)
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Volume 67 (2018)
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Volume 66 (2017)
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Volume 65 (2016)
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Volume 64 (2015)
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Volume 63 (2014)
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Volume 62 (2013)
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Volume 61 (2012)
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Volume 60 (2011)
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Volume 59 (2010)
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Volume 58 (2009)
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Volume 57 (2008)
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Volume 56 (2007)
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Volume 55 (2006)
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Volume 54 (2005)
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Volume 53 (2004)
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Volume 52 (2003)
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Volume 51 (2002)
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Volume 50 (2001)
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Volume 49 (2000)
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Volume 48 (1999)
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Volume 47 (1998)
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Volume 46 (1997)
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Volume 45 (1996)
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Volume 44 (1996)
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Volume 43 (1995)
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Volume 42 (1995)
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Volume 41 (1994)
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Volume 40 (1994)
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Volume 39 (1993)
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Volume 38 (1993)
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Volume 37 (1992)
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Volume 36 (1992)
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Volume 35 (1991)
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Volume 34 (1991)
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Volume 33 (1990)
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Volume 32 (1990)
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Volume 31 (1990)
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Volume 30 (1989)
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Volume 29 (1989)
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Volume 28 (1989)
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Volume 27 (1988)
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Volume 26 (1988)
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Volume 25 (1988)
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Volume 24 (1987)
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Volume 23 (1987)
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Volume 22 (1986)
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Volume 21 (1986)
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Volume 20 (1985)
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Volume 19 (1985)
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Volume 18 (1984)
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Volume 17 (1984)
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Volume 16 (1983)
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Volume 15 (1982)
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Volume 14 (1981)
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Volume 13 (1980)
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Volume 12 (1979)
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Volume 11 (1978)
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Volume 10 (1977)
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Volume 9 (1976)
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Volume 8 (1975)
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Volume 7 (1974)
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Volume 6 (1973)
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Volume 5 (1972)
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Volume 4 (1971)
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Volume 3 (1970)
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Volume 2 (1969)
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Volume 1 (1968)