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BMJ Case Reports Aug 2019A 62-year-old man was admitted to the emergency department due to fever and acute heart failure. A transthoracic echocardiogram revealed severe aortic valve obstruction....
A 62-year-old man was admitted to the emergency department due to fever and acute heart failure. A transthoracic echocardiogram revealed severe aortic valve obstruction. He was an hepatic transplant recipient and was medicated with everolimus. He underwent mitral and aortic valve replacement with prosthetic valves 4 years ago. Due to his medical background, therapy and clinical presentation, empirical therapy for infective endocarditis was started. Transoesophageal echocardiogram showed severe aortic valve regurgitation but no other findings suggestive of endocarditis. Computed tomography (CT) revealed pulmonary infiltrates compatible with infection and no evidence of septic embolisation. Multiple sets of blood cultures were negative. was isolated in bronchial lavage and antibiotic therapy was adjusted. The patient underwent aortic valve replacement, with no macroscopic findings suggestive of endocarditis. was isolated in the surgically removed valve. Dual antibiotic therapy was successfully administered for 6 weeks.
Topics: Acute Disease; Anti-Bacterial Agents; Aortic Valve Insufficiency; Bronchoalveolar Lavage Fluid; Bronchoscopy; Diagnosis, Differential; Echocardiography, Transesophageal; Endocarditis, Bacterial; Heart Failure; Heart Valve Diseases; Heart Valve Prosthesis; Humans; Lung; Male; Middle Aged; Proteus mirabilis; Tomography, X-Ray Computed; Treatment Outcome
PubMed: 31466989
DOI: 10.1136/bcr-2019-230575 -
Frontiers in Cellular and Infection... 2020is a Gram negative bacterium that is a frequent cause of catheter-associated urinary tract infections (CAUTIs). Its ability to cause such infections is mostly related... (Review)
Review
is a Gram negative bacterium that is a frequent cause of catheter-associated urinary tract infections (CAUTIs). Its ability to cause such infections is mostly related to the formation of biofilms on catheter surfaces. In order to form biofilms, expresses a number of virulence factors. Such factors may include adhesion proteins, quorum sensing molecules, lipopolysaccharides, efflux pumps, and urease enzyme. A unique feature of biofilms that build up on catheter surfaces is their crystalline nature owing to their ureolytic biomineralization. This leads to catheter encrustation and blockage and, in most cases, is accompanied by urine retention and ascending UTIs. Bacteria embedded in crystalline biofilms become highly resistant to conventional antimicrobials as well as the immune system. Being refractory to antimicrobial treatment, alternative approaches for eradicating biofilms have been sought by many studies. The current review focuses on the mechanism by which biofilms are formed, and a state of the art update on preventing biofilm formation and reduction of mature biofilms. These treatment approaches include natural, and synthetic compounds targeting virulence factors and quorum sensing, beside other strategies that include carrier-mediated diffusion of antimicrobials into biofilm matrix. Bacteriophage therapy has also shown successful results for combating biofilms either merely through their lytic effect or by acting as facilitators for antimicrobials diffusion.
Topics: Biofilms; Humans; Proteus mirabilis; Quorum Sensing; Urease; Urinary Tract Infections
PubMed: 32923408
DOI: 10.3389/fcimb.2020.00414 -
MSystems Aug 2023is a Gram-negative bacterium recognized for its unique swarming motility and urease activity. A previous proteomic report on four strains hypothesized that, unlike...
is a Gram-negative bacterium recognized for its unique swarming motility and urease activity. A previous proteomic report on four strains hypothesized that, unlike other Gram-negative bacteria, may not exhibit significant intraspecies variation in gene content. However, there has not been a comprehensive analysis of large numbers of genomes from various sources to support or refute this hypothesis. We performed comparative genomic analysis on 2,060 genomes. We sequenced the genomes of 893 isolates recovered from clinical specimens from three large US academic medical centers, combined with 1,006 genomes from NCBI Assembly and 161 genomes assembled from Illumina reads in the public domain. We used average nucleotide identity (ANI) to delineate species and subspecies, core genome phylogenetic analysis to identify clusters of highly related genomes, and pan-genome annotation to identify genes of interest not present in the model strain HI4320. Within our cohort, is composed of 10 named species and 5 uncharacterized genomospecies. can be subdivided into three subspecies; subspecies 1 represented 96.7% (1,822/1,883) of all genomes. The pan-genome includes 15,399 genes outside of HI4320, and 34.3% (5,282/15,399) of these genes have no putative assigned function. Subspecies 1 is composed of several highly related clonal groups. Prophages and gene clusters encoding putatively extracellular-facing proteins are associated with clonal groups. Uncharacterized genes not present in the model strain HI4320 but with homology to known virulence-associated operons can be identified within the pan-genome. IMPORTANCE Gram-negative bacteria use a variety of extracellular facing factors to interact with eukaryotic hosts. Due to intraspecies genetic variability, these factors may not be present in the model strain for a given organism, potentially providing incomplete understanding of host-microbial interactions. In contrast to previous reports on , but similar to other Gram-negative bacteria, has a mosaic genome with a linkage between phylogenetic position and accessory genome content. encodes a variety of genes that may impact host-microbe dynamics beyond what is represented in the model strain HI4320. The diverse, whole-genome characterized strain bank from this work can be used in conjunction with reverse genetic and infection models to better understand the impact of accessory genome content on bacterial physiology and pathogenesis of infection.
Topics: Humans; Proteus mirabilis; Proteomics; Phylogeny; Virulence; Virulence Factors
PubMed: 37341494
DOI: 10.1128/msystems.00159-23 -
Medicina (Kaunas, Lithuania) Feb 2022: and are related genera of opportunistic pathogens belonging to the family, often a cause of infections in the immunocompromised hosts, such as diabetic patients.... (Observational Study)
Observational Study
: and are related genera of opportunistic pathogens belonging to the family, often a cause of infections in the immunocompromised hosts, such as diabetic patients. Their clinical significance has increased due to their intrinsic resistance to polymyxins, which is often associated with acquired resistance mechanisms. In this study we evaluated the infections caused by and in two groups of patients, with diabetes (group 1) and without diabetes (group 2) admitted to the intensive care unit and surgical wards. The infections were investigated in terms of infection type, risk factors, clinical course, predictive factors for unfavourable outcomes and antibiotic resistance profile. : An observational, retrospective, cross-sectional study was conducted, comprising all patients infected with these pathogens. Bacterial identification and antibiotic sensitivity testing were performed using the Vitek2C automated system. : Comparison of the two groups showed that the statistically significant common infectious risk factors were found less frequently among diabetic patients when compared with non-diabetic patients, and that antimicrobial resistance was significantly lower in the diabetic patient group. However, survival rates did not differ between the two groups, drawing attention to the implications of diabetes as comorbidity. Additionally, with regard to the antibiotic resistance profile, 38.89% of strains isolated from diabetic patients belonged to the difficult-to-treat (DTR) phenotype, contributing to the severity of these infections compared with those caused by , of which 32% were wild type strains and 0% were DTR phenotype. The DTR/extended spectrum beta-lactamase producing isolates more than doubled the risk of mortality, while the presence of nasogastric nutrition tripled the risk. : infections that occurred in diabetic patients proved to be more difficult to treat, the majority of them being healthcare-associated bacteremias.
Topics: Cross-Sectional Studies; Diabetes Mellitus; Enterobacteriaceae Infections; Humans; Proteus Infections; Proteus mirabilis; Providencia; Retrospective Studies
PubMed: 35208593
DOI: 10.3390/medicina58020271 -
Clinical Medicine (London, England) May 2023
Topics: Humans; Urinary Tract Infections; Anti-Bacterial Agents; Syndrome
PubMed: 37236799
DOI: 10.7861/clinmed.2023-0132 -
Journal of the American Association For... May 2022The exclusion of opportunistic pathogens is important for protecting animal health and ensuring desired research outcomes in highly immunodeficient mice. has been...
The exclusion of opportunistic pathogens is important for protecting animal health and ensuring desired research outcomes in highly immunodeficient mice. has been associated with gastrointestinal tract lesions, septicemia, pyelonephritis, splenomegaly, and hepatitis and can influence select mouse models. To inform health-surveillance practices after we experienced difficulty in excluding from our mouse colony, we aimed to determine the likelihood of detecting -positive immunocompromised (SRG), immunovague (), and immunocompetent (CD1) colony mice through culture and PCR testing; to evaluate transmission via 2 sentinel-based approaches (direct contact and indirect dirty-bedding transfer); and to further characterize associated pathology. We hypothesized that immunocompromised mice would be better detectors and transmitters of . Multiple logistic regression models were used for analysis and included PCR copy number, repeated testing, age, sex, and antibiotic-treated (trimethoprim-sulfamethoxazole) diet as covariates. Repeated testing over 10 wk showed that -colonized immunocompromised colony mice were 95 times more likely than immunocompetent mice to test positive by culture and 30 times more likely by PCR assay. Sentinel mice were 15 times more likely to test positive by PCR assay for when exposed by direct contact compared with dirty bedding and 18 times more likely to test positive when exposed to positive immunocompromised as compared with immunocompetent colony mice. After 10 wk of exposure, 3.8% of dirty-bedding sentinel PCR tests were positive, as compared with 30.7% of contact sentinels. Only immunocompromised mice on antibiotic diet (37.5%) developed lesions of the urogenital tract and abdominal cavity consistent with known pathology of . Our findings suggest that PCR testing of dirty-bedding sentinels alone is not sufficient for the detection of in mouse colonies. Direct-contact sentinels and testing of colony mice-especially if immunocompromised-with adjunct culture may facilitate successful bioexclusion.
Topics: Animals; Anti-Bacterial Agents; Bedding and Linens; Housing, Animal; Mice; Proteus mirabilis
PubMed: 35277210
DOI: 10.30802/AALAS-JAALAS-21-000104 -
Antibiotics (Basel, Switzerland) Aug 2023Bioindicator species are used to assess the damage and magnitude of possible impacts of anthropic origin on the environment, such as the reckless consumption of...
Bioindicator species are used to assess the damage and magnitude of possible impacts of anthropic origin on the environment, such as the reckless consumption of antimicrobials. has several characteristics that make it a suitable bioindicator of marine pollution and of the presence of pathogens that cause diseases in humans. This study aimed to investigate the green sea turtle as a reservoir of resistant bacteria, mainly because is the most frequent sea turtle species in Brazilian coastal regions and, consequently, under the intense impact of anthropic factors. Free-living green sea turtles ranging from 42.8 to 92 cm (average = 60.7 cm) were captured from Itaipú Beach, Brazil. Cloaca samples (characterizing the gastrointestinal tract) and neck samples (representing the transient microbiota) were collected. Bacterial species were identified, and their was resistance associated with the antimicrobials cephalothin, ciprofloxacin, gentamicin, tetracycline, and vancomycin. , , and were found resistant to cephalothin and and tetracycline-resistant isolates in cloaca samples. In neck samples, species resistant to tetracycline were sp., , and . This data reinforces that the green turtle is a bioindicator of antimicrobial resistance (AMR).
PubMed: 37627688
DOI: 10.3390/antibiotics12081268 -
Frontiers in Cellular and Infection... 2022The human gut acts as the main reservoir of microbes and a relevant source of life-threatening infections, especially in immunocompromised patients. There, the...
The human gut acts as the main reservoir of microbes and a relevant source of life-threatening infections, especially in immunocompromised patients. There, the opportunistic fungal pathogen adapts to the host environment and additionally interacts with residing bacteria. We investigated fungal-bacterial interactions by coinfecting enterocytes with the yeast and the Gram-negative bacterium resulting in enhanced host cell damage. This synergistic effect was conserved across different isolates and occurred also with non- species and mutants defective in filamentation or candidalysin production. Using bacterial deletion mutants, we identified the hemolysin HpmA to be the key effector for host cell destruction. Spatially separated coinfections demonstrated that synergism between and is induced by contact, but also by soluble factors. Specifically, we identified -mediated glucose consumption and farnesol production as potential triggers for virulence. In summary, our study demonstrates that coinfection of enterocytes with and can result in increased host cell damage which is mediated by bacterial virulence factors as a result of fungal niche modification nutrient consumption and production of soluble factors. This supports the notion that certain fungal-bacterial combinations have the potential to result in enhanced virulence in niches such as the gut and might therefore promote translocation and dissemination.
Topics: Candida; Candida albicans; Coinfection; Enterocytes; Humans; Proteus mirabilis
PubMed: 35651758
DOI: 10.3389/fcimb.2022.866416