Misidentification of Streptococcus uberis as a Human Pathogen: A Case Report and Literature Review

Domenico, Enea Gino Di; Toma, Luigi; Prignano, G.; Pelagalli, Lorella; Cavallotti, Claudia; Torelli, Riccardo; Sanguinetti, Maurizio; Ensoli, Fabrizio

doi:10.1016/j.ijid.2015.01.002

Cited by 21 publications

(17 citation statements)

References 17 publications

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“…In this work, 15 probes were used to rapidly screen the presence of relevant genes in the isolated S. uberis (Figure 2, Tables 2, 3). Four probes (U1, U2, A1, and A2) confirmed the isolate's identity as S. uberis by VITEK 2, a widely used phenotypic identification system that despite its usefulness shows some percentage of misidentifications (Di Domenico et al, 2015). The virulence-related genes hasA (probe V7), hasC (V1), gapC (V2), oppF (V3), sua (V4), and pauA (V6) were present in most of the S. uberis tested causing recurring infections, suggesting their importance for efficient S. uberis colonization.…”

Section: Discussionmentioning

confidence: 96%

Application of a Dot Blot Hybridization Platform to Assess Streptococcus uberis Population Structure in Dairy Herds

et al. 2017

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Streptococcus uberis is considered one of the most important pathogens associated with bovine mastitis. While traditionally acknowledged as an environmental pathogen, S. uberis has been shown to adopt a contagious epidemiological pattern in several dairy herds. Since different control strategies are employed depending on the mode of transmission, in-depth studies of S. uberis populations are essential to determine the best practices to control this pathogen. In this work, we optimized and validated a dot blot platform, combined with automatic image analysis, to rapidly assess the population structure of infective S. uberis, and evaluated its efficiency when compared to multilocus sequence analysis (MLSA) genotyping. Two dairy herds with prevalent S. uberis infections were followed in a 6 month period, in order to collect and characterize isolates from cows with persistent infections. These herds, located in Portugal (Barcelos and Maia regions), had similar management practices, with the herd from Barcelos being smaller and having a better milking parlor management, since infected cow segregation was immediate. A total of 54 S. uberis isolates were obtained from 24 different cows from the two herds. To overcome operator-dependent analysis of the dot blots and increase the technique's consistency and reliability, the hybridization signals were converted into probability values, with average probabilities higher than 0.5 being considered positive results. These data allowed to confirm the isolates' identity as S. uberis using taxa-specific markers and to determine the presence of virulence- and antibiotic resistance-related genes. In addition, MLSA allowed to disclose the most prevalent S. uberis clonal lineages in both herds. Seven different clusters were identified, with Barcelos showing a high clonal diversity and Maia a dominant lineage infecting most cows, suggesting distinct epidemiological patterns, with S. uberis displaying an environmental or contagious transmission pattern depending on the herd. Overall, this work showed the utility of dot blot and MLSA to characterize population structure and epidemiological patterns of mastitis-causing S. uberis. This approach allowed to disclose prevalent virulence patterns and clonal lineages of S. uberis in two distinct herds, and gain insights on the impact of herd management practices on pathogen population structure.

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Section: Discussionmentioning

confidence: 96%

Application of a Dot Blot Hybridization Platform to Assess Streptococcus uberis Population Structure in Dairy Herds

et al. 2017

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“…Additional confirmation tests for MRSA, such as agglutination tests for Penicillin-Binding Protein (PBP2, Oxoid, Basingstoke, UK) and cefoxitin screening, were performed. The automatic VITEK ® 2 (bioMérieux, Bagno a Ripoli, Italia) was used for the identification of the bacterial species and for the definition of the specific antimicrobial susceptibility tests [105], according to The European Committee on Antimicrobial Susceptibility Testing (EUCAST Clinical Breakpoint Table v 7.1). In case of vancomycin resistant S. aureus strains, identified by VITEK ® 2 (bioMérieux, Bagno a Ripoli, Italia), the antimicrobial susceptibility was further verified by the minimal inhibitory concentration methods (Thermo Scientific, Basingstoke, UK).…”

Section: Methodsmentioning

confidence: 99%

Biofilm is a Major Virulence Determinant in Bacterial Colonization of Chronic Skin Ulcers Independently from the Multidrug Resistant Phenotype

Domenico

Farulla

Prignano

et al. 2017

IJMS

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107

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Bacterial biofilm is a major factor in delayed wound healing and high levels of biofilm production have been repeatedly described in multidrug resistant organisms (MDROs). Nevertheless, a quantitative correlation between biofilm production and the profile of antimicrobial drug resistance in delayed wound healing remains to be determined. Microbial identification, antibiotic susceptibility and biofilm production were assessed in 135 clinical isolates from 87 patients. Gram-negative bacteria were the most represented microorganisms (60.8%) with MDROs accounting for 31.8% of the total isolates. Assessment of biofilm production revealed that 80% of the strains were able to form biofilm. A comparable level of biofilm production was found with both MDRO and not-MDRO with no significant differences between groups. All the methicillin-resistant Staphylococcus aureus (MRSA) and 80% of Pseudomonas aeruginosa MDR strains were found as moderate/high biofilm producers. Conversely, less than 17% of Klebsiella pneumoniae extended-spectrum beta-lactamase (ESBL), Escherichia coli-ESBL and Acinetobacter baumannii were moderate/high biofilm producers. Notably, those strains classified as non-biofilm producers, were always associated with biofilm producer bacteria in polymicrobial colonization. This study shows that biofilm producers were present in all chronic skin ulcers, suggesting that biofilm represents a key virulence determinant in promoting bacterial persistence and chronicity of ulcerative lesions independently from the MDRO phenotype.

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“…Blood cultures from each patient were assessed in the Laboratory of Clinical Microbiology, Virology and Bioemergencies -ASST Fatebenefratelli-Sacco using the BacT ALERT 3D (Biomerieux, Marcy-l'Etoile, France) automatized blood culture system. Microbial identification was performed by matrix-assisted laser desorption/ionisationtime of flight mass spectrometry (MALDI-TOF MS system -Bruker Daltonics, Bremen, Germany) and by sequence analysis (ABI PRISM 3130xl Genetic Analyzer) of the 16S rRNA gene [75]. Antimicrobial susceptibility testing (AST) was performed by the Vitek 2.0 system (Biomerieux, Marcy-l'Etoile, France) and by the broth microdilution test (Thermo Scientific, Massachusetts, USA) for the definition of the Minimum Inhibitory Concentration (MIC) criteria, according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST clinical breakpoint table v 9.0).…”

Section: Microbiological Diagnosismentioning

confidence: 99%

Microbial biofilm correlates with an increased antibiotic tolerance and poor therapeutic outcome in infective endocarditis

et al. 2019

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Background: Infective endocarditis (IE) is associated with high rates of mortality. Prolonged treatments with highdose intravenous antibiotics often fail to eradicate the infection, frequently leading to high-risk surgical intervention. By providing a mechanism of antibiotic tolerance, which escapes conventional antibiotic susceptibility profiling, microbial biofilm represents a key diagnostic and therapeutic challenge for clinicians. This study aims at assessing a rapid biofilm identification assay and a targeted antimicrobial susceptibility profile of biofilm-growing bacteria in patients with IE, which were unresponsive to antibiotic therapy. Results: Staphylococcus aureus was the most common isolate (50%), followed by Enterococcus faecalis (25%) and Streptococcus gallolyticus (25%). All microbial isolates were found to be capable of producing large, structured biofilms in vitro. As expected, antibiotic treatment either administered on the basis of antibiogram or chosen empirically among those considered first-line antibiotics for IE, including ceftriaxone, daptomycin, tigecycline and vancomycin, was not effective at eradicating biofilm-growing bacteria. Conversely, antimicrobial susceptibility profile of biofilm-growing bacteria indicated that teicoplanin, oxacillin and fusidic acid were most effective against S. aureus biofilm, while ampicillin was the most active against S. gallolyticus and E. faecalis biofilm, respectively. Conclusions: This study indicates that biofilm-producing bacteria, from surgically treated IE, display a high tolerance to antibiotics, which is undetected by conventional antibiograms. The rapid identification and antimicrobial tolerance profiling of biofilm-growing bacteria in IE can provide key information for both antimicrobial therapy and prevention strategies.

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Misidentification of Streptococcus uberis as a Human Pathogen: A Case Report and Literature Review

Cited by 21 publications

References 17 publications

Application of a Dot Blot Hybridization Platform to Assess Streptococcus uberis Population Structure in Dairy Herds

Application of a Dot Blot Hybridization Platform to Assess Streptococcus uberis Population Structure in Dairy Herds

Biofilm is a Major Virulence Determinant in Bacterial Colonization of Chronic Skin Ulcers Independently from the Multidrug Resistant Phenotype

Microbial biofilm correlates with an increased antibiotic tolerance and poor therapeutic outcome in infective endocarditis

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