ABSTRACT
Bordetella pertussis not expressing pertactin has increased in countries using acellular pertussis vaccines (ACV). The deficiency is mostly caused by pertactin gene disruption by IS481. To assess the effect of the transition from whole-cell vaccine to ACV on the emergence of B. pertussis not expressing pertactin in Spain, we studied 342 isolates collected during 1986-2018. We identified 93 pertactin-deficient isolates. All were detected after introduction of ACV and represented 38% of isolates collected during the ACV period; 58.1% belonged to a genetic cluster of isolates carrying the unusual prn::del(-292, 1340) mutation. Pertactin inactivation by IS481 insertion was identified in 23.7% of pertactin-deficient isolates, arising independently multiple times and in different phylogenetic branches. Our findings support the emergence and dissemination of a cluster of B. pertussis with an infrequent mechanism of pertactin disruption in Spain, probably resulting from introduction of ACV.
Subject(s)
Bordetella pertussis , Whooping Cough , Bacterial Outer Membrane Proteins/genetics , Humans , Pertussis Vaccine , Phylogeny , Spain/epidemiology , Virulence Factors, Bordetella/genetics , Whooping Cough/epidemiology , Whooping Cough/prevention & controlABSTRACT
The aim of this study is to review bacterial isolates from respiratory samples of patients with severe COVID-19 disease during the first 2 months of the first wave in our hospital. A single-center retrospective observational study in critically ill adult patients was performed. A total of 1251 respiratory samples from 1195 patients were processed. Samples from 66 patients (5.52%) were determined to be microbiologically significant by a semi-quantitative culture. All patients received broad spectrum antibiotherapy as an empirical treatment. The isolated bacteria were mainly Enterobacterales followed by Staphylococcus aureus and Pseudomonas aeruginosa. Bacterial co-infections in ICU stay could seem not dependent on the virus that has produced the viral pneumonia similarly as with other respiratory viruses such as Influenza virus.
Subject(s)
COVID-19/complications , Coinfection/diagnosis , Pneumonia, Bacterial/complications , Tertiary Care Centers , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Cross Infection/drug therapy , Cross Infection/microbiology , Female , Humans , Intensive Care Units , Male , Middle Aged , Retrospective Studies , Risk Factors , SARS-CoV-2ABSTRACT
BACKGROUND: The objective of this study was to evaluate the virulence of P. aeruginosa ventilator-associated pneumonia (VAP) strains (cases) in terms of biofilm production and other phenotypic and genotypic virulence factors compared to P. aeruginosa strains isolated from other infections (controls). METHODS: Biofilm production was tested to assess biomass production and metabolic activity using crystal violet binding assay and XTT assay, respectively. Pigment production (pyocyanin and pyoverdine) was evaluated using cetrimide agar. Virulence genes were detected by conventional multiplex PCR and virulence was tested in an in vivo model in Galleria mellonella larvae. RESULTS: We did not find statistically significant differences between VAP and no-VAP strains (p > 0.05) regarding biofilm production. VAP strains had no production of pyocyanin after 24 h of incubation (p = 0.023). The distribution of virulence genes between both groups were similar (p > 0.05). VAP strains were less virulent than non-VAP strains in an in vivo model of G. mellonella (p < 0.001). CONCLUSION: The virulence of VAP-Pseudomonas aeruginosa does not depend on biofilm formation, production of pyoverdine or the presence of some virulence genes compared to P. aeruginosa isolated from non-invasive locations. However, VAP strains showed attenuated virulence compared to non-VAP strains in an in vivo model of G. mellonella.
Subject(s)
Pneumonia, Ventilator-Associated/microbiology , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/pathogenicity , Biofilms , Genotype , Humans , Multiplex Polymerase Chain Reaction , Oligopeptides/metabolism , Phenotype , Pseudomonas aeruginosa/metabolism , Pyocyanine/metabolism , Ventilators, Mechanical/adverse effects , Virulence/genetics , Virulence Factors/geneticsABSTRACT
We report a case of an immunocompetent woman with atypical marginal keratitis. She presented with recurrent episodes of multiples microabscess distributed in a triangular pattern associated with stromal oedema and anterior chamber uveitis, affecting both eyes, but not simultaneously. The episodes responded to steroid drops, corneal inflammation was coincidental with a worsening of her blepharitis in the affected eye and S. aureus was isolated from the lids.
Subject(s)
Abscess/etiology , Blepharitis/complications , Eye Infections, Bacterial/microbiology , Keratitis/etiology , Staphylococcal Infections/microbiology , Staphylococcus aureus/isolation & purification , Uveitis/etiology , Abscess/diagnosis , Abscess/microbiology , Blepharitis/diagnosis , Blepharitis/microbiology , Corneal Stroma/microbiology , Corneal Stroma/pathology , Eye Infections, Bacterial/diagnosis , Female , Humans , Keratitis/diagnosis , Middle Aged , Staphylococcal Infections/diagnosis , Uveitis/diagnosis , Uveitis/microbiologyABSTRACT
A disposable PCR-based amperometric magneto-genosensor for detection and identification of Streptococcus pneumoniae was evaluated. ROC curve analysis used to determine optimal signal cutoff values yielded a sensitivity of 91% and a specificity of 90%. The method was also tested for the direct detection of pneumococci in clinical samples.
Subject(s)
Biosensing Techniques , Pneumococcal Infections/diagnosis , Streptococcus pneumoniae/genetics , Genes, Bacterial , Humans , Polymerase Chain Reaction/methods , ROC Curve , Reproducibility of ResultsABSTRACT
The mechanisms of linezolid resistance among 86 staphylococcal isolates from two intensive care units were investigated. The most frequent was the G2576T mutation in the 23S rRNA (82%). The cfr gene was found in 17% of the isolates, seven S. aureus and eight S. epidermidis isolates. Four of the S. epidermidis isolates had the G2576T mutation and the cfr gene. In four S. haemolyticus isolates, the mechanism could not be identified.
Subject(s)
Acetamides/pharmacology , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial , Oxazolidinones/pharmacology , Staphylococcal Infections/microbiology , Staphylococcus aureus/drug effects , Staphylococcus epidermidis/drug effects , Staphylococcus haemolyticus/drug effects , Bacterial Proteins/genetics , Humans , Intensive Care Units , Linezolid , Point Mutation , RNA, Ribosomal, 23S/genetics , Staphylococcus aureus/genetics , Staphylococcus aureus/isolation & purification , Staphylococcus epidermidis/genetics , Staphylococcus epidermidis/isolation & purification , Staphylococcus haemolyticus/genetics , Staphylococcus haemolyticus/isolation & purification , Tertiary Care CentersABSTRACT
A linezolid-resistant, methicillin-susceptible isolate of Staphylococcus aureus was obtained from an infected surgical wound in an ambulatory patient. The isolate belonged to ST125 and was susceptible to all the antibiotics tested except linezolid (MIC 8 µg/ml) and levofloxacin. Linezolid resistance could be ascribed to the presence of the mutation G2576T in 2 of the 23S rRNA alleles. The mutant alleles were stably maintained in the absence of antibiotic selection.
Subject(s)
Acetamides/pharmacology , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial , Oxazolidinones/pharmacology , Staphylococcal Infections/microbiology , Staphylococcus aureus/drug effects , Aged, 80 and over , Female , Humans , Linezolid , Methicillin/pharmacology , Microbial Sensitivity Tests , Outpatients , Oxazolidinones/therapeutic use , Point Mutation , RNA, Ribosomal, 23S/genetics , Staphylococcal Infections/drug therapy , Staphylococcus aureus/isolation & purification , Surgical Wound Infection/drug therapy , Surgical Wound Infection/microbiologyABSTRACT
Serum galactomannan antigen detection was used for the diagnosis and follow-up of cardiac aspergillosis after surgery in 2 nonneutropenic patients. The galactomannan index, developed in response to surgical and antifungal therapies, could prove to be a valuable method for the diagnosis and follow-up of fungal infections in such patients.
