Role Of Biofilm Formation In Ureaplasma Species Antibiotic Susceptibility, And Development Of Bronchopulmonary Dysplasia (BPD) In Preterm Neonates

Abstract Methicillin-Resistant Staphylococcus aureus (MRSA) is a significant threat to human health. Additionally, biofilm forming bacteria becomes more tolerant to antibiotics and act as bacterial reservoir leading to chronic infection. In this study, we characterised the antibiotic susceptibility, biofilm production and sequence types (ST) of 74 randomly selected clinical isolates of S. aureus causing ocular infections. Antibiotic susceptibility revealed 74% of the isolates as resistant against one or two antibiotics, followed by 16% multidrug-resistant isolates (MDR), and 10% sensitive. The isolates were characterized as MRSA (n = 15), Methicillin-sensitive S. aureus (MSSA, n = 48) and oxacillin susceptible mecA positive S. aureus (OS-MRSA, n = 11) based on oxacillin susceptibility, mecA gene PCR and PBP2a agglutination test. All OS-MRSA would have been misclassified as MSSA on the basis of susceptibility test. Therefore, both phenotypic and genotypic tests should be included to prevent strain misrepresentation. In addition, in-depth studies for understanding the emerging OS-MRSA phenotype is required. The role of fem XAB gene family has been earlier reported in OS-MRSA phenotype. Sequence analysis of the fem XAB genes revealed mutations in fem × (K3R, H11N, N18H and I51V) and fem B (L410F) genes. The fem XAB genes were also found down-regulated in OS-MRSA isolates in comparison to MRSA. In OS-MRSA isolates, biofilm formation is regulated by fibronectin binding proteins A & B. Molecular typing of the isolates revealed genetic diversity. All the isolates produced biofilm, however, MRSA isolates with strong biofilm phenotype represent a worrisome situation and may even result in treatment failure.

Download Full-text

Oxidative and Proteolytic Inactivation of Alpha-1 Antitrypsin in Bronchopulmonary Dysplasia Pathogenesis: A Top-Down Proteomic Bronchoalveolar Lavage Fluid Analysis

Frontiers in Pediatrics ◽

10.3389/fped.2021.597415 ◽

2021 ◽

Vol 9 ◽

Author(s):

Chiara Tirone ◽

Federica Iavarone ◽

Milena Tana ◽

Alessandra Lio ◽

Claudia Aurilia ◽

...

Keyword(s):

Bronchoalveolar Lavage ◽

Bronchopulmonary Dysplasia ◽

Bronchoalveolar Lavage Fluid ◽

Lavage Fluid ◽

Small Sample ◽

Preterm Neonates ◽

Ionization Mass ◽

Top Down ◽

Alpha 1 Antitrypsin

The study investigates the role of the oxidative and proteolytic inactivation of alpha-1 antitrypsin (AAT) in the pathogenesis of bronchopulmonary dysplasia (BPD) in premature infants. Bronchoalveolar lavage fluid (BALF) samples were collected on the 3rd day of life from mechanically ventilated neonates with gestational age ≤ 30 weeks and analyzed without previous treatment (top-down proteomics) by reverse-phase high-performance liquid chromatography-electrospray ionization mass spectrometry. AAT fragments were identified by high-resolution LTQ Orbitrap XL experiments and the relative abundances determined by considering the extracted ion current (XIC) peak area. Forty preterm neonates were studied: 20 (50%) did not develop BPD (no-BPD group), 17 (42.5%) developed mild or moderate new-BPD (mild + moderate BPD group), and 3 (7.5%) developed severe new-BPD (severe BPD group). Eighteen fragments of AAT and a fragment of AAT oxidized at a methionine residue were identified: significantly higher values of AAT fragments 25–57, 375–418, 397–418, 144–171, and 397–418 with oxidized methionine were found in the severe BPD group. The significantly higher levels of several AAT fragments and of the fragment 397–418, oxidized in BALF of preterm infants developing BPD, underlie the central role of an imbalance between proteases and protease inhibitors in exacerbating lung injury and inducing most severe forms of BPD. The study has some limitations, and between them, the small sample size implies the need for further confirmation by larger studies.

Download Full-text

Reference: The role of corticosteroids in a preterm infant with lung pathology in the first three months of life.

10.31219/osf.io/6a8tg ◽

2021 ◽

Author(s):

Femi Adeniyi

Keyword(s):

Bronchopulmonary Dysplasia ◽

Scientific Evidence ◽

Extensive Study ◽

Preterm Neonates ◽

Lung Pathology ◽

Selective Treatment ◽

Term Outcome ◽

Long Term Outcome

Corticosteroids are helpful in the treatment of preterm neonates at risk of bronchopulmonary dysplasia (BPD). However, its usefulness depends on patient selection, the timing of intervention with a corticosteroid, and choice of corticosteroid. In making these clinical choices, one must consider both short and long-term outcomes. Although corticosteroid use has been available for decades in preterm neonatal care, many aspects of corticosteroid use are unresolved due to limited research. Corticosteroids cause upregulation of anti-inflammatory, inhibiting pro-inflammatory mediators at the genomic level. Furthermore, the benefits of using corticosteroids should outweigh the known risks. Here we will discuss the current literature to guide clinical practice—a literature search for evidence through the clinical database on EMBASE, Medline, PubMed, and Cochrane. The keywords are bronchopulmonary dysplasia, corticosteroids, and prematurity.Limitations.There is bias due to limited research available to provide a high level of scientific evidence on the use of different modes of administration, other agents compared to the systemic use of dexamethasone. Conclusion.The consensus in the prevention of BPD is selective treatment after one week of life with dexamethasone. There is limited evidence to suggest the role of prophylaxis hydrocortisone in preventing BPD and advise to be considered in centers with a high risk of BPD. An extensive study into prophylaxis hydrocortisone for prevention of BDP and long-term outcome appears to be promising.The role of instilled steroids with surfactants at birth appears promising in the single-center study. A multicentre double-blinded randomized intratracheal budesonide use at delivery will be valuable.

Download Full-text

Biofilm-Induced Antibiotic Resistance in Clinical Acinetobacter baumannii Isolates

Antibiotics ◽

10.3390/antibiotics9110817 ◽

2020 ◽

Vol 9 (11) ◽

pp. 817

Author(s):

Abebe Mekuria Shenkutie ◽

Mian Zhi Yao ◽

Gilman Kit-hang Siu ◽

Barry Kin Chung Wong ◽

Polly Hang-mei Leung

Keyword(s):

Antibiotic Resistance ◽

Acinetobacter Baumannii ◽

Antibiotic Susceptibility ◽

Biofilm Formation ◽

Multidrug Resistant ◽

Antibiotic Tolerance ◽

Planktonic Cells ◽

Antibiotic Susceptibilities ◽

Extensively Drug Resistant

In order to understand the role of biofilm in the emergence of antibiotic resistance, a total of 104 clinical Acinetobacter baumannii strains were investigated for their biofilm-forming capacities and genes associated with biofilm formation. Selected biofilm-formers were tested for antibiotic susceptibilities when grown in biofilm phase. Reversibility of antibiotic susceptibility in planktonic cells regrown from biofilm were investigated. We found 59.6% of the strains were biofilm-formers, among which, 66.1% were non-multidrug resistant (MDR) strains. Presence of virulence genes bap, csuE, and abaI was significantly associated with biofilm-forming capacities. When strains were grown in biofilm state, the minimum biofilm eradication concentrations were 44, 407, and 364 times higher than the minimum bactericidal concentrations (MBC) for colistin, ciprofloxacin, and imipenem, respectively. Persisters were detected after treating the biofilm at 32–256 times the MBC of planktonic cells. Reversibility test for antibiotic susceptibility showed that biofilm formation induced reversible antibiotic tolerance in the non-MDR strains but a higher level of irreversible resistance in the extensively drug-resistant (XDR) strain. In summary, we showed that the non-MDR strains were strong biofilm-formers. Presence of persisters in biofilm contributed to the reduced antibiotic susceptibilities. Biofilm-grown Acinetobacter baumannii has induced antibiotic tolerance in non-MDR strains and increased resistance levels in XDR strains. To address the regulatory mechanisms of biofilm-specific resistance, thorough investigations at genome and transcription levels are warranted.

Download Full-text

Overexpression of Spock2 in mice leads to altered lung alveolar development and worsens lesions induced by hyperoxia

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00191.2019 ◽

2020 ◽

Vol 319 (1) ◽

pp. L71-L81 ◽

Cited By ~ 1

Author(s):

Alice Hadchouel ◽

Marie-Laure Franco-Montoya ◽

Sophie Guerin ◽

Marcio Do Cruzeiro ◽

Mickaël Lhuillier ◽

...

Keyword(s):

Bronchopulmonary Dysplasia ◽

Lung Development ◽

Transgenic Mouse Model ◽

Matrix Metalloproteinase 2 ◽

Preterm Neonates ◽

Alveolar Cells ◽

Very Preterm ◽

Rat Pups ◽

Alveolar Development

SPARC/osteonectin, cwcv and kazal-like domains proteoglycan 2 ( SPOCK2) was previously associated with genetic susceptibility to bronchopulmonary dysplasia in a French population of very preterm neonates. Its expression increases during lung development and is increased after exposure of rat pups to hyperoxia compared with controls bred in room air. To further investigate the role of SPOCK2 during lung development, we designed two mouse models, one that uses a specific anti-Spock2 antibody and one that reproduces the hyperoxia-induced Spock2 expression with a transgenic mouse model resulting in a conditional and lung-targeted overexpression of Spock2. When mice were bred under hyperoxic conditions, treatment with anti-Spock2 antibodies significantly improved alveolarization. Lung overexpression of Spock2 altered alveolar development in pups bred in room air and worsened hyperoxia-induced lesions. Neither treatment with anti-Spock2 antibody nor overexpression of Spock2 was associated with abnormal activation of matrix metalloproteinase-2. These two models did not alter the expression of known players in alveolar development. This study brings strong arguments for the deleterious role of SPOCK2 on lung alveolar development especially after lung injury, suggesting its role in bronchopulmonary dysplasia susceptibility. These effects are not mediated by a deregulation in metalloproteases activity and in expression of factors essential to normal alveolarization. The balance between types 1 and 2 epithelial alveolar cells may be involved.

Download Full-text

MicroRNA-214 promotes alveolarization in neonatal rat models of bronchopulmonary dysplasia via the PlGF-dependent STAT3 pathway

Molecular Medicine ◽

10.1186/s10020-021-00374-4 ◽

2021 ◽

Vol 27 (1) ◽

Author(s):

Zhi-Qun Zhang ◽

Hui Hong ◽

Jing Li ◽

Xiao-Xia Li ◽

Xian-Mei Huang

Keyword(s):

Epithelial Cells ◽

Bronchopulmonary Dysplasia ◽

Neonatal Rat ◽

Luciferase Reporter ◽

Preterm Neonates ◽

Neonatal Rats ◽

Rat Models ◽

Stat3 Pathway ◽

Pulmonary Epithelial Cells

Abstract Background Recently, the role of several microRNAs (miRNAs or miRs) in pulmonary diseases has been described. The molecular mechanisms by which miR-214 is possibly implicated in bronchopulmonary dysplasia (BPD) have not yet been addressed. Hence, this study aimed to investigate a putative role of miR-214 in alveolarization among preterm neonates with BPD. Methods Microarray-based gene expression profiling data from BPD was employed to identify differentially expressed genes. A BPD neonatal rat model was induced by hyperoxia. Pulmonary epithelial cells were isolated from rats and exposed to hyperoxia to establish cell injury models. Gain- and loss-of-function experiments were performed in BPD neonatal rats and hyperoxic pulmonary epithelial cells. MiR-214 and PlGF expression in BPD neonatal rats, and eNOS, Bcl-2, c-myc, Survivin, α-SMA and E-cadherin expression in hyperoxic pulmonary epithelial cells were measured using RT-qPCR and Western blot analysis. The interaction between PlGF and miR-214 was identified using dual luciferase reporter gene and RIP assays. IL-1β, TNF-a, IL-6, ICAM-1 and Flt-1 expression in the rat models was measured using ELISA. Results The lung tissues of neonatal rats with BPD showed decreased miR-214 expression with elevated PlGF expression. PlGF was found to be a target of miR-214, whereby miR-214 downregulated PlGF to inactivate the STAT3 pathway. miR-214 overexpression or PlGF silencing decreased the apoptosis of hyperoxic pulmonary epithelial cells in vitro and restored alveolarization in BPD neonatal rats. Conclusion Overall, the results demonstrated that miR-214 could facilitate alveolarization in preterm neonates with BPD by suppressing the PlGF-dependent STAT3 pathway.

Download Full-text