Publications by authors named "Asmaa Tazi"
Bacterial two-component systems (TCSs) are signaling modules that control physiology, adaptation, and host interactions. A typical TCS consists of a histidine kinase (HK) that activates a response regulator via phosphorylation in response to environmental signals. Here, we systematically test the effect of inactivating the conserved phosphatase activity of HKs to activate TCS signaling pathways.
View Article and Find Full Text PDFClinical emergence of a novel extended-spectrum variant deriving from the OXY-1 β-lactamase.
Eur J Clin Microbiol Infect Dis
November 2024
Article Synopsis
- Two clinical isolates of Klebsiella michiganensis from the same patient were genetically compared, revealing differing resistance profiles: one was resistant to piperacillin-tazobactam and intermediate to cefotaxime, while the other was resistant to ceftazidime but susceptible to piperacillin-tazobactam.
- * A mutation in the bla gene, resulting in a L169M change in the Ω loop, was identified as a key factor in the resistance differences.
- * Cloning experiments in E. coli demonstrated that this mutation allowed for increased resistance to ceftazidime and cefepime but reduced resistance to piperacillin-tazobactam, marking a novel discovery of how
Article Synopsis
- Group B Streptococcus (GBS), particularly the hypervirulent CC17 clone, is a major cause of neonatal meningitis linked to significant mortality and disability.
- This study examined how GBS CC17 interacts with the choroid plexus, a critical part of the blood-cerebrospinal fluid barrier, using both mouse models and in vitro cell studies.
- Results showed that GBS CC17 effectively invades choroid plexus cells through a specific mechanism, leading to immune responses and potential pathways for brain infections.
is among the few pathogens that have not developed resistance to ß-lactam antibiotics despite decades of clinical use. The molecular basis of this long-lasting susceptibility has not been investigated, and it is not known whether specific mechanisms constrain the emergence of resistance. In this study, we first report ß-lactam tolerance due to the inactivation of the c-di-AMP phosphodiesterase GdpP.
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- A study on Group B Streptococcus (GBS) neonatal infections in France from 2007 to 2021 found that out of 1,527 cases, 36 (2.36%) were recurrent infections.
- Recurrence was more common in preterm (68%) and low birthweight (72%) infants, with a significant association to the hypervirulent GBS clonal complex 17.
- No tolerant strains were found, and genome sequencing didn't identify specific recurrence traits, highlighting the need for larger studies on managing these rare cases.
Article Synopsis
- Group B Streptococcus (GBS) is a major cause of severe infections in newborns, and preventing these infections involves giving antibiotics to GBS-colonized pregnant women during labor.
- The study evaluated the effectiveness of two rapid tests, Ampliflash® GBS and PlusLife® GBS, for detecting GBS in vaginal samples, comparing them with traditional culture methods.
- Results showed that both tests were highly sensitive and specific, providing quick results within 10 to 35 minutes, indicating they could be more efficient in preventing GBS-related neonatal diseases than current screening methods, but further research is necessary.
Article Synopsis
- Systematic cultures of central line tips in NICUs may not be as clinically useful due to high bacterial contamination rates during removal, leading to debate on their necessity.
- A retrospective study analyzed infections and bacterial colonization in 375 newborns with central catheters, finding a 43% colonization rate and 31 confirmed catheter-related infections among suspected sepsis cases.
- The study suggests that only culturing catheters when infections are suspected could be a more efficient approach than routine screening, as antibiotic effectiveness did not significantly differ between expert recommendations and actual prescriptions.
Article Synopsis
- Group B Streptococcus (GBS), particularly the capsular serotype III called CC17, is a major cause of serious infections like bacteremia and meningitis in newborns, being labeled as a hypervirulent clone.
- The study found that CC17 strains are engulfed (phagocytosed) more effectively by human monocytes and macrophages compared to non-CC17 strains, due to enhanced attachment facilitated by specific proteins (HvgA and PI-2b pilus).
- Despite being phagocytosed more efficiently, both CC17 and non-CC17 strains survive similarly within immune cells, suggesting that CC17's enhanced phagocytosis might help it evade the immune system and persist in the
[Integrating pathology and biology into medical education: current state and future directions].
Ann Biol Clin (Paris)
February 2024
Pathology and biology are essential in the patient care. However, they suffer from a lack of attractiveness to medicine students. In order to gain insight and improve the visibility and attractiveness of these specialties, we designed a survey and submitted forms to medical students, laboratory medical staff, and clinical staff from the different hospitals and institutes attached to "Université Paris Cité".
View Article and Find Full Text PDFAim: Clusters of group B Streptococcus (GBS) infections in neonatal intensive care units (NICU) are poorly documented. We aimed to assess GBS cross-transmission during an outbreak of GBS sepsis.
Methods: The study was carried out between October and November 2021 in a French University Hospital.
A LAMP-based assay for the molecular detection of group B Streptococcus.
Eur J Clin Microbiol Infect Dis
October 2023
Purpose: Streptococcus agalactiae remains a major pathogen in human health, especially in neonatal infection. Detection in pregnant women is essential to initiate intrapartum antibiotic prophylaxis. This study compared the HiberGene loop-mediated isothermal amplification (LAMP) assay to culture, the reference method, for the detection of group B Streptococcus (GBS) in pregnant women.
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- The vaginal microbiota consists of microorganisms in the vagina that play a crucial role in women's reproductive and overall health, primarily characterized by Lactobacillus species.
- Disruptions to the vaginal microbiota, caused by factors like antibiotics, sexual activity, and hormonal changes, can lead to conditions such as bacterial vaginosis, especially impactful during pregnancy.
- A study involving 749 pregnant women found that low diversity in the vaginal microbiota, particularly a depletion of Lactobacilli, is linked to an increased risk of preterm delivery, suggesting that overall diversity, rather than specific species, is a better risk indicator.
Article Synopsis
- - Non-beta-hemolytic streptococci (NBHS) are often overlooked as serious pathogens in invasive diseases, notably affecting older and immunocompromised individuals.
- - A study by the French National Reference Center for Streptococci revealed 522 invasive NBHS cases, with the most common types being Streptococcus anginosus, Streptococcus mitis, and Streptococcus sanguinis, and a notable proportion of infections led to severe conditions like bacteremia and endocarditis.
- - Many NBHS strains show resistance to commonly used antibiotics, especially beta-lactams, complicating treatment; however, they were generally susceptible to glycopeptides, highlighting the need for better detection methods for resistant strains
Article Synopsis
- KP (Klebsiella pneumoniae) is the leading cause of endogenous endophthalmitis (EE) in Asia, and this study looks at eight cases from France, indicating it may be on the rise in Europe.
- Researchers analyzed EE cases from 2014 to 2021, finding that 24% were caused by KP, primarily the hypervirulent strain, with most cases occurring recently.
- Patients with KP EE often had multiple infections outside the eyes, particularly notable liver abscesses, and a significant portion also experienced cerebral complications, with poor visual outcomes for all involved.
Group B Streptococcus (GBS) is the leading cause of neonatal infections and an important pathogen in pregnancy. However, the features of pregnancy-associated infections are poorly reported. We analyzed 336 cases of GBS invasive infections in women aged 18-50 years, including 242 (72.
View Article and Find Full Text PDFObjective: Type 1 diabetes (T1D) is an autoimmune disease caused by the destruction of pancreatic β-cells producing insulin. Both T1D patients and animal models exhibit gut microbiota and mucosa alterations, although the exact cause for these remains poorly understood. We investigated the production of key cytokines controlling gut integrity, the abundance of segmented filamentous bacteria (SFB) involved in the production of these cytokines, and the respective role of autoimmune inflammation and hyperglycaemia.
View Article and Find Full Text PDFGroup B Streptococcus (GBS) is the major cause of human neonatal infections. A single clone, designated CC17-GBS, accounts for more than 80% of meningitis cases, the most severe form of the infection. However, the events allowing blood-borne GBS to penetrate the brain remain largely elusive.
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