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Frontiers in Cellular and Infection... 2024The hemin acquisition system is composed of an outer membrane TonB-dependent transporter that internalizes hemin into the periplasm, periplasmic hemin-binding proteins...
INTRODUCTION
The hemin acquisition system is composed of an outer membrane TonB-dependent transporter that internalizes hemin into the periplasm, periplasmic hemin-binding proteins to shuttle hemin, an inner membrane transporter that transports hemin into the cytoplasm, and cytoplasmic heme oxygenase to release iron. Fur and HemP are two known regulators involved in the regulation of hemin acquisition. The hemin acquisition system of is poorly understood, with the exception of HemA as a TonB-dependent transporter for hemin uptake.
METHODS
Putative candidates responsible for hemin acquisition were selected via a homolog search and a whole-genome survey of . Operon verification was performed by reverse transcription-polymerase chain reaction. The involvement of candidate genes in hemin acquisition was assessed using an in-frame deletion mutant construct and iron utilization assays. The transcript levels of candidate genes were determined using quantitative polymerase chain reaction.
RESULTS
and operons were selected as candidates for hemin acquisition. Compared with the parental strain, and mutants displayed a defect in their ability to use hemin as the sole iron source for growth. However, hemin utilization by the and mutants was comparable to that of the parental strain. expression was repressed by Fur in iron-replete conditions and derepressed in iron-depleted conditions. HemP negatively regulated expression. Like , was repressed by Fur in iron-replete conditions; however, was moderately derepressed in response to iron-depleted stress and fully derepressed when hemin was present. Unlike and , the operon was constitutively expressed, regardless of the iron level or the presence of hemin, and Fur and HemP had no influence on its expression.
CONCLUSION
HemA, HemU, and TonB1 contribute to hemin acquisition in . Fur represses the expression of and in iron-replete conditions. expression is regulated by low iron levels, and HemP acts as a negative regulator of this regulatory circuit. expression is regulated by low iron and hemin levels in a -dependent manner.
Topics: Hemin; Stenotrophomonas maltophilia; Bacterial Proteins; Membrane Proteins; Iron
PubMed: 38596648
DOI: 10.3389/fcimb.2024.1380976 -
Wiadomosci Lekarskie (Warsaw, Poland :... 2024Aim: To determine the current prevalence of endometritis after hysteroscopic procedures and antimicrobial resistance of responsible pathogens in Ukraine.
OBJECTIVE
Aim: To determine the current prevalence of endometritis after hysteroscopic procedures and antimicrobial resistance of responsible pathogens in Ukraine.
PATIENTS AND METHODS
Materials and Methods: Multicenter prospective cohort study was conducted from January 2020 to December 2022 in fifteen hospitals from twelve regions of Ukraine. Definitions of endometritis were adapted from the Centers for Disease Control and Prevention's National Healthcare Safety Network. Antibiotic susceptibility was done by the disc diffusion test as recommended by EUCAST.
RESULTS
Results: Among 13,872 patients with hysteroscopic procedures, 1027 (7.4%) endometritis were observed. Of these cases, 0.4% were detected after diagnostic hysteroscopy, and 7.0% were detected after operative hysteroscopy. Of all endometritis cases, 64.2% were detected after hospital discharge. The most commonly reported bacterial species were Escherichia coli (24.3%), followed by Enterobacter spp. (12.7%), Enterococcus spp. (8.3%), Pseudomonas aeruginosa (8.1%), Serratia marcescens (6.8%), Staphylococcus aureus (5.9%), Proteus mirabilis (5.8%), Klebsiella oxytoca (5.1%), Stenotrophomonas maltophilia (4.5%), Klebsiella pneumoniae (4.1%). A significant proportion of patients were affected by endometritis caused by bacteria developed resistance to several antimicrobials, varying widely depending on the bacterial species, antimicrobial group, and geographical region of Ukraine.
CONCLUSION
Conclusions: Our data suggest a high prevalence of endometritis after hysteroscopic procedures. Risk for endometritis was higher after operative hysteroscopy compared with diagnostic hysteroscopy. Many most of patients were affected by endometritis caused by bacteria developed resistance to several antimicrobials. These data underscore the importance of tracking antimicrobial resistance of responsible pathogens of HAIs in hospitals.
Topics: Female; Humans; Endometritis; Prospective Studies; Ukraine; Drug Resistance, Bacterial; Bacteria; Anti-Infective Agents; Escherichia coli; Anti-Bacterial Agents
PubMed: 38592977
DOI: 10.36740/WLek202402101 -
Materia Socio-medica 2024The rate of multi-drug antibiotic resistance in nosocomial bloodstream infections in elderly patients is increasing. This study examined the data for bloodstream...
BACKGROUND
The rate of multi-drug antibiotic resistance in nosocomial bloodstream infections in elderly patients is increasing. This study examined the data for bloodstream infections to gain a better understanding of bacterial antibiotic resistance.
METHODS
This was a retrospective study of 817 patients with the first positive blood culture between January 1, 2016 and December 31, 2019.
RESULTS
Moyen's age was 77.4 ± 9.8 years, male (52.4%) and SOFA 5.0 ± 4. ESBL(+) rate was 78/817 (9.5%). ESBL(+) rate for Escherichia coli and Klebsiella pneumoniae was 69/141 (48.9%) and 9/52 (17.3%), respectively. The most common isolates were Escherichia coli (17.3%), Stenotrophomonas maltophilia (13.7%), and Staphylococcus species (23.1%). The rate of septic shock and mortality accounted for 22.3% and 28.9%, respectively. Escherichia coli is highly sensitive to carbapenem, and resistant (>50%) with quinolone and aminoside. Klebsiella pneumoniae and Pseudomonas aeruginosa were highly sensitive to carbapenem. Acinetobacter baumannii was resistant to meropenem (75%). Stenotrophomonas maltophilia was sensitive to quinolone (13.8 %), and highly resistant to remaining antibiotics. Methicillin-resistant Staphylococcus aureus had a low resistance rate for vancomycin, teicoplanin, and linezolid. Multivariate analysis showed that the significant factors associated with mortality were age >75; SOFA >7; respiratory infection; intensive care unit treatment and presentation with septic shock.
CONCLUSION
The mortality rate was still high, especially for antibiotic-resistant agents.
PubMed: 38590604
DOI: 10.5455/msm.2024.36.82-89 -
Infection Apr 2024Bronchoalveolar lavage is commonly used in clinical practice for unresolved pneumonia. However, bronchoalveolar lavage is not suitable for all patients as it is an...
PURPOSE
Bronchoalveolar lavage is commonly used in clinical practice for unresolved pneumonia. However, bronchoalveolar lavage is not suitable for all patients as it is an invasive procedure and can worsen oxygenation. The diagnostic value of bronchial wash and sputum has been debated extensively over the years. In this study, we aim to compare the diagnostic value in several pathogens of bronchoalveolar lavage and bronchial wash, and secondarily bronchoalveolar lavage and sputum.
METHODS
We retrospectively included all adult patients in our hospital who underwent bronchoalveolar lavage, bronchial wash, and where sputum sampling was done between January 1st of 2018 and December 31st of 2021. The intraclass correlation coefficient was computed for the three tests.
RESULTS
In total, 308 patients were included. We found a level of correlation of 0.819 and 0.865, respectively, between bronchoalveolar lavage and bronchial wash for two pathogens: Staphylococcus aureus and Pseudomonas aeruginosa. For Stenotrophomonas maltophilia and Aspergillus fumigatus, we found an intraclass correlation coefficient of 0.568 and 0.624, respectively. Between bronchoalveolar lavage and sputum, we found varying levels of agreement.
CONCLUSION
Our study shows reasonably well agreement levels between bronchoalveolar lavage and bronchial wash, suggesting that bronchial wash could potentially be an alternative to bronchoalveolar lavage.
PubMed: 38589747
DOI: 10.1007/s15010-024-02238-5 -
Nanowarriors from Mentha: Unleashing Nature's Antimicrobial Arsenal with Cerium Oxide Nanoparticles.ACS Omega Apr 2024Medicinal plant-based cerium oxide nanoparticles (CeONPs) possessed excellent antimicrobial properties against multiple strains of Gram-positive and Gram-negative...
Medicinal plant-based cerium oxide nanoparticles (CeONPs) possessed excellent antimicrobial properties against multiple strains of Gram-positive and Gram-negative bacteria. The CeONPs are popular because their electropositive charged surface causes oxidation of plasma membrane and facilitates the penetration of CeONPs inside the pathogen body. In the present research work, CeONPs stabilized with Mentha leaf extract; as a result, nanoparticles surface-bonded with various functional groups of phytochemicals which enhanced the therapeutic potential of CeONPs. The inhibition percentage of CeONPs was evaluated against eight pathogenic Gram-positive bacteria and Gram-negative bacteria , , sp., sp., and and plant bacteria sp. The antifungal properties of CeONPs were evaluated against three pathogenic fungal species , , and via the streak plate method. The antimicrobial inhibitory activity of CeONPs was good to excellent. The current research work clearly shows that three different medicinal plants , , and based CeONPs, variation in nanoparticle sizes, and surface-to-volume ratio of green CeONPs are three factors responsible to generate and provoke antimicrobial activities of CeONPs against human pathogenic bacteria and plant infecting fungi. The results show that CeONPs possessed good antimicrobial properties and are effective to use for pharmaceutical applications and as a food preservative because of low toxicity, organic coating, and acceptable antimicrobial properties. This study showed a rapid and well-organized method to prepare stable phytochemical-coated CeONPs with three different plants , , and with remarkable antibacterial and antifungal characteristics.
PubMed: 38585053
DOI: 10.1021/acsomega.4c00236 -
The Science of the Total Environment Jun 2024Antibiotic resistance genes (ARGs) are a major threat to human and environmental health. This study investigated the occurrence and distribution of ARGs in Lake...
Antibiotic resistance genes (ARGs) are a major threat to human and environmental health. This study investigated the occurrence and distribution of ARGs in Lake Cajititlán, a hypereutrophic subtropical lake in Mexico contaminated by anthropogenic sources (urban wastewater and runoff from crop and livestock production). ARGs (a total of 475 genes) were detected in 22 bacterial genera, with Pseudomonas (144 genes), Stenotrophomonas (88 genes), Mycobacterium (54 genes), and Rhodococcus (27 genes) displaying the highest frequencies of ARGs. Among these, Pseudomonas aeruginosa and Stenotrophomonas maltophilia showed the highest number of ARGs. The results revealed a diverse array of ARGs, including resistance to macrolides (11.55 %), aminoglycosides (8.22 %), glycopeptides (6.22 %), tetracyclines (4 %), sulfonamides (4 %), carbapenems (1.11 %), phenicols (0.88 %), fluoroquinolones (0.44 %), and lincosamides (0.22 %). The most frequently observed ARGs were associated with multidrug resistance (63.33 %), with MexF (42 genes), MexW (36 genes), smeD (31 genes), mtrA (25 genes), and KHM-1 (22 genes) being the most common. Lake Cajititlán is a recreational area for swimming, fishing, and boating, while also supporting irrigation for agriculture and potentially acting as a drinking water source for some communities. This raises concerns about the potential for exposure to antibiotic-resistant bacteria through these activities. The presence of ARGs in Lake Cajititlán poses a significant threat to both human and environmental health. Developing strategies to mitigate the risks of antibiotic resistance, including improving wastewater treatment, and promoting strategic antibiotic use and disposal, is crucial. This study represents a significant advancement in the understanding of antibiotic resistance dynamics in a hypereutrophic subtropical lake in a developing country, providing valuable insights for the scientific community and policymakers.
Topics: Lakes; Environmental Monitoring; Drug Resistance, Microbial; Mexico; Anti-Bacterial Agents; Metagenomics; Genes, Bacterial; Drug Resistance, Bacterial; Wastewater; Bacteria; Water Pollutants, Chemical
PubMed: 38583614
DOI: 10.1016/j.scitotenv.2024.172216 -
Environmental Pollution (Barking, Essex... May 2024Cigarette smoke (CS), the main source of indoor air pollution and the primary risk factor for respiratory diseases, contains chemicals that can perturb microbiota...
Cigarette smoke (CS), the main source of indoor air pollution and the primary risk factor for respiratory diseases, contains chemicals that can perturb microbiota through antibiotic effects. Although smoking induces a disturbance of microbiota in the lower respiratory tract, whether and how it contributes to initiation or promotion of emphysema are not well clarified. Here, we demonstrated an aberrant microbiome in lung tissue of patients with smoking-related COPD. We found that Stenotrophomonas maltophilia (S. maltophilia) was expanded in lung tissue of patients with smoking-related COPD. We revealed that S. maltophilia drives PANoptosis in alveolar epithelial cells and represses formation of alveolar organoids through IRF1 (interferon regulatory factor 1). Mechanistically, IRF1 accelerated transcription of ZBP1 (Z-DNA Binding Protein 1) in S. maltophilia-infected alveolar epithelial cells. Elevated ZBP1 served as a component of the PANoptosome, which triggered PANoptosis in these cells. By using of alveolar organoids infected by S. maltophilia, we found that targeting of IRF1 mitigated S. maltophilia-induced injury of these organoids. Moreover, the expansion of S. maltophilia and the expression of IRF1 negatively correlated with the progression of emphysema. Thus, the present study provides insights into the mechanism of lung dysbiosis in smoking-related COPD, and presents a potential target for mitigation of COPD progression.
Topics: Animals; Humans; Alveolar Epithelial Cells; Interferon Regulatory Factor-1; Lung; Microbiota; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Smoking; Stenotrophomonas maltophilia
PubMed: 38582189
DOI: 10.1016/j.envpol.2024.123913 -
BMC Infectious Diseases Apr 2024Bloodstream infections (BSI) are the major cause of morbidity and mortality in children in developing countries. The purpose of the current study was to establish the...
BACKGROUND
Bloodstream infections (BSI) are the major cause of morbidity and mortality in children in developing countries. The purpose of the current study was to establish the antimicrobial susceptibility pattern of bacterial isolates from bloodstream infections at Children's Medical Center Hospital (CMC), Tehran, Iran.
METHODS
We retrospectively recorded all positive blood cultures and antimicrobial susceptibility of all bloodstream isolates among children admitted to CMC, during 5 years. Specimen culture, bacterial identification, and antimicrobial susceptibility testing were performed according to standard laboratory methods.
RESULTS
From 3,179 pathogens isolated from the blood cultures 2,824 bacteria were cultured, with 1,312 cases being identified as Gram-positive bacteria (46%) and 1,512 cases as Gram-negative bacteria (54%). The most common Gram-negative bacteria isolated were as follows: Pseudomonas spp. (n = 266, 17.6%), Klebsiella pneumoniae (n = 242, 16%), Stenotrophomonas maltophilia (n = 204, 13.5%), Enterobacter spp. (n = 164, 10.8%), Escherichia coli (n = 159, 10.5%), Pseudomonas aeruginosa (n = 126, 8.3%), Serratia marcescens (n = 121, 8%), and Acinetobacter baumannii (n = 73, 4.8%). The most common Gram-positive bacteria isolated were coagulase-negative staphylococci (CONS) (n = 697, 53%), Streptococcus spp. (n = 237, 18%), Staphylococcus aureus (n = 202, 15%) and Enterococcus spp. (n = 167, 12.7%). 34% of bacterial strains were isolated from ICUs. The rates of methicillin resistance in S. aureus and CONS were 34% and 91%, respectively. E. coli isolates showed high resistance to cefotaxime (84%). All isolates of K. pneumoniae were susceptible to colistin and 56% were susceptible to imipenem. P. aeruginosa isolates showed high susceptibility to all antibiotics.
CONCLUSIONS
Our findings emphasize the need of clinicians having access to up-to-date bacterial susceptibility data for routinely prescribed drugs. Continuous monitoring of changes in bacterial resistance will aid in the establishment of national priorities for local intervention initiatives in Iran. The increased risk of BSI caused by antibiotic-resistant organisms, emphasizes the significance of implementing appropriate antibiotic prescribing regulations and developing innovative vaccination techniques in Iran.
Topics: Humans; Child; Anti-Bacterial Agents; Iran; Staphylococcus aureus; Escherichia coli; Retrospective Studies; Bacteremia; Drug Resistance, Bacterial; Bacteria; Sepsis; Gram-Negative Bacteria; Gram-Positive Bacteria; Staphylococcus; Pseudomonas aeruginosa; Klebsiella pneumoniae; Staphylococcal Infections; Pseudomonas; Referral and Consultation; Hospitals; Microbial Sensitivity Tests
PubMed: 38565980
DOI: 10.1186/s12879-024-09260-w -
BioRxiv : the Preprint Server For... Mar 2024Supercoiled flagellar filaments function as mechanical propellers within the bacterial flagellum complex, playing a crucial role in motility. Flagellin, the building...
Supercoiled flagellar filaments function as mechanical propellers within the bacterial flagellum complex, playing a crucial role in motility. Flagellin, the building block of the filament, features a conserved inner D0/D1 core domain across different bacterial species. In contrast, approximately half of the flagellins possess additional, highly divergent outer domain(s), suggesting varied functional potential. In this study, we elucidate atomic structures of flagellar filaments from three distinct bacterial species: , , and . Our findings reveal that the flagella from the facultative anaerobic possesses a significantly more negatively charged surface, potentially enabling adhesion to positively charged minerals. Furthermore, we analyzed all AlphaFold predicted structures for annotated bacterial flagellins, categorizing the flagellin outer domains into 682 structural clusters. This classification provides insights into the prevalence and experimental verification of these outer domains. Remarkably, two of the flagellar structures reported herein belong to a previously unexplored cluster, indicating new opportunities on the study of the functional diversity of flagellar outer domains. Our findings underscore the complexity of bacterial flagellins and open up possibilities for future studies into their varied roles beyond motility.
PubMed: 38562817
DOI: 10.1101/2024.03.18.585621 -
Journal of Dentistry Jun 2024To determine and compare the opportunistic respiratory pathogenic index (ORPI) and prevalence of respiratory pathogens between clean and unclean removable prostheses. (Comparative Study)
Comparative Study
OBJECTIVES
To determine and compare the opportunistic respiratory pathogenic index (ORPI) and prevalence of respiratory pathogens between clean and unclean removable prostheses.
METHODS
A cross-sectional study was conducted among 97 removable prosthesis wearers at a teaching dental hospital. Participants' prosthesis hygiene was grouped into clean and unclean. After prosthesis plaque samples were sequenced using the Type IIB Restriction-site Associated DNA Sequencing for Microbiome method, the prevalence was assessed for the presence of respiratory pathogens on each sample. The ORPIs for clean and unclean prostheses were quantified based on the sum of the relative abundance of respiratory pathogenic bacteria in a microbiome using a reference database that contains opportunistic respiratory pathogens and disease-associated information.
RESULTS
A total of 30 opportunistic respiratory pathogens were identified on the removable prostheses. Eighty-one (83.5 %) removable prostheses harboured respiratory pathogenic bacteria. Stenotrophomonas maltophilia (34.0 %), Pseudomonas aeruginosa (27.8 %), and Streptococcus agalactiae (27.8 %) were the top three prevalent respiratory pathogens detected in plaque samples. There was a significantly higher prevalence of respiratory pathogens residing on unclean than clean prostheses (P = 0.046). However, the ORPIs in both groups showed no statistically significant difference (P = 0.516).
CONCLUSIONS
The ORPIs for both clean and unclean prostheses demonstrated a similar abundance of respiratory pathogens. However, the high prevalence of respiratory pathogens residing on unclean prostheses should not be underestimated. Therefore, maintaining good prosthesis hygiene is still important for overall oral and systemic health, even though the direct link between prosthesis cleanliness and reduced abundance of respiratory pathogens has not been established.
CLINICAL SIGNIFICANCE
The association between the prevalence of respiratory pathogens and unclean removable prostheses has been demonstrated and might increase the theoretical risk of respiratory disease development.
Topics: Humans; Cross-Sectional Studies; Female; Male; Aged; Middle Aged; Prevalence; Dental Plaque; Respiratory Tract Infections; Opportunistic Infections; Oral Hygiene; Microbiota; Bacteria; Aged, 80 and over; Prosthesis-Related Infections; Denture, Partial, Removable
PubMed: 38561038
DOI: 10.1016/j.jdent.2024.104968