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Microbiology Spectrum Jul 2024Delayed time to antimicrobial susceptibility results can impact patients' outcomes. Our study evaluated the impact of susceptibility turnaround time (TAT) and inadequate...
Delayed time to antimicrobial susceptibility results can impact patients' outcomes. Our study evaluated the impact of susceptibility turnaround time (TAT) and inadequate empiric antibacterial therapy (IET) in patients with bloodstream infections (BSI) caused by (ENT) species on in-hospital mortality and length of stay (LOS). This retrospective, multicenter investigation which included 29,570 blood ENT-positive admissions across 161 US healthcare facilities evaluated the association between antimicrobial susceptibility testing (AST) TAT, carbapenem susceptibility, and empiric therapy on post-BSI in-hospital mortality and LOS following an ENT BSI event in adult patients. After adjusting for outcomes covariates, post-BSI in-hospital mortality was significantly higher for patients in the IET vs adequate empiric therapy (AET) group [odds ratio (OR): 1.61 (95% CI: 1.32, 1.98); < 0.0001], and when AST TAT was >63 h [OR:1.48 (95% CI: 1.16, 1.90); = 0.0017]. Patients with carbapenem non-susceptible (carb-NS) ENT BSI had significantly higher LOS (16.6 days, 95% CI: 15.6, 17.8) compared to carbapenem susceptible (carb-S, 12.2 days, 95% CI: 11.8, 12.6), ( < 0.0001). Extended AST TAT was significantly associated with longer LOS for TAT of 57-65 h and >65 h ( = 0.005 and < 0.0001, respectively) compared to TAT ≤42 h (reference). Inadequate empiric therapy (IET), carb-NS, and delayed AST TAT are significantly associated with adverse hospital outcomes in ENT BSI. Workflows that accelerate AST TAT for ENT BSIs and facilitate timely and adequate therapy may reduce post-BSI in-hospital mortality rate and LOS.IMPORTANCEFor patients diagnosed with bloodstream infections (BSI) caused by (ENT), delayed time to antimicrobial susceptibility (AST) results can significantly impact in-hospital mortality and hospital length of stay. However, this relationship between time elapsed from blood culture collection to AST results has only been assessed, to date, in a limited number of publications. Our study focuses on this important gap using retrospective data from 29,570 blood ENT-positive admissions across 161 healthcare facilities in the US as we believe that a thorough understanding of the dynamic between AST turnaround time, adequacy of empiric therapy, post-BSI event mortality, and hospital length of stay will help guide effective clinical management and optimize outcomes of patients with ENT infections.
PubMed: 38953323
DOI: 10.1128/spectrum.00402-24 -
MSystems Jul 2024The erythromycin resistance RNA methyltransferase () confers cross-resistance to all therapeutically important macrolides, lincosamides, and streptogramins (MLS...
UNLABELLED
The erythromycin resistance RNA methyltransferase () confers cross-resistance to all therapeutically important macrolides, lincosamides, and streptogramins (MLS phenotype). The expression of is often induced by the macrolide-mediated ribosome stalling in the upstream co-transcribed leader sequence, thereby triggering a conformational switch of the intergenic RNA hairpins to allow the translational initiation of . We investigated the evolutionary emergence of the upstream regulatory elements and the impact of allelic variation on erm expression and the MLS phenotype. Through systematic profiling of the upstream regulatory sequences across all known operons, we observed that specific subfamilies, such as and , have independently evolved distinct configurations of small upstream ORFs and palindromic repeats. A population-wide genomic analysis of the upstream regions revealed substantial non-random allelic variation at numerous positions. Utilizing machine learning-based classification coupled with RNA structure modeling, we found that many alleles cooperatively influence the stability of alternative RNA hairpin structures formed by the palindromic repeats, which, in turn, affects the inducibility of expression and MLS phenotypes. Subsequent experimental validation of 11 randomly selected variants demonstrated an impressive 91% accuracy in predicting MLS phenotypes. Furthermore, we uncovered a mixed distribution of MLS-sensitive and MLS-resistant loci within the evolutionary tree, indicating repeated and independent evolution of MLS resistance. Taken together, this study not only elucidates the evolutionary processes driving the emergence and development of MLS resistance but also highlights the potential of using non-coding genomic allele data to predict antibiotic resistance phenotypes.
IMPORTANCE
Antibiotic resistance (AR) poses a global health threat as the efficacy of available antibiotics has rapidly eroded due to the widespread transmission of AR genes. Using Erm-dependent MLS resistance as a model, this study highlights the significance of non-coding genomic allelic variations. Through a comprehensive analysis of upstream regulatory elements within the family, we elucidated the evolutionary emergence and development of AR mechanisms. Leveraging population-wide machine learning (ML)-based genomic analysis, we transformed substantial non-random allelic variations into discernible clusters of elements, enabling precise prediction of MLS phenotypes from non-coding regions. These findings offer deeper insight into AR evolution and demonstrate the potential of harnessing non-coding genomic allele data for accurately predicting AR phenotypes.
PubMed: 38953319
DOI: 10.1128/msystems.00430-24 -
Cureus May 2024Introduction Pulmonary tuberculosis (TB) remains a global health concern, exacerbated by the emergence of extensively drug-resistant (XDR) strains of . This study...
Introduction Pulmonary tuberculosis (TB) remains a global health concern, exacerbated by the emergence of extensively drug-resistant (XDR) strains of . This study employs advanced molecular techniques, specifically polymerase chain reaction (PCR) profiling, to comprehensively characterize the genetic landscape of XDR pathogenic bacteria in patients diagnosed with pulmonary TB. The objective of the study is to elucidate the genes that are associated with drug resistance in pulmonary TB strains through the application of PCR and analyze specific genetic loci that contribute to the development of resistance against multiple drugs. Materials and methods A total of 116 clinical samples suspected of TB were collected from the tertiary healthcare setting of Saveetha Medical College and Hospitals for the identification of MTB, which includes sputum (n = 35), nasal swabs (n = 17), blood (n = 44), and bronchoalveolar lavage (BAL) (n = 20). The collected specimens were processed and subjected to DNA extraction. As per the protocol, reconstitution of the DNA pellet was carried out. The reconstituted DNA was stored at -20 °C for the PCR assay. From the obtained positive sample specimens, XDR pulmonary TB specimens were focused on the targeted genes, specifically the gene for rifampicin resistance, , and gene for thepromoter region for isoniazid resistance. Results Out of a total of 116 samples obtained, 53 tested positive for pulmonary TB, indicative of a mycobacterial infection. Among these positive cases, 43 patients underwent treatment at a tertiary healthcare facility. Subsequently, a PCR assay was performed with the extracted DNA for the target genes , , and . Specifically, 22 sputum samples exhibited gene expression for , , and , while nine nasal swabs showed expression of the and genes. Additionally, gene expression was detected in seven blood specimens, and both and genes were expressed in five BAL samples. Conclusion The swift diagnosis and efficient treatment of XDR-TB can be facilitated by employing advanced and rapid molecular tests and oral medication regimens. Utilizing both newly developed and repurposed anti-TB drugs like pretomanid, bedaquiline, linezolid, and ethionamide. Adhering to these current recommendations holds promise for managing XDR-TB effectively. Nevertheless, it is significant to conduct well-designed clinical trials and studies to further evaluate the efficacy of new agents and shorter treatment regimens, thus ensuring continuous improvement in the management of this challenging condition.
PubMed: 38953074
DOI: 10.7759/cureus.61424 -
Frontiers in Cellular and Infection... 2024
Review
Topics: Humans; Staphylococcal Infections; Endopeptidases; Drug Resistance, Multiple, Bacterial; Bacteriophages; Phage Therapy; Anti-Bacterial Agents; Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus
PubMed: 38953006
DOI: 10.3389/fcimb.2024.1397935 -
PeerJ 2024Agricultural soils contaminated with heavy metals poison crops and disturb the normal functioning of rhizosphere microbial communities. Different crops and rhizosphere...
Agricultural soils contaminated with heavy metals poison crops and disturb the normal functioning of rhizosphere microbial communities. Different crops and rhizosphere microbial communities exhibit different heavy metal resistance mechanisms. Here, indoor pot studies were used to assess the mechanisms of grain and soil rhizosphere microbial communities on chromium (Cr) stress. Millet grain variety 'Jingu 21' () and soil samples were collected prior to control (CK), 6 hours after (Cr_6h), and 6 days following (Cr_6d) Cr stress. Transcriptomic analysis, high-throughput sequencing and quantitative polymerase chain reaction (qPCR) were used for sample determination and data analysis. Cr stress inhibited the expression of genes related to cell division, and photosynthesis in grain plants while stimulating the expression of genes related to DNA replication and repair, in addition to plant defense systems resist Cr stress. In response to chromium stress, rhizosphere soil bacterial and fungal community compositions and diversity changed significantly ( < 0.05). Both bacterial and fungal co-occurrence networks primarily comprised positively correlated edges that would serve to increase community stability. However, bacterial community networks were larger than fungal community networks and were more tightly connected and less modular than fungal networks. The abundances of C/N functional genes exhibited increasing trends with increased Cr exposure. Overall, these results suggest that Cr stress primarily prevented cereal seedlings from completing photosynthesis, cell division, and proliferation while simultaneously triggering plant defense mechanisms to resist the toxic effects of Cr. Soil bacterial and fungal populations exhibited diverse response traits, community-assembly mechanisms, and increased expression of functional genes related to carbon and nitrogen cycling, all of which are likely related to microbial survival during Cr stress. This study provides new insights into resistance mechanisms, microbial community structures, and mechanisms of C/N functional genes responses in cereal plants to heavy metal contaminated agricultural soils. Portions of this text were previously published as part of a preprint (https://www.researchsquare.com/article/rs-2891904/v1).
Topics: Soil Microbiology; Chromium; Rhizosphere; Soil Pollutants; Edible Grain; Stress, Physiological; Fungi; Microbiota; Bacteria
PubMed: 38952992
DOI: 10.7717/peerj.17461 -
BioRxiv : the Preprint Server For... May 2024The microbiota can promote host health by inhibiting pathogen colonization, yet how host-resident fungi, or the mycobiota, contribute to this process remains unclear....
UNLABELLED
The microbiota can promote host health by inhibiting pathogen colonization, yet how host-resident fungi, or the mycobiota, contribute to this process remains unclear. The human skin mycobiota is uniquely stable compared to other body sites and dominated by yeasts of the genus . We observe that colonization of human skin by significantly reduces subsequent colonization by the prominent bacterial pathogen . secreted products possess potent bactericidal activity against and are sufficient to impair skin colonization. This bactericidal activity requires an acidic environment and is exacerbated by free fatty acids, demonstrating a unique synergy with host-derived epidermal defenses. Leveraging experimental evolution to pinpoint mechanisms of adaptation in response to the skin mycobiota, we identified multiple mutations in the stringent response regulator Rel that promote survival against . Similar Rel alleles have been reported in clinical isolates, and natural Rel variants are sufficient for tolerance to antagonism. Partial stringent response activation underlies tolerance to clinical antibiotics, with both laboratory-evolved and natural Rel variants conferring multidrug tolerance. These findings demonstrate the ability of the mycobiota to mediate pathogen colonization resistance, identify new mechanisms of bacterial adaptation in response to fungal antagonism, and reveal the potential for microbiota-driven evolution to shape pathogen antibiotic susceptibility.
HIGHLIGHTS
- reduces colonization of human skin by - Bactericidal activity of is exacerbated by features of the skin niche - Rel variants are sufficient for tolerance to antagonism - Evolved tolerance to yeast antagonism coincides with multidrug tolerance.
PubMed: 38952794
DOI: 10.1101/2024.05.03.592489 -
Iranian Journal of Medical Sciences Jun 2024Spontaneous bacterial peritonitis (SBP) is a fatal complication of ascites fluid infection. The causes of SBP in children differ from those in adults, and these bacteria...
Clinical Findings, Bacterial Agents, and Antibiotic Resistance in Children with Spontaneous Peritonitis in Southern Iran: An Academic Tertiary Referral Center's Experience.
BACKGROUND
Spontaneous bacterial peritonitis (SBP) is a fatal complication of ascites fluid infection. The causes of SBP in children differ from those in adults, and these bacteria are frequently resistant to antibiotics. Therefore, this study investigated the clinical findings, bacterial etiology, and antimicrobial resistance in children with SBP.
METHODS
This study was conducted on all new pediatric ascites patients, who were admitted to the Department of Pediatric Gastroenterology, Namazi Hospital, affiliated with Shiraz University of Medical Sciences (Shiraz, Iran) from 2021 to 2022. Required data such as demographic information, and clinical information such as complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Gram staining, blood culture by Automated Blood Culture System (BACTEC), and antibiogram of ascites fluids by disc diffusion method were all collected. Finally, the data were statistically analyzed using SPSS Software (version 26). Besides, the test, Fisher's exact, Mann-Whitney, and Chi square tests were used for data analysis. In all tests, P≤0.05 was considered statistically significant.
RESULTS
The present study examined 62 children with ascites of which 18 (29%) had SBP. The median (IQR) age was 2.5 (8.1) years. Thirty-four (54.8%) of the participants were girls. Abdominal pain was the most common clinical manifestation in patients (54%), and there was a significant association between abdominal pain and SBP (P=0.02). In 12 positive ascites fluid cultures, coagulase-negative staphylococci had the highest frequency (25%), followed by (16.7%). Third-generation cephalosporins had a 25% sensitivity in the total positive cultures. This sensitivity was 33.3% for Gram-negative cultures and 16.6% for Gram-positive cultures.
CONCLUSION
Although third-generation cephalosporins are recommended as the primary antibiotic for the empirical treatment of SBP, the present study found high bacterial resistance. Finally, empirical therapy should be tailored to each region's bacterial resistance features.
Topics: Humans; Peritonitis; Child; Female; Male; Iran; Child, Preschool; Anti-Bacterial Agents; Tertiary Care Centers; Infant; Adolescent; Drug Resistance, Bacterial; Ascites; Bacterial Infections; Microbial Sensitivity Tests
PubMed: 38952643
DOI: 10.30476/ijms.2023.98747.3082 -
Cureus Jun 2024Background Periodontal disease poses a significant oral health challenge, involving inflammatory conditions impacting tooth-supporting structures. Treponema denticola, a...
Background Periodontal disease poses a significant oral health challenge, involving inflammatory conditions impacting tooth-supporting structures. Treponema denticola, a "red complex" organism, plays a crucial role in periodontal pathogenesis, forming biofilms in subgingival environments and contributing to dysbiosis. Antimicrobial therapy is pivotal in managing periodontal disease, requiring a nuanced understanding of susceptibility patterns exhibited by key pathogens like T. denticola Aims and objectives This study aims to investigate the antimicrobial susceptibility and resistance profiles of Treponema denticola, a prominent bacterium in periodontal disease, by examining its responses to various antimicrobial agents commonly used in periodontal therapy. Methodology Plaque samples were meticulously collected from individuals diagnosed with periodontal disease to ensure a diverse representation of the oral microbiome. All the samples were cultured, and red complex bacteria were isolated under anaerobic culture. Treponema denticola isolates were cultured from these samples under anaerobic conditions, and molecular techniques were employed for species identification. A comprehensive panel of antimicrobial agents was selected to assess the response of Treponema denticola. In vitro antimicrobial susceptibility testing (AST) was conducted using the antimicrobial gradient method, employing a hybrid approach combining elements of disk-diffusion and dilution methods. Results Treponema denticola had exhibited resistance to metronidazole, a commonly used antibiotic effective against anaerobic bacteria, emphasizing limitations in its applicability. However, the bacterium displayed sensitivity to tetracycline, imipenem, cefoperazone, chloramphenicol, clindamycin, and moxifloxacin, offering diverse therapeutic options. The antimicrobial gradient strip test provided detailed minimum inhibitory concentration (MIC) values, contributing to a nuanced understanding of susceptibility and resistance patterns. Conclusion This study significantly advances our understanding of Treponema denticola's antimicrobial susceptibility and resistance profiles in the context of periodontal disease. The findings underscore the importance of tailored treatment strategies and contribute to broader efforts in antimicrobial stewardship, aligning with global initiatives to combat antibiotic resistance. This research lays the foundation for more effective and personalized approaches to periodontal care, emphasizing the intricate microbial dynamics associated with periodontal health and disease.
PubMed: 38952590
DOI: 10.7759/cureus.61497 -
Cureus Jun 2024Microbial detection and antimicrobial resistance (AMR) surveillance are critical components of public health efforts to combat infectious diseases and preserve the... (Review)
Review
Microbial detection and antimicrobial resistance (AMR) surveillance are critical components of public health efforts to combat infectious diseases and preserve the efficacy of antimicrobial agents. While foundational in microbial identification, traditional cultural methods are often laborious, time-consuming, and limited in their ability to detect AMR markers. In response to these challenges, innovative paradigms have emerged, leveraging advances in molecular biology, genomics, proteomics, nanotechnology, and bioinformatics. This comprehensive review provides an overview of innovative approaches beyond traditional cultural methods for microbial detection and AMR surveillance. Molecular-based techniques such as polymerase chain reaction (PCR) and next-generation sequencing (NGS) offer enhanced sensitivity and specificity, enabling the rapid identification of microbial pathogens and AMR determinants. Mass spectrometry-based methods provide rapid and accurate detection of microbial biomarkers, including matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and biosensor technologies. Nanotechnology approaches, such as nanoparticle-based assays and nanopore sequencing, offer novel platforms for sensitive and label-free detection of pathogens and AMR markers. Embracing these innovative paradigms holds immense promise for improving disease diagnosis, antibiotic stewardship, and AMR containment efforts. However, challenges such as cost, standardization, and integration with existing healthcare systems must be addressed to realize the full potential of these technologies. By fostering interdisciplinary collaboration and innovation, we can strengthen our ability to detect, monitor, and combat AMR, safeguarding public health for generations.
PubMed: 38952583
DOI: 10.7759/cureus.61476 -
Pakistan Journal of Medical Sciences Jul 2024To determine the antimicrobial activity of silver nano-particles(AgNPs) with tetracycline and ampicillin against multi-drug resistance (MDR) and extensively-drug...
OBJECTIVES
To determine the antimicrobial activity of silver nano-particles(AgNPs) with tetracycline and ampicillin against multi-drug resistance (MDR) and extensively-drug resistance (XDR) .
METHODS
Cross sectional non-probability purposive study was conducted from September, 2021 to May, 2022 at Microbiology department PNS Shifa, Hospital Karachi. Blood cultures of patients suspicious of typhoid fever were collected and incubated in automated Bact/Alert system. Positive cultures were identified on blood and MacConkey and processed by API-10S, confirmed by serotyping (O9 antisera) (SSI Diagnostica's . Antibiotic resistance was done by Kirby-Bauer disk diffusion (Sigma and Rich). MDR and XDR isolates were preserved in Brain Heart Infusion in a volume of 2ml in screw capped bottles at -70°C. Antimicrobial powders (ampicillin and tetracycline (Alfa Aesar) weighed by an electrical weighing balance (OHAUS) to take 1mg of antimicrobial drug. Absorbance spectra of serial concentrations of antibiotics (UV-Vis spectrophotometer (Mole-Qule-) AgNPs (10nm) (nanocomposix) + Antibiotic in (1:1 volume ratio). Conjugation of silver nanoparticles with tetracycline and ampicillin was done by FTIR (thermos scientificThermos ScientificNicolet 50).
RESULTS
Out of 77 isolates, 54 were resistant to ceftriaxone (XDR) and 23 sensitive to ceftriaxone (MDR). All isolates were susceptible to azithromycin and meropenem. Comparison of zone of inhibitions of ampicillin and Amp-AgNPsas and tetracycline with Tet-AgNPs was done. Minimal inhibitory concentration was also done to determine antimicrobial activity.
CONCLUSION
Significant synergistic inhibitory effects against isolates were obtained by combination of tetracycline with silver nano-particles even at low concentration.
PubMed: 38952512
DOI: 10.12669/pjms.40.6.7900