scholarly journals Immunosuppression broadens evolutionary pathways to treatment failure during Acinetobacter baumannii pneumonia

2021 ◽  
Author(s):  
Wenwen Huo ◽  
Lindsay M Busch ◽  
Efrat Hamami ◽  
Juan Hernandez-Bird ◽  
Christopher W Marshall ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Treatment Failure ◽  
Acinetobacter Baumannii ◽  
Antibiotic Treatment ◽  
Immunocompromised Host ◽  
Fluoroquinolone Resistance ◽  
Unexpected Result ◽  
Human Pathogens ◽  
Antibiotic Failure ◽  
High Level

Acinetobacter baumannii is increasingly refractory to antibiotic treatment in healthcare settings. As is true of most human pathogens, the genetic path to antimicrobial resistance (AMR) and the role that the immune system plays in modulating AMR during disease are poorly understood. Here we reproduced several routes to fluoroquinolone resistance, performing evolution experiments using sequential lung infections in mice that are replete or depleted of neutrophils, providing two key insights into the evolution of drug resistance. First, neutropenic hosts were demonstrated to act as reservoirs for the accumulation of drug resistance. Selection for variants with altered drug sensitivity profiles arose readily in the absence of neutrophils, while immunocompetent animals restricted the appearance of these variants. Secondly, antibiotic treatment failure was shown to occur without clinically defined resistance, an unexpected result that provides a model for how antibiotic failure occurs clinically in the absence of AMR. The genetic mechanism underlying both these results is initiated by mutations activating the drug egress pump regulator AdeL, which drives persistence in the presence of the antibiotic. Therefore, antibiotic persistence mutations are demonstrated to present a two-pronged risk during disease, causing drug treatment failure in the immunocompromised host while simultaneously increasing the likelihood of high-level AMR acquisition.

scholarly journals Antibiotic Treatment Failure and Associated Outcomes Among Adult Patients With Community-Acquired Pneumonia in the Outpatient Setting: A Real-world US Insurance Claims Database Study

2020 ◽  
Vol 7 (3) ◽  
Author(s):  
Glenn Tillotson ◽  
Thomas Lodise ◽  
Peter Classi ◽  
Donna Mildvan ◽  
James A McKinnell
Keyword(s):  
Health Care ◽  
Treatment Failure ◽  
Antibiotic Treatment ◽  
Health Care Costs ◽  
Outpatient Setting ◽  
Community Acquired Pneumonia ◽  
Failure Group ◽  
Antibiotic Failure ◽  
Care Costs ◽  
Experienced Treatment

Abstract Background Antibiotic treatment failure is common among patients with community-acquired pneumonia (CAP) who are managed in the outpatient setting and is associated with higher mortality and increased health care costs. This study’s objectives were to quantify the occurrence of antibiotic treatment failure (ATF) and to evaluate clinical and economic outcomes between CAP patients who experienced ATF relative to those who did not. Methods Retrospective analysis of the MarketScan Commercial & Medicare Supplemental Databases was performed, identifying patients ≥18 years old, with a pneumonia diagnosis in the outpatient setting, and who received a fluoroquinolone, macrolides, beta-lactam, or tetracycline. ATF was defined as any of the following events within 30 days of initial antibiotic: antibiotic refill, antibiotic switch, emergency room visit, or hospitalization. Outcomes included 30-day all-cause mortality and CAP-related health care costs. Results During the study period, 251 947 unique patients met inclusion criteria. The mean age was 52.2 years, and 47.7% were male. The majority of patients received a fluoroquinolone (44.4%) or macrolide (43.6%). Overall, 22.1% were classified as ATFs. Among 18–64-year-old patients, 21.2% experienced treatment failure, compared with 25.7% in those >65 years old. All-cause mortality was greater in the antibiotic failure group relative to the non–antibiotic failure group (18.1% vs 4.6%, respectively), and the differences in 30-day mortality between antibiotic failure groups increased as a function of age. Mean 30-day CAP-related health care costs were also higher in the patients who experienced treatment failure relative to those who did not ($2140 vs $54, respectively). Conclusions Treatment failure and poor outcomes from outpatient CAP are common with current guideline-concordant CAP therapies. Improvements in clinical management programs and therapeutic options are needed.

scholarly journals High level of treatment failure and drug resistance to first-line antiretroviral therapies among HIV-infected children receiving decentralized care in Senegal

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Abdoul-Magib Cissé ◽  
Gabrièle Laborde-Balen ◽  
Khady Kébé-Fall ◽  
Aboubacry Dramé ◽  
Halimatou Diop ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Treatment Failure ◽  
First Line ◽  
Antiretroviral Therapies ◽  
High Level ◽  
Decentralized Care

scholarly journals DNA Gyrase and Topoisomerase IV Mutations Associated with Fluoroquinolone Resistance in Proteus mirabilis

2002 ◽  
Vol 46 (8) ◽  
pp. 2582-2587 ◽  
Author(s):  
L. M. Weigel ◽  
G. J. Anderson ◽  
F. C. Tenover
Keyword(s):  
Proteus Mirabilis ◽  
Bacterial Species ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Unexpected Result ◽  
Topoisomerase Iv ◽  
Frequent Event ◽  
Nucleotide Insertion ◽  
High Level ◽  
Susceptibility Profiles

ABSTRACT Mutations associated with fluoroquinolone resistance in clinical isolates of Proteus mirabilis were determined by genetic analysis of the quinolone resistance-determining region (QRDR) of gyrA, gyrB, parC, and parE. This study included the P. mirabilis type strain ATCC 29906 and 29 clinical isolates with reduced susceptibility (MIC, 0.5 to 2 μg/ml) or resistance (MIC, ≥4 μg/ml) to ciprofloxacin. Susceptibility profiles for ciprofloxacin, clinafloxacin, gatifloxacin, gemifloxacin, levofloxacin, moxifloxacin, and trovafloxacin were correlated with amino acid changes in the QRDRs. Decreased susceptibility and resistance were associated with double mutations involving both gyrA (S83R or -I) and parC (S80R or -I). Among these double mutants, MICs of ciprofloxacin varied from 1 to 16 μg/ml, indicating that additional factors, such as drug efflux or porin changes, also contribute to the level of resistance. For ParE, a single conservative change of V364I was detected in seven strains. An unexpected result was the association of gyrB mutations with high-level resistance to fluoroquinolones in 12 of 20 ciprofloxacin-resistant isolates. Changes in GyrB included S464Y (six isolates), S464F (three isolates), and E466D (two isolates). A three-nucleotide insertion, resulting in an additional lysine residue between K455 and A456, was detected in gyrB of one strain. Unlike any other bacterial species analyzed to date, mutation of gyrB appears to be a frequent event in the acquisition of fluoroquinolone resistance among clinical isolates of P. mirabilis.

scholarly journals Digital Insights Into Nucleotide Metabolism and Antibiotic Treatment Failure

2021 ◽  
Vol 3 ◽  
Author(s):  
Allison J. Lopatkin ◽  
Jason H. Yang
Keyword(s):  
Treatment Failure ◽  
Antibiotic Treatment ◽  
Molecular Mechanisms ◽  
Failure Mechanisms ◽  
Nucleotide Metabolism ◽  
Bacterial Physiology ◽  
Antibiotic Drug ◽  
Antibiotic Failure ◽  
Human Infections ◽  
Antibiotic Efficacy

Nucleotide metabolism plays a central role in bacterial physiology, producing the nucleic acids necessary for DNA replication and RNA transcription. Recent studies demonstrate that nucleotide metabolism also proactively contributes to antibiotic-induced lethality in bacterial pathogens and that disruptions to nucleotide metabolism contributes to antibiotic treatment failure in the clinic. As antimicrobial resistance continues to grow unchecked, new approaches are needed to study the molecular mechanisms responsible for antibiotic efficacy. Here we review emerging technologies poised to transform understanding into why antibiotics may fail in the clinic. We discuss how these technologies led to the discovery that nucleotide metabolism regulates antibiotic drug responses and why these are relevant to human infections. We highlight opportunities for how studies into nucleotide metabolism may enhance understanding of antibiotic failure mechanisms.

scholarly journals Fluoroquinolone resistance conferred by gyrA, parC mutations, and AbaQ efflux pump among Acinetobacter baumannii clinical isolates causing ventilator-associated pneumonia

2019 ◽  
pp. 1-5 ◽  
Author(s):  
Nancy M. Attia ◽  
Amira ElBaradei
Keyword(s):  
Acinetobacter Baumannii ◽  
Efflux Pump ◽  
Quinolone Resistance ◽  
Fluoroquinolone Resistance ◽  
Ventilator Associated Pneumonia ◽  
Drug Resistant ◽  
The Novel ◽  
New Mutation ◽  
Extensively Drug Resistant ◽  
High Level

Acinetobacter baumannii has emerged as an important nosocomial pathogen due to its ability to survive in hospital settings and its antimicrobial resistance. It is one of the key pathogens in ventilator-associated pneumonia (VAP). The aim of this study was to characterize the mechanisms of quinolone resistance among A. baumannii isolates causing VAP and to investigate the presence of the novel abaQ gene among them. Quinolone-resistant A. baumannii isolates causing VAP were collected over a period of 4 months. Mutations within gyrA and parC were analyzed and the presence of qnrA, qnrB, qnrS, and abaQ was investigated genotypically. Twenty-one A. baumannii isolates were collected, most of them (76.2%) were extensively drug-resistant (XDR) and only one isolate (4.8%) was pandrug-resistant (PDR). All isolates showed high level of resistance to ciprofloxacin, while qnrA, qnrB and qnrS were absent among our isolates. This is the first report of A. baumannii isolates co-harboring Ser81Leu in gyrA and Ser84Leu in parC together with the novel abaQ gene. Interestingly, a new mutation in gyrA quinolone resistance-determining region Arg89Cys was detected among two of our isolates. The emergence of XDR and PDR isolates among A. baumannii causing VAP is an alarming threat.

scholarly journals Multi-drug resistance profiles and the genetic features of Acinetobacter baumannii isolates from Bolivia

2013 ◽  
Vol 7 (04) ◽  
pp. 323-328 ◽  
Author(s):  
Bruno Silvester Lopes ◽  
Lucia Gallego ◽  
Sebastian Giles Becket Amyes
Keyword(s):  
Drug Resistance ◽  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Efflux Pump ◽  
Fluoroquinolone Resistance ◽  
Multi Drug Resistance ◽  
Resistance Mutations ◽  
Aminoglycoside Resistance ◽  
Over Expression ◽  
Hospitalised Patients

Introduction: Acinetobacter baumannii is opportunistic in debilitated hospitalised patients. Because information from some South American countries was previously lacking, this study examined the emergence of multi-resistant A. baumannii in three hospitals in Cochabamba, Bolivia, from 2008 to 2009. Methodology: Multiplex PCR was used to identify the main resistance genes in 15 multi-resistant A. baumannii isolates. RT-PCR was used to measure gene expression. The genetic environment of these genes was also analysed by PCR amplification and sequencing. Minimum inhibitory concentrations were determined for key antibiotics and some were determined in the presence of an efflux pump inhibitor, 1-(1-napthylmethyl) piperazine. Results: Fourteen strains were found to be multi-resistant. Each strain was found to have the blaOXA-58 gene with the ISAba3-like element upstream, responsible for over-expression of the latter and subsequent carbapenem resistance. Similarly, ISAba1, upstream of the blaADC gene caused over-expression of the latter and cephalosporin resistance; mutations in the gyrA(Ser83 to Leu) and parC (Ser-80 to Phe) genes were commensurate with fluoroquinolone resistance. In addition, the adeA, adeB efflux genes were over-expressed. All 15 isolates were positive for at least two aminoglycoside resistance genes. Conclusion: This is one of the first reports analyzing the multi-drug resistance profile of A. baumannii strains isolated in Bolivia and shows that the over-expression of theblaOXA-58, blaADC and efflux genes together with aminoglycoside modifying enzymes and mutations in DNA topoisomerases are responsible for the multi-resistance of the bacteria and the subsequent difficulty in treating infections caused by them.

Role of an ABC Importer in Mycobacterial Drug Resistance

1999 ◽  
Vol 19 (4) ◽  
pp. 293-300 ◽  
Author(s):  
Pradip K. Chakraborti ◽  
Kamlesh Bhatt ◽  
Sanjiban K. Banerjee ◽  
Parimal Misra
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Smegmatis ◽  
Phosphate Transport ◽  
Fluoroquinolone Resistance ◽  
High Level

Phosphate specific transporter (Pst) in bacteria is involved in phosphate transport. Pst is a multisubunit system which belongs to the ABC family of transporters. The import function of this transporter is known to be operative at media phosphate concentrations below the millimolar range. However, we found amplification of this transporter in a laboratory generated ciprofloxacin resistant Mycobacterium smegmatis colony (CIPr) which was grown in a condition when phosphate scavenging function of this operon was inoperative. Our results therefore argue the role of this ABC importer in conferring high level of fluoroquinolone resistance in CIPr.

The gut microbiota resistome provides development of drug resistance in causative agents of human infectious diseases

2017 ◽  
pp. 20-32 ◽  
Author(s):  
Е.Н. Ильина ◽  
Е.И. Олехнович ◽  
А.В. Павленко
Keyword(s):  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Integrated Approach ◽  
Modern Medicine ◽  
Pathogenic Microorganisms ◽  
Human Pathogens ◽  
Potential Source ◽  
Causative Agents ◽  
Bacterial Genes

С течением времени подходы к изучению резистентности к антибиотикам трансформировались от сосредоточения на выделенных в виде чистой культуры патогенных микроорганизмах к исследованию резистентности на уровне микробных сообществ, составляющих биотопы человека и окружающей среды. По мере того, как продвигается изучение устойчивости к антибиотикам, возникает необходимость использования комплексного подхода для улучшения информирования мирового сообщества о наблюдаемых тенденциях в этой области. Все более очевидным становится то, что, хотя не все гены резистентности могут географически и филогенетически распространяться, угроза, которую они представляют, действительно серьезная и требует комплексных междисциплинарных исследований. В настоящее время резистентность к антибиотикам среди патогенов человека стала основной угрозой в современной медицине, и существует значительный интерес к определению ниши, в которых бактерии могут получить гены антибиотикорезистентности, и механизмов их передачи. В данном обзоре мы рассматриваем проблемы, возникшие на фоне широкого использования человечеством антибактериальных препаратов, в свете формирования микрофлорой кишечника резервуара генов резистентности. Over the time, studies of antibiotic resistance have transformed from focusing on pathogenic microorganisms isolated as a pure culture to analysis of resistance at the level of microbial communities that constitute human and environmental biotopes. Advancing studies of antibiotic resistance require an integrated approach to enhance availability of information about observed tendencies in this field to the global community. It becomes increasingly obvious that, even though not all resistance genes can geographically and phylogenetically spread, the threat they pose is indeed serious and requires complex interdisciplinary research. Currently, the antibiotic resistance of human pathogens has become a challenge to modern medicine, which is now focusing on determining a potential source for bacterial genes of drug resistance and mechanisms for the gene transmission. In this review, we discussed problems generated by the widespread use of antibacterial drugs in the light of forming a reservoir of resistance genes by gut microflora.

In Vitro Effect of Chlorquine and Picroliv on Plasmodium Berghei Induced Alterations in the Activity of Adenosine Triphosphatase, Aryl Hyrocarbon Hydroxylase Enzymes and Malondialdehyde in spleen Explant Culture

2020 ◽  
Vol 20 ◽  
Author(s):  
Anchal Trivedi ◽  
Aparna Misra ◽  
Esha Sarkar ◽  
Anil K. Balapure
Keyword(s):  
Drug Resistance ◽  
Plasmodium Berghei ◽  
Adenosine Triphosphatase ◽  
Explant Culture ◽  
Need To Evaluate ◽  
Mda Content ◽  
High Level ◽  
Vitro Effect ◽  
Positive Effect

Background: In recent years, great progress has been made in reducing the high level of malaria suffering worldwide. There is a great need to evaluate drug resistance reversers and consider new medicines against malaria. There are many approaches to the development of antimalarial drugs. Specific concerns must be taken in to account in these approaches, in particular there requirement for very in expensive and simple use of new therapies and the need to limit drug discovery expenses. Important ongoing efforts are the optimisation of treatment with available medications, including the use of combination therapy. The production of analogs of known agents and the identification of natural products, the use of compounds originally developed against other diseases, the assessment of overcoming drug resistance and the consideration of new therapeutic targets. Liver and spleen are the important organs which are directly associated with malarial complications. Aim: An analysis the Activity of Adenosine Triphosphatase, Aryl Hyrocarbon Hydroxylase Enzymes and Malondialdehyde in spleen Explant Culture. Objective: To determine in-Vitro Effect of Chlorquine and Picroliv on Plasmodium Berghei Induced Alterations in the Activity of Adenosine Triphosphatase, Aryl Hyrocarbon Hydroxylase Enzymes and Malondialdehyde in spleen Explant Culture. Material and method: 1-Histological preparation of spleen explants for paraplast embedding 2-Biochemicalstudies (Enzymes (Atpase, ALP&GST) and the level of protein, Malondialdehyde (MDA). Result: Splenomegalyis one of the three main diagnostic parameters of malaria infection besides fever and anaemia. Many enzymes present in the liver and spleen may also be altered or liberated under different pathological conditions. Enzymes (ATPase, ALP&GST) and the level of protein, Malondialdehyde (MDA) content was found to increase in the liver and spleen explants during malarial infection. In the liver and spleen derived from parasitized CQ treated animals, the activity of all the above enzymes (ATPase, ALP&GST) and the level of protein & MDA of liver/spleen reversed towards the normal for all the 4or3 days of incubations. Picroliv efficacy decreased with the increment of parasitaemia and at 60%parasitaemia. Conclusion: Alkalinephosphatase (ALP) was found to increase with increasing parasitaemia. After the addition of Picroliv to the medium, a decrement in the activity was observed up to day 4 of culture.A similar positive effect of Picroliv was observed on the ATPase and ALP activity of spleen explants.DNA and protein contents also increased in the parasitized liver cultured in the presence of picroliv.On the contrary, in the spleen explants DNA, protein and MDA content were found to decrease after Picroliv supplementation to the culture medium.

Sign in / Sign up

Export Citation Format

Share Document