scholarly journals Molecular Epidemiology of Colonizing and Infecting Isolates of Klebsiella pneumoniae

mSphere ◽  
2016 ◽  
Vol 1 (5) ◽  
Author(s):  
Rebekah M. Martin ◽  
Jie Cao ◽  
Sylvain Brisse ◽  
Virginie Passet ◽  
Weisheng Wu ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Intestinal Tract ◽  
Susceptibility Testing ◽  
Empirical Therapy ◽  
Time Frame ◽  
Hospitalized Patients ◽  
Antibiotic Susceptibility Testing ◽  
Subsequent Infection ◽  
Content Type ◽  
Life Threatening

ABSTRACT K. pneumoniae commonly infects hospitalized patients, and these infections are increasingly resistant to carbapenems, the antibiotics of last resort for life-threatening bacterial infections. To prevent and treat these infections, we must better understand how K. pneumoniae causes disease and discover new ways to predict and detect infections. This study demonstrates that colonization with K. pneumoniae in the intestinal tract is strongly linked to subsequent infection. This finding helps to identify a potential time frame and possible approach for intervention: the colonizing strain from a patient could be isolated as part of a risk assessment, and antibiotic susceptibility testing could guide empirical therapy if the patient becomes acutely ill. Klebsiella pneumoniae is among the most common causes of hospital-acquired infections and has emerged as an urgent threat to public health due to carbapenem antimicrobial resistance. K. pneumoniae commonly colonizes hospitalized patients and causes extraintestinal infections such as urinary tract infection, bloodstream infection (septicemia), and pneumonia. If colonization is an intermediate step before infection, then detection and characterization of colonizing isolates could enable strategies to prevent or empirically treat K. pneumoniae infections in hospitalized patients. However, the strength of the association between colonization and infection is unclear. To test the hypothesis that hospitalized patients become infected with their colonizing strain, 1,765 patients were screened for rectal colonization with K. pneumoniae, and extraintestinal isolates from these same patients were collected over a 3-month period in a cohort study design. The overall colonization prevalence was 23.0%. After adjustment for other patient factors, colonization was significantly associated with subsequent infection: 21 of 406 (5.2%) colonized patients later had extraintestinal infection, compared to 18 of 1,359 (1.3%) noncolonized patients (adjusted odds ratio [OR], 4.01; 95% confidence interval, 2.08 to 7.73; P < 0.001). Despite a high diversity of colonizing isolates, 7/7 respiratory, 4/4 urinary, and 2/5 bloodstream isolates from colonized patients matched the patient corresponding rectal swab isolates, based on wzi capsular typing, multilocus sequence typing (MLST), and whole-genome sequence analysis. These results suggest that K. pneumoniae colonization is directly associated with progression to extraintestinal infection. IMPORTANCE K. pneumoniae commonly infects hospitalized patients, and these infections are increasingly resistant to carbapenems, the antibiotics of last resort for life-threatening bacterial infections. To prevent and treat these infections, we must better understand how K. pneumoniae causes disease and discover new ways to predict and detect infections. This study demonstrates that colonization with K. pneumoniae in the intestinal tract is strongly linked to subsequent infection. This finding helps to identify a potential time frame and possible approach for intervention: the colonizing strain from a patient could be isolated as part of a risk assessment, and antibiotic susceptibility testing could guide empirical therapy if the patient becomes acutely ill.

scholarly journals A Multiplex Fluidic Chip for Rapid Phenotypic Antibiotic Susceptibility Testing

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Pikkei Wistrand-Yuen ◽  
Christer Malmberg ◽  
Nikos Fatsis-Kavalopoulos ◽  
Moritz Lübke ◽  
Thomas Tängdén ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Antibiotic Susceptibility ◽  
Bacterial Infections ◽  
Susceptibility Testing ◽  
Empirical Therapy ◽  
Automated Image Analysis ◽  
Antibiotic Susceptibility Testing ◽  
Content Type ◽  
Broad Spectrum Antibiotics ◽  
Severe Infections

ABSTRACT Many patients with severe infections receive inappropriate empirical treatment, and rapid detection of bacterial antibiotic susceptibility can improve clinical outcome and reduce mortality. To this end, we have developed a multiplex fluidic chip for rapid phenotypic antibiotic susceptibility testing of bacteria. A total of 21 clinical isolates of Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were acquired from the EUCAST Development Laboratory and tested against amikacin, ceftazidime, and meropenem (Gram-negative bacteria) or gentamicin, ofloxacin, and tetracycline (Gram-positive bacteria). The bacterial samples were mixed with agarose and loaded in an array of growth chambers in the chip where bacterial microcolony growth was monitored over time using automated image analysis. MIC values were automatically obtained by tracking the growth rates of individual microcolonies in different regions of antibiotic gradients. Stable MIC values were obtained within 2 to 4 h, and the results showed categorical agreement with reference MIC values as determined by broth microdilution in 86% of the cases. IMPORTANCE Prompt and effective antimicrobial therapy is crucial for the management of patients with severe bacterial infections but is becoming increasingly difficult to provide due to emerging antibiotic resistance. The traditional methods for antibiotic susceptibility testing (AST) used in most clinical laboratories are reliable but slow with turnaround times of 2 to 3 days, which necessitates the use of empirical therapy with broad-spectrum antibiotics. There is a great need for fast and reliable AST methods that enable starting targeted treatment within a few hours to improve patient outcome and reduce the overuse of broad-spectrum antibiotics. The multiplex fluidic chip for phenotypic AST described in the present study may enable data on antimicrobial resistance within 2 to 4 h, allowing for an early initiation of appropriate antibiotic therapy.

scholarly journals A high-throughput fluidic chip for rapid phenotypic antibiotic susceptibility testing

2019 ◽  
Author(s):  
Pikkei Wistrand-Yuen ◽  
Christer Malmberg ◽  
Nikos Fatsis-Kavalopoulos ◽  
Moritz Lübke ◽  
Thomas Tängdén ◽  
...  
Keyword(s):  
High Throughput ◽  
Broad Spectrum ◽  
Antibiotic Susceptibility ◽  
Bacterial Infections ◽  
Susceptibility Testing ◽  
Empirical Therapy ◽  
Growth Media ◽  
Antibiotic Susceptibility Testing ◽  
Broad Spectrum Antibiotics ◽  
Growth Chambers

AbstractMany patients with severe infections receive inappropriate empirical treatment and rapid detection of bacterial antibiotic susceptibility can in this context improve clinical outcome and reduce mortality. We have to this end developed a high-throughput fluidic chip for rapid phenotypic antibiotic susceptibility testing of bacteria. A total of 21 clinical isolates of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus were acquired from the EUCAST Development Laboratory and tested against amikacin, ceftazidime and meropenem (Gramnegative bacteria) or gentamicin, ofloxacin and tetracycline (Gram-positive bacteria). The bacterial samples were mixed with agarose and loaded in 8 separate growth chambers in the fluidic chip. The chip was thereafter connected to a reservoir lid containing different antibiotics and a pump used to draw growth media with or without antibiotics into the chip for generation of diffusion-limited antibiotic gradients in the growth chambers. Bacterial microcolony growth was monitored using darkfield time-lapse microscopy and quantified using a cluster image analysis algorithm. Minimum inhibitory concentration (MIC) values were automatically obtained by tracking the growth rates of individual microcolonies in different regions of antibiotic gradients. Stable MIC values were obtained within 2-4 hours and the results showed categorical agreement to reference MIC values as determined with broth microdilution in 86% of the cases.ImportancePrompt and effective antimicrobial therapy is crucial for the management of patients with severe bacterial infections but is becoming increasingly difficult to provide due to emerging antibiotic resistance. The traditional methods for antibiotic susceptibility testing (AST) used in most clinical laboratories are reliable but slow with turnaround times of 2-3 days, which necessitates the use of empirical therapy with broad-spectrum antibiotics. There is a great need for fast and reliable AST methods that enable start of targeted treatment within a few hours to improve patient outcome and reduce overuse of broad-spectrum antibiotics. The high-throughput fluidic chip for phenotypic AST described in the present study enables data on antimicrobial resistance within 2-4 hours allowing for an early initiation of appropriate antibiotic therapy.

scholarly journals 1225. High Rate of Linezolid (LZD) Nonsusceptibility (LNS) Among Enteric Vancomycin-Resistant Enterococci (VRE) Recovered From Hospitalized Patients Actively Screened for VRE Rectal Colonization (VREC)

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S371-S372
Author(s):  
Thomas J Dilworth ◽  
Eric Beck ◽  
Rachel Pedersen ◽  
Waseem Al-Karkokly ◽  
Margaret Cook ◽  
...  
Keyword(s):  
Antibiotic Susceptibility ◽  
Susceptibility Testing ◽  
Hospitalized Patients ◽  
High Rate ◽  
Surgical Intensive Care Unit ◽  
Antibiotic Susceptibility Testing ◽  
Surgical Intensive Care ◽  
Logistic Regression Models ◽  
Level Data ◽  
Rectal Colonization

Abstract Background Select hospitalized patients are actively screened for VREC but VRE isolates may not undergo antibiotic susceptibility testing. We sought to identify predictors of daptomycin (DAP) nonsusceptibility (DNS, MIC &gt; 4) and LNS (MIC &gt; 2) among enteric VRE isolates recovered from patients actively screened for VREC for which antibiotic susceptibility testing was not preformed. Methods This was a retrospective study of consecutive adults admitted to a surgical intensive care unit (ICU) or associated medical unit between June 1, 2017 and March 1, 2018 who had a VRE isolate from active screening. Only index isolates were included. DAP and LZD MICs were determined by Etest. Patient- and antimicrobial-level data, including ambulatory prescriptions, dating back to January 1, 2016 were collected. Multivariable logistic regression models were used to determine predictors of DNS and LNS VRE. Results In total, 64 patients’ VRE rectal isolates were included. Fifty-nine (92.2%) were E. faecium and 50 (78.1%) were from ICU patients. Thirty-seven patients (57.8%) were female and the mean age ± SD was 60 ± 13 years. Five (7.8%) and 20 (31.3%) patients had previous abdominal transplant and VRE infection, respectively. DAP and LZD MIC distributions are shown in the table below. Forty-one (64.1%) VRE isolates were LNS, including five LZD-resistant isolates. Only one (1.6%) isolate was DNS precluding an analysis of DNS predictors; 12 (18.8%) isolates had a DAP MIC &gt; 2 mg/L. Common antimicrobial exposures prior to index VRE isolate included: vancomycin (62.5%), ceftriaxone (64.1%), cefepime (53.1%), metronidazole (50%), and ciprofloxacin (50%). Previous LZD (17.2%) and DAP (15.6%) exposure were less common. In a multivariable model, number of previous cefazolin doses (adjusted odds ratio (aOR) 0.74 95% confidence interval (CI) 0.55–0.95), and previous tobramycin exposure (aOR 0.15, 95% CI 0.02–0.81) were inversely associated with LNS. Previous LZD exposure was not associated with LNS. Conclusion LNS was common amongst VRE isolates in this cohort. Previous LZD exposure was infrequent and not associated with LNS. LZD susceptibility testing among VRE isolates recovered from patients actively screened for VREC warrants clinical consideration. Disclosures All authors: No reported disclosures.

scholarly journals The Search for a Practical Method for Colistin Susceptibility Testing: Have We Found It by Going Back to the Future?

2018 ◽  
Vol 57 (2) ◽  
Author(s):  
Michael J. Satlin
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Clinical Microbiology ◽  
Susceptibility Testing ◽  
Practical Method ◽  
Broth Microdilution ◽  
Excellent Performance ◽  
Gram Negative ◽  
Content Type ◽  
Carbapenem Resistant

ABSTRACTPolymyxins are relied upon for the treatment of carbapenem-resistant Gram-negative bacterial infections, but polymyxin resistance is increasing. Only broth microdilution is recommended for polymyxin susceptibility testing, but this method is impractical for most clinical microbiology laboratories. An article in this issue of theJournal of Clinical Microbiology(P. J. Simner, Y. Bergman, M. Trejo, A. A. Roberts, R. Marayan, T. Tekle, S. Campeau, A. Kazmi, D. Bell, S. Lewis, P. D. Tamma, R. Humphries, and J. A. Hindler, J Clin Microbiol 57:e01163-18, 2019,https://doi.org/10.1128/JCM.01163-18) found that colistin broth disk elution, a method that requires only colistin disks and broth, had excellent performance compared to broth microdilution for all strains exceptmcr-positiveEscherichia colistrains.

scholarly journals Current and Emerging Methods of Antibiotic Susceptibility Testing

Diagnostics ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 49 ◽  
Author(s):  
Zeeshan A. Khan ◽  
Mohd F. Siddiqui ◽  
Seungkyung Park
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Infection ◽  
Economic Burden ◽  
Antibiotic Susceptibility ◽  
Historical Perspective ◽  
Susceptibility Testing ◽  
Empirical Therapy ◽  
Pivotal Role ◽  
Disk Diffusion ◽  
Antibiotic Susceptibility Testing

Antibiotic susceptibility testing (AST) specifies effective antibiotic dosage and formulates a profile of empirical therapy for the proper management of an individual patient’s health against deadly infections. Therefore, rapid diagnostic plays a pivotal role in the treatment of bacterial infection. In this article, the authors review the socio-economic burden and emergence of antibiotic resistance. An overview of the phenotypic, genotypic, and emerging techniques for AST has been provided and discussed, highlighting the advantages and limitations of each. The historical perspective on conventional methods that have paved the way for modern AST like disk diffusion, Epsilometer test (Etest), and microdilution, is presented. Several emerging methods, such as microfluidic-based optical and electrochemical AST have been critically evaluated. Finally, the challenges related with AST and its outlook in the future are presented.

scholarly journals Enterobacterales Infection after Intestinal Dominance in Hospitalized Patients

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Krishna Rao ◽  
Anna Seekatz ◽  
Christine Bassis ◽  
Yuang Sun ◽  
Emily Mantlo ◽  
...  
Keyword(s):  
16S Rrna ◽  
Gene Sequencing ◽  
16S Rrna Gene Sequencing ◽  
Hospitalized Patients ◽  
Rrna Gene ◽  
Intestinal Colonization ◽  
Risk Of Infection ◽  
Subsequent Infection ◽  
Content Type ◽  
Rrna Gene Sequencing

ABSTRACT The Enterobacterales order of Gram-negative bacteria includes the common nosocomial pathogens Klebsiella pneumoniae, Escherichia coli, Serratia marcescens, and Enterobacter species. Intestinal domination by some colonizing bacterial taxa is associated with subsequent infection, but 16S rRNA gene sequencing is too costly and slow to be used in a clinical setting. The objectives of this study were to develop a PCR-based assay that can measure Enterobacterales density, validate it against 16S rRNA gene sequencing, and measure the association between Enterobacterales dominance and subsequent infection. Two quantitative PCR (qPCR) assays that were developed to quantify the absolute and relative abundance of Enterobacterales had good correlation with 16S rRNA sequence analysis (P < 0.0001). Using both PCR assays and 16S sequencing, a matched case-control study was performed comparing rectal swabs from hospitalized patients who later developed bloodstream, urinary tract, or respiratory Enterobacterales infections (n = 95) to swabs from patients who remained uninfected (n = 189). Enterobacterales abundance measured by sequencing was high in both cases and controls (means, 31.1% and 27.5%, respectively; P = 0.322). We observed an increased risk of infection that depended on both the absolute and relative abundance of Enterobacterales as measured by qPCR assay A (P = 0.012). After adjustment for albumin levels, central venous catheter presence, and use of cephalosporins at the time of swab collection, this association still approached significance (P = 0.061). These results demonstrate that using qPCR to measure intestinal colonization dominance is feasible, indicate that hospitalized patients have high levels of Enterobacterales colonization, and suggest that both relative and absolute abundance may be associated with subsequent infection. IMPORTANCE Increasing antibiotic resistance has resulted in infections that are life-threatening and difficult to treat. Interventions that prevent these infections, particularly without using antibiotics, could save lives. Intestinal colonization by pathogens, including vancomycin-resistant Enterococcus and carbapenem-resistant Enterobacteriaceae (part of the order Enterobacterales) is associated with subsequent infection, and increased colonization density is associated with increased infection risk. Therefore, colonization offers a window of opportunity for infection prevention if (i) there are rapid and inexpensive assays to detect colonization, (ii) there are safe and effective interventions, and (iii) the risk of infection outweighs the risk of the treatment. Fecal transplants are proof of principle that manipulating the microbiome can reduce such colonization and prevent infections. This study demonstrates the feasibility of implementing rapid and inexpensive assays to quantify colonization and measures the strength of association between Enterobacterales dominance and subsequent infection. The approach described here could be a valuable tool in the prevention of antibiotic-resistant infections.

scholarly journals Adverse Effects of Intravenous Vancomycin-Based Prophylaxis during Therapy for Pediatric Acute Myeloid Leukemia

2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Yilun Sun ◽  
Rachael L. Huskey ◽  
Li Tang ◽  
Hiroto Inaba ◽  
Aditya H. Gaur ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Bacterial Infections ◽  
Liver Toxicity ◽  
Antibacterial Prophylaxis ◽  
Content Type ◽  
Life Threatening ◽  
Stage Renal Disease ◽  
End Stage ◽  
Acute Myeloid

ABSTRACT Children and adolescents with acute myeloid leukemia (AML) are at risk of life-threatening bacterial infections, especially with viridans group streptococci. Primary antibacterial prophylaxis with vancomycin-based regimens reduces this risk but might increase the risks of renal or liver toxicity or Clostridium difficile infection (CDI). A retrospective review of data for patients treated for newly diagnosed AML at St. Jude Children's Research Hospital between 2002 and 2008 was conducted. Nephrotoxicity was classified according to pediatric risk, injury, failure, loss, and end-stage renal disease (pRIFLE) criteria and hepatotoxicity according to Common Terminology Criteria for Adverse Events (CTCAE) criteria. The risks of nephrotoxicity, hepatotoxicity, and CDI were compared between patients receiving vancomycin-based prophylaxis, no intravenous prophylaxis, or other prophylaxis. Generalized linear mixed models were used to address potential confounding. A total of 392 chemotherapy courses (108 with no intravenous prophylaxis, 218 with vancomycin-based prophylaxis, and 66 with other prophylaxis) for 111 patients were included. Development of pRIFLE risk, injury, and failure occurred in 190, 44, and 2 courses, respectively. Increases of at least one, two, and three grades for hepatotoxicity occurred in 189, 52, and 19 courses, respectively. After adjustment for confounders, vancomycin-based prophylaxis was not associated with nephrotoxicity or hepatotoxicity and reduced the risk of CDI, compared to no intravenous prophylaxis (0.9% versus 6.5%; P = 0.007) or other prophylactic regimens (0.9% versus 3.0%; P = 0.23). Despite concerns about vancomycin toxicity, vancomycin-based prophylaxis in pediatric patients with AML did not increase the risk of nephrotoxicity or hepatotoxicity and reduced the risk of CDI. Caution is advised to avoid contributing to antibiotic resistance.

scholarly journals Risk Factors for Klebsiella Infections among Hospitalized Patients with Preexisting Colonization

mSphere ◽  
2021 ◽  
Author(s):  
Krishna Rao ◽  
Alieysa Patel ◽  
Yuang Sun ◽  
Jay Vornhagen ◽  
Jonathan Motyka ◽  
...  
Keyword(s):  
Risk Factors ◽  
Health Care ◽  
Hospitalized Patients ◽  
Subsequent Infection ◽  
Content Type ◽  
Increased Risk ◽  
Health Care Associated Infections ◽  
Klebsiella Infections

Klebsiella is a leading cause of health care-associated infections. Patients who are intestinally colonized with Klebsiella are at a significantly increased risk of subsequent infection, but only a subset of colonized patients progress to disease.

scholarly journals A portable and high-integrated 3D microfluidic chip for bacterial quantification and antibiotic susceptibility testing

2021 ◽  
Author(s):  
Wenshuai Wu ◽  
Gaozhe Cai ◽  
Yang Liu
Keyword(s):  
Single Cell ◽  
Antibiotic Susceptibility ◽  
Bacterial Infections ◽  
Susceptibility Testing ◽  
Dynamic Range ◽  
Antibiotic Susceptibility Testing ◽  
Technical Potential ◽  
Uniform Sample ◽  
Pdms Chip ◽  
User Friendly

On-site single-cell antibiotic susceptibility testing (sc-AST) provides unprecedented technical potential to improve the treatment of bacterial infections and study heterogeneous resistance to antibiotics. Herein, we developed a portable and high-integrated 3D polydimethylsiloxane (PDMS) chip to perform fast and on-site bacteria quantification and sc-AST. The 3D arrangement of the chambers significantly improved the integration of reaction units (~10000/cm2) and widened the dynamic range to 5 orders of magnitude. A capillary valve-based flow distributor was adopted for flow equidistribution in 64 parallel channels and uniform sample loading in as short as 2 s. The degassed PDMS enabled this device to independently dispense the sample into 3D chamber array with almost 100% efficiency. The quantification of Escherichia coli (E. coli) strains with various activity was accomplished in 0.5-2 h, shortened by 20 h in comparison to the traditional plate counting. The functionality of our platform was demonstrated with several effective antibiotics by determining minimum inhibitory concentrations at single-cell level. Furthermore, we utilized the lyophilization of test reagents and needle-mediated reagents rehydration to realize one-step on-site sc-AST. The results indicate that the proposed sc-AST platform is portable, highly sensitive, fast, accurate and user-friendly, thus it has the potential to facilitate precise therapy in time and monitor the treatment. Meanwhile, it could serve as an approach for investigating the mechanisms of heteroresistance at single-cell resolution.

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