What are the critical steps in processing blood cultures? A prospective audit evaluating current practice of reporting blood cultures in a centralised laboratory serving secondary care hospitals

2016 ◽  
Vol 70 (4) ◽  
pp. 361-366 ◽  
Author(s):  
Manjula Meda ◽  
James Clayton ◽  
Reela Varghese ◽  
Jayakeerthi Rangaiah ◽  
Clive Grundy ◽  
...  
Keyword(s):  
Blood Culture ◽  
Secondary Care ◽  
Rapid Identification ◽  
Antimicrobial Treatment ◽  
Blood Cultures ◽  
National Standards ◽  
Gram Stain ◽  
Gram Positive ◽  
Gram Negative ◽  
Common Intervention

AimsTo assess current procedures of processing positive blood cultures against national standards with an aim to evaluate its clinical impact and to determine the utility of currently available rapid identification and susceptibility tests in processing of blood cultures.MethodsBlood cultures from three secondary care hospitals, processed at a centralised laboratory, were prospectively audited. Data regarding processing times, communication with prescribers, changes to patient management and mortality within 30 days of a significant blood culture were collected in a preplanned pro forma for a 4-week period.ResultsOf 2206 blood cultures, 211 positive blood cultures flagged positive. Sixty-nine (3.1%) of all cultures were considered to be contaminated. Fifty per cent of blood cultures that flagged positive had a Gram stain reported within 2 hours. Two (0.99%) patients with a significant bacteraemia had escalation of antimicrobial treatment at the point of reporting the Gram stain that was subsequently deemed necessary once sensitivity results were known. Most common intervention was de-escalation of therapy for Gram-positive organisms at the point of availability of pathogen identification (25.6% in Gram positive vs 10% in Gram negative; p=0.012). For Gram-negative organisms, the most common intervention was de-escalation of therapy at the point of availability of sensitivity results (43% in Gram negatives vs 17.9% in Gram positive; p=0.0097). Overall mortality within 30 days of a positive blood culture was 10.9% (23/211). Antibiotic resistance may have contributed to mortality in four of these patients (three Gram negative and one Gram positive).ConclusionGram stain result had the least impact on antibiotic treatment interventions (escalation or de-escalation). Tests that improve identification time for Gram-positive pathogens and sensitivity time for Gram-negative pathogens had the greatest impact in making significant changes to antimicrobial treatment.

scholarly journals Evaluation of Verigene Blood Culture Test Systems for Rapid Identification of Positive Blood Cultures

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Jae-Seok Kim ◽  
Go-Eun Kang ◽  
Han-Sung Kim ◽  
Hyun Soo Kim ◽  
Wonkeun Song ◽  
...  
Keyword(s):  
Blood Culture ◽  
Resistance Genes ◽  
Rapid Identification ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Single Strain ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Susceptibility Tests

The performance of molecular tests using the Verigene Gram-Positive and Gram-Negative Blood Culture nucleic acid tests (BC-GP and BC-GN, resp.; Naosphere, Northbrook, IL, USA) was evaluated for the identification of microorganisms detected from blood cultures. Ninety-nine blood cultures containing Gram-positive bacteria and 150 containing Gram-negative bacteria were analyzed using the BC-GP and BC-GN assays, respectively. Blood cultures were performed using the Bactec blood culture system (BD Diagnostic Systems, Franklin Lakes, NJ, USA) and conventional identification and antibiotic-susceptibility tests were performed using a MicroScan system (Siemens, West Sacramento, CA, USA). When a single strain of bacteria was isolated from the blood culture, Verigene assays correctly identified 97.9% (94/96) of Gram-positive bacteria and 93.8% (137/146) of Gram-negative bacteria. Resistance genesmecAandvanAwere correctly detected by the BC-GP assay, while the extended-spectrumβ-lactamase CTX-M and the carbapenemase OXA resistance gene were detected from 30 cases cultures by the BC-GN assay. The BC-GP and BC-GN assays showed high agreement with conventional identification and susceptibility tests. These tests are useful for rapid identification of microorganisms and the detection of clinically important resistance genes from positive Bactec blood cultures.

scholarly journals Sepsis in cancer patients residing in Zimbabwe: Spectrum of bacterial and fungal aetiologies and their antimicrobial susceptibility patterns.

2019 ◽  
Author(s):  
FRANK CHINOWAITA ◽  
Wendy Chaka ◽  
Tinashe K Nyazika ◽  
Tendai C Maboreke ◽  
Emmanuel Tizauone ◽  
...  
Keyword(s):  
Blood Culture ◽  
Cancer Patients ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Treatment ◽  
Blood Cultures ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Patients With Cancer ◽  
Susceptibility Patterns

Abstract Introduction: Cancer and sepsis comorbidity is a major public health problem in most parts of the world including Zimbabwe. The microbial aetiologies of sepsis and their antibiograms vary with time and locations. Knowledge on local microbial aetiologies of sepsis and their susceptibility patterns is critical in guiding empirical antimicrobial treatment choices. Methods: This was a descriptive cross sectional study which determined the microbial aetiologies of sepsis from blood cultures of paediatric and adult cancer patients obtained between July 2016 and June 2017. The TDR-X120 blood culture system and TDR 300B auto identification machine were used for incubation of blood culture bottles and identification plus antimicrobial susceptibility testing, respectively. Clinical and laboratory standards institute (CLSI) standard breakpoints were used to interpret the antimicrobial susceptibility results. Results: A total of 142 participants were enrolled; 50 (35.2%) had positive blood cultures with 56.0% Gram positive, 42.0% Gram negative bacteria and 2.0% yeast isolates. Most common isolates were coagulase negative Staphylococcus spp. (CoNS) (22.0%), Escherichia coli (16.0%), Klebsiella pneumoniae (14.0%), Enterococcus faecalis (14.0%) and Staphylococcus aureus (8.0%) in all cancer patients. These isolates were similar in both haematological and solid cancers. Gram negative isolates exhibited high resistance to gentamicin (61.9%) and ceftriaxone (71.4%) which are the empiric antimicrobial agents used in our setting. Amikacin and meropenem showed 85.7% and 95.2% activity respectively against all Gram negative isolates while vancomycin and linezolid were effective against 96.2% and 100.0% of all Gram positive isolates respectively. Ten (66.7%) isolates of E. coli and K. pneumoniae were extended spectrum β-lactamase (ESBL) positive. Among Staphylococcus species it was also observed that 10/15 (66.7%) of the isolates were methicillin resistan t. Conclusions : The major microbial aetiologies of sepsis among patients with cancer in Zimbabwe were CoNS, E. coli , K. pneumoniae , E. faecalis and S. aureus . Most isolates were resistant to commonly used empirical antibiotics and there was high level of ESBL and methicillin resistance carriage. A nationwide survey on microbial aetiologies of sepsis and their susceptibility patterns would assist in the guidance of effective sepsis empiric antimicrobial treatment among patients with cancer.

scholarly journals Sepsis in cancer patients residing in Zimbabwe: Spectrum of bacterial and fungal aetiologies and their antimicrobial susceptibility patterns.

2019 ◽  
Author(s):  
FRANK CHINOWAITA ◽  
Wendy Chaka ◽  
Tinashe K Nyazika ◽  
Tendai C Maboreke ◽  
Inam Chitsike ◽  
...  
Keyword(s):  
Blood Culture ◽  
Cancer Patients ◽  
Antimicrobial Susceptibility ◽  
Methicillin Resistance ◽  
Antimicrobial Treatment ◽  
Blood Cultures ◽  
Gram Negative ◽  
E Coli ◽  
Patients With Cancer ◽  
Susceptibility Patterns

Abstract Introduction: Cancer and sepsis comorbidity is a major public health problem in most parts of the world including Zimbabwe. The microbial aetiologies of sepsis and their antibiograms vary with time and locations. Knowledge on local microbial aetiologies of sepsis and their susceptibility patterns is critical in guiding empirical antimicrobial treatment choices. Methods: This was a descriptive cross sectional study which determined the microbial aetiologies of sepsis from blood cultures of paediatric and adult cancer patients obtained between July 2016 and June 2017. The TDR-X120 blood culture system and TDR 300B auto identification machine were used for incubation of blood culture bottles and identification plus antimicrobial susceptibility testing, respectively. Results: A total of 142 participants were enrolled; 50 (35.2%) had positive blood cultures with 56.0% gram positive, 42.0% gram negative bacteria and 2.0% yeast isolates. Most common isolates were Coagulase Negative Staphylococcus (CoNS) (22.0%), Escherichia coli (16.0%), Klebsiella pneumoniae (14.0%), Enterococcus faecalis (14.0%) and Staphylococcus aureus (8.0%) in all cancer patients. These isolates were similar in both haematological and solid cancers. Amikacin and meropenem showed 85.7% and 95.2% activity respectively against all gram negative isolates while vancomycin and linezolid were effective against 96.2% and 100.0% of all gram positive isolates respectively. Ten (66.7%) isolates of E. coli and K. pneumoniae were extended spectrum β-lactamase (ESBL) positive and the same proportion was observed on methicillin resistance among Staphylococcus species. Conclusions: The major microbial aetiologies of sepsis among patients with cancer in Zimbabwe were CoNS, E. coli, K. pneumoniae, E. faecalis and S. aureus. Most isolates were resistant to commonly used empirical antibiotics and there was high level of ESBL and methicillin resistance carriage. A nationwide survey on microbial aetiologies of sepsis and their susceptibility patterns would assist in the guidance of effective sepsis empiric antimicrobial treatment among patients with cancer.

scholarly journals Antimicrobial Resistance Patterns of Bacterial Isolates from Blood Culture among HIV/AIDS Patients at Felege Hiwot Referral Hospital, Northwest Ethiopia

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Mohabaw Jemal ◽  
Teshiwal Deress ◽  
Teshome Belachew ◽  
Yesuf Adem
Keyword(s):  
Antimicrobial Resistance ◽  
Blood Culture ◽  
Agar Plate ◽  
Blood Cultures ◽  
Resistant Bacteria ◽  
Bacterial Isolates ◽  
Aids Patients ◽  
Gram Positive ◽  
Gram Negative ◽  
Hiv Aids

Background. The emergence and spread of antimicrobial resistance in bacteria is recognized as a global public health problem. Bloodstream infection with antimicrobial-resistant bacteria in HIV/AIDS patients makes the problem more challenging. So, regular and periodic diagnosis and use of the appropriate antimicrobial susceptibility pattern determination is the only option for decreasing the prevalence and development of drug-resistant bacteria. Methods. An institution-based cross-sectional study was conducted among 384 HIV/AIDS patients. Sociodemographic data of patients were recorded using structured questionnaires. Blood cultures were collected with BACTEC aerobic blood culture bottles. A pair of samples was collected from each patient aseptically and incubated at 37°. If samples are positive for bacterial agents, they were subcultured to solid media such as blood agar plate, chocolate agar plate, and MacConkey agar plates. Identification was performed using colony characteristics and standard biochemical techniques. The antimicrobial susceptibility test was determined by the Kirby–Bauer disc diffusion method. Data entry and analysis were performed while using SPSS version 20. Descriptive statistics were performed to calculate frequencies. Results. Altogether, 384 patients were included, and 123 blood cultures were positive, so that the yield was thus 32%. About 46 (37.4%) of Gram-negative and 77 (62.6%) of Gram-positive bacterial species were identified. Among Gram-negative bacterial isolates, K. pneumoniae was the leading pathogen, 19 (41.3%), whereas S. aureus, 38 (49.4%), was predominant among Gram-positive isolates. In his study, the majority of Gram-positive isolates showed high level of resistance to penicillin, 72 (95.5%), tetracycline, 55 (71.4%), and cotrimoxazole, 45 (58.4%). About 28 (73.6%) of S. aureus isolates were also methicillin-resistant. Gram-negative bacterial isolates also showed a high resistance to ampicillin (91.3%), tetracycline (91.3%), and gentamicin (47.8%). Overall, about 78% of multidrug resistance was observed. Conclusion. Several pathogens were resistant to greater than five antimicrobial agents, so that proper management of patients with bacteremia is needed, and a careful selection of effective antibiotics should be practiced.

scholarly journals Automated Interpretation of Blood Culture Gram Stains by Use of a Deep Convolutional Neural Network

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Kenneth P. Smith ◽  
Anthony D. Kang ◽  
James E. Kirby
Keyword(s):  
Neural Network ◽  
Blood Culture ◽  
Convolutional Neural Network ◽  
Clinical Laboratory ◽  
Clinical Microbiology Laboratory ◽  
Proof Of Concept ◽  
Gram Stain ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Cocci

ABSTRACTMicroscopic interpretation of stained smears is one of the most operator-dependent and time-intensive activities in the clinical microbiology laboratory. Here, we investigated application of an automated image acquisition and convolutional neural network (CNN)-based approach for automated Gram stain classification. Using an automated microscopy platform, uncoverslipped slides were scanned with a 40× dry objective, generating images of sufficient resolution for interpretation. We collected 25,488 images from positive blood culture Gram stains prepared during routine clinical workup. These images were used to generate 100,213 crops containing Gram-positive cocci in clusters, Gram-positive cocci in chains/pairs, Gram-negative rods, or background (no cells). These categories were targeted for proof-of-concept development as they are associated with the majority of bloodstream infections. Our CNN model achieved a classification accuracy of 94.9% on a test set of image crops. Receiver operating characteristic (ROC) curve analysis indicated a robust ability to differentiate between categories with an area under the curve of >0.98 for each. After training and validation, we applied the classification algorithm to new images collected from 189 whole slides without human intervention. Sensitivity and specificity were 98.4% and 75.0% for Gram-positive cocci in chains and pairs, 93.2% and 97.2% for Gram-positive cocci in clusters, and 96.3% and 98.1% for Gram-negative rods. Taken together, our data support a proof of concept for a fully automated classification methodology for blood-culture Gram stains. Importantly, the algorithm was highly adept at identifying image crops with organisms and could be used to present prescreened, classified crops to technologists to accelerate smear review. This concept could potentially be extended to all Gram stain interpretive activities in the clinical laboratory.

scholarly journals A comparative study of bloodstream infections in acute myeloid leukemia according to different phases of treatment: Can we predict the organism?

2017 ◽  
Vol 06 (03) ◽  
pp. 132-133
Author(s):  
Preetam Kalaskar ◽  
Asha Anand ◽  
Harsha Panchal ◽  
Apurva Patel ◽  
Sonia Parikh ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Blood Culture ◽  
Myeloid Leukemia ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Consolidation Therapy ◽  
Gram Positive ◽  
Gram Negative ◽  
Culture Positive ◽  
Acute Myeloid

Abstract Introduction: The treatment of acute myeloid leukemia (AML) consists of induction therapy with anthracyclines and cytarabine followed by two to four cycles of consolidation therapy with high-dose cytarabine after achieving remission. There have been very few studies comparing infections during induction and consolidation. We have analyzed blood cultures of patients with AML during episodes of fever occurring during induction and consolidation, for comparing the bloodstream infections in both the phases. Materials and Methods: Blood cultures of patients during febrile episodes were collected from central venous catheters and peripheral blood, both during induction and consolidation therapy of AML. Results: The study population included 52 AML patients. During induction, there were 52 episodes of fever and 25 (48%) blood cultures were positive, 15 of these blood cultures reported Gram-negative organisms, 9 reported Gram-positive organisms and 1 as yeast. During consolidation, 47 episodes of fever were recorded and blood cultures were positive in 12, of which 7 were Gram-negative, 5 were Gram-positive. Conclusion: The incidence of blood culture positive infections during therapy of AML at our center was higher. The predominant organism isolated was Gram-negative both during induction and consolidation. The incidence of blood culture positive infections had decreased by 50% during consolidation.

scholarly journals Misinterpretation of Gram Stain from the Stationary Growth Phase of Positive Blood Cultures for Brucella and Acinetobacter Species

2017 ◽  
Vol 11 (1) ◽  
pp. 126-131 ◽  
Author(s):  
Ali M. Bazzi ◽  
Jaffar A. Al-Tawfiq ◽  
Ali A. Rabaan
Keyword(s):  
Real Time Pcr ◽  
Blood Cultures ◽  
Blood Agar ◽  
Gram Stain ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Staining ◽  
Urease Test ◽  
Oxidase Test ◽  
Vitek 2

Introduction:Acinetobacter baumanniiandBrucellaspecies are Gram-negative organisms that are vulnerable to misinterpretation as Gram-positive or Gram-variable in blood cultures.Objective:We assess the random errors in gram stain interpretation to reduce the likelihood of such errors and therefore patient harm.Methodology:Aerobic and anaerobic blood cultures from two patients in an acute care facility in Saudi Arabia were subjected to preliminary Gram-staining. In case 1, VITEK-2 Anaerobe Identification, repeat Gram staining from a blood agar plate, Remel BactiDrop™ Oxidase test, Urea Agar urease test and real-time PCR were used to confirm presence ofBrucellaand absence ofCoryneformspecies. In case 2, repeat Gram- staining from the plate and the vials, VITEK-2 Gram-Negative Identification, real-time PCR and subculture on to Columbia agar, blood agar, and MacConkey agar were carried out to identifyA. baumannii.Results:In case 1, initially pleomorphic Gram-positive bacteria were identified.Coryneformspecies were suspected. Tiny growth was observed after 24 h on blood agar plates, and good growth by 48 h. Presence ofBrucellaspecies was ultimately confirmed. In case 2, preliminary Gram-stain results suggested giant Gram-positive oval cocci. Further testing over 18-24 h identifiedA. baumannii.Conclusions:Oxidase test from the plate and urease test from the culture vial is recommended after apparent identification of pleomorphic Gram-positive bacilli from blood culture, once tiny growth is observed, to distinguishBrucellafromCorynebacteriumspecies. If giant Gram-positive oval cocci are indicated by preliminary Gram-staining, it is recommended that the Gram stain be repeated from the plate after 4-6 h, or culture should be tested in Triple Sugar Iron (TSI) medium and the Gram stain repeated after 2-4 h incubation.

scholarly journals A Prospective Evaluation of Two Rapid Phenotypical Antimicrobial Susceptibility Technologies for the Diagnostic Stewardship of Sepsis

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Cesira Giordano ◽  
Elena Piccoli ◽  
Veronica Brucculeri ◽  
Simona Barnini
Keyword(s):  
Antimicrobial Susceptibility ◽  
Multidrug Resistant ◽  
Rapid Identification ◽  
Blood Cultures ◽  
Gram Positive ◽  
Gram Negative ◽  
Maldi Tof Ms ◽  
Gram Positive Bacteria ◽  
Maldi Tof ◽  
Tof Ms

Rapid identification of bloodstream pathogens by MALDI-TOF MS and the recently introduced rapid antimicrobial susceptibility testing (rAST) directly from positive blood cultures allow clinicians to promptly achieve a targeted therapy, especially for multidrug resistant microorganisms. In the present study, we propose a comparison between phenotypical rASTs performed in light-scattering technology (Alfred 60AST, Alifax®) and fluorescencein situhybridization (Pheno™, Accelerate) directly from positive blood cultures, providing results in 4–7 hours. Blood samples from 67 patients admitted to the Azienda Ospedaliero-Universitaria Pisana were analyzed. After the direct MALDI-TOF MS identification, the rAST was performed at the same time both on Alfred 60AST and Pheno. Alfred 60AST provided qualitative results, interpreted in terms of clinical categories (SIR). Pheno provided identification and MIC values for each antibiotic tested. Results were compared to the broth microdilution assay (SensiTitre™, Thermo Fisher Scientific), according to EUCAST rules. Using Alfred 60AST, an agreement was reached, 91.1% for Gram-negative and 95.7% for Gram-positive bacteria, while using Pheno, the agreement was 90.6% for Gram-negative and 100% for Gram-positive bacteria. Both methods provided reliable results; Alfred 60AST combined with MALDI-TOF MS proved itself faster and cheaper. Pheno provided identification and MIC determination in a single test and, although more expensive, may be useful whenever MIC value is necessary and where MALDI-TOF MS is not present.

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