MALDI-TOF identification of Gram-negative bacteria directly from blood culture bottles containing charcoal: Sepsityper® kits versus centrifugation–filtration method

Paenibacilli are efficient producers of potent agents against bacterial and fungal pathogens, which are of great interest both for therapeutic applications in medicine as well as in agrobiotechnol-ogy. Lipopeptides produced by such organisms play a major role in their inactivation potential. In this work we investigated two lipopeptide complexes, the fusaricidins and the polymyxins, produced by Paenibacillus polymyxa strains DSM 32871 and M1 by MALDI-TOF mass spectrometry. The fusaricidins show potent antifungal activities and are distinguished by an unusual variabil-ity. For strain DSM 32871 we identified numerous yet unknown variants mass spectrometrically. DSM 32871 produces polymyxins of type E (colistins), while M1 forms polymyxins P. For both strains novel, but not yet completely characterized polymyxin species were detected, which pos-sibly are glycosylated. These compounds may be of interest therapeutically, because polymyxins attain increasing attention as last-resort antibiotics against multiresistant pathogenic Gram-negative bacteria. In addition, the volatilomes of DSM 32781 and M1 were investigated with a GC-MS approach using different cultivation media. Production of volatile organic com-pounds (VOCs) was strain and medium dependent. In particular, strain M1 manifested as an effi-cient VOC-producer that exhibited formation of 25 volatiles in total. A characteristic feature of Paenibacilli is the formation of volatile pyrazine derivatives.

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Multiplex identification of gram-negative bacteria from positive blood culture broths : evaluation of an automated microarray-based molecular assay

10.5353/th_b5659578 ◽

2015 ◽

Author(s):

Man-po Tam

Keyword(s):

Blood Culture ◽

Positive Blood Culture ◽

Gram Negative Bacteria ◽

Molecular Assay ◽

Gram Negative

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ATG Use Is Associated with Frequent Occurrence of Positive Blood Cultures in Patients in the Early Phase After Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood.v118.21.4564.4564 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4564-4564

Author(s):

Marek Seweryn ◽

Urszula Jarosz ◽

Malgorzata Krawczyk-Kulis ◽

Miroslaw Markiewicz ◽

Grzegorz Helbig ◽

...

Keyword(s):

Stem Cell ◽

Hematopoietic Stem Cell Transplantation ◽

Blood Culture ◽

Stem Cell Transplantation ◽

Positive Blood Culture ◽

Blood Cultures ◽

Gram Negative Bacteria ◽

Hematopoietic Stem ◽

Gram Negative ◽

Gram Positive Bacteria

Abstract Abstract 4564 Background: Infectious complications remain an important cause of morbidity and mortality in the early phase after hematopoietic stem cell transplantation (HSCT). Aim: The aim of this study was to assess the frequency of positive blood cultures and its potential correlation with different studied parameters in large patient population studied in the first 30 days after HSCT. Material and methods: 431 patients at median age of 47 years (range 18–85) transplanted between 2009–2011 for hematological and non-hematological malignancies were included in our analysis. There were 242 males and 189 females. Results: The indications for autologous and allogeneic HSCT were following: AML – 105 (24%), NHL – 86 (20%), MM – 75 (17,5%), HL – 48 (11%), ALL – 40 (9%), MDS – 17 (4%), AA – 15 (3,5%), CML – 12 (2,8%), PNH – 11 (2,6%), connective tissue diseases – 5 (1,2%), CLL – 3 (0,7%) and other – 14 (3,2%). The following transplant procedures were performed: ABCT – 213 (49%), ABMT – 3 (0,7%), alloBCT – 56 (13%), alloBMT – 21 (5%), URDBCT – 87 (20%), URDBMT – 51 (12%). Pre-transplant ATG and anti-CD52 antibody were used in 142 (33%) and 5 (1.2%) patients, respectively. Amongst 431 transplanted patients, 495 blood cultures were collected; range 0–8 (median 1). Eighty seven blood samples were positive (17,6%). The following pathogens were detected: gram-positive bacteria in 48% (n=42), gram-negative bacteria in 38% (n=33), fungi in 1% (n=1) and both G(+) and G(−) bacteria in 13%(n=11). The gram-positive bacteria included: Staphylococcus epidermidis: 21 (50%), Micrococcus spp: 4 (9%), Enterococcus faecium: 3 (7%), Enterococcus faecalis: 3 (7%), Streptococcus haemolyticus: 3 (7%). The following gram-negative bacteria were found: Enterobacter cloacae: 10 (30%), Escherichia coli: 7 (21%), Pseudomonas aeruginosa: 5 (15%), Klebsiella pneumonia: 5 (15%). Candida albicans was detected only in one case. The use of ATG was associated with higher number of total blood draw and positive blood cultures. No significant correlation was found between the specific pathogen and the use of ATG. Male gender was associated with significantly higher number of blood sampling and with tendency to higher number of positive blood cultures. The type of conditioning regimen, the source of stem cell and the donor origin (auto vs sibling vs unrelated) did not influence the number of positive blood culture. There was tendency to higher number of blood intake, but not positive blood culture in patients transplanted in NR if compared to PR or CR. Conclusions: Positive blood cultures were positive in about 20% of patients after HSCT. Only pre-transplant ATG use was associated with the higher number of positive blood culture. Disclosures: No relevant conflicts of interest to declare.

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WS20.3 Use of matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry for identification of non-fermentative Gram-negative bacteria in cystic fibrosis and non-CF bronchiectasis

Journal of Cystic Fibrosis ◽

10.1016/s1569-1993(12)60143-x ◽

2012 ◽

Vol 11 ◽

pp. S45

Author(s):

A. Lake ◽

M. Ellington ◽

J.E. Foweraker

Keyword(s):

Mass Spectrometry ◽

Cystic Fibrosis ◽

Time Of Flight ◽

Laser Desorption ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Maldi Tof Mass Spectrometry ◽

Maldi Tof ◽

Matrix Assisted Laser ◽

Matrix Assisted Laser Desorption

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When first line treatment of neonatal infection is not enough: blood culture and resistance patterns in neonates requiring second line antibiotic therapy in Bangui, Central African Republic

BMC Pediatrics ◽

10.1186/s12887-021-02911-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Andrea Nebbioso ◽

Oluwakemi F. Ogundipe ◽

Ernestina Carla Repetto ◽

Calorine Mekiedje ◽

Hugues Sanke-Waigana ◽

...

Keyword(s):

Blood Culture ◽

Klebsiella Oxytoca ◽

Neonatal Infection ◽

Sub Saharan Africa ◽

Gram Negative Bacteria ◽

Third Generation ◽

Antibiotic Resistant ◽

Gram Negative ◽

Sub Saharan ◽

Third Generation Cephalosporins

Abstract Background Infectious diseases account for the third most common cause of neonatal deaths. Globally, antibiotic resistance (ABR) has been increasingly challenging neonatal sepsis treatment, with 26 to 84% of gram-negative bacteria resistant to third-generation cephalosporins. In sub-Saharan Africa, limited evidence is available regarding the neonatal microbiology and ABR. To our knowledge, no studies have assessed neonatal bacterial infections and ABR in Central-African Republic (CAR). Therefore, this study aimed to describe the pathogens isolated and their specific ABR among patients with suspected antibiotic-resistant neonatal infection admitted in a CAR neonatal unit. Methods This retrospective cohort study included neonates admitted in the neonatal unit in Bangui, CAR, from December 2018 to March 2020, with suspected antibiotic-resistant neonatal infection and subsequent blood culture. We described the frequency of pathogens isolated from blood cultures, their ABR prevalence, and factors associated with fatal outcome. Results Blood cultures were positive in 33 (26.6%) of 124 patients tested (17.9% for early-onset and 46.3% for late-onset infection; p = 0.002). Gram-negative bacteria were isolated in 87.9% of positive samples; with most frequently isolated bacteria being Klebsiella pneumoniae (39.4%), Escherichia coli (21.2%) and Klebsiella oxytoca (18.2%). All tested bacteria were resistant to ampicillin. Resistance to third-generation cephalosporins was observed in 100% of tested Klebsiella pneumoniae, 83.3% of isolated Klebsiella oxytoca and 50.0% of tested Escherichia coli. None of the tested bacteria were resistant to carbapenems. Approximately 85.7 and 77.8% of gram-negative tested bacteria were resistant to first-line (ampicillin-gentamicin) and second-line (third-generation cephalosporins) treatments, respectively. In hospital mortality, adjusted for blood culture result, presence of asphyxia, birth weight and sex was higher among neonates with positive blood culture (adjusted relative risk [aRR] = 2.32; 95% confidence interval [CI] = 1.17–4.60), male sex (aRR = 2.07; 95% CI = 1.01–4.26), asphyxia (aRR = 2.42; 95% CI = 1.07–5.47) and very low birth weight (1000–1499 g) (aRR = 2.74; 95% CI = 1.3–5.79). Conclusion Overall, 77.8% of confirmed gram-negative neonatal infections could no longer effectively be treated without broad-spectrum antibiotics that are not routinely used in sub-Saharan Africa referral hospitals. Carbapenems should be considered an option in hospitals with surveillance and antibiotic stewardship.

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

BioMed Research International ◽

10.1155/2016/1081536 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 2

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.

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