scholarly journals Gram negative organisms isolated from Blood Cultures and their Susceptibility Pattern

2021 ◽  
Vol 15 (5) ◽  
pp. 1074-1079
Author(s):  
Sadaf Munir ◽  
Saima Inam ◽  
Aqsa Aslam ◽  
Maria Aslam ◽  
Usman Nasir ◽  
...  

Background: Bloodstream infections (BSIs) are an important frequent health problem in terms of their high incidence and lethal outcomes. The bacteria that frequently cause bacteremia are Staphylococcus, Streptococcus, Enterococcus, Escherichia coli, Klebsiella, Enterobacter, Pseudomonas, Neisseria and Haemophilus. Gram negative rods constitute a significant bulk in BSIs. The bloodstream infections due to multidrug resistant pathogens are on the rise globally making treatment more challenging. Aim: To identify the gram negative organisms causing blood stream infections and assess their susceptibility pattern so as to provide guidance for the empirical treatment hoping for better clinical outcome. Methodology: A retrospective, cross-sectional descriptive study carried out in Pathology Laboratory of Sharif City Hospital, Lahore. All the blood culture samples received in Microbiology laboratory between June 2017 to June 2019 were included in the study by non-probability consecutive sampling. Blood cultures were proceeded by subculturing on 1st and 5th day on MacConkey and Blood agar. The colonies obtained were identified through gram staining and biochemical profile. API20E was used for Enterobacteriaceae. Antibiotic susceptibility testing of the pathogens was by Kirby Bauer disc diffusion method. Results: In the current study 663 blood cultures were analyzed. Only 11.9% exhibited positive microbial growth. 55.7% of the positive cultures revealed gram negative bacteria. Among the pathogens isolated, E.coli was found to be responsible for BSIs in 22.7% cases, followed by Salmonella Typhi 20.4% and Klebsiella pneumoniae 18.1%.The gram negative rods exhibited a very high resistance for penicillins, cephalosporins and fluoroquinolones. The efficacy of aminoglycosides and results for carbapenems susceptibility were hopeful. Conclusion: The study shows that the Gram negative bacteria causing BSIs have shown unsatisfactory susceptibility to most of the commonly prescribed antimicrobials. The rising drug resistance has a major impact on the selection and prescription of antibiotics and calls for judicious use of antibiotics. Keywords: Gram Negative Organisms, Blood Culture, Antimicrobial Susceptibility Pattern

2017 ◽  
Vol 66 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Fevronia Kolonitsiou ◽  
Matthaios Papadimitriou-Olivgeris ◽  
Anastasia Spiliopoulou ◽  
Vasiliki Stamouli ◽  
Vasileios Papakostas ◽  
...  

The aim of the study was to assess the epidemiology, the incidence of multidrug-resistant bacteria and bloodstream infections’ (BSIs) seasonality in a university hospital. This retrospective study was carried out in the University General Hospital of Patras, Greece, during 2011–13 y. Blood cultures from patients with clinical presentation suggestive of bloodstream infection were performed by the BacT/ALERT System. Isolates were identified by Vitek 2 Advanced Expert System. Antibiotic susceptibility testing was performed by the disk diffusion method and E-test. Resistance genes (mecA in staphylococci; vanA/vanB/vanC in enterococci; blaKPC/blaVIM/blaNDM in Klebsiella spp.) were detected by PCR. In total, 4607 (9.7%) blood cultures were positive from 47451 sets sent to Department of Microbiology, representing 1732 BSIs. Gram-negative bacteria (52.3%) were the most commonly isolated, followed by Gram-positive (39.5%), fungi (6.6%) and anaerobes bacteria (1.8%). The highest contamination rate was observed among Gram-positive bacteria (42.3%). Among 330 CNS and 150 Staphylococcus aureus, 281 (85.2%) and 60 (40.0%) were mecA-positive, respectively. From 113 enterococci, eight were vanA, two vanB and two vanC-positives. Of the total 207 carbapenem-resistant Klebsiella pneumoniae (73.4%), 202 carried blaKPC, four blaKPC and blaVIM and one blaVIM. A significant increase in monthly BSIs’ incidence was shown (R2: 0.449), which may be attributed to a rise of Gram-positive BSIs (R2: 0.337). Gram-positive BSIs were less frequent in spring (P < 0.001), summer (P < 0.001), and autumn (P < 0.001), as compared to winter months, while Gram-negative bacteria (P < 0.001) and fungi (P < 0.001) were more frequent in summer months. BSIs due to methicillin resistant S. aureus and carbapenem-resistant Gram-negative bacteria increased during the study period. The increasing incidence of BSIs can be attributed to an increase of Gram-positive BSI incidence, even though Gram-negative bacteria remained the predominant ones. Seasonality may play a role in the predominance of Gram-negative’s BSI.


2014 ◽  
Vol 3 (1) ◽  
pp. 35-40
Author(s):  
Biplob Kumar Raha ◽  
Nasim Jahan ◽  
Md Abdul Baki ◽  
Tahmina Begum ◽  
Nazmun Nahar ◽  
...  

Neonatal sepsis is one of the major causes of neonatal morbidity and mortality, particularly in developing countries. Epidemiology and surveillance of neonatal sepsis helps in implementation of rational empirical antibiotic strategy. A cross-sectional prospective study was conducted in the special care baby unit under department of Paediatrics and Neonatology, BIRDEM General Hospital during the period of November 2008 to September 2009 to determine the pattern of bacterial agents causing neonatal sepsis and their susceptibility pattern to various antimicrobial agents. Blood cultures were performed on admitted newborn babies (0-28 days) to rule out sepsis. Antimicrobial susceptibility testing was done for all blood culture isolates according to the criteria of the National Committee for Clinical Laboratory Standards by disk diffusion method. Out of 720 screened blood cultures, 64 (8.9%) reported as positive and the gram positive and gram negative bacteria accounted for 6 (9.4%) and 58 (90.6%) respectively. The most common gram positive organisms were Staphylococcus aureus (6.3%) and Enterococci (3.1%) & gram negative organisms were Klebsiella pneumoniae (37.5%), Serratia (25%), Pseudomonas aeruginosa (10.9%), Citrobacter (10.9%) and Acinetobacter (6.3%). The susceptibilities were remarkably low to Ampicillin (3.12 %) & Cefotaxim (10.9%) for both gram positive & gram negative isolates. Gram positive group had susceptibilities of 66.7% to Ciprofloxacin and Imipenem, 83.3% to Gentamicin, & 100% to Amikacin & Vancomycin. Gram negative isolates showed higher sensitivities to Imipenem (94.8%), Ciprofloxacin (89.7%), Amikacin (72.4%) respectively. Gram-negative bacteria showed high level of resistance to commonly used antibiotics (Ampicillin, Ceftazidim and Cefotaxim). Gentamicin, Amikacin, Imipenem and Ciprofloxacin were the most effective drugs compared to others. Routine bacterial surveillance and their sensitivity patterns must be an essential component of neonatal care. CBMJ 2014 January: Vol. 03 No. 01 P: 35-40


Author(s):  
Måns Ullberg ◽  
Volkan Özenci

Abstract Rapid identification and antimicrobial susceptibility testing remain a crucial step for early efficient therapy of bloodstream infections. Traditional methods require turnaround times of at least 2 days, while rapid procedures are often associated with extended hands-on time. The Accelerate Pheno™ System provides microbial identification results within 90 min and susceptibility data in approximately 7 h directly from positive blood cultures with only few minutes of hands-on time. The aim of this study was, therefore, to evaluate the performance of the Accelerate Pheno™ System in identification and antimicrobial susceptibility testing of both Gram-positive and Gram-negative bacteria directly from clinical blood culture samples. We analyzed 108 and 67 blood culture bottles using the Accelerate PhenoTest™ BC kit with software version v1.0 and the FDA-cleared version v1.2, respectively. Reliable identification was achieved for Enterobacteriaceae, staphylococci, and enterococci, with 76/80 (95%), 42/46 (91%), and 10/11 (91%) correct identifications. Limitations were observed in the identification of streptococci, including Streptococcus pneumoniae and Streptococcus pyogenes, and coagulase-negative staphylococci. Antimicrobial susceptibility results for Enterobacteriaceae, for amikacin, ertapenem, ciprofloxacin, gentamicin, meropenem, and piperacillin-tazobactam ranged between 86 and 100% categorical agreement. Using v1.2, results for ceftazidime showed 100% concordance with the reference method. For staphylococci, the overall performance reached 92% using v1.2. Qualitative tests for detection of methicillin or macrolide-lincosamide-streptogramin B (MLSB) resistance caused major and very major errors for isolates. Overall, the present data show that the Accelerate Pheno™ system can, in combination with Gram stain, be used as a rapid complementation to standard microbial diagnosis of bloodstream infections.


Author(s):  
Zineb Lachhab ◽  
Mohammed Frikh ◽  
Adil Maleb ◽  
Jalal Kasouati ◽  
Nouafal Doghmi ◽  
...  

Objectives.We conducted a one-year observational study from December 2012 to November 2013 to describe the epidemiology of bacteraemia in intensive care units (ICU) of Mohammed V Military Teaching Hospital of Rabat (Morocco).Methods.The study consisted of monitoring all blood cultures coming from intensive care units and studying the bacteriological profile of positive blood cultures as well as their clinical significance.Results.During this period, a total of 46 episodes of bacteraemia occurred, which corresponds to a rate of 15,4/1000 patients. The rate of nosocomial infections was 97% versus 3% for community infections. The most common source of bacteraemia was the lungs in 33%, but no source was identified in 52% of the episodes. Gram negative organisms were isolated in 83,6% of the cases withAcinetobacter baumanniibeing the most frequent. Antibiotic resistance was very high with 42,5% of extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae and 100% of carbapenemase inAcinetobacter baumannii. The antibiotherapy introduced in the first 24 hours was adequate in 72% of the cases.Conclusions.Bloodstream infections in ICU occur most often in patients over 55 years, with hypertension and diabetes. The bacteria involved are mainly Gram negative bacteria multiresistant to antibiotics. Early administration of antibiotics significantly reduces patients mortality.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4564-4564
Author(s):  
Marek Seweryn ◽  
Urszula Jarosz ◽  
Malgorzata Krawczyk-Kulis ◽  
Miroslaw Markiewicz ◽  
Grzegorz Helbig ◽  
...  

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(&minus;) 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.


2017 ◽  
Vol 55 (7) ◽  
pp. 2116-2126 ◽  
Author(s):  
Matthias Marschal ◽  
Johanna Bachmaier ◽  
Ingo Autenrieth ◽  
Philipp Oberhettinger ◽  
Matthias Willmann ◽  
...  

ABSTRACT Bloodstream infections (BSI) are an important cause of morbidity and mortality. Increasing rates of antimicrobial-resistant pathogens limit treatment options, prompting an empirical use of broad-range antibiotics. Fast and reliable diagnostic tools are needed to provide adequate therapy in a timely manner and to enable a de-escalation of treatment. The Accelerate Pheno system (Accelerate Diagnostics, USA) is a fully automated test system that performs both identification and antimicrobial susceptibility testing (AST) directly from positive blood cultures within approximately 7 h. In total, 115 episodes of BSI with Gram-negative bacteria were included in our study and compared to conventional culture-based methods. The Accelerate Pheno system correctly identified 88.7% (102 of 115) of all BSI episodes and 97.1% (102 of 105) of isolates that are covered by the system's identification panel. The Accelerate Pheno system generated an AST result for 91.3% (95 of 104) samples in which the Accelerate Pheno system identified a Gram-negative pathogen. The overall category agreement between the Accelerate Pheno system and culture-based AST was 96.4%, the rates for minor discrepancies 1.4%, major discrepancies 2.3%, and very major discrepancies 1.0%. Of note, ceftriaxone, piperacillin-tazobactam, and carbapenem resistance was correctly detected in blood culture specimens with extended-spectrum beta-lactamase-producing Escherichia coli ( n = 7) and multidrug-resistant Pseudomonas aeruginosa ( n = 3) strains. The utilization of the Accelerate Pheno system reduced the time to result for identification by 27.49 h ( P < 0.0001) and for AST by 40.39 h ( P < 0.0001) compared to culture-based methods in our laboratory setting. In conclusion, the Accelerate Pheno system provided fast, reliable results while significantly improving turnaround time in blood culture diagnostics of Gram-negative BSI.


2021 ◽  
Vol 8 (4) ◽  
pp. 327-332
Author(s):  
Humera Qudsia Fatima Ansari ◽  
Lubna Saher ◽  
Mustafa Afzal

: Blood cultures are a proven gold standard method for the identification of causative agents of bloodstream infections. Identification of causative organism along with antibiotic susceptibility plays a pivotal role in proposing suitable antibiotic therapy. Automated blood culture systems show improved monitoring of blood cultures by reducing the time and by ensuring more accurate results when compared to the conventional blood culture system. To isolate the organism from given blood samples of a suspected case of septicemia and to compare the results of conventional and automated blood culture systems and to study the antimicrobial susceptibility pattern of the pathogens isolated. A prospective study of 6 months period was conducted among 100 subjects attending the Department of Microbiology in a tertiary care hospital. Subjects with symptoms and signs of septicemia were included. 25ml of venous blood was drawn aseptically from the venipuncture site, of which 5ml of blood was inoculated into 50ml of Brain Heart Infusion bottle in conventional blood culture system and 10ml each into aerobic and anaerobic BACTEC PLUS bottle in Automated blood culture system BACTEC FX40. Overall, 48% and 60% of the samples revealed positive growth by the conventional and automated blood culture system BACTEC FX40, respectively. Gram Positive Cocci were 52.08% and Gram Negative Bacilli were 47.91% isolated by conventional blood culture system, whereas automated blood culture system BACTEC FX40 isolated 45% and 55%, respectively. Isolates were detected within 24-48hrs and 12-24 hrs by conventional and automated blood culture systems, respectively. The anti-microbial susceptibility pattern of the pathogens isolated was also recorded by Kirby Bauer disc diffusion method of antimicrobial susceptiblity testing. Automated blood culture systems are a trustworthy substitute to conventional blood culture systems. The automated blood culture systems being more sensitive and rapid in detecting septicemia in subjects acts as an appropriate means for the initial identification and detection of blood pathogens and improved provision of antimicrobial therapeutic options for septic Patients especially in Critical Care and Intensive Care Units where positive culture reporting is crucial.


2017 ◽  
Vol 06 (03) ◽  
pp. 132-133
Author(s):  
Preetam Kalaskar ◽  
Asha Anand ◽  
Harsha Panchal ◽  
Apurva Patel ◽  
Sonia Parikh ◽  
...  

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.


Author(s):  
Abigail R. Sopia ◽  
Pushpa Innocent D. Joseph ◽  
M. Kalyani ◽  
B. Ananthi ◽  
Suresh Dhanaraj ◽  
...  

Genital infections and subsequent vaginosis diagnosed through high vaginal swab in women is caused due to fungi or bacteria. The presented study focused on determining the types, numbers and antibacterial susceptibility pattern of aerobic bacteria causing vaginosis in 147 female patients attending infertility centre in Chennai, Tamil Nadu, India. Candida spp. caused 17% of infections with 15.7% of vaginosis caused by E.coli, Klebsiella spp., Acinetobacter spp., Citrobacter spp. and Gram positive cocci – Methicillin Sensitive Staphylococcus aureus (MSSA), Coagulase Negative Staphylococci(CONS), Staphylococcus aureus and Enterococcus spp. causing 12.9% of vaginitis in the study population. A total of 20 different antibiotics – cell wall inhibitors, protein synthesis inhibitors and nucleic acid synthesis inhibitors; were tested to determine the response of bacterial isolates by Kirby-Bauer disc diffusion method. The study result determined that the most effective drug for treating Gram positive bacterial vaginitis as per CLSI guidelines based on susceptibility pattern as: Linezolid(100%), Gentamycin(91.6%), Amikacin(87.5%),Erythromycin(79.2%), Co-Trimoxazole(72.2%), Ciprofloxacin(65.6%) and least Chloramphenicol(44.3%). High level gentamycin(83.3%) was found to be effective in treating Enterococci. The descending order of susceptibility of Gram negative aerobacteria causing vaginitis as per CLSI guidelines are: Amikacin(87.5%), Gentamycin(82.5%), Cefoperazone sulbactam (76.3%), Ciprofloxacin(68.5%), Ceftazidime(62.5%) and least Amoxyclav(25%).All Gram negative bacteria tested were susceptible to– Imipenem and Meropenem as well as Chloramphenicol. Ceftriaxone (87.5%) and Nitrofurantoin(72.3%) among other antibiotics was effective against Gram negative bacteria while all Enterobacteriaceae members were found to be resistant to tetracycline.


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S116-S117
Author(s):  
Connor Deri ◽  
Whitney Nesbitt ◽  
George Nelson ◽  
Jessica Keefe

Abstract Background Bloodstream infections are a leading cause of mortality amongst hospitalized patients. Optimizing time to pathogen identification and receipt of appropriate antibiotic therapy significantly decreases mortality, morbidity, and length of hospitalization. Rapid diagnostic tests, such as Verigene, assist in the early identification of bacteria and resistance determinants from positive blood cultures; however, Verigene assays are limited to the detection of 13 gram-positive and 9 gram-negative bacteria. Methods The purpose of this study was to describe gram-negative and gram-positive aerobic bacteria identified from positive blood cultures with no Verigene target detected and to use the susceptibilities to create an antibiogram to assist in empiric antibiotic selection. A total of 2325 positive blood cultures resulted between January 2017 and October 2018 underwent Verigene testing. Results Of the 2325 isolates, 383 (16.5%), had no Verigene organism or resistance mechanism detected. Of these, there were 239 (62.4%) gram-positive isolates, 141 (36.8%) gram-negative isolates, and 3 yeast isolates with 96 unique organisms. Seventy-six (19.8%) of the organisms identified by standard culture, but not Verigene testing, are included on Verigene panel. We analyzed nine common antibiotics active against gram-negative organisms to determine percent susceptibilities against the isolated aerobic pathogens: amikacin (92.1%), cefepime (93.5%), ceftazidime (94.0%), ceftriaxone (79.7%), ciprofloxacin (88.5%), gentamicin (91.9%), levofloxacin (86.9%), piperacillin–tazobactam (83.8%), and tobramycin (85.5%). Additionally, four antibiotics active against gram-positive organisms were analyzed for gram-positive susceptibilities: cefotaxime (91.8%), ceftriaxone (98.1%), levofloxacin (82.5%), and vancomycin (91.8%). Conclusion The results of this study provide clinicians with antibiotic susceptibilities against organisms that were not identified through Verigene to better guide timely and appropriate antibiotic therapy against gram-negative and gram-positive aerobic bacteria. Disclosures All authors: No reported disclosures.


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