The Diagnostic Value of Gram Stain for Initial Identification of the Etiologic Agent of Peritonitis in Capd Patients

1997 ◽  
Vol 17 (3) ◽  
pp. 269-272 ◽  
Author(s):  
Dinoráh A. Bezerra ◽  
Mario B. Silva ◽  
Jaqueline S.T. Caramori ◽  
Maria F. Sugizaki ◽  
Teruê Sadatsune ◽  
...  

Objective To evaluate the effectiveness of the Gram stain in the initial diagnosis of the etiologic agent of peritonitis in continuous ambulatory peritoneal dialysis (CAPD). Design Retrospective study analyzing the sensitivity (S), specificity (SS), positive predictive value (+PV), and negative predictive value (-PV) of the Gram stain relating to the results of cultures in 149 episodes of peritonitis in CAPD. The data were analyzed in two studies. In the first, only the cases with detection of a single agent by Gram stain were taken (Study 1). In the second, only the cases with two agents in Gram stain were evaluated (Study 2). Setting Dialysis Unit and Laboratory of Microbiology of a tertiary medical center. Patients Sixty-three patients on regular CAPD who presented one or more episodes of peritonitis from May 1992 to May 1995. Results The positivity of Gram stain was 93.2% and the sensitivity was 95.7%. The values of S, SS, +PV, and -PV were respectively: 94.9%, 53.5%, 68.3%, and 90.9% for gram -positive cocci and 83.3%, 98.8%, 95.2%, and 95.6% for gram-negative bacilli. The association of grampositive cocci plus gram -negative bacilli were predictive of growth of both in 6.8%, growth of gram -positive cocci in 13.7%, and growth of gram -negative bacilli in 72.5%. Conclusions The Gram stain is a method of great value in the initial diagnosis of the etiologic agent of peritonitis in CAPD, especially for gram-negative bacilli.

2013 ◽  
Vol 24 (4) ◽  
pp. e113-e116 ◽  
Author(s):  
Kanchana Manickam ◽  
Andrew Walkty ◽  
Philippe RS Lagacé-Wiens ◽  
Heather Adam ◽  
Barbara Swan ◽  
...  

INTRODUCTION:Staphylococcus aureusbacteremia is associated with considerable morbidity and mortality. In theory, reducing the turnaround time in reporting of methicillin-resistantS aureus(MRSA) among patients with bactermia could assist with the rapid optimization of antimicrobial therapy.OBJECTIVE: To evaluate the sensitivity and specificity of MRSASelect(Bio-Rad Laboratories, USA), a chromogenic medium, in the early detection of MRSA from blood cultures growing Gram-positive cocci in clusters, and to confirm that routine use of this medium would, in fact, reduce turnaround time for MRSA identification.METHODS: The present study was conducted at three microbiology laboratories in Manitoba. Between April 2010 and May 2011, positive blood cultures with Gram-positive cocci in clusters visualized on Gram stain were subcultured to both MRSASelectand routine media. MRSA isolates were identified using conventional microbiological methods from routine media and using growth with the typical colony morphology (pink colony) on MRSASelectmedium.RESULTS: A total of 490 blood cultures demonstrating Gram-positive cocci in clusters on Gram stain were evaluated.S aureuswas recovered from 274 blood cultures, with 51S aureusisolates (51 of 274 [18.6%]) identified as MRSA. MRSASelectmedium had a sensitivity of 98%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 99.8% for the recovery and identification of MRSA directly from positive blood culture bottles. In addition, use of MRSASelectmedium was found to improve turnaround time in the detection of MRSA by almost 24 h relative to conventional methods.DISCUSSION: These data support the utility of MRSASelectmedium for the rapid identification of MRSA from positive blood cultures. Further clinical studies are warranted to determine whether the improvement in turnaround time will result in a measurable reduction in suboptimal antimicrobial therapy and/or improvement in patient outcome.


2020 ◽  
Author(s):  
Stephen Shei-Dei Yang ◽  
Chun-Chun yang ◽  
Yi-Shen Chen ◽  
Shangjen chang

Abstract BackgroudTo compare the performance of the new flow cytometer UF-5000 with UF-1000i (Sysmex, Kobe, Japan) and Gram stain in predicting the bacterial patterns in urine samples MethodsWomen with symptoms suggestive of urinary tract infection were enrolled. Mid-stream urine sample was collected for gram staining, urine analysis and urine culture. Bacterial patterns were classified though UF1000i (none, cocci bacteria or rods/mixed growth), UF-5000 (none, cocci, rods or mixed growth) and Gram stain. Results Among the 102 samples, there were 10 gram-positive cocci, 2 gram-positive bacilli, 66 gram-negative rods, and 24 mixed growth. The sensitivity/specificity of the UF-1000i was 81.8/91.1% for gram-negative rods and 23.5/96.9% for cocci/mixed. The sensitivity/specificity of the UF-5000 was 80.0/88.2% for gram negative rods and 70.0/86.5% for gram-positive cocci.ConclusionsThe UF-5000 demonstrated the good sensitivity and specificity for Gram-negative bacilli bacteria and demonstrated an improved sensitivity for detecting Gram-positive cocci.


2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Kenneth P. Smith ◽  
Anthony D. Kang ◽  
James E. Kirby

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.


Author(s):  
Dietmar Enko ◽  
Ingeborg Stelzer ◽  
Michael Böckl ◽  
Wolfgang J. Schnedl ◽  
Andreas Meinitzer ◽  
...  

AbstractObjectivesRecently, the fully automated flow cytometry-based UF-5000 (Sysmex Corboration, Kobe, Japan) urine sediment analyzer was developed providing bacteria (BACT) info flags for more accurate bacterial discrimination of urinary tract infections (UTIs). This study aimed to compare the reliability of the UF-5000 BACT-info flags with manual Gram stain and urine culture as the gold standard method.MethodsA total of 344 urine samples were analyzed on the UF-5000 and compared with manual microscopic Gram stain and urine cultures. Agreement was assessed by Cohen’s kappa (κ) analysis. The Youden index was used to determine the optimal BACT and white blood cell (WBC) cut-off points for discriminating positive and negative urine cultures.ResultsOverall 98/344 (28.5%) samples were urine culture positive at a cut-off of ≥105 CFU/mL. “Gram-negative?” UF-5000 BACT-Info flags showed a better concordance of 25/40 (62.5%) with urine culture compared to Gram stain with 30/50 (60%). The results for UF-5000 discrimination of Gram-positive and Gram-negative microorganisms demonstrated a substantial (κ = 0.78) and fair (κ = 0.40) agreement with urine culture. Optimal cut-off points detecting positive urine cultures were 135 BACT/µL (sensitivity [SE]: 92.1%, specificity [SP]: 85.4%, positive predictive value [PPV]: 71%, negative predictive value [NPV]: 96%) and 23 WBC/µL (SE: 73.5%, SP: 84.1%, PPV: 65%, NPV: 89%).ConclusionsThe UF-5000 analyzer (Sysmex) is a reliable diagnostic tool for UTI screening. The displayed BACT-Info flags allow a quick diagnostic orientation for the clinician. However, the authors suggest verifying the automated Gram categories with urine culture.


2020 ◽  
Vol 20 (2) ◽  
pp. 229-236
Author(s):  
Sepideh Keshavarz Valian ◽  
Shima Mahmoudi ◽  
Babak Pourakbari ◽  
Maryam Banar ◽  
Mohammad Taghi Haghi Ashtiani ◽  
...  

Objective: The study aimed to describe the identity and antimicrobial resistance patterns of the causative agents of bacterial meningitis in children referred to Children’s Medical Center (CMC) Hospital, Tehran, Iran. Methods: This retrospective study was performed at CMC Hospital during a six-year period from 2011 to 2016. The microbiological information of the patients with a diagnosis of bacterial meningitis was collected and the following data were obtained: patients’ age, sex, hospital ward, the results of CSF and blood cultures, and antibiotic susceptibility profiles of isolated organisms. Results: A total of 118 patients with bacterial meningitis were admitted to CMC hospital. Sixty-two percent (n=73) of the patients were male. The median age of the patients was ten months (interquartile range [IQR]: 2 months-2 years) and the majority of them (n=92, 80%) were younger than two years of age. The highest number of patients (n=47, 40%) were admitted to the surgery department. Streptococcus epidermidis was the most frequent isolated bacterium (n=27/127, 21%), followed by Klebsiella pneumoniae (n=20/127, 16%), and Staphylococcus aureus (n=16/127, 12.5%). Blood culture was positive in 28% (n=33/118) of patients. Ampicillin-sulbactam and imipenem were the most effective antibiotics against Gram-negative bacteria isolated from CSF cultures. In the case of Gram-positive organisms, ampicillinsulbactam, vancomycin, and linezolid were the best choices. Imipenem was the most active drug against Gram-negative blood pathogens. Also, ampicillin and vancomycin had the best effect on Gram-positive bacteria isolated from blood cultures. Conclusion: Results of this study provide valuable information about the antibiotic resistance profiles of the etiologic agents of childhood meningitis, which can be used for prescription of more effective empirical therapies.


1958 ◽  
Vol 4 (2) ◽  
pp. 65-71 ◽  
Author(s):  
Thomas D. Brock

The bacteriostatic and bactericidal effects of salmine on various bacteria have been studied. Salmine has more bacteriostatic activity against Gram-positive than against Gram-negative bacteria. It is bactericidal in water but not in broth, and this bactericidal action occurs against both Gram-positive and Gram-negative bacteria. It has been shown that salmine causes agglutination of washed suspensions of certain bacteria and this agglutination is not correlated directly with the Gram stain. Salmine causes an increase in the turbidity of washed cells of all bacteria, Gram-positive and Gram-negative, and differs in this respect from the solutes sodium chloride and glucose, which affect only Gram-negative species.A comparison has been made of the effects of salmine and polymyxin and it has been concluded that salmine may also act by attachment to the bacterial surface.


2017 ◽  
Vol 34 (3) ◽  
pp. 128-134
Author(s):  
Md Abdus Salam ◽  
Md Robed Amin ◽  
Quazi Tarikul Islam

Introduction: Pneumonia is a worldwide, serious threat to health and an enormous socio-economic burden for health care system. According to recent WHO data, each year 3-4 million patients die from pneumonia. The clinical presentations and bacterial agents responsible for community acquired pneumonia (CAP) varies according to geography and culture.Methods: A cross sectional observational study conducted among the 53 consecutive patients with a clinical diagnosis of CAP in admitted patient in the department of Medicine, DMCH, during January 2010 to December 2010. Hematological measurements (TC of WBC, Hb%, ESR, platelet count), blood culture, chest X-ray P/A view, sputum for Gram staining and culture sensitivity, sputum for AFB, blood urea and random blood sugar were done in all cases. ELISA for IgM antibody of Mycoplasma pneumoniae and Chlamydia pneumoniae were done in sputum culture negative cases.Results: The mean (±SD) age was 38.9±17.3 years and Male female ratio was 3:1. Fever, chest pain and productive cough were the most common clinical features. The mean (±SD) respiratory rate was 23.0±2.8 /minute . COPD and DM were found in 17.0% and 5.7% of patients respectively . Blood culture was found positive in only 1.9% of the study patients. Gram positive Cocci 62.26%, Gram negative Bacilli 9.43%, mixed Gram positive cocci and Gram negative bacilli 11.32% and Gram negative Cocco Bacilli 1.9% were observed and in 15.03 % cases, no bacteria could be seen. Sputum culture revealed 53.8% streptococcus pneumoniae, 26.9% Klebsiella pneumonia as predominant organism. Mycoplasma pneumoniae and Chlamydia pneumoniae were found in 7.4% and 3.7% respectively by serological test. For Streptococcus pneumoniae, sensitive antibiotics were Amoxyclav and Levofloxacin. For Gram negative bacilli and coccobacilli, more sensitive antibiotics were Meropenem, Ceftriaxone, and Clarithromycin. The best sensitive drug were found meropenem. The mean (±SD) duration of hospital stay was 5.0±1.7 days with ranging from 3 to 10 days.Conclusion: Region based bacteroiological diagnosis of Cap is important for selecting the best and sensitive drugs for complete cure.J Bangladesh Coll Phys Surg 2016; 34(3): 128-134


2019 ◽  
Vol 20 (2) ◽  
Author(s):  
Anna Kędzia ◽  
Elżbieta Hołderna-Kędzia

Introduction. Cypress (Cupressus sempervirens L.) belongs to the family Cupressaceae. It is evergreen, and grows in Mediterranean region. The Cypress leaves and young branches are utilized to produce the essential oil. Cypress oil contain a number of components, in it α-pinene, Δ3-carene, α-terpinyl acetate, cedrol, α-terpinolene, β-myrcene, limonene, α-terpineolene, terpinen-4-ol, β-pinene, δ-cadinene and sabinene. The oil is used in therapy different diseases. It to have antimicrobial activity. Aim. The aim of the date was evaluation the susceptibility of anaerobic bacteria to Cypress oil. Material and methods. The anaerobic bacteria were isolated from patients. The 62 microorganisms, in it 36 strains of Gram-negative rods, 14 Gram-positive cocci and 12 Gram-positive rods, and 7 reference strains were tested. Susceptibility (MIC) was determined by means of plate dilution technique in Brucella agar supplemented with 5% defibrynated sheep blood, menadione and hemin. The Cypress oil was dissolved in DMSO and distilled water to obtain final following concentrations: 2.5, 5.0, 7.5, 10.0, 15.0 and 20.0 mg/ml. Inoculum containing 106 CFU per 1 ml was seeded with Steers replicator upon the agar with oil or without the oil (strains growth control). The agar plates was incubated in anaerobic condition in anaerobic jar in 37°C for 48 hrs. The MIC was interpreted as the lowest concentration of Cypress oil inhibiting the growth of tested bacteria. Results. The results indicated that from among Gram-negative rods the most susceptible to Cypress oil was the strains from genus Tannerella forsythia (MIC < 2.5-5.0 mg/ml), Bacteroides uniformis (MIC = 5.0 mg/ml), Bacteroides vulgatus and Porphyromonas asaccharolytica (MIC 5.0-7.5 mg/ml) and Porphyromonas levii (MIC = 7.5 mg/ml). The strains from genera Fusobacterium and of Bacteroides fragilis were the susceptible to 2.5-≥ 20.0 mg/ml. The Cypress oil was least active towards Prevotella and Parabacteroides strains (MIC ≥ 20.0 mg/ml).The tested Gram-positive cocci were more susceptible. The growth of the strains were inhibited by concentrations in ranges ≤ 2.5-7.5 mg/ml. The oil was minor active towards Gram-positive rods (MIC ≤ 2.5-20.0 mg/ml). Among the strains the genus of Actinomyces odontolyticus (MIC = 5.0 mg/ml) and Actinomyces viscosus (MIC ≤ 2.5-7.5 mg/ml) were the most susceptible. The growth of rods of Bifidobacterium breve was inhibited by concentrations 10.0 mg/ml. The data indicates that the Gram-negative rods were the less susceptible than Gram-positive bacteria to cypress oil. Conclusions. Among Gram-negative rods the most susceptible were the strains Tannerella forsythia, Bacteroides uniformis, Bacteroides vulgatus, Porphyromonas asaccharolytica and Porphyromonas levii. The oil was more active against Gram-positive cocci. Gram-positive anaerobic bacteria demonstrate the more susceptible to Cypress oil then Gram-positive rods.


2020 ◽  
Vol 5 (3) ◽  
pp. 145-150
Author(s):  
Claire Duployez ◽  
Frédéric Wallet ◽  
Henri Migaud ◽  
Eric Senneville ◽  
Caroline Loiez

Abstract. Introduction: A post-operative empirical antibiotic therapy (PEAT) is required in periprosthetic joint infections. It commonly uses broad-spectrum antibiotics to cover most Gram-positive cocci and Gram-negative bacilli. It is currently continued until first microbiological results are available, no less than five days later.Methods: We performed a retrospective study in order to evaluate duration of incubation required for surgical samples using the BacT/Alert® Virtuo blood culture bottles system.Results: Among 216 surgical interventions and 199 clinical strains (53.8% staphylococci, 22,1% streptococci and enterococci, 14,6% Gram-negative bacilli, 5,5% anaerobes), 90.5% of the strains were detected between day 0 and day 2; 15 infective strains are cultured from day 3 including 8 Cutibacterium sp., 4 staphylococci, 2 streptococci and 1 Enterococcus.Conclusions: We suggest that the duration of PEAT in patients operated for a periprosthetic joint infection may be shortened to three days as Gram-negative rods are unlikely to grow after three days of culture by using BacT/Alert® Virtuo blood culture bottles. This is likely to shorten the overall length of hospital stay, to diminish the occurrence of adverse side effects, and the emergence of antimicrobial resistance. However, coverage of Gram-positive cocci should be maintained for 14 days until the definite culture results are available.


2007 ◽  
Vol 28 (7) ◽  
pp. 825-831 ◽  
Author(s):  
David J. Weber ◽  
William A. Rutala ◽  
Emily E. Sickbert-Bennett ◽  
Gregory P. Samsa ◽  
Vickie Brown ◽  
...  

Objective.Nosocomial pneumonia is the leading cause of mortality attributed to nosocomial infection. Appropriate empirical therapy has been associated with improved survival, but data are limited regarding the etiologic agents of hospital-acquired pneumonia in non-ventilated patients (HAP). This evaluation assessed whether the currently recommended empirical therapy is appropriate for both ventilator-associated pneumonia (VAP) and HAP by evaluating the infecting flora.Design.Prospectively collected hospitalwide surveillance data was obtained by infection control professionals using standard Centers for Disease Control and Prevention definitions.Setting.A tertiary care academic hospital.Patients.All patients admitted from 2000 through 2003.Results.A total of 588 episodes of pneumonia were reported in 556 patients: 327 episodes of VAP in 309 patients, and 261 episodes of HAP in 247 Patients. The infecting flora in ventilated patients included gram-positive cocci (32.0% [oxacillin-susceptible Staphylococcus aureus {OSSA}, 9.25%; oxacillin-resistant Staphylococcus aureus {ORSA}, 17.75%]), gram-negative bacilli (59.0% {Pseudomonas aeruginosa, 17.50%; Stenotrophomonas maltophilia, 6.75%; Acinetobacter species, 7.75%), and miscellaneous pathogens (9.0%). The infecting flora in nonventilated patients included gram-positive cocci (42.59% [OSSA, 13.33%; ORSA, 20.37%]), gram-negative bacilli (39.63% [P. aeruginosa, 9.26%; S. maltophilia, 1.11%; Acinetobacter species, 3.33%), and miscellaneous pathogens (17.78%).Conclusions.Our data demonstrated that patients with HAP, compared with those with VAP, had a similar frequency of infection with ORSA but less commonly had infections due to P. aeruginosa, Acinetobacter species, and S. maltophilia. However, the overall frequency of infection with these pathogens was sufficiently high to warrant the use of empirical therapy likely to be active against them. Our data supports using the currently recommended empirical therapy for both HAP and VAP.


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