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.

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 POLA KUMAN BERDASARKAN PEWARNAAN GRAM PADA TINJA ANAK DENGAN DIARE DI RSUP PROF. DR. R. D. KANDOU MANADO

e-CliniC ◽  
2014 ◽  
Vol 2 (1) ◽  
Author(s):  
I Made Dwi Pramana
Keyword(s):  
Bacterial Infection ◽  
Microscopic Examination ◽  
Gram Negative Bacteria ◽  
Gram Stain ◽  
Gram Positive ◽  
Cross Sectional ◽  
Gram Negative ◽  
Consecutive Sampling ◽  
Gram Staining ◽  
In Infants And Children

Abstract: Background: Bacterial infection is one of the causes of diarrhea in infants and children. Bacteria are a group of microorganisms belongs to the prokaryotes which are structurally simpler than eukaryotics. There were many examinations used to detect the bacteria caused diarrhea, one of them was microscopic examination of the Gram stain smear. This technique is to determine whether the examination is Gram positive or Gram negative bacteria. Objective: This study aimed to determine the pattern of bacteria by Gram stain in children’s feces with diarrhea. Methods: This research used a descriptive designed with cross sectional approach by consecutive sampling from November to December 2013. There were 50 children in this study. Result: The results showed, 29 girls (58%) and 21 boys (42%). There were 34 children (68%) as the largest group that belongs to 1 - <3 years old. The results of feces microscopic examination showed 29 children (58%) got contaminated by bacteria. 23 children (46%) were contaminated with Gram positive and Gram negative bacteria. Gram negative Basil bacteria ware the most common bacteria that found in 23 preparations. Conclusion: Gram-negative bacilli germ were the most common germs that found in children’s feces with diarrhea and the numbers of diarrhea on November to December 2013 were increased. Key words: bacterial pattern, Gram staining, children, diarrhea  Abstrak: Latar belakang: Infeksi bakteri merupakan salah satu penyebab terjadinya diare pada bayi dan anak. Bakteri merupakan mikroorganisme yang termasuk dalam golongan prokariot yang strukturnya lebih sederhana dari eukariot. Banyak pemeriksaan yang dilakukan untuk mendeteksi bakteri penyebab diare, salah satunya dengan pemeriksaan mikroskopis pulasan yaitu pewarnaan Gram yang merupakan salah satu teknik pemeriksaan untuk menentukan apakah termasuk bakteri Gram positif atau bakteri Gram negatif. Tujuan penelitian: Penelitian ini bertujuan unutk mengetahui pola kuman berdasarkan pewarnaan Gram pada tinja anak dengan diare. Metode: Penelitian ini menggunakan desain penelitian deskriptif dengan pendekatan cross sectional yang dilakukan dengan cara consecutive sampling dari bulan November sampai Desember 2013. Sampel penelitian berjumlah 50 anak dan dilakukan pemeriksaan pewarnaan Gram. Hasil penelitian: Hasil penelitian didapatkan, perempuan 29 anak (58%) dan Laki-laki 21 anak (42%). Kelompok umur terbanyak 1 ─ <3 berjumlah 34 anak (64%). Hasil pemeriksaan mikroskopis feses ditemukan positif bakteri sebanyak 29 anak (58%). Bakteri Gram positif dan Gram negatif didapatkan berjumlah 23 anak (46%). Bakteri Basil Gram negatif merupakan bakteri terbanyak yang ditemukan yaitu 23 preparat. Kesimpulan: Kuman basil Gram negatif merupakan kuman terbanyak yang ditemukan pada tinja anak dengan diare dan terjadi peningkatan angka kejadian diare pada bulan November – Desember 2013. Kata kunci : pola kuman, pewarnaan Gram , anak, diare

scholarly journals Assessing Gram-stain error rates within the pharmaceutical microbiology laboratory

2020 ◽  
Author(s):  
Tim Sandle
Keyword(s):  
Error Rates ◽  
Microbiology Laboratory ◽  
Gram Stain ◽  
Clinical Context ◽  
Determinative Bacteriology ◽  
Gram Positive ◽  
Gram Negative ◽  
Microbial Identification ◽  
Gram Staining ◽  
Gram Negative Organisms

Gram-staining remains the fundamental method for determinative bacteriology, dividing bacteria into Gram-positive and Gram-negative organisms. This test provides information as to the origin of any contamination and is a pre-requisite for many microbial identification methods. Despite the longevity of the test, the test is highly reliant upon analyst technique and therefore errors occur. While there are a few studies looking at errors in the clinical context, research has not been extended to the pharmaceutical microbiology laboratory context. In this study, we present a review of over 6,000 Gram-stains and establish an error rate of around 3%, with the most common reason for error being an over-decolourisation step resulting in organisms that should be Gram-positive appearing as Gram-negative. The analysis enables others to benchmark their facilities against.

Assessment of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF- MS) for Accurate Bacterial Identification in Clinical Labs

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S143-S143
Author(s):  
M Abdel-Rahman ◽  
M S Azab ◽  
M Meibed ◽  
A El-Kholy ◽  
A W Elmetwalli
Keyword(s):  
Blood Cultures ◽  
Bacterial Identification ◽  
Gram Positive ◽  
Gram Negative ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Identification Of Bacteria ◽  
Vitek 2 ◽  
Phenotypic Methods ◽  
Tof Ms

Abstract Introduction/Objective On behalf of the diagnostic Medical Laboratory rapid, and accurate identification of bacteria with their one-to-one anti-microbial susceptibility outlines is of ultimate importance for the management of infected patients. Contemporary microbial identification methods employed in routine clinical diagnostic laboratories relies on the use of conventional phenotypic methods. Phenotypic methods are time consuming with minimum turn-around times of at least 24 hrs and in many occurrences of 48hrs. With the intention of accelerate laboratory processes the MALDI-TOF MS was familiarized. MALDI-TOF MS is established on proteomic profiling and permits for rapid identification of bacteria. This technology has not been widely used in Egypt, but has been regularly used in Europe for the past few years. Methods Two hundred forty three positive non duplicate blood cultures were accrued over a period of six months. Experimental aliquots were taken from excess sample material that was collected as part of routine clinical care. 105 were positive for Gram negative bacilli, 123 were positive for Gram positive cocci, 3 positive for Gram positive bacilli, and 7 were positive for yeast. MALDI-TOF identification was compared to conventional identification. Conventional identification consisted of a combination of MALDI-TOF identification of a subcultures colony by direct smear, biochemical reactions, Vitek 2, and molecular identification. Results Ninety seven of the one hundred and five blood cultures positive for Gram negative bacilli were monomicrobial. The majority of these were identified as Escherichia coli by conventional methods, followed by Klebsiella pneumoniae and Pseudomonas aeruginosa. Eighty-four of these monomicrobial cultures were identified by MALDI-TOF to the species level. Eighty-one of the eighty-four were concordant with the conventional identification (96.4%). Conclusion The MALDI-TOF proved to be useful for the rapid and reliable identification of g-ve bacteria from the clinical specimens. The difference in turnaround time for bacterial identification was significant between MALDI-TOF MS and VITEK 2 with minimal preparation for the blood cultures.

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

The Causative Organisms of Bacterial Meningitis and their Antimicrobial Resistance Profiles in Iranian Children in 2011-2016

2020 ◽  
Vol 20 (2) ◽  
pp. 229-236
Author(s):  
Sepideh Keshavarz Valian ◽  
Shima Mahmoudi ◽  
Babak Pourakbari ◽  
Maryam Banar ◽  
Mohammad Taghi Haghi Ashtiani ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Bacterial Meningitis ◽  
Medical Center ◽  
Blood Cultures ◽  
Gram Positive ◽  
Gram Negative ◽  
Number Of Patients ◽  
Resistance Patterns ◽  
Iranian Children ◽  
Surgery Department

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.

THE EFFECT OF SALMINE ON BACTERIA

1958 ◽  
Vol 4 (2) ◽  
pp. 65-71 ◽  
Author(s):  
Thomas D. Brock
Keyword(s):  
Sodium Chloride ◽  
Gram Negative Bacteria ◽  
Bacteriostatic Activity ◽  
Bactericidal Action ◽  
Gram Stain ◽  
Gram Positive ◽  
Gram Negative ◽  
Bacterial Surface ◽  
Bactericidal Effects

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.

scholarly journals Evaluation of MRSASelect™Chromogenic Medium for the Early Detection of Methicillin-ResistantStaphylococcus aureusfrom Blood Cultures

2013 ◽  
Vol 24 (4) ◽  
pp. e113-e116 ◽  
Author(s):  
Kanchana Manickam ◽  
Andrew Walkty ◽  
Philippe RS Lagacé-Wiens ◽  
Heather Adam ◽  
Barbara Swan ◽  
...  
Keyword(s):  
Early Detection ◽  
Antimicrobial Therapy ◽  
Predictive Value ◽  
Turnaround Time ◽  
Blood Cultures ◽  
Gram Stain ◽  
Chromogenic Medium ◽  
Gram Positive ◽  
Microbiological Methods ◽  
Gram Positive Cocci

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.

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