Subjects and Methods
Study Design:
This cross-sectional descriptive study will be conducted on admitted patients in
Cardiovascular Unit at the Tertiary Care Hospital in Port Said hospitals.
Subjects:
From each patient the following data will be collected: full medical history, symptoms
and signs, lab investigations including serum electrolytes, procalcitonin, liver and
kidney function tests, receipt of antibiotics and its response.
Inclusion criteria:
Patients diagnosed with sepsis based on medical history, lab investigations and
clinical picture.
Both sex, and all age-groups.
Exclusion criteria:
Patients diagnosed with sepsis proved by medical history, lab investigations and
clinical picture who received non-beta lactam antibiotics for the past 24 hours.
Samples proved contaminated by microbial flora will be rejected.
Methods:
Study design This study will be conducted at the tertiary care hospital which offers a
medical and surgery ICU and also has a cardiovascular Unit.
Epidemiologic and clinical information of patients and classification of the bacteremia
as Primary Bloodstream Infections (PBI), and Secondary Bloodstream Infections (SBI),
based on CDC criteria (5) and its National Healthcare Safety Network (NHSN) yearly
update.
Sample collection
Venous blood samples from cases with suspected sepsis, or bacteremia will be
incubated with a medium which encourages promotes bacterial growth.
We will take samples of 2 or more sets of aerobic and anaerobic blood cultures (3or
8 mL per small or large bottle)
Two blood cultures drawn from different areas are frequently enough to diagnose
bacteremia. Two out of 2 cultures growing identical type of bacteria often
represents a real bacteremia, in particular if the organism which grows isn't a
frequent contaminant.
Bacterial isolates from blood will be analysed by utilizing an automatic blood
culture system (Bact/Alert).
Positive samples will be cultured on different selective media. Primary organism
recognition will be done with matrix assisted laser desorption ionization time of
flight MS on a Vitek MS system (BioMerieux, Inc. France).
Calibration will be performed using standard strains to validate the run.
Minimum Inhibitory Concentration (MIC) outcomes will be interpreted based on the
Clinical and Laboratory Standards Institute (CLSI) protocols.
Biochemical tests which include CRP of Procalcitonin is most of time increased among
cases with BSI.
Sample size:
Number of Samples is calculated according to the next equation:
N= (Z α\2)²×P(1-P)\d² (Daniel, 2009) In which; N= the required sample size (Z α\2) = A
normal deviation reflect the type 1 error = 1.96 P = the prevalence of atypical bacteria
in sputum samples = (46%) (13). D = the accuracy of estimate (how close to the true
population) = 0.1
Thus; N= 60 blood samples.
Data Management and Statistical Analysis The results of the collected data will entered
into SPSS-19 program for statistical analysis.
Descriptive data will be managed based on its type; mean, SD and range will summarize
continuous data. While qualitative data will be summarized by frequencies.
With regard to analytic data, chi square test will be utilized to determine the
difference between qualitative data, while T test and ANOVA will be utilized to determine
the difference between quantitative data.
Ethical considerations
The samples will be collected from patients after taking written informed consent.
The study will be conducted after taking the permission from chairman of each
department.
The results of the patient will be confidential.
The patient will be informed of the results and will be treated accordingly.
The patient has the right to leave the study without compromising the patient's
treatment or the patient's relationship with the care provider.