2 MATERIALS AND METHODS
The clinical and laboratory data of 151 consecutive inpatients aged over
60 years old who were tested by blood culture were retrospectively
analyzed from October 2022 to June 2023 at our hospital. If the
patient’s diagnosis at the time of admission or during hospitalization
was sepsis or septic shock, they were included according to the Survival
Sepsis Exercise Guidelines [6]. Subjects who
received their first dose of antibiotics more than 24 hours before
screening for inclusion in this investigation were excluded. Exclusion
criteria included pregnant women, immune-compromised patients receiving
radiation therapy or cytotoxic drugs, patients with AIDS, organ
transplant patients, patients with inherited immunodeficiency diseases,
patients with chronic kidney disease (baseline serum creatinine ≥2mg
/dL) or chronic liver failure (Child-Pugh grade C), patients with
bacterial endocarditis who require long-term treatment, and patients
with conditions impacting hematologic indices, such as hematologic
diseases, tumors, autoimmune diseases, and trauma. The study protocol
was approved by the Medical Ethics Committee of Fuding Hospital (The
ethnical approval number: Fuding Hospital 2022325).
Blood samples (2 ml) were drawn from the median elbow vein of patients
before treatment, and EDTA was used for anticoagulation. The Japanese
SYSMEX XE 2100 fully automated hematocrit analyzer and associated
reagents were employed for testing complete blood cell counts.
Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio
(PLR) were calculated based on the patient’s neutrophil count,
lymphocyte count, and platelet count obtained from routine blood tests.
The procedures were strictly adhered to, according to standard operating
procedures (SOPs), and all tests were completed during in-house quality
control.
Two sets of bilateral double vials were taken for blood culture, and
aerobic and anaerobic cultures were performed simultaneously. Blood
samples were obtained extracted from peripheral venous puncture of the
patients, directly injected into Bactec vials, and incubated in a Bactec
incubator (BD Diagnostics, Franklin Lakes, NJ, USA). Blood culture vials
were incubated at 37˚C for 7 days. Positive cultures were Gram-stained
and subcultured on solid media for subsequent analysis. Microbial
identification using conventional techniques and API systems
(bioMerieux, BacT/ALERT 3D, France).
A positive blood culture result from a single vial on one side was
considered positive for bacteria. When coagulase negativestaphylococcus, Propionibacterium, Corynebacterium, etc. are
isolated in blood culture, the same strain should be isolated
unilaterally or repeatedly at the same time, otherwise it is considered
as contaminated with colonizing bacteria of skin.
Data normality was evaluated using the Shapiro-Wilk test, with
non-normally distributed measurements expressed as median and quartiles
(P25-P75). Nonparametric tests were
utilized for intergroup comparisons: the Mann-Whitney U test for
two groups and the Kruskal-Wallis H test for multiple groups. Data that
conformed to a normal distribution were reported as mean ± standard
deviation, and the t-test was employed for mean comparisons between
groups. Categorical variables were measured using chi-square test
(χ 2) or exact Fisher’s tests, as appropriate,
and were reported as count (%). Receiver operating characteristic (ROC)
curve analyses were conducted for blood routine parameters. The area
under the ROC curve (AUC) for blood routine parameters was calculated to
determine the standard error and 95% confidence interval (95% CI). The
sensitivity, specificity, accuracy, positive predictive value, and
negative predictive value were calculated according to the ROC curves.
Statistical processing was carried out using SPSS 22.0 statistical
software (IBM SPSS, Armonk, NY, USA). A P - value of less than
0.05 was considered statistically significant.