Neonatal sepsis is a significant global health problem associated with high mortality and poor long-term outcomes for survivors particularly in under-resourced settings (22).
In one Egyptian study, the total mortality rate for the proven neonatal sepsis was 51% and 42.9% for EOS and LOS, respectively. Coagulase negative staphylococci were predominant isolates in both EOS and LOS followed by Klebsiella pneumoniae. Also they noticed that most of the bacterial isolates had low sensitivity to the commonly used empiric antibiotics. However, 70.1% exhibited multidrug resistance. Best sensitivities among Gram-positive isolates were found against imipenem, ciprofloxacin, vancomycin, and amikacin. (23)
We aimed in our study to assess the Platelet to Lymphocyte ratio (PLR) and the Neutrophil to Lymphocyte ratio (NLR) and determine their value as diagnostic markers for detection of EOS in Full-term newborns.
During sepsis or tissue infection Neutrophils are activated, causing their numbers in circulation to rapidly rise (24). Neutrophils are the most abundant leukocyte circulating in the bloodstream, comprising well over 50% of leukocytes, and these cells are particularly adept at phagocytosing and killing microbes (25).
Circulating platelet–neutrophil complexes occur in a diverse range of inflammatory disorders and sepsis). Activated platelets bind to neutrophils in the blood and mediate neutrophil recruitment to sites of injury and infection (26).
Though White blood cell count (WBC) is one of the routinely done diagnostic tests for sepsis work up, was believed to be reliable indicators of infection but now are known to be insensitive and nonspecific. Furthermore, a single leukocyte count obtained shortly after birth is not adequately sensitive for diagnosing neonatal sepsis (27).
We found that Cases had significant higher leucocyte count compared to controls indicating role of leukocytosis in diagnosis of neonatal sepsis (p = 0.004). also Cases had significant lower platelet count and lymphocytes compared to controls, this observation correlates relation of thrombocytopenia and neonatal morbidity as major conscequences of neonatal sepsis (p = 0.04). Also cases had significant increase in immature neutrophil count and I/T ratio compared to controls, this indicates the importance of CBC with differential in detecting early-onset neonatal sepsis (p = 0.0001)
IN Our study ,Comparing NLR and PLR between cases and controls, cases had significant higher values of these ratios rather than controls indicating their valuable role in detection of early-onset neonatal sepsis (p = 0.0001).
In our study CRP is important biomarker in the diagnosis of neonatal sepsis ,that agreed with (Sorsa and Abebe, 2018)(27), (Hotoura et al., 2012) (28) who reported that CRP is a useful diagnostic test for the early stages of neonatal sepsis reaching a peak during the first 24–48 hours with better sensitivity and specificity. (Albrich and Harbarth, 2015) (29), (Gilfillan and Bhandari, 2017)(30), (Ng et al., 2004)(31) and (Franz et al., 2004)(32) stated that diagnostic accuracy of CRP clearly improves by the combination with other biomarkers such as interleukins or procalcitonin. Our study revealed the significance of Procalcitonin as alternative biomarker to CRP in diagnosis of EONS,that agreed with (Chiesa et al., 2015)(33).
Morever our results are in contrary with (Çelik et al., 2016)(19) who reported that though, white blood cell (WBC) count ,immature/total leukocyte ratio (IT ratio), absolute leukocyte count and acute phase reactants such as C-reactive protein (CRP), procalcitonin (PC) and interleukin-6 (IL-6) are the most frequently used parameters for the diagnosis of newborn sepsis, these inflammatory markers, however, may be affected by maternal and fetal non-infectious conditions, and their different half-lives may decrease their ability to provide a definitive diagnosis of sepsis.
Our results show higher incidence of klebseilla in blood culture and these results agreed with (Vergnano et al., 2005)(34) who stated that Gram negative organisms are mainly represented by Klebsiella, Escherichia coli, Pseudomonas, and Salmonella, Gram positive organisms: Staphylococcus aureus, coagulase negative staphylococci (CONS), Streptococcus pneumoniae, and Streptococcus pyogenes. Isolated Neonatal surveillance in developed countries generally identifies GBS and E coli as the dominant EOS pathogens and CONS the dominant LOS pathogen followed by GBS and Staph aureus (Vergnano et al., 2005) (34). Our results shows that blood culture was significantly valuable in diagnosis of neonatal sepsis, this is consistent with (Walker et al., 2019)(35), (Arayici et al., 2019) (36) and (Wynn and J.L., 2016)(37) who stated that blood culture is the gold standard laboratory technique for diagnosis. (Weinbren et al., 2018) (38) found the same result that laboratory processing of blood cultures has remained static over the past 30 years, despite increasing antibiotic resistance and advances in analyser design.
On the other hand; even though blood culture is said to be the gold standard diagnostic test for sepsis, there are a number of limitations including; unavailability in the majority of developing country, associated technical problem and it takes more than three days to see at least the first preliminary result .As a result, the diagnosis of neonatal sepsis is based on clinical assessment and the management also rely on empirical treatment protocol which usually results in unnecessary hospital stay, increase irrational use of antibiotics and incur an unnecessary cost for the family (27).
From the results of our study we concluded that:
NLR, PLR are reliable predictive markers in detecting early onset neonatal sepsis as PPV of NLR was 98%, PLR was 72%..
Regarding to laboratory findings, Leucocytosis, thrombocytopenia, high CRP, high Procalcitonin and positive blood culture were associated with risk of neonatal sepsis.
NLR and PLR shows higher specificity results compared to CRP and Procalcitonin.