Use of Acridine Orange Leukocyte Cytospin Test in Diagnosis of Neonatal Sepsis

Abstract

The early diagnosis of sepsis during the newborn period is an important problem because the early signs and symptoms of septicemia in term or preterm infants are usually nonspecific. 1,2 Examination of buffy coat smears stained with Gram, methylene blue or acridine orange (AO) stains or an acridine orange leukocyte cytospin (AOLC) test have been used as a rapid test for bacteremia. 2,3 However, studies evaluating AO-stained smears in detecting neonatal sepsis are scarce. [1][2][3][4] In this present study, blood culture was accepted as gold standard, and the results of concentrated blood smears stained with AO and Gram stain were compared. Our purpose was to determine whether the AOLC test is useful for further consideration in the diagnosis of neonatal sepsis.The study group consisted of 24 infants had a diagnosis of sepsis in Erciyes University, Faculty of Medicine Department of Pediatrics, Kayseri, Turkey. Physical examination, routine blood and urine analyses, sedimentation rate, C-reactive protein (CRP) assays, blood culture analysis and cerebrospinal fluid examination were performed in all infants. The blood smears prepared with cytospin centrifuge method were stained with Gram and AO. When two or more microorganisms were observed in the smear, it was accepted as positive. Of the 24 infants, nine (37.5%) were boys, 15 (62.5%) were girls and the age ranged from 12 h to 30 days (mean 10.89 ± 8.45 days). In 12 (50%) patients, various microorganisms were cultured from blood; enterococci, 3 Klebsiella pneumonia, 2 Escherichia coli, 2 coagulase-negative Staphylococci, 1 Staphylococcus epidermidis, 1 Group A beta hemolytic streptococci, 1 enterocbacter 1 and non-fermentative bacterium. 1 While bacteria were observed in 11 (91%) of 12 samples, which were prepared concentrated and stained with AO staining in the patients who were blood culture positive, bacteria were observed in two of the patients who were blood culture negative. While bacteria were observed in four (33.3%) of 12 samples, which were prepared concentrated and stained using a Gram stain, they were observed in two (16.6%) of the patients who were blood culture negative. While serum CRP was high in 11 (91%) of the patients who were blood culture positive, it was high in seven (58%) of the patients who were blood culture negative. White blood cell count was abnormal in nine (75%) and seven (58%) of the patients who were blood culture positive and negative, respectively. A shift to the left was reported in nine (75%) and eight (66%) of the patients who were blood culture positive and negative, respectively. The sensitivities of the AOLC test, Gram staining test, CRP assay, white blood cell count and shift to the left were found to be 91%, 50%, 91%, 75% and 75%, respectively. The specificities of the AOLC test, Gram staining test, CRP assay, white blood cell count and shift to the left were found to be 84%, 83%, 41%, 41% and 33%, respectively. Although the sensitivity of AOLC and CRP tests was found to be similar, the specificity of AOLC test was higher t...