Bacterial sepsis and meningitis

Neonatal purulent meningitis in southern Tunisia: Epidemiology, bacteriology, risk factors and prognosis

OBJECTIVES

To study the epidemiological, clinical and bacteriological aspects and outcome of purulent neonatal meningitis (PNM).

METHODOLOGY

Retrospective analysis of 55 cases of PNM hospitalized in the pediatric ward of Hedi Chaker Hospital from 1990 to 2012. Infants less than 29 days of age were included. The diagnosis was made on either the presence of bacteria in the cerebrospinal fluid (CSF) or the combination of pleocytosis >30 cells/mm(3), protein level >1.3 g/l and glucose level <2.2 mmol/l or CSF/blood glucose ratio <0.4.

RESULTS

The male:female sex ratio was 1.75. One or more maternal risk factors for infection were found in 24 cases. The main symptoms were fever and poor feeding. Soluble antigen was positive in four cases and cultures had isolated the bacteria in 28 cases. The mortality rate was 40%. The sequelae rate in the survivors was 16.4%.

CONCLUSION

This study emphasizes the severity of PNM with high rates of mortality and neurological sequelae.

Diurnal fluctuation of leukocyte G6PD activity. A possible explanation for the normal neutrophil bactericidal activity and the low incidence of pyogenic infections in patients with severe G6PD deficiency in Israel

Acute hemolytic anemia associated with red blood cell (RBC) glucose-6-phosphate dehydrogenase (G6PD) deficiency is commonly encountered in the Mediterranean basin. Nevertheless, concomitant clinical evidence of white blood cell G6PD deficiency is extremely rare in Israel. This study sought to assess simultaneously levels of G6PD activity in polymorphonuclear leukocytes (PMN) and in red blood cells (RBC) of patients with G6PD deficiency, including full-term newborn infants. In PMN, the correlation between G6PD activity, hexose monophosphate shunt activity, and superoxide anion release was evaluated. In G6PD-deficient patients, a parallel and significantly decreased G6PD activity was found in neutrophils (range of activity 0-4.5 IU/10(6) PMN) and erythrocytes (range of activity 0-1.8 IU/g Hb), compared with healthy controls (5-23 IU/10(6) PMN and 2.4-6.4 IU/g Hb, respectively). A positive correlation was found in PMN between the levels of G6PD activity, hexose monophosphate (HMP) shunt activity, and superoxide anion release (p < 0.01). Nevertheless, all patients' bactericidal activity of neutrophils remained in the range of healthy controls. Although many episodes of acute hemolytic anemia were recorded, no increased incidence of pyogenic infections was observed in any group of patients investigated. Neutrophil and erythrocyte G6PD levels were re-assessed in some of these patients several times a day. A significant diurnal fluctuation of the enzyme activity was found. It is speculated that the patients produce fluctuating daily quantities of NADPH, sufficient to initiate the neutrophil respiratory burst and to achieve normal bactericidal activity, necessary to prevent the development of microbial infections.

Does the combined antenatal use of corticosteroids and antibiotics increase late-onset neonatal sepsis in the very low birth weight infant?

OBJECTIVE

The purpose of this study was to determine whether the combined use of maternal antenatal corticosteroids and antibiotic therapy is associated with an increased risk of late-onset neonatal sepsis among very low birth weight infants.

STUDY DESIGN

The outcomes of infants admitted to the 3 Cincinnati neonatal intensive care units between May 1991 and May 2000 were retrospectively evaluated. Late-onset neonatal sepsis was defined either as the occurrence of a positive blood culture obtained after 72 hours of life with clinical signs of sepsis or as the need for >5 consecutive days of antibiotic therapy for presumed sepsis that initiated after 72 hours of life. Wilcoxon rank sum, chi-square test, and multiple logistic regression were used for analysis.

RESULTS

Among the parturients delivering the study infants, 434 women (24%) received corticosteroids only, 175 women (9%) received antibiotics only, 819 women (46%) received both corticosteroids and antibiotics, and 370 women (20%) received neither corticosteroids nor antibiotics. Among 1978 study infants, there were 732 infants (41%) with late-onset neonatal sepsis. By univariate analysis, the odds ratio for late-onset neonatal sepsis caused by combined corticosteroid and antibiotic use was 0.96 (95% CI, 0.89%, 1.04%). Multiple logistic regression analysis was used to evaluate the risk of combined corticosteroids and antibiotic use after controlling for potential covariates and confounders. After controlling for outborn birth (odds ratio, 1.3; 95% CI, 1.0%-1.8%), increasing gestational age at delivery (odds ratio, 0.63; 95% CI, 0.60%-0.66%), interaction between white race and male gender (P =.01) and interaction between antibiotics and prolonged rupture of membranes (P =.02), the use of corticosteroids and antibiotics was not associated with an increased risk of late-onset neonatal sepsis (P =.9).

CONCLUSION

The combined use of maternal corticosteroids and antibiotic therapy is not associated with an increased risk for late-onset neonatal sepsis.

Effect of granulocyte and granulocyte macrophage colony stimulating factors (G-CSF and GM-CSF) on neonatal neutrophil functions

Although there are many studies on the effect of granulocyte and granulocyte-macrophage colony stimulating factors (G/GM-CSF) on adult neutrophil functions, there is little information regarding their influence on neonatal cells. We studied the in vitro effect of G/GM-CSF on neutrophil chemotaxis, polarization, and superoxide anion generation in 47 neonates compared with 35 adults. We found that G-CSF and GM-CSF significantly enhanced the chemotaxis of newborn infants' neutrophils, normalizing their chemotactic defect [from 35 +/- 7 cells/field (mean +/- SE) to 49 +/- 5 cells/field with G-CSF, p < 0.05 and to 55 +/- 4 cells/field with GM-CSF, p < 0.001]. It is notable that the maximal neutrophil response to the cytokines was observed particularly in the newborn infants with severe impairment in their chemotactic activity. Statistical analysis of the data showed a significant inverse correlation, which supported this observation (r = -0.6, p < 0.02 for G-CSF; r = -0.76, p < 0.001 for GM-CSF). The reduced polarization of neonatal compared with adult cells [71 +/- 5% versus 86 +/- 2% (mean +/- SE), p < 0.05], was corrected by CSF-priming (to 87 +/- 4% with G-CSF and to 92 +/- 2% with GM-CSF, p < 0.05). In addition, the neutrophil superoxide generation was significantly improved in both groups following the CSF-priming. GM-CSF and G-CSF gave comparable results in all functions studied except that GM-CSF improved superoxide release to a greater extent. This study shows a significant improvement of the neonatal neutrophil functions following in vitro CSF-priming and contributes to a better understanding of the neonatal neutrophil behavior when treated with G/GM-CSF.

The development of the complement system after 28 weeks' gestation

OBJECTIVE

To assess the levels and development of the various complement components in preterm infants, particularly among those born before 34 weeks' gestation.

SUBJECTS AND METHODS

We measured the complement system's activities (CH50 and AP50) as well as its various components (C1q,r,s, C2-C9, Factor B, and properdin) in 25 preterm infants [gestational age (GA) 28-33 weeks], 35 preterm infants (GA 34-36 weeks), 50 full-term newborn infants (GA 37-42 weeks), and 49 healthy adults as control subjects.

RESULTS AND CONCLUSIONS

The results of these studies are: (i) complement levels and activity were significantly reduced in preterm and full-term neonates when compared with adult levels, with the exception of C7 which was within the normal range in most infants. C8 and C9 were the most markedly reduced at all gestational ages. (ii) Complement levels correlated significantly with gestational age, but not with birth-weight, type of delivery, or gender. (iii) Between 28 and 33 weeks' gestation, there appeared to be almost no development of the complement system.