Therapeutic drug monitoring of amikacin in preterm and term neonates with late-onset sepsis. Can saliva samples replace plasma samples?

Amikacin is an aminoglycoside antibiotic that is frequently used for the treatment of neonatal late-onset sepsis, for which therapeutic drug monitoring (TDM) is advised. In order to decrease the TDM associated burden of plasma sampling, a noninvasive TDM method using saliva samples was investigated.

METHODS

This was a prospective single-centre, observational feasibility study with 23 premature and term neonates from whom up to 8 saliva samples were collected, together with residual plasma from clinical routine. Amikacin concentrations in saliva and plasma were quantified with liquid chromatography-tandem mass spectrometry. A population pharmacokinetic analysis was performed to develop an integrated pharmacokinetic model of amikacin in plasma and saliva and for the identification of covariates. TDM performance of different sampling regimens was evaluated using Monte Carlo simulations in a fictional cohort of representative neonates (n = 10 000).

RESULTS

Amikacin could be detected in saliva and a saliva compartment was appended to a 2-compartment plasma model. First-order absorption (k13 ) of the saliva compartment was 0.0345 h-1 with an interindividual variability of 45.3%. The rate of first-order elimination (k30 ) was 0.176 h-1 . Postmenstrual age had a significant negative covariate effect on k13 , with an exponent of -4.3. Target attainment increased from 77.6 to 79.2% and from 79.9 to 83.2% using 1-to 5 saliva samples or 1-5 plasma samples, respectively.

CONCLUSION

TDM of amikacin using saliva samples results in target attainment comparable to plasma samples and may be beneficial for (premature) neonates with late-onset sepsis.

Benzylpenicillin concentrations in umbilical cord blood and plasma of premature neonates following intrapartum doses for group B streptococcal prophylaxis

BACKGROUND AND METHOD

Dutch obstetrics guideline suggest an initial maternal benzylpenicillin dose of 2,000,000 IU followed by 1,000,000 IU every 4 h for group-B-streptococci (GBS) prophylaxis. The objective of this study was to evaluate whether concentrations of benzylpenicillin reached concentrations above the minimal inhibitory concentrations (MIC) in umbilical cord blood (UCB) and neonatal plasma following the Dutch guideline.

RESULTS

Forty-six neonates were included. A total of 46 UCB samples and 18 neonatal plasma samples were available for analysis. Nineteen neonates had mothers that received intrapartum benzylpenicillin. Benzylpenicillin in UCB corresponded to concentrations in plasma drawn directly postpartum (R2 = 0.88, p < 0.01). A log-linear regression suggested that benzylpenicillin concentrations in neonates remained above the MIC threshold 0.125 mg/L up to 13.0 h after the last intrapartum dose.

CONCLUSIONS

Dutch intrapartum benzylpenicillin doses result in neonatal concentrations above the MIC of GBS.

Predicting treatment response to vancomycin using bacterial DNA load as a pharmacodynamic marker in premature and very low birth weight neonates: A population PKPD study

Background: While positive blood cultures are the gold standard for late-onset sepsis (LOS) diagnosis in premature and very low birth weight (VLBW) newborns, these results can take days, and early markers of possible treatment efficacy are lacking. The objective of the present study was to investigate whether the response to vancomycin could be quantified using bacterial DNA loads (BDLs) determined by real-time quantitative polymerase chain reaction (RT-qPCR). Methods: VLBW and premature neonates with suspected LOS were included in a prospective observational study. Serial blood samples were collected to measure BDL and vancomycin concentrations. BDLs were measured with RT-qPCR, whereas vancomycin concentrations were measured by LC-MS/MS. Population pharmacokinetic-pharmacodynamic modeling was performed with NONMEM. Results: Twenty-eight patients with LOS treated with vancomycin were included. A one-compartment model with post-menstrual age (PMA) and weight as covariates was used to describe the time PK profile of vancomycin concentrations. In 16 of these patients, time profiles of BDL could be described with a pharmacodynamic turnover model. The relationship between vancomycin concentration and first-order BDL elimination was described with a linear-effect model. Slope S increased with increasing PMA. In 12 patients, no decrease in BDL over time was observed, which corresponded with clinical non-response. Discussion: BDLs determined through RT-qPCR were adequately described with the developed population PKPD model, and treatment response to vancomycin using BDL in LOS can be assessed as early as 8 h after treatment initiation.

Saliva as a sampling matrix for therapeutic drug monitoring of gentamicin in neonates: A prospective population pharmacokinetic and simulation study

Aims

Therapeutic drug monitoring (TDM) of gentamicin in neonates is recommended for safe and effective dosing and is currently performed by plasma sampling, which is an invasive and painful procedure. In this study, feasibility of a non‐invasive gentamicin TDM strategy using saliva was investigated.

Methods

This was a multicentre, prospective, observational cohort study including 54 neonates. Any neonate treated with intravenous gentamicin was eligible for the study. Up to eight saliva samples were collected per patient at different time‐points. Gentamicin levels in saliva were determined with liquid chromatography tandem mass‐spectrometry (LC–MS/MS). A population pharmacokinetic (PK) model was developed using nonlinear mixed‐effects modelling (NONMEM) to describe the relation between gentamicin concentrations in saliva and plasma. Monte Carlo simulations with a representative virtual cohort (n = 3000) were performed to evaluate the probability of target attainment with saliva versus plasma TDM.

Results

Plasma PK was adequately described with an earlier published model. An additional saliva compartment describing the salivary gentamicin concentrations was appended to the model with first‐order input (k₁₃ 0.023 h⁻¹) and first‐order elimination (k₃₀ 0.169 h⁻¹). Inter‐individual variability of k₃₀ was 38%. Postmenstrual age (PMA) correlated negatively with both k₁₃ and k₃₀. Simulations demonstrated that TDM with four saliva samples was accurate in 81% of the simulated cases versus 94% when performed with two plasma samples and 87% when performed with one plasma sample.

Conclusion

TDM of gentamicin using saliva is feasible and the difference in precision between saliva and plasma TDM may not be clinically relevant, especially for premature neonates.

[Prescription And Delivery's Survey Of Benzodiazepines In The Occurrence Of Addictions At Mbour's District]

Impact of the prescription and delivery of benzodiazepines in the occurrence of addictions in the district of Mbour.

INTRODUCTION

Benzodiazepines (BZD) are widely used nowadays and are at the origin of an addiction.

OBJECTIVES

The objective was to evaluate the quality of benzodiazepine prescribing and delivery in the Mbour department of Senegal and subsequently to implement an addictovigilance strategy. Thus, we studied the prescribing habits, the quality of delivery and identified the consumption habits of these drugs.

MATERIALS AND METHODS

It was a cross-sectional, prospective study with two questionnaires: addressed to patients and prescribers, conducted in pharmacies, hospitals, districts and Mbour health posts.

RESULTS

44% of BZD prescriptions were prescribed by doctors and especially general practitioner. 31.1% did not comply with the rules of prescription (marketing authorization). As for the dispensing rules, (85.3%) were dispensed without a prescription. The level of consumption was high in the 30-40 age group (43.95%) predominantly female (59%). Insomnia predominated as a reason for prescription (16.4%) on anxiety (11.94%) with (65.5%) dependence.

CONCLUSION

The abuses observed in the prescription, the delivery and consumption of BZD, constitutes a real health problem. Half of the consumers become addicted, hence the need for a national addictovigilance program.

Th1/Th2 Dichotomy in Obese Women with Gestational Diabetes and Their Macrosomic Babies

The aim of the study was to assess T cell differentiation and the modulation of inflammatory cytokines in obese and gestational diabetes mellitus (GDM) women and their macrosomic newborns. Hence, immediately after delivery, blood samples were collected through the mother's arm vein and the umbilical cordon vein. Biochemical parameters measured were HbA1C, glucose, insulin, triglyceride (TG), total cholesterol (Tchol), HDL cholesterol (HDLchol), and LDL cholesterol (LDLchol). T lymphocytes were purified from the total blood with Ficoll-Paque. The mRNA expression of inflammatory markers in T cells was determined by RT-qPCR. We observed that diabetic mothers exhibited higher HbA1C, glycemia, insulinemia, TG, Tchol, HDLchol, and LDLchol levels than control mothers. Glycemia was not significantly different between macrosomic and control newborns. However, insulinemia was high in macrosomic babies. TG, Tchol, HDLchol, and LDLchol were not significantly different between macrosomic and control babies. In diabetic mothers, mRNA expression of the Th1 cell subtype was significantly increased. Th1 markers were upregulated in babies born to diabetic women than in control newborns. However, expression of two Th2 markers (GATA3 and IL-4) was not significantly different between control and GDM women and between their respective newborns. Interestingly, IL-10 mRNA expression was decreased in diabetic mothers and their offsprings. The Th1/Th2 cytokine ratio was increased in GDM obese mothers and their macrosomic newborns, suggesting a proinflammatory status in these subjects.

[Impact of sickle cell trait on arterial stiffness in African subjects]

Sickle cell trait (SCT) is the benign condition of sickle cell disease. Often asymptomatic, the carriers of the sickle cell trait have hemorheological disturbances with increased oxidative stress compared to healthy subjects. These disturbances can lead to structural and functional changes in large vessels. The aim of the study was to measure arterial stiffness, an independent marker of subclinical atherosclerosis, SCT carriers compared to sickle cell anemia (SCA) subjects. Nine SCT carriers aged 32±9 years (7 men) were compared to 14 SCA subjects aged 29±9 years (2 men) and 22 control subjects aged 34±9 years (11 men) recruited by the National blood transfusion center (CNTS) in Dakar (Senegal). Arterial stiffness was assessed by measurement of the finger-toe pulse wave velocity (PWVft) using pOpmètre^® (Axelife SAS-France). The cardiovascular risk (CVR) was assessed according to the Framingham Laurier score. The SCT carriers had a higher PWVft (m/s) than SCA subjects (8.2±2.2 vs 6.1±0.9m/s, P=0.004) but not different from that of healthy controls (8.2±2.2 vs 7.4±1.8m/s, P=0.33). Linear regression showed a positive relationship between PWVft and the pulse pressure (PP) (P˂0.001; r²=0.39; F=13.20). The results show that the SCT carriers have stiffer arteries than SCA subjects. Linear regressions adjusted for age, mean arterial pressure (MAP) and PP, showed that only age and PP were independently correlated with arterial stiffness in the entire population.

[Comparative study of repolarization in professional footballers and in sedentary black senegalese]

The objective of this work is to study the EKG of Senegalese black football players in comparison with sedentary adults of the same age by focusing on repolarization. 100 high-level football players and 50 Senegalese black sedentary adults have each had 12 classic recordings. The ST segment elevation or depression presented no significant difference between both groups. Without taking into account the amplitude of the T wave, the frequency of the negative T waves in each recording was significantly higher in the soccer player's than in the sedentary group. Early repolarization is more frequent in the sportsmen's compared to the sedentary but without significant statistical difference. As for the QTc interval, no significant difference between the two groups was noted.

[Prevalence of child and teenage obesity in schools in Dakar]

Obesity is currently viewed as a serious worldwide public health issue. In this survey, we aim to determine its prevalence among schoolchildren and teenagers in Dakar. The sample of our survey consisted of 2,356 students aged 11-17, including 1,110 boys and 1,246 girls. For each of them, we have calculated their body mass index. Based on the higher value of the norm of that index, referred to the 97th percentile of Rolland-Cachera MF's curves, we have identified obese students according to their age and sex. The prevalence of obesity within our sample is 9.34%, with 2.88% for boys and 6.46% for girls. It is at its peak in the age of 11, though there is no significance (p > 0.05) in its decrease (from age 12 to 17). There are significantly (p < 0.05) more obese students in "catholic private" schools than in "public" schools where schooling is free. Child and teenage obesity is a reality in Dakar schools. Consequently, it is advisable to determine its nationwide prevalence to take on its prevention as well as its cure.

[Contribution of ATP-dependent potassium channels, nitric oxide and prostaglandins in increase of diaphgram arteriolar blood fow during diaphgram contraction]

ATP-sensitive potassium (K(ATP)) channels and nitric oxide (NO) have been suggested to contribute in mediating active hyperemia in diaphragm. However, no data is available in the current literature concerning their comparative contributions to arteriolar dilation during muscle contraction. The aim of this study was therefore to examine, by video microscopy in rats, the effects of superfusing the muscle with Krebs solution alone (group C), or Krebs solution containing either glybenclamide (3mdeltaM, a blocker of K(ATP), group GLY), or Nwdelta-nitro-L-arginine (300 mdeltaM, a NO synthase inhibitor, group NNA), or mefenamic acid (50 mdeltaM, a prostaglandin synthesis inhibitor, group MA) on second and third order of diaphragm (A2 and A3 respectively) arteriolar dilation elicited by 3 min muscle stimulation (40 Hz, train duration: 300 milliseconds, 90 cycles per min). In group C, A2 diameters increased by 67.5 +/- 1.9% referring to baseline at the end of the stimulation. This increase was significantly reduced in groups GLY and NNA (16.7 +/- 2.5% and 47.3 +/- 2.2% respectively, p < 0.001 as compared to group C) and was more important in group GLY than in group NNA (p < 0.001). By contrast, no difference in post-contraction diameter was observed between groups C and MA. Similar results were observed in A3 vessels. These results indicate that K(ATP) are more important mediators of functional diaphragm arteriolar dilation in rat than NO, whereas prostaglandins are not involved in this phenomenon.

[Study of cellularity in bronchoalveolar fluid and bronchial reactivity to histamine in a model of asthma in guinea pig]

INTRODUCTION

Several studies showed that the guinea pig represents the animal of choice in the study of the asthma and more exactly in the study of the bronchial hyperreactivity.

MATERIALS AND METHOD

In our model of asthma, guinea pigs were made sensitive with ovalbumine (OVA), a protein extracted from the white of egg, and provoked in a way repeated with aerosol challenge of OVA for the group OVA (1 challenge a day during six days). This group was compared with the group controls (C), animals injected with a salt solution (NaCl 0.9%) and receiving aerosol challenge of salt solution. The OVA group was subdivided into two groups: A studied group 6 hours after the aerosol challenge of OVA. A studied group 24 hours after the aerosol challenge of OVA.

RESULTS

We showed an increasing increase of airway hyperresponsiveness to increasing doses of histamine in all groups of animals. This increase was significantly more important 6 hours after the last aerosol challenge of OVA (early airway hyperreactivity, OVA-6 group, n = 8) that at 24 hours after the last aerosol challenge (late airway hyperreactivity, OVA-24 group, n = 8). We had also noted a modification of cellularity in bronchoalveolar lavage fluid with an increase of the total number of cells essentially by increase of the rate of eosinophilia in OVA-6 group (n = 6) compared with OVA-24 group (n = 6) and Control group (n = 6).

CONCLUSION

The model of bronchial hyperreactivity and modification of cellularity in guinea pig will allow us to envisage studies on the origin of differences of ability to react in the group OVA-6 and OVA-24 and to study the medicinal efficiency of plants used in Senegal in the treatment of the asthma.

[Comparative study of the effect of fasting during Ramadan on the glycaemia at rest in sportsmen and sedentaries]

The fast of Ramadan submits body to transient metabolic modifications; and decrease of glycaemia can be one of results. Physical exercise modifies rate of plasmatic hormones responsible for its regulation. The purpose of this study is to appreciate the influence of the fast on this biologic parameter in sportsmen and sedentaries. Thirty (30) healthy subjects (15 sportsmen of stamina and 15 sedentaries), with 25 years of average age were recruited. They have all a comparable diet. We excluded subjects having practised a physical exercise the day of the test. Capillary glycaemia was measured after weighed and physical exam, in 2 periods: in second Ramadan's fortnight, 15 minutes before food intake, two (2) months after Ramadan at least 4 hours at distance of the last meal. Comparisons were remitted in the test of Student, significant for p value lower than 0.05. During Ramadan, the glycaemia of the sportsmen at rest, is at one exception always superior or equal to that of the sedentaries. However, there is non significant difference as much during the fast as in normal food intake. Respective averages are 4.6 mmol/l, 0.15 and 4.5 mmol/l, 0.01 during Ramadan. They cross then in 4.8 mmol/l, 0.2 and 4.8 mmol/l, 0.4 in normal food intake. Landmark, the comparison of the averages from period to the other one in every group shows a significant difference only for the sedentaries. The return to normal food intake was expressed by an important gain in weight for all subjects. The fast of Ramadan has no notorious influence on sportsman's glycaemia contrary to that of sedentary. In other words, the sportsman administers better his stocks of glucose. Previous works however strongly advised against sports practice during Ramadan and more particularly the competitions, because, exercises of strong intensity can induce dehydration.

[Physical performance and thermoregulatory study of subjects with sickle cell trait during a sub-maximal exercise]

The sickle cell trait is a genetic abnormality of red blood cells. It is due to the mutation of a parental gene, which rest Its to the substitution of glutamic acid by valin on beta globin chain of haemoglobin. The possibility for sickle cell trait carriers (SCT) to present any disturbance during predominantly anaerobic and aerobic exercises is unclear. Ten (10) subjects with sickle cell trait and 10 subjects control were studied during exercise test on cycloergometer. They were all students of the National Institute of Popular Education and Sport of Dakar. The mean of environmental temperature was 26 degrees C and humidity was 60 to 80%. After haematological analysis, a submaximal muscular exercise for one hour with 75% of maximal heart rate was done. We have determined heart rate, blood pressure, rectal and skin temperature during exercise. Haematological parameters shown any significant difference between the two groups. No significant difference was found in cardiocirculatory variables during maximal exercise in cycloergometer between control group and sickle cell trait group. The two groups have done submaximal exercise during 1 hour without particular difficulty. We have not observed a significant difference between the two groups in cardiovascular variables, rectal and skin temperature during exercise, and after 3 minutes of rest. These results show that subjects with SCT have physical capacity comparable with control subjects during a sub maximal exercise for 1 hour. We can assure that subjects with SCT in our country may participate in sports competition, as well as normal subjects (HbAA).

[Antibiotic resistance of the most frequently isolated germs at the Fann University Teaching Hospital between January 1999 and December 2000]

Bacterial infections take up an important place in tropical pathology and have an increased death-rate. Among the causes of this strong mortality, the resistance of bacteria to antibiotics keeps a dominant part. We carried out, between January 1999 and December 2000 a study aiming to establish the distribution of the most frequently isolated germs at the Laboratory of Bacteriology of Fann Hospital, their sensibility to antibiotics and the different phenotypes of resistance. We noticed a predominance of enterobacteria (69.30%), notably Escherichia coli (56.76%) and Klebsiella pneumoniae (47.69%), but also Staphylococcus aureus (13.91%). Enterobacteria present 39.7% of resistant phenotypes to beta-lactams (E. coli: 61.75% and K. pneumoniae: 47.69%). Only the third generation cephalosporins and fluoroquinolons are constantly actives on enterobacteria, and 69% of S. aureus strains are resistant to methicillin, and so to all beta-lactams. Pseudomonas aeruginosa become difficult to overcome: 51.13% of the strains produce beta-lactamase. The quinolons are the most active antibiotics on this germ. It is very important to settle network that will be in charge to survey the evolution of these bacterial resistances.

[Resistance of bacteria and antibiotic prescription in Fann University Teaching Hospital, Dakar]

The objective of this study conducted in Fann University Teaching Hospital in Dakar, is to establish correlation beetwen the prescription and consummation of antibiotics in the one hand, and the susceptibility of strains isolated in this hospital on the other hand. An interview of medical practitioners and pharmacists was realised to appreciate the antibiotics used in the clinics, the bacteria taken aim, the criteria of choice, the place of antibiogram, the place of antibiotics in orders of medicines and pharmacists, the consummest family of antibiotics. In the lab, all of pathogen bacteria were tested by disc diffusion test (antibiogram) to appreciate the susceptibility to antibiotics. The results show that Enterobacteria represented 60.8% of isolates and among them, Escherichia coli (30.6%) was the most representative specie in hospitalized and non hospitalized patients. 52% of the strains of E. coli were susceptible to aminopenicillins in external patients, versus less than 35% in hospitalized. In Neurosurgery, Pseudomonas aeruginosa was the most frequent bacteria and all of the strains were susceptible to imipenem, dibekacin and ciprofloxacin. Beta-lactams were the most used drugs in the first place (78.8%), related to habits of prescription of medical staff and to avaibility of antibiotics. The choice of antibiotics must take the susceptibility of strains into account.

Decreased pulmonary and tracheal smooth muscle expression and activity of type 1 nitric oxide synthase (nNOS) after ovalbumin immunization and multiple aerosol challenge in guinea pigs

Pharmacological evidence supports a role of a transient decreased endogenous nitric oxide (NO) synthesis in ovalbumin (OVA)-induced early airway hyperresponsiveness in guinea pigs. However, no data are available regarding the expression and activity of the constitutive NO synthases (cNOS; NOS1 and NOS3, nNOS and eNOS, respectively) in this model. Therefore, we evaluated cNOS activity (conversion of L-[3H]arginine to L-[3H]citrulline in the presence of Ca2+ and calmodulin), nitrate and nitrite (NOx) concentration (modified Griess method), and NOS1 and NOS3 protein expression (Western blot) in lung homogenates and in the tracheal smooth muscle from OVA-immunized and multiple aerosol-challenged guinea pigs (six challenges, once daily). The expression and activity of the inducible NOS isoform (NOS2), the levels of exhaled NO, and the in vivo airway reactivity were also determined. Constitutive NOS activity and NO(x) concentration were significantly lower 6 h after the last OVA challenge as compared with saline exposure, being similar at 24 h. Expression of NOS1 paralleled cNOS activity, which was reduced 6, but not 24 h after OVA challenge. The decrease in NOS1 expression was accompanied by a significant decrease in the amounts of exhaled NO and by a maximal airway hyperresponsiveness to histamine. The levels of NOS3 were not modified at the two time points evaluated, and no NOS2 expression and activity were found at any time point. Similar modifications were observed in the tracheal smooth muscle. We conclude that OVA stimulation in immunized guinea pigs induced a transient reduction in NOS1 protein expression and activity in the respiratory system, which probably participates in airway hyperresponsiveness.

[Ammonia-gas poisoning: respiratory troubles evaluated by functional exploration]

The objective of our research is first to evaluate the defects in the respiratory function which have been noticed among patients suffering from ammonia poisoning during the accident at the SONACOS factory of Dakar in 1992. Secondly it is to set precisely the seriousness of the problem. This retrospective study is carried out on 50 patients examined at the Physiology and Functional Exploration Laboratory of the faculty of Medicine of Dakar University from March 1993 to October 1995. These patients have been submitted to at least two respiratory functional explorations. Ten of them have been treated for two years, thus benefiting from a spirographic control of these respiratory troubles already noticed. 58 % of the patients have developed an obstruction syndrome with the following specifities : fourteen patients out of 29 revealed a serious stoppage of the bronchi, twelve had a moderate bronchial obstruction, and three showed a minor bronchial obstruction. Besides, 34 % of the patients have developed a mixed syndrome with a minor restrictive component and a severe obstructive component. 8 % of the poisoned have presented a normal lung function testing. About the localisation of the respiration disorders at the level of the bronchial system, 61 % of the patients have shown an obstruction of the proximal, medial and distal bronchi. 26 % have presented obstruction of the distal bronchi, 13 % have shown an attack at their medial and distal bronchi. 5 patients out of 10 have shown any modification in their respiratory troubles while 3 of 10 have shown significant improvement. Then 2 out of 10 have shown degradation in their respiratory problems with an extension of bronchial obstruction. The ammonia poisoning has caused serious respiratory disorders related to the general and local toxic action of ammonia on the respiratory tract, its retention at their level and its effects on the respiratory function. The severity of the patent injuries incites to issue recommendations concerning the prevention of ammonia poisoning and the quick and efficient taking charge of the casualties in case of any accidental intoxication.

Anesthetic concentrations of riluzole inhibit neuronal nitric oxide synthase activity, but not expression, in the rat hippocampus

We hypothesized that anesthetic dose of riluzole, an inhibitor of glutamate neurotransmission, may affect the activity and/or expression of neuronal NOS (nNOS). Riluzole, N(G)-nitro-L-arginine-methyl ester (L-NAME) and 7-nitro indazole (7-NI) produced a concentration-related inhibition of nNOS activity in vitro. Riluzole competed with 7-NI for inhibition of nNOS activity, but had no effect on nNOS or endothelial NOS (eNOS) protein expression. Also, nNOS activity was significantly decreased in riluzole-anesthetized rats (40 mg kg(-1) i.p., -32+/-6% from controls, P<0.05). Therefore, blockade of nNOS activity may be involved in the anesthetic effects of riluzole in vivo.

Molecular characteristics and susceptibility to antibiotics of serogroup A Neisseria meningitidis strains isolated in Senegal in 1999

A total of 22 strains of Neisseria meningitidis isolated from cerebrospinal fluid samples of patients in Dakar, Senegal, in the course of an epidemic of meningococcal meningitis in 1999 were studied. All the strains were serogroup A, serotype 21:P1.9 and belonged to clonal subgroup III-1. The strains were resistant to sulphonamide, but were susceptible to ampicillin, ceftriaxone and chloramphenicol, which are used in the treatment of cerebrospinal meningitis in Senegal.

Tuberculosis-associated severe CD4+ T-lymphocytopenia in HIV-seronegative patients from Dakar. SIDAK Research Group

OBJECTIVES

To determine the frequency and associated features of severe CD4+ T-lymphocytopenia (<300 cells/mm(3)) in HIV-seronegative patients with tuberculosis.

METHODS

Statistical analysis of 430 consecutively enrolled HIV-seronegative inpatients with tuberculosis in two teaching hospitals in Dakar, Senegal.

RESULTS

The mean CD4 + cell count was 602+/-318.3 cells/mm(3). CD4 + cell counts were below 300 cells/mm(3)in 62 patients (14.4%). Patients with fewer than 300 CD4+ cells/mm(3)differed from those with higher counts in being less likely to have a positive smear for acid-fast bacilli; in having a higher frequency of extrapulmonary involvement (pleural effusion, adenopathy and miliary disease) and oral candidiasis; and in having smaller tuberculin reactions, lower haemoglobin levels, less cavitation and less patchy infiltration. After adjustment for gender and age, all differences remained except miliary disease.

CONCLUSIONS

A substantial percentage (14.4%) of HIV-seronegative hospitalized patients for tuberculosis in a West African country presented with severe CD4 + T-lymphocyte depletion and had clinical and radiographic features indicative of more advanced disease and accompanying immunodepression. These results and those already published suggest that tuberculosis should be regarded as one of the diseases associated with a subgroup of patients with "idiopathic CD4 + T-lymphocytopenia".

[Burkholderia cepacia isolation and characterization from hospital infections]

The evolution of reanimation and functional exploration techniques has led to and explosion of nosocomial infections. They are prevailing in Intensive Care and Neonatal Units. This study deals with B. cepacia strains isolated in 1996 in a pediatric hospital of the Dakar University Hospital Center, following the installation of tracheo-bronchial exhausters which are used for obstruction removal among children. The 44 B. cepacia strains examined come from 42 blood cultures done among 29 boys and 13 girls aged between 5 days and 7 years, and from 2 exhausters. After identification by API20 NE (bio Merieux), a standard antibiogram, a 3 characters biotyping (O.N.P.G., esculin, nitrate reductase) and a study of the polymorphism of the DNA enzymatic restriction profile obtained by an pulsed field electrophoresis are performed on the isolates. The contamination come from the exhausters. All the strains produce an orange-colored yellow pigment. Only an O.N.P.G. (+), nitrate reductase (+) biotype was identified. The antibiotic susceptibility profile is almost pathognomonic for the 44 tested strains: sensitivity (100%) to ceftriaxone, to ceftazidime, to aztreonam: to contrimoxazole (96%) and to chloramphenicol (91%). Search for widen spectrum beta-lactamses and antibiotics resistance plasmids was negative. However, those strains that are multiples resistant, discharge others 8.1. isofocal point beta-lactamases. The R.F.L.P. study demonstrated a unique profile. The B. cepacia transmission is the result of the installation of medical reanimation equipment that are not well taken care of. The nosocomial infections ascertained so far are ordinary bacteremias. Strain's phenotypical and genotypical identification shows the presence of only one clone. To overcome there nosocomial infections, hygienic measures have to be reinforced.

[Sensitivity to cotrimoxazole of bacteria isolated at the Central University Hospital of Fann, Dakar]

This study concern a survey of bacterial resistance to cotrimoxazole; 510 strains of Enterobacteria (167), Vibrio cholerae(206) and Staphylococcus aureus(137) were tested by disc diffusion and agar dilution methods. An interview was conducted with 86 health personals to appreciate the influence of prescription. Staphylococcus aureus were the most susceptible bacteria (13% of resistance), and Vibrio cholerae the most resistant (95%). Related to the gender, Enterobacteria present 43 to 72% of resistance. The data of interview show a very frequent use of cotrimoxazole, related to the disponibility and the accessibility of this drug.

[In vitro sensitivity to antibiotics in 178 strains of genital mycoplasma isolated from gynecology consultants in Dakar]

The susceptibility to antibiotics of 144 strains of Ureaplasma urealyticum and 34 strains of Mycoplasma hominis isolated in Dakar, Senegal, was determinated by MIC determination in a medium. Doxycyclin and minocyclin are active on more than 90% of the strains of U. urealyticum, and more than 80% of M. hominis strains. Over 93% of U. urealyticum strains are susceptible to all the macrolids and apparented tested (erythromycin, pristinamycin, josamycin), but the activity of lincomycin, pristinamycin and josamycin on M. hominis was found only for 70% of the strains. Fluoroquinolones, once adequately studied, could turn out to be a useful alternative in therapeutics.

[Urinary tract infections in Dakar: etiologies, therapeutic basis]

This prospective study, performed in Fann University Teaching Hospital from January 1st to December 31st 1998, concern 1446 samples of urine. Enterobacteria (87.56%) were the most frequent aetiology, and Escherichia coli (48.7%) was the leading species in this family. The strains of E. coli present more resistant profil to beta-lactams (70.27%). Fluoroquinolons are active on more than 80% of the strains responsible of urinary tract infection in Dakar.

[Role of nitric oxide in diaphragmatic dysfunction genesis during sepsis in rats]

Nitric oxide (NO) is a vasodilator agent that is cytotoxic and negatively inotropic in the heart. More recently, it has been shown that during sepsis there is a high amount of NO production by a NO synthase (NOS) that is inducible by cytokines. The aim of this study was to investigate the role of NO in the genesis of diaphragmatic dysfunction during sepsis. Rats were inoculated i.p. injection with 10 mg/kg of Escherichia coil endotoxin (E animals) or saline (C animals). Six hours after endotoxin or saline inoculation, diaphragmatic force and muscularc GMP (Cyclic guanosine monophosphate) were assessed by in vitro force frequency curves and ELISA method, respectively. As compared to C animals, E animals showed a significant decrease in diaphragmatic force for all the frequencies of stimulation (p < 0.01). This reduction was associated with a significant increase in muscular cGMP. Inhibition of NO synthesis in E animals with either dexamethasone (4 mg/kg IV, 45 min before endotoxin or saline) or NG-monomethyl-L-arginine (L-NMMA, 8 mg/kg IV, 90 min after endotoxin or saline) prevented the effects of endotoxin. However, no modification was seen with NG-monomethyl-D-arginine (D-NMMA), a molecule which does not inhibit NO synthesis. Administration of dexamethasone or L-NMMA in C animals did not induce any significant change in diaphragmatic force, and cGMP ratio. We conclude that NO has a contributive role in diaphragmatic dysfunction during Escherichia coli induced sepsis in rats.

Characterization of M. tuberculosis strains from west African patients by spoligotyping

Analysis of Mycobacterium tuberculosis strains was carried out using isolates collected from 69 Senegalese and 20 Ivory Coast tuberculosis patients. These 89 isolates were typed by means of the spoligotyping technique, showing clusterized populations of bacterial strains. In the Senegalese patients, 35 genetic profiles were observed with 10 clusters of spoligotypes from 44 isolates. Among Ivory Coast patients, 11 spoligotypes were found for 20 isolates. A particular cluster of isolates was evident both in Senegalese (10) and Ivory Coast (11) patients. These results show the existence of polymorphism of the direct repeat region for African M. tuberculosis strains. However they suggest that additionnal markers are needed for accurate epidemiological studies in areas that are highly endemic for tuberculosis.

Endogenous peroxynitrite mediates mitochondrial dysfunction in rat diaphragm during endotoxemia

It has been shown that nitric oxide (NO), synthesized by the inducible NO synthase (iNOS) expressed in the diaphragm during endotoxemia, participates in the development of muscular contractile failure. The aim of the present study was to investigate whether this deleterious action of NO was related to its effects on cellular oxidative pathways. Rats were inoculated with E. coli lipopolysaccharide (LPS) or sterile saline solution (controls) and studied at 3 and 6 h after inoculation. iNOS protein and activity could be detected in the rat diaphragm as early as 3 h after LPS, with a sustained steady-state concentration of 0.5 microM NO in the muscle associated with increased detection of hydrogen peroxide (H(2)O(2)). In vitro, the same NO concentration produced a marked increase in H(2)O(2) production by isolated control diaphragm mitochondria, thus reflecting a higher intramitochondrial concentration of nondiffusible superoxide anion (O(2)(-.)). In a similar way, whole diaphragmatic muscle and diaphragm mitochondria from endotoxemic rats showed a progressive increase in H(2)O(2) production associated with uncoupling and decreased phosphorylating capacity. Simultaneous with the maximal impairment in respiration (6 h after LPS), nitration of mitochondrial proteins (a peroxynitrite footprint) was detected and diaphragmatic force was reduced. Functional mitochondrial abnormalities, nitration of mitochondrial proteins, and the decrease in force were significantly attenuated by administration of the NOS inhibitor L-NMMA. These results show that increased and sustained NO levels lead to a consecutive formation of O(2)(-.) that reacts with NO to form peroxynitrite, which in turn impairs mitochondrial function, which probably contributes to the impairment of muscle contractility. during endotoxemia.

Risk factors for negative sputum acid-fast bacilli smears in pulmonary tuberculosis: results from Dakar, Senegal, a city with low HIV seroprevalence

SETTING

Two teaching hospitals in Dakar, Senegal, a West African country with a low prevalence of human immunodeficiency virus (HIV) infection.

OBJECTIVE

To determine whether patients with HIV-associated pulmonary tuberculosis have fewer acid-fast bacilli (AFB) in their sputum as assessed by routine microscopy, and to correlate the findings with systematically obtained clinical, radiographic and laboratory variables.

DESIGN

Prospective study from November 1995 to October 1996 of 450 consecutive patients diagnosed with pulmonary tuberculosis.

RESULTS

Tuberculosis was diagnosed in 380 patients (84.4%) by positive bacteriology, in 61 (13.6%) by a favorable response to anti-tuberculosis chemotherapy, and in nine (2.0%) by the presence of a miliary radiographic pattern. Forty (8.9%) patients were HIV-seropositive. AFB-negative smears were found in 14/40 (35.0%) of the HIV-seropositive patients with pulmonary tuberculosis compared with 71/410 (17.3%) of the seronegative patients (risk ratio [RR] = 2.02, 95% confidence interval [CI] 1.26-3.24, P = 0.01). Multivariate analysis revealed that AFB smear negativity was associated with absence of cavitation (P = 0.002), lack of cough (P = 0.005), the presence of HIV seropositivity (P = 0.02), a CD4+ cell count above 200/mm3 (P = 0.02), and age over 40 years (P = 0.03).

CONCLUSIONS

Compared with HIV-seronegative patients with pulmonary tuberculosis, seropositive patients in Dakar, Senegal, are more likely to have negative sputum-AFB smears. This phenomenon has now been observed in seven of eight sub-Saharan African countries with varying HIV seroprevalence from which reports are available.

[Rectal temperature trends during 24 hours in a hot climate with and without nutritional support]

A group of 22 young subjects staying in rest was studied in the aim to follow the nycthemeral evolution of the rectal temperature, according to two situations: 1) normal feeding, 2) absence of feeding. The use of drinking water was not limited. The experimentation was carried out in tropical area, Kédougou (Eastern Senegal), during a high period of temperature. The mean of day temperature was 38 degrees C and the night temperature, 22 degrees C. The skin and rectal temperature, the arterial pressure and the cardiac frequency were measured every three hours. The results showed a significant difference in the nycthemeral rythm of the rectal temperatures. The nocturnal temperatures were not different in the two conditions. We observed a significant elevation (delta = 0.31 +/- 0.18 degree C) of the diurne post prandial temperature. The results supported that the thermic modification observed during the experience were linked to the feed.

[Bacteriology of vulvo-vaginitis in pediatrics]

Fifty (50) samples of genital secretions are collected from young girls between 1983 and 1994 at Albert Royer Hospital (Dakar, Senegal), to research pathogenic strains. Each sample were studied by microscopic examination and culture in several media after enrichment. 70% of the samples are positive of specific agents (37.25%), particularly Candida albicans (19.6%). Neisseria gonorrhoeae was found among the elders. This retrospective study shows the rarity of specific agents of genital infections generally isolated among the adults. The authors were not able to research other agents as Chlamydia trachomatis or viruses.

[Effects of water deprivation on rectal and skin temperature and on performance in sustained muscular exercise in a hot climate]

This study was performed on 16 Senegal young soldiers well trained in physical activities. Experimentation was done in tropical zone in Kedougou (Oriental Senegal) during Scorching period if the year, diurnal-room temperature 34 degrees 9 average. The subject had to ride on a cyclo ergometer to a force corresponding to 75% maximum. The central cutaneous temperature, the provided force, and the cardiac frequence were measured at the end of the muscular's exercise. For each subject that effort's test was once in normal alimentation and the other one after 24 hours' hydric privation. We noticed a significant low of the provided power for having 75% of the maximal cardiac frequence, after half hours (30 mn) of exercise during the hydric restriction compared to normal alimentation. In other respects, a regular increase was observed of the rectal temperature in the course of the activity in any case. That rise was more important to subject in hydric restriction. On the other hand there wasn't any significant difference of the cutaneous temperatures in both situations. The hydric privation has caused a hypohydration in origin of the significant decrease of the performance even if they remain moderated.

[Bacteriological study of purulent nasopharyngitis in children in Senegal]

BACKGROUND

S pneumoniae, H influenzae and M catarrhalis are the main bacteria isolated from rhinopharynx in Europe. The purpose of this work was to study the frequency of potential pathogenic bacteria isolated from acute purulent rhinopharyngitis among children in Senegal.

POPULATION AND METHODS

Ninety-three children from one month to 7-years old suffering from purulent rhinopharyngitis were recruited from April 1 to July 1996. The withdrawal samples were taken from the cavum with a swab which was immediately immersed in an agar shipping medium. Bacteria's grouping and serotyping were made by immunoagglutination. A standard antibiogram was made for all isolates and furthermore the minimal inhibitory concentration (MIC) were determined for S pneumoniae.

RESULTS

Two hundred bacterial strains were isolated: S pneumoniae 28% (60% of the children), C group streptococci: 19% (41% of the children), H influenzae: 15.5% (33% of the children), S pyogenes: 9.5% (20% of the children), S aureus: 8% (17% of the children) and M catarrhalis: 6% (13% of the children). The other isolates were: B and D groups streptococci, P aeruginosa and Klebsiella spp. S pnuemoniae strains belonged to serogroups 6, 19 and 23. Only three strains of H influenzae were capsulated (serotype b). Infants aged from 6 to 18 months were the most affected. No resistance to penicillin was observed for S pneumoniae and S pyogenes. Ampicillin (81%) and chloramphenicol (96%) both inhibited the majority of H influenzae strains.

CONCLUSIONS

This descriptive bacterial epidemiology study of children's rhinopharynx's flora in Senegal allowed us to identify three major pathogenic germs: S pneumoniae, H influenzae and S pyogenes contributing to a better knowledge of these microorganisms' serotypes, biotypes and antibiotypes.

New branched-chain fatty acids from the Senegalese gorgonian Leptogorgia piccola (white and yellow morphs)

Fatty acids from total lipids of the gorgonian Leptogorgia piccola (white and yellow morphs), collected from the same area at two different periods with regard to the average water temperature, were studied. More than fifty fatty acids were identified as methyl esters and N-acyl pyrrolidides by gas chromatography and gas chromatography/mass spectrometry. Three new, branched-chain unsaturated fatty acids were identified in addition to the unusual 7-methyl-6-hexadecenoic acid, namely 10-methyl-6-hexadecenoic, 7,9-dimethyl-6-hexadecenoic, and 10-methyl-6,9-heptadecadienoic acids. Also 6,9-heptadecadienoic acid was identified. The fatty acid patterns of specimens harvested in colder waters were quite different from those harvested in warmer waters in that the former contained high amounts of methylene-interrupted polyunsaturated acids, including tetracosapolyenoic acids, especially 6,9,12,15,18-24:5 (up to 15.8% of the total acid mixture) and 6,9,12,15,18,21-24:6 (up to 5.3%). Arachidonic acid was, nevertheless, a major component in all the fatty acid mixtures studied (13.6-20.5%). Based on gas chromatography/Fourier transform infrared experiments, the double bonds were assigned the (Z) configuration. Several fatty aldehydes and their dimethyl acetals were also detected, of which the most abundant was octadecanal.

[Bacteriological study of purulent otitis media in children in CHU in the tropical zone]

BACKGROUND

Haemophilus influenzae and S pneumoniae are the most common causative agents of acute otitis media in Europe and the USA. This work aimed to identify the agents in Senegal and to study their sensitivity to antibiotics.

POPULATION AND METHODS

Two hundred and one patients, aged 0 to 15 years, with persistent middle-ear effusion, were included in this study from 1983 to 1993. Purulent samples aspirated from the external canal were analysed for bacteriology and sensitivity testing.

RESULTS

Eighty two percent of cultures were positive for Staphylococcus aureus (37%), Pseudomonas aeruginosa (25%), Proteus (18%) and Klebsiella (8%). Positive cultures were found mainly in children aged between 1 and 5 years. Amikacin and cefotaxim were the most active antibiotics against the majority of strains. Staphylococcus aureus was always resistant to penicillin.

CONCLUSIONS

Prevalence of Staphylococcus aureus as the causative agent of persistent middle-ear effusion may be explained by late examination. Its resistance to penicillin favors early administration of third generation cephalosporins or pristanimycin.

[Prevalence of Delta hepatitis in health workers in Dakar (Senegal)]

708 hospital workers in University Teaching Hospital of Dakar were tested to HBs antigen; among them 128 were positive and tested to Delta antibody, by ELISA Abbott kit. Seven (7) men and one woman were positive. However, the positivity of Delta antibody is neither linked to sex, nor to age of subjects. 87% of the Delta antibody carriers were found among the trainees, and 50% of them studied in the Odonto-Stomatology Institute.

[Bacteriology of neonatal septicemia in Dakar]

Between February 1983 and February 1991, 471 blood cultures from newborns with neonatal infection, aged from 0 to 30 days, admitted to the Pediatric Hospital Albert Royer, Dakar, were performed. In 141 (30.3 percent) cases, one bacterium was isolated. Three major causative organisms were identified: Klebsiella spp (28.6 percent), E. coli (19.5 percent) and S. aureus (17.4 percent). Altogether, we isolated 99 (69.2 percent) enterobacteria, 7 (4.8 percent) other Gram negative bacilli and 37 (25.8 percent) Gram positive cocci among which 25 S. aureus, 10 streptococci (7 group B, 2 group D, 1 group A and 2 pneumococci). The most efficient antibiotics were amikacin and third generation cephalosporins.