Clinical and Bacteriological Profile of Infections in Sickle Cell Children in Two Referral Hospitals in Niamey, Niger ()
1. Introduction
Sickle cell disease is a cosmopolitan genetic disorder [1] [2] . In Africa, 500,000 children are born with the disease, and 60% to 80% die before age of five years due to a lack of early detection and adequate treatment [3] . Infections frequently punctuate the course of the disease, and are life-threatening for children, especially in resource-limited countries [1] . Their highest incidence is observed in the first years of life, and their frequency decreases with age, but the risk persists throughout life. Meningitis and septicemia are the most serious infections in children [3] . A better understanding of the mapping of infections encountered should enable us to improve management and envisage more appropriate preventive measures. This study aimed to determine the clinical profile and the ecology of bacteria found in infections among sickle-cell children admitted to two referral hospitals in Niamey.
2. Patients and Methods
2.1. Type, Period and Study Setting
A retrospective descriptive study was conducted from January 2018 to July 2020 (36 months) in the pediatric wards of Niamey National Hospital and Amirou Boubacar Diallo National Hospital, two referral hospitals in Niamey.
2.2. Study Population and Variables
All sickle-cell children (SS or SC electrophoretic profile) aged between one (1) to 15 years admitted to the corresponding departments for suspicion of bacterial infection were included. All usable records containing at least one bacterial culture (urine, stool or blood) were studied. Children’s socio-demographic characteristics, clinical signs and culture results were the studied variables.
2.3. Sampling Technique and Analysis Methods
Urine was collected per micturition on the first micturition in a sterile jar in the morning. Stools were also collected aseptically in a sterile jar fitted with a sampling spatula. Blood cultures were taken in the event of a febrile peak (≥38.5˚C) or hypothermia (≤36.5˚C) in culture media. All samples were taken in hospital, and then transported to the laboratory in no more than one hour for processing. Lumbar puncture was performed if patients had neurological signs. Bacteriological analysis was carried out using the appropriate culture media, using BactAlert (Reference 4700003 BTA3D60 BioMérieux).
2.4. Data Collection, Source and Statistical Analysis
A data extraction sheet was used to collect information from patients’ hospitalization records, and from the biology laboratory’s registers. Data were entered and analyzed using Epi-Info7 version 7.2.1 software. Results were expressed as numbers and percentages for children’s variables and bacteriological data.
2.5. Ethical Aspects
The study was approved by the Faculty of Health Sciences of Abdou Moumouni University of Niamey, and the management of both hospitals. Anonymity and medical confidentiality were respected.
3. Results
3.1. Characteristics of Children
Over 36 months, 350 children with sickle cell disease were admitted for suspected bacterial infection. Table 1 shows Children characteristics. The mean age was 10.9 months [6 months-14 years]. The sex ratio was 1.2. The SS electrophoretic profile was the most common (93.4%). Classical Expanded Program of Immunization (EPI) vaccination status (diphtheria, tetanus, pertussis, poliomyelitis, yellow fever, measles and pneumococcus) was up to date in 66% of patients. None had received vaccines outside the EPI. Fever was the most frequent reason for consultation (55.1%), followed by pallor (52.1%). C-reactive protein (more than 6 mg.L−1 was positive in 84.4% of cases, and hyperleukocytosis, defined as a white blood cell count above 20.000 cells/µL, was found in 96.4%. The diagnosis of infection was confirmed in 62 patients (17.7%). The most frequent diagnoses (Table 2) were bacterial gastroenteritis (24.2%), urinary tract infection (19.4%), pneumonia (19.4%) and acute osteomyelitis (9.7%).
3.2. Bacteriological Profile
Bacteriological results are shown in Table 3. Blood cultures were taken from 46 children, with 28.3% of positivity. The main germs isolated were Salmonella typhi (13.0%) and Escherichia coli (8.7%). Urine cytobacteriological examination (UCBE) was carried out in 99 patients, with 12.1% of positive results. Klebsiella spp (7.1%) and Escherichia coli (5.0%) were found. Fifty-one (51) coprocultures were requested, with 29.4% positive results. Salmonella typhi (23.5%) and Escherichia coli (5.9%) were isolated. Cytobacteriological examination of cerebrospinal fluid revealed one (1) case of Streptococcus pneumoniae. Ceftriaxone combined with gentamicin was used in 96.3% in the treatment. Progression was favorable in the majority of patients (99.4%). One (1) death resulting from complications of anemia was observed.
4. Discussion
Management of bacterial infections in sickle cell children should be based on probabilistic antibiotic therapy, considering to avoid progression to severe sepsis [1] [2] . Based on the observations of this study, the bacterial ecology in our context was similar to that usually reported in the literature. The limitations of this work were mainly related to the almost systematic prescription of antibiotics in hospitalized sickle cell patients, which probably increased the low culture positivity rate. In all cases, the incidence and severity of infections, and the context of limited resources, justify this therapeutic attitude.
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Table 1. Characteristics of children.
*UCBE: Urine cytobacteriological examination.
4.1. Characteristics of Children
The predominance of children under five years of age in this series has been reported by Diakité et al. [4] in Mali and Latoundji et al. [5] in Benin. Generally, the high susceptibility of sickle-cell patients to infection is well known, and the risk of infection is greatest in younger children, particularly infants [1] [2] . In addition to the physiological immaturity of the immune system in this age group, functional asplenia associated with abnormalities in immunoglobulins, leukocyte function and cell-mediated immunity could further weaken the means of infectious control in these children [6] [7] .
4.2. Bacteriology
Knowledge of the local bacterial ecology is essential for effective antibiotic prophylaxis and vaccination prevention programs. In this study, Salmonella typhi and Escherichia coli dominated the bacteriological profile. In the series by Douamba et al. in Burkina Faso, Streptococcus pneumoniae (35.5%) and Salmonella spp (33.3%) were more frequently reported [8] . The predominance of Streptococcus pneumoniae found by these authors can be explained by the fact that brocho-pneumonia being the most frequent diagnosis. Indeed, pneumonia in children with sickle cell disease is essentially due to Streptococcus pneumoniae [7] [9] [10] [11] [12] . The relatively high EPI vaccination coverage in our context, considers this bacterium, and the systematic antibiotic prophylaxis with oral penicillin in all sickle-cell children, could explain the low proportion of pneumococcal infections observed. Generally, invasive pneumococcal infections have been a major cause of morbidity and mortality in sickle cell patients, especially in precarious living conditions. These infections are often brutal and severe, making curative treatments often ineffective [13] . While preventive antibiotic therapy with penicillotherapy has proved effective, vaccination remains the principal means of control [14] . Salmonella typhi, found in coprocultures in this study, is more likely to be implicated in osteoarticular infections [15] . According to the authors, this could be explained by their high susceptibility to osteoarticular infections. What’s more, these infections are endemic in the context of poor living conditions [3] . However, effective prevention through vaccination has been available for many years. This should be offered systematically to all children with a tare, generally from the age of two for the polysaccharide vaccine, and six months for the conjugate vaccine [16] . Other studies have also reported the predominance of Escherichia coli and Klebsiella spp in urinary tract infections. The perineum is highly colonized by enterobacteria of digestive origin, in particular Escherichia coli. In addition, this bacterium possesses specific uropathogenicity factors, thus favoring these infections [17] [18] .
5. Conclusion
Bacterial ecology appears not different from that usually observed in sickle-cell children. Salmonella typhi and Escherichia coli predominate, mainly responsible for urinary tract and gastrointestinal infections. Prophylaxis must therefore take these results into account, particularly about Salmonella. Indeed, an immunization program should be set up for sickle cell children. It would also be necessary to strengthen diagnostic resources to enable a more complete mapping of pathogens, and to adapt preventive measures.