Seasonal variations in haematological and biochemical parameters of healthy Gambian adults: Retrospective study 2018-2022.

The objectives of this study were to determine the presence and effect of seasonal variations and provide insights into trend from 2018 to 2022 in a comprehensive set of routine haematological indices and biochemical measurements in Gambian adults with no known underlying health condition. We retrieved five years of data from an electronic database and analysed 493 full blood counts and 643 biochemical data from different individuals. In this study, we focused on data from individuals with no known underlying health condition who visited the clinical diagnostic laboratory for routine medical examinations or assessments.Our study found a positive association between seasonality (wet season as the reference) and Hb (HB: 0.014(0.015), P<0.05), White blood cells (WBC) (WBC: 0.243(0.163), p = 0.0014), and neutrophils (neutrophils: 0.271(0.131), P<0.05) with exception to red blood cells (RBC) (RBC: - 0.184(0.061), P< 0.003) that showed negative association. Despite the association, the seasonal effects on our derived reference intervals for haematological indices and biochemical measurements from wet season to dry season were not statistically significant (P>0.05). In addition, we observed in our heatmap result that some laboratory parameters, including HB, RBC, haematocrit (HCT), urea, liver enzymes, and potassium, showed seasonal variation patterns throughout the year, with median levels being normal to slightly low during the dry season and normal to high during the wet season. We also found no significant difference (P>0.05) among the median values for all parameters from 2018 to 2022. Additionally, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) parameters showed a consistent declining trend from 2018 to 2022. Our study found no seasonal effects on the derived reference intervals of haematological indices and biochemical measurements. However, we observed changes in patterns for certain parameters particularly HB, RBC, liver enzymes, and potassium based on seasonality.

Laboratory indices of hospitalized sickle cell disease patients, prevalence and antimicrobial susceptibility of pathogenic bacterial isolates at MRCG ward in the Gambia.

BACKGROUND: The aim of this study was to determine the prevalence of invasive bacterial infections and their antimicrobial resistance patterns in sickle cell disease (SCD) patients admitted at the Medical Research Council the Gambia (MRCG) Ward in the era of PCV and Hib vaccination in the Gambia. METHODS AND RESULTS: This study was conducted in the clinical laboratory department of MRCG. We retrospectively generated haematological, and blood culture data from our electronic medical records from 2015 to 2022 of SCD patients admitted to MRCG Ward. Of 380 SCD patients, blood culture was requested only for 159. Of the 159 admitted SCD, 11 patients had qualified positive blood cultures. Five different types of bacterial pathogens were isolated from these positive blood cultures: 4 Staphylococcus aureus, 3 Streptococcus pneumoniae, 2 Salmonella species, 1 Enterococcus species, and 1 Shigella boydii. No episode of bacteremia caused by Haemophilus influenzae type b was identified. The molecular serotyping of the Streptococcus pneumoniae isolates revealed non-vaccine serotypes 10 A, 12 F and 12 F. Penicillin resistance was recorded in two of the three Streptococcus pneumoniae. The Staphylococcus aureus isolates were penicillin resistant but cefoxitin sensitive, hence no methicillin (oxacillin) resistant Staphylococcus aureus was reported. Generally, the isolated pathogens were all sensitive to chloramphenicol, and vancomycin. The haematological indices were not significantly varied between SCD patients with and without microbiologically confirmed bacterial infection. CONCLUSION: Streptococcus pneumoniae and Staphylococcus aureus were the most common cause of bacteremia in these admitted SCD patients. The presence of non-typhoidal Salmonella and Shigella infection coupled with penicillin resistance should be considered during penicillin prophylaxis and empirical treatment regimens for SCD patients and future SCD management policies in the Gambia. The haematological parameters may not be reliable biomarkers in differentiating bacterial from non-bacterial infections in SCD patients.

Association between functional antibody against Group B Streptococcus and maternal and infant colonization in a Gambian cohort.

BACKGROUND: Vertical transmission of Group B Streptococcus (GBS) is a prerequisite for early-onset disease and a consequence of maternal GBS colonization. Disease protection is associated with maternally-derived anti-GBS antibody. Using a novel antibody-mediated C3b/iC3b deposition flow cytometry assay which correlates with opsonic killing we developed a model to assess the impact of maternally-derived functional anti-GBS antibody on infant GBS colonization from birth to day 60-89 of life. METHODS: Rectovaginal swabs and cord blood (birth) and infant nasopharyngeal/rectal swabs (birth, day 6 and day 60-89) were obtained from 750 mother/infant pairs. Antibody-mediated C3b/iC3b deposition with cord and infant sera was measured by flow cytometry. RESULTS: We established that as maternally-derived anti-GBS functional antibody increases, infant colonization decreases at birth and up to three months of life, the critical time window for the development of GBS disease. Further, we observed a serotype (ST)-dependent threshold above which no infant was colonized at birth. Functional antibody above the upper 95th confidence interval for the geometric mean concentration was associated with absence of infant GBS colonization at birth for STII (p<0.001), STIII (p=0.01) and STV (p<0.001). Increased functional antibody was also associated with clearance of GBS between birth and day 60-89. CONCLUSIONS: Higher concentrations of maternally-derived antibody-mediated complement deposition are associated with a decreased risk of GBS colonization in infants up to day 60-89 of life. Our findings are of relevance to establish thresholds for protection following vaccination of pregnant women with future GBS vaccines.