High Mortality Rates and Antimicrobial Resistance in Children with Invasive Bacterial Infections in a Tertiary Care Facility in West Africa
Authors: Cherukumilli Sumanth , Still William , Tapia Milagritos D , Kotloff Karen L 
Published: October 2024

Abstract

Background
Childhood data on infection mortality and antimicrobial resistance in Sub-Saharan Africa are emerging but remain limited. The University of Maryland Center for Vaccine Development (CVD) and CVD-Mali have been conducting a prospective observational study at L’Hopital Gabriel Toure (HGT), a referral hospital in Bamako, Mali, since 2002 to identify causes of invasive bacterial infections (IBI) in children. These data have been used to initiate vaccination programs to decrease the burden of Haemophilus influenzae type b and Streptococcus pneumoniae. Additional demographic and antimicrobial susceptibility data have been collected since 2021, allowing for more detailed resistance and mortality analyses.

Methods
All children presenting to HGT are screened. Children ages 0-15 years with temperature of at least 39 degrees Celsius and/or suspicion of IBI are eligible. Eligible children have blood cultures collected with additional site-specific cultures when focal infection is suspected. Cultures are performed using the Bactec system; when positive, Gram staining, sub-culturing, and antimicrobial susceptibility testing (by disk diffusion using standard methods) are performed. Organisms thought to be contaminants are excluded. American type culture collection strains are utilized for quality control.

Results
Between 1/14/2021 and 9/14/2023, 28703 patients were screened. 2156 patients were included. 212 patients (10%) had 235 pathogens isolated. Gram positive organisms were most frequently isolated (N=112), followed by Gram negative Enterobacterales (N=81), non-Enterobacterales Gram negatives (N=36), and yeast (N=6). Staphylococcus aureus was the most frequently isolated Gram positive organism (59 bloodstream isolates, 2 joint isolates, 2 subcutaneous isolates) followed by S.pneumoniae (10 bloodstream isolates, 17 cerebrospinal fluid isolates, 1 joint isolate) and Enterococcus species (16 bloodstream isolates). Klebsiella pneumoniae (28 bloodstream isolates, 2 cerebrospinal fluid isolates) and Escherichia coli (18 bloodstream isolates, 3 cerebrospinal fluid isolates, 2 subcutaneous isolates) were the most frequently isolated Gram negative Enterobacterales, with Pseudomonas species most common among non-Enterobacterales Gram negative organisms (16 bloodstream isolates, 1 cerebrospinal fluid isolate). Mortality rates in both culture-positive and culture-negative patients were high (52% and 28%, respectively), with greater than 50% of deaths occurring within 48 hours in both groups. 88% of Gram negative Enterobacterales were ceftriaxone resistant or intermediate, with 56% ciprofloxacin resistant or intermediate; 55% of isolates were resistant or intermediate to both. 71% of isolates were gentamicin resistant. Imipenem resistance remained low, with 91% of isolates retaining sensitivity. 24% of S. aureus isolates were oxacillin resistant and 34% of isolates were resistant or intermediate to trimethoprim/sulfamethoxazole. 100% of S. aureus isolates tested (14/60) retained sensitivity to clindamycin. Only 54% of pneumococcal isolates had positive oxacillin screens, implying frequent penicillin resistance, and only 60% of enterococcal species were ampicillin sensitive, although 92% retained vancomycin sensitivity.

Conclusion
We found higher mortality rates in our study than in similar studies; the contribution of issues such as limited access to advanced supportive care and delay in presentation is an area for further study. The high frequency of multidrug-resistant organisms is alarming, suggesting an urgent need to investigate underlying contributing factors, increase access to affordable broad-spectrum antibiotics, and create robust antimicrobial stewardship programs.