TITLE:
Bloodstream Infections Caused by Klebsiella-Enterobacter-Serratia Group Enterobacterales at Dalal Jamm National Teaching Hospital (Dakar, Senegal) in 2024: Resistance Profiles and β-Lactam Resistance Phenotypes
AUTHORS:
Awa Ba Diallo, Elhadji Bambo Diakhaby, Harouna Diallo, Fahamia Cheha, Djibril Diop, Fatou Edwige Sall, Mariama Diallo, Omar Gueye, Alioune Tine, Adja Tacko Mane Diallo, Fatou Diagne, Habsa Diagne, Awa Soumare, Dieynaba Barry, Roughyatou Ka, Ndeye Coumba Toure Kane, Makhtar Camara
KEYWORDS:
Bloodstream Infection, Blood Culture, Klebsiella pneumoniae, Enterobacter, Serratia, Extended-Spectrum β-Lactamase, Carbapenems, MDR, Senegal
JOURNAL NAME:
Advances in Microbiology,
Vol.16 No.10,
September
30,
2026
ABSTRACT: Background: Enterobacterales of the Klebsiella-Enterobacter-Serratia (KES) group are among the leading causes of healthcare-associated bloodstream infections and concentrate resistance mechanisms that compromise empirical therapy. Blood culture-based data from Senegal remain scarce. We aimed to describe the frequency, susceptibility profiles and β-lactam resistance phenotypes of KES-group bloodstream infections at Dalal Jamm National Teaching Hospital. Methods: We conducted a retrospective descriptive study of all blood cultures processed in the Bacteriology-Virology laboratory of Dalal Jamm National Teaching Hospital between January and December 2024. The unit of microbiological analysis was the isolate; the unit of clinical description was the blood culture episode, defined as all bottles drawn from one patient within a 14-day window. Isolates were identified using API 20E strips and the Vitek 2 system; antimicrobial susceptibility testing was performed on Vitek 2 and interpreted according to CA-SFM/EUCAST breakpoints. Non-susceptibility combined the intermediate and resistant categories and is reported both by individual agent and by class. β-lactam resistance phenotypes were inferred from antibiogram profiles using a pre-specified algorithm that required a cefoxitin result; isolates without one were reported as not classifiable. Multidrug resistance was defined according to Magiorakos et al., after exclusion of species-specific intrinsic resistance. Results: Of 1844 blood cultures processed, 694 (37.6%) were positive and 589 isolates were considered significant after exclusion of 105 contaminants. Gram-negative bacilli accounted for 386 isolates (65.5%), of which 117 belonged to the KES group, representing 30.3% of Gram-negative bacilli and 19.9% of all significant isolates. Four isolates had no analysable antibiogram, leaving 113 isolates recovered from 110 blood culture episodes in at least 103 patients. Enterobacter spp. predominated (n = 53; 46.9%), closely followed by Klebsiella pneumoniae (n = 51; 45.1%) and then Serratia spp. (n = 9; 8.0%); only 10 of the 53 Enterobacter isolates (18.9%) carried a species-level identification. Paediatric units (neonatology, general paediatrics and paediatric oncology) accounted for 39.1% of episodes, ahead of the intensive care unit (14.5%) and clinical haematology (12.7%); 40.9% of episodes concerned children aged 10 years or younger. Median time to positivity was 1 day (IQR 1 - 2). Non-susceptibility to third-generation cephalosporins reached 94.1% in K. pneumoniae, 66.0% in Enterobacter spp. and 33.3% in Serratia spp. Carbapenem non-susceptibility was detected in 21 of 108 isolates tested (19.4%). Class-level aminoglycoside non-susceptibility (69.4% in K. pneumoniae) concealed a marked within-class divergence: amikacin was active against all 28 K. pneumoniae isolates tested (0% non-susceptible), and only 4 of 31 Enterobacter isolates were non-susceptible (12.9%), whereas gentamicin and tobramycin were non-susceptible in 58% - 75%. An ESBL-compatible phenotype was retained in 18 K. pneumoniae (35.3%) and 4 Enterobacter isolates (7.5%), with a further 35.3% and 20.8% respectively not classifiable because cefoxitin had not been tested. Multidrug resistance affected 94.1% of K. pneumoniae, 69.8% of Enterobacter spp. and 22.2% of Serratia spp. Conclusion: KES-group bloodstream infections are frequent at Dalal Jamm hospital, concentrate in paediatric and critical care units, and are dominated by multidrug-resistant isolates. The observed level of resistance to third-generation cephalosporins makes their empirical use inappropriate in this hospital, while the preserved activity of amikacin identifies a carbapenem-sparing option that deserves formal evaluation. The emergence of carbapenem non-susceptible isolates calls for a coordinated strengthening of microbiological surveillance, infection prevention and control, and antimicrobial stewardship, together with routine cefoxitin testing and molecular confirmation of resistance mechanisms.