Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-Ec) poses a significant public health concern due to its widespread prevalence and resistance to multiple antibiotics. This study aimed to assess the prevalence, resistance profile, and carriage of ESBL-encoding genes in ESBL-Ec isolates from broilers in two markets of Dakar, Senegal. Sampling over a one-year period revealed that 61.7% of broilers carried ESBL-Ec in their cecum. Antibiotic susceptibility testing of 186 ESBL-Ec isolates showed high resistance to β-lactam antibiotics, including ampicillin, ticarcillin, and third-generation cephalosporins. Notably, all isolates were susceptible to imipenem. Multidrug resistance was frequent, with 91.4% of the isolates displaying this phenotype. Comparison between the two markets revealed variations in resistance to quinolones. PCR analysis detected bla_CTX-M genes in all isolates, with bla_CTX-M-1 being the most prevalent subgroup. Additionally, bla_TEM and bla_OXA genes were found in 26.3% and 2.7% of isolates, respectively, while no bla_SHV genes were detected. Combinations of ESBL genes were common, with bla_CTX-M15-bla_TEM being the most frequent. These findings highlight the widespread prevalence of ESBL-Ec in broilers from Dakar markets, indicating a potential risk of transmission to humans through the food chain. Effective surveillance and intervention strategies are crucial to mitigate the spread of antimicrobial resistance in humans and animals.

Background: Virulent and resistant Klebsiella pneumoniae strains are considered as one of the most significant causes of healthcare-associated infections (HAIs). The aim of this study was to investigate the phenotypic and genotypic factors of antibiotic resistance and virulence factors of ESBL K. pneumoniae strains isolated from healthcare-associated infections (HAIs) in Dakar, Senegal. Methods: Twenty-eight strains of K. pneumoniae isolated from HAIs were collected from 2018 to 2021 in 2 main hospitals in Dakar. Antibiotic susceptibility and molecular characterization were studied using disk diffusion by the Kirby-Bauer method and PCR, respectively. Virulence factors were also determined by PCR. Results: These ESBL K. pneumoniae isolates showed high resistance to antibiotics such as β-lactams, aminoglycosides, cyclins, fluoroquinolones and trimethoprim-sulfamethoxazole. Among these strains, ten (10) were resistant to carbapenem and cefoxitin (17.8%, n=5), chloramphenicol (25%, n=7) and fosfomycin (28.5%, n=8) considered as the most active antibiotics against ESBL-KP isolates. Eighteen (18) strains were considered as MDR and ten (10) strains as XDR. For the genes associated to phenotypic resistance, β-lactams resistance was conferred through blaSHV (24/28), blaTEM (20/28) and mainly by blaCTX-M. All strains carried the blaCTX-M15 gene. OXA-48 (6/28) gene was found responsible for carbapenem resistance and other genes like IMP, VIM, NDM, OXA-23 were not detected. Plasmids-mediated resistance genes qnrB (16/28), qnrS (11/28) and aac(6’)-Ib (21/28), were mostly responsible for resistance to fluoroquinolones and aminoglycosides. Also 3 of 6 virulence genes searched that are the most associated to the pathogenicity of Klebsiella pneumoniae were found on these strains with uge (19/28), mrKD (21/28) and fyuA (13/28). Conclusion: The ESBL K. pneumoniae strains isolated in this study showed a high prevalence of antibiotic resistance and virulence genes The combination of these factors poses a potential risk for infections that could be highly virulent and difficult to treat. These findings demonstrated the importance of closely monitoring the resistance patterns of K. pneumoniae in hospitals seetings and emphasize the need to monitor effective antibiotic treatments for K. pneumoniae infections. Aditionnally, the scarcity of available data on HAIs, especially the prevalence of Multidrug resistance bacteria and virulence factors associated with these HAIs in Senegal, further emphasizes the significance of implementing surveillance programs to better know their prevalence, impact on patient health and on length of hospital stays.

Two bacteriophages (phages) of Klebsiella pneumoniae were isolated from sewage water collected from Dakar, Senegal. Phage vKpIN17 belongs to the Przondovirus genus within the Autographiviridae family, with double-stranded DNA genomes, whereas vKpIN18 belongs to the Webervirus genus of the Drexlerviridae family.

Extra-Intestinal Pathogenic Escherichia coli (ExPEC) is a predominant Gram-negative bacterial pathogen and is responsible of several diseases including Urinary Tract Infections (UTI), nosocomial pneumonia, and neonatal meningitis. ExPEC isolates are often multidrug resistant and clones producing Extended-Spectrum Beta-Lactamases (ESBL) are increasingly reported all over the world.

Klebsiella pneumoniae (K. pneumoniae) isolates are often multidrug-resistant (MDR) and clones producing extended-spectrum beta-lactamases (ESBL) are increasingly reported all over the world. This study aimed to determine drug-susceptibility profiles and characterize ESBL genes in clinical strains of K. pneumoniae in an university teaching hospital of Dakar. Sixty-six ESBL-producing K. pneumoniae strains were selected for this study and subjected to the Kirby-Bauer disk diffusion method and standard polymerase chain reaction (PCR) for the screening of major ESBL genes (blaCTX-M, blaCTX-M-9, blaCTX-M-15, blaCTX-M-25, blaOXA-1, blaTEM, blaSHV). All isolates were resistant to ampicillin, ticarcillin, amoxicillin/clavulanic acid combination, cefalotin, cefotaxime, ceftazidime and cefepime, while 60% (40/66) of them were resistant to fosfomycin. Amikacin, ertapenem and imipenem remained effective with respective sensitivity rate of 77.3% (51/66), 75.8% (50/66) and 100% (66/66). blaCTX-M (64/66; 97%) with its variant blaCTX-M-15 (63/66; 95.5%) were the most prevalent ESBL genes; followed by blaTEM (58/66; 87.9%), blaOXA-1 (47/66; 71.2%) and blaSHV (31/66; 47%). Sixty-four isolates out of 66 (97%) of isolates carried at least 2 ESBL genes and the most prevalent ESBL gene combinations were (blaCTX-M-15 + blaOXA-1 + blaTEM) (24/66; 36.4%) and (blaCTX-M-15 + blaTEM + blaOXA-1 + blaSHV) (18/66; 27.3%). Cephalosporins, quinolones and aminoglycosides (except amikacin) would no longer be recommended as first-line therapy in Enterobacteriaceae infections in Dakar. CTX-M-15-type ESBL seems to be predominant ESBL in K. pneumoniae isolates in Dakar. Amikacin would be an alternative molecule for the treatment of MDR ESBL-producing-K. pneumoniae infections. Whole-genome sequencing of these isolates could provide additional and in-depth informations.

Bacterial virulence is a key factor determining the outcome of each bacterial infection, and virulent bacteria are often associated with high-risk infections. Thus, this study aimed to screen for virulence genes and evaluate the in vitro biofilm formation capacity of multidrug-resistant Escherichia coli isolated in Dakar. For the 16 virulence genes identified by standard polymerase chain reaction (PCR), all 78 ExPEC isolates carried at least four virulence genes. The prevalence of virulence genes was as follows: adhesin genes fimH (98.7%), mrkD (98.7%), papC (46.2%), afaC (9%), and sfa/focDE (1.3%); iron acquisition system genes entB (98.7%), fepA (98.7%), ybtS (93.6%), fyuA (91%), iucA (91%), iucB (91%), iutA (34.6), iroB (6.4%), iroN (6.4%), and toxin genes hlyA (10.3%) and cnf (1 & 2) (10.3%). Seventy-five of the 78 isolates (96.2%) carried at least two adhesin genes and two iron capture system genes. Evaluation of the biofilm formation capacity revealed that all (29/29) hospital-acquired isolates were biofilm producers with (6/29; 20.7%) strong biofilm producers, (15/29; 51.7%) moderate biofilm producers and (8/29; 27.6%) weak biofilm producers. Hospital-acquired isolates carrying papC had a greater biofilm formation capacity than those lacking papC (p < 0.001). The deepening of this type of study on bacterial virulence and hospital bacterial biofilms could lead to improvements in infection investigation, prevention, and therapeutic protocols.