Enterococci are facultative anaerobic Gram-positive bacteria, immobile and non-encapsulated, present in the digestive tract of animals and humans [1] . Some species are useful in the manufacture of dairy products, playing a role in the conservation and bacteriological quality of food while maintaining their nutritional and organoleptic properties. But others are often opportunistic and cause infections in adults and newborns especially Enterococcus faecalis and Enterococcus faecium which rank among the leading causes of nosocomial bacteremia and urinary tract infections [2] [3] . They often persist on hospital surfaces due to their ability to withstand adverse environmental conditions (low or high temperatures, high pH, and high salinity). The global Enterococcus faecalis—Enterococcus faecium ratio is currently shifting towards Enterococcus faecium. The acquired antibiotic resistance traits of this latter species can explain this evolution [4] .

The advent of antibiotic therapy in the 1940s allowed a significant evolution in the management of infectious diseases. Unfortunately, antimicrobial resistance has quickly become a global health problem [5] . Enzymatic inhibition, reducing membrane permeability, modification of antibiotic targeted binding sites and the production of efflux pumps are some of the mechanisms used by organisms to fight against antibiotics. Some of the main reasons for antimicrobial resistance are self-medication, incorrect use of antibiotics (wrong dosage and prolonged use), lack of standards for health workers and misuse in animal husbandry [5] .

Enterococci present variable resistance levels to some antibiotics. This is the case for aminoglycosides, beta-lactams and cephalosporins [6] . In 2017, WHO ranked Enterococci among priority pathogens for research and development of new antibiotics. In America, a study carried out by Faron et al., in 2016 indicated that the prevalence of vancomycin-resistant Enterococci (VRE) over the past decade was increasing [7] . In 2015 Abamecha et al.; in Ethiopia evaluated the resistance profile of Enterococci and demonstrated that 36% of the isolated strains were resistant to ampicillin, 54.4% to streptomycin and 34.2% to gentamycin [8] . While in Algeria, Benzaid et al., in 2022 reported a prevalence of 7.81% of nosocomial infections due to Enterococcus faecalis [9] . In Cameroon, a study conducted in 2015 by Gonsu et al.; on the antibiotic sensitivity profile of Enterococci showed that 94% of Enterococcus faecalis strains were resistant to erythromycin, 59% to trimethoprim + sulfonamides and 53% to tetracycline. They stated that the majority of strains were isolated from 72% of hospitalized patients, and 27.58% of non-hospitalized patients [10] .

However, few studies have been carried out in Cameroon to fully understand the burden of antibiotic resistance as a result of Enterococci in hospital acquired infections. Therefore, the objective of our study was to determine the antibiotic resistance profile of Enterococcus faecalis and Enterococcus faecium isolates from urine and pleural fluid in two hospitals of Cameroon.

The current study highlights the significance of the fight against antibiotic resistance, contribute to the care of patients suffering from multi-resistant bacteria and reduce nosocomial infections. The study revealed a high frequency of Enterococcus faecium mostly encountered as compared to Enterococcus infection with significant resistance to 11 antibiotics.

The average age of the participants in the current study was 35 years given that the African population is mainly made up of young people. Furthermore, our participants were predominantly women (66.99%) than men (36.01%). This is explained by the fact that women are more exposed to urinary infections due to the anatomical particularities of the urinary system; their urethra is shorter, making it easier for bacteria to enter the bladder [11] .

The Enterococcus spp were isolated in 27.79% of our samples. This result is higher than the 8.44% found by Akhter et al. in Tunisia in 2014 in which they isolated Enterococci from urine only [12] . Enterococci ranks among the leading bacteria responsible for urinary tract infection [13] [14] .

In the current study, E. faecium predominates over E. faecalis (66.2%); these results are similar to those of Gonsu et al.; who also demonstrated the predominance of 52% of E. faecium [10] . Recent studies have demonstrated that the worldwide ratio of Enterococcus faecalis—Enterococcus faecium is changing in favor of E. faecium due to the Intrinsic and acquired antimicrobial resistance traits of this species [15] [16] .

The antibiotic susceptibility testing of the current study revealed of a strong resistance to penicillins, tetracyclines, and macrolides. This is similar to that of Muylaert and Mainil who reported this resistance to macrolides, tetracycline betalactams. Intrinsic resistance to beta lactams is maintained in Enterococci through the overproduction of penicillin binding proteins. Concerning aminoglycoside resistance, the low permeability of the well to the large aminoglycoside molecules could explain the moderate resistance [17] . Furthermore, 6.65% of Enterococcus spp isolates were resistant to Glycopeptide. Resistance to glycopeptides is mainly the result of the presence of resistance genes carried by plasmids. The most common being vanA, vanB and vanC [18] .

The univariate analysis of risk factors in our study allowed us to highlight the main factors linked to infection due to Enterococcus spp such as hospitalization (OR = 5.37; P-value = 0.00), hand hygiene (OR = 2.57; P-value = 0.01) and the specimen type (OR = 2.37; P-value = 0.01). Our results corroborate with a similar study carried out by Stucki et al. in Switzerland in 2014 [19] . These values could be explained on the one hand by the fact that when hygiene and environmental conditions are not favorable, the promiscuity of patients in hospital rooms favors transmissible infections; during their stay at the hospital, patients are exposed to bacteria through several sources including infected patients especially when hygiene rules are not respected [20] . On the other hand, the length of stay hospital is also a factor because the more a hospitalized person is bedridden, the more they are exposed to the risk of infections due to Enterococcus spp [21] . These factors were equally linked to glycopeptide resistant Enterococcus.

Our study revealed that the frequency of Enterococcus infection was 27.79% with Enterococcus faecium mostly encountered (66.2%). Significant resistance to penicillin (99.3% Ampicillin), macrolides (66.2% Erythromycin) and cyclines (85.2% Doxycycline) were observed. Equally, 6.65% of Enterococcus spp isolates were resistant to Glycopeptide.

Risk factors related to infection with Enterococcus spp were related to the type of health facility, urine specimen and hand hygiene practices while risk factors related to infection with Enterococcus spp were hospitalisation, health facility and hand hygiene being related to glycopeptide resistant Enterococcus.

Our thanks go to all those who contributed to this research study.

Authors declare no competing interests.

Conceptualization: CID; Project administration: CID, and AMA; Resources: CID, LPM, EMNM, NMN; Methodology: CID, FW, GYK, CSN, CPK, LPM, EMNM, NMN and AMA; Investigation: FW, GYK, CSN, CPK, LPM, EMNM, NMN, HKT, MJTT, and YVYM; software: CID, and CSN; Formal analysis: CSN and FW; Visualization: CID, and AMA; Writing-original draft: CID, FW, GYK, and CPK; Writing-review and editing: CID, FW, and CSN; Validation: CID, and AMA; Supervision: AMA; Data curation: CID. All authors have read and agreed to the published version of the manuscript.

Djuikoue, C.I., Wega, F., Kombeu, G.Y., Nana, C.S., Kiyang, C.P., Medzam, L.P., Makougoum, E.M.N., Nkuigoua, N.M., Tagne, H.K., Talokou, M.J.T., Mavoungou, Y.V.Y. and Agbor, A.M. (2024) Antibiotic Resistance Profile of Enterococcus faecalis and Enterococcus faecium Isolates from Urine and Pleural Fluid in Two Hospitals of Cameroon. Open Journal of Medical Microbiology, 14, 39-49. https://doi.org/10.4236/ojmm.2024.141004