Urogenital Tract Infections (UTIs) are currently among the most common reasons for medical consultation and represent a major global public health issue, both in community and hospital settings [1] . Enterobacteriaceae are ubiquitous Gram-negative bacilli and opportunistic pathogens frequently implicated in UTIs [2] . Due to their wide distribution and ability to acquire virulence factors and antibiotic resistance mechanisms, they are isolated in both community and healthcare settings [3] . The emergence and dissemination of antibiotic-resistant Enterobacteriaceae represent a major global public health threat, compromising treatment efficacy and increasing infection-associated morbidity and mortality [4] . Over the past decades, the emergence and spread of Enterobacteriaceae resistant to last-resort antibiotics such as carbapenems have posed a growing challenge to treatment efficacy [3] . Carbapenems, as broad-spectrum β-lactams, are often considered essential agents for the treatment of severe infections caused by multidrug-resistant bacteria [4] . However, the appearance of resistance mechanisms, mainly through carbapenemase production, poses a significant therapeutic challenge, limiting effective treatment options and increasing the risk of therapeutic failure and resistance dissemination via genetic transfer to other bacterial species. Carbapenem-resistant Enterobacteriaceae often produce enzymes that hydrolyze carbapenems, known as carbapenemases [5] . Among these enzymes, Metallo-β-Lactamases (MBLs) are particularly important due to their ability to inactivate a wide range of β-lactams, including carbapenems, and their resistance to clinically available β-lactamase inhibitors, except for avibactam, which does not inhibit MBLs [6] . In Africa, several studies have investigated carbapenem resistance in Enterobacteriaceae, including work by Habibou et al. [7] in Senegal, Ramkisson et al. [8] in South Africa, Garba et al. [9] in Burkina Faso, Ragueh et al. [10] in Djibouti, Dos et al. [11] in Gabon, and more recently by Hamidou et al. [12] in Niger and Benin. In the Republic of Congo, bacterial infectious diseases remain a major concern, further compounded by the absence of national surveillance on antibiotic resistance. The literature review revealed several studies on β-lactamase production in bacteria isolated from wound infections and on the transmission of β-lactam resistance among Enterobacteriaceae from mothers to children in Brazzaville [13] [14] . Mpelle et al. [15] reported the first detection of TEM, CTX-M, SHV, and OXA-48 β-lactamases in Escherichia coli in the Republic of Congo. Although Makaya et al. [16] (2022) studied MBL- and ESBL-producing Enterobacteriaceae in Brazzaville, epidemiological data specific to carbapenem resistance in Enterobacteriaceae from urinary infections remain insufficient. Therefore, it is crucial to improve understanding of carbapenem resistance profiles and MBL production prevalence among Enterobacteriaceae isolated from urogenital tract infections. This work contributes to strengthening strategies for surveillance, prevention, and management of urinary tract infections.

Antibiotic resistance among Enterobacteriaceae, particularly to carbapenems, represents a major public health challenge. This issue is critical both in industrialized countries and in developing countries, where self-medication and the uncontrolled sale of antibiotics outside legal frameworks are common. The main objective of this study was to describe the carbapenem resistance profile of Enterobacteriaceae strains isolated from urogenital tract infections at the National Public Health Laboratory. These strains were obtained from urine and vaginal swab samples. A total of 123 strains, distributed across five genera of Enterobacteriaceae, were isolated and identified. The distribution of the 123 strains according to sample type showed that urine was the specimen from which Enterobacteriaceae were most frequently isolated. These results are consistent with those obtained by Al-Mayahie et al. [23] , who reported urine as the most common sample type in hospitals in Iraq. In contrast, our results are higher than those reported by Alsamarai and Ali [24] in Kirkuk, Iraq, where only 41.6% of urine samples were culture-positive. The predominance of Enterobacteriaceae in urine samples in our study may be explained by the larger sample size of urine specimens compared to vaginal swabs. Bacterial identification revealed 12 different species, with E. coli being the most predominant, accounting for 35% of isolates. This finding is comparable to Moyen et al. [14] , who reported a predominance of E. coli (36%) in studies of β-lactam resistance transmission among mothers and children in the Republic of Congo. Similarly, Goro [25] reported comparable results in Bamako. The predominance of E. coli in these samples can be explained by its role as a normal component of the intestinal microbiota. Although generally harmless, uropathogenic strains of E. coli can cause urinary and extra-intestinal infections, possessing virulence factors, including adhesins, that allow colonization of the urinary epithelium and resistance to clearance during bladder voiding [3] .

The antibiotic susceptibility study revealed significant and variable resistance depending on the tested carbapenem. The highest resistance was observed for doripenem (66.67%), followed by imipenem (48.78%). Ertapenem was the most active molecule, with a resistance rate of 20.32%. These results are consistent with previous studies. For example, in Latin America, Costa et al. [26] reported 100% resistance to carbapenems (imipenem, meropenem, and ertapenem). Similar results were obtained in Tunisia by Ben et al. [27] , who reported a resistance rate of 55.8% to imipenem.

However, our results differ from those of Moyen et al. [13] , who studied β-lactam activity and β-lactamase production in bacteria isolated from wound infections in Brazzaville, Congo, where strains were more sensitive to imipenem (resistance rate 10.82%). Ya-Ting et al. [28] in Taiwan region reported resistance rates of 95.5%, 74.26%, 61.6%, and 96.2% for the four tested antibiotics. Makaya et al. [3] reported 68.8% resistance to imipenem in E. coli in Brazzaville. Rodríguez et al. [29] observed 100% resistance to imipenem and 98% resistance to meropenem and doripenem in Colombia. In our study, ertapenem was highly effective against all tested strains, contrasting with Ben et al. [27] , who reported 100% resistance to ertapenem. Differences in resistance may be attributed to temporal evolution, geographic location, antibiotic selection pressure, consumption patterns, and genetic transfer mechanisms.

Overall, the studied strains exhibited simultaneous resistance to multiple carbapenems. E. coli, along with other species, showed resistance to three carbapenem disks. These results are consistent with Moyen et al. [14] , who demonstrated β-lactam resistance transmission among Enterobacteriaceae between mothers and children in Brazzaville. In that study, E. coli and K. oxytoca showed 30% resistance to ertapenem, while K. oxytoca strains were fully susceptible to imipenem compared to 30% resistance in E. coli. The observed carbapenem resistance rates are concerning, as carbapenems constitute the last line of defense against bacterial infections. The predominance and broad-spectrum resistance of E. coli pose a serious public health threat, undermining the effectiveness of available antibiotics. This may result from selection pressure due to the excessive use of antibiotics in hospital and community settings, as well as plasmid-mediated horizontal transfer of resistance genes [30] . Similar observations were made by Habibou et al. [7] in Senegal, reporting a prevalence of 60.83%. All genera studied, Enterobacter, Klebsiella, Proteus, E. coli, and Citrobacter—showed resistance to the tested carbapenems. Mellouli et al. [31] reported similar findings in Tunisia. Abera et al. [32] observed low resistance rates in E. coli and K. pneumoniae producing ESBLs.

Carbapenem resistance can result from the selection of resistant bacteria favored by frequent use of these antibiotics in empirical treatment of severe nosocomial infections [33] . Literature data indicate that mechanical ventilation and treatment with carbapenems, alone or in combination with vancomycin, are major risk factors for acquiring imipenem resistance [34] . Resistance mechanisms may include non-enzymatic processes such as loss of OprD porin, active efflux systems (MexAB), or production of carbapenemases of the IMP and VIM types [35] .

To contextualize the results of our study on carbapenem resistance in our institution, it is relevant to compare them with the global data provided by the 2023 GLASS report of the World Health Organization (WHO). This report reveals that carbapenem resistance in Escherichia coli and Klebsiella pneumoniae remains high in many regions of the world, particularly in Asia, Africa, and Latin America [36] . This situation is mainly attributed to the spread of certain carbapenem resistance genes, such as KPC and NDM, as well as to person-to-person transmission within healthcare facilities [37] . Moreover, socio-economic factors, such as limited access to healthcare and the overuse of antibiotics, contribute to this alarming trend [36] . In our local context, these global data confirm that carbapenem resistance is a major public health issue, especially in developing countries. The results of our study, showing a high prevalence of carbapenem resistance in our institution, therefore fit within a worrisome global context. It is imperative to strengthen surveillance, prevention, and infection control strategies to effectively combat this emerging threat [37] .

In this study, all imipenem-resistant strains produced Metallo-β-Lactamases (MBLs), representing a 100% rate. This is higher than the 78.25% reported in India by Debasrita et al. [38] . These results differ from those of Makaya et al. [3] in Brazzaville, where 16.66% of strains were MBL producers. Gba et al. [39] in Côte d’Ivoire reported 78.6% of imipenem-resistant P. aeruginosa producing MBLs. In this study, 40% of E. coli produced MBLs in the presence of meropenem, lower than the 86.61% reported by Nu et al. [40] in Pakistan. Genetic variability among strains may explain these differences. A recent study in Morocco (2019 - 2023) found that all carbapenem-resistant Enterobacteriaceae (n = 74) produced MBLs, with bla_NDM predominating (83.78%), often associated with bla_OXA-48 [41] , similar to our findings. According to the international ATLAS program (2018 - 2020), nearly 50% of carbapenem-resistant Enterobacteriaceae in Africa and the Middle East carried MBLs [42] . A systematic review of 39 studies (2013 - May 2023) reported MBL-producing strain prevalence ranging from 6.8% to 100%, particularly high in Southern Europe and Asia [43] . Among MBL-producing strains, E. coli was the most prevalent, with 100% producing MBLs in the presence of imipenem, exceeding the 36.1% reported by Mudathir et al. [44] in Khartoum, Sudan. The combined test for the detection of Metallo-β-Lactamases (MBLs) using meropenem was limited to E. coli and Enterobacter aerogenes because these species are the main Enterobacteriaceae in which MBL production represents a frequent and clinically relevant mechanism of carbapenem resistance. Moreover, the interpretation criteria and reliability of the meropenem + EDTA combined test have been better validated for these Enterobacteriaceae in the CASFM/EUCAST recommendations, unlike other species in which alternative mechanisms (porin loss, AmpC overproduction, or production of KPC or OXA-48) may also contribute to resistance [22] .

This study presents certain limitations that should be acknowledged. First, its monocentric nature limits the generalization of the results to other healthcare facilities in Brazzaville and in other departments. Second, the short duration of the investigation does not allow conclusions to be drawn regarding the temporal dynamics of carbapenem resistance. Finally, the absence of molecular confirmation of the genes encoding Metallo-β-Lactamases (MBLs) prevents the precise identification of the enzyme types involved and the assessment of their genetic distribution among the isolates studied.

This study aimed to establish the carbapenem resistance profile of Enterobacteriaceae strains isolated from urogenital tract infections at the National Public Health Laboratory. A total of 123 strains were isolated from various biological samples, comprising five bacterial genera: Escherichia, Klebsiella, Enterobacter, Citrobacter, and Proteus, representing 10 species. E. coli was the most dominant species. The majority of strains were isolated from urine. The results show that the studied strains exhibited resistance to the tested carbapenems: 66.67% to doripenem, 48.78% to imipenem, 30.08% to meropenem, and 20.32% to ertapenem. Simultaneous resistance to imipenem, meropenem, and doripenem was observed. Significant differences in bacterial resistance among strains were noted for imipenem, meropenem, doripenem, and ertapenem. All imipenem-resistant strains produced MBLs, while only E. coli and Enterobacter aerogenes produced MBLs in the presence of meropenem. However, meropenem and ertapenem should be used as first-line agents for the treatment of infections caused by these bacterial genera.