Isolation and Characterization of Environmental Extended Spectrum ß-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae from Ouagadougou, Burkina Faso.

Antimicrobial resistance (AMR) is a global public health threat. Quality data are needed to address the rise of multidrug-resistant clones, particularly in sub-Saharan Africa. In this study, we analysed the prevalence, antimicrobial resistance profile, and presence of genes encoding extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-Ec) and Klebsiella pneumoniae (ESBL-Kp) in environmental samples from Ouagadougou, Burkina Faso. Of 264 samples collected, 95 (36%) and 74 (28%) contained ESBL-Kp and ESBL-Ec, respectively. ESBL-Kp was more prevalent in runoff water and in treated and untreated wastewater, while ESBL-Ec was more prevalent in manure. Interestingly, wastewater treatment did not significantly reduce the recovery of ESBL bacteria. As expected, resistance to third- and fourth-generation cephalosporins was predominant, and rare for second generation cefoxitin. Interestingly, all the isolates from treated wastewater were susceptible to ampicillin and piperacillin, while all the other clones were resistant to these antibiotics. Regarding the ESBL-encoding genes, the blaCTX-M family was the most abundant, with the blaCTX-M1 subfamily being the most prevalent. Carriage of combinations of ESBL genes was common, with the majority of the isolates harbouring 2-4 different genes. This study highlights the need for active surveillance to manage the risk of exposure to ESBL bacteria in Burkina Faso.

Trends in epidemiology and risk factors of opportunistic infections in kidney transplant recipients between 2004 and 2017.

BACKGROUND: While opportunistic infections are a frequent and challenging problem in kidney transplant recipients, their long-term epidemiology remains hardly known. METHODS: Opportunistic infections were recorded in 1144 recipients transplanted in our center between 2004 and 2015. Incidence rates and baseline risk factors were determined using joint frailty models. RESULTS: After a median follow-up of 5.6 years, 544 opportunistic infections occurred in 373/1144 (33%) patients, dominated by viral infections (396/544, 72%), especially cytomegalovirus (CMV) syndromes and diseases (213/544, 39%). One-third of the infected patients experienced at least two opportunistic infections. The incidence of opportunistic infections was 10 times higher during the first year post-transplantation than after that (34.7 infections for 100 patient-years vs 3.64). Opportunistic infections associated with the age of the donor (P = .032), the age of the recipient (P = .049), the CMV serostatus (P < 10-6), a higher class II HLA mismatch (P = .032) and an induction treatment including rabbit anti-thymocyte globulins (P = .026). Repeated opportunistic infections associated with each other (P < 10-6) and with renal death (P < 10-6). CONCLUSION: Opportunistic infections occur with a two-period incidence pattern and many susceptible patients suffer from repeated episodes. This knowledge may help tailor new prevention and follow-up strategies to reduce the burden of opportunistic infections and their impact on transplantation outcome.

Detection and Characterization of Carbapenemase-Producing Escherichia coli and Klebsiella pneumoniae from Hospital Effluents of Ouagadougou, Burkina Faso.

Hospital wastewater is a recognized reservoir for resistant Gram-negative bacteria. This study aimed to screen for carbapenemase-producing Escherichia coli and Klebsiella pneumoniae and their resistance determinants in two hospital effluents of Ouagadougou. Carbapenem-resistant E. coli and K. pneumoniae were selectively isolated from wastewater collected from two public hospitals in Ouagadougou, Burkina Faso. Bacterial species were identified via MALDI-TOF mass spectrometry. Carbapenemase production was studied phenotypically using antibiotic susceptibility testing via the disk diffusion method. The presence of carbapenemases was further characterized by PCR. A total of 14 E. coli (13.59%) and 19 K. pneumoniae (17.92%) carbapenemase-producing isolates were identified with different distributions. They were, respectively, blaNDM (71.43%), blaVIM (42.86%), blaIMP (28.57%), blaKPC (14.29%), blaOXA-48 (14.29%); and blaKPC (68.42%), blaNDM (68.42%), blaIMP (10.53%), blaVIM (10.53%), and blaOXA-48 (5.26%). In addition, eight (57.14%) E. coli and eleven (57.89%) K. pneumoniae isolates exhibited more than one carbapenemase, KPC and NDM being the most prevalent combination. Our results highlight the presence of clinically relevant carbapenemase-producing isolates in hospital effluents, suggesting their presence also in hospitals. Their spread into the environment via hospital effluents calls for intensive antimicrobial resistance (AMR) surveillance.

Bridging gut microbiota composition with extended-spectrum beta-lactamase Enterobacteriales faecal carriage in critically ill patients (microbe cohort study).

BACKGROUND: The worldwide dissemination of extended spectrum beta-lactamase producing Enterobacteriales (ESBL-E) is of major concern. Microbiota may play a role in the host resistance to colonization with ESBL-E, but the underlying mechanisms remain unknown. We aimed to compare the gut microbiota composition between ESBL-producing E. coli or K. pneumoniae carriers and ESBL-E non-carriers according to the bacterial species. RESULTS: Among 255 patients included, 11 (4,3%) were colonized with ESBL-producing E. coli and 6 (2,4%) with ESBL-producing K. pneumoniae, which were compared with age- and sex-matched ESBL-E non carriers. While no significant differences were found between ESBL-producing E. coli carriers and non-carriers, gut bacteriobiota α-diversity was decreased in ESBL-K. pneumoniae faecal carriers compared both with non-carriers (p = 0.05), and with ESBL-producing E. coli carriers. The presence of Sellimonas intestinalis was associated with the absence of ESBL-producing E. coli fecal carriage. Campylobacter ureolyticus, Campylobacter hominis, bacteria belonging to Clostridium cluster XI and Saccharomyces sp. were associated with the absence of ESBL-producing K. pneumoniae faecal carriage. CONCLUSIONS: The composition of the gut microbiota differs between ESBL-producing E. coli and K. pneumoniae faecal carriers suggesting that microbial species should be taken into account when investigating the role of gut microbiota in resistance to gut colonization with ESBL-E. TRIAL REGISTRATION NUMBER: NCT04131569, date of registration: October 18, 2019.

Performance of real-time PCR in suspected haemodialysis catheter-related bloodstream infection: a proof-of-concept study.

Background: Catheter-related bloodstream infections (CRBIs) remain a major cause of mortality in haemodialysis (HD) patients with central venous catheters (CVCs), especially because of the non-specific symptomatology and the delay in microbiological diagnosis with possible use of non-optimal empiric antibiotics. Moreover, empiric broad-spectrum antibiotics increase antibiotic resistance development. This study aims to evaluate the diagnostic performance of real-time polymerase chain reaction (rt-PCR) in suspected HD CRBIs compared with blood cultures. Methods: A blood sample for rt-PCR was collected simultaneously with each pair of blood cultures for suspected HD CRBI. The rt-PCR was performed on the whole blood, without any enrichment stage and with specific DNA primers: 16S (universal bacterial), Staphylococcus spp., Staphylococcus aureus and mecA. Each successive patient with a suspected HD CRBI in the HD centre of Bordeaux University Hospital was included. Performance tests were used to compare the result obtained in each rt-PCR assay with its corresponding routine blood culture. Results: Eighty-four paired samples were collected and compared for 40 suspected HD CRBI events in 37 patients. Among these, 13 (32.5%) were diagnosed as HD CRBI. All rt-PCRs except mecA (insufficient number of positive samples) showed high diagnostic performances within 3.5 h: 16S (sensitivity 100%, specificity 78%), Staphylococcus spp. (sensitivity 100%, specificity 97%), S. aureus (sensitivity 100%, specificity 99%). Based on the rt-PCR results, antibiotics could be more appropriately targeted, thus cutting anti-cocci Gram-positive therapy from 77% to 29%. Conclusions: The performance of rt-PCR in suspected HD CRBI events showed fast and high diagnostic accuracy. Its use would improve HD CRBI management with an antibiotic consumption decrease.

Molecular Determinants for OMF Selectivity in Tripartite RND Multidrug Efflux Systems.

Tripartite multidrug RND efflux systems made of an inner membrane transporter, an outer membrane factor (OMF) and a periplasmic adaptor protein (PAP) form a canal to expel drugs across Gram-negative cell wall. Structures of MexA-MexB-OprM and AcrA-AcrB-TolC, from Pseudomonas aeruginosa and Escherichia coli, respectively, depict a reduced interfacial contact between OMF and PAP, making unclear the comprehension of how OMF is recruited. Here, we show that a Q93R mutation of MexA located in the α-hairpin domain increases antibiotic resistance in the MexAQ93R-MexB-OprM-expressed strain. Electron microscopy single-particle analysis reveals that this mutation promotes the formation of tripartite complexes with OprM and non-cognate components OprN and TolC. Evidence indicates that MexAQ93R self-assembles into a hexameric form, likely due to interprotomer interactions between paired R93 and D113 amino acids. C-terminal deletion of OprM prevents the formation of tripartite complexes when mixed with MexA and MexB components but not when replacing MexA with MexAQ93R. This study reveals the Q93R MexA mutation and the OprM C-terminal peptide as molecular determinants modulating the assembly process efficacy with cognate and non-cognate OMFs, even though they are outside the interfacial contact. It provides insights into how OMF selectivity operates during the formation of the tripartite complex.

[Diagnosis and treatment of catheter-related bloodstream infection in hemodialysis: 10 years later]. / Diagnostic et prise en charge des bactériémies liées au cathéter d'hémodialyse : 10 ans après les dernières recommandations.

Patients in hemodialysis on central venous catheter as vascular access are at risk of infections. Catheter-related bloodstream infection is one of the most serious catheter-complications in hemodialysis patients. Its clinical and microbiological diagnosis is challenging. The implementation of empiric antibiotic therapy is based on old recommendations proposing the combination of a molecule targeting methicillin-resistant Staphylococcus aureus and a betalactamin active on P. aeruginosa, and also adapting this probabilistic treatment by carrying out a microbiological register on a local scale, which is rarely done. In our hemodialysis center at Bordeaux University Hospital, an analysis of the microorganisms causing all catheter-related bloodstream infection over the period 2018-2020 enabled us to propose, in agreement with the infectious disease specialists, an adapted probabilistic antibiotic therapy protocol. This approach allowed us to observe a low incidence of meticillinoresistance of Staphylococcus. For catheters inserted more than 6 months ago, we observed no Staphylococcus, no multi-resistant Pseudomonas, and only 2% of Enterobacteria resistant to cephalosporins. A frequent updating of the microbiological epidemiology of catheter-related bloodstream infection, in partnership with the infectious diseases team in each hemodialysis center, allowing an adaptation of the probabilistic antibiotic therapy, and seems to have a good feasibility. This strategy might favor the preservation of microbial ecology on an individual and collective scale in maintenance hemodialysis patients.

Extended spectrum beta-lactamase producing Enterobacterales faecal carriage in a medical intensive care unit: low rates of cross-transmission and infection.

Background: Extended-spectrum beta-lactamases-producing Enterobacterales (ESBL-E) are disseminating worldwide especially in Intensive Care Units (ICUs) and are responsible for increased health costs and mortality. The aims of this work were to study ESBL-E dissemination in ICU and to assess the impact of ESBL-E fecal carriage on subsequent infections during a non-outbreak situation. Methods: We therefore screened every patient at admission then once a week in a medical ICU between January and June 2015. Each ESBL-E isolate was characterized by ESBL genes PCR amplification and the clonal dissemination was assessed by Pulsed-Field Gel Electrophoresis (PFGE). Results: Among the 608 screened patients, 55 (9%) were colonized by ESBL-E. Forty-four isolates were available for further analysis. Most of them (43/44, 98%) contained a ESBL gene from the CTX-M group. Only one case of ESBL-E cross-transmission occurred, even for acquired ESBL-E colonization. Subsequent infection by ESBL-E occurred in 6/55 (11%) patients and infecting ESBL-E strains were the colonizing ones. ESBL-E faecal carriage had a negative predictive value of 100% and a positive predictive value of 40% to predict ESBL-E ventilator associated-pneumonia (VAP). Alternatives to carbapenems consisting in piperacillin-tazobactam, ceftolozane-tazobactam and ceftazidime-avibactam were all active on this panel of ESBL-E. Conclusions: ESBL-E expansion and acquisition in ICU in a non-outbreak situation are not any more fully explained by cross-transmission. Mechanisms underlying ESBL-E dissemination in ICU are still to investigate. Interestingly, as far as we know, our study demonstrates for the first time by PFGE that the colonizing strain is indeed the infecting one in case of subsequent ESBL-E infection. Nevertheless, subsequent ESBL-E infection remains a rare event conferring poor positive predictive value for ESBL-E colonization to predict ESBL-E VAP. Relevance of systematic ESBL-E faecal screening at ICU admission and during ICU stay needs further investigation.

Acquisition of Extended-Spectrum ß-Lactamase GES-6 Leading to Resistance to Ceftolozane-Tazobactam Combination in Pseudomonas aeruginosa.

A clinical Pseudomonas aeruginosa isolate resistant to all ß-lactams, including ceftolozane-tazobactam and carbapenems, was recovered. It belonged to sequence type 235 and produced the extended-spectrum ß-lactamase (ESBL) GES-6 differing from GES-1 by two amino acid substitutions (E104K and G170S). GES-6 possessed an increased hydrolytic activity toward carbapenems and to ceftolozane and a decreased susceptibility to ß-lactamase inhibitors compared to GES-1, except for avibactam. We show here that resistance to ceftolozane-tazobactam may occur through acquisition of a specific ESBL in P. aeruginosa but that ceftazidime-avibactam combination remains an effective alternative.

Whole-Genome Sequence Analysis of Multidrug-Resistant Campylobacter Isolates: a Focus on Aminoglycoside Resistance Determinants.

A whole-genome sequencing (WGS) approach was conducted in order to identify the molecular determinants associated with antimicrobial resistance in 12 multidrug-resistant Campylobacter jejuni and Campylobacter coli isolates, with a focus on aminoglycoside resistance determinants. Two variants of a new aminoglycoside phosphotransferase gene [aph(2″)-Ii1 and aph(2″)-Ii2 ] putatively associated with gentamicin resistance were found. In addition, the following new genes were identified for the first time in Campylobacter: a lincosamide nucleotidyltransferase gene [lnu(G)], likely associated with lincomycin resistance, and two resistance enzyme genes (spw and apmA) similar to those found in Staphylococcus aureus, which may confer spectinomycin and gentamicin resistance, respectively. A C1192T mutation of the 16S rRNA gene that may be involved in spectinomycin resistance was also found in a C. coli isolate. Genes identified in the present study were located either on the bacterial chromosome or on plasmids that could be transferred naturally. Their role in aminoglycoside resistance remains to be supported by genetic studies. Regarding the other antimicrobial agents studied, i.e., ampicillin, ciprofloxacin, erythromycin, and tetracycline, a perfect correlation between antimicrobial phenotypes and genotypes was found. Overall, our data suggest that WGS analysis is a powerful tool for identifying resistance determinants in Campylobacter and can disclose the full genetic elements associated with resistance, including antimicrobial compounds not tested routinely in antimicrobial susceptibility testing.

Detection of colistin-resistant Gram-negative rods by using the SuperPolymyxin medium.

The commercial SuperPolymyxin medium (ELITechGroup, Puteaux, France), currently licensed in Europe, is aimed to screen for either intrinsic or acquired colistin resistance in Gram negatives. It was tested for screening colistin-resistant Gram-negative rods from bacterial cultures of 145 colistin-resistant and 86 colistin-susceptible Gram-negative rods isolates. It exhibited a sensitivity and specificity of 95.2% (138/145) and 95.3% (82/86), respectively. The sensitivity for the detection of the 25 isolates carrying plasmid-mediated colistin resistance genes (mcr-1, mcr-2, mcr-3, and mcr-4) from bacterial cultures was of 100%. It was also evaluated for the detection of colistin-resistant Gram-negative rods from 57 rectal swab samples (41 clinical rectal swab samples and from 16 spiked rectal swab samples supplemented with colistin-resistant enterobacterial isolates carrying mcr genes). The overall sensitivity and specificity were of 100% (33/33) and 90.3% (56/62), respectively. The detection of isolates carrying plasmid-mediated mcr-like genes from rectal swabs was achieved with a lowest detection limit of 103 to 104 CFU/mL. The SuperPolymyxin medium is adapted for screening and detection of colistin-resistant isolates from bacterial cultures and rectal swab samples, regardless of the level and the mechanism of colistin resistance. It might be useful in the context of prevention of outbreaks due to colistin-resistant isolates and for epidemiological surveillance.

Contribution of a multiplex serological test for the preoperative diagnosis of prosthetic joint infection: a prospective study.

BACKGROUND: Prosthetic joint infection (PJI) is a severe complication of orthopaedic surgery. Preoperative diagnosis, although sometimes difficult, is key to choose the relevant treatment. METHODS: We conducted a prospective study aimed at evaluating the diagnostic performance of a multiplex serological test for the pre-operative diagnosis of PJI. Blood samples were collected between 1 July 2016 and 31 July 2017 among patients referred for suspected PJI that occurred at least six weeks prior. Infection diagnosis was confirmed using intraoperative bacteriological cultures during prosthetic exchange. RESULTS: Seventy-one patients were included, with a median age of 73 years (interquartile range [IQR]: 66-81) and 40 (56%) were male. Twenty-six patients had aseptic loosening and 45 patients had PJI. Among the latter, median time since the last surgery was 96 weeks (IQR: 20-324). Intraoperative cultures found Staphylococcus spp, Streptococcus spp or both in 39, 5 and 1 patients, respectively. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 81.8, 95.4, 97.3 and 72.4%, respectively, for all patients and 87.5, 93.5, 94.6 and 85.3%, respectively, for staphylococcal infections. Patients with false negative (FN) results had a significantly lower blood lymphocyte count (p = .045). CONCLUSIONS: Multiplex serological test performed well among patients with chronic staphylococcal prosthetic infection. This approach could contribute to PJI diagnosis especially in patients for whom the pre-operative analysis of joint fluid is not informative.

Evaluation of three broth microdilution systems to determine colistin susceptibility of Gram-negative bacilli.

Background: The broth microdilution (BMD) method is currently the recommended technique to determine susceptibility to colistin. Objectives: We evaluated the accuracy of three commercialized BMD panels [Sensititre (ThermoFisher Diagnostics), UMIC (Biocentric) and MicroScan (Beckman Coulter)] to determine colistin susceptibility. Methods: A collection of 185 isolates of Gram-negative bacilli (133 colistin resistant and 52 colistin susceptible) was tested. Manual BMD according to EUCAST guidelines was used as the reference method, and EUCAST 2017 breakpoints were used for susceptibility categorization. Results: The UMIC system gave the highest rate of very major errors (11.3%) compared with the Sensititre and MicroScan systems (3% and 0.8%, respectively). A high rate of major errors (26.9%) was found with the MicroScan system due to an overestimation of the MICs for the non-fermenting Gram-negative bacilli, whereas no major errors were found with the Sensititre and UMIC systems. Conclusions: The UMIC system was easy to use, but failed to detect >10% of colistin-resistant isolates. The MicroScan system showed excellent results for enterobacterial isolates, but non-susceptible results for non-fermenters should be confirmed by another method and the range of MICs tested was narrow. The Sensititre system was the most reliable marketed BMD panel with a categorical agreement of 97.8%.

High-Level Resistance to Colistin Mediated by Various Mutations in the crrB Gene among Carbapenemase-Producing Klebsiella pneumoniae.

Mutations in crrAB genes encoding a two-component regulator involved in modifications of lipopolysaccharide were searched for among a collection of colistin-resistant Klebsiella pneumoniae isolates. Four isolates, respectively, producing carbapenemases NDM-1, OXA-181, or KPC-2 showed mutated CrrB proteins compared with those in wild-type strains. Complementation assays with a wild-type CrrB protein restored the susceptibility to colistin in all cases, confirming the involvement of the identified substitutions in the resistance phenotype.

Prevalence of faecal carriage of colistin-resistant Gram-negative rods in a university hospital in western France, 2016.

Plasmid-mediated and chromosomally-encoded colistin resistance is increasingly being reported worldwide. We aimed to determine the prevalence of faecal carriage of colistin-resistant Gram-negative rod isolates in a university hospital in western France. From February to May 2016, rectal swabs from 653 patients hospitalized in various clinical settings were recovered and subsequently screened for colistin resistance using the SuperPolymyxin medium. Antimicrobial susceptibilities were determined according to EUCAST guidelines. Genetic detection of plasmid-mediated colistin resistance was performed by PCR. The faecal carriage with intrinsic colistin-resistant isolates was high (23 %), while the faecal carriage with Gram-negative rods showing acquired resistance was low (1.4 %). No isolate carried the plasmid-mediated mcr-1/mcr-2 genes. It was noteworthy that none of the patients carrying isolates with acquired colistin resistance had previously received a colistin-based treatment, while these isolates were not multidrug resistant.

Hafnia, an enterobacterial genus naturally resistant to colistin revealed by three susceptibility testing methods.

Objectives: To determine the susceptibility to colistin of Hafnia alvei and Hafnia paralvei, and to compare methods for colistin resistance detection in the Hafnia genus. Methods: A collection of 25 Hafnia isolates was studied. Species were identified by using 16S rRNA gene sequencing with subsequent phylogeny analysis. Susceptibility to colistin was determined using the broth microdilution (BMD) reference method, the Phoenix automated system, the Rapid Polymyxin NP test, the Etest system and the disc diffusion method. Results: The collection consisted of 15 H. alvei and 10 H. paralvei isolates. Based on the 16S rRNA analysis, a close relationship of the Hafnia genus with naturally colistin-resistant enterobacterial genera (Proteus, Morganella, Providencia and Serratia) was identified. Susceptibility testing performed using the BMD method, the Phoenix automated system and the Rapid Polymyxin NP test revealed a high rate of colistin resistance (96%). Underestimation of colistin resistance using Etest strips (72%) and the disc diffusion method (0%) was observed. Conclusions: The high rate of colistin resistance observed within the Hafnia genus and its close phylogenetic relationship with naturally colistin-resistant genera suggest that Hafnia is a naturally colistin-resistant enterobacterial genus.

Efficacy of debridement, antibiotic therapy and implant retention within three months during postoperative instrumented spine infections.

BACKGROUND: Postoperative instrumented spine infection (PISI) is a severe complication of invasive spine procedures. METHODS: Retrospective study of patients treated for PISI between 1st January 2008 and 31st December 2012 in a French University Hospital. The objectives of this study were to describe the outcome of patients treated with debridement-irrigation, antibiotic therapy and implant retention (DAIR) within three months after the occurrence of PISI and to identify factors associated with relapse. RESULTS: Among 4290 patients who underwent spinal arthrodesis surgery during the 5-year study period, 129 had PISI treated by debridement-irrigation in the first three months (3.0%, 95% confidence interval [95%CI]: 2.5-3.5). Fifty-two (40%) were female and the median age was 57 years. Fourteen patients (10.8%) had diabetes and 73 (56.6%) had a BMI (Body Mass Index) ≥25 kg/m2. Staphylocccus aureus, enterobacteria or polymicrobial infections were identified in 44.0, 18.0 and 13.0% of cases, respectively. One hundred and six patients (82.2%) and one hundred and twenty-one patients (93.8%) were cured after one DAIR and after two DAIR, respectively. In multivariate logistic analysis, polymicrobial infection was associated with relapse (Odd Ratio [OR] = 3.81; 95%CI: 1.06-13.66; p = .03), while a BMI ≥25 kg/m2 was a protective factor (OR =0.25; 95%CI: 0.07-0.89; p = .03). CONCLUSION: DAIR may be effective for PISI when performed within the first 3 months after onset of infection. Relapses are significantly associated with polymicrobial infection and negatively associated with moderate overweight. These results need to be confirmed in future prospective studies.

High Prevalence of Gut Microbiota Colonization with Broad-Spectrum Cephalosporin Resistant Enterobacteriaceae in a Tunisian Intensive Care Unit.

Healthcare-associated infections due to cefotaxime-resistant (CTX-R) Enterobacteriaceae have become a major public health threat, especially in intensive care units (ICUs). Often acquired nosocomially, CTX-R Enterobacteriaceae can be introduced initially by patients at admission. This study aimed to determine the prevalence and genetic characteristics of CTX-R Enterobacteriaceae-intestinal carriage in ICU patients, to evaluate the rate of acquisition of these organisms during hospitalization, and to explore some of the associated risk factors for both carriage and acquisition. Between December 2014 and February 2015, the 63 patients admitted in the ICU of Charles Nicolle hospital were screened for rectal CTX-R Enterobacteriaceae colonization at admission and once weekly thereafter to identify acquisition. CTX-R Enterobacteriaceae fecal carriage rate was 20.63% (13/63) at admission. Among the 50 non-carriers, 35 were resampled during their hospitalization and the acquisition rate was 42.85% (15/35). Overall, 35 CTX-R Enterobacteriaceae isolates were collected from 28 patients (25 Klebsiella pneumoniae, seven Escherichia coli, and three Enterobacter cloacae strains). Seven patients were simultaneously colonized with two CTX-R Enterobacteriaceae isolates. CTX-M-15 was detected in most of the CTX-R Enterobacteriaceae isolates (30/35, 88.23%). Three strains co-produced CMY-4 and 22 strains were carbapenem-resistant and co-produced a carbapenemase [OXA-48 (n = 13) or NDM-1 (n = 6)]. Molecular typing of K. pneumoniae strains, revealed eight Pulsed field gel electrophoresis (PFGE) patterns and four sequence types (ST) [ST101, ST147, ST429, and ST336]. However, E. coli isolates were genetically unrelated and belonged to A (n = 2), B1 (n = 2) and B2 (n = 3) phylogenetic groups and to ST131 (two strains), ST572 (two strains), ST615 (one strain) and ST617 (one strain). Five colonized patients were infected by CTX-R Enterobacteriaceae (four with the same strain identified from their rectal swab and one with a different strain). Whether imported or acquired during the stay in the ICU, colonization by CTX-R Enterobacteriaceae is a major risk factor for the occurrence of serious nosocomial infections. Their systematic screening in fecal carriage is mandatory to prevent the spread of these multidrug resistant bacteria.