Outbreak of Pseudomonas aeruginosa High-Risk Clone ST309 Serotype O11 Featuring blaPER-1 and qnrVC6.

Pseudomonas aeruginosa is a leading cause of hospital-acquired infections worldwide. Biofilm production, antibiotic resistance, and a wide range of virulence factors contribute to their persistence in nosocomial environments. We describe an outbreak caused by a multidrug-resistant P. aeruginosa strain in an ICU. Antibiotic susceptibility was determined and blaPER-1 and qnrVC were amplified via PCR. Clonality was determined using PFGE and biofilm formation was studied with a static model. A combination of antibiotics was assessed on both planktonic cells and biofilms. WGS was performed on five isolates. All isolates were clonally related, resistant to ceftazidime, cefepime, amikacin, and ceftolozane-tazobactam, and harbored blaPER-1; 11/19 possessed qnrVC. Meropenem and ciprofloxacin reduced the biofilm biomass; however, the response to antibiotic combinations with rifampicin was different between planktonic cells and biofilms. WGS revealed that the isolates belonged to ST309 and serotype O11. blaPER-1 and qnrVC6 were associated with a tandem of ISCR1 as part of a complex class one integron, with aac(6')-Il and ltrA as gene cassettes. The structure was associated upstream and downstream with Tn4662 and flanked by direct repeats, suggesting its horizontal mobilization capability as a composite transposon. ST309 is considered an emerging high-risk clone that should be monitored in the Americas.

Great Plasticity in a Great Pathogen: Capsular Types, Virulence Factors and Biofilm Formation in ESBL-Producing Klebsiella pneumoniae from Pediatric Infections in Uruguay.

Klebsiella pneumoniae is widely recognized as an opportunistic hospital and community pathogen. It is one of the priority microorganisms included in the ESKAPE group, and its antibiotic resistance related to extended-spectrum ß-lactamases (ESBL) is a global public health concern. The multi-drug resistance (MDR) phenotype, in combination with pathogenicity factors, could enhance the ability of this pathogen to cause clinical infections. The aim of this study was to characterize pathogenicity factors and biofilm formation in ESBL-producing K. pneumoniae from pediatric clinical infections. Capsular types, virulence factors, and sequence types were characterized by PCR. Biofilm formation was determined by a semiquantitative microtiter technique. MDR phenotype and statistical analysis were performed. The K24 capsular type (27%), virulence factors related to iron uptake fyuA (35%) and kfuBC (27%), and sequence types ST14 (18%) and ST45 (18%) were the most frequently detected. Most of the strains were biofilm producers: weak (22%), moderate (22%), or strong (12%). In 62% of the strains, an MDR phenotype was detected. Strains with K24 capsular type showed an association with ST45 and the presence of fyuA; strains with kfuBC showed an association with moderate or strong biofilm production and belonging to ST14. Weak or no biofilm producers were associated with the absence of kfuBC. The MDR phenotype was associated with the main ESBL gene, blaCTX-M-15. The high plasticity of K. pneumoniae to acquire an MDR phenotype, in combination with the factors exposed in this report, could make it even more difficult to achieve a good clinical outcome with the available therapeutics.

Shiga Toxin-Producing Escherichia coli (STEC) Associated with Calf Mortality in Uruguay.

In Uruguay, the mortality of dairy calves due to infectious diseases is high. Escherichia coli is a natural inhabitant of the intestinal microbiota, but can cause several infections. The aim of the work was to characterize E. coli isolates from intestinal and extraintestinal origin of dead newborn calves. Using PCR, virulence gene characteristics of pathogenic E. coli were searched. The pathogenic E. coli were molecularly characterized and the phylogroup, serogroup and the Stx subtype were determined. Antibiotic susceptibility was determined using the Kirby-Bauer disk diffusion method and plasmid-mediated quinolone resistance (PMQR) genes with PCR. Finally, clonal relationships were inferred using PFGE. Gene characteristics of the Shiga toxin-producing E. coli (STEC), Enteropathogenic E. coli (EPEC) and Necrotoxigenic E. coli (NTEC) were identified. The prevalence of the iucD, afa8E, f17, papC, stx1, eae and ehxA genes was high and no f5, f41, saa, sfaDE, cdtIV, lt, sta or stx2 were detected. The prevalence of STEC gene stx1 in the dead calves stood out and was higher compared with previous studies conducted in live calves, and STEC LEE+ (Enterohemorrhagic E. coli (EHEC)) isolates with stx1/eae/ehxA genotypes were more frequently identified in the intestinal than in the extraintestinal environment. E. coli isolates were assigned to phylogroups A, B1, D and E, and some belonged to the O111 serogroup. stx1a and stx1c subtypes were determined in STEC. A high prevalence of multi-resistance among STEC and qnrB genes was determined. The PFGE showed a high diversity of pathogenic strains with similar genetic profiles. It can be speculated that EHEC (stx1/eae/ehxA) could play an important role in mortality. The afa8E, f17G1 and papC genes could also have a role in calf mortality. Multidrug resistance defies disease treatment and increases the risk of death, while the potential transmissibility of genes to other species constitutes a threat to public health.

Phenotypic and genotypic survey of antibiotic resistance in Salmonella enterica isolates from dairy farms in Uruguay.

Salmonella enterica is an important zoonotic pathogen that is frequently identified in dairy farming systems. An increase in antibiotic resistance has led to inadequate results of treatments, with impacts on animal and human health. Here, the phenotypic and genotypic susceptibility patterns of Salmonella isolates from dairy cattle and dairy farm environments were evaluated and compared. A collection of 75 S. enterica isolates were evaluated, and their phenotypic susceptibility was determined. For genotypic characterization, the whole genomes of the isolates were sequenced, and geno-serotypes, sequence types (STs) and core-genome-sequence types were determined using the EnteroBase pipeline. To characterize antibiotic resistance genes and gene mutations, tools from the Center for Genomic Epidemiology were used. Salmonella Dublin (SDu), S. Typhimurium (STy), S. Anatum (SAn), S. Newport (SNe), S. Agona (Sag), S. Montevideo (SMo) and IIIb 61:i:z53 were included in the collection. A single sequence type was detected per serovar. Phenotypic non-susceptibility to streptomycin and tetracycline was very frequent in the collection, and high non-susceptibility to ciprofloxacin was also observed. Multidrug resistance (MDR) was observed in 42 isolates (56.0%), with SAn and STy presenting higher MDR than the other serovars, showing non-susceptibility to up to 6 groups of antibiotics. Genomic analysis revealed the presence of 21 genes associated with antimicrobial resistance (AMR) in Salmonella isolates. More than 60% of the isolates carried some gene associated with resistance to aminoglycosides and tetracyclines. Only one gene associated with beta-lactam resistance was found, in seven isolates. Two different mutations were identified, parC_T57S and acrB_R717Q, which confer resistance to quinolones and azithromycin, respectively. The accuracy of predicting antimicrobial resistance phenotypes based on AMR genotypes was 83.7%. The genomic approach does not replace the phenotypic assay but offers valuable information for the survey of circulating antimicrobial resistance. This work represents one of the first studies evaluating phenotypic and genotypic AMR in Salmonella from dairy cattle in South America.

Novel Resistance Regions Carrying TnaphA6, blaVIM-2, and blaPER-1, Embedded in an ISPa40-Derived Transposon from Two Multi-Resistant Pseudomonas aeruginosa Clinical Isolates.

Antibiotic resistance is an alarming problem throughout the world and carbapenem-resistant Pseudomonas aeruginosa has been cataloged as critical in the World Health Organization list of microorganisms in urgent need for the development of new antimicrobials. In this work, we describe two novel resistance regions responsible for conferring a multidrug resistance phenotype to two clinical isolates of P. aeruginosa (Pa873 and Pa6415) obtained from patients hospitalized in the ICU of University Hospital of Uruguay. Bacterial identification and antibiotic susceptibility tests were performed using MALDI-TOF and the Vitek 2 system, respectively. WGS was performed for both isolates using Oxford Nanopore Technologies and Illumina and processed by means of hybrid assembly. Both isolates were resistant to ceftazidime, cefepime, piperacillin-tazobactam, aztreonam, and imipenem. Strain Pa6415 also showed resistance to ciprofloxacin. Both strains displayed MICs below the susceptibility breakpoint for CAZ-AVI plus 4 mg/L of aztreonam as well as cefiderocol. Both resistance regions are flanked by the left and right inverted repeats of ISPa40 in two small regions spanning 39.3 and 35.6 kb, for Pa6415 and Pa873, respectively. The resistance region of Pa6415 includes TnaphA6, and the new Tn7516 consists of IRi, In899, qacEΔ1-sul1-ISCR1, qnrVC6-ISCR1-blaPER-1-qacEΔ1-sul1, araJ-like, IS481-like tnpA, ISPa17, and IRR. On the other hand, the resistance region of Pa873 includes Tnaph6 and the new Tn7517 (IRi, In899, qacEΔ1-sul1, ISCR1-blaPER-1-qacEΔ1-sul1, araJ-like, IS481-like tnpA, ISPa17, and IRR). It is necessary to monitor the emergence of genetic structures that threaten to invalidate the available therapeutic resources.

Imported One-Day-Old Chicks as Trojan Horses for Multidrug-Resistant Priority Pathogens Harboring mcr-9, rmtG, and Extended-Spectrum ß-Lactamase Genes.

Antimicrobial resistance is a critical issue that is no longer restricted to hospital settings but also represents a growing problem involving intensive animal production systems. In this study, we performed a microbiological and molecular investigation of priority pathogens carrying transferable resistance genes to critical antimicrobials in 1-day-old chickens imported from Brazil to Uruguay. Bacterial identification was performed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry, and antibiotic susceptibility was determined by Sensititre. Antimicrobial resistance genes were sought by PCR, and clonality was assessed by pulsed-field gel electrophoresis (PFGE). Four multidrug-resistant (MDR) representative strains were sequenced by an Illumina and/or Oxford Nanopore Technologies device. Twenty-eight MDR isolates were identified as Escherichia coli (n = 14), Enterobacter cloacae (n = 11), or Klebsiella pneumoniae (n = 3). While resistance to oxyiminocephalosporins was due to blaCTX-M-2, blaCTX-M-8, blaCTX-M-15, blaCTX-M-55, and blaCMY-2, plasmid-mediated quinolone resistance was associated with the qnrB19, qnrE1, and qnrB2 genes. Finally, resistance to aminoglycosides and fosfomycin was due to the presence of 16S rRNA methyltransferase rmtG and fosA-type genes, respectively. Short- and long-read genome sequencing of E. cloacae strain ODC_Eclo3 revealed the presence of IncQ/rmtG (pUR-EC3.1; 7,400 bp), IncHI2A/mcr-9.1/blaCTX-M-2 (pUR-EC3.2, ST16 [pMLST; 408,436 bp), and IncN2/qnrB19/aacC3/aph(3″)-Ib (pUR-EC3.3) resistance plasmids. Strikingly, the blaCTX-M-2 gene was carried by a novel Tn1696-like composite transposon designated Tn7337. In summary, we report that imported 1-day-old chicks can act as Trojan horses for the hidden spread of WHO critical-priority MDR pathogens harboring mcr-9, rmtG, and extended-spectrum ß-lactamase genes in poultry farms, which is a critical issue from a One Health perspective. IMPORTANCE Antimicrobial resistance is considered a significant problem for global health, including within the concept of One Health; therefore, the food chain connects human health and animal health directly. In this work, we searched for microorganisms resistant to antibiotics considered critical for human health in intestinal microbiota of 1-day-old baby chicks imported to Uruguay from Brazil. We describe genes for resistance to antibiotics whose use the WHO has indicated to "watch" or "reserve" (AWaRe classification), such as rmtG and mcr9.1, which confer resistance to all the aminoglycosides and colistin, respectively, among other genes, and their presence in new mobile genetic elements that favor its dissemination. The sustained entry of these microorganisms evades the sanitary measures implemented by the countries and production establishments to reduce the selection of resistant microorganisms. These silently imported resistant microorganisms could explain a considerable part of the antimicrobial resistance problems found in the production stages of the system.

In Vivo High Plasticity of Multi-Drug Resistant ST258 Klebsiella pneumoniae.

Carbapenemase production in Enterobacterales clinical isolates is a global threat. Multi-drug resistant Klebsiella pneumoniae harboring carbapenemases are a major concern among the hospital settings in Latin America. Aim: The aim of this study was to analyze the genetic relatedness between three isolates of K. pneumoniae recovered from one patient in the same bacteriological round on the same day, which exhibited different susceptibility profiles to carbapenems (CP) and to colistin (Col). Isolates' profiles were as follows (susceptible-S/resistant-R): CPS/ColR, CPR/ColR, and CPR/ColS. Pulse-field gel electrophoresis, multilocus sequence typing, and whole genome sequencing were performed. Conjugation assays were carried out and PCR determination in transconjugants (Tcs) was made for: blaCTX-M-groups, blaNDM, blaKPC, blaTEM, qnr alleles, aac(6')Ib-cr, ermB, and plasmid incompatibility groups (Inc). Results: All isolates belonged to the same clone, to ST258 and harbored blaCTX-M-14, blaCTX-M-15, qnrA1, qnrB1, aac(6')Ib-cr, and wzi154 (capsule-locus KL107). One isolate had additional wzi gene, wzi109 (capsule-locus KL36). In CPR isolates, the pattern was explained for blaNDM-1 or blaNDM-1/blaKPC-2 presence, and in ColR for IS5-like element insertion in mgrB at different positions. Co-mobilization of blaNDM-1/qnrA1 was associated to a different plasmid Inc (A/C-FII) in both blaNDM-1 donors. Mobilization of blaCTX-M-14 was related to IncI1 in one donor. Conclusion: These findings highlight the potential plasticity of ST258 K. pneumoniae clone. To the best of our knowledge, this is the first description of blaNDM-1/blaKPC-2-producing K. pneumoniae ST258 in Latin America.

Transferable Resistance to Highest Priority Critically Important Antibiotics for Human Health in Escherichia coli Strains Obtained From Livestock Feces in Uruguay.

The aim of this work was to detect Escherichia coli isolates displaying resistance to oxyimino-cephalosporins, quinolones, and colistin in feces from livestock in Uruguay. During 2016-2019, fecal samples from 132 broiler and layer chicken flocks, 100 calves, and 50 pigs, were studied in Uruguay. Samples were cultured on MacConkey Agar plates supplemented with ciprofloxacin, ceftriaxone, or colistin. E. coli isolates were identified by mass spectrometry and antibiotic susceptibility testing was performed by disk diffusion agar method and colistin agar test. Antibiotic resistance genes were detected by polymerase chain reaction and sequencing. The most frequently detected resistance gene was qnrB19, recovered from 87 animals. Regarding plasmid-mediated quinolone resistance genes, qnrS1 was the second in prevalence (23 animals) followed by qnrE1, found in 6 chickens and two calves. Regarding resistance to oxyimino-cephalosporins, 8 different ß-lactamase genes were detected: bla CTX-M-8 and bla CMY-2 were found in 23 and 19 animals, respectively; next, bla CTX-M-2 and bla SHV-12 in 7 animals each, followed by bla CTX-M-14 in 5, bla CTX-M-15 and bla SHV2a in 2, and bla CTX-M-55 in a single animal. Finally, the mcr-1 gene was detected only in 8 pigs from a single farm, and in a chicken. Isolates carrying bla CMY-2 and bla SHV-12 were also found in these animals, including two isolates featuring the bla CMY-2/mcr-1 genotype. To the best of our knowledge, this is the first work in which the search for transferable resistance to highest priority critically important antibiotics for human health is carried out in chickens and pigs chains of production animals in Uruguay.

Characterization of the Different Stages of Biofilm Formation and Antibiotic Susceptibility in a Clinical Acinetobacter baumannii Strain.

Acinetobacter baumannii is a relevant opportunistic pathogen, and one of the main microorganisms responsible for outbreaks in nosocomial infections worldwide. Its pathogenicity is mainly due to its resistance to multiple antibiotics and to its ability to form biofilms on abiotic surfaces. The objective of this study was to characterize the biofilm formation cycle of A. baumannii isolated from a patient in a hospital and compare its antibiotic resistance with the planktonic cells. To study biofilm formation, the classical microtiter assay was used, with crystal violet staining and optical density reading to classify the type of biofilm. Also, the effect of gentamicin and colistin on bacterial biofilm was studied with an extra step of antibiotic addition. For the characterization of the different biofilm formation stages, the strain was grown on a coverslip, and the stain was made with a mixture of fluorophores markers to visualize the biofilm with a confocal laser microscope. It was possible to differentiate the A. baumannii biofilm formation stages. Through these observations, it was possible to estimate the time elapsed between each stage. As the strain was susceptible to colistin and gentamicin, both antibiotics were evaluated after the biofilm was formed. Neither antibiotics showed an effect on the eradication of A. baumannii biofilm.

First three Escherichia coli isolates harbouring mcr-1 in Uruguay.

OBJECTIVE: This report described the first Escherichia coli (E. coli) isolates harbouring mcr-1 in Uruguay. METHODS: Three E. coli isolates were obtained from blood, urine and rectal swabs from different patients in two hospitals. Extended-spectrum ß-lactamases (ESBL), plasmid-encoded (pAmpC) ß-lactamases, plasmid-mediated quinolone resistance (PMQR) genes, class 1 integrons, and mcr-1, mcr-2 and mcr-3 were sought and characterised in three E. coli isolates. Transfer of resistance determinants was assessed by conjugation. Clonality was analysed by multilocus sequence typing. RESULTS: All isolates were categorised as being colistin-resistant and the mcr-1 gene was detected. Two isolates were also resistant to oxyimino cephalosporins: one on account of blaCMY-2 and the other due to blaCTX-M-15, the latter also harbouring transferable quinolone-resistance genes (aac(6')Ib-cr and qnrB). All mcr-1 genes were transferred by conjugation to recipient strains. The mcr-1-bearing isolates belonged to sequence types ST10, ST93 and ST5442. CONCLUSIONS: ST10 is considered as a high-risk clone worldwide. This type of mcr-1-harbouring clone is a major concern for human and animal health and must be under close surveillance. This study detected the presence of mcr-1 for the first time in Uruguay, albeit in an allodemic manner, associated with different antibiotic-resistance genes and from diverse clinical contexts. Considering that colistin is often the last therapeutic option available for multidrug-resistant Gram-negative bacilli infections, it is important to maximise precautions to avoid dissemination of isolates carrying mcr-1.

First characterization of K. pneumoniae ST11 clinical isolates harboring blaKPC-3 in Latin America.

Antimicrobial resistance due to carbapenemase production in Enterobacteriaceae clinical isolates is a global threat. Klebsiellapneumoniae harboring the blaKPC gene is one of the major concerns in hospital settings in Latin America. The aim of this study was to characterize the antibiotic resistance mechanisms and to typify four carbapenem-resistant K. pneumoniae clinical isolates from the city of Manizales, Colombia. We identified blaKPC-3 in all four isolates by polymerase chain reaction and subsequent sequencing. The plasmid-mediated quinolone resistance genes qnrB19-like and aac(6')Ib-cr; fosfomycin resistance gene fosA and an insertion sequence IS5-like in mgrB (colistin resistance) were also detected. Sequence types ST11 with capsular type wzi75, and ST258 with wzi154, were characterized. The blaKPC-3 gene was mobilized in a 100-kb IncFIB conjugative plasmid with vagCD toxin-antitoxin system. This work reports multiple resistance genes in blaKPC-producing K. pneumoniae and the first occurrence of ST11 clinical isolates harboring blaKPC-3 in Latin America.

Characterization of the first blaCTX-M-14/ermB-carrying IncI1 plasmid from Latin America.

Azithromycin represents a valid therapeutic option for gastrointestinal and systemic infections caused by multidrug resistant (MDR) diarrheagenic Escherichia coli, Shigella and Salmonella species. However, acquired macrolide resistance in these species has been increasingly described, mostly related to macrolide modifying enzymes encoded by mph- and erm-type genes. In this study, we characterized the first blaCTX-M-14/ermB-carrying IncI1 plasmid from Latin America, which was detected in a MDR E. coli clinical isolate from Uruguay. Plasmid pUR-EC07 was a 105,836-bp IncI1 ST80 plasmid harboring blaCTX-M-14,blaTEM-1 and ermB, and characterized by a backbone region of 92,554 bp, and a multi resistance region (MRR) of 13,282 bp, bounded by two directly-oriented IS26 elements, and inserted upstream of ResD. The MRR comprised two nested IS26-composite transposons (Tn6651 and Tn6652). Tn6651 included the ermBL-ermB operon flanked by two IS26 copies in opposite direction. Tn6652 included blaTEM-1, with an upstream remnant of a Tn3-family transposon, and blaCTX-M-14, located in a genetic context consisting of ISEcp1∆-IS10-blaCTX-M-14-IS903D. To the best of our knowledge, pUR-EC07 represents the first IncI1 plasmid harboring ermB and blaCTX-M-14 described in Latin America. Given the wide dissemination of IncI-type plasmids in Salmonella enterica, an important concern is represented by the potential transfer of similar plasmids to strains resistant to ciprofloxacin, which would result in the loss of the three main therapeutic resources.

Draft Genome Sequences of Two Multidrug-Resistant Salmonella enterica Serovar Typhimurium Clinical Isolates from Uruguay.

Multidrug-resistant Salmonella enterica isolates are an increasing problem worldwide; nevertheless, the mechanisms responsible for such resistance are rarely well defined. Multidrug-resistant S. enterica serovar Typhimurium isolates ST3224 and ST827 were collected from two patients. The characteristics of both genomes and antimicrobial resistance genes were determined using next-generation sequencing.

Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii in the Intensive Care Unit of Uruguay's University Hospital Identifies the First rmtC Gene in the Species.

Carbapenem-resistant Acinetobacter baumannii (CRAB) infections are an increasing concern in intensive care units (ICUs) worldwide. The combination of carbapenemases and 16S rRNA-methyltransferases (16S-RMTases) further reduces the therapeutic options. OXA-carbapenemase/A. baumannii clone tandems in Latin America have already been described; however, no information exists in this region regarding the occurrence of 16S-RMTases in this microorganism. In addition, the epidemiology of A. baumannii in ICUs and its associated resistance profiles are poorly understood. Our objectives were as follows: to study the clonal relationship and antibiotic resistance profiles of clinical and digestive colonizing A. baumannii isolates in an ICU, to characterize the circulating carbapenemases, and to detect 16S-RMTases. Patients admitted between August 2010 and July 2011 with a clinically predicted hospital stay > 48 hr were included. Pharyngeal and rectal swabs were obtained during the first fortnight after hospitalization. Resistance profiles were determined with MicroScan® and VITEK2 system. Carbapenemases and 16S-RMTases were identified by PCR and sequencing, and clonality was assessed by pulsed-field gel electrophoresis and multilocus sequence typing. Sixty-nine patients were studied and 63 were diagnosed with bacterial infections. Among these, 29 were CRAB isolates; 49 A. baumannii were isolated as digestive colonizers. These 78 isolates were clustered in 7 pulsetypes, mostly belonging to ST79. The only carbapenemase genes detected were blaOXA-51 (n = 78), blaOXA-23 (n = 62), and blaOXA-58 (n = 3). Interestingly, two clinical isolates harbored the rmtC 16S-RMTase gene. To the best of our knowledge, this is the first description of the presence of rmtC in A. baumannii.

Detection of qnrVC6, within a new genetic context, in an NDM-1-producing Citrobacter freundii clinical isolate from Uruguay.

OBJECTIVES: The objective of this study was to characterise the mechanisms underlying quinolone and oxyimino-cephalosporin resistance in a Citrobacter freundii clinical isolate obtained from the ICU in a university hospital in Uruguay. METHODS: Citrobacter freundii strain CF638 was isolated from a urine culture. Identification was performed using a VITEK®2 system, and antimicrobial susceptibility was established by MIC determination and disk diffusion assay. Resistance genes and mobile genetic elements were identified by PCR and sequencing. Plasmid transfer was assessed by conjugation and the plasmid size was estimated by S1-PFGE. Plasmid incompatibility (Inc) group and toxin-antitoxin systems were sought by PCR. RESULTS: Strain CF638 showed a multidrug-resistant profile, including resistance to carbapenems and quinolones. Transconjugant TcCF638, harbouring an ca. 200-kb IncA/C plasmid, also showed resistance to all ß-lactams (except aztreonam) and diminished susceptibility to ciprofloxacin. PCR was positive for blaNDM-1 and qnrVC in CF638 and TcCF638. Two different class 1 integrons were detected (In127 and In907). In127 featured the genetic array aadA2-ltr2. Conversely, complex In907 featured two variable regions (VRs); VR-1 consisted of aadB-blaOXA-10-aadA1cc, whereas VR-2 featured a qnrVC6 gene 108bp downstream from ISCR1 and 45bp upstream from qacEΔ1. Expression of qnrVC6 was due to a putative promoter region, detected using the Neural Network Promoter Prediction program. CONCLUSION: To the best of our knowledge, this constitutes the first report of qnrVC within a complex class 1 integron, as well as the first report of the occurrence of such a gene in an NDM-1-producing enterobacterial clinical isolate.