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151300.9190Occurrence and Characterization of NDM-1-Producing Shewanella spp. and Acinetobacter portensis Co-Harboring tet(X3) in a Chinese Dairy Farm. Bacteria with carbapenem or tigecycline resistance have been spreading widely among humans, animals and the environment globally, being great threats to public health. However, bacteria co-carrying drug resistance genes of carbapenem and tigecycline in Shewanella and Acinetobacter species remain to be investigated. Here, we detected nine bla(NDM-1)-carrying Shewanella spp. isolates as well as three A. portensis isolates co-harboring tet(X3) and bla(NDM-1) from seventy-two samples collected from a dairy farm in China. To explore their genomic characteristic and transmission mechanism, we utilized various methods, including PCR, antimicrobial susceptibility testing, conjugation experiment, whole-genome sequencing, circular intermediate identification and bioinformatics analysis. Clonal dissemination was found among three A. portensis, of which tet(X3) and bla(NDM-1) were located on a novel non-conjugative plasmid pJNE5-X3_NDM-1 (333,311 bp), and the circular intermediate ΔISCR2-tet(X3)-bla(NDM-1) was identified. Moreover, there was another copy of tet(X3) on the chromosome of A. portensis. It was verified that bla(NDM-1) could be transferred to Escherichia coli C600 from Shewanella spp. by conjugation, and self-transmissible IncA/C(2) plasmids mediated the transmission of bla(NDM-1) in Shewanella spp. strains. Stringent surveillance was warranted to curb the transmission of such vital resistance genes.202236290080
149210.9172Characterization of the tet(M)-bearing transposon Tn7125 of Escherichia coli strain A13 isolated from an intensive pig farm located in Henan province, China. BACKGROUND: Transposons carrying tet(M) in Gram-positive bacteria have been reported extensively, while there is a paucity of data on the transmission characteristics of tet(M) in Gram-negative bacteria. Therefore, the aim of this study was to investigate the genetic characteristics of the tet(M)-bearing transposon Tn7125, and to clarify the transmission mechanism of the plasmids pTA13-1 and pTA13-3 in Escherichia coli strain A13. METHODS: Plasmids from strain A13 and a corresponding transconjugant were determined by whole genome sequencing and analyzed using bioinformatics tools. The plasmids pTA13-1 and pTA13-3 of the transconjugant TA13 were characterized by S1-pulse-field gel electrophoresis, Southern hybridization, stability experiments, and direct competition assays. RESULTS: The conjugated IncF2:A6:B20 plasmid pTA13-1 co-transferred with the 41-kb plasmid pTA13-3, which carried no resistance genes; plasmid pTA13-2, which harbored the replication initiator PO111; and the IncX4 plasmid pTA13-4, which harbored the antibiotic resistance gene mcr-1. The novel IS26-bracked composite transposon Tn7125 was located on plasmid pTA13-1, which mainly consists of three resistance modules: IS26-ctp-lp-tet(M)-hp-IS406tnp, qac-aadA1-cmlA1-aadA2-DUF1010-dfrA12, and ∆ISVSa3-VirD-floR-LysR-ISVSa3. The plasmid pTA13-1 was highly stable in E. coli strain J53 with no fitness cost to the host or disadvantage in growth competition. CONCLUSION: Evolution of co-integrated transposons, such as Tn7125, may convey antibiotic resistance to a wide spectrum of hosts via the plasmids pTA13-1 and pTA13-3, which acts as an adaptable and mobile multidrug resistance reservoir to accelerate dissemination of other genes by co-selection, thereby posing a potentially serious barrier to clinical treatment regimens.202540639501
153120.9170Emergence of Plasmids Co-Harboring Carbapenem Resistance Genes and tmexCD2-toprJ2 in Sequence Type 11 Carbapenem Resistant Klebsiella pneumoniae Strains. OBJECTIVES: To characterize two plasmids co-harboring carbapenem resistance genes and tmexCD2-toprJ2 in carbapenem-resistant Klebsiella pneumoniae (CRKP) strains. METHODS: Two clinical CRKP strains were isolated and characterized by antimicrobial susceptibility testing, conjugation assays, whole-genome sequencing, and bioinformatics analysis. RESULTS: The two CRKP strains NB4 and NB5 were both resistant to imipenem, meropenem and tigecycline. Whole-genome sequencing revealed that two CRKP strains belonged to the ST11 type and carried multiple resistance genes. The tmexCD2-toprJ2 clusters in both strains were located on the IncFIB(Mar)-like/HI1B-like group of hybrid plasmids, which co-harbored the metallo-β-lactamase gene bla(NDM-1). In addition, the co-existence of bla(NDM-1) and bla(KPC-2) and the presence of tmexCD2-toprJ2 in CRKP strain NB5 was observed. CONCLUSIONS: In this study, tmexCD2-toprJ2 gene clusters were identified in two NDM-1-producing CRKP ST11 strains. These gene clusters will likely spread into clinical high-risk CRKP clones and exacerbate the antimicrobial resistance crisis. In addition, we detected the co-occurrence of bla(NDM-1), bla(KPC-2) and tmexCD2-toprJ2 in a single strain, which will undoubtedly accelerate the formation of a "superdrug resistant" bacteria. Hence, effective control measures should be implemented to prevent the further dissemination of such organisms in clinical settings.202235646740
152830.9162First Report of Coexistence of bla (SFO-1) and bla (NDM-1) β-Lactamase Genes as Well as Colistin Resistance Gene mcr-9 in a Transferrable Plasmid of a Clinical Isolate of Enterobacter hormaechei. Many antimicrobial resistance genes usually located on transferable plasmids are responsible for multiple antimicrobial resistance among multidrug-resistant (MDR) Gram-negative bacteria. The aim of this study is to characterize a carbapenemase-producing Enterobacter hormaechei 1575 isolate from the blood sample in a tertiary hospital in Wuhan, Hubei Province, China. Antimicrobial susceptibility test showed that 1575 was an MDR isolate. The whole genome sequencing (WGS) and comparative genomics were used to deeply analyze the molecular information of the 1575 and to explore the location and structure of antibiotic resistance genes. The three key resistance genes (bla (SFO-1), bla (NDM-1), and mcr-9) were verified by PCR, and the amplicons were subsequently sequenced. Moreover, the conjugation assay was also performed to determine the transferability of those resistance genes. Plasmid files were determined by the S1 nuclease pulsed-field gel electrophoresis (S1-PFGE). WGS revealed that p1575-1 plasmid was a conjugative plasmid that possessed the rare coexistence of bla (SFO-1), bla (NDM-1), and mcr-9 genes and complete conjugative systems. And p1575-1 belonged to the plasmid incompatibility group IncHI2 and multilocus sequence typing ST102. Meanwhile, the pMLST type of p1575-1 was IncHI2-ST1. Conjugation assay proved that the MDR p1575-1 plasmid could be transferred to other recipients. S1-PFGE confirmed the location of plasmid with molecular weight of 342,447 bp. All these three resistant genes were flanked by various mobile elements, indicating that the bla (SFO-1), bla (NDM-1), and mcr-9 could be transferred not only by the p1575-1 plasmid but also by these mobile elements. Taken together, we report for the first time the coexistence of bla (SFO-1), bla (NDM-1), and mcr-9 on a transferable plasmid in a MDR clinical isolate E. hormaechei, which indicates the possibility of horizontal transfer of antibiotic resistance genes.202134220761
150540.9160New insights on mcr-1-harboring plasmids from human clinical Escherichia coli isolates. Mobile colistin resistance (mcr) genes were described recently in Gram-negative bacteria including carbapenem-resistant Enterobacterales. There are ten mcr genes described in different Gram-negative bacteria, however, Escherichia coli harboring mcr-1 gene is by far the most frequent combination. In Argentina, mcr-1 gene was characterized only on plasmids belonging to IncI2 group. The aim of this work was to get new insights of mcr-1-harboring plasmids from E. coli. Eight E. coli isolates from a larger collection of 192 clinical E. coli isolates carrying the mcr-1 gene were sequenced using next generation technologies. Three isolates belonged to ST131 high-risk clone, and five to single ST, ST38, ST46, ST226, ST224, and ST405. Eight diverse mcr-1-harboring plasmids were analyzed: IncI2 (1), IncX4 (3), IncHI2/2A (3) and a hybrid IncFIA/HI1A/HI1B (1) plasmid. Plasmids belonging to the IncI2 (n = 1) and IncX4 (n = 3) groups showed high similarity with previously described plasmids. Two IncHI2/HI2A plasmids, showed high identity between them, while the third, showed several differences including additional resistance genes like tet(A) and floR. One IncFIA/H1A/H1B hybrid plasmid was characterized, highly similar to pSRC27-H, a prototype plasmid lacking mcr genes. mcr-1.5 variant was found in four plasmids with three different Inc groups: IncI2, IncHI2/HI2A and the hybrid FIA/HI1A/HI1B plasmid. mcr-1.5 variant is almost exclusively described in our country and with a high frequency. In addition, six E. coli isolates carried three allelic variants codifying for CTX-M-type extended-spectrum-β-lactamases: blaCTX-M-2 (3), blaCTX-M-65 (2), and blaCTX-M-14 (1). It is the first description of mcr-1 harboring plasmids different to IncI2 group in our country. These results represents new insights about mcr-1 harboring plasmids recovered from E. coli human samples from Argentina, showing different plasmid backbones and resistance gene combinations.202438408071
138750.9158Whole-Genome Characterisation of ESBL-Producing E. coli Isolated from Drinking Water and Dog Faeces from Rural Andean Households in Peru. E. coli that produce extended-spectrum β-lactamases (ESBLs) are major multidrug-resistant bacteria. In Peru, only a few reports have characterised the whole genome of ESBL enterobacteria. We aimed to confirm the identity and antimicrobial resistance (AMR) profile of two ESBL isolates from dog faeces and drinking water of rural Andean households and determine serotype, phylogroup, sequence type (ST)/clonal complex (CC), pathogenicity, virulence genes, ESBL genes, and their plasmids. To confirm the identity and AMR profiles, we used the VITEK(®)2 system. Whole-genome sequencing (WGS) and bioinformatics analysis were performed subsequently. Both isolates were identified as E. coli, with serotypes -:H46 and O9:H10, phylogroups E and A, and ST/CC 5259/- and 227/10, respectively. The isolates were ESBL-producing, carbapenem-resistant, and not harbouring carbapenemase-encoding genes. Isolate 1143 ST5259 harboured the astA gene, encoding the EAST(1) heat-stable toxin. Both genomes carried ESBL genes (bla(EC-15), bla(CTX-M-8), and bla(CTX-M-55)). Nine plasmids were detected, namely IncR, IncFIC(FII), IncI, IncFIB(AP001918), Col(pHAD28), IncFII, IncFII(pHN7A8), IncI1, and IncFIB(AP001918). Finding these potentially pathogenic bacteria is worrisome given their sources and highlights the importance of One-Health research efforts in remote Andean communities.202235625336
200260.9157IncHI1 plasmids mediated the tet(X4) gene spread in Enterobacteriaceae in porcine. The tigecycline resistance gene tet(X4) was widespread in various bacteria. However, limited information about the plasmid harboring the tet(X4) gene spread among the different species is available. Here, we investigated the transmission mechanisms of the tet(X4) gene spread among bacteria in a pig farm. The tet(X4) positive Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Enterobacter hormaeche were identified in the same farm. The whole genome sequencing (WGS) analysis showed that the K. pneumoniae belonged to ST727 (n = 11) and ST3830 (n = 1), E. cloacae and E. hormaeche belonged to ST524 (n = 1) and ST1862 (n = 1). All tet(X4) genes were located on the IncHI1 plasmids that could be conjugatively transferred into the recipient E. coli C600 at 30°C. Moreover, a fusion plasmid was identified that the IncHI1 plasmid recombined with the IncN plasmid mediated by ISCR2 during the conjugation from strains B12L to C600 (pB12L-EC-1). The fusion plasmid also has been discovered in a K. pneumoniae (K1L) that could provide more opportunities to spread antimicrobial resistance genes. The tet(X4) plasmids in these bacteria are derived from the same plasmid with a similar structure. Moreover, all the IncHI1 plasmids harboring the tet(X4) gene in GenBank belonged to the pST17, the newly defined pMLST. The antimicrobial susceptibility testing was performed by broth microdilution method showing the transconjugants acquired the most antimicrobial resistance from the donor strains. Taken together, this report provides evidence that IncHI1/pST17 is an important carrier for the tet(X4) spread in Enterobacteriaceae species, and these transmission mechanisms may perform in the environment.202337065147
153670.9156Complete Genetic Analysis of Plasmids Carried by Two Nonclonal bla(NDM-5)- and mcr-1-Bearing Escherichia coli Strains: Insight into Plasmid Transmission among Foodborne Bacteria. Our objective was to characterize the genetic features of plasmids harbored by two genetically related, MCR-1 and NDM-5-producing Escherichia coli strains recovered from a chicken meat sample. The genetic profiles of all plasmids harbored by the two test strains, namely, 1106 and 1107, were determined by whole-genome sequencing, S1-pulsed-field gel electrophoresis (PFGE), Southern hybridization, and bioinformatics analysis. The transferability of plasmids harbored by the two strains was assessed by filter mating assay. Strains 1106 and 1107 were resistant to almost all the antibiotics, including colistin and fosfomycin, but remained susceptible to amikacin and tigecycline. The plasmids of p1107-NDM-5 and p1106-NDM-5 both contain a class I integron which lacks the ISAba125 element. The backbone of p1106-IncFII exhibited a high degree of similarity with that of p1106-NDM-5 and p1107-NDM-5, implying that events of plasmid fusion and resolution were involved in the formation of the two plasmids. The plasmids p1106-IncHI2MCR and p1107-IncHI2MCR belong to an IncHI2 replicon type, with three copies of ISApl1 being observed in p1106-IncHI2MCR, implying that the mcr-1 gene was transferable among bacteria that reside in the same food matrix. In this study, p1106-IncFIB, p1107-99K, p1107-111K, and p1107-118K were all found to be phage-like plasmids, with p1106-IncFIB and p1107-118K containing several virulence genes, including iroBCDEN, iucABCD, sitABCD, hlyF, and iss. Surprisingly, resistance genes such as aph(3')-Ia, sul3, and aac(3')-IId could also be found in p1107-118K, but resistance genes were not detected in other phage-like plasmids. In conclusion, enhanced surveillance is required to monitor and control the dissemination of various resistance determinants among foodborne pathogens. IMPORTANCE Carbapenem and colistin are last-resort antibiotics used to treat serious clinical infections caused by multidrug-resistant (MDR) bacterial pathogens. Plasmids encoding resistance to carbapenems and colistin have been reported in clinical pathogens in recent years, and yet few studies reported cocarriage of mcr and bla(NDM) genes in Escherichia coli strains of food origin. How plasmids encoding these two important resistance determinants are being evolved and transmitted in bacterial pathogens is not well understood. In this study, we investigated the genetic features of plasmids harbored by two nonclonal, mcr-1- and bla(NDM-5)-bearing E. coli strains (1106 and 1107) recovered from a fresh chicken meat sample to understand and provide evidence of the level and dynamics of MDR plasmid transmission. Our data confirmed that active plasmid fusion and resolution events were involved in the formation of plasmids that harbor multiple resistance genes, which provide insights into the further control of plasmid evolution in bacterial pathogens.202134468190
523580.9155Draft genome sequences of rare Lelliottia nimipressuralis strain MEZLN61 and two Enterobacter kobei strains MEZEK193 and MEZEK194 carrying mobile colistin resistance gene mcr-9 isolated from wastewater in South Africa. OBJECTIVES: Antimicrobial-resistant bacteria of the order Enterobacterales are emerging threats to global public and animal health, leading to morbidity and mortality. The emergence of antimicrobial-resistant, livestock-associated pathogens is a great public health concern. The genera Enterobacter and Lelliottia are ubiquitous, facultatively anaerobic, motile, non-spore-forming, rod-shaped Gram-negative bacteria belonging to the Enterobacteriaceae family and include pathogens of public health importance. Here, we report the first draft genome sequences of a rare Lelliottia nimipressuralis strain MEZLN61 and two Enterobacter kobei strains MEZEK193 and MEZEK194 in Africa. METHODS: The bacteria were isolated from environmental wastewater samples. Bacteria were cultured on nutrient agar, and the pure cultures were subjected to whole-genome sequencing. Genomic DNA was sequenced using an Illumina MiSeq platform. Generated reads were trimmed and subjected to de novo assembly. The assembled contigs were analysed for virulence genes, antimicrobial resistance genes, and extra-chromosomal plasmids, and multilocus sequence typing was performed. To compare the sequenced strains with other, previously sequenced E. kobei and L. nimipressuralis strains, available raw read sequences were downloaded, and all sequence files were treated identically to generate core genome bootstrapped maximum likelihood phylogenetic trees. RESULTS: Whole-genome sequencing analyses identified strain MEZLN61 as L. nimipressuralis and strains MEZEK193 and MEZEK194 as E. kobei. MEZEK193 and MEZEK194 carried genes encoding resistance to fosfomycin (fosA), beta-lactam antibiotics (bla(ACT-9)), and colistin (mcr-9). Additionally, MEZEK193 harboured nine different virulence genes, while MEZEK194 harboured eleven different virulence genes. The phenotypic analysis showed that L. nimipressuralis strain MEZLN61 was susceptible to colistin (2 μg/mL), while E. kobei MEZEK193 (64 μg/mL) and MEZEK194 (32 μg/mL) were resistant to colistin. CONCLUSION: The genome sequences of strains L. nimipressuralis MEZLN6, E. kobei MEZEK193, and E. kobei MEZEK194 will serve as a reference point for molecular epidemiological studies of L. nimipressuralis and E. kobei in Africa. In addition, this study provides an in-depth analysis of the genomic structure and offers important information that helps clarify the pathogenesis and antimicrobial resistance of L. nimipressuralis and E. kobei. The detection of mcr-9, which is associated with very low-level colistin resistance in Enterobacter species, is alarming and may indicate the undetected dissemination of mcr genes in bacteria of the order Enterobacterales. Continuous monitoring and surveillance of the prevalence of mcr genes and their associated phenotypic changes in clinically important pathogens and environmentally associated bacteria is necessary to control and prevent the spread of colistin resistance.202336948496
138890.9154Snapshot Study of Whole Genome Sequences of Escherichia coli from Healthy Companion Animals, Livestock, Wildlife, Humans and Food in Italy. Animals, humans and food are all interconnected sources of antimicrobial resistance (AMR), allowing extensive and rapid exchange of AMR bacteria and genes. Whole genome sequencing (WGS) was used to characterize 279 Escherichia coli isolates obtained from animals (livestock, companion animals, wildlife), food and humans in Italy. E. coli predominantly belonged to commensal phylogroups B1 (46.6%) and A (29%) using the original Clermont criteria. One hundred and thirty-six sequence types (STs) were observed, including different pandemic (ST69, ST95, ST131) and emerging (ST10, ST23, ST58, ST117, ST405, ST648) extraintestinal pathogenic Escherichia coli (ExPEC) lineages. Eight antimicrobial resistance genes (ARGs) and five chromosomal mutations conferring resistance to highest priority critically important antimicrobials (HP-CIAs) were identified (qnrS1, qnrB19, mcr-1, bla(CTX-M1,15,55), bla(CMY-2), gyrA/parC/parE, ampC and pmrB). Twenty-two class 1 integron arrangements in 34 strains were characterized and 11 ARGs were designated as intI1 related gene cassettes (aadA1, aadA2, aadA5, aad23, ant2_Ia, dfrA1, dfrA7, dfrA14, dfrA12, dfrA17, cmlA1). Notably, most intI1 positive strains belonged to rabbit (38%) and poultry (24%) sources. Three rabbit samples carried the mcr-1 colistin resistance gene in association with IS6 family insertion elements. Poultry meat harbored some of the most prominent ExPEC STs, including ST131, ST69, ST10, ST23, and ST117. Wildlife showed a high average number of virulence-associated genes (VAGs) (mean = 10), mostly associated with an ExPEC pathotype and some predominant ExPEC lineages (ST23, ST117, ST648) were identified.202033172096
1514100.9153Widespread prevalence and molecular epidemiology of tet(X4) and mcr-1 harboring Escherichia coli isolated from chickens in Pakistan. The emergence and spread of plasmid-mediated tigecycline resistance gene tet(X4) and colistin resistance gene mcr-1 in Escherichia coli (E. coli) pose a potential threat to public health, due to the importance of colistin and tigecycline for treating serious clinical infections. However, the characterization of bacteria coharboring both genes was few reported. Here, we described the molecular epidemiology of tet(X4) and mcr-1 harboring E. coli strains of chicken origin in Pakistan, with methods including PCR, antimicrobial susceptibility testing, DNA transfer assays, plasmid replicon typing, whole-genome sequencing and bioinformatics analysis. The tet(X4) gene was identified in 36 isolates exhibiting high levels of tigecycline resistance (MICs, 16-128 mg/L). Worryingly, 24 of the 36 tet(X4)-bearing isolates were confirmed as colistin resistance, positive for plasmid-borne mcr-1. We observed the prevalence of tet(X4)-bearing IncFII plasmid with mcr-1-bearing IncI2 plasmid in 12 E. coli isolates, with a high co-transfer frequency except for one strain PK8233, in which tet(X4)- and mcr-1-bearing plasmids were non-transferable. Coexistence of tet(X4)-bearing IncFII plasmid with mcr-1-carrying multidrug-resistant (MDR) IncHI2 plasmid was also identified in 10 E. coli isolates, and a relatively low co-transfer frequency was obtained except PK8575, in which mcr-1 was non-transferable. The transferability of pPK8275-tetX in PK8275 and pPK8233-tetX in PK8233, that could transfer from E. coli J53 to C600 by conjugation, was interfered by certain factors in PK8275 and PK8233. This may provide new insights to prevent and control the spread of antibiotic resistance genes. Two strains were reported to co-carry tet(X4)-positive IncQ1 plasmid and mcr-1-positive IncI2 plasmid. Convergence of tet(X4) and mcr-1 genes in E. coli by conjugative or mobilizable plasmids may lead to potentially widespread transmission of such resistance genes, which may incur antibiotic-resistance crisis globally.202234599956
5701110.9152An Acinetobacter non-baumannii Population Study: Antimicrobial Resistance Genes (ARGs). Acinetobacter non-baumannii species are becoming common etiologic agents of nosocomial infections. Furthermore, clinical isolates belonging to this group of bacteria are usually resistant to one or more antibiotics. The current information about antibiotic resistance genes in the different A. non-baumannii species has not yet been studied as a whole. Therefore, we did a comparative study of the resistomes of A. non-baumannii pathogens based on information available in published articles and genome sequences. We searched the available literature and sequences deposited in GenBank to identify the resistance gene content of A. calcoaceticus, A. lwoffii, A. junii, A. soli, A. ursingii, A. bereziniae, A. nosocomialis, A. portensis, A. guerrae, A. baylyi, A. calcoaceticus, A. disperses, A. johnsonii, A. junii, A. lwoffii, A. nosocomialis, A. oleivorans, A. oryzae, A. pittii, A. radioresistens, and A. venetianus. The most common genes were those coding for different β-lactamases, including the carbapenemase genes bla (NDM-1) and bla (OXA-58). A. pittii was the species with the most β-lactamase resistance genes reported. Other genes that were commonly found include those encoding some aminoglycoside modifying enzymes, the most common being aph(6)-Id, ant( 3 ″ )-IIa, and aph( 3 ″ )-Ib, and efflux pumps. All or part of the genes coding for the AdeABC, AdeFGH, and AdeIJK efflux pumps were the most commonly found. This article incorporates all the current information about A. non-baumannii resistance genes. The comparison of the different resistomes shows that there are similarities in the genes present, but there are also significant differences that could impact the efficiency of treatments depending on the etiologic agent. This article is a comprehensive resource about A. non-baumannii resistomes.202033375352
1537120.9151Occurrence and mechanisms of tigecycline resistance in carbapenem- and colistin-resistant Klebsiella pneumoniae in Thailand. Tigecycline has been regarded as one of the most important last-resort antibiotics for the treatment of infections caused by extensively drug-resistant (XDR) bacteria, particularly carbapenem- and colistin-resistant Klebsiella pneumoniae (C-C-RKP). However, reports on tigecycline resistance have been growing. Overall, ~ 4000 K. pneumoniae clinical isolates were collected over a five-year period (2017-2021), in which 240 isolates of C-C-RKP were investigated. Most of these isolates (91.7%) were resistant to tigecycline. Notably, a high-risk clone of ST16 was predominantly identified, which was associated with the co-harboring of bla(NDM-1) and bla(OXA-232) genes. Their major mechanism of tigecycline resistance was the overexpression of efflux pump acrB gene and its regulator RamA, which was caused by mutations in RamR (M184V, Y59C, I141T, A28T, C99/C100 insertion), in RamR binding site (PI) of ramA gene (C139T), in MarR (S82G), and/or in AcrR (L154R, R13Q). Interestingly, four isolates of ST147 carried the mutated tet(A) efflux pump gene. To our knowledge, this is the first report on the prevalence and mechanisms of tigecycline resistance in C-C-RKP isolated from Thailand. The high incidence of tigecycline resistance observed among C-C-RKP in this study reflects an ongoing evolution of XDR bacteria against the last-resort antibiotics, which demands urgent action.202438433246
1517130.9151Co-occurrence of blaNDM-1, rmtC, and mcr-9 in multidrug-resistant Enterobacter kobei strain isolated from an infant with urinary tract infection. OBJECTIVES: The co-emergence of mcr and carbapenem resistance genes in Gram-negative bacteria is a serious problem. This study aims to clarify the genetic characteristic of one novel multidrug-resistant Enterobacter kobei EC1382 with mcr-9 causing urinary tract inflammation in an infant. METHODS: Antimicrobial drug susceptibility testing was performed for this isolate using the broth microdilution method. Whole-genome sequencing was performed using the Illumina PacBio RS II platform and HiSeq platform, and the antimicrobial resistance genes, mobile elements, and plasmid replicon types were identified. Conjugation analysis was performed using Escherichia coli C600 as recipients. RESULTS: Enterobacter kobei EC1382 was resistant to carbapenem, aminoglycoside, and cephalosporin. Twenty-five antimicrobial resistance genes were identified, including genes conferring resistance to carbapenem (blaNDM-1), colistin (mcr-9), and aminoglycosides (rmtC). The blaNDM-1 gene, accompanied by bleMBL and rmtC located downstream of an ISCR14 element, was detected in the IncFII(Yp) type plasmid pEC1382-2. Interestingly, although E. kobei EC1382 was susceptible to colistin, it had three identical mcr-9 genes (two in the chromosome and one in the IncHI2-type plasmid pEC1382-1). The backbone (∼12.2-kb genetic fragment) of these mcr-9 (flanked by IS903B and IS481-IS26) regions were conserved in this strain, and they were found to be present in various bacteria as three types, implying a silent distribution. CONCLUSIONS: To the best of our knowledge, this is the first study to demonstrate the coexistence of blaNDM-1, rmtC, and mcr-9 in E. kobei. The silent prevalence of mcr-9 in bacteria may be a threat to public health.202337062506
1737140.9150Isolation and Characterisation of Human-Derived bla(KPC-3)-Producing Salmonella enterica Serovar Rissen in 2018. In this study, we describe a Salmonella enterica serovar (S.) Rissen strain with a reduced susceptibility to meropenem, isolated from a urinary infection in an 89-year-old woman in 2018 during activity surveillance in Italy (Enter-Net Italia). The genomic characteristics, pathogenicity, and antimicrobial resistance mechanisms were investigated via a genomic approach. Antimicrobial susceptibility testing revealed a "susceptible, increased exposure" phenotype to meropenem in the S. Rissen strain (4_29_19). Whole-genome sequencing (WGS) was performed using both the NovaSeq 6000 S4 PE150 XP platform (Illumina, San Diego, CA, USA) and MinION (Oxford Nanopore). The S. Rissen 4_29_19 strain harboured two plasmids: a pKpQIL-like plasmid carrying the bla(KPC-3) resistance gene in a Tn4401a transposon (pKPC_4_29_19), and a ColE-like plasmid (p4_4_29_19) without resistance genes, highly prevalent among Enterobacterales. Comparative analysis revealed that the pKPC_4_29_19 plasmid was highly related to the pKpQIL reference plasmid (GU595196), with 57% coverage and 99.96% identity, but lacking a region of about 30 kb, involving the FIIK(2) replicon region and the entire transfer locus, causing the loss of its ability to conjugate. To our knowledge, this is the first time that a pKpQIL-like plasmid, carrying bla(KPC-3), highly diffused in Klebsiella pneumoniae strains, has been identified in a Salmonella strain in our country. The acquisition of bla(KPC) genes by Salmonella spp. is extremely rare, and is reported only sporadically. In zoonotic bacteria isolated from humans, the presence of a carbapenem resistance gene carried by mobile genetic elements, usually described in healthcare-associated infection bacteria, represents an important concern for public health.202337760674
1413150.9149Occurrence of Carbapenemases, Extended-Spectrum Beta-Lactamases and AmpCs among Beta-Lactamase-Producing Gram-Negative Bacteria from Clinical Sources in Accra, Ghana. Beta-lactamase (β-lactamase)-producing Gram-negative bacteria (GNB) are of public health concern due to their resistance to routine antimicrobials. We investigated the antimicrobial resistance and occurrence of carbapenemases, extended-spectrum β-lactamases (ESBLs) and AmpCs among GNB from clinical sources. GNB were identified using matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDITOF-MS). Antimicrobial susceptibility testing was performed via Kirby-Bauer disk diffusion and a microscan autoSCAN system. β-lactamase genes were determined via multiplex polymerase chain reactions. Of the 181 archived GNB analyzed, Escherichia coli and Klebsiella pneumoniae constituted 46% (n = 83) and 17% (n = 30), respectively. Resistance to ampicillin (51%), third-generation cephalosporins (21%), and ertapenem (21%) was observed among the isolates, with 44% being multi-drug resistant (MDR). β-lactamase genes such as AmpCs ((bla(FOX-M) (64%) and bla(DHA-M) and bla(EDC-M) (27%)), ESBLs ((bla(CTX-M) (81%), other β-lactamase genes bla(TEM) (73%) and bla(SHV) (27%)) and carbapenemase ((bla(OXA-)(48) (60%) and bla(NDM) and bla(KPC) (40%)) were also detected. One K. pneumoniae co-harbored AmpC (bla(FOX-M) and bla(EBC-M)) and carbapenemase (bla(KPC) and bla(OXA-)(48)) genes. bla(OXA-)(48) gene was detected in one carbapenem-resistant Acinetobacter baumannii. Overall, isolates were resistant to a wide range of antimicrobials including last-line treatment options. This underpins the need for continuous surveillance for effective management of infections caused by these pathogens in our settings.202337370334
1408160.9149Six Extensively Drug-Resistant Bacteria in an Injured Soldier, Ukraine. Blood and surveillance cultures from an injured service member from Ukraine grew Acinetobacter baumannii, Klebsiella pneumoniae, Enterococcus faecium, and 3 distinct Pseudomonas aeruginosa strains. Isolates were nonsusceptible to most antibiotics and carried an array of antibiotic resistant genes, including carbapenemases (bla(IMP-1), bla(NDM-1), bla(OXA-23), bla(OXA-48), bla(OXA-72)) and 16S methyltransferases (armA and rmtB4).202337406356
1532170.9148Identification of TMexCD-TOprJ-producing carbapenem-resistant Gram-negative bacteria from hospital sewage. Carbapenems and tigecycline are crucial antimicrobials for the treatment of gram-negative bacteria infections. Recently, a novel resistance-nodulation-division (RND) efflux pump gene cluster, tmexCD-toprJ, which confers resistance to tigecycline, has been discovered in animals and clinical isolates. It was reported that hospital sewage could act as a reservoir for gram-negative bacteria with high antimicrobial resistance genes. In this study, we analyzed 84 isolates of carbapenem-resistant gram-negative bacteria (CR-GNB) from hospital sewage, and identified five isolates of TMexCD-ToprJ-producing CR-GNB, including one Raoultella ornithinolytica isolate and four Pseudomonas spp. isolates. All these five isolates carried at least one carbapenem resistance gene and were resistant to multiple antibiotics. Multiple tmexCD-toprJ clusters were detected, including tmexC2D2-toprJ2, tmexC3D3-toprJ3, tmexC3.2D3.3-toprJ1b and tmexC3.2D3-toprJ1b. Among these clusters, the genetic construct of tmexC3.2D3-toprJ1b showed 2-fold higher minimum inhibitory concentration (MIC) of tigecycline than other three variants. In addition, it was found that the tmexCD-toprJ gene cluster was originated from Pseudomonas spp. and mainly located on Tn6855 variants inserted in the same umuC-like genes on chromosomes and plasmids. This unit co-localized with bla(IMP) or bla(VIM) on IncHI5-, Inc(pJBCL41)- and Inc(pSTY)-type plasmids in the five isolates of TMCR-GNB. The IncHI5- and Inc(pSTY)-type plasmids had the ability to conjugal transfer to E. coli J53 and P. aeruginosa PAO1, highlighting the potential risk of transfer of tmexCD-toprJ from Pseudomonas spp. to Enterobacterales. Importantly, genomic analysis showed that similar tmexCD-toprJ-harboring IncHI5 plasmids were also detected in human samples, suggesting transmission between environmental and human sectors. The emergence of TMCR-GNB from hospital sewage underscores the need for ongoing surveillance of antimicrobial resistance genes, particularly the novel resistance genes such as the tmexCD-toprJ gene clusters in the wastewater environment.202337480594
1511180.9147Characterization of an Extensively Drug-Resistant Salmonella Kentucky ST198 Co-Harboring cfr, mcr-1 and tet(A) Variant from Retail Chicken Meat in Shanghai, China. The emergence of extensively drug-resistant (XDR) foodborne pathogens poses grave threats to food safety. This study characterizes the genome of an XDR Salmonella Kentucky isolate (Sal23C1) co-harboring cfr, mcr-1 and tet(A) from Shanghai chicken meat in 2022, which was the only isolate co-harboring these three key resistance genes among 502 screened Salmonella isolates. Genomic analysis revealed that the multidrug resistance gene cfr, which confers resistance to phenicols, lincosamides, oxazolidinones, pleuromutilins and streptogramin A, was identified within a Tn3-IS6-cfr-IS6 structure on the transferable plasmid p3Sal23C1 (32,387 bp), showing high similarity to the Citrobacter braakii plasmid pCE32-2 (99% coverage, 99.98% identity). Concurrently, the mcr-1 gene resided in a pap2-mcr-1 structure on the transferable IncI2 plasmid p2Sal23C1 (63,103 bp). Notably, both genes could be co-transferred to recipient bacteria via conjugative plasmids at frequencies of (1.15 ± 0.98) × 10(-6). Furthermore, a novel ~79 kb multidrug resistance region (MRR) chromosomally inserted at the bcfH locus was identified, carrying fosA3, mph(A), rmtB, qnrS1 and bla(CTX-M-55). Additionally, a novel Salmonella Genomic Island 1 variant (SGI1-KI) harbored aadA7, qacEΔ1, sul1 and the tet(A) variant. The acquisition of these antibiotic resistance genes in this isolate enhanced bacterial resistance to 21 antimicrobials, including resistance to the critical last-resort antibiotics tigecycline and colistin, which left virtually no treatment options for potential infections. Taken together, this is the first comprehensive genomic report of an XDR poultry-derived Salmonella Kentucky isolate co-harboring cfr, mcr-1 and the tet(A) variant. The mobility of these resistance genes, facilitated by IS6 elements and conjugative plasmids, underscores significant public health risks associated with such isolates in the food chain.202540941142
2003190.9147Characterization of an Escherichia coli Isolate Coharboring the Virulence Gene astA and Tigecycline Resistance Gene tet(X4) from a Dead Piglet. tet(X4) is the critical resistance gene for tigecycline degradation that has been continually reported in recent years. In particular, pathogenic bacteria carrying tet(X4) are a severe threat to human health. However, information describing Escherichia coli coharboring tet(X4) with virulence genes is limited. Here, we isolated an E. coli strain coharboring tet(X4) and the heat-stable toxin gene astA from a dead piglet. The strain named 812A1-131 belongs to ST10. The genome was sequenced using the Nanopore and Illumina platforms. The virulence genes astA and tet(X4) are located on the chromosome and in the IncHI1-type plasmid p812A1-tetX4-193K, respectively. The plasmid could be conjugatively transferred to recipient E. coli J53 with high frequency. In vivo experiments showed that strain 812A1-131 is pathogenic to Galleria mellonella and could colonize the intestines of mice. In summary, pathogenic E. coli could receive a plasmid harboring the tet(X4) gene, which can increase the difficulty of treatment. The prevalence and transmission mechanisms of pathogenic bacteria coharboring the tet(X4) gene need more attention.202337513750