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299300.9259Antibiotic resistant zoonotic bacteria in Irrawaddy squirrel (Callosciurus pygerythrus). Irrawaddy squirrel (Callosciurus pygerythrus) may play an important role in the transmission of zoonotic bacteria, but little is known about the carriage of zoonotic bacteria in this common frugivorous rodent in Bangladesh. We aimed to investigate the presence of common zoonotic bacterial pathogens in Irrawaddy squirrel in the southeast part of Bangladesh. A total of 27 rectal and 27 oro-nasal swabs were collected from 27 healthy wild Irrawaddy squirrels. Four common zoonotic bacteria were isolated following routine laboratory procedures, and were identified based on colony morphology, and biochemical and staining properties. The pathogenic potential of the identified bacteria was confirmed by detection of virulence genes by PCR. All isolates were subjected to antimicrobial susceptibility test against seven antibiotics from six generic groups which are commonly used in human and veterinary medicine in Bangladesh. The prevalence of Escherichia coli, Salmonella spp., Yersinia spp. and Staphylococcus spp. was 44.4% (95% CI, 32.0-57.6), 13% (95% CI, 6.1-24.7), 44.4% (95% CI, 32.0-57.6), and 72.2% (95% CI, 59.0-82.5), respectively. We identified potential zoonotic virulence genes in all of these four bacterial species. Antimicrobial susceptibility testing revealed the presence of several multidrug resistant bacterial strains in squirrels. To the best of our knowledge, this is the first report in Bangladesh of the detection of antibiotic resistant zoonotic bacteria in Irrawaddy squirrels. The findings underpin the role of Irrawaddy squirrel as a source of pathogenic antibiotic resistant bacteria, consequently, fruit rejected because of squirrel consumption and squirrel-bites deserve more concern than previously.201930488592
299810.9182Membrane vesicles derived from Enterococcus faecalis promote the co-transfer of important antibiotic resistance genes located on both plasmids and chromosomes. BACKGROUND: Bacterial membrane vesicles (BMVs) are novel vehicles of antibiotic resistance gene (ARG) transfer in Gram-negative bacteria, but their role in the spread of ARGs in Gram-positive bacteria has not been defined. The purpose of this study was to evaluate the role of MVs in the transmission of antimicrobial resistance in Gram-positive bacteria. METHODS: A linezolid-resistant Enterococcus faecalis CQ20 of swine origin was selected as the donor strain. Linezolid-susceptible E. faecalis SC032 of human origin, Enterococcus faecium BM4105 and Escherichia coli were selected as recipient strains. The presence of plasmids (pCQ20-1 and pCQ20-2) and an optrA-carrying transposon Tn6674 in CQ20, MVs and vesiculants was verified by WGS or PCR. MVs were isolated with density gradient centrifugation, and MV-mediated transformation was performed to assess the horizontal transferability of MVs. The MICs for CQ20 and its vesiculants were determined by the broth microdilution method. RESULTS: CQ20-derived MVs (CQ20-MV) were isolated, and PCR identified the presence of two plasmids and the optrA gene in the CQ20-MVs. MV-mediated transformation to E. faecalis SC032 and E. faecium BM4105 was successfully performed, and the WGS data also showed that both plasmids pCQ20-1 and pCQ20-2 and optrA-carrying transposon Tn6674 were transferred to E. faecalis SC032 and E. faecium BM4105, but failed for E. coli. Additionally, vesiculants that had acquired ARGs still had the ability to spread these genes via MVs. CONCLUSIONS: To our knowledge, this is the first report of MV-mediated co-transfer of ARG-carrying plasmids and transposons in the Gram-positive bacterium E. faecium.202438109479
540720.9175Resistance mechanisms and tedizolid susceptibility in clinical isolates of linezolid-resistant bacteria in Japan. OBJECTIVES: Studies combining linezolid resistance mechanisms and tedizolid susceptibility in linezolid-resistant clinical isolates are scarce. This study investigated the linezolid resistance mechanisms and tedizolid susceptibility of linezolid-resistant strains isolated clinically in Japan. METHODS: We analysed 25 linezolid-resistant strains of Enterococcus faecium and Enterococcus faecalis isolated from Japanese hospitals between 2015 and 2021. MICs of linezolid and tedizolid were determined using the agar plate dilution method. Each 23S rRNA copy was amplified by PCR, sequenced and analysed for mutations. The linezolid resistance genes cfr, poxtA, optrA, fexA and fexB were also detected by PCR. RESULTS: Drug susceptibility tests revealed that five linezolid-resistant E. faecium isolates had low (≤1 mg/L) tedizolid MICs. Resistance mechanisms included the G2576T mutation in 23S rRNA, the T2504A mutation and the resistance genes optrA, fexA and fexB. The T2504A mutation was identified in one E. faecium isolate, which exhibited linezolid and tedizolid MICs of 64 and 32 mg/L, respectively. CONCLUSIONS: Some linezolid-resistant isolates demonstrated low (≤1 mg/L) tedizolid MICs. To determine whether tedizolid susceptibility testing should be performed on linezolid-resistant isolates, more linezolid-resistant isolates should be collected and tested for tedizolid MICs. Tedizolid MICs were 2-3 doubling dilutions lower than linezolid MICs. The results of this study suggest that future research should investigate whether the T2504A mutation contributes to tedizolid resistance. To our knowledge, this is the first study to report tedizolid susceptibility in E. faecium with the T2504A mutation and in isolate harbouring this mutation.202540463587
50330.9175Interaction of the chromosomal Tn 551 with two thermosensitive derivatives, pS1 and p delta D, of the plasmid pI9789 in Staphylococcus aureus. The plasmid pI9789::Tn552 carries genes conferring resistance to penicillins and to cadmium, mercury and arsenate ions. The presence of Tn551 at one location in the chromosome of Staphylococcus aureus enhances the frequency of suppression of thermosensitivity of replication of the plasmids pS1 and p delta D which are derivatives of pI9789::Tn552. Bacteriophage propagated on the bacteria in which thermosensitivity of replication had been suppressed was used to transduce cadmium resistance to S. aureus PS80N. The cadmium-resistant transductants obtained carried plasmid pS1 or p delta D with a copy of Tn551 inserted into a specific site on pS1 but into several different sites on p delta D. The possible mechanisms of the suppression are discussed.19957758929
305740.9167An Enterobacter plasmid as a new genetic background for the transposon Tn1331. BACKGROUND: Genus Enterobacter includes important opportunistic nosocomial pathogens that could infect complex wounds. The presence of antibiotic resistance genes in these microorganisms represents a challenging clinical problem in the treatment of these wounds. In the authors' screening of antibiotic-resistant bacteria from complex wounds, an Enterobacter species was isolated that harbors antibiotic-resistant plasmids conferring resistance to Escherichia coli. The aim of this study was to identify the resistance genes carried by one of these plasmids. METHODS: The plasmids from the Enterobacter isolate were propagated in E. coli and one of the plasmids, designated as pR23, was sequenced by the Sanger method using fluorescent dyeterminator chemistry on a genetic analyzer. The assembled sequence was annotated by search of the GenBank database. RESULTS: Plasmid pR23 is composed of the transposon Tn1331 and a backbone plasmid that is identical to the plasmid pPIGDM1 from Enterobacter agglomerans. The multidrug-resistance transposon Tn1331, which confers resistance to aminoglycoside and beta lactam antibiotics, has been previously isolated only from Klebsiella. The Enterobacter plasmid pPIGDM1, which carries a ColE1-like origin of replication and has no apparent selective marker, appears to provide a backbone for propagation of Tn1331 in Enterobacter. The recognition sequence of Tn1331 transposase for insertion into pPIGDM1 is the pentanucleotide TATTA, which occurs only once throughout the length of this plasmid. CONCLUSION: Transposition of Tn1331 into the Enterobacter plasmid pPIGDM1 enables this transposon to propagate in this Enterobacter. Since Tn1331 was previously isolated only from Klebsiella, this report suggests horizontal transfer of this transposon between the two bacterial genera.201122259249
544050.9163Molecular structure and evolution of the conjugative multiresistance plasmid pRE25 of Enterococcus faecalis isolated from a raw-fermented sausage. Plasmid pRE25 from Enterococcus faecalis transfers resistances against kanamycin, neomycin, streptomycin, clindamycin, lincomycin, azithromycin, clarithromycin, erythromycin, roxithromycin, tylosin, chloramphenicol, and nourseothricin sulfate by conjugation in vitro to E. faecalis JH2-2, Lactococcus lactis Bu2, and Listeria innocua L19. Its nucleotide sequence of 50237 base pairs represents the largest, fully sequenced conjugative multiresistance plasmid of enterococci (Plasmid 46 (2001) 170). The gene for chloramphenicol resistance (cat) was identified as an acetyltransferase identical to the one of plasmid pIP501 of Streptococcus agalactiae. Erythromycin resistance is due to a 23S ribosomal RNA methyl transferase, again as found in pIP501 (ermB). The aminoglycoside resistance genes are packed in tandem as in transposon Tn5405 of Staphylococcus aureus: an aminoglycoside 6-adenyltransferase, a streptothricin acetyl transferase, and an aminoglycoside phosphotransferase.). Identical resistance genes are known from pathogens like Streptococcus pyogenes, S. agalactiae, S. aureus, Campylobacter coli, Clostridium perfringens, and Clostridium difficile. pRE25 is composed of a 30.5-kbp segment almost identical to pIP501. Of the 15 genes involved in conjugative transfer, 10 codes for putative transmembrane proteins (e.g. trsB, traC, trsF, trsJ, and trsL). The enterococcal part is joined into the pIP501 part by insertion elements IS1216V of E. faecium Tn1545 (three copies), and homologs of IS1062 (E. faecalis) and IS1485 (E. faecium). pRE25 demonstrates that enterococci from fermented food do participate in the molecular communication between Gram-positive and Gram-negative bacteria of the human and animal microflora.200314597005
520660.9163Draft genome sequence of an extensively drug-resistant Pseudomonas aeruginosa isolate belonging to ST644 isolated from a footpad infection in a Magellanic penguin (Spheniscus magellanicus). OBJECTIVES: The incidence of multidrug-resistant bacteria in wildlife animals has been investigated to improve our knowledge of the spread of clinically relevant antimicrobial resistance genes. The aim of this study was to report the first draft genome sequence of an extensively drug-resistant (XDR) Pseudomonas aeruginosa ST644 isolate recovered from a Magellanic penguin with a footpad infection (bumblefoot) undergoing rehabilitation process. METHODS: The genome was sequenced on an Illumina NextSeq(®) platform using 150-bp paired-end reads. De novo genome assembly was performed using Velvet v.1.2.10, and the whole genome sequence was evaluated using bioinformatics approaches from the Center of Genomic Epidemiology, whereas an in-house method (mapping of raw whole genome sequence reads) was used to identify chromosomal point mutations. RESULTS: The genome size was calculated at 6436450bp, with 6357 protein-coding sequences and the presence of genes conferring resistance to aminoglycosides, β-lactams, phenicols, sulphonamides, tetracyclines, quinolones and fosfomycin; in addition, mutations in the genes gyrA (Thr83Ile), parC (Ser87Leu), phoQ (Arg61His) and pmrB (Tyr345His), conferring resistance to quinolones and polymyxins, respectively, were confirmed. CONCLUSION: This draft genome sequence can provide useful information for comparative genomic analysis regarding the dissemination of clinically significant antibiotic resistance genes and XDR bacterial species at the human-animal interface.201829277728
545270.9161Multidrug Resistance Plasmid pTZC1 Could Be Pooled among Cutibacterium Strains on the Skin Surface. Acne vulgaris is a chronic inflammatory skin disease that is exacerbated by Cutibacterium acnes. Although antimicrobials such as macrolides, clindamycin, and tetracyclines are used to treat acne caused by C. acnes, the increasing prevalence of antimicrobial-resistant C. acnes strains has become a global concern. In this study, we investigated the mechanism by which interspecies transfer of multidrug-resistant genes can lead to antimicrobial resistance. Specifically, the transfer of pTZC1 between C. acnes and C. granulosum isolated from specimens of patients with acne was investigated. Among the C. acnes and C. granulosum isolated from 10 patients with acne vulgaris, 60.0% and 70.0% of the isolates showed resistance to macrolides and clindamycin, respectively. The multidrug resistance plasmid pTZC1, which codes for macrolide-clindamycin resistance gene erm(50) and tetracycline resistance gene tet(W), was identified in both C. acnes and C. granulosum isolated from the same patient. In addition, whole-genome sequencing revealed that the pTZC1 sequences of C. acnes and C. granulosum showed 100% identity using comparative whole-genome sequencing analysis. Therefore, we hypothesize that the horizontal transfer of pTZC1 between C. acnes and C. granulosum strains may occur on the skin surface. The plasmid transfer test revealed a bidirectional transfer of pTZC1 between C. acnes and C. granulosum, and transconjugants that obtained pTZC1 exhibited multidrug resistance. In conclusion, our results revealed that the multidrug resistance plasmid pTZC1 could be transferred between C. acnes and C. granulosum. Furthermore, since pTZC1 transfer among different species may aid in the prevalence of multidrug resistant strains, antimicrobial resistance genes may have been pooled on the skin surface. IMPORTANCE The emergence of antimicrobial resistance not only in Cutibacterium acnes strain but also other skin bacteria such as Staphylococcus epidermidis is a big concern due to antimicrobial use for the treatment of acne vulgaris. Increased prevalence of macrolides-clindamycin resistant C. acnes relates to the acquisition of exogenous antimicrobial resistance genes. erm(50) is harbored by the multidrug resistance plasmid pTZC1, which has been found in C. acnes and C. granulosum strains isolated from patients with acne vulgaris. In this study, C. acnes and C. granulosum with pTZC1 were found in the same patient, and plasmid transfer between C. acnes and C. granulosum was proved by transconjugation assay. This study showed plasmid transfer between other species and the possibility of further prevalence antimicrobial resistance between Cutibacterium species.202336847559
200180.9160Identification of plasmids co-carrying cfr(D)/optrA and cfr(D2)/poxtA linezolid resistance genes in two Enterococcus avium isolates from swine brain. Oxazolidinones are critically important antibiotics to treat human infections caused by multidrug-resistant bacteria, therefore the occurrence of linezolid-resistant enterococci from food-producing animals poses a serious risk to human health. In this study, Enterococcus avium 38157 and 44917 strains, isolated from the brain of two unrelated piglets, were found to carry the linezolid resistance genes cfr(D)-optrA, and cfr(D2)-poxtA, respectively. Whole genome sequencing analysis of E. avium 38157 revealed that the genes were co-located on the 36.5-kb pEa_cfr(D)-optrA plasmid showing high identity with the pAT02-c of Enterococcus faecium AT02 from pet food. The optrA region, was 99% identical to the one of the pAv-optrA plasmid from a bovine Aerococcus viridans strain, whereas the cfr(D) genetic context was identical to that of the plasmid 2 of E. faecium 15-307.1. pEa_cfr(D)-optrA was not transferable to enterococcal recipients. In E. avium 44917 a cfr(D)-like gene, named cfr(D2), and the poxtA gene were co-located on the transferable 42.6-kb pEa-cfr(D2)-poxtA plasmid 97% identical to the Tn6349 transposon of the human MRSA AOUC-0915. The cfr(D2) genetic context, fully replaced the Tn6644 that in S. aureus AOUC-0915 harbor the cfr gene. In conclusion, this is, the best of our knowledge, the first report of the new cfr(D2) gene variant. The occurrence of plasmids co-carrying two linezolid resistance genes in enterococci from food-producing animals needs close surveillance to prevent their spread to human pathogens.202337116421
301390.9156Nucleotide sequence and organization of the multiresistance plasmid pSCFS1 from Staphylococcus sciuri. OBJECTIVES: The multiresistance plasmid pSCFS1 from Staphylococcus sciuri was sequenced completely and analysed with regard to its gene organization and the putative role of a novel ABC transporter in antimicrobial resistance. METHODS: Plasmid pSCFS1 was transformed into Staphylococcus aureus RN4220, overlapping restriction fragments were cloned into Escherichia coli plasmid vectors and sequenced. For further analysis of the ABC transporter, a approximately 3 kb EcoRV-HpaI fragment was cloned into the staphylococcal plasmid pT181MCS and the respective S. aureus RN4220 transformants were subjected to MIC determination. RESULTS: A total of 14 ORFs coding for proteins of >100 amino acids were detected within the 17 108 bp sequence of pSCFS1. Five of them showed similarity to recombination/mobilization genes while another two were similar to plasmid replication genes. In addition to the previously described genes cfr for chloramphenicol/florfenicol resistance and erm(33) for inducible resistance to macrolide-lincosamide-streptogramin B resistance, a Tn554-like spectinomycin resistance gene and Tn554-related transposase genes were identified. Moreover, a novel ABC transporter was detected and shown to mediate low-level lincosamide resistance. CONCLUSION: Plasmid pSCFS1 is composed of various parts which show similarity to sequences known to occur on plasmids or transposons of Gram-positive, but also Gram-negative bacteria. It is likely that pSCFS1 represents the result of inter-plasmid recombination events also involving the truncation of a Tn554-like transposon.200415471995
2170100.9154Drug resistance in bacteria isolated from patients presenting with wounds at a non-profit Surgical Center in Phnom Penh, Cambodia from 2011-2013. BACKGROUND: Emerging antibiotic resistance amongst clinically significant bacteria is a public health issue of increasing significance worldwide, but it is relatively uncharacterized in Cambodia. In this study we performed standard bacterial cultures on samples from wounds at a Non-Governmental-Organization (NGO) Hospital in Phnom Penh, Cambodia. Testing was performed to elucidate pathogenic bacteria causing wound infections and the antibiotic resistance profiles of bacterial isolates. All testing was performed at the Naval Medical Research Unit, No.2 (NAMRU-2) main laboratory in Phnom Penh, Cambodia. METHODS: Between 2011-2013, a total of 251 specimens were collected from patients at the NGO hospital and analyzed for bacterial infection by standard bacterial cultures techniques. Specimens were all from wounds and anonymous. No specific clinical information accompanied the submitted specimens. Antibiotic susceptibility testing, and phenotypic testing for extended-spectrum beta-lactamase (ESBL) were performed and reported based on CLSI guidelines. Further genetic testing for CTX-M, TEM and SHV ESBLs was accomplished using PCR. RESULTS: One-hundred and seventy-six specimens were positive following bacterial culture (70 %). Staphlycoccus aureus was the most frequently isolated bacteria. Antibiotic drug resistance testing revealed that 52.5 % of Staphlycoccus aureus isolates were oxacillin resistant. For Escherichia coli isolates, 63.9 % were ciprofloxacin and levofloxacin resistant and 96 % were ESBL producers. Resistance to meropenem and imipenem was observed in one of three Acinetobacter spp isolates. CONCLUSIONS: This study is the first of its kind detailing the antibiotic resistance profiles of pathogenic bacteria causing wound infections at a single surgical hospital in Cambodia. The reported findings of this study demonstrate significant antibiotic resistance in bacteria from injured patients and should serve to guide treatment modalities in Cambodia.201528883936
1423110.9151Distribution and molecular characterization of carbapenemase-producing gram-negative bacteria in Henan, China. This study aimed to investigate the epidemiological characteristics and trends over time of carbapenemase-producing (e.g., KPC, NDM, VIM, IMP, and OXA-48) Gram-negative bacteria (CPGNB). Non-duplicated multi-drug resistant Gram-negative bacteria (MDRGNB) were collected from the First Affiliated Hospital of Zhengzhou University from April 2019 to February 2023. Species identification of each isolate was performed using the Vitek2 system and confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry according to the manufacturer's instructions. PCR detected carbapenem resistance genes in the strains, strains carrying carbapenem resistance genes were categorized as CPGNB strains after validation by carbapenem inactivation assay. A total of 5705 non-repetitive MDRGNB isolates belonging to 78 different species were collected during the study period, of which 1918 CPGNB were validated, with the respiratory tract being the primary source of specimens. Epidemiologic statistics showed a significant predominance of ICU-sourced strains compared to other departments. Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa were the significant CPGNB in Henan, and KPC and NDM were the predominant carbapenemases. Carbapenem-resistant infections in Henan Province showed an overall increasing trend, and the carriage of carbapenemase genes by CPGNB has become increasingly prevalent and complicated. The growing prevalence of CPGNB in the post-pandemic era poses a significant challenge to public safety.202438909136
3014120.9150Complete sequence of the multi-resistance plasmid pV7037 from a porcine methicillin-resistant Staphylococcus aureus. The aim of this study was to determine the complete sequence of the multi-resistance plasmid pV7037 to gain insight into the structure and organization of this plasmid. Of the four XbaI clones of pV7037, one clone of 17,577 bp has already been sequenced and shown to carry a multi-resistance gene cluster. The remaining three clones of approximately 12.5, 6.5 and 4.5 kb were sequenced, the entire plasmid sequence correctly assembled and investigated for reading frames. In addition, two reading frames one coding for an ABC transporter and the other coding for an rRNA methylase were cloned and expressed in a S. aureus host to see whether they confer antimicrobial resistance properties. Plasmid pV7037 proved to be 40,971 bp in size. Besides the previously determined resistance gene cluster, it carried a functionally active tet(L) gene for tetracycline resistance, a complete cadDX operon for cadmium resistance and also a variant of the β-lactamase transposon Tn552. Two single bp deletions, which resulted in frame shifts, functionally deleted the genes for the BlaZ β-lactamase and the signal transducer protein BlaR1 in this Tn552 variant of pV7037. Plasmid pV7037 seems to be composed of various parts previously known from plasmids and transposons of staphylococci and other Gram-positive bacteria. However, there are also parts of the plasmid which do not show any homology to so far known sequences deposited in the databases. The novel ABC transporter and rRNA methylase genes identified on pV7037 do not seem to play a role in antimicrobial resistance. The co-location of numerous antimicrobial resistance genes bears the risk of co-transfer and co-selection of resistance genes, but also persistence of resistance genes even if no direct selective pressure by the use of the respective antimicrobial agents is applied.201323953027
2189130.9149High prevalence of Panton-Valentine Leucocidin (PVL) toxin carrying MRSA and multidrug resistant gram negative bacteria in late onset neonatal sepsis indicate nosocomial spread in a Pakistani tertiary care hospital. BACKGROUND: Neonatal sepsis has high incidence with significant mortality and morbidity rates in Pakistan. We investigated common etiological patterns of neonatal sepsis at a tertiary care setup. METHODS: 90 pus and blood, gram negative and gram positive bacterial isolates were analyzed for virulence and antibiotic resistance gene profiling using PCR and disc diffusion methods. RESULTS: Staphylococcus aureus showed strong association with neonatal sepsis (43 %) followed by Citrobacter freundii (21 %), Pseudomonas aeruginosa (13 %), Escherichia coli (15 %) and Salmonella enterica (8 %). Molecular typing of E. coli isolates depicted high prevalence of the virulent F and B2 phylogroups, with 4 hypervirulent phylogroup G isolates. 76.9 % S. aureus isolates showed presence of Luk-PV, encoding for Panton-valentine leucocidin (PVL) toxin with majority also carrying MecA gene and classified as methicillin resistant S. aureus (MRSA). ecpA, papC, fimH and traT virulence genes were detected in E. coli and Salmonella isolates. 47 % Citrobacter freundii isolates carried the shiga like toxin SltII B. Antimicrobial resistance profiling depicted common resistance to cephalosporins, beta lactams and fluoroquinolones. CONCLUSION: Presence of PVL carrying MRSA and multidrug resistant gram negative bacteria, all isolated from late onset sepsis neonates indicate a predominant nosocomial transmission pattern which may complicate management of the disease in NICU setups.202336621204
5420140.9147A high incidence and coexistence of multiresistance genes cfr and optrA among linezolid-resistant enterococci isolated from a teaching hospital in Wenzhou, China. Linezolid is considered as a last-resort antimicrobial agent, the resistance of which is of great concern. The aim of this study was to investigate the mechanisms and transferability of linezolid resistance and molecular epidemiology of linezolid-resistant enterococcal isolates in Wenzhou, China. A collection of 1623 enterococcal strains, including 789 Enterococcus faecalis and 834 Enterococcus faecium, were isolated from our hospital during 2011-2016. Antimicrobial susceptibility testing and clinical data analysis were performed. Molecular mechanisms of linezolid resistance, including the existence of resistance genes cfr and optrA, as well as the mutations in 23S rRNA and ribosomal proteins L3, L4, and L22, were investigated by PCR and sequencing. Conjugation experiments were conducted, and epidemiological characteristics were analyzed by PFGE and MLST. In our study, 31 (3.93%) E. faecalis and 2 (0.24%) E. faecium exhibited resistance to linezolid. Risk factors correlated with linezolid-resistant enterococcal infections included gastrointestinal surgery hospitalization, urogenital disorders, tumor, diabetes, and polymicrobial infections. Among these isolates, 6 (18.18%) harbored cfr, 9 (27.27%) harbored optrA, and 18 (54.55%) co-harbored cfr and optrA. However, mutational mechanisms were not found in this study. Conjugation experiments demonstrated the transferability of cfr and optrA between Gram-positive and Gram-negative bacteria. The clone of these isolates was diverse and scattered. It is noteworthy that cfr and optrA were the main mechanisms of linezolid resistance in this study, posing a potential risk of spread of linezolid resistance. Strikingly, it reported firstly that the two transferable resistance genes cfr and optrA coexisted in the same E. faecalis isolates.201829909468
6183150.9147Characterization of putative multidrug resistance transporters of the major facilitator-superfamily expressed in Salmonella Typhi. Multidrug resistance mediated by efflux pumps is a well-known phenomenon in infectious bacteria. Although much work has been carried out to characterize multidrug efflux pumps in Gram-negative and Gram-positive bacteria, such information is still lacking for many deadly pathogens. The aim of this study was to gain insight into the substrate specificity of previously uncharacterized transporters of Salmonella Typhi to identify their role in the development of multidrug resistance. S. Typhi genes encoding putative members of the major facilitator superfamily were cloned and expressed in the drug-hypersensitive Escherichia coli strain KAM42, and tested for transport of 25 antibacterial compounds, including representative antibiotics of various classes, antiseptics, dyes and detergents. Of the 15 tested putative transporters, STY0901, STY2458 and STY4874 exhibited a drug-resistance phenotype. Among these, STY4874 conferred resistance to at least ten of the tested antimicrobials: ciprofloxacin, norfloxacin, levofloxacin, kanamycin, streptomycin, gentamycin, nalidixic acid, chloramphenicol, ethidium bromide, and acriflavine, including fluoroquinolone antibiotics, which were drugs of choice to treat S. Typhi infections. Cell-based functional studies using ethidium bromide and acriflavine showed that STY4874 functions as a H(+)-dependent exporter. These results suggest that STY4874 may be an important drug target, which can now be tested by studying the susceptibility of a STY4874-deficient S. Typhi strain to antimicrobials.201525724589
3753160.9146Flavophospholipol use in animals: positive implications for antimicrobial resistance based on its microbiologic properties. Bambermycin (flavophospholipol) is a phosphoglycolipid antimicrobial produced by various strains of Streptomyces. It is active primarily against Gram-positive bacteria because of inhibition of transglycosylase and thus of cell wall synthesis. Bambermycin is used as a feed additive growth promoter in cattle, pigs, chickens, and turkeys, but has no therapeutic use in humans or animals. Flavophospholipol is known to suppress certain microorganisms (e.g., Staphylococcus spp. and Enterococcus faecalis) and thus contributes to an improved equilibrium of the gut microflora providing a barrier to colonization with pathogenic bacteria and resultant improved weight gain and feed conversion. Flavophospholipol has also been shown to decrease the frequency of transferable drug resistance among Gram-negative enteropathogens and to reduce the shedding of pathogenic bacteria such as Salmonella in pigs, calves, and chickens. Plasmid-mediated resistance to bambermycin has not been described. Likewise, cross-resistance among bacteria between bambermycin and penicillin, tetracycline, streptomycin, erythromycin, or oleandromycin has not been observed. This brief review summarizes the antimicrobial properties of bambermycin, in particular, its potentially favorable role in decreasing antimicrobial resistance.200616698216
3754170.9145Cancer departments as a source of resistant bacteria and fungi? Antimicrobial resistance increases worldwide. Among many factors, such as clonal spread of genes of resistance among and intra species, local epidemiology, nosocomial transmission, also consumption of antimicrobials may be responsible. Cancer departments, mainly in centers treating hematologic malignancies and organizing bone marrow transplantation (BMT) are known to have extensive consumption of either prophylactically or therapeutically administered antibiotics and antifungals. It is worthy to remember, that first strains of quinolone resistant E. coli, vancomycin resistant enterococci and staphylococci and fluconazol-resistant Candida albicans appeared in the patients treated for cancer with antineoplastic chemotherapy, resulting in profound granulocytopenia. Therefore, assessment of risks of antibiotic prophylaxis with quinolones and azoles and extensive use of empiric therapy with glycopeptides and polyenes needs to be considered. Intensive prophylactic strategies should be limited to group of high risk, leukemic patients or BMT recipients.199910355526
5476180.9145Bile Carriage of optrA-Positive Enterococcus faecium in a Patient with Choledocholith. We isolated one Enterococcus faecium isolate SZ21B15 from a bile sample of a patient with choledocholith in Shenzhen, China in 2021. It was positive for oxazolidinone resistance gene optrA and was intermediate to linezolid. The whole genome of E. faecium SZ21B15 was sequenced by Illumina Hiseq. It belonged to ST533 within the clonal complex 17. The optrA gene and additional two resistance genes fexA and erm(A) were located within a 25,777-bp multiresistance region, which was inserted into the chromosomal radC gene, being chromosomal intrinsic resistance genes. The chromosomal optrA gene cluster found in E. faecium SZ21B15 was closely related to the corresponding regions of multiple optrA-carrying plasmids or chromosomes from Enterococcus, Listeria, Staphylococcus, and Lactococcus strains. It further highlights the ability of the optrA cluster that transfers between plasmids and chromosomes and evolves by a series of molecular recombination events. IMPORTANCE Oxazolidinone are effective antimicrobial agents for the treatment of infections caused by multidrug-resistant Gram-positive bacteria, including vancomycin-resistant enterococci. The emergence and global spread of transferable oxazolidinone resistance genes such as optrA is worrisome. Enterococcus spp. can become causes of hospital-associated infections and are also widely distributed in the gastrointestinal tracts of animals and the natural environment. In this study, one E. faecium isolate from bile sample carried chromosomal optrA, being intrinsic resistance gene. optrA-positive E. faecium in bile not only makes the treatment of gallstones difficult, but also may become a reservoir of resistance genes in the body.202336976027
5454190.9144Identification of an Enterococcus faecium strain isolated from raw bovine milk co-harbouring the oxazolidinone resistance genes optrA and poxtA in China. Oxazolidinones are potent antimicrobial agents used to treat human infections caused by multidrug-resistant Gram-positive bacteria. The growing resistance to oxazolidinones poses a significant threat to public health. In August 2021, a linezolid-resistant Enterococcus faecium BN83 was isolated from a raw milk sample of cow in Inner Mongolia, China. This isolate exhibited a multidrug resistance phenotype and was resistant to most of drugs tested including linezolid and tedizolid. PCR detection showed that two mobile oxazolidinones resistance genes, optrA and poxtA, were present in this isolate. Whole genome sequencing analysis revealed that the genes optrA and poxtA were located on two different plasmids, designated as pBN83-1 and pBN83-2, belonging to RepA_N and Inc18 families respectively. Genetic context analysis suggested that optrA gene on plasmid pBN83-1 was located in transposon Tn6261 initially found in E. faecalis. Comprehensive analysis revealed that Tn6261 act as an important horizontal transmission vector for the spread of optrA in E. faecium. Additionally, poxtA-bearing pBN83-2 displayed high similarity to numerous plasmids from Enterococcus of different origin and pBN83-2-like plasmid represented a key mobile genetic element involved in movement of poxtA in enterococcal species. The presence of optrA- and poxtA-carrying E. faecium in raw bovine milk represents a public health concern and active surveillance is urgently warranted to investigate the prevalence of oxazolidinone resistance genes in animal-derived food products.202438718528