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Given the lack of genetic characterization data for multidrug-resistant (MDR) Salmonella in South Korean poultry, we analyzed 53 MDR Salmonella strains from 1232 poultry meat samples (723 chicken, 509 duck) using whole-genome sequencing. Five serotypes were identified: S. Infantis (30/53, 56.6%), S. Enteritidis (11/53, 20.8%), S. Virchow (9/53, 17.0%), S. Agona (2/53, 3.8%), and S. Indiana (1/53, 1.9%). Sequence types (STs) included ST32, ST11, ST16, ST13, and ST17, with three major clusters, each having two subclusters. Eight core genome sequence types (cgSTs) were identified: 225993, 2268, 58360, 150996, 232041, 96964, 117577, and 267045. Salmonella Infantis and S. Enteritidis had two (117577, 267045) and three (225993, 2268, 58360) cgSTs, respectively, whereas S. Virchow showed allelic differences in identical cgSTs. The S. Enteritidis subcluster was classified as chicken or duck. Twenty-eight antimicrobial resistance genes (ARGs), 10 plasmid replicons, 11 Salmonella pathogenicity islands (SPIs), and 230 virulence genes were identified, showing distinct profiles by cluster and subcluster. Salmonella Infantis, the primary MDR Salmonella, carried the IncFIB (pN55391) plasmid, 10–11 ARGs, nine SPIs, and approximately 163 virulence genes. Three major MDR Salmonella serotypes (S. Infantis, S. Enteritidis, and S. Virchow) had specific genetic profiles that can inform epidemiological surveillance. [ABSTRACT FROM AUTHOR]

Given the lack of genetic characterization data for multidrug-resistant (MDR) Salmonella in South Korean poultry, we analyzed 53 MDR Salmonella strains from 1232 poultry meat samples (723 chicken, 509 duck) using whole-genome sequencing. Five serotypes were identified: S. Infantis (30/53, 56.6%), S. Enteritidis (11/53, 20.8%), S. Virchow (9/53, 17.0%), S. Agona (2/53, 3.8%), and S. Indiana (1/53, 1.9%). Sequence types (STs) included ST32, ST11, ST16, ST13, and ST17, with three major clusters, each having two subclusters. Eight core genome sequence types (cgSTs) were identified: 225993, 2268, 58360, 150996, 232041, 96964, 117577, and 267045. Salmonella Infantis and S. Enteritidis had two (117577, 267045) and three (225993, 2268, 58360) cgSTs, respectively, whereas S. Virchow showed allelic differences in identical cgSTs. The S. Enteritidis subcluster was classified as chicken or duck. Twenty-eight antimicrobial resistance genes (ARGs), 10 plasmid replicons, 11 Salmonella pathogenicity islands (SPIs), and 230 virulence genes were identified, showing distinct profiles by cluster and subcluster. Salmonella Infantis, the primary MDR Salmonella, carried the IncFIB (pN55391) plasmid, 10–11 ARGs, nine SPIs, and approximately 163 virulence genes. Three major MDR Salmonella serotypes (S. Infantis, S. Enteritidis, and S. Virchow) had specific genetic profiles that can inform epidemiological surveillance.

The Enterobacterales order is a massive group of Gram-negative bacteria comprised of pathogenic and nonpathogenic members, including beneficial commensal gut microbiota. The pathogenic members produce several pathogenic or virulence factors that enhance their pathogenic properties and increase the severity of the infection. The members of Enterobacterales can also develop resistance against the common antimicrobial agents, a phenomenon called antimicrobial resistance (AMR). Many pathogenic Enterobacterales members are known to possess antimicrobial resistance. This review discusses the virulence factors, pathogenicity, and infections caused by multidrug-resistant Enterobacterales, especially E. coli and some other bacterial species sharing similarities with the Enterobacterales members. We also discuss both conventional and modern approaches used to combat the infections caused by them. Understanding the virulence factors produced by the pathogenic bacteria will help develop novel strategies and methods to treat infections caused by them. [ABSTRACT FROM AUTHOR]

Delafloxacin is a novel fluoroquinolone agent that is approved for clinical application. In this study, we analyzed the antibacterial efficacy of delafloxacin in a collection of 47 Escherichia coli strains. Antimicrobial susceptibility testing was performed by the broth microdilution method and minimum inhibitory concentration (MIC) values were determined for delafloxacin, ciprofloxacin, levofloxacin, moxifloxacin, ceftazidime, cefotaxime, and imipenem. Two multidrug-resistant E. coli strains, which exhibited delafloxacin and ciprofloxacin resistance as well as extended-spectrum beta-lactamase (ESBL) phenotype, were selected for whole-genome sequencing (WGS). In our study, delafloxacin and ciprofloxacin resistance rates were 47% (22/47) and 51% (24/47), respectively. In the strain collection, 46 E. coli were associated with ESBL production. The MIC50 value for delafloxacin was 0.125 mg/L, while all other fluoroquinolones had an MIC50 value of 0.25 mg/L in our collection. Delafloxacin susceptibility was detected in 20 ESBL positive and ciprofloxacin resistant E. coli strains; by contrast, E. coli strains that exhibited a ciprofloxacin MIC value above 1 mg/L were delafloxacin-resistant. WGS analysis on the two selected E. coli strains (920/1 and 951/2) demonstrated that delafloxacin resistance is mediated by multiple chromosomal mutations, namely, five mutations in E. coli 920/1 (gyrA S83L, D87N, parC S80I, E84V, and parE I529L) and four mutations in E. coli 951/2 (gyrA S83L, D87N, parC S80I, and E84V). Both strains carried an ESBL gene, blaCTX-M-1 in E. coli 920/1 and blaCTX-M-15 in E. coli 951/2. Based on multilocus sequence typing, both strains belong to the E. coli sequence type 43 (ST43). In this paper, we report a remarkable high rate (47%) of delafloxacin resistance among multidrug-resistant E. coli as well as the E. coli ST43 international high-risk clone in Hungary. [ABSTRACT FROM AUTHOR]

Periodontal disease is caused by different gram-negative anaerobic bacteria; however, Escherichia coli has also been isolated from periodontitis and its role in periodontitis is less known. This study aimed to determine the variability in virulence genotype, antibiotic resistance phenotype, biofilm formation, phylogroups, and serotypes in different emerging periodontal strains of Escherichia coli, isolated from patients with periodontal disease and healthy controls. E. coli, virulence genes, and phylogroups, were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, biofilm formation was quantified using polystyrene microtiter plates, and serotypes were determined by serotyping. Although E. coli was not detected in the controls (n = 70), it was isolated in 14.7% (100/678) of the patients. Most of the strains (n = 81/100) were multidrug-resistance. The most frequent adhesion genes among the strains were fimH and iha, toxin genes were usp and hlyA, iron-acquisition genes were fyuA and irp2, and protectin genes were ompT, and KpsMT. Phylogroup B2 and serotype O25:H4 were the most predominant among the strains. These findings suggest that E. coli may be involved in periodontal disease due to its high virulence, multidrug-resistance, and a wide distribution of phylogroups and serotypes. [ABSTRACT FROM AUTHOR]

Disinfectants and biosecurity are critically important to control microbial diseases. Resistance to disinfectants compromises sectors such as agriculture and healthcare systems. Currently, efflux pumps are the most common mechanism of antimicrobial resistance. This study aimed to identify the efflux transporters responsible for disinfectant resistance in a multidrug-resistant isolate Serratia sp. HRI compared to a susceptible Serratia sp. type strain. An efflux system profile was generated using the Transporter Automatic Annotation Pipeline (TransAAP) for both isolates. Thereafter, the efflux pump inhibitors, reserpine (RSP) and carbonyl cyanide 3-chlorophenylhydrazone (CCCP) were used to reveal the role of efflux pumps in susceptibility to three disinfectants (Didecyldimethylammonium chloride, HyperCide®, and benzalkonium chloride). Interestingly, the resistant isolate had fewer efflux systems in total compared to the type strain and fewer efflux systems classified as resistance efflux pumps. After the addition of RSP, a significant reduction in resistance capabilities against all three antimicrobials was observed for both isolates. However, CCCP supplementation produced mixed results with some outcomes suggesting the involvement of the Eagle effect. This study provides evidence that efflux pumps are responsible for the disinfectant resistance phenotype of the Serratia species due to the increased susceptibility when efflux pump inhibitors are added. [ABSTRACT FROM AUTHOR]

Multidrug-resistant (MDR) Pseudomonas aeruginosa poses a great challenge to clinical treatment. In this study, we characterized a ST768 MDR P. aeruginosa strain, Pa150, that was isolated from a diabetic foot patient. The minimum inhibitory concentration (MIC) assay showed that Pa150 was resistant to almost all kinds of antibiotics, especially aminoglycosides. Whole genome sequencing revealed multiple antibiotic resistant genes on the chromosome and a 437-Kb plasmid (named pTJPa150) that harbors conjugation-related genes. A conjugation assay verified its self-transmissibility. On the pTJPa150 plasmid, we identified a 16S rRNA methylase gene, rmtB, that is flanked by mobile genetic elements (MGEs). The transfer of the pTJPa150 plasmid or the cloning of the rmtB gene into the reference strain, PAO1, significantly increased the bacterial resistance to aminoglycoside antibiotics. To the best of our knowledge, this is the first report of an rmtB-carrying conjugative plasmid isolated from P. aeruginosa, revealing a novel possible transmission mechanism of the rmtB gene. [ABSTRACT FROM AUTHOR]

The spread of carbapenemase-producing (CP) Enterobacterales is currently a worldwide concern, especially in the elderly. Twelve CP-E. coli isolated from rectal swabs of colonized inpatients aged ≥65 years from four hospitals in two Italian cities (Milan and Rome) were analyzed by whole genome sequencing (WGS) to obtain multi-locus sequence typing (MLST), identification of carbapenemase-encoding genes, resistome, plasmid content, and virulence genes. MLST analysis showed the presence of 10 unrelated lineages: ST410 (three isolates from three different hospitals in two cities) and ST12, ST38, ST69, ST95, ST131, ST189, ST648, ST1288, and ST1598 (one isolate each). Most isolates (9/12, 75%) contained a serine-β-lactamase gene (5 blaKPC-3, 2 blaKPC-2, and 2 blaOXA-181), while three isolates harbored a metallo-β-lactamase gene (two blaNDM-5 and one blaVIM-1). In most CP-E. coli, the presence of more than one plasmid was observed, with the predominance of IncF. Several virulence genes were detected. All isolates contained genes enhancing the bacterial fitness, such as gad and terC, and all isolates but one, fimH, encoding type 1 fimbriae. In conclusion, CP-E. coli clones colonizing elderly patients showed heterogeneous genetic backgrounds. We recommend strict surveillance to monitor and prevent the spread of successful, high-risk clones in healthcare settings. [ABSTRACT FROM AUTHOR]

The Enterobacterales order is a massive group of Gram-negative bacteria comprised of pathogenic and nonpathogenic members, including beneficial commensal gut microbiota. The pathogenic members produce several pathogenic or virulence factors that enhance their pathogenic properties and increase the severity of the infection. The members of Enterobacterales can also develop resistance against the common antimicrobial agents, a phenomenon called antimicrobial resistance (AMR). Many pathogenic Enterobacterales members are known to possess antimicrobial resistance. This review discusses the virulence factors, pathogenicity, and infections caused by multidrug-resistant Enterobacterales, especially E. coli and some other bacterial species sharing similarities with the Enterobacterales members. We also discuss both conventional and modern approaches used to combat the infections caused by them. Understanding the virulence factors produced by the pathogenic bacteria will help develop novel strategies and methods to treat infections caused by them.

Delafloxacin is a novel fluoroquinolone agent that is approved for clinical application. In this study, we analyzed the antibacterial efficacy of delafloxacin in a collection of 47 Escherichia coli strains. Antimicrobial susceptibility testing was performed by the broth microdilution method and minimum inhibitory concentration (MIC) values were determined for delafloxacin, ciprofloxacin, levofloxacin, moxifloxacin, ceftazidime, cefotaxime, and imipenem. Two multidrug-resistant E. coli strains, which exhibited delafloxacin and ciprofloxacin resistance as well as extended-spectrum beta-lactamase (ESBL) phenotype, were selected for whole-genome sequencing (WGS). In our study, delafloxacin and ciprofloxacin resistance rates were 47% (22/47) and 51% (24/47), respectively. In the strain collection, 46 E. coli were associated with ESBL production. The MIC50 value for delafloxacin was 0.125 mg/L, while all other fluoroquinolones had an MIC50 value of 0.25 mg/L in our collection. Delafloxacin susceptibility was detected in 20 ESBL positive and ciprofloxacin resistant E. coli strains; by contrast, E. coli strains that exhibited a ciprofloxacin MIC value above 1 mg/L were delafloxacin-resistant. WGS analysis on the two selected E. coli strains (920/1 and 951/2) demonstrated that delafloxacin resistance is mediated by multiple chromosomal mutations, namely, five mutations in E. coli 920/1 (gyrA S83L, D87N, parC S80I, E84V, and parE I529L) and four mutations in E. coli 951/2 (gyrA S83L, D87N, parC S80I, and E84V). Both strains carried an ESBL gene, blaCTX-M-1 in E. coli 920/1 and blaCTX-M-15 in E. coli 951/2. Based on multilocus sequence typing, both strains belong to the E. coli sequence type 43 (ST43). In this paper, we report a remarkable high rate (47%) of delafloxacin resistance among multidrug-resistant E. coli as well as the E. coli ST43 international high-risk clone in Hungary.

Wild and feral birds are known to be involved in the maintenance and dissemination of clinically-important antimicrobial-resistant pathogens, such as extended-spectrum β-lactamase (ESBL) and carbapenemase-producing Enterobacteriaceae. The aim of our study was to evaluate the presence of ESBL- and carbapenemase-producing Escherichia coli among wild and feral birds from Greece and to describe their antimicrobial resistance characteristics. In this context, fecal samples of 362 birds were collected and cultured. Subsequently, the antimicrobial resistance pheno- and geno-type of all the obtained E. coli isolates were determined. A total of 12 multidrug-resistant (MDR), ESBL-producing E. coli were recovered from eight different wild bird species. Eleven of these isolates carried a blaCTX-M-1 group gene alone or in combination with blaTEM and one carried only blaTEM. AmpC, fluoroquinolone, trimethoprim/sulfamethoxazole, aminoglycoside and macrolide resistance genes were also detected. Additionally, one carbapenemase-producing E. coli was identified, harboring blaNDM along with a combination of additional resistance genes. This report describes the occurrence of ESBL- and carbapenemase-producing E. coli among wild avian species in Greece, emphasizing the importance of incorporating wild birds in the assessment of AMR circulation in non-clinical settings. [ABSTRACT FROM AUTHOR]

The emergence of multidrug-resistant (MDR) bacterial strains is one of the significant global challenges with regard to bacterial drug-resistance control. Enterobacter hormaechei organisms belong to the Enterobacter cloacae complex (ECC) and are commonly recognized as causative agents for hospital infections. Recently, a few E. hormaechei MDR strains associated with infection in piglets, calves, and a fox were reported, highlighting the important role of animals and livestock in the emergence and spread of antimicrobial resistance. In this study, the vaginal swab sample from a 5-year-old cow with multiple anamnestic infectious abortions was carefully investigated. The animal was unresponsive to antibiotic therapy recommended by the veterinarian. The MDR bacterial strain isolated from the bovine sample, designated as the Saratov_2019, belonged to Enterobacter hormaechei. The genome-based phylogenetic analysis identified the isolate to be Enterobacter hormaechei subsp. xiangfangensis. The genome of the Saratov_2019 contained a 6364 bp plasmid. Importantly, we revealed the novel sequence type ST1416 and 13 MDR genes correlating with the MDR phenotype in only the chromosome but not the plasmid. These findings indicate that the potential spread of this strain may pose a threat for both animal and human health. The data obtained here support the notion of the important role of livestock in the emergence and spread of antimicrobial resistance, promoting careful investigation of the MDR spectra for livestock-related bacterial isolates. To the best of our knowledge, this is the first report on the association of E. hormaechei subsp. xiangfangensis with the infection of the reproductive system in cattle. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is an opportunistic bacterium known to cause severe infections in humans and animals. It is one of the major bacteria causing subclinical and clinical mastitis, leading to significant economic losses in livestock industry. In this study, we have isolated and characterized 80 S. aureus clinical isolates from mastitis-infected animals. The analysis of antimicrobial susceptibility, molecular typing, biofilm production and genetic determinants was performed to understand molecular and phenotypic features of the prevalent pathogen. Our antibiotic susceptibility assays showed the majority (57.5%) of isolates to be multidrug-resistant (MDR), 38.75% resistant and 3.75% sensitive. We found 25% isolates to be methicillin-resistant S. aureus (MRSA) based on oxacillin susceptibility assays. In the MRSA group, maximum isolates (95%) were MDR compared to 45% in MSSA. Multilocus sequence typing (MLST) revealed 15 different STs; ST-97 was the most common ST, followed by ST-2459, ST-1, ST-9 and ST-72. The agr typing showed agr-I as the most common type, followed by type II and III. Most isolates developed biofilms, which ranged in intensity from strong to weak. The presence or absence of lukS, a virulence-related gene, was found to have a substantial relationship with the biofilm phenotype. However, no significant association was found between biofilm formation and antimicrobial resistance or other virulence genes. We also found four MRSA isolates that were mecA negative based on molecular assays. Our findings reveal the prevalence of multidrug-resistant S. aureus clinical isolates in India that are biofilm positive and have critical genetic factors for disease pathogenesis causing bovine mastitis. This study emphasizes the need for the comprehensive surveillance of S. aureus and other mastitis-causing pathogens to control the disease effectively. [ABSTRACT FROM AUTHOR]

Aquatic environments are recognized as one of the main reservoirs for the emergence and dissemination of high-risk lineages of multidrug-resistant (MDR) bacteria of public health concern. However, the genomic characteristics of antibiotic-resistant Escherichia coli isolates from aquatic origins remain limited. Herein, we examined the antibiotic resistance and virulence genomic profiles of three E. coli recovered from surface water in northwest Mexico. Antimicrobial susceptibility testing, whole-genome sequencing (WGS), and in-depth in silico analysis were performed. Two E. coli exhibited MDR phenotypes. WGS-based typing revealed genetic diversity, and phylogenetic analysis corroborated a notable divergent relationship among the studied E. coli. One E. coli strain, harboring enterotoxigenic and extraintestinal pathogenic-associated virulence genes, was assigned to the ST4 lineage. MDR E. coli, belonging to the international high-risk clones ST410 and ST617, carried genes and mutations conferring resistance to aminoglycosides, β-lactams, quinolones, sulfonamides, tetracyclines, and trimethoprim. This study describes, for the first time, the detection and genomic profiling of high-risk lineages of E. coli ST410 and ST617 from surface water in Mexico. Additionally, our results underscore the role of surface water as a reservoir for critical pathogenic and MDR E. coli clones and the need for the surveillance and monitoring of aquatic environments via WGS from the One Health perspective. [ABSTRACT FROM AUTHOR]

Periodontal disease is caused by different gram-negative anaerobic bacteria; however, Escherichia coli has also been isolated from periodontitis and its role in periodontitis is less known. This study aimed to determine the variability in virulence genotype, antibiotic resistance phenotype, biofilm formation, phylogroups, and serotypes in different emerging periodontal strains of Escherichia coli, isolated from patients with periodontal disease and healthy controls. E. coli, virulence genes, and phylogroups, were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, biofilm formation was quantified using polystyrene microtiter plates, and serotypes were determined by serotyping. Although E. coli was not detected in the controls (n = 70), it was isolated in 14.7% (100/678) of the patients. Most of the strains (n = 81/100) were multidrug-resistance. The most frequent adhesion genes among the strains were fimH and iha, toxin genes were usp and hlyA, iron-acquisition genes were fyuA and irp2, and protectin genes were ompT, and KpsMT. Phylogroup B2 and serotype O25:H4 were the most predominant among the strains. These findings suggest that E. coli may be involved in periodontal disease due to its high virulence, multidrug-resistance, and a wide distribution of phylogroups and serotypes.

Disinfectants and biosecurity are critically important to control microbial diseases. Resistance to disinfectants compromises sectors such as agriculture and healthcare systems. Currently, efflux pumps are the most common mechanism of antimicrobial resistance. This study aimed to identify the efflux transporters responsible for disinfectant resistance in a multidrug-resistant isolate Serratia sp. HRI compared to a susceptible Serratia sp. type strain. An efflux system profile was generated using the Transporter Automatic Annotation Pipeline (TransAAP) for both isolates. Thereafter, the efflux pump inhibitors, reserpine (RSP) and carbonyl cyanide 3-chlorophenylhydrazone (CCCP) were used to reveal the role of efflux pumps in susceptibility to three disinfectants (Didecyldimethylammonium chloride, HyperCide®, and benzalkonium chloride). Interestingly, the resistant isolate had fewer efflux systems in total compared to the type strain and fewer efflux systems classified as resistance efflux pumps. After the addition of RSP, a significant reduction in resistance capabilities against all three antimicrobials was observed for both isolates. However, CCCP supplementation produced mixed results with some outcomes suggesting the involvement of the Eagle effect. This study provides evidence that efflux pumps are responsible for the disinfectant resistance phenotype of the Serratia species due to the increased susceptibility when efflux pump inhibitors are added.

Multidrug-resistant (MDR) Pseudomonas aeruginosa poses a great challenge to clinical treatment. In this study, we characterized a ST768 MDR P. aeruginosa strain, Pa150, that was isolated from a diabetic foot patient. The minimum inhibitory concentration (MIC) assay showed that Pa150 was resistant to almost all kinds of antibiotics, especially aminoglycosides. Whole genome sequencing revealed multiple antibiotic resistant genes on the chromosome and a 437-Kb plasmid (named pTJPa150) that harbors conjugation-related genes. A conjugation assay verified its self-transmissibility. On the pTJPa150 plasmid, we identified a 16S rRNA methylase gene, rmtB, that is flanked by mobile genetic elements (MGEs). The transfer of the pTJPa150 plasmid or the cloning of the rmtB gene into the reference strain, PAO1, significantly increased the bacterial resistance to aminoglycoside antibiotics. To the best of our knowledge, this is the first report of an rmtB-carrying conjugative plasmid isolated from P. aeruginosa, revealing a novel possible transmission mechanism of the rmtB gene.

The spread of carbapenemase-producing (CP) Enterobacterales is currently a worldwide concern, especially in the elderly. Twelve CP-E. coli isolated from rectal swabs of colonized inpatients aged ≥65 years from four hospitals in two Italian cities (Milan and Rome) were analyzed by whole genome sequencing (WGS) to obtain multi-locus sequence typing (MLST), identification of carbapenemase-encoding genes, resistome, plasmid content, and virulence genes. MLST analysis showed the presence of 10 unrelated lineages: ST410 (three isolates from three different hospitals in two cities) and ST12, ST38, ST69, ST95, ST131, ST189, ST648, ST1288, and ST1598 (one isolate each). Most isolates (9/12, 75%) contained a serine-β-lactamase gene (5 blaKPC-3, 2 blaKPC-2, and 2 blaOXA-181), while three isolates harbored a metallo-β-lactamase gene (two blaNDM-5 and one blaVIM-1). In most CP-E. coli, the presence of more than one plasmid was observed, with the predominance of IncF. Several virulence genes were detected. All isolates contained genes enhancing the bacterial fitness, such as gad and terC, and all isolates but one, fimH, encoding type 1 fimbriae. In conclusion, CP-E. coli clones colonizing elderly patients showed heterogeneous genetic backgrounds. We recommend strict surveillance to monitor and prevent the spread of successful, high-risk clones in healthcare settings.

The emergence of multidrug-resistant (MDR) bacterial strains is one of the significant global challenges with regard to bacterial drug-resistance control. Enterobacter hormaechei organisms belong to the Enterobacter cloacae complex (ECC) and are commonly recognized as causative agents for hospital infections. Recently, a few E. hormaechei MDR strains associated with infection in piglets, calves, and a fox were reported, highlighting the important role of animals and livestock in the emergence and spread of antimicrobial resistance. In this study, the vaginal swab sample from a 5-year-old cow with multiple anamnestic infectious abortions was carefully investigated. The animal was unresponsive to antibiotic therapy recommended by the veterinarian. The MDR bacterial strain isolated from the bovine sample, designated as the Saratov_2019, belonged to Enterobacter hormaechei. The genome-based phylogenetic analysis identified the isolate to be Enterobacter hormaechei subsp. xiangfangensis. The genome of the Saratov_2019 contained a 6364 bp plasmid. Importantly, we revealed the novel sequence type ST1416 and 13 MDR genes correlating with the MDR phenotype in only the chromosome but not the plasmid. These findings indicate that the potential spread of this strain may pose a threat for both animal and human health. The data obtained here support the notion of the important role of livestock in the emergence and spread of antimicrobial resistance, promoting careful investigation of the MDR spectra for livestock-related bacterial isolates. To the best of our knowledge, this is the first report on the association of E. hormaechei subsp. xiangfangensis with the infection of the reproductive system in cattle.

Staphylococcus aureus is an opportunistic bacterium known to cause severe infections in humans and animals. It is one of the major bacteria causing subclinical and clinical mastitis, leading to significant economic losses in livestock industry. In this study, we have isolated and characterized 80 S. aureus clinical isolates from mastitis-infected animals. The analysis of antimicrobial susceptibility, molecular typing, biofilm production and genetic determinants was performed to understand molecular and phenotypic features of the prevalent pathogen. Our antibiotic susceptibility assays showed the majority (57.5%) of isolates to be multidrug-resistant (MDR), 38.75% resistant and 3.75% sensitive. We found 25% isolates to be methicillin-resistant S. aureus (MRSA) based on oxacillin susceptibility assays. In the MRSA group, maximum isolates (95%) were MDR compared to 45% in MSSA. Multilocus sequence typing (MLST) revealed 15 different STs; ST-97 was the most common ST, followed by ST-2459, ST-1, ST-9 and ST-72. The agr typing showed agr-I as the most common type, followed by type II and III. Most isolates developed biofilms, which ranged in intensity from strong to weak. The presence or absence of lukS, a virulence-related gene, was found to have a substantial relationship with the biofilm phenotype. However, no significant association was found between biofilm formation and antimicrobial resistance or other virulence genes. We also found four MRSA isolates that were mecA negative based on molecular assays. Our findings reveal the prevalence of multidrug-resistant S. aureus clinical isolates in India that are biofilm positive and have critical genetic factors for disease pathogenesis causing bovine mastitis. This study emphasizes the need for the comprehensive surveillance of S. aureus and other mastitis-causing pathogens to control the disease effectively.

Aquatic environments are recognized as one of the main reservoirs for the emergence and dissemination of high-risk lineages of multidrug-resistant (MDR) bacteria of public health concern. However, the genomic characteristics of antibiotic-resistant Escherichia coli isolates from aquatic origins remain limited. Herein, we examined the antibiotic resistance and virulence genomic profiles of three E. coli recovered from surface water in northwest Mexico. Antimicrobial susceptibility testing, whole-genome sequencing (WGS), and in-depth in silico analysis were performed. Two E. coli exhibited MDR phenotypes. WGS-based typing revealed genetic diversity, and phylogenetic analysis corroborated a notable divergent relationship among the studied E. coli. One E. coli strain, harboring enterotoxigenic and extraintestinal pathogenic-associated virulence genes, was assigned to the ST4 lineage. MDR E. coli, belonging to the international high-risk clones ST410 and ST617, carried genes and mutations conferring resistance to aminoglycosides, β-lactams, quinolones, sulfonamides, tetracyclines, and trimethoprim. This study describes, for the first time, the detection and genomic profiling of high-risk lineages of E. coli ST410 and ST617 from surface water in Mexico. Additionally, our results underscore the role of surface water as a reservoir for critical pathogenic and MDR E. coli clones and the need for the surveillance and monitoring of aquatic environments via WGS from the One Health perspective.

Antibiotic resistance in pneumococci contributes to the high pneumococcal deaths in children. We assessed the molecular characteristics of multidrug-resistant (MDR) pneumococci isolated from healthy vaccinated children under five years of age in Cape Coast, Ghana. A total of 43 MDR isolates were selected from 151 pneumococcal strains obtained from nasopharyngeal carriage. All isolates were previously serotyped by multiplex PCR and Quellung reaction. Susceptibility testing was performed using either the E-test or disk diffusion method. Virulence and antibiotic resistance genes were identified by PCR. Molecular epidemiology was analyzed using multilocus sequence typing (MLST). Vaccine-serotypes 23F and 19F were predominant. The lytA and pavB virulence genes were present in all isolates, whiles 14–86% of the isolates carried pilus-islets 1 and 2, pcpA, and psrP genes. Penicillin, tetracycline, and cotrimoxazole resistance were evident in >90% of the isolates. The ermB, mefA, and tetM genes were detected in (n = 7, 16.3%), (n = 4, 9.3%) and (n = 43, 100%) of the isolates, respectively. However, >60% showed alteration in the pbp2b gene. MLST revealed five novel and six known sequence types (STs). ST156 (Spain9V-3) and ST802 were identified as international antibiotic-resistant clones. The emergence of international-MDR clones in Ghana requires continuous monitoring of the pneumococcus through a robust surveillance system.

The emergence of multidrug-resistant bacterial pathogens has severely threatened global health. A phage with the ability to efficiently and specifically lyse bacteria is considered an alternative for controlling multidrug-resistant bacterial pathogens. The discovery of novel agents for controlling the infections caused by K. pneumoniae is urgent due to the broad multidrug-resistance of K. pneumoniae. Only a few phage isolates have been reported to infect multidrug-resistant K. pneumoniae. In this study, by using the multidrug-resistant K. pneumoniae strain as an indicator, a novel phage called vB_KleS-HSE3, which maintains high antibacterial activity and high physical stability, was isolated from hospital sewage. This phage infected one of four tested multidrug-resistant K. pneumoniae strains. This phage belongs to the Siphoviridae family and a comparative genomic analysis showed that this phage is part of a novel phage lineage among the Siphoviridae family of phages that infect strains of Klebsiella. Based on its features, the vB_KleS-HSE3 phage has potential for controlling infections caused by multidrug-resistant K. pneumoniae.

On 18 August 2019, an article was published in Microorganisms presenting novel, approved anti-Gram-positive antibiotics. On 19 August 2019, the U.S. Food and Drug Administration announced the approval of lefamulin, a representative of a new class of antibiotics, the pleuromutilins, for the treatment of adult community-acquired bacterial pneumonia. We present a brief description of lefamulin.

Increasing multidrug-resistance to Gram-positive pathogens, particularly to staphylococci, enterococci and streptococci, is a major problem, resulting in significant morbidity, mortality and healthcare costs. In recent years, only a small number of novel antibiotics effective against Gram-positive bacteria has been approved. This review will discuss the current evidence for novel branded antibiotics that are highly effective in the treatment of multidrug-resistant infections by Gram-positive pathogens, namely ceftobiprole, ceftaroline, telavancin, oritavancin, dalbavancin, tedizolid, besifloxacin, delafloxacin, ozenoxacin, and omadacycline. The mechanism of action, pharmacokinetics, microbiological spectrum, efficacy and safety profile will be concisely presented. As for any emerging antibiotic agent, resistance is likely to develop against these highly effective antibiotics. Only through appropriate dosing, utilization and careful resistance development monitoring will these novel antibiotics continue to treat Gram-positive pathogens in the future.

Periodontal disease is caused by different gram-negative anaerobic bacteria; however, Escherichia coli has also been isolated from periodontitis and its role in periodontitis is less known. This study aimed to determine the variability in virulence genotype, antibiotic resistance phenotype, biofilm formation, phylogroups, and serotypes in different emerging periodontal strains of Escherichia coli , isolated from patients with periodontal disease and healthy controls. E. coli , virulence genes, and phylogroups, were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, biofilm formation was quantified using polystyrene microtiter plates, and serotypes were determined by serotyping. Although E. coli was not detected in the controls ( n = 70), it was isolated in 14.7% (100/678) of the patients. Most of the strains ( n = 81/100) were multidrug-resistance. The most frequent adhesion genes among the strains were fimH and iha , toxin genes were usp and hlyA , iron-acquisition genes were fyuA and irp2, and protectin genes were ompT, and KpsMT . Phylogroup B2 and serotype O25:H4 were the most predominant among the strains. These findings suggest that E. coli may be involved in periodontal disease due to its high virulence, multidrug-resistance, and a wide distribution of phylogroups and serotypes.

Antibiotic resistance in pneumococci contributes to the high pneumococcal deaths in children. We assessed the molecular characteristics of multidrug-resistant (MDR) pneumococci isolated from healthy vaccinated children under five years of age in Cape Coast, Ghana. A total of 43 MDR isolates were selected from 151 pneumococcal strains obtained from nasopharyngeal carriage. All isolates were previously serotyped by multiplex PCR and Quellung reaction. Susceptibility testing was performed using either the E-test or disk diffusion method. Virulence and antibiotic resistance genes were identified by PCR. Molecular epidemiology was analyzed using multilocus sequence typing (MLST). Vaccine-serotypes 23F and 19F were predominant. The lytA and pavB virulence genes were present in all isolates, whiles 14–86% of the isolates carried pilus-islets 1 and 2, pcpA, and psrP genes. Penicillin, tetracycline, and cotrimoxazole resistance were evident in >90% of the isolates. The ermB, mefA, and tetM genes were detected in (n = 7, 16.3%), (n = 4, 9.3%) and (n = 43, 100%) of the isolates, respectively. However, >60% showed alteration in the pbp2b gene. MLST revealed five novel and six known sequence types (STs). ST156 (Spain9V-3) and ST802 were identified as international antibiotic-resistant clones. The emergence of international-MDR clones in Ghana requires continuous monitoring of the pneumococcus through a robust surveillance system. [ABSTRACT FROM AUTHOR]

The emergence of multidrug-resistant bacterial pathogens has severely threatened global health. A phage with the ability to efficiently and specifically lyse bacteria is considered an alternative for controlling multidrug-resistant bacterial pathogens. The discovery of novel agents for controlling the infections caused by K. pneumoniae is urgent due to the broad multidrug-resistance of K. pneumoniae. Only a few phage isolates have been reported to infect multidrug-resistant K. pneumoniae. In this study, by using the multidrug-resistant K. pneumoniae strain as an indicator, a novel phage called vB_KleS-HSE3, which maintains high antibacterial activity and high physical stability, was isolated from hospital sewage. This phage infected one of four tested multidrug-resistant K. pneumoniae strains. This phage belongs to the Siphoviridae family and a comparative genomic analysis showed that this phage is part of a novel phage lineage among the Siphoviridae family of phages that infect strains of Klebsiella. Based on its features, the vB_KleS-HSE3 phage has potential for controlling infections caused by multidrug-resistant K. pneumoniae. [ABSTRACT FROM AUTHOR]

On 18 August 2019, an article was published in Microorganisms presenting novel, approved anti-Gram-positive antibiotics. On 19 August 2019, the U.S. Food and Drug Administration announced the approval of lefamulin, a representative of a new class of antibiotics, the pleuromutilins, for the treatment of adult community-acquired bacterial pneumonia. We present a brief description of lefamulin. [ABSTRACT FROM AUTHOR]

Increasing multidrug-resistance to Gram-positive pathogens, particularly to staphylococci, enterococci and streptococci, is a major problem, resulting in significant morbidity, mortality and healthcare costs. In recent years, only a small number of novel antibiotics effective against Gram-positive bacteria has been approved. This review will discuss the current evidence for novel branded antibiotics that are highly effective in the treatment of multidrug-resistant infections by Gram-positive pathogens, namely ceftobiprole, ceftaroline, telavancin, oritavancin, dalbavancin, tedizolid, besifloxacin, delafloxacin, ozenoxacin, and omadacycline. The mechanism of action, pharmacokinetics, microbiological spectrum, efficacy and safety profile will be concisely presented. As for any emerging antibiotic agent, resistance is likely to develop against these highly effective antibiotics. Only through appropriate dosing, utilization and careful resistance development monitoring will these novel antibiotics continue to treat Gram-positive pathogens in the future. [ABSTRACT FROM AUTHOR]