# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 5508 | 0 | 1.0000 | Genomic and phenotypic comparison of environmental and patient-derived isolates of Pseudomonas aeruginosa suggest that antimicrobial resistance is rare within the environment. Patient-derived isolates of the opportunistic pathogen Pseudomonas aeruginosa are frequently resistant to antibiotics due to the presence of sequence variants in resistance-associated genes. However, the frequency of antibiotic resistance and of resistance-associated sequence variants in environmental isolates of P. aeruginosa has not been well studied. Antimicrobial susceptibility testing (ciprofloxacin, ceftazidime, meropenem, tobramycin) of environmental (n=50) and cystic fibrosis (n=42) P. aeruginosa isolates was carried out. Following whole genome sequencing of all isolates, 25 resistance-associated genes were analysed for the presence of likely function-altering sequence variants. Environmental isolates were susceptible to all antibiotics with one exception, whereas patient-derived isolates had significant frequencies of resistance to each antibiotic and a greater number of likely resistance-associated genetic variants. These findings indicate that the natural environment does not act as a reservoir of antibiotic-resistant P. aeruginosa, supporting a model in which antibiotic susceptible environmental bacteria infect patients and develop resistance during infection. | 2019 | 31553303 |
| 5510 | 1 | 0.9999 | Investigating possible association between multidrug resistance and isolate origin with some virulence factors of Escherichia coli strains isolated from infant faeces and fresh green vegetables. AIMS: In this study, the association between multidrug resistance (MDR) and the expression of some virulence factors were evaluated in Escherichia coli strains isolated from infant faeces and fresh green vegetables. The effect of isolate origin on associated virulence factors was evaluated. In addition, genetic fingerprinting of a sample of these isolates (10 isolates from each group) was studied in order to detect any genetic relatedness among these isolates. METHODS AND RESULTS: Escherichia coli isolates were divided into four groups based on their origin (human faeces or plant) and their antibiotic resistance (multiresistance or susceptible). PCR was used to investigate heat-labile and heat-stable enterotoxin genes, and four siderophore genes (aerobactin, enterobactin, salmochelin and yersiniabactin). Genetic fingerprinting of the isolates was performed using enterobacterial repetitive intergenic consensus PCR. Siderophore production was measured by a colorimetric method. Biofilm formation was evaluated by a crystal violet assay. The results of the study showed that the expression of MDR is not significantly associated with an increase in these virulence factors or with biofilm formation. However, the origin of isolates had a significant association with siderophore gene availability and consequently on the concentrations of siderophores released. Genetic fingerprinting indicated that human and plant isolates have the same clonal origin, suggesting their circulation among humans and plants. CONCLUSION: Antibiotic-susceptible strains of E. coli may be as virulent as MDR strains. Results also suggest that the environment can play a potential role in selection of strains with specific virulence factors. SIGNIFICANCE AND IMPACT OF THE STUDY: Antibiotic-susceptible isolates of Escherichia coli from plant or human origin can be as virulent as the multidrug resistance (MDR) ones. Genetic relatedness was detected among the isolates of plant and human origin, indicating the circulation of these bacteria among human and plants. This could imply a potential role for environmental antimicrobial resistant bacteria in human infection. | 2019 | 31034123 |
| 5509 | 2 | 0.9999 | Exploring Virulence Characteristics of Clinical Escherichia coli Isolates from Greece. The aim of this study was to examine the genetic characteristics that could be associated with the virulence characteristics of Escherichia coli collected from clinical samples. A collection of 100 non-repetitive E. coli isolates was analyzed. All isolates were typed by MLST. String production, biofilm formation and serum resistance were examined for all isolates. Twenty E. coli isolates were completely sequenced Illumina platform. The results showed that the majority of E. coli isolates (87%) produced significant levels of biofilm, while none of the isolates were positive for string test and resistance to serum. Additionally, the presence of CRISPR/Cas systems (type I-E or I-F) was found in 18% of the isolates. Analysis of WGS data found that all sequenced isolates harbored a variety of virulence genes that could be implicated in adherence, invasion, iron uptake. Also, WGS data confirmed the presence of a wide variety of resistance genes, including ESBL- and carbapenemase-encoding genes. In conclusion, an important percentage (87%) of the E. coli isolates had a significant ability to form biofilm. Biofilms, due to their heterogeneous nature and ability to make microorganisms tolerant to multiple antimicrobials, complicate treatment strategies. Thus, in combination with the presence of multidrug resistance, expression of virulence factors could challenge antimicrobial therapy of infections caused by such bacteria. | 2025 | 40731998 |
| 5672 | 3 | 0.9999 | Antibiotic Resistance, Biofilm Formation, and Presence of Genes Encoding Virulence Factors in Strains Isolated from the Pharmaceutical Production Environment. The spread of bacterial resistance to antibiotics affects various areas of life. The aim of this study was to assess the occurrence of Pseudomonas aeruginosa, and other bacteria mainly from orders Enterobacterales and Staphylococcus in the pharmaceutical production sites, and to characterize isolated strains in the aspects of antibiotic resistance, biofilm formation, and presence of genes encoding virulence factors. Genes encoding selected virulence factors were detected using PCR techniques. Antimicrobial susceptibility testing was applied in accordance with the EUCAST recommendations. A total of 46 P. aeruginosa strains were isolated and 85% strains showed a strong biofilm-forming ability. The qualitative identification of genes taking part in Quorum Sensing system demonstrated that over 89% of strains contained lasR and rhlI genes. An antimicrobial susceptibility testing revealed nine strains resistant to at least one antibiotic, and two isolates were the metallo-β-lactamase producers. Moreover, the majority of P. aeruginosa strains contained genes encoding various virulence factors. Presence of even low level of pathogenic microorganisms or higher level of opportunistic pathogens and their toxic metabolites might result in the production inefficiency. Therefore, the prevention of microbial contamination, effectiveness of sanitary and hygienic applied protocols, and constant microbiological monitoring of the environment are of great importance. | 2021 | 33513933 |
| 5673 | 4 | 0.9999 | Antimicrobial Resistance, Genetic Lineages, and Biofilm Formation in Pseudomonas aeruginosa Isolated from Human Infections: An Emerging One Health Concern. Pseudomonas aeruginosa (PA) is a leading nosocomial pathogen and has great versatility due to a complex interplay between antimicrobial resistance and virulence factors. PA has also turned into one the most relevant model organisms for the study of biofilm-associated infections. The objective of the study focused on analyzing the antimicrobial susceptibility, resistance genes, virulence factors, and biofilm formation ability of thirty-two isolates of PA. PA isolates were characterized by the following analyses: susceptibility to 12 antimicrobial agents, the presence of resistance genes and virulence factors in PCR assays, and the quantification of biofilm production as evaluated by two distinct assays. Selected PA isolates were analyzed through multilocus sequence typing (MLST). Thirty PA isolates have a multi-resistant phenotype, and most of the isolates showed high levels of resistance to the tested antibiotics. Carbapenems showed the highest prevalence of resistance. Various virulence factors were detected and, for the quantification of biofilm production, the effectiveness of different methods was assessed. The microtiter plate method showed the highest accuracy and reproducibility for detecting biofilm-producing bacteria. MLST revealed four distinct sequence types (STs) in clinical PA, with three of them considered high-risk clones of PA, namely ST175, ST235, and ST244. These clones are associated with multidrug resistance and are prevalent in hospitals worldwide. Overall, the study highlights the high prevalence of antibiotic resistance, the presence of carbapenemase genes, the diversity of virulence factors, and the importance of biofilm formation in PA clinical isolates. Understanding these factors is crucial for effective infection control measures and the development of targeted treatment strategies. | 2023 | 37627668 |
| 5519 | 5 | 0.9999 | Antimicrobial susceptibility, virulence potential and sequence types associated with Arcobacter strains recovered from human faeces. PURPOSE: The genus Arcobacter includes bacteria that are considered emergent pathogens because they can produce infections in humans and animals. The most common symptoms are bloody and non-bloody persistent diarrhea but cases with abdominal cramps without diarrhea or asymptomatic cases have also been described as well as cases with bacteremia. The objective was to characterize Arcobacter clinical strains isolated from the faeces of patients from three Spanish hospitals. METHODOLOGY: We have characterized 28 clinical strains (27 of A. butzleri and one of A. cryaerophilus) isolated from faeces, analysing their epidemiological relationship using the multilocus sequence typing (MLST) approach and screening them for their antibiotic susceptibility and for the presence of virulence genes.Results/Key findings. Typing results showed that only one of the 28 identified sequence types (i.e. ST 2) was already present in the MLST database. The other 27 STs constituted new records because they included new alleles for five of the seven genes or new combinations of known alleles of the seven genes. All strains were positive for the ciaB virulence gene and sensitive to tetracycline. However, 7.4 % of the A. butzleri and A. cryaerophilus strains showed resistance to ciprofloxacin. CONCLUSION: The fact that epidemiological unrelated strains show the same ST indicates that other techniques with higher resolution should be developed to effectively recognize the infection source. Resistance to ciprofloxacin, one of the antibiotics recommended for the treatment of Arcobacter intestinal infections, demonstrated in 10.7 % of the strains, indicates the importance of selecting the most appropriate effective treatment. | 2017 | 29120301 |
| 5513 | 6 | 0.9999 | The genetic background of antibiotic resistance among clinical uropathogenic Escherichia coli strains. The spreading mechanisms of antibiotic resistance are related to many bacterial and environment factors. The overuse of antibiotics is leading to an unceasing emergence of new multidrug resistant strains. This problem also concerns uropathogenic Escherichia coli strains, which is the most common pathogen causing urinary tract infections. The aim of this study was the genetic analysis of antibiotic resistance in comparison to the phenotypic background of E. coli strains. The characterized collection of E. coli strains isolated 10 years ago from the urine samples of patients with urinary tract infections was used for antimicrobial susceptibility testing (the disc diffusion method) and analysis of antibiotic resistance genes (PCR reaction, sequencing). Additionally, the presence of ESBL strains was analyzed. Fourteen genes were associated with resistance to beta-lactams, aminoglycosides, sulfonamides and quinolones. The genetic analysis revealed that bla(TEM-1) and sul2 were present in almost all of the studied strains. Other drug-resistance genes were very rare or non-existent. Otherwise, the phenotypic resistance to fluoroquinolones was well correlated with the genotypic background of the studied bacteria. The presence of particular genes and specific mutations indicate a high bacterial potential to multidrug resistance. On the other hand, it needs to be emphasized that the standard disk diffusion test for the routine antimicrobial susceptibility analysis is still the best way to estimate the current situation of bacterial drug-resistance. | 2018 | 30008141 |
| 4931 | 7 | 0.9999 | Delineating the Acquired Genetic Diversity and Multidrug Resistance in Alcaligenes from Poultry Farms and Nearby Soil. Alcaligenes faecalis is one of the most important and clinically significant environmental pathogens, increasing in importance due to its isolation from soil and nosocomial environments. The Gram-negative soil bacterium is associated with skin endocarditis, bacteremia, dysentery, meningitis, endophthalmitis, urinary tract infections, and pneumonia in patients. With emerging antibiotic resistance in A. faecalis, it has become crucial to understand the origin of such resistance genes within this clinically significant environmental and gut bacterium. In this research, we studied the impact of antibiotic overuse in poultry and its effect on developing resistance in A. faecalis. We sampled soil and faecal materials from five poultry farms, performed whole genome sequencing & analysis and identified four strains of A. faecalis. Furthermore, we characterized the genes in the genomic islands of A. faecalis isolates. We found four multidrug-resistant A. faecalis strains that showed resistance against vancomycin (MIC >1000 μg/ml), ceftazidime (50 μg/ml), colistin (50 μg/ml) and ciprofloxacin (50 μg/ml). From whole genome comparative analysis, we found more than 180 resistance genes compared to the reference sequence. Parts of our assembled contigs were found to be similar to different bacteria which included pbp1A and pbp2 imparting resistance to amoxicillin originally a part of Helicobacter and Bordetella pertussis. We also found the Mycobacterial insertion element IS6110 in the genomic islands of all four genomes. This prominent insertion element can be transferred and induce resistance to other bacterial genomes. The results thus are crucial in understanding the transfer of resistance genes in the environment and can help in developing regimes for antibiotic use in the food and poultry industry. | 2024 | 38904697 |
| 5671 | 8 | 0.9999 | Biofilms and antibiotic susceptibility of multidrug-resistant bacteria from wild animals. BACKGROUND: The "One Health" concept recognizes that human health and animal health are interdependent and bound to the health of the ecosystem in which they (co)exist. This interconnection favors the transmission of bacteria and other infectious agents as well as the flow of genetic elements containing antibiotic resistance genes. This problem is worsened when pathogenic bacteria have the ability to establish as biofilms. Therefore, it is important to understand the characteristics and behaviour of microorganisms in both planktonic and biofilms states from the most diverse environmental niches to mitigate the emergence and dissemination of resistance. METHODS: The purpose of this work was to assess the antibiotic susceptibility of four bacteria (Acinetobacter spp., Klebsiella pneumoniae, Pseudomonas fluorescens and Shewanella putrefaciens) isolated from wild animals and their ability to form biofilms. The effect of two antibiotics, imipenem (IPM) and ciprofloxacin (CIP), on biofilm removal was also assessed. Screening of resistance genetic determinants was performed by PCR. Biofilm tests were performed by a modified microtiter plate method. Bacterial surface hydrophobicity was determined by sessile drop contact angles. RESULTS: The susceptibility profile classified the bacteria as multidrug-resistant. Three genes coding for β-lactamases were detected in K. pneumoniae (TEM, SHV, OXA-aer) and one in P. fluorescens (OXA-aer). K. pneumoniae was the microorganism that carried more β-lactamase genes and it was the most proficient biofilm producer, while P. fluorescens demonstrated the highest adhesion ability. Antibiotics at their MIC, 5 × MIC and 10 × MIC were ineffective in total biofilm removal. The highest biomass reductions were found with IPM (54% at 10 × MIC) against K. pneumoniae biofilms and with CIP (40% at 10 × MIC) against P. fluorescens biofilms. DISCUSSION: The results highlight wildlife as important host reservoirs and vectors for the spread of multidrug-resistant bacteria and genetic determinants of resistance. The ability of these bacteria to form biofilms should increase their persistence. | 2018 | 29910986 |
| 5682 | 9 | 0.9999 | Reservoirs of resistance: polymyxin resistance in veterinary-associated companion animal isolates of Pseudomonas aeruginosa. BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen and a major cause of infections. Widespread resistance in human infections are increasing the use of last resort antimicrobials such as polymyxins. However, these have been used for decades in veterinary medicine. Companion animals are an understudied source of antimicrobial resistant P. aeruginosa isolates. This study evaluated the susceptibility of P. aeruginosa veterinary isolates to polymyxins to determine whether the veterinary niche represents a potential reservoir of resistance genes for pathogenic bacteria in both animals and humans. METHODS AND RESULTS: Clinical P. aeruginosa isolates (n=24) from UK companion animals were compared for antimicrobial susceptibility to a panel of human-associated isolates (n=37). Minimum inhibitory concentration (MIC) values for polymyxin B and colistin in the companion animals was significantly higher than in human isolates (P=0.033 and P=0.013, respectively). Genotyping revealed that the veterinary isolates were spread throughout the P. aeruginosa population, with shared array types from human infections such as keratitis and respiratory infections, suggesting the potential for zoonotic transmission. Whole genome sequencing revealed mutations in genes associated with polymyxin resistance and other antimicrobial resistance-related genes. CONCLUSION: The high levels of resistance to polymyxin shown here, along with genetic similarities between some human and animal isolates, together suggest a need for sustained surveillance of this veterinary niche as a potential reservoir for resistant, clinically relevant bacteria in both animals and humans. | 2019 | 31239295 |
| 5699 | 10 | 0.9999 | Presence of β-Lactamase Encoding Genes in Burkholderia cepacia Complex Isolated from Soil. Burkholderia cepacia complex has emerged as an important opportunistic bacteria group for immunocompromised patients, and it has a high level of intrinsic resistance for different antibiotic classes. Hydrolysis of β-lactam antibiotics by β-lactamases is the most common resistance mechanism in Gram-negative bacteria, and the presence of such enzymes complicates the selection of appropriate therapy. This study aimed at investigating the antimicrobial resistance profile and the presence of β-lactamase encoding genes in B. cepacia complex isolated from Brazilian soils. High-level ceftazidime resistance and several β-lactamase encoding genes were found, including the first report of bla(KPC) genes in bacteria isolated from soil. | 2018 | 28915359 |
| 5156 | 11 | 0.9999 | Pseudomonas aeruginosa strains isolated from animal with high virulence genes content and highly sensitive to antimicrobials. OBJECTIVES: P. aeruginosa is one of the most metabolically versatile bacteria having the ability to survive in multiple environments through its accessory genome. An important hallmark of P. aeruginosa is the high level of antibiotic resistance, which often makes eradication difficult and sometimes impossible. Evolutionary forces have led to this bacterium to develop high antimicrobial resistance with a variety of elements contributing to both intrinsic and acquired resistance. The objectives were to genetically and phenotypically characterizer P. aeruginosa strains isolated from companion animals of different species. METHODS: We characterized a collection of 39 P. aeruginosa strains isolated from infected animals. The genetic characterization was in relation to chromosomal profile by PFGE; content of virulence gene; presence of genomic islands (GIs); genes of the cytotoxins exported by T3SS: exoU, exoS, exoT and exoY; and type IV pili allele. The phenotypic characterization was based on patterns of susceptibility to different antimicrobials. RESULTS: Each strain had a PFGE profile, a high virulence genes content, and a large accessory genome. However, most of the strains presented high sensitivity to almost all antimicrobials tested, showing no acquired resistance (no β-lactamases). The exception to this lack of resistance was seen with penicillin. CONCLUSIONS: P. aeruginosa could be a naturally sensitive bacterium to standard antimicrobials but could rapidly develop intrinsic and acquired resistance when the bacterium is exposed to pressure exerted by antibiotics, as observed in hospital settings. | 2024 | 38452900 |
| 5511 | 12 | 0.9999 | Escherichia coli as a Potential Reservoir of Antimicrobial Resistance Genes on the Island of O'ahu. The problem of antimicrobial-resistant bacteria has not been adequately explored in the tropical island environment. To date, there has not been a systematic investigation into the prevalence and distribution of antimicrobial resistance determinants in the Hawaiian Islands. Urinary isolates are the most common bacterial pathogens encountered in the clinical laboratory. Therefore, the antimicrobial resistance determinant profiles of these organisms can serve as a sentinel of the overall antimicrobial resistance situation in a localized patient population. In this study, 82 clinical isolates of Escherichia coli derived from 82 distinct patients were collected at a large medical center on the island of O'ahu. Each isolate was evaluated for the presence of antimicrobial resistance genes using a microarray-based approach. A total of 36 antimicrobial resistance genes covering 10 classes of antimicrobial compounds were identified. Most isolates were found to harbor between 3 and 5 antimicrobial resistance genes. Only a few isolates were found to harbor more than 12 genes. Significantly, a high rate of phenotypic resistance to one of the first-line treatments for uncomplicated urinary tract infection (sulfamethoxazole) was identified. This phenotype was correlated to the presence of sulfonamides and trimethoprim resistance determinants. Since E. coli is one of the most encountered pathogens in the hospital environment, the presence of clinically relevant resistance determinants in isolates of this organism from a clinical setting on O'ahu is a significant finding that warrants further investigation. | 2021 | 33490961 |
| 5645 | 13 | 0.9999 | Antibiotic Resistance of Bacillus cereus in Plant Foods and Edible Wild Mushrooms in a Province. Bacillus cereus is a common pathogen causing foodborne diseases, secreting and producing a large number of toxins that can cause a variety of diseases and pose many threats to human health. In this study, 73 strains of Bacillus cereus were isolated and identified from six types of foods from seven different cities in a province, and the antibiotic-resistant phenotype was detected by using the Bauer-Kirby method. Results showed that the 73 isolates were completely sensitive to gentamicin and 100% resistant to chloramphenicol, in addition to which all strains showed varying degrees of resistance to 13 other common antibiotics, and a large number of strains resistant to multiple antibiotics were found. A bioinformatic analysis of the expression of resistance genes in Bacillus cereus showed three classes of antibiotic-resistant genes, which were three of the six classes of antibiotics identified according to the resistance phenotype. The presence of other classes of antibiotic-resistant genes was identified from genome-wide information. Antibiotic-resistant phenotypes were analyzed for correlations with genotype, and remarkable differences were found among the phenotypes. The spread of antibiotic-resistant strains is a serious public health problem that requires the long-term monitoring of antimicrobial resistance in Bacillus cereus, and the present study provides important information for monitoring antibiotic resistance in bacteria from different types of food. | 2023 | 38138092 |
| 5978 | 14 | 0.9998 | Evidences of gentamicin resistance amplification in Klebsiella pneumoniae isolated from faeces of hospitalized newborns. The intestinal microbiota, a barrier to the establishment of pathogenic bacteria, is also an important reservoir of opportunistic pathogens. It plays a key role in the process of resistance-genes dissemination, commonly carried by specialized genetic elements, like plasmids, phages, and conjugative transposons. We obtained from strains of enterobacteria, isolated from faeces of newborns in a university hospital nursery, indication of phenotypical gentamicin resistance amplification (frequencies of 10(-3) to 10(-5), compatible with transposition frequencies). Southern blotting assays showed strong hybridization signals for both plasmidial and chromosomal regions in DNA extracted from variants selected at high gentamicin concentrations, using as a probe a labeled cloned insert containing aminoglycoside modifying enzyme (AME) gene sequence originated from a plasmid of a Klebsiella pneumoniae strain previously isolated in the same hospital. Further, we found indications of inactivation to other resistance genes in variants selected under similar conditions, as well as, indications of co-amplification of other AME markers (amikacin). Since the intestinal environment is a scenario of selective processes due to the therapeutic and prophylactic use of antimicrobial agents, the processes of amplification of low level antimicrobial resistance (not usually detected or sought by common methods used for antibiotic resistance surveillance) might compromise the effectiveness of antibiotic chemotherapy. | 1999 | 10585658 |
| 1920 | 15 | 0.9998 | Exploring the resistome, virulome, and mobilome of multidrug-resistant Klebsiella pneumoniae isolates: deciphering the molecular basis of carbapenem resistance. BACKGROUND: Klebsiella pneumoniae, a notorious pathogen for causing nosocomial infections has become a major cause of neonatal septicemia, leading to high morbidity and mortality worldwide. This opportunistic bacterium has become highly resistant to antibiotics due to the widespread acquisition of genes encoding a variety of enzymes such as extended-spectrum beta-lactamases (ESBLs) and carbapenemases. We collected Klebsiella pneumoniae isolates from a local tertiary care hospital from February 2019-February 2021. To gain molecular insight into the resistome, virulome, and genetic environment of significant genes of multidrug-resistant K. pneumoniae isolates, we performed the short-read whole-genome sequencing of 10 K. pneumoniae isolates recovered from adult patients, neonates, and hospital tap water samples. RESULTS: The draft genomes of the isolates varied in size, ranging from 5.48 to 5.96 Mbp suggesting the genome plasticity of this pathogen. Various genes conferring resistance to different classes of antibiotics e.g., aminoglycosides, quinolones, sulfonamides, tetracycline, and trimethoprim were identified in all sequenced isolates. The highest resistance was observed towards carbapenems, which has been putatively linked to the presence of both class B and class D carbapenemases, bla(NDM,) and bla(OXA), respectively. Moreover, the biocide resistance gene qacEdelta1 was found in 6/10 of the sequenced strains. The sequenced isolates exhibited a broad range of sequence types and capsular types. The significant antibiotic resistance genes (ARGs) were bracketed by a variety of mobile genetic elements (MGEs). Various spontaneous mutations in genes other than the acquired antibiotic-resistance genes were observed, which play an indirect role in making these bugs resistant to antibiotics. Loss or deficiency of outer membrane porins, combined with ESBL production, played a significant role in carbapenem resistance in our sequenced isolates. Phylogenetic analysis revealed that the study isolates exhibited evolutionary relationships with strains from China, India, and the USA suggesting a shared evolutionary history and potential dissemination of similar genes amongst the isolates of different origins. CONCLUSIONS: This study provides valuable insight into the presence of multiple mechanisms of carbapenem resistance in K. pneumoniae strains including the acquisition of multiple antibiotic-resistance genes through mobile genetic elements. Identification of rich mobilome yielded insightful information regarding the crucial role of insertion sequences, transposons, and integrons in shaping the genome of bacteria for the transmission of various resistance-associated genes. Multi-drug resistant isolates that had the fewest resistance genes exhibited a significant number of mutations. K. pneumoniae isolate from water source displayed comparable antibiotic resistance determinants to clinical isolates and the highest number of virulence-associated genes suggesting the possible interplay of ARGs amongst bacteria from different sources. | 2024 | 38664636 |
| 5681 | 16 | 0.9998 | Molecular Epidemiology of Neonatal-Associated Staphylococcus haemolyticus Reveals Endemic Outbreak. Staphylococcus haemolyticus is a major cause of late-onset sepsis in neonates, and endemic clones are often multidrug-resistant. The bacteria can also act as a genetic reservoir for more pathogenic bacteria. Molecular epidemiology is important in understanding bacterial pathogenicity and preventing infection. To describe the molecular epidemiology of S. haemolyticus isolated from neonatal blood cultures at a Swedish neonatal intensive care unit (NICU) over 4 decades, including antibiotic resistance genes (ARGs), virulence factors, and comparison to international isolates. Isolates were whole-genome sequenced, and single nucleotide polymorphisms in the core genome were used to map the relatedness. The occurrence of previously described ARGs and virulence genes were investigated. Disc diffusion and gradient tests were used to determine phenotypic resistance. The results revealed a clonal outbreak of S. haemolyticus at this NICU during the 1990s. Multidrug resistance was present in 28 (82%) of all isolates and concomitant resistance to aminoglycoside and methicillin occurred in 27 (79%). No isolates were vancomycin resistant. Genes encoding ARGs and virulence factors occurred frequently. The isolates in the outbreak were more homogenous in their genotypic and phenotypic patterns. Genotypic and phenotypic resistance combinations were consistent. Pathogenic traits previously described in S. haemolyticus occurred frequently in the present isolates, perhaps due to the hospital selection pressure resulting in epidemiological success. The clonal outbreak revealed by this study emphasizes the importance of adhering to hygiene procedures in order to prevent future endemic outbreaks. IMPORTANCE This study investigated the relatedness of Staphylococcus haemolyticus isolated from neonatal blood and revealed a clonal outbreak in the 1990s at a Swedish neonatal intensive care unit. The outbreak clone has earlier been isolated in Japan and Norway. Virulence and antibiotic resistance genes previously associated with clinical S. haemolyticus were frequently occuring in the present study as well. The majority of the isolates were multidrug-resistant. These traits should be considered important for S. haemolyticus epidemiological success and are probably caused by the hospital selection pressure. Thus, this study emphasizes the importance of restrictive antibiotic use and following the hygiene procedures, to prevent further antibiotic resistance spread and future endemic outbreaks. | 2022 | 36314976 |
| 3393 | 17 | 0.9998 | Antibiotic resistance of gram-negative bacteria in rivers, United States. Bacteria with intrinsic resistance to antibiotics are found in nature. Such organisms may acquire additional resistance genes from bacteria introduced into soil or water, and the resident bacteria may be the reservoir or source of widespread resistant organisms found in many environments. We isolated antibiotic-resistant bacteria in freshwater samples from 16 U.S. rivers at 22 sites and measured the prevalence of organisms resistant to beta-lactam and non-beta-lactam antibiotics. Over 40% of the bacteria resistant to more than one antibiotic had at least one plasmid. Ampicillin resistance genes, as well as other resistance traits, were identified in 70% of the plasmids. The most common resistant organisms belonged to the following genera: Acinetobacter, Alcaligenes, Citrobacter, Enterobacter, Pseudomonas, and Serratia. | 2002 | 12095440 |
| 5640 | 18 | 0.9998 | Antibiotic consumption and faecal bacterial susceptibility in surgical in-patients. A one-day prevalence study of resistance of faecal bacteria to 19 antibacterial agents was performed in 144 surgical inpatients. Most of the drug-resistant isolates were of aerobic and anaerobic species commonly seen in infections, which indicates that surveys of faecal flora can yield rapid information on local patterns of drug resistance in pathogens relevant to abdominal infection. In faecal bacteria the drug resistance pattern only weakly reflected the local antibiotic consumption. The amount of administered aminoglycosides was relatively small, and no gentamicin-resistant aerobes were found. Absence of resistance was found also for some of the newer agents not yet in clinical use (aztreonam, latamoxef, norfloxacin), but not for others (ceftazidime, ceftriaxone). Despite heavy use of fosfomycin and metronidazole, resistance had not emerged among aerobic and anaerobic bacteria, respectively. Imipenem was unique in inhibiting growth of all aerobic and anaerobic faecal bacteria, in the studied patients with the single exception of a strain of Enterobacter. | 1987 | 3673450 |
| 1931 | 19 | 0.9998 | The level of antimicrobial resistance of sewage isolates is higher than that of river isolates in different Escherichia coli lineages. The dissemination of antimicrobial-resistant bacteria in environmental water is an emerging concern in medical and industrial settings. Here, we analysed the antimicrobial resistance of Escherichia coli isolates from river water and sewage by the use of a combined experimental phenotypic and whole-genome-based genetic approach. Among the 283 tested strains, 52 were phenotypically resistant to one or more antimicrobial agents. The E. coli isolates from the river and sewage samples were phylogenetically indistinguishable, and the antimicrobial-resistant strains were dispersedly distributed in a whole-genome-based phylogenetic tree. The prevalence of antimicrobial-resistant strains as well as the number of antimicrobials to which they were resistant were higher in sewage samples than in river samples. Antimicrobial resistance genes were more frequently detected in strains from sewage samples than in those from river samples. We also found that 16 river isolates that were classified as Escherichia cryptic clade V were susceptible to all the antimicrobials tested and were negative for antimicrobial resistance genes. Our results suggest that E. coli strains may acquire antimicrobial resistance genes more frequently and/or antimicrobial-resistant E. coli strains may have higher rates of accumulation and positive selection in sewage than in rivers, irrespective of their phylogenetic distribution. | 2020 | 33087784 |