# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 5731 | 0 | 1.0000 | Emergence of Third-Generation Cephalosporin-Resistant Morganella morganii in a Captive Breeding Dolphin in South Korea. The emergence of antimicrobial resistant (AMR) strains of Morganella morganii is increasingly being recognized. Recently, we reported a fatal M. morganii infection in a captive bottlenose dolphin (Tursiops truncatus) bred at a dolphinarium in South Korea. According to our subsequent investigations, the isolated M. morganii strain KC-Tt-01 exhibited extensive resistance to third-generation cephalosporins which have not been reported in animals. Therefore, in the present study, the genome of strain KC-Tt-01 was sequenced, and putative virulence and AMR genes were investigated. The strain had virulence and AMR genes similar to those of other M. morganii strains, including a strain that causes human sepsis. An amino-acid substitution detected at the 86th residue (Arg to Cys) of the protein encoded by ampR might explain the extended resistance to third-generation cephalosporins. These results indicate that the AMR M. morganii strain isolated from the captive dolphin has the potential to cause fatal zoonotic infections with antibiotic treatment failure due to extended drug resistance, and therefore, the management of antibiotic use and monitoring of the emergence of AMR bacteria are urgently needed in captive cetaceans for their health and conservation. | 2020 | 33171912 |
| 5519 | 1 | 0.9997 | 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 |
| 5518 | 2 | 0.9997 | Analysis of Resistance Gene Prevalence in Whole-Genome Sequenced Enterobacteriales from Brazil. Enterobacteriales is an order of bacteria responsible for community and hospital-acquired infections related to high rates of antimicrobial resistance and increased treatment costs, morbidity, and mortality globally. The aims of this study were to analyze the frequency of the resistance genes detected and distribution over the years and sources of isolation in sequenced Enterobacteriales strains isolated in Brazil and available at the Pathogen Detection website. The presence of resistance genes was analyzed in 1,507 whole-genome sequenced strains of 19 Enterobacteriales species. A total of 58.0% of the strains presented resistance genes to at least one antimicrobial class and 684 strains presented a multidrug-resistant (MDR) profile. Resistance genes to 14 classes of antimicrobials were detected. Aminoglycosides presented the most prevalent and diverse resistance genes, while the sulfonamide resistance gene, sul2, was the most prevalent among the strains studied. The presence of resistance genes from 14 different antimicrobial classes, the high levels of MDR strains, and the detection of genes related to clinical and veterinary-used drugs reinforce the necessity of more efficient control measures. Moreover, it warns for the necessity of the rational use of antimicrobials in veterinary and clinical situations in Brazil, since contaminated food may act as a vehicle for human infections. | 2020 | 31746671 |
| 1917 | 3 | 0.9997 | Prediction of major antibiotic resistance in Escherichia coli and Klebsiella pneumoniae in Singapore, USA and China using a limited set of gene targets. Antibiotic resistance in Gram-negative bacteria, especially Enterobacteriaceae, can be conferred by a large number of different acquired resistance genes, although it appears that relatively few dominate. A previous survey of Escherichia coli and Klebsiella pneumoniae isolates from Sydney, Australia, revealed that a limited set of genes could reliably predict resistance to third-generation cephalosporins (3GCs) and aminoglycosides. Here we tested E. coli and K. pneumoniae isolates with a cefotaxime, ceftriaxone and/or ceftazidime minimum inhibitory concentration of ≥ 2 μg/mL from China and Singapore, with significantly higher resistance rates than Australia, as well as the USA. Few targets were needed to predict non-susceptibility to 3GCs (95/95; 100%) and gentamicin (47/51; 92%). The gene types detected here are consistent with previous surveys in similar countries with similar resistance rates, where the majority of 3GC resistance can be explained by blaCTX-M genes. This study identified a limited set of genes capable of predicting resistance to 3GC and aminoglycoside antibiotics and implies a restriction in the global resistance gene pool that can be exploited for diagnostic purposes. | 2014 | 24721234 |
| 5508 | 4 | 0.9997 | 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 |
| 5501 | 5 | 0.9997 | The oral microbiota of domestic cats harbors a wide variety of Staphylococcus species with zoonotic potential. This study aimed to characterize the species, antimicrobial resistance and dispersion of CRISPR systems in staphylococci isolated from the oropharynx of domestic cats in Brazil. Staphylococcus strains (n=75) were identified by MALDI-TOF and sequencing of rpoB and tuf genes. Antimicrobial susceptibility was assessed by disk diffusion method and PCR to investigate the presence of antimicrobial-resistance genes usually present in mobile genetic elements (plasmids), in addition to plasmid extraction. CRISPR - genetic arrangements that give the bacteria the ability to resist the entry of exogenous DNA - were investigated by the presence of the essential protein Cas1 gene. A great diversity of Staphylococcus species (n=13) was identified. The presence of understudied species, like S. nepalensis and S. pettenkoferi reveals that more than one identification method may be necessary to achieve conclusive results. At least 56% of the strains contain plamids, being 99% resistant to at least one of the eight tested antimicrobials and 12% multidrug resistant. CRISPR were rare among the studied strains, consistent with their putative role as gene reservoirs. Moreover, herein we describe for the first time their existence in Staphylococcus lentus, to which the system must confer additional adaptive advantage. Prevalence of resistance among staphylococci against antimicrobials used in veterinary and human clinical practice and the zoonotic risk highlight the need of better antimicrobial management practices, as staphylococci may transfer resistance genes among themselves, including to virulent species, like S. aureus. | 2017 | 28284599 |
| 1971 | 6 | 0.9997 | Antibiotic resistance of bacteria in water containing ornamental fishes. Water containing ornamental fishes was found to frequently contain countable numbers of bacteria that were resistant to one or more antibiotic or chemotherapeutic agents. The multidrug-resistant strains most commonly isolated were lactose-fermenting Citrobacter freundii. The overall resistance of these aquaria strains was greater than the previously described resistance of clinical isolates of C. freundii. Although the strains examined appeared to lack R-factors, this pool of resistant bacteria may have public health implications. | 1976 | 988781 |
| 5676 | 7 | 0.9997 | Fosfomycin Resistance in Bacteria Isolated from Companion Animals (Dogs and Cats). Fosfomycin is an old antibacterial agent, which is currently used mainly in human medicine, in uncomplicated Urinary Tract Infections (UTIs). The purpose of this review is to investigate the presence and the characteristics of Fosfomycin resistance in bacteria isolated from canine or feline samples, estimate the possible causes of the dissemination of associated strains in pets, and underline the requirements of prospective relevant studies. Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines were used for the search of current literature in two databases. A total of 33 articles were finally included in the review. Relevant data were tracked down, assembled, and compared. Referring to the geographical distribution, Northeast Asia was the main area of origin of the studies. E. coli was the predominant species detected, followed by other Enterobacteriaceae, Staphylococci, and Pseudomonas spp. FosA and fosA3 were the more frequently encountered Antimicrobial Resistance Genes (ARGs) in the related Gram-negative isolates, while fosB was regularly encountered in Gram-positive ones. The majority of the strains were multidrug-resistant (MDR) and co-carried resistance genes against several classes of antibiotics and especially β-Lactams, such as bla(CTX-M) and mecA. These results demonstrate the fact that the cause of the spreading of Fosfomycin-resistant bacteria among pets could be the extended use of other antibacterial agents, that promote the prevalence of MDR, epidemic strains among an animal population. Through the circulation of these strains into a community, a public health issue could arise. Further research is essential though, for the comprehensive consideration of the issue, as the current data are limited. | 2023 | 37235420 |
| 5712 | 8 | 0.9997 | Draft Genome Sequences of Three Multidrug-Resistant Staphylococcus spp. Isolated from Hospital Wastewater in Malaysia. Staphylococcus spp. are Gram-positive bacteria that reside within the normal microbiota of humans and animals but pose a health threat as reservoirs of antimicrobial resistance genes. Here, we present the draft genome sequences of three Staphylococcus sp. strains isolated from hospital wastewater in Malaysia that demonstrated resistance to multiple antibiotics. | 2021 | 33958405 |
| 5682 | 9 | 0.9997 | 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 |
| 4967 | 10 | 0.9996 | Whole-genome sequencing of toxigenic Clostridioides difficile reveals multidrug resistance and virulence genes in strains of environmental and animal origin. BACKGROUND: Clostridioides difficile has been recognized as an emerging pathogen in both humans and animals. In this context, antimicrobial resistance plays a major role in driving the spread of this disease, often leading to therapeutic failure. Moreover, recent increases in community-acquired C. difficile infections have led to greater numbers of investigations into the animal origin of the disease. The aim of this study was to evaluate the genetic similarities between 23 environmental and animal isolates by using whole-genome sequencing and to determine antimicrobial resistance and virulence factor genes in toxigenic C. difficile strains to provide important data for the development of diagnostic methods or treatment guidelines. RESULTS: The most common sequence type was ST11 (87%), followed by ST2 (9%) and ST19 (4%). In addition, 86.95% of the strains exhibited multidrug resistance, with antimicrobial resistance to mainly aminoglycosides, fluoroquinolones, tetracycline and B-lactams; nevertheless, one strain also carried other resistance genes that conferred resistance to lincosamide, macrolides, streptogramin a, streptogramin b, pleuromutilin, oxazolidinone and amphenicol. In addition, a wide range of virulence factor genes, such as those encoding adherence factors, exoenzymes and toxins, were found. However, we observed variations between toxinotypes, ribotypes and sequence types. CONCLUSIONS: The results of this study demonstrated significant genetic similarity between ST11 strains isolated from environmental sampling and from animal origin; these strains may represent a reservoir for community-acquired C. difficile infection, which is becoming a growing public health threat due to the development of multridug resistant (MDR) bacteria and the number of virulence factors detected. | 2024 | 39434132 |
| 4955 | 11 | 0.9996 | Evidence of extensive interspecies transfer of integron-mediated antimicrobial resistance genes among multidrug-resistant Enterobacteriaceae in a clinical setting. Multidrug resistance in gram-negative bacteria appears to be primarily the result of the acquisition of resistance genes by horizontal transfer. To what extent horizontal transfer may be responsible for the emergence of multidrug resistance in a clinical setting, however, has rarely been investigated. Therefore, the integron contents of isolates collected during a nosocomial outbreak of genotypically unrelated multidrug-resistant Enterobacteriaceae were characterized. The integron was chosen as a marker of transfer because of its association with multiresistance. Some genotypically identical isolates harbored different integrons. Grouping patients carrying the same integron yielded 6 epidemiologically linked clusters, with each cluster representing a different integron. Several patients carried multiple species harboring the same integron. Conjugation experiments with these strains resulted in the transfer of complete resistance patterns at high frequencies (10(-2) to 10(-4)). These findings provide strong evidence that the horizontal transfer of resistance genes contributed largely to the emergence of multidrug-resistant Enterobacteriaceae in this clinical setting. | 2002 | 12089661 |
| 5978 | 12 | 0.9996 | 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 |
| 5561 | 13 | 0.9996 | Antimicrobial Resistance of Escherichia coli and Pseudomonas aeruginosa from Companion Birds. Antimicrobial resistance is a public health concern worldwide and it is largely attributed to the horizontal exchange of transferable genetic elements such as plasmids carrying integrons. Several studies have been conducted on livestock showing a correlation between the systemic use of antibiotics and the onset of resistant bacterial strains. In contrast, although companion birds are historically considered as an important reservoir for human health threats, little information on the antimicrobial resistance in these species is available in the literature. Therefore, this study was aimed at evaluating the antimicrobial resistance of Escherichia coli and Pseudomonasaeruginosa isolated from 755 companion birds. Cloacal samples were processed for E. coli and P. aeruginosa isolation and then all isolates were submitted to antimicrobial susceptibility testing. P. aeruginosa was isolated in 59/755 (7.8%) samples, whereas E. coli was isolated in 231/755 (30.7%) samples. Most strains showed multidrug resistance. This study highlights that companion birds may act as substantial reservoirs carrying antimicrobial resistance genes which could transfer directly or indirectly to humans and animals, and from a One Health perspective this risk should not be underestimated. | 2020 | 33171927 |
| 5721 | 14 | 0.9996 | One Health Genomic Surveillance of Escherichia coli Demonstrates Distinct Lineages and Mobile Genetic Elements in Isolates from Humans versus Livestock. Livestock have been proposed as a reservoir for drug-resistant Escherichia coli that infect humans. We isolated and sequenced 431 E. coli isolates (including 155 extended-spectrum β-lactamase [ESBL]-producing isolates) from cross-sectional surveys of livestock farms and retail meat in the East of England. These were compared with the genomes of 1,517 E. coli bacteria associated with bloodstream infection in the United Kingdom. Phylogenetic core genome comparisons demonstrated that livestock and patient isolates were genetically distinct, suggesting that E. coli causing serious human infection had not directly originated from livestock. In contrast, we observed highly related isolates from the same animal species on different farms. Screening all 1,948 isolates for accessory genes encoding antibiotic resistance revealed 41 different genes present in variable proportions in human and livestock isolates. Overall, we identified a low prevalence of shared antimicrobial resistance genes between livestock and humans based on analysis of mobile genetic elements and long-read sequencing. We conclude that within the confines of our sampling framework, there was limited evidence that antimicrobial-resistant pathogens associated with serious human infection had originated from livestock in our region.IMPORTANCE The increasing prevalence of E. coli bloodstream infections is a serious public health problem. We used genomic epidemiology in a One Health study conducted in the East of England to examine putative sources of E. coli associated with serious human disease. E. coli from 1,517 patients with bloodstream infections were compared with 431 isolates from livestock farms and meat. Livestock-associated and bloodstream isolates were genetically distinct populations based on core genome and accessory genome analyses. Identical antimicrobial resistance genes were found in livestock and human isolates, but there was limited overlap in the mobile elements carrying these genes. Within the limitations of sampling, our findings do not support the idea that E. coli causing invasive disease or their resistance genes are commonly acquired from livestock in our region. | 2019 | 30670621 |
| 5577 | 15 | 0.9996 | Study on Bacteria Isolates and Antimicrobial Resistance in Wildlife in Sicily, Southern Italy. Wild environments and wildlife can be reservoirs of pathogens and antibiotic resistance. Various studies have reported the presence of zoonotic bacteria, resistant strains, and genetic elements that determine antibiotic resistance in wild animals, especially near urban centers or agricultural and zootechnical activities. The purpose of this study was the analysis, by cultural and molecular methods, of bacteria isolated from wild animals in Sicily, Italy, regarding their susceptibility profile to antibiotics and the presence of antibiotic resistance genes. Bacteriological analyses were conducted on 368 wild animals, leading to the isolation of 222 bacterial strains identified by biochemical tests and 16S rRNA sequencing. The most isolated species was Escherichia coli, followed by Clostridium perfringens and Citrobacter freundii. Antibiograms and the determination of resistance genes showed a reduced spread of bacteria carrying antibiotic resistance among wild animals in Sicily. However, since several wild animals are becoming increasingly close to residential areas, it is important to monitor their health status and to perform microbiological analyses following a One Health approach. | 2021 | 33478101 |
| 5642 | 16 | 0.9996 | Identification and antimicrobial susceptibility of obligate anaerobic bacteria from clinical samples of animal origin. The etiology of veterinary infectious diseases has been the focus of considerable research, yet relatively little is known about the causative agents of anaerobic infections. Susceptibility studies have documented the emergence of antimicrobial resistance and indicate distinct differences in resistance patterns related to veterinary hospitals, geographic regions, and antibiotic-prescribing regimens. The aim of the present study was to identify the obligate anaerobic bacteria from veterinary clinical samples and to determinate the in vitro susceptibility to eight antimicrobials and their resistance-associated genes. 81 clinical specimens obtained from food-producing animals, pets and wild animals were examined to determine the relative prevalence of obligate anaerobic bacteria, and the species represented. Bacteroides spp, Prevotella spp and Clostridium spp represented approximately 80% of all anaerobic isolates. Resistance to metronidazole, clindamycin, tetracycline and fluoroquinolones was found in strains isolated from food-producing animals. Ciprofloxacin, enrofloxacin and cephalotin showed the highest resistance in all isolates. In 17%, 4% and 14% of tetracycline-resistant isolates, the resistance genes tetL, tetM and tetW were respectively amplified by PCR whereas in 4% of clindamycin-resistant strains the ermG gene was detected. 26% of the isolates were positive for cepA, while only 6% harbored the cfxA (resistance-conferring genes to beta-lactams). In this study, the obligate anaerobic bacteria from Costa Rica showed a high degree of resistance to most antimicrobials tested. Nevertheless, in the majority of cases this resistance was not related to the resistance acquired genes usually described in anaerobes. It is important to address and regulate the use of antimicrobials in the agricultural industry and the empirical therapy in anaerobic bacterial infections in veterinary medicine, especially since antibiotics and resistant bacteria can persist in the environment. | 2015 | 26385434 |
| 1931 | 17 | 0.9996 | 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 |
| 1572 | 18 | 0.9996 | Phenotypic and Genomic Characterization of AmpC-Producing Klebsiella pneumoniae From Korea. The prevalence of multidrug-resistant gram-negative bacteria has continuously increased over the past few years; bacterial strains producing AmpC β-lactamases and/or extended-spectrum β-lactamases (ESBLs) are of particular concern. We combined high-resolution whole genome sequencing and phenotypic data to elucidate the mechanisms of resistance to cephamycin and β-lactamase in Korean Klebsiella pneumoniae strains, in which no AmpC-encoding genes were detected by PCR. We identified several genes that alone or in combination can potentially explain the resistance phenotype. We showed that different mechanisms could explain the resistance phenotype, emphasizing the limitations of the PCR and the importance of distinguishing closely-related gene variants. | 2018 | 29611388 |
| 4609 | 19 | 0.9996 | The importance of integrons for development and propagation of resistance in Shigella: the case of Latin America. In Latin America, the disease burden of shigellosis is found to coexist with the rapid and rampant spread of resistance to commonly used antibiotics. The molecular basis of antibiotic resistance lies within genetic elements such as plasmids, transposons, integrons, genomic islands, etc., which are found in the bacterial genome. Integrons are known to acquire, exchange, and express genes within gene cassettes and it is hypothesized that they play a significant role in the transmission of multidrug resistance genes in several Gram-negative bacteria including Shigella. A few studies have described antibiotic resistance genes and integrons among multidrug resistant Shigella isolates found in Latin America. For example, in Brazil, Bolivia, Chile, Costa Rica and Peru, class 1 and class 2 integrons have been detected among multidrug resistant strains of Shigella; this phenomenon is more frequently observed in S. flexneri isolates that are resistant to trimethoprim, sulfamethoxazole, streptomycin, ampicillin, chloramphenicol, and tetracycline. The gene cassette sul2, which is frequently detected in Shigella strains resistant to the sulfonamides, suggests that the sulfonamide-resistant phenotype can be explained by the presence of the sul2 genes independent of the integron class detected. It is to be noted that sul3 was negative in all isolates analyzed in these studies. The high frequency of sulfonamide (as encoded by sul2) and trimethoprim resistance is likely to be a result of the recurrent use of trimethoprim sulfamethoxazole as a popular regimen for the treatment of shigellosis. The observed resistance profiles of Shigella strains confirm that ampicillin and trimethoprim-sulfamethoxazole are ineffective as therapeutic options. In-depth information regarding antibiotic resistance mechanism in this pathogen is needed in order to develop suitable intervention strategies. There is a pressing need for regional and local antimicrobial resistance profiling of Shigella to be included as a part of the public health strategy. | 2016 | 27528086 |