scholarly journals Ciprofloxacin Induced Antibiotic Resistance in Salmonella Typhimurium Mutants and Genome Analysis

Author(s):  
Aarti Kakatkar ◽  
Anubrata Das ◽  
Ravindranath Shashidhar

Abstract Salmonella species is an important food-borne pathogen. Ciprofloxacin is used for treatment of salmonellosis. The wild type of Salmonella Typhimurium was exposed to 10-fold of minimal inhibitory concentration (MIC) of ciprofloxacin. The survivors of the first exposure were regrown. This regrown population was exposed to similar ciprofloxacin treatment. After 20 repetitions of the antibiotic exposure, the survival population was evaluated for antibiotic resistance. The mutants had 100-fold more of the initial MIC. The mutants were of smaller size (0.7 ± 0.5 mm) with a lag phase of 70 min. These mutants were resistant to other antibiotics belonging to different classes but were sensitive to heat and osmotic stress. The whole genome sequencing (WGS) analysis of antibiotic resistant mutants revealed interesting mutation pattern. Total 40513 mutations were observed across the genome (total 3843 annotated genes). Relatively small percentage (5.2%) of mutations were non-synonymous. Four-fold more transitions were observed than transversions. Ratio of <1 transition vs transversion shows a positive selection for antibiotic resistant trait. Seven genes with over 50 mutations were observed. However, mutation distribution across the genome was relatively uniform. The important genes like dnaE, gyrA, iroC, metH and rpoB involved in antibiotic resistance had point mutations. The genome analysis showed that most affected pathways were transcription regulation, transmembrane transport, cell adhesion, pathogenesis, pilus assembly, oxidation-reduction mechanisms, phosphor-relay signal transduction and LPS biosynthesis. We propose that development resistance to ciprofloxacin is because of the mutations in these genes.

2020 ◽  
Vol 9 (20) ◽  
Author(s):  
Natalia Purta ◽  
Taylor Miller-Ensminger ◽  
Adelina Voukadinova ◽  
Alan J. Wolfe ◽  
Catherine Putonti

Here, we introduce the 2.8-Mbp draft genome of Enterococcus faecalis strain UMB0843, isolated from the female urinary tract. E. faecalis is a leading cause of nosocomial infections, and many strains are often resistant to multiple antibiotics. We focus our genome analysis on the multiple genes involved in antibiotic resistance in this strain.


2019 ◽  
pp. 48-54
Author(s):  
Duy Binh Nguyen ◽  
Trung Tien Phan ◽  
Trong Hanh Hoang ◽  
Van Tuan Mai ◽  
Xuan Chuong Tran

Sepsis is a serious bacterial infection. The main treatment is using antibiotics. However, the rate of antibiotic resistance is very high and this resistance is related to the outcome of treatment. Objectives: To evaluate the situation of antibiotic resistance of some isolated bacteria in sepsis patients treated at Hue Central Hospital; to evaluate the relationship of antibiotic resistance to the treatment results in patients with sepsis. Subjects and methods: prospective study of 60 sepsis patients diagnosed according to the criteria of the 3rd International Consensus-Sepsis 3 and its susceptibility patterns from April 2017 to August 2018. Results and Conclusions: The current agents of sepsis are mainly S. suis, Burkhoderiae spp. and E. coli. E. coli is resistant to cephalosporins 3rd, 4th generation and quinolone group is over 75%; resistance to imipenem 11.1%; the ESBL rate is 60%. S. suis resistant to ampicilline 11.1%; no resistance has been recorded to ceftriaxone and vancomycine. Resistance of Burkholderiae spp. to cefepime and amoxicillin/clavulanic acid was 42.9% and 55.6%, resistant to imipenem and meropenem is 20%, resistance to ceftazidime was not recorded. The deaths were mostly dued to E. coli and K. pneumoniae. The mortality for patients infected with antibiotic-resistant bacteria are higher than for sensitive groups. Key words: Sepsis, bacterial infection, antibiotics


2020 ◽  
Vol 20 (2) ◽  
pp. 160-166
Author(s):  
Seyedeh Hanieh Eshaghi Zadeh ◽  
Hossein Fahimi ◽  
Fatemeh Fardsanei ◽  
Mohammad Mehdi Soltan Dallal

Background: Salmonellosis is a major food-borne disease worldwide. The increasing prevalence of antimicrobial resistance among food-borne pathogens such as Salmonella spp. is concerning. Objective: The main objective of this study is to identify class 1 integron genes and to determine antibiotic resistance patterns among Salmonella isolates from children with diarrhea. Methods: A total of 30 Salmonella isolates were recovered from children with diarrhea. The isolates were characterized for antimicrobial susceptibility and screened for the presence of class 1 integron genes (i.e. intI1, sulI1, and qacEΔ1). Results: The most prevalent serotype was Enteritidis 36.7%, followed by Paratyphi C (30%), and Typhimurium (16.7%). The highest rates of antibiotic resistance were obtained for nalidixic acid (53.3%), followed by streptomycin (40%), and tetracycline (36.7%). Regarding class 1 integrons, 36.7%, 26.7%, and 33.3% of the isolates carried intI1, SulI, and qacEΔ1, respectively, most of which (81.8%) were multidrug-resistant (MDR). Statistical analysis revealed that the presence of class 1 integron was significantly associated with resistance to streptomycin and tetracycline (p = 0.042). However, there was no association between class 1 integron and other antibiotics used in this study (p > 0.05). Conclusion: The high frequency of integron class 1 gene in MDR Salmonella strains indicates that these mobile genetic elements are versatile among different Salmonella serotypes, and associated with reduced susceptibility to many antimicrobials.


Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 874
Author(s):  
Periyasamy Sivalingam ◽  
John Poté ◽  
Kandasamy Prabakar

Over the past decades, the rising antibiotic resistance bacteria (ARB) are continuing to emerge as a global threat due to potential public health risk. Rapidly evolving antibiotic resistance and its persistence in the environment, have underpinned the need for more studies to identify the possible sources and limit the spread. In this context, not commonly studied and a neglected genetic material called extracellular DNA (eDNA) is gaining increased attention as it can be one of the significant drivers for transmission of extracellular ARGS (eARGs) via horizontal gene transfer (HGT) to competent environmental bacteria and diverse sources of antibiotic-resistance genes (ARGs) in the environment. Consequently, this review highlights the studies that address the environmental occurrence of eDNA and encoding eARGs and its impact on the environmental resistome. In this review, we also brief the recent dedicated technological advancements that are accelerating extraction of eDNA and the efficiency of treatment technologies in reducing eDNA that focuses on environmental antibiotic resistance and potential ecological health risk.


Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 775
Author(s):  
Kezia Drane ◽  
Roger Huerlimann ◽  
Michelle Power ◽  
Anna Whelan ◽  
Ellen Ariel ◽  
...  

Dissemination of antibiotic resistance (AR) in marine environments is a global concern with a propensity to affect public health and many ecosystems worldwide. We evaluated the use of sea turtles as sentinel species for monitoring AR in marine environments. In this field, antibiotic-resistant bacteria have been commonly identified by using standard culture and sensitivity tests, leading to an overrepresentation of specific, culturable bacterial classes in the available literature. AR was detected against all major antibiotic classes, but the highest cumulative global frequency of resistance in all represented geographical sites was against the beta-lactam class by a two-fold difference compared to all other antibiotics. Wastewater facilities and turtle rehabilitation centres were associated with higher incidences of multidrug-resistant bacteria (MDRB) accounting for an average of 58% and 49% of resistant isolates, respectively. Furthermore, a relatively similar prevalence of MDRB was seen in all studied locations. These data suggest that anthropogenically driven selection pressures for the development of AR in sea turtles and marine environments are relatively similar worldwide. There is a need, however, to establish direct demonstrable associations between AR in sea turtles in their respective marine environments with wastewater facilities and other anthropogenic activities worldwide.


Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 459
Author(s):  
Casey Stamereilers ◽  
Simon Wong ◽  
Philippos K. Tsourkas

The bacterium Paenibacillus larvae is the causative agent of American foulbrood, the most devastating bacterial disease of honeybees. Because P. larvae is antibiotic resistant, phages that infect it are currently used as alternative treatments. However, the acquisition by P. larvae of CRISPR spacer sequences from the phages could be an obstacle to treatment efforts. We searched nine complete genomes of P. larvae strains and identified 714 CRISPR spacer sequences, of which 384 are unique. Of the four epidemiologically important P. larvae strains, three of these have fewer than 20 spacers, while one strain has over 150 spacers. Of the 384 unique spacers, 18 are found as protospacers in the genomes of 49 currently sequenced P. larvae phages. One P. larvae strain does not have any protospacers found in phages, while another has eight. Protospacer distribution in the phages is uneven, with two phages having up to four protospacers, while a third of phages have none. Some phages lack protospacers found in closely related phages due to point mutations, indicating a possible escape mechanism. This study serve a point of reference for future studies on the CRISPR-Cas system in P. larvae as well as for comparative studies of other phage–host systems.


Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 575
Author(s):  
Emi Nishimura ◽  
Masateru Nishiyama ◽  
Kei Nukazawa ◽  
Yoshihiro Suzuki

Information on the actual existence of antibiotic-resistant bacteria in rivers where sewage, urban wastewater, and livestock wastewater do not load is essential to prevent the spread of antibiotic-resistant bacteria in water environments. This study compared the antibiotic resistance profile of Escherichia coli upstream and downstream of human habitation. The survey was conducted in the summer, winter, and spring seasons. Resistance to one or more antibiotics at upstream and downstream sites was on average 18% and 20%, respectively, and no significant difference was observed between the survey sites. The resistance rates at the upstream site (total of 98 isolated strains) to each antibiotic were cefazolin 17%, tetracycline 12%, and ampicillin 8%, in descending order. Conversely, for the downstream site (total of 89 isolated strains), the rates were ampicillin 16%, cefazolin 16%, and tetracycline 1% in descending order. The resistance rate of tetracycline in the downstream site was significantly lower than that of the upstream site. Furthermore, phylogenetic analysis revealed that many strains showed different resistance profiles even in the same cluster of the Pulsed-Field Gel Electrophoresis (PFGE) pattern. Moreover, the resistance profiles differed in the same cluster of the upstream and the downstream sites. In flowing from the upstream to the downstream site, it is plausible that E. coli transmitted or lacked the antibiotic resistance gene.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1841
Author(s):  
Thanaporn Chuen-Im ◽  
Korapan Sawetsuwannakun ◽  
Pimmnapar Neesanant ◽  
Nakarin Kitkumthorn

Antibiotic resistance of microorganisms is a serious health problem for both humans and animals. Infection of these bacteria may result in therapy failure, leading to high mortality rates. During an early intervention program process, the Sea Turtle Conservation Center of Thailand (STCCT) has faced high mortality rates due to bacterial infection. Previously, investigation of juvenile turtle carcasses found etiological agents in tissue lesions. Further determination of sea water in the turtle holding tanks revealed a prevalence of these causative agents in water samples, implying association of bacterial isolates in rearing water and infection in captive turtles. In this study, we examined the antibiotic resistance of bacteria in seawater from the turtle holding tank for a management plan of juvenile turtles with bacterial infection. The examination was carried out in three periods: 2015 to 2016, 2018, and 2019. The highest isolate numbers were resistant to beta-lactam, whilst low aminoglycoside resistance rates were observed. No gentamicin-resistant isolate was detected. Seventy-nine isolates (71.17%) were resistant to at least one antibiotic. Consideration of resistant bacterial and antibiotic numbers over three sampling periods indicated increased risk of antibiotic-resistant bacteria to sea turtle health. Essentially, this study emphasizes the importance of antibiotic-resistant bacterial assessment in rearing seawater for sea turtle husbandry.


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