scholarly journals Nutrient Scarcity in a New Defined Medium Reveals Metabolic Resistance to Antibiotics in the Fish Pathogen Piscirickettsia salmonis

2021 ◽  
Vol 12 ◽  
Author(s):  
Javiera Ortiz-Severín ◽  
Camila J. Stuardo ◽  
Natalia E. Jiménez ◽  
Ricardo Palma ◽  
María P. Cortés ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Antibiotic Susceptibility ◽  
Antibiotic Resistance Genes ◽  
Tca Cycle ◽  
Defined Medium ◽  
Pentose Phosphate ◽  
Nucleotide Metabolism ◽  
Penicillin G ◽  
Metabolic Resistance ◽  
Piscirickettsia Salmonis

Extensive use of antibiotics has been the primary treatment for the Salmonid Rickettsial Septicemia, a salmonid disease caused by the bacterium Piscirickettsia salmonis. Occurrence of antibiotic resistance has been explored in various P. salmonis isolates using different assays; however, P. salmonis is a nutritionally demanding intracellular facultative pathogen; thus, assessing its antibiotic susceptibility with standardized and validated protocols is essential. In this work, we studied the pathogen response to antibiotics using a genomic, a transcriptomic, and a phenotypic approach. A new defined medium (CMMAB) was developed based on a metabolic model of P. salmonis. CMMAB was formulated to increase bacterial growth in nutrient-limited conditions and to be suitable for performing antibiotic susceptibility tests. Antibiotic resistance was evaluated based on a comprehensive search of antibiotic resistance genes (ARGs) from P. salmonis genomes. Minimum inhibitory concentration assays were conducted to test the pathogen susceptibility to antibiotics from drug categories with predicted ARGs. In all tested P. salmonis strains, resistance to erythromycin, ampicillin, penicillin G, streptomycin, spectinomycin, polymyxin B, ceftazidime, and trimethoprim was medium-dependent, showing resistance to higher antibiotic concentrations in the CMMAB medium. The mechanism for antibiotic resistance to ampicillin in the defined medium was further explored and was proven to be associated to a decrease in the bacterial central metabolism, including the TCA cycle, the pentose-phosphate pathway, energy production, and nucleotide metabolism, and it was not associated with decreased growth rate of the bacterium or with the expression of any predicted ARG. Our results suggest that nutrient scarcity plays a role in the bacterial antibiotic resistance, protecting against the detrimental effects of antibiotics, and thus, we propose that P. salmonis exhibits a metabolic resistance to ampicillin when growing in a nutrient-limited medium.

scholarly journals Nitric oxide (NO) elicits aminoglycoside tolerance in Escherichia coli but antibiotic resistance gene carriage and NO sensitivity have not co-evolved

2021 ◽  
Author(s):  
Cláudia A. Ribeiro ◽  
Luke A. Rahman ◽  
Louis G. Holmes ◽  
Ayrianna M. Woody ◽  
Calum M. Webster ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Antibiotic Resistance ◽  
Antibiotic Susceptibility ◽  
Bacterial Pathogens ◽  
Antibiotic Resistance Gene ◽  
Antibiotic Resistance Genes ◽  
Resistance Mechanisms ◽  
Current Work ◽  
E Coli ◽  
Respiratory Inhibitor

AbstractThe spread of multidrug-resistance in Gram-negative bacterial pathogens presents a major clinical challenge, and new approaches are required to combat these organisms. Nitric oxide (NO) is a well-known antimicrobial that is produced by the immune system in response to infection, and numerous studies have demonstrated that NO is a respiratory inhibitor with both bacteriostatic and bactericidal properties. However, given that loss of aerobic respiratory complexes is known to diminish antibiotic efficacy, it was hypothesised that the potent respiratory inhibitor NO would elicit similar effects. Indeed, the current work demonstrates that pre-exposure to NO-releasers elicits a > tenfold increase in IC50 for gentamicin against pathogenic E. coli (i.e. a huge decrease in lethality). It was therefore hypothesised that hyper-sensitivity to NO may have arisen in bacterial pathogens and that this trait could promote the acquisition of antibiotic-resistance mechanisms through enabling cells to persist in the presence of toxic levels of antibiotic. To test this hypothesis, genomics and microbiological approaches were used to screen a collection of E. coli clinical isolates for antibiotic susceptibility and NO tolerance, although the data did not support a correlation between increased carriage of antibiotic resistance genes and NO tolerance. However, the current work has important implications for how antibiotic susceptibility might be measured in future (i.e. ± NO) and underlines the evolutionary advantage for bacterial pathogens to maintain tolerance to toxic levels of NO.

scholarly journals Preliminary Results on the Prevalence of Salmonella Spp. in Marine Animals Stranded in Sicilian Coasts: Antibiotic Susceptibility Profile and ARGs Detection in the Isolated Strains

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 930
Author(s):  
Delia Gambino ◽  
Sonia Sciortino ◽  
Sergio Migliore ◽  
Lucia Galuppo ◽  
Roberto Puleio ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Antibiotic Susceptibility ◽  
Antibiotic Resistance Genes ◽  
Diffusion Method ◽  
Salmonella Spp ◽  
Marine Animals ◽  
Disk Diffusion Method ◽  
Phenotypic Resistance ◽  
Low Prevalence

The presence of Salmonella spp. in marine animals is a consequence of contamination from terrestrial sources (human activities and animals). Bacteria present in marine environments, including Salmonella spp., can be antibiotic resistant or harbor resistance genes. In this study, Salmonella spp. detection was performed on 176 marine animals stranded in the Sicilian coasts (south Italy). Antibiotic susceptibility, by disk diffusion method and MIC determination, and antibiotic resistance genes, by molecular methods (PCR) of the Salmonella spp. strains, were evaluated. We isolated Salmonella spp. in three animals, though no pathological signs were detected. Our results showed a low prevalence of Salmonella spp. (1.7%) and a low incidence of phenotypic resistance in three Salmonella spp. strains isolated. Indeed, of the three strains, only Salmonella subsp. enterica serovar Typhimurium from S. coeruleoalba and M. mobular showed phenotypic resistance: the first to ampicillin, tetracycline, and sulphamethoxazole, while the latter only to sulphamethoxazole. However, all strains harbored resistance genes (blaTEM, blaOXA, tet(A), tet(D), tet(E), sulI, and sulII). Although the low prevalence of Salmonella spp. found in this study does not represent a relevant health issue, our data contribute to the collection of information on the spread of ARGs, elements involved in antibiotic resistance, now considered a zoonosis in a One Health approach.

Prevalence, Antibiogram, and cdt Genes of Toxigenic Campylobacter jejuni in Salad Style Vegetables (Ulam) at Farms and Retail Outlets in Terengganu

2015 ◽  
Vol 78 (1) ◽  
pp. 65-71 ◽  
Author(s):  
MOHD IKHSAN KHALID ◽  
JOHN YEW HUAT TANG ◽  
NABILA HUDA BAHARUDDIN ◽  
NASIHA SHAKINA RAHMAN ◽  
NURUL FAIZZAH RAHIMI ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Multiplex Pcr ◽  
Campylobacter Jejuni ◽  
Antibiotic Susceptibility ◽  
Penicillin G ◽  
Diffusion Method ◽  
Cytolethal Distending Toxin ◽  
Disk Diffusion Method ◽  
Retail Outlets ◽  
Pcr Method

The present study was conducted to investigate the prevalence and antibiotic resistance among Campylobacter jejuni in ulam at farms and retail outlets located in Kuala Terengganu, Malaysia. A total of 526 samples (ulam, soil, and fertilizer) were investigated for the presence of C. jejuni and the gene for cytolethal distending toxin (cdt) by using a multiplex PCR method. Antibiotic susceptibility to 10 types of antibiotics was determined using the disk diffusion method for 33 C. jejuni isolates. The average prevalence of contaminated samples from farms, wet markets, and supermarkets was 35.29, 52.66, and 69.88%, respectively. The cdt gene was not detected in 24 of the 33 C. jejuni isolates, but 9 isolates harbored cdtC. Antibiotic resistance in C. jejuni isolates was highest to penicillin G (96.97% of isolates) followed by vancomycin (87.88%), ampicillin (75.76%), erythromycin (60.61%), tetracycline (9.09%), amikacin (6.06%), and norfloxacin (3.03%); none of the isolates were resistant to ciprofloxacin, enrofloxacin, and gentamicin. In this study, C. jejuni was present in ulam, and some isolates were highly resistant to some antibiotics but not to quinolones. Thus, appropriate attention and measures are required to prevent C. jejuni contamination on farms and at retail outlets.

scholarly journals Decreased Antibiotic Susceptibility in Pseudomonas aeruginosa Surviving UV Irradition

2021 ◽  
Vol 12 ◽  
Author(s):  
Hai-bei Li ◽  
Ai-ming Hou ◽  
Tian-jiao Chen ◽  
Dong Yang ◽  
Zheng-shan Chen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Uv Irradiation ◽  
Antibiotic Susceptibility ◽  
Antibiotic Resistance Genes ◽  
Polymyxin B ◽  
Uv Exposure ◽  
Uv Disinfection ◽  
Excellent Performance

Given its excellent performance against the pathogens, UV disinfection has been applied broadly in different fields. However, only limited studies have comprehensively investigated the response of bacteria surviving UV irradiation to the environmental antibiotic stress. Here, we investigated the antibiotic susceptibility of Pseudomonas aeruginosa suffering from the UV irradiation. Our results revealed that UV exposure may decrease the susceptibility to tetracycline, ciprofloxacin, and polymyxin B in the survival P. aeruginosa. Mechanistically, UV exposure causes oxidative stress in P. aeruginosa and consequently induces dysregulation of genes contributed to the related antibiotic resistance genes. These results revealed that the insufficient ultraviolet radiation dose may result in the decreased antibiotic susceptibility in the pathogens, thus posing potential threats to the environment and human health.

Antibiotic susceptibility profiles and frequency of resistance genes in clinical Shiga toxin-producing Escherichia coli isolates from Michigan over a 14-year period

2021 ◽  
Author(s):  
Sanjana Mukherjee ◽  
Heather M. Blankenship ◽  
Jose A. Rodrigues ◽  
Rebekah E. Mosci ◽  
James T. Rudrik ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Shiga Toxin ◽  
Antibiotic Susceptibility ◽  
Genetic Relatedness ◽  
Antibiotic Resistance Genes ◽  
Genomic Analysis ◽  
Mechanisms Of Resistance ◽  
Susceptibility Profiles

Background: Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen that contributes to over 250,000 infections in the US each year. Because antibiotics are not recommended for STEC infections, resistance in STEC has not been widely researched despite an increased likelihood for the transfer of resistance gene from STEC to opportunistic pathogens residing within the same microbial community. Methods: Between 2001 and 2014, 969 STEC isolates were collected from Michigan patients. Serotyping and antibiotic susceptibility profiles to clinically relevant antibiotics were determined using disc diffusion, while epidemiological data was used to identify factors associated with resistance. Whole genome sequencing was used to examine genetic relatedness and identify genetic determinants and mechanisms of resistance in the non-O157 isolates. Results: Increasing frequencies of resistance to at least one antibiotic was observed over the 14 years (p=0.01). While the non-O157 serogroups were more commonly resistant than O157 (Odds Ratio: 2.4; 95% Confidence Interval:1.43-4.05), the frequency of ampicillin resistance among O157 isolates was significantly higher in Michigan compared to the national average (p=0.03). Genomic analysis of 321 non-O157 isolates uncovered 32 distinct antibiotic resistance genes (ARGs). Although mutations in genes encoding resistance to ciprofloxacin and ampicillin were detected in four isolates, most of the horizontally acquired ARGs conferred resistance to aminoglycosides, β-lactams, sulfonamides and/or tetracycline. Conclusions: This study provides insight into the mechanisms of resistance in a large collection of clinical non-O157 STEC isolates and demonstrates that antibiotic resistance among all STEC serogroups has increased over time, prompting the need for enhanced surveillance.

Investigation of the antibiotic resistance and biofilm formation of Staphylococcus aureus strains isolated from gangrenous mastitis of ewes

2012 ◽  
Vol 60 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Osman Tel ◽  
Özkan Aslantaş ◽  
Oktay Keskin ◽  
Ebru Yilmaz ◽  
Cemil Demir
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Virulence Factor ◽  
Resistance Genes ◽  
Biofilm Formation ◽  
Antibiotic Resistance Genes ◽  
Penicillin G ◽  
Beta Lactamase ◽  
Potential Virulence Factor ◽  
Amoxicillin Clavulanic Acid

In this study,Staphylococcus aureusstrains (n = 110) isolated from seven ewe flocks in Sanliurfa, Turkey were screened for antibiotic resistance and biofilmforming ability as well as for genes associated with antibiotic resistance and biofilm-forming ability. All isolates were found to be susceptible to oxacillin, gentamicin, clindamycin, cefoxitin, tetracycline, vancomycin, amoxicillin-clavulanic acid, ciprofloxacin and sulphamethoxazole-trimethoprim. The percent proportions of strains resistant to penicillin G, ampicillin and erythromycin were 27.2% (n = 30), 25.4% (n = 28) and 6.3% (n = 7), respectively. Regarding the antibiotic resistance genes, 32 (29%) isolates carried theblaZ and 8 (7.2%) theermC gene. Other resistance genes were not detected in the isolates. All isolates showed biofilm-forming ability on Congo red agar (CRA), while 108 (98.18%) and 101 (91.81%) of them were identified as biofilm producers by the use of standard tube (ST) and microplate (MP) methods, respectively. All isolates carried theicaA andicaD genes but none of them harboured thebapgene. The results demonstrated thatS. aureusisolates from gangrenous mastitis were mainly resistant to penicillins (which are susceptible to the staphylococcal beta-lactamase enzyme), and less frequently to erythromycin. Furthermore, all of theS. aureusisolates produced biofilm which was considered a potential virulence factor in the pathogenesis of staphylococcal mastitis.

scholarly journals Analysis of virulence factors and antibiotic resistance genes in Group B Streptococcus from clinical samples

2020 ◽  
Author(s):  
Raymond Mudzana ◽  
Rooyen T Mavenyengwa ◽  
Muchaneta Gudza-Mugabe
Keyword(s):  
Antibiotic Resistance ◽  
Pregnant Women ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Antibiotic Resistance Genes ◽  
Penicillin G ◽  
Multi Drug Resistance ◽  
Clinical Samples ◽  
Group B

Abstract Background: Streptococcus agalacticae (Group B Streptococcus, GBS) is one of the most important causative agents of serious infections among neonates. This study was carried out to identify antibiotic resistance and virulence genes associated with GBS isolated from pregnant women.Methods: A total of 43 GBS isolates were obtained from 420 vaginal samples collected from HIV positive and negative women who were 13-35 weeks pregnant attending Antenatal Care at Chitungwiza and Harare Central Hospitals in Zimbabwe. Identification tests of GBS isolates was done using standard bacteriological methods and molecular identification testing. Antibiotic susceptibility testing was done using the modified Kirby-Bauer method and E-test strips. The boiling method was used to extract DNA and Polymerase Chain Reaction (PCR) was used to screen for 13 genes. Data was fed into SPSS 24.0.Results: Nine distinct virulence gene profiles were identified and hly-scpB-bca-rib 37.2% (16/43) was common. The virulence genes identified were namely hly 97.8% (42/43), scpB 90.1% (39/43), bca 86.0% (37/43), rib 69.8% (30/43) and bac 11.6% (5/43). High resistance to tetracycline 97.7% (42/43) was reported followed by 72.1% (31/43) cefazolin, 69.8% (30/43) penicillin G, 58.1% (25/43) ampicillin, 55.8% (24/43) clindamycin, 46.5% (20/43) ceftriaxone, 34.9% (15/43) chloramphenicol, and 30.2% (13/43) for both erythromycin and vancomycin using disk diffusion. Antibiotic resistance genes among the resistant and intermediate-resistant isolates showed high frequencies for tetM 97.6% (41/42) and low frequencies for ermB 34.5% (10/29), ermTR 10.3% (3/29), mefA 3.4% (1/29), tetO 2.4% (1/42) and linB 0% (0/35). The atr housekeeping gene yielded 100% (43/43) positive results, whilst the mobile genetic element IS1548 yielded 9.3% (4/43).Conclusion: The study showed high prevalence of hly, scpB, bca and rib virulence genes in S. agalactiae strains isolated from pregnant women. Tetracycline resistance was predominantly caused by the tetM gene, whilst macrolide resistance was predominantly due to the presence of erm methylase, with the ermB gene being more prevalent. Multi-drug resistance coupled with the recovery of resistant isolates to antimicrobial agents such as penicillins indicates the importance of GBS surveillance and susceptibility tests. It was also observed that in vitro phenotypic resistance is not always accurately predicted by resistance genotypes.

scholarly journals Antibiotic Resistance Pattern of Bacteroides Fragilis Isolated From Clinical and Gastrointestinal Specimens

2021 ◽  
Author(s):  
Seyedesomaye Jasemi ◽  
Mohammad Emaneini ◽  
Zahra Ahmadinejad ◽  
Mohammad Sadegh Fazeli ◽  
Leonardo A. Sechi ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Bacteroides Fragilis ◽  
Antibiotic Resistance Genes ◽  
Penicillin G ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Gi Tract ◽  
Antibiotic Resistance Pattern

Abstract Background: Bacteroides fragilis is a part of the normal gastrointestinal flora and the most prevalent anaerobic bacteria causes’ infection. It is highly resistant to antibiotics and contains abundant antibiotic resistance mechanisms. Methods: The antibiotic resistance pattern of 78 isolates of B. fragilis (56 strains from the gastrointestinal [GI] tract and 22 strains from clinical samples) was investigated using agar dilution method. The gene encoding Bacteroides fargilis toxin bft, and antibiotic resistance genes were targeted by PCR assay. Results: The highest rate of resistance was observed for penicillin G (100%) followed by tetracycline (74.4%), clindamycin (41%) and cefoxitin (38.5%). Only a single isolate showed resistance to imipenem which contained cfiA and IS1186 genes. All isolates were susceptible to metronidazole. Accordingly, tetQ (87.2%), cepA (73.1%) and ermF (64.1%) were the most abundant antibiotic-resistant genes identified in this study. MIC values for penicillin, cefoxitin and clindamycin were significantly different among isolates with the cepA, cfxA and ermF in compare with those lacking such genes. In addition, 22.7% and 17.8% of clinical and GI tract isolates had the bft gene, respectively. Conclusions: Therefore, it is of utmost importance to determine the antibiotic resistance patterns of B. fragilis periodically in different geographical areas to provide a suitable treatment profile for patients and to prevent improper antibiotic prescriptions.

scholarly journals Characteristics of antibiotics and antibiotic resistance genes in Qingcaosha Reservoir in Yangtze River Delta, China

2020 ◽  
Author(s):  
Ting Xu ◽  
Wanting Zhao ◽  
Xueping Guo ◽  
Hongchang Zhang ◽  
Shuangqing Hu ◽  
...  
Keyword(s):  
Drinking Water ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Yangtze River ◽  
Water Reservoir ◽  
Antibiotic Resistance Genes ◽  
Yangtze River Delta ◽  
River Delta ◽  
Penicillin G ◽  
Drinking Water Reservoir

Abstract Background Aquatic ecosystems are considered to be among the most important reservoirs of antibiotic resistance genes (ARGs). Drinking water sources were usually parts of lakes and rivers in Yangtze River Delta, among which Qingcaosha Reservoir is the largest river impoundment and benefit the population of more than 13 million for Shanghai city. In this study, we aimed at investigating the distribution of antibiotics and ARGs to characterize the pollution across various sites in Qingcaosha Reservoir in three seasons. Results Sulfamethoxazole, sulfamonomethoxine and penicillin G potassium salt were the dominant antibiotics and of high detection frequencies in this reservoir. Sulfonamide resistance genes ( sul1 and sul2 ) were the most prevalent and predominant genes. Higher total relative abundance of the ARGs were detected in the site closest to the inflow than those in other sites. Overall, the concentrations of antibiotics in May (spring) were relatively lower than November (autumn) and February (winter). Correlation analysis indicated sul1 , ermB and mphA had positive correlation with corresponding antibiotics in February and intI1 was also greatly positively correlated to sul1 , sul2 , ermB and mphA . Conclusion In conclusion, the antibiotics and ARGs were widespread in Qingcaosha Reservoir. Our result indicated that the drinking water reservoir might serve as gene reservoir for antibiotic resistance and mobile gene element intI1 can serve as a medium to contribute to the widespread of various ARGs. What is more, we considered that Reservoir could be served as a functional area contributing to the elimination of ARGs.

scholarly journals Trend in Antibiotic Resistance of Streptococcus Pneumoniae and Haemophilus Influenzae Strains Isolated from Community Acquired Respiratory Tract Infections in Dakar, Senegal between 2005 and 2008

2010 ◽  
Vol 3 ◽  
pp. MBI.S3819
Author(s):  
A. Guèye Ndiaye ◽  
Hounkponou Edwige ◽  
Fatou Bintou Guèye ◽  
Cheikh Saad Bouh Boye
Keyword(s):  
Antibiotic Resistance ◽  
Streptococcus Pneumoniae ◽  
Respiratory Tract ◽  
Haemophilus Influenzae ◽  
Antibiotic Susceptibility ◽  
Respiratory Tract Infections ◽  
Penicillin G ◽  
Respiratory Pathogens ◽  
Resistance Patterns ◽  
Tract Infections

Development of antibiotic resistance among common respiratory pathogens is a major cause of concern worldwide. Streptococcus pneumoniae and Haemophilus influenzae are among the most common respiratory pathogens. In this study, representative samples obtained from 3 different medical centers in Dakar, Senegal were subjected to antibiotic susceptibility testing. The samples were collected from 2005 to 2008 and the data obtained was compared to establish resistance patterns between the two years (i.e. 2005–2006 to 2007–2008). S. pneumoniae exhibited a significant increase in the resistance to azithromycin and the intermediate susceptibility to penicillin G and cotrimoxazole. H. influenzae also exhibited a significant increase in resistance to azithromycin and intermediate susceptibility to chloramphenicol. None of H. influenzae samples were resistant to amoxicillin/clavulanic acid, cephalosporin and fluroquinolones and most of the S. pneumoniae isolates demonstrated high susceptibility to the antibiotics tested. Results from this study will provide greater insights to antibiotic therapy during respiratory tract infections in Dakar, Senegal. This study also establishes the importance of continuous monitoring of antibiotic susceptibility patterns that are often region-specific.

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