scholarly journals Characteristics of ciprofloxacin-resistant Enterobacteriaceae isolates recovered from wastewater of an Algerian hospital

2016 ◽  
Vol 10 (07) ◽  
pp. 728-734 ◽  
Author(s):  
Lynda Anssour ◽  
Yamina Messai ◽  
Vanesa Estepa ◽  
Carmen Torres ◽  
Rabah Bakour
Keyword(s):  
Resistance Genes ◽  
Klebsiella Oxytoca ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Phylogenetic Groups ◽  
Disk Diffusion Method ◽  
Hospital Effluents ◽  
Sequence Types

Introduction: Hospital effluents are a source of environmental pollution by drugs, antibiotic-resistant bacteria, and resistance genes. Quinolones, particularly ciprofloxacin, are commonly detected in these effluents, contributing to the emergence of antimicrobial resistance. The objective of this study was to characterize ciprofloxacin-resistant Enterobacteriaceae in hospital effluents. Methodology: Isolates were selected on Tergitol-7 agar supplemented with ciprofloxacin and genotyped by ERIC-PCR. Antibiotic susceptibility testing was done using the disk diffusion method, and minimum inhibitory concentrations were determined using the agar dilution method. Resistance genes, integrons, phylogenetic groups, and sequence types were identified by PCR and sequencing. Results: A total of 17 ciprofloxacin-resistant isolates were characterized: Escherichia coli, Escherichia vulneris, Klebsiella pneumoniae, Klebsiella oxytoca, Citrobacter freundii, and Citrobacter koseri/farmeri. Isolates presented concomitant resistance to nalidixic acid, ciprofloxacin, ofloxacin, and pefloxacin. A diversity in mutation patterns in gyrA and parC genes and new amino-acid substitutions in GyrA subunit were observed. Quinolone plasmidic resistance genes qnrB1, qnrB2, qnrB5/19, qnrS1, and aac(6’)-Ib-cr were detected. Resistance to other antibiotic classes was observed. Class 1 integrons and resistance genes blaCTX-M-15, blaOXA-1, sul1, sul2, sul3, tetA, tetB, aadA1/2, aadA5, aph(3’)-Ia, aac(3)II, dfrA1, dfrA5, dfrA7, and dfrA12 were detected. Bacterial tolerance to cadmium, zinc, and mercury was observed with the presence of the merA gene. E. coli isolates belonged to phylogenetic groups A, B1, and D and to sequence types ST405, ST443, ST101, ST10, and ST347. Conclusions: This study highlighted bacterial multidrug resistance linked to ciprofloxacin and, consequently, the risk of bacterial exposure to this antibiotic.

scholarly journals Characterization of plasmid-mediated qnrA and qnrB genes among Enterobacteriaceae strains: quinolone resistance and ESBL production in Ismailia, Egypt

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Samaa A. Taha ◽  
Hanan Hassan Omar ◽  
wafaa Hassan Hassan
Keyword(s):  
Resistance Genes ◽  
Quinolone Resistance ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
University Hospitals ◽  
Disk Diffusion Method ◽  
Extended Spectrum Beta Lactamase ◽  
Tract Infections ◽  
Resistance Rates

Abstract Background Plasmid-mediated quinolone resistance genes (PMQR) are mainly associated with clinical isolates of Enterobacteriaceae and complicate treatment of infections caused by these isolates worldwide. Extended-spectrum-beta-lactamase (ESBL)-producing bacteria are resistant to common antibiotics and also through many mechanisms, ESBL could be disabling other types of antibiotics. This study aimed to assess the prevalence of quinolone resistance and ESBL among Enterobacteriaceae strains and investigated the presence of qnrA and qnrB genes in these strains which were isolated from urinary tract infections in Ismailia, Egypt. Ninety-four Enterobacteriaceae isolates were collected from cases of UTIs admitted to the intensive care unit, Suez-Canal University Hospitals, between October 2017 and January 2018. Antibacterial susceptibility was determined by the disk diffusion method. A polymerase chain reaction assay was used to detect qnrA and qnrB resistance genes in quinolone- and fluoroquinolone-resistant and ESBL strains. Also, ciprofloxacin MIC was determined by the agar dilution method. Results Resistance rates were 59.6%, 54.3%, 53.2%, 53.2%, and 53.2% to NA, LEV, NOR, CIP, and FX, respectively. Of 56 NA-resistant isolates, 7 (12.5%) and 6 (10.7%) were positive for qnrA and qnrB, respectively, with only one isolate co-harboring both genes. ESBL-producing bacteria was 66.2% of isolates. The MICs for ciprofloxacin ranged from 32–256 μg/ml in ciprofloxacin-resistant isolates. Conclusion Our study shows high resistance rates of Enterobacteriaceae to quinolones and ESBL in our hospital which necessitate appropriate use of these antibiotics to reserve their application for therapy. The prevalence of quinolone-resistant and ESBL-producing Enterobacteriaceae was approximately 60% and 70% respectively.

scholarly journals Comparison of methods for the determination of antimicrobial resistance in Campylobacter spp. human and the food chain isolates

2008 ◽  
Vol 52 (No. 4) ◽  
pp. 169-174
Author(s):  
M. Holasova ◽  
R. Karpiskova ◽  
S. Karpiskova ◽  
V. Babak ◽  
J. Schlegelova
Keyword(s):  
Nalidixic Acid ◽  
Antimicrobial Agents ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Study Results ◽  
Agar Dilution

With a microdilution method, using the commercial diagnostic test Sensititre Susceptibility Plates for Campylobacter MIC (Trek Diagnostic Systems, Cleveland, OH, USA), disk diffusion and agar dilution method, resistance to six antimicrobial agents were examined in a reference strain <i>Campylobacter jejuni</i> ATCC 33560 and 73 thermo-tolerant isolates of <i>Campylobacter</i> spp. For the microdilution method and all tested antimicrobial agents, our determined values of microbiological breakpoints of resistant strains were suggested as the minimum inhibitory concentration (MIC<sub>R</sub>) for ciprofloxacin &ge; 0.5, erythromycin &ge; 4, gentamicin &ge; 4, nalidixic acid &ge; 32 and tetracycline &ge; 4 &mu;g/ml. On the basis of our study results, strains resistant to clindamycin were MIC<sub>R</sub> &ge; 2 &mu;g/ml for the dilution methods and a zone diameter R ≤ 16 mm for the disk diffusion method. Comparison of the results of the resistance examination, a microdilution method and disk diffusion method with the reference agar dilution method, showed that all compared methods yielded identical results with the exception of the resistance determination in erythromycin and nalidixic acid. The errors were mostly the result of the interpretation criteria for MIC<sub>R</sub> of agar dilution method and different conditions of cultivation used. However, the compared methods, provide results comparable with the reference method having greater convenience of measurement.

scholarly journals Inaccuracy of the Disk Diffusion Method Compared with the Agar Dilution Method for Susceptibility Testing of Campylobacter spp.

2011 ◽  
Vol 50 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Mirva Lehtopolku ◽  
Pirkko Kotilainen ◽  
Pauli Puukka ◽  
Ulla-Maija Nakari ◽  
Anja Siitonen ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Agar Dilution ◽  
Campylobacter Spp

scholarly journals In vitro efficacy of synergistic antibiotic combinations in imipenem resistant Pseudomonas aeruginosa strains

2017 ◽  
Vol 9 (1) ◽  
pp. 3-8
Author(s):  
Aleya Farzana ◽  
S. M. Shamsuzzaman
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Considerable Proportion ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
New Antibiotics

The increase in antibiotic resistance coincided with the decline in production of new antibiotics. Combination antibiotic treatment is preferred in nosocomial infections caused by multidrug resistant Pseudomonas aeruginosa. In vitro synergism test by agar dilution method were used to choose the combinations which might be used in clinic. The aim of this study was to investigate the synergistic efficacy of antibiotic combinations in imipenem resistant P. aeruginosa strains. Carbapenem resistance (imipenem and meropenem) wasdetermined by disk diffusion method. Among isolated P. aeruginosa 44.9% were cabapenem resistant. The MIC of drugs among 25 imipenem resistant isolates ranged from >_ 256 mg/L to <_ 8 mg/L for imipenem, >_ 1024 mg/L to <_ 64 mg/L for ceftriaxone, >_ 256 mg/L to <_ 8 mg/L for amikacin, >_ 16 mg/L to <_ 2 mg/L for colistin, >_ 512 mg/L to <_ 16 mg/L for piperacillin/tazobactam. Among antibiotic combinations, piperacillin /tazobactam- amikacin was most effective with 80% synergism next to which was imipenem-amikacin with 60% synergism, then imipenem-colistin with 50% synergism, imipenem-ceftriaxone with 30% synergism. Only one combination (piperacillin/tazobactum -imipenem showed 20% antagonism. All these combinations had considerable proportion of additive effect which is also desirable for these multi drug resistant isolates.Bangladesh J Med Microbiol 2015; 9 (1): 3-8

scholarly journals Functional Nanostructured Oligochitosan–Silica/ Carboxymethyl Cellulose Hybrid Materials: Synthesis and Investigation of Their Antifungal Abilities

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 628 ◽  
Author(s):  
Thuy N Nguyen ◽  
Thu NM Huynh ◽  
DongQuy Hoang ◽  
Dai Hai Nguyen ◽  
Quoc Hien Nguyen ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Hybrid Materials ◽  
Carboxymethyl Cellulose ◽  
Synergistic Effects ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Waste Products ◽  
Chemical Structures

Functional hybrid materials were successfully synthesized from low-cost waste products, such as oligochitosan (OCS) obtained from chitosan (one of the main components in crab shells) and nanosilica (nSiO2) obtained from rice husk, in a 1:1 ratio (w/w), and their dispersion in the presence of carboxymethyl cellulose at pH 7 was stable for over one month without aggregation. The molecular weights, chemical structures, morphologies, and crystallinities of the obtained materials were characterized by GPC, FTIR, TEM, and XRD, respectively. The antifungal effects of OCS, nSiO2, and the OCS/nSiO2 hybrid materials were investigated via a disk-diffusion method. The results showed that the nanohybrid materials had better resistance to Phytophthora infestans fungus than the individual components, and a concentration of the OCS2/nSiO2 hybrid material of 800 mg L−1 was the lowest concentration where the material completely inhibited Phytophthora infestans growth, as measured via an agar dilution method. This study not only creates a novel environmentally friendly material with unique synergistic effects that can replace current toxic agrochemicals but also can be considered a new platform for further research in green agricultural applications.

scholarly journals Detection of Plasmid-Mediated Colistin Resistant mcr-1 Gene in Escherichia coli Isolated from Infected Chicken Livers in Nepal

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2060
Author(s):  
Sayara Bista ◽  
Upendra Thapa Shrestha ◽  
Binod Dhungel ◽  
Pragya Koirala ◽  
Tulsi Ram Gompo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Conventional Polymerase Chain Reaction ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Human Pathogens ◽  
Colistin Resistance ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Agar Dilution

Background: Plasmid-mediated resistance to the colistin in poultry is considered as an emerging problem worldwide. While poultry constitutes the major industry in Nepal, there is a paucity of evidence on colistin resistance in Escherichia coli isolates causing natural infections in poultry. This study aimed to explore the prevalence of plasmid-mediated colistin resistance gene, mcr-1 in E. coli isolated from liver samples of dead poultry suspected of E. coli infections. Methods: A total of two hundred and seventy liver samples (227 broilers and 43 layers) from dead poultry suspected of colibacillosis were collected from post-mortem in the Central Veterinary Laboratory (CVL), Kathmandu, between 1 February and 31 July 2019. The specimens were processed to isolate and identify E. coli; an antimicrobial susceptibility test (AST) using disk diffusion method was performed with 12 different antibiotics: Amikacin (30 µg), ampicillin (10 µg), ciprofloxacin (5 µg), chloramphenicol (30 µg), cefoxitin (30 µg), ceftazidime (30 µg), ceftriaxone (30 µg), cotrimoxazole (25 µg), gentamicin (10 µg), imipenem (10 µg), levofloxacin (5 µg) and tetracycline (30 µg). Colistin resistance was determined by agar dilution method and colistin-resistant strains were further screened for plasmid-mediated mcr-1 gene, using conventional polymerase chain reaction (PCR). Results: Out of 270 liver samples, 53.3% (144/270) showed growth of E. coli. The highest number (54%; 109/202) of E. coli isolates was obtained in the liver samples from poultry birds (of both types) aged less than forty days. In AST, 95.1% (137/144) and 82.6% (119/144) of E. coli isolates were resistant against tetracycline and ciprofloxacin, respectively, while 13.2% (19/144) and 25.7% (37/144) isolates were resistant to cefoxitin and imipenem, respectively. In the same assay, 76.4% (110/144) E. coli isolates were multi-drug resistant (MDR). The phenotypic prevalence of colistin resistance was 28.5% (41/144). In the PCR assay, 43.9% (18/41) of colistin-resistant isolates were screened positive for plasmid-mediated mcr-1. Conclusion: The high prevalence of mcr-1 in colistin-resistant E. coli isolates in our study is a cause of concern for the probable coming emergence of colistin resistance in human pathogens, due to horizontal transfer of resistant genes from poultry to human isolates.

Biocide's susceptibility and frequency of biocide resistance genes and the effect of exposure to sub-inhibitory concentrations of sodium hypochlorite on antibiotic susceptibility of Stenotrophomonas maltophilia

2021 ◽  
Author(s):  
Safar Ali Alizadeh ◽  
Amir Javadi ◽  
Farhad Nikkhahi ◽  
Mohammad Rostamani ◽  
Mehdi Bakht ◽  
...  
Keyword(s):  
Sodium Hypochlorite ◽  
Resistance Genes ◽  
Antibiotic Susceptibility ◽  
Inhibitory Concentration ◽  
Microtiter Plate ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Dilution Method ◽  
Disk Diffusion Method ◽  
Microtiter Plate Assay

Background: The overused of biocides in healthcare-facilities poses risk for emergence and spread of antibiotic resistance among nosocomial pathogens. Hospital-acquired infections due to S. maltophilia particularly in the immunocompromised patients have been increased. The objective of this study was to evaluate the susceptibility of S. maltophilia clinical isolates to commonly used biocides in hospitals, as well the frequency of biocides resistance gene among them. This study also intended to assess the effect of exposure of S. maltophilia isolates to sub-inhibitory concentrations of sodium hypochlorite upon the antimicrobial susceptibility patterns. Methods: This study included 97 S. maltophilia isolates. Biofilm formation was determined by microtiter plate assay. The susceptibility tests of five biocides were studied against all S. maltophilia isolates by microbroth dilution method. Susceptibility of isolates to antibiotics by disk diffusion method were compared before and after exposure to sub-inhibitory concentrations of sodium hypochlorite. Presence of qacE, qacEΔ1, SugE genes was screened by PCR. Results: Based on minimum inhibitory and bactericidal concentrations of biocides sodium hypochlorite 5% and ethyl alcohol 70% were the strongest and weakest against S. maltophilia isolates, respectively. The frequency of sugE gene resistance genes was found to be high (90.7%) in our clinical S. maltophilia isolates. None of the isolates carried qacE and qacEΔ1 gene. Exposure to sub-inhibitory concentration of sodium hypochlorite showed significantly change the susceptibility of isolates towards ceftazidime (P = .019), ticarcillin/clavulanate (P = .009). and chloramphenicol (P = .028). Conclusions: This study demonstrated that exposure to sub-inhibitory concentration of sodium hypochlorite leads to reduced antibiotic susceptibility and development of multidrug-resistant S. maltophilia strains.

scholarly journals Department of Microbiology, Bangladesh Agricultural University, Mymensingh

2016 ◽  
Vol 2 (2) ◽  
pp. 3-6
Author(s):  
Nahida Akther Zahan ◽  
Md. Akram Hossain ◽  
AKM Shamsuzzaman ◽  
AKM Musa ◽  
Md. Chand Mahamud ◽  
...  
Keyword(s):  
Clinical Laboratory ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Toxin Production ◽  
Latex Agglutination ◽  
Diffusion Method ◽  
National Committee ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method

The study was done to detect different exotoxins among the strains of Staphylococcus aureus isolated in the department of Microbiology, Mymensingh Medical College in collaboration with the Department of Medicine under the Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh between the periods from July, 2006 to June, 2007. A total of 40 S. aureus isolates investigated in this study were identified by standard microbiological techniques. Antimicrobial susceptibility of the isolates to Oxacillin was carried out by disk diffusion method as per recommendation of the National Committee for Clinical Laboratory Standards. Any isolate showing resistance to Oxacillin was tested again by agar dilution method to determine minimum inhibitory concentration (MIC) of Methicillin. All strains were also tested for mecA gene by Polymerase Chain Reaction (PCR) for confirmation of Methicillin resistance. Enterotoxin (A-D) and Toxic Shock Syndrome Toxin-1 (TSST-1) were detected by Reverse Passive Latex Agglutination (RPLA) test. Out of 40 S. aureus isolates, 7 (17.5%) Methicillin Resistant S. aureus (MRSA), 1 (2.5%) Methicillin Sensitive S. aureus (MSSA) produced Staphylococcal Enterotoxin A (SE-A) and 1 MRSA isolate was positive for TSST-1. In case of combined toxin production among the S. aureus isolates, 2 (5%) MSSA were found to produce SE-A and SE-B, 2 (5%) MSSA produced SE-C and SE-D, and 1 (2.5%) MRSA, 1 (2.5%) MSSA produced SE-C and TSST-1.Bangladesh J Med Microbiol 2008; 02 (02): 3-6

scholarly journals Assessment of antibiotic- and disinfectant-resistant bacteria in hospital wastewater, south Ethiopia: a cross-sectional study

2015 ◽  
Vol 9 (02) ◽  
pp. 149-156 ◽  
Author(s):  
Sintayehu Fekadu ◽  
Yared Merid ◽  
Hunachew Beyene ◽  
Wondu Teshome ◽  
Solomon Gebre-Selassie
Keyword(s):  
Pathogenic Bacteria ◽  
Cross Sectional Study ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Hospital Wastewater ◽  
Sectional Study ◽  
Cross Sectional ◽  
Wide Range

Introduction: Large quantities of antimicrobials are used in hospitals for patient care and disinfection. Antibiotics are partially metabolized and residual quantities reach hospital wastewater, exposing bacteria to a wide range of biocides that could act as selective pressure for the development of resistance. Methodology: A cross-sectional study was conducted between December 2010 and February 2011 on hospital wastewater. A total of 24 composite samples were collected on a weekly basis for bacteriological analysis and susceptibility testing. Indicator organisms and pathogenic and potentially pathogenic bacteria were found and isolated on selective bacteriologic media. Disinfectant activity was evaluated by use-dilution, and minimum inhibitory concentration (MIC) was determined by the agar dilution method. Similarly, antibiotic susceptibility tests were performed using the Kirby-Bauer disk diffusion method. Results: Pathogenic (Salmonella, Shigella, and S. aureus) and potentially pathogenic (E. coli) bacteria were detected from effluents of both hospitals. Dilution demonstrated tincture iodine to be the most effective agent, followed by sodium hypochlorite; the least active was 70% ethanol. MIC for ethanol against S. aureus and Gram-negative rods from Yirgalem Hospital (YAH) showed 4 and 3.5 log reduction, respectively. Salmonella isolates from YAH effluent were resistant to ceftriaxone, tetracycline, and doxycycline. Isolates from Hawassa University Referral Hospital (HURH) effluent were resistant to the above three antibiotics as well as gentamycin. Conclusions: Hospital effluents tested contained antibiotic-resistant bacteria, which are released into receiving water bodies, resulting in a threat to public health.

scholarly journals The study of reduced susceptibility of methicillin resistant Staphylococcus aureus to various antibiotics with special reference to glycopeptides in a tertiary care hospital in central India

2019 ◽  
Vol 6 (4) ◽  
pp. 1426
Author(s):  
Swati S. Kale ◽  
Ashwini Patil
Keyword(s):  
Staphylococcus Aureus ◽  
Tertiary Care ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Care Hospital ◽  
Diagnostic Laboratory ◽  
Disk Diffusion Method ◽  
Methicillin Resistant ◽  
Agar Dilution

Background: Staphylococcus aureus has emerged over the past several decades as a leading cause of hospital-associated and community acquired infections. Methicillin resistant S. aureus (MRSA), which are often resistant to several classes of antibiotics, is the most common cause of nosocomial infections and pose a great threat to the world. Vancomycin is regarded as the first-line drug for treatment of MRSA but resistance to this drug is being reported now a day.Methods: It was carried out for a period between January 2014 to June 2017 in the microbiology diagnostic laboratory. MRSA detection was performed by cefoxitin disk diffusion method. Screening for the vancomycin intermediate and the vancomycin resistant S. aureus (VISA and VRSA respectively) was carried out by using vancomycin screen. MIC (minimum inhibitory concentration) of vancomycin was tested by agar dilution method and E strip on all MRSA isolates.Results: A total of 287 S. aureus clinical isolates were included in the study. All MRSA were inoculated on vancomycin screen agar. Visible growth was present in 8 isolates. Five (3.73%) MRSA isolates with MIC of 4 were termed VISA (vancomycin intermediate S. aureus) by agar dilution method. Six isolates had the MIC of 4 and were termed as VISA.Conclusions: As disc diffusion method is not recommended by CLSI for S. aureus, vancomycin screen agar and MIC determination by either of the methods viz. agar dilution or E test can be used.

Sign in / Sign up

Export Citation Format

Share Document