scholarly journals Prevalence of Virulence Factors and Drug Resistance in Clinical Isolates of Enterococci: A Study from North India

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Tuhina Banerjee ◽  
Shampa Anupurba
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Virulence Factors ◽  
Virulence Genes ◽  
Vancomycin Resistance ◽  
North India ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Virulence Traits ◽  
High Level

Along with emergence of multidrug resistance, presence of several virulence factors in enterococci is an emerging concept. This study was undertaken to determine the prevalence of various virulence factors phenotypically and genotypically in enterococci and study their association with multidrug resistance. A total of 310 enterococcal isolates were studied, comprising 155E. faeciumand 155E. faecalis. Antimicrobial susceptibility testing was done by disc diffusion and agar dilution method. Hemolysin, gelatinase, biofilm production, and haemagglutination were detected phenotypically and presence of virulence genes, namely,asa1, gelE, cylA, esp, andhyl, was detected by multiplex PCR. Of the total, 47.41% isolates were high level gentamicin resistant (HLGRE) and 7.09% were vancomycin resistant (VRE). All the virulence traits studied were found in varying proportions, with majority inE. faecalis(p>0.05). Strong biofilm producers possessed eitherasa1orgelEgene.gelEsilent gene was detected in 41.37% (12/29). However, increase in resistance was associated with significant decrease in expression or acquisition of virulence genes. Further, acquisition of vancomycin resistance was the significant factor responsible for the loss of virulence traits. Though it is presumed that increased drug resistance correlates with increased virulence, acquisition of vancomycin resistance might be responsible for reduced expression of virulence traits to meet the “biological cost” relating to VRE.

scholarly journals Prevalence and characterization of extended spectrum beta-lactamase-producing Enterobacter cloacae strains in Algeria

2013 ◽  
Vol 7 (11) ◽  
pp. 804-811 ◽  
Author(s):  
Sabrina Nedjai ◽  
Abouddihaj Barguigua ◽  
Nassima Djahmi ◽  
Loubna Jamali ◽  
Khalid Zerouali ◽  
...  
Keyword(s):  
Enterobacter Cloacae ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Extended Spectrum Beta Lactamase ◽  
Agar Dilution ◽  
Synergy Test ◽  
High Level ◽  
Genomic Typing ◽  
Microbiological Data

Introduction: Expended spectrum β-lactamase (ESBL)-producing Enterobacter cloacae is an important nosocomial pathogen. In this study, the prevalence and the molecular epidemiology of ESBL producing E. cloacae strains isolated from various hospitals in Annaba, Algeria were investigated. Methodology: The study involved 63 isolates of E. cloacae obtained during 2009 at the four hospitals in Annaba. The detection of ESBL was performed using the double-disk synergy test and the combined disk test. Minimum inhibitory concentrations (MICs) were determined using the agar dilution method. The presence of blaCTX-M, blaSHV, blaTEM, and blaDHA β-lactamase genes was evaluated by PCR, and genomic typing was determined by pulsed-field gel electrophoresis (PFGE) analysis. The clinical and microbiological data were entered into the EpiI Info database. Results: Thirty isolates (47.6%) had an ESBL phenotype. BlaCTX-M group1 (76%); blaTEM (70%) were the most prevalent, followed by blaDHA (16.6%) and blaSHV (10%). Eighteen strains expressed at least two bla genes. MICs revealed a high level of resistance to cefotaxime, ceftazidime, and cefepime.  PFGE revealed an epidemic clonal dissemination of these isolates. Various risk factors associated with the occurrence of ESBL-producing E. cloacae were detected. Conclusions: A higher frequency of ESBL-producing isolates and a diversity of β-lactamases were detected among ESBL-producing E. cloacae; these resulted from an epidemic clonal dissemination and high transference of ESBL genes between bacteria in hospital settings. Strict measures will be required to control the further spread of these pathogens in hospital settings.

scholarly journals Triclosan resistance in clinical isolates of Acinetobacter baumannii

2009 ◽  
Vol 58 (8) ◽  
pp. 1086-1091 ◽  
Author(s):  
Yagang Chen ◽  
Borui Pi ◽  
Hua Zhou ◽  
Yunsong Yu ◽  
Lanjuan Li
Keyword(s):  
Acinetobacter Baumannii ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Active Efflux ◽  
Low Level ◽  
High Level ◽  
Resistance Rates ◽  
Triclosan Resistance

The susceptibility to triclosan of 732 clinical Acinetobacter baumannii isolates obtained from 25 hospitals in 16 cities in China from December 2004 to December 2005 was screened by using an agar dilution method. Triclosan MICs ranged between 0.015 and 16 mg l−1, and the MIC90 was 0.5 mg l−1, lower than the actual in-use concentration of triclosan. Twenty triclosan-resistant isolates (MICs ≥1 mg l−1) were characterized by antibiotic susceptibility, clonal relatedness, fabI mutation, fabI expression, and efflux pump phenotype and expression to elucidate the resistance mechanism of A. baumannii to triclosan. The resistance rates of triclosan-resistant isolates to imipenem, levofloxacin, amikacin and tetracycline were higher than those of triclosan-sensitive isolates. Triclosan resistance was artificially classified as low level (MICs 1–2 mg l−1) or high level (MICs ≥4 mg l−1). High-level triclosan resistance could be explained by a Gly95Ser mutation of FabI, whilst wild-type fabI was observed to be overexpressed in low-level resistant isolates. Active efflux did not appear to be a major reason for acquired triclosan resistance, but acquisition of resistance appeared to be dependent on a background of intrinsic triclosan efflux.

Ginseng aqueous extract attenuates the production of virulence factors, stimulates twitching and adhesion, and eradicates biofilms of Pseudomonas aeruginosa

2011 ◽  
Vol 89 (6) ◽  
pp. 419-427 ◽  
Author(s):  
Misagh Alipour ◽  
Abdelwahab Omri ◽  
Zacharias E. Suntres
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Aqueous Extract ◽  
North American ◽  
American Ginseng ◽  
Antimicrobial Activities ◽  
Live Cells ◽  
Dilution Method ◽  
Agar Dilution Method

This study was carried out to examine the antimicrobial activity of the aqueous extract of Panax quinquefolius from North American ginseng (NAGE) root against Pseudomonas aeruginosa . The minimum inhibitory concentrations of reference and clinical isolates of Pseudomonas aeruginosa were measured by a standard agar-dilution method. At subinhibitory NAGE concentrations, the secretion of virulence factors, motility on agar, and adhesion to 96-well microplates were studied on the nonmucoid Pseudomonas aeruginosa O1 strain. At suprainhibitory concentrations, the activity of NAGE against mature biofilm complexes formed in the Calgary Biofilm Device and the Stovall flow cell were assessed. NAGE possessed an antibacterial activity against all the Pseudomonas aeruginosa strains at 1.25%–2.5% w/v. NAGE also significantly attenuated pyocyanin, pyoverdine, and lipase concentrations, stimulated twitching, and attenuated swarming and swimming motility. At 1.25% w/v, NAGE augmented adhesion, and at 5% w/v detached 1-day-old biofilms in microplates. The extract also eradicated 6-day-old mature biofilms (5% w/v), and fluorescence microscopy displayed a reduction of live cells and biofilm complexes compared with nontreated biofilms. These data suggest that the aqueous extract from North American ginseng possesses antimicrobial activities in vitro.

scholarly journals Characterization of Clinical Isolates ofEnterococciwith Special Reference to Glycopeptide Susceptibility at a Tertiary Care Center of Eastern Nepal

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Aasish Karna ◽  
Ratna Baral ◽  
Basudha Khanal
Keyword(s):  
Multidrug Resistance ◽  
Minimum Inhibitory Concentration ◽  
Antimicrobial Susceptibility ◽  
Inhibitory Concentration ◽  
Tertiary Care ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disc Diffusion ◽  
Diffusion Technique ◽  
Agar Dilution

Background. Enterococci, once considered as a harmless commensal of intestine, have now emerged as medically important pathogens and are associated with both community-acquired and nosocomial infections. They bear the potential to exhibit resistance against all commonly used antibiotics either by inherent or acquired mechanism, posing a therapeutic challenge.Objectives. This study aimed to characterize enterococci up to the species level and study their antibiogram with special regard to vancomycin.Methods. A descriptive cross-sectional study was conducted in the Department of Microbiology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal, from February to May 2017. A total of 91 enterococcal isolates recovered from clinical specimens were investigated in this study. Their identification and speciation were done according to standard microbiological guidelines. Kirby–Bauer disc diffusion technique was used to study antimicrobial susceptibility pattern, whereas minimum inhibitory concentration of vancomycin was determined by the agar dilution method, with reference to Clinical and Laboratory Standards Institute guidelines.Results. Seven different species of enterococci were isolated,E. faecalisandE. faeciumaccounting about 45% each. The other species encountered wereE.avium,E.cecorum,E.dispar,E.durans, andE.raffinosus. Highest proportion of antimicrobial susceptibility was recorded for linezolid (97.8%), followed by teicoplanin (95.6%) and high-level gentamicin (81.3%). Sensitivity to vancomycin was seen in 79.1% isolates. Likewise, 82.1% of urinary strains were susceptible to nitrofurantoin. A total of 4 disparities were observed between the disc diffusion technique and agar dilution method in determining vancomycin resistance. Multidrug resistance was observed in 31.9% isolates. The overall prevalence of vancomycin-resistant enterococci based on the standard minimum inhibitory concentration method was 25.3%.Conclusions.Enterococcus faecalisandE. faeciumwere the predominant species in causing enterococcal infections. The alarming rise in prevalence of vancomycin and multidrug resistance strains warrants immediate, adequate, and efficient surveillance program to prevent and control its spread.

scholarly journals Detection of OXA-181/OXA-48 carbapenemase producing Enterobacteriaceae in Bangladesh

2016 ◽  
Vol 9 (2) ◽  
pp. 45-51 ◽  
Author(s):  
Rehana Khatun ◽  
SM Shamsuzzaman
Keyword(s):  
Health Concern ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
College Hospital ◽  
Medical College ◽  
Epidemiological Monitoring ◽  
Diffusion Technique ◽  
Genes Encoding ◽  
High Level ◽  
Phenotypic Tests

Carbapenem resistant Enterobacteriaceae (CRE) is becoming a major public health concern globally. Detection of carbapenem hydrolyzing enzyme carbapenemase in Enterobacteriaceae is important to institute appropriate therapy and to initiate preventive measures. This study was designed to determine the presence of carbapenemase producers among the CRE isolated from patients at Dhaka Medical College Hospital, Bangladesh. Twenty-nine CRE strains detected by disk diffusion technique were included in the study. Minimum inhibitory concentration of imipenem and tigecycline was determined by agar dilution method. Carbapenemase production was phenotypically detected by Modified Hodge test while MBL producers were detected by combined disk and double disk synergy tests. Genes encoding blaNDM-1, blaOXA-181, blaOXA-48, blaKPC, blaCTX-M-15, blaOXA-1-group were identified by polymerase chain reaction (PCR). Out of 29 CRE, nineteen (65.6%) were positive for carbapenemase by any of the three phenotypic tests namely MHT, CD or DD tests. Those 19 isolates were also positive either for blaNDM-1 or blaOXA-181/blaOXA-48 by PCR. Of the 19 PCR positive isolates, the rate of positivity for blaNDM- 1, blaOXA-181/blaOXA-48 and blaNDM-1+ blaOXA-181/blaOXA-48 was 73.7% (14/19), 57.9% (11/19) and 31.6% (6/19) respectively. Both blaOXA-181 and blaOXA-48 co-existed. All the carbapenemase producing organisms harboured blaCTX-M-15 except one C. freundii strain. The rate of resistance to different classes of antibiotics ranged from 63.2% to 100% except colistin and tigecycline. Organisms positive for OXA-181/OXA-48 had a low level of resistance to carbapenem (MIC 1 - 4 ì g/ml) while with NDM-1 had high level resistance to imipenem (MICs 16 - ? 32 ì g/ ml). Out of 19 carbapenemase positive isolates, 12 (63.16%) were extensively drug-resistant (XDR) and were only sensitive to tigecycline and colistin. The result of this study showed the presence of blaOXA-181/ blaOXA-48, blaNDM-1 positive strains in Bangladesh and colistin and tigecycline were the most effective drugs against carbapenemase producing Enterobacteriaceae (CPE). Epidemiological monitoring of carbapenemase producing organisms in Bangladesh is important to prevent their dissemination.Ibrahim Med. Coll. J. 2015; 9(2): 45-51

scholarly journals Overexpression of the Escherichia coli sugE Gene Confers Resistance to a Narrow Range of Quaternary Ammonium Compounds

2002 ◽  
Vol 184 (9) ◽  
pp. 2543-2545 ◽  
Author(s):  
Yong Joon Chung ◽  
Milton H. Saier
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Multidrug Resistance ◽  
Quaternary Ammonium ◽  
Narrow Range ◽  
Quaternary Ammonium Compounds ◽  
High Level Expression ◽  
Small Multidrug Resistance ◽  
High Level ◽  
Ammonium Compounds

ABSTRACT SugE of Escherichia coli, first identified as a suppressor of groEL mutations but a member of the small multidrug resistance family, has not previously been shown to confer a drug resistance phenotype. We show that high-level expression of sugE leads to resistance to a subset of toxic quaternary ammonium compounds.

scholarly journals Antimicrobial resistance of Enterococcus faecium and Enterococcus faecalis, isolated from blood culture of patients with hematological malignancies during different study periods

2021 ◽  
Vol 16 (1) ◽  
pp. 54-63
Author(s):  
A. V. Fedorova ◽  
G. A. Klyasova ◽  
I. N. Frolova ◽  
S. A. Khrulnova ◽  
A. V. Vetokhina ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Blood Culture ◽  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
High Susceptibility ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
High Level

Objective: to determine antimicrobial resistance of Enterococcus faecium and Enterococcus faecalis isolated from blood culture of hematological patients during different study periods.Materials and methods. Antimicrobial susceptibility of Enterococcus spp., collected as part of the multicenter study was tested by the broth microdilution method (USA Clinical and Laboratory Standards Institute (CLSI), 2018), to daptomycin by Etest (bioMeriéux, France). High-level gentamicin resistance (HLGR) and high-level streptomycin resistance (HLSR) was performed by the agar dilution method (CLSI (Oxoid, UK), 2018).Results. The susceptibility of 366 E. faecium (157 in 2002-2009 and 209 in 2010-2017) and 86 E. faecalis (44 in 20022009 and 42 in 2010-2017) was studied. In the second study period (2010-2017) the rise of vancomycin-resistant E. faecium (VREF) increased from 8.3 % to 23.4 % (p = 0.0001), and two linezolid-resistant (LREF) were identified. All VREF and LREF remained susceptible to daptomycin and tigecycline. The rate of susceptible to tetracycline E. faecium remained the same (73.9 and 74.6 %), and an increase in susceptibility to chloramphenicol (74.5 and 82.3 %) was observed. Susceptibility of E. faecium to tetracycline was detected with almost the same rate and in a part of isolates, the increase of susceptibility to chloramphenicol was registered during the analyzed periods. The rise of E. faecium susceptible to HLGR and HLSR has increased significantly in 2010-2017 compared to 2002-2009. Erythromycin, levofloxacin, ampicillin and penicillin had the least activity against E. faecium (less than 5 %).All E. faecalis were susceptible to tigecycline, linezolid, and teicoplanin. Only one of E. faecalis had intermediate resistance to vancomycin. High susceptibility to ampicillin in E. faecalis remained unchanged (97.7 and 97.6 %, respectively). In the second period of the study the rise of susceptible E. faecalis decreased significantly to penicillin (from 97.7 % to 76.2 %), to levofloxacin (from 59.1 % to 31 %), to HLSR (from 52.3 % до 31 %), and to HLGR (from 47.7 % to 26.2 %), remained unchanged to chloramphenicol (52.3 % and 50 %) and was minimal to erythromycin and tetracycline.Conclusion. The study demonstrated higher rates of antibiotic resistance among E. faecium, which consisted of an increase in VREF and the appearance of linezolid-resistant strains. High susceptibility to ampicillin remained in E. faecalis, but there was an increase in resistance to penicillin and aminoglycosides.

scholarly journals Widespread Occurrence of Possible Antibiotic Efflux Mechanism in Multidrug Resistant Intestinal E. coli Strains Isolated from Healthy Human Subjects in Bangladesh

2016 ◽  
Vol 30 (1-2) ◽  
pp. 55-59
Author(s):  
M Hasibur Rahman ◽  
Jamil Mahmud ◽  
Md Mahamudul Haque ◽  
Farzana Tarannum Tuli ◽  
Nazneen Jahan ◽  
...  
Keyword(s):  
Ethidium Bromide ◽  
Efflux Pump ◽  
Human Subjects ◽  
Agar Plate ◽  
Multidrug Resistant ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Healthy Human ◽  
Efflux Mechanism ◽  
High Level

A total of 50 isolates of Escherichia coli obtained from healthy adult human subjects were studied and tested for possible presence of efflux mechanism in resistance determination and possible correlation of plasmids with resistance.Minimal inhibitory concentration (MIC) of the antibiotics amoxicillin, azithromycin, ciprofloxacin, chloramphenicol and tetracycline were determined by agar dilution method with or without the H+/K+ proton pump inhibitor omeprazole. Plasmids were extracted by rapid alkaline plasmid extraction method and analyzed by agarose gel electrophoresis. Many strains showed 5 – 10 fold reduction of MIC values in the presence of omeprazole; a few strains showed up to 100-fold MIC reduction. Plasmid analysis of these 50 isolates revealed the presence of both plasmidless and plasmid containing strains, the latter with plasmid number varying from one to seven. However, the plasmids apparently had no relationship with high level antibiotic tolerance as indicated by the observation that some plasmidless strains had very high MIC values, while other strains containing several plasmids had very low MIC. Decrease in MIC in the presence of omeprazole apparently indicates existence of an efflux mechanism. Evidence of the efflux of ethidium bromide was noted in some strains that had been grown in ethidium bromide containing agar plate with and without omeprazole. These results suggest that reduction of MIC caused by omeprazole may be related to possible inhibition of efflux pump activity by omeprazole in the isolates studied.Bangladesh J Microbiol, Volume 30, Number 1-2,June-Dec 2013, pp 55-59

scholarly journals Community Acquired Enterococcal Urinary Tract Infections and Antibiotic Resistance Profile in North India

2016 ◽  
Vol 8 (01) ◽  
pp. 050-054 ◽  
Author(s):  
Varun Goel ◽  
Dinesh Kumar ◽  
Rajendra Kumar ◽  
Purva Mathur ◽  
Sarman Singh
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Care Hospital ◽  
Agar Dilution ◽  
High Level ◽  
Tract Infections

ABSTRACT Background: Urinary tract infections (UTIs) remain a major problem both in hospitalized and outdoor patients. Multidrug-resistant enterococci are emerging as a major nosocomial pathogen with increasing frequency. However, the incidence of community-acquired enterococcal infections and species prevalent in India is not thoroughly investigated. Objectives: This study aims to estimate the burden of community-acquired UTIs seen at a tertiary care hospital and to identify the Enterococcus species isolated from these patients. The study also aims to determine the antibiotic susceptibility pattern with reference to high-level aminoglycosides and vancomycin. Materials and Methods: Semi-quantitative cultures from a total of 22,810 urine samples obtained from patients seen at various Outpatient Departments were analyzed. From them 115 nonduplicate isolates of enterococci were obtained as significant pure growth (>105 cfu/ml) and speciated. Antibiotic susceptibility was performed by Kirby–Bauer disc diffusion method. Vancomycin resistance screening was performed by the vancomycin screen agar method recommended by Clinical and Laboratory Standards Institute and confirmed by determination of minimum inhibitory concentration by agar dilution method. Results: Of 115 enterococcal isolates, 61 were identified as Enterococcus faecalis, 42 as Enterococcus faecium, 3 each as Enterococcus dispar, and Enterococcus pseudoavium. High-level gentamicin resistance (HLGR) was higher in E. faecium (47.6%) than E. faecalis (32.7%) and HLSR also showed the same pattern with 47.6% and 27.9% resistance, respectively. Vancomycin resistant enterococci accounted for 11.3% of the isolates, and out of them 53.8% were E. faecium by agar dilution method. Conclusion: High rate of resistance to antibiotics of penicillin group and aminoglycosides was observed in our tertiary care hospital even in community acquired UTIs. Hence, there is an urgent need for more rational and restricted use of antimicrobials.

scholarly journals Emergence and Spread of Neisseria gonorrhoeae Strains with High-Level Resistance to Azithromycin in Taiwan from 2001 to 2018

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Yen-Hung Liu ◽  
Ya-Hui Wang ◽  
Chun-Hsing Liao ◽  
Po-Ren Hsueh
Keyword(s):  
Neisseria Gonorrhoeae ◽  
23S Rrna ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Coding Region ◽  
Content Type ◽  
First Choice ◽  
Agar Dilution ◽  
High Level ◽  
Level Resistance

ABSTRACT A total of 598 Neisseria gonorrhoeae isolates obtained from patients in Taiwan from 2001 to 2018 were evaluated. The MICs of ceftriaxone (CRO) and azithromycin (AZM) against the isolates were determined by the agar dilution method. N. gonorrhoeae isolates with AZM MICs of ≥1 μg/ml were identified and characterized by the presence of AZM resistance determinants. For high-level AZM-resistant (AZM-HLR) isolates (MIC ≥ 256 μg/ml), genotyping was performed using multilocus sequence typing (MLST) and N. gonorrhoeae multiantigen sequence typing (NG-MAST). Among the N. gonorrhoeae isolates studied, 8.7% (52/598) exhibited AZM MICs of ≥1 μg/ml. Thirteen of the 52 isolates contained A2059G (23S rRNA NG-STAR type 1) or C2611T (23S rRNA NG-STAR type 2) mutations. The prevalence of the A2059G mutation was higher in AZM-HLR isolates (P < 0.001). The −35A deletion in the promoter region of the mtrR gene did not differ between AZM-HLR isolates (100%, 10/10) and the isolates with AZM MICs of 1 μg/ml to 64 μg/ml (95.2%, 40/42) (P = 1.000). The presence of mutations in the mtrR coding region was significantly different between these two groups at 90% (9/10) and 26.2% (11/42), respectively (P < 0.001). The AZM-HLR isolates, all carrying four mutated A2059G alleles, a −35A deletion, and G45D, were classified as MLST 12039/10899 and NG-MAST 1866/16497. In conclusion, Taiwan is among the countries reporting gonococci with high-level resistance to AZM so that a single dose of 1 g ceftriaxone intramuscularly as the first choice for management of N. gonorrhoeae infection should be evaluated.

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