Species composition and molecular-genetic characteristics of antibiotic-resistant strains of gram negative bacteria isolated from patients of a hospital’s urology department

Urologiia ◽  
2018 ◽  
Vol 1_2018 ◽  
pp. 77-83 ◽  
Author(s):  
B.U. Shalekenov Shalekenov ◽  
A.L. Bissekenova Bissekenova ◽  
B.A. Ramazanova Ramazanova ◽  
D.A. Adambekov Adambekov ◽  
S.B. Shalekenov Shalekenov ◽  
...  
Keyword(s):  
Species Composition ◽  
Molecular Genetic ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Genetic Characteristics ◽  
Gram Negative ◽  
Resistant Strains

Antibiotic Resistance as a Virulence Factor of Opportunistic Microorganisms

2021 ◽  
pp. 50-56
Author(s):  
NА Gordinskaya ◽  
EV Boriskina ◽  
DV Kryazhev
Keyword(s):  
Antibiotic Resistance ◽  
Infectious Diseases ◽  
Molecular Genetic ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Coagulase Negative Staphylococci ◽  
Genetic Studies ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Resistant Strains

Introduction: A large number of infectious processes are associated with opportunistic microorganisms. The phenotype of antibiotic resistance of such pathogens is multidrug-resistant strains with the presence of various β-lactamases. Our objective was to determine the phenotypic and genotypic features of antibiotic resistance of staphylococci, enterobacteria, and non-fermenting Gram-negative bacteria – the cause of infectious diseases in patients of various health facilities of Nizhny Novgorod. Material and methods: Using classical microbiological methods and molecular genetic studies, we analyzed 486 strains of microorganisms isolated from the upper respiratory tract, intestines, urine, and wound discharge of patients in 2019–2020. In all isolates, the phenotype of antibiotic resistance was determined by the disco-diffusion method (Bioanalyse, Turkey) and using the Multiscan FC spectrophotometer (ThermoScientific, Finland) with Microlatest tablets (PLIVA-Lachema, Czech Republic), along with molecular features of resistance mechanisms by PCR on the CFX96 device (BioRad, USA) using AmpliSens kits (Russia). Results and discussion: The results showed that the most prevalent causative agents of infectious diseases (40.7 %) were Gram-negative bacteria, of which Enterobacteriaceae and non-fermenting bacteria accounted for 27.1 % and 13.6 % of cases, respectively. Staphylococci were isolated in 37.6 % of patients: S. aureus and coagulase-negative staphylococci induced 13.4 % and 24.2 % of cases, respectively. The analysis of antibiotic resistance of the isolates showed a high level of antimicrobial resistance in all hospitals, regardless of the isolation locus. The phenotype of methicillin-resistant strains was found in 26.3 % and 37.9 % of S. aureus and coagulase-negative staphylococci, respectively; the mecA gene was found in 89.0 % of methicillin-resistant staphylococci. The highest number of antibiotic-resistant strains among Gram-negative microorganisms was observed in K. pneumoniae, A. baumannii, and P. aeruginosa. We established that 61.7 % of K. pneumoniae, 75.1 % of A. baumannii, and 58.2 % of P. aeruginosa were resistant to carbapenems. The results of molecular genetic studies confirmed the presence of serine carbapenemases KPC and OXA groups in all multidrug-resistant K. pneumoniae and A. baumannii; genes of the metallo-β-lactamase of VIM group were found in 40.9 % strains of P. aeruginosa. The production of numerous β-lactamases and the presence of determinants of antibiotic resistance in the genome determine the virulent properties of opportunistic microorganisms. Conclusion: The antibiotic resistance of opportunistic microorganisms is the cause of developing a chronic infectious process. Today, a wide spread of antibiotic-resistant infectious agents is a serious public health problem, which determines the need for constant microbiological monitoring and studies of molecular mechanisms of resistance to identify the most potent antibiotics and to determine the ways of eradication of multidrug-resistant strains.

scholarly journals Antibiotic Resistance of Gram-Negative Bacteria from Wild Captured Loggerhead Sea Turtles

Antibiotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 162 ◽  
Author(s):  
Monica Francesca Blasi ◽  
Luciana Migliore ◽  
Daniela Mattei ◽  
Alice Rotini ◽  
Maria Cristina Thaller ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Sea Turtles ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Marine Animals ◽  
Loggerhead Sea Turtles ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Marine Habitats ◽  
Resistant Strains

Sea turtles have been proposed as health indicators of marine habitats and carriers of antibiotic-resistant bacterial strains, for their longevity and migratory lifestyle. Up to now, a few studies evaluated the antibacterial resistant flora of Mediterranean loggerhead sea turtles (Caretta caretta) and most of them were carried out on stranded or recovered animals. In this study, the isolation and the antibiotic resistance profile of 90 Gram negative bacteria from cloacal swabs of 33 Mediterranean wild captured loggerhead sea turtles are described. Among sea turtles found in their foraging sites, 23 were in good health and 10 needed recovery for different health problems (hereafter named weak). Isolated cloacal bacteria belonged mainly to Enterobacteriaceae (59%), Shewanellaceae (31%) and Vibrionaceae families (5%). Although slight differences in the bacterial composition, healthy and weak sea turtles shared antibiotic-resistant strains. In total, 74 strains were endowed with one or multi resistance (up to five different drugs) phenotypes, mainly towards ampicillin (~70%) or sulfamethoxazole/trimethoprim (more than 30%). Hence, our results confirmed the presence of antibiotic-resistant strains also in healthy marine animals and the role of the loggerhead sea turtles in spreading antibiotic-resistant bacteria.

scholarly journals Virulence Determinants and Plasmid-Mediated Colistin Resistance mcr Genes in Gram-Negative Bacteria Isolated From Bovine Milk

2021 ◽  
Vol 11 ◽  
Author(s):  
Yasmine H. Tartor ◽  
Rasha M. A. Gharieb ◽  
Norhan K. Abd El-Aziz ◽  
Hend M. El Damaty ◽  
Shymaa Enany ◽  
...  
Keyword(s):  
Virulence Genes ◽  
Raw Milk ◽  
Subclinical Mastitis ◽  
Clinical Mastitis ◽  
Gram Negative Bacteria ◽  
Colistin Resistance ◽  
Genetic Characteristics ◽  
Gram Negative ◽  
E Coli ◽  
Resistant Strains

A major increase of bacterial resistance to colistin, a last-resort treatment for severe infections, was observed globally. Using colistin in livestock rearing is believed to be the ground of mobilized colistin resistance (mcr) gene circulation and is of crucial concern to public health. This study aimed to determine the frequency and virulence characteristics of colistin-resistant Gram-negative bacteria from the milk of mastitic cows and raw unpasteurized milk in Egypt. One hundred and seventeen strains belonging to Enterobacteriaceae (n = 90), Pseudomonas aeruginosa (n = 10), and Aeromonas hydrophila (n = 17) were screened for colistin resistance by antimicrobial susceptibility testing. The genetic characteristics of colistin-resistant strains were investigated for mcr-1–9 genes, phylogenetic groups, and virulence genes. Moreover, we evaluated four commonly used biocides in dairy farms for teat disinfection toward colistin-resistant strains. Multidrug-resistant (MDR) and extensive drug-resistant (XDR) phenotypes were detected in 82.91% (97/117) and 3.42% (4/117) of the isolates, respectively. Of the 117 tested isolates, 61 (52.14%) were colistin resistant (MIC >2 mg/L), distributed as 24/70 (34.29%) from clinical mastitis, 10/11 (90.91%) from subclinical mastitis, and 27/36 (75%) from raw milk. Of these 61 colistin-resistant isolates, 47 (19 from clinical mastitis, 8 from subclinical mastitis, and 20 from raw milk) harbored plasmid-borne mcr genes. The mcr-1 gene was identified in 31.91%, mcr-2 in 29.79%, mcr-3 in 34.04%, and each of mcr-4 and mcr-7 in 2.13% of the colistin-resistant isolates. Among these isolates, 42.55% (20/47) were E. coli, 21.28% (10/47) A. hydrophila, 19.12% (9/47) K. pneumoniae, and 17.02% (8/47) P. aeruginosa. This is the first report of mcr-3 and mcr-7 in P. aeruginosa. Conjugation experiments using the broth-mating technique showed successful transfer of colistin resistance to E. coli J53-recipient strain. Different combinations of virulence genes were observed among colistin-resistant isolates with almost all isolates harboring genes. Hydrogen peroxide has the best efficiency against all bacterial isolates even at a low concentration (10%). In conclusion, the dissemination of mobile colistin resistance mcr gene and its variants between MDR- and XDR-virulent Gram-negative isolates from dairy cattle confirms the spread of mcr genes at all levels; animals, humans, and environmental, and heralds the penetration of the last-resort antimicrobial against MDR bacteria. Consequently, a decision to ban colistin in food animals is urgently required to fight XDR and MDR bacteria.

Monitoring of the leading causative agents of osteomyelitis and their antibiotic resistance

2020 ◽  
Vol 65 (9) ◽  
pp. 562-566
Author(s):  
I. V. Shipitsyna ◽  
E. V. Osipova ◽  
O. A. Astashova ◽  
D. S. Leonchuk
Keyword(s):  
Antibiotic Resistance ◽  
Species Composition ◽  
Antibiotic Sensitivity ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Methicillin Resistant ◽  
Causative Agents ◽  
Resistant Strains ◽  
Bacterial Associations

The annual monitoring of the species composition of the causative agents of osteomyelitis, the identification of antibiotic-resistant strains, the study of the species composition of associations of microorganisms, their adhesive activity will prevent the spread of infection. Analyze the spectrum of the leading causative agents of osteomyelitis, their antibiotic sensitivity, and also the adhesive activity of the identified bacterial associations. A microbiological analysis of 2197 smears of adult patients with various etiological forms of osteomyelitis who were treated in the departments of the purulent center of the FSBI «NMRCTO» of the RF Ministry of Health in 2019. The spectrum of pathogenic microflora, sensitivity to standard antibacterial drugs used in the clinic was studied. The biofilm-forming ability of associations of microorganisms was investigated. According to the conducted microbiological monitoring for 2019, the microflora spectrum for osteomyelitis is diverse, the main pathogens are S. aureus, S. epidermidis, P. aeruginosa, K. pneumoniae, Enterococcus sp. A high percentage of isolation of microbial associations was noted, most often mix cultures of gram-positive and gram-negative bacteria. Bacterial associations: S. aureus + P. aeruginosa, S. aureus + S. marcescens, S. aureus + A. baumannii, S. epidermidis + E. cloacae - actively formed a biofilm on the surface of polystyrene plates, and the adhesive potential depended on interstrain relations in the composition of the formed biofilm. Among Gram-negative microflora, multiresistant strains prevail, among Gram-positive microflora - a high percentage of methicillin-resistant Staphylococci. When analyzing the antibiotic sensitivity of the isolated microorganisms, a high percentage of resistant strains is noted. So, with respect to enterobacteria, β-lactam antibiotics, drugs from the group of aminoglycosides, turned out to be ineffective. Among non-fermenting gram-negative bacteria, A. baumannii strains had multiple antimicrobial resistance. Among gram-positive microorganisms, a high percentage of isolation of methicillin-resistant staphylococci was noted. The specificity of the course of the disease and measures aimed at eliminating the pathogen depend on the species composition in the focus of infection. The study of the etiological structure of osteomyelitis, the monitoring of the antibiotic resistance of pathogens and their persistent potential, makes it possible to adopt sound tactics of conservative and surgical treatment.

scholarly journals Nosocomial klebsiellas: I. Colonization of hospitalized patients

1979 ◽  
Vol 82 (2) ◽  
pp. 177-193 ◽  
Author(s):  
Michael L. Haverkorn ◽  
M. F. Michel
Keyword(s):  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Biochemical Tests ◽  
Survey Period ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Epidemiological Tool ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
Systemic Antibiotics

SUMMARYThe colonization of patients byKlebsiellaand several other gram-negative bacteria was studied in a hospital urological ward over a period of six months. Before and during the survey there was no evidence of an outbreak of nosocomial infection and multi-drug resistant strains ofKlebsiellawere not isolated.Klebsiellawere biotyped by nine biochemical tests, which led to the detection of 66 biotypes spread uniformly throughout the survey period. This method of biotyping proved a useful epidemiological tool. The colonization rate of throats, hands, and faeces of patients increased after admission to the ward, especially when antibiotics were used. The effect of systemic antibiotics was greater than that of urinary antibiotics especially on throat and faeces carrier rates. Carrier rates forKlebsiellaincreased also after catheterization and operation – relationships which could well be multifactorial.During the first two weeks after admission the proportion of antibiotic resistant strains ofKlebsiellain carriers increased. The proportion of resistant strains amongst isolations from clinical infections was always greater than among strains isolated routinely from sites of carriage.

Bacterial resistance to disinfectants

2002 ◽  
Vol 3 (3) ◽  
pp. 22-24 ◽  
Author(s):  
AD Russell
Keyword(s):  
Bacterial Resistance ◽  
Organic Soil ◽  
Bacterial Spores ◽  
Gram Negative Bacteria ◽  
Mycobacterium Chelonae ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Gram Positive Cocci

A ntiseptics and disinfectants (biocides) are widely employed in controlling hospital infection. Their activity depends upon several factors, notably concentration, period of contract, pH, temperature, the type, nature and numbers of microorganisms to be inactivated and the presence of organic soil or other interfering material. Bacteria vary considerably in their response to antiseptics and disinfectants. Bacterial spores are the least susceptible, followed by mycobacteria (including glutaraldehyde-resistant Mycobacterium chelonae) and then by Gram-negative bacteria, notably pseudomonads. Gram-positive cocci, including antibiotic-resistant staphylococci, are readily inactivated by disinfectants. Enterococci, including vancomycin-resistant strains, are also susceptible but somewhat less so than staphylococci. Resistance is often intrinsic in nature, but may be acquired either by mutation or by the acquisition of genetic elements. Disinfectant rotation is practised in several hospitals but the issue remains contentious, although hospital isolates are often more resistant to biocides than laboratory or ‘standard’ strains.

scholarly journals Antimicrobial Peptide Novicidin Synergizes with Rifampin, Ceftriaxone, and Ceftazidime against Antibiotic-Resistant EnterobacteriaceaeIn Vitro

2015 ◽  
Vol 59 (10) ◽  
pp. 6233-6240 ◽  
Author(s):  
Odel Soren ◽  
Karoline Sidelmann Brinch ◽  
Dipesh Patel ◽  
Yingjun Liu ◽  
Alexander Liu ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Bacterial Infections ◽  
New Drugs ◽  
Gram Negative Bacteria ◽  
Cationic Antimicrobial Peptide ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Resistant Strains ◽  
Multiple Strains

ABSTRACTThe spread of antibiotic resistance among Gram-negative bacteria is a serious clinical threat, and infections with these organisms are a leading cause of mortality worldwide. Traditional novel drug development inevitably leads to the emergence of new resistant strains, rendering the new drugs ineffective. Therefore, reviving the therapeutic potentials of existing antibiotics represents an attractive novel strategy. Novicidin, a novel cationic antimicrobial peptide, is effective against Gram-negative bacteria. Here, we investigated novicidin as a possible antibiotic enhancer. The actions of novicidin in combination with rifampin, ceftriaxone, or ceftazidime were investigated against 94 antibiotic-resistant clinical Gram-negative isolates and 7 strains expressing New Delhi metallo-β-lactamase-1. Using the checkerboard method, novicidin combined with rifampin showed synergy with >70% of the strains, reducing the MICs significantly. The combination of novicidin with ceftriaxone or ceftazidime was synergistic against 89.7% of the ceftriaxone-resistant strains and 94.1% of the ceftazidime-resistant strains. Synergistic interactions were confirmed using time-kill studies with multiple strains. Furthermore, novicidin increased the postantibiotic effect when combined with rifampin or ceftriaxone. Membrane depolarization assays revealed that novicidin alters the cytoplasmic membrane potential of Gram-negative bacteria.In vitrotoxicology tests showed novicidin to have low hemolytic activity and no detrimental effect on cell cultures. We demonstrated that novicidin strongly rejuvenates the therapeutic potencies of ceftriaxone or ceftazidime against resistant Gram-negative bacteriain vitro. In addition, novicidin boosted the activity of rifampin. This strategy can have major clinical implications in our fight against antibiotic-resistant bacterial infections.

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