scholarly journals The Odd Couple(s): An Overview of Beta-Lactam Antibiotics Bearing More Than One Pharmacophoric Group

2021 ◽  
Vol 22 (2) ◽  
pp. 617
Author(s):  
Margherita De Rosa ◽  
Anna Verdino ◽  
Annunziata Soriente ◽  
Anna Marabotti
Keyword(s):  
Antimicrobial Resistance ◽  
Large Family ◽  
Biological Properties ◽  
Beta Lactam ◽  
Chemical Modifications ◽  
Novel Weapons ◽  
Beta Lactam Antibiotics ◽  
The Common ◽  
Bifunctional Compound

β-lactam antibiotics are among the most important and widely used antimicrobials worldwide and are comprised of a large family of compounds, obtained by chemical modifications of the common scaffolds. Usually these modifications include the addition of active groups, but less frequently, molecules were synthesized in which either two β-lactam rings were joined to create a single bifunctional compound, or the azetidinone ring was joined to another antibiotic scaffold or another molecule with a different activity, in order to create a molecule bearing two different pharmacophoric functions. In this review, we report some examples of these derivatives, highlighting their biological properties and discussing how this strategy can lead to the development of innovative antibiotics that can represent either novel weapons against the rampant increase of antimicrobial resistance, or molecules with a broader spectrum of action.

scholarly journals Characterization of Multidrug Resistant Extended-Spectrum Beta-Lactamase-ProducingEscherichia coliamong Uropathogens of Pediatrics in North of Iran

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Mohammad Sadegh Rezai ◽  
Ebrahim Salehifar ◽  
Alireza Rafiei ◽  
Taimour Langaee ◽  
Mohammadreza Rafati ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Multidrug Resistant ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Beta Lactam Antibiotics ◽  
Extended Spectrum ◽  
Extended Spectrum Beta Lactamases ◽  
North Of Iran

Escherichia coliremains as one of the most important bacteria causing infections in pediatrics and producing extended-spectrum beta-lactamases (ESBLs) making them resistant to beta-lactam antibiotics. In this study we aimed to genotype ESBL-producingE. coliisolates from pediatric patients for ESBL genes and determine their association with antimicrobial resistance. One hundred of theE. coliisolates were initially considered ESBL producing based on their MIC results. These isolates were then tested by polymerase chain reaction (PCR) for the presence or absence ofCTX,TEM,SHV,GES, andVEBbeta-lactamase genes. About 30.5% of isolatedE. coliwas ESBL-producing strain. TheTEMgene was the most prevalent (49%) followed bySHV(44%),CTX(28%),VEB(8%), andGES(0%) genes. The ESBL-producingE. coliisolates were susceptible to carbapenems (66%) and amikacin (58%) and showed high resistance to cefixime (99%), colistin (82%), and ciprofloxacin (76%). In conclusion, carbapenems were the most effective antibiotics against ESBl-producingE. coliin urinary tract infection in North of Iran. The most prevalent gene is the TEM-type, but the other resistant genes and their antimicrobial resistance are on the rise.

Beta-lactam Resistance Mechanisms in Pathogens Isolated from Patients Admitted to Intensive Care Unit

2017 ◽  
Vol 68 (6) ◽  
pp. 1225-1228
Author(s):  
Carmen Axente ◽  
Delia Muntean ◽  
Luminita Baditoiu ◽  
Roxana Moldovan ◽  
Elena Hogea ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Antimicrobial Resistance ◽  
Resistance Mechanisms ◽  
University Hospital ◽  
Beta Lactam ◽  
Extended Spectrum Beta Lactamase ◽  
Beta Lactam Antibiotics ◽  
Current Context ◽  
A Prospective Study

Intensive care units (ICUs) are often referred to as the epicentre of infection diseases in a hospital. Many studies highlighted the importance of using local antimicrobial resistance data, to guide empirical antibiotic therapy. As a consequence, the present study is particularly important, especially in the current context, when we are witnessing an ascending trend of antimicrobial resistance. Beta-lactams are the most frequently used class of antibiotics for treating patients infected with various germs. The aim of this study is to analyse the modalities by which microorganisms become resistant to antibiotics of this class, in an intensive care unit of a Romanian university hospital. During the period between January, the 1st 2012 and December the 31st 2013, a prospective study was conducted in the largest ICU from the Western part of Romania. Various resistance mechanisms to beta-lactam antibiotics were detected. Among these, there is great concern regarding the high number of extended-spectrum beta-lactamase producing microorganisms, as in most cases they determine the use of carbapenems, thus increasing the risk of occurrence and dissemination of carbapenemase-producing bacteria.

scholarly journals Multiplication of ampC upon Exposure to a Beta-Lactam Antibiotic Results in a Transferable Transposon in Escherichia coli

2021 ◽  
Vol 22 (17) ◽  
pp. 9230
Author(s):  
Tania S. Darphorn ◽  
Yuanqing Hu ◽  
Belinda B. Koenders-van Sintanneland ◽  
Stanley Brul ◽  
Benno H. ter Kuile
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Variable Regions ◽  
E Coli ◽  
Beta Lactam Antibiotics ◽  
Antimicrobial Resistance Genes ◽  
Lactam Antibiotic ◽  
Lactamase Gene

Plasmids play a crucial role in spreading antimicrobial resistance genes. Plasmids have many ways to incorporate various genes. By inducing amoxicillin resistance in Escherichia coli, followed by horizontal gene transfer experiments and sequencing, we show that the chromosomal beta-lactamase gene ampC is multiplied and results in an 8–13 kb contig. This contig is comparable to a transposon, showing similarities to variable regions found in environmental plasmids, and can be transferred between E. coli cells. As in eight out of nine replicate strains an almost completely identical transposon was isolated, we conclude that this process is under strict control by the cell. The single transposon that differed was shortened at both ends, but otherwise identical. The outcome of this study indicates that as a result of exposure to beta-lactam antibiotics, E. coli can form a transposon containing ampC that can subsequently be integrated into plasmids or genomes. This observation offers an explanation for the large diversity of genes in plasmids found in nature and proposes mechanisms by which the dynamics of plasmids are maintained.

scholarly journals A Cross-Canada Surveillance of Antimicrobial Resistance in Respiratory Tract Pathogens

1999 ◽  
Vol 10 (2) ◽  
pp. 128-133 ◽  
Author(s):  
Ross J Davidson ◽  
Canadian Bacterial Surveillance Network ◽  
Donald E Low
Keyword(s):  
Antimicrobial Resistance ◽  
Clinical Laboratory ◽  
Clinical Isolates ◽  
National Committee ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Minimal Inhibitory Concentrations ◽  
Beta Lactam Antibiotics ◽  
Significant Difference ◽  
High Level

OBJECTIVE: To determine the prevalence of antimicrobial resistance in clinical isolates ofStreptococcus pneumoniae, Haemophilus influenzaeandMoraxella catarrhalisfrom medical centres across Canada.METHODS: Fifty laboratories from across Canada were asked to collect up to 25 consecutive clinical isolates ofS pneumoniae,H influenzaeandM catarrhalisat some time between September 1994 and May 1995, and then again between September and December of 1996. A total of 2364S pneumoniae, 575H influenzaeand 200M catarrhalissamples were collected.H influenzaeandM catarrhalisisolates were tested for the production of beta-lactamase.S pneumoniaeisolates were characterized as penicillin susceptible, intermediately resistant or high level penicillin-resistant. Minimal inhibitory concentrations (MICs) were determined using a microbroth dilution technique described by the National Committee of Clinical Laboratory Standards.RESULTS: Between the two collection periods, there was a significant increase in highly penicillin-resistantS pneumoniaefrom 2.1% to 4.4% (P<0.05) and an increase in intermediately penicillin-resistant strains from 6.4% to 8.9% (P<0.05). A significant increase in high level penicillin-resistantS pneumoniaewas noted among paediatric isolates. No significant difference in the susceptibilities of comparator agents was detected. A significant increase in the number of beta-lactamase producingH influenzae, 34% to 43% (P<0.05) was observed. Ninety-five per cent ofM catarrhalisisolates were beta-lactamase producers in both time periods.CONCLUSIONS: During the course of this study, the incidence of penicillin resistance inS pneumoniaedoubled. As a result of this increase, infections due to this organism in sites where poor penetration of beta-lactam antibiotics occur may become increasingly difficult to manage.

scholarly journals STAPHYLOCOCCUS AUREUS INFECTIONS AND THEIR ANTIBIOTIC SUSCEPTIBILITY PROFILE AT A TERTIARY CARE HOSPITAL

2017 ◽  
Vol 10 (12) ◽  
pp. 396
Author(s):  
Anthony N Ofulah ◽  
Shashidhar Vishwanath ◽  
Shashidhar Vishwanath ◽  
Barnini Banerjee ◽  
Shashidhar Vishwanath ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Tertiary Care ◽  
Age Groups ◽  
Bacterial Pathogen ◽  
Care Hospital ◽  
Beta Lactam ◽  
Methicillin Resistant ◽  
Inducible Clindamycin Resistance ◽  
Beta Lactam Antibiotics

  Objective: Staphylococcus aureus remains an important bacterial pathogen causing diverse infections which are both nosocomial and community acquired. Increasing resistance among S. aureus to various antibiotics is a cause of concern.Methods: A prospective observational study of 4 months duration was conducted to analyze the spectrum of infections caused by S. aureus and to study its antimicrobial resistance to commonly used antibiotics. Specimens from various clinical sites received in the laboratory for culture and sensitivity were processed as per standard techniques. Identification and susceptibility testing of S. aureus isolates were done using automated systems.Results: A total of 234 S. aureus isolates were obtained during the study period. Males accounted for 70.1% (n=164) of patients with S. aureus infections. These patients were uniformly distributed across all age groups. S. aureus was most commonly isolated from pus and exudates (64.5%) followed by respiratory specimens (20.5%) and mainly cultured from the skin and soft tissue infections (56%). Methicillin-resistant S. aureus (MRSA) accounted for 47% (n=110) of isolates. Higher rates of susceptibility were noted for tetracycline (95.3%), gentamicin (85.4%), and trimethoprim/ sulfamethoxazole (88%). Low susceptibility rate was seen for ciprofloxacin (11.2%). Inducible clindamycin resistance was seen in 22.4% (n=50) isolates. Methicillin-sensitive S. aureus isolates were found to be more susceptible to non-beta lactam antibiotics than the methicillin-resistant isolates.Conclusion: A high frequency of MRSA was found in our study. Regular surveillance of antimicrobial resistance profile of this most frequent pathogen is necessary to aid in providing appropriate empirical antibiotic therapy.

scholarly journals Multidrug-resistant Staphylococcus cohnii and Staphylococcus urealyticus isolates from German dairy farms exhibit resistance to beta-lactam antibiotics and divergent penicillin-binding proteins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tobias Lienen ◽  
Arne Schnitt ◽  
Jens Andre Hammerl ◽  
Stephen F. Marino ◽  
Sven Maurischat ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Gene Prediction ◽  
Dairy Farms ◽  
Multidrug Resistant ◽  
Amino Acid Sequences ◽  
Penicillin Binding Protein ◽  
Beta Lactam ◽  
Penicillin Binding Proteins ◽  
Antimicrobial Substances ◽  
Beta Lactam Antibiotics

AbstractNon-aureus staphylococci are commonly found on dairy farms. Two rarely investigated species are Staphylococcus (S.) cohnii and S. urealyticus. Since multidrug-resistant S. cohnii and S. urealyticus are known, they may serve as an antimicrobial resistance (AMR) gene reservoir for harmful staphylococcal species. In our study, nine S. cohnii and six S. urealyticus isolates from German dairy farms were analyzed by whole-genome sequencing and AMR testing. The isolates harbored various AMR genes (aadD1, str, mecA, dfrC/K, tetK/L, ermC, lnuA, fexA, fusF, fosB6, qacG/H) and exhibited non-wildtype phenotypes (resistances) against chloramphenicol, clindamycin, erythromycin, fusidic acid, rifampicin, streptomycin, tetracycline, tiamulin and trimethoprim. Although 14/15 isolates lacked the blaZ, mecA and mecC genes, they showed reduced susceptibility to a number of beta-lactam antibiotics including cefoxitin (MIC 4–8 mg/L) and penicillin (MIC 0.25–0.5 mg/L). The specificity of cefoxitin susceptibility testing for mecA or mecC gene prediction in S. cohnii and S. urealyticus seems to be low. A comparison with penicillin-binding protein (PBP) amino acid sequences of S. aureus showed identities of only 70–80% with regard to PBP1, PBP2 and PBP3. In conclusion, S. cohnii and S. urealyticus from selected German dairy farms show multiple resistances to antimicrobial substances and may carry unknown antimicrobial resistance determinants.

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