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Bacteria
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Penicillinase, an enzyme produced by several Gram-positive bacteria including Staphylococcus aureus, hydrolyses the beta-lactam ring of penicillin, resulting in penicillin resistant organisms. Development of resistance prompts a continuing need for new and chemically modified antibiotics to circumvent the problem of development of antibiotic resistant organisms.
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Published in Anton Sebastian, A Dictionary of the History of Medicine, 2018
Penicillinase Enzyme produced by Pénicillium and observed by Edward Penley Abraham (b 1913) and Ernest Boris Chain (1906–1979) in 1940. The crystallized form was obtained from Bacillus cereus by M.R. Pollock and co-workers in 1956.
Isoxazolyl Penicillins: Oxacillin, Cloxacillin, Dicloxacillin, and Flucloxacillin
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
The isoxazolyl penicillins are primarily of interest because, being resistant to staphylococcal beta-lactamase (penicillinase), they are active against staphylococci resistant to penicillin G. Resistance to this enzyme varies; some beta-lactamase-resistant penicillins are more resistant than others (Frimodt-Moller et al., 1986; Jarlov et al., 1988; Rennenberg and Forsgren, 1989). The clinical significance of this is not known, but is generally considered to be of little importance. The less common human pathogen, S. lugdunensis, may be penicillin G susceptible as many strains do not produce penicillinase. Penicillinase-producing strains are susceptible to isoxazolyl penicillins (Herchline et al., 1990; Vandenesch et al., 1993). In 2007, CLSI revised the breakpoint for coagulase-negative staphylococcus (CoNS), for all species except S. lugdunensis. With the revised breakpoints, an MIC of ≤ 0.25 mg/l is considered susceptible to oxacillin, with the exception of S. lugdunensis for which an MIC of ≤ 2 mg/l is considered susceptible. EUCAST has set the breakpoint for most CoNS at 0.125 mg/l. For S. saprophyticus and S. lugdunensis the breakpoint is 2 mg/l.
The war against bacteria, from the past to present and beyond
Published in Expert Review of Anti-infective Therapy, 2022
Lucrezia Bottalico, Ioannis Alexandros Charitos, Maria Assunta Potenza, Monica Montagnani, Luigi Santacroce
Among the first to be isolated, the MRSA appearance in Intensive Care Units has greatly impaired the successful treatment of those patients. The genes that control antibiotic resistance are usually in transposons, which confer resistance not only to methicillin (developed to treat penicillinase-producing S. aureus) but also to aminoglycosides, macrolides, tetracycline, chloramphenicol, and lincosamides [165–169]. Since these dreadful strains are also resistant to disinfectants, they may also become a major source of nosocomial infections. Similarly, to treat infections from vancomycin-resistant (VRSA) strains, drugs such as linezolid and quinopristine/dalfopristine have been developed, but their initial effectiveness has been progressively diminished [167]. For some Gram-positive bacteria, the transfer of resistance genes takes place via plasmids, and resistance may be reinforced by a combination of changes in the outer membrane barrier and in the potentiating mechanisms of drug efflux [167]. The spread of Enterococci, known for their intrinsic resistance to vancomycin, might have been facilitated by the inappropriate use of antibiotics in veterinary practice in past years [170]. Indeed, survival and multiplication of vancomycin-resistant strains of E. faecium (derived from birds) and virginiamycin-resistant strains E. faecium (derived from pigs) has been observed in the human intestinal tract [171–173]. Antibiotic-resistance to some strains of Listeria spp. seems to result from transferring of genes via plasmids and transposons [174].
Lippia graveolens HBK oleoresins, extracted by supercritical fluids, showed bactericidal activity against multidrug resistance Enterococcus faecalis and Staphylococcus aureus strains
Published in Drug Development and Industrial Pharmacy, 2021
Oscar de Jesús Calva-Cruz, Nallely S. Badillo-Larios, Antonio De León-Rodríguez, Eduardo Espitia-Rangel, Raúl González-García, Edgar Alejandro Turrubiartes-Martinez, Arnulfo Castro-Gallardo, Ana Paulina Barba de la Rosa
Galangin has been detected only in hydrolyzed methanolic extracts of L. graveolens of commercial samples [69]; however, using supercritical CO2, this compound was extracted more safely for food uses. Galangin is an efficient free radical scavenger and also exerts a protective effect on macromolecules, such as DNA, lipids, and proteins against UVB-induced damage [70]. This compound showed marked inhibitory activity against penicillinase and β-lactamase activities and cause cytoplasmic membrane damage [71]. Galangin also showed a bacteriostatic effect against MSSA (methicillin-susceptible S. aureus), MRSA (methicillin-resistant S. aureus), and VISA (vancomycin-intermediate S. aureus), independent of the mechanisms of resistance [72]. Galangin has been proposed as a novel compound to develop a new generation of phytopharmaceuticals that may use alone or in combination with other antimicrobial agents to treat highly resistant microorganisms [71].
Antibiotic susceptibility of Staphylococcus aureus isolated from skin lesions in children. A retrospective analysis from a tertiary care Italian pediatric hospital
Published in Journal of Chemotherapy, 2021
Marilea Lezzi, Roberto Bandettini, Elisabetta Ugolotti, Carolina Saffioti, Alessio Mesini, Carlotta Pastorino, Francesca Manunza, Marta Ferretti, Giacomo Brisca, Elio Castagnola
S. aureus identification was confirmed by MALDI-TOF technology (Vitek MS, BioMerieux, France), according to the manufacturer’s instructions. For each strain the susceptibility to the following antibiotics was recorded: ampicillin, methicillin, ciprofloxacin, clindamycin, cotrimoxazole, fusidic acid, mupirocin, gentamicin. The choice was made starting from the availability of results from automated tests (Vitek MS, BioMerieux, France) used routinely in our Insitute for pathogens isolated from skin lesions, and considering methicillin resistance as a standard, ampicillin as a surrogate for the presence of penicillinase and ciprofloxacin, clindamycin and cotrimoxazole as alternative drugs with an available oral formulation. Fusidic acid, mupirocin, gentamicin were also included since in Italy they have topical formulations and are frequently sold as out of the counter drugs. The interpretation of the results was based on The European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoint criteria.2