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Azithromycin
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
Unlike erythromycin, azithromycin is active against some of the Enterobacteriaceae, particularly the enteropathogens, such as enteropathogenic Escherichia coli and the Shigella and Salmonella spp. Azithromycin is particularly effective against these pathogens intracellularly (Gordillo et al., 1993; Gunell et al., 2010; Rakita et al., 1994; Retsema et al., 1987). It also has some activity against other E. coli strains, Y. enterocolitica, Leclercia adecarboxylata, Plesiomonas shigelloides, and C. diversus (Stock et al., 2004; Stock and Wiedemann, 2001). Kluyvera ascorbata is less susceptible than K. cryocrescens (Stock, 2005). Klebsiella and Enterobacter spp. and C. freundii are more resistant and the Proteus and Serratia spp. and Y. pestis are completely resistant (Retsema et al., 1987; Smith et al., 1995).
Silver as an Antimicrobial Agent: The Resistance Issue
Published in Huiliang Cao, Silver Nanoparticles for Antibacterial Devices, 2017
Kristel Mijnendonckx, Rob Van Houdt
Plasmids from the incHI incompatibility group – in which the sil gene cluster is highly conserved – are optimally transferred at temperatures below 25°C, reflecting environmental conditions such as soils and water (Maher and Taylor 1993). Consequently, they are not considered to contribute to the widespread transfer of silver resistance genes in clinical environments (Finley et al. 2015). However, they can be widespread in environmental strains, which consequently can serve as a reservoir for pathogens. Horizontal gene transfer between soil-dwelling organisms and diverse human pathogens has been demonstrated (Forsberg et al. 2012), for instance, the class A extended-spectrum β-lactamase CTX-M, found on plasmids carried by major global pathogens that were traced to environmental Kluyvera spp. (Humeniuk et al. 2002). Similarly, the quinolone resistance gene qnr, found on a broad-host range conjugative plasmid from a ciprofloxacin-resistant K. pneumoniae strain, is traced to several environmental waterborne species (Poirel et al. 2005).
Global spread and evolutionary convergence of multidrug-resistant and hypervirulent Klebsiella pneumoniae high-risk clones
Published in Pathogens and Global Health, 2023
Gabriele Arcari, Alessandra Carattoli
The detection of Extended Spectrum β-lactamases (ESBLs) genes in K. pneumoniae began shortly after the introduction of third-generation cephalosporins in the clinical practice during the first half of the 1980s [26,27] While originating from Kluyvera spp., an environmental bacterium [28,29], β-lactamases of the CTX-M family are the most prevalent ESBLs in the Enterobacterales order; in addition, these ESBLs were at the basis of the success of some K. pneumoniae STs [30].
Management of infections caused by extended-spectrum β–lactamase-producing Enterobacteriaceae: current evidence and future prospects
Published in Expert Review of Anti-infective Therapy, 2018
Chau-Chyun Sheu, Shang-Yi Lin, Ya-Ting Chang, Chun-Yuan Lee, Yen-Hsu Chen, Po-Ren Hsueh
Amber class A, D and Bush groups 2be, 2ber, 2e, and 2de comprise ESBLs. In contrast to the AmpC-type enzymes, which are mostly chromosomally encoded, inducible by antibiotic selective pressure, and unaffected by β-lactamase inhibitors (BLIs) such as clavulanate and tazobactam, ESBLs are typically carried on plasmids, able to be expressed in the absence of their substrate, and generally inhibited by BLIs. ESBLs hydrolyze penicillins, narrow- and extended-spectrum cephalosporins, and monobactam aztreonam, but the hydrolyzation of cefepime may be less efficient in some ESBLs [36]. It should also be mentioned that a smaller group of ESBLs (functional group 2ber) are ‘BLI resistant.’ The majority of ESBLs are comprised of TEM, SHV, CTM-X, and OXA families; with a smaller part from BES-1, GES-1, VEB, PER, BEL-1, SFO-1, TLA-1, TLA-2, and CME enzymes [35,37]. The TEM-type and SHV-type ESBLs are evolutionary derivatives from TEM-1, TEM-2, and SHV-1, respectively, by point mutations in the parent blaTEM-1 and blaSHV-1 genes that lead to amino acid substitutions [38]. Conversely, there is no point mutation in CTX-M, and it is believed that CTX-M arose by plasmid transfer from preexisting chromosomal ESBL genes from Kluyvera spp [39]. As the nomenclature suggests, CTX-M enzymes hydrolyze cefotaxime more efficiently than ceftazidime, and many hydrolyze cefepime as well [35,40]. The CTX-M family is divided into seven clusters based on their phylogeny: CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9, CTX-M-25 and two recently identified additional groups of CTX-M-74 and CTX-M-75 [41]. CTX-M-15 (belonged to cluster CTX-M-1 and CTX-M-9) is currently the most frequent CTX-M type ESBL in E. coli worldwide [42]. The OXA enzyme OXA-11 was the first ESBL found in the OXA family, derived from OXA-10 through mutation [43]. In addition to OXA-11, several more OXA-10 derivative ESBLs have been found, all in Pseudomonas aeruginosa: OXA-13, OXA-14 [44], OXA-16 [45], OXA-17 [46], OXA-19 [47], and OXA-28 [48].
Update on the epidemiology of carbapenemases in Latin America and the Caribbean
Published in Expert Review of Anti-infective Therapy, 2021
Juan Carlos García-Betancur, Tobias Manuel Appel, German Esparza, Ana C Gales, Gabriel Levy-Hara, Wanda Cornistein, Silvio Vega, Duilio Nuñez, Luis Cuellar, Luis Bavestrello, Paulo F. Castañeda-Méndez, Juan M. Villalobos-Vindas, María Virginia Villegas
In another publication from Colombia, Ovalle et al. [146] reported an isolate of Kluyvera cryocrescens harboring an unknown variant of blaKPC. To our knowledge, this might be the first report of a KPC-carrying K. cryocrescens isolate causing infection in humans.