Imipenem–Cilastatin and Imipenem–Relebactam
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 in Kucers’ The Use of Antibiotics, 2017
Rhodococcus equi is usually susceptible to imipenem. For example, clinical isolates of R. equi in HIV-infected patients in 29 Spanish hospitals until 1998 were highly sensitive to imipenem (97.6%) (Torres-Tortosa et al., 2003). As Rhodococcus spp. are intracellular, In vitro susceptibility does not always equate to clinical effectiveness. Furthermore, the drug is not bactericidal against this organism. Combination with lipophilic antimicrobial agents with the ability to penetrate macrophages is needed for the treatment of this infection (Basant Arya, 2004). The imipenem–amikacin combination acts synergistically against R. equi (Nordmann et al., 1992). In vitro mutants of R. equi have been selected with decreased susceptibility to imipenem. In these, PBP3 was replaced by PBP3a, which probably explains the resistance, but the exact mechanism has not been determined (Nordmann et al., 1993).
Application of Next-Generation Plant-Derived Nanobiofabricated Drugs for the Management of Tuberculosis
Richard L. K. Glover, Daniel Nyanganyura, Rofhiwa Bridget Mulaudzi, Maluta Steven Mufamadi in Green Synthesis in Nanomedicine and Human Health, 2021
Mycobacterium tuberculosis (Mtb) is a non-motile, non-sporulating, strict aerobe, acid-fast rod that usually shows up unstained with Gram stain but, like all mycobacteria, appears stained with arylmethane dyes such as carbolfuchsin and rhodamine. It is viewed as curved bacilli microscopically with size as 1–4 µm in length and 0.3–0.6 µm in width (Sakamoto, 2012; Dunn et al., 2016). Alongside other bacteria like Corynebacterium, Nocardia and Rhodococcus, the genus Mycobacterium falls under the order Actinomycetales. As intracellular pathogenic bacteria, Mtb replicate within macrophages and monocytes, which are phagocytic cells. Many species of mycobacteria are environmental, but Mtb is an obligate parasite. In culture media, Mtb is a slow-growing species with a 12- to 24-hour cell division rate and long culture period of about 21 days on agar (Sakamoto, 2012).
Synthesis of Important Chiral Building Blocks for Pharmaceuticals Using Lactobacillus and Rhodococcus Alcohol Dehydrogenases
Peter Grunwald in Pharmaceutical Biocatalysis, 2019
Microorganisms capable of certain ketone reductions are isolated from natural sources in the search for effective biocatalysts. Rhodococcus sp. 1-0130 strain was identified for para-acetylphenol reduction to (S)-para-hydroxyphenylethanol under anaerobic conditions (Zhang et al., 2013).
Factors determining phage stability/activity: challenges in practical phage application
Published in Expert Review of Anti-infective Therapy, 2019
Ewa Jończyk-Matysiak, Norbert Łodej, Dominika Kula, Barbara Owczarek, Filip Orwat, Ryszard Międzybrodzki, Joanna Neuberg, Natalia Bagińska, Beata Weber-Dąbrowska, Andrzej Górski
Moreover, a Rhodococcus equi REQ1 phage was tested in the solid form [153]. The phage activity was retained for 60 days in pessary/suppository form and for as long as 90 days in troche form at 4°C. Phages included in tablets and powders may ensure the maintenance of phage titer and its stability when stored in low humidity [159]. However, Ly-Chatain (2014) found that phages in solid media may have limited diffusion, which may be a possible reason for reduced absorption to bacterial cells and therapeutic failure [160]. Also the KOX1 phage active against K. oxytoca had the ability to survive in stimulated gastric conditions (0.32% (wt/vol) pepsin, pH 2.5) in a troche form [161]. It was capable of retaining stability in solid forms for 90 min when the titer was reduced from 4.5 × 108 pfu/ml to 104 pfu/ml. Interestingly, the formulations had a stable titer for at least 49 days for suppositories and as long as 56 days for troches when stored at 4°C without access to light. Furthermore, the suppositories were found to contain more than 107 pfu/ml active phages. Another form of preparation intended for healing with antibacterial potential against Pseudomonas was described by Sarhan and Azzazy (2017), who presented the possibility to use a PS1 phage at a titer 109–1010 pfu/ml loaded nanofibers containing chitosan and bee venom [162].
Alternative approaches to treat bacterial infections: targeting quorum-sensing
Published in Expert Review of Anti-infective Therapy, 2020
Pipat Piewngam, Janice Chiou, Priyanka Chatterjee, Michael Otto
AHL-lactonase, a member of the metallo-β-lactamase superfamily, was first described in Bacillus sp. isolate 240B1 [117]. It cleaves the homoserine lactone ring present in AHLs in a reversible manner by hydrolysis, which renders the QS molecule incapable of binding to the target transcriptional regulator and attenuates the effectiveness of the signal molecule. Genes encoding the AHL-lactone-degrading enzyme are widespread in many bacteria, including Bacillus spp., Agrobacterium tumefaciens, Rhodococcus spp., Streptomyces spp., and Arthrobacter spp [118]. Several studies have shown that AHL lactonases can degrade AHL signals in a series of pathogenic Gram-negative bacteria, including P. aeruginosa and A. baumannii, impacting virulence and virulence-associated phenotypes [119–122],
Actinomyces causing a brain abscess
Published in Baylor University Medical Center Proceedings, 2021
Alejandro Perez, Gaurav Syngal, Samreen Fathima, Uriel Sandkovsky
Diagnosis of actinomycosis requires the recovery of Actinomyces species from an abscess, fistula, or sinus tract; histologically, they appear as colonies of filamentous bacteria with a zone of granulation tissue known as sulfur granules.1,8 Due to the slow-growing nature of the organism, cultures should be held for at least 14 days in an anaerobic environment.9 The microbiology laboratory should be informed about suspected actinomycosis.6 Branching gram-positive bacilli may indicate either aerobic Nocardia, Actinomyces, or sometimes Rhodococcus species. Actinomyces species is indistinguishable from Nocardia on Gram stain,1 but can be differentiated by special cultures and by modified acid-fast stain: Nocardia stains partially acid-fast, while Actinomyces does not.2 Differentiation of actinomycosis from nocardiosis is crucial for the selection of appropriate antimicrobial therapy.4
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