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Chemical Structure of the Core Region of Lipopolysaccharides
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
Hafnia alvei Only one carbohydrate backbone has been identified in the core region of several strains of Hafnia alvei (65–69). The linkage point of the O-antigen of LPS from strain 2 was identified at O-6 of the first Glc residue. In most strains, the core region carries PPE at O-4 of Hep I and phosphate residues at O-4 of Hep II. In strain 1211, Hep II is not substituted at O-6 but at O-6 by PE. Finally, it should be mentioned that from strains 32, 1192 (70), 2, and 1211 (71) the trisaccharide l,d-Hep-(1→4)-[Gal(→7)-]-Kdo was isolated, which was in the last two strains acetylated at O-6 of the Gal residue. From another strain, the linear trisaccharide Gal-(1→2)-l,d-Hep-(1→4)-Kdo was obtained (72).
Imipenem–Cilastatin and Imipenem–Relebactam
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
Yoshiro Hayashi, David L. Paterson
The Enterobacteriaceae, such as Escherichia coli, Enterobacter spp., Klebsiella spp., Proteus spp., Salmonella spp., Shigella spp., Providencia spp., Serratia spp., Citrobacter spp., Hafnia alvei, Edwardsiella spp., and Yersinia spp. are generally imipenem sensitive (Stock and Wiedemann, 2001a; Stock et al., 2002; Stock et al., 2005; Abdel-Haq et al., 2006; Deshpande et al., 2006b; Reinert et al., 2007; Turner, 2008). In recent years, carbapenem-resistant Enterobacteriaceae (and by definition, resistant to imipenem) have been increasingly observed (Paterson, 2006; Queenan and Bush, 2007). This issue will be discussed in section 2b, Emerging resistance and cross-resistance. Chromosomally mediated beta-lactamases produced by Morganella morganii, Proteus rettgeri, Serratia marcescens, and Enterobacter spp. are inducible. Imipenem acts as an inducer of these enzymes, but it is not hydrolyzed by them. So these organisms, when the enzymes are induced, remain sensitive to imipenem, but they are resistant to most third-generation cephalosporins (Labia et al., 1986; Ashby et al., 1987). Enterobacteriaceae, in particular E. coli and Klebsiella spp., which produce extended-spectrum beta-lactamases (ESBLs), may be resistant to a wide range of cephalosporins and cephamycins, but imipenem is typically effective against ESBL producers (Paterson and Bonomo, 2005) because imipenem is highly stable to beta-lactamase hydrolysis, and porin penetration is facilitated by their general size and structure. Their susceptibility to most strains of Enterobacteriaceae makes them generally useful as treatment for multidrug-resistant organisms.
Impact of antibiotic susceptibility reporting on broad spectrum antibiotic use in serratia and morganella bacteremia
Published in Journal of Chemotherapy, 2022
Wendy Hui Wen Ng, Ka Lip Chew, Joy Hui Yan Yong, Janice Xuanhui Li
In a recent in-vitro study evaluating 237 isolates by Kohlmann et al [12], the mutation rates were considerably lower in Providencia spp., Serratia spp. (2 × 10−10), and especially Morganella morganii (5 × 10−11) isolates [12]. Conversely, Enterobacter spp., Citrobacter freundii complex and Hafnia alvei isolates were found to have a high mutation rates, with a mean mutation rate of 3 × 10−8. The treatment approach to ESCPM organisms may need to be reconsidered in light of these differences. A recent review highlighted that emergence of 3rd generation cephalosporin resistance among ESCPM organisms appear to be multifactorial and not only dependent on 3rd generation cephalosporin exposure [13]. Given the heterogeneity of these organisms with regards to induction and de-repression rates, they suggest that the possibility of using 3rd generation cephalosporins for the treatment of ESCPM organism should not be dismissed.
Diagnosing COVID-19; towards a feasible COVID-19 rule-out protocol
Published in Acta Clinica Belgica, 2022
J. De Clercq, T. Malfait, S. Malfait, J. Boelens, L. Coorevits, E. Padalko, S. Vandendriessche, B. Verhasselt, L. Morbée, F. Bauters, K. Hertegonne, D. Stevens, Y. Vande Weygaerde, K. Vermaelen, W. Van Biesen, F. Vanommeslaeghe, F. Verbeke, R. Piers, N. Van Den Noortgate, T. Desmet, F. Vermassen, L. Vandekerckhove, E. Van Braeckel
Besides COVID-19 positivity or negativity, culture and multiplex rRT-PCR of BAL fluid also gave information on the presence of other microorganisms in the respiratory tract (Figure 2). In the rRT-PCR positive group, only in 1 out 7 patients, another microorganism (E. cloacae+- in culture) was identified. In the rRT-PCR negative group, other respiratory pathogens were detected in 13 (65%) of 20 patients. Culture of BAL fluid revealed the following pathogens: Klebsiella aerogenes (n = 1), Hemophilus influenzae (n = 2), Hafnia alvei (n = 1) and Escherichia coli (n = 2). Respiratory multiplex PCR identified the following bacterial microorganisms: Mycoplasma pneumoniae (n = 1), Streptococcus pneumoniae (n = 3), Hemophilus influenzae (n = 3). In addition, respiratory multiplex PCR detected the following viruses: Human coronavirus OC43 (CoV-OC43) (n = 2), Human metapneumovirus (hMPV) (n = 1), Epstein-Barr virus (EBV) (n = 1) and Rhinovirus A/B/C (n = 1). One patient was diagnosed with Pneumocystis jirovecii pneumonia, based on an additional PCR.
Aeromonas hydrophila biofilm, exoprotease, and quorum sensing responses to co-cultivation with diverse foodborne pathogens and food spoilage bacteria on crab surfaces
Published in Biofouling, 2018
Iqbal Kabir Jahid, Md. Furkanur Rahaman Mizan, Jinjong Myoung, Sang-Do Ha
In mixed-species biofilms, various foodborne bacteria communicate with and inhibit one another through the detachment of biofilm cells, jamming of quorum sensing (QS) molecules, and production of antibacterial, anti-adhesive compounds (Jahid and Ha 2014a). Recently, the addition of N-acyl homoserine lactone (AHL)-containing cultures from chicken breast muscle broth were found to have potential QS jamming and inhibition of biofilm formation effects on P. aeruginosa, which may be important for food safety (Zhang et al. 2014). Cell-free culture supernatants (CFS) of P. aeruginosa isolated from chicken meat inhibited biofilm formation by Salmonella enterica serovar Typhimurium isolated from pork- and chicken-processing surfaces (Wang et al. 2013). Additionally, the CFS of Hafnia alvei containing AHLs, but not synthetic AHLs, inhibited the early stages of biofilm formation by the Salmonella enterica serovar Enteritidis (Chorianopoulos et al. 2010). However, Almeida et al. (2017) showed that Salmonella formed stronger biofilms because of the presence of AHLs from other species.