Two Kdo-Heptose Regions Identified in Hafnia alvei 32 Lipopolysaccharide: the Complete Core Structure and Serological Screening of Different Hafnia O Serotypes▿ †

Hafnia alvei, a gram-negative bacterium, is an opportunistic pathogen associated with mixed hospital infections, bacteremia, septicemia, and respiratory diseases. Various 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo)-containing fragments different from known structures of core oligosaccharides were previously found among fractions obtained by mild acid hydrolysis of some H. alvei lipopolysaccharides (LPSs). However, the positions of these segments in the LPS structure were not known. Analysis of de-N,O-acylated LPS by nuclear magnetic resonance spectroscopy and mass spectrometry allowed the determination of the location of a Kdo-containing trisaccharide in the structure of H. alvei PCM 32 LPS. It was established that the trisaccharide {l-α-d-Hepp-(1→4)-[α-d-Galp6OAc-(1→7)]-α-Kdop-(2→} is an integral part of the outer-core oligosaccharide of H. alvei 32 LPS. The very labile ketosidic linkage between →4,7)-α-Kdop and →2)-Glcp in the core oligosaccharide was identified. Screening for this Kdo-containing trisaccharide was performed on the group of 37 O serotypes of H. alvei LPSs using monospecific antibodies recognizing the structure. It was established that this trisaccharide is a characteristic component of the outer-core oligosaccharides of H. alvei 2, 32, 600, 1192, 1206, and 1211 LPSs. The weaker cross-reactions with LPSs of strains 974, 1188, 1198, 1204, and 1214 suggest the presence of similar structures in these LPSs, as well. Thus, we have identified new examples of endotoxins among those elucidated so far. This type of core oligosaccharide deviates from the classical scheme by the presence of the structural Kdo-containing motif in the outer-core region

Comparison of serological specificity of anti-endotoxin sera directed against whole bacterial cells and core oligosaccharide of Escherichia coli J5-tetanus toxoid conjugate*.

The rough mutants of Gram-negative bacteria are widely used to induce protective antisera but the nature of the target epitope for such antibodies is not precisely defined. Endotoxin is one of several antigens present on the surface of bacterial cells, which are able to elicit specific antibodies. We studied the specificity of antibodies produced against a conjugate of E. coli J5 endotoxin core oligosaccharide with tetanus toxoid. The use of chemically defined antigen for immunisation excludes the possibility of production of antibodies against other cell surface antigens. A comparison of this monospecific anti-endotoxin serum with antiserum against E. coli J5 whole cells was performed in order to distinguish the role that endotoxin core oligosaccharide plays in the interaction with humoral host defences from that of other potentially important Gram-negative bacterial surface antigens. The reactivity of both sera with smooth and rough lipopolysaccharides was determined in ELISA, immunoblotting and by flow cytometry. Both antisera reacted with similar specificity with most lipopolysaccharides of identical or related core type. Less distinct reactions with endotoxins of the antibacterial serum in comparison with the anti-conjugate serum were found in all serological tests. LPS of E. coli O100 that showed the strongest reactions with both sera was used to stimulate IL-6, TNFα and nitric oxide production by the J-774A.1 cell line. Both sera were used to inhibit that stimulation and no inhibitory effects of the examined sera in comparison with non-immune serum were observed

Core Oligosaccharide of Plesiomonas shigelloides PCM 2231 (Serotype O17) Lipopolysaccharide — Structural and Serological Analysis

The herein presented complete structure of the core oligosaccharide of lipopolysaccharide (LPS) P. shigelloides Polish Collection of Microorganisms (PCM) 2231 (serotype O17) was investigated by 1H, 13C NMR spectroscopy, mass spectrometry, chemical analyses and serological methods. The core oligosaccharide is composed of an undecasaccharide, which represents the second core type identified for P. shigelloides serotype O17 LPS. This structure is similar to that of the core oligosaccharide of P. shigelloides strains 302-73 (serotype O1) and 7-63 (serotype O17) and differs from these only by one sugar residue. Serological screening of 55 strains of P. shigelloides with the use of serum against identified core oligosaccharide conjugated with bovine serum albumin (BSA) indicated the presence of similar structures in the LPS core region of 28 O-serotypes. This observation suggests that the core oligosaccharide structure present in strain PCM 2231 could be the most common type among P. shigelloides lipopolysaccharides

Echocardiographic Probability of Pulmonary Hypertension in Cardiac Surgery Patients—Occurrence and Association with Respiratory Adverse Events—An Observational Prospective Single-Center Study

Background: Pulmonary hypertension (PH) is an independent risk factor of increased morbidity and mortality in cardiac surgery patients (CS). The most common cause underlying PH is left ventricular (LV) diastolic dysfunction. This study aimed to evaluate the echocardiographic probability of PH in patients undergoing CS and its correlation with postoperative respiratory adverse events (RAE). Methods: The echocardiographic probability of PH and its correlation with LV diastolic dysfunction was assessed in 56 consecutive adult patients who were qualified for coronary artery bypass grafting (CABG). Later, the postoperative RAE (such as pneumonia, pulmonary congestion, or hypoxemia), the length of intensive care unit (ICU) treatment and mortality in groups with moderate or high (PH-m/h) and low (PH-l) probability of pulmonary hypertension were examined. Results: PH-m/h was observed in 29 patients, of whom 65.5 % had LV diastolic dysfunction stage II or III. A significantly higher occurrence of RAE was observed in the PH-m/h group as compared to the PH-l group. There were no differences between the PH-m/h and PH-l patient groups regarding the in-hospital length of stay or mortality. Conclusions: High or intermediate probability of PH is common in cardiac surgical patients with left ventricular diastolic dysfunction and correlates with respiratory adverse events

The Value of Clinical Frailty Scale (CFS) as a Prognostic Tool in Predicting Mortality in COVID-19—A Retrospective Cohort Study

Background: Due to the unpredictable nature of COVID-19, there is a need to identify patients at high risk of severe course of the disease and a higher mortality rate. Objective: This study aims to find the correlation between frailty and mortality in adult, hospitalized patients with COVID-19. Methods: Clinical records of 201 patients who suffered from COVID-19 and were hospitalized between October 2020 and February 2021 were retrospectively analyzed. Demographic, clinical, and biochemical data were collected. Patients were assessed using Clinical Frailty Scale (CFS) and were divided into three groups: CFS 1–3 fit; CFS 4–6 vulnerable and with mild to moderate frailty; CSF 7–9, severe frailty. The association between frailty and in-hospital mortality was the primary outcome. Results: Severe frailty or terminal illness was observed in 26 patients (12.94%) from a cohort of 201 patients. Those patients were older (median age 80.73, p < 0.001) and had more comorbidities. Frailty was also associated with higher requirement for oxygen supplementation, greater risk of in-hospital complications and worse biochemical laboratory results. An increase in CFS score also correlated with higher mortality (OR = 1.89, p < 0.001). The Conclusions: Clinical Frailty Scale (CFS) can be used as a potentially useful tool in predicting mortality in patients with COVID-19