COVID-19: Seroprevalence and Vaccine Responses in UK Dental Care Professionals

Dental care professionals (DCPs) are thought to be at enhanced risk of occupational exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, robust data to support this from large-scale seroepidemiological studies are lacking. We report a longitudinal seroprevalence analysis of antibodies to SARS-CoV-2 spike glycoprotein, with baseline sampling prior to large-scale practice reopening in July 2020 and follow-up postimplementation of new public health guidance on infection prevention control (IPC) and enhanced personal protective equipment (PPE). In total, 1,507 West Midlands DCPs were recruited into this study in June 2020. Baseline seroprevalence was determined using a combined IgGAM enzyme-linked immunosorbent assay and the cohort followed longitudinally for 6 mo until January/February 2021 through the second wave of the coronavirus disease 2019 pandemic in the United Kingdom and vaccination commencement. Baseline seroprevalence was 16.3%, compared to estimates in the regional population of 6% to 7%. Seropositivity was retained in over 70% of participants at 3- and 6-mo follow-up and conferred a 75% reduced risk of infection. Nonwhite ethnicity and living in areas of greater deprivation were associated with increased baseline seroprevalence. During follow-up, no polymerase chain reaction-proven infections occurred in individuals with a baseline anti-SARS-CoV-2 IgG level greater than 147.6 IU/ml with respect to the World Health Organization international standard 20-136. After vaccination, antibody responses were more rapid and of higher magnitude in those individuals who were seropositive at baseline. Natural infection with SARS-CoV-2 prior to enhanced PPE was significantly higher in DCPs than the regional population. Natural infection leads to a serological response that remains detectable in over 70% of individuals 6 mo after initial sampling and 9 mo from the peak of the first wave of the pandemic. This response is associated with protection from future infection. Even if serological responses wane, a single dose of the Pfizer-BioNTech 162b vaccine is associated with an antibody response indicative of immunological memory.

Anterior cervical spine blood supply: a cadaveric study

PURPOSE

To describe the origin of the vessels supplying the anterior sub-axial cervical vertebrae (C3-C7) to further understand their potential influence on anterior bone loss after anterior cervical spinal surgery.

METHOD

Cadaveric dissection was performed on ten adult human necks after latex perfusion of their subclavian, common carotid and vertebral arteries. The nutrient vessels of the sub-axial cervical spine were identified and traced to their origin. The course and distribution of these vessels and their nutrient foraminae are described.

RESULTS

In all cases the anterior nutrient vessels were derived from the thyro-cervical trunk with branches that passed over the longus coli muscles forming a leash of vessels in the pre-vertebral fascia which subsequently extended in a frond-like pattern to pass onto the anterior aspect of vertebrae. The more cranial the cervical level the fewer the number of nutrient vessels and foraminae. The distribution of the foraminae on the anterior vertebral body followed the oblique supero-medial course of the nutrient vessels.

CONCLUSION

Nutrient vessels perforate the cervical vertebrae on their anterior surface. These are derived from a leash of vessels that lie within the pre-vertebral fascia overlying the longus coli muscles. The origin of these vessels is the ascending cervical artery with a variable contribution from the transverse cervical artery.

Venous thromboembolism rates in patients with lower limb immobilization after Achilles tendon injury are unchanged after the introduction of prophylactic aspirin: audit

ESSENTIALS: We audited venous thromboembolism (VTE) in Achilles injuries after the use of prophylactic aspirin. We audited 218 patients with Achilles injury requiring lower limb immobilization for ≥ 1 week. Fourteen patients (6.4%, 95% CI 3.6% to 10.5%) developed symptomatic and confirmed VTE. The incidence was similar to the 6.3% identified in the same patient group prior to the use of aspirin.

BACKGROUND/OBJECTIVE

We report a follow-up audit of the incidence of venous thromboembolism (VTE) in patients requiring lower limb immobilization because of Achilles tendon injury, since the introduction of a policy to routinely prescribe 100 mg of aspirin daily.

PATIENTS/METHODS

We studied 218 patients aged 18-65 years who attended the Orthopaedic Assessment Unit at Wellington Hospital between January 2013 and December 2014 with Achilles tendon injury requiring lower limb immobilization for ≥ 1 week. Information on assessment of VTE risk, prescription of aspirin and symptomatic VTE occurring within 70 days of immobilization was obtained and compared with the same information collected with the same method in the same patient group between January 2006 and December 2007, before the policy to routinely prescribe aspirin was introduced.

RESULTS

A total of 189 of 218 (93%) patients were prescribed aspirin, as compared with 0.5% previously. Fourteen patients (6.4%, 95% confidence interval 3.6-10.5%) developed symptomatic radiologically confirmed VTE (10 distal deep vein thromboses [DVTs], two proximal DVTs, one pulmonary embolism [PE], and one PE with distal DVT). Aspirin was prescribed to all patients who subsequently developed a VTE; in one of 14, a recognized risk factor was documented. The VTE incidence was similar to the 6.3% identified in the previous audit.

CONCLUSION

Lower limb immobilization following Achilles tendon injury confers a high risk of VTE even with aspirin prophylaxis. Consideration should be given to prophylaxis with low molecular weight heparin during lower limb immobilization following Achilles tendon injury, as this has proven efficacy in this clinical situation.

Observation unit treatment of heart failure with nesiritide: results from the proaction trial

This was a multicenter, randomized, double-blind, placebo-controlled pilot study, evaluating the safety and efficacy of a standard care treatment regimen with the addition of either nesiritide or placebo (SCP) in 237 Emergency Department (ED)/Observation Unit (OU) patients with decompensated heart failure (HF). Efficacy measures included initial admission, length of hospital stay (LOS), and inpatient rehospitalization through 30 days. Compared to the standard care group, patients who also received nesiritide had 11% fewer inpatient hospital admissions at the index ED visit (55% SCP, 49% nesiritide, p = 0.436), and 57% fewer inpatient hospitalizations within 30 days after discharge from the index hospitalization (23% SCP, 10% nesiritide, p = 0.058). The duration of rehospitalization was shorter for nesiritide patients (median LOS 2.5 vs. 6.5 days, p = 0.032). The incidence of symptomatic hypotension was low and did not differ between the groups. This study showed that nesiritide is safe when used in the emergency department, observation units, or similar settings.

Efficacy of Telithromycin in Community-Acquired Pneumonia Caused by Pneumococci with Reduced Susceptibility to Penicillin and/or Erythromycin

BACKGROUND

The efficacy of oral telithromycin was assessed in patients with community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae with reduced susceptibility to penicillin and/or erythromycin.

METHODS

Patients with CAP who had received telithromycin 800 mg once daily for 5 or 7-10 days (n = 2,289) in eight phase III clinical trials, or telithromycin 800 mg once daily for 7 days (n = 50) in a phase II study were included in this pooled analysis. Patients with S. pneumoniae as the cause of infection were identified, with particular focus on those infected with strains with reduced susceptibility to penicillin (intermediate, minimal inhibitory concentration (MIC) 0.12-1.0 mg/l; resistant, MIC >or=2.0 mg/l) and/or resistance to erythromycin (MIC >or=1.0 mg/l). Per-protocol clinical and bacteriological outcomes were assessed 7-14 days post-therapy in the phase III studies, and at 7-21 days post-therapy or at the end of therapy in the phase II study.

RESULTS

Of the 327 telithromycin-treated patients with S. pneumoniae infection, 61 (19%) were infected with strains with reduced susceptibility to penicillin and/or erythromycin. Clinical cure and bacterial eradication rates in these patients were 91.8% (56/61) and 93.4% (57/61), respectively. Corresponding clinical cure and bacterial eradication rates overall for all isolates of pneumococci were 94.5% (309/327) and 96.0% (314/327), respectively. All isolates with reduced susceptibility to penicillin and/or erythromycin were susceptible to telithromycin (MIC <or=1.0 mg/l).

CONCLUSION

These results indicate that telithromycin is an effective oral antibacterial for the treatment of CAP caused by pneumococci with reduced susceptibility to penicillin and/or erythromycin.

Neonatal-mouse infectivity of intact Cryptosporidium parvum oocysts isolated after optimized in vitro excystation

We reexamined the finding of Neumann et al. that intact Cryptosporidium parvum oocysts obtained after in vitro excystation were infectious for neonatal CD-1 mice. We used both established excystation protocols and our own protocol that maximized excystation. Although intact oocysts isolated after any of three protocols were infectious for neonatal CD-1 mice, the infectivity of intact oocysts isolated with our optimized excystation protocol was significantly lower than the infectivity of intact oocysts isolated after established protocols or from fresh oocysts. Excystation should not be considered a valid measure of C. parvum viability, given that it is biologically implausible for oocysts to be nonviable and yet infectious.

Telithromycin in the treatment of community-acquired pneumonia: a pooled analysis

The efficacy of telithromycin has been assessed in six Phase III studies involving adults with mild to moderate community-acquired pneumonia (CAP) with a degree of severity compatible with oral therapy. Patients received telithromycin 800 mg once daily for 7-10 days in three open-label studies (n=870) and three randomized, double-blind, comparator-controlled studies (n=503). Comparator antibacterials were amoxicillin 1000 mg three-times daily, clarithromycin 500 mg twice daily and trovafloxacin 200 mg once daily. Clinical and bacteriological outcomes were assessed 7-14 days post-therapy. Among telithromycin-treated patients, per-protocol clinical cure rates were 93.1 and 91.0% for the open-label and comparative studies, respectively. Telithromycin treatment was as effective as the comparator agents. High eradication and clinical cure rates were observed for infections caused by key pathogens: Streptococcus pneumoniae including isolates resistant to penicillin G and/or erythromycin A (95.4%), Haemophilus influenzae (89.5%) and Moraxella catarrhalis (90%). Telithromycin was also highly effective in patients with infections caused by atypical and/or intracellular pathogens and those at increased risk of morbidity. Telithromycin was generally well tolerated. Telithromycin 800 mg once daily for 7-10 days offers a convenient and well-tolerated first-line oral therapy for the empirical treatment of mild to moderate CAP.

Effectiveness of levofloxacin for adult community-acquired pneumonia caused by macrolide-resistant Streptococcus pneumoniae: integrated results from four open-label, multicenter, phase III clinical trials

BACKGROUND

The rate of macrolide resistance among Streptococcus pneumoniae clinical isolates is rising. Coresistance to several unrelated classes of antimicrobial agents is common and may limit the treatment options available for the management of infections caused by this pathogen. Although the fluoroquinolones appear to retain activity against macrolide-resistant pneumococci, limited clinical data exist to support their use in this setting.

OBJECTIVE

This study integrated data from 4 clinical trials to determine whether the fluoroquinolone levofloxacin is an effective therapeutic agent for community-acquired pneumonia (CAP) caused by macrolide-resistant S. pneumoniae.

METHODS

Across the 4 trials, 271 adult patients with CAP were diagnosed with infections caused by S. pneumoniae; these constituted the intent-to-treat population. Clinical isolates obtained from each patient at admission were tested using broth microdilution for in vitro sensitivity to the macrolide erythromycin (minimum inhibitory concentration breakpoints: susceptible, < or =0.25 microg/mL; intermediate, 0.5 microg/mL; resistant, > or =1.0 microg/mL). All patients received levofloxacin (500 mg once daily for 7-14 days) and were analyzed at a posttherapy visit (2-5 days after completion of therapy) for clinical and microbiologic outcomes; in 3 trials, patients were also examined at a poststudy visit (14-28 days after completion of treatment). Clinical and microbiologic outcomes were analyzed in patients infected with macrolide-resistant and macrolide-susceptible S. pneumoniae.

RESULTS

A total of 235 evaluable patients infected with S. pneumoniae were identified from the 4 trials. Twenty-seven (11.5%) patients were infected with isolates resistant to erythromycin, of whom 26 (96.3%) were clinical successes. By comparison, the clinical success rate in patients infected with erythromycin-susceptible isolates was 97.7%.

CONCLUSIONS

These results suggest that if future studies demonstrate the clinical relevance of macrolide resistance, levofloxacin may be a useful therapeutic option in patients with CAP caused by macrolide-resistant S. pneumoniae. However, caution may be warranted to prevent overprescription of levofloxacin and other fluoroquinolones, given the potential for the development of resistance in S. pneumoniae.

Cation selectivity of gastric H,K-ATPase and Na,K-ATPase chimeras

Chimeras of the catalytic subunits of the gastric H,K-ATPase and Na, K-ATPase were constructed and expressed in LLC-PK1 cells. The chimeras included the following: (i) a control, H85N (the first 85 residues comprising the cytoplasmic N terminus of Na,K-ATPase replaced by the analogous region of H,K-ATPase); (ii) H85N/H356-519N (the N-terminal half of the cytoplasmic M4-M5 loop also replaced); and (iii) H519N (the entire front half replaced). The latter two replacements confer a decrease in apparent affinity for extracellular K+. The 356-519 domain and, to a greater extent, the H519N replacement confer increased apparent selectivity for protons relative to Na+ at cytoplasmic sites as shown by the persistence of K+ influx when the proton concentration is increased and the Na+ concentration decreased. The pH and K+ dependence of ouabain-inhibitable ATPase of membranes derived from the transfected cells indicate that the H519N and, to a lesser extent, the H356-519N substitution decrease the effectiveness of K+ to compete for protons at putative cytoplasmic H+ activation sites. Notable pH-independent behavior of H85N/H356-519N at low Na+ suggests that as pH is decreased, Na+/K+ exchange is replaced largely by (Na+ + H+)/K+ exchange. With H519N, the pH and Na+ dependence of pump and ATPase activities suggest relatively active H+/K+ exchange even at neutral pH. Overall, this study provides evidence for important roles in cation selectivity for both the N-terminal half of the M4-M5 loop and the adjacent transmembrane helice(s).

Conformational alterations resulting from mutations in cytoplasmic domains of the alpha subunit of the Na,K-ATPase

This paper summarizes experiments concerned with the functional consequences of mutations in cytoplasmic regions of the alpha 1 subunit of the Na,K-ATPase, in particular the amino terminus, the first cytoplasmic loop between transmembrane segments M2 and M3, and the major cytoplasmic loop between M4 and M5. In the first mutation (alpha 1M32), 32 residues were removed from the N-terminus. The second mutation (E233K) was in the putative beta strand of M2-M3 loop and the third, comprised the replacement of the amino terminal half of loop M4-M5 of the Na,K-ATPase with the homologous segment (residues 356-519) of the gastric H,K-ATPase. The first two mutations, either separately or in combination (alpha 1M32E233K), shift the equilibrium between the major conformational states of the enzyme, E1 and E2, in favor of E1 as manifested by increased apparent affinity for ATP, lower catalytic turnover, and decreased sensitivity to inhibition by vanadate. The striking changes observed with alpha 1M32E233K suggests interactions between the N-terminus, the beta-strand in the M2-M3 loop and the catalytic phosphorylation site. The behavior of these mutants contrasts with that of least one mutant involving substitution of a residue in the putative cation binding pocket, namely S775A in the fifth transmembrane segment (Arguello, J.M., & Lingrel, J. B. J. Biol. Chem. 270: 22764-22771, 1995). Although its K+/ATP antagonism resembles that of the foregoing cytoplasmic mutants, its vanadate sensitivity is unaltered suggesting that changes in apparent affinity for ATP are secondary to changes in K+ ligation. The question of cation selectivity, in particular that of Na+ versus protons, has been addressed in structure/function analysis of a cytoplasmic chimera involving the M4-M5 loop. Transport studies performed in the presence or absence of Na+ and at low versus high pH indicate a marked alteration in cation affinity and/or selectivity. This results suggests coupling of an alteration in the large M4-M5 cytoplasmic domain to cation binding in, presumably, the juxtapositioned transmembrane domain.

Targeted disruption of the mouse villin gene does not impair the morphogenesis of microvilli

The small intestine is functionally dependent on the presence of the brush border, a tightly packed array of microvilli that forms the amplified apical surface of absorptive cells. In the core of each microvillus, actin filaments are bundled by two proteins, villin and fimbrin. Previous in vitro studies using antisense approaches indicated that villin plays an important role in the morphogenesis of microvilli. To examine the in vivo consequences of villin deficiency, we disrupted the mouse villin gene by targeted recombination in mouse embryonic stem cells. A beta-galactosidase cDNA was also introduced into the villin locus by the targeting event. Homozygous villin-deficient mice are viable, fertile, and display no gross abnormalities. Intact microvilli are present in the small intestine, colon, kidney proximal tubules, and liver bile canaliculi. Although subtle ultrastructural abnormalities can be detected in the actin cores of small intestinal microvilli, localization of sucrase isomaltase, brush border myosin I, and zonula occludens I to the microvillar surface of the small intestine is normal. Thus, in vivo, villin plays a minor or redundant role in the generation of microvilli in multiple absorptive tissues.

A multicenter, randomized study comparing the efficacy and safety of intravenous and/or oral levofloxacin versus ceftriaxone and/or cefuroxime axetil in treatment of adults with community-acquired pneumonia

Five hundred ninety patients were enrolled in a prospective, multicenter, randomized trial comparing the efficacy and safety of 7 to 14 days of levofloxacin treatment with that of ceftriaxone and/or cefuroxime axetil in the management of community-acquired pneumonia in adults. Patients received either intravenous and/or oral levofloxacin (500 mg once daily) or the comparative agents, parenteral ceftriaxone (1 to 2 g once to twice daily) and/or oral cefuroxime axetil (500 mg twice daily). Erythromycin or doxycycline could be added to the comparator arm at the investigator's discretion. The decision to use an intravenous or oral antimicrobial agent for initial therapy was made by the investigator. Clinical and microbiological evaluations were completed at the baseline, during treatment, 5 to 7 days posttherapy, and 3 to 4 weeks posttherapy. Four hundred fifty-six patients (226 given levofloxacin and 230 administered ceftriaxone and/or cefuroxime axetil) were evaluable for clinical efficacy. Streptococcus pneumoniae and Haemophilus influenzae were isolated in 15 and 12%, respectively, of clinically evaluable patients. One hundred fifty atypical pathogens were identified: 101 were Chlamydia pneumoniae, 41 were Mycoplasma pneumoniae, and 8 were Legionella pneumophila. Clinical success at 5 to 7 days posttherapy was superior for the levofloxacin group (96%) compared with the ceftriaxone and/or cefuroxime axetil group (90%) (95% confidence interval [CI] of -10.7 to -1.3). Among patients with typical respiratory pathogens who were evaluable for microbiological efficacy, the overall bacteriologic eradication rates were superior for levofloxacin (98%) compared with the ceftriaxone and/or cefuroxime axetil group (85%) (95% CI of -21.6 to -4.8). Levofloxacin eradicated 100% of the most frequently reported respiratory pathogens (i.e., H. influenzae and S. pneumoniae) and provided a >98% clinical success rate in patients with atypical pathogens. Both levofloxacin and ceftriaxone-cefuroxime axetil eradicated 100% of the S. pneumoniae cells detected in blood culture. Drug-related adverse events were reported in 5.8% of patients receiving levofloxacin and in 8.5% of patients administered ceftriaxone and/or cefuroxime axetil. Gastrointestinal and central and peripheral nervous system adverse events were the most common events reported in each treatment group. In conclusion, these results demonstrate that treatment with levofloxacin is superior to ceftriaxone and/or cefuroxime axetil therapy in the management of community-acquired pneumonia in adults.