Comparison between Ceftriaxone and Sulbactam-Ampicillin as Initial Treatment of Community-Acquired Pneumonia: A Systematic Review and Meta-Analysis

Resistance mechanism of Escherichia coli strains with different ampicillin resistance levels

Antibiotic resistance is an important problem that threatens medical treatment. Differences in the resistance levels of microorganisms cause great difficulties in understanding the mechanisms of antibiotic resistance. Therefore, the molecular reasons underlying the differences in the level of antibiotic resistance need to be clarified. For this purpose, genomic and transcriptomic analyses were performed on three Escherichia coli strains with varying degrees of adaptive resistance to ampicillin. Whole-genome sequencing of strains with different levels of resistance detected five mutations in strains with 10-fold resistance and two additional mutations in strains with 95-fold resistance. Overall, three of the seven mutations occurred as a single base change, while the other four occurred as insertions or deletions. While it was thought that 10-fold resistance was achieved by the effect of mutations in the ftsI, marAR, and rpoC genes, it was found that 95-fold resistance was achieved by the synergistic effect of five mutations and the ampC mutation. In addition, when the general transcriptomic profiles were examined, it was found that similar transcriptomic responses were elicited in strains with different levels of resistance. This study will improve our view of resistance mechanisms in bacteria with different levels of resistance and provide the basis for our understanding of the molecular mechanism of antibiotic resistance in ampicillin-resistant E. coli strains. KEY POINTS: •The mutation of the ampC promoter may act synergistically with other mutations and lead to higher resistance. •Similar transcriptomic responses to ampicillin are induced in strains with different levels of resistance. •Low antibiotic concentrations are the steps that allow rapid achievement of high antibiotic resistance.

Community-Acquired Pneumonia: A Review

Importance

Community-acquired pneumonia (CAP) results in approximately 1.4 million emergency department visits, 740 000 hospitalizations, and 41 000 deaths in the US annually.

Observations

Community-acquired pneumonia can be diagnosed in a patient with 2 or more signs (eg, temperature >38 °C or ≤36 °C; leukocyte count <4000/μL or >10 000/μL) or symptoms (eg, new or increased cough or dyspnea) of pneumonia in conjunction with consistent radiographic findings (eg, air space density) without an alternative explanation. Up to 10% of patients with CAP are hospitalized; of those, up to 1 in 5 require intensive care. Older adults (≥65 years) and those with underlying lung disease, smoking, or immune suppression are at highest risk for CAP and complications of CAP, including sepsis, acute respiratory distress syndrome, and death. Only 38% of patients hospitalized with CAP have a pathogen identified. Of those patients, up to 40% have viruses identified as the likely cause of CAP, with Streptococcus pneumoniae identified in approximately 15% of patients with an identified etiology of the pneumonia. All patients with CAP should be tested for COVID-19 and influenza when these viruses are common in the community because their diagnosis may affect treatment (eg, antiviral therapy) and infection prevention strategies. If test results for influenza and COVID-19 are negative or when the pathogens are not likely etiologies, patients can be treated empirically to cover the most likely bacterial pathogens. When selecting empirical antibacterial therapy, clinicians should consider disease severity and evaluate the likelihood of a bacterial infection-or resistant infection-and risk of harm from overuse of antibacterial drugs. Hospitalized patients without risk factors for resistant bacteria can be treated with β-lactam/macrolide combination therapy, such as ceftriaxone combined with azithromycin, for a minimum of 3 days. Systemic corticosteroid administration within 24 hours of development of severe CAP may reduce 28-day mortality.

Conclusions

Community-acquired pneumonia is common and may result in sepsis, acute respiratory distress syndrome, or death. First-line therapy varies by disease severity and etiology. Hospitalized patients with suspected bacterial CAP and without risk factors for resistant bacteria can be treated with β-lactam/macrolide combination therapy, such as ceftriaxone combined with azithromycin, for a minimum of 3 days.

Antibiotic therapy for bacterial pneumonia

Pneumonia is a common infection in patients of all ages. Determining its etiology and selecting antibiotic therapy are challenging for physicians in both private practice and hospitals. Moreover, the coronavirus disease pandemic revealed the importance of prevention and treatment of secondary bacterial pneumonia in patients hospitalized with viral respiratory infections. This review focuses on the types of bacteria that cause pneumonia and provides new insights into antibiotic therapy for bacterial pneumonia. Moreover, it also reviews the current state of knowledge regarding secondary bacterial pneumonia.

Comparison of efficacy and safety between daptomycin plus β-lactam and daptomycin monotherapy for bloodstream infections due to gram-positive cocci: A systematic review and meta-analysis

Objectives

We performed a comprehensive systematic review and meta-analysis to evaluate the clinical or microbiological outcomes and safety of a combination of daptomycin (DAP) and β-lactams compared to DAP monotherapy in patients with blood stream infection (BSI) due to gram-positive cocci (GPC).

Methods

We searched Scopus, PubMed, EMBASE, CINAHL, and Ityuushi databases up to January 30, 2023. Outcomes included all-cause mortality, clinical failure, and creatine phosphokinase (CPK) elevation.

Results

Six cohorts or case-control studies fulfilled the inclusion criteria and were included in the final meta-analysis. Combination therapy of DAP and β-lactams significantly reduced the mortality and clinical failure rate for all BSI due to GPC compared with the DAP monotherapy (mortality, odds ratio [OR] = 0.63, 95 % confidence interval [CI] = 0.41-0.98; clinical failure, OR = 0.42, 95 % CI = 0.22-0.81). In contrast, no significant difference was noted in the incidence of CPK elevation between the two groups (OR = 0.85, 95 % CI = 0.39-1.84).

Conclusion

Altogether, combination therapy of DAP and β-lactams can improve the prognosis for patients with BSI due to GPC compared with DAP alone. Therefore, it should be considered as an option for the empirical treatment of BSI caused by GPC.