Effect of cirrhosis on antibiotic efficacy in a rat model of pneumococcal pneumonia

Osteopathic lymphatic pump techniques to enhance immunity and treat pneumonia

Pneumonia is a common cause of morbidity and mortality worldwide. While antibiotics are generally effective for the treatment of infection, the emergence of resistant strains of bacteria threatens their success. The osteopathic medical profession has designed a set of manipulative techniques called lymphatic pump techniques (LPT), to enhance the flow of lymph through the lymphatic system. Clinically, LPT is used to treat infection and oedemaand might be an effective adjuvant therapy in patients with pneumonia.The immune system uses the lymphatic and blood systems to survey to rid the body of pathogens; however, only recently have the effects of LPT on the lymphatic and immune systems been investigated. This short review highlightsclinical and basic science research studies that support the use of LPT to enhance the lymphatic and immune systems and treat pneumonia, and discusses the potential mechanisms by which LPT benefits patients with pneumonia.

Alcohol abuse and Streptococcus pneumoniae infections: consideration of virulence factors and impaired immune responses

Alcohol is the most frequently abused substance in the world. Both acute and chronic alcohol consumption have diverse and well-documented effects on the human immune system, leading to increased susceptibility to infections like bacterial pneumonia. Streptococcus pneumoniae is the most common bacterial etiology of community-acquired pneumonia worldwide. The frequency and severity of pneumococcal infections in individuals with a history of alcohol abuse is much higher than the general population. Despite this obvious epidemiological relevance, very few experimental studies have focused on the interaction of pneumococci with the immune system of a host acutely or chronically exposed to alcohol. Understanding these host-pathogen interactions is imperative for designing effective prophylactic and therapeutic interventions for such populations. Recent advances in pneumococcal research have greatly improved our understanding of pneumococcal pathogenesis and virulence mechanisms. Additionally, a large body of data is available on the effect of alcohol on the physiology of the lungs and the innate and adaptive immune system of the host. The purpose of this review is to integrate the available knowledge in these diverse areas of for a better understanding of the how the compromised immune system derived from alcohol exposure responds to pneumococcal infections.

Animal models of Streptococcus pneumoniae disease

SUMMARY

Streptococcus pneumoniae is a colonizer of human nasopharynx, but it is also an important pathogen responsible for high morbidity, high mortality, numerous disabilities, and high health costs throughout the world. Major diseases caused by S. pneumoniae are otitis media, pneumonia, sepsis, and meningitis. Despite the availability of antibiotics and vaccines, pneumococcal infections still have high mortality rates, especially in risk groups. For this reason, there is an exceptionally extensive research effort worldwide to better understand the diseases caused by the pneumococcus, with the aim of developing improved therapeutics and vaccines. Animal experimentation is an essential tool to study the pathogenesis of infectious diseases and test novel drugs and vaccines. This article reviews both historical and innovative laboratory pneumococcal animal models that have vastly added to knowledge of (i) mechanisms of infection, pathogenesis, and immunity; (ii) efficacies of antimicrobials; and (iii) screening of vaccine candidates. A comprehensive description of the techniques applied to induce disease is provided, the advantages and limitations of mouse, rat, and rabbit models used to mimic pneumonia, sepsis, and meningitis are discussed, and a section on otitis media models is also included. The choice of appropriate animal models for in vivo studies is a key element for improved understanding of pneumococcal disease.

Effect of ethanol on fluoroquinolone efficacy in a rat model of pneumococcal pneumonia

This investigation compared the effect of ethanol on fluoroquinolone antibiotic efficacy and pharmacodynamics in an ethanol-fed rat model of pneumococcal pneumonia. Male Sprague-Dawley rats received a liquid diet containing 36% of total calories as ethanol. Paired controls (pair-fed controls) were fed a liquid diet without ethanol or received rat chow. Diets began 7 days before and continued for 10 days after transtracheal infections with 10 times the 50% lethal dose of type 3 Streptococcus pneumoniae. Beginning 18 h after infection, the rats received once daily subcutaneous phosphate-buffered saline, levofloxacin, moxifloxacin, or trovafloxacin at 50 or 100 mg/kg of body weight. White blood cell counts were determined, blood samples were collected for culture, and mortality was recorded. Additional rats were killed on day 5 for pharmacodynamic studies and quantitative cultures of bronchoalveolar lavage fluid. Bacteremia occurred by day 3 in 20 of 22 untreated rats. All 22 untreated rats died by day 9. Moxifloxacin treatment was effective in all diet groups at both the 50- and 100-mg/kg doses. In contrast, 50-mg/kg doses of levofloxacin and trovafloxacin improved survival in ethanol-fed rats but were ineffective in chow-fed rats. High-dose trovafloxacin at 100 mg/kg was associated with increased mortality in pair-fed rats. The free-fraction area under the concentration-time curve/MIC ratio exceeded 50 with all antibiotics in the ethanol group but dropped below 30 with levofloxacin and trovafloxacin in the pair- and chow-fed rats, with higher mortality. Achievement of adequate antibiotic-free fraction area under the concentration-time curve/MIC ratios helps overcome ethanol-induced immune defects induced in experimental pneumococcal pneumonia.