Pneumococcus infections: is the burden still as heavy?

Altmışbeş Yaş ve Üzeri Erişkinlerde Pnömokok Bağışıklaması ve Ülkemizdeki Pnömokok Aşı Uygulamaları

Sorunu ortaya çıkmadan önlemek şüphesiz tedaviye göre kolay ve ucuz bir yöntemdir. Birinci basamak sağlık hizmetlerinin esasını oluşturan koruyucu sağlık hizmetlerinden aşılama, aşı ile önlenebilir hastalıkların önlenmesi ve bu hastalıklara bağlı kayıpların azaltılabilmesi için olmazsa olmazdır. Yaşlılarda ve yüksek riskli erişkinlerde önemli morbidite ve mortaliteye sebep olan pnömokok infeksiyonlarına karşı ülkemizde uygulanan iki tip aşı vardır: konjuge pnömokok aşısı ve polisakkarid pnömokok aşısı. Erişkinlerde pnömokok aşılarının yararı kanıtlanmış olmasına rağmen aşı uygulanma oranları hedeflenen düzeyde olmadığı için iyileştirme çalışmalarına ihtiyaç vardır. Birinci basamak çalışanları başta olmak üzere aşı uygulayıcılarının eğitilmesi ve farkındalığının artırılması, topluma aşıların yararları ve olası riskleri hakkında yeterli bilgi verilmesi, sağlık kontrollerinin ve kayıtların düzenli olması, aşıların yeterli miktarda ve ücretsiz olarak sağlanması gerekmektedir. Bu derleme erişkinlerde pnömokok aşı uygulamalarında mevcut durumu gözden geçirmek ve aşılama oranlarını arttırmak için yapılması gereken uygulamaları vurgulamak amacıyla yazılmıştır.

Streptococcus pneumoniae's Virulence and Host Immunity: Aging, Diagnostics, and Prevention

Streptococcus pneumoniae is an infectious pathogen responsible for millions of deaths worldwide. Diseases caused by this bacterium are classified as pneumococcal diseases. This pathogen colonizes the nasopharynx of its host asymptomatically, but overtime can migrate to sterile tissues and organs and cause infections. Pneumonia is currently the most common pneumococcal disease. Pneumococcal pneumonia is a global health concern and vastly affects children under the age of five as well as the elderly and individuals with pre-existing health conditions. S. pneumoniae has a large selection of virulence factors that promote adherence, invasion of host tissues, and allows it to escape host immune defenses. A clear understanding of S. pneumoniae's virulence factors, host immune responses, and examining the current techniques available for diagnosis, treatment, and disease prevention will allow for better regulation of the pathogen and its diseases. In terms of disease prevention, other considerations must include the effects of age on responses to vaccines and vaccine efficacy. Ongoing work aims to improve on current vaccination paradigms by including the use of serotype-independent vaccines, such as protein and whole cell vaccines. Extending our knowledge of the biology of, and associated host immune response to S. pneumoniae is paramount for our improvement of pneumococcal disease diagnosis, treatment, and improvement of patient outlook.

Epidemiology, virulence factors and management of the pneumococcus

Pneumococcal infections continue to cause significant morbidity and mortality in patients throughout the world. This microorganism remains the most common bacterial cause of community-acquired pneumonia and is associated with a considerable burden of disease and health-care costs in both developed and developing countries. Emerging antibiotic resistance has been a concern because of its potential negative impact on the outcome of patients who receive standard antibiotic therapy. However, there have been substantial changes in the epidemiology of this pathogen in recent years, not least of which has been due to the use of pneumococcal conjugate vaccines in children, with subsequent herd protection in unvaccinated adults and children. Furthermore, much recent research has led to a better understanding of the virulence factors of this pathogen and their role in the pathogenesis of severe pneumococcal disease, including the cardiac complications, as well as the potential role of adjunctive therapy in the management of severely ill cases. This review will describe recent advances in our understanding of the epidemiology, virulence factors, and management of pneumococcal community-acquired pneumonia.

Epidemiology and outcome of sepsis in adult patients with Streptococcus pneumoniae infection in a Norwegian county 1993-2011: an observational study

BACKGROUND

Invasive pneumococcal disease (IPD) is responsible for significant mortality and morbidity worldwide. There are however few longitudinal studies on the changes in case fatality rate of IPD in recent years. We carried out a prospective observational study of patients with IPD in Nord Trøndelag county in Norway from 1993 to 2011 to study the clinical variables and disease outcome. The main outcome was all-cause mortality after 30 and 90 days.

METHODS

Patients with positive blood cultures were registered prospectively by the microbiology laboratory and clinical variables were registered retrospectively from patients' hospital records. The severity of sepsis was assigned according to the 2001 International Sepsis Definition Conference criteria. The association between mortality and predictive factors was studied using a logistic regression model.

RESULTS

The total number of patients was 414 with mean age of 67 years and 53 % were male. Comorbidity was assessed by the Charlson Comorbidity Index (CCI). A CCI-score of 0 was registered in 144 patients (34.8 %), whereas 190 had a score of 1-2 (45.9 %) and 80 (19.3 %) had a score ≥3. 68.8 % of the patients received appropriate antibiotics within the first 6 h. The 30-day mortality risk increased by age and was 3-fold higher for patients aged ≥80 years (24.9, 95 % CI 16.4-33.4 %) compared to patients aged <70 (8.0, 95 % CI 3.5-12.4 %). 110 patients, (26.6 %) had severe sepsis and 37 (8.9 %) had septic shock. The 30 day all-cause mortality risk for those with sepsis without organ failure was 5.4 % (95 % CI 2.7-8.0 %), 20.2 % (95 % CI 13.5-27.4 %) for those with severe sepsis and 35.0 % (95 % CI 21.6-49.0 %) for those with septic shock. The mortality risk did not differ between the first and the second halves of the study period with a 30-day mortality risk of 13.5 % (95 % CI 7.9-19.2 %) for 1993-2002 versus 11.8 % (95 % CI 8.2-15.3 %) for 2003-2011.

CONCLUSION

IPD carries a high mortality despite early and appropriate antibiotics in most cases. We found no substantial decrease in case fatality rate during the study period of 18 years. Older age and higher severity of disease were important risk factors for death in IPD.

Type 1 interferon gene transfer enhances host defense against pulmonary Streptococcus pneumoniae infection via activating innate leukocytes

Pneumococcal infections are the leading cause of community-acquired pneumonia. Although the type 1 interferon-α (IFN-α) is a well-known antiviral cytokine, the role of IFN-α in antipneumococcal host defense and its therapeutic potential remain poorly understood. We have investigated these issues by using a murine transgene expression model. We found that in control animals, Streptococcus pneumoniae infection caused severe weight loss and excessive lung inflammation, associated with rapid bacterial outgrowth. In contrast, the animals that received a single dose of an adenoviral vector expressing IFN-α prior to pneumococcal infection demonstrated rapid and effective control of bacterial replication and lung inflammation and improved clinical outcome. Enhanced protection by IFN-α was due to increased activation of neutrophils and macrophages with increased release of reactive oxygen and nitrogen species and bacterial killing. Furthermore, we found that raised levels of IFN-α in the lung remained immune protective even when the gene transfer vector was given at a time postpneumococcal infection. Our study thus shows that the classically antiviral type 1 IFN can be exploited for enhancing immunity against pneumococcal infection via its activating effects on innate immune cells. Our findings hold implications for the therapeutic use of IFN-α gene transfer strategies to combat pneumococcal infections.