The Study On The Epidemic Characters Of Community-acquired Pneumonia And Nosocomial Pneumonia In Taiyuan Area

Objective: In terms of the source of propagate, there are two types of pneumonias: community-acquired pneumonia (CAP) and nosocomial pneumonia (NP).Both have high incidence on clinic and may occur in any people. However, nowadays in China, there is still lack of the pneumonia cases reporting institution and the systematical disease surveillance system, little knowledge of epidemic strain and its changing regular pattern, and short of the further study about the pathogenic bacteria which can lead to the outbreak. So such an important issue in the prevention and control of emergence events of public health shouldn't be ignored.By the investigation about the epidemic character of pneumonia based on the hospital surveillance, the study mainly comprehended the epidemic strain and the infectious pattern of pathogenic microorganism of CAP and NP, then discovered the epidemic laws and the tendency of the CAP and NP in Taiyuan area. On the basis of the comprehensive research on the etiology character and epidemic influence factors, the study can be a scientific guide for the future changing tendency of pathogen and antimicrobial resistance and the local surveillance of CAP and NP, and can provide scientific evidence for the preventive strategy and measures of the precaution of emergency events and further surveillance task of CAP and NP .Methods: 1. A prospective study was performed on consecutive adults and children patients with CAP who were in the cooperative hospitals in Taiyuan area between December 2005 and December 2006, the samples of sputum(throat specimens) and serum of were collected for the test, meanwhile their related clinical and epidemiological data were also collected .2. The CAP patients' positive bacteria can be separated and identified by VITEK automatic analysator of microorganism. According to the guidelines of National Committee for Clinical Laboratory Standards (NCCLS), minimum inhibitory concentration(MIC) of respiratory tract isolates were determined using the agar dilution method.3. The CAP patients' samples of serum were collected to test the atypical pathogens: antibody titers to Mycoplasma pneumonia were determined by microparticle agglutination using the commercial kit Serodia-Myco II (Fujirebio, Japan), Chlamydia pneumonia was determined by the Micro-Immunofluorescent Antibody Test (EUROIMMUN) to detect IgM antibodies.The Legionella pneumonia was confirmed after the PCR used the primers to direct against species-specific sequence of the 16S ribosome gene by collecting the CAP patients' samples of sputum(throat specimens).4. A retrospective study was performed on consecutive adult patients with NP in the cooperative hospitals in Taiyuan area from January 1995 to December 2006, analyzing the distributing character and related clinical data of the adult patients with NP, adopting the methods of case-control study ,one-way and multiple factor logistic regression to select the risk factors of NP.5. The BP neural network model was built using the risk factors as the input and the NP incidence of each month as the output. The model can appraise the occurrence of NP and predict the NP incidence, it can also provide scientific evidence for the prevention and control of NP .6. A retrospective study was performed on consecutive children patients with NP in Children's Hospital of Shanxi between January 2003 and December 2005.The age distribution of children with NP, the department distribution, the underlying disease, the attack season, the distribution of pathogen and the antimicrobial resistance etc. were investigated.Results: 1. The adult patients with CAP in Taiyuan area took the elderly, soldiers and rural workers as the core finally, incidence high in spring and winter, and of frequent occurrence in the industrial and mining areas where the environmental pollution is heavier. The first three successive pathogens were streptococcus pneumonia, pneumonia mycoplasma and Legionnaires. The rate of mixed infection was 19.8%. The streptococcus pneumonia was highly resistant to penicillin and macrolides antibiotic, but extremely sensitive to the three generations' cephalosporin, glycopeptide antibiotic. Among the Patients with Mycoplasma pneumonia (MP), 63.2% of MP cases were below 30 years old and 89.5% occurred in winter and spring, and the incidence of MP patients without the underlying disease was higher than that of the patients with the underlying disease. Most of patients with the Legionella pneumonia were between 31 and 50 years old, about 53.8%of whom work or live in an environment with the airtight air condition system or cooling tower, hot water system, etc.2. Most of the children CAP patients were below 1 year old, the common pathogens were streptococcus pneumonia and pneumonia mycoplasma, the rate of mixed infection of bacteria and atypical pathogen were high, more children under the 3 years old subjected bacterial infection. The bacterial constitute about children with NP was essentially identical with the adult CAP of this area, but the proportion of streptococcus pneumonia was higher than that of the adults CAP patients. The streptococcus pneumonia was highly resistant to penicillin and macrolides antibiotic and aminoglycoside antibiotics, but extremely sensitive to Cefoperazone cefotaxime and Ceftriaxone. Atypical pathogens especially Mycoplasma pneumonia had an important role in CAP (83.7%), most of the children patients with atypical pathogens were in the 1 to 6-year-old children and were in winter and spring. While the Positive rate of Legionella pneumonia and Chlamydia pneumonia were very low.3. Through the morbidity of NP over 12 years by investigation, it can be found out that the total incidence of NP in Taiyuan area was below 1% and the case fatality was 1.9%. The adult patients with NP in Taiyuan area took the elderly as the core, incidence high in spring and winter. Gram-negative bacteria ranked first as the NP pathogenic bacteria and it was highly resistant to most of the antibiotic.4.The independent 6 risk factors of adults NP patients in Taiyuan area were as follows: Age is older than or equal to 60 years old, underlying disease, using more than two kinds of antibiotics mixedly, the therapy intensive care unit, more than 21 days in hospital stays, the use of cascade humidification system.5. By using BP artificial neural network to assess and predict the prevalence of nosocomial pneumonia in Taiyuan area, the NP morbidity of 12 months of 2006 had been predicted , compared with the actual morbidity, the coincidence rate was relatively high, error predicted was relatively little, the morbidity in January - March of 2007 had been predicted at the same time.6. Most of the children NP patients were below 1 year old, main underlying diseases were: congenital heart disease, blood disease, disease of nervous system, chromosome deformity, low weight of premature delivery, the attack seasons were winter and spring. Gram-positive bacteria occupied the first place, Main Gram-positive bacteria were highly resistant to penicillin and erythromycin, but extremely sensitive to vancomycin. Main Gram-negative bacteria were able to resistance to cephalosporin, yet sensitive to imipenem and cefoperazone/sulbactam.Conclusions: 1. The patients with CAP in Taiyuan area took the elderly and the infants who were below 1 year old as the core, streptococcus pneumonia and Mycoplasma pneumonia were the most common pathogens, atypical pathogens especially Mycoplasma pneumonia had important role in CAP, most of the patients with Mycoplasma pneumonia were the adults below 30 years old and the children between 1-6 years old, the incidence was high in spring and winter. The streptococcus pneumonia was the most common bacteria, close attention should be paid to its high drug resistance to most of the antibiotics.2. The total incidence of adults with NP in 12 years and children with NP in 3 years were below 1%, which was much lower than the related reported in domestic. Gram-negative bacteria were the main pathogen of adult with NP and able to resistance to most of the antibiotics, Gram-positive bacteria were the main pathogen of children with NP and highly resistant to penicillin and erythromycin, but extremely sensitive to vancomycin.3. The emergence of NP is influenced by a lot of factors, there are quite complicated interaction and uncertainty among these factors, BP artificial neural network has a lot of advantages can solve the complicated problems with the relationship between the variables that function can not express accurately.The research shows, this model is feasible and has its universality at the same time, it can be popularized to the appraisal of other infectious diseases of domain of hygiene and in the prediction system.4. Nowadays, there is no related research papers about this topic at home and abroad. The study investigated extensively the epidemic character, the etiology character and epidemic influence factors of pneumonia in Taiyuan area, providing scientific guide for the future changing tendency of pathogen and antimicrobial resistance and the local surveillance of CAP and NP, theoretically and factually valuable for the prevention of pneumonia and the dealing with emergence events. The study plays a positive role in Taiyuan area and may enhance the prevention of pneumonia in other cities of Shanxi province and other northern cities in China.