| BackgroundHospital infections (Nosocomial Infection, Hospital or Hospital Acquired Infection) refers to patients in hospital-acquired infections, including infections occurring during hospitalization and hospital-acquired infections that occur after discharge; but not including the infections started before admission or existing infection at the time of admission. Hospital staff in hospital-acquired infections is nosocomial infections.Before the 19th century, people believed that inevitability of infections that occur after trauma; since 19th century, namely bacteriological era, organisms were gradually recognized, and United Kingdom Lister Joseph surgeons first clarified the relationship between bacteria and infection, and the concept of sterilization. In 1928, the human succeeded in producing penicillin and entered the era of antibiotics from then on.Some hospital patients with various diseases had immune function damage and defects. Meanwhile, patients received variety of diagnostic and therapeutic operations, such as endotracheal intubation, tracheotomy urinary catheterization and so on, which increased the risk of infection. Hospital is the microbial gathering place, patients in this kind of environment increase opportunities of exposure to pathogens.The World Health Organization (WHO) figures released in 2002 showed that in 14 countries funded by its 55 hospitals the prevalence survey:patients’average prevalence rate of 8.7%. Hospitals participating in the survey represented the 4 areas: South-East Asia, Western Pacific, Eastern Mediterranean and Europe. Nosocomial infection rates in Europe and the Western Pacific region was 7.7% and 9%, respectively, and in the region of Southeast Asia and the Eastern Mediterranean,10% and 11.8%, respectively. Experts estimated that in recent years the incidence of nosocomial infections is still rising, and the situation is more serious in developing countries, the danger of 2-20 times more than developed countries. Nosocomial infection rates in some developing countries may be even more than 25%. Prevalence rate of nosocomial infection in China is between 4% and 9%.The hazards of nosocomial infection not only increase morbidity and mortality and the workload of medical staff and a patient’s pain, reduce hospital beds turnover, but also cause heavy economic losses to the patients and society. Hospital infections caused additional CFR 4%-33% according to reports. There are more than 2 million cases of nosocomial infection every year in the United States, causing additional cost of us $ 4 billion and 80,000 cases of death. Studies in developed countries show that each case of hospital infection costs us additional $ 1000-4500 for (an average of $ 1800), but in the paediatric ward especially neonatal unit additional cost can be more than$ 10000.Bacteria, fungi and viruses are the common pathogens of nosocomial infection, among which bacteria is the most common. Before the 1940s of the 20th century, nosocomial infection pathogens were all Gram-positive cocci; in the 1960s, Gram-negative bacilli gradually took the place of Gram positive cocci, becoming the main pathogens of nosocomial infection. Meanwhile, fungi, especially Candida albicans, were often detected in hospital infection. With antibiotics, especially broad-spectrum antibiotics and immunosuppressive agents broad and extensively used, drug resistance of pathogenic bacteria cannot be ignored. Methicillin-resistant Staphylococcus awreu,s(MRSA)was first reported in 1961 in United Kingdom, and then in England Extended spectrum beta lactamase (ESBL) in Gram-negative bacilli was found. Drug-resistant strains appear constantly and are increasing, which have posed a great threat to clinical treatment.Case-control study, also known as retrospective studies, is one of the most basic and the most important methods in analytical epidemiology. Patients suffered from a specific and confirmed disease was the case group, and individuals that do not suffer from the disease but is comparable serve as the control group. By questioning, laboratory test or review the history, collect previous of possible risk factors for exposure history, measured and compared each factor exposed proportion in case and control groups and make statistical tests. If the difference between the two groups has statistical significance, there is a statistically significant relationship between the factors and disease and the associated intensity can be knew. This is a method to explore the pathogens from the results, that is to say, to trace presumed causes before the disease. Thus it becomes a very useful tool in the field of research on etiology.Retrospective surveys of discharged patients in some representative clinical departments in a tertiary hospital in 2013 have been made in this article to screen the patients with nosocomial infections as the case group, and then selected the patients without hospitals infections as the control group. We describe the basic distribution of nosocomial infections. The case-control study was conducted to explore the risk factors of nonsocial infection, providing basis for prevention and control of hospital infection.ObjectiveTo explore the characteristics and risk factors of nosocomial infection in a general hospital and provide the basis for further development of infection control measures in hospitals.MethodDischarged patients in 11 representative clinical departments in a tertiary hospital were retrospectively analyzed by reviewing electronic medical record, according "the standards for diagnosis of hospital infection" by State Department of health in 2002, to screen patients of hospital infections. Clinical data records were collected and input to a spreadsheet, including basic information, infection sites, the type of specimens, pathogens detected, their drug sensitivity results, the hospitalization time, invasive procedures, types and quantities of used antibiotic, hormones, radiotherapy and chemotherapy, diseases and so on. A total of 495 cases of patients were collected. According to the clinical department,485 patients not infected at the same time were selected as the control group. Case-control study was made with the two sets of data. The results were analyzed by the software spssl7.0. Quantitative data were analyzed by t-test, the qualitative data using the X2 distribution test. A level of significance of P<0.05 was statistically significant. Using the SPSS software, analyzed the data by the univariate analysis at first, and then analyzed the selected statistically significant variables that derived from the univariate analysis by the non-conditional logistic regression model, screened the independent risk factors of nosocomial infection.Results1. A total of 36371 participants in 2013 were investigated. The infection number was 486 with 329 males and 157 females and the infection prevalence was 1.34%. The ratio of male to female was 2.10:1. The average age was 51.35±16.97 years old and the average of hospital stay was 40.36±35.34 days.2. The prevalence rate of nosocomial infection in various sections were:burn and plastic surgery 3.07%, neurosurgery 2.96%, general surgery 2.92%, hematological department 2.39%, neurology 1.14%, respiratory department 0.60%, urology 0.60%, oncology 0.43%, radiotherapy 0.42%, nephrology 0.34%, cardiovascular department 0.16%.3. The constituent ratio of infection sites was as follow:blood system 47.95%, lower respiratory tract 22.81%, incision or wound 6.82%, abdominal cavity 6.24%, skin 4.29%, biliary tract 4.09%, urinary tract 3.31%, intracranial cavity 2.53%, thoracic cavity 1.7%and the rest sites 0.78%.4. The constituent ratio of infection sites in clinical department differed greatly. For neurology patients with hospital infection,62.16%(23/37) infection sites were lower respiratory tract; for neurosurgery and oncology,73.58%(39/53) and 53.85% (7/13) infection sites were lower respiratory tract. For general surgery,57.59% (164/283) infection sites were blood system; for nephrology and urology,69.23% (18/26 and 68.75 (11/16) infection sites were bloodstream. The main infection sites were lower respiratory track (40.00%; 8/20) and blood system (55.00%; 11/20) for the patients with nosocomial infection in respiratory department. The main sites were lower respiratory track (44.44%; 4/9) and blood system (55.56%; 5/9) for the patient with nosocomial infection in intensive care unit.5. The main detected pathogens were Klebsiella pneumoniae 16.69%, Escherichia coli 16.38%, Acintobacter baumannii 13.99%, Staphylococcus aureus 8.74%, fungi 9.06%, Enterococcus 7.47%, Pseudomonas aeruginosa 7.00%, Staphylococcus epidermidis 3.02%, other coagulase negative Staphylococcus 3.34%, Enterobacter cloacae 2.54%, Proteus 1.75%, Serratia 1.75% and Morgan morgan strain 1.43%.6. The resistant rate of Klebsiella species to cefazolin, ceftriaxone and cefotaxime were 76.64%,75.21%and 74,47%, respectively. The resistant rate of Escherichia colito ampicillin, cefazolin, ceftriaxone and cefotaxime were 89.80%, 81%,78%and 79.12%. The resistant rate of Acinetobacter baumannii to cefepime, cefotetan, piperacillin, imipenem, ciprofloxacin were 93.26%,94.31%,92.20%, 91.11%,94.19%and 96.43%. The resistant rate of Pseudomonas to compound sulfamethoxazole, ampicillin tobramycin, cefepime and cefotetan were 97.83%, 58.33%,58.19%,45.83%and 45.83%. The resistant rate of Staphylococcus aureus to ciprofloxacin, levofloxacin, penicillin, clindamycin, erythroraycinand oxacillin were 82.22%,84.21%,98.28%,80.36%,83.93%and 85.96%. All of the Staphylococcus aureus were sensitive to vancomycin and Iinezolid. All the C.albicans was sensitive to fluconazole, itraconazole, voriconazole, amphotericin B and flucytosine. The resistant rate of the other fungi to the five antifungal agents were 20.00%,27.50%, 10.00%,7.50% and 5.12%.7.378 of 486 patients with nosocomial infection had empirical use of antibiotics. The most commonly used drugs were ornidazole 14.42%, imipenem 11.35%, cefotetan7.52%, biapenem 6.29%, vancomycin 6.13%.8. The top five constituent ratio of underlying diseases of the patient with nosocomial infection were malignant tumor 20.89%, intestinal fistulal2.20%, cardiovascular and cerebrovascular disease 9.34%, intestinal obstruction 5.73%, severe acute pancreatitis 5.73%.9. The univariate analysis showed that the risk factors associated with nosocomial infection were age, length of hospitalization, surgery, diabetes, cardiovascular and cerebrovascular disease, leukopenia, hypoproteinemia, anemia, gastric tube, urinary catheter, vascular intubation, ventilator, endotracheal intubation, tracheotomy, parenteral nutrition, puncture, hormone, radiotherapy, chemotherapy and hemodialysis. Non-conditional step wise logistic regression model showed that the five risk factors associated with nosocomial infection were diabetes, tracheotomy, hormone, chemotherapy and hemodialysis.Conclusion1. The top four department of nosocomial infection prevalence rate were burn and plastic surgery, neurosurgery, general surgery, hematological department. It was necessary to strengthen the monitoring of hospital infection in these departments.2. The common infection sites were blood system and lower respiratory tract. Patients from neurosurgery, neurology and oncology were prone to infection of the lower respiratory tract tumor, so it is important to strengthen the nursing care of respiratory tract of these patients. Patients from general surgery, urology and nephrology were prone to infection of blood system. For suspected sepsis patients, doctor should use antibacterial therapy as soon as possible.3. The top four pathogens detected were Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and Staphylococcus aureus.4. The resistant rate of Gram-negative bacterium to cefazolin, ceftriaxone and cefotaxime was very high. The resistant rate of Staphylococcusaureus to ciprofloxacin, levofloxacin, penicillin, clindamycin, erythromycinand oxacillin was also very high. The fungi were very susceptible to common antifungal drugs.5. Nosocomial infection occurred to patients with malignant tumor, celiac disease and cardiovascular or cerebrovascular disease which deserved more attentions.6. Risk factors associated with nosocomial infection were diabetes, tracheotomy, hormone, chemotherapy and hemodialysis. |
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