Epidemiological Study On Nosocomial Methicillin Resistant Staphylococcus Aureus (MRSA) In Putuo District, Shanghai

Epidemiological Study on Nosocomial Methicillin Resistant Staphylococcus Aureus(MRSA) in Putuo district,ShanghaiMethicillin-resistant Staphylococcus aureus(MRSA) are currently one of the most important drug-resistant bacteria in hospital infection,whose accounting for detection rate of clinical isolates of Staphylococcus aureus from the initial ratio of 5% up to 89.47%in some hospital.In recent years,MRSA infection is characterized by the prevalence,mortality continuing to rise,and the drug resistance rate also.It has been reported that MRSA infection and hepatitis B,AIDS is called the current world of infectious diseases 3,and that has aroused the global medical profession attach great importance to it.This study is to investigate the status of nosocomial MRSA infection in general hospitals in Putuo District,Shanghai and to make use of case-control study to investigate risk factors for MRSA,in order to provide basic information for effective control of clinical MRSA infection.The study consist of two parts:PartⅠ:Prevalence study of nosocomial MRSA infectionsObjective:To investigate nosocomial MRSA infection rates,clinical characteristics, drug resistance and demography distribution in General hospitals in Putuo District, Shanghai,for clinical to provide a basis to control MRSA infections.Methods:Search medical history of all patients discharged from four General hospital in Putuo District,Shanghai from January 1,2008 to December 31,and identify nosocomial MRSA-infected persons to investigate its prevalence,clinical characteristics,drug resistance and demography distribution for analysis. Results:In the 75,871 hospital discharge cases of the four general hospital there are 3,362 people of hospital infection(HI).Hospital infection rate is 5.15%.248 cases belong to Staphylococcus aureus infection,one of 203 people infected with MRSA. the detection rate of 81.85%,and the rest for the methicillin-sensitive Staphylococcus aureus(MSSA) is 45 cases(18.15%).Among 203 cases of inpatients with MRSA infection,119 cases of male.84 cases of female.median age is76 years old.mainly distributed in the ICU(32.5%).surgery(19.7%).Hematologists(7.4%).In 2008 the average hospital nosocomial MRSA infection rate was 2.68‰,neurological intensive care unit(NICU) of the highest infection rate for the 29.5‰,followed by General ICU(22.3‰) and coronary intensive care unit(CCU) 14.7%.MRSA infection rate higher than the average is neurosurgery department also(7.7%),the blood of internal medicine(4.7‰),department of respiratory medicine(3.3‰).The investigation reveal that the infection rate of January(4.98‰) and Febuary(4.86%) is relatively high,forming a peak,in August for the month prevalence 3.24%,the formation of a small peak.Patients with lung infection in 101 cases,accounting for 49.8%,followed by 39 cases of wound infection(19.2%),26 cases of septicemia(12.8%).Length of stay in hospital with the longest days before infection is 80 days,the shortest is 4 days, the average is 21.45d±16.72d.T test reveals,it is 17.27d±14.51d that the young and middle-aged group is in hospital days,shorter than seniors class days 23.28d±17.33d, there are significance differences on days in hospital before two groups infected(t =2.386,P =0.018).Patients before infection are at 94.09%use of antimicrobial agents, the use of three or more antibiotics has 87 cases,accounting for 42.86%.The hospital MRSA infects patient's prognosis badly,the case fatality rate is up to 27.59%.The young and middle-aged group different from prognosis of the seniors class(x~2 =10.073,P =0.006),that has not healed or died has accounted for 32.2%in the young and middle-aged group,but accounts for 56.0%in the seniors class.The prognostic situation of the seniors class is worse than young and middle-aged group.Determination of 203 MRSA to 13 kinds of antimicrobial sensitivity,sensitivity＞70%for vancomycin(100%),oxazolidine(91.6%) and rifampicin(87.2%); resistance rate＞70%for oxacillin(100%),penicillin(100%),β-lactamases(100%), erythromycin(95.6%),sultamicillin(91.6%),levofloxacin(83.7%),gentamicin (79.8%) and tetracycline(74.9%).Further analyzation of the characteristic of the hospital MRSA infection reveal that invading of operation respectively 83.7%,the others are controlled for diabetic blood glucose badly(46.3%),hypertension(42.9%), coronary heart disease(39.9%),cerebral apoplexy(34.5%),malignant tumour (32.5%),move in ICU(32.5%),hormone uses(18.2%) and liver renal failure (13.3%).Conclusions:MRSA infection rate was detected in 81.85%from Staphylococcus aureus in General Hospital in Putuo District,slightly higher than the Shanghai General Hospital of the detection rate of 80.3 percent level.The hospital MRSA infection rate is 2.68‰on average,the infection rate of ICU is the highest,should strengthen to prevent and control of MRSA in ICU.MRSA infection in hospital patients give priority to male,older(≥65 years),ICU admission and surgery, pulmonary infection and wound infection.Age median is 76 years old.Length of stay in hospital with the longest days before infection is 80 days,the shortest is 4 days,the average is 21.45d±16.72d.Patients with MRSA infection at the former,the basic broad-spectrum antibiotics are used and combined with≥3 kinds of antibiotics accounted for 42.86%.MRSA hospital infections has poor prognosis,the case fatality rate 27.59%.PartⅡ:Study of risk factors for nosocomial MRSA infectionsObjective:To explore the risk factors of nosocomial MRSA infection,in order to provide a scientific basis to take effective measures to reduce nosocomial MRSA infection rates.Methods:This study used 1:1 case-control study design.According to sample amount demand,include in 108 pairs of research objects qualified,case group stem from 203 cases of hospital MRSA infection in 2008 above-second-class general hospital, district of Putuo.The control group stems from the hospital population that are not mosocomial cases,and gender difference between the two groups of＜5%,the same hospital the same ward difference＜5%,and the case and the control group admitted to hospital date closely.Uniform questionnaire designed to study the history of case and control data to collect information.Investigate include the basic situation of patients,basic disease,in-patient days,the use of broad-spectrum antibiotic,type and time.immune damage,surgery,invasive examination and treatment;merge other multiple infections,etc.Multivariate non-conditional logistic regression and chi-square test was used to analyze the data.Results:Total collection of cases and the control of the 108 cases,single-factor analysis showed that the following factors may be associated with nosocomial MRSA infection.old age(≥65 years old,P = 0.013),length of stay in hospital(P＜0.001), the number of basic disease(P＜0.001),as well as basic diseases with poorly controlled diabetes(P＜0.001) and stroke(P = 0.005),each of invasive procedures such as surgery(P＜0.001),catheterization(P＜0.001),tracheal intubation(P＜0.001), Arterio-venous cannulation(P = 0.027),drainage(P = 0.003),stomach(P = 0.009), endoscopy(P = 0.016),ventilator(P＜0.001) as well as the number of invasive procedures(P＜0.001),with other multi-drug resistant(P＜0.001),broad-spectrum antibiotics use(P＜0.001),types of antibiotics(P = 0.004) and antibiotics use of time (P＜0.001).Multi-factor analysis showed that the main risk factors related to nosocomial MRSA infections include length of stay in hospital(P＜0.001),the number of invasive procedures(P = 0.001),antibiotic use types(P = 0.001) and antibiotic use of time(P = 0.001),etc.Conclusions:Possible risk factors of hospital MRSA infections are Length of stay in hospital longer,the number of invasive operations and more long-term use of broad-spectrum antibiotics and the use of antibiotics in many types.