Transmission Dynamics And Monitoring Of Multi-drug-resistant Bacteria Colonization And Infection In A SICU

Nosocomial infection had became a worldwide major public health problem, patients with high infection and mortality rate were seriously affected the development of medical standards and gived a heavy burden on families and society. As the abuse and misuse of antibiotics was prevalent, and nosocomial infection characteristics of multi-drug resistant pathogens present, treatment was even more difficult, therefore, prevention and control of nosocomial infection prevalence became particularly necessary. ICU was a high incidence of nosocomial infection departments, methicillin-resistant Staphylococcus aureus and multi-drug resistant Acinetobacter baumannii infections were caused by the incidence of nosocomial infection in the first place. Monitoring colonization and infection of MRSA and MRAB in the SICU, related risk factors analysised , combined with the transmission dynamics parameters and status research of infection control measures (hand hygiene of medical personnel) , in-depth analysis of the key factors about the spread of MRSA and MRAB in this SICU, in order to better prevention and control prevalence of multi-resistant nosocomial infection pathogen, filling research gaps, promoted the nosocomial infection epidemiology to the rapid development of new research directions.Objective:To monitor the prevalence of meticillin-resistance Staphylococcus aureus (MRSA) and multi-drug-resistance Acinetobacter banmannii(MRAB) , antibiotics resistance status,;to analyze the risk factors of colonization and infection; to analyze the transmission dynamics study of important parameters and medical personnel hand hygiene status, determine the impact key factors of multi-drug-resistant bacteria in ICU.Methods:(1)Monitoring the colonization and infectionThe inpatients and healthcare workers in a surgical intensive care unit (SICU) were investigated the colonization and infection of MRSA and MRAB. Patients were screened for MRSA or MRAB colonization within the first 48h of admission and once within two days thereafter, with swab samples taken from the anterior nares, forehead, groins, axillae. In the same period, swab samples taken from the anterior nares of health care workers were obtained at least once monthly, and the propotion of contacts resulting in the hands of health care workers were obtained once within two days, they were collected and also served as screening cultures for MRSA and MRAB. Swab samples collected from the environments nearby patients and work section (e.g., handrail of beds, buttons of equipment, bed sheets, bed table, observation tables and books of nurse, water taps, calculators, tables used to fill prescriptions) were obtained once within four days and also served as screening cultures for MRSA and MRAB. Screening swabs and propotion of all respiratory specimens were inoculated on blood plates and then incubated overnight at 37°C.The resemble colonies of MRSA were identified by presence of protein A, fibrinogen receptor, coagulase and CHROMagar Staph aureus(CSA). The resemble colonies of MRAB were identified by the typical colonies on the blood Plate, 42°C growth, the typical colonies on the China-Blue medium , Triple Sugar Iron Agar and Citrate agar ,seven types of antibiotic susceptibility test (three or more drug-resistant).The seven types of antibiotic is Cefuroxime , Cefepime . Cefotaxime , Imipenem , Amikacin , Minocycline and Levofloxacin .Risk factor(e,g, age, sex, underlying conditions, reason for admission, urgency of admission, previous hospitalization and origin of referral, immediate unit within the hospital before the ICU, time and place of intubations, Acute Physiology and Chronic Health Evaluation (APACHE) II score at 24h, Glasgow coma score, number of organs that would fail without mechanical or pharmacologic support, duration and type of intubations) analysis included univariate and multivariate approaches.(2) Investigation of parameters describing strength of transmissionThe parameters used were based on daily data collection and direct observation of staff-patient contact patterns. Observed parameters for each monthly interval were admission and discharge rates of colonized and noncolonized patients and average staff numbers. The proportion of staff who did not contribute to transmission, which was equivalent to the cohorting probability, q, the staff-patient contact rate, the probability of hand washing/disinfection, the probabilities of transmission from patient to staff were obtained from investigantion. The possible role of environmentalfactors was analyzed.Results:1) ICU moved to a new environment at July 15th 2008, the environment, management and staffs were changed largely.2) From April 2008 to January 2009.301 patients (admission after 48h) were treated in the ICU during the investigation period. MRSA was colonized from 39 patients, the ratio of colonization is 13.0%.The numbers of patients infected by MRSA is 11, the ratio of infection is 3.7%, the ratio of MRSA positive (colonization/infection) is 13.6%, the ratio of after admission of MRSA positive is 7.6%.MRAB was colonized from 104 patients, the ratio of colonization is 34.6%.The numbers of patients infected by MRSA is 43, the ratio of infection is 14.3%, the ratio of MRSA positive (colonization/infection) is 33.6%, the ratio of after admission of MRSA positive is 28.2%. The prevalence of MRSA was highest at June and declined after, at same time, the prevalence of MRAB keep higher in old ward and lower in new ward. The detection ratio of nasal fossa was highest and stationary in the patients' specimens. The detection raito of staffs' hand was higher than nasal fossa, MRSA is 8.88% and MRAB is 11.15%. The specimens of environments were identified of MRSA and MRAB, the ratio of bed sheets, handrail of beds and observation tables of nurses' were higher than others.3) The MRAB resistance status was very seriously, the isolation rate of MRAB was 79.6%, PRAB was37.1%, the isolation rate of patient specimens increased significantly in the new ward and resistance to change with great speed. The resistance to imipenem and minocycline were significantly increased.4) The contamination of water taps was significantly correlated to MRAB co colonization and infection after admission.5) The results of the risk factor analysis, Periods of staying in ICU, Intubations, the kind of Surgery( acute or choosing times), Using third-generation cephalosporins, Using second-generation cephalosporins, Using peptidoglycan and Types of antibiotic were correlated to MRSA colonization and MRAB conlonization or infection, In addition, APCHEII score at 24h, type of nutrition, Times of exchanging beds. Surgical trauma, Surgery, Using Quinolone, Using carbapenems, Using semisynthetic penicillin and Using aminoside were correlated to MRAB colonization or infection. Periods of staying in ICU was a common independent risk factor .intubations before admission and Using second-generation cephalosporins were only independent factors of MRSA,but APCHEII score at 24h, Using third-generation cephalosporins. Using peptidoglycan and Surgery were independent factors of MRAB.6) ICU staying .Duration of intubations after admission, times of Surgery, Using third-generation cephalosporins, peptidoglycan, carbapenems and antibiotic of anti-fungus were correlated to MRSA and MRAB positive after admission, In addition. Times of exchanging beds, types of antibiotics, Quinolone, semisynthetic penicillin and aminoside were only correlated to MRAB. Periods of staying in ICU and mix nutition were independent risk factors to MRSA and MRAB positive after admission, besides. Times of exchanging beds, aminosid and antibiotics of anti-fungus were only independent risk factors to MRAB.7) contact rate was 3.55 (old ward) and 1.6 (new ward), contact rate of every stuffs was 7.1 (old ward) and 2.7 (new ward), contact between stuffs and environment around patients was 2.4.8) The value of bs_MRSA was 0.179, bs_MRAB was 0.154.9) cohort probability (q) . was close to the positive after admission of multi-resistant bacteria, In November, q was highest, at same time, the prevalence of MRSA and MRAB were lowest , in June ,q was lowest, at same time, the prevalence of MRSA and MRAB were highest10) In June, the prevalence of MRSA and MRAB after admission was highest,μ_MRSA andμ_MRAB were lowest, but in November, the prevalence MRSA and MRAB after admission were lowest, two values were in the peak of the new wards and close to positive patients after admission.11) The trends of ratio curve of Np and Ns were different with the trend of positive patients after admission.12) The total average compliant rate of hand hygiene is 27.8%. the compliant rate between different objects was no statistical Significance. The compliant rate of before contact patients was highest, 44.9% and incidence rate was also highest, 66.2%. after contact patients and after contact articles related with patients were very low(10.6% and 11.7%).The compliant rate of nurses under all indicators were significantly higher than doctors, the methods of compliant were significant different, the methods of before contact patients was using gloves, after contact patients was using ABHR, the using rate of doctors was significantly higher than nurses. In low-pollution hazards, the compliant rate of contact steriles was highest .44.6%, in high-pollution hazards, the compliant rate of contact faeces and comtaminated by faeces were higner , 84.6% and 76.9%, while the contact with skin , wound, intravenous injection and so on, the compliant rate of hand hygiene were lower ,only 40%.Conclusion:Monitoring colonization of patients, stuffs and environment, appropriate isolation to bring positive patients, strengthen the protection of susceptible populations, shorten ICU stay time, reducing the number of transfer bed , reducing intubation and durations, adjusting the medication practices of doctors, in particular, reducing the using of cephalosporins, aminoglycosides and anti-fungal antibiotic, strengthening the promotion and supervision ompliant rate of hand hygiene, providing a reasonable number of stuffs , strict 1:1 of patient to stuffs who took care of patients directly and strengthening of environmental disinfection . Developing a comprehensive infection control measures were effective in reducing the colonization or infections of multiple drug-resistant bacterias.