After theLushan earthquake, the Chinese government and various departments responded quickly. Theemergency response plans were immediatelyactivated. The experts in intensive care, orthopedics, neurosurgery, thoracic surgery, infectious disease, nephrology, clinical pharmacology and rehabilitation from west China hospital and across China assessed patients' condition and made clinical treatment strategies together daily. The condition of severe wounded were reported twice a day.
Methods
The study was approved by the Ethics Committee of West China Hospital, Sichuan University, which waived the need for informed consent, as all the data and samples were collected as part of normal care in daily clinical practice, according to the current guidelines.
We retrospectively reviewed the medical records of the 81 critical patients. All data were verified by two authors independently.
Clinical specimens were obtained from blood, sputum, wound, urine, stool, intravenous and intraurethral catheters in patients with fever or signs of infections. All samples were collected under sterile conditions and blood samples were collected in more than two sets of aerobic and anaerobic. Bacterial identification and minimal inhibitory concentrations (MICs) of antibacterial agents against bacteria were performed by the VITEK-2 COMPACT automated microbiology system (BioMerieux). The antimicrobial susceptibility results were interpreted according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Patients had definitive diagnoses of infection complications according to medical history, clinical findings, laboratory and imaging tests.
Stringent infection control measures were implemented to preventhospitalinfections. First, entry into ICU wasrestricted including visitation, thenumberof health workers and hospital cleaners, placement of obvious warnings near the bed units, improvements inhand hygienecompliance, the use of disposable gloves, masks and caps, increase the number of disinfection of surroundings. Enhanced antimicrobial stewardship including the choice of antibiotic and dosage regimen were introduced. Based on consideration of the patient's clinical course, procalcitonin (PCT) was used for early diagnosis, monitoringof treatment responses to reduce inappropriate use of antibiotics [1].
Before admissiontoICU, somepatients were treated with active surgical procedures such as craniotomy, debridement, fasciotomy and amputation. The treatments ofdrainage subarachnoid lumbar space continuously were appliedto the patients with severe craniocerebral trauma after craniotomy. The treatments of vacuum sealing drainage dressing (VSD) were appliedto the patients with open fractures of extremities withskin andsoft tissuedefectafter surgery. Wound dressings were changed daily or twicea day according tosituationofpatients. Some patients were received the secondoperationfor removal of the infected foci to improve infection control.
Statistical analysis: Data were analyzed by SPSS version 17.0 software package. A normality test was performed for all quantitative variables. Continuous variables with normal distributions were presented as mean±standard deviation. The comparison of group differences for continuous variables was performed using Student’s t-test and one-way ANOVA. LSD-t test was used for multiple comparison. A two-tailed P < 0.05 was considered statistically significant.
Results
Clinical characteristics of 81 critically ill patients with earthquake related trauma
A total of 81 critically ill patients (mean age: 54.83 ± 25.13 yr; 47 male) were included in the study. Children younger than 16 years accounted for 7.4% and those older than 80 years accounted for 24.7% of the patients. APACHE II(Acute Physiology and Chronic Health Evaluation II) and Sequential Organ Failure Assessment (SOFA) [2] were applied within 24 hours of admission of each patient to our ICU. There were significant differences in the scores of APACHE IIand SOFA among different causes of injury groups (P < 0.01).
Infections
A 14.81% proportion of the trauma patients had no infection and 85.19% (69/81) had infectious complication during staying in ICU. There were 59 cases of community acquired infections when admission to ICU, however, 5 of whom (8.47%, 5/59) had nosocomial infections when leaving the ICU. Elevencasessuffered from multi-site infections.
A total of 421 clinical specimens were collected. Pathogens identified from 69 hospitalized patients with infections were shown in Table S1. Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa were the most frequent pathogens isolated from patients with nosocomial infections, and the most frequently isolated pathogen from patients with community acquired infections was Staphylococcus aureus. There were 54 cases with positive culture results. Infectionscaused bygram-negative bacteria (34/54, 63.0%) were morecommon, predominantly Klebsiella pneumoniae (24.1%, 13/54), followed by Acinetobacter baumannii (20.4%, 11/54). Gram-positive bacteria caused 37.0% (20/54) of infections, predominantly Staphylococcus aureus (6/54, 11.1%) and Staphylococcus epidermidis (9.3%, 5/54). Mixedinfections were present in12episodes.
Antimicrobial drug susceptibility testing results for the 5 most common pathogens were shown in Table S2. All the Staphylococcus aureus were sensitive to vancomycin and tigecycline, followed by rifampicin, oxacillin and clindamycin. Most of Acinetobacter baumannii were multiresistant strains, which sensitive to polymix and resistant to other antibacterial drugs in varying degrees. It was worth noting that the resistance of Acinetobacter baumannii toimipenemwas88.2%. The candida albicans was sensitiveto amphotericinB, fluconazole, itraconazole and 5-fluorocytosine.
Outcomes
Noneof the81 patientsincluded in this study died during the hospital stay. One patient automaticallydischarged forpersonalreasons inthe fifth dayafter admission. He suffered seriouscraniocerebralinjury and receivedcardiopulmonaryresuscitation before admission toICU. Three patients withunderlyingdiseases discharged voluntarily because the general condition of them graduallydeteriorated. The rest of the patients survived with positive outcomes.
Discussion
Earthquake is the most harmful natural disasters because it can cause heavy casualties and property losses. China is an earthquake-prone nation. The 1976 Tangshan earthquake resulted in more than 240 000 deaths and 165 000 injuries, the 2008 Wenchuan earthquake caused more than 69000 deaths and 374000 injuries. People had suffered severeinjury in theearthquake, thesubsequent increasing in infectious complication has a major impact on patient outcomes [3]. Many factors can cause infection in earthquake victims include open wounds, insufficient wound debridement, invasive procedures, use of venous and urinary catheters, the functional disorders of immunesystem, etc.
The patients in our ICU all had severemultipletrauma, the most common types of injury were bone fractures, craniocerebral injuries, and chest injuries, which was similar to the results of theepidemiological investigation of this earthquake and the previous earthquakes [4-6]. Crushing injuries were more serious than damages from other causes in this study. Previousstudies have alsofound that severe crushing injury was morelikely tohave complications andresulted in death [7,8]. There were less crush injury patients, and only one of them had crushsyndrome. It was possible that because the earthquake occurred in theremotearea and no tall buildingscollapsed, timely and effectively emergency rescue based on experiences and lessons of Wenchuan earthquake. Thatwas may beone reason that the critical ill patients in our ICU had better clinical outcome.
Similartopreviousreports [4,9-10], pulmonary infection was the most common infectious complication in the patients. The high incidence of pulmonary infections after the earthquake mightbe related to overcrowding and the severe damage in infrastructure and health-care systems. Intracranial infection was another common infectious complication in patients in our ICU. Craniotomy, most of the severe craniocerebral trauma patients in ICU underwentit, immune function constantly disorder after severe injuries and continuous terminal cistern drainage might be thereasons for high susceptibility to craniocerebral infection.
Acinetobacter baumannii and Klebsiella pneumoniae were themajorpathogens. They also were common isolates in our hospital. All severely injured patients were transported from the earthquake zone, some patients were treated with surgical procedures and received antimicrobial agents in local hospital with poor conditions and the absence of essential surgical equipment and infection control measures, necessaryinvasive procedures such as venous catheter, tracheal intubation, indwelling catheter were performed in some patients. The above factors might cause nosocomial diseases.
Only one patient complicated with fungal infection, which were lessthan previously reported [11]. Thefungiwere accounted for 9.7%of the isolated pathogens from the victims in the 2008 Wenchuan earthquake [12]. Many factors might be related to the lower incidence of fungal infection in the patients, such as enhanced antimicrobial stewardship, strict infection control measures and aggressive immune supportive treatment.
Noneof the patients in ICU died during the hospital stay. We summarized some experiences with infection control in Lushan earthquake injuries. First, empiric antimicrobial drugs selection were based on infection sites, thepossible pathogens, pathogens spectrum of the hospital, etc. It is important to change effective antibiotics to control infection in a timely manner according to the patient's clinical course and the microbiological data. Second, PCT was used to guide the use of antimicrobials. Because many studies had shown that PCT had abilities to early detect bacterial infection and assess the clinical efficacy of the empirical antibiotic therapy [13-14]. Third, Meropenem (2 g every 8 hour) was given when intracranial infections were diagnosed following Infectious Disease Society ofAmerican(IDSA) guidelines [15]. Fosfomycin has maintained its bactericidal activity against anaerobic pathgeons, many gram-positive, gram-negative bacterial and multi-resistant pathogens over the years. Inaddition, fosfomycin has minimal side effects and it can act as an immunomodulator and protect human cells fromcertainmedications'toxicities [16-17]. Therefore, the combined treatment with fosfomycin and other antibacterial agents were used to treat infectionscaused by MDR pathogens. Fourth, targeted immune-enhancing therapy was very important for patients with serious infections. Studies suggested that multiple immune defects occur insepsis, immune-enhancing therapy such as thymosin alpha 1, immunoglobulins, granulocyte macrophage colony stimulating factor can improvethe prognosis [18-21]. Fifth, Stringent infection control measures were implemented to prevent the spread of infection. Our hospital managers often use multimodal strategies to raise the theconsciousness of infection prevention and control among different grades of staff, such as administrative support, motivation, free availability of hand disinfectants, training and intensive education of medical workers. Therefore, we are already usedto carry out control infection measures. And our hospital won the Asia Pacific Hand Hygiene Excellence Award (2012/2013).
Table S1. Pathogens identified from 69 hospitalized patients with infections
Pathogens / Infection sitesWound secretion / blood / Respiratory secretion / urine / Cerebrospinal fluid / stool / Total(%)
Acinetobacter baumannii / 13 / 3 / 25 / 4 / 6 / - / 51(38.1)
Klebsiella pneumoniae / 7 / 1 / 16 / 3 / 1 / - / 28(20.9)
Pseudomonas aeruginosa / 4 / 8 / 1 / - / - / 13(9.7)
Escherichia coli / 5 / 3 / 1 / 2 / - / - / 11(8.2)
Enterobacter cloacae / 1 / 1 / - / 1 / - / - / 3(2.2)
Burkholderia cepacia / - / - / 1 / - / - / - / 1(0.7)
proteusmirabilis / - / - / 1 / - / - / 1(0.7)
Staphylococcus aureus / 7 / - / 1 / - / - / - / 8(6.0)
Staphylococcushaemolyticus / 5 / 2 / - / - / - / - / 7(5.2)
Enterococcusfaecium / 2 / 1 / - / - / 1 / - / 4(3.0)
Streptococcus pneumoniae / - / - / 1 / - / - / - / 1(0.7)
Staphylococcusepidermidis / 1 / - / - / - / - / - / 1(0.7)
Candidaalbicans / - / - / 2 / 3 / - / - / 5(3.7)
Total (%) / 45(33.6) / 11(8.2) / 56(41.8) / 14(10.4) / 8(6.0) / - / 134
“-” means that bacteria were not found in the cultures.
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Table S2. Antimicrobial susceptibility of the 5 most common pathogens isolated from patients injured during earthquake, Lushan, China, 2013
Organism / No. (%) the resistance ofpathogens to antibacterialsNo. / IMP / MEM / TZP / AMP / ZOX / AMK / AZT / CAZ / SAM / FEP / PB / CIP / SMZ / GM / LEV / TGC / DA / OX / RD / VA
A. baumannii / 51 / 45(88.2) / 48(94.1) / 47(92.2) / 51(100) / 51(100) / 45(88.2) / 50(98.0) / 45(88.2) / 33(64.7) / 47(92.2) / 0(0) / 48(94.1) / 36(70.6) / 48(94.1) / 21(41.2) / 4(7.8) / - / - / - / -
K.pneumoniae / 28 / 0(0) / 0(0) / 1(3.5) / 28(100) / 18(64.3) / 13(46.4) / 15(53.6) / 15(53.6) / 2(7.1) / 13(46.4) / 0(0) / 13(46.4) / 5(17.9) / 5(17.9) / 13(46.4) / 0(0) / - / - / - / -
P. aeruginosa / 13 / 6(46.2) / 6(46.2) / 1(7.7) / 13(100) / 12(92.3) / 0(0) / 8(61.5) / 1(7.7) / 0(0) / 0(0) / 0(0) / 0(0) / 1(7.7) / 0(0) / 0(0) / 0(0) / - / - / - / -
E.coli / 11 / 0(0) / 0(0) / 0(0) / 6(54.5) / 6(54.5) / 0(0) / 5(45.5) / 3(27.3) / 0(0) / 3(27.3) / 0(0) / 0(0) / 2(18.2) / 2(18.2) / 0(0) / 0(0) / - / - / - / -
S. aureus / 8 / - / - / - / - / - / - / - / - / - / - / - / 2(25) / 2(25) / 4(50.0) / 2(25.0) / 0(0) / 6(75) / 4(50) / 2(25) / 0(0)
S.haemolyticus / 7 / - / - / - / - / - / - / - / - / - / - / - / 6(85.7) / 3(42.9) / 6(85.7) / 6(85.7) / 0(0) / 5(71.4) / 7(100) / 1(14.3) / 0(0)
MEM, Meropenem; TZP, tazobactam/piperacillin; AMP, ampicillin; ZOX, ceftizoxime; AMK, amikacin; AZT, Aztreonam; CAZ, Ceftazidime; SAM, Cefperazone-Sulbactam; FEP, Cefepime; PB, polymyxin B; CIP, ciprofloxacin; SMZ, sulfamethoxazole/trimethoprim; GM, gentamicin; LEV, levofloxacin; TGC, Tigecycline; DA, clindamycin; OX, Oxacillin; RD, rifampicin; VA, vancomycin; A. baumannii, Acinetobacter baumannii; P. aeruginosa, Pseudomonas aeruginosa; K. pneumoniae, Klebsiella pneumoniae; E.coli, Escherichia coli; S. aureus, Staphylococcus aureus; S.haemolyticus, Staphylococcushaemolyticus.
“-”, not available.
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