Objective To investigate the characteristics of the pathogens isolated from the cerebrospinal fluid (CSF) and the prognosis of the adult patients with central venous system (CNS) infection, and to provide the basis for disease treatment. Methods The clinical data and findings of the laboratory examination of the patients, who were admitted to West China Hospital of Sichuan University from January 2014 to September 2016, and suffered from CNS infection with the positive results of CSF culture, were retrospectively analyzed. The species distribution and in-vitro susceptibility of the pathogens and hospital mortality were analyzed. Results A total of 157 cases, involving 87 (55.4%) community-acquired cases and 70 (44.6%) hospital-acquired cases, were included. One hundred and fifty-eight strains of the pathogens were isolated from the CSF specimens of these patients, including 73 isolates (46.2%) of gram negative bacteria, 64 isolates (40.5%) of fungus, and 21 isolates (13.3%) of gram positive bacteria. In terms of species distribution,Cryptococcus neoformans was the predominant (62/87, 71.3%) species isolated from the patient with community-acquired infection, whileAcinetobacter calcoaceticus-A. baumannii complex (31/71, 43.7%) was the predominant specie from the patients with hospital-acquired infection. Analysis of the resistance phenotypes showed that all theC. neoformans isolates were susceptible to the antifungal agents. More than 90% ofA. calcoaceticus- A. Baumannii complex isolates were resistant to the regular antibiotics. The resistant rates ofK. pneumoniae isolates to the regular antibiotics were no more than 25%. The hospital mortality of the groups infected by gram-negative bacteria, fungi, and gram-positive bacteria were 52.3% (38/72), 32.8% (21/64), and 19.0% (4/21), respectively. There was statistical difference for the hospital mortality among these groups (P=0.006). Conclusion In our hospital,C. neoformans are the common species isolated from CSF of the patients with community-acquired CNS infection. Gram negative bacilli are commonly isolated from CSF of the hospital-acquired cases. The mortality of patients with gram negative bacilli is high.
ObjectiveTo analyze the distribution and drug resistance of Enterobacteriaceae in West China Hospital of Sichuan University, to provide long-term monitoring data references for clinical practice.MethodsThe clinical information of non-repetitive Enterobacteriaceae isolates from 2006 to 2015 was collected and analyzed. All the isolates were identified by VITEK-2 Compact Automatic Microbial Identification Analyzer (Bio Merieux, France). The statistic informations were analyzed by WHONET 5.6 and iLabDataforMDR 1.03.ResultsA total of 38 487 strains of Enterobacteriaceae were isolated from 2006 to 2015, mainly including 14 862 stains of Escherichia (38.6%), 12 894 stains of Klebsiella (33.5%), 6 277 stains of Enterobacter (16.3%), 1 758 stains of Proteus (4.6%), 1 257 stains of Serratia (3.3%), 933 stains of Citrobacter (2.4%), and 506 stains of Morganella (1.3%). The top three sample types were sputum (46.9%), urine (18.7%), and secretions (11.5%). The drug resistance rate of Enterobacteriaceae showed a downward trend to most antibacterials. The average resistance rate of Enterobacteriaceae to ampicillin, ampicillin/sulbactam, and cefazolin was 85.3%, 52.6%, and 72.9%, respectively. The resistance rates to ceftriaxone, cefepime, gentamicin, and tobramycin were significantly reduced. The resistance rates to other antibiotics showed decreasing or slow increasing trends. The isolation rate of extended-spectrum β-lactamases (ESBL)-producing strains in Escherichia did not change, but the rate in Klebsiella decreased significantly. The isolation rate of multidrug-resistant organisms (MDRO) showed a slow decrease.ConclusionsThe overall antimicrobial resistance and the isolation rates of MDRO and ESBL-producing organisms showed a downward trend in investigating period. However, the carbapenem-resistant Enterobacteriaceae was rising continuously. Long-term monitoring of drug resistance is of notable value to antibiotic management policies.
ObjectiveTo understand the drug resistance of Mycobacterium tuberculosis complex in West China Hospital, Sichuan University, analyze its drug resistance characteristics, and provide reference for the monitoring of drug-resistant tuberculosis.MethodsFrom January 2016 to March 2018, Mycobacterium tuberculosis drug susceptibility testing kit was used to detect the drug susceptibility of Mycobacterium tuberculosis culture-positive strains in Department of Laboratory Medicine, West China Hospital, Sichuan University. The tested drugs included four of the first-line anti-tuberculosis drugs: rifampicin, isoniazid, ethambutol, and streptomycin, and ten of the second-line anti-tuberculosis drugs: capreomycin, ofloxacin, ethionamide, p-aminosalicylic acid, levofloxacin, moxifloxacin, rifabutin, amikacin, kanamycin, and chlorine phenazine.ResultsA total of 130 patients (130 strains) were enrolled, including 82 newly diagnosed patients (82 strains) and 48 re-treated patients (42 strains). The drug resistance rate of the 130 patients was 37.69%. The drug resistance rate of the newly diagnosed patients (28.05%) was significantly lower than that of the re-treated patients (54.17%), and there was a statistical difference (χ2=8.794, P=0.003). The multi-drug resistance rate of the newly diagnosed patients (6.10%) was significantly lower than that of the re-treated patients (25.00%), and the difference was statistically significant (χ2=9.517, P=0.002). The resistance rate of isoniazid, rifampicin, and streptomycin in newly diagnosed patients (23.17%, 8.54%, and 7.32%, respectively) were significantly lower than those in the re-treated patients (45.83%, 41.67%, and 29.17%, respectively), and the differences were statistically significant (P<0.05). The resistance rate of ofloxacin, moxifloxacin, rifabutin and ethionamide in the newly diagnosed patients (9.76%, 8.54%, 7.31%, and 4.88%, respectively) were significantly lower than those in the re-treated patients (39.58%, 27.08%, 25.00%, and 22.92%, respectively), and the differences were statistically significant (P<0.05).ConclusionIt is necessary to strengthen the standardized treatment of patients with newly diagnosed tuberculosis, increase the treatment and management of re-treated tuberculosis patients, and prevent the generation and spread of drug-resistant patients, especially multidrug-resistant patients.
ObjectiveTo evaluate the accuracy and practicability of matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) in clinical isolates of mycobacteria.MethodsWe collected all tested strains, which were positive for Mycobacterium tuberculosis culture and positive for acid-fast staining, from West China Hospital of Sichuan University from 2014 to 2017, eliminating duplicate strains sent by the same patient at the same time. The traditional method was used with the P-nitrobenzoic acid (PNB)/ 2-Thiophenecarboxylic acid hydrazide (TCH) indicator to initially identify acid-resistant positive strains. Mycobacteria was identified by MALDI-TOF MS; the specificity and sensitivity of the MALDI-TOF MS was analyzed by duplex primer-polymerase chain reaction (Duplex-PCR) method and DNA sequencing method as the "gold standard" for the identification.ResultsA total of 237 anti-acid positive strains were collected; Mycobacterium tuberculosis complex (MTC) and non-tuberculous mycobacteria (NTM) were identified by mycobacterium double primer PCR, and NTM was identified by 16S rRNA gene sequencing. There were 218 cases of MTC and 19 cases of NTM. The results of preliminary identification using the traditional identification method of PNB/TCH indicator showed that there were 209 cases of MTC (with the sensitivity of 95.9%, specificity of 100.0%, positive predictive value of 100.0%, and negative predictive value of 67.9%) and 28 cases of NTM (with the sensitivity of 100.0%, specificity of 95.9%, positive predictive value of 67.9%, and negative predictive value of 100.0%). The results of MALDI-TOF MS method indicated that there were 199 cases of MTC (with the sensitivity of 91.3%, specificity of 100.0%, positive predictive value of 100.0%, and negative predictive value of 50.0%), 32 cases of NTM (with the sensitivity of 68.4%. specificity of 94.0%, positive predictive value of 40.6%, and negative predictive value of 97.1%), and 6 cases of others. There were 168 strains (84.4%) with the identification score>1.9 obtained by MALDI-TOF MS method.ConclusionsMALDI-TOF MS is a better method for identifying mycobacteria, which has the same identification results as the traditional methods, and has low cost and is suitable for routine use in clinical microbiology laboratories.