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.
Objective To analyze the characteristics of pathogens causing bloodstream infection (BSI) after cardiovascular surgery, and provide instructions for prevention and treatment of such kind of disease. Methods A retrospective investigation of clinical and pathogenic data of the patients suffering from BSI after cardiovascular surgery in West China Hospital of Sichuan University from January 2015 to December 2016 was performed. There were 61 patients with 36 males and 25 females at average age of 48.2±17.1 years. A percentage of 65.6% (40/61) of the underlying diseases was rheumatic heart disease. Results Sixty-five strains were isolated from the blood culture specimens of the 61 patients. Gram-positive bacteria, gram-negative bacteria and fungi isolates accounted for 56.9% (37/65), 35.4% (23/65), and 7.7% (5/65), respectively. Among these isolates, Streptococcus spp. was predominant (19/65, 29.2%), followed by Staphylococcus epidermidis (8/65, 12.3%), Staphylococcus aureus (6/65, 9.2%), Acinetobacter calcoaceticus- A. baumannii (5/65, 7.7%) and Escherichia coli (5/65, 7.7%). The resistance rate of Streptococcus spp. to erythromycin and clindamycin was 73.4% (14/19) and 63.2% (12/19), while its resistance to cefepime, vancomycin or linezolid was not observed. Staphylococcus spp. showed the resistance rate of 71.4% (10/14) to oxacillin. All of A. calcoaceticus-A. baumannii isolates were multidrug resistant (5/5, 100.0%), and 80.0% (4/5) of them were resistant to imipenem. The isolates producing extended spectrum beta-lactamase accounted for 80.0% (4/5) of E. coli. Conclusion Streptococcus spp. was the common pathogen causing BSI after cardiovascular surgery. Staphylococcus spp. and gram-negative bacilli show high resistance.
Objective To investigate the characteristics of the pathogens causing bloodstream infection after general surgery in infant and young children patients, and to provide the references for disease treatment and nosocomial infection control. Methods The clinical and laboratory examination data after general surgery in infant and young children patients, who were admitted to our hospital from January 2012 to March 2017, were retrospectively collected. The pathogens and drug resistance were analyzed by SPSS 18.0 software. Results In this study, 109 cases were included, and 117 strains of the pathogens were isolated, including 53 isolates (45.3%) of gram negative bacteria, 41 isolates (35.0%) of gram positive bacteria, and 23 isolates (19.7%) of fungi. Escherichia coli (16/117, 13.7%), Enterococcus faecium (13/117, 11.1%), Candida parapsilosis (12/117, 10.3%), Klebsiella pneumoniae (9/117, 7.7%) and Enterococcus faecalis (8/117, 6.8%) were the top 5 species. Strains producing extended-spectrum beta-lactamase accounted for 87.5% of E. coli (14/16) and 44.4% (4/9) of K. pneumoniae isolates. Both E. faecium and E. faecalis were susceptible to vancomycin. C. parapsilosis showed the susceptibility to the antifungal agents. Conclusion Gram negative bacteria are predominant pathogens causing bloodstream infection after general surgery in infant and young children patients, and infection caused by resistant isolates should be prevented and controlled.
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 analyze the diagnostic efficacy of colloidal gold immunochromatography assay (GICA) in detection of SARS-CoV-2.MethodsUsing GICA detection kits from three different manufacturers, 33 serum samples were collected from 12 patients with SARS-CoV-2 infection at different time and 45 serum samples from 45 patients without SARS-CoV-2 infection were collected from West China Hospital of Sichuan University from January to February, 2020.ResultsThe sensitivity, specificity, positive predictive value and negative predictive value of the three GICA reagents were 66.7% - 90.9%, 73.3% - 100.0%, 71.4% - 100.0% and 80.4% - 91.7% respectively. The rates of missed diagnosis and misdiagnosis were 9.1% - 33.3% and 0 - 26.7%, respectively. The positive rate decreased with titer increasing. The interference factors mainly included human immunodeficiency virus infection, high rheumatoid factor blood samples, and hemolysis.ConclusionClinical laboratories should pay attention to the differences in the detection ability and potential cross-reaction of different reagents, or use a combination of multiple antibodies.
ObjectiveTo investigate the diagnostic value of lateral chromatography for cryptococcal capsular polysaccharide antigen in cryptococcal infection.MethodsThe data of patients who detected cryptococcal capsular polysaccharide antigen in West China Hospital of Sichuan University in 2018 were collected. The sensitivity, specificity, positive predictive value and negative predictive value of cryptococcal capsular polysaccharide antigen detected by lateral chromatography were analyzed. The samples with positive lateral chromatography and definite clinical diagnosis were compared with the results of ink staining and fungal culture.ResultsA total of 721 cases were detected. The sensitivity, specificity, positive predictive value and negative predictive value of lateral chromatography detection were 100.00%, 99.39%, 93.93%, 100.00%, respectively. The positive rates of ink staining, fungal culture and cryptococcal capsular polysaccharide antigen for cryptococcal infection were 63.46%, 48.00% and 100.00%, respectively. Sixty-two patients were clinically diagnosed, including 45 cases of cryptococcal meningitis (72.58%), 16 cases of cryptococcal pneumonia (25.81%), and 1 case of bone cryptococcal infection (1.61%).ConclusionsLateral chromatography detection for cryptococcal capsular polysaccharide antigen shows well performing sensitivity and specificity in the diagnosis of cryptococcal infection. Considering its rapid and simple pre-operation, cryptococcal capsular polysaccharide antigen detection with lateral chromatography has good application value for early diagosis of cryptococcal infection.
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.