[Show abstract][Hide abstract] ABSTRACT: Staphylococcus aureus (S. aureus) remains as an important microbial pathogen resulting in community and nosocomial acquired infections with significant morbidity and mortality. Few reports for S. aureus in lower respiratory tract infections (LRTIs) have been documented. The aim of this study was to explore the molecular epidemiology of S. aureus in LRTIs in China.
A multicenter study of the molecular epidemiology of S. aureus in LRTIs was conducted in 21 hospitals in Beijing, Shanghai and twelve other provinces from November 2007 to February 2009. All the collected S. aureus strains were classified as minimum inhibitory concentration (MIC), mecA gene, virulence genes Panton-Valentine Leukocidin (PVL) and γ-hemolysin (hlg), staphylococcal cassette chromosome mec (SCCmec) type, agr type, and Multilocus Sequence Typing (MLST).
Totally, nine methicillin-sensitive S. aureus (MSSA) and 29 methicillin-resistant S. aureus (MRSA) strains were isolated after culture from a total of 2829 sputums or bronchoalveolar lavages. The majority of MRSA strains (22/29) had a MIC value of ≥ 512 µg/ml for cefoxitin. The mecA gene acting as the conservative gene was carried by all MRSA strains. PVL genes were detected in only one S. aureus strain (2.63%, 1/38). The hlg gene was detected in almost the all S. aureus (100% in MSSA and 96.56% in MRSA strains). About 75.86% of MRSA strains carried SCCmec III. Agr type 1 was predominant (78.95%) among the identified three agr types (agr types 1, 2, and 3). Totally, ten sequence type (ST) of S. aureus strains were detected. A new sequence type (ST1445) was found besides confirming ST239 as the major sequence type (60.53%). A dendrogram generated from our own MLST database showed all the bootstrap values ≤ 50%.
Our preliminary epidemiology data show SCCmec III, ST239 and agr type 1 of S. aureus as the predominant strains in LRTIs in Mainland of China.
Preview · Article · Mar 2011 · Chinese medical journal
[Show abstract][Hide abstract] ABSTRACT: To investigate the pathogens, clinical manifestations, prognosis of and the risk factors for pulmonary mycosis in China.
All cases of pulmonary mycosis from 16 centers in 10 cities from Jan. 1998 to Dec. 2007 that met the diagnostic criteria were included for clinical, microbiological and radiological analysis.
Totally 474 cases of pulmonary mycosis were retrieved. The top 5 pulmonary mycosis was pulmonary aspergillosis (180 cases, 37.9%), pulmonary candidiasis (162 cases, 34.2%), pulmonary cryptococcosis (74 cases, 15.6%), pneumocystis carinii pneumonia (23 cases, 4.8%) and pulmonary mucormycosis (10 cases, 2.1%). The constituent ratio in the last 3 years was similar to that in the former 7 years. The main pathogens of pulmonary candidiasis were Candida albicans (308/474, 65.0%) and Candida tropicalis (57/474, 12.0%), which were sensitive to common azoles. Compared with bacterial pneumonia, pulmonary mycosis showed more symptoms of hemoptysis (147/474, 31.0%) and pleural effusion (95/474, 20.0%), and less radiological specificity. Classical halo sign (4/474, 0.8%) and crescentic sign (17/474, 3.6%) were only shown in several cases of pulmonary mycosis. The most common underlying diseases were tumor (including solid tumor and malignant hematological diseases) (94/474, 19.8%), chronic obstructive pulmonary disease (52/474, 11.0%), pulmonary tuberculosis (50/474, 10.5%) and diabetes (48/474, 10.1%). Compared with the other common pulmonary mycosis, pulmonary cryptococcosis affected younger patients, and more cases were community-acquired, but fewer cases with underlining diseases or compromised immune function, and had a better prognosis.
The ahead five species of pulmonary mycosis in China were orderly pulmonary aspergillosis, pulmonary candidosis, pulmonary cryptococcosis, pneumocystis carinii pneumonia and pulmonary mucormycosis. The main pathogens of pulmonary candidosis were Candida albicans and Candida tropicalis, which were sensitive to common azoles. Compared with the other common pulmonary mycosis, pulmonary cryptococcosis catch younger patients, had more community-acquired cases, and had better prognosis.
No preview · Article · Feb 2011 · Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases
[Show abstract][Hide abstract] ABSTRACT: To investigate the current status of atypical pathogen associated infections in community-acquired pneumonia (CAP) in adults, and their clinical attributes.
Clinical data, sputum specimens from acute phase, and paired sera from acute- and convalescent-phases of CAP in 153 adult patients were collected from May 2005 to May 2008 in multiple medical centers. Chlamydia pneumoniae (Cpn) IgG antibody, and Legionella pneumophila (LP) mixed IgG, IgA and IgM antibodies were determined by indirect immuno-fluorescent assay. Mycoplasma pneumoniae (Mpn) mixed IgG, IgA and IgM antibodies were determined by passive agglutination assay. All the sputum specimens were routinely cultured for bacterial isolation.
Fifty-two (34%) out of the 153 cases were diagnosed as atypical CAP per the paired serum-antibody assay. Forty-seven of the 52 atypical CAP cases were infected by one atypical pathogen, 38 with Cpn, 4 with Mpn, and 5 with LP, while 5 out of the 52 atypical CAP cases were infected by 2 pathogens, Cpn and Mpnin 2, Cpn and LP in 3 cases. Eleven cases (21.2%) out of the 52 patients with atypical pneumonia were complicated with bacterial infection. Except peripheral white blood count was significant increased in the group of typical (bacterial only) pneumonia (WBC > 10 × 10⁹)/L, P = 0.03), all the other clinical parameters did not show statistically significant difference between the typical and the atypical pneumonia groups.
Our data suggest that Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila are common pathogens of adult CAP. Chlamydia pneumoniae might be the most frequent atypical pathogen associated with atypical CAP.
No preview · Article · Sep 2010 · Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases
[Show abstract][Hide abstract] ABSTRACT: Acinetobacter baumanii (A. baumanii ) remains an important microbial pathogen resulting in nosocomial acquired infections with significant morbidity and mortality. The mechanism by which nosocomial bacteria, like A. baumanii, attain multidrug resistance to antibiotics is of considerable interest. The aim in this study was to investigate the spread status of antibiotic resistance genes, such as multiple β-lactamase genes and aminoglycoside-modifying enzyme genes, from A. baumanii strains isolated from patients with lower respiratory tract infections (LRTIs).
Two thousand six hundred and ninety-eight sputum or the bronchoalveolar lavage samples from inpatients with LRTIs were collected in 21 hospitals in the mainland of China from November 2007 to February 2009. All samples were routinely inoculated. The isolated bacterial strains and their susceptibility were analyzed via VITEK-2 expert system. Several kinds of antibiotic resistant genes were further differentiated via polymerase chain reaction and sequencing methods.
Totally, 39 A. baumanii strains were isolated from 2698 sputum or bronchoalveolar lavage samples. There was not only a high resistant rate of the isolated A. baumanii strains to ampicillin and first- and second-generation cephalosporins (94.87%, 100% and 97.44%, respectively), but also to the third-generation cephalosporins (ceftriaxone at 92.31%, ceftazidine at 51.28%) and imipenem (43.59%) as well. The lowest antibiotic resistance rate of 20.51% was found to amikacin. The OXA-23 gene was identified in 17 strains of A. baumanii, and the AmpC gene in 23 strains. The TEM-1 gene was carried in 15 strains. PER-1 and SHV-2 genes were detected in two different strains. Aminoglycoside-modifying enzyme gene aac-3-Ia was found in 23 strains, and the aac-6'-Ib gene in 19 strains. aac-3-Ia and aac-6'-Ib genes hibernated in three A. baumanii strains that showed no drug-resistant phenotype.
A. baumanii can carry multiple drug-resistant genes at the same time and result in multi-drug resistance. Aminoglycoside-modifying enzyme genes could be hibernating in aminoglycoside sensitive strains without expressing their phenotype.
Preview · Article · Sep 2010 · Chinese medical journal
[Show abstract][Hide abstract] ABSTRACT: To investigate the relationship between clinical features of patients with A/H5N1 infection and their prognosis in mainland China.
This study included 28 human cases with A/H5N1 infection in mainland China from October 2005 to May 2008. Data were collected and reviewed from hospital medical records and publishied papers. A database was built by EPIDATA 3.02 and statistical analyses were performed with SPSS 13.0.
The median age of the 28 cases was 29 years (range 6-62), and 15 were females. Ten patients survived, and 18 died. The typically clinical manifestations of human influenza A/H5N1 infection included fever and lower respiratory infection. The numbers of peripheral white blood cells, lymphocytes and platelets in the survival and non-survival groups were (4.01 +/- 1.86) x 10(9)/L vs (5.1 +/- 2.9) x 10(9)/L, (1.09 +/- 0.49) x 10(9)/L vs (0.98 +/- 0.44) x 10(9)/L, and (116 +/- 39) x 10(9)/L vs (101 +/- 40) x 10(9)/L, respectively; the differences were not statistically significant between the 2 groups (P>0.05). There was also no statistically significant difference in the increased serum enzymes, such as aspartate aminotransferase [(173 +/- 246) U/L vs (272 +/- 263) U/L], lactate dehydrogenase [(1016 +/- 568) U/L vs (1512 +/- 1052) U/L], creatine kinase [(1099 +/- 1590) U/L vs (2534 +/- 4281) U/L] and MB isoenzyme of creatine kinase [(28 +/- 30) U/L vs (125 +/- 197) U/L] (P>0.05) between the survival and the non-survival groups. However, there was a statistically significant difference in the number of patients with an initial LDH level more than 8 fold of the normal value between the survival and the non-survival groups (none vs 6, P<0.05). All of the 28 cases developed bilateral multiple infiltrates and consolidation in chest radiographs. Acute respiratory distress syndrome occurred in 22 cases, 17 of them died. All the 9 patients with acute kidney injury died. Ten patients received antiviral treatment with oseltamivir, and 6 of them survived. There was a statistical difference in the time of initiating oseltamivir treatment between the survival and the non-survival cases [(6.5 +/- 3.0) d vs (11.8 +/- 3.3) d, Z = 3.70, P<0.05]. Broad spectrum antibiotics and corticosteroids were administered in all of the 28 cases. There was no statistical difference between the survival and the non-survival groups regarding to the corticosteroid treatment (P>0.05).
Initial LDH level reaching more than 8 fold of the normal value suggests a poor prognosis for human H5N1 infection. Patients complicated with either ARDS or acute kidney injury had a higher risk of death. Early administration of effective antiviral agents might improve the prognosis and decrease case fatality.
No preview · Article · May 2009 · Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases