A preliminary study on the potential of Mycoplasma pneumoniae to induce dyskaryotic change in respiratory epithelium in adult community-acquired pneumonia.

BACKGROUND: This study aimed to explore the cellular morphology of respiratory epithelium in Mycoplasma pneumonia (MpP) patients. MATERIALS AND METHODS: The cast-off cell morphological findings from bronchoscopic brushings in MpP and community-acquired pneumonia (CAP) caused by typical pathogens were reviewed. RESULTS: Compared with the CAP group, cellular dysplasia in respiratory tract epithelial brushings was significantly greater in MpP patients (P = 0.033). CONCLUSION: Unique biological characteristics and mechanisms of pathogenesis of Mycoplasma pneumoniae (Mp) may result in dyskaryotic changes in respiratory epithelium in adult MpP.

Preliminary molecular epidemiology of the Staphylococcus aureus in lower respiratory tract infections: a multicenter study in China.

BACKGROUND: 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. METHODS: 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). RESULTS: 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%. CONCLUSION: 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.

Dynamic changes of ocular biometric parameters: a modified form-deprivation myopia model of young guinea pigs.

AIM: To evaluate the dynamic ocular biometric changes of a modified form-deprivation myopia model in young guinea pigs. METHODS: THE ANIMALS WERE RANDOMLY ASSIGNED TO TWO GROUPS: the monocularly deprived facemask group (MDF, with all the right eyes covered, n=24) and the normal control group (free of facemask, n=24). Each group was then equally divided into four subgroups which were followed up for 2, 4, 6 and 8 weeks, respectively. Parameters measured from every eye included refraction, corneal curvature, axial length and the dry weight of sclera at the posterior pole. RESULTS: All the facemasks remained in place during the follow-up. The covered eyes developed myopia with the vitreous chamber lengthening and the dry weight of posterior sclera reduced at each time point compared with the contralateral uncovered (P<0.05 at all time points). The changes had a linear correlation with the deprivation time (P<0.05). There were no significant differences in all the parameters between the uncovered eyes of MDF group and the normal control group (P>0.05 at all time points). CONCLUSION: Monocular form deprivation with the facemask is highly effective and non-invasive in inducing axial myopia in guinea pigs. The axial myopia is mainly caused by the increased vitreous chamber length and the weakened posterior sclera rigidity. The form-deprivation eye didn't interfere with the natural development of the contralateral eye.

Drug-resistant genes carried by Acinetobacter baumanii isolated from patients with lower respiratory tract infection.

BACKGROUND: 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 ß-lactamase genes and aminoglycoside-modifying enzyme genes, from A. baumanii strains isolated from patients with lower respiratory tract infections (LRTIs). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

[Atypical pathogens in adult patients admitted with community-acquired pneumonia].

OBJECTIVE: To investigate the current status of atypical pathogen associated infections in community-acquired pneumonia (CAP) in adults, and their clinical attributes. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Evidence of human papilloma virus infection and its epidemiology in esophageal squamous cell carcinoma.

AIM: To look for the evidence of human papilloma virus (HPV) infection in esophageal squamous cell carcinomas (ESCC) and to investigate the potential role and epidemiology of HPV infection in the pathogenesis of esophageal carcinomas in Henan emigrants. METHODS: Papilloma virus(PV) and HPV were determined by Ultrasensive S-P immunohistochemistry (IHC) and in situ hybridization (ISH)in esophageal carcinoma tissues (82 cases) and the normal mucosa (40 cases). RESULTS: IHC revealed that the positive rate of PV was 75.0%, 68.18% and 72.5% respectively while the HPV (16/18-E6) positive rate was 45.0%,36.36%, 37.5%, respectively in esophageal carcinoma tissue specimens from Henan emigrants,the local citizens and patients in Hubei Cancer Hospital. The PV and HPV (16/18-E6) were negative in all normal esophageal mucosa specimens. No correlation was found between HPV in esophageal squamous cell carcinoma tissues and in grade 1-3 esophageal squamous cell carcinoma cells. In situ hybridization showed that the HPV (16/18) DNA positive rate was 30.0%, 31.8%, 25.0%, respectively in the 3 groups of samples. No positive hybridization signal was found in 40 normal esophageal mucosa specimens. The positive rate of HPV (16/18) DNA in the esophageal carcinoma specimens was significantly higher than that in normal mucosa specimens (P<0.05). The positive rate was not different among the 3 groups of esophageal carcinoma tissue specimens (P>0.05). CONCLUSION: HPV infection is high in esophageal carcinoma of Henan emigrants, local residents and patients in Hubei Cancer Hospital.HPV is closely related with esophageal squamous cell carcinoma. HPV infection may play an important role in esophageal squamous cell carcinoma.