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.

[The effect of subglottic secretion drainage on prevention of ventilator-associated lower airway infection].

OBJECTIVE: To assess the influence of subglottic secretion drainage (SSD) on the morbidity of ventilator-associated pneumonia (VAP) in mechanically ventilated patients. METHODS: All studied patients who received mechanical ventilation (MV) estimated for more than 48 hours were intubated with a special type endotracheal tube with a small-bore cannula in the wall for SSD. The patients were randomly divided into two groups receiving SSD (group A) and usual care (non-SSD, group B) respectively. Bacterial culture of samples from lower airway secretion taken regularly by Bagpipe Protected specimen brush were performed, and at the same time the subglottic secretion and scraping-pharynx specimen were collected for bacterial quantitative culture and antibiotic sensitivity test. The clinical data were recorded and the duration of MV, the length of stay in hospital and the time of occurrence of ventilator-associated airway infection (VAAI) and VAP were analyzed. RESULTS: (1) In patients with MV < 5 days: The incidence of VAAI and VAP in group A (VAAI: 8.3% and VAP: 6.0%) was lower than those in group B (VAAI: 24.0% and VAP: 20.0%, P < 0.05). The onset of VAAI and VAP was delayed in group A [VAAI: (7.4 +/- 3.0) d and VAP: (7.7 +/- 3.2) d] as compared with group B [VAAI: (4.9 +/- 1.4) d and VAP: (4.6 +/- 2.1) d, P < 0.05]. There were no significantly statistic differences for hospital mortality, overall duration of mechanical ventilation, lengths of stay in the hospital between the two groups (P > 0.05). (2) The same organism as that previously found from subglottic secretion was isolated by PSB in 21.4% patients. (3) The concentration of bacteria in subglottic secretion from group A was decreased significantly as compared to that of group B. (4) Gram-negative bacilli were the main pathogens in the lower respiratory tract in the two groups. The dominant bacteria cultured in the lower airway secretions were Pseudomonas aeruginosa and Acinetobacter baumanii. There was no significant difference between the two groups in the spectrum of bacteria (P > 0.05). CONCLUSIONS: (1) SSD reduced the incidence of VAAI and VAP in patients with MV < 5 d. The onset of VAAI and VAP was delayed in group A as compared with group B. The concentration of bacteria in the subglottic secretion was significantly reduced by subglottic secretion drainage. (2) Migration of the dominant bacteria of the subglottic secretion was one of the important factors for VALAI. (3) The dominant cultured bacteria in the lower airway secretion were gram-negative bacilli, most commonly Pseudomonas aeruginosa and Acinetobacter baumanii.

Prevalence and characterization of plasmid-mediated blaESBL with their genetic environment in Escherichia coli and Klebsiella pneumoniae in patients with pneumonia.

BACKGROUND: The extended spectrum ß-lactamase (ESBL)-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the major pathogens causing pneumonia and have a significant impact on the clinical course. Limited data exist on molecular characterization of ESBL-producing E. coli and K. pneumoniae that cause pneumonia. The aim of this study was to investigate the comprehensive multilevel characteristics of E. coli and K. pneumoniae causing pneumonia in China for the first time. METHODS: E. coli (17) and K. pneumoniae (21) isolates responsible for pneumonia were isolated from 1270 specimens collected in a prospective multi-center study in eight teaching hospitals in China from June to December in 2007. The susceptibilities, ESBL confirmation, sequence typing, blaCTX-M and blaSHV genes, their genetic environment and plasmid Inc/rep types were determined. RESULTS: Sixteen E. coli (94.1%) and eleven K. pneumoniae (52.4%) isolates were ESBL producers. About 77.8% and 66.7% of them were resistance to ciprofloxacin and levofloxacin, and 100% were susceptible to imipenem. The most prevalent ESBL gene was CTX-M-14, followed by SHV-2, CTX-M-15, CTX-M-3, CTX-M-65, SHV-12, SHV-26 and SHV-28. SHV-1 and SHV-11 were also detected and coexisted with blaCTX-Ms in five strains, and three strains contained only SHV-1. All CTX-M-14 were detected ISEcp1 upstream and nine were found IS903 downstream and the majority of them (64.3%) were carried by IncF plasmids. All blaSHV were flanked by recF and deoR, located on IncF, IncN, IncX and IncH plasmids. Two SHV-2, one SHV-1 and the only SHV-28 were further preceded by IS26. Genes lacY and lacZ were detected at further upstream of two blaSHV-1. The K. pneumoniae carrying SHV-28 was susceptible to ß-lactams, and no mutations or deletions in gene or promoter sequences were identified to account for susceptibility. Multilocus sequence typing experiments showed the ESBL-producing strains were genetically diverse. CONCLUSIONS: The rate of occurrence of blaESBL in E. coli and K. pneumoniae causing pneumonia was high, and blaCTX-M-14 was dominant and probably mobilized by ISEcp1 mainly on IncF plasmids. Importantly, unexpressed blaESBL genes may occur in susceptible isolates and hence may have clinical implications.

Triple combinations of neuraminidase inhibitors, statins and fibrates benefit the survival of patients with lethal avian influenza pandemic.

The high mortality of highly pathogenic avian influenza A (H5N1) viruses infection in humans gives rise to considerable concern that it might someday cause another lethal pandemic. At present there is no other effective alternative besides the early and enough administration of neuraminidase inhibitors, which may be crucial for the patient management. However, its efficacy is sometimes limited because of the late administration in some patients especially the seriously ill ones and the continual occurrence of oseltamivir resistant A (H5N1) strains. The specific candidate vaccine are still under development and the practical value of passive immunization is hard to be widely applied because of the scarcity of convalescent human plasma, especially in the early stage of a serious and rapidly progressing pandemic. Statins and fibrates, both of which are used in clinical practice, have anti-inflammatory and immunomodulatory effects and other multiple biologic activities. So we hypothesized that the two immunomodulatory agents may exhibit synergistic effects when they were combined to neuraminidase inhibitors to treat the A (H5N1) viruses infections via inhibiting the production of either the early inflammatory mediators (e.g., many cytokine/chemokine) or the late mediator (e.g., High Mobility Group Box Protein 1), even showing the anti-viral activities with the prevention of the development of antiviral resistance. Therefore, the novel triple combinations may be an optimal management to confront the next lethal influenza pandemic on its very beginning.