[Type I interferon and bacterial infection].

Interferons (IFNs) are cytokines playing an important role in immune responses. Interferons are classified into two distinct types according to specific interferon receptors(IFNR). Type I IFNs include IFN-α and IFN-ß, whereas IFN-γ is type II IFN. It is well known that type I IFNs have important roles in the host defense against viruses through activation of interferon receptor A (IFNAR). However, many recent studies have also demonstrated that type I IFNs have effects on immune responses to bacterial infection. This review focuses on the immune regulation of type I IFN-mediated signal pathways in bacterial infections such as Listeria monocytogenes, Streptococcus, Mycobacterium tuberculosis, Bacillus anthracis, Legionella, Pseudomonas aeruginosa and others.

Efficacy and significance of various scores for pneumonia severity in the management of patients with community-acquired pneumonia in China.

BACKGROUND: Community-acquired pneumonia (CAP) remains one of the leading causes of death from infectious diseases around the world. Most severe CAP patients are admitted to the intensive care unit (ICU), and receive intense treatment. The present study aimed to evaluate the role of the pneumonia severity index (PSI), CURB-65, and sepsis score in the management of hospitalized CAP patients and explore the effect of ICU treatment on prognosis of severe cases. METHODS: A total of 675 CAP patients hospitalized in the Second Affiliated Hospital of Zhejiang University School of Medicine were retrospectively investigated. The ability of different pneumonia severity scores to predict mortality was compared for effectiveness, while the risk factors associated with 30-day mortality rates and hospital length of stay (LOS) were evaluated. The effect of ICU treatment on the outcomes of severe CAP patients was also investigated. RESULTS: All three scoring systems revealed that the mortality associated with the low-risk or intermediate-risk group was significantly lower than with the high-risk group. As the risk level increased, the frequency of ICU admission rose in tandem and LOS in the hospital was prolonged. The areas under the receiver operating characteristic curve in the prediction of mortality were 0.94, 0.91 and 0.89 for the PSI, CURB-65 and sepsis score, respectively. Compared with the corresponding control groups, the mortality was markedly increased in patients with a history of smoking, prior admission to ICU, respiratory failure, or co-morbidity of heart disease. The differences were also identified in LOS between control groups and patients with ICU treatment, heart, or cerebrovascular disease. Logistic regression analysis showed that age over 65 years, a history of smoking, and respiratory failure were closely related to mortality in the overall CAP cohort, whereas age, ICU admission, respiratory failure, and LOS at home between disease attack and hospital admission were identified as independent risk factors for mortality in the high-risk CAP sub-group. The 30-day mortality of patients who underwent ICU treatment on admission was also higher than for non-ICU treatment, but much lower than for those patients who took ICU treatment subsequent to the failure of non-ICU treatment. CONCLUSIONS: Each severity score system, CURB-65, sepsis severity score and especially PSI, was capable of effectively predicting CAP mortality. Delayed ICU admission was related to higher mortality rates in severe CAP patients.

Outbreak of Klebsiella pneumoniae carbapenemase 2-producing K. pneumoniae with high qnr prevalence in a Chinese hospital.

Forty carbapenem-resistant Klebsiella pneumoniae isolates were recovered from 28 patients from various sites in an intensive care unit in Zhejiang Provincial People's Hospital, China, over a 6 month period. PFGE analysis indicated that the 40 strains were all closely related. The MICs of carbapenems varied from 16 to >256 µg ml⁻¹. Conjugation studies with Escherichia coli resulted in the transfer of reduced carbapenem susceptibility from the original isolates. All K. pneumoniae and E. coli transconjugants produced K. pneumoniae carbapenemase 2 (KPC-2), and most of them produced TEM, SHV and CTX-M. Additionally, 27 isolates and 27 E. coli transconjugants carried the qnr gene (25 were qnrB2 and 2 were qnrS1). K. pneumoniae harboured several plasmids, and bla(KPC-2) was located on a 55 kb plasmid. SDS-PAGE and ompK35/36 gene sequence analysis of OMPs suggested that porins in K. pneumoniae are expressed normally. The MICs of the carbapenems did not change in the presence of CCCP. Thus, production of KPC-2 appears to play an important role in resistance to carbapenems, although other mechanisms may be involved. The bla(KPC-2) gene is associated with several antibiotic-resistance genes, such as bla(TEM), bla(SHV), bla(CTX-M) and qnr.

Hyperoxygenated solution for improved oxygen supply in patients undergoing lung lavage for pulmonary alveolar proteinosis.

BACKGROUND: At present, the most effective treatment for pulmonary alveolar proteinosis (PAP) remains whole-lung lavage in spite of the usually accompanying severe hypoxemia, which is expected to be prevented by hyperoxygenated solution improving oxygen supply during lavage. In this study, the efficacy and safety of the effect of hyperoxygenated solution were evaluated. METHODS: Five patients underwent whole-lung lavage over a 28-month period. Each lung was lavaged with hyperoxygenated (HO) and normal saline solution (plain lactated Ringer's solution, NO) randomly and alternatively until the reclaimed fluid was clear. Random number was generated by computer before every cycle of lavage. If the number was odd, the patient was assigned to receive a lavage cycle with hyperoxygenated solution (HO group, n = 109); if the number was even, normal saline solution was used (NO group, n = 115). Data of saturation of peripheral oxygen (SPO(2)), mean arterial pressure (MAP), central venous pressure (CVP), heart rate (HR) and end-tidal carbon dioxide tension (P(ET)CO(2)) were taken down at 0, 30, 60, 90, 120, 150, 180, 210 and 240 seconds from the beginning of the instillation of solution, and frequency and volume of unilateral lung lavage were also recorded. Time interval between the left and the right lung lavage was 1 week. RESULTS: No patient was withdrawn from the study due to low SPO(2) or leakage. Oxygen pressure was (730.21 +/- 7.43) mmHg in the hyperoxygenated solution against (175.73 +/- 5.92) mmHg in the normal saline solution (P < 0.01). Compared with baseline, SPO(2) increased significantly as the instillation of solution began (P < 0.01), leveled for about 30 seconds (P > 0.05), and then decreased significantly to the lowest at the time of drainage (compared with 120 seconds or peak, P < 0.01). SPO2 was higher in HO group than in NO group (P < 0.01). There were no significant differences in MAP, HR, CVP and P(ET)CO(2) between HO group and NO group (P > 0.05) and also among different time points (P > 0.05). CONCLUSION: During the lung lavage for pulmonary alveolar proteinosis, hyperoxygenated solution could significantly improve oxygen supply in comparison with normal saline solution without obvious side effects.

Reduced susceptibility to carbapenems in Klebsiella pneumoniae clinical isolates associated with plasmid-mediated beta-lactamase production and OmpK36 porin deficiency.

Two carbapenem-non-susceptible Klebsiella pneumoniae isolates, Z2554 and Z2110, were collected from a hospital in China and analysed by PFGE. K. pneumoniae Z2554 and Z2110 were genetically unrelated and showed resistance to ertapenem, and reduced susceptibility to imipenem and meropenem. Analysis of their beta-lactamases indicated that K. pneumoniae Z2554 produced TEM-1 and CTX-M-14 beta-lactamases, whilst Z2110 produced a plasmid-mediated AmpC beta-lactamase, DHA-1, in addition to TEM-1 and CTX-M-14. SDS-PAGE analysis of the outer-membrane proteins (OMPs) revealed that both isolates lacked an OMP of approximately 39 kDa (OmpK36), whilst Z2110 had an additional protein with an approximate molecular mass of 26 kDa. Analysis of the OMP-encoding genes demonstrated that the ompK35 sequence of K. pneumoniae Z2554 and Z2110 contained a number of silent mutations. In ompK36, several insertions and deletions of short DNA fragments (1-6 bp) were detected in both isolates. The N-terminal sequence of the approximately 26 kDa protein band identified in Z2110 had no similarity to the sequence of OmpK36. Instead, it shared high similarity with hypothetical protein KPN_03267 originating from K. pneumoniae subsp. pneumoniae MGH 78578. It was concluded that beta-lactamase production combined with OmpK36 deficiency results in ertapenem resistance, and reduced imipenem and meropenem susceptibility, in K. pneumoniae Z2554 and Z2110. OmpK36 may play an important role in the resistance or reduced susceptibility to carbapenems in K. pneumoniae producing AmpC, extended-spectrum beta-lactamase or broad-spectrum beta-lactamase.

The diagnostic significance of the detection of cytokeratin 19 mRNA by quantitative RT-PCR in benign and malignant pleural effusions.

OBJECTIVE: To evaluate the diagnostic significance of detecting cytokeratin 19 (CK19) mRNA by quantitative reverse transcription polymerase chain reaction (RT-PCR) in benign and malignant pleural effusions. METHODS: CK19 mRNA was examined by quantitative RT-PCR and CK19 was detected by Enzyme-linked immunoadsorbent assay (ELISA) in 32 patients with malignant pleural effusions and 35 patients with benign pleural effusions. RESULTS: On the threshold of 200 copies/microl, the positive rate of CK19 mRNA in patients with malignant pleural effusions was 62.5%. The positive rates of CK19 mRNA and CK19 in the malignant pleural effusions were significantly higher than those in the benign group (P<0.01). Furthermore, the positive rate of CK19 mRNA was higher than that of CK19 in the malignant group (P<0.05). CONCLUSION: Detection of CK19 mRNA can be a promising diagnostic marker in differential diagnosis of benign and malignant pleural effusions.