Diagnosis of primary antibody and complement deficiencies in young adults after a first invasive bacterial infection.

OBJECTIVES: Screening for primary immunodeficiencies (PIDs) in adults is recommended after two severe bacterial infections. We aimed to evaluate if screening should be performed after the first invasive infection in young adults. METHODS: Eligible patients were retrospectively identified using hospital discharge and bacteriology databases in three centres during a 3-year period. Eighteen to 40-year-old patients were included if they had experienced an invasive infection with encapsulated bacteria commonly encountered in PIDs (Streptococcus pneumoniae (SP), Neisseria meningitidis (NM), Neisseria gonorrhoeae (NG), Haemophilus influenzae (HI), or group A Streptococcus (GAS)). They were excluded in case of general or local predisposing factors. Immunological explorations and PIDs diagnoses were retrieved from medical records. Serum complement and IgG/A/M testings were systematically proposed at the time of study to patients with previously incomplete PID screening. RESULTS: The study population comprised 38 patients. Thirty-six had experienced a first invasive episode and a PID was diagnosed in seven (19%): two cases of common variable immunodeficiency revealed by SP bacteraemia, one case of idiopathic primary hypogammaglobulinaemia, and two cases of complement (C6 and C7) deficiency revealed by NM meningitis, one case of IgG2/IgG4 subclasses deficiency revealed by GAS bacteraemia, and one case of specific polysaccharide antibody deficiency revealed by HI meningitis. Two patients had previously experienced an invasive infection before the study period: in both cases, a complement deficiency was diagnosed after a second NM meningitis and a second NG bacteraemia, respectively. CONCLUSION: PID screening should be considered after a first unexplained invasive encapsulated-bacterial infection in young adults.

Cefoxitin: An alternative to carbapenems in urinary tract infections due to extended-spectrum beta-lactamase-producing Enterobacteriaceae.

BACKGROUND AND OBJECTIVES: Infections caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) have become a major public health issue worldwide. Cefoxitin is a second-generation cephalosporin and is associated with a strong in vitro activity against ESBL. PATIENTS AND METHODS: We conducted a prospective monocentric cohort study from 2012 to 2015 to evaluate the clinical efficacy and safety of cefoxitin in 15 patients treated for urinary tract infection (UTI) caused by ESBL-E, without any severity criteria. RESULTS: We included 15 patients; 11 were male patients with defined risk factors for ESBL-E. Ten patients presented with male UTI, three with pyelonephritis, and two with cystitis. Escherichia coli was the predominant pathogen. All patients had a positive outcome with a good tolerance (a skin rash without any sign of severity was observed in one patient). Microbiological cure was obtained in 9 patients out of 10 at the end of treatment. CONCLUSION: Cefoxitin is an alternative treatment to carbapenems for urinary tract infections caused by ESBL-producing Enterobacteriaceae.

P. aeruginosa LPS stimulates calcium signaling and chloride secretion via CFTR in human bronchial epithelial cells.

BACKGROUND: Pseudomonas aeruginosa airway infection is associated with a high mortality rate in cystic fibrosis. Lipopolysaccharide (LPS), a main constituent of the outer membrane of P. aeruginosa, is responsible for activation of innate immune response but its role on airway epithelium ion transport, is not well known. The aim of this study was to determine the role for P. aeruginosa LPS in modulating chloride secretion and intracellular calcium in the human bronchial epithelial cell line, 16HBE14o-. METHODS: We used intracellular calcium imaging and short-circuit current measurement upon exposure of cells to P. aeruginosa LPS. RESULTS: Apical LPS stimulated intracellular calcium release and calcium entry and enhanced chloride secretion. This latter effect was significantly inhibited by CFTR(inh)-172 and BAPTA-AM (intracellular Ca(2+) chelator). CONCLUSIONS: Our data provides evidence for a new role of P. aeruginosa LPS in stimulating calcium entry and release and a subsequent chloride secretion via CFTR in human bronchial epithelium.

Factors associated with recurrence of catheter-related bloodstream infections in home parenteral nutrition patients.

Blood cultures from outpatients receiving home parenteral nutrition (HPN) via long-term central venous access (CVA) were retrospectively analyzed from January 2003 to May 2009. When infection of the CVA was not due to Staphylococcus aureus, Pseudomonas aeruginosa, or Candida, catheter salvage was attempted for a maximum of three consecutive infections on the same CVA. Factors influencing the time-to-next-infection were studied, whether the catheter was changed after the last infection or not. Neither the McCabe score, age, history of cancer, diabetes mellitus nor immunosuppression, curative antibiotic lock, type of bacteria, type or duration of treatment had an influence on the time-to-next-infection. The time-to-next-infection was significantly associated with the status of CVA (saved or changed) and its type (tunneled catheter with or without a cuff, or implanted port catheter).

[Kinetics of Pseudomonas aeruginosa virulence gene expression during chronic lung infection in the murine model]. / Cinétique d'expression des gènes de virulence de Pseudomonas aeruginosa au cours d'une infection pulmonaire chronique dans le modèle murin.

UNLABELLED: Pseudomonas aeruginosa is a Gram-negative bacillus frequently encountered in human diseases. P. aeruginosa produces a large number of secreted and cell associated virulence factors. Their production is coordinated by various systems of gene regulation. The correlation and sequential intervention of regulation systems during a pulmonary infection have not been determined yet. OBJECTIVE: The aim of this study was to analyze the expression of three P. aeruginosa virulence genes (exoS, lasI, and algD) during the first seven days of chronic lung infection. To do so, mice were infected intratracheally with agarose beads containing P. aeruginosa. RESULTS: The results were a progressive decrease of exoS transcription and an increase of algD, and lasI transcription during infection. This dynamic evolution was consistent with the clinical observation, which demonstrated a progressive loss of type III secretion system function and an increase in the mucoid phenotype development in P. aeruginosa strains from cystic fibrosis patients. CONCLUSION: The development of a P. aeruginosa pulmonary chronic infection associates a decrease of gene expression related to a type III secretion system and an increase of alginate production.

MN/CA9: a potential gene marker for detection of malignant cells in effusions.

Many cancers cause malignant effusions. The presence of malignant cells in effusions has implications in diagnosis, tumour staging and prognosis. The detection of malignant cells currently presents a challenge for cytopathologists. New adjunctive methods are needed. Although the effusions provide excellent materials for molecular assay, the available molecular markers are extremely limited, which hinders its clinical application. MN/CA9 has proved to be a valuable marker in many cancers such as lung, breast, colon, kidney, etc. The present study was to evaluate MN/CA9 as a new molecular marker for the detection of cancer cells in pleural effusions. Seventy-one pleural effusions including 59 malignant effusions from patients with cancer, and 12 patients with benign diseases as a control, were subjected to RT-PCR for detection of MN/CA9 gene expression. MN/CA9 gene expression was detected in 53/59 (89.8%) pleural effusions from cancer patients (15/16 for breast cancers, 10/11 for lung cancers, 4/4 for ovary cancers, 2/3 for colon-rectal cancers, 5/6 for cancers of unknown site, 7/8 for mesothelioma and 10/11 for other cancers). Furthermore, MN/CA9 was positive in 13/18 (72.2%) of cytologically negative effusions of cancer patients. MN/CA9 was detected in only 1/12 (8.3%) effusions from the control patients (p < 0.01). The sensitivity and specificity of MN/CA9 gene expression were, respectively, 89.8% and 91.7%. Our preliminary results suggest that MN/CA9 could be a potential marker for the detection of malignant cells in effusions. A large-scale study is needed to confirm these results.

Severe emphysematous pyelonephritis on a horseshoe kidney.

Emphysematous pyelonephritis is an acute bacterial infection responsible for a high mortality. It is characterized by bacterial gas production in the renal parenchyma, occurring in diabetic patients in most case. The gold standard treatment has always been surgery associated with antibiotic therapy. We report the case of a 58 year-old woman, with undocumented diabetes, who presented with emphysematous pyelonephritis complicated with septic shock and acute renal failure. Antibiotherapy alone was successful.

[Pseudomonas aeruginosa and Surfactant-associated Proteins A and D]. / Pseudomonas aeruginosa et surfactant rôle de SP-A et SP-D.

Surfactant-associated proteins A and D (SP-A and SP-D) are two pulmonary collectins that bind to bacterial, fungal and viral pathogens and have multiples classes of receptors on pneumocyte and macrophage membrane. They are chemoattractant for phagocytes, enhance uptake and killing of bacteria by macrophages and neutrophils. These molecules also act as activation ligand on macrophages and neutrophils to enhance phagocytosis, resulting in an increased bacterial clearance. Depending on activation of cells by stimuli, SP-A and SP-D modulate production of antimicrobial free radicals by phagocytes and secretion of cytokines. In vivo, SP-A deficient mice infected with Pseudomonas aeruginosa (P. aeruginosa) have decreased bacterial clearance and exacerbated inflammatory response in the lungs. Serious alterations in macrophages and increased production of reactive oxygen species were found in non-infected SP-D deficient mice. Patients with cystic fibrosis are frequently colonized by P. aeruginosa. Decreased levels of SP-A and SP-D have been measured in bronchoalveolar lavage fluid of these patients, as well as patients with acute pneumonia but no chronic lung disease. P. aeruginosa secretes various proteases, among them, elastase and protease IV have been found to degrade SP-A and SP-D and abrogate their immune function. However, further investigations are necessary to examine whether these deficiencies facilitate P. aeruginosa infections or stand as consequences.

Alveolar response to Pseudomonas aeruginosa: role of the type III secretion system.

The type III secretion system (TTSS) is a specialized cytotoxin-translocating apparatus of gram-negative bacteria which is involved in lung injury, septic shock, and a poor patient outcome. Recent studies have attributed these effects mainly to the ExoU effector protein. However, few studies have focused on the ExoU-independent pathogenicity of the TTSS. For the present study, we compared the pathogenicities of two strains of Pseudomonas aeruginosa in a murine model of acute lung injury. We compared the CHA strain, which has a functional TTSS producing ExoS and ExoT but not ExoU, to an isogenic mutant with an inactivated exsA gene, CHA-D1, which does not express the TTSS at all. Rats challenged with CHA had significantly increased lung injury, as assessed by the wet/dry weight ratio for the lungs and the protein level in bronchoalveolar lavage fluid (BALF) at 12 h, compared to those challenged with CHA-D1. Consistent with these findings, the CHA strain was associated with increased in vitro cytotoxicity on A549 cells, as assessed by the release of lactate dehydrogenase. CHA was also associated at 12 h with a major decrease in polymorphonuclear neutrophils in BALF, with a proinflammatory response, as assessed by the amounts of tumor necrosis factor alpha and interleukin-1beta, and with decreased bacterial clearance from the lungs, ultimately leading to an increased mortality rate. These results demonstrate that the TTSS has a major role in P. aeruginosa pathogenicity independent of the role of ExoU. This report underscores the crucial roles of ExoS and ExoT or other TTSS-related virulence factors in addition to ExoU.

[Viral pneumonia in immunocompetent patients]. / Pneumonie virale sévère de l'immunocompétent.

Respiratory infections are frequently encountered in the community; these infections are usually associated with only minor consequences. Many different agents, such as influenza and parainfluenza virus, respiratory syncitial virus, rhinovirus, coronavirus, adenovirus and herpes virus can be found in immuno-competent patients. Among these pathogens, cytomegalovirus (CMV) has been found to be responsible for nosocomial pneumonia in ICU. The main problem for viral infections, is the diagnosis, isolation of the pathogen is often difficult and not always reliable and the symptoms not specific. However, influenza is characterised by fever, myalgia, headache and pharyngitis, this infection may be very mild, even asymptomatic, moderate or very severe. Finally, the most recent viral pathogen involved in respiratory disease is a newly discovered coronavirus, the SARS-CoV which was responsible for the worldwide outbreak of Severe Acute Respiratory Syndrome. Viral pneumonia is a common pathology which is probably underdiagnosed in immuno-competent patients; many reports show that even if the diagnosis is difficult to obtain, it is not useless as long as we have, for most of the pathogens, an effective treatment. The gold standard was histology, new techniques like PCR can probably make a difference and should be included in the guidelines to improve diagnostic efficiency.

The expression of G250/mn/CA9 antigen by flow cytometry: its possible implication for detection of micrometastatic renal cancer cells.

Monoclonal antibody (mAb) G250 is a well characterized and specific mAb to renal cell carcinoma (RCC). The gene G250 was recently cloned and was proved to be homologous to MN/CA9. The G250/MN/CA9 antigen was recently explored as a potential marker for RCC. Flow cytometry (FCM) allows quantitative analysis of cells. The present study describes a flow cytometric method to detect this antigen in human cell lines and in malignant and normal renal tissues. Twelve human carcinoma cell lines (HeLa, Colo205, HT29, BxPC3, OVCAR3, SKOV3, ACHN, A704, CAKI-2, SKRC-59, SKRC-10, and SKRC-52), 10 specimens of normal peripheral blood mononuclear cells, and 38 malignant and 36 adjacent normal renal tissues were studied. The malignant and normal renal tissues were disaggregated mechanically into a single-cell suspension, stained by mAb G250, and analyzed by FCM. All 22 of the clear cell carcinomas, 6 of 8 mixed cell carcinomas, and 3 of 6 granular cell carcinomas were positive for G250/MN/CA9 antigen. SKRC-52 and SKRC-10 were strongly positive for G250/ MN/CA9. The G250/MN/CA9 antigen could also be detected in HeLa, SKOV3, HT29, and A704 cells. One chromophobic, one chromophilic cell carcinoma, the normal renal tissues, and normal peripheral blood mononuclear cells were considered as negative. Our results further confirmed that the G250/MN/CA9 antigen was an ideal marker for RCC, especially for clear cell carcinomas, and that this antigen was present in several types of malignant cells. FCM may serve as a fast tool of immunocytochemical detection of renal cancer cells. Flow cytometric detection of renal cancer cells by using mAb G250 should be further explored.

Flow cytometric analysis of antigen expression in malignant and normal renal cells.

UNLABELLED: Flow cytometry allows quantitative analysis of cancer cells. The aim of this study was to make a quantitative study of antigen expression in malignant and normal renal cells in order to find the efficient monoclonal antibodies (mAbs) for labelling renal cancer cells. MATERIAL AND METHODS: 15 malignant and adjacent normal renal tissues and three renal carcinoma cell lines (ACHN, A704 and CAKI-2) were analyzed. The malignant and normal renal tissues were dissociated mechanically into cell suspension. The mAbs and isotype controls were used for immunochemical labelling. The stained cells were analyzed by flow cytometry. RESULTS: Renal tumor associated antigen G 250 was frequently detected in malignant renal cells but not in normal renal cells. Renal tumor associated antigen gp200 recognized by 66.4.C2 and PN-15 was frequently detected in malignant cells, normal renal cells and also in all three carcinoma cell lines. Epithelial antigens were strongly positive in normal renal cells. Compared with MOC 31, Ber-EP4 and E 29, W-lD9 was mostly reactive to malignant renal cells. VU-1D9 was strongly positive on ACHN and A704. The carbohydrate carcinoma antigens CA 125, DF3 and Sialyl Lewis(a) were detectable in some of the malignant and normal renal cells. Sialyl Lewis(a) could be weakly detected on ACHN and A 704. Pan-cytokeratins and cytokeratin (CK) 8 were strongly expressed in malignant and normal renal cells and in all three cell lines. CONCLUSION: Our results indicated that G 250, 66.4.Ca, PN-15, VU-1D9, MNF116 and anti-ckg were efficient mAbs for labelling renal cancer cells. Their potential clinical application by flow cytometry should be explored.