Comparative analyses of albumin/globulin grain proteome fraction in differentially salt-tolerant Tunisian barley landraces reveals genotype-specific and defined abundant proteins.

Salinity is one of the major abiotic stresses threatening crop production and yield worldwide. Breeding programmes are therefore needed to improve yield under cultivation in soil. Traits from locally adopted landraces provide a resource to assist breeding of novel elite genotypes. Here, we examine differentially expressed proteins by performing comparative proteomic profiling of the albumin/globulin grain fraction of Tunisian barley genotype landraces with contrasting salinity tolerance. Tunisian barley Boulifa (B, tolerant) and Testour (T, sensitive) mature grains were assessed in 2-DE profiles. Differentially expressed spots, with an abundance enhanced 1.5-fold in the grain, were subjected to MALDI TOF/TOF MS for identification. Distinctiveness between tolerant and sensitive genotypes was proved in the albumin/globulin fraction using PCA; 64 spots showed significant differential abundance. Increased accumulation of 40 spots was confirmed in Boulifa with, interestingly, four genotype-specific spots. Two of these four spots were sHSP. Proteins with highest abundance were serpin Z7, 16.9 KDa Class I HSP and phosphogluconolactonase 2. Proteins such as expansin, kiwellin, kinesin and succinyl-CoA ligase were identified for the first time in barley grain. Moreover, ß-amylase, LEA family and others were identified as abundant in Boulifa. On the other hand, proteins more accumulated in Testour are implicated mainly in ROS scavenging and protease inhibition. Our results clearly indicate proteomic contrast between the two selected genotypes. With identification of specific HSP, high abundant stress-protective and other defined proteins, we provide biochemical traits that will support breeding programmes to address the threat of salinity in agricultural production.

High medical impact of implementing the new polymeric bead-based BacT/ALERT® FAPlus and FNPlus blood culture bottles in standard care.

Blood culture (BC) efficiency is critical for the diagnosis of bloodstream infection (BSI). We evaluated the impact on standard care of implementing the new BacT/ALERT® FAPlus and FNPlus BC bottles containing antibiotic-binding polymeric beads. We measured positivity rates and time to detection (TTD) during the first 10 months of implementation (PF) and during the previous 10-month period (PS) during which we were using standard aerobic (SA) or standard anaerobic (SN) BC bottles. For each period, the same number of consecutive patients (n = 3,918) was included. Per patient, a median of 1 BC set (1 aerobic and 1 anaerobic bottles) has been sampled. A higher positivity rate was measured during PF than PS when counting per BC bottle (7.0 % vs 5.8 % with 1,456 and 1,237 positive bottles respectively, P < 0.0001) and per BC set (9.6 % vs 7.8 % with 995 and 832 positive BC sets respectively, P < 0.0001). In PF, an increased number of cases due to staphylococci (P < 0.0001) and to Gram-negative bacilli (P < 0.005) was observed, whereas the contamination rate was similar during the two periods (2.4 % of BC sets in PF and 2.3 % in PS). Although antibiotic consumption and medical activity were similar during the two periods, BSI case detection increased from 2.2 to 2.6 per 1,000 hospital-days, especially in intensive care units (ICU; 35.1 to 55.7). Mean TTD for pathogenic microorganisms was significantly shorter in PF than in PS (15.5 h vs 18.0 h, P < 0.01). In conclusion, the use of the new FAPlus/FNPlus BC bottles improved the diagnosis of bacteremia in our hospital, especially in ICU patients.

Appearance of aac(6')-Ib-cr gene among extended-spectrum beta-lactamase-producing Enterobacteriaceae in a French hospital.

OBJECTIVES: The aac(6')-Ib gene encodes many variants of an aminoglycoside-acetyltransferase enzyme that is responsible for amikacin resistance. Recently, a new variant aac(6')-Ib-cr capable of modifying aminoglycosides and fluoroquinolones has been described. The aim of our study was to observe the appearance and the location of the aac(6')-Ib gene in extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae strains. METHODS: Sixty-six and nine non-clonal ESBL-producing Enterobacteriaceae strains were isolated, respectively, for one 3-year period from 1999 to 2001 and one 2-month period in 2005 in a French Hospital (Paris, France). RESULTS: Among these isolates, 35 of them carried the aac(6')-Ib gene. Fourteen out of the aac(6')-Ib genes of the period 1 and two of the period 2 were genes cassette located within class 1 integrons, whereas 16 and 3, respectively, were outside integrons. One of these encoded an aminoglycoside-acetyltransferase enzyme leading to an acetyltransferase that confers resistance to all aminoglycosides. The new -cr variant of aac(6')-Ib was detected in three Escherichia coli isolates in 2005 always associated with CTX-M-15 enzyme. CONCLUSIONS: The aac(6')-Ib-cr gene, responsible for antibiotic resistance to two very different drugs, is emerging in ESBL-producing Enterobacteriaceae strains isolated in France especially in strains carrying the bla(CTx-M-15) gene.

Improved diagnosis specificity in bone and joint infections using molecular techniques.

OBJECTIVES: The microbiological diagnosis of osteoarticular infections currently relies on microbiological cultures, to specifically target treatment. However, these conventional methods sometimes lack of sensitivity and of specificity to establish definitive diagnosis. This study was conducted to determine whether molecular method could improve bacterial bone and joint infection diagnosis. METHODS: We evaluated the performance of nucleic acid extraction with the semi-automated NucliSens miniMAG instrument coupled to 16S rDNA sequencing on 76 samples collected from 51 patients with suspected infections: prosthetic-joint infection (15), spondylodiscitis (7) acute septic arthritis (11) and 18 controls. No pre-treatment of the sample was done before nucleic acid extraction. Classification in infected group required an accumulation of arguments. RESULTS: Our molecular method identified a broad spectrum of pathogenic bacteria including Staphylococcus aureus, Streptococcus pyogenes, Streptococcus agalactiae, Enterococcus faecalis, Salmonella enterica, Escherichia coli, Pseudomonas aeruginosa, and fastidious bacteria like Neisseria gonorrhoeae and Fusobacterium nucleatum. The overall PCR sensitivity was 73.3%: 53.8% for prosthetic-joint infections and 88.2% for infections without prostheses. The overall PCR specificity was 95.2%, whereas culture specificity was only 85.7%. CONCLUSIONS: The instrument was simple to use and provided nucleic acids free of PCR inhibitors and free of contamination by foreign bacterial DNA. Our study highlights the need for still improved molecular diagnostic sensitivity.

Clostridium difficile brain empyema after prolonged intestinal carriage.

Clostridium difficile, the most common cause of antibiotic-associated diarrhea, is occasionally isolated from extraintestinal sites and is usually found as part of a polymicrobial flora. We report a case of brain empyema that occurred after the recurrent intestinal carriage of a nontoxigenic strain of C. difficile. Brain abscess cultures contained both toxigenic and nontoxigenic isolates. Pulsed-field gel electrophoresis showed that nontoxigenic isolates from the intestine and from the brain were identical.