The epidemiology of recurrent Gram-negative bacteremia in a tertiary-care hospital
We examined recurrent Gram-negative bacteremia in a prospective cohort from a tertiary hospital. Seventeen (7.1%) of 241 bacteremic patients developed recurrence (median time to recurrence = 44 days; range, 9–217 days). Recurrent and nonrecurrent bacteremic patients did not differ in clinical characteristics and mortality. (Source: Diagnostic Microbiology and Infectious Disease)...
POSTED 03/12/2010 at 10:32 AM --
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Vibrio parahaemolyticus-associated gastroenteritis in Italy: persistent occurrence of O3:K6 pandemic clone and emergence of O1:KUT serotype
We report 2 cases of O3:K6 and O1:KUT Vibrio parahaemolyticus gastroenteritis associated with consumption of local mussels in Italy in 2008. Serotypic, antibiogram, toxigenic, and pulsed-field gel electrophoresis patterns of these strains were compared to those of other isolates collected from local clinical and seafood samples in 2007 to 2008. We underline the recurrent presence of O3:K6 pandemic clone and the emergence of trh-positive O1:KUT serotype in Italy. (Source: Diagnostic Microbiology and Infectious Disease)...
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Demonstration and utility of clustered pseudohyphae on Gram-stained smears from Candida albicans-positive blood cultures
Abstract: The presence of clustered and branched pseudohyphae was investigated on Gram-stained smears of 78 consecutive yeast-positive blood cultures. The accuracy of the method was 96.1%, with a positive predictive value of 96.6% for Candida albicans. These findings demonstrate that the presence of clustered and branched pseudohyphae on Gram stain may be used for the rapid and presumptive identification of C. albicans from yeast-positive blood culture bottles. (Source: Diagnostic Microbiology and Infectious Disease)...
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Mechanisms of carbapenem resistance among a collection of Enterobacteriaceae clinical isolates in a Texas city
Abstract: Fourteen Enterobacteriaceae isolates with ertapenem MIC >2 mg/mL were analyzed to identify mechanisms of resistance. All isolates produced extended-spectrum β-lactamase or AmpC β-lactamase with variable, but decreased, expression of outer membrane proteins. One Enterobacter cloacae produced derepressed AmpC β-lactamase, 1 Escherichia coli expressed plasmid-mediated AmpC β-lactamase, and 1 E. cloacae produced a carbapenemase. (Source: Diagnostic Microbiology and Infectious Disease)...
POSTED 03/12/2010 at 10:32 AM --
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An enhanced method for the identification of Leishmania spp. using real-time polymerase chain reaction and sequence analysis of the 7SL RNA gene region
Abstract: The accurate identification of Leishmania spp. is important for the treatment of infected patients. Molecular methods offer an alternative to time-consuming traditional laboratory techniques for species determination. We redesigned a 7SL RNA gene-based polymerase chain reaction and sequence assay for increased species identification. DNA extracted from 17 reference strains and 10 cultured clinical isolates was examined. Sequence comparison was used successfully to identify organisms to the complex level with intercomplex similarity ranging from 77.5% to 98.4%. Many species within each complex were discriminated accurately by this method including Leishmania major, Leishmania tropica, Leishmania aethiopica, Leishmania guyanensis, and the previously indistinguishable Leishmania bra......
POSTED 03/12/2010 at 10:32 AM --
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Plasmid-mediated quinolone resistance determinants qnr and aac(6′)-Ib-cr in Escherichia coli and Klebsiella spp. from Norway and Sweden
Abstract: The prevalence of the plasmid-mediated quinolone resistance genes qnr and aac(6′)-Ib-cr was investigated among clinical isolates of Escherichia coli and Klebsiella spp. selected from 2 collections of consecutive isolates collected in 2004 to 2005 in Norway (n = 2479) and Sweden (n = 2980) and 1 group of extended-spectrum β-lactamase (ESBL)-producing isolates collected in 2003 in Norway (n = 71). A total of 414 isolates was selected for screening based on resistance to nalidixic acid and/or reduced susceptibility/resistance to ciprofloxacin. The prevalence of both qnr and aac(6′)-Ib-cr was higher among the ESBL producers (9.1% and 52.3%, respectively) than in the consecutive isolates (1.1% and 3.2%, respectively). qnrS1 was detected in 6 isolates, whereas qnrB1 and qnrB7 were......
POSTED 03/12/2010 at 10:32 AM --
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Molecular characterization of moxifloxacin resistance from Canadian Clostridium difficile clinical isolates
Abstract: Fluoroquinolone resistance in Clostridium difficile has been implicated in recent outbreaks of C. difficile infection. The purpose of this report was to characterize the molecular mechanism conferring resistance to moxifloxacin among C. difficile clinical isolates. Eighty-four C. difficile clinical isolates (collected as part of the Canadian Nosocomial Infection Surveillance Program) were evaluated in the current study. Pulsed-field gel electrophoresis was used to type the isolates. Susceptibility testing was performed using Clinical and Laboratory Standards Institute agar dilution methods. The quinolone resistance-determining region of both gyrA and gyrB was amplified using polymerase chain reaction and sequenced for each isolate. The proportion of isolates studied by the North ......
POSTED 03/12/2010 at 10:32 AM --
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In vitro activity of tigecycline against patient isolates collected during phase 3 clinical trials for diabetic foot infections
Abstract: The in vitro activity of tigecycline and comparative antimicrobial agents was evaluated against 1828 primary baseline pathogens isolated from 844 patients enrolled in the phase 3 clinical trials investigating the efficacy of tigecycline in diabetic foot infection (DFI). The trials were global, enrolling patients in 30 countries. Tigecycline was active against the most prevalent pathogens in DFI, including Gram-positive and Gram-negative isolates of both aerobic and anaerobic bacteria with 95% of MICs ≤2 μg/mL for the entire collection. The spectrum of activity of tigecycline included important pathogens for DFI, such as Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, and Bacteroides fragilis......
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Chlamydia pneumoniae IgG and IgA antibody titers and prognosis in patients with coronary heart disease: results from the CLARICOR trial
Abstract: The association observed between coronary heart disease (CHD) and Chlamydia (Chlamydophila) pneumoniae antibodies prompted, during the 1990s, several primary and secondary prevention trials with various antibiotics. In our CLARICOR trial, a randomized placebo-controlled trial in 4372 patients with stable CHD, a brief clarithromycin regimen was followed, unexpectedly, by increased long-term mortality. We now compare C. pneumoniae antibody levels at entry with population levels, with the patients' individual histories, and with their subsequent outcomes. IgG antibody levels were somewhat raised, but elevated IgA and IgG titers were unrelated to entry data (including prior acute myocardial infarction), except for an association with smoking and with not using statins. Hazards of mor......
POSTED 03/12/2010 at 10:32 AM --
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Screening for amino acid substitutions in the Candida albicans Erg11 protein of azole-susceptible and azole-resistant clinical isolates: new substitutions and a review of the literature
In this study, we investigated the antifungal susceptibility to fluconazole, itraconazole, and voriconazole of 73 clinical isolates of Candida albicans. Screening for amino acid substitutions in Erg11 was performed on each of the 73 isolates. Twenty isolates displayed a marked decrease in azole susceptibility. Amino acid substitutions were detected in more than two-thirds of the strains. In all, 23 distinct substitutions were identified. Four have not been described previously, among which N136Y and Y447H are suspected to be involved in azole resistance. We suggest that the high genetic polymorphism of ERG11 must be considered in the rationale design of new azole compounds targeting lanosterol 14α-demethylase. A review of all Erg11 amino acid polymorphisms described to date is given. (Sou......
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kDNA minicircle signatures of Leishmania (Viannia) braziliensis in oral and nasal mucosa from mucosal leishmaniasis patients
Abstract: Polymerase chain reaction (PCR) and low-stringency single-specific primer PCR (LSSP-PCR) analyses were used to detect Leishmania (Viannia) braziliensis DNA and investigate kDNA signatures of parasite populations present in oral and nasal mucosa lesions from mucosal leishmaniasis patients. A total of 25 samples from 22 patients were processed by specific PCR/hybridization assays. Parasite DNA was detected in all samples analyzed. The intraspecific polymorphism of the variable region of L. (V.) braziliensis kDNA minicircles was also investigated by LSSP-PCR. Similar kDNA signatures were observed in parasites recovered from nasal and oral mucosa lesions of the same patient. In contrast, genetically divergent profiles were detected in lesions from patients biopsied at different times......
POSTED 03/12/2010 at 10:32 AM --
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Acute HIV infection among pregnant women in Malawi
Abstract: There are limited data on acute HIV infection (AHI) prevalence during pregnancy. Malawian pregnant women admitted in the third trimester and meeting eligibility criteria underwent dual HIV rapid antibody testing. AHI prevalence was retrospectively detected through HIV RNA pooling of seronegative plasma. Among 3,825 pregnant women screened, dual HIV rapid testing indicated that 30.2% were HIV positive, 69.7% were HIV negative, and 0.1% were indeterminate. Sensitivity and specificity of dual rapid testing was 99.0% and 98.7%, respectively. Of 2,666 seronegative specimens, 2,327 had samples available for HIV RNA pooling; 5 women (0.21%) (95% confidence interval, 0.03–0.40%) had AHI with a median peripartum viral load of 1,324,766 copies/mL. Pregnant women are at risk for AHI, warr......
POSTED 03/12/2010 at 10:32 AM --
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New cfiA variant and novel insertion sequence elements in carbapenem-resistant Bacteroides fragilis isolates from Korea
This study reconfirmed the correlation between ISs and carbapenem resistance in B. fragilis. (Source: Diagnostic Microbiology and Infectious Disease)...
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Impact of bacterial colonization on the severity, and accompanying airway inflammation, of virus-induced wheezing in children
This study aimed to explore the impact of bacterial colonization on the severity of virus-induced wheezing, and accompanying airway inflammation. Nasopharyngeal aspirates (NPAs) from 68 hospitalized children with bronchiolitis and 85 children with recurrent wheezing were obtained. Eleven common respiratory viruses were sought by PCR and/or direct fluorescence assay. Bacteria were isolated from NPAs by routine culture methods. Cell numbers and concentrations of cytokines/chemokines in the NPAs were measured, and nucleated cells were characterized. The frequency of bacterial colonization in children with recurrent wheezing was significantly higher than in children with an initial attack of bronchiolitis. Bacterial colonization accompanying virus infection had no effect on clinical manifestat......
POSTED 03/11/2010 at 06:00 PM --
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Population dynamics of two antilisterial cheese surface consortia revealed by temporal temperature gradient gel electrophoresis
Conclusions:
This work reports the first population dynamics study of complex smear ecosystems exhibiting in situ antilisterial activity. TTGE revealed the presence of marine lactic acid bacteria that are likely related to the strong Listeria inhibition, as their early development in the smear occurred simultaneously with a decrease in Listeria cell count. (Source: BMC Microbiology - Latest articles)...
POSTED 03/10/2010 at 06:00 PM --
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γδ T cells promote the maturation of dendritic cells during West Nile virus infection
[gamma][delta] T cells are important for the early control of West Nile virus (WNV) dissemination. Here, we investigated the role of [gamma][delta] T cells in the regulation of CD4+ T-cell response following a WNV challenge. Splenic dendritic cells (DCs) of WNV-infected [gamma][delta] T-cell-deficient (TCR[delta][minus]/[minus]) mice displayed lower levels of CD40, CD80, CD86 and major histocompatibility complex (MHC) class II expression and interleukin-12 (IL-12) production than those of wild-type mice. Naïve DCs cocultured with WNV-infected [gamma][delta] T cells showed enhanced levels of costimulatory molecules, MHC class II expression and IL-12 production. Further, coculture of CD4+ T cells from OT II transgenic mice with DCs of WNV-infected TCR[delta][minus]/[minus] mice induced less......
POSTED 03/10/2010 at 06:00 PM --
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Identification of residues within ligand-binding domain 1 (LBD1) of the Borrelia burgdorferi OspC protein required for function in the mammalian environment
This study is the first to assess the involvement of individual residues and domains of OspC in its in vivo function. The data support the hypothesis that OspC interacts with a mammalian derived ligand that is critical for survival during early infection. These results shed new light on the structure[ndash]functions relationships of OspC and challenge existing hypotheses regarding OspC function in mammals. (Source: Molecular Microbiology)...
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Analysis of tRNA composition and folding in psychrophilic, mesophilic and thermophilic genomes: indications for thermal adaptation
Comparative genomic studies on several thermophilic archaea and bacteria revealed that a set of coordinated changes are associated with organisms adapted to a higher temperature, among which the dinucleotide composition of genomic DNA, pattern of codon usage and amino acid composition of the proteomes reveal subtle differences between thermophilic and mesophilic organisms. In this context, we have analyzed all tRNA sequences present in the complete genome sequences of 57 organisms belonging to psychrophiles, meophiles, thermophiles and hyperthermophiles. The presence of distinct selective constraints was revealed in the number and distribution of tRNAs and in their folding patterns, which could be correlated with the optimal growth temperature. The tRNA contents of thermophiles were found ......
POSTED 03/10/2010 at 06:00 PM --
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Common patterns – unique features: nitrogen metabolism and regulation in Gram-positive bacteria
Gram-positive bacteria have developed elaborate mechanisms to control ammonium assimilation, at the levels of both transcription and enzyme activity. In this review, the common and specific mechanisms of nitrogen assimilation and regulation in Gram-positive bacteria are summarized and compared for the genera Bacillus, Clostridium, Streptomyces, Mycobacterium and Corynebacterium, with emphasis on the high G+C genera. Furthermore, the importance of nitrogen metabolism and control for the pathogenic lifestyle and virulence is discussed. In summary, the regulation of nitrogen metabolism in prokaryotes shows an impressive diversity. Virtually every phylum of bacteria evolved its own strategy to react to the changing conditions of nitrogen supply. Not only do the transcription factors differ bet......
POSTED 03/10/2010 at 06:00 PM --
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Testate Amoebae from a Cretaceous Forest Floor Microbiocoenosis of France
ABSTRACT. Amber-preserved shells of testate amoebae often provide as many diagnostic features as the tests of modern taxa. Most of these well-preserved microfossils are morphologically assignable to modern species indicating either evolutionary stasis or convergent evolution. Here we describe two Lower Cretaceous testate amoebae that are clearly distinguishable from modern species. Centropyxis perforata n. sp. and Leptochlamys galippei n. sp. possessed perforate shells that were previously unknown in these genera. They are preserved in highly fossiliferous amber pieces from the Upper Albian (ca. 100 million years old) of Archingeay/Les Nouillers (Charente-Maritime, southwestern France). Syninclusions of soil and litter dwelling arthropods and microorganisms indicate a limnetic-terrestrial ......
POSTED 03/10/2010 at 06:00 PM --
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