113 research outputs found
Reply to letter to editor: Efficacy of anti-retraction devices in preventing bacterial contamination of dental unit water lines
A KLUYVERA-CRYOCRESCENS STRAIN FROM A GALLBLADDER INFECTION
The isolation and the identification of a pure-culture Kluyvera cryocrescens
strain in a gall.bladder pus specimen from a 76-year-old woman vcith acute cholecystitis
is described. This is the first Teported recovery of a K. cryocrescens
strain from such a sample
Efficacy of acoustic waves in preventing Streptococcus mutans adhesion on dental unit water line
Background: nei riuniti odontoiatrici, la qualità dell'acqua utilizzata per la refrigerazione e il risciacquo di manipoli, siringhe e altri componenti è un aspetto di notevole importanza sanitaria. L'acqua attraversa questi dispositivi mediante un circuito interconnesso di tubi di piccole dimensioni (circa 2 mm di diametro), denominato “dental unit water line” (DUWL). I DUWL possono essere fortemente colonizzati da varie specie batteriche sia in fase planctonica, che adesi o organizzati in biofilm, rappresentando una potenziale causa di infezione, non solo per i professionisti che usano abitualmente questi dispositivi, ma anche per pazienti occasionali, in particolare per i pazienti immunocompromessi. La contaminazione dei DUWL può essere prevenuta o ridotta con l'uso dei disinfettanti, ma l'eradicazione dei microrganismi adesi alle superfici interne dei DUWL o organizzati in forma di biofilm, è una sfida assai più complessa e spesso i normali metodi di disinfezione non sono pienamente efficaci. Inoltre, in ambito odontoiatrico, i disinfettanti utilizzati abitualmente per disinfettare i DUWL possono alterare la capacità adesiva del materiale utilizzato nella pratica restaurativa.
Obiettivi: individuare una strategia innovativa, in grado di contrastare l'adesione batterica alle superfici dei DUWL mediante un approccio di tipo fisico, che sia più efficace nel superare il problema della contaminazione dei DUWL e ridurre il rischio di infezione rispetto ai normali metodi già in uso. A tal fine, fra le molte specie batteriche potenzialmente riscontrabili nei circuiti idrici odontoiatrici, si è deciso di avviare questo studio pilota utilizzando la specie batterica patogena S. mutans, per il suo indubbio interesse in ambito odontoiatrico e per la sua spiccata capacità di aderire e persistere su superfici inerti.
Metodi: utilizzo di onde acustiche elastiche ad alta energia nel contrastare l'adesione di Streptococcus mutans alle pareti interne di un circuito idrico sperimentale riproducente un DUWL. Per evidenziare l’efficacia delle onde acustiche anche in condizioni estreme, è stata utilizzata un’elevata carica contaminante di S. mutans.
Risultati: Si osserva una significativa riduzione dei batteri adesi soggetti a trattamento con onde acustiche rispetto al controllo (P = 0,003)
NEW PLATE MEDIUM FOR SCREENING AND PRESUMPTIVE IDENTIFICATION OF GRAM-NEGATIVE URINARY-TRACT PATHOGENS
A new selective, differential plating medium to screen the common gram-negative urinary tract pathogens is
described. The medium combines adonitol fermentation, phenylalanine deaminase, and P-glucuronidase tests
and allows the indole and cytochrome oxidase tests to be performed directly from the plates. High-level
agreement with individual conventional tests was recorded in comparative studies with 504 cultures of
gram-negative rods. There was 100% agreement, except for the Providencia spp. indole spot test (61.6%
agreement). Adonitol fermentation by Providencia species could not be determined. Escherichia coli, Klebsiella
pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa were identified with a high efficiency (100, 85.7,
83.5, and 100% agreement, respectively) without further testing. There was 96% overall agreement for the 267
infected urine samples tested
T-MOD PATHWAY, A REDUCED SEQUENCE FOR IDENTIFICATION OF GRAM-NEGATIVE URINARY-TRACT PATHOGENS
In this paper, we describe a reduced sequence of identification that includes T-mod medium, a selective and
differential isolation medium which allows accurate presumptive identification of the most common gramnegative
bacteria encountered in urine samples. The present study, performed on bacteria isolated from 1,762
independent urine samples, has shown that a few selected tests (lysine and ornithine decarboxylase, urease and
trehalose fermentation tests) improve the identification accuracy of T-mod, making it possible both to identify
the less frequent species and to prevent some misidentifications of Klebsiella pneumoniae and Proteus mirabilis.
The proposed work flow agreed with conventional identification protocols to a 99.3% extent and allowed
identification of 87.4% of the isolates directly from the primary plate, 11.4% after 1 to 3 additional tests, and
1.2% after an identification gallery
Characterization and sequence of PhoC, the principal phosphate-irrepressible acid phosphatase of Morganella morganii.
Phosphatase activities were investigated in Morganella morganii, which is one
of the few enterobacterial species producing high-level phosphateirrepressible
acid phosphatase activity (HPAP phenotype), and the gene
encoding the major phosphate-irrepressible acid phosphatase was cloned,
sequenced, and its product characterized. Using p-nitrophenyl phosphate as
substrate, Morganella produced a major phosphate-irrepressible acid
phosphatase (named PhoC) which is associated with the HPAP phenotype, a
minor phosphate-irrepressible acid phosphatase, and a phosphate-repressible
alkaline phosphatase. The presence of the PhoC activity prevented induction of
alkaline phosphatase when a PhoC-hydrolysable organic phosphate ester, such
as glycerol &phosphate, was the sole phosphate source. PhoC is a secreted
nonspecific acid phosphatase apparently composed of four 25 kDa polypeptide
subunits. The enzyme is resistant to EDTA, Pi# fluoride and tartrate. The M.
morganii PhoC showed 84.6% amino acid sequence identity to the PhoN
nonspecific acid phosphatase of Providencia stuartii, 45.3 O/O to the PhoN
nonspecific acid phosphatase of Salmonella typhimurium, and 3708% to the
principal acid phosphatase (PhoC) of Zymomonas mobilis. Comparison of
sequence data and of regulation of these enzymes suggested a different
phylogeny of members of this gene family within the Enterobacteriaceae
Biotimer assay: A reliable and rapid method for the evaluation of central venous catheter microbial colonization
Adherent bacteria and biofilm frequently colonize central venous catheters (CVCs). CVC colonization is correlated
to infections and particularly to bloodstream ones. The classical microbiological methods to determine of
CVC colonization are not fully reliable and are time-consuming. BioTimer Assay (BTA) is a biological method
already used to count bacteria adherent to abiotic surfaces and biofilm without sample manipulation. BTA
employs specific reagents whose color changed according to bacterial metabolism. BTA is based on the principle
that a metabolic reaction will be faster when more bacteria are present in the sample. Therefore, the time
required for color changes of BTA reagents determines the number of bacteria present in the sample through a
correlation line. Here, for the first time, we applied BTA and a specifically developed laboratory procedure to
evaluate CVC colonization in comparison with the routine microbiological method (RMM). 125 CVCs removed
from patients for suspected catheter-related bloodstream infection (CRBSI) or at hospital discharge were examined.
BTA was reliable in assessing sterility and CVC colonization (100% agreement with RMM) and in
recognizing the presence of fermenting or non-fermenting bacteria (97.1% agreement with RMM) shortening the
analytical time by between 2- and 3-fold. Moreover, the reliability of BTA as early alert of CRBSI was evaluated.
The sensitivity, specificity, positive, and negative predictive values for BTA as an early alert of CRBSI were 100,
40.0, 88.8 and 100%, respectively.
In conclusion, BTA and the related laboratory procedure should be incorporated into routine microbiological
methods since it can be considered a reliable tool to evaluate CVC colonization in a very short time and a rapid
alert for CRBSIs
Effect of bovine lactoferrin on chlamydia trachomatis infection and inflammation.
Chlamydia trachomatis is an obligate, intracellular pathogen responsible for the most common sexually transmitted bacterial disease worldwide, causing acute and chronic infections. The acute infection is susceptible to antibiotics, whereas the chronic one needs prolonged therapies, thus increasing the risk of developing antibiotic resistance. Novel alternative therapies are needed. The intracellular development of C. trachomatis requires essential nutrients, including iron. Iron-chelating drugs inhibit C. trachomatis developmental cycle. Lactoferrin (Lf), a pleiotropic iron binding glycoprotein, could be a promising candidate against C. trachomatis infection. Similarly to the efficacy against other intracellular pathogens, bovine Lf (bLf) could both interfere with C. trachomatis entry into epithelial cells and exert an anti-inflammatory activity. In vitro and in vivo effects of bLf against C. trachomatis infectious and inflammatory process has been investigated. BLf inhibits C. trachomatis entry into host cells when incubated with cell monolayers before or at the moment of the infection and down-regulates IL-6/IL-8 synthesized by infected cells. Six out of 7 pregnant women asymptomatically infected by C. trachomatis, after 30 days of bLf intravaginal administration, were negative for C. trachomatis and showed a decrease of cervical IL-6 levels. This is the first time that the bLf protective effect against C. trachomatis infection has been demonstrated
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