Identification of resistance in Escherichia coli and Klebsiella pneumoniae using excitation-emission matrix fluorescence spectroscopy and multivariate analysis.

Klebsiella pneumoniae and Escherichia coli are part of the Enterobacteriaceae family, being common sources of community and hospital infections and having high antimicrobial resistance. This resistance profile has become the main problem of public health infections. Determining whether a bacterium has resistance is critical to the correct treatment of the patient. Currently the method for determination of bacterial resistance used in laboratory routine is the antibiogram, whose time to obtain the results can vary from 1 to 3 days. An alternative method to perform this determination faster is excitation-emission matrix (EEM) fluorescence spectroscopy combined with multivariate classification methods. In this paper, Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA) and Support Vector Machines (SVM), coupled with dimensionality reduction and variable selection algorithms: Principal Component Analysis (PCA), Genetic Algorithm (GA), and the Successive Projections Algorithm (SPA) were used. The most satisfactory models achieved sensitivity and specificity rates of 100% for all classes, both for E. coli and for K. pneumoniae. This finding demonstrates that the proposed methodology has promising potential in routine analyzes, streamlining the results and increasing the chances of treatment efficiency.

Use of maggot therapy for treating a diabetic foot ulcer colonized by multidrug resistant bacteria in Brazil.

This study reports the efficacy of maggot therapy in the treatment of diabetic foot ulcer infected with multidrug resistant microorganisms. A 74 year old female patient with diabetes for over 30 years, was treated with maggot therapy using larvae of Chrysomya megacephala. The microbiological samples were collected to evaluate aetiology of the infection. The therapy done for 43 days resulted in a reduction of necrosis and the ulcer's retraction of 0.7 cm [2] in area. Analysis of the bacteriological swabs revealed the presence of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. Further studies need to be done to confirm the role of maggot therapy in wound healing using a large sample and a proper study design.

Rapid discrimination of Klebsiella pneumoniae carbapenemase 2-producing and non-producing Klebsiella pneumoniae strains using near-infrared spectroscopy (NIRS) and multivariate analysis.

Klebsiella pneumoniae Carbapenemase (KPC-2)-producing and non-producing Klebsiella pneumoniae (KP) have rapidly disseminated worldwide, challenging the diagnostics of Gram-negative infections. We evaluate the potential of a novel non-destructive and rapid method based on Near-Infrared Spectroscopic (NIRS) and multivariate analysis for distinguishing KPC-2-producing and non-producing KP. Thirty-nine NIRS spectra (24 KPC-2-producing KP, 15 KPC-2 non-producing KP) were acquired; different pre-processing methods such as baseline correction, derivative and Savitzky-Golay smoothing were performed. A spectral region fingerprint was achieved after using genetic algorithm-linear discriminant analysis (GA-LDA) and successive projection algorithm (SPA-LDA) algorithms for variable selection. The variables selected were then used for discriminating the microorganisms.Accuracy test results including sensitivity and specificity were determined. Sensitivity in KPC-2 producing and non-producing KP categories was 66.7% and 75%, respectively, using a SPA-LDA model with 66 wavenumbers. The resulting GA-LDA model successfully classified both microorganisms with respect to their "fingerprints" using only 39 wavelengths. Sensitivity in KPC-2 producing category was moderate(≈66.7%) using a GA-LDA model. However, sensitivity in KPC-2 non-producing category using GA-LDA accurately predicted the correct class (with 100% accuracy). As100% accuracy was achieved, this novel approach identifies potential biochemical markers that may have a relation with microbial functional roles and means of rapid identification of KPC-2 producing and non-producing KP strains.

[Diabetic foot infection. Bacteriologic analysis of 141 patients]. / Pé diabético: análise bacteriológica de 141 casos.

Diabetes mellitus (DM) is a progressive disease with chronic complications. Feet problems represent one of the most important complications. In a prospective study, we analyzed 298 species of bacteria isolated from 141 patients with community-acquired diabetic foot ulcers. The study was undertaken at a diabetic center and at the Federal University of Ceará, Brazil, from March/2000 to November/2001. The majority of patients had mild to moderate infections and was classified as Wagner's grades I and II. The samples were cultured using selective media. The identification and the susceptibility tests were done by conventional and automated methods. The most frequently occurring pathogens were Enterobacteriaceae (83.7%), Staphylococcus aureus (43.3%) and anaerobic bacteria (17%). Streptococcus pyogenes was recovered from 7.8% of the patients. ESBL producing strains were detected in 6% and methicillin resistant Staphylococcus aureus strains were recovered from 11.6% of the patients. Resistance among bacteria has increased largely, and became common even in community-acquired infections. Improvements in the routine etiologic diagnostics and antibiotic use strategies are required to avoid inadequate treatment and its well known dramatic consequences.