323,075 research outputs found
Cluster analysis of antibiotic susceptibility patterns of clinical isolates as a tool in nosocomial infection surveillance.
No full textHospital infections represent a major epidemiological problem. The first step in the detection of nosocomial infections consists in assessing the probability that two or more isolates from different patients are similar or different. Many methods are available for typing purposes. Among these, antibiotic susceptibility patterns do not need extra cost or extra work and are available "on line" every moment they are needed. A mathematical technique of elaboration is proposed for disk zone sizes, in order to assess the probability of two or more clinical isolates to be the same strain. Antibiograms performed according to Kirby-Bauer are evaluated detecting zone sizes by a computer controlled device and then submitted to cluster analysis. Similarity of strains is reported in a dendrogram, in which strains are successively fused. Strains that share a common susceptibility pattern are considered a "cluster". At last, epidemiological maps are constructed for each group of strains, in which all the isolates are reported, ordered for patients, plotted on the day the specimen was collected, drawn in a different shape according to the source of specimen, and shadowed by the pattern of its cluster. This method of reporting data directly allows to detect cross infections among patients and can be used as a first typing step before other more expensive procedures
COMPETITIVE POLYMERASE CHAIN REACTION AND ANALYSIS OF VIRAL ACTIVITY AT THE MOLECULAR LEVEL
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Cluster analysis of antibiotic susceptibility patterns of clinical isolates as a tool in nosocomial infection surveillance.
No full textClinical, Diagnostic and Therapeutic Aspects of Implantable Cardiac Electronic Device Infections. A Five-Year Retrospective Analysis and Comparison with Literature.
No full textBackground: Infections related to implantable cardiac electronic devices (IICEDs) are increasing in incidence. Aim of our study was to evaluate: epidemiological characteristics, risk factors and type of device in patients who developed ICEDs compared to the control group; b. microbial causes and resistances; c. main signs and symptoms, laboratory and instrumental investigations; d. treatment and prognosis.
Material and Methods: the study was conducted with a retrospective method, analysing all cases of IICEDs registered in our ward from April 2009 to May 2014. For each patient, were evaluated epidemiological and clinical characteristics, risk factors, diagnostic procedures, aetiology and antibiotic assays, treatment and outcome.
Results: In the investigated period, 22 cases of IICEDs were registered. Demographic factors didn’t affect the risk of ICEDs. Hypertension, usually considered a risk factor, resulted to be a protective factor (p=0.0329). Age younger than 65 years, female gender, altered BMI, diabetes, dyslipidemia and smoking appear to increase the risk of IICEDs, although not significantly. The oral anticoagulant therapy was found to be a predictive negative factor (p=0.0012) as well as the type of implanted device, with particular regard to intracardiac defibrillator and biventricular devices. CoNS were isolated in 68% of cases, Staphylococcus aureus in 25% and Enterococcus faecalis in 3.5%. A polimicrobial aetiology was registered in one case (3.5%).
Among the CoNS, S. epidermidis was the most represented (28.55%), followed by S. hominis (14.3%) and S. haemoliticus (14.7%). The antibiotic assays showed a high proportion of methicillin resistance (34.8%) mainly related to S. epidermidis (71.4%) followed by S. aureus (14.3%). Rifampicin was found to be resistant in 8 cases (100%) by susceptibility testing. The treatment of ICEDs showed an important heterogeneity and a very long time waiting (12.22 months) between the diagnosis and the removal of the device. Of the 22 treated patients 7 died; 3 of them were older than 90 years while 4 were aged between 61 to 68 years.
Conclusion: young age, smoking and altered BMI are factors associated to the development of IICEDs, even if not statistically significant. Hypertension resulted a statistically protective factor. The suspension of oral anticoagulation therapy and assumption of perioperative heparin was found to be statistically associated with the risk of IICEDs development, because it increases the risk of hematoma formation. According to literature data, the majority of the isolated microorganisms were Staphylococci (68% CoNS and 25% S. aureus) with high rates of methicillin (34.8%) and rifampicin (100%) resistance. The difference between systemic infections and infections localized to the generator pocket is not easily distinguishable, confirming the therapeutic need of the device removal in case of infection
Genotypic and phenotypic correlates of the HIV type 1 env gene evolution in infected children with discordant response to antiretroviral therapy
No full textThe genotypic - phenotypic correlates of human immunodeficiency virus type 1 (HIV-1) env gene evolution were investigated in samples from eight infected children under antiretroviral therapy (ART) and virological failure. Evolution of the gp120 C2 - V5 env sequence was demonstrated in all subjects but one by sequence analysis of the replicating plasma virus collected at baseline and 12 - 15 months after ART initiation. The analysis of the host's selective pressure showed that in four subjects, the ratio of nonsynonymous to synonymous amino acid substitutions was higher in the V3 sequences than in the C2 - V5 region ([K-a/K-s](V3)/[K-a/K-s](C2-V5) > 1.0). Interestingly, this feature was observed only in subjects ( four of five) showing an increase in T cell receptor rearrangement excision circle (TREC)-bearing cells and in CD4(+) T-lymphocytes despite persistent viremia ( discordant therapeutic response) ( p = 0.02), thus suggesting that the V3 loop is a target of the immune reconstitution under ART. Using phenotypic analysis of recombinant viruses expressing exogenous V3 sequences, a reverse shift from CXCR4-tropic to CCR5-tropic variants was demonstrated in two of the four subjects, further indicating that the host's selective pressure sharply forces the V3 evolution of replicating variants. The data indicate that a complex HIV-1 - host interplay occurs in children receiving antiretroviral treatments and suggest that the recovery of thymic function places a selective constraint on the viral V3 loop
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