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1.
Phys Rev Lett ; 132(9): 091901, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38489625

ABSTRACT

We perform the first global quantum chromodynamics (QCD) analysis of dihadron production for a comprehensive set of data in electron-positron annihilation, semi-inclusive deep-inelastic scattering, and proton-proton collisions, from which we extract simultaneously the transversity distributions of the nucleon and π^{+}π^{-} dihadron fragmentation functions. We incorporate in our fits known theoretical constraints on transversity, namely, its small-x asymptotic behavior and the Soffer bound. We furthermore show that lattice-QCD results for the tensor charges can be successfully included in the analysis. This resolves the previously reported incompatibility between the tensor charges extracted from dihadron production data and lattice QCD. We also find agreement with results for the transversity and tensor charges obtained from measurements on single-hadron production. Overall, our work demonstrates for the first time the universal nature of all available information for the transversity distributions and the tensor charges of the nucleon.

2.
Phys Rev Lett ; 132(1): 011902, 2024 Jan 05.
Article in English | MEDLINE | ID: mdl-38242654

ABSTRACT

We present a new quantum field-theoretic definition of fully unintegrated dihadron fragmentation functions (DiFFs) as well as a generalized version for n-hadron fragmentation functions. We demonstrate that this definition allows certain sum rules to be satisfied, making it consistent with a number density interpretation. Moreover, we show how our corresponding so-called extended DiFFs that enter existing phenomenological studies are number densities and also derive their evolution equations. Within this new framework, DiFFs extracted from experimental measurements will have a clear physical meaning.

3.
Phys Rev Lett ; 127(24): 242001, 2021 Dec 10.
Article in English | MEDLINE | ID: mdl-34951781

ABSTRACT

We report the results of a Monte Carlo global QCD analysis of unpolarized parton distribution functions (PDFs), including for the first time constraints from ratios of ^{3}He to ^{3}H structure functions recently obtained by the MARATHON experiment at Jefferson Lab. Our simultaneous analysis of nucleon PDFs and nuclear effects in A=2 and A=3 nuclei reveals the first indication for an isovector nuclear EMC effect in light nuclei. We find that while the MARATHON data yield relatively weak constraints on the F_{2}^{n}/F_{2}^{p} neutron to proton structure function ratio and on the d/u PDF ratio, they suggest an enhanced nuclear effect on the d-quark PDF in the bound proton, questioning the assumptions commonly made in nuclear PDF analyses.

4.
J Clin Virol ; 107: 52-56, 2018 10.
Article in English | MEDLINE | ID: mdl-30195193

ABSTRACT

BACK GROUND: Systematic reviews have concluded that hrHPV DNA testing using target-amplification tests is as accurate on vaginal self-samples as on clinician-taken specimens for the detection of cervical precancer. However, insufficient evidence is available for specific HPV assay/self-sample device combinations. OBJECTIVES: The VALHUDES protocol is designed as a diagnostic test accuracy study that aims to compare the clinical sensitivity and specificity of particular hrHPV assay(s) on vaginal self-samples and first-void-urine, collected in agreement with standardized protocols, with hrHPV testing on matched clinician-taken samples. STUDY DESIGN: Five hundred enrolled women referred to a colposcopy clinic are invited to collect a first-void urine sample and one or more vaginal self-samples with particular devices before collection of a cervical sample by a clinician. Sample sets are subsequently analysed in a laboratory accredited for HPV testing. Disease verification for all enrolled patients is provided by colposcopy combined with histological assessment of biopsies. RESULTS: A first VALHUDES study has started in Belgium in December 2017 with enrolment from four colposcopy centres. The following assays are foreseen to be evaluated: RealTime High Risk HPV assay (Abbott), cobas-4800 and -6800 (Roche), Onclarity (BD), Xpert HPV (Cepheid) and Anyplex II HPV HR (Seegene). CONCLUSION: Given empirical evidence that the relative accuracy of HPV-testing on self- vs clinician-samples is robust across clinical settings, the VALHUDES protocol offers a framework for validation of HPV assay/self-sample device combinations that can be translated to a primary screening setting.


Subject(s)
Early Detection of Cancer/methods , Papillomaviridae/isolation & purification , Papillomavirus Infections/diagnosis , Papillomavirus Infections/urine , Specimen Handling/methods , Adult , Belgium , Cervix Uteri/virology , Colposcopy , DNA, Viral/genetics , DNA, Viral/isolation & purification , Early Detection of Cancer/instrumentation , Female , Humans , Mass Screening/methods , Middle Aged , Papillomaviridae/genetics , Reproducibility of Results , Sensitivity and Specificity , Specimen Handling/instrumentation , Urine Specimen Collection/instrumentation , Urine Specimen Collection/methods , Uterine Cervical Neoplasms/diagnosis , Uterine Cervical Neoplasms/virology , Vagina/virology , Uterine Cervical Dysplasia/diagnosis , Uterine Cervical Dysplasia/virology
5.
J Hosp Infect ; 99(4): 413-418, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29621600

ABSTRACT

AIM: To describe the phenotypic and genotypic profiles of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) strains isolated from patients with invasive infections at an Italian university hospital in order to assess the epidemiological trend. METHODS: An observational prospective study was undertaken at the University Hospital of Sassari, Italy to detect KPC-Kp strains in patients with invasive bacteraemia. Isolates were identified phenotypically; carbapenemase production was assessed using phenotypic and genotypic methods. Sequencing of blaKPC genes, pulsed-field gel electrophoresis and multi-locus sequence typing were performed. RESULTS: During the period 2015-2017, 46 cases of invasive infection with K. pneumoniae were recorded. Two-thirds (67.4%) of the patients were male, and the mean age was 69.4 years. Most patients had at least one comorbidity (56.5%) and/or had been hospitalized previously (70.5%), 81.8% had current or recent medical device use, and 85.4% had recent antibiotic exposure. The mortality rate was 52.3%. A multi-drug-resistant pattern (including carbapenems, fluoroquinolones, third-/fourth-generation cephalosporins) was shown for all K. pneumoniae isolates. KPC-3 and -2 were produced by all strains. The most common sequence types were 512 (91.3%) and 101 (8.7%), grouped into three clusters (A, A1 and B). CONCLUSIONS: A high incidence of KPC-Kp in patients with invasive infections was recorded at an Italian university hospital compared with the incidence measured before 2015. This study confirmed the importance of the KPC-3 carbapenemase variant, as reported by other Italian studies. High mortality and comorbidity rates appear to be associated with KPC-Kp infection.


Subject(s)
Bacteremia/transmission , Carbapenem-Resistant Enterobacteriaceae/isolation & purification , Cross Infection/transmission , Disease Transmission, Infectious , Genotype , Klebsiella Infections/transmission , Klebsiella pneumoniae/isolation & purification , Aged , Aged, 80 and over , Anti-Bacterial Agents/pharmacology , Bacteremia/epidemiology , Bacteremia/microbiology , Bacteremia/mortality , Carbapenem-Resistant Enterobacteriaceae/classification , Carbapenem-Resistant Enterobacteriaceae/genetics , Cross Infection/epidemiology , Cross Infection/microbiology , Cross Infection/mortality , Drug Resistance, Multiple, Bacterial , Electrophoresis, Gel, Pulsed-Field , Female , Hospitals, University , Humans , Incidence , Italy/epidemiology , Klebsiella Infections/epidemiology , Klebsiella Infections/microbiology , Klebsiella Infections/mortality , Klebsiella pneumoniae/classification , Klebsiella pneumoniae/genetics , Male , Microbial Sensitivity Tests , Middle Aged , Molecular Epidemiology , Multilocus Sequence Typing , Prospective Studies , Sequence Analysis, DNA , Survival Analysis
6.
J Antimicrob Chemother ; 72(2): 372-375, 2017 02.
Article in English | MEDLINE | ID: mdl-27798212

ABSTRACT

BACKGROUND: MRSA is a therapeutic concern worldwide, and a major agent of community-acquired skin and soft tissue infections (CA-SSTIs). While the US epidemiology of MRSA in CA-SSTIs is well described and reports the high prevalence of the USA300 clone, data on the European situation are lacking. OBJECTIVES: To determine the prevalence and clonal characteristics of MRSA in CA-SSTIs in seven European emergency departments. PATIENTS AND METHODS: From April to June 2015, patients presenting to the tertiary hospital emergency department with a Staphylococcus aureus CA-SSTI were prospectively enrolled. S. aureus isolates were characterized by antimicrobial susceptibility testing, detection of Panton-Valentine leucocidin encoding genes and spa-typing, MLST and/or DNA microarray. RESULTS: Two-hundred and five cases of S. aureus-associated CA-SSTIs were included, comprising folliculitis, furuncles, abscesses, paronychia, impetigo, carbuncles and cellulitis. Of the 205 cases, we report an MRSA prevalence rate of 15.1%, with a north (0%) to south (29%) increasing gradient. Fifty-one isolates were Panton-Valentine leucocidin-positive (24.9%), whether MSSA or MRSA, with a heterogeneous distribution between countries. Clonal distribution of MSSA and MRSA showed high diversity, with no predominant circulating clone and no archetypical USA300 CA-MRSA clone. CONCLUSIONS: This original prospective multicentre study highlights stark differences in European MRSA epidemiology compared with the USA, and that the USA300 CA-MRSA clone is not predominant among community-infected patients in Europe.


Subject(s)
Community-Acquired Infections/epidemiology , Emergency Service, Hospital , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Soft Tissue Infections/epidemiology , Staphylococcal Infections/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Bacterial Toxins/genetics , Child , Child, Preschool , Community-Acquired Infections/microbiology , Europe/epidemiology , Exotoxins/genetics , Female , Genotype , Humans , Infant , Leukocidins/genetics , Male , Methicillin-Resistant Staphylococcus aureus/classification , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/genetics , Microarray Analysis , Microbial Sensitivity Tests , Middle Aged , Molecular Epidemiology , Multilocus Sequence Typing , Oligonucleotide Array Sequence Analysis , Prevalence , Prospective Studies , Soft Tissue Infections/microbiology , Staphylococcal Infections/microbiology , Staphylococcal Protein A/genetics , Tertiary Care Centers , Young Adult
7.
J Chemother ; 22(3): 153-9, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20566418

ABSTRACT

The aim of this study was to evaluate the in vitro antibiotic susceptibility of respiratory pathogens recently isolated in Italy to commonly used antibiotics including cefditoren. Six clinical microbiological laboratories collected, between January and September 2009, a total of 2,510 respiratory pathogens from subjects with community-acquired respiratory tract infections (CARTI). Ceftditoren, out of all the beta-lactams studied, had the lowest MIC(90 )against 965 strains of Streptococcus pneumoniae examined, followed by cefotaxime and ceftriaxone (2% resistance in penicillin-resistant S. pneumoniae (PRSP)). Against 470 Haemophilus influenzae , independently of their production of beta-lactamases or ampicillin resistance, cefditoren was the oral cephalosporin with the best in vitro activity, comparable to that of the injectable cephalosporins and levofloxacin. Higher MIC(90)s were found for the macrolides (4 - 16 mg/l) and cefaclor (4 - 32 mg/l). As was foreseeable, Streptococcus pyogenes (225 strains) was uniformly sensitive to all the beta-lactam antibiotics, but the elevated MIC(90 )values reduced (<75%) susceptibility of this pathogen to macrolides. Beta-lactamase-negative Moraxella catarrhalis (100 strains) had reduced susceptibility only to the macrolides, while the 250 beta-lactamase-producing strains also had reduced susceptibility to cefuroxime. Levofloxacin showed the lowest MIC(50)/MIC(90 )values in the producing strains, whereas cefditoren, cefotaxime and ceftriaxone in the non-producers. As regards the enterobacteriaceae, cefditoren and levofloxacin had the lowest MIC(90)s against Klebsiella pneumoniae. Cefditoren and the third-generation injectable cephalosporins had the lowest MIC(90)s against Escherichia coli (100% susceptibility) while levofloxacin was less active (86% susceptibility).In conclusion, cefditoren's wide spectrum and high intrinsic activity, as well as its capacity to overcome most of the resistance that has become consolidated in some classes of antibiotics widely used as empiric therapy for CARTI, allows us to suggest that cefditoren might be included in the european guidelines as one of the first-choice antibiotics in the treatment of CARTI.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cephalosporins/pharmacology , Community-Acquired Infections/microbiology , Gram-Negative Bacteria/drug effects , Gram-Negative Bacterial Infections/microbiology , Respiratory Tract Infections/microbiology , Gram-Negative Bacteria/isolation & purification , Humans , Italy , Microbial Sensitivity Tests
8.
J Med Virol ; 80(1): 147-53, 2008 Jan.
Article in English | MEDLINE | ID: mdl-18041029

ABSTRACT

Human papillomaviruses (HPVs) are necessary, but not sufficient, for the development of cervical cancer (CC). Human beta-herpesviruses (beta-HHVs) have been suggested as possible cofactors in the oncogenesis of CC. In this cross-sectional study, the prevalence and possible association of cytomegalovirus (CMV), HHV-6 and -7 with HPV presence was investigated by quantitative real-time PCR assays in cervical samples obtained from 208 italian women. The two most common high-risk HPV types found were 31 and 16. Overall, the positive rates for CMV, HHV-6 and HHV-7 were 66%, 25%, and 6%, respectively. In particular, the prevalence of CMV was found to be extremely high irrespective of either the cytological category or HPV positivity. The prevalence of HHV-6 DNA was significantly higher in high-grade squamous intraepithelial lesions (HSIL) respect to normal women (P < 0.017); by contrast, the prevalence HHV-7 DNA was generally low and not associated with SIL. Copresence of CMV and HHV-6 DNA was found to be significantly higher in patients with SIL respect to normal women (P < 0.05). No correlation was demonstrated between the viral load of all three beta-HHVs and the different cytological stages or with the HPV presence. A few patients with severe disease however showed very high viral loads which for HHV-6 may be indicative of viral integration. In conclusion, this study suggests that CMV and HHV-7 alone are probably not implicated in the oncogenesis of CC whilst HHV-6 alone or together with CMV may contribute to the development of CC.


Subject(s)
Cell Transformation, Neoplastic , Cytomegalovirus Infections/epidemiology , Cytomegalovirus/isolation & purification , Herpesviridae Infections/epidemiology , Herpesvirus 7, Human/isolation & purification , Uterine Cervical Neoplasms/virology , Animals , Cell Transformation, Viral , Cervix Uteri/pathology , Chlorocebus aethiops , Cross-Sectional Studies , Cytomegalovirus/pathogenicity , Cytomegalovirus Infections/virology , DNA, Viral , Female , Herpesviridae Infections/virology , Humans , Polymerase Chain Reaction , Uterine Cervical Neoplasms/pathology , Vero Cells
9.
G Chir ; 28(4): 139-41, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17475114

ABSTRACT

Pyogenic abscess of the psoas muscle is a rare disease. The Authors report a recently observed case which developed 10 years after ipsilateral nephrectomy for pyonephrosis, reviewing the pertinent literature. The culture of the pus extracted only reproduced Proteus mirabilis. The relation between psoas abscess and nephrectomy is unclear. To make diagnosis is important to consider this condition in differential diagnosis in presence of fever and flank tenderness in a nephrectomized patient.


Subject(s)
Nephrectomy/adverse effects , Nephrectomy/methods , Proteus Infections/etiology , Proteus mirabilis , Psoas Abscess/etiology , Pyonephrosis/surgery , Aged , Female , Humans , Time Factors
10.
G Chir ; 27(6-7): 269-71, 2006.
Article in Italian | MEDLINE | ID: mdl-17062198

ABSTRACT

The Authors present 2 cases of enterobiasis of appendix observed on a total of 186 appendicectomies. Enterobius infestation is an uncommon cause of acute appendicitis. Preoperative diagnosis of pinworm infestation is almost impossible without clinical suspect. Parasites may produce symptoms which resemble acute appendicitis but parasitic infection rarely causes it. It is also important considered in the differential diagnosis cases that mimic Crohn's disease.


Subject(s)
Appendix , Cecal Diseases , Enterobiasis , Intestinal Diseases, Parasitic , Adult , Animals , Appendectomy , Cecal Diseases/diagnosis , Cecal Diseases/surgery , Diagnosis, Differential , Enterobiasis/diagnosis , Enterobiasis/surgery , Enterobius/isolation & purification , Female , Humans , Intestinal Diseases, Parasitic/diagnosis , Intestinal Diseases, Parasitic/surgery
11.
Microb Drug Resist ; 10(3): 264-8, 2004.
Article in English | MEDLINE | ID: mdl-15383172

ABSTRACT

The prevalence of the internalization-associated prtF1 gene was studied in 837 isolates of Streptococcus pyogenes obtained from 713 pediatric patients presenting with acute pharyngotonsillitis before and after antibiotic therapy. Its association with macrolide resistance and with bacteriological treatment failure was determined. The bacterial population isolated from baseline pharyngeal swabs showed an overall prtF1 positivity rate of 33%. A higher prtF1 positivity was found among erythromycin-resistant strains (45%) showing, however, marked differences between the inducible (iMLS), constitutive (cMLS), and efflux pump (M) resistance phenotypes. The prevalence was statistically higher (p < 0.001) in strains belonging to iMLS (84%) and cMLS (67%) phenotypes as compared to the M phenotype (15%). Interestingly, the prevalence of the prtF1 gene was significantly lower (p = 0.04) in strains belonging to M resistance phenotype as compared to erythromycin-susceptible strains (28%). Failed bacterial eradication was demonstrated in 124 patients. The prtF1 positivity rate remained unchanged in strains isolated before and after therapy in patients treated with macrolides (9/54). On the other hand, the positivity rate for the prtF1 gene was significantly higher (p = 0.015) in strains isolated after therapy with beta-lactams (21/70) as compared to baseline isolates (6/70), indicating a differential selection imposed on the organism by these agents. Finally, a high overall eradication rate (88%) of prtF1-positive isolates, belonging to both the erythromycin-susceptible and -resistant phenotypes, was demonstrated following macrolide treatment.


Subject(s)
Adhesins, Bacterial/genetics , Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial , Pharyngitis/microbiology , Streptococcus pyogenes/genetics , Tonsillitis/microbiology , Acute Disease , Anti-Bacterial Agents/therapeutic use , Child , Erythromycin/pharmacology , Erythromycin/therapeutic use , Humans , Microbial Sensitivity Tests , Pharyngitis/drug therapy , Polymerase Chain Reaction , Streptococcus pyogenes/drug effects , Streptococcus pyogenes/isolation & purification , Tonsillitis/drug therapy , Treatment Failure , beta-Lactams/pharmacology , beta-Lactams/therapeutic use
12.
G Chir ; 23(10): 369-71, 2002 Oct.
Article in Italian | MEDLINE | ID: mdl-12611257

ABSTRACT

Spigelian hernia is a rare condition of the abdominal wall; 13 cases occurred in the last five years are here reported. These patients were treated surgically, using direct reconstruction of the abdominal wall in eight cases, while a tension-free hernioplasty was utilized in five cases.


Subject(s)
Hernia, Ventral/surgery , Surgical Mesh , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Treatment Outcome
13.
Int J Antimicrob Agents ; 18(1): 9-17, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11463521

ABSTRACT

A total of 123 community paediatricians and 23 microbiology laboratories studied the clinical and bacteriological efficacy of treatment of group A streptococcal pharyngitis in Italy. Of 1065 patients, from whom Streptococcus pyogenes was isolated, 723 returned to follow up and of these 138 (19%) still had a positive throat culture. The erythromycin resistance (ER) rate was 23.7% with resistance phenotype distribution of: 31.7% constitutive (CR), 26.6% inducible (IR) and 41.7% efflux pump (M) resistance phenotype. All strains were susceptible to the beta-lactam agents tested. CR strains were highly resistant to all 14, 15 and 16 membered macrolides with the exception of rokitamycin which showed activity against 37.8% of isolates. All phenotype M and some IR isolates were susceptible to clindamycin, rokitamycin, josamycin and spiramycin; clarithromycin was active against a small percentage of strains belonging to the IR and M phenotype. Bacterial eradication was found in 85.5, 78.7 and 75.8% of the penicillin, macrolide and cephalosporin treated groups. Genotyping of strains showed that 8.7% of the 19% of cases classified as 'failed bacterial eradication' were due to recolonization with a different isolate, observed exclusively among beta-lactams treated patients. Clinical cure was achieved in a high percentage of cases, irrespective of the antibiotic prescribed, with the best clinical efficacy being found following therapy with amoxycillin and clarithromycin (90.9%).


Subject(s)
Anti-Bacterial Agents/therapeutic use , Pharyngitis/drug therapy , Pharynx/microbiology , Streptococcal Infections/drug therapy , Streptococcus pyogenes/drug effects , Adolescent , Anti-Bacterial Agents/pharmacology , Child , Child, Preschool , Drug Resistance, Microbial , Erythromycin/pharmacology , Erythromycin/therapeutic use , Humans , Italy , Microbial Sensitivity Tests , Penicillins/pharmacology , Penicillins/therapeutic use , Pharyngitis/microbiology , Streptococcal Infections/microbiology , Streptococcus pyogenes/isolation & purification
15.
Microb Drug Resist ; 6(3): 189-98, 2000.
Article in English | MEDLINE | ID: mdl-11144419

ABSTRACT

Pulsed-field gel electrophoresis (PFGE) has become the gold standard of molecular methods in epidemiological investigations. In spite of its high resolving power, use of the method has been hampered by inadequate laboratory-to-laboratory reproducibility. In the project described here we have addressed this problem by organizing a multilaboratory effort in which the same bacterial strains (subtype variants of the Iberian and Brazilian methicillin-resistant Staphylococcus aureus--MRSA--clones) were analyzed by twenty investigators in thirteen different laboratories according to an indentical protocol, which is reproduced here in detail. PFGE patterns obtained were analyzed at a central laboratory in order to identify specific technical problems that produced substandard macrorestriction patterns. The results including the specific technical problems and their most likely causes are described in this communication. Also listed are seven major epidemic clones of MRSA which have been characterized by molecular fingerprinting techniques and the prototypes of which have been deposited at the American Type Culture Collection, from where they will be available for interested investigators for the purpose of typing MRSA isolates. It is hoped that this communication will contribute to the improvement of the reproducibility and technical/aesthetic quality of PFGE analysis.


Subject(s)
Bacterial Typing Techniques/methods , Laboratories/standards , Methicillin Resistance , Staphylococcus aureus/classification , Staphylococcus aureus/genetics , Electrophoresis, Gel, Pulsed-Field/methods , Electrophoresis, Gel, Pulsed-Field/standards , Humans , Microbiology , Reference Standards , Reproducibility of Results , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Staphylococcus aureus/drug effects
16.
Eur J Clin Microbiol Infect Dis ; 18(4): 260-4, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10385014

ABSTRACT

To assess the spread of the new M phenotype, various erythromycin-resistant Streptococcus pyogenes strains from three Italian cities (Verona, Monza, Florence) were characterised. Each strain was analysed for the presence of genes ermAM and mefA, for the ability to accumulate radioactive erythromycin in the absence of sodium arsenate, for the protein T serological type, and for the DNA macrorestriction profile identified by means of pulsed-field gel electrophoresis. In a number of strains, the presence of the inducible ermAM gene was demonstrated; all these strains were negative in the efflux-pump detection assay, did not possess the mefA gene, and had similar restriction profiles. The strains with the efflux mechanism and mefA gene belonged to different serotypes. Of these, only one serotype, T4, was isolated in all three cities. The restriction profile analysis with SmaI and SfiI revealed a very close correlation between strains with the same serotype.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins , Drug Resistance, Microbial/genetics , Erythromycin/pharmacology , Membrane Proteins/genetics , Methyltransferases/genetics , Streptococcus pyogenes , Bacterial Typing Techniques , Electrophoresis, Gel, Pulsed-Field , Humans , Italy , Phenotype , Polymerase Chain Reaction , Serotyping , Streptococcal Infections/microbiology , Streptococcus pyogenes/classification , Streptococcus pyogenes/drug effects , Streptococcus pyogenes/genetics
17.
Microb Drug Resist ; 3(4): 371-8, 1997.
Article in English | MEDLINE | ID: mdl-9442490

ABSTRACT

A retrospective analysis of susceptibility data available for Group A streptococcal isolates collected between January 1990 and January 1996 at the Hospital Microbiology Laboratory of Monza (North Italy), showed a sharp rise in the erythromycin resistance rates during the last 3 years. Streptococcus pyogenes resistant to erythromycin accounted for approximately 1% of strains isolated between 1990 and 1992; the percentage then rose from 5% in 1993 to almost 39% in 1995. In January 1996, the resistance rates peaked to 81%. A prospective controlled study performed between March and May of 1996 to determine the percentage of erythromycin-resistant Group A streptococci isolated in Monza from untreated children with acute pharyngo-tonsillitis, gave further confirmation of a high rate of erythromycin resistance (47%) in this area. Molecular characterization by T-serotyping and pulse-field gel electrophoresis analysis of 25 erythromycin-resistant Group A streptococcal isolates, showed a relatively high degree of heterogeneity among these strains, demonstrating that the increased resistance is not caused by the spread of a single clone.


Subject(s)
Anti-Bacterial Agents/pharmacology , Erythromycin/pharmacology , Pharyngitis/epidemiology , Pharyngitis/microbiology , Streptococcal Infections/epidemiology , Streptococcal Infections/microbiology , Streptococcus pyogenes/drug effects , Tonsillitis/epidemiology , Tonsillitis/microbiology , Acute Disease , Anti-Bacterial Agents/therapeutic use , Child , Child, Preschool , Drug Resistance, Microbial , Electrophoresis, Polyacrylamide Gel , Erythromycin/therapeutic use , Female , Genes, Bacterial/genetics , Humans , Italy/epidemiology , Male , Microbial Sensitivity Tests , Retrospective Studies , Streptococcus pyogenes/genetics
18.
Microb Drug Resist ; 3(4): 379-84, 1997.
Article in English | MEDLINE | ID: mdl-9442491

ABSTRACT

Resistance to macrolides has increasingly been reported for Group A streptococci. In this study, the in vitro antibiotic susceptibility pattern of 305 clinical isolates of S. pyogenes was determined. Strains were isolated during 1996 from pharyngeal swabs of children with uncomplicated pharyngitis living in 2 Italian cities: Milano and Catania, situated in the North and South of Italy, respectively. All isolates were found to be fully susceptible to penicillin and other beta-lactam agents tested. Susceptibility to macrolides differed markedly between the two centers with relatively high resistance rates to erythromycin being observed in Milano (30%) as compared to Catania (3%). Resistance to erythromycin was always crossed with that of the other 14- and 15-membered macrolides tested. However, resistance to josamycin and clindamycin was generally found in approximately 25% of the erythromycin-resistant (ER) strains. The erythromycin-resistant isolates from Milano and Catania (58 strains) were further subdivided into the three previously described resistance phenotypes: constitutive, inducible, and novel resistance phenotypes. The novel resistance phenotype accounted for 58% of all resistant strains, while 17% and 26% were found to be of the inducible and constitutive resistance phenotypes. Strains of the novel resistance phenotype were characterized by lower MIC values (MIC90 = 16 mg/L) to 14 and 15 carbon atom macrolides as compared to the other two phenotypes (MIC90 > 128 mg/L), and retained susceptibility to clindamycin and to josamycin, a 16 carbon atom macrolide. Resistance to tetracyclines was found in 25% to 36% of the ER isolates as compared to 2% to 10% of the susceptible strains. In particular, resistance to this agent was more commonly associated to isolates belonging to the novel and constitutive resistance phenotypes. MIC values for chloramphenicol in all isolates were within the susceptible or intermediate range; decreased susceptibility to this agent did not appear to be associated with erythromycin resistance.


Subject(s)
Anti-Bacterial Agents/pharmacology , Streptococcus pyogenes/drug effects , Drug Resistance, Microbial , Italy , Macrolides , Microbial Sensitivity Tests , Pharyngitis/microbiology , Phenotype , Streptococcal Infections/microbiology
19.
J Neuroimmunol ; 70(1): 87-90, 1996 Oct.
Article in English | MEDLINE | ID: mdl-8862139

ABSTRACT

The serum levels of the heterodimeric cytokine IL-12 were measured by solid-phase ELISA in a group of healthy subjects, multiple sclerosis (MS) patients with secondary chronic progressive course of the disease and patients suffering from other neurological diseases (OND). Serum levels of IL-12 higher than 5 pg/ml (limit of sensitivity of the assay) were only found in 2/30 (6.7%) of the healthy subjects and none of the 8 subjects with OND. In contrast, IL-12 was found in the majority of CPMS patients' sera (10/15, 66.7%) with values ranging between 5.5 and 18.6 pg/ml. These results are suggestive for an up-regulated production of IL-12 in CPMS.


Subject(s)
Interleukin-12/blood , Multiple Sclerosis/blood , Adult , Chronic Disease , Disease Progression , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged , Nervous System Diseases/blood , Single-Blind Method
20.
Chemotherapy ; 41(4): 229-33, 1995.
Article in English | MEDLINE | ID: mdl-7555201

ABSTRACT

Ceftibuten is a broad-spectrum oral cephalosporin exhibiting antimicrobial activity against a wide range of gram-negative and some gram-positive pathogens. Pharmacokinetic studies have shown that the molecule has an oral bioavailability higher than 90% of the administered dose (reaching peak serum concentrations of 5-19 mg/l after a single dose of 200 and 400 mg). Moreover, ceftibuten has been shown to be useful in the treatment of acute lower respiratory tract infections. This study was performed to determine the distribution of ceftibuten in bronchial secretions from patients affected by the exacerbation of chronic bronchitis. Patients were treated with a single 400-mg oral dose of ceftibuten. Blood and bronchial-secretion samples were obtained just before, and at 0.5, 1, 2, 4, 8, 12, 16 and 24 h after dosing. Cells were separated from bronchial secretions by centrifugation. Ceftibuten in duplicate samples of both serum and bronchial secretion was quantified by HPLC. Ceftibuten reached peak levels 2 and 4 h after oral administration in serum and in bronchial secretions, respectively (18.12 +/- 2.13 and 9.19 +/- 3.1 mg/l, respectively). Falling curves after the peaks showed a monoexponential decay. The absorption was very rapid both in serum and bronchial secretions, but elimination was slower in bronchial secretions than in serum.


Subject(s)
Bronchi/metabolism , Bronchitis/metabolism , Cephalosporins/pharmacokinetics , Administration, Oral , Aged , Biological Availability , Bronchitis/drug therapy , Ceftibuten , Cephalosporins/blood , Cephalosporins/therapeutic use , Female , Humans , Male , Middle Aged , Time Factors
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