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Valutazione del sistema Mycobacteria Growth Indicator Tube-MIGIT per la determinazione dell’antibioticosensibilità di Mycobacterium tuberculosis
No full textDiagnosi rapida di tubercolosi mediante reazione polimerasica a catena (PCR) eseguita direttamente su materiale proveniente dall’apparato respiratorio
No full textEpidemiological observatory: spreading of ESBL and carbapenemase positive strains in the period between January 2007 - June 2012, at the Hospital, University Campus, Hospital “Luigi Sacco” in Milan
No full textInfections caused by ESBL-producing Enterobacteriaceae and carbapenemases producing bacteria are a growing phenomenon which is one of the leading causes of death among elderly or immunosuppressed patients and is also associated with a higher cost of hospitalization. As worldwide, also in Italy a steady and alarming increase of these microorganisms is reported. With the present paper we present a brief review of the prevalence of ESBL-producing and carbapenemase strains isolated at the Hospital - University Campus - Hospital “Luigi Sacco” in Milan between January 2007 and June 2012. Samples ESBLs positive (Vitek2: bioMérieux, France) were subjected to phenotype confirmation by E-test method (bioMérieux, France). In addition 34 K. pneumoniae carbapenemases producing strains collected between 2011 and 2012, were firstly confirmed with an Hodge test and then tested with a NASBA EasyQ KPCv1.0 test (bioMérieux, France) able to detect the bla KPC gene. The data collected showed a high prevalence of ESBLs and carbapenemases producing strains. 1828 out of 15585 were positive for ESBL with the following distribution: 15.6% E. coli, 13.0% K. pneumoniae, 3.6% Enterobacter spp, 7.7% P. mirabilis and 6% P. aeruginosa. Out of 1828, 193 samples (10.5%) were confirmed as positive and respectively 89.4% were E. Coli, 80% were K. pneumoniae and 89.5% were P. mirabilis. The 3.6% of strains were positive for carbapenemase: 45.3% were A. baumannii and 41.8% were P. aeruginosa. K. pneumoniae strains carbapenemase positive were confirmed in 100% of cases by the Hodge test and in 97% of cases by molecular investigation
Evaluation of synergy between glycopeptides, levolfloxacin and beta-lactams against methicillin-resistant Staphylococcus aureus
No full textAttività antimicrobica di ibuprofene isobutanolammonio nei confronti di germi isolati da campioni vaginali
No full textMonitoraggio di ceppi di Acinetobacter baumannii multi-resistenti circolanti in un ospedale della zona nord-ovest di Milano
No full textIntroduzione: A. baumannii è un importante patogeno nosocomiale emergente la cui multi-resistenza agli antibiotici e
la capacità di sopravvivenza nell’ambiente, rendono problematico il trattamento delle infezioni. Epidemie a carico di
cloni di tale patogeno, principalmente I-III, sono state descritte in tutto il mondo e anche in Italia.
Scopo del presente lavoro è stato quello di monitorare la diffusione dei ceppi di A. baumannii multi-resistenti (MDR)
circolanti nell’A.O.-Polo Universitario “L.Sacco” di Milano.
Metodi: Diciannove ceppi di A. baumanni MDR sono stati collezionati da Marzo 2010 a Febbraio 2011 nell’ambito
dello studio T.E.S.T. 2010 (Tigecycline Evaluation Surveillance Trial, IHMA). Il 31.6% (6/19) dei ceppi proveniva da
pazienti ricoverati in area critica e il 57.9% (11/19) sono stati isolati dal tratto respiratorio e da tampone lesione/piaga. Il
68.4% (13/19) era riconducibile ad infezioni nosocomiali. I saggi di sensibilità sono stati eseguiti mediante
microdiluizione in brodo e Vitek2 (bioMérieux, Francia), e la classificazione MDR è stata fatta in base ai breakpoint
EUCAST e CLSI. Tali ceppi sono stati sottoposti a tipizzazione molecolare tramite la tecnica RAPD con primer M13.
Risultati: I ceppi in esame sono risultati tutti resistenti ai carbapenemi mentre gli antibiotici più attivi sono risultati
colistina (19/19 sensibili) e tigeciclina (15/19). Dalla tipizzazione molecolare è emerso un solo profilo RAPD
fortemente correlato (percentuale di similitudine > dell’85%) con il clone europeo II (E2).
Conclusioni: L’emergente resistenza ai carbapenemi è associata alla diffusione di ceppi multi-resistenti appartenetti al
clone II. Dalla presente sorveglianza tutti i ceppi di Acinetobacter presi in esame sembrerebbero riconducibili al clone
europeo II, estremamente adattabile e in grado di acquisire rapidamente caratteri di resistenza agli antibiotici. L’impiego
della tigeciclina, che insieme alla colistina è risultato l’antibiotico più attivo in vitro nelle infezioni da A. baumannii,
resta oggetto di dibattito poiché i dati clinici sul suo utilizzo sono scarsi
In vitro selection of resistance in Pseudomonas aeruginosa and Acinetobacter spp. by levofloxacin and ciprofloxacin alone and in combination with beta-lactams and amikacin
No full textObjectives: The aim of this study was to evaluate the ability of levofloxacin and ciprofloxacin alone and in combination with either ceftazidime, cefepime, imipenem, piperacillin–tazobactam or amikacin to select for antibiotic-resistant mutants of Pseudomonas aeruginosa and Acinetobacter spp.
Methods: Clinical strains of P. aeruginosa (n = 5) and Acinetobacter spp. (n = 5) susceptible to all the drugs used in the study were assayed. Development of resistance was determined by multi-step and single-step methodologies. For multi-step studies, MICs were determined after five serial passages on antibiotic-gradient plates containing each antibiotic alone or in combination with levofloxacin or ciprofloxacin. Acquisition of resistance was defined as an increase of ≥4-fold from the starting MIC. In single-step studies, the frequency of spontaneous mutations was calculated after a passage on plates containing antibiotics alone and in combinations at concentrations equal to the highest NCCLS breakpoints.
Results: Serial passages on medium containing single antibiotics resulted in increased MICs for each antibiotic; MIC increases were limited by antibiotics in combination. A decrease in the number of strains with MICs above the NCCLS breakpoints occurred when fluoroquinolones were combined with a second antibiotic for both P. aeruginosa and Acinetobacter spp. isolates. Frequencies of mutation were higher for antibiotics alone than for combinations.
Conclusions: Use of combinations of fluoroquinolones with β-lactams and amikacin reduces the risk for in vitro selection of resistant P. aeruginosa and Acinetobacter spp
In vitro antimicrobial activity of propolis dry extract
No full textIn this study the antibacterial and antifungal properties of propolis, a natural product of bees, have been investigated against different pathogens. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined according to NCCLS standards on 320 strains including Staphylococcus aureus, Group A beta-hemolytic streptococci, Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans, Time-kill curves were assessed for susceptible microorganisms, testing 0, 0.5, 1, 2, 4 x MIC for propolis, by counting viable bacteria after 0, 3, 6, 24 hours and viable yeasts after 0, 3, 6, 24 and 48 hours. Propolis showed good antimicrobial activity against most of the isolates, particularly S. pneumoniae, H. influenzae and M. catarrhalis, but not against Enterobacteriaceae. Time-kill curves demonstrated bacteriostatic rather than bactericidal activity of propolis, the Latter being evident only at high concentrations
Comparative in vitro activity of thiamphenicol-glycinate and thiamphenicol-glycinate-acetylcysteinate and other antimicrobials against respiratory pathogens
No full textThiamphenicol-glycinate-acetylcysteinate (TGA; CAS 20192-91-0) is widely used for the treatment of infections of varied aetiology. The aim of this study was to compare the antibacterial activity of thiamphenicol-glycinate (TG; CAS 15318-45-3), TGA, amoxicillin (CAS 61336-70-7) plus clavulanic acid (CAS 58001-44-8), azithromycin (CAS 83905-01-5) and ceftriaxone (CAS 104376-79-6). Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined against Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae according to the National Committee for Clinical Laboratory Standards (NCCLS) methods. The effects of changes in assay conditions were also examined. The activity of TG and TGA was similar to that of amoxicillin plus clavulanic acid, with the exception of methicillin resistant S. aureus. Azithromycin and ceftriaxone were characterised by a limited activity against gram-positive cocci and methicillin resistant and cefinase-positive S. aureus, respectively. TG and TGA are characterized by a wide spectrum of activity, comparable to that of recent commercialized antibiotics for treatment of respiratory tract infections
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