Grazia Morandotti

In Vitro Activity of Azithromycin against Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis in Comparison with Erythromycin, Roxithromycin and Minocycline

The in vitro activity of azithromycin against 40 strains of Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis was investigated in comparison with erythromycin, roxithromycin and minocycline. All C. trachomatis strains were inhibited by azithromycin at a concentration < or = 0.5 microgram/ml. The initial minimum inhibitory concentration (MIC) of the drug for U. urealyticum was 4 microgram/ml, whereas some resistance against the drug was shown by M. hominis. Erythromycin and roxithromycin presented almost comparable activities, whereas minocycline was slightly more active than macrolides against C. trachomatis (MIC < or = 0.25) and more active against M. hominis (initial MIC < or = 1 micrograms/ml). Only 97% of U. urealyticum strains were susceptible to 8 micrograms/ml of minocycline.

A new class of cis-monobactam derivatives bearing a sulfamoyloxymethyl or an N-alkylsulfamoyloxymethyl group at position 4: synthesis and antibacterial activity.

A new series of monobactam derivatives, bearing unsubstituted or N-monosubstituted sulfamoyloxymethyl groups in position 4 was synthesized either in racemic or in optically active form. Their in vitro antibacterial activity was tested in comparison with carumonam 1a and its methoxyimino derivative 1b.

Synthesis and antibacterial activity of men 10700, a new penem antibiotic

The new penem antibiotic Men 10700 (3), bearing an amino acid derived amide as C-2 side chain, was synthesized. Men 10700 exhibited high potency and a broad spectrum of activity against Gram positive and Gram negative microorganisms.

Comparison of Mycoplasma IES, Mycofast Revolution and Mycoplasma IST2 to detect genital mycoplasmas in clinical samples

INTRODUCTION Culture is regarded as the gold standard for the detection of genital mycoplasma in clinical samples. Commercially available diagnostic kits, based on liquid broth cultures, provide interesting alternatives to conventional culture. We assessed the laboratory performances of Mycoplasma IES (IES), the Mycofast Revolution (REV) and Mycoplasma IST 2 (IST2) compared to A7 agar plates for the detection of Ureaplasma urealyticum and Mycoplasma hominis in clinical samples. METHODOLOGY From April to July 2013, endocervical or vaginal samples were collected from sexually active women with abnormal vaginal discharge. Each specimen was tested in parallel using the three commercial kits and the A7 agar plates. RESULTS A total of 303 samples were included in this study, 35.6% (108/303) of which were positive on A7 plates. Sensitivities for the detection of U. urealyticum of IES, REV and IST2 were 100%, 96.2% and 95.3%, respectively while those for M. hominis were of 92.8%, 92.8% and 85.7%, respectively. Specificity was 100% for the 3 methods. Concerning antimicrobial susceptibility testing, full agreement between IES and REV was documented. CONCLUSIONS The Mycoplasma IES kit was found to be equivalent or superior compared to other commercial culture-based assays for a rapid and accurate identification of U. urealyticum and M. hominis and detection of resistance. It might be considered a cost-effective tool for detection of these organisms, particularly attractive in developing countries.

Forecasting ESKAPE infections through a time-varying auto-adaptive algorithm using laboratory-based surveillance data

BackgroundMathematical or statistical tools are capable to provide a valid help to improve surveillance systems for healthcare and non-healthcare-associated bacterial infections. The aim of this work is to evaluate the time-varying auto-adaptive (TVA) algorithm-based use of clinical microbiology laboratory database to forecast medically important drug-resistant bacterial infections.MethodsUsing TVA algorithm, six distinct time series were modelled, each one representing the number of episodes per single ‘ESKAPE’ (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) infecting pathogen, that had occurred monthly between 2002 and 2011 calendar years at the Università Cattolica del Sacro Cuore general hospital.ResultsMonthly moving averaged numbers of observed and forecasted ESKAPE infectious episodes were found to show a complete overlapping of their respective smoothed time series curves. Overall good forecast accuracy was observed, with percentages ranging from 82.14% for E. faecium infections to 90.36% for S. aureus infections.ConclusionsOur approach may regularly provide physicians with forecasted bacterial infection rates to alert them about the spread of antibiotic-resistant bacterial species, especially when clinical microbiological results of patients’ specimens are delayed.

In Vitro Susceptibility to Seven Antifungal Agents of Candida lusitaniae Isolates from an Italian University Hospital

Although Candida lusitaniae remains a rarely encountered Candida species 1, this yeast is able to cause serious and lifethreatening infections 2, and has become the seventh species responsible for invasive candidiasis worldwide 3,4. In addition to its frequency, C. lusitaniae is uniquely distinguished from other Candida species for its tendency to exhibit amphotericin B resistance that can develop rapidly during therapy 5, through a ‘switching phenotype’ 6. This phenotype was shown to seriously affect susceptibility not only to amphotericin B but also to fluconazole and itraconazole 7. Thus, emergence of resistant C. lusitaniae isolates to azole antifungal agents has been reported 7-9, as well as decreased susceptibility to flucytosine 1,8,10,11. In contrast, there was no evidence of resistance to voriconazole and posaconazole among C. lusitaniae isolated from blood cultures 9. To provide further data about the antifungal susceptibility pattern of C. lusitaniae, we report here the in vitro activities of four ‘older’ systemic antifungal agents (amphotericin B, flucytosine, fluconazole and itraconazole) and of the newly licensed caspofungin, voriconazole and posaconazole against a panel of C. lusitaniae isolates of diverse clinical origin, all of which were derived from a single Institution. The 132 isolates of C. lusitaniae were recovered from vagina (41 isolates), lower respiratory tract (37) urine (21), stool (17), pharynx (8), blood (4), pus (3) and skin (1) of 132 patients hospitalized in our institution, between January 2003 and December 2008. Isolates were identified to the species level by standard morphologic methods and by VITEK 2 and RapID Yeast Plus biochemical systems. At the time of their isolation, standard primary cultures had been carefully examined for the presence of colony variants, but no colony morphology switching had been detected for any isolate. The minimum inhibitory concentrations (MICs) of amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole, posaconazole and caspofungin were determined using the Clinical and Laboratory Standards Institute (CLSI) microdilution broth (reference method) 12. The final concentrations of the antifungal agents were 0.03 to 16 mg/L for amphotericin B, itraconazole, posaconazole and voriconazole, 0.125 to 64 mg/L for flucytosine and fluconazole, and 0.015 to 8 for caspofungin. Testing for amphotericin B was also performed by Etest (AB BIODISK, Solna, Sweden) as recommended. Microdilution trays and Etest agar plates were incubated at 35°C for 24 to 48 h. MICs were defined as the lowest drug concentrations that caused either approximately 50% (azoles, flucytosine and caspofungin) or 100% (amphotericin B) growth inhibition compared with that of the drug-free growth control 12, whereas in the Etest method they were read as the lowest concentration at which the border of the elliptical inhibition zone intersected the scale on the test strip. For comparison purposes, Etest 48 h MICs were rounded to the next higher concentration of the CLSI reference method and MIC values were considered in agreement when they were no more than 2 log2 dilutions apart. To classify the isolates, established CLSI interpretive MIC breakpoints for flucytosine, fluconazole, voriconazole and itraconazole were used: isolates were defined as susceptible (≤4, ≤8, ≤1 and ≤0.12 mg/L, respectively), susceptible dose-dependent/intermediate (8 to 16, 16 to 32, 2 and 0.25 to 0.5 mg/L, respectively) or resistant (≥32, ≥64, ≥4 and ≥1 mg/L, respectively) 12. Also, in agreement with current guidelines 12, isolates were defined as susceptible to amphotericin B or posaconazole at an MIC of ≤1 mg/L, and to caspofungin at an MIC of ≤2 mg/L. The CLSI quality control strains Candida parapsilosis ATCC 22019 and Candida krusei ATCC 6258 were tested and MICs were within the described limits 12. As shown in table 1, amphotericin B was among the most active antifungal agents tested, followed by posaconazole, voriconazole and itraconazole. Conversely, broad MIC ranges were seen for caspofungin, fluconazole and flucytosine; nonetheless, 92% to 98% of our isolates were susceptible to flucytosine (MIC ≤4 mg/L) and fluconazole (MIC ≤8 mg/L), with only three isolates found to be resistant to each drug (MICs 64 mg/L) respectively, whereas 99% were susceptible at ≤2 mg/L with only one isolate categorized as nonsusceptible (MIC >2 mg/L) to caspofungin 12. One of three fluconazole-resistant isolates had also dose-dependent susceptibility to itraconazole (MIC 0.5 mg/L) 12. The proportion of C. lusitaniae isolates resistant to fluconazole and flucytosine in this study was essentially similar to that reported elsewhere 1,8,11. While the excellent activity of the older fluconazole, flucytosine and also itraconazole against C. lusitaniae was thus confirmed, we also found this Candida species to be susceptible to the newer antifungal agents, such as caspofungin, voriconazole and posaconazole. As noted previously 9,11,13,14, the new triazoles (voriconazole and posaconazole) were more active (100% of isolates susceptible at ≤1 mg/L) than fluconazole. Caspofungin displayed very good activity against our isolates, with an MIC of 1 mg/L or lower in 99% of isolates, except for a single isolate not inhibited at an MIC of 8 mg/L. This finding appeared not exactly in line with two recent large surveillance studies of bloodstream Candida isolates (including a few number of C. lusitaniae) showing that all Candida species, with the exception of C. parapsilosis, were susceptible to caspofungin 13,14. In contrast, one of 13 C. lusitaniae isolates studied by St-Germain et al. 13 exhibited decreased susceptibility to amphotericin B (MIC 2 mg/L), but this observation concurred with those of previous studies 1,8,10,11 in indicating that in vitro resistance to this drug remains uncommon, not only in C. lusitaniae but also in the most frequently isolated Candida species (e.g. Candida albicans or Candida glabrata). None of the isolates in the present study had an amphotericin B exceeding 1 mg/L, but as stated in the CLSI M27-A3 document 12, the M27 methodology we used does not consistently allow detection of Candida isolates with MIC values greater than 1 mg/L, i.e. isolates likely resistant to amphotericin B. According to the consensus that agar-based methods such as Etest may be the most sensitive and reliable means of detecting resistance to amphotericin B among Candida species 15, we also determined amphotericin B susceptibility by Etest. By using this method, specific differences had previously been noted in the susceptibilities of various species of Candida to amphotericin B 1, although 50% and 90% of the C. lusitaniae isolates studied had MICs to this agent of 0.25 mg/L and 1 mg/L, respectively, as compared to the C. glabrata (MIC50 Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Largo F. Vito 1, 00168 Rome, Italy