[Comparative activity of doripenem, meropenem, and imipenem in recent clinical isolates obtained during the COMPACT-Spain epidemiological surveillance study]

INTRODUCTION

Doripenem is a new carbapenem with broad spectrum antibacterial activity indicated for the treatment of nosocomial pneumonia and complicated urinary and intraabdominal infections.

METHODS

Isolates of Pseudomonas aeruginosa, Acinetobacter and Enterobacteriaceae from patients with nosocomial pneumonia, bacteremia and complicated intraabdominal infections attended in 16 Spanish hospitals were included (October 2008-May 2009). Susceptibility to imipenem, meropenem and doripenem was studied with the Etest method, and the results were interpreted according to the EUCAST criteria.

RESULTS

Considering all the isolates, doripenem (MIC(50) 0.12 mg/L) was 2- to 8-fold more active than meropenem (0.25 mg/L) and imipenem (1 mg/L). In relation to Enterobacteriaceae, the MIC(50) and MIC(90) values of doripenem and meropenem were similar (0.03 and 0.12 mg/L, respectively) and clearly superior to those of imipenem (0.25 and 1 mg/L). In the case of P. aeruginosa, MIC(50) and MIC(90) were more favorable to doripenem (0.25 and 16 mg/L) than to meropenem (0.5 and ≥64 mg/L) or imipenem (2 and ≥64 mg/L). In this species, the percentage of strains with lower MIC values for doripenem among those exhibiting intermediate susceptibility and resistance to meropenem was 63.0% (29/46) and 61.7% (63/102), respectively, versus only 4.3% (2/46) and 1.9% (2/102) with higher MIC values for doripenem.

CONCLUSIONS

The results obtained in this study are similar to those reported in other countries, and reinforce the superior in vitro activity of doripenem versus the other carbapenems and its position in the treatment guidelines regarding the nosocomial infections for which it is indicated.

[Recommendations in the empiric anti-infective agents of intra-abdominal infection]

A significant number of patients with abdominal infection develop advanced stages of infection and mortality is still above 20%. Failure is multifactorial and is associated with an increase of bacterial resistance, inappropriate empirical treatment, a higher comorbidity of patients and poor source control of infection. These guidelines discuss each of these problems and propose measures to avoid the failure based on the best current scientific evidence.

Onychomadesis outbreak in Valencia, Spain, June 2008

Onychomadesis describes complete nail shedding from the proximal portion. It is consecutive to a nail matrix arrest and can affect both fingernails and toenails. It is a rare disorder in children. Except for serious generalised diseases or inherited forms, most cases are considered to be idiopathic. Nail matrix arrest has been associated with a variety of drug exposures and systemic illnesses, including infections, and may result in a variety of changes, including transverse ridging (Beau's lines) and nail shedding (onychomadesis).

[Recommendations of antifungal treatment in patients with low grade immunosuppression]

Because of the relevance that the systemic mycoses has acquired in non-highly immunocompromised patients, the treatment difficulties they have due to the increase of the non-albicans Candida species and the need to have a better and more rational use of the new antifungal agents (voriconazole, posaconazole, caspofungin, anidulafungin and micafungin), an experts' panel on infectious diseases in representation of the Spanish Society of Chemotherapy, Spanish Society of Internal Medicine, and Spanish Society of Pneumology and Thoracic Surgery has met in order to make a few recommendations based on the scientific evidence in an effort to improve their efficiency.

[Anidulafungin]

Anidulafungin is a new echinocandin antifungal agent recently approved in Spain by the Spanish Drug Agency. As other echinocandins, it inhibits a selective target, 1,3- beta-D-glucan synthesis, a major structural component of the fungal cell wall which is not present in mammalian cells, this avoiding toxicity problems. It has fungicidal activity against many Candida spp., including fluconazole-resistant, and fungistatic activity against other yeast and moulds such as Aspergillus spp. Clinical trials have shown non-inferiority of anidulafungin to fluconazole for invasive, including candidemia, and non-invasive Candida infections. It is well-tolerated, and no drug-related serious adverse events have been reported. Anidulafungin, which has a very long half life, is slowly degraded by human peptidases and proteases and has a low drug-drug interaction profile based on its lack of interaction with the cytochrome P450 system. Thus, dosing adjustments of anidulafungin based on age, gender, body weight, disease status, concomitant therapy or renal or hepatic insufficiency is not necessary. As it does not interact with amphotericin B and voriconazole, cyclosporine, tacrolimus and other drugs, it can be used in combination with other antifungal agents and co-administered with immunosuppressant drugs. It is generally well-tolerated in clinical trials. Its most frequent adverse events are nausea, vomiting, moderate diarrhea, transient elevation of hepatic enzymes and headache. Some of the patients have mild, passing reactions such as facial blushing, nausea and dyspnea related with rapid intravenous perfusion. Its antifungal activity, clinical efficacy, safety profile, and pharmacokinetic characteristics make it a suitable alternative antifungal compound for therapy of mucosal candidiasis, candidemia and invasive candidiasis, above all in patients with some degree of renal and hepatic insufficiency.

[In vitro activity of ertapenem against clinical bacterial isolates in 69 Spanish medical centers (E-test study)]

This study was conducted to assess the in vitro activity of ertapenem against clinical bacterial isolates from patients with community-acquired intra-abdominal and lower tract respiratory infections in Spain in 2003. As the study was conducted before the marketing of ertapenem, it was also useful to define a baseline susceptibility pattern for ertapenem in each of the participating hospitals for later surveillance studies. Each partipating site identified a variable number of aerobic and facultative bacteria isolated from patients with community-acquired intra-abdominal infection or pneumonia using standard procedures. E-test strips were used for determining the minimum inhibitory concentration (MIC) of ertapenem, while for other antimicrobials either quantitative dilution techniques or qualitative diffusion procedures were used according to each microbiology laboratory's routine practice. MIC breakpoints for categorization of susceptibility provided by the CLSI were used for interpreting MIC values. A total of 2,901 recent clinical isolates from patients with community-acquired intra-abdominal infection or pneumonia hospitalized in 69 Spanish medical centers were tested. These isolates included 2,039 Gram-negative bacteria (1,646 Enterobacteriaceae, 216 Haemophilus, 123 non-fermenting Gram-negative bacteria [NFGNB] and 54 others) and 862 Gram-positive bacteria (556 pneumococci, 159 staphylococci, 96 streptococci other than S. pneumoniae, 44 enterococci and 7 others). Ertapenem was very active in vitro against Enterobacteriaceae (99.8% susceptible), Haemophilus (96.3% susceptible), pneumococci (99.6% susceptible, of which 31% were penicillin non-susceptible strains), streptococci other than S. pneumoniae (99.0% susceptible) and methicillin-susceptible staphylococci (94.8% susceptible). For other Gram-positive and Gram-negative pathogens for which ertapenem susceptible breakpoints have not been defined, MIC(90) values were 0.38 and 0.064 mg/l, respectively. As expected, ertapenem had minimal activity in vitro against NFGNB, enterococci and methicillin-resistant staphylococci (MIC(90) of >32 mg/l for all three). Ertapenem was highly active in vitro against most bacteria isolated from patients with community-acquired intra-abdominal and lower respiratory tract infections.

[The fungicidal activity and paradoxical effect of caspofungin against yeast. Influence of culture medium and incubation time]

The effect of culture medium and incubation time on the fungicidal activity of caspofungin and on the frequency of paradoxical effect has been studied in 144 blood culture isolates (42, Candida tropicalis, 32 Candida glabrata, 21 Candida krusei, 20 Candida parapsilosis, 11 Candida guilliermondii, 4 Candida famata, 3 Candida lusitaniae, 3 Blastoschizomyces capitatus, 2 Saccharomyces cerevisiae, 2 Yarrowia lipolytica, 1 Candida inconspicua, 1 Candida lambica, 1 Candida sake y 1 Pichia ohmeri). The media assayed were standard RPMI 1640, Antibiotic Medium #3 (AM#3) and AM#3 with 2% of dextrose (AM#3-G). MIC(2) (>or= 50% growth inhibition) and MIC(0) (100% inhibition) at 24 and 48h and the minimum fungicidal concentration (MFC) were determined. The greatest activity of caspofungin was obtained in AM#3 medium followed by AM#3-G and RPMI. Geometric means (GM) MIC(2) at 24/48 h incubation were 0.06/0.12, 0.1/0.2 and 0.65/0.89 mg/l, respectively. GMMIC(0) was 0.1/0.17 (AM#3), 0.16/0.25 (AM#3-G) and 1.06/1.7 mg/l (RPMI). Caspofungin showed fungicidal activity in the three media (GM-MFC, 0.28, 0.38 and 3 mg/l in AM#3, AM#3-G and RPMI, respectively). The percentage of caspofungin tolerant isolates (MFC >or=8 x MIC(0)) was 8.09% (AM#3), 8.3% (AM#3-G) and 13.9% (RPMI). RPMI was the medium less affected by the incubation time and AM#3 the most affected (93.7 and 78.2% of isolates the MIC(2) increased <or=2 Log from 24 to 48 h incubation, respectively). The frequency of paradoxical effect was species-, isolate- and medium- dependent. It is observed at <or=8 mg/l (RPMI), >or=2 mg/l (AM#3) and >or=4 mg/l (AM#3-G). The highest frequency was obtained in RPMI medium and C. tropicalis species and the lowest frequency for C. krusei y C. glabrata.

[Epidemiology of genotypic resistance of HIV-1 in Valencia. A 4-year study]

HIV resistance to antiretroviral drugs was studied in 348 samples taken from patients at the Molecular Biology Unit of the Microbiology Department of the Hospital La Fe, from January 2003 to July 2007. Once the viral load in plasma was determined, resistance was detected using complete gene sequencing for protease up to position 3464 of the HIV-1 reverse transcriptase gene. The results were analyzed using the Omiga 1.2 (Oxford Molecular Group) and HIV db Genotypic Resistance Interpretation Algorithm Version 4.3.0 (Stanford University) programs. The drugs least affected by the presence of mutations leading to resistance were the protease inhibitors darunavir, tripanavir and lopinavir (sensitivity >80%), the nucleoside reverse transcriptase inhibitors tenofovir and lamivudine (sensitivity >90%) and the non-nucleoside reverse transcriptase inhibitor TMC125 (sensitivity >80%).

Quinolone resistance in female outpatient urinary tract isolates of Escherichia coli: age-related differences

During a 1-year period, from November 2003 to October 2004, urinary Escherichia coli isolates were collected from 20 clinical microbiology laboratories across Spain. The main objective was to assess the resistance of E. coli to the antimicrobials most commonly prescribed for community-acquired urinary tract infections depending on the patient's age. A total of 2,230 valid E. coli strains from female outpatients were isolated and sent to a single central reference laboratory for confirmation and susceptibility testing using an agar dilution method. A two-sided chi-squared test was used to assess the differences in resistance between age groups (< or =65 and >65 years). E. coli resistance was found to be more common to ampicillin (52.1%), cotrimoxazole (26%) and quinolones (18%), whereas resistance to amoxicillin-clavulanic acid, cefuroxime axetil and fosfomycin were below 3%. In women older than 65 years, resistance to ciprofloxacin reached up to 29% compared with 13% of those in the under 65 age group (p <0.001). For cotrimozaxole, rates were 32% vs. 23% (p <0.001) and for ampicillin 56% vs. 50% (p=0.02), respectively. It was concluded that fosfomycin, amoxicillin-clavulanic acid and cefuroxime axetil are the most suitable antimicrobials for empirical treatment in Spain given the high 18% and 26% resistance rates to quinolones and cotrimoxazole, respectively. Being older than 65 years of age was associated with higher resistance rates to ciprofloxacin (29%). These results should be considered when recommending empirical therapy for acute cystitis in women.

Antimicrobial susceptibility of clinical Escherichia coli isolates from uncomplicated cystitis in women over a 1-year period in Spain

High usage of antibiotics in Spain has led to an increase in resistance in urinary Escherichia coli isolates in different geographic regions. The problem of resistance in urinary E. coli in Spain was investigated by gathering a large number of isolates from 20 different sites nationwide over a 1-year period from November 2003 to October 2004 in a large population of women. The objectives of this study were to assess the resistance to the antibiotics most commonly prescribed for community-acquired urinary tract infections (UTIs), according to age and different geographical areas of Spain, and to evaluate the potential association between geographical differences in quinolone consumption and resistance to E. coli. A total of 2,292 valid E. coli strains from female outpatients were isolated and sent to a single central reference laboratory for confirmation and susceptibility testing. Of these, 2,230 isolates were available for the age analysis. A two-sided chi2 test was used to identify differences in resistance between age groups. Antibiotic units per province were purchased from IMS and consumption was expressed in units per 1,000 people per year. Univariate correlation (Pearson coefficient) between resistance to ciprofloxacin and quinolone consumption was calculated using a two-sided p-value. Resistance shown by E. coli was more common to ampicillin (52.1%) and cotrimoxazole (26%), followed by quinolones (18%), whereas resistance to amoxicillin-clavulanic acid, cefuroxime-axetil and fosfomycin was less than 3%. In the subgroup of women aged >65 years, resistance to ciprofloxacin was 29% compared to 13% for the subgroup of women <65 years (p<0.001). For these same subgroups, resistance rates were 32% vs. 23% for cotrimoxazole (p<0.001) and 56% vs. 50% for ampicillin (p=0.02), respectively. Statistically significant correlations were found between consumption of quinolones and E. coli resistance to ciprofloxacin (r=0.5; p=0.025). Resistance of E. coli isolates to quinolones varied significantly according to geographical areas, ranging from a high of 16.5% and 16.6% in the southern and eastern regions of Spain, respectively, to a low of 8% in the north in women aged <65 years. Additionally, the susceptibility to quinolones of E. coli isolates recovered from women aged >65 years was significantly lower across all regions of Spain than that of isolates recovered from younger women. Fosfomycin, amoxicillin/clavulanic acid and cefuroxime-axetil are the most suitable antibiotics for empirical treatment in Spain given the high 18% and 26% resistance rates to quinolones and cotrimoxazole, respectively. Higher resistance rates to ciprofloxacin were associated with being aged 65 years and over. These data need to be considered when recommending empirical therapy for acute cystitis.

In vitro activity of linezolid in combination with doxycycline, fosfomycin, levofloxacin, rifampicin and vancomycin against methicillin-susceptible Staphylococcus aureus

The objective of this paper was to investigate the in vitro effects of linezolid combined with five antistaphylococcal antibiotics--doxycycline, fosfomycin, levofloxacin, rifampicin and vancomycin--upon methicillin-susceptible Staphylococcus aureus (MSSA). Five MSSA isolates from clinical specimens of human infections--hf008, hf095, hf295, hf602 and hf946--were used in this study. The checkerboard method was used to assess synergism between linezolid and the five antibiotics, and time-kill curves were carried out with the most active combinations. Indifference was the most common result achieved by the checkerboard method when linezolid was combined with rifampicin, vancomycin or doxycycline. The combination with levofloxacin yielded antagonism for two of the five isolates. However, four isolates showed synergy for the combination of linezolid plus fosfomycin with a fractional inhibitory concentration index (FICI) > or = 0.5. Neither linezolid nor fosfomycin alone inhibited growth at 1/4x minimum inhibitory concentration (MIC); but the combination of both drugs at 1/4 the respective MIC showed a synergistic bacteriostatic effect, a 2-3 log(10) decrease with respect to the most active antibiotic alone. In summary, the combination of subinhibitory.

[In vitro activity of voriconazole against yeast and algae isolates according to new resistance pattern cut-off points]

Voriconazole is a second-generation triazole derived from fluconazole but with greater potency and spectrum of activity, showing good in vitro activity against Candida, Cryptococcus and Aspergillus species, and other filamentous and dimorphic fungi. It can be administered orally or intravenously. It was initially approved in 2002 by the U.S. Food and Drug Administration as a treatment option for invasive aspergillosis and Fusarium and S. apiospermum infections showing resistance or intolerance to other antifungals; later on, it also received approval in the United States and Europe as a treatment option for esophageal candidiasis; candida infection in non-neutropenic patients; disseminated candidiasis of skin, abdomen, kidney and bladder; and injuries. Recently, the Clinical Laboratory Standard Institute established some provisional break points for voriconazole, classifying isolates with an MIC<or=1 mg/l as susceptible, those with a 2 mg/l MIC as susceptible-dose dependent, and those with an MIC>or=4 mg/l as resistant. In line with these new data, we performed a systematic review of literature on in vitro activity of voriconazole against yeast and algae isolates, and compared it to that of fluconazole and itraconazole. The review included a total of 27,340 yeast isolates, 24,177 of Candida species, 2,726 of Cryptococcus species, 453 of other species, and 104 Prototheca. The yeast isolates resistant to voriconazole is approximately 1%, and 71% of fluconazole-resistant isolates are susceptible to voriconazole.

[Patterns of susceptibility to antibiotics of Enterobacteriaceae causing intra-abdominal infection in Spain: SMART 2003 study outcomes]

SMART (Study for Monitoring Antimicrobial Resistance Trends) is an ongoing global antimicrobial surveillance program focused on clinical isolates from intra-abdominal infections. The objective of this subanalysis was to assess antimicrobial susceptibility patterns among Entero-bacteriaceae recovered at 13 participating Spanish sites during 2003. Antimicrobial susceptibility testing was performed using broth microdilution techniques according to the CLSI (formerly NCCLS) guidelines for MIC testing. The presence of extended-spectrum beta-lactamases (ESBL) was confirmed in isolates with a MIC of ceftriaxone, ceftazidime, or cefepime>or=2 mg/l by comparing cefepime MICs with and with-out clavulanate. A total of 981 Enterobacteriaceae recovered from 840 patients were tested, of which 398 (41%) were community-acquired. Escherichia coli was the most common isolate (571 isolates; 58%), followed by Klebsiella spp. (153; 16% Enterobacter spp. (97; 10%), and Proteus spp. (63; 6%). A total of 191 isolates (19%) from 176 patients produced inducible beta-lactamases. The carbapenems and amikacin were the most consistently active agents against the Enterobacteriaceae (susceptibility>or=99%). Resistance rates for ceftazidime, cipro-floxacin, and levofloxacin exceeded 10%. ESBLs were detected phenotypically in 61 (6%) isolates, being the most common E. coli (61%), Klebsiella spp. (20%), and Enterobacter spp. (8%). Antimicrobial resistance among Enterobacteriaceae isolated from intra-abdominal infections is a problem in Spain. A significant proportion of inducible beta-lactamase and ESBL-producing Enterobacteriaceae causing intra-abdominal infection were acquired in the community. The carbapenems ertapenem, imipenem and meropenem and the aminoglycoside amikacin were highly active in vitro against Enterobacteriaceae isolated from intra-abdominal sites, including ESBL-producing organisms.

[Activity of voriconazole against yeasts isolated from blood culture determined by two methods]

The in vitro activity of voriconazole has been determined by two methods: the reference M27-A2 and the marketed Sensititre YeastOne microdilution colorimetric method. The agreement (+/-2 dilutions) and correlation between methods as well as the percentage of errors has been determined. A total of 144 yeasts (47 Candida albicans, 52 C. parapsilosis, 13 C. tropicalis, 10 C. krusei, 9 C. glabrata, 2 C. guilliermondii, 1 C. colliculosa, 1 C. dubliniensis, 2 Trichosporum asahii, 1 T. mucoide, 1 Trichosporum spp., 1 Kloakera apis, 2 Pichia ohmeri, and 2 Rhodotorula glutinis) isolated from blood culture between October 2002 and May 2005 were assayed. Voriconazole has shown good in vitro activity. The rate of voriconazole-susceptible (MIC < or =1 mg/l) strains was 97% and the MIC90 0.25 mg/l by the two methods. The overall percentage of agreement between methods was 86% (range 44.23-100%) and the Pearson's coefficient of correlation was 0.961. Categorical agreement was strain dependent and ranged from 84.6% for emergent yeasts to 100% for the other species tested except for C. glabrata (66.6%). No major or very major errors were found, the percentage of minor errors being 1.38%. Only one C. tropicalis and one C. glabrata strain were resistant (MIC > or =4 mg/l) to voriconazole (1.38%) by the reference method. The colorimetric method identified the voriconazole-resistant C. tropicalis strain, and classified the C. glabrata as susceptible-dose dependent. The colorimetric method is a potential alternative method for testing the susceptibility of yeast in a clinical laboratory and identifies the susceptible strains (100% agreement) very well. Nevertheless, further studies including more voriconazole-resistant strains are required to determine the ability of the method to identify resistance, which is the goal of susceptibility tests.

[In vitro susceptibility to antibiotics and the most common Streptococcus pneumoniae serotypes: a multicenter study]

The susceptibility and serotypes of 211 strains of Streptococcus pneumoniae collected from 12 Spanish hospitals in December 2003 were studied. Susceptibility tests for eight antibiotics were carried out by E-test, and the serotype classification was carried out using pneumococcus antiserum from the Copenhagen Statens Serum Institute. Overall, the most frequent serotypes were 19 (12.2%); 6 (10.7%); 23 (10.2%); 3 (8.1%); 9 (6.6%); 14 (6.1%); and 29 (5.1%). In blood, the most frequent were 19 (16.6%) and 14 (11.9%), and 8.6% were nontypable. Under NCCLS (M7-A5) criteria, 55.6% of the strains were susceptible to penicillin (MIC < or =0.06 mg/l) and 7.9% showed high resistance (MIC > or =2 mg/l). Susceptibility to other antibiotics was 98% to moxifloxacin; 97.1% to levofloxacin; 94.6% to amoxicillin-clavulanic acid; 71.2% to cefuroxime; 84.4% to ceftriaxone; and 63.1% to clarithromycin and azithromycin. Only 13.3% of the strains showed susceptibility to the antibiotics tested. The greatest percentage of strains resistant to other antibiotics was found among the strains resistant to penicillin. Nine resistant phenotypes were detected.

Epidemiology and antifungal susceptibility of Candida species isolated from blood: results of a 2-year multicentre study in Spain

This study, included in the prospective survey of candidaemia in Europe supported by the European Confederation of Medical Mycology, presents the epidemiological and antifungal susceptibility results of 290 cases of candidaemia (80 in children <15 years old) reported from September 1997 to August 1999 by 19 Spanish hospitals. Presence of an intravenous catheter and previous antibiotic therapy were the most frequent risk factors. The percentages of the four most common species isolated (adults/children) were as follows: Candida albicans (46/36.2), C. parapsilosis (21.9/50), C. tropicalis (12.8/3.75), and C. glabrata (10.1/5). As initial therapy, fluconazole was preferred in adults (54%) and liposomal amphotericin B in children (58%). The 30-day mortality rate was 40.6%, and the species most frequently associated with a fatal outcome was C. krusei (60%). The rates of susceptibility to antifungal agents were as follows: amphotericin B, 91%; flucytosine, 99%; fluconazole, 93.6%; itraconazole, 87.4%; and voriconazole, 92%. These results provide baseline data for future epidemiological and susceptibility studies and for evaluating the impact of new antifungal agents on the distribution of species and the mortality rates associated with candidaemia in Spain.

[Study of in vitro activity of caspofungin on non-Candida albicans yeast strains determined by two methods: M27-A2 and EUCAST]

The in vitro activity of caspofungin against 147 non-Candida albicans yeasts isolated from blood culture was studied using two broth microdilution methods: M27-A2 and EUCAST. The minimum concentrations that produced a growth inhibition of > or = 50% and of 100% (MIC2 and MIC0, respectively) and a reduction in the number of viable colonies > or = 99% versus the initial inoculum (MFC) were determined for all strains. Caspofungin demonstrated good activity (MIC2 and MIC0 < or = 2 mg/l for 90% of the strains) against the species studied, including those that are normally resistant or have a high percentage of azole resistance (Candida krusei, Candida glabrata, Candida tropicalis). Nevertheless, the antifungal activity is lower (MFC < or = 2 mg/l in 73.47% of the strains with the M27-A2 method versus 62.59% with EUCAST), particularly for Candida guilliermondii and Candida parapsilosis. The two methods tested demonstrated good correlation for the MIC and lower correlation for the MFC. Essential agreement and concordance (+/- 2 log) between both methods for all strains tested were: 73.47% and 93.20% for MIC2; 74.8% and 91.84% for MIC0; and 57.1% and 74.15% for MFC, respectively. MICs determined by the EUCAST method are one- to three-fold dilutions lower, while the MFC are higher than those obtained by the M27-A2 method.

[Coverage of the 23-valent pneumococcal vaccine in those older than 64 years of age in the region of Castellon and Valencia, Spain]

The different serotypes of Streptococcus pneumoniae isolated from adults aged over 64 years in the Valencia and Castellon health region of Spain from June 1999 to December 2003 were analyzed. A total of 163 strains were evaluated; 58.3% were invasive, 47.24% were from respiratory source, and 4.9% were from exudates. The greatest percentage of samples was obtained from the group of patients aged 65 to 75 years (60.7%), while the lowest percentage was obtained from the group of patients aged over 85 years (10.4%). In the latter group, 53% of the strains were invasive and 29.4% were isolated from sputum. A total of 21 serotypes were identified, with the most common (> 3%) being: serotype 3 (22.1%); serotype 19 (12.9%); serotype 6 (12.3%); serotype 9 (8.6%); serotype 14 (10.4%); serotype 23 (8%); serotype 29 (3.7%); and serotype 18 (3.1%). Serotype 3 was the most common serotype found in all samples, with the exception of exudate, while serotype 23 was not isolated in blood. In this population group, the coverage of the 23-valent vaccine was 88.4%. Serotypes not included in this vaccine but isolated from invasive samples were serotypes 16, 24, 29 and 35. No changes were observed in serotype distribution over the 4-year period of the study. However, it is necessary to continue epidemiological monitoring to determine whether serotype substitution occurs.

[Usefulness of the E-test and its assay conditions in the study of the interaction of antifungal agents. A pilot study]

Preliminary data from a pilot study to assess the usefulness of the E-test in the study of antimycoctics are presented, evaluating assay and reproduction conditions. Results are compared with those obtained using the checkerboard method and mortality-time curves. Trials were carried out with a strain of Candida albicans (ATCC 90028). The E-test strips were combined in direct proportion, MIC-MIC, and in inverse proportion. The results showed that the method can be reproduced, is easy to carry out and may be suitable for the study of the in vitro interaction of antimycotics on yeast. The directly and inversely proportionate strip combination appeared to be the most suitable. At the prediffusion stage, the most highly water-soluble antimycotic should be used. The recommended time for prediffusion is one hour for water-soluble antimycotics, and two hours for non-water-soluble ones. The E-test showed good correlation with mortality-time curves. Nonetheless, in vivo correlation studies are required to determine the usefulness of the results in vitro and the most suitable method of measurement

[Serotypes and antibiotic susceptibility of Streptococcus pneumoniae in children in the health district of Valencia and Castellón, Spain: a multicenter, prospective trial]

A study was conducted to determine the serotypes, the coverage of the heptavalent conjugate vaccine (VCN 7-v) and the antibiotic susceptibility of Streptococcus pneumoniae in children (<15 years) in the health districts of the provinces of Castellon and Valencia, Spain, from June 1999 to December 2002. A total of 271 strains were evaluated, 15.5% of which were invasive, 63.5% were of respiratory origin and 22.5% were from conjunctival and otitic exudates; 67.2% of the strains were found in children younger than 2 years of age. The distribution of the serotypes showed slight changes according to age and the origin of the sample: the most common serotypes were 19, 6, 23, 14, 3, 9 and 11; however, in children younger than 2 years of age the order changed to 19, 6, 14 and 23, 9, 11 and 3, and in the invasive strains to 19, 6, 14, 3 and 23. A total of 27.2% of the stains were susceptible to the ten antibiotics tested. For penicillin, reduced susceptibility was found in 50.4% and high resistance in 5.8%; 98.3% were susceptible to ampicillin and amoxicillin-clavulanic acid, and 80.7% to cefuroxime; 52.5% were resistant to erythromycin and 43.7% to clindamycin. No strains were resistant to rifampicin, vancomycin, levofloxacin or cefotaxime. The most susceptible serotypes were 3 and 11, and the most resistant was 14 (which consistently showed resistance to an antibiotic), 19, 6 and 23. According to these data, the theoretical coverage of VCN 7-v would be 80.1% in children younger than 2 years and 73.43% in those aged 0-14 years.

[Resistance of HIV-1 to antiretroviral drugs in Valencia (Spain): mutations and susceptibility]

Resistance of HIV to antiretroviral drugs was studied in 210 samples taken in the last two years from patients at the Molecular Biology Unit of the Microbiology Department of the Hospital La Fe in Valencia, Spain. Once the viral load in plasma was determined, resistance was detected using complete gene sequencing for protease until position 3464 of the HIV-1 inverse transcriptase gene. The results were analyzed using the programs Omiga 1.2 (Oxford Molecular Group) and HR-ASAP 1.0 (Stanford University). The protease inhibitors the least affected by the presence of mutations leading to resistance were amprenavir (68.96% activity), and lopinavir (70.69% activity), and of the inverse transcriptase inhibitors, tenofovir (94.02% activity), D4T (74.62% activity) and 3TC (76.12% activity). The treatment combination with the greatest activity, based on the different mutations, was D4T + 3TC + NNRTI. To justify the persistence of viremia with relatively low genotypic resistance to antiretroviral drugs other variables must be considered, such as treatment compliance and the pharmacokinetics of the drugs.

[Haemophilus influenzae and betalactam resistance: description of bla TEM gene deletion]

The resistance to betalactam antibiotics in a total of 177 clinical isolates of Haemophilus influenzae, mostly from respiratory tract samples and characterized by their betalactamase production, was studied using the cephalosporin chromogenic assay and by detecting bla(TEM) and bla(ROB) genes. A substantial number of clinical isolates carrying the bla(TEM) gene, which presented a mutation consisting of the absence of a fragment of 136 base pairs, located upstream from the coding region including the 35 but not the 10 region of the promoter were found. This suggests that a new bla(TEM) promoter exists in these strains. This finding was associated with increased resistance to the antibiotics cefaclor and loracarbef compared with normal isolates. It was also found that 3.9% of the isolates carried the bla(ROB-1) gene.

[Fosfomycin]

Fosfomycin is an natural antibiotic with an epoxide structure and low molecular weight which acts in the first stage of peptidoglycan synthesis of the bacterial wall. It has a rapid bactericide effect, and a wide spectrum, including methicillin-resistant Staphylococcus aureus and intermediate glycopeptide-susceptible or -resistant enterococci. Over the years it has maintained its activity and has shown stable rates of resistance. It has synergistic action, which is additive or indifferent with glycopeptides, linezolid, quinupristin-dalfopristin, betalactams, aminoglycosides, ansamycines, nitroimidazoles and quinolones, without antagonism. It can be administered orally or parenterally in a wide range of doses, it does not bind to plasma proteins, and has a good distribution volume, reaching high concentrations in the interstitial fluid and tissues. It is eliminated in the kidneys in its active form without metabolites and is dialyzable. It has been used in a number of indications, including urinary, respiratory, intraabdominal, obstetric-gynecologic, central nervous system and osteoarticular infections, with satisfactory overall results in 80% of cases and minimal side effects. It does not cause important changes in the normal human flora. As additional effects it has the capacity to favor phagocytosis, act as an immunomodulator and protect human cells from cisplatin, cyclosporin, aminoglycoside, vancomycin, amphotericin B and polymixin toxicity. Oral fosfomycin is currently clearly indicated in urinary infections and gastroenteritis, and parenteral fosfomycin in high doses and in combination with other drugs in severe inhospital infections caused by problematic pathogens, including multiresistant staphylococci and enterococci, and in immunodepressed patients treated with nephrotoxic drugs.

[In vitro activity of posaconazole against yeasts isolated in blood cultures]

The in vitro activity of posaconazole against Candida species isolated from blood cultures and the influence of incubation time was studied and compared with that of fluconazole. A total of 112 isolates were studied: 32 Candida albicans, 33 C. parapsilosis, 17 C. tropicalis, 8 C. glabrata, 8 C. guilliermondii, 3 C. famata, 2 C. lusitaniae, 1 C. lipolytica, 1 C. inconspicua, 1 C. lambica, 3 Saccharomyces cerevisiae, 1 Blastoschizomyces capitatus, 1 Geotricum spp. and 1 Pichia omheri. The MIC was obtained using the M27-A microdilution method described by the NCCLS for Candida spp. and Cryptococcus neoformans. The species most susceptible to posaconazole were C. parapsilosis (MCI90 0.016 mg/l), C. guilliermondii (MIC90 0.12 mg/l), C. glabrata (MCI90 0.5 mg/l) and Candida spp. (MCI90 0.25 mg/l). However, this azole did not improve the activity of fluconazole against C. tropicalis (MIC90 8 mg/l) and C. albicans (MCI90 mg/l). The time of reading was important in the detection of resistance, as the number of strains resistant to fluconazole or posaconazole was higher at 48 hours than at 24 hours for C. albicans and C. tropicalis. All the other species of Candida were susceptible at both reading times.

[ROC curve analysis of factors predictive of response to treatment with interferon plus ribavirin in patients with chronic hepatitis C relapse after previous interferon treatment]

This study aimed to identify the factors predictive of response before the initiation of treatment and throughout the treatment period in patients with chronic hepatitis C relapse after treatment with interferon-a who were retreated with a standard regimen of interferon-a plus ribavirine and followed up for 40 months. Forty-four patients (40 with genotype 1, four without genotype 1) were included in the study. Four patients (genotype 1) were excluded because of adverse effects. The rate of maintained response was 55% (50% genotype 1, 100% non-genotype 1). The stage of histological damage (>2), glutamic-pyruvic transaminase (GPT) concentration (< or = 26 UI/l) and the association between the GPT concentration and the detection of the RNA-HCV in the first and third treatment months were the variables with an area under the ROC curve and a confidence interval >0.5. The probability of predicting a maintained response (negative predictive value) if the stage of histological lesion was <2 was 62.9%, while the positive predictive value was 100%. During the treatment, the disappearance of the RNA-HCV together with GPT values < or =26 in the first treatment month were the best predictive values. In this case, the negative predictive value was 78.3% and the positive predictive value was 76.5% (OR: 11.7, 2.6-52.2). Furthermore, the GPT value with the best predictive value (<26 UI/l) was a more effective predictor of the response to treatment than the normal value of the GPT. Finally, the GPT values >26 UI/l and the detection of RNA/HCV in the first or third treatment month were certain predictors of the absence of response but with low sensitivity (10-12%). It was concluded that is possible to predict the response to the combined treatment with an acceptable level of confidence, although not unequivocally. Ninety percent of the patients would be candidates for maintaining treatment for at least 6-12 months, while approximately 10% could undergo early interruption of treatment due to the absence of response.

Early infections in adult patients undergoing unrelated donor cord blood transplantation

Early transplant-related mortality after cord blood transplantation from unrelated donors (UD-CBT) is close to 50%, mainly due to infectious complications. We have studied the incidence and characteristics of early infections (before day 100) in a series of 27 adult patients (median age 30 years, range 16-46) undergoing UD-CBT at a single institution. All 27 patients experienced at least one infectious episode and 18 (66%) suffered a severe infection. Bacteremia occurred in 55% of patients (13 with Gram-positive and 11 with Gram-negative microorganisms). Eleven of 19 CMV-seropositive patients (58%) developed CMV antigenemia and one patient had CMV disease. Fungal infections were documented in three patients (11%), comprising invasive fungal infections in two cases and a localized esophagitis in one. Ten patients (37%) died before day 100 after transplantation. Infection was considered the primary cause of death in four patients (sepsis by Acinetobacter spp. bacteremia in three cases) and contributed to death in another four. The most striking findings in this series were the high incidence of, and mortality due to multiresistant Acinetobacter spp. and the low incidence of and lack of mortality due to CMV disease. This report confirms that infection is a major complication in adults undergoing UD-CBT.

Candidemia at a tertiary-care hospital: epidemiology, treatment, clinical outcome and risk factors for death

The demographic, clinical and microbiological data of patients with candidemia at the "Hopital Universitario La Fe", a tertiary-care hospital in Valencia, Spain, from 1995 to 1997 was analyzed retrospectively. Candida spp. were isolated in blood cultures from 145 patients, 32% of whom were children (25% of these were neonates). The most common species isolated was Candida albicans, followed by Candida parapsilosis, Candida krusei and Candida tropicalis. Risk factors for candidemia included underlying disease, therapy with broad-spectrum antibiotics and the presence of a central venous catheter. The majority of children were treated with amphotericin B, whereas 52% of adults received fluconazole. Overall mortality was 44% (30% in children and 50% in adults), and attributable mortality was 30% (24% in children and 33% in adults). Multivariate analysis indicated that neutropenia, corticosteroid therapy, lack of antifungal treatment, and failure to replace the central venous catheter were factors associated with candidemia-related death. Among the adult population, an APACHE II score greater than 15 predicted candidemia-related death.

Infectious complications in patients undergoing unrelated donor bone marrow transplantation: experience from a single institution

OBJECTIVE

To analyze the incidence and characteristics of documented infections in patients with hematologic malignancies undergoing unrelated donor bone marrow transplantation (UD-BMT).

METHODS

We studied the occurrence of infections in 22 patients with hematologic malignancies or severe aplastic anemia who underwent UD-BMT from April 1990 to December 2000. The median age was 26 years (range 13-46). Acyclovir-ganciclovir, co-trimoxazole, fluconazole-nystatin and ciprofloxacin were administered for anti-infectious prophylaxis.

RESULTS

We registered 61 infectious episodes. During the early post-transplant period, there were eight clinically documented infections (CDIs), four cases of fever of unknown origin (FUO), seven cases of bacteremia, two cases of cytomegalovirus (CMV) antigenemia, and one case of CMV disease. In the intermediate period (days 30-100 after BMT), there were nine cases of CMV antigenemia, three bacterial infections, two fungal infections, one case of disseminated toxoplasmosis, and one case of FUO. In the late period (day 100 and later), we documented 13 viral infections, eight bacterial infections, one CDI, and one case of invasive aspergillosis. Infections contributed to death in 10 of 17 patients. Citrobacter bacteremia and sepsis of unknown origin were the main causes of infectious mortality in the early period. Infection was the main cause of death in six of seven patients in the late period.

CONCLUSION

A high incidence of life-threatening infections and infection-related mortality was observed. A high rate of CMV infection in the early period, and death caused by multiresistant Gram-negative microorganisms in the late period, were the main findings in this series.

[Urinary infection]

The term urinary infection defines those processes located in the urinary tract due to the presence of microorganisms in the urine, particularly bacteria. Regardless the sex or age of the patient, they represent the second most frequent type of infection, after respiratory tract infections, not only in outpatients but also in hospitalized patients. There is an ongoing interest about the etiology and pathogenesis of urinary infections in order to identify the virulence-factor profiles of bacterial isolates and the characteristics of the infection-prone individuals. Urinary infections are caused by a wide range of pathogens, specially gramnegative rods (E. coli, P. mirabilis, Klebsiella). However, there is an increasing evidence of the role as pathogens of some microorganisms that have long been regarded as apathogenic like E. faecalis and the Staphylococcus group. The treatment of such infections represents a challenge for the future mainly in the fields of control of antimicrobial resistance and vaccine development.

[Retreatment with interferon plus ribavirin in chronic hepatitis C patients with genotype 1 who had no response or a relapse with a previous interferon treatment. Long term follow-up]

The aims of this study were twofold: i) to evaluate the sustained response rate at 6 months, at 12 months and at the end of the follow-up [(46.39 +/- 9.74 months) (range: 6-60 months)] in patients with chronic hepatitis C retreated with interferon-a (IFN-a) plus ribavirin for 6 months (group A), 12 months (group B), in patients with relapse and those with no response to a previous course of monotherapy with IFN-a; and ii) to evaluate changes in the histological liver lesion. One hundred and four patients (100 with genotype 1 and four without), 44 with relapse and 60 non-responders, were included. A total of 20.2% of the patients were excluded because of side effects. Fifty percent of the relapsing patients with genotype 1 showed a sustained response. The sustained response rate was higher in group B than in group A, whereas the rate for the relapsing patients was lower in group B than in group A (13/20 vs. 5/16; 7.2% vs. 61.5%; p <0.09 and p <0.009, respectively). However, 9.3% of the non-responding patients showed a sustained response (A/B: 2/2). The relapsing patients who had a genotype other than 1 showed a sustained response. The sustained response rate was constant throughout the follow-up, except in relapsing patients from group A (the late relapse rate was 28.6%). The viral load was not related to the response. The grade and stage of the histological lesion improved in patients with sustained response (n=20) and in one-third of the non-responding patients (n=45) (p <0.0001 and p <0.0001). IFN in combination with ribavirin was more effective in relapsing patients with genotype 1 at 12 months than in those at 6 months of treatment, whereas the effectiveness in non-responding patients was low. The sustained response evaluation at 6 months was reliable, except in relapsing patients with 6 months of treatment. The histological lesion improved significantly with combination antiviral therapy.