[Assessment of 2 automated microdilution techniques compared to an agar dilution method in determining sensitivity to fosfomycin in strains of carbapenem-resistant Pseudomonas aeruginosa]. / Valoración de 2 técnicas automatizadas de microdilución frente a dilución en agar en la determinación de la sensibilidad a fosfomicina en cepas de Pseudomonas aeruginosa resistentes a carbapenémicos.

Carbapenems-resistance in Pseudomonas aeruginosa isolates has been widely reported. Fosfomycin has been shown to act synergistically with other antimicrobials. The agar dilution method was approved for susceptibility testing for fosfomycin and Pseudomonas aeruginosa. However, broth microdilution methods are the basis of systems currently used in clinical microbiology laboratories. The results of this study indicate that these methods are acceptable as susceptibility testing methods for fosfomycin against these organisms.

[In vitro activity of fosfomycin, alone or in combination, against clinical isolates of carbapenem resistant Pseudomonas aeruginosa]. / Actividad in-vitro de fosfomicina, sola o en combinaciones, frente a aislamientos clínicos de Pseudomonas aeruginosa resistentes a carbapenémicos.

INTRODUCTION: The increase in microorganisms showing patterns of multi-drug resistance or even pan-drug resistance is of growing concern. Fosfomycin (FO) is well known to be active against a wide variety of microorganisms, including highly resistant strains of Pseudomonas aeruginosa (P. aeruginosa), and can also synergistically act with other molecules. METHODS: This study examines the in vitro activity shown by FO against 120 strains of carbapenem-resistant P. aeruginosa using an agar dilution and a gradient diffusion test. Possible synergistic effects of the combinations of FO/amikacin and FO/ciprofloxacin were also examined using E-test and time-kill techniques. RESULTS: According to the epidemiological cut-off value (ECOFF) issued by the European Committee on Antimicrobial Susceptibility Testing (EUCAST), our results indicate that over three-quarters of the strains tested would be susceptible to FO treatment, especially if combined with another antimicrobial. The FO/ciprofloxacin combination had a synergistic effect on 40% of the clinical isolates, while for FO/amikacin this effect was only observed in 12% of the isolates. CONCLUSION: The appearance of carbapenem-resistant P. aeruginosa strains requires the evaluation by combination therapy. This report suggests that the FO/ciprofloxacin combination can be useful, showing a synergistic effect in 40% of the isolates.

Identification of clinical yeasts by Vitek MS system compared with API ID 32 C.

We performed a clinical evaluation of the Vitek MS matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) system with the commercial database version 2.0 for rapid identification of medically important yeasts as compared with the conventional phenotypic method API ID 32 C. We tested 161 clinical isolates, nine isolates from culture collections and five reference strains. In case of discrepant results or no identification with one or both methods, molecular identification techniques were employed. Concordance between both methods was observed with 160/175 isolates (91.42%) and misidentifications by both systems occurred only when taxa were not included in the respective databases, i.e., one isolate of Candida etchellsii was identified as C. globosa by Vitek MS and two isolates of C. orthopsilosis were identified as C. parapsilosis by API ID 32 C. Vitek MS could not identify nine strains (5.14%) and API ID 32 C did not identify 13 (7.42%). Vitek MS was more reliable than API ID 32 C and reduced the time required for the identification of clinical isolates to only a few minutes.

[Linezolid resistant coagulase-negative Staphylococcus: phenotypical and genotypical characteristics and sensitivity to antibiotic combinations]. / Staphylococcus coagulasa negativos resistentes al linezolid: características fenotípicas, genotípicas y sensibilidad a combinaciones de antibióticos.

OBJECTIVE: We recovered 22 coagulase-negative staphylococci isolates in our hospital to study their identity, susceptibility, epidemiological profile, linezolid resistance mechanisms, and the possibilities of different antibiotic combinations. METHODS: Isolate identification was performed using mass spectrometry (Vitek-MS, bioMérieux). Susceptibility testing was carried out with the Vitek-2 system and the broth microdilution method according to CLSI guidelines. Pulsed-field gel electrophoresis (PFGE) was performed to analyze the genetic relationship between isolates. Linezolid resistance mechanisms were evaluated by PCR/sequencing: presence of cfr gene, point mutations in domain V of 23S ribosomal RNA and additional ribosomal mutations (in the rplC, rplD and rplV genes). The in vitro activity of linezolid was investigated alone and in combination with another three antibiotics acting on different cellular targets, using E-test strips. RESULTS: Twenty isolates were identified as Staphylococcus epidermidis, and 2 as Staphylococcus hominis. PFGE showed that isolates belonged to diverse clones, 21 of them presented mutations in the domain V region of 23S rRNA and the cfr gene was found in 54.5%. Prior administration of linezolid was documented in most of cases. Linezolid in combination with gentamicin showed a synergistic activity in 45.5% of isolates. CONCLUSIONS: Staphylococcus epidermidis was the most prevalent linezolid-resistant coagulase-negative staphylococci. All isolates showed increased MIC values compared to other anti-staphylococcal drugs and several linezolid resistance mechanisms. Our data suggest that linezolid plus gentamicin could be a synergistic combination against linezolid-resistant coagulase-negative staphylococci.

Recurrent episodes of candidemia due to Candida glabrata with a mutation in hot spot 1 of the FKS2 gene developed after prolonged therapy with caspofungin.

We report two episodes of recurrent candidemia caused by echinocandin-resistant Candida glabrata in a 69-year-old patient who underwent repeated abdominal surgery. In the first episode of candidemia, an echinocandin-susceptible Candida glabrata strain was isolated, and the patient was treated with caspofungin. The isolates from the later episodes showed resistance to echinocandins. Analysis of the HS1 region of the FKS2 gene showed the amino acid substitution S663P. Microsatellite analysis demonstrated a strong genetic relationship between the isolates.

[Diseases associated with bloodstream infections caused by the new species included in the old Streptococcus bovis group]. / Cuadros clínicos asociados a bacteriemia causada por las nuevas especies incluidas en el antiguo grupo Streptococcus bovis.

OBJECTIVE: We sought to identify possible diseases associated with bloodstream infections caused by new species of S. bovis group isolated in blood cultures and by studying patient records METHODS: Forty-four consecutive blood culture isolates initially designated S. bovis were further characterised using phenotypic methods Patient records were examined. RESULTS: We identified 15 Streptococcus gallolyticus subsp. gallolyticus, 24 Streptococcus gallolyticus subsp. pasteurianus, and 5 Streptococcus infantarius isolates in 44 BSI episodes. CONCLUSIONS: The association between S. bovis bacteraemia and endocarditis and/or colon carcinoma is highly dependent on the causative species. Streptococcus gallolyticus subsp. gallolyticus is a surrogate for endocarditis and/or bowel disease, whereas Streptococcus gallolyticus subsp. pasteurianus is a surrogate for hepato-biliary disease.

In vitro activity of ceftaroline in combination with other antimicrobials active against Staphylococcus spp. / Actividad in vitro de la combinación de ceftarolina con otros antimicrobianos activos frente a Staphylococcus spp.

INTRODUCTION: We evaluated the in vitro activity of the combination of ceftaroline with daptomycin, linezolid and vancomycin against methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus (CNS). MATERIAL AND METHODS: We analysed 70 staphylococcal strains (31 S. aureus and 39 CNS) with the Etest using the MIC:MIC ratio method and calculation of fractional inhibitory concentration indexes. RESULTS: The combination of ceftaroline with daptomycin showed an additive effect (53.2%) and synergy (6.6%) against methicillin-susceptible S. aureus, and an additive effect (81.2%) against methicillin-resistant S. aureus (MRSA). This combination also showed an additive effect against 33% of linezolid-susceptible CNS and was not synergistic against linezolid-resistant CNS. The combination of ceftaroline with vancomycin was synergistic (87%) and ceftaroline with linezolid was additive (37%) against MRSA. CONCLUSIONS: The combinations of ceftaroline with daptomycin, vancomycin or linezolid showed additive and/or synergistic effects against methicillin-resistant Staphylococcus.

[Comparison between agar dilution and three other methods for determining the susceptibility of 228 clinical isolates of non-fermenting gram-negative rods]. / Comparación entre dilución en agar y otras 3 técnicas para la determinación de la sensibilidad de 228 aislamientos clínicos de bacilos gramnegativos no fermentadores.

INTRODUCTION: Susceptibility testing for non-fermenting gram-negative rods (NFGNR) is problematic; valid methods are needed for this purpose. METHODS: In this study, 228 NFGNR clinical isolates were evaluated, including 85 Acinetobacter spp., 80 Stenotrophomonas maltophilia, 50 Pseudomonas aeruginosa, and 13 other species (8 Ralstonia pickettii and 5 Burkholderia cepacia). Agar dilution was used as the reference method, and results were compared with those obtained by disk diffusion, Etest, and microdilution performed with the VITEK 2 Compact System. RESULTS: The disk method was unacceptable for S. maltophilia and P. aeruginosa, in the latter organism, mainly because of poor agreement in the colistin results. Nonetheless, the disk method is valid for Acinetobacter spp. and the remaining NFGNRs. The VITEK 2 Compact System yielded poor results for piperacillin-tazobactam, tigecycline, and ceftazidime in S. maltophilia. There were minor discrepancies with the VITEK 2 Compact system and the Etest for tigecycline in Acineobacter spp. and S. maltophilia, likely because of the differing composition of the Muller-Hinton agar lots. Hence, Etest results should be interpreted with caution. CONCLUSION: The disk diffusion method is inadequated for S. maltophilia. This method is unacceptable for testing colistin in P. aeruginosa. The methods Vitek 2 Compact System and Etest show minor discrepancies for testing S. maltophilia and Acinetobacter spp. for tigecycline.

Evaluation of sera with a low signal to cut-off ratio using two chemiluminescent assays for detecting Hepatitis C Virus, and their correlation with the detection of Viral RNA. / Valoración de sueros con bajo índice S/CO utilizando 2 sistemas de quimioluminiscencia para la detección de anticuerpos frente al virus de la hepatitis C y su correlación con la detección de ARN viral.

OBJECTIVE: All commercial assays used to measure the presence of Hepatitis C virus (HCV) antibodies set cut-off points to categorise the results, but the problem of false positive results in screening hepatitis C sera is well known. The aim of this study was to evaluate the results obtained by two chemiluminescent assays in selected sera, and compare these results with the detection of viral RNA in the specimens studied. MATERIAL AND METHODS: Two hundred reactive sera (positive) were selected, although with a low signal to cut-off ratio (S/CO), were selected, using two chemiluminescent assays and were then subjected to genome amplification. RESULTS AND DISCUSSION: Viral RNA could be only be detected in 8 (4%) of the selected specimens. Taking these results into account, we believe that the design of the current chemiluminescent assays do not provide sufficient specificity when they are used as the only tests for the diagnosis of hepatitis C.

Clostridium perfringens bacteraemia, an analysis of 28 cases over 10 years in a university hospital of Madrid. / Bacteriemia por Clostridium perfringens. Un análisis de 28 casos durante 10 años en un hospital universitario de Madrid.

Bacteraemia caused by anaerobic bacteria is rare in the hospital setting. The Clostridium genus is the second most common cause of these infections, particularly Clostridium perfringens, which has a high mortality rate. However, reviews in the literature of these infections are scarce. The aim of this study was to retrospectively document the incidence, clinical characteristics and risk factors involved in the acquisition of bacteraemia caused by C. perfringens among patients treated at our hospital over a 10-year period. Twenty-eight patients with C. perfringens bacteraemia were included in the study. We evaluated pre-existing comorbidities, the source of bacteraemia, clinical features, the antimicrobial treatment administered and patient outcome. C. perfringens bacteraemia occurs rarely in our setting, but with a very high mortality rate. This rate is associated with old age and pre-existing, largely gastrointestinal malignancies. It presents with few specific symptoms but requires rapid and appropriate diagnosis and treatment to reduce the high mortality of this infection.

In vitro activity of linezolid and 12 other antimicrobials against coryneform bacteria.

OBJECTIVES: To compare the in vitro activity of linezolid with 12 other antimicrobials against 190 strains of the coryneform bacteria, including 60 strains of C. amycolatum, 30 of C. striatum, 30 of C. jeikeium, 10 of C. urealyticum, 20 of B. casei, 20 of D. hominis and 20 of T. otitidis. METHODS: Minimum inhibitory concentrations (MICs) and time-death curves were carried out according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI). RESULTS: Linezolid was very active against the 130 strains of the Corynebacterium species studied. Only the glycopeptides showed similar efficacy. In contrast, penicillin G, ampicillin, macrolides, lincosamides, fluoroquinolones and aminoglycosides showed generally high MICs. Among the beta-lactams, only imipenem was active against the majority of strains of C. striatum and C. amycolatum, and, approximately half of the C. jeikeium and C. urealyticum isolates. Both Dermabacter hominis and Brevibacterium casei showed marked resistance against most of the antimicrobials tested, while Turicella otitidis only showed high MICs against macrolides and clindamycin. For all of them, linezolid, vancomycin and teicoplanin proved effective. The time-death curves showed linezolid to behave as a bacteriostatic agent (approximately 90% death rate). Such activity was more accentuated for C. amycolatum and C. striatum (reduction of 1.3 and 1.7log(10)CFU/mL, respectively) than for C. jeikeium and C. urealyticum (reduction of 1.0 and 0.8log(10), respectively). CONCLUSIONS: Our results indicate that linezolid is active against coryneform bacteria. The efficacy of linezolid is equal to or even superior to that of the glycopeptides.

[Outbreak of Trichophyton tonsurans ringworm in a health area of the Community of Madrid (Spain)]. / Epidemia de tiña por Trichophyton tonsurans en un área sanitaria de la Comunidad de Madrid (España).

BACKGROUND: Trichophyton tonsurans is a dermatophyte fungus that can cause ringworm outbreaks. In our health area in September 2013, two cases of T. tonsurans ringworm were diagnosed in children who lived in a Children's Centre. AIMS: To determine the origin and extent of the outbreak. METHODS: Mycological cultures of scalp and skin samples from the contacts of the diagnosed cases were performed, as well as environmental samples from the Children's Centre. The patients started with a treatment for their ringworm, and an environmental disinfection of the centre was performed. RESULTS: Twelve cases of ringworm were detected, along with three asymptomatic scalp carriers of T. tonsurans among 20 children in the Centre. The index case was a resident in whose family, that had just returned from their country of origin, Nigeria, three cases of ringworm were diagnosed. From November 2013 to February 2014 another five cases of ringworm were diagnosed among schoolmates of three cases from the Children's Centre. CONCLUSIONS: The antifungal treatment of the children resulted in the mycological and clinical resolution, and from February to November 2014 no other cases of ringworm by T. tonsurans in the same health area were diagnosed.

[Seroprevalence of hepatitis E virus in patients with hepatitis C and / or infected with HIV]. / Seroprevalencia del virus de la hepatitis E en pacientes con hepatitis C y/o infección por el virus de la inmunodeficiencia humana.

INTRODUCTION: Hepatitis E virus (HEV) can cause chronic infection and cirrhosis. The seroprevalence data of anti-HEV IgG in the patients infected with HIV or with chronic liver disease are scarce. METHODS: To document the seroprevalence of HEV infection in HIV patients or with chronic liver disease population, a retrospective study in serum samples from 625 patients was carried on: 200 HIV infected, 200 HCV infected, 25 coinfected by HIV and HCV and 200 healthy controls. Anti-HVE IgG antibodies were determined in serum samples by a commercial immunoassay (EIA) and all positive samples were studied further for the presence of anti-HEV IgM antibodies (HEV IgM 3.0; DiaSorin, Turín, Italy). Positive HEV IgM antibody specimens were examined for HEV RNA by polymerase chain reaction. RESULTS: Anti-HEV IgG were reactive in 25 (12.5%) of the 200 HIV-infected patients, in 47 out of 200 HCV infected patients (23.5%), 10 out of 25 coinfected HIV-HCV group (40%) and 24 out of 200 healthy controls (12%). According to EIA anti-HEV IgM, 11 patients could be considered as acute hepatitis E cases but in only one of them was confirmed recent HEV infection by RT-PCR. CONCLUSIONS: The higher seroprevalence was found in HIV-HCV coinfected patients. The only patient with HEV RNA was HIV-HCV coinfected.

Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry for identifying respiratory bacterial pathogens: a fast and efficient method.

Mass spectrometry has become a reference resource for identifying microorganisms in clinical microbiology services. One hundred and fifty one clinical isolates were selected from respiratory specimens routinely identified as Streptococcus pneumoniae (43), Haemophilus influenzae (64) and Moraxella catarrhalis (44). These identifications were compared with other phenotypical methods and mass spectrometry (MALDI-TOF-MS Vitek). Result discrepancies were assessed by 16S rRNA sequencing. Thirty-eight of the 43 strains of S. pneumoniae (86%) were identified as such using phenotypical methods and spectrometry. In 5 cases, MALDI-TOF identified 4 of them as Streptococcus pseudopneumoniae and 1 as S. mitis/oralis. Forty-eight of the 64 strains were identified as H. influenzae (75%) using biochemical identification systems and automated identification systems, whereas MALDI-TOF-MS Vitek identified 51 strains (79%) as such. Conventional methods and spectrometry identified all the 40 strains tested (100%) as M. catarrhalis. All strains with discrepant results were sequenced, and in all cases, the identification obtained by spectrometry was confirmed. The results obtained in this study show that mass spectrometry provides identification of these bacteria faster and in a more reliable way than those based on conventional phenotypical methods.

[Serological markers of Spanish and immigrant pregnant women in the south of Madrid during the period 2007-2010]. / Marcadores serológicos de gestantes españolas e inmigrantes en un área del sur de Madrid durante el periodo 2007-2010.

OBJECTIVE: The prevalence and evolution of the markers including in the serologic profile of pregnant woman was studied in our hospital during a period of 4 years. MATERIAL AND METHODS: A retrospective study of the prevalence of antibodies against Treponema pallidum, human immunodeficiency virus (HIV), Toxoplasma gondii, rubeola virus and hepatitis B virus (HBV), was performed in our hospital among Spanish and immigrant pregnant women, from January 2007 to December 2010. RESULTS: A total of 8,012 pregnant were studied, 2,752 (34.2%) of them were foreign. The non-treponemal tests (RPR) were positive in 40 (0.49%) women, being the prevalence slightly superior in foreigners than in natives (0.8 as opposed to 0.3%). The IgG anti-T. gondii global prevalence was 23,35% (1,874 patients). In Spanish pregnant this prevalence was 18%, and 33.8% in the immigrant women. Almost the total of Spanish pregnant (99.5%) displayed IgG antibodies against rubeola virus whereas in the foreigners this rate was 61.6%. The presence of HBsAg for HBV was tested in 86.6% of pregnant women (6,939/8,012), being positive the 0.75% (59 patients), with a prevalence in foreigners greater than in Spanish (1.65 as opposed to 0.4%). Antibodies anti-HVI were detected in 22 patients (0.22%), being the prevalence 0.15% among the Spanish and 0.51% among the foreigners.