Simultaneous and divergent evolution of resistance to cephalosporin/β-lactamase inhibitor combinations and imipenem/relebactam following ceftazidime/avibactam treatment of MDR Pseudomonas aeruginosa infections

OBJECTIVES

To describe and characterize the emergence of resistance to ceftolozane/tazobactam, ceftazidime/avibactam and imipenem/relebactam in a patient receiving ceftazidime/avibactam treatment for an MDR Pseudomonas aeruginosa CNS infection.

METHODS

One baseline (PA1) and two post-exposure (PA2 and PA3) isolates obtained before and during treatment of a nosocomial P. aeruginosa meningoventriculitis were evaluated. MICs were determined by broth microdilution. Mutational changes were investigated through WGS. The impact on β-lactam resistance of mutations in blaPDC and mexR was determined through cloning experiments and complementation assays.

RESULTS

Isolate PA1 showed baseline resistance mutations in DacB (I354A) and OprD (N142fs) conferring resistance to conventional antipseudomonals but susceptibility to ceftazidime/avibactam, ceftolozane/tazobactam and imipenem/relebactam. Post-exposure isolates showed two divergent ceftazidime/avibactam-resistant phenotypes associated with distinctive mutations affecting the intrinsic P PDC β-lactamase (S254Ins) (PA2: ceftolozane/tazobactam and ceftazidime/avibactam-resistant) or MexAB-OprM negative regulator MexR in combination with modification of PBP3 (PA3: ceftazidime/avibactam and imipenem/relebactam-relebactam-resistant). Cloning experiments demonstrated the role of PDC modification in resistance to ceftolozane/tazobactam and ceftazidime/avibactam. Complementation with a functional copy of the mexR gene in isolate PA3 restored imipenem/relebactam susceptibility.

CONCLUSIONS

We demonstrated how P. aeruginosa may simultaneously develop resistance and compromise the activity of new β-lactam/β-lactamase inhibitor combinations when exposed to ceftazidime/avibactam through selection of mutations leading to PDC modification and up-regulation of MexAB-OprM-mediated efflux.

Expression profile of microRNAs related with viral infectivity, inflammatory response, and immune activation in people living with HIV

Objective

To evaluate the serum expression of microRNAs (miRNAs) with ability to modulate the human immunodeficiency (HIV) replication or inflammatory status in people living with HIV (PLWH).

Methods

Forty healthy controls and two groups of PLWH were evaluated: (a) Group 1 (n = 30), patients with detectable viral load at inclusion, analyzed before receiving antiretroviral therapy (ART) and 12 months after initiating it; (b) Group 2 (n = 55), PLWH with prolonged undetectable viral load. Intestinal barrier disruption (I-FABP) and bacterial translocation (16S rDNA) markers, inflammatory markers such as interleukin (IL)-6 and sCD163, immune activation and expression of specific miRNAs were evaluated.

Results

Serum concentrations of I-FABP, 16S rDNA, IL-6, sCD163 and activated T lymphocytes were increased in PLWH. Serum miR-34a was overexpressed at inclusion and remained elevated after ART. The expression of the remaining miRNAs that modulate HIV infectivity (miR-7, mir-29a, miR-150, and miR-223) was similar in PLWH and controls. Related to miRNAs implicated in inflammation (miR-21, miR-155, and miR-210), significant overexpression were observed in miR-21 and miR-210 levels in untreated PLWH, but levels were restored in those patients treated for a long period.

Conclusion

A sustained overexpression of miR-34a was detected even after prolonged HIV controlled replication. miR-21 and miR-210 can be considered new markers of inflammation with high sensitivity to its modifications.

Molecular mechanisms driving the in vivo development of OXA-10-mediated resistance to ceftolozane/tazobactam and ceftazidime/avibactam during treatment of XDR Pseudomonas aeruginosa infections

BACKGROUND

The development of resistance to ceftolozane/tazobactam and ceftazidime/avibactam during treatment of Pseudomonas aeruginosa infections is concerning.

OBJECTIVES

Characterization of the mechanisms leading to the development of OXA-10-mediated resistance to ceftolozane/tazobactam and ceftazidime/avibactam during treatment of XDR P. aeruginosa infections.

METHODS

Four paired ceftolozane/tazobactam- and ceftazidime/avibactam-susceptible/resistant isolates were evaluated. MICs were determined by broth microdilution. STs, resistance mechanisms and genetic context of β-lactamases were determined by genotypic methods, including WGS. The OXA-10 variants were cloned in PAO1 to assess their impact on resistance. Models for the OXA-10 derivatives were constructed to evaluate the structural impact of the amino acid changes.

RESULTS

The same XDR ST253 P. aeruginosa clone was detected in all four cases evaluated. All initial isolates showed OprD deficiency, produced an OXA-10 enzyme and were susceptible to ceftazidime, ceftolozane/tazobactam, ceftazidime/avibactam and colistin. During treatment, the isolates developed resistance to all cephalosporins. Comparative genomic analysis revealed that the evolved resistant isolates had acquired mutations in the OXA-10 enzyme: OXA-14 (Gly157Asp), OXA-794 (Trp154Cys), OXA-795 (ΔPhe153-Trp154) and OXA-824 (Asn143Lys). PAO1 transformants producing the evolved OXA-10 derivatives showed enhanced ceftolozane/tazobactam and ceftazidime/avibactam resistance but decreased meropenem MICs in a PAO1 background. Imipenem/relebactam retained activity against all strains. Homology models revealed important changes in regions adjacent to the active site of the OXA-10 enzyme. The blaOXA-10 gene was plasmid borne and acquired due to transposition of Tn6746 in the pHUPM plasmid scaffold.

CONCLUSIONS

Modification of OXA-10 is a mechanism involved in the in vivo acquisition of resistance to cephalosporin/β-lactamase inhibitor combinations in P. aeruginosa.

Molecular and biochemical insights into the in vivo evolution of AmpC-mediated resistance to ceftolozane/tazobactam during treatment of an MDR Pseudomonas aeruginosa infection

BACKGROUND

Pseudomonas aeruginosa may develop resistance to novel cephalosporin/β-lactamase inhibitor combinations during therapy through the acquisition of structural mutations in AmpC.

OBJECTIVES

To describe the molecular and biochemical mechanisms involved in the development of resistance to ceftolozane/tazobactam in vivo through the selection and overproduction of a novel AmpC variant, designated PDC-315.

METHODS

Paired susceptible/resistant isolates obtained before and during ceftolozane/tazobactam treatment were evaluated. MICs were determined by broth microdilution. Mutational changes were investigated through WGS. Characterization of the novel PDC-315 variant was performed through genotypic and biochemical studies. The effects at the molecular level of the Asp245Asn change were analysed by molecular dynamics simulations using Amber.

RESULTS

WGS identified mutations leading to modification (Asp245Asn) and overproduction of AmpC. Susceptibility testing revealed that PAOΔC producing PDC-315 displayed increased MICs of ceftolozane/tazobactam, decreased MICs of piperacillin/tazobactam and imipenem and similar susceptibility to ceftazidime/avibactam compared with WT PDCs. The catalytic efficiency of PDC-315 for ceftolozane was 10-fold higher in relation to the WT PDCs, but 3.5- and 5-fold lower for piperacillin and imipenem. IC50 values indicated strong inhibition of PDC-315 by avibactam, but resistance to cloxacillin inhibition. Analysis at the atomic level explained that the particular behaviour of PDC-315 is linked to conformational changes in the H10 helix that favour the approximation of key catalytic residues to the active site.

CONCLUSIONS

We deciphered the precise mechanisms that led to the in vivo emergence of resistance to ceftolozane/tazobactam in P. aeruginosa through the selection of the novel PDC-315 enzyme. The characterization of this new variant expands our knowledge about AmpC-mediated resistance to cephalosporin/β-lactamase inhibitors in P. aeruginosa.

HIV antibodies level as a marker of HIV persistence: the role of hepatitis C virus coinfection

Human immunodeficiency virus (HIV) antibodies have been proposed as a measure of the size of the HIV reservoir. The aim of our study is to quantify the anti-HIV antibodies level in a cohort of people living with HIV (PLWH), stratified based on the presence of continuous undetectable HIV viral load and the co-existence of hepatitis C virus infection. A sample of 229 HIV-monoinfected (n = 114) or HIV/HCV-coinfected [either with resolved HCV infection (n = 75) or active HCV coinfection (n = 40)] patients, followed up a median of 34 (IQR 20-44) months, was studied. Anti-HIV index was obtained as the 1:800 dilution of HIV antibodies. CD4+ T cell count, time with undetectable HIV viral load, annual increase of CD4+ T cell count, anti-HCV therapy, and diagnosis of cirrhosis were analyzed. Patients with a continued suppressed HIV viral load had significant lower anti-HIV index compared with those with virologic failure during the follow-up. Significant higher CD4+ T cell increase was observed in those with a lower anti-HIV index. HIV-monoinfected patients showed an anti-HIV index significantly lower than patients with HCV coinfection. Resolved HCV infection after interferon-based therapy, but not with direct acting antivirals, was associated with a lower anti-HIV index. HIV/HCV-coinfected patients showed higher HIV antibodies level when compared with HIV-monoinfected individuals. A decrease in anti-HIV index in HIV/HCV-coinfected patients was detected when a sustained virological HCV response was obtained after interferon-based therapy, in possible relation with the direct or indirect effect of interferon on PLWH CD4 T cells.

HTLV-1 infection in solid organ transplant donors and recipients in Spain

Background

HTLV-1 infection is a neglected disease, despite infecting 10–15 million people worldwide and severe illnesses develop in 10% of carriers lifelong. Acknowledging a greater risk for developing HTLV-1 associated illnesses due to immunosuppression, screening is being widely considered in the transplantation setting. Herein, we report the experience with universal HTLV testing of donors and recipients of solid organ transplants in a survey conducted in Spain.

Methods

All hospitals belonging to the Spanish HTLV network were invited to participate in the study. Briefly, HTLV antibody screening was performed retrospectively in all specimens collected from solid organ donors and recipients attended since the year 2008.

Results

A total of 5751 individuals were tested for HTLV antibodies at 8 sites. Donors represented 2312 (42.2%), of whom 17 (0.3%) were living kidney donors. The remaining 3439 (59.8%) were recipients. Spaniards represented nearly 80%.

Overall, 9 individuals (0.16%) were initially reactive for HTLV antibodies. Six were donors and 3 were recipients. Using confirmatory tests, HTLV-1 could be confirmed in only two donors, one Spaniard and another from Colombia. Both kidneys of the Spaniard were inadvertently transplanted. Subacute myelopathy developed within 1 year in one recipient. The second recipient seroconverted for HTLV-1 but the kidney had to be removed soon due to rejection. Immunosuppression was stopped and 3 years later the patient remains in dialysis but otherwise asymptomatic.

Conclusion

The rate of HTLV-1 is low but not negligible in donors/recipients of solid organ transplants in Spain. Universal HTLV screening should be recommended in all donor and recipients of solid organ transplantation in Spain. Evidence is overwhelming for very high virus transmission and increased risk along with the rapid development of subacute myelopathy.

Sterility assurance of technetium-99m radiopharmaceuticals: no specific air conditions are required for their preparation, storage and dispensation

BACKGROUND

The aim of this study was to ascertain whether the extemporaneous technetium-99m radiopharmaceuticals - prepared by closed procedures - maintain or not sterility throughout their lifespan regardless the quality of the environmental air where they are prepared, stored and dispensed, provided that the basic aseptic rules for closed procedures are followed.

METHODS

Three different types of assays were performed in this study: 1) sterility tests of each and every one of the vials with the remains of technetium-99m radiopharmaceuticals, which have been prepared in our hospital radiopharmacy during three years without any special environmental air conditions; 2) integrity tests of punctured rubber plug closures using both microbial challenge testing and dye ingress testing; and 3) simulation of the dispensing process using a liquid growth medium.

RESULTS

Sterility tests of more than 6,000 vials with the remains of technetium-99m radiopharmaceuticals - prepared without any special ambient air conditions - were performed, all of them with a negative result (no growth of microorganisms occurs). The integrity of punctured rubber plugs closure was sufficiently proven under extreme conditions by two different methods. The maintenance of sterility during the dispensing process of technetium-99m radiopharmaceuticals was also proven by simulation of the dispensing process using a liquid growth medium.

CONCLUSIONS

This study strongly supports that it is not necessary any special ambient air conditions to prepare, store and dispense extemporaneous technetium-99m radiopharmaceuticals in order to preserve their sterility when the basic aseptic rules for closed procedures are followed.

A prospective survey of Aspergillus spp. in respiratory tract samples: Species identification and susceptibility patterns

We analyzed the species distribution and susceptibility patterns of 433 strains of Aspergillus spp. isolated from respiratory samples of 419 in-patients included in multicenter prospective study (FUNGAE-IFI) between July 2014 and October 2015. Identification was carried out by conventional methods at each participating center and by molecular sequencing of a portion of the β-tubulin gene at one of the centers. In vitro susceptibility was evaluated by broth microdilution methods and using the E-test (for cryptic species). Species identified included 249 A. fumigatus sensu stricto, 60 A. terreus sensu stricto, 47 A. flavus sensu stricto, 44 A. tubingensis, 18 A. niger sensu stricto , five A. nidulans sensu stricto, three A. tamarii, two A. calidoustus, two A. carneus, one A. acuelatus, one A. carbonarius, and one A. sydowii. Cryptic species were found in 12.5% of isolates (n = 54). The frequency of non-wild-type isolates for amphotericin B was 3.4% (n = 15) of the isolates tested and for azoles 3% (n = 10). None of the Aspergillus spp. were non-wild type to echinocandins. Of the 54 cryptic species only two strains were non-wild-type strains by microdilution method (3.7%) (two A. tubingensis, one to amphotericin B and another one to voriconazole) and by E-test method five strains of A. tubingensis showed high minimal inhibitory concentration (MIC) to amphotericin B (11.4%) and five to azoles (12.1%), one A. calidoustus strain showed high MICs for three azoles (50%), A. carneus to itraconazole (100%) and A. sydowii to amphotericin B and itraconazole (100%). These results provide relevant information on susceptibility patterns, frequency, and epidemiology of species involved in respiratory tract samples and of the incidence of recently described cryptic species.

Co-Occurrence of mcr-1 and qnrS1 on an IncHI2 Plasmid in Clinical Isolates of Salmonella Typhimurium in Spain

Salmonella enterica is a well-adapted zoonotic bacterium associated to cases of gastroenteritis and bacteremia with increased morbidity and mortality. In this study, three isolates of Salmonella Typhimurium obtained from human clinical samples, showing colistin resistance and low-level resistance to quinolones, have been genetically characterized. We detected the co-occurrence of mcr-1 and qnrS1 on a single IncHI2 plasmid in isolates of Salmonella Typhimurium obtained from Spanish children without a travel history. The multiresistant region contained numerous resistance genes. Isolates were clonally related, which suggests the presence of these clones in the community and the potential to cause outbreaks affecting the most susceptible population. It is necessary to monitor the presence of these plasmid-mediated resistance genes in human European strains of Salmonella spp. because of the risk of producing outbreaks of community-acquired infections.

Staphylococcus aureus carriage in older populations in community residential care homes: Prevalence and molecular characterization of MRSA isolates

INTRODUCTION

The epidemiology of S. aureus depends on conditions in specific populations. Few studies of S. aureus colonization in the older population have been performed in Spain. The aim of this study was to determine the prevalence of methicillin-resistant S. aureus (MRSA) colonization and its molecular epidemiological characteristics in an institutionalized population in community residential care homes in Cadiz, Spain.

METHODS

A cross-sectional epidemiological study was conducted in three residential care homes for older people. Axilla and nostril samples were tested. Identification of S. aureus and antimicrobial susceptibility testing were by MALDI-TOF and MicroScan panels. MRSA strains were subjected to SCCmec typing, multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). The presence of Panton-Valentine leukocidin (PVL) genes was determined by PCR in all S. aureus strains.

RESULTS

A total of 293 residents were included. Fifty-one residents (17.4%) were colonized with methicillin-sensitive S. aureus (MSSA) and 11 (3.8%) with MRSA. Resistance to at least two aminoglycosides was observed in 25.4% of MSSA and 90.9% and of MRSA isolates, and resistance to levofloxacin in 80.3% of MSSA and 100% of MRSA isolates. SCCmecIV was detected in all isolates and all except one (ST-125) were ST-8. None of the S. aureus isolates were positive for PVL.

CONCLUSIONS

A low rate of S. aureus carriage was detected and the prevalence of MRSA was very low. ST8-MRSA-IVc was the dominant clone, and only one strain belonged to ST125-MRSA-IVc. We found MRSA transmission within the residential care homes and a very high rate of quinolone resistance in MSSA and MRSA.

Approach of clinicians to candiduria and related outcome in the elderly

OBJECTIVE

Candiduria is increasingly frequent in hospitalized debilitated patients. We aimed to evaluate the approach of clinicians to candiduria in the oldest old, and its effect on clearance and mortality.

MATERIAL AND METHODS

An observational study without intervention was carried out during 2012 and 2013 in three Spanish hospitals over patients with nosocomial candiduria aged 80 and over. Following a diagnostic algorithm, we assessed the appropriateness of antifungal therapy and analyzed the impact of the clinical approach (antifungal therapy, antibiotics discontinuation and catheter removal or replacement) on the outcome (mortality at 60 days and resolution, persistence or recurrence of candiduria).

RESULTS

Hundred and forty eight patients were included. Symptomatology was attributable to candiduria in 31 instances and 19 asymptomatic patients were found at risk of developing candidemia. In response to culture-results, 77 (52%) of patients were treated with antifungals, mainly fluconazole (97.4%). The use of pharmacological therapy was appropriate (P<0.05) but subtherapeutical doses of fluconazole were widely used and follow-up samples were scarcely submitted. At 60 days of diagnosis the mortality was high (29.7%). The replacement or removal of the catheter resulted in a decrease in mortality and the use of antifungal treatment was associated with recurrence (P<0.05).

CONCLUSIONS

In the absence of clinical practice guidelines with enough evidence, our study suggests that catheter removal should always be tried in the elderly with candiduria, since it reduces the mortality. The repetition of culture should help to better characterize the asymptomatic episodes, which are predominant, and to reduce the use of antifungals.

Candiduria: impacto ecológico de los antibióticos

[No disponible]

Nosocomial Candiduria in the Elderly: Microbiological Diagnosis

Candiduria is associated with high morbidity, mortality, and long hospitalization, involving high costs for the healthcare system. The use of increasingly aggressive treatments has prolonged the lives of patients susceptible to candiduria, namely the immunosuppressed, the premature, and the elderly. Our objective was to evaluate the incidence of nosocomial candiduria and the implicated species in hospitalized patients aged over 80 years old from three Spanish centers during 2012 and 2013. Urine samples received from these patients were cultured and analyzed by flow cytometry in search of leukocyturia, hematuria, proteinuria, and microbial nitrate reductase activity. The isolated yeast species were identified microscopically, by germ tube formation in serum, colony morphology after subculture onto CHROMagar Candida (Becton-Dickinson, UK), assimilation of carbon compounds ID32C (bioMérieux, France), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDITOF) (Bruker Daltonics, Germany) and, in case of inconsistency, by sequencing of the ITS regions of ribosomal DNA (ITS1-5, 8S-ITS2). Susceptibility tests were also performed. The incidence of candiduria in the elderly population was 10.3%. A total of 155 strains of yeasts were isolated. The predominant species was Candida albicans, followed by Candida glabrata and then Candida tropicalis. Several infrequent species were found; among them, the first isolate of candiduria-producing Candida pulcherrima described in the literature. Our finding should raise concerns about the elderly population, which is probably the most important risk group for candiduria in the present moment, and the emergence of unusual yeast species producing candiduria, which are resistant against the commonly used antifungal agents.

Prevalence and distribution of hepatitis C virus genotypes in Spain during the 2000-2015 period (the GEHEP 005 study)

We report the largest study on the prevalence and distribution of HCV genotypes in Spain (2000-2015), and we relate them with clinical, epidemiological and virological factors. Patients from 29 hospitals in 10 autonomous communities (Andalusia, Aragon, Castilla-Leon, Catalonia, Galicia, Canary Islands, Madrid Community, Valencian Community, Murcia Region and Basque Country) have been studied. Annual distribution of HCV genotypes and subtypes, as well as gender, age, transmission route, HIV and/or HBV coinfection, and treatment details were recorded. We included 48595 chronically HCV-infected patients with the following characteristics: median age 51 years (IQR, 44-58), 67.9% male, 19.1% HIV-coinfected, 23.5% HBV-coinfected. Parenteral transmission route was the most frequent (58.7%). Genotype distribution was 66.9% GT1 (24.9% subtype 1a and 37.9% subtype 1b), 2.8% GT2, 17.3% GT3, 11.4% GT4 and 0.1% GT5 and 0.02% GT6. LiPA was the most widely HCV genotyping test used (52.4%). HCV subtype 1a and genotypes 3 and 4 were closely associated with male gender, parenteral route of infection and HIV and HBV coinfection; in contrast, subtype 1b and genotype 2 were associated with female gender, nonparenteral route and mono-infection. Age was related to genotype distribution, and different patterns of distribution and biodiversity index were observed between different geographical areas. Finally, we describe how treatment and changes in transmission routes may have affected HCV genotype prevalence and distribution patterns. We present the most recent data on molecular epidemiology of hepatitis C virus in Spain. This study confirms that genotype distributions vary with age, sex, HIV and HBV coinfection and within geographical areas and epidemiological groups.

HTLV infection in HCV-antibody positive patients in Spain

Since hepatitis C virus (HCV) and human T-lymphotropic virus (HTLV) share transmission routes, dual infection could be frequent. In Spain, HTLV underdiagnosis is highlighted by the high proportion of patients presenting either with tropical spastic paraparesis (TSP) or adult T-cell leukemia (ATL) at first diagnosis. We examined whether the renewed efforts for expanding HCV testing may provide a sentinel population that might selectively be targeted to unveil asymptomatic HTLV carriers. The presence of anti-HTLV antibodies was examined in 3,838 consecutive individuals with reactive HCV serology attended during the last three years at 13 hospitals distributed across the Spanish geography. Overall 71% were male and the median age was 41-years old. Foreigners represented 9% of the study population. A total of 50 individuals (1.3%) were seroreactive for HTLV, being 30 confirmed as HTLV-2 and two as HTLV-1 (0.12%). The remaining 18 had indeterminate Western blot patterns. Most individuals with HTLV-2 and HTLV indeterminate serology were HIV-positive, former injection drug users and native Spaniards. In contrast, the two HTLV-1 infections were found in men coming from Brazil and the Dominican Republic, respectively. In summary, the overall prevalence of HTLV infection in individuals living in Spain seropositive for HCV is 1.3%, more than 10-fold greater than in general outclinics in Spain. However, immigrants from HTLV-1 endemic regions and former injection drug users with HTLV-2 infection are by far the major contributory groups in HCV patients. Therefore, testing for HTLV in newly diagnosed HCV individuals would not contribute much to improve late HTLV diagnosis in Spain.

First Report of Acute Postoperative Endophthalmitis Caused by Rothia Mucilaginosa after Phacoemulsification

We aimed at reporting the first case of rapidly progressive acute postoperative endophthalmitis after phacoemulsification cataract surgery in an immunocompetent patient caused by Rothia mucilaginosa. An immunocompetent patient manifested endophthalmitis signs 48 hours after an uncomplicated cataract surgery by phacoemulsification. A bacteria of the family Micrococcaceae was cultured in the vitreous biopsy, namely R. mucilaginosa. The patient did not show a favorable clinical response after vitrectomy and systemic, intravitreal, and topical fortified antibiotics. The patient’s eye was very painful, and consequently, it deemed necessary to perform an evisceration. R. mucilaginosa may be an aggressive etiologic agent for postoperative endophthalmitis. Although the isolated R. mucilaginosa was susceptible to empirical treatment, it was impossible to control the infection with standard treatment, probably due to its ability to create a biofilm around the intraocular lens.

Candida nivariensis as a New Emergent Agent of Vulvovaginal Candidiasis: Description of Cases and Review of Published Studies

Candida nivariensis is a new emergent agent related to human infections in the vaginal tract and other localizations, but the phenotypic characteristics are very similar to Candida glabrata and can be misidentified and underdiagnosed. We described four cases of vulvovaginitis identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and confirmed the results with PCR amplification and sequencing of the entire ITS genomic region (ITS1, ITS2 and 5.8 rRNA). We reinforce the need for new diagnostic tools for the correct identification of yeast infections.

Description of the OXA-23 β-lactamase gene located within Tn2007 in a clinical isolate of Acinetobacter baumannii from Spain

A carbapenem-resistant Acinetobacter baumannii expressing blaOXA-23 was recovered from an intensive care unit patient in a third-level hospital from Spain. Genetic analysis showed the association of this carbapenemase with the transposon Tn2007 located in a plasmid of 10 kb. The isolate was classified as ST-1. This strain has shown a potential ability to displace other endemic strains in the hospital and is the first reported identification of A. baumannii carrying blaOXA-23 related to Tn2007 in Spain.

[Infections due to Mycobacterium simiae]

Mycobacterium simiae is a slow-growing photochromogenic environmental mycobacterium, first described in 1965. Rarely associated with human infections, possibly due to its limited pathogenicity, it mainly produces lung infection in immunocompetent elderly patients with underlying lung disease, and in disseminated infections in immunosuppressed young patients with AIDS. A microbiological culture is needed to confirm the clinical suspicion, and genetic sequencing techniques are essential to correctly identify the species. Treating M. simiae infections is complicated, owing to the multiple resistance to tuberculous drugs and the lack of correlation between in vitro susceptibility data and in vivo response. Proper treatment is yet to be defined, but must include clarithromycin combined with other antimicrobials such as moxifloxacin and cotrimoxazole. It is possible that M. simiae infections are undiagnosed.

Molecular epidemiology and clinical features of human T cell lymphotropic virus type 1 infection in Spain

Human T cell lymphotropic virus type 1 (HTLV-1) infection in Spain is rare and mainly affects immigrants from endemic regions and native Spaniards with a prior history of sexual intercourse with persons from endemic countries. Herein, we report the main clinical and virological features of cases reported in Spain. All individuals with HTLV-1 infection recorded at the national registry since 1989 were examined. Phylogenetic analysis was performed based on the long terminal repeat (LTR) region. A total of 229 HTLV-1 cases had been reported up to December 2012. The mean age was 41 years old and 61% were female. Their country of origin was Latin America in 59%, Africa in 15%, and Spain in 20%. Transmission had occurred following sexual contact in 41%, parenteral exposure in 12%, and vertically in 9%. HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) was diagnosed in 27 cases and adult T cell leukemia/lymphoma (ATLL) in 17 subjects. HTLV-1 subtype could be obtained for 45 patients; all but one belonged to the Cosmopolitan subtype a. One Nigerian pregnant woman harbored HTLV-1 subtype b. Within the Cosmopolitan subtype a, two individuals (from Bolivia and Peru, respectively) belonged to the Japanese subgroup B, another two (from Senegal and Mauritania) to the North African subgroup D, and 39 to the Transcontinental subgroup A. Of note, one divergent HTLV-1 strain from an Ethiopian branched off from all five known Cosmopolitan subtype 1a subgroups. Divergent HTLV-1 strains have been introduced and currently circulate in Spain. The relatively large proportion of symptomatic cases (19%) suggests that HTLV-1 infection is underdiagnosed in Spain.

[Viral infections]

Los virus pueden causar enfermedad, tras superar las barreras protectoras naturales del organismo y evadir el control inmunológico, destruyendo células o desencadenando una respuesta inflamatoria e inmunitaria que puede causar daño al propio organismo. El desarrollo de la infección vírica está determinado por el tipo de relación virus/hospedador y la respuesta de este a la infección. Las infecciones víricas pueden ser líticas o persistentes (latencia, recurrencia y/o transformación de la célula). La respuesta inmunitaria es la mejor herramienta para controlar la diseminación del virus; sin embargo, en ocasiones, contribuye a la patogénesis de la infección. El laboratorio aporta información relevante mediante la descripción del efecto citopático inducido por el virus, la detección de las partículas víricas utilizando microscopía electrónica, el aislamiento y crecimiento del virus en medios celulares in vitro, la detección de componentes víricos (proteínas y ácidos nucleicos) y la evaluación de la respuesta inmunitaria del paciente frente al virus.

[Antifungal susceptibility of clinical isolates of Scopulariopsis species]

INTRODUCTION

Scopulariopsis is a common soil saprophyte. In the last years the infections caused by Scopulariopsis species have increased, included superficial and invasive mycoses. This fungi has been reported resistant in vitro to some antifungal agents, although there is little information about this. The aim of the study was to establish in vitro antifungal susceptibility of clinical isolates of Scopulariopsis species against to broad-spectrum antifungal agents.

METHODS

A total of 28 Scopulariopsis strains (10 S. brevicaulis, 7 S. koningii, 3 S. acremonium, 3 S. candida, 3 S. flava, 1 S. brumptii and 1 S. fusca) were tested using Sensititre Yeast One and broth microdilution methods to determine the minimum inhibitory concentrations (MICs) to amphotericin B, fluconazole, itraconazole, posaconazole, voriconazole and 5-fluorocytosine, and minimun effective concentration (MECs) to anidulafungin, caspofungin and micafungin.

RESULTS

Our data confirm the high in vitro resistance of Scopulariopsis to antifungal agents. Anidulafungin, caspofungin, micafungin (MICs ≥ 8 mg/L), 5-fluorocytosine (MICs ≥ 64 mg/L), and fluconazole (MICs ≥ 128 mg/L) were inactive in vitro in all species. MICs of amphotericin B (range 2 to ≥ 8 mg/L) and itraconazole (0.5 to ≥ 16 mg/L) were high. The best antifungal activity was observed for posaconazole and voriconazole (0.5 to ≥ 8 mg/L). With Sensititre Yeast One method MICs obtained slightly lower. Scopulariopsis candida, S. flava and S. fusca were the most resistant species, while S. acremonium and S. brevicaulis showed the lowest MICs.

CONCLUSIONS

MICs of all tested antifungal agents for Scopulariopsis were very high. Infections caused by Scopulariopsis species may not respond to antifungal treatment. Voriconazole is the drug of choice for treatment. We consider it appropriate to add amphotericin B in serious infections.

[Diagnosis of vaginitis-vaginosis by hibridization with DNA strands]

BACKGROUND

Vaginal infections lie among the most common causes women ask for medical advice. In order of frequency bacterial vaginosis, vulvovaginal candidiasis, and trichomoniasis are responsible for 90% of vaginitis/vaginosis.

OBJECTIVE

To evaluate a DNA hybridization test for simultaneous molecular detection of Gardnerella vaginalis, Candida species and Trichomonas vaginalis, as an alternative to conventional microbiological methods.

MATERIAL AND METHODS

Cohort, cross-sectional, and comparative study of 1,003 vaginal samples from symptomatic women from our health-care area. Two swabs were obtained from each woman, one for routine microbiological diagnosis of vaginal infection (wet mount, Gram stain, and mycological culture) and the other for the DNA hybridization test (Affirm VPIII, Becton Dickinson). This method detects clinically significant levels of G. vaginalis (2 x 10(5) CFU/ml), Candida spp. (1 x 10(4) cells) and T. vaginalis (5x103 trichomonads).

RESULTS

Out of the 1,003 women studied, 30.6% tested positive for bacterial vaginosis, 23.3% for vulvovaginal candidiasis, and 0.5% for trichomoniasis. The Affirm VPIII method turned out positive in 27.5%, 27.4% and 0.5% of cases, respectively. No statistically significant differences were found between the molecular technique and conventional methods for microbiological diagnosis of vaginitis/ vaginosis (p < 0.05).

CONCLUSION

The Affirm VPIII test correlated well with wet mount, Gram stain and mycological culture. Although its cost is relatively high, it is fast, reproducible, easy, and can be done in either clinical laboratories or Gynecology offices, which permits prescribing a specific early treatment.

Viral infections of the central nervous system in Spain: a prospective study

The aim of the study was to determine the incidence of viruses causing aseptic meningitis, meningoencephalitis, and encephalitis in Spain. This was a prospective study, in collaboration with 17 Spanish hospitals, including 581 cases (CSF from all and sera from 280): meningitis (340), meningoencephalitis (91), encephalitis (76), febrile syndrome (7), other neurological disorders (32), and 35 cases without clinical information. CSF were assayed by PCR for enterovirus (EV), herpesvirus (herpes simplex [HSV], varicella-zoster [VZV], cytomegalovirus [CMV], Epstein-Barr [EBV], and human herpes virus-6 [HHV-6]), mumps (MV), Toscana virus (TOSV), adenovirus (HAdV), lymphocytic choriomeningitis virus (LCMV), West Nile virus (WNV), and rabies. Serology was undertaken when methodology was available. Amongst meningitis cases, 57.1% were characterized; EV was the most frequent (76.8%), followed by VZV (10.3%) and HSV (3.1%; HSV-1: 1.6%; HSV-2: 1.0%, HSV non-typed: 0.5%). Cases due to CMV, EBV, HHV-6, MV, TOSV, HAdV, and LCMV were also detected. For meningoencephalitis, 40.7% of cases were diagnosed, HSV-1 (43.2%) and VZV (27.0%) being the most frequent agents, while cases associated with HSV-2, EV, CMV, MV, and LCMV were also detected. For encephalitis, 27.6% of cases were caused by HSV-1 (71.4%), VZV (19.1%), or EV (9.5%). Other positive neurological syndromes included cerebellitis (EV and HAdV), seizures (HSV), demyelinating disease (HSV-1 and HHV-6), myelopathy (VZV), and polyradiculoneuritis (HSV). No rabies or WNV cases were identified. EVs are the most frequent cause of meningitis, as is HSV for meningoencephalitis and encephalitis. A significant number of cases (42.9% meningitis, 59.3% meningoencephalitis, 72.4% encephalitis) still have no etiological diagnosis.

Evaluation of the Sensititre Yeast One microdilution method for susceptibility testing of Candida species to anidulafungin, caspofungin, and micafungin

INTRODUCTION

Echinocandins represent a new antifungal group with potent activity against Candida species. The purpose of our study was to evaluate the utility of the Sensititre Yeast One method to determine the in vitro activity of anidulafungin, micafungin, and caspofungin against Candida species isolated from clinical specimens.

METHODS

A total of 131 Candida strains were tested using Sensititre Yeast One colorimetric microdilution method. They belonged to the following species: 42 C. albicans, 36 C. glabrata, 21 C. parapsilosis, 12 C. tropicalis, 10 C. krusei, 3 C. guilliermondii, 2 C. famata, 3 C. kefyr, 1 C. lusitaniae, 1 C. zeylanoides, and 1 C. lipolytica. For being considered susceptible the strains had to be inhibited by concentrations ≤2 mg/L of anidulafungin, caspofungin or micafungin.

RESULTS

The 80.1% of the strains tested were inhibited by concentrations ≤0.25 mg/L of anidulafungin and micafungin. The activity of caspofungin was slightly lower (78.6% of strains inhibited by concentrations ≤0.25 mg/L). The 96.9% of strains turned out susceptible to concentrations ≤2 mg/L against the three echinocandins. Two strains of C. parapsilosis (9.5%), one of C. guilliermondii, and two of C. famata showed non-susceptible to one or more echinocandins.

CONCLUSIONS

In our series, anidulafungin, micafungin, and caspofungin were effective against C. albicans, C. glabrata, C. tropicalis, C. krusei, C. kefyr, C. lusitaniae and C. lipolytica. The 96.9% of strains were susceptible to all three echinocandins. Thus, echinocandins are proved to exhibit excellent activity to the Candida species most frequently involved in human infections, except Candida parapsilosis.

[Susceptibility to fluconazole of clinical interest yeasts: new breakpoints]

INTRODUCTION

Recently, Pfaller et al (Drug Resist Update 2010; 13:180-95), have proposed new breakpoints for determining the in vitro susceptibility to fluconazole of Candida albicans, C. parapsilosis and C. tropicalis. The aim of this study was to establish the variations in sensitivity of these species applying these breakpoints, in relation to those of the Clinical and Laboratory Standards Institute (CLSI).

METHODS

We analyzed 112 strains of Candida: 49 C. albicans, 40 C. parapsilosis and 23 C. tropicalis. Susceptibility to fluconazole was performed by the method Sensititre YeastOne. The breakpoints used to determine the minimum inhibitory concentration (MIC) were identified by CLSI and the ones proposed by Pfaller et al.

RESULTS

According to the CLSI criteria, all isolates were susceptible to fluconazole. MIC50 and MIC90 were 0.5 mg/L and 2 mg/L for C. albicans and C. parapsilosis, 0.5 mg/L and 1 mg/L for C. tropicalis. With the new criteria, 109 (97%) strains were susceptible. Variations were seen in C. albicans, with 3 strains (6%) susceptible dose-dependent.

CONCLUSIONS

When applying the breakpoints recommended by Pfaller et al, and EUCAST, the number of fluconazole-susceptible strains decreased according to the CLSI criteria, especially C. albicans.

Evaluation of INNO-LiPA mycobacteria v2 assay for identification of rapidly growing mycobacteria

A total of 54 rapidly growing mycobacteria (RGM) isolated from patients attended in the two hospitals of Cádiz Bay (Spain) were selected during a seven-year-period (2000–2006) in order to evaluate the INNO-LiPA Mycobacteria v2 assay for mycobacterial identification, based on the reverse hybridization principle. The strains were cultured in Löwenstein-Jensen and Middlebrook 7H9 media and identified to the species level by sequencing of the 16S rRNA, PCR-restriction enzyme analysis of the hsp65 gene, conventional tests and INNO-LiPA Mycobacteria v2 assay. By the molecular methods we identified a total of 12 different species: 23 Mycobacterium fortuitum, 11 M. chelonae, 10 M. abscessus, 2 M. senegalense, 1 M. alvei, 1 M. brumae, 1 M. mageritense, 1 M. mucogenicum, 1 M. neoaurum, 1 M. peregrinum, 1 M. septicum and 1 M. smegmatis. Fifty two strains (96.3%) were correctly identified by conventional techniques and 47 strains (87.0%) by INNO-LiPA Mycobacteria v2 assay. We find INNO-LiPA Mycobacteria v2 assay simple to perform but it provides few advantages in comparison with conventional methods and sometimes needs complementary tests to identify Mycobacterium fortuitum complex, M. chelonae complex and specific species due to the great heterogeneity in the RGM group.

[Rapid identification of Mycobacterium tuberculosis complex from broth cultures by immunochromatographic assay]

BACKGROUND

Recently, a simple and rapid commercial assay (BD MGIT TBc ID) has been developed using a monoclonal antibody anti-MPT64 for the differentiation of Mycobacterium tuberculosis complex from other mycobacteria by immunochromatography.

METHODS

We evaluate in this work the clinical usefulness of the test for the identification of 51 strains of M. tuberculosis complex and 24 strains of other mycobacteria belonging to 14 different species, compared with the method of hybridization with DNA probes.

RESULTS

Immunochromatographic method performance was excellent, with sensitivity, specificity, positive and negative predictive values of 98, 100, 96.1, and 98.7%, respectively.

CONCLUSIONS

These results indicate that immunochromatographic assay can be safely used for rapid identification of M. tuberculosis complex in combination with culture in liquid media. The test is extremely simple, provides results in just 15 minutes, requires no complex equipment or specialized personnel and may be a good alternative to molecular methods, especially in small laboratories.

Prevalence of HTLV-1/2 infections in Spain: A cross-sectional hospital-based survey

The presence of antibodies to human T-lymphotropic virus (HTLV) types 1 and 2 was examined in 5742 sera belonging to consecutive adult outpatients attended during June 2008 at 13 different hospitals across Spain. Overall, 58.8% were female. Foreigners represented 8% of the study population. Seven individuals were seropositive for HTLV-2 (overall prevalence 0.12%). No cases of HTLV-1 infection were found. All HTLV-2(+) subjects were Spanish natives, of whom six were coinfected with HIV-1 and five with hepatitis C virus (HCV). Moreover, all but one of the HTLV-2(+) subjects had been intravenous drug users. In summary, this cross-sectional survey suggests that the rate of HTLV infection in Spain is low, and is mostly represented by HTLV-2. Infected individuals are generally Spanish natives with a prior history of intravenous drug use and are coinfected with HIV-1 and/or HCV.

Seroprevalence of HTLV-1/2 infection among native and immigrant pregnant women in Spain

HTLV-1=2 antenatal screening is not mandatory in European countries. The rapid increase in immigrants coming from areas endemic for HTLV-1 infection has compelled a review of this policy in Spain. From February 2006 to December 2007, a cross-sectional study was carried out in all pregnant women attended at 10 different Spanish hospitals. An enzyme immunoassay (EIA) was used to test serum HTLV-1=2 antibodies; reactive samples were further confirmed by Western blot and=or polymerase chain reaction. A total of 20,518 pregnant women were examined, of whom 18,266 (89%) were native Spaniards. Overall, 946 (4.6%) of the immigrants came from HTLV-1 endemic areas (mainly Central and South America and sub-Saharan Africa). Four samples were EIA seroreactive for HTLV-1=2, two of them in women infected with HTLV-1 coming from endemic areas. The other two women were infected with HTLV-2; one was an immigrant from Bolivia and another was a native Spaniard who admitted prior injection drug use and was HIV-1 positive. The overall HTLV-1=2 seroprevalence was 0.19 per 1000 (95% CI: 0.05-0.49=1000). For HTLV-1, the seroprevalence was 2.11 per 1000 (95% CI: 0.26-7.62=1000) in pregnant women from endemic areas. The seroprevalence of HTLV-1=2 infection is below 0.02% among pregnant women in Spain, and therefore universal screening for HTLV-1=2 infection in antenatal clinics is not warranted. However, HTLV-1=2 screening could be considered in pregnant women coming from endemic areas, in whom the rate of infection is nearly 1000-fold higher than in native Spaniards and are the only group infected with the more pathogenic HTLV-1.