Oral saliva swab reverse transcription PCR for Covid-19 in the paediatric population.

OBJECTIVES: To evaluate the performance of oral saliva swab (OSS) reverse transcription PCR (RT-PCR) compared with RT-PCR and antigen rapid diagnostic test (Ag-RDT) on nasopharyngeal swabs (NPS) for SARS-CoV-2 in children. DESIGN: Cross-sectional multicentre diagnostic study. SETTING: Study nested in a prospective, observational cohort (EPICO-AEP) performed between February and March 2021 including 10 hospitals in Spain. PATIENTS: Children from 0 to 18 years with symptoms compatible with Covid-19 of ≤5 days of duration were included. Two NPS samples (Ag-RDT and RT-PCR) and one OSS sample for RT-PCR were collected. MAIN OUTCOME: Performance of Ag-RDT and RT-PCR on NPS and RT-PCR on OSS sample for SARS-CoV-2. RESULTS: 1174 children were included, aged 3.8 years (IQR 1.7-9.0); 73/1174 (6.2%) patients tested positive by at least one of the techniques. Sensitivity and specificity of OSS RT-PCR were 72.1% (95% CI 59.7 to 81.9) and 99.6% (95% CI 99 to 99.9), respectively, versus 61.8% (95% CI 49.1 to 73) and 99.9% (95% CI 99.4 to 100) for the Ag-RDT. Kappa index was 0.79 (95% CI 0.72 to 0.88) for OSS RT-PCR and 0.74 (95% CI 0.65 to 0.84) for Ag-RDT versus NPS RT-PCR. CONCLUSIONS: RT-PCR on the OSS sample is an accurate option for SARS-CoV-2 testing in children. A less intrusive technique for younger patients, who usually are tested frequently, might increase the number of patients tested.

Vaccine breakthrough infections with SARS-CoV-2 Alpha mirror mutations in Delta Plus, Iota, and Omicron.

Replication of SARS-CoV-2 in the human population is defined by distributions of mutants that are present at different frequencies within the infected host and can be detected by ultra-deep sequencing techniques. In this study, we examined the SARS-CoV-2 mutant spectra of amplicons from the spike-coding (S-coding) region of 5 nasopharyngeal isolates derived from patients with vaccine breakthrough. Interestingly, all patients became infected with the Alpha variant, but amino acid substitutions that correspond to the Delta Plus, Iota, and Omicron variants were present in the mutant spectra of the resident virus. Deep sequencing analysis of SARS-CoV-2 from patients with vaccine breakthrough revealed a rich reservoir of mutant types and may also identify tolerated substitutions that can be represented in epidemiologically dominant variants.

Historical evolution of the diseases caused by non-pigmented rapidly growing mycobacteria in a University Hospital / Evolución histórica de las enfermedades causadas por micobacterias no pigmentadas de crecimiento rápido en un Hospital Universitario

INTRODUCTION: Non-pigmented rapidly growing mycobacteria (NPRGM) are a group of organisms of increasing interest due to the growing number of potential patients and the difficulties for a proper treatment in many of them. However, the evolution of these diseases in a long period of time and its evolutionary changes has been described only in a scanty number of reports. MATERIAL AND METHODS: We performed a retrospective study between January 1st 2004 and December 31st 2017 in order to evaluate the clinical significance and types of diseases caused by NPRGM. Patients with isolates of NPRGM during this period were selected for the study, and clinical charts were reviewed using a predefined protocol. RESULTS: During this period we identified 59 patients (76 clinical samples) with isolates of NPRGM, with 12 cases of clinical disease and one patient with doubtful significance (including 6 respiratory tract infections, 2 catheter infections, 1 skin and soft tissue infection, 1 disseminated infection, 1 conjunctivitis, 1 prosthetic joint infection and 1 mastitis). Fifty percent of M. chelonae isolates, 37.5% of M. abscessus isolates and 23.33% of M. fortuitum isolates were clinically significant. None of the isolates of other species were significant. CONCLUSIONS: Most isolates in respiratory samples were contaminants/colonizations. M. abscessus was the main etiological agent in respiratory syndromes, whereas M. chelonae and M. fortuitum were more frequently associated with other infections, especially clinical devices and skin and soft tissue infections

INTRODUCCIÓN: Las micobacterias no pigmentadas de crecimiento rápido (MNPCR) son un grupo de organismos de interés creciente debido al número cada vez mayor de pacientes potenciales y a las dificultades en el tratamiento. Sin embargo, el número de estudios que analizan la evolución de estos casos a lo largo de un periodo de tiempo largo es escaso. MATERIAL Y MÉTODOS: Se realizó un estudio retrospectivo entre el 1 de enero de 2004 y el 31 de diciembre de 2017 para evaluar el significado clínico y los tipos de enfermedades causados por MNPCR. Se seleccionaron para ello aquellos pacientes con aislamientos de MNPCR, y se revisaron las historias clínicas mediante un protocolo predefinido. RESULTADOS: Se identificaron 59 pacientes (76 muestras) con aislamientos de MNPCR, de los cuales 12 presentaron enfermedad y uno tuvo un significado dudoso (incluyendo 6 infecciones respiratorias, 2 infecciones asociadas a catéter, 1 infección de piel y partes blandas, 1 infección diseminada, 1 conjuntivitis, 1 infección de prótesis osteoarticular y 1 mastitis). El 50 % de los aislamientos de Mycobacterium chelonae, el 37,5 % de Mycobacterium abscessus y el 23,33 % de Mycobacterium fortuitum fueron clínicamente significativos. Ninguno de los aislamientos de otras especies fue significativo. CONCLUSIONES: La mayoría de los aislamientos de muestras respiratorias resultaron ser contaminantes/colonizaciones. M. abscessus fue el principal agente etiológico en las infecciones respiratorias, mientras que M. chelonae y M. fortuitum fueron asociados con mayor frecuencia a otras infecciones, especialmente infecciones de piel y partes blandas e infecciones asociadas a dispositivos biomédicos

Antimicrobial Treatment Provides a Competitive Advantage to Mycobacterium abscessus in a Dual-Species Biofilm with Pseudomonas aeruginosa.

The physiological factors that contribute to Mycobacterium abscessus lung infections remain unclear. We determined whether antibiotic treatment targeting a major cystic fibrosis pathogen (i.e., Pseudomonas aeruginosa) could provide the ideal conditions for the establishment of M. abscessus infection. Our data showed that P. aeruginosa inhibited M. abscessus biofilm formation under control conditions and that antimicrobial therapy selectively targeting P. aeruginosa diminished this competitive interaction, thereby increasing M. abscessus survival.

The "Race for the Surface" experimentally studied: In vitro assessment of Staphylococcus spp. adhesion and preosteoblastic cells integration to doped Ti-6Al-4V alloys.

OBJECTIVE: Implant-related infection is a devastating complication in orthopedic surgery. Aiming to minimize this problem, many material modifications have been developed. Here we report a study of a surface modification of Ti-6 Al-4 V alloy using a methodology that enables the study of interactions between bacteria and the material in the presence of eukaryotic cells. METHODS: We mixed different concentrations of collection or clinical strains of staphylococci isolated from implant-related infections with preosteoblastic cells using a previously published methodology, analyzing the minimal concentration of bacteria able to colonize the surface of the material through image analysis. Ti-6 Al-4 V alloy was modified by anodization to obtain two F-doped nanostructured surfaces that have been previously described to have antibacterial properties. RESULTS: Our results show similar bacterial adhesion results to nanoporous and nanotubular F-doped surfaces. The presence of preosteoblastic cells increases the adherence of all bacterial strains to both structures. No effect of the surface on eukaryotic cells adherence was detected. CONCLUSION: To our knowledge, this is the first time that anin vitro study emulating the race for the surface evaluates and compares the osseointegration and antibacterial properties between two nanostructured- modified titanium alloy surfaces. Clinical strains show different behavior from collection ones in bacterial adherence. The presence of cells increased bacterial adherence. NP and NT surface modifications didn´t show significant differences in bacterial adhesion and preosteoblastic cells integration.

Non-Tuberculous Mycobacteria multispecies biofilms in cystic fibrosis: development of an in vitro Mycobacterium abscessus and Pseudomonas aeruginosa dual species biofilm model.

Lung disease in cystic fibrosis (CF) is characterized by the progressive colonization of the respiratory tract by different bacteria, which develop polymicrobial biofilms. In the past decades, there has been an increase in the number of CF patients infected with Non-Tuberculous Mycobacteria (NTM). Although Mycobacterium abscessus is the main NTM isolated globally, little is known about M. abscessus multispecies biofilm formation. In the present study we developed an in vitro model to study the phenotypic characteristics of biofilms formed by M. abscessus and Pseudomonas aeruginosa, a major pathogen in CF. For that purpose, dual species biofilms were grown on polycarbonate membranes with a fixed concentration of P. aeruginosa and different inoculums of M. abscessus. The biofilms were sampled at 24, 48, and 72 h and bacteria were quantified in specific media. The results revealed that the increasing initial concentration of M. abscessus in dual species biofilms had an effect on its population only at 24 and 48 h, whereas P. aeruginosa was not affected by the different concentrations used of M. abscessus. Time elapsed increased biofilm formation of both species, specially between 24 and 48 h. According to the results, the conditions to produce a mature dual species biofilm in which the relative species distribution remained stable were 72 h growth of the mixed microbial culture at a 1:1 ratio. A significant decrease in mycobacterial population in dual compared to single species biofilms was found, suggesting that P. aeruginosa has a negative influence on M. abscessus. Finally, in a proof of concept experiment, young and mature dual species biofilms were exposed to clarithromycin.

Evaluation of a commercial multiplex PCR (Unyvero i60(R)) designed for the diagnosis of bone and joint infections using prosthetic-joint sonication / Evaluación de una PCR múltiple comercial (Unyvero i60(C)) diseñada para el diagnóstico de infecciones osteoarticulares utilizando prótesis articulares sonicadas

BACKGROUND: The development of sonication protocols over the last few years has improved the sensitivity of conventional cultures for the diagnosis of prosthetic-joint infection (PJI). However, the development of a new, specifically designed kit for the molecular diagnosis of PJI could provide a major improvement in this field. METHODS: Prostheses retrieved from patients who underwent implant removal from May 2014 to May 2015 were sent for culture, and processed according to a previously defined protocol that included sonication. Furthermore, 180 microlitres of sonication fluid were used to carry out the multiplex PCR test (Unyvero i60 system®). A comparison of the sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, was performed. The study was approved by the Clinical Research Ethics Committee. RESULTS: The analysis included 88 prostheses from 68 patients (1.29 prostheses/patient). The type of prostheses studied were knee (n=55), total hip (n=26), partial hip (n=5), and shoulder (n=2). Twenty-nine patients were diagnosed with a PJI (15 delayed, 12 acute, and 2 haematogenous infections). In 24 cases, the result of the PCR was positive, all but 1 corresponding to patients with clinical criteria of PJI. Nine resistance mechanisms were detected from 5 samples. The Unyvero i60 system® showed slightly better results than traditional culture in terms of specificity and PPV. CONCLUSIONS: The Unyvero i60 system® may play a role in rapid diagnosis of PJI, due to its high specificity and PPV. However, despite these results, cultures have to be performed to detect organisms not detected by the system

INTRODUCCIÓN: El desarrollo de la sonicación durante los pasados años ha incrementado la sensibilidad de los cultivos convencionales para el diagnóstico de Infecciones de Prótesis Articulares (IPA). Sin embargo, el desarrollo de un nuevo kit, diseñado específicamente para el diagnóstico de las IPA podría suponer un avance significativo en este campo. MÉTODOS: Todas las prótesis retiradas de pacientes entre mayo 2014 y mayo 2015 fueron enviadas para cultivo mediante un protocolo de procesamiento que incluye la sonicación del implante. Además, se emplearon 180 microlitros del líquido de sonicado en la realización de una PCR múltiple (Unyvero i60®). Se realizó una comparación de la sensibilidad, especificidad, valor predictivo positivo (VPP) y negativo (VPN). El estudio fue aprobado por el Comité de Ética en Investigación Clínica. RESULTADOS: Se analizaron 88 prótesis de 68 pacientes (1,29 prótesis/paciente). Las prótesis estudiadas fueron rodillas (n=55), total de cadera (n=26), parcial de cadera (n=5), y hombro (n=2). Veintinueve pacientes fueron diagnosticados de IPA (15 crónicas, 12 agudas y 2 hematógenas). En 24 casos, el resultado de la PCR fue positivo, siendo todas menos 1 de estas de pacientes con criterios de IPA. Se detectaron además 9 mecanismos de resistencia en 5 muestras. El sistema Unyvero i60® mostró resultados ligeramente superiores al cultivo tanto en especificidad como en VPP. CONCLUSIONES: El sistema Unyvero i60® puede tener un papel en el diagnóstico rápido de IPA debido a su elevada especificidad y VPP. Sin embargo, a pesar de estos resultados, debe realizarse cultivo para detectar organismos no detectados por el sistema

Bacterial and fungal biofilm formation on anodized titanium alloys with fluorine.

Orthopaedic device-related infections are closely linked to biofilm formation on the surfaces of these devices. Several modified titanium (Ti-6Al-4V) surfaces doped with fluorine were studied in order to evaluate the influence of these modifications on biofilm formation by Gram-positive and Gram-negative bacteria as well as a yeast. The biofilm studies were performed according to the standard test method approved by ASTM (Designation: E2196-12) using the Rotating Disk Reactor. Four types of Ti-6Al-4V samples were tested; chemically polished (CP), two types of nanostructures containing fluorine, nanoporous (NP) and nanotubular (NT), and non-nanostructured fluorine containing samples (fluoride barrier layers, FBL). Different species of Gram-positive cocci, (Staphylococcus aureus and epidermidis), Gram-negative rods (Escherichia coli, Pseudomonas aeruginosa), and a yeast (Candida albicans) were studied. For one of the Gram-positive (S. epidermidis) and one of the Gram-negative (E. coli) species a statistically-significant decrease in biofilm accumulation for NP and NT samples was found when compared with the biofilm accumulation on CP samples. The results suggest an effect of the modified materials on the biofilm formation.

Evaluation of a commercial multiplex PCR (Unyvero i60®) designed for the diagnosis of bone and joint infections using prosthetic-joint sonication.

BACKGROUND: The development of sonication protocols over the last few years has improved the sensitivity of conventional cultures for the diagnosis of prosthetic-joint infection (PJI). However, the development of a new, specifically designed kit for the molecular diagnosis of PJI could provide a major improvement in this field. METHODS: Prostheses retrieved from patients who underwent implant removal from May 2014 to May 2015 were sent for culture, and processed according to a previously defined protocol that included sonication. Furthermore, 180 microlitres of sonication fluid were used to carry out the multiplex PCR test (Unyvero i60 system®). A comparison of the sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, was performed. The study was approved by the Clinical Research Ethics Committee. RESULTS: The analysis included 88 prostheses from 68 patients (1.29 prostheses/patient). The type of prostheses studied were knee (n=55), total hip (n=26), partial hip (n=5), and shoulder (n=2). Twenty-nine patients were diagnosed with a PJI (15 delayed, 12 acute, and 2 haematogenous infections). In 24 cases, the result of the PCR was positive, all but 1 corresponding to patients with clinical criteria of PJI. Nine resistance mechanisms were detected from 5 samples. The Unyvero i60 system® showed slightly better results than traditional culture in terms of specificity and PPV. CONCLUSIONS: The Unyvero i60 system® may play a role in rapid diagnosis of PJI, due to its high specificity and PPV. However, despite these results, cultures have to be performed to detect organisms not detected by the system.

Antibacterial effect of antibiotic-loaded SBA-15 on biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis.

Staphylococcus aureus and Staphylococcus epidermidis are human pathogens involved in implant-related infections. During those diseases, they are able to form biofilms showing resistance to the effect of many different antibiotics. Drug delivery systems allow a local and effective delivery of antibiotics at high concentrations in the infected tissue without causing the cytotoxic effects commonly linked to systemic administration. We report the use of a porous ceramic biomaterial, such as SBA-15 loaded with antibiotics, to deliver them directly to the infected tissue. SBA-15 discs were loaded with Vancomycin, Rifampin and a combination of both, introduced in a suspension of S. aureus 15981 and S. epidermidis ATCC 35984 and incubated during 6 and 24 h. A statistically significant decrease in the biofilm density and the number of viable bacteria was detected for all antibiotics at 6 h in both bacteria. Rifampin showed an increase in the biofilm density and the number of viable bacteria at 24 h. No differences were detected between Vancomycin and the combination of antibiotics. S. epidermidis was more sensitive to the effect of the antibiotics than S. aureus. Here we have demonstrated that SBA-15 is able to act as an effective drug delivery system not only from a pharmaceutical point of view, but also from a biological one.

Drug treatments for prosthetic joint infections in the era of multidrug resistance.

INTRODUCTION: Despite many advances, the management of prosthetic joint infection is still a complex issue. Moreover, in recent years the problem of antimicrobial resistance has emerged as an important challenge. AREAS COVERED: We analysed recent advances in different aspects of prosthetic joint infections. The importance of biofilms needs to be considered for antibiotic selection because, when embedded in these structures, bacteria acquire resistant behaviour. Moreover, the presence of resistance mechanisms in some species of organisms increases the difficulty of management. In this sense, the growing importance of methicillin-resistant staphylococci, multidrug-resistant Enterobacteriaceae or Pseudomonas aeruginosa is of increasing concern. Together with these organisms, others with constitutive resistance against most antibiotics (like Enterococcus sp., mycobacteria or fungi) represent a similar problem for selection of therapy. Research into new materials that can be used as drug carriers opens a new field for management of these infections and will likely come to the front line in the coming years. EXPERT OPINION: Individualised therapies should carefully consider the aetiology, pathogenesis and antimicrobial susceptibility. Satisfactory clinical outcome could be further fostered by enhancing the multidisciplinary approach, with better collaboration in the antibiotic selection and the surgical management.

Bacterial adhesion on biomedical surfaces covered by yttria stabilized zirconia.

The aim of this study was to compare the bacterial adhesion of Staphylococcus spp. on Ti-6Al-4V with respect to Ti-6Al-V modified alloys with a set of Cubic yttria stabilized zirconia (YSZ) and Ag-YSZ nanocomposite films. Silver is well known to have a natural biocidal character and its presence in the surface predicted to enhance the antimicrobial properties of biomedical surfaces. Microbial adhesion tests were performed using collection strains and twelve clinical strains of Staphylococcus aureus and Staphylococcus epidermidis. The adherence study was performed using a previously published protocol by Kinnari et al. Both collection strains and clinical isolates have shown lower bacterial adhesion to materials modified with respect to the alloy Ti-6Al-4V and the modification with silver reduced the bacterial adhesion for most of all the strains studied. Moreover the percentage of dead bacteria have been evaluated, demonstrating increased proportion of dead bacteria for the modified surfaces. Nanocrystalline silver dissolves releasing both Ag(+) and Ag(0) whereas other silver sources release only Ag(+). We can conclude that YSZ with nanocrystalline silver coating may lead to diminished postoperative infections and to increased corrosion and scratch resistance of YSZ incorporating alloys Ti-6Al-4V.

Use of anodized titanium alloy as drug carrier: Ibuprofen as model of drug releasing.

The use of osteoarticular implants has improved the quality of life of millions of patients. In this work nanotubular structures tailored made on Ti6Al4V substrates was used as drug delivery system of ibuprofen as a proof of concept. Three different nanotubular films with different sizes and forms (NT, NT+ and NTb) were analysed. Samples were soaked in a solution of 660 mg ibuprofen/20 mL n-pentane. The ibuprofen release in aqueous medium was evaluated by liquid chromatography reversed-phase (RP-HPLC). To calculate the observed constant k, the amount of ibuprofen released was plotted versus the time using linear regression according to the zero-order, first-order, second-order and Higuchi model. The release of ibuprofen was constant and independent of the concentration. The kinetic constant obtained was 0.021 (NT), 0.022 (NT+) and 0.013 (NTb) being the correlation factor of 0.98 (zero-order) where the maximum correlation factor was reached. These results indicate that the delivery process from NT and NT+ is similar and slower that NTb. In all the cases was inside the therapeutically range. These results showed the potential of these modifications in order to develop implants that can carry different molecules of medical importance.

Nanocolumnar coatings with selective behavior towards osteoblast and Staphylococcus aureus proliferation.

Bacterial colonization and biofilm formation on orthopedic implants is one of the worst scenarios in orthopedic surgery, in terms of both patient prognosis and healthcare costs. Tailoring the surfaces of implants at the nanoscale to actively promote bone bonding while avoiding bacterial colonization represents an interesting challenge to achieving better clinical outcomes. Herein, a Ti6Al4V alloy of medical grade has been coated with Ti nanostructures employing the glancing angle deposition technique by magnetron sputtering. The resulting surfaces have a high density of nanocolumnar structures, which exhibit strongly impaired bacterial adhesion that inhibits biofilm formation, while osteoblasts exhibit good cell response with similar behavior to the initial substrates. These results are discussed on the basis of a "lotus leaf effect" induced by the surface nanostructures and the different sizes and biological characteristics of osteoblasts and Staphylococcus aureus.

Influence of the nanostructure of F-doped TiO2 films on osteoblast growth and function.

The aim of this study was to evaluate the proliferation and mineralization ability of mouse osteoblastic MC3T3-E1 cells on F-containing TiO2 films with different morphology and nanostructure that previously confirmed antibacterial properties. F-containing TiO2 films were fabricated by anodizing Ti-6Al-4V alloy ELI -grade 23. By using a mixture of H2SO4/HF acid at 20 V for 5 and 60 min, a TiO2 film grows with nanoporous (NP) and nanotubular (NT) features, characterized with a pore diameter of 20 and 100 nm, respectively. Fluoride-TiO2 barrier films (FBL) were produced in 1M NH4H2PO4/0.15M NH4F solution at constant voltage controlled at 20 V for 120 min. The amount of F incorporated in the nanostructured oxide films was 6 at % and of 4 at %, for the NP and NT, respectively, while for the FBL film was 12 at %. MC3T3-E1 cells exhibited different behavior when seeded and grown onto these surfaces. Thus, F-doped TiO2 films with NP structures increased proliferation as well as osteogenic gene expression and the mineralization capacity of these osteoblastic cells. These results confirm that anodizing process is suitable to fabricate multifunctional surfaces on Ti-6Al-4V alloy with improved not only antibacterial but also osteogenic properties useful for bone fixation of prosthetic devices

Osteomyelitis: a descriptive study.

BACKGROUND: To analyze the incidence and clinical-microbiological characteristics of osteomyelitis (OM) in a tertiary Spanish hospital. METHODS: All cases diagnosed with OM between January 2007 and December 2010 were retrospectively reviewed. The variables examined include epidemiological characteristics, risk factors, affected bone, radiographic changes, histology, microbiological culture results, antibiotic treatment, and the need for surgery. RESULTS: Sixty-three cases of OM were diagnosed. Twenty-six patients (41.3%) had acute OM whereas 37 patients (58.7%) were classified as chronic OM. OM may result from haematogenous or contiguous microbial seeding. In this group, 49 patients (77.8%) presented with OM secondary to a contiguous source of infection and 14 patients had hematogenous OM (22.2%). Staphylococcus aureus was the most commonly found microorganism. CONCLUSIONS: OM mainly affected patients with risk factors related to the presence of vascular diseases. Antibiotic treatment must be guided by susceptibility patterns of individual microorganisms, although it must be performed together with surgery in most of the cases.

Doped TiO2 anodic layers of enhanced antibacterial properties.

Ti-6Al-4V joint replacement implants foster uncemented fixation in orthopaedic surgery. However, bacterial colonization competes with host cells and ultimately may produce implant-related difficult-to-treat infections, justifying the efforts to obtain infection-resistant materials. In a previous work, the authors demonstrated the antibacterial properties of anodic fluoride-TiO2 nanostructured layers on Ti-6Al-4V alloy. In this work, the anodizing bath has been modified in order to grow fluoride-TiO2 barrier layers (FBL). A bacterial adherence protocol, run with reference and six different clinical strains of Staphylococcus aureus and Staphylococcus epidermidis, showed a statistically significant decrease in the percentage of covered surface (p<0.0001, Kruskal-Wallis test) for FBL specimens when compared with non fluoride-containing specimens, i.e. chemically polished Ti-6Al-4V and F-free TiO2 barrier layers. The results obtained on the F-barrier layers allowed discrimination between the effects of the presence of fluoride in the layer and the layer nanostructure on bacterial adhesion.

In vitro assessment of Staphylococcus epidermidis and Staphylococcus aureus adhesion on TiO2 nanotubes on Ti-6Al-4V alloy.

The aim of this study was to evaluate Staphylococcus sp. adhesion to modified surfaces of titanium alloy (Ti-6Al-4V). Specimens of Ti-6Al-4V alloy 6-4 ELI-grade 23 that meets the requirements of ASTM F136 2002A (AMS 2631B class A1) were anodized in a mixture of sulfuric/hydrofluoric acid at 20 V for 5 and 60 min to form nanoporous (NP) and nanotubular (NT) oxide layers with pore diameter of 20 and 100 nm, respectively. The amount of fluorine incorporated in the oxide films from the electrolyte was 6 and 4 wt %, respectively. Bacterial adherence was studied using laboratory strains and six clinical strains each of Staphylococcus aureus and Staphylococcus epidermidis. Lower adherence of laboratory strains was demonstrated on fluoride nanostructured surfaces in comparison with the fluoride-free surfaces. Significant differences between clinical strains and laboratory strains were also found (p < 0.0001, Kruskal-Wallis test) when NP and NT specimens were compared with chemically polished (CP) surfaces. The results of the tests using multiple clinical strains confirmed a decrease in bacterial adherence on F-containing titanium oxide surfaces, suggesting a potential applicability of this surface, with a confirmed added value of decreasing clinical staphylococci adherence, for medical prosthetic devices.