Biofilm Development by Mycobacterium avium Complex Clinical Isolates: Effect of Clarithromycin in Ultrastructure.

BACKGROUND: The Mycobacterium avium complex includes the commonest non-tuberculous mycobacteria associated with human infections. These infections have been associated with the production of biofilms in many cases, but there are only a few studies about biofilms produced by the species included in this group. METHODS: Three collection strains (M. avium ATCC25291, M. intracellulare ATCC13950, and M. chimaera DSM756), three clinically significant strains (647, 657, and 655), and three clinically non-significant ones (717, 505, and 575) of each species were included. The clinical significance of the clinical isolates was established according to the internationally accepted criteria. The biofilm ultrastructure was studied by Confocal-Laser Scanning Microscopy by using BacLight Live-Dead and Nile Red stains. The viability, covered surface, height, and relative autofluorescence were measured in several images/strain. The effect of clarithromycin was studied by using the technique described by Muñoz-Egea et al. with modifications regarding incubation time. The study included clarithromycin in the culture medium at a concentration achievable in the lungs (11.3 mg/L), using one row of wells as the control without antibiotics. The bacterial viability inside the biofilm is expressed as a percentage of viable cells. The differences between the different parameters of the biofilm ultrastructure were analyzed by using the Kruskal-Wallis test. The correlation between bacterial viability in the biofilm and treatment time was evaluated by using Spearman's rank correlation coefficient (ρ). RESULTS: The strains showed differences between them with all the studied parameters, but neither a species-specific pattern nor a clinical-significance-specific pattern were detected. For the effect of clarithromycin, the viability of the bacteria contained in the biofilm was inversely proportional to the exposure time of the biofilm (ρ > -0.3; p-value < 0.05), excluding two M. chimaera strains (M. chimaera DSM756 and 575), which showed a weak positive correlation with treatment time (0.2 < ρ < 0.39; p-value < 0.05). Curiously, despite a clarithromycin treatment of 216 h, the percentage of the biofilm viability of the strains evaluated here was not less than 40% at best (M. avium 717). CONCLUSIONS: All the M. avium complex strains studied can form biofilm in vitro, but the ultrastructural characteristics between them suggest that these are strain-specific characteristics unrelated to the species or the clinical significance. The clarithromycin effect on MAC species is biofilm-age/time-of-treatment-dependent and appears to be strain-specific while being independent of the clinical significance of the strain.

Mycobacterium biofilms.

The genus Mycobacterium includes some of the deadliest pathogens of History (Mycobacterium tuberculosis, Mycobacterium leprae), but most of the species within the genus are environmental microorganisms. Because some of these nontuberculous mycobacteria (NTM) species can be human pathogens, the study of these mycobacterial biofilms has increased during the last decades, and the interest in this issue increased as well as the growing number of patients with diseases caused by NTM. Different molecular mechanisms have been described, being especially well known the importance of glycopeptidolipids. Moreover, the knowledge of the extracellular matrix has shown important differences with other microorganisms, especially because of the presence of lipidic molecules as a key component of this structure. The clinical importance of mycobacterial biofilms has been described for many chronic diseases, especially lung diseases and implant-related ones, both in vitro and in vivo, and even in patients. Moreover, the biofilm-producing capacity has been proven also in M. tuberculosis, while its importance is not well understood. Biofilm studies have also shown the increasing resistance of mycobacteria in sessile form, and the importance of this resistance in the management of the patients is beyond doubt, being surgery necessary in some cases to cure the patients. Diagnosis of mycobacterial diseases is still based on culture-based techniques designed for the detection of M. tuberculosis. Molecular biology-based methods are also broadly used but again designed for tuberculosis diagnosis. Antimicrobial susceptibility testing is also well developed for tuberculosis, but only some species of NTM have standardized techniques for this purpose. New tools or approaches are necessary to treat these patients, whose importance is increasing, as the number of potential hosts is also increasing throughout the world.

Impact of sink removal from intensive care unit rooms on the consumption of antibiotics and on results of Zero Resistance Project

IntroductionDue to the favourable impact of removing the sinks on isolations in bronchoaspirate samples of patients with mechanical ventilation, we now evaluate the impact on the consumption of antibiotics as well as on the results of the Zero Resistance Project (ZRP).Patients and methodsAll the patients admitted to the unit in a quasi-experimental before–after study with a pre-intervention period between 2014 and 2016 and a post-intervention period from 2016 to 2017, to evaluate antibiotic consumption in defined daily doses, and until 2018, to evaluate the ZRP indicators. The intervention was the removal of the sinks from the rooms of the ICU. We evaluated antibiotic consumption densities and their ratios, grouped as Enterobacteriaceae and non-fermenting gram-negative bacilli (NFGNB) according to their antibiograms; the absolute number of ‘antibiotic days’, ‘hospitalised days’, ‘isolation days’, and ‘multi-resistant bacteria (MRB) days’; as well as their incidence densities per 1000 hospitalised days and the ratio between the two years prior to and the two years after the intervention.ResultsPost-intervention antibiotic use was 1.61-fold (1.60–1.62) and 2.24-fold (2.10–2.37) lower for antibiotics used against Enterobacteriaceae and NFGNB, respectively. There were also reductions in the number of days of antibiotic use by 1.29-fold (1.22–1.36), number of MRB days by 1.84-fold (1.63–2.08), and number of patient isolation days by 1.51-fold (1.38–1.66).DiscussionThe results suggest that the intervention had a favourable impact on the consumption of antibiotics, as well as on the number of days on antibiotics, MRB, and isolation.

Impact of sink removal from intensive care unit rooms on the consumption of antibiotics and on results of Zero Resistance Project.

INTRODUCTION: Due to the favourable impact of removing the sinks on isolations in bronchoaspirate samples of patients with mechanical ventilation, we now evaluate the impact on the consumption of antibiotics as well as on the results of the Zero Resistance Project (ZRP). PATIENTS AND METHODS: All the patients admitted to the unit in a quasi-experimental before-after study with a pre-intervention period between 2014 and 2016 and a post-intervention period from 2016 to 2017, to evaluate antibiotic consumption in defined daily doses, and until 2018, to evaluate the ZRP indicators. The intervention was the removal of the sinks from the rooms of the ICU. We evaluated antibiotic consumption densities and their ratios, grouped as Enterobacteriaceae and non-fermenting gram-negative bacilli (NFGNB) according to their antibiograms; the absolute number of 'antibiotic days', 'hospitalised days', 'isolation days', and 'multi-resistant bacteria (MRB) days'; as well as their incidence densities per 1000 hospitalised days and the ratio between the two years prior to and the two years after the intervention. RESULTS: Post-intervention antibiotic use was 1.61-fold (1.60-1.62) and 2.24-fold (2.10-2.37) lower for antibiotics used against Enterobacteriaceae and NFGNB, respectively. There were also reductions in the number of days of antibiotic use by 1.29-fold (1.22-1.36), number of MRB days by 1.84-fold (1.63-2.08), and number of patient isolation days by 1.51-fold (1.38-1.66). DISCUSSION: The results suggest that the intervention had a favourable impact on the consumption of antibiotics, as well as on the number of days on antibiotics, MRB, and isolation.

Updated Review on the Mechanisms of Pathogenicity in Mycobacterium abscessus, a Rapidly Growing Emerging Pathogen.

In recent years, Mycobacterium abscessus has appeared as an emerging pathogen, with an increasing number of disease cases reported worldwide that mainly occur among patients with chronic lung diseases or impaired immune systems. The treatment of this pathogen represents a challenge due to the multi-drug-resistant nature of this species and its ability to evade most therapeutic approaches. However, although predisposing host factors for disease are well known, intrinsic pathogenicity mechanisms of this mycobacterium are still not elucidated. Like other mycobacteria, intracellular invasiveness and survival inside different cell lines are pathogenic factors related to the ability of M. abscessus to establish infection. Some of the molecular factors involved in this process are well-known and are present in the mycobacterial cell wall, such as trehalose-dimycolate and glycopeptidolipids. The ability to form biofilms is another pathogenic factor that is essential for the development of chronic disease and for promoting mycobacterial survival against the host immune system or different antibacterial treatments. This capability also seems to be related to glycopeptidolipids and other lipid molecules, and some studies have shown an intrinsic relationship between both pathogenic mechanisms. Antimicrobial resistance is also considered a mechanism of pathogenicity because it allows the mycobacterium to resist antimicrobial therapies and represents an advantage in polymicrobial biofilms. The recent description of hyperpathogenic strains with the potential interhuman transmission makes it necessary to increase our knowledge of pathogenic mechanisms of this species to design better therapeutic approaches to the management of these infections.

State-of-the-art treatment strategies for nontuberculous mycobacteria infections.

INTRODUCTION: Non-tuberculous Mycobacteria (NTM) are a group of organisms whose importance in medicine seems to be increasing in recent times. The increasing number of patients susceptible to these diseases make it necessary to expand our knowledge of therapeutic options and to explore future possibilities for the development of a therapeutic arsenal. AREAS COVERED: In this review, the authors provide a brief introduction about the present importance of NTM and describe the present recommendations of the available guidelines for their treatment. They include a description of the future options for the management of these patients, especially focusing on new antibiotics. The authors also look at possibilities for future therapeutic options, such as antibiofilm strategies. EXPERT OPINION: No actual changes have been made to the current recommendations for the management of most NTM infections (except perhaps the availability of nebulized amikacin). However, it is also true that we have increased the number of available antibiotic treatment options with good in vitro activity against NTM. The use of these drugs in selected cases could increase the therapeutic possibilities. However, some problems are still present, such as the knowledge of the actual meaning of a NTM isolate, and will probably be a key part of future research.

Inhibition of Mycobacterium abscessus, M. chelonae, and M. fortuitum biofilms by Methylobacterium sp.

Methylobacterium sp. is isolated from water distribution systems and has been linked in the biofilms of the systems with a lower presence of Mycobacterium avium. In this study we aimed to determine the in vitro activity of Methylobacterium sp. in the development of rapidly growing mycobacteria (RGM) biofilms. Methylobacterium sp. CECT 7805 was added as a suspension of living bacteria (LB), an autoclaved suspension (AS), and an extract obtained after sonication (ES) at different times (24, 48, and 72 h), to preformed biofilms of Mycobacterium abscessus DSM 44196, Mycobacterium chelonae ATCC 19235, and Mycobacterium fortuitum ATCC 6841, using a 96 h control of each species. The biofilms were analyzed by confocal laser scanning microscopy and by the Calgary biofilm device using the plates MBECTM Biofilm Inoculator. A statistically significant reduction in the thickness and covered surface was observed in all mycobacterial biofilms with all forms of Methylobacterium sp. A statistically significant increase in the autofluorescence was observed in M. abscessus biofilms but not in other biofilms. The increased percentage of dead mycobacteria was statistically significant in all cases. The reduced log CFU (colony-forming units)/peg recount was statistically significant in M. chelonae biofilms after treatment with AS and ES, but in M. fortuitum biofilms the recount decreased only with AS. M. abscessus biofilms were always significantly reduced with AS at 72 h and with ES. Methylobacterium sp. could inhibit RGM biofilm formation. Living cells of Methylobacterium sp. were not necessary to inhibit the growth of a preformed biofilm. M. chelonae biofilms were the most greatly reduced.

Non-pigmented rapidly growing mycobacteria smooth and rough colony phenotypes pathogenicity evaluated using in vitro and experimental models.

Non-pigmented rapidly growing mycobacteria (NPRGM) are widely distributed in water, soil and animals. It has been observed an increasing importance of NPRGM related-infections, particularly due to the high antimicrobial resistance. NPRGM have rough and smooth colony phenotypes, and several studies have showed that rough colony variants are more virulent than smooth ones. However, other studies have failed to validate this observation. In this study, we have performed two models, invitro and in vivo, in order to assess the different pathogenicity of these two phenotypes. We used collection and clinical strains of Mycobacteriumabscessus, Mycobacterium fortuitum and Mycobacteriumchelonae. On the invitro model (macrophages), phagocytosis was higher for M. abscessus and M. fortuitum rough colony variant strains when compared to smooth colony variants. However, we did not find differences with colonial variants of M. chelonae. Survival of Galleriamellonella larvae in the experimental model was lower for M. abscessus and M. fortuitum rough colony variants when compared with larvae infected with smooth colony variants. We did not find differences in larvae infected with M. chelonae.Results of our in vivo study correlated well with the experimental model. This fact could have implications on the interpretation of the clinical significance of the NPRGM isolate colonial 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

Impacto de la retirada de los lavabos en una unidad de cuidados intensivos sobre los aislamientos por bacilos gramnegativos no fermentadores en pacientes con ventilación mecánica invasiva / Impact of removing sinks from an intensive care unit on isolations by gram-negative non-fermenting bacilli in patients with invasive mechanical ventilation

Introducción y objetivo: La contaminación de los lavabos, incluso por su infrautilización, se asocia a la transmisión de bacilos gramnegativos no fermentadores (BGNNF) en unidades que atienden a pacientes con alto riesgo de infección. Tras vigilancia previa con muestras ambientales y de pacientes, se explora ahora el impacto de la retirada de los lavabos de los boxes de una UCI sobre aislamientos incidentes relacionados con la atención sanitaria en muestras de broncoaspirado de pacientes con ventilación mecánica invasiva (VMI). Material y métodos: Estudio cuasiexperimental antes-después, con anualidades preintervención y postintervención correspondientes a los períodos abril 2014-2016 y abril 2016-2017, respectivamente. Se estudiaron las densidades de incidencia por 1.000 días de VMI comparándose por el método exacto basado en la distribución binomial y estimándose la razón de densidades de incidencia. Resultados: Las densidades de incidencia por 1.000 días de VMI de aislamientos por BGNNF en las muestras de broncoaspirado de los períodos pre y postintervención fueron 11,28 y 1,91, respectivamente, lo que supone una densidad de incidencia postintervención 5,90 veces menor que la previa (IC95%: 1,49-51,05; p=0,003). Conclusiones: A pesar de las limitaciones del diseño, la retirada de los lavabos apunta a una reducción de los aislamientos

Introduction and objective: Contamination of sinks, even due to their underuse, is associated with the transmission of non-fermenting gram-negative bacilli (NFGNB) to patients in Augmented Care Units. After previous monitoring with environmental and patient samples, we now explore the impact of removing sinks from ICU cubicles on incidental isolations related to health care in bronchoaspirate samples of patients with invasive mechanical ventilation (IMV). Material and methods: Quasi-experimental study, before-and-after, pre-intervention annuities April 2014-2016 and post-intervention April 2016-2017. Incidence densities per 1,000 days of IMV were studied, comparing by the exact method based on the binomial distribution and estimating the incidence density ratio. Results: The incidence densities per 1,000 days of IMV of isolations by NFGNB in bronchoaspirate samples of the pre and post-intervention periods were 11.28 and 1.9, respectively. This implies a post-intervention incidence density 5.90 times lower than before (95% CI: 1.49-51.05, P=.003). Conclusions: Despite of the limitations of the design, the removal of sinks showed a reduction of the isolations

Impact of removing sinks from an intensive care unit on isolations by gram-negative non-fermenting bacilli in patients with invasive mechanical ventilation. / Impacto de la retirada de los lavabos en una unidad de cuidados intensivos sobre los aislamientos por bacilos gramnegativos no fermentadores en pacientes con ventilación mecánica invasiva.

INTRODUCTION AND OBJECTIVE: Contamination of sinks, even due to their underuse, is associated with the transmission of non-fermenting gram-negative bacilli (NFGNB) to patients in Augmented Care Units. After previous monitoring with environmental and patient samples, we now explore the impact of removing sinks from ICU cubicles on incidental isolations related to health care in bronchoaspirate samples of patients with invasive mechanical ventilation (IMV). MATERIAL AND METHODS: Quasi-experimental study, before-and-after, pre-intervention annuities April 2014-2016 and post-intervention April 2016-2017. Incidence densities per 1,000 days of IMV were studied, comparing by the exact method based on the binomial distribution and estimating the incidence density ratio. RESULTS: The incidence densities per 1,000 days of IMV of isolations by NFGNB in bronchoaspirate samples of the pre and post-intervention periods were 11.28 and 1.9, respectively. This implies a post-intervention incidence density 5.90 times lower than before (95% CI: 1.49-51.05, P=.003). CONCLUSIONS: Despite of the limitations of the design, the removal of sinks showed a reduction of the isolations.

La infrautilización de grifos en una unidad de cuidados intensivos como causa de reservorios de bacilos gramnegativos no fermentadores / Under-utilization of taps in intensive care unit as a cause of reservoirs of nonfermenting gram-negative bacilli

INTRODUCCIÓN: La infrautilización de grifos se relaciona con reservorios de bacilos gramnegativos no fermentadores en su interior con capacidad de diseminación. Se describe la detección del problema y abordaje en una UCI. MÉTODOS: Estudio descriptivo en una UCI con boxes individuales con lavabo propio. Se recogieron muestras clínicas de pacientes y ambientales de los aireadores de los grifos. Se revisaron medidas de higiene. RESULTADOS: Se identificaron 4 casos de Chryseobacterium indologenes, uno de Elizabethkingia meningoseptica y otro por Pseudomonas aeruginosa, tanto en muestras clínicas como ambientales. Los profesionales indicaron utilizar solución hidroalcohólica casi siempre en la higiene de manos. Tras descartar la apertura controlada diaria de grifos por ineficiente, se decidió su retirada. CONCLUSIONES: Las recomendaciones nacionales resultaron insuficientes para la prevención, detección y control de la contaminación de los grifos de una unidad de alto riesgo de infección. Es necesario mejorar el manejo de los grifos en estas unidades

INTRODUCTION: The under-utilisation of taps is associated with the generation of reservoirs of non-fermenting gram-negative bacilli with the ability to disseminate. We describe the detection and approach of the problem in an ICU. METHODS: Observational descriptive study in an ICU with individual cubicles with their own sink. We collected clinical samples from patients and environmental samples from tap aerators and reviewed the unit's hygiene measures. RESULTS: We detected four cases due to Chryseobacterium indologenes, one to Elizabethkingia meningoseptica and another to Pseudomonas aeruginosa; they were identified both in clinical and the environmental samples. The healthcare professionals reported that almost every hand hygiene opportunity was performed with a hydroalcoholic solution. After considered the daily flushing of water outlets as inefficient, it was decided to remove them. CONCLUSIONS: National recommendations were insufficient for preventing, detecting and controlling tap contamination in units with a high risk of infection. The management of taps in these units needs to be improved

Under-utilization of taps in intensive care unit as a cause of reservoirs of nonfermenting gram-negative bacilli. / La infrautilización de grifos en una unidad de cuidados intensivos como causa de reservorios de bacilos gramnegativos no fermentadores.

INTRODUCTION: The under-utilisation of taps is associated with the generation of reservoirs of non-fermenting gram-negative bacilli with the ability to disseminate. We describe the detection and approach of the problem in an ICU. METHODS: Observational descriptive study in an ICU with individual cubicles with their own sink. We collected clinical samples from patients and environmental samples from tap aerators and reviewed the unit's hygiene measures. RESULTS: We detected four cases due to Chryseobacterium indologenes, one to Elizabethkingia meningoseptica and another to Pseudomonas aeruginosa; they were identified both in clinical and the environmental samples. The healthcare professionals reported that almost every hand hygiene opportunity was performed with a hydroalcoholic solution. After considered the daily flushing of water outlets as inefficient, it was decided to remove them. CONCLUSIONS: National recommendations were insufficient for preventing, detecting and controlling tap contamination in units with a high risk of infection. The management of taps in these units needs to be improved.

Mycobacterium bovis and Other Uncommon Members of the Mycobacterium tuberculosis Complex.

Since its discovery by Theobald Smith, Mycobacterium bovis has been a human pathogen closely related to animal disease. At present, M. bovis tuberculosis is still a problem of importance in many countries and is considered the main cause of zoonotic tuberculosis throughout the world. Recent development of molecular epidemiological tools has helped us to improve our knowledge about transmission patterns of this organism, which causes a disease indistinguishable from that caused by Mycobacterium tuberculosis. Diagnosis and treatment of this mycobacterium are similar to those for conventional tuberculosis, with the important exceptions of constitutive resistance to pyrazinamide and the fact that multidrug-resistant and extremely drug-resistant M. bovis strains have been described. Among other members of this complex, Mycobacterium africanum is the cause of many cases of tuberculosis in West Africa and can be found in other areas mainly in association with immigration. M. bovis BCG is the currently available vaccine for tuberculosis, but it can cause disease in some patients. Other members of the M. tuberculosis complex are mainly animal pathogens with only exceptional cases of human disease, and there are even some strains, like "Mycobacterium canettii," which is a rare human pathogen that could have an important role in the knowledge of the evolution of tuberculosis in the history.

Effect of Antibiotics and Antibiofilm Agents in the Ultrastructure and Development of Biofilms Developed by Nonpigmented Rapidly Growing Mycobacteria.

We analyze the effect of amikacin, ciprofloxacin, and clarithromycin, alone and associated with N-acetylcysteine (NAC) and Tween 80, at different times and concentrations in nonpigmented rapidly growing mycobacteria (NPRGM) biofilms. For this purpose, confocal laser scanning microscopy and image analysis were used to study the development and behavior of intrinsic autofluorescence, covered area, thickness, and cell viability in NPRGM biofilms after adding antibiotics alone and associated with antibiofilm agents. In this study, ciprofloxacin is the most active antibiotic against this type of biofilm and thickness is the most affected parameter. NAC and Tween 80 combined with antibiotics exert a synergistic effect in increasing the percentage of dead bacteria and also reducing the percentage of covered surface and thickness of NPRGM biofilms. Tween 80 seems to be an antibiofilm agent more effective than NAC due to its higher reduction in the percentage of cover surface and thickness. In conclusion, the results obtained in this work show that phenotypic parameters (thickness, percentage of covered surface, autofluorescence, percentage of live/dead bacteria) are affected by combining antibiotics and antibiofilm agents, ciprofloxacin and Tween 80 being the most active agents against NPRGM biofilms.

Effect of ciprofloxacin in the ultrastructure and development of biofilms formed by rapidly growing mycobacteria.

BACKGROUND: The aim of this study was to analyze the effect of ciprofloxacin at different times on the development and behavior of intrinsic autofluorescence, covered area, thickness and cell viability in a biofilm formed by non-pigmented rapidly growing mycobacteria (NPRGM).Confocal laser scanning microscopy and image analysis were used to study the behavior of ciprofloxacin on biofilms. RESULTS: Thickness was the most affected parameter, although some species showed changes in other parameters. At the same time, we also measured the minimum inhibitory concentration and the minimum biofilm eradication concentration (MBEC). An increase in MBEC was observed in all the strains, M. peregrinum being the species that presented the highest increase. CONCLUSIONS: This study help us to understand better how mycobacterial biofims can be affected by ciprofloxacin.

Sensibilidad in vitro de biopelículas de micobacterias de crecimiento rápido frente a diferentes antimicrobianos / In vitro susceptibility of rapidly growing mycobacteria biofilms against different antimicrobials

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Clinical and microbiological characteristics of patients with septic arthritis: A hospital-based study.

BACKGROUND: To determine the clinical and epidemiological characteristics, etiology, underlying conditions, and outcomes of patients with primary septic arthritis and no prosthetic joints at a university hospital. METHODS: A retrospective study was performed between 2005 and 2012. Records from the Microbiology Department were reviewed, and patients with a positive culture of synovial fluid or biopsy were selected for the study. Clinical charts were reviewed using a designed protocol. RESULTS: 41 patients were diagnosed with septic arthritis with a positive culture. Most were diagnosed with monoarticular (85.37%) and monomicrobial (92.68%) arthritis. The most commonly involved joint was the knee (34.15%). The most frequent underlying conditions were hypertension and diabetes mellitus. Staphylococcus aureus was the most common pathogen (58.54%). Two cases of chronic arthritis, both caused by Mycobacterium tuberculosis were detected. The most frequently used antibiotic combinations were cloxacillin + ciprofloxacin and vancomycin + ciprofloxacin. Surgical treatment included needle aspiration, open joint debridement, or arthroscopic techniques. Twelve cases had a poor outcome (destructive articular disease), and 3 patients died from staphylococcal sepsis. CONCLUSIONS: In our hospital, septic arthritis is primarily acute, monoarticular, and monomicrobial; affects higher joints, is caused by S. aureus, and occurs in adult patients with underlying diseases. Outcome is good in most patients, although more than 25% of cases had articular sequels.

Kingella kingae keratitis.

We present the first two cases of Kingella kingae keratitis in adults. This species is a rare isolate from ophthalmic samples for which final identification was obtained with matrix-assisted laser desorption ionization-time of flight mass spectrometry. One of the patients recovered uneventfully with topical therapy. Results from the second patient cannot be confirmed as he was lost to follow-up.