Nasal Iodophor Antiseptic vs Nasal Mupirocin Antibiotic in the Setting of Chlorhexidine Bathing to Prevent Infections in Adult ICUs: A Randomized Clinical Trial.

Importance: Universal nasal mupirocin plus chlorhexidine gluconate (CHG) bathing in intensive care units (ICUs) prevents methicillin-resistant Staphylococcus aureus (MRSA) infections and all-cause bloodstream infections. Antibiotic resistance to mupirocin has raised questions about whether an antiseptic could be advantageous for ICU decolonization. Objective: To compare the effectiveness of iodophor vs mupirocin for universal ICU nasal decolonization in combination with CHG bathing. Design, Setting, and Participants: Two-group noninferiority, pragmatic, cluster-randomized trial conducted in US community hospitals, all of which used mupirocin-CHG for universal decolonization in ICUs at baseline. Adult ICU patients in 137 randomized hospitals during baseline (May 1, 2015-April 30, 2017) and intervention (November 1, 2017-April 30, 2019) were included. Intervention: Universal decolonization involving switching to iodophor-CHG (intervention) or continuing mupirocin-CHG (baseline). Main Outcomes and Measures: ICU-attributable S aureus clinical cultures (primary outcome), MRSA clinical cultures, and all-cause bloodstream infections were evaluated using proportional hazard models to assess differences from baseline to intervention periods between the strategies. Results were also compared with a 2009-2011 trial of mupirocin-CHG vs no decolonization in the same hospital network. The prespecified noninferiority margin for the primary outcome was 10%. Results: Among the 801 668 admissions in 233 ICUs, the participants' mean (SD) age was 63.4 (17.2) years, 46.3% were female, and the mean (SD) ICU length of stay was 4.8 (4.7) days. Hazard ratios (HRs) for S aureus clinical isolates in the intervention vs baseline periods were 1.17 for iodophor-CHG (raw rate: 5.0 vs 4.3/1000 ICU-attributable days) and 0.99 for mupirocin-CHG (raw rate: 4.1 vs 4.0/1000 ICU-attributable days) (HR difference in differences significantly lower by 18.4% [95% CI, 10.7%-26.6%] for mupirocin-CHG, P < .001). For MRSA clinical cultures, HRs were 1.13 for iodophor-CHG (raw rate: 2.3 vs 2.1/1000 ICU-attributable days) and 0.99 for mupirocin-CHG (raw rate: 2.0 vs 2.0/1000 ICU-attributable days) (HR difference in differences significantly lower by 14.1% [95% CI, 3.7%-25.5%] for mupirocin-CHG, P = .007). For all-pathogen bloodstream infections, HRs were 1.00 (2.7 vs 2.7/1000) for iodophor-CHG and 1.01 (2.6 vs 2.6/1000) for mupirocin-CHG (nonsignificant HR difference in differences, -0.9% [95% CI, -9.0% to 8.0%]; P = .84). Compared with the 2009-2011 trial, the 30-day relative reduction in hazards in the mupirocin-CHG group relative to no decolonization (2009-2011 trial) were as follows: S aureus clinical cultures (current trial: 48.1% [95% CI, 35.6%-60.1%]; 2009-2011 trial: 58.8% [95% CI, 47.5%-70.7%]) and bloodstream infection rates (current trial: 70.4% [95% CI, 62.9%-77.8%]; 2009-2011 trial: 60.1% [95% CI, 49.1%-70.7%]). Conclusions and Relevance: Nasal iodophor antiseptic did not meet criteria to be considered noninferior to nasal mupirocin antibiotic for the outcome of S aureus clinical cultures in adult ICU patients in the context of daily CHG bathing. In addition, the results were consistent with nasal iodophor being inferior to nasal mupirocin. Trial Registration: ClinicalTrials.gov Identifier: NCT03140423.

Absence of Staphylococcus aureus in Wild Populations of Fish Supports a Spillover Hypothesis.

Staphylococcus aureus is a human commensal and opportunistic pathogen that also infects other animals. In humans and livestock, where S. aureus is most studied, strains are specialized for different host species. Recent studies have also found S. aureus in diverse wild animals. However, it remains unclear whether these isolates are also specialized for their hosts or whether their presence is due to repeated spillovers from source populations. This study focuses on S. aureus in fish, testing the spillover hypothesis in two ways. First, we examined 12 S. aureus isolates obtained from the internal and external organs of a farmed fish. While all isolates were from clonal complex 45, genomic diversity indicates repeated acquisition. The presence of a φSa3 prophage containing human immune evasion genes suggests that the source was originally human. Second, we tested for S. aureus in wild fish that were isolated from likely sources. In particular, we sampled 123 brown trout and their environment at 16 sites in the remote Scottish Highlands with variable levels of exposure to humans, birds, and livestock. This screen found no S. aureus infection in any of the wild populations or their environment. Together, these results support that the presence of S. aureus in fish and aquaculture is due to spillover from humans rather than specialization. Given the trends of increasing fish consumption, a better understanding of the dynamics of S. aureus spillover in aquaculture will mitigate future risks to fish and human health. IMPORTANCE Staphylococcus aureus is a human and livestock commensal but also an important pathogen responsible for high human mortality rates and economic losses in farming. Recent studies show that S. aureus is common in wild animals, including fish. However, we do not know whether these animals are part of the normal host range of S. aureus or whether infection is due to repeated spillover events from true S. aureus hosts. Answering this question has implications for public health and conservation. We find support for the spillover hypothesis by combining genome sequencing of S. aureus isolates from farmed fish and screens for S. aureus in isolated wild populations. The results imply that fish are unlikely to be a source of novel emergent S. aureus strains but highlight the prominence of the spillover of antibiotic-resistant bacteria from humans and livestock. This may affect both future fish disease potential and the risk of human food poisoning.

Enzyme-Triggered Transforming of Assembly Peptide-Modified Magnetic Resonance-Tuned Probe for Highly Sensitive Imaging of Bacterial Infection In Vivo.

Confirming bacterial infection at an early stage and distinguishing between sterile inflammation and bacterial infection is still highly needed for efficient treatment. Here, in situ highly sensitive magnetic resonance imaging (MRI) bacterial infection in vivo based on a peptide-modified magnetic resonance tuning (MRET) probe (MPD-1) that responds to matrix metallopeptidase 2 (MMP-2) highly expressed in bacteria-infected microenvironments is achieved. MPD-1 is an assembly of magnetic nanoparticle (MNP) bearing with gadolinium ion (Gd3+ ) modified MMP-2-cleavable self-assembled peptide (P1 ) and bacteria-targeting peptide (P), and it shows T2 -weighted signal due to the assemble of MNP and MRET ON phenomenon between MNP assembly and Gd3+ . Once MPD-1 accumulates at the bacterially infected site, P1 included in MPD-1 is cleaved explicitly by MMP-2, which triggers the T2 contrast agent of MPD-1 to disassemble into the monomer of MNP, leading the recovery of T1 -weighted signal. Simultaneously, Gd3+ detaches from MNP, further enhancing the T1 -weighted signal due to MRET OFF. The sensitive MRI of Staphylococcus aureus (low to 104 CFU) at the myositis site and accurate differentiation between sterile inflammation and bacterial infection based on the proposed MPD-1 probe suggests that this novel probe would be a promising candidate for efficiently detecting bacterial infection in vivo.

Isolation and characterization of bacteria residing in the oral, gut, and fecal samples of different pheasant species / Isolamento e caracterização de bactérias residentes nas amostras orais, intestinais e fecais de diferentes espécies de faisão

There is a paucity of research conducted on microbial prevalence in pheasants. The microbiota of captive birds has zoonotic significance and must be characterize. Present study is therefore planned to assess the microbiota from oral, fecal and gut content of captive avian species. It will be helpful in characterization of harmful microbes. Different samples taken from oral, gut and feces of ring-necked pheasants (Phasianus colchicus), green pheasants (Phasianus versicolor), golden pheasant (Chrysolophus pictus) and silver pheasant (Lophura nycthemera). Samples were collected, diluted, and inoculated onto different agar plates (MacConkey, SS agar, MSA and nutrient agar) for cultivation of bacterial species. Colonies of E.coli, Staphylococcus spp. Brachyspira spp. and Campylobacter spp were observed based on colony morphology. Colony forming unit showed E. coli as frequently found bacteria in fecal, oral and gut contents of all the above pheasants. The overall significance difference was found among bacterial species of golden pheasants, green pheasant, ring-necked pheasant, and silver pheasants. It was concluded that E.coli is predominant isolated from heathy pheasants followed by Campylobacter, Staphylococcus and Brachyspira.

Há uma escassez de pesquisas realizadas sobre a prevalência microbiana em faisões. A microbiota de aves em cativeiro tem significado zoonótico e deve ser caracterizada. O presente estudo está, portanto, planejado para avaliar a microbiota do conteúdo oral, fecal e intestinal de espécies aviárias em cativeiro. Será útil na caracterização de micróbios nocivos. Diferentes amostras retiradas da boca, intestino e fezes de faisões de pescoço redondo (Phasianus colchicus), faisões verdes (Phasianus versicolor), faisões dourados (Chrysolophus pictus) e faisão prateado (Lophura nycthemera). As amostras foram coletadas, diluídas e inoculadas em diferentes placas de ágar (MacConkey, ágar SS, MSA e ágar nutriente) para o cultivo de espécies bacterianas. Colônias de E. coli, Staphylococcus spp., Brachyspira spp. e Campylobacter spp foram observados com base na morfologia da colônia. A unidade formadora de colônia mostrou E. coli como bactéria frequentemente encontrada no conteúdo fecal, oral e intestinal de todos os faisões acima. A diferença de significância geral foi encontrada entre as espécies bacterianas de faisões dourados, faisões verdes, faisões de pescoço anelado e faisões prateados. Verificou-se que a E.coli é predominantemente isolada de faisões saudáveis, seguida por Campylobacter, Staphylococcus e Brachyspira.

Effect of polycaprolactone nanocapsules loaded with essential oils on biofilm formation by Staphylococcus aureus strains isolated from bovine mastitis cases

Abstract Bovine infectious mastitis is largely resistant to antibacterial treatment, mainly due to mechanisms of bacterial resistance in the biofilms formed by Staphylococcus aureus. Melaleuca (MEO) and citronella essential oils (CEO) are promising agents for reducing or eliminating biofilms. Free melaleuca oil presented a medium Minimum Inhibitory Concentration (MIC) of 0.625% and a Minimum Bactericidal Concentration (MBC) of 1.250%, while free citronella oil showed medium MIC and MBC of 0.313%. Thus, free CEO and MEO demonstrate bacteriostatic and bactericidal potential. We generated polymeric nanocapsules containing MEO or CEO and evaluated their efficacy at reducing biofilms formed by S. aureus. Glass and polypropylene spheres were used as test surfaces. To compare the responses of free and encapsulated oils, strains were submitted to 10 different procedures, using free and nanoencapsulated essential oils (EOs) in vitro. We observed no biofilm reduction by MEO, free or nanoencapsulated. However, CEO nanocapsules reduced biofilm formation on glass (p=0.03) and showed a tendency to diminish biofilms on polypropylene (p=0.051). Despite nanoencapsulated CEO reducing biofilms in vitro, the formulation could be improved to modify the CEO component polarity and, including MEO, to obtain more interactions with surfaces and the biofilm matrix

Surveillance of osteoarticular infections caused by Staphylococcus aureus in a paediatric hospital in Mexico City.

Staphylococcus aureus is the main aetiologic agent of osteoarticular infections (OAIs) in paediatric patients. The aim of this prospective unicenter study was to describe the phenotypic and genotypic characteristics of S. aureus isolates obtained from OAIs in paediatric patients admitted to tertiary care hospital. Through a surveillance program called OsteoCode, a multidisciplinary team was created and we identified 27 patients with OAIs caused by S. aureus from 2019 to 2021. The susceptibility profile, virulence factors, biofilm formation, pulsed-field gel electrophoresis (PFGE), clonal complex (CC) and sequence type (ST) were determined. In addition, the clinical characteristics and evolution of the patients presented six months after the diagnosis of OAIs were described. Ninety-two percent of the isolates were methicillin-sensitive S. aureus (MSSA). In methicillin-resistant S. aureus (MRSA), SCCmec-II and SCCmec-V were detected. The pvl gene was only observed in MSSA (18.5%) and was associated with highest fever (p=0.015), multiple localization (p=0.017), and soft tissue sites of infection beyond the bone (pyomyositis, pulmonary abscess) (p=0.017). Biofilm formation was detected in 55.6% of isolates. The most common CC were CC5 and CC30 which represent the most common linages for bone and joint infections worldwide. The isolates were distributed in different STs, and ST672 was predominant. MRSA were associated with a longer duration of intravenous treatment and a prolonged hospital stay (p=0.023). Recurrent infection occurred in five children and orthopaedic complications in 33.3% of patients. This is the first study that reflects the epidemiology of S. aureus in OAIs in paediatric patients in Mexico; a clear predominance of MSSA distributed in different STs was observed. Our findings highlight that a multidisciplinary team is required for the diagnosis and treatment of OAIs.

Prevalencia de portación nasal de Staphylococcus aureus sensible y resistente a la meticilina en candidatos a artroplastia total de cadera o rodilla / Prevalence of nasal carriage of methicillin-sensitive and methicillin-resistant Staphylococcus aureus in candidates for total hip or knee arthroplasty

INTRODUCIÓN Las infecciones perioperatorias en cirugía de reemplazo articular son fuente importante de morbimortalidad, así como de altos costos económicos y sociales, tanto para el paciente como para su entorno. La colonización preoperatoria por Staphylococcus aureus ha sido reconocida como un factor de riesgo importante para desarrollar una infección de sitio quirúrgico.El objetivo de este estudio es conocer la prevalencia de portación nasal de S. aureus, tanto sensible a la meticilina (SASM) como resistente a la meticilina (SARM), en pacientes candidatos a cirugía de reemplazo articular de cadera o rodilla. MATERIALES Y MÉTODOS Se realizó un estudio observacional de una cohorte retrospectiva de pacientes con indicación de artroplastia total de cadera (ATC) y rodilla (ATR) electiva por artrosis severa en un hospital público de Chile. Los pacientes fueron sometidos a tamizaje preoperatorio de portación, cultivándose muestras obtenidas mediante hisopado de ambas fosas nasales. Los datos del laboratorio fueron recopilados y presentados como porcentaje de portación de S. aureus. RESULTADOS Se estudiaron 303 pacientes consecutivos de ATC y 343 de ATR. En total, 483 de los 646 pacientes (74,7%) tuvieron estudio preoperatorio de portación nasal. Se identificaron 123 pacientes (25,4%) portadores de S. aureus, de los cuales sólo 2 (0,41%) casos correspondieron a SARM. CONCLUSIÓN La prevalencia de portación nasal de S. aureus obtenida fue de 25%, similar a lo reportado en otras series. La prevalencia de SARM (0.41%), sin embargo, estuvo bajo lo descrito en la literatura internacional (0,6­6%). Sería de utilidad, dada la alta prevalencia de portación descrita en nuestro trabajo y de acuerdo a evidencia publicada recientemente, realizar protocolos de descolonización universales, sin necesidad de realizar tamizaje preoperatorio.

INTRODUCTION Surgical-site infections in joint replacement surgery are an important source of morbidity and mortality that entail high economic and social burden both for the patient and their environment. Preoperative colonization by Staphylococcus aureus has been recognized as an important risk factor for the development of surgical-site infection. The aim of the present study is to determine the prevalence of nasal colonization by S. aureus, both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) in patients who are candidates for total replacement of the hip or knee joints. MATERIALS AND METHODS A retrospective observational study of a cohort of 646 patients with an indication to undergo total hip arthroplasty (THA) or total knee arthroplasty (TKA) due to severe osteoarthritis was performed in a Public Hospital in Chile. The patients were submitted to a preoperative screening for S. aureus carriage, and the culture samples were obtained by swabbing both nostrils. The laboratory data was collected and presented as a percentage of carriage. RESULTS We consecutively examined 303 THA and 343 TKA patients. A total of 483 of the 646 patients (74.7%) underwent a preoperative study of nasal carriage. We identified 123 (25.4%) S. aureus carriers, and only found 2 (0.41%) cases corresponding to MRSA. CONCLUSION We found a prevalence of nasal carriage of S. aureus of 25.4%, a rate similar to that reported in other series. The prevalence of MRSA (0.41%), however, was lower than that reported in the international literature (0.6­6%). Given the high prevalence of carriage described in our work and according to recently published data, it would be worthwhile to carry out universal decolonization protocols, without the need for preoperative screening.

Hand Hygiene among Anesthesiologists and Microorganisms Contamination in Anesthesia Environments: A Single-Center Observational Study.

Objective: To investigate the baseline levels of microorganisms' growth on the hands of anesthesiologists and in the anesthesia environment at a cancer hospital. Methods: This study performed in nine operating rooms and among 25 anesthesiologists at a cancer hospital. Sampling of the hands of anesthesiologists and the anesthesia environment was performed at a ready-to-use operating room before patient contact began and after decontamination. Results: Microorganisms' growth results showed that 20% (5/25) of anesthesiologists' hands carried microorganisms (> 10 CFU/cm 2) before patient contact began. Female anesthesiologists performed hand hygiene better than did their male counterparts, with fewer CFUs ( P = 0.0069) and fewer species ( P = 0.0202). Our study also found that 55.6% (5/9) of ready-to-use operating rooms carried microorganisms (> 5 CFU/cm 2). Microorganisms regrowth began quickly (1 hour) after disinfection, and increased gradually over time, reaching the threshold at 4 hours after disinfection. Staphylococcus aureus was isolated from the hands of 20% (5/25) of anesthesiologists and 33.3% (3/9) of operating rooms. Conclusion: Our study indicates that male anesthesiologists need to pay more attention to the standard operating procedures and effect evaluation of hand hygiene, daily cleaning rate of the operating room may be insufficient, and we would suggest that there should be a repeat cleaning every four hours.

A culture-free biphasic approach for sensitive and rapid detection of pathogens in dried whole-blood matrix.

Blood stream infections (BSIs) cause high mortality, and their rapid detection remains a significant diagnostic challenge. Timely and informed administration of antibiotics can significantly improve patient outcomes. However, blood culture, which takes up to 5 d for a negative result, followed by PCR remains the gold standard in diagnosing BSI. Here, we introduce a new approach to blood-based diagnostics where large blood volumes can be rapidly dried, resulting in inactivation of the inhibitory components in blood. Further thermal treatments then generate a physical microscale and nanoscale fluidic network inside the dried matrix to allow access to target nucleic acid. The amplification enzymes and primers initiate the reaction within the dried blood matrix through these networks, precluding any need for conventional nucleic acid purification. High heme background is confined to the solid phase, while amplicons are enriched in the clear supernatant (liquid phase), giving fluorescence change comparable to purified DNA reactions. We demonstrate single-molecule sensitivity using a loop-mediated isothermal amplification reaction in our platform and detect a broad spectrum of pathogens, including gram-positive methicillin-resistant and methicillin-susceptible Staphylococcus aureus bacteria, gram-negative Escherichia coli bacteria, and Candida albicans (fungus) from whole blood with a limit of detection (LOD) of 1.2 colony-forming units (CFU)/mL from 0.8 to 1 mL of starting blood volume. We validated our assay using 63 clinical samples (100% sensitivity and specificity) and significantly reduced sample-to-result time from over 20 h to <2.5 h. The reduction in instrumentation complexity and costs compared to blood culture and alternate molecular diagnostic platforms can have broad applications in healthcare systems in developed world and resource-limited settings.

Infecciones periprotésicas en artroplastia total de rodilla: ¿cuál es nuestra realidad? / Periprosthetic infections in total knee arthroplasty: what is our reality?

INTRODUCCIÓN La infección periprotésica (IPP) es una de las complicaciones más serias en una artroplastia total de rodilla (ATR). Pese a esto, existe poca literatura chilena respecto de esta patología. OBJETIVOS Determinar la incidencia, las comorbilidades, los microorganismos aislados y su susceptibilidad antibiótica, y la morbimortalidad en pacientes con IPP. MATERIALES Y MÉTODOS Estudio descriptivo y retrospectivo en pacientes operados entre 2001 y 2020 por gonartrosis, con una ATR primaria, en un mismo centro de salud, con al menos 1 año de seguimiento. Se excluyeron pacientes operados en otros centros o con registros clínicos incompletos. Se registraron las comorbilidades, los microorganismos aislados, la susceptibilidad antibiótica, y la sobrevida por medio de una búsqueda sistemática de las fichas clínicas de los pacientes con IPP. Se utilizó estadística descriptiva para presentar los datos. RESULTADOS Se incluyeron 544 ATRs, de las cuales 8 (1,47%) presentaron IPP, y los pacientes tenían una edad promedio de presentación de 66 (±5,7) años, e índice de masa corporal (IMC) promedio de 30,3 (±4,5) kg/m2. La mediana de tiempo de presentación de la IPP fue de 411 (±1.034) días. Las principales comorbilidades registradas fueron hipertensión arterial en 5 (62,5%), tabaquismo en 4 (50%) casos, y dislipidemia in 4 (50%) casos. En total, 5 (62,5%) pacientes presentaron etiología polimicrobiana, y en 3 (37,5%) se aisló un solo microorganismo. Los principales agentes aislados fueron Staphylococcus aureus y Staphylococcus coagulasa negativo, ambos multirresistentes, en 6 (75%) y 3 (37,5%) pacientes respectivamente. Todos los pacientes recibieron tres dosis de cefazolina como profilaxis quirúrgica. Se describe una sensibilidad del 100% frente a vancomicina y rifampicina (12/12 cultivos), y una resistencia del 83,4% al ciprofloxacino (4/9 cultivos). Un total de 2 (25%) pacientes fallecieron después de 3 años de la ATR por causas no relacionadas con la IPP. No hubo casos de recidiva infecciosa tras la revisión. CONCLUSIÓN Se encontró una incidencia de 1,47% (8 casos) de IPP. Todos los pacientes con IPP presentaron alguna comorbilidad prequirúrgica. Los principales agentes microbiológicos identificados fueron multirresistentes y susceptibles a vancomicina y rifampicina.

INTRODUCTION Periprosthetic infection (PPI) is one of the most serious complications in total knee arthroplasty (TKA). Despite this, there is little Chilean literature regarding this pathology. OBJETIVES To determine the incidence, comorbidities, isolated microorganisms and their antibiotic susceptibility, morbidity, and mortality in patients with PPI. MATERIALS AND METHODS A descriptive and retrospective study in patients operated between 2001 and 2020 for gonarthrosis, with a primary TKA, in the same health center, with at least 1 year of follow-up. Patients operated on in other centers or with incomplete clinical records were excluded. Comorbidities, isolated microorganisms, antibiotic susceptibility, and survival were recorded through a systematic search of the clinical records of patients with PPI. Descriptive statistics were used to present the data. RESULTS We included 544 TKAs, 8 (1.47%) of which presented PPI, and the patients had an average age at presentation of 66 years ( 5.7 years) and an average body mass index (BMI) of 30.3 ( 4, 5) kg/m2 . The median time of presentation of the PPI was of 411 ( 1,034) days. The main comorbidities recorded were arterial hypertension in 5 (62.5%), smoking in 4 (50%) cases, and dyslipidemia in 4 (50%) cases. In total, 5 (62.5%) patients presented polymicrobial etiology, and in 3 (37.5%), a single microorganism was isolated. The main isolated agents were Staphylococcus aureus and coagulasenegative Staphylococcus, both multidrug-resistant, in 6 (75%) and 3 (37.5%) patients respectively. All patients received three doses of cefazolin as surgical prophylaxis. A sensitivity of 100% to vancomycin and rifampicin (12/12 cultures), and a resistance of 83.4% to ciprofloxacin (4/9 cultures) were described. Overall, 2 (25%) patients died 3 years after the TKA, due to causes unrelated to PPI. There were no cases of infectious relapse after the review. CONCLUSION An incidence of 1.47% (8 cases) of PPI was found. All patients with PPI presented some presurgical comorbidity. The main microbiological agents identified were multidrug-resistant and susceptible to vancomycin and rifampicin

Nasal microbiota evolution within the congregate setting imposed by military training.

The human microbiome is comprised of a complex and diverse community of organisms that is subject to dynamic changes over time. As such, cross-sectional studies of the microbiome provide a multitude of information for a specific body site at a particular time, but they fail to account for temporal changes in microbial constituents resulting from various factors. To address this shortcoming, longitudinal research studies of the human microbiome investigate the influence of various factors on the microbiome of individuals within a group or community setting. These studies are vital to address the effects of host and/or environmental factors on microbiome composition as well as the potential contribution of microbiome members during the course of an infection. The relationship between microbial constituents and disease development has been previously explored for skin and soft tissue infections (SSTIs) within congregate military trainees. Accordingly, approximately 25% of the population carries Staphylococcus aureus within their nasal cavity, and these colonized individuals are known to be at increased risk for SSTIs. To examine the evolution of the nasal microbiota of U.S. Army Infantry trainees, individuals were sampled longitudinally from their arrival at Fort Benning, Georgia, until completion of their training 90 days later. These samples were then processed to determine S. aureus colonization status and to profile the nasal microbiota using 16S rRNA gene-based methods. Microbiota stability differed dramatically among the individual trainees; some subjects exhibited great stability, some subjects showed gradual temporal changes and some subjects displayed a dramatic shift in nasal microbiota composition. Further analysis utilizing the available trainee metadata suggests that the major drivers of nasal microbiota stability may be S. aureus colonization status and geographic origin of the trainees. Nasal microbiota evolution within the congregate setting imposed by military training is a complex process that appears to be affected by numerous factors. This finding may indicate that future campaigns to prevent S. aureus colonization and future SSTIs among high-risk military trainees may require a 'personalized' approach.

Portación nasal de Staphylococcus aureus en el personal de salud de áreas críticas de un Hospital Pediátrico durante julio-setiembre 2018 / Nasal carriage of Staphylococcus aureus in health personnel in critical areas of a Pediatric Hospital during July-September 2018 / Transporte nasal de Staphylococcus aureus em profissionais de saúde em áreas críticas de um Hospital Pediátrico durante julho-setembro de 2018

Las infecciones intrahospitalarias (IIH) son causa de elevada morbimortalidad y representan un problema sanitario importante. El personal de salud es reservorio y potencial transmisor de los agentes etiológicos de las mismas. S. aureus es uno de los microorganismos implicados, por lo tanto es importante conocer la frecuencia de portación en el personal de salud y establecer el perfil de susceptibilidad antimicrobiana para contribuir con la elaboración de medidas de prevención incluyendo actividades educativas. Objetivo: Conocer la frecuencia de portación de S. aureus, distribución y antibiotipos de las cepas presentes en el personal sanitario del Hospital Pediátrico de Referencia (HPR). Materiales y métodos: Se realizó un estudio descriptivo durante el periodo julio-setiembre del año 2018. Se incluyeron muestras de hisopados nasales de trabajadores de la salud de distintas áreas de internación que consintieron participar en el estudio. Se excluyeron aquellos que recibieron antibióticos dentro de los 3 meses previos al estudio. Las muestras fueron sembradas en agar sangre ovina al 5% (ASO) y se incubaron a 35-37ºC en aerobiosis por 24-48 horas. La identificación de las colonias sospechosas de Staphylococcus aureus por métodos convencionales y MALDI-TOF. El patrón de resistencia antimicrobiana de S. aureus se detectó por disco-difusión. En los cultivos resistentes a meticilina (SAMR) se determinó la presencia del gen mecA y se realizó la tipificación del SCCmec por pruebas de reacción en cadena de polimerasa. Resultados: Se obtuvieron 225 hisopados a partir de 225 trabajadores, presentaron desarrollo 212. En 49 se recuperaron cultivos de S. aureus. Correspondieron a SAMR 11 de las 49 cepas, todas portaban el gen mecA. Hubo predominio en el personal de enfermería (7/11), en los servicios de hemato-oncología (3/11) y cuidados intensivos neonatales (4/11). Asociaron resistencia a macrólidos y clindamicina 8 de 11 aislamientos SAMR, a gentamicina 2 y a mupirocina uno. El SCCmec más frecuentemente identificado fue el tipo IV (7/11). Conclusiones: Los resultados muestran la presencia de cepas SAMR entre el personal de salud del CHPR y aportan información complementaria para efectuar prevención y control de las IIH, actuando sobre todo en el personal de salud encargado de la atención de pacientes susceptibles.

Hospital-acquired infections (IIH) are a cause of high morbidity and mortality and represent a major health problem. Health personnel are reservoirs and potential transmitters of their etiological agents. S. aureus is one of the microorganisms involved, therefore it is important to know the frequency of carriage in health personnel and establish the antimicrobial susceptibility profile to contribute to the development of prevention measures, including educational activities. Objective: To know the frequency of carriage of S. aureus, distribution and antibiotypes of the strains present in the health personnel of the Reference Pediatric Hospital (HPR). Materials and methods: A descriptive study was carried out during the period July-September 2018. Nasal swab samples from health workers from different hospitalization areas who agreed to participate in the study were included. Those who received antibiotics within 3 months prior to the study were excluded. The samples were seeded in 5% sheep blood agar (ASO) and incubated at 35-37ºC in aerobiosis for 24-48 hours. Identification of suspicious Staphylococcus aureus colonies by conventional methods and MALDI-TOF. The antimicrobial resistance pattern of S. aureus was detected by disc diffusion. In methicillin-resistant cultures (MRSA), the presence of the mecA gene was determined and SCCmec was typified by polymerase chain reaction tests. Results: 225 swabs were obtained from 225 workers, 212 showed development. S. aureus cultures were recovered from 49. 11 of the 49 strains corresponded to MRSA, all of them carried the mecA gene. There was a predominance in the nursing staff (7/11), in the hematology-oncology services (3/11) and neonatal intensive care (4/11). They associated resistance to macrolides and clindamycin in 8 of 11 MRSA isolates, 2 to gentamicin, and 1 to mupirocin. The most frequently identified SCCmec was type IV (7/11). Conclusions: The results show the presence of MRSA strains among the health personnel of the CHPR and provide complementary information to carry out prevention and control of IIH, acting especially on the health personnel in charge of the care of susceptible patients.

As infecções hospitalares (HII) são causa de alta morbidade e mortalidade e representam um importante problema de saúde. Os profissionais de saúde são reservatórios e potenciais transmissores de seus agentes etiológicos. O S. aureus é um dos micro-organismos envolvidos, por isso é importante conhecer a frequência de portadores em profissionais de saúde e estabelecer o perfil de suscetibilidade antimicrobiana para contribuir no desenvolvimento de medidas de prevenção incluindo atividades educativas. Objetivo: Conhecer a frequência de portadores de S. aureus, distribuição e antibiótipos das cepas presentes no pessoal de saúde do Hospital Pediátrico de Referência (HPR). Materiais e métodos: Foi realizado um estudo descritivo durante o período de julho a setembro de 2018. Foram incluídas amostras de swab nasal de profissionais de saúde de diferentes áreas de internação que concordaram em participar do estudo. Aqueles que receberam antibióticos nos 3 meses anteriores ao estudo foram excluídos. As amostras foram semeadas em 5% de ágar sangue de carneiro (ASO) e incubadas a 35-37ºC em aerobiose por 24-48 horas. Identificação de colônias suspeitas de Staphylococcus aureus por métodos convencionais e MALDI-TOF. O padrão de resistência antimicrobiana de S. aureus foi detectado por difusão em disco. Em culturas resistentes à meticilina (MRSA), a presença do gene mecA foi determinada e SCCmec foi tipificado por testes de reação em cadeia da polimerase. Resultados: 225 swabs foram obtidos de 225 trabalhadores, 212 apresentaram desenvolvimento. Culturas de S. aureus foram recuperadas de 49. 11 das 49 cepas correspondiam a MRSA, todas carregavam o gene mecA. Houve predominância na equipe de enfermagem (7/11), nos serviços de hematologia-oncologia (3/11) e de terapia intensiva neonatal (4/11). Eles associaram resistência a macrolídeos e clindamicina em 8 de 11 isolados de MRSA, 2 à gentamicina e 1 à mupirocina. O SCCmec mais frequentemente identificado foi o tipo IV (7/11). Conclusões: Os resultados mostram a presença de cepas de MRSA entre os profissionais de saúde do CHPR e fornecem informações complementares para realizar a prevenção e controle da HII, atuando principalmente sobre os profissionais de saúde responsáveis ​​pelo atendimento de pacientes suscetíveis.

Distribution of staphylococcal and mammaliicoccal species from compost-bedded pack or sand-bedded freestall dairy farms.

The purpose of this prospective observational study was to determine whether dairy cattle housing types were associated with staphylococcal and mammaliicoccal populations found on teat skin, bedding, and in bulk tank milk. Twenty herds (n = 10 sand-bedded freestall herds; n = 10 compost-bedded pack herds) were enrolled. Each herd was visited twice for sample collection, and at each visit, 5 niches were sampled, including bulk tank milk, composite teat skin swab samples collected before premilking teat preparation, composite teat skin swab samples collected after premilking teat preparation, unused fresh bedding, and used bedding. All samples were plated on Mannitol salt agar and Columbia blood agar and staphylococcal-like colonies were selected for further evaluation. Bacterial colonies were speciated using MALDI-TOF mass spectrometry. All species were grouped into 4 categories included host-adapted, opportunistic, environmental, and unclassified. Absolute numbers and proportions of each genus and species were calculated. Proportional data were compared between groups using Fisher's exact test. Data representing 471 staphylococcal-like organisms were analyzed. Overall, 27 different staphylococcal and mammaliicoccal species were identified. Staphylococcus chromogenes was the only species identified from all 20 farms. A total of 20 different staphylococcal-like species were identified from bulk tank milk samples with the most prevalent species being S. chromogenes, followed by Staphylococcus aureus and Mammaliicoccus sciuri. Overall, more staphylococcal and mammaliicoccal isolates were identified among used bedding than unused bedding. The increased numbers of isolates within used bedding were primarily from used sand bedding samples, with 79% (76/96) of used bedding isolates being identified from sand bedding and only 20.8% (20/96) from used compost-bedded pack samples. When comparing categories found among sample types, more unclassified species were found in used sand bedding than in used compost-bedded pack samples. This finding is possibly related to the composting temperatures resulting in reduced growth or destruction of bacterial species. The prevalence of S. aureus was high in bulk tank milk for all herds, regardless of herd type, which may represent the influence of unmeasured management factors. Overall, staphylococcal and mammaliicoccal species were highly prevalent among samples from both farm types.

Thymol Reduces agr-Mediated Virulence Factor Phenol-Soluble Modulin Production in Staphylococcus aureus.

Staphylococcus aureus is a major human bacterial pathogen that carries a large number of virulence factors. Many virulence factors of S. aureus are regulated by the accessory gene regulator (agr) quorum-sensing system. Phenol-soluble modulins (PSMs) are one of the agr-mediated virulence determinants known to play a significant role in S. aureus pathogenesis. In the present study, the efficacy of thymol to inhibit PSM production including δ-toxin in S. aureus was explored. We employed liquid chromatography-mass spectrometry (LC-MS) to quantify the PSMsα1-PSMα4, PSMß1 and PSMß2, and δ-toxin production from culture supernatants. We found that thymol at 0.5 MIC (128 µg/mL) significantly reduced the PSMα and δ-toxin production in S. aureus WKZ-1, WKZ-2, LAC USA300, and ATCC29213. Downregulation in transcription by quantitative real-time (qRT) PCR analysis of response regulator agrA and receptor histidine kinase agrC upon 0.5 MIC thymol treatment affirmed the results of LC-MS quantification of PSMs. In silico molecular docking analysis demonstrated the binding affinity of thymol with receptors AgrA and AgrC. Transmission electron microscopy images revealed no ultrastructural alterations (cell wall and membrane) in thymol-treated WKZ-1 and WKZ-2 S. aureus strains. Here, we demonstrated that thymol reduces various PSM production in S. aureus clinical isolates and reference strains with mass spectrometry.

Sacroileítis infecciosa secundaria a un absceso del iliopsoas ­ reporte de un caso / Infectious sacroiliitis secondary to an iliopsoas abscess ­ a case report

La sacroileítis infecciosa (SII), también descrita en la literatura como sacroileítis séptica o piógena, es una patología infrecuente, y su diagnóstico constituye un reto debido a su rareza relativa y la diversa presentación clínica, que frecuentemente imita otros trastornos más prevalentes originados en estructuras vecinas. Se requiere un alto índice de sospecha y un examen físico acucioso para un diagnóstico oportuno, mientras que los estudios de laboratorio y de imagen ayudan a confirmar el diagnóstico y dirigir la estrategia de tratamiento apropiada para evitar complicaciones y secuelas a corto y mediano plazos. Presentamos un caso de paciente de género femenino de 36 años, con cuadro clínico de SII izquierda, secundaria a un absceso del músculo iliopsoas, condición que generalmente se presenta como una complicación de la infección. Se realizaron los diagnósticos clínico, imagenológico y Biológico, se inició el tratamiento antibiótico oportuno, y se logró una excelente evolución clínica, sin secuelas

Infectious sacroiliitis (ISI), also described in the literature as septic or pyogenic sacroiliitis, is an infrequent pathology, and its diagnosis constitutes a challenge due to its relative rarity and the diverse clinical presentation, frequently imitating other more prevalent disorders originating in neighboring structures. A high index of suspicion and a thorough physical examination are required in order to establish an opportune diagnosis, while laboratory and imaging studies help confirm the diagnosis and direct the appropriate treatment strategy to avoid complications and sequelae in the short and medium terms. We herein present a case of a female patient aged 36 years, with a clinical picture of left ISI, secondary to an iliopsoas muscle abscess, a condition that usually presents as a complication of the infection. The clinical, imaging and microbiological diagnoses were made, the timely antibiotic treatment was initiated, and an excellent clinical evolution without sequelae was achieved.

Irrigation and debridement for knee osteoarthritis patients with suspected infection by intra-articular injection before total knee arthroplasty: a retrospective study.

BACKGROUND: Patients suffer from knee osteoarthritis (KOA) pain may seek for intra-articular injections before total knee arthroplasty (TKA), which have a possibility of causing the joint sepsis. However, the management and clinical outcomes of these patients following TKA remain uncertain. METHODS: Patients with a history of intra-articular injection, in which a joint sepsis was suspected, were included. The patients received joint irrigation and debridement (I&D) and antibiotic treatment until serum inflammatory indicators returned to normal level before TKA. The information of joint fluid routine and culture, synovium section and culture, and serum inflammatory indicator values were collected. Range of motion, Knee Society Scores (KSS) and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) were used for functional evaluations. RESULTS: A total of 17 patients with 17 knee joints were included, all with elevated C-reactive protein (CRP) levels (23.5 ± 8.7 mg/L) as well as increased number of white blood cells (WBC) in the aspiration (50.8 ± 15.3) × 109/L, but no positive cultures were found. The culture of synovium detected three positive results: two Staphylococcus epidermidis and one S. aureus. I&D treatment had no obvious effect on the functional outcomes of KOA, but alleviated the joint pain (p < 0.01). Furthermore, we found that I&D pretreatment could increase the operation time with about 10 min longer than the primary TKA (p < 0.01). With respect to TKA outcomes, I&D had a slight influence on the knee flexion (p < 0.01), but no significant difference was identified between the two groups for KSS and WOMAC (all p values > 0.05). In addition, there was no significant difference in complication rates between the two groups in the last follow-up. CONCLUSION: I&D treatment is a valuable procedure for suspected knee infection, which has a higher incidence of detecting microorganisms while does not influence the functional outcomes and complication rates of TKA. However, further larger studies are required to confirm these findings.

Is methicillin-susceptible Staphylococcus aureus (MSSA) CC398 a true animal-independent pathogen?

OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) belonging to ST398 has been widely described in animals. In parallel, methicillin-susceptible (MSSA) ST398 isolates causing severe infections in humans have recently emerged as animal-independent pathogens. This study aimed at characterising MSSA CC398 from different animal species in France in comparison with MSSA CC398 genomes, mostly of human origin. METHODS: CC398 were detected by clone-specific PCR. Antimicrobial susceptibility testing was performed using the disk diffusion method. Whole genome sequencing (WGS) was performed on 47 MRSA and MSSA isolates, of which spa-types as well as resistance and virulence genes were extracted. A maximum likelihood phylogenetic tree based on SNPs was performed on all sequenced isolates and 51 additional MRSA and MSSA data found on publicly available databases. RESULTS: From 275 MSSA isolates studied, 28 (10.18%) belonged to the CC398 lineage (26 ST398 and two single-locus variants) and mainly originated from cats (n=12/44, 27.3%) and dogs (n=8/55, 14.6%). Five different spa-types were identified, t571 (n=18, 64.3%) and t1451 (n=5, 17.9%) being the most frequent ones. Out of the 28 MSSA isolates, 26 carried the scn gene, whereas 24 carried the erm(T) gene, and all were genetically similar to human isolates. CONCLUSION: This study challenges the current scientific opinion that human infections due to MSSA CC398 should only be considered an animal-independent issue.

Características clínicas y microbiológicas de infecciones de piel y partes blandas en pacientes pediátricos de dos hospitales de Buenos Aires / Skin and soft tissue infections in pediatrics

Las infecciones de piel y partes blandas (IPPB) en niños son una de las principales causas de prescripción de antimicrobianos. El objetivo del estudio fue describir las características clínicas y microbiológicas de las IPPB ambulatorias de niños asistidos en dos hospitales zonales. Se realizó un estudio prospectivo entre el 1/11/2017 y el 1/11/2018. Se incluyeron pacientes entre 1 mes y 15 años internados en dos hospitales. Se evaluó: edad, sexo, localidad, factores predisponentes, tipo de IPPB, muestras biológicas realizadas, aislamiento microbiológico, tratamiento empírico indicado y evolución del cuadro. Se realizó antibiograma y determinación genética. Se calculó chi2, IC95, OR; α=5%. N= 94. 58,7% masculinos. 12 pacientes <1 año, 85 >1 año (promedio de edad 4 años, 1-15). El 36% de Tandil y 63,8% de Florencio Varela. El 59,6% corresponden a IPPB purulentas. Se aislaron microorganismos en un 59,6%. Los aislamientos principales: SAMR (40,4%), SAMS (7,4%), S. agalactiae (2,1%) y S. pyogenes (2,1%). El 100% de SAMR son portadores de gen mecA y SCCmec tipo IV, sin multirresistencia. No hubo diferencia estadística entre los factores de riesgo evaluados para el desarrollo de IPPB por SAMR. El 52,1% de los niños recibió tratamiento antibiótico combinado, siendo la más indicada TMS-SMX + CLI en 36 eventos. (38,3%). La evolución fue favorable: no hubo diferencia significativa entre el subgrupo que se aisló SAMR y el que no se aisló SAMR; 91,9% (34/37) y 92,6% (50/54) correspondientemente (chi2: 0,01; p= 0,97 IC95: 0,26-3,88). El principal agente etiológico fue SAMRco, debiendo adecuar los tratamientos a este microorganismo.

Skin and soft tissue infections (SSIs) in children are one of the main causes of antimicrobial prescription. The aim of the study was to describe the clinical and microbiological characteristics of outpatient SSIs in children attended in two hospitals. A prospective study was conducted between 11/1/2017 and 11/1/2018. Patients between 1 month and 15 years old, hospitalized were included. We evaluated: age, sex, locality, predisposing factors, type of IPPB, biological samples taken, microbiological isolation, empirical treatment indicated and evolution of the condition. An antibiogram and genetic determination were performed. Chi2, CI95, OR; α=5% were calculated. N= 94. 58.7% male. 12 patients <1 year, 85 >1 year (mean age 4 years, 1-15). 36% were from Tandil and 63.8% from Florencio Varela. 59.6% corresponded to purulent SSIs. The diagnostic yield was 59.6%. Main isolates: MRSA (40.4%), MSSA (7.4%), S. agalactiae (2.1%) and S. pyogenes (2.1%). 100% of MRSA carried the mecA gene and SCCmec type IV, with no multidrug resistance. There was no statistical difference between the risk factors evaluated. 52.1% of children received combined antibiotic treatment, the most indicated being TMS-SMX + CLI in 36 events. (38,3%). Evolution was favorable: there was no significant difference between the subgroup that isolated MRSA and the subgroup that did not isolate MRSA; 91.9% (34/37) and 92.6% (50/54) respectively (chi2: 0.01; p= 0.97 CI95: 0.26-3.88). The main etiological agent was MRSA, and treatments should be adapted to this microorganism

Electrochemical nanobiosensors equipped with peptides: a review.

Recent research in the field of electrochemical biosensors equipped with peptides and nanomaterials have been categorized, reviewed, and critically analyzed. Indeed, using these innovative biosensors can revolutionize biomedical diagnostics in the future. Saving lives, time, and money in this field will be considered as some main benefits of this type of diagnosis. Here, these biosensors have been categorized and evaluated in four main sections. In the first section, the focus is on investigating the types of electrochemical peptide-based nanobiosensors applied to detect pathogenic microorganisms, microbial toxins, and viruses. In the second section, due to the importance of rapid diagnosis and prognosis of various cancers, the electrochemical peptide-based nanobiosensors designed to detect cancer biomarkers have been reviewed and analyzed. In the third section, the electrochemical peptide-based nanobiosensors, which were applied to detect the essential and effective biomolecules in the various diseases, and health control, including enzymes, hormones, biomarkers, and other biomolecules, have been considered. Finally, using a comprehensive analysis, all the used elements in these biosensors have been presented as conceptual diagrams that can effectively guide researchers in future developments. The essential factors in evaluating and analyzing these electrochemical peptide-based nanobiosensors such as analyte, peptide sequence, functional groups interacted between the peptide sequences and other biosensing components, the applied nanomaterials, diagnostic techniques, detection range, and limit of detection have also been included. Other analyzable items such as the type of used redox marker and the location of the peptide sequence against the signal transducer were also considered.

Comparison of Automated Ribotyping, spa Typing, and MLST in 108 Clinical Isolates of Staphylococcus aureus from Orthopedic Infections.

108 isolates of Staphylococcus aureus, belonging to six large ribogroups according to the automated Ribo-Printer® system, were studied with two highly used molecular methods for epidemiological studies, namely multi-locus sequence typing (MLST) and spa typing, followed by BURP and eBURST v3 analysis for clustering spa types and sequence (ST) types. The aim was to evaluate whether automated ribotyping could be considered a useful screening tool for identifying S. aureus genetic lineages with respect to spa typing and MLST. Clarifying the relationship of riboprinting with these typing methods and establishing whether ribogroups fit single clonal complexes were two main objectives. Further information on the genetic profile of the isolates was obtained from agr typing and the search for the mecA, tst genes, and the IS256 insertion sequence. Automated ribotyping has been shown to predict spa clonal complexes and MLST clonal complexes. The high cost and lower discriminatory power of automated ribotyping compared to spa and MSLT typing could be an obstacle to fine genotyping analyzes, especially when high discriminatory power is required. On the other hand, numerous advantages such as automation, ease and speed of execution, stability, typeability and reproducibility make ribotyping a reliable method to be juxtaposed to gold standard methods.