Methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus produce antimicrobial substances against members of the skin microbiota in children with atopic dermatitis.

Coagulase-negative Staphylococcus (CoNS) species inhibiting Staphylococcus aureus has been described in the skin of atopic dermatitis (AD) patients. This study evaluated whether Staphylococcus spp. from the skin and nares of AD and non-AD children produced antimicrobial substances (AMS). AMS production was screened by an overlay method and tested against NaOH, proteases and 30 indicator strains. Clonality was assessed by pulsed-field gel electrophoresis. Proteinaceous AMS-producers were investigated for autoimmunity by the overlay method and presence of bacteriocin genes by polymerase chain reaction. Two AMS-producers had their genome screened for AMS genes. A methicillin-resistant S. aureus (MRSA) produced proteinaceous AMS that inhibited 51.7% of the staphylococcal indicator strains, and it was active against 60% of the colonies selected from the AD child where it was isolated. On the other hand, 57 (8.8%) CoNS from the nares and skin of AD and non-AD children, most of them S. epidermidis (45.6%), reduced the growth of S. aureus and other CoNS species. Bacteriocin-related genes were detected in the genomes of AMS-producers. AMS production by CoNS inhibited S. aureus and other skin microbiota species from children with AD. Furthermore, an MRSA colonizing a child with AD produced AMS, reinforcing its contribution to dysbiosis and disease severity.

Staphylococcus capitis Bloodstream Isolates: Investigation of Clonal Relationship, Resistance Profile, Virulence and Biofilm Formation.

Staphylococcus capitis has been recognized as a relevant opportunistic pathogen, particularly its persistence in neonatal ICUs around the world. Therefore, the aim of this study was to describe the epidemiological profile of clinical isolates of S. capitis and to characterize the factors involved in the persistence and pathogenesis of these strains isolated from blood cultures collected in a hospital in the interior of the state of São Paulo, Brazil. A total of 141 S. capitis strains were submitted to detection of the mecA gene and SCCmec typing by multiplex PCR. Genes involved in biofilm production and genes encoding enterotoxins and hemolysins were detected by conventional PCR. Biofilm formation was evaluated by the polystyrene plate adherence test and phenotypic resistance was investigated by the disk diffusion method. Finally, pulsed-field gel electrophoresis (PFGE) was used to analyze the clonal relationship between isolates. The mecA gene was detected in 99 (70.2%) isolates, with this percentage reaching 100% in the neonatal ICU. SCCmec type III was the most prevalent type, detected in 31 (31.3%) isolates and co-occurrence of SCCmec was also observed. In vitro biofilm formation was detected in 46 (32.6%) isolates but was not correlated with the presence of the ica operon genes. Furthermore, biofilm production in ICU isolates was favored by hyperosmotic conditions, which are common in ICUs because of the frequent parenteral nutrition. Analysis of the clonal relationship between the isolates investigated in the present study confirms a homogeneous profile of S. capitis and the persistence of clones that are prevalent in the neonatal ICU and disseminated across the hospital. This study highlights the adaptation of isolates to specific hospital environments and their high clonality.

Methicillin-Resistant Staphylococcus aureus and Coagulase-Negative Staphylococcus from School Dining Rooms in Argentina.

Methicillin-resistant Staphylococcus aureus (MRSA) constitutes an important cause for concern in the field of public health, and the role of the food chain in the transmission of this pathogen and in antimicrobial resistance (AMR) has not yet been defined. The objectives of this work were to isolate and characterize coagulase-positive Staphylococcus (CoPS) and coagulase-negative Staphylococcus (CoNS), particularly S. aureus, from school dining rooms located in Argentina. From 95 samples that were obtained from handlers, inert surfaces, food, and air in 10 establishments, 30 Staphylococcus strains were isolated. Four isolates were S. aureus, and the remaining ones (N = 26) belonged to 11 coagulase-negative species (CoNS). The isolates were tested for susceptibility to nine antibiotics. The presence of genes encoding toxins (luk-PV, sea, seb, sec, sed, and see), adhesins (icaA, icaD), and genes that confer resistance to methicillin (mecA) and vancomycin (vanA) was investigated. The resistance rates measured for penicillin, cefoxitin, gentamicin, vancomycin, erythromycin, clindamycin, levofloxacin, trimethoprim-sulfamethoxazole, and tetracycline were 73%, 30%, 13%, 3%, 33%, 17%, 13%, 7%, and 7% of the isolates, respectively. Seventeen AMR profiles were detected, and 11 isolates were multidrug resistant (MDR). Seven methicillin-resistant Staphylococcus isolates were detected in the hands of handlers from four establishments, two of them were MRSA. Two S. aureus isolates presented icaA and icaD, another one, only icaD. The gene vanA was found in two isolates. In relation to S. aureus, resistance to vancomycin but not to gentamicin was detected. School feeding plays a key role in the nutrition of children, and the consumption of food contaminated with MRSA and vancomycin-resistant S. aureus (VRSA) can be a serious threat to health. In particular, it was detected that the handlers were the source of MRSA, VRSA, MR-CoNS (methicillin-resistant coagulase-negative Staphylococcus), and MDR isolates. The results obtained indicate that the vigilance of this pathogen in school dining rooms should be extreme.

Effects of lactic acid bacteria and coagulase-negative staphylococci on dry-fermented sausage quality and safety: Systematic review and meta-analysis.

The meta-analysis aim was to confirm and quantifying the influence of starter cultures on microbiological and physical-chemical parameters of dry-fermented sausages at the end fermentation stage. The literature search yielded 1194 citations, and 77 studies with 178 experiments were eligible and included in the meta-analysis, a random-effects model was used to estimate the pooled weighted mean difference (MD) with 95% confidence interval (CI).The use of starter culture in dry-fermented sausages significantly reduced pH (MD: -0.364; CI: -0.414; -0.319), moisture (MD: -1.443; CI: -1.931; -0.955), aw (MD: -0.011; CI: -0.017; -0.006), Enterobacteriaceae count (MD: -1.119; CI: -1.293; -0.945), yeasts and molds count (MD: -0.351; CI: -0.691; -0.084), and increased color component a* (MD: 0.859; CI: 0.266;1.452), color component L* (MD: 1.288; CI: 0.433; 2.143), LAB count (MD: 0.981; CI: 0.696;1.267), Staphylococci count (MD: 0.484; CI: 0.293; 0.675) and TVC (MD: 0.529; CI: 0.098; 0.959). The results of the sub-analysis suggest that the addition of LAB and LAB/CNS inocula have a greater effect on the physico-chemical and microbiological parameters studied in this work. In the meta-regression analysis, a positive linear relationship was found in starter culture sausages in comparison with control batch between LAB count and the dose of starter culture added, and in the pH and Enterobacteriaceae count with the passage of fermentation days. In contrast, a negative linear relationship was found between redness and increased casing diameter of the sausages. Therefore, our work shows impact that addition of starter cultures has on safety and quality of dry-fermented sausages.

Unusual carriage of virulence genes sasX/sesI/shsA by nosocomial Staphylococcus haemolyticus from Brazil.

Background: Staphylococcus haemolyticus is an emerging threat in the nosocomial environment but only some virulence factors are known. Materials & methods: The frequency of the sasX gene (or orthologues sesI/shsA), encoding an invasiveness-related surface-associated protein, in S. haemolyticus was detected in different hospitals in Rio de Janeiro. Results: 9.4% of strains were sasX/sesI/shsA-positive, some were in the context of the ΦSPß-like prophage and devoid of CRISPR systems, indicating potential transferability of their virulence genes. Gene sequencing evidenced that Brazilian S. haemolyticus harbored sesI, instead of the usual sasX, while S. epidermidis had sasX instead of sesI, suggesting horizontal acquisition. Conclusion: The contexts of Brazilian sasX/sesI/shsA favor transfer, which is alarming given the difficulty in treating infections caused by S. haemolyticus.

Biofilm-forming microorganisms causing hospital-acquired infections from intravenous catheter: A systematic review.

The high prevalence of nosocomial infections is related to the use of medical insertion devices such as central venous catheters (CVCs). Most of the microorganisms causing nosocomial infections are biofilm producers, this characteristic allows them to adhere to abiotic surfaces and cause initial catheter infections that can lead to bloodstream infections. Our main goal in this systematic review was to evaluate the prevalence of biofilm among CVC-related infections, particularly among Intensive Care Unit (ICU) patients, in the studies applying different in vitro and in vivo methodologies. All studies reporting clinical isolates from patients with catheter-related nosocomial infections and biofilm evaluation published up to 24 June 2022 in the PubMed and Scopus databases were included. Twenty-five studies met the eligibility criteria and were included in this systematic review for analysis. Different methodologies were applied in the assessment of biofilm-forming microorganisms including in vitro assays, catheter-infected in vitro, and in vivo mouse models. The present study showed that between 59 and 100% of clinical isolates were able to form biofilms, and the prevalence rate of biofilm formation varied significantly between studies from different countries and regions. Among the clinical isolates collected in our study set, a wide variety of microorganisms including Gram-positive strains, Gram-negative strains, and Candida albicans were found. Many authors studied resistance mechanisms and genes related to biofilm development and surface adherence properties. In some cases, the studies also evaluated biofilm inhibition assays using various kinds of catheter coatings.

Comparative Phenotypic and Genomic Features of Staphylococci from Sonication Fluid of Orthopedic Implant-Associated Infections with Poor Outcome.

Staphylococcus spp. remain the leading biofilm-forming agents causing orthopedic implant-associated infections (OIAI). This is a descriptive study of phenotypic and genomic features identified in clinical isolates of S. aureus and coagulase-negative Staphylococcus (CoNS) recovered from OIAIs patients that progressed to treatment failure. Ten isolates were identified by matrix-time-of-flight laser-assisted desorption mass spectrometry (MALDI-TOF-MS) and tested for antibiotic susceptibility and biofilm formation. Genotypic characteristics, including, MLST (Multi Locus Sequence Typing), SCCmec typing, virulence and resistance genes were assessed by whole-genome sequencing (WGS). All S. aureus harbored mecA, blaZ, and multiple resistance genes for aminoglycosides and quinolones. All MRSA were strong biofilm producers harboring the complete icaADBC and icaR operon. Seven CoNS isolates comprising five species (S. epidermidis, S. haemolyticus, S. sciuri, S. capitis and S. lugdunensis) were analyzed, with mecA gene detected in five isolates. S. haemolitycus (isolate 95), and S. lugdunensis were unable to form biofilm and did not harbor the complete icaADBCR operon. High variability of adhesion genes was detected, with atl, ebp, icaADBC operon, and IS256 being the most common. In conclusion, MRSA and CoNS isolates carrying genes for biofilm production, and resistance to ß-lactam and aminoglycosides are associated with treatment failure in OIAIs.

Infección por Staphylococcus lugdunensis: descripción de 44 casos / Staphylococcus lugdunensis infection: report of 44 cases

INTRODUCCIÓN: Staphylococcus lugdunensis, es un estafilococo coagulasa negativa (SCN) con características de virulencia y de sensibilidad antimicrobiana que lo hacen más parecido a Staphylococcus aureus que a otros SCN. OBJETIVOS: Conocer las características clínicomicrobiológicas de los aislados de S. lugdunensis identificados en nuestra institución. MATERIAL Y MÉTODOS: Se realizó un estudio retrospectivo de los aislados de S. lugdunensis entre los años 2017 y 2019 en el Servicio de Microbiología del Hospital Universitario San Jorge de Huesca (España). Se revisaron las historias clínicas correspondientes a los pacientes con aislamiento de S. lugdunensis, considerándose las siguientes variables: edad, sexo, tipo de muestra, servicio de procedencia y enfermedad de base. La identificación bacteriana se realizó con MALDI-TOF VITEK MS (BioMérieux, Francia). Así mismo, se estudió su patrón de susceptibilidad antimicrobiana in vitro mediante microdilución en placa. RESULTADOS: Se obtuvieron 44 aislados de S. lugdunensis: 12 procedían de heridas, 10 fueron abscesos, 8 úlceras, 7 orinas, 4 frotis cutáneos, 2 exudados óticos, y 1 exudado vaginal. En relación con la enfermedad de base destacaron cinco pacientes con procesos tumorales y diez con diabetes mellitus. En 17 pacientes existían antecedentes de cirugía o traumatismo reciente. La mayoría de las cepas fueron sensibles a los antimicrobianos estudiados. En 19 de ellas se observó producción de β-lactamasa, dos fueron resistentes a macrólidos y tres a clindamicina. Todas las cepas fueron sensibles a oxacilina, gentamicina y cotrimoxazol. CONCLUSIONES: Aunque S. lugdunensis mantiene una buena sensibilidad a la mayoría de los antimicrobianos, su tendencia a producir abscesos y que exprese factores de virulencia más parecido a S. aureus que a otros SCN, hace necesaria una correcta identificación en el laboratorio con el fin de que su incidencia no quede subestimada.

BACKGROUND: Staphylococcus lugdunensis is a coagulase-negative staphylococcus (CNS) with virulence and antibiotic sensitivity characteristics which makes it more similar to Staphylococcus aureus than other CNS. AIM: To know the microbiological and clinical characteristics of S. lugdunensis isolates identified from our health sector. METHODS: A retrospective study of S. lugdunensis isolates was carried out between 2017 and 2019 in the Microbiology Service of the San Jorge University Hospital in Huesca (Spain). The clinical records of patients with S. lugdunensis isolation were reviewed, considering the following factors: age, sex, sample type, service and underlying disease. Bacterial identification was performed using MALDI-TOF VITEK MS (BioMérieux, France). The pattern of antibiotic susceptibility was studied by means of plate microdilution. RESULTS: 44 isolates of S. lugdunensis were obtained: 12 corresponded to wounds, 10 were abscesses, 8 ulcers, 7 urine samples, 4 skin smears, 2 otic exudates, and 1 vaginal exudate. Regarding the underlying disease, five patients had a tumor processes and ten had diabetes mellitus. In 17 patients there was a history of recent surgery or trauma. Most of the strains were susceptible to the antibiotics studied. Production of beta-lactamase was observed in 19 of them, two were resistant to macrolides and three to clindamycin. None of the isolates were resistant to oxacillin, gentamicin or cotrimoxazole. CONCLUSIONS: Although S. lugdunensis maintains a good sensitivity to most antibiotics, its tendency to produce abscesses and that it expresses virulence factors more similar to S. aureus than to other CNS requires a correct identification in the laboratory so that its incidence is not underestimated.

Evidence of cross-contamination of waste workers and transmission of antimicrobial resistance genes by coagulase-negative Staphylococcus isolated from dental solid waste: an intriguing study.

The aim of this study was to phenotypically and genotypically identify coagulase-negative Staphylococcus (CoNS) recovered from the nostrils of waste workers and from dental waste; 135 strains were recovered and S. epidermidis was the prevailing species. Genetic similarity (100%) was observed between the two S. epidermidis isolated from different employees on the same shift and 85% similarity between the S. epidermidis recovered from an employee's nostril and from waste. The mecA gene was found in 20 CoNS, and 20% were also found to possess the vanA gene. The blaZ gene was detected in 46.7%, and the icaA (34.8%), B and C genes (11.8% each). Our findings emphasized the biological risk to which waste workers are exposed and unprecedently confirms that it was possible to recover genetically identical bacterial species from waste and from workers' nostrils. It is important to highlight that this risk is raised by the detection of relevant antimicrobial resistance genes. The results also suggest that effective measures to correctly manage waste and promote the rational use of antimicrobials should be adopted.

Isolation and antimicrobial resistance of coagulase-negative staphylococci recovered from healthy tortoises in Minas Gerais, Brazil / Isolamento e resistência aos antimicrobianos de estafilococos coagulase negativos recuperados de jabutis saudáveis em Minas Gerais, Brasil

In the last few decades, there has been a global increase in the adoption of reptiles as companion animals, mainly turtles and tortoises. Considering the popularity of reptiles as pets in Brazil, and a notable lack of data about potentially pathogenic staphylococci in these animals, this study isolated and evaluate the antimicrobial susceptibility of staphylococcal species from healthy tortoises (Chelonoidis carbonaria) in Brazil. During a 12-month period (February 2019 to February 2020), cloacal swabs from 66 healthy tortoises were collected at the Wild Animals Screening Center in Belo Horizonte, Minas Gerais, Brazil. The swabs were plated onto mannitol salt agar for staphylococci isolation, and species identification was performed using MALDI-TOF MS. Antimicrobial susceptibility was investigated using the disk diffusion method, and the presence of the mecA gene was investigated by PCR to detect methicillin resistance. Of the tested animals, 72.7% were positive for staphylococcal isolation. All isolates were coagulase-negative staphylococci (CoNS), and Staphylococcus sciuri (81.3%), and S. xylosus (12.5%) were the most frequently isolated species. The majority of the isolates (56%) were resistant to at least one antimicrobial agent. A high frequency of resistance was observed for penicillin (35.5%) and tetracycline (29.1 %). All strains were susceptible to cefoxitin, chloramphenicol, ciprofloxacin, erythromycin, and gentamicin. All isolates were negative for the mecA gene. The present work suggests that healthy tortoises are mainly colonized by CoNS, especially S. sciuri. Half of the isolates were resistant to at least one antimicrobial, raising questions regarding the possible role of these animals as reservoirs of antimicrobial resistance genes.

Nas últimas décadas, houve um aumento global na adoção de répteis como animais de companhia, principalmente tartarugas e jabutis. Considerando a popularidade dos répteis como animais de estimação no Brasil e a notável falta de dados sobre estafilococos potencialmente patogênicos nesses animais, o objetivo deste estudo foi isolar e avaliar a susceptibilidade antimicrobiana de espécies estafilocócicas de jabutis (Chelonoidis carbonaria) saudáveis no Brasil. Durante um período de 12 meses (fevereiro de 2019 a fevereiro de 2020), suabes cloacais de 66 jabutis saudáveis foram coletados no Centro de Triagem de Animais Silvestres em Belo Horizonte, Minas Gerais, Brasil. Os suabes foram plaqueados em ágar manitol salgado para isolamento de estafilococos e a identificação das espécies foi realizada usando MALDI-TOF MS. A susceptibilidade aos antimicrobianos foi investigada pelo método de difusão em disco, e a presença do gene mecA foi investigada por PCR para detectar resistência à meticilina. Dos animais testados, 72,7% foram positivos para o isolamento estafilocócico. Todos os isolados eram estafilococos coagulase-negativos (CoNS), sendo Staphylococcus sciuri (81,3%) e S. xylosus (12,5%) as espécies mais frequentemente isoladas. A maioria dos isolados (56%) foi resistente a pelo menos um antimicrobiano. Alta frequência de resistência foi observada para penicilina (35,5%) e tetraciclina (29,1%). Todas as estirpes foram sensíveis à cefoxitina, cloranfenicol, ciprofloxacina, eritromicina e gentamicina. Todos os isolados foram negativos para o gene mecA. O presente trabalho sugere que jabutis saudáveis são colonizados principalmente por CoNS, especialmente S. sciuri. Metade dos isolados foram resistentes a pelo menos um antimicrobiano, levantando questões sobre o possível papel desses animais como reservatórios de genes de resistência aos antimicrobianos.

Infecciones intrahospitalarias por estafilococo coagulasa negativo en una unidad de neonatología / Coagulase negative streptococci nosocomial infections at a neonatal intensive care unit / Infecções intra-hospitalares por estafilococo coagulasa negativa numa unidade de neonatologia

Introducción: la sepsis tardía por estafilococo coagulasa negativo (SCoN) es una causa común de morbimortalidad en la unidad neonatal. Los SCoN son los microorganismos más frecuentemente involucrados con aproximadamente el 50% de los casos. El objetivo de este estudio es analizar la incidencia y las características de los neonatos portadores de sepsis tardía por SCoN. Materiales y métodos: se realizó un estudio descriptivo, longitudinal, retrospectivo. Se utilizaron las bases de datos del laboratorio de microbiología del hospital y las historias clínicas electrónicas para obtener la información. El período de estudio analizado fueron los años 2018 y 2019 en la unidad de cuidados intensivos e intermedios de recién nacidos del Centro Hospitalario Pereira Rossell. Resultados: obtuvimos una incidencia de 2,5% de los ingresos a cuidados intensivos e intermedios (25 pacientes). La edad gestacional al nacer fue de 28 semanas (25,0-35,0) y la mediana del peso fue de 1.070 g (730,0-2.365,0). La media de edad gestacional posmenstrual al momento del diagnóstico fue de 32,92±7,921 semanas. Por sospecha de sepsis precoz, 17 pacientes habían recibido un curso de antibióticos previo. El signo clínico más frecuentemente observado fue el deterioro del estado general, en 11 pacientes, seguido de distensión abdominal en 6 y fiebre en 5. Dentro de los SCoN, el más frecuentemente aislado fue el Staphylococcus epidermidis (13 pacientes); 22 pacientes recibieron tratamiento, 18 de ellos con vancomicina-meropenem y 4 con monoterapia con vancomicina. Conclusión: estos patógenos representan una causa importante de morbimortalidad en la unidad neonatal, particularmente en pacientes que presentan mayor gravedad y mayor necesidad de soporte vital. Se necesitan pautas claras de interpretación del rol de estos microorganismos y de abordaje de pacientes con riesgo de sepsis tardía, incluyendo el tratamiento antibiótico empírico.

Introduction: Coagulase Negative Staphylococci (CoNS) late onset sepsis is a common cause of morbidity and mortality in the neonatal intensive care unit (NICU). CoNS are the most frequently isolated microorganisms and total 50% of cases. The objective of this study is to analyze the incidence and characteristics of newborns carriers of late onset CoNS. Materials and methods: we performed a descriptive, retrospective, longitudinal study. Data was obtained from the hospital's microbiology laboratory database and electronic medical records. Patients included were those admitted to NICU during the period between 2018 and 2019. Results: we obtained an incidence of 2.5% of patients admitted to the NICU (25 patients). Median gestational age at birth was 28 weeks 25.0-35.0 and median birth weight was 1.070 g 730.0-2365.0. Mean gestational age at the time of diagnosis was 32.92±7.921 weeks. 17 patients had received an antibiotics course at birth because of early onset sepsis suspicion. The most frequently observed clinical symptom was deterioration of general condition, 11 patients, followed by abdominal distention in 6 and fever in 5. Among CoNS, the most frequently isolated pathogen was Staphylococcus epidermidis (13 patients). 22 patients received treatment, 18 a combination of vancomycin and meropenem and 4 received vancomycin monotherapy. Conclusion: these pathogens are a common cause of morbidity and mortality in the newborn intensive care unit, particularly in patients with more serious conditions and in those who require more advanced life support measures. Clearer interpretation of their role is needed as well as to determine a proper approach to patients at risk of late onset sepsis, including empiric antibiotic treatment.

Sepse tardia para Staphylococcus coagulase negativa (SCoN) é uma causa comum de morbidade e mortalidade na unidade neonatal. SCoNs são os microrganismos mais frequentemente envolvidos e representam aproximadamente 50% dos casos. O objetivo deste estudo é analisar a incidência e as características de neonatos com sepse tardia por SCoN. Materiais e métodos: foi realizado um estudo descritivo, longitudinal e retrospectivo. Usamos os bancos de dados do laboratório de microbiologia e prontuários médicos eletrônicos de nosso hospital para obter as informações. O período de estudo analisado foi de 2018 e 2019 na unidade de terapia intensiva e intermediária para recém-nascidos do Centro Hospitalar Pereira Rossell. Resultados: obtivemos uma incidência de 2,5% de internações em Terapia Intensiva e Intermediária (25 pacientes). A idade gestacional ao nascer foi de 28 semanas 25,0-35,0 e o peso médio foi de 1070g 730,0-2365,0. A média da idade gestacional pós-menstrual no momento do diagnóstico foi de 32,92 ± 7,921 semanas. 17 pacientes haviam recebido um curso anterior de antibióticos por suspeita de sepse precoce. O sinal clínico mais frequentemente observado foi deterioração do estado geral em 11 pacientes, seguido por distensão abdominal em 6 e febre em 5. Dentre os SCoN, o mais isolado foi o Staphylococcus Epidermidis (13 pacientes). 22 pacientes receberam tratamento, 18 deles com Vancomicina-Meropenem e 4 com Vancomicina em monoterapia. Conclusão: esses patógenos representam uma importante causa de morbimortalidade na unidade neonatal, principalmente em pacientes com maior gravidade e maior necessidade de suporte de vida. Orientações claras são necessárias para interpretar o papel desses microrganismos e para abordar pacientes com risco de sepse tardia, incluindo tratamento com antibióticos.

PK/PD Analysis by Nonlinear Mixed-Effects Modeling of a Marbofloxacin Dose Regimen for Treatment of Goat Mastitis Produced by Coagulase-Negative Staphylococci.

Coagulase-negative staphylococci are main pathogens that produce goat mastitis. Marbofloxacin is a third-generation fluoroquinolone approved for treat mastitis in animals. The objectives of this study were: (i) to determine the pharmacokinetics of marbofloxacin (10 mg/kg/24 h) in serum and milk administered intramuscularly for five days in goats with mastitis induced by coagulase-negative staphylococci; (ii) to characterize the concentration-effect relationship of marbofloxacin against coagulase-negative staphylococci in Mueller Hinton broth and goat milk; (iii) to determine AUC/MIC cutoff values of marbofloxacin, and (iv) to perform a PK/PD analysis to evaluate the efficacy of the dose regimen for the treatment of goat mastitis produced by coagulase-negative staphylococci. Marbofloxacin presented context-sensitive pharmacokinetics, influenced by the evolution of the disease, which decreased marbofloxacin disposition in serum and milk. Marbofloxacin showed a median (95% CI) fAUC/MIC values for MIC of 0.4 and 0.8 µg/mL of 26.66 (22.26-36.64) and 32.28 (26.57-48.35) related with -2 log10CFU/mL reduction; and 32.26 (24.81-81.50) and 41.39 (29.38-128.01) for -3 log10CFU/mL reduction in Mueller Hinton broth. For milk, -2 log10CFU/mL reduction was achieved with 41.48 (35.29-58.73) and 51.91 (39.09-131.63), and -3 log10CFU/mL reduction with 51.04 (41.6-82.1) and 65.65 (46.68-210.16). The proposed dose regimen was adequate for the treatment of goat mastitis produced by coagulase-negative staphylococci, resulting in microbiological and clinical cure of all animals. The animal model used in this study provided important pharmacokinetic information about the effect of the infection on the pharmacokinetics of marbofloxacin. Pharmacodynamic modeling showed that fAUC/MIC cutoff values were higher in goat milk compared with Mueller Hinton broth.

Staphylococcal Biofilm on the Surface of Catheters: Electron Microscopy Evaluation of the Inhibition of Biofilm Growth by RNAIII Inhibiting Peptide.

Staphylococcus aureus and coagulase-negative staphylococci (CoNS) have become the main causative agents of medical device-related infections due to their biofilm-forming capability, which protects them from the host's immune system and from the action of antimicrobials. This study evaluated the ability of RNA III inhibiting peptide (RIP) to inhibit biofilm formation in 10 strains isolated from clinical materials, including one S. aureus strain, two S. epidermidis, two S. haemolyticus, two S. lugdunensis, and one isolate each of the following species: S. warneri, S. hominis, and S. saprophyticus. The isolates were selected from a total of 200 strains evaluated regarding phenotypic biofilm production and the presence and expression of the ica operon. The isolates were cultured in trypticase soy broth with 2% glucose in 96-well polystyrene plates containing catheter segments in the presence and absence of RIP. The catheter segments were observed by scanning electron microscopy. The results showed inhibition of biofilm formation in the presence of RIP in all CoNS isolates; however, RIP did not interfere with biofilm formation by S. aureus. RIP is a promising tool that might be used in the future for the prevention of biofilm-related infections caused by CoNS.

Prevalence and effect of intramammary infection due to coagulase-negative staphylococcal (CNS) species in somatic cell counts in milk from Holstein dairy cows in Boyaca, Colombia / Prevalencia y efecto de la infección intramamaria debida a especies de estafilococos coagulasa negativo (ECN) en el conteo de células somáticas en leche de vacas Holstein en Boyacá, Colombia

ABSTRACT Mastitis is one of the most important illnesses in specialized dairy herds worldwide due to the effects on production and animal health. The types caused by CNS has a special importance in a production where the main pathogens are controlled. The objective of the present work is to determine the prevalence of CNS in a dairy herd in Boyaca and also quantify the effects of every species of CNS in SCC. 40 cows were selected and sampled during 6 months, CMT was performed, and results from 1 to trace were sampled. The routine bacteriological test was also performed for CNS identification, and the isolating of CNS was performed through rpoB gene identification and through the type of strain using the pulse gel electrophoresis procedure. Out of 960 samples, 619 were positive for CNS growth. The most prevalent species were Staphylococcus epidermidis, S. chromogenes, S. sciuri, S. simulaans, S. haemolyticus and S. capitis. The results that were found here are similar to the results observed in different parts of the world, which confirms that they are pathogens that must be constantly evaluated because they can go unnoticed in routine controls, especially in those farms where major pathogens are not a serious problem. The results determined in this study demonstrate that CNS generates a slight increase in somatic cells.

RESUMEN La mastitis es una de las enfermedades más importantes en los rebaños lecheros especializados alrededor de todo el mundo debido a los efectos sobre la producción y la salud animal. Los tipos ocasionados por estafilococos coagualasa negativo (ECN) tienen una importancia especial en una producción en la que los principales patógenos están controlados. El objetivo del presente trabajo es determinar la prevalência del ECN en un hato lechero en Boyacá y cuantificar los efectos de cada especie de ECN en el conteo de células somáticas (CCS). Se seleccionaron 40 vacas y se tomaron muestras durante 6 meses, se realizó california mastitis test (CMT) y se tomaron muestras de los resultados desde 1 hasta donde hubo trazas. También se realizó la prueba bacteriológica de rutina para la identificación del ECN y el aislamiento del ECN se realizó mediante la identificación del gen rpoB y del tipo de cepa, usando el procedimiento de electroforesis en gel de pulso. De 960 muestras, 619 fueron positivas para el crecimiento del ECN. Las especies más prevalentes fueron Staphylococcus epidermidis, S. chromogenes, S. sciuri, S. simulans, S. haemolyticus y S. capitis. Los resultados encontrados aquí son similares a resultados en diferentes partes del mundo, lo que confirma que son patógenos que deben ser evaluados constantemente porque pueden pasar desapercibidos en los controles de rutina, especialmente en aquellas fincas donde los patógenos mayores no son un problema grave. Los resultados determinados en este estudio demuestran que el SNC genera un ligero aumento de células somáticas.

Coagulase-Negative Staphylococci Clones Are Widely Distributed in the Hospital and Community.

Coagulase-negative staphylococci (CoNS) may be considered contaminants when isolated from clinical specimens but may also be a cause of true infection. This study aimed to compare the clonality and SCCmec type of a collection of CoNS isolated from blood cultures of inpatients, nasal swabs of healthy individuals, and patients with chronic wounds, all from the same community, using SCCmec typing, pulsed-field gel electrophoresis (PFGE), and MLST. Staphylococcus epidermidis, exhibited high clonal diversity, but hospital and community clusters were observed. Nosocomial S. epidermidis clones belonged to sequence types ST2, ST6, and ST23. Some Staphylococcus haemolyticus clones were found to circulate in the hospital and community, while Staphylococcus saprophyticus exhibited very high clonal diversity. Staphylococcus lugdunensis, Staphylococcus warneri, and Staphylococcus capitis revealed several isolates belonging to the same clone in the hospital and community. The detection of different SCCmec types within the same cluster indicated high diversity. S. epidermidis was associated with SCCmec I and III, S. haemolyticus with I and II, S. capitis with type V, Staphylococcus hominis with mec complex type A and ccr1, and S. warneri and S. saprophyticus with SCCmec I. The generation of elements and new combinations of cassette genes were highly associated with CoNS isolates, suggesting that SCCmec may not be a good marker of clonality in these bacteria.

Methicillin-Resistant Staphylococcus haemolyticus Displaying Reduced Susceptibility to Vancomycin and High Biofilm-Forming Ability.

BACKGROUND: Staphylococcus haemolyticus is one of the most frequently coagulasenegative staphylococci isolated from healthcare-associated infections, mainly those related to implanted medical devices. OBJECTIVES: This study aimed to determine the antimicrobial susceptibility profile and biofilm forming capacity of S. haemolyticus isolated from bloodstream infections. METHODS: A total of 40 S. haemolyticus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), antimicrobial susceptibility profile, SCCmec typing, ability to form biofilm on abiotic surface and occurrence of putative genes related to biofilm formation. RESULTS: One S. haemolyticus was susceptible to all antimicrobials. The other isolates (n=39) were resistant to cefoxitin; and among them 34 (87.2%) harbored the mecA gene into the SCCmec type I (5.9%), type III (29.4%), type IV (5.9%) and type V (20.6%); and 38.2% isolates were designated as NT. Apart from cefoxitin, 94.9% of the isolates were resistant to at least four antimicrobial classes, and 32.5% displayed minimal inhibitory concentration (MIC) values higher than 4.0 µg/mL for vancomycin. All isolates formed biofilm on polystyrene surface and were classified as strong biofilm-producers, except for one isolate. All isolates were negative for icaA gene, and the prevalence of the other genes was as follows: atl, 100%; fbp, 92.5%; aap, 90.0%; and bap, 20.0%. CONCLUSION: This study reports a high prevalence of methicillin-resistant S. haemolyticus displaying decreased susceptibility to vancomycin with the ability to form strong biofilms on abiotic surface. The results support the importance of controlling the adequate use of antimicrobials for the treatment of staphylococcal infections.

Coagulase-negative staphylococci clones are widely distributed in the hospital and community

Coagulase-negative staphylococci (CoNS) may be considered contaminants when isolated from clinical specimens but may also be a cause of true infection. This study aimed to compare the clonality and SCCmec type of a collection of CoNS isolated from blood cultures of inpatients, nasal swabs of healthy individuals, and patients with chronic wounds, all from the same community, using SCCmec typing, pulsed-field gel electrophoresis (PFGE), and MLST. Staphylococcus epidermidis, exhibited high clonal diversity, but hospital and community clusters were observed. Nosocomial S. epidermidis clones belonged to sequence types ST2, ST6, and ST23. Some Staphylococcus haemolyticus clones were found to circulate in the hospital and community, while Staphylococcus saprophyticus exhibited very high clonal diversity. Staphylococcus lugdunensis, Staphylococcus warneri, and Staphylococcus capitis revealed several isolates belonging to the same clone in the hospital and community. The detection of different SCCmec types within the same cluster indicated high diversity. S. epidermidis was associated with SCCmec I and III, S. haemolyticus with I and II, S. capitis with type V, Staphylococcus hominis with mec complex type A and ccr1, and S. warneri and S. saprophyticus with SCCmec I. The generation of elements and new combinations of cassette genes were highly associated with CoNS isolates, suggesting that SCCmec may not be a good marker of clonality in these bacteria.

Staphylococcal biofilm on the surface of catheters: electron microscopy evaluation of the inhibition of biofilm growth by RNAIII inhibiting peptide

Staphylococcus aureus and coagulase-negative staphylococci (CoNS) have become the main causative agents of medical device-related infections due to their biofilm-forming capability, which protects them from the host's immune system and from the action of antimicrobials. This study evaluated the ability of RNA III inhibiting peptide (RIP) to inhibit biofilm formation in 10 strains isolated from clinical materials, including one S. aureus strain, two S. epidermidis, two S. haemolyticus, two S. lugdunensis, and one isolate each of the following species: S. warneri, S. hominis, and S. saprophyticus. The isolates were selected from a total of 200 strains evaluated regarding phenotypic biofilm production and the presence and expression of the ica operon. The isolates were cultured in trypticase soy broth with 2% glucose in 96-well polystyrene plates containing catheter segments in the presence and absence of RIP. The catheter segments were observed by scanning electron microscopy. The results showed inhibition of biofilm formation in the presence of RIP in all CoNS isolates; however, RIP did not interfere with biofilm formation by S. aureus. RIP is a promising tool that might be used in the future for the prevention of biofilm-related infections caused by CoNS.

Staphylococcus cohnii endocarditis in native valve.

We present a first case of Staphylococcus cohnii endocarditis in an 80-year-old patient with a history of valve regurgitation. Endocarditis by this organism has not been reported previously. The patient declined treatment and died a few days later. When present, S. cohnii endocarditis has a poor prognosis as a result of associated comorbidities and the infection itself.

Coagulase-negative staphylococci in outpatient routines: the implications of switching from CLSI to BrCAST/EUCAST guidelines.

Coagulase-negative staphylococci (CoNS) are frequently isolated in clinical specimens and are important reservoirs of resistance genes. In 2019, the Brazilian government set the BrCAST/EUCAST (Brazilian Committee on Antimicrobial Susceptibility Testing) guidelines as the national standard, resulting in changes in the interpretation of CoNS susceptibility tests. From outpatients, disk-diffusion susceptibility of 65 CoNS cultures were evaluated and compared using classification criteria from both CLSI and BrCAST/EUCAST. The isolates were identified using matrix assisted laser desorption ionization-time of flight (MALDI-TOF), and the presence of the mecA gene was determined. The most prevalent species were Staphylococcus saprophyticus (32.3%), S. haemolyticus (18.5%), and S. epidermidis (9.2%). Almost perfect agreement was seen between the guidelines, except concerning oxacillin and gentamicin, and the prevalence of multidrug resistant isolates increased with the use of BrCAST/EUCAST. Of all, 15 (23.1%) isolates, mainly S. epidermidis and S. haemolyticus, were positive for the mecA gene, and only three were detected when using CLSI or BrCAST/EUCAST disk-diffusion screening. This, using either guideline, could reveal the difficulty of determining oxacillin resistance. Using warning zones or molecular methods might well be indicated for CoNS. In conclusion, adoption of the BrCAST/EUCAST guidelines will result in certain artificial changes in epidemiological susceptibility profiles, and clinicians and institutions should be aware of the possible implications.