Usefulness of SARS-CoV-2 antigen test sample as input for SARS-CoV-2 RT-PCR analysis.

SARS-CoV-2 rapid detection is of great interest to prevent viral dissemination. In that sense, antigen tests appeared as a very valuable tool to reach this goal. However, it is possible to obtain a negative result in those patients with low viral loads, and consequently, reverse transcription-polymerase chain reaction (RT-PCR) should be performed on samples from patients with a negative antigen test in which there is a strong suspicion of COVID infection. The common diagnostic algorithm involves taking a second sample for RT-PCR testing. This study evaluates the usefulness of the antigen test sample for carrying out RT-PCR analysis when necessary. Results obtained indicate that can be used a unique sample for both antigen test and RT-PCR. This data showed that it is possible to reduce excessive suspected individuals managing and so on increase staff security and patient comfort.

Microbiological diagnosis of spinal tuberculosis.

PURPOSE: The purpose of this study was to review the clinical features and diagnosis of spinal tuberculosis cases reported in the literature. METHODS: A medical literature search in the Medline Pubmed database was undertaken to review tuberculosis spinal infection and extra-pulmonary tuberculosis diagnosis improvement. We introduced the following search items and boolean operators: "spinal infection", "spinal tuberculosis infection", "microbiological diagnosis of spinal tuberculosis" and "spinal tuberculosis PCR." Single cases or series without microbiological diagnosis were rejected. Manuscript language was restricted to Spanish, French, and English versions. RESULTS AND CONCLUSIONS: Spinal tuberculosis is more common in developing countries and is probably underdiagnosed. Delayed diagnosis is characteristic; it worsens the prognosis and increases morbidity. The microbiological diagnosis is crucial for several reasons. Despite surgical treatment, medical treatment with anti-tuberculous drugs is always necessary. A total of 20-40% of the spinal tuberculosis patients show another locus of infection. Pulmonary location can become a public health problem. Previously treated patients for other tuberculosis locations, incomplete treatments, or poor adherence can change the M. tuberculosis sensitivity pattern. Drug resistance test becomes a major need in the microbiology laboratory. PCR diagnostic techniques advance the diagnosis and increase the sensitivity and specificity rate.

Resistance to linezolid is mediated by the cfr gene in the first report of an outbreak of linezolid-resistant Staphylococcus aureus.

BACKGROUND: From April through June 2008, we identified 12 patients in the intensive care unit and 3 patients on other wards infected with methicillin-resistant Staphylococcus aureus that was also resistant to linezolid. We investigated the mechanism of resistance--point mutations in domain V of 23S ribosomal RNA (rRNA) or presence of the cfr gene--involved in the outbreak. METHODS: Strains for the study were obtained in the intensive care unit and other wards. Minimal inhibitory concentrations were determined using automated methods, the E-test, or dilution in Mueller-Hinton agar in accordance with Clinical and Laboratory Standards Institute guidelines. Strains were genotyped using pulsed-field gel electrophoresis and were sequenced to determine the presence of point mutations in 23S rRNA. The presence of the cfr gene was determined by specific polymerase chain reaction. RESULTS: The minimal inhibitory concentrations of linezolid ranged from 16 mg/L to 32 mg/L, and all the strains were susceptible to tigecycline, vancomycin, and daptomycin. Typing of strains sequentially isolated by pulsed-field gel electrophoresis showed that each patient carried only 1 clonal type of linezolid-resistant, methicillin-resistant S. aureus as detected by sequential isolations. The presence of the cfr gene was confirmed in all the isolates. Furthermore, sequencing of domain V of 23S rRNA showed that the most common mechanism of linezolid resistance reported to date, mutation G2576T, was not detected in any of the strains analyzed. CONCLUSIONS: We report the presence of the cfr gene underlying the resistance mechanism involved in a clinical outbreak of linezolid-resistant S. aureus.

Synergy of Linezolid with Several Antimicrobial Agents against Linezolid-Methicillin-Resistant Staphylococcal Strains.

Linezolid is a synthetic oxazolydinone active against multi-resistant Gram-positive cocci that inhibits proteins synthesis by interacting with the 50S ribosomal subunit. Although linezolid-resistant strains are infrequent, several outbreaks have been recently described, associated with prolonged treatment with the antibiotic. As an alternative to monotherapy, the combination of different antibiotics is a commonly used option to prevent the selection of resistant strains. In this work, we evaluated combinations of linezolid with classic and new aminoglycosides (amikacin, gentamicin and plazomicin), carbapenems (doripenem, imipenem and meropenem) and fosfomycin on several linezolid- and methicillin-resistant strains of Staphylococcus aureus and S. epidermidis, isolated in a hospital intensive care unit in Madrid, Spain. Using checkerboard and time-kill assays, interesting synergistic effects were encountered for the combination of linezolid with imipenem in all the staphylococcal strains, and for linezolid-doripenem in S.epidermidis isolates. The combination of plazomicin seemed to also have a good synergistic or partially synergistic activity against most of the isolates. None of the combinations assayed showed an antagonistic effect.

Could ceftaroline be an alternative therapy for linezolid resistant Staphylococcus epidermidis infections in Intensive Care Medicine?

INTRODUCTION: Coagulase negative Staphylococcus continues generating interest in critically ill patients, due to their infections in extended admissions, in instrumented patients and due to their described multidrug resistance, which include glycopeptide heterorresistance and the increase in oxazolidinone resistance. Ceftaroline is a new cephalosporin with activity against resistant gram-positives, which, being betalactam, may provide adequate safety profile in the critical ill patient. The aim of this study was to determine the activity of ceftaroline and other antimicrobial agents against methicillin and linezolid-resistant Staphylococcus epidermidis. MATERIAL AND METHODS: We studied susceptibility of ceftaroline, tigecycline, daptomycin and vancomycin in a total of sixty-eight methicillin and linezolid-resistant S. epidermidis isolates with clinical significance from an Intensive Care Unit, using E-test. RESULTS: All strains were susceptible to the four antimicrobial agents, regardless of the level of resistance to linezolid. CONCLUSION: Ceftaroline could be an alternative in the treatment of methicillin and linezolid-resistant S. epidermidis infections in critically ill patients.

Characterization and monitoring of linezolid-resistant clinical isolates of Staphylococcus epidermidis in an intensive care unit 4 years after an outbreak of infection by cfr-mediated linezolid-resistant Staphylococcus aureus.

Resistance to linezolid is emerging among Staphylococcus epidermidis isolates. During the 4 years following an outbreak of cfr-mediated linezolid-resistant S. aureus in our intensive care unit in 2008, we analyzed the clinical context and characterized the resistance mechanisms of 100 linezolid-resistant strains of S. epidermidis. The prevalence of the cfr gene in our strains reached 50% alone or in combination with other mechanisms. The mutation G2576T in domain V was found in 22% of strains, and both the cfr gene and G2576T in 44%. We also found an association between the cfr gene and mutations in the ribosomal protein L3. All 3 mechanisms co-occurred in 1 strain. MICs in combinations rose to >256 µg/mL. 58% of colonized patients, and 90% of infected patients had previously received linezolid for at last 10 days. Vancomycin was the main antibiotic in these infections, most of which were bacteremia. We found a high prevalence of the cfr gene in our clinical S. epidermidis isolates after the 2008 outbreak, despite having implemented isolation and control measures. The potential transmissibility of this agent, even without prior exposure to linezolid, can have serious epidemiological repercussions.

Could ceftaroline be an alternative therapy for linezolid resistant Staphylococcus epidermidis infections in Intensive Care Medicine? / ¿Podría ceftarolina ser una alternativa terapéutica frente a las infecciones por Staphylococcus epidermidis en el paciente crítico?

Introduction. Staphylococcus coagulasa negativo sigue generando interés en los pacientes críticos, debido a sus infecciones en los ingresos prolongados, en pacientes instrumentados y, debido a su resistencia a múltiples fármacos descrito, que incluyen la heterorresistencia a glicopéptidos y el aumento de la resistencia oxazolidinonas. Ceftarolina es una nueva cefalosporina con actividad frente a grampositivos resistentes, que, por ser un betalactámico, podría proporcionar un perfil de seguridad adecuado en el paciente crítico. El objetivo de este estudio fue determinar la actividad de ceftarolina y otros agentes antimicrobianos frente a cepas de Staphylococcus epidermidis resistente a meticilina y linezolid. Material y métodos. Estudiamos la sensibilidad de ceftarolina, tigeciclina, daptomicina y vancomicina en un total de sesenta y ocho aislamientos con significación clínica de S. epidermidis resistente a meticilina y linezolid en una Unidad de Cuidados Intensivos, usando E-test. Resultados. Todas las cepas fueron sensibles a los cuatro agentes antimicrobianos, con independencia del nivel de resistencia a linezolid. Conclusión. Ceftarolina podría ser una alternativa en el tratamiento de infecciones por S. epidermidis resistente a meticilina y linezolid en el paciente crítico (AU)

Introduction. Coagulase negative Staphylococcus continues generating interest in critically ill patients, due to their infections in extended admissions, in instrumented patients and due to their described multidrug resistance, which include glycopeptide heterorresistance and the increase in oxazolidinone resistance. Ceftaroline is a new cephalosporin with activity against resistant gram-positives, which, being betalactam, may provide adequate safety profile in the critical ill patient. The aim of this study was to determine the activity of ceftaroline and other antimicrobial agents against methicillin and linezolid-resistant Staphylococcus epidermidis. Material and methods. We studied susceptibility of ceftaroline, tigecycline, daptomycin and vancomycin in a total of sixty-eight methicillin and linezolid-resistant S. epidermidis isolates with clinical significance from an Intensive Care Unit, using E-test. Results. All strains were susceptible to the four antimicrobial agents, regardless of the level of resistance to linezolid. Conclusion. Ceftaroline could be an alternative in the treatment of methicillin and linezolid-resistant S. epidermidis infections in critically ill patients (AU)