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Key Clinical Message: Methicillin‐resistant staph aureus (MRSA) infections are challenging to treat, and with the emergence of community‐associated MRSA (CA‐MRSA) strains, early consideration of this pathogen in populations without typical risk factors is critical. Here we present a case of CA‐MRSA pneumonia that resulted in Community‐acquired pneumonia (CAP) with septic shock, pyelonephritis, and muscle abscess. [ABSTRACT FROM AUTHOR]

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) is a well-recognized cause of bacterial pneumonia in general. The gut microbiota and their metabolic byproducts act as important modulators of the gut-lung axis. Our investigation indicates a significant reduction in the abundance of butyrate producer unclassified_f__Lachnospiraceae within the lung and gut microbiota of MRSA-infected mice, as well as a significant decrease in the levels of butyrate in gut and serum. Additionally, supplementary sodium butyrate (NaB) significantly reduces bacteria colonization in the lung, suppresses pro-inflammatory cytokines expression, and enhances lung tissue morphology in MRSA-treated mice. The results of high-throughput 16S rDNA sequencing demonstrate that NaB reshapes the gut and lung microbiota by drastically reducing the abundance of potential pathogenic bacteria in the gut and cell motility-related bacteria in the lung, which are induced by MRSA. Moreover, NaB treatment augments the gut and circulating butyrate levels. Mechanistically, NaB promotes signal transducer and activator of transcription 1 (STAT1) acetylation and inhibits dimer STAT1 phosphorylation by reducing the binding of histone deacetylase 3 to STAT1, thereby altering alveolar macrophage polarization toward the M2 phenotype. Collectively, our findings suggest that NaB exerts a preventative effect against MRSA-induced pneumonia by enhancing the gut-lung microbiota and promoting macrophage polarization toward an anti-inflammatory M2 phenotype. The prophylactic administration of NaB emerges as a promising strategy for combating MRSA pneumonia. IMPORTANCE Pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) continues to carry a high burden in terms of mortality. With the roles of gut microbiota in mediating lung diseases being gradually uncovered, the details of the molecular mechanism of the “gut-lung axis” mediated by beneficial microorganisms and small-molecule metabolites have gradually attracted the attention of researchers. However, further studies are still necessary to determine the efficacy of microbial-based interventions. Our findings indicate that sodium butyrate (NaB) alleviates MRSA-induced pulmonary inflammation by improving gut-lung microbiota and promoting M2 polarization of alveolar macrophages. Therefore, the preventive administration of NaB might be explored as an effective strategy to control MRSA pneumonia.

Pneumothorax is a potentially fatal complication in patients with acute respiratory distress syndrome (ARDS), presenting challenges in determining the optimal positive end-expiratory pressure (PEEP) level to prevent atelectasis without exacerbating the pneumothorax. This case report describes the successful application of transpulmonary pressure and electrical impedance tomography (EIT) at the bedside to guide PEEP selection in a patient with ARDS complicated by pneumothorax due to methicillin-resistant Staphylococcus aureus infection. By using minimal PEEP to maintain positive end-expiratory transpulmonary pressure and visualizing lung reopening with EIT, the optimal PEEP level was reaffirmed, even if traditionally considered high. The patient’s condition improved, and successful weaning from the ventilator was achieved, leading to a transfer out of the intensive care unit.Clinical trial registration: https://clinicaltrials.gov/show/NCT04081142, identifier NCT04081142.

In the early stages of treating patients with SARS-CoV-2, limited information was available to guide antimicrobial stewardship interventions. The COVID-19 Task Force and Antimicrobial Stewardship Committee, at a 988-bed academic medical center, implemented the use of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab polymerase chain reaction (PCR) testing to assist with the de-escalation of anti-MRSA therapy in patients with suspected superimposed bacterial pneumonia in COVID-19. A retrospective study was conducted to evaluate the impact of MRSA nasal swab PCR testing on the rate of anti-MRSA therapy between 13 April 2020 and 26 July 2020. A total of 122 patients were included in the analysis. Of the patients included in the final analysis, 58 (47.5%) had anti-MRSA therapy discontinued and 41 (33.6%) avoided anti-MRSA therapy completely due to a negative swab result. With the implementation of MRSA nasal swab PCR testing in COVID-19 patients, anti-MRSA therapy was reduced in 81% of patients in this study. In patients who continued with anti-MRSA therapy, nasal swabs were either positive for MRSA or an alternative indication for anti-MRSA therapy was noted. Only three patients in the cohort had MRSA identified in a sputum culture, all of whom had anti-MRSA therapy continued. MRSA nasal swab PCR testing may serve as an effective antimicrobial stewardship tool in COVID-19 pneumonia. [ABSTRACT FROM AUTHOR]

UnlabelledElectronic (e)-cigarette use is rapidly rising, with 20 % of Americans ages 25-44 now using these drug delivery devices. E-cigarette users expose their airways, cells of host defense, and colonizing bacteria to e-cigarette vapor (EV). Here, we report that exposure of human epithelial cells at the air-liquid interface to fresh EV (vaped from an e-cigarette device) resulted in dose-dependent cell death. After exposure to EV, cells of host defense-epithelial cells, alveolar macrophages, and neutrophils-had reduced antimicrobial activity against Staphylococcus aureus (SA). Mouse inhalation of EV for 1 h daily for 4 weeks led to alterations in inflammatory markers within the airways and elevation of an acute phase reactant in serum. Upon exposure to e-cigarette vapor extract (EVE), airway colonizer SA had increased biofilm formation, adherence and invasion of epithelial cells, resistance to human antimicrobial peptide LL-37, and up-regulation of virulence genes. EVE-exposed SA were more virulent in a mouse model of pneumonia. These data suggest that e-cigarettes may be toxic to airway cells, suppress host defenses, and promote inflammation over time, while also promoting virulence of colonizing bacteria.Key messageAcute exposure to e-cigarette vapor (EV) is cytotoxic to airway cells in vitro. Acute exposure to EV decreases macrophage and neutrophil antimicrobial function. Inhalation of EV alters immunomodulating cytokines in the airways of mice. Inhalation of EV leads to increased markers of inflammation in BAL and serum. Staphylococcus aureus become more virulent when exposed to EV.

In the early stages of treating patients with SARS-CoV-2, limited information was available to guide antimicrobial stewardship interventions. The COVID-19 Task Force and Antimicrobial Stewardship Committee, at a 988-bed academic medical center, implemented the use of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab polymerase chain reaction (PCR) testing to assist with the de-escalation of anti-MRSA therapy in patients with suspected superimposed bacterial pneumonia in COVID-19. A retrospective study was conducted to evaluate the impact of MRSA nasal swab PCR testing on the rate of anti-MRSA therapy between 13 April 2020 and 26 July 2020. A total of 122 patients were included in the analysis. Of the patients included in the final analysis, 58 (47.5%) had anti-MRSA therapy discontinued and 41 (33.6%) avoided anti-MRSA therapy completely due to a negative swab result. With the implementation of MRSA nasal swab PCR testing in COVID-19 patients, anti-MRSA therapy was reduced in 81% of patients in this study. In patients who continued with anti-MRSA therapy, nasal swabs were either positive for MRSA or an alternative indication for anti-MRSA therapy was noted. Only three patients in the cohort had MRSA identified in a sputum culture, all of whom had anti-MRSA therapy continued. MRSA nasal swab PCR testing may serve as an effective antimicrobial stewardship tool in COVID-19 pneumonia.

Acute methicillin-resistant Staphylococcus aureus (MRSA) pneumonia is a common and serious lung infection with high morbidity and mortality rates. Due to the increasing antibiotic resistance, toxicity, and pathogenicity of MRSA, there is an urgent need to explore effective antibacterial strategies. In this study, we developed a dry powder inhalable formulation which is composed of porous microspheres prepared from poly(lactic- co -glycolic acid) (PLGA), internally loaded with indocyanine green (ICG)-modified, heat-resistant phages that we screened for their high efficacy against MRSA. This formulation can deliver therapeutic doses of ICG-modified active phages to the deep lung tissue infection sites, avoiding rapid clearance by alveolar macrophages. Combined with the synergistic treatment of phage therapy and photothermal therapy, the formulation demonstrates potent bactericidal effects in acute MRSA pneumonia. With its long-term stability at room temperature and inhalable characteristics, this formulation has the potential to be a promising drug for the clinical treatment of MRSA pneumonia.

Purpose Colonization of methicillin-resistant Staphylococcus aureus (MRSA) can be detected via nasal screens. Evidence indicates that negative MRSA nasal screens may be used to de-escalate anti-MRSA antibiotics in pulmonary infections. In the ICU, universal decolonization with intranasal mupirocin is implemented to reduce MRSA infection risk. This study aimed to determine whether mupirocin administration affects the reliability of MRSA PCR nasal screens. Methods This retrospective study divided subjects based on timing of intranasal mupirocin administration—before and after MRSA screen. Subjects with confirmed pulmonary infection that received vancomycin, blood/respiratory cultures, and had MRSA PCR screen collected were included. Subjects with concurrent infection requiring vancomycin or MRSA infection in prior 30 days were excluded. Primary outcome of this non-inferiority study was the negative predictive value (NPV) of the screen. Secondary outcomes included the positive predictive value (PPV), sensitivity, and specificity of the screen and duration of vancomycin. Results Ultimately, 125 subjects were included in each group. The NPV in the group receiving mupirocin before screen was 95.2%, whereas the NPV in the group receiving mupirocin after screen was 99%. The difference between groups was -3.8% (90% CI -7.8%-0.2%; p=0.31), which failed to meet non-inferiority criteria. The secondary outcomes of PPV, sensitivity and specificity of the screen were similar in both groups. The duration of vancomycin was significantly longer in subjects receiving mupirocin before screen (3 days vs. 2 days; p<0.05). Conclusion Intranasal mupirocin prior to the screen may reduce NPV in pulmonary infections. Approach de-escalation of vancomycin based on screen results with caution. [ABSTRACT FROM AUTHOR]

Objective: To review the evidence for trimethoprim-sulfamethoxazole (TMP-SMX), clindamycin, doxycycline, and minocycline in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. Data Source: MEDLINE, PubMed, EMBASE, Google, Google Scholar, Cochrane Central Register of Controlled Trials from 1946 to May 20, 2019. The search was performed with the keywords methicillin-resistant Staphylococcus aureus, MRSA, Staphylococcus aureus, pneumonia, trimethoprim, sulfamethoxazole drug combination, trimethoprim, sulfamethoxazole, TMP-SMX, co-trimoxazole, clindamycin, doxycycline, and minocycline. Data Extraction: Studies reporting the use of the above antibiotics for MRSA pneumonia treatment with clinical outcomes were included. Search parameters were limited to English language and human studies only. Data Synthesis: The search yielded 16 relevant articles: 6 TMP-SMX, 8 clindamycin, zero doxycycline, and 2 minocycline. For TMP-SMX, prospective randomized trials showed variable results; however, these studies were not specifically designed to assess MRSA pneumonia treatment. Retrospective studies with clindamycin suggested that it could be used as monotherapy or in combination with other anti-MRSA antibiotics. There was no evidence for doxycycline use, but 2 small retrospective reviews appeared to support minocycline as a treatment option. Relevance to Patient Care and Clinical Practice: These antibiotics are often used in clinical practice as potential treatment options for MRSA pneumonia. This article reviews the evidence for the clinical efficacy and safety of these agents. Conclusions: There are limited data to support use of TMP-SMX, clindamycin, doxycycline, or minocycline in MRSA pneumonia treatment. Randomized controlled trials are required to determine the effectiveness of these antibiotics. Clinicians should base their decision to use these agents on a case-by-case basis depending on clinical status and susceptibility results. [ABSTRACT FROM AUTHOR]

Linezolid is an oxazolidinone antibiotic with activity against gram-positive organisms, particularly methicillin-resistant Staphylococcus aureus (MRSA). To the best of our knowledge, there are only two case reports on rhabdomyolysis in patients treated with linezolid. Here, we describe two cases of serious rhabdomyolysis: one in a patient with septic community-acquired (CA)-MRSA pneumonia and a second case in a patient with suspected catheter-related blood stream infection. [ABSTRACT FROM AUTHOR]

Acute respiratory distress syndrome (ARDS) is a life-threatening lung injury characterized by rapid onset of widespread inflammation in the lungs. Multiple risk factors, including pneumonia, non-pulmonary sepsis, aspiration of gastric contents or inhalation injury, have been reported, to cause ARDS. We present a case of a healthy young woman in her first trimester with vaping-induced lung injury who presented with spontaneous pneumothorax and acute respiratory distress syndrome with concomitant influenza A and rhinovirus infection followed by methicillin-resistant Staphylococcus aureus pneumonia., Competing Interests: Conflict of interest All the authors declare no conflict of interest., (© 2023 Greater Baltimore Medical Center.)

Background: Opioids are widely used in clinical practice. However, their long-term administration causes respiratory depression, addiction, tolerance, and severe immunosuppression. Traditional Chinese medicine (TCM) can alleviate opioid-induced adverse effects. Compound 511 is particularly developed for treating opioid addiction, based on Jiumi Liangfang, an ancient Chinese drug treatment and rehabilitation monograph completed in 1833 A.D. It is an herbal formula containing eight plants, each of them contributing to the overall pharmacological effect of the product: Panax ginseng C. A. Meyer (8.8%), Astragalus membranaceus (Fisch.) (18.2%), Datura metel Linn. (10.95%), Corydalis yanhusuo W. T. Wang (14.6%), Acanthopanar gracilistμlus W. W. Smith (10.95%), Ophiopogon japonicus (Linn. f.) Ker-Gawl. (10.95%), Gynostemma pentaphyllum (Thunb.) Makino (10.95%), Polygala arvensis Willd. (14.6%). This formula effectively ameliorates opioid-induced immunosuppression. However, the underlying mechanism remains unclear.Purpose: To reveal the effects of Compound 511 on the immune response of morphine-induced immunosuppressive mice and their potential underlying molecular mechanism. This study provides information for a better clinical approach and scientific use of opioids.Methods: Immunosuppression was induced in mice by repeated morphine administration. Th1/Th2/Th17/Treg cell levels were measured using flow cytometry. Splenic transcription factors of Th1/Th2/Th17/Treg and outputs of the regulatory PI3K/AKT/mTOR signaling pathway were determined. Subsequently, methicillin-resistant Staphylococcus aureus (MRSA) was administered intranasally to morphine-induced immunosuppressive mice pretreated with Compound 511. Their lung inflammatory status was assessed using micro-computer tomography (CT), hematoxylin and eosin (H&E) staining, and enzyme-linked immunosorbent assay (ELISA).Results: Compared to morphine, Compound 511 significantly decreased the immune organ indexes of mice, corrected the Th1/Th2 and Treg/Th17 imbalance in the immune organs and peripheral blood, reduced the mRNA levels of FOXP3 and GATA3, and increased those of STAT3 and T-bet in the spleen. It improved immune function and reduced MRSA-induced lung inflammation.Conclusion: Compound 511 ameliorates opioid-induced immunosuppression by regulating the balance of Th1/Th2 and Th17/Treg via PI3K/AKT/mTOR signaling pathway. Thus, it effectively reduces susceptibility of morphine-induced immunosuppressive mice to MRSA infection. [ABSTRACT FROM AUTHOR]

Background: Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outcomes. This study examined the association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia. Findings: This retrospective cohort study included 75 patients with MRSA pneumonia who were admitted to two large tertiary care medical centers during 2003-2010. Multivariable models were created using Cox proportional hazards regression and ordinal logistic regression to identify predictors of mortality or increased length of stay (LOS). None of the microbial characteristics (PFGE type, agr dysfunction, SCCmec type, and detection of PVL, ACME, and TSST-1) were significantly associated with 30-day mortality or post-infection hospital length of stay, after adjusting for gender, age, previous hospital admission within 12 months, previous MRSA infection or colonization, positive influenza test, Charlson Comorbidity Index score, and treatment (linezolid or vancomycin). Conclusion: Large prospective studies are needed to examine the impact of microbial characteristics on the risk of death and other adverse outcomes among patients with MRSA pneumonia. [ABSTRACT FROM AUTHOR]

Objective: To study the effects of linezolid and vancomycin in treatment of senile pneumonia of MRSA. Methods:Medical records of 60 senile MRSA pneumonia patients from October 2010 to 2013 in our hospital were collected and divided into linezolid group and vancomycin group, according to different treatments. The clinical efficacy, bacteriological effect, changes of inflammation factors, and safety evaluation of two groups were compared. Results: After a course of treatment, the effective rate of linezolid group was 83.33 %, higher than 86.67 % in the vancomycin group with no significant difference(P>0.05). The pathogen removal efficiency of linezolid group was 86.67 %, was higher than 84.33 % in the vancomycin group with no significant difference(P>0.05). Serum CRP,TNF-α levels showed no significant difference between two groups of patients before treatment(P>0.05). After a course of treatment,CRP, TNF-α levels of two groups were significantly lower than that before treatment(P<0.05), and CRP, TNF-α level of linezolid group were decreased significantly than that in vancomycin group(P<0.05). The adverse reaction incidence rate of linezolid group was 9.52 %,was lower than 16 % in vancomycin group, but no significant difference between the two groups(P>0.05). Conclusions: The cu- rative effect of linezolid and vancomycin in the treatment of elderly MRSA pneumonia is similar, but overall linezolid is better than vancomycin. [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 (COVID-19) pandemic has presented unprecedented challenges to the healthcare system globally, with opportunistic and secondary infections being one of the biggest challenges. Most secondary infections occur as nosocomial infections due to exposure to multidrug-resistant organisms in healthcare facilities. Secondary bacterial pneumonia complicates the care of hospitalized COVID-19 pneumonia patients. We present the case of a 77-year-old male who was diagnosed with COVID-19 pneumonia about four weeks before the current presentation to the hospital and was treated symptomatically in the community setting. During workup, he was diagnosed with multifocal pneumonia and right-sided empyema caused by methicillin-resistant Staphylococcus aureus (MRSA). He underwent chest tube thoracostomy followed by intrapleural fibrinolysis along with targeted antibiotic therapy. He needed video-assisted thoracoscopy with decortication due to inadequate improvement with intrapleural fibrinolysis. This case is a rare presentation of a community-acquired MRSA lung infection that occurred after recovery from COVID-19 pneumonia. This case emphasizes the importance of monitoring for secondary infections, as well as highlights the extent of secondary infections in COVID-19., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, McCraw et al.)

Abstract: Aim: To discuss the application of external beam radiotherapy (EBRT) and technetium-99m-labeled red blood cell scintigraphy (LRBCS) in life-threatening hemoptysis from a non-malignant condition. Materials and methods: This case report presents a patient with persistent hemoptysis secondary to chronic Methicillin-resistant Staphylococcus aureus (MRSA) infection in whom conventional management failed to localize the site of pulmonary bleeding or to provide effective therapy. Results: EBRT was successfully given for life-threatening hemoptysis with improvement in quality of life for nearly 1 year. LRBCS was used to localize the source of further bleeding and facilitate targeted therapy. Conclusion: EBRT can be an effective and well-tolerated modality in treating life-threatening hemoptysis refractory to conventional methods. LRBCS is a non-invasive diagnostic tool that can be used to detect the source of pulmonary bleeding. [Copyright &y& Elsevier]

Objective: To review the evidence for trimethoprim-sulfamethoxazole (TMP-SMX), clindamycin, doxycycline, and minocycline in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. Data Source: MEDLINE, PubMed, EMBASE, Google, Google Scholar, Cochrane Central Register of Controlled Trials from 1946 to May 20, 2019. The search was performed with the keywords methicillin-resistant Staphylococcus aureus , MRSA, Staphylococcus aureus , pneumonia, trimethoprim, sulfamethoxazole drug combination, trimethoprim, sulfamethoxazole, TMP-SMX, co-trimoxazole, clindamycin, doxycycline, and minocycline. Data Extraction: Studies reporting the use of the above antibiotics for MRSA pneumonia treatment with clinical outcomes were included. Search parameters were limited to English language and human studies only. Data Synthesis: The search yielded 16 relevant articles: 6 TMP-SMX, 8 clindamycin, zero doxycycline, and 2 minocycline. For TMP-SMX, prospective randomized trials showed variable results; however, these studies were not specifically designed to assess MRSA pneumonia treatment. Retrospective studies with clindamycin suggested that it could be used as monotherapy or in combination with other anti-MRSA antibiotics. There was no evidence for doxycycline use, but 2 small retrospective reviews appeared to support minocycline as a treatment option. Relevance to Patient Care and Clinical Practice: These antibiotics are often used in clinical practice as potential treatment options for MRSA pneumonia. This article reviews the evidence for the clinical efficacy and safety of these agents. Conclusions: There are limited data to support use of TMP-SMX, clindamycin, doxycycline, or minocycline in MRSA pneumonia treatment. Randomized controlled trials are required to determine the effectiveness of these antibiotics. Clinicians should base their decision to use these agents on a case-by-case basis depending on clinical status and susceptibility results.