Fusogenic porous silicon nanoparticles as a broad-spectrum immunotherapy against bacterial infections

Bacterial infections are re-emerging as substantial threats to global health due to the limited selection of antibiotics that are capable of overcoming antibiotic-resistant strains. By deterring such mutations whilst minimizing the need to develop new pathogen-specific antibiotics, immunotherapy offers a broad-spectrum therapeutic solution against bacterial infections. In particular, pathology resulting from excessive immune response (i.e. fibrosis, necrosis, exudation, breath impediment) contributes significantly to negative disease outcome. Herein, we present a nanoparticle that is targeted to activated macrophages and loaded with siRNA against the Irf5 gene. This formulation is able to induce >80% gene silencing in activated macrophages in vivo, and it inhibits the excessive inflammatory response, generating a significantly improved therapeutic outcome in mouse models of bacterial infection. The versatility of the approach is demonstrated using mice with antibiotic-resistant Gram-positive (methicillin-resistant Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) muscle and lung infections, respectively. Effective depletion of the Irf5 gene in macrophages is found to significantly improve the therapeutic outcome of infected mice, regardless of the bacteria strain and type.

Exploring Virulence Factors and Alternative Therapies against Staphylococcus aureus Pneumonia

Pneumonia is an acute pulmonary infection associated with high mortality and an immense financial burden on healthcare systems. Staphylococcus aureus is an opportunistic pathogen capable of inducing S. aureus pneumonia (SAP), with some lineages also showing multidrug resistance. Given the high level of antibiotic resistance, much research has been focused on targeting S. aureus virulence factors, including toxins and biofilm-associated proteins, in an attempt to develop effective SAP therapeutics. Despite several promising leads, many hurdles still remain for S. aureus vaccine research. Here, we review the state-of-the-art SAP therapeutics, highlight their pitfalls, and discuss alternative approaches of potential significance and future perspectives.

Association of Staphylococcus aureus Colonization and Pneumonia in the Intensive Care Unit

IMPORTANCE

Carriage of Staphylococcus aureus is associated with S aureus infection. However, associations between S aureus carriage and the development of S aureus intensive care unit (ICU) pneumonia (SAIP) have not been quantified accurately, and interpretation of available data is hampered because of variations in definitions.

OBJECTIVE

To quantify associations of patient-related and contextual factors, including S aureus colonization status, with the occurrence of SAIP.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted in ICUs of 30 hospitals in 11 European countries, geographically spread across 4 regions. Among patients with an anticipated length of stay 48 hours or longer who were undergoing mechanical ventilation at ICU admission, S aureus colonization was ascertained in the nose and lower respiratory tract. From this group, S aureus-colonized and noncolonized patients were enrolled into the study cohort in a 1:1 ratio. Data analysis was performed from May to November 2019.

MAIN OUTCOMES AND MEASURES

SAIP was defined as any pneumonia during the ICU stay developing 48 hours or more after ICU admission with S aureus isolated from lower respiratory tract specimens or blood samples. The incidence of SAIP was derived in the study cohort and estimated on the weighted incidence calculation for the originating overarching population, while taking competing events into account. Weighted risk factor analysis was performed using Cox multivariable regression.

RESULTS

The study cohort consisted of 1933 patients (mean [SD] age, 62.0 [16.0] years); 1252 patients (64.8%) were men, and 950 patients (49.1%) were S aureus carriers at ICU admission. In all, 304 patients (15.7%) developed ICU-acquired pneumonia, of whom 131 patients (6.8%) had SAIP. Weighted SAIP incidences were 11.7 events per 1000 patient-days in the ICU for S aureus-colonized patients and 2.9 events per 1000 patient-days in the ICU for noncolonized patients (overall incidence, 4.9 events per 1000 patient-days in the ICU). The only factor independently associated with SAIP was S aureus colonization status at ICU admission (cause-specific hazard ratio, 3.6; 95% CI, 2.2-6.0; P < .001). There were marked regional differences in SAIP incidence and cause-specific hazard ratios for colonization status.

CONCLUSIONS AND RELEVANCE

SAIP incidence was 4.9 events per 1000 ICU patient-days for patients undergoing mechanical ventilation at ICU admission (or shortly thereafter). The daily risk of SAIP was 3.6 times higher in patients colonized with S aureus at ICU admission compared with noncolonized patients.

Panton-Valentine Leukocidin-Secreting Staphylococcus aureus Pneumonia Complicating COVID-19

Necrotizing pneumonia induced by Panton-Valentine leukocidin–secreting Staphylococcus aureus is a rare but life-threatening infection that has been described in patients after they had influenza. We report a fatal case of this superinfection in a young adult who had coronavirus disease.

Childhood pneumonia in low-and-middle-income countries: An update

OBJECTIVES

To review epidemiology, aetiology and management of childhood pneumonia in low-and-middle-income countries.

DESIGN

Review of published English literature between 2013 and 2019.

RESULTS

Pneumonia remains a major cause of morbidity and mortality. Risk factors include young age, malnutrition, immunosuppression, tobacco smoke or air pollution exposure. Better methods for specimen collection and molecular diagnostics have improved microbiological diagnosis, indicating that pneumonia results from several organisms interacting. Induced sputum increases microbiologic yield for Bordetella pertussis or Mycobacterium tuberculosis, which has been associated with pneumonia in high TB prevalence areas. The proportion of cases due to Streptococcus pneumoniae and Haemophilus influenzae b has declined with new conjugate vaccines; Staphylococcus aureus and H. influenzae non-type b are the commonest bacterial pathogens; viruses are the most common pathogens. Effective interventions comprise antibiotics, oxygen and non-invasive ventilation. New vaccines have reduced severity and incidence of disease, but disparities exist in uptake.

CONCLUSION

Morbidity and mortality from childhood pneumonia has decreased but a considerable preventable burden remains. Widespread implementation of available, effective interventions and development of novel strategies are needed.

Mesenchymal stem cells significantly improved treatment effects of Linezolid on severe pneumonia in a rabbit model

The present study aimed to investigate whether co-administration of mesenchymal stromal cells (MSC) and linezolid (LZD) into a rabbit model of methicillin-resistant Staphylococcus aureus (MRSA)-infected pneumonia would bring a synergistic therapeutic effect. Human umbilical cord-derived MSCs (hUMSCs) were isolated and characterized. A rabbit model of pneumonia was constructed by delivering 1 × 1010 CFU MRSA via a bronchoscope into the basal segment of lower lobe of right lung. Through analyzing vital sign, pulmonary auscultation, SpO2, chest imaging, bronchoscopic manifestations, pathology, neutrophil percentage, and inflammatory factors, we verified that a rabbit model of MRSA-induced pneumonia was successfully constructed. Individual treatment with LZD (50 mg/kg for two times/day) resulted in improvement of body weight, chest imaging, bronchoscopic manifestations, histological parameters, and IL-10 concentration in plasma (P<0.01), decreasing pulmonary auscultation, and reduction of IL-8, IL-6, CRP, and TNF-α concentrations in plasma (P<0.01) compared with the pneumonia model group at 48 and 168 h. Compared with LZD group, co-administration of hUMSCs (1 × 106/kg for two times at 6 and 72 h after MRSA instillation) and LZD further increased the body weight (P<0.05). The changes we observed from chest imaging, bronchoscopic manifestations and pathology revealed that co-administration of hUMSCs and LZD reduced lung inflammation more significantly than that of LZD group. The plasma levels of IL-8, IL-6, CRP, and TNF-α in combined group decreased dramatically compared with the LZD group (P<0.05). In conclusion, hUMSCs administration significantly improved therapeutic effects of LZD on pneumonia resulted from MRSA infection in a rabbit model.

Oral administration of Lactobacillus acidophilus alleviates exacerbations in Pseudomonas aeruginosa and Staphylococcus aureus pulmonary infections

Staphylococcus aureus and Pseudomonas aeruginosa are largely the cause of morbidity and mortality in both hospital and community settings. These pathogens remain the important cause of pulmonary infections in patients with cystic fibrosis with a worldwide prevalence. Although, antibiotics are efficient measures of treating bacterial lung infections, the occurrence of antibiotic resistant bacteria has been encouraging the researchers to explore novel therapeutic approaches. It has been discovered that certain lactic acid bacteria possess protective effects against bacterial and viral respiratory infections. The aim of present study was to investigate the capability of orally administered L. acidophilus to ameliorate S. aureus and P. aeruginosa pulmonary infections. Animals were exposed to aerosol of pathogenic suspension. After 24 hours of infection, L. acidophilus treatment was administered orally for 7 consecutive days. Evaluation of tissue bacteriology, histopathology and serum cytokinomics were performed. In parallel, human alveolar A549 cells were utilized to determine possible role of probiotic on pulmonary infections. Oral administration of L. acidophilus significantly (P<0.05) alleviate lung bacterial load and severity of infection as depicted by our histopathological studies. Results obtained from cytokinomics revealed that pro-inflammatory cytokines induced due to lung infection were suppressed in oral probiotic treatment groups. In addition, treatment with L. acidophilus induced murine lung anti inflammatory, IL-10 cytokine level. Current work suggests that orally administered L. acidophilus in mice is able to attenuate S. aureus and P. aeruginosa induced lung cytotoxicity by modulation of host immune response.

Ventilator-Associated Pneumonia Patients who Do Not Reduce Bacteria from the Lungs have a Worse Prognosis

The authors determined the significance of serial semi-quantitative bronchoalveolar lavage (BAL) culture results in patients undergoing therapy for ventilator-associated pneumonia. A total of 32 patients underwent at least 2 nonbronchoscopic BAL studies. Fourteen patients had methicillin-resistant Staphylococcus aureus(MRSA). Of these, 11 had more than 100 colony-forming units (cfu) of MRSA/mL of BAL from the follow-up BAL. Eighteen patients had an organism other than MRSA, and 7 of these patients had > 100 cfu of bacteria/mL of BAL from the follow-up BAL. Of the 18 patients with > 100 cfu of bacteria/mL of BAL at follow-up, 14 (79%) died, whereas only 5 of 14 (36%) patients who cleared their bacteria at follow-up died within 28 days. The inability to reduce the bacterial burden from the lower respiratory tract within the first few days of therapy for ventilator-associated pneumonia was associated with increased mortality.

In a canine pneumonia model of exchange transfusion, altering the age but not the volume of older red blood cells markedly alters outcome

BACKGROUND

Massive exchange transfusion of 42-day-old red blood cells (RBCs) in a canine model of Staphylococcus aureus pneumonia resulted in in vivo hemolysis with increases in cell-free hemoglobin (CFH), transferrin-bound iron (TBI), non-transferrin-bound iron (NTBI), and mortality. We have previously shown that washing 42-day-old RBCs before transfusion significantly decreased NTBI levels and mortality, but washing 7-day-old RBCs increased mortality and CFH levels. We now report the results of altering volume, washing, and age of RBCs.

STUDY DESIGN AND METHODS

Two-year-old purpose-bred infected beagles were transfused with increasing volumes (5-10, 20-40, or 60-80 mL/kg) of either 42- or 7-day-old RBCs (n = 36) or 80 mL/kg of either unwashed or washed RBCs with increasing storage age (14, 21, 28, or 35 days; n = 40).

RESULTS

All volumes transfused (5-80 mL/kg) of 42-day-old RBCs resulted in alike (i.e., not significantly different) increases in TBI during transfusion as well as in CFH, lung injury, and mortality rates after transfusion. Transfusion of 80 mL/kg RBCs stored for 14, 21, 28, and 35 days resulted in increased CFH and NTBI in between levels found at 7 and 42 days of storage. However, washing RBCs of intermediate ages (14-35 days) does not alter NTBI and CFH levels or mortality rates.

CONCLUSIONS

Preclinical data suggest that any volume of 42-day-old blood potentially increases risks during established infection. In contrast, even massive volumes of 7-day-old blood result in minimal CFH and NTBI levels and risks. In contrast to the extremes of storage, washing blood stored for intermediate ages does not alter risks of transfusion or NTBI and CFH clearance.

Successful treatment of Panton-Valentine leukocidin-expressing Staphylococcus aureus-associated pneumonia co-infected with influenza using extracorporeal membrane oxygenation

BACKGROUND

Panton-Valentine leukocidin (PVL) is a cytotoxin that causes leukocyte destruction and lung necrosis. Managing respiratory failure and acute respiratory distress syndrome secondary to PVL-expressing Staphylococcus aureus pneumonia and its associated lung necrosis with mechanical ventilation is challenging. We report a patient with life-threatening PVL-expressing S. aureus-associated pneumonia who was rescued using extracorporeal membrane oxygenation (ECMO).

CASE REPORT

We examined the case of a woman who presented to our Emergency Department with septic shock due to PVL-expressing S. aureus-associated pneumonia. A 27-year-old Filipino woman was transferred to our hospital due to severe dyspnea, hemosputum, and high-grade fever. She had a medical history of osteosarcoma of the leg and hyperthyroidism. On arrival, her vital signs indicated septic shock, with a white blood cell count of 3.5×10(3)/μl. Because a Gram stain of her sputum indicated SA, therapy with antibiotics, including meropenem and vancomycin, was started. Hypoxemia necessitated intubation and ventilation. Because the patient's PaO2/FiO2 remained less than 60 mmHg and her blood pressure was unstable despite aggressive conventional management, venoarterial ECMO was administered approximately 11 h after her arrival. The ECMO circuit was changed to veno-venous ECMO on day 7 and the patient was successfully weaned off ECMO after 12 days of treatment. She was discharged from the hospital 104 days after admission.

CONCLUSION

This case demonstrates that early induction of ECMO support can be a reasonable therapeutic option for PVL-S. aureus-associated pneumonia. This patient's successful outcome might be attributable to early establishment of ECMO to prevent ventilation-induced lung injury.

A retrospective case series of 44 patients with community-acquired Staphylococcus aureus pneumonia

AIM

Staphylococcus aureus (S. aureus) community-acquired pneumonia (CAP) is a potentially devastating and life-threatening infection. Early detection and appropriate treatment is important to prevent morbidity and death. The aim of this case series was to investigate the patient demographics, clinical features, antibiotic treatment and complications of cases of community-acquired S. aureus pneumonia occurring in the Wellington region.

METHOD

The case records of patients with radiographically confirmed community-acquired pneumonia and laboratory evidence to support S. aureus as the causative organism admitted to Wellington Regional Hospital over a 5-year period (2007-2012) were retrospectively reviewed.

RESULTS

A total of 48 presentations in 44 patients met the inclusion criteria. The majority of patients (63.6%) had underlying comorbidities. Although the mean CURB65 score was only one and fever was uncommon, 30% of patients were admitted to ICU and 16% died in hospital. Significant infective complications occurred in 48% with new lung cavitation in 20%.

CONCLUSION

This series of patients with staphylococcal pneumonia confirms the significant morbidity and mortality of the infection. A low CURB65 score and lack of objective fever should not detract from the possibility of S. aureus. The presence of bacteraemia in patients with S. aureus pneumonia needs to be regarded as a potentially deleterious finding that may necessitate a change in treatment.

Emergency management of community-acquired bacterial pneumonia: what is new since the 2007 Infectious Diseases Society of America/American Thoracic Society guidelines

Community-acquired pneumonia (CAP) is a major health problem in the United States and is associated with substantial morbidity, mortality, and health care costs. Patients with CAP commonly present to emergency departments where physicians must make critical decisions regarding diagnosis and management of pneumonia in a timely fashion, with emphasis on efficient and cost-effective diagnostic choices, consideration of emerging antimicrobial resistance, timely initiation of antibiotics, and appropriate site-of-care decisions. In light of the burden that pneumonia places on health care systems and the emergency department in particular, this article reviews significant developments in the management of CAP in the United States 5 years since the publication of the 2007 Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of CAP in adults, focusing on recent studies and recommendations for managing CAP, the primary bacterial pathogens responsible for CAP, and trends in resistance, new diagnostic technologies, and newer antimicrobials approved for the treatment of CAP. These new data and additional guidelines pertaining to the treatment of CAP further our knowledge and understanding of this challenging infection. Furthermore, appreciation of the availability of new diagnostic testing and therapeutic options will help meet the demand for improved management of CAP.

Necrotizing pneumonia caused by Panton-Valentine leukocidin-producing methicillin-susceptible Staphylococcus aureus (MSSA)

Staphylococcus aureus harboured by Panton-Valentine leukocidin (PVL) is emerging as a serious problem worldwide. There has been an increase in the incidence of necrotizing lung infections in otherwise healthy young people with very high mortality rate associated with these strains. This report documents a confirmed case of necrotizing pneumonia due to methicillin-susceptible S. aureus (MSSA) harbouring Panton-Valentine leukocidin genes. An apparently healthy 49-year old man was admitted to our hospital for dyspnea and he quickly developed acute respiratory distress syndrome. MSSA harbouring Panton-Valentine leukocidin genes were cultured from the abscess fluid and from multiple blood specimens. Aggressive antibiotic therapy was started and intensive supportive care led finally to a complete recovery. Rapid identification of Panton-Valentine leukocidin in MSSA samples should be supposed when a young, immunocompetent patient, develops a necrotizing pneumonia. Bactericidal antistaphylococcal antibiotics are recommended for the treatment as soon as possible to avoid the potentially devastating consequences of this kind of S. aureus.

Community acquired methicillin resistant Staphylococcus aureus pneumonia: an update for the emergency and intensive care physician

Pneumonia caused by community-acquired (CA) methicillin-resistant Staphylococcus aureus (MRSA) among individuals without healthcare-associated (HA) risk factors was first recognized a decade ago. CA-MRSA has now been established as a pathogen responsible for rapidly progressive, frequently fatal disease manifesting as necrotizing pneumonia, severe sepsis and necrotizing fasciitis. The frequency of occurrence, risk factors, and optimal treatment of CA-MRSA pneumonia remain unclear and vary significantly across countries. CA-MRSA is resistant to β-lactam antimicrobials due to the acquisition of novel methicillin resistance genetic cassettes. Additionally many CA-MRSA strains produce Panton-Valentine leukocidin (PVL), due to which they probably exceed the virulence of hospital-acquired MRSA isolates (HA-MRSA). CA-MRSA pneumonia requires early suspicion -especially in young otherwise healthy individuals with rapidly evolving clinical picture presenting with cavitary consolidation, bilateral infiltrates, pleural effusion and hemoptysis. Prompt hospitalization and aggressive treatment with intravenous antibiotics is warranted to improve outcomes. Therapeutic approach for severe CA-MRSA infections and particularly pneumonia is generally the same as that for invasive HA-MRSA infections. New anti-MRSA agents and possible combinations are of great importance to be evaluated in the future.

Clinical and economic outcomes in patients with community-acquired Staphylococcus aureus pneumonia

BACKGROUND

While the clinical and economic consequences of S. aureus pneumonia in healthcare settings have been well documented, much less is known about community-acquired S. aureus pneumonia (CAP).

METHODS

We retrospectively identified all patients admitted to a large US urban teaching hospital between January 2005 and May 2008 with pneumonia and positive blood or respiratory cultures for S. aureus within 48 hours of admission. Patients with suspected healthcare-associated pneumonia (HCAP) were excluded from the study sample, using established criteria (eg, recent hospitalization, admission from nursing home, hemodialysis). Patients were designated as having methicillin-resistant (MRSA) or methicillin-susceptible (MSSA) CAP based on initial S. aureus isolates. Initial therapy was designated "appropriate" vs. "inappropriate" based on expected susceptibility of the organism to the regimen received.

RESULTS

We identified a total of 128 CAP patients with S. aureus isolates; mean (standard deviation [SD]) age was 60 (17) years. A total of 55 patients (43%) had initial cultures positive for MRSA. Patients with MRSA CAP were more likely to receive inappropriate initial therapy (24 [44%] vs. 13 [18%] for MSSA; P = 0.002). Approximately 25% of all patients underwent surgery for pneumonia, 69% received mechanical ventilation, 79% were admitted to intensive care unit (ICU), and 24% died in hospital. Mean (SD) length of stay was 17.0 (15.7) days, and total hospital charges averaged $127,922 ($154,605) per patient; there were no significant differences between patients with MRSA vs. MSSA CAP.

CONCLUSION

Outcomes are poor, hospital stays are long, and costs of care are high in patients with S. aureus CAP, and do not differ between those with MRSA vs. MSSA.

Three cases of correctional litigation: learning from the root causes

In correctional settings, deviations from the standard of care are not self-correcting as they would be for free persons who may request different opinions or change providers. Inmates are perceived as generally litigious and may file suits with frequency. The author analyzed three typical cases of correctional litigation. The allegations were failure to work up hemoptysis in a patient with asthma, leading to delays in the diagnosis of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia and death; failure to continue antiretroviral therapy (ART) plus failure to implement emergency treatment with antivirals specific for opportunistic infections of the eye, resulting in blindness; and failure to timely diagnose rhabdomyolysis with ensuing need for renal dialysis and accidental perforation of the vena cava and death. Analysis of the root causes led to the development of risk management techniques aimed at preventing medical mishaps and avoiding litigation.

A case of rapidly progressive necrotizing pneumonia caused by community-acquired methicillin-resistant Staphylococcus aureus

We present the case of a patient with a necrotizing multilobar pneumonia caused by community-acquired methicillin-resistant Staphylococcus aureus (MRSA). The patient presented with shortness of breath and a productive cough of 3 days duration. On arrival to the emergency department she was intubated for increased work of breathing and given vasopressors for hypotension refractory to fluid resuscitation. Blood cultures taken at admission, sputum cultures from the patient's endotracheal tube, and bronchoalveolar lavage cultures all grew S. aureus resistant to penicillinase-resistant penicillins. Over the following days the patient's respiratory function deteriorated as she grew progressively hypoxemic and hypercarbic despite aggressive mechanical ventilation and intravenous antibiotics. On day 4 of her hospitalization a computed tomogram revealed extensive pulmonary necrosis consistent with necrotizing pneumonia. The patient's family elected to withdraw support, and the patient rapidly died following cessation of mechanical ventilation.

[Two cases of severe necrotizing pneumonia caused by community-acquired methicillin-resistant Staphylococcus aureus]

We present 2 cases with severe necrotizing pneumonia due to community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection. The patients were a 89-year-old man and a male student of 15 years of age. Chest X-rays and CT scans demonstrated multiple consolidations with cavitary lesions showing necrotizing pneumonia. MRSA strains were isolated from the sputum cultures on admission in these patients who did not have any established risk factors for MRSA infections such as history of hospitalization, surgery, hemodialysis, the presence of a permanent indwelling catheter or percutaneous medical device, and residence in a long-term care facility. These patients thus satisfied the international criteria for CA-MRSA presented by the Centers for Disease Control and Prevention (CDC). Unfortunately, the first case died of CA-MRSA pneumonia in spite of intensive treatments including anti-MRSA antibiotics. Unlike the severe CA-MRSA cases in western countries, Panton-Valentine leukocidin (PVL) genes were not detected in the present cases, suggesting that factors other than PVL had a significant effect on the severity of necrotizing pneumonia. To the best of our knowledge, this is the first report of severe necrotizing pneumonia caused by CA-MRSA in Japan.

Diagnosis and treatment of Panton–Valentine leukocidin (PVL)-associated staphylococcal pneumonia

Panton-Valentine leukocidin (PVL)-producing Staphylococcus aureus is emerging as a serious problem worldwide. Whilst usually causing skin and soft-tissue infections, particularly recurrent abscesses, there has in the last 10 years been an increase in the incidence of an associated devastating pneumonia affecting previously healthy young people and associated with a very high mortality. There are no evidence-based guidelines to consult for the management of PVL-associated staphylococcal pneumonia. The literature contains less than 100 cases, with widely differing antimicrobial therapies and the occasional use of other adjunctive therapies such as intravenous immunoglobulin, activated protein C and extracorporeal membrane oxygenation. This literature review focuses on the salient features of diagnosis and management, with particular attention to the choice of antimicrobials.

A canine model of septic shock: balancing animal welfare and scientific relevance

A shock canine pneumonia model that permitted relief of discomfort with the use of objective criteria was developed and validated. After intrabronchial Staphylococcus aureus challenge, mechanical ventilation, antibiotics, fluids, vasopressors, sedatives, and analgesics were titrated based on algorithms for 96 h. Increasing S. aureus (1 to 8 x 10(9) colony-forming units/kg) produced decreasing survival rates (P = 0.04). From 4 to 96 h, changes in arterial-alveolar oxygen gradients, mean pulmonary artery pressure, IL-1, serum sodium levels, mechanical ventilation, and vasopressor support were ordered based on survival time [acute nonsurvivors (< or =24 h until death, n = 8) > or = subacute nonsurvivors (>24 to 96 h until death, n = 8) > or = survivors (> or =96 h until death, n = 22) (all P < 0.05)]. In the first 12 h, increases in lactate and renal abnormalities were greatest in acute nonsurvivors (all P < 0.05). Compared with survivors, subacute nonsurvivors had greater rises in cytokines and liver enzymes and greater falls in platelets, white cell counts, pH, and urine output from 24 to 96 h (all P < 0.05). Importantly, these changes were not attributable to dosages of sedation, which decreased in nonsurvivors [survivors vs. nonsurvivors: 5.0 +/- 1.0 vs. 3.8 +/- 0.7 ml x h(-1) x (fentanyl/midazolam/ medetomidine)(-1); P = 0.02]. In this model, the pain control regimen did not mask changes in metabolic function and lung injury or the need for more hemodynamic and pulmonary support related to increasing severity of sepsis. The integration into this model of both specific and supportive titrated therapies routinely used in septic patients may provide a more realistic setting to evaluate therapies for sepsis.

[Staphylococcus pneumonia--complications]

The paper presents the case of a 4-year-old child who was admitted with the diagnosis Dg: Pleuropneumonia lat. sin, while in the further course as a suspicion due to progressive flow as staphylococcus pneumonia. The illness is complex in terms of treatment. The diagnosis was set based on the history of illness, its clinical course, laboratory findings, radiology tests. The boy was hospitalized in January in current year with symptoms (coughing, vomiting and fever) that have been lingering for the past two days. The boy has been treated with a ternary antibiotic therapy (cephalosporin of third generation parenterally with aminoglycosides, plus anti-staphylococcus therapy). In laboratory findings Sedimentation rate increased 88/134 WBC 75 thousands. Radiologically extended pleuropneumonia on the left side. In sputum staphylococcus aureus was isolated. In the further course of hospitalization, due to the development of progressive form of staphylococcus pneumoniae with a fever of up to 39 degrees, pale aspect and dyspnoic patient with anemia and with complications in the form of cysts, ruptures and pneumothorax, with a thoracic drainage performed. In the further course, the cysts were gradually absorbed, while the thoracic drain was grafted. Clinically, the child was looking better. We continued the anti-staphylococcus therapy (stanicide), to which the child reacted well clinically and radiologically. Auscultatory breathing on the left side was audible. The last follow-up and the last rtg pulmo et cor 6 months after the outbreak of illness with a complete regression of the foregoing changes.

Video-assisted thoracoscopic surgery in a 1-month-old infant with pleural empyema

Pleural empyema is a frequent complication of bacterial pneumonia in childhood but is rare in neonates. Various modalities of treatment from intravenous antibiotics, chest tube drainage, intrapleural fibrinolytic agent installation, video-assisted thoracostomy to surgical decortication have been suggested to treat different stages of empyema in children, but management of progressive empyema in neonates is still at the stage of antimicrobial therapy and tube thoracostomy. Here, we report a 1-month-old infant with staphylococcal pneumonia complicated with multiloculated empyema who was successfully treated with video-assisted thoracoscopic surgery (VATS) after 4 days of chest tube drainage and parenteral antibiotics. The patient's condition improved rapidly after the operation and the antimicrobial therapy was continued for 3 weeks. He was asymptomatic and thriving at follow-up 1 year later. Chest radiography at 1 month was free of any lesion. This case suggests that VATS can be a safe and effective treatment for neonatal empyema.

Effects of short interfering RNA against methicillin-resistant Staphylococcus aureus coagulase in vitro and in vivo

OBJECTIVES

The emergence of antibiotic-resistant bacteria such as Staphylococcus aureus calls for inventive research and development strategies. Inhibition of bacterial pathogenesis may be a promising therapeutic approach in this regard. The gene-silencing effect of short interfering RNA (siRNA) is useful for this strategy. We investigated the efficacy of siRNA on the expression of coagulase because it is the one of the most important enzymes in the pathogenesis of methicillin-resistant S. aureus (MRSA) infection.

METHODS

We designed and synthesized 21 bp siRNA duplexes against staphylococcal coagulase. RT-PCR was performed to determine whether the siRNAs inhibit the expression of the coagulase mRNA and radio-labelled siRNA was used to confirm transfection to bacteria in vitro. The efficacy of siRNA was determined in a murine model of haematogenous pulmonary infection.

RESULTS

RT-PCR showed that siRNAs significantly inhibited the expression of the coagulase mRNA. The coagulase titres in the siRNA and control groups were 8 and 32, respectively. Measurement of incorporated radioactivity indicated that the siRNAs were delivered into the bacteria. In the murine infection model, in control and siRNA groups, 7.64 +/- 0.42 and 6.29 +/- 0.23 log cfu/mL (mean +/- SEM) MRSA were detected, respectively, showing that there was a significant decrease in the number of viable bacteria in the siRNA group (P < 0.05).

CONCLUSIONS

The results show that siRNA inhibited both mRNA expression and the activity of MRSA coagulase in vitro. The in vivo results revealed that the siRNA was effective in reducing the bacterial load in a murine model of haematogenous pulmonary infection. Targeting of coagulase with siRNA appears to be a novel strategy for treating MRSA infections.

Abszedierende Pneumonie bei einer nierentransplantierten Patientin

A 39-year old female patient who was kidney transplanted three years ago was admitted to hospital with fever of unknown origin for several days. Blood samples revealed decreased renal function and increased inflammation parameters. Chest X-ray and CT scan showed multiple cavernous structures, some with liquid. Staphylococcus aureus was detected in blood culture samples. With the aid of these results Staphylococcus pneumonia with multiple abscesses was diagnosed. The treatment consisted of removal of the infectious focus and a systemic antibiotic therapy corresponding to the microbiologic results. We describe a case of Staphylococcus pneumonia caused by a infected vascular prosthesis under consideration of immunosuppression in a renal transplanted patient.

Intrafamilial spread of highly virulent staphylococcus aureus strains carrying the gene for Panton-Valentine leukocidin

Necrotizing pneumonia caused by Staphylococcus aureus carrying the gene for Panton-Valentine leukocidin is a newly described disease entity. We report 2 cases with intrafamilial spread.

Moderate-dose intravenous immunoglobulin treatment of Job's syndrome. Case report

Job's syndrome (or hyperimmunoglobulinemia E syndrome) is a rare genetic disease characterized by skin eczema, pyogenic "cold" abscesses, sinopulmonary recidivous infections and high IgE plasma concentrations. Job's syndrome treatment is not satisfactory and cases studied are still limited. To describe the effects of IVIG therapy in a 37-year-old woman with hyper IgE syndrome and pneumonia. We measured IgE serum by immuno-fluorometric test and neutrophil chemotaxis by migration in a Boyden chamber before and after IVIG therapy. A moderate dose of IVIG resolved the clinical-radiological signs of the S. aureus bronchopneumonia and improved cytologic and biohumoral parameters. Intravenous immunoglobulins represent a useful treatment for acute pneumonia in Job's syndrome.

Primary staphylococcal pneumonia in young children: a review of 100 cases

Staphylococcus aureus (S. aureus) is responsible for a small proportion of acute respiratory infections in children. Nevertheless a high index of suspicion is required because of the potential for rapid progression, the need for antibiotics different to those routinely administered in the treatment of pneumonia, and the high incidence of complications. There are few data from developing countries. The objective of this retrospective review was to document the natural history of primary staphylococcal pneumonia at Red Cross Childrens' Hospital in Cape Town over a 7-year period (1989-1995). Staphylococcal pneumonia was defined as acute pneumonia with microbiological evidence of S. aureus or with characteristic radiological features. One hundred patients were identified. The median age was 5 months, 78 patients being below one year of age. Cough and fever were present in almost all patients at the time of presentation. Tachypnoea, recession, dullness, and crepitations were commonly elicited signs. Initial chest radiographs revealed empyema, pleural effusion, or pyopneumothorax in 67 patients. A further 26 patients developed such changes on subsequent chest radiographs. Pneumatocoeles were identified in 37 patients--most of these were only noted on radiographs taken some days after admission. Microbiological confirmation was obtained in 92 cases. S. aureus was isolated in 23/98 blood cultures, 62/67 pleural aspirates, and from tracheal aspirates in 16 cases. Intercostal drains were inserted in 67 cases and 20 children underwent thoracotomy. The case fatality rate was 7 per cent. This study shows that primary staphylococcal pneumonia is chiefly a disease of infants. Symptoms and signs were similar as for other forms of acute pneumonia, although in the majority of cases chest radiographs taken at the time of admission suggested the diagnosis. Treatment with antibiotics and drainage of empyema resulted in a good outcome in the majority of cases.

Passive local immunotherapy of experimental staphylococcal pneumonia with human intravenous immunoglobulin

Staphylococcus aureus remains a life-threatening agent of nosocomial pneumonia in immunocompromised patients. The increasing incidence of strains exhibiting wide-spectrum resistance to antibiotics, such as methicillin-resistant S. aureus (MRSA), requires new therapeutic strategies. There is renewed interest in passive immunization with human plasma-derived immunoglobulins (IVIG) as antiinfective agents. The efficacy of IVIG was tested in an experimental model of staphylococcal pneumonia, using both an MRSA clinical isolate and reference strain Cowan III, in mice immunosuppressed with cyclophosphamide. Efficient antistaphylococcal activities were obtained with IVIG administered intravenously or intranasally. IVIG saturated with protein A or its F(ab')2 fragments were as efficient as intact IVIG, suggesting that protection did not require opsonization through IgG Fc-phagocyte Fc gamma-receptor interactions. Thus, topical administration of IVIG may replace a local antibody response to S. aureus in an immunocompromised host and may be useful in prophylaxis and treatment of nosocomial S. aureus pneumonia.

[Treatment of severe pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA) and Candida krusei with granulocyte colony-stimulating factor (G-CSF): a case report]

A 24-year-old male with chronic renal failure on Continuous Ambulatory Peritoneal Dialysis (CAPD) complained of cough and dyspnea. Chest X-ray film showed a pneumonia shadow and MRSA and Candida krusei were detected in the sputum. Pneumonia improved with vancomycin and fluconazole. Treatment with methylprednisolone was needed for retinodialysis. After this treatment, pneumonia deteriorated. Pneumonia did not improve with vancomycin and anti-fungal agents. This severe pneumonia was improved with a combination therapy of vancomycin, miconazole and G-CSF. A combination therapy of antibiotics and G-CSF is considered to be effective for severe pneumonia.

Pneumatoceles and pneumothoraces complicating staphylococcal pneumonia: treatment by synchronous independent lung ventilation

A 54 year old man with a staphylococcal sepsis developed staphylococcal pneumonia complicated by multiple pneumatoceles and bilateral tension pneumothoraces caused by bronchopleural fistulae. Excessive enlargement of the right sided pneumatoceles and a tension pneumothorax not improved by drainage led to mediastinal shift and compression of the right lung. Reversal of the mediastinal shift and closure of the bronchopleural fistulae was achieved by assisted independent lung ventilation.

Primary staphylococcal pneumonia in childhood: a review of 69 cases

Primary staphylococcal pneumonia is a rapidly progressive illness with well-described clinical and radiological features and a significant mortality rate. This retrospective study of cases diagnosed over a 20 year period at a tertiary paediatric hospital was undertaken to document the epidemiology and assess the management and mortality of the disease. The survey demonstrated that far fewer patients are being seen than formerly and confirmed that this is a disease primarily affecting infants and Aboriginal children. The initial radiological features were not diagnostic in the majority of cases but typical changes appeared in most at some time during the illness. The use of surgical drainage was not associated with a decrease in the duration of fever or length of hospital stay. The mortality rate has improved but remains significant.

[Toxic shock syndrome in a 6-year-old male]

Toxic shock syndrome, caused by an exotoxin of staphylococcus aureus is very rare in children. On admission, beside the shock, abdominal problems as vomiting, diarrhoea and a developing adynamic ileus were outstanding in our patient. Not before additional symptoms as staphylococcal pneumonia with bacteriemia occurred and later desquamation of palms and feet, diagnosis of toxic shock syndrome could be confirmed.

[Clinical aspects of septic lesions of the lungs]

Clinicoroentgenological variants of pulmonary complications were revealed in 96 (81%) out of 118 sepsis patients. In 55% of cases the disease emerged due to staphylococcal infection. Sepsis lesions of the lungs were analyzed clinically and classified according to respiratory insufficiency. The treatment oriented on pulmonary sepsis resulted in lowering of mortality (up to 17%). Measures to improve early diagnosis and to promote intensive treatment are under discussion.

The incidence and significance of Staphylococcus aureus in respiratory cultures from patients infected with the human immunodeficiency virus

This study assessed the incidence and clinical significance of recovery of Staphylococcus aureus from the respiratory tract of patients infected with the human immunodeficiency virus (HIV). In a retrospective review of 129 consecutive episodes of respiratory disease in HIV-seropositive patients where respiratory tract cultures were obtained, S. aureus was recovered in 30 (23%) of the episodes. Twenty-nine of these were evaluated in this study, and the recovery of S. aureus was found to represent pneumonia in 8 cases (28%), to be of indeterminate significance in 18 cases (62%), and to represent colonization in 3 cases (10%). Episodes of S. aureus pneumonia were usually community-acquired (seven of eight episodes) and had an acute or subacute clinical presentation. Fever and physical signs of pneumonia were present in all patients. Chest radiographic presentations varied, but local infiltrates were seen in seven of eight episodes. Concomitant pulmonary disorders were common (seven of eight episodes). All patients were appropriately treated; five patients recovered and three died, giving a mortality rate of 38%. We conclude that S. aureus is a frequent isolate from respiratory tract cultures of HIV-seropositive patients referred for evaluation of pulmonary disease. It can cause a pneumonia with a high mortality rate, as it did in 6% of all episodes of pulmonary disease reviewed in this study. Clinicians should be aware that HIV-seropositive patients may develop respiratory disease secondary to S. aureus infection and that when this organism is suspected, appropriate antibiotic therapy should be instituted.

[Clinical problems of staphylococcal septicemia]

Clinical Problems in staphylococcal septicaemia are reported in the observed 13 cases with severe multiorgan complications. In 69.2% of patients the course of the disease was very serious or severe, in the remaining cases it was moderately severe. Attention is called to the variety of clinical patterns and to frequent involvement of the central nervous system, cardiovascular system and respiratory system during septicaemia. The therapeutic management included, besides combined treatment with three antibiotics of synergistic action, antistaphylococcal serum, glucocorticoids, agents increasing the general resistance of the organism (transfusion of fresh blood, gamma-vein, gammaglobulin), cardiac drugs and symptomatic drugs, and in some cases cytochrome and heparin. Particular attention was given to adequate nursing care. Two patients died (15.4%).

[Septic metastatic staphylococcal destruction of the lungs in adults]

The author analyzes results of diagnostics and treatment of 152 patients with septic metastatic staphylococcal destruction of the lungs. Specific features of the clinical course of the disease are described. Under consideration are questions of the complex pathogenetic treatment of this group of patients by means of using antibiotic and immune therapy, fat emulsions (lipofundin), exchange plasmapheresis, ultraviolet irradiation of blood etc.