The management of infection and colonization due to methicillin-resistant Staphylococcus aureus: A CIDS/CAMM position paper.

Methicillin-resistant Staphylococcus aureus (MRSA) is being seen with greater frequency in most hospitals and other health care facilities across Canada. The organism may cause life-threatening infections and has been associated with institutional outbreaks. Several studies have confirmed that MRSA infection is associated with increased morbidity and mortality compared with infections caused by susceptible strains, even when the presence of comorbidities is accounted for. Treatment of MRSA infection is complicated by the fact that these organisms are resistant to multiple antimicrobial agents, so treatment options are limited. The effectiveness of decolonization therapy (attempting to eradicate MRSA carriage) is also uncertain. This paper reviews the medical management of MRSA infections, discusses the potential role of decolonization and provides an overview of evidence to support recommended infection control practices.     

Pulmonary infection due to methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) are now causing severe clinical infection on a worldwide basis. Pulmonary infection due to MRSA although widely reported is poorly documented. We report the predisposing factors, underlying diseases, treatment and outcome in 4 patients with pneumonia, 3 patients with empyema thoracis, 1 patient with pneumonia and empyema thoracis, 1 patient with pneumonia plus lobectomy wound infection and 2 patients with lung abscess. Vancomycin was highly effective in treatment, a finding compatible with experience treating other severe MRSA infections.     

Clindamycin for colonization and infection by methicillin-resistant Staphylococcus aureus

Summary Effective antimicrobial therapy for infection or colonization by methicillin-resistantStaphylococcus aureus (MRSA) is very limited. In some institutions, the majority of strains remain susceptible to clindamycinin vitro. We report five patients with colonization or infection of varying severity caused by MRSA who had the organism successfully eradicated by clindamycin. In one patient who had an MRSA infection that persisted during vancomycin therapy clindamycin therapy was able to finally eradicate the organism. Clindamycin should be seriously considered as alternative therapy for colonization or infection by MRSA.

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Beseitigung der Kolonisation und Infektion durch methicillinresistente Staphylococcus aureus mit Clindamycin

Zusammenfassung Für die Behandlung der Infektion oder Beseitigung der Kolonisation durch methicillinresistenteStaphylococcus aureus-Stämme stehen nur wenige wirksame antimikrobielle Substanzen zur Verfügung. In manchen Kliniken sind die Stämme überwiegend gegen Clindamycin empfindlich geblieben. Wir berichten über fünf Patienten, bei denen es mit Clindamycin gelang, Infektionen verschiedener Schweregrade durch methicillinresistenteS. aureus und auch die Kolonisation mit diesen Stämmen zu beseitigen. Bei einem Patienten mit persistierender Infektion durch methicillinresistente Staphylokokken nach Vancomycin-Behandlung konnte der Erreger schließlich mit Clindamycin ausgerottet werden. Clindamycin sollte sehr ernsthaft als Alternativtherapeutikum für Fälle von Kolonisation oder Infektion durch methicillinresistente Staphylokokken in Erwägung gezogen werden.

     

Prostatic abscess due to community-acquired methicillin-resistant Staphylococcus aureus

We report what we believe to be the second case of a prostatic abscess due to community-acquired methicillin-resistant Staphylococcus aureus (MRSA). A previously healthy diabetic man presented with dysuria, fatigue, weight loss, a tender prostate, and leukocytosis. Computerized tomography of the abdomen and pelvis demonstrated a large prostatic abscess at the base of the bladder. Blood, urine, and pus obtained by percutaneous aspiration grew MRSA. Percutaneous drainage and prolonged therapy with intravenous vancomycin resulted in cure. Prostatic abscess is most often caused by Gram-negative organisms. Community-acquired MRSA, which usually causes skin and soft tissue infections, may also cause prostatic abscess. The mainstay of treatment of prostatic abscess is drainage, which can be accomplished either percutaneously or transurethrally. Gram stain and culture of the drainage will direct proper antibiotic selection.     

Evaluation of intraspecies interference due to agr polymorphism in Staphylococcus aureus during infection and colonization

In Staphylococcus aureus infection, intraspecies cross-inhibition mediated by the regulatory system agr may lead to the exclusion of heterologous strains at the site of infection or colonization. We analyzed consecutive and cocolonizing strains (classified as different clones by pulsed-field gel electrophoresis) from patients with cystic fibrosis (CF) and healthy individuals. Strain replacement was accompanied by a change in the agr group in 80% of the patients with CF and in 63% of the healthy individuals. Cocolonizing strains from patients with CF were shown to belong to interfering agr groups in 6 of 10 cases. In contrast, in healthy individuals, cocolonization of the nares with strains of interfering agr groups was rarely observed. agr polymorphism has no impact on the colonization dynamics of S. aureus in patients with CF but may influence nasal colonization in health individuals.     

社区获得性耐甲氧西林金黄色葡萄球菌肺炎临床分析

目的 探讨社区获得性耐甲氧西林金黄色葡萄球菌肺炎的临床特点.方法 对16例确诊病例的临床资料进行回顾性研究.结果 16例确诊病例,13例无基础性疾病,9例合并休克,7例合并急性呼吸窘迫综合征,4例死亡；死亡者从出现症状入院至死亡平均时间为(5.9±6.1)d,生存者平均住院时间为(21.6±11.1)d；8例有流感样症状,7例有咯血,5例有白细胞减少,16例C-反应蛋白明显升高,平均为(211.1±121.9) mg/L,13例有多肺叶病变,9例有胸腔积液.结论 社区获得性耐甲氧西林金黄色葡萄球菌肺炎病情凶险,应提高对其临床特点的认识,优化综合治疗方案.     

Contribution of nasal methicillin-resistant Staphylococcus aureus colonization to percutaneous endoscopic gastrostomy site infection and risk factors of wound infection]

BACKGROUND/AIMS: Peristomal infection is the most common complication of percutaneous endoscopic gastrostomy (PEG) insertion. Methicillin-resistant Staphylococcus aureus (MRSA) is the most commonly implicated organism of peristomal infection. The aims of this study were to determine the contribution of nasal MRSA to wound infection in PEG and the predictors of wound infection. METHODS: A prospective study was conducted on patients undergoing PEG between September 2003 and July 2005. All patients received antibiotics prior to PEG insertion. Nasal swabs were taken from a consecutive series of patients prior to PEG insertion. Wound status of the peristomal site were prospectively evaluated at day 1, 3, and 7 following the insertion of PEG. RESULTS: Thirty-one patients underwent PEG insertion (mean age, 66+/-16 years). Ten patients (32.3%) had MRSA-positive nasal swabs. Peristomal infection did not have any relationship with nasal MRSA colonization (p>0.05). Peristomal infection occurred in 4 (12.9%) cases. The rate of peristomal infections was significantly higher in patients with diabetes mellitus (p<0.05). CONCLUSIONS: Nasal MRSA colonization is not associated with the risk of peristomal infections in patients receiving antibiotics prior to PEG insertion. Diabetes mellitus might be the risk factor for peristomal infection after PEG insertion.     

Purulent pericarditis due to methicillin-resistant Staphylococcus aureus. A case report.

Purulent pericarditis is an infrequent complication of infections originating in another body location. Symptoms and signs are often absent; a high index of awareness is required for its diagnosis. A patient recovering from extensive necrotic-hemorrhagic pancreatitis presented with tamponade due to methicillin-resistant Staphylococcus aureus (MRSA) purulent pericarditis, further complicated by MRSA endocarditis. Treatment included pericardectomy, IV vancomycin and teicoplanin.     

Study of methicillin-resistant Staphylococcus aureus colonization among intermediate-care facility patients

PURPOSE: Prevalence of methicillin-resistant Staphylococcus aureus is high in the Poitiers teaching hospital, particularly in the intermediate care facilities. We performed a survey of methicillin-resistant Staphylococcus aureus colonization in the intermediate care facilities and 265 patients were included. METHODS: Nasal, cutaneous and wound swab cultures were done at the time of admission and at the time of the patients' departure. A decolonization procedure of methicillin-resistant Staphylococcus aureus carriers was performed using nasal application of fusidic acid and different soaps for the skin. At entry, 17.7% of patients were methicillin-resistant Staphylococcus aureus carriers (of at least one location). At departure, 30.4% were methicillin-resistant Staphylococcus aureus carriers. Among methicillin-resistant Staphylococcus aureus non-carriers at entry, 24.3% became methicillin-resistant Staphylococcus aureus carriers. RESULTS: The principal risk factor of carriage was the initial presence of a wound (RR = 3.6). The incidence rate of methicillin-resistant Staphylococcus aureus infection among the 265 patients included was 3%. CONCLUSION: The systematic screening of patients at the time of admission is expensive and isolation technically hard to manage in the intermediate care facilities. The risk factor we found in this study allow us to propose a 'light' screening limited to patients with wounds.     

Persistent methicillin-resistant Staphylococcus aureus bacteremia due to a prostatic abscess

This report describes a patient with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia secondary to a prostatic abscess. The literature describing complications of S. aureus bacteremia and the bacteriology of prostatic abscesses is reviewed. This was found to be the first report of a patient with persistent MRSA bacteremia maintained by a prostatic focus.     

Antibody-mediated enhancement of community-acquired methicillin-resistant Staphylococcus aureus infection

Community-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) expressing the Panton-Valentine leukocidin (PVL) are rampant, but the contribution of PVL to bacterial virulence remains controversial. While PVL is usually viewed as a cytotoxin, at sublytic amounts it activates protective innate immune responses. A leukotoxic effect might predominate in high inoculum studies, whereas protective proinflammatory properties might predominate in settings with lower bacterial inocula that more closely mimic what initially occurs in humans. However, these protective effects might possibly be neutralized by antibodies to PVL, which are found in normal human sera and at increased levels following PVL⁺ S. aureus infections. In a low-inoculum murine skin abscess model including a foreign body at the infection site, strains deleted for the pvl genes replicated more efficiently within abscesses than isogenic PVL⁺ strains. Coinfection of mice at separate sites with isogenic PVL⁺ and PVL^- MRSA abrogated the differences in bacterial burdens, indicating a systemic effect on host innate immunity from production of PVL. Mice given antibody to PVL and then infected with seven different PVL⁺ strains also had significantly higher bacterial counts in abscesses compared with mice given nonimmune serum. Antibody to PVL had no effect on MRSA strains that did not produce PVL. In vitro, antibody to PVL incapacitated PVL-mediated activation of PMNs, indicating that virulence of PVL⁺ MRSA is enhanced by the interference of PVL-activated innate immune responses. Given the high rates of primary and recurring MRSA infections in humans, it appears that antibodies to PVL might contribute to host susceptibility to infection.