Staphylococcus aureus bacteremia among elderly vs younger adult patients: comparison of clinical features and mortality.

BACKGROUND: Previous studies give conflicting results regarding the effect of age on outcomes in Staphylococcus aureus bacteremia (SAB). These studies have been limited by retrospective design or small sample size. METHODS: We conducted a prospective cohort study of 385 patients with SAB aged 18 to 90 years. The setting was a large academic medical center. We observed patients from diagnosis of SAB to discharge or death. Discharged patients were contacted 12 weeks after their first positive culture findings. Data were collected on demographics, comorbid conditions, focus of infection, length of stay, and outcome. Primary outcomes were total mortality and death due to SAB. RESULTS: Comparisons were made between 145 patients, aged 66 to 90 years, and 240 patients, aged 18 to 60 years. Forty-three (29.7%) of the elderly patients and 36 (15%) of the younger patients died. Death directly attributable to SAB occurred in 21 (14.5%) older and 15 (6.3%) younger patients. After adjusting for confounding variables, older patients continued to have higher total mortality (odds ratio, 2.21; 95% confidence interval, 1.32-3.70), and higher mortality from SAB (odds ratio, 2.30; 95% confidence interval, 1.13-4.69). Infection with methicillin-resistant S aureus was associated with higher total mortality in the elderly (odds ratio, 2.59; 95% confidence interval, 1.23-5.43). CONCLUSIONS: Staphylococcus aureus bacteremia among the elderly is associated with high mortality. Both total mortality and mortality directly attributable to SAB are more than twice as likely in older patients. Infection with methicillin-resistant S aureus carries a worse prognosis than infection with methicillin-sensitive S aureus in the elderly.     

Treatment of community-acquired methicillin-resistant Staphylococcus aureus in children

PURPOSE OF REVIEW: The concept of methicillin-resistant Staphylococcus aureus (MRSA) associated with broad resistance, nosocomial acquisition, and known risk factors has recently been expanded. A new type of MRSA that is resistant to fewer antibiotics has emerged in pediatric practice since the mid-1990s. These isolates are community acquired and have been reported from diverse geographic regions. Awareness of these organisms is important for appropriate treatment of S. aureus infections in children. RECENT FINDINGS: Community-acquired MRSA (CA-MRSA) isolates are similar in many respects to community-acquired methicillin-susceptible S. aureus (CA-MSSA). There are usually no differences in risk factors between children with CA-MRSA infections and those with CA-MSSA infections or their household contacts. In one study, however, multivariate analysis showed that age greater than 1 year and health care contact in the preceding month were significant risk factors for CA-MRSA. Skin and soft tissue infections are the most common manifestations, although serious invasive infections and death may occur. Pneumonia has been reported more often in children with CA-MRSA than in those with CA-MSSA. Clindamycin is an effective therapy for CA-MRSA, but there is a risk for development of clindamycin resistance during treatment of a CA-MRSA that is clindamycin susceptible and inducibly erythromycin resistant. Trimethoprim-sulfamethoxazole is likely to be effective, and linezolid is a new option for treatment. SUMMARY: The appearance of CA-MRSA has important implications for therapy of infections caused by S. aureus in children. Three specific issues are the development of resistance during clindamycin therapy, insufficient data on the use of trimethoprim-sulfamethoxazole in serious CA-MRSA infections, and the appropriate role for newer antibiotics such as linezolid.     

Staphylococcus aureus bacteremia. Clinical, serologic, and echocardiographic findings in patients with and without endocarditis

Seventy-two adult patients with Staphylococcus aureus bacteremia were prospectively studied clinically, serologically, and echocardiographically. Multivariate analysis identified four parameters that significantly predicted endocarditis in staphylococcemic patients at time of initial evaluation: absence of a primary site of infection; community acquisition of infection; metastatic sequelae; and valvular vegetations detected by echocardiography. Echocardiography was most predictive of endocarditis in patients with community-acquired S aureus bacteremia from an obvious primary focus. In 11 (69%) of 16 patients with endocarditis and vegetations on two-dimensional echocardiography, this technique also revealed other important findings, including ventricular dilatation, and/or underlying valvular lesions. In 18% of patients with S aureus bacteremia without stigmata of endocarditis, echocardiography provided information that led to a diagnosis of endocarditis and a subsequent change in therapy. Our findings support the routine use of two-dimensional echocardiography in all cases of community-acquired S aureus bacteremia to identify occult endocarditis in patients without classic stigmata of disease, and to provide important prognostic data in clinically apparent endocarditis.     

A prospective multicenter study of Staphylococcus aureus bacteremia: incidence of endocarditis, risk factors for mortality, and clinical impact of methicillin resistance

Our objectives were to determine the incidence of endocarditis in patients whose Staphylococcus aureus bacteremia was community-acquired, related to hemodialysis, or hospital-acquired; to assess clinical factors that would reliably distinguished between S. aureus bacteremia and S. aureus endocarditis; to assess the emergence of methicillin-resistant S. aureus (MRSA) as a cause of endocarditis; and to examine risk factors for mortality in patients with S. aureus endocarditis.We conducted a prospective observational study in 6 university teaching hospitals; we evaluated 505 consecutive patients with Staphylococcus aureus bacteremia. Thirteen percent of patients with S. aureus bacteremia were found to have endocarditis, including 21% with community-acquired S. aureus bacteremia, 5% with hospital-acquired bacteremia, and 12% on hemodialysis. Infection was due to MRSA in 31%.Factors predictive of endocarditis included underlying valvular heart disease, history of prior endocarditis, intravenous drug use, community acquisition of bacteremia, and an unrecognized source. Twelve patients with bacteremia had a prosthetic valve; 17% developed endocarditis. Unexpectedly, nonwhite race proved to be an independent risk factor for endocarditis by both univariate and multivariate analyses. Persistent bacteremia (positive blood cultures at day 3 of appropriate therapy) was identified as an independent risk factor for both endocarditis and mortality, a unique observation not reported in other prospective studies of S. aureus bacteremia.Patients with endocarditis due to MRSA were significantly more likely to have complicating renal insufficiency and to experience persistent bacteremia than those with endocarditis due to MSSA. The 30-day mortality was 31% among patients with endocarditis compared to 21% in patients who had bacteremia without endocarditis (p = 0.055). Risk factors for death due to endocarditis included severity of illness at onset of bacteremia (as measured by Apache III and Pitt bacteremia score), MRSA infection, and presence of atrioventricular block on electrocardiogram.Patients with S. aureus bacteremia who have community acquisition of infection, underlying valvular heart disease, intravenous drug use, unknown portal of entry, history of prior endocarditis, and possibly, nonwhite race should undergo echocardiography to screen for the presence of endocarditis. We recommend that blood cultures be repeated 3 days following initiation of antistaphylococcal antibiotic therapy in all patients with S. aureus bacteremia. Positive blood cultures at 3 days may prove to be a useful marker in promoting more aggressive management, including more potent antibiotic therapy and surgical resection of the valve in endocarditis cases. MRSA as the infecting organism should be added to the list of risk factors for consideration of valvular resection in cases of endocarditis.     

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.     

Cavernous sinus thrombosis and meningitis from community-acquired methicillin-resistant Staphylococcus aureus infection

Septic cavernous sinus thrombosis is an uncommon clinical syndrome with a high morbidity and mortality. The commonest bacterial pathogen is Staphylococcus aureus. We describe the study of a patient with cavernous sinus thrombosis and meningitis caused by community-acquired methicillin-resistant S. aureus (CA-MRSA) infection. The isolate was genotyped as the ST93 (Queensland) clone of CA-MRSA and carried the Panton-Valentine leucocidin genes. Cure was obtained following prolonged antimicrobial therapy with vancomycin, rifampicin, cotrimoxazole and linezolid. Given the high morbidity and mortality of cavernous sinus thrombosis and the worldwide recent emergence of CA-MRSA, clinicians treating patients with this infection should consider early empirical coverage for CA-MRSA with an antimicrobial agent, such as vancomycin or linezolid, particularly in the presence of suspected facial staphylococcal skin infections. If vancomycin is used, we emphasize that high doses may be required to achieve even low levels in the cerebrospinal fluid.     

Recurrent Staphylococcus aureus bacteremia: pulsed-field gel electrophoresis findings in 29 patients

To identify risk factors for relapse among 309 prospectively identified cases of Staphylococcus aureus bacteremia, patients with recurrent S. aureus bacteremia were identified, and pulsed-field gel electrophoresis (PFGE) was performed on isolates from both episodes. PFGE banding patterns from both isolates were identical in 23 patients, consistent with relapsed infection. Patients with PFGE-confirmed relapse were more likely by both univariate and multivariate analyses to have an indwelling foreign body (odds ratio [OR]=18.2, 95% confidence interval [CI]=7. 6-43.6; P<.001), to have received vancomycin therapy (OR=4.1, 95% CI=1.5-11.6; P=.008), or be hemodialysis-dependent (OR=4.1, 95% CI=1. 8-9.3; P=.002) than patients who did not develop recurrent bacteremia. These results suggest that recurrent episodes of S. aureus bacteremia are primarily relapses and are associated with an indwelling foreign body, receiving vancomycin therapy, and hemodialysis dependence.     

Clinical characteristics and outcome of aortic endocarditis with periannular abscess in the International Collaboration on Endocarditis Merged Database

The aims of this study were to determine the clinical characteristics and outcome of patients who had definite infective endocarditis (IE) complicated by aortic ring abscess formation that was detected with transesophageal echocardiography (TEE) and to determine the prognostic significance of abscess formation in aortic valve IE. Patients who had aortic valve IE were selected from the International Collaboration on Endocarditis Merged Database (ICE-MD) if they underwent TEE. Among 311 patients who had definite aortic valve IE, 67 (22%) had periannular abscesses. They were more likely to have infection in the setting of a prosthetic valve (40% vs 19%, p <0.001) and coagulase-negative staphylococcal IE (18% vs 6%, p < 0.01) and less likely to have streptococcal IE than were patients who did not develop abscess (28% vs 46%, p = 0.01). Systemic embolization, central nervous system events, and heart failure did not differ between those who developed abscess and those who did not, but power was limited. Patients who had abscess were more likely to undergo surgery (84% vs 36%, p <0.001), and their in-hospital mortality rate was higher (19% vs 11%, p = 0.09). Multivariate analysis of prognostic factors of mortality in aortic IE identified age (odds ratio [OR] 1.6, 95% confidence interval [CI]1.2 to 2.1), Staphylococcus aureus (S. aureus) infection (OR 2.4, 95% CI 1.1 to 5.2), and heart failure (OR 2.9, 95% CI 1.4 to 6.1) as variables that were independently associated with increased risk of death. Periannular abscess formation showed a nonsignificant trend toward an increased risk of death (OR 1.9, 95% CI 0.9 to 3.8). Multivariate analysis of prognostic factors of mortality in complicated aortic IE with abscess formation identified S. aureus infection (OR 6.9, 95% CI 1.6 to 29.4) as independently associated with increased risk of death. In conclusion, in the current era of TEE and high use of surgical treatment, periannular abscess formation in aortic valve IE is not an independent risk factor for mortality. S. aureus infection is an independent prognostic factor for mortality in patients who have abscess formation.     

Outcome and attributable mortality in critically Ill patients with bacteremia involving methicillin-susceptible and methicillin-resistant Staphylococcus aureus

BACKGROUND: Staphylococcus aureus bacteremia carries high mortality rates. The clinical impact of methicillin resistance remains controversial: outcome comparisons between patients with bacteremia involving methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) S aureus are difficult to perform because of important differences in severity of illness. METHODS: A retrospective cohort analysis and 2 independent case-control analyses were performed to determine and compare outcomes and attributable mortality rates of MSSA (n = 38) and MRSA bacteremia (n = 47) in critically ill patients. For the case-control studies, matching (1:2 ratio) was based on the APACHE (Acute Physiology and Chronic Health Evaluation) II classification: APACHE II score (+/-1 point) and diagnostic category. RESULTS: Patients with MRSA bacteremia had more acute renal failure and hemodynamic instability than patients with MSSA bacteremia. They had a longer intensive care unit stay and ventilator dependency. Patients with MRSA bacteremia had a higher 30-day mortality rate (53.2% vs 18.4%) and in-hospital mortality rate (63.8% vs 23.7%) (P<.05). Multivariate survival analysis demonstrated acute renal failure, length of mechanical ventilation, age, and methicillin resistance to be independently associated with mortality (P<.05). The attributable mortality rate for MSSA bacteremia was 1.3%: mortality rates for cases and controls were respectively 23.7% and 22.4% (P =.94). The attributable mortality rate for MRSA bacteremia was 23.4%: mortality rates for cases and controls were respectively 63.8% and 40.4% (P =.02). The difference (22.1%) between both attributable mortality rates was significant (95% confidence interval, 8.8%-35.3%). CONCLUSION: In critically ill patients, after accurate adjustment for disease severity and acute illness, we found MRSA bacteremia to have a higher attributable mortality than MSSA bacteremia.     

Community-associated methicillin-resistant Staphylococcus aureus skin and soft tissue infections at a public hospital: do public housing and incarceration amplify transmission?

BACKGROUND: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections have emerged among patients without health care-associated risk factors. Understanding the epidemiology of CA-MRSA is critical for developing control measures. METHODS: At a 464-bed public hospital in Chicago and its more than 100 associated clinics, surveillance of soft tissue, abscess fluid, joint fluid, and bone cultures for S aureus was performed. We estimated rates of infection and geographic and other risks for CA-MRSA through laboratory-based surveillance and a case-control study. RESULTS: The incidence of CA-MRSA skin and soft tissue infections increased from 24.0 cases per 100,000 people in 2000 to 164.2 cases per 100,000 people in 2005 (relative risk, 6.84 [2005 vs 2000]). Risk factors were incarceration (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.00-3.67), African American race/ethnicity (OR, 1.91; 95% CI, 1.28-2.87), and residence at a group of geographically proximate public housing complexes (OR, 2.50; 95% CI, 1.25-4.98); older age was inversely related (OR, 0.89; 95% CI, 0.82-0.96 [for each decade increase]). Of 73 strains tested, 79% were pulsed-field gel electrophoresis type USA300. CONCLUSIONS: Clonal CA-MRSA infection has emerged among Chicago's urban poor. It has occurred in addition to, not in place of, methicillin-susceptible S aureus infection. Epidemiological analysis suggests that control measures could focus initially on core groups that have contributed disproportionately to risk, although CA-MRSA becomes endemic as it disseminates within communities.     

Staphylococcus aureus pneumonia: emergence of MRSA in the community

The clinical presentation of staphylococcal pneumonia is changing. Healthy young people without traditional risk factors for Staphylococcus aureus disease are presenting with severe necrotizing infection and high mortality. The clinical picture is reminiscent of outbreaks of postinfluenzal staphylococcal pneumonia seen in the past century. Most of these staphylococcal strains are methicillin-resistant and are not health care associated. Many strains contain toxins that are likely responsible for the severity of illness seen. Panton-Valentine leukocidin has rarely been identified in S. aureus until recently. It appears that the genetic element for methicillin resistance has been introduced into multiple highly virulent methicillin-susceptible strains with great potential for further spread. Early recognition and treatment of possible community-acquired methicillin-resistant S. aureus (CA-MRSA) is essential. It is equally important to attain microbiological confirmation of the diagnosis for optimal treatment and to initiate appropriate infection control procedures.     

Risk factors and clinical outcomes of multidrug-resistant Acinetobacter baumannii bacteremia at a university hospital in Thailand

Multidrug-resistant (MDR) Acinetobacter baumannii has become a major cause of hospital-acquired infection worldwide. There are few papers regarding this particular subject. Our aim was to assess the incidence of bacteremia due to MDR Acinetobacter baumannii, factors associated with the infection, and clinical outcomes. We studied 49 cases of A. baumannii bacteremia in adult patients admitted to a university hospital in Northeast Thailand between 2005 and 2007. The incidence of MDR A. baumannii bacteremia was 3.6 episodes per 10,000 hospital admissions. Significantly independent factors associated with MDR A. baumannii bacteremia were previous: 1) ICU admission [odds ratio (OR) 10.01; 95% confidence interval (CI) 1.39-72.20]; 2) use of beta-lactam/beta-lactamase inhibitor antibiotics (OR 8.06; 95%CI 1.39-46.64); and 3) use of a carbapenem antibiotics (OR 11.40; 95%CI 1.44-89.98). The overall mortality rate was significantly higher in the MDR group than in the susceptible group (91.7% vs 48%, respectively) (p=0.001). The significantly independent factors related to mortality were: 1) APACHE II score (OR 1.25; 95%CI 1.03-1.52) and 2) secondary bacteremia (OR 14.86; 95%CI 1.37-161.90). This study revealed the significantly independent factors associated with MDR A. baumannii bacteremia were prior ICU admission and prior use of broad spectrum antibiotics. This infection has a high mortality rate. Emphasis needs to be on prevention, strict application of infection control and appropriate use of antibiotics.     

Treatment and outcome of Staphylococcus aureus bacteremia: a prospective study of 278 cases.

BACKGROUND: Staphylococcus aureus bacteremia is still a serious problem, and the optimal treatment is under debate. Only a few studies concerning treatment are available. METHODS: The study population was all patients with a positive blood culture result for S aureus in Copenhagen County, Denmark, from May 1994 through April 1996. Of 278 patients with S aureus bacteremia, 186 were evaluated according to outcome in a prospective, observational follow-up study. The time above the minimum inhibitory concentration was estimated for dicloxacillin sodium for each treatment regimen and evaluated by logistic regression along with other potential risk factors. RESULTS: The following variables were statistically associated with death: the presence of an uneradicated focus (odds ratio [OR], 6.7; 95% confidence interval [CI], 2.1-21.0); the presence of septic shock (OR, 3.7; 95% CI, 1.5-9.1); the total daily dose of penicillinase-stable penicillin less than 4 g (OR, 3.7; 95% CI, 1.3-11.1); and age 60 years or older (OR, 2.4; 95% CI, 1.1-5.3). The following variables were significantly associated with recurrence: the total daily dose of penicillinase-stable penicillin less than 3 g (OR, 3.9; 95% CI, 1.6-10.0) and the presence of a secondary focus (OR, 3.2; 95% CI, 1.3-7.7). Among 155 patients with observation time longer than duration of treatment, this factor (duration of treatment, <14 days) was significantly related to mortality (OR, 0.84; 95% CI, 0.76-0.94). CONCLUSIONS: Focus eradication and the dosing of penicillinase-stable penicillin are important to the outcome of S aureus bacteremia. We recommend treatment with at least 1 g of penicillinase-stable penicillins 4 times daily for longer than 14 days.     

Hospital mortality for patients with bacteremia due to Staphylococcus aureus or Pseudomonas aeruginosa

STUDY OBJECTIVES: To evaluate the relationship between hospital mortality and bloodstream infections due to Staphylococcus aureus or Pseudomonas aeruginosa. DESIGN: Prospective cohort study. SETTING: A 1,400-bed, university-affiliated urban teaching hospital. PATIENTS: Between December 2001 and September 2002, 314 patients with bacteremia due to S aureus or P aeruginosa were prospectively evaluated. INTERVENTION: Prospective patient surveillance and data collection. RESULTS: Thirteen patients (4.1%) received inadequate initial antibiotic treatment. Fifty-four patients (17.2%) died during hospitalization. Hospital mortality was statistically greater for patients with bloodstream infections due to P aeruginosa (n = 49) compared to methicillin-sensitive S aureus (MSSA) [n = 117; 30.6% vs 16.2%, p = 0.036] and methicillin-resistant S aureus (MRSA) [n = 148; 30.6% vs 13.5%, p = 0.007]. Multiple logistic regression analysis identified the lack of response to initial medical treatment (adjusted odds ratio [AOR], 2.69; 95% confidence interval [CI], 1.83 to 3.94; p = 0.010) and endocarditis (AOR, 4.62; 95% CI, 2.45 to 8.73; p = 0.016) as independent determinants of hospital mortality. Patients with bloodstream infections due to P aeruginosa were statistically more likely to be nonresponders to early medical treatment compared to patients with MSSA (73.5% vs 11.1%, p < 0.001) and MRSA (73.5% vs 16.9%, p < 0.001) bloodstream infections. CONCLUSIONS: These data suggest that bloodstream infections due to P aeruginosa have a greater risk of hospital mortality compared to bloodstream infections due to S aureus despite adequate antibiotic treatment.     

In vitro production of panton-valentine leukocidin among strains of methicillin-resistant Staphylococcus aureus causing diverse infections.

BACKGROUND: Community-acquired methicillin-resistant Staphylococcus aureus strains have recently been associated with severe necrotizing infections. Greater than 75% of these strains carry the genes for Panton-Valentine leukocidin (PVL), suggesting that this toxin may mediate these severe infections. However, to date, studies have not provided evidence of toxin production. METHODS: Twenty-nine community-acquired methicillin-resistant Staphylococcus aureus and 2 community-acquired methicillin-susceptible S. aureus strains were collected from patients with infections of varying severity. Strains were analyzed for the presence of lukF-PV and SCCmecA type. PVL production in lukF-PV gene-positive strains was measured by ELISA, and the amount produced was analyzed relative to severity of infection. RESULTS: Only 2 of the 31 strains tested, 1 methicillin-resistant Staphylococcus aureus abscess isolate and 1 nasal carriage methicillin-susceptible S. aureus isolate, were lukF-PV negative. All methicillin-resistant Staphylococcus aureus strains were SCCmec type IV. PVL was produced by all strains harboring lukF-PV, although a marked strain-to-strain variation was observed. Twenty-six (90%) of 29 strains produced 50-350 ng/mL of PVL; the remaining strains produced PVL in excess of 500 ng/mL. The quantity of PVL produced in vitro did not correlate with severity of infection. CONCLUSIONS: Although PVL likely plays an important role in the pathogenesis of these infections, its mere presence is not solely responsible for the increased severity. Factors that up-regulate toxin synthesis in vivo could contribute to more-severe disease and worse outcomes in patients with community-acquired methicillin-resistant Staphylococcus aureus infection.     

Persistence in Staphylococcus aureus bacteremia: incidence, characteristics of patients and outcome

Staphylococcus aureus bacteremia often persists. The reasons for persistence and its outcome are poorly defined. We conducted a prospective-observational study among 245 consecutive S. aureus (MRSA: n=125; MSSA: n=120) bacteremias (>or=1 positive blood cultures (BC)) among 234 adults (18-103-y-old; median=59 y) hospitalized during 1 January 2002-31 December 2002 at a 600-bed teaching hospital. Measurements included bacteremia duration, complication-rate (metastatic infection, relapse or attributable mortality) and outcome. Bacteremia duration was measured based on follow-up BC among 193 patients and estimated based on symptoms resolution in the rest. Measured (1-59 d; median=2) and estimated (median=1 d) duration correlated (r=0.885) though positive follow-up BC was often detected without fever (57/105 patients, 54.3%). Persistence (defined as bacteremia for >or=3 d) was noted in 84 cases (38.4%). Complication-rate increased steadily with bacteremia duration (6.6%, 24.0% and 37.7% in bacteremia for 1-2, 3 and >or=4 d, respectively; p=0.05). Cox regression analysis revealed that bacteremia duration correlated positively with endovascular sources (p=0.006), vancomycin treatment (p=0.016), cardiovascular prosthesis (p=0.025), metastatic infections (p=0.025) and diabetes (p=0.038). It is concluded that persistent bacteremia is a feature of S. aureus infection, irrespective of oxacillin susceptibility, associated with worse outcome. Risk factors include endovascular sources, cardiovascular prosthesis, metastatic infections, vancomycin treatment and diabetes. Patients at risk may benefit from novel treatment strategies.     

Recognition and treatment of neonatal community-associated MRSA pneumonia and bacteremia

Community-associated strains of methicillin-resistant Staphylococcus aureus (CA-MRSA) have recently emerged as a major cause of serious infections among older children and are now being seen in NICU patients. We present the case of a preterm infant with CA-MRSA necrotizing pneumonia and secondary bacteremia.     

Changing patterns of Staphylococcus aureus bacteremia

Medical records of 134 patients with Staphylococcus aureus bacteremia at the Cincinnati General Hospital during 1975-1977 were reviewed. Bacteremia was community-acquired in 48 patients and hospital-acquired in 73 patients. In addition, 13 patients were on chronic hemodialysis. In 22 patients, bacteremia was associated with an infected intravenous catheter; all except one of these patients acquired the infection in the hospital. Thus 21 of 73 (29%) episodes of hospital-acquired S aureus bacteremia were associated with an infected intravenous catheter. Four of the 22 patients with intravenous catheter-associated bacteremia had endocarditis (18%). The overall incidence of endocarditis in this study was 16% (21 of 134 patients). This contrasted with the much higher incidence of endocarditis (64%) in Staphylococcal bacteremia reported from this same hospital in patients during 1940-1954. Possible reasons for this difference are discussed.     

Community-acquired methicillin-resistant Staphylococcus aureus carrying Panton-Valentine leukocidin genes: a lethal cause of pneumonia in an adult immunocompetent patient

Necrotizing pneumonia and fatal septic shock were caused by Panton-Valentine leukocidin-positive, community-acquired, methicillin-resistant Staphylococcus aureus (CA-MRSA) in a previously healthy, 61-y-old female. This patient did not belong to any high-risk group (e.g. homosexuals, military recruits, sports team members, etc.). CA-MRSA infection should be suspected in any adult with severe pneumonia/sepsis.