Current trends in candidemia and species distribution among adults: Candida glabrata surpasses C. albicans in diabetic patients and abdominal sources.

Candidemia rate and species distribution vary according to the type of patients, country of origin and antifungal prophylaxis use. To present current candidemia epidemiological trends. A retrospective examination of candidemia in adults (≥18 years-old) hospitalised from 2007 to 2015. Cases were identified through the microbiology laboratory. Candida species were distinguished based on colony morphology and VITEK-2 YBC cards, (bioMerieux, Durham, NC, USA). Patient characteristics, species distribution, source and outcome were assessed. We encountered 275 patients (294 episodes) with candidemia. The rate of candidemia dropped in 2010 (P = 0.003) without further decline. Nearly all cases (97.5%) were healthcare-associated. C. albicans (n = 118) and C. glabrata (n = 77) proportions varied without a discernable trend. C. glabrata was more common in diabetics [52.9% vs. 32.0% (non-diabetics); P = 0.004] and abdominal sources [53.3% vs. 35.5% (other sources); P = 0.03], especially gastric/duodenal foci [88.9% vs. 44.1% (other abdominal foci); P = 0.02]. All-cause 30-day mortality rate was 43.3% without changes over time or differences between C. albicans and C. glabrata. In conclusion, the candidemia rate remains stable after a decline in 2010. C. albicans remains the most common species but C. glabrata predominates in diabetics and abdominal sources. These findings suggest possible species-related differences in colonisation dynamics or pathogenicity.

Screening for Intermediately Vancomycin-Susceptible and Vancomycin-Heteroresistant Staphylococcus aureus by Use of Vancomycin-Supplemented Brain Heart Infusion Agar Biplates: Defining Growth Interpretation Criteria Based on Gold Standard Confirmation.

BHI agars supplemented with vancomycin 4 (BHI-V4) and 3 (BHI-V3) mg/liter have been proposed for screening vancomycin intermediately susceptible Staphylococcus aureus (VISA) and heteroresistant (hVISA) phenotypes, respectively, but growth interpretation criteria have not been established. We reviewed the growth results (CFU) during population analysis profile-area under the curve (PAP-AUC) of consecutive methicillin-resistant Staphylococcus aureus (MRSA) blood isolates, which were saved intermittently between 1996 and 2012. CFU counts on BHI-V4 and BHI-V3 plates were stratified according to PAP-AUC interpretive criteria: <0.90 (susceptible [S-MRSA]), 0.90 to 1.3 (hVISA), and >1.3 (VISA). CFU cutoffs that best predict VISA and hVISA were determined with the use of receiver operating characteristic (ROC) curves. Mu3, Mu50, and methicillin-susceptible S. aureus (MSSA) controls were included. We also prospectively evaluated manufacturer-made BHI-V3/BHI-V4 biplates for screening of 2010-2012 isolates. The PAP-AUC of 616 clinical samples was consistent with S-MRSA, hVISA, and VISA in 550 (89.3%), 48 (7.8%), and 18 (2.9%) instances, respectively. For VISA screening on BHI-V4, a cutoff of 2 CFU/droplet provided 100% sensitivity and 97.7% specificity. To distinguish VISA from hVISA, a cutoff of 16 CFU provided 83.3% sensitivity and 94.7% specificity; the specificity was lowered to 89.5% with a 12-CFU cutoff. For detecting hVISA/VISA on BHI-V3, a 2-CFU/droplet cutoff provided 98.5% sensitivity and 93.8% specificity. These results suggest that 2-CFU/droplet cutoffs on BHI-V4 and BHI-V3 best approximate VISA and hVISA gold standard confirmation, respectively, with minimal overlap in samples with borderline PAP-AUC. Simultaneous screening for VISA/hVISA on manufacturer-made BHI-V4/BHI-V3 biplates is easy to standardize and may reduce the requirement for PAP-AUC confirmation.

Delayed peripheral venous catheter-related Staphylococcus aureus bacteremia: onset ≥ 24 hours after catheter removal.

Peripheral venous catheter (PVC)-associated bacteremia usually develops during the indwelling period. We present a review of 14 patients who developed delayed onset Staphylococcus aureus bacteremia (D-SAB), 1-6 days after PVC removal, and compare them to 29 patients with early onset PVC-related S. aureus bacteremia (E-SAB). At the time of removal, the catheter site exhibited inflammation in 8 (57.1%) cases. At SAB onset, PVC site inflammation developed in all patients. Compared to E-SAB, patients with D-SAB were more often aged ≥ 65 y (71.4% vs. 34.5%; p = 0.03) and on corticosteroids (35.7% vs. 6.9%; p = 0.02). D-SAB was more complicated with persistent (> 3 days) bacteremia (42.9% vs. 13.8%; p = 0.04), metastatic infections (35.7% vs. 6.9%; p = 0.02), and slightly higher mortality (21.4% vs. 10.3%; p = 0.3). Logistic regression revealed that the predictors of D-SAB were corticosteroids (odds ratio (OR) 2.10, 95% confidence intervals (CI) 1.16-58.61) and age ≥ 65 y (OR 1.63, 95% CI 1.12-23.30). These patients may have impaired local/systemic defenses that lead to D-SAB, or a blunted host response with delayed recognition.

Lack of association of outcomes with treatment duration and microbiologic susceptibility data in Clostridium difficile infections in a non-NAP1/BI/027 setting.

BACKGROUND: Concerns regarding the poor response of severe Clostridium difficile infection (CDI) treated with metronidazole have arisen over the last 5 y. METHODS: We conducted a prospective, non-interventional study of CDI cases at our institution to evaluate the role of drug resistance, co-morbidities, and the emergence of hypervirulent strains on patient outcomes. A total of 118 adult inpatients with diarrhea and a positive stool for C. difficile toxin immunoassay had positive stool cultures and were included in the study. All 118 isolates had vancomycin and metronidazole susceptibility testing via the E-test method; rep-PCR was performed on 47 isolates. Of the 118 study patients, 107 were treated with either metronidazole or vancomycin. RESULTS: Initial therapy was metronidazole in 98.1% (n = 105) and vancomycin in 1.9% (n = 2) patients. Evaluable clinical response within 5 days of treatment was noted in 52.5% (52/99) of cases. The mean duration of treatment was 11.7 ± 7.2 days. The 30-day all-cause mortality rate was 24.6% (29/118). Recurrence occurred in 23.6% (21/89). A recent stay in the intensive care unit was associated with increased 30-day mortality (odds ratio 3.58, p = 0.012). There were no isolates resistant to metronidazole or vancomycin. Only 1 isolate was possibly related to the NAP1/BI/027 reference strain. No strain-related differences in deaths or recurrence were noted. CONCLUSIONS: Deaths related to CDI in our study appear to be related to multiple factors and did not appear to be independently related to antibiotic susceptibility, strain type, or treatment duration.

Long-term outcomes of cardiovascular implantable electronic devices in patients with Staphylococcus aureus bacteremia.

BACKGROUND: The use of cardiovascular implantable electronic devices (CIEDs) is increasing. Staphylococcus aureus bacteremia (SAB) poses a risk for hematogenous seeding of the device. Our aim is to identify risk factors associated with secondary CIED infection, due to hematogenous seeding, during SAB from an unrelated primary focus. METHODS: All patients with SAB and CIED were screened. Patients with SAB due to a primary source unrelated to the CIED were included. Patients were classified into cases if CIED infection was documented and controls without CIED infection during a minimum of 12 weeks follow-up. A retrospective review of patients' charts was done. RESULTS: Thirty patients with CIED and SAB from an unrelated focus were identified. CIED infection developed in 11 patients (36.7%). No significant differences were noted between cases and controls in the source, time-to-therapy, and time-to-intervene but infected devices were more likely to be implantable cardioverter-defibrillators (ICD) versus permanent pacemakers (PPMs) (9/11 [81.8%] vs 2/11 [18.2%] respectively, crude odds ratio 12.6, 95% confidence interval 10.8-14.4; P = 0.003). CONCLUSION: Hematogenous seeding of a CIED during SAB from an unrelated focus is not uncommon. The risk factors for CIED seeding are unknown but ICD devices seem to be at greater risk when compared to PPM. The reasons are not yet clear. Larger studies are needed to better define risk factors and design preventive measures.

Relevance of vancomycin-intermediate susceptibility and heteroresistance in methicillin-resistant Staphylococcus aureus bacteraemia.

OBJECTIVES: To assess the relevance of vancomycin-intermediate susceptibility (VISA) and heteroresistance (hVISA) in methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia. METHODS: We determined vancomycin MICs for 371 saved MRSA blood isolates (2002-03; 2005-06) by Etest and broth microdilution (BMD), screened for hVISA (Etest methods), determined the population analysis profile (PAP)/AUC for isolates with suspected reduced susceptibility (MICs >2 mg/L and/or hVISA-screen-positive versus Mu3 (hVISA control), and stratified patient characteristics and outcome according to susceptibility phenotype: VISA (PAP/AUC >1.3), hVISA (PAP/AUC 0.9-1.3), and susceptible (S-MRSA; PAP/AUC <0.9). RESULTS: PAP/AUC revealed 6 (1.6%) VISA and 30 (8.1%) hVISA phenotypes. The Etest MIC was above the susceptibility cut-off (2 mg/L) for all VISA isolates, whereas the BMD MIC was within the susceptibility range in two (33.3%) instances. Eight hVISA isolates (26.7%) with MICs of 2 mg/L were hVISA-screen negative. SCCmec typing revealed SCCmec II in 100% of VISA, 86.7% of hVISA and 75.5% of S-MRSA isolates (P = 0.04). Prior vancomycin use was documented in 100% of VISA, 73.3% of hVISA and 52.2% of S-MRSA cases (P = 0.002). Outcome (compared in 243 vancomycin-treated patients with MICs of 2 mg/L) revealed longer time to clearance in VISA cases [12.1 ±â€Š13.1 days versus 3.3 ±â€Š3.9 (hVISA) and 3.7 ±â€Š5.1 (S-MRSA); P = 0.001], more frequent endocarditis [33.3% versus 9.1% (hVISA; P = 0.1) and 4.2% (S-MRSA; P = 0.001)] and attributable mortality [33.3% versus 9.1% (hVISA; P = 0.1) and 8.4% (S-MRSA); P = 0.08]. CONCLUSIONS: No adverse outcome was documented with hVISA phenotype, whereas VISA contributed to vancomycin treatment failure. VISA and hVISA appear to emerge in SCCmec II isolates among vancomycin-exposed patients and are better detected by Etest.

Differences in patient risk factors and source of candidaemia caused by Candida albicans and Candida glabrata.

There is an increasing frequency of candidaemia caused by Candida glabrata which has decreased in vitro susceptibility to fluconazole. Differences in risk factors for candidaemia caused by C. glabrata and C. albicans have not been formally evaluated in a diverse patient group. We performed a retrospective study of adult inpatients from January 1, 2003 to April 30, 2008 with C. glabrata and C. albicans candidaemia at a single tertiary care centre in Detroit, Michigan to evaluate for differences in risk factors and presumed source of infection in these groups. Patients' underlying conditions, risk factors and source of infection (probable or definite) were compared. Among 119 patients, 80 (67.2%) were C. albicans and 39 (32.8%) C. glabrata. Using logistic regression analysis, patients with C. glabrata infection were more likely to have diabetes mellitus (OR 2.43; 95% CI, 1.06-5.54) and abdominal source of infection (OR 4.53, 95% CI, 1.72-11.92). Mortality rates in the two groups were similar. Patients with C. glabrata candidaemia are more likely to be diabetic and have an abdominal source of infection compared with patients with C. albicans.

Are Blacks at Higher Risk for Vancomycin-Related Acute Kidney Injury?

BACKGROUND: Black individuals have a higher lifetime risk of acute kidney injury (AKI) and chronic kidney disease than whites. Vancomycin has a potential for nephrotoxicity. The objective of this study was to determine whether the incidence of AKI among patients being treated with vancomycin differs by race. METHODS: Retrospective study of adult (3 ≥18 years) inpatients who were on vancomycin for 348 hours between January 2012 and December 2014. Data on demographics, comorbid conditions, clinical characteristics, vancomycin dose, duration, and nephrotoxic drugs were collected. Patients with a creatinine clearance <30 mL/min or undergoing dialysis were excluded. RESULTS: We identified 1130 patients during the study period; 48.1% (544) were black. The overall incidence of AKI was 8.2% (10.1% blacks, 6.5% whites; P = .03). Independent predictors of AKI included black race (P = .011); higher Charlson score (P = .006); higher body mass index (BMI; P = .002); higher vancomycin trough level (P < .0001); and sepsis/systemic inflammatory response syndrome (<.0001), pneumonia (P = .001) or gastrointestinal/genitourinary (P = .025) as the source of infection. CONCLUSION: The incidence of vancomycin-related AKI was higher in blacks, independent of other risk factors. Based on our study, vancomycin trough levels and renal function need to be closely monitored in blacks.

Role of SCCmec type in outcome of Staphylococcus aureus bacteremia in a single medical center.

Staphylococcus aureus virulence factors may determine infection presentation. Whether SCCmec type-associated factors play a role in S. aureus bacteremia is unclear. We conducted a prospective observation of adult inpatients with S. aureus bacteremia (1 November 2005 to 31 December 2006), performed SCCmec typing of methicillin-resistant S. aureus (MRSA) isolates, and stratified the results according to SCCmec type. We studied 253 patients. MRSA accounted for 163 (64.4%) cases. The illness severity index was similar in MRSA and methicillin-sensitive S. aureus (MSSA) cases. MRSA caused higher in-hospital mortality (23.9% versus 8.9%; P=0.003), longer bacteremia (4.7+/-6.5 days versus 2.7+/-2.9 days; P=0.01), but similar metastatic infection (14.7% versus 15.6%). Stratifying the results according to SCCmec type revealed significant differences. SCCmec type II caused highest mortality (33.3%) versus type IVa (13.5%), other MRSA (12.5%), and MSSA (8.9%). SCCmec IVa produced the highest metastatic infection (26.9% versus 9.1% [SCCmec II], 8.3% [other MRSA], and 15.6% [MSSA]). Persistent bacteremia (>or= 7 days) was similar in all SCCmec types (16.7 to 20.7%); each exceeded MSSA (6.7%; P=0.05). In multivariate analysis, SCCmec II was a predictor of mortality (odds ratio [OR]=3.73; 95% confidence interval [CI] = 1.81 to 7.66; P=0.009), SCCmec IVa was a predictor of metastatic infection (OR=3.52; CI=1.50 to 8.23; P=0.004), and MRSA (independent of SCCmec type) was a predictor of persistent bacteremia (OR=4.16; CI=1.47 to 11.73; P=0.007). These findings suggest that SCCmec-associated virulence factors play a role in the outcome of S. aureus bacteremia. Additional studies are needed to identify which virulence factors are the determinants of increased mortality with SCCmec type II and metastatic infection with SCCmec type IVa.

Vancomycin MIC plus heteroresistance and outcome of methicillin-resistant Staphylococcus aureus bacteremia: trends over 11 years.

Vancomycin MICs (V-MIC) and the frequency of heteroresistant vancomycin-intermediate Staphylococcus aureus (hVISA) isolates are increasing among methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) isolates, but their relevance remains uncertain. We compared the V-MIC (Etest) and the frequency of hVISA (Etest macromethod) for all MRSA blood isolates saved over an 11-year span and correlated the results with the clinical outcome. We tested 489 isolates: 61, 55, 187, and 186 isolates recovered in 1996-1997, 2000, 2002-2003, and 2005-2006, respectively. The V-MICs were < or = 1, 1.5, 2, and 3 microg/ml for 74 (15.1%), 355 (72.6%), 50 (10.2%), and 10 (2.1%) isolates, respectively. We detected hVISA in 0/74, 48/355 (13.5%), 15/50 (30.0%), and 8/10 (80.0%) isolates with V-MICs of < or = 1, 1.5, 2, and 3 microg/ml, respectively (P < 0.001). The V-MIC distribution and the hVISA frequency were stable over the 11-year period. Most patients (89.0%) received vancomycin. The mortality rate (evaluated with 285 patients for whose isolates the trough V-MIC was > or = 10 microg/ml) was comparable for patients whose isolates had V-MICs of < or = 1 and 1.5 microg/ml (19.4% and 27.0%, respectively; P = 0.2) but higher for patients whose isolates had V-MICs of > or = 2 microg/ml (47.6%; P = 0.03). However, the impact of V-MIC and hVISA status on mortality or persistent (> or = 7 days) bacteremia was not substantiated by multivariate analysis. Staphylococcal chromosome cassette mec (SCCmec) typing of 261 isolates (including all hVISA isolates) revealed that 93.0% of the hVISA isolates were SCCmec type II. These findings demonstrate that the V-MIC distribution and hVISA frequencies were stable over an 11-year span. A V-MIC of > or = 2 microg/ml was associated with a higher rate of mortality by univariate analysis, but the relevance of the V-MIC and the presence of hVISA remain uncertain. A multicenter prospective randomized study by the use of standardized methods is needed to evaluate the relevance of hVISA and determine the optimal treatment of patients whose isolates have V-MICs of > or = 2.0 microg/ml.

Association of parvovirus B19 infection with glomerulonephritis in an immunocompetent host: a case report.

We present the case of an immunocompetent host with acute glomerulonephritis following parvovirus B19 infection. Renal biopsy demonstrated immune-mediated disease; parvovirus B19 DNA was detected in renal tissue and blood. The patient improved with corticosteroid therapy. Repeat serology 3 months later confirmed recovery from the acute viral infection, although viraemia persisted.

Fusobacterium nucleatum: A cause of subacute liver abscesses with extensive fibrosis crossing the diaphragm, mimicking actinomycosis.

INTRODUCTION: Fusobacterium nucleatum is a Gram-negative, obligate anaerobic bacterium which predominantly resides within the oral cavity and causes acute abscesses and venous thrombosis, primarily in the head and neck region, but could have unique clinical presentations in different anatomical regions of the body. CASE REPORT: We present a case of subacute liver abscesses extending to the lung. The histopathological examination showed extensive necrosis and fibrosis. The chronic course, extensive fibrosis and extension across the anatomic barriers were suggestive of actinomycosis. two sets of blood cultures grew Fusobacterium nucleatum, only 16s rRNA analysis of the liver tissue and pleural fluid revealed F. nucleatum DNA without other organisms. The clinical and pathological features of our case illustrate that F. nucleatum may mimic actinomycosis. CONCLUSIONS: This case illustrates that F. nucleatum should be considered in patients with subacute infections with extensive fibrosis that crosses anatomic barriers, mimicking actinomycosis.

Classification of bloodstream infections in patients recently discharged from acute-care facilities: Hospital acquired or healthcare-associated community onset?

Laboratory-identified bloodstream infections (LAB-ID BSIs) in recently discharged patients are likely to be classified as healthcare-associated community-onset (HCA-CO) infections, even though they may represent hospital-onset (HO) infections. A review of LAB-ID BSIs among patients discharged within 14 days revealed that 109 of 756 cases (14.4%) were HO infections. The BSI risk being misclassified as HCA CO may underestimate the hospital infection risk.

Low Frequency of Staphylococcus Aureus in Lower Extremity Skin and Soft Tissue Infections.

BACKGROUND: Staphylococcus aureus is often implicated in skin/soft tissue infections (SSTI). However, SSTI at sites of pressure necrosis and peripheral vascular disease (PVD) are often polymicrobial. The frequency of S aureus in these infections is uncertain. METHODS: We retrospectively reviewed culture results from adults (January 1, 2015-March 31, 2017), evaluated their records and selected SSTI in lower extremities. The patient demographics, comorbidities, characteristics and culture results were recorded. The results were stratified by S aureus status and a composite risk score (RS) was developed (2 points for each difference in S aureus frequency with P < 0.05 [chi-square test] and 1 point for P = 0.06-0.1). The predictors of S aureus were determined by regression analysis using SSPS software. RESULTS: We encountered 356 lower extremity-SSTI (243 foot/ankle, 56 tibia/calf, 30 thigh, 12 hip and 15 groin). S aureus was detected in 173 (48.6%) cases, 59.6% were methicillin-resistant isolates. S aureus was more common in lesions without necrosis (56.3% vs. 42.9%; P = 0.01), with drainage (59.6% vs. 44.7%; P = 0.02), in male sex (53.2% vs. 40.0%; P = 0.02) and was less common in patients with PVD (38.1% vs. 50.9%; P = 0.07), and paraplegia (39.6% vs. 50.0%; P = 0.2). S aureus was less common in polymicrobial SSTI (45.0% vs. 58.5%; P = 0.03). RS of 0-8 correlated with increasing S aureus prevalence from 23.1% (RS = 0-1) to 78.6% (RS = 8; P<0.001). The predictors of S aureus were drainage (odds ratio [OR] = 1.83; 95% confidence intervals [CI]: 1.11, 3.02), lack of PVD (OR = 1.59; CI: 1.03, 2.46) and absence of necrosis (OR = 1.91; CI: 1.08, 3.40). CONCLUSIONS: Patients with suspected polymicrobial lower extremity-SSTI and low RS may not need empirical antistaphylococcal therapy.

Misdiagnosis of community-acquired pneumonia and inappropriate utilization of antibiotics: side effects of the 4-h antibiotic administration rule.

BACKGROUND: The 2003 Infectious Diseases Society of America guidelines for community-acquired pneumonia (CAP) recommend the initiation of antibiotic therapy within 4 h of hospitalization. This quality indicator has been linked to the incentive compensation of third-party payers to hospitals. We evaluated the impact of this recommendation on the diagnosis of CAP and the utilization of antibiotics. METHODS: All patients with a hospital admission diagnosis of CAP before publication of the guidelines (January to June 2003) and after publication of the guidelines (January-June 2005) were included. We collected data on clinical signs and symptoms on presentation, chest radiograph findings, blood cultures prior to therapy with antibiotics, time to antibiotic administration, pneumonia severity index (PSI) score, confusion, urea, respiratory rate, BP, and age >or= 65 years (CURB-65), and mortality. RESULTS: A total of 518 patients were included in the study. More patients in 2005 had a hospital admission diagnosis of CAP without radiographic abnormalities compared to 2003 (2005, 91 patients [28.5%]; 2003, 41 patients [20.6%]; p = 0.04), and more patients received antibiotics within 4 h of triage (2005, 210 patients [65.8%]; 2003, 107 patients [53.8%]; p = 0.007). Blood cultures prior to antibiotic administration increased (2005, 220 patients [69.6%]; 2003, 93 patients [46.7%]; p < 0.001). However, the final diagnosis of CAP dropped to 58.9% in 2005 from 75.9% in 2003 (p < 0.001). The mean (+/- SD) antibiotic utilization per patient increased to 1.66 +/- 0.54 in 2005 compared to 1.39 +/- 0.58 in 2003 (p < 0.001). There were no significant differences in PSI or CURB-65 scores, or mortality. CONCLUSIONS: Linking antibiotic administration within 4 h of hospital admission (as a quality indicator) to financial compensation may result in an inaccurate diagnosis of CAP, inappropriate utilization of antibiotics, and thus less than optimal care.

Increase in the rate of sternal surgical site infection after coronary artery bypass graft: a marker of higher severity of illness.

OBJECTIVE: To evaluate factors related to a gradual rise in sternal surgical site infection (SSI) rates. DESIGN: Retrospective cohort study. SETTING: A 608-bed, tertiary care teaching hospital. PATIENTS: All patients who underwent coronary artery bypass graft (CABG) from January 2000 through September 2004. RESULTS: Of 3,578 patients who underwent CABG, 144 (4%) had sternal SSI. There was an increase in infection rate, with a marked reduction in the number of operations per year. The percentage of patients with peripheral vascular disease increased from 12% to 24.3% (P<.001), and the percentage with congestive heart failure increased from 17% to 22% (P<.001). Between 2002 and 2004, the mean duration of surgery increased from 233 to 290 minutes (P<.001), the percentage of patients with a National Nosocomial Infections Surveillance System (NNIS) risk index of 2 increased from 14.3% to 38% (P<.001), and the percentage of patients with a postoperative stay in the intensive care unit of greater than 72 hours increased from 29% to 40.6% (P<.001). Multivariate analysis showed diabetes mellitus, peripheral vascular disease, obesity, duration of surgery, and postoperative stay in the intensive care unit of greater than 72 hours to be independently associated with infection. CONCLUSIONS: An increase in infection in the CABG population not associated with an outbreak may be a reflection of a change in the severity of illness. Preoperative, intraoperative, and postoperative markers for increased infection risk may be used, in addition to the NNIS risk index, to assess the patient population risk.

Prevalence of nasal colonization among patients with community-associated methicillin-resistant Staphylococcus aureus infection and their household contacts.

OBJECTIVE: To evaluate the prevalence of colonization among patients with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection and their household contacts. DESIGN: Prospective, observational laboratory study of nasal colonization among patients and their household members from September 15, 2004, to February 20, 2006. SETTING: A 600-bed, urban, academic medical center. PATIENTS: Fifty-one patients who presented with CA-MRSA infections and 49 household members had cultures of nasal swab specimens performed. RESULTS: Skin and soft-tissue infections were seen in 50 patients (98%) and 2 household members. Twenty-one (41%) of 51 patients and 10 (20%) of 49 household members were colonized with MRSA. An additional 5 patients (10%) and 12 household members (24%) were colonized with methicillin-susceptible Staphylococcus aureus. Most MRSA isolates (95%; infective and colonizing) carried the staphylococcal cassette chromosome mec type IV complex, and 67% represented a single clone, identical to USA 300. Of the colonized household members, 5 had isolates related to the patients' infective isolate. CONCLUSIONS: The frequency of CA-MRSA colonization among household members of patients with CA-MRSA infections is higher than rates reported among the general population. Among colonized household members, only half of the MRSA strains were related to the patients' infective isolate. Within the same household, multiple strains of CA-MRSA may be present.

Polymicrobial Staphylococcus aureus bacteremia: Frequency, distinguishing characteristics and outcome.

Staphylococcus aureus bacteremia (SAB) is usually monomicrobial (M-SAB). We reviewed SAB in adults (≥18years old) over a 13year-period and compared polymicrobial (P-SAB) and M-SAB. We encountered 93 P-SAB among 1537 SAB cases (6.1%). The source distribution was comparable; however, source-specified differences were apparent. P-SAB was noted in 12/58 (20.7%) necrotizing soft tissue infections/sacral decubiti and foot gangrene vs. 1/122 (0.8%) cellulitis/abscesses (P<0.001), in 7/64 (10.9%) femoral intravascular catheters (IVC) vs.16/376 (4.3%) IVC in other sites (P=0.03) and 15/134 (11.2%) healthcare-associated pneumonia (HAP) vs. 1/33 (3.0%) community-associated cases (P=0.1). Methicillin-resistance frequency was similar but community-associated SCCmec types (IV/V) were infrequent (17.9% vs. 34.2%; P=0.04). P-SAB was associated with higher mortality (50.5% vs. 24.2%; P<0.001) across nearly all sources. In summary, P-SAB is infrequent, usually encountered in necrotizing soft tissue infections/decubiti, femoral IVC and possibly HAP. The actual incidence of S. aureus in these infections should be defined.

Time to positivity in Staphylococcus aureus bacteremia: possible correlation with the source and outcome of infection.

BACKGROUND: Staphylococcus aureus bacteremia often persists and causes metastatic infections. It is unknown whether the time between blood culture incubation and growth detection (i.e., the time to positivity) in a continuously monitored system--a probable surrogate marker of bacteremia severity--correlates with outcome. METHODS: We performed a prospective, observational study involving adult inpatients who had S. aureus bacteremia between 1 January 2002 and 30 June 2003 at a 600-bed teaching hospital. Measurements included time to positivity in initial blood culture series, duration of bacteremia, rate of metastatic infection, and outcome. RESULTS: A total of 376 S. aureus bacteremias (> or = 1 positive blood culture result) were reported for 357 patients aged 18-103 years (median age, 59 years); 64 bacteremias were excluded because blood was drawn after antibiotic therapy was started (n = 59) or through an intravascular catheter (n = 5). The source of infection was identified in 244 series (78.2%). Metastatic infection was detected in 25 bacteremias (8.0%). The mortality rate was 25.6%. The duration of bacteremia (determined in 251 series) was 1-59 days (median duration, 1 day; 70th percentile, 3 days). The time to positivity ranged from 4.2 to 98.2 h (median time to positivity, 15.5 h) and was significantly shorter for patients with an endovascular source of infection (14.9+/-5.4 vs. 19.5+/-10.6 h; P < .0005), extended duration (i.e., > or = 3 days) of bacteremia (14.1+/-4.2 vs. 18.6+/-9.2 h; P < .0005), and metastatic infection (12.9+/-5.9 vs 18.0+/-9.3 h; P = .007). Analysis of a range of cutoff values demonstrated that a time to positivity of < or = 14 h yielded the best sensitivity and specificity for predicting the source and outcome of infection. Logistic regression analyses revealed that a time to positivity of < or = 14 h was an independent predictor of an endovascular source of infection (P < .0005), extended bacteremia (P < .0005), metastatic infection (P < .0005), and attributable mortality (P = .017). CONCLUSIONS: Time to positivity in S. aureus bacteremia may provide useful diagnostic and prognostic information. Growth of S. aureus within 14 h after the initiation of incubation may identify patients with a high likelihood of endovascular infection sources, delayed clearance, and complications.

Facklamia Species and Streptococcus pneumoniae Meningitis: A Case Report and Review of the Literature.

Facklamia sp are Gram-positive cocci that are often mistaken for viridans streptococci, but they rarely cause invasive disease. In this report, we describe a case of mixed Facklamia sp and Streptococcus pneumoniae meningitis in an immunocompetent host with sinusitis. This case demonstrates that Facklamia sp may be part of normal human flora but can be associated with invasive disease.