Wissam El Atrouni

Temporal trends in the incidence of Staphylococcus aureus bacteremia in Olmsted County, Minnesota, 1998 to 2005: a population-based study.

BACKGROUND There is a paucity of population-based studies on Staphylococcus aureus bacteremia (SAB) in the United States. We determined the incidence of and trends in SAB in Olmsted County, Minnesota, over an 8-year period. METHODS A retrospective, population-based, cohort study was done to evaluate the initial episodes of SAB occurring in adult residents of Olmsted County, Minnesota, from 1 January 1998 through 31 December 2005, using the microbiology databases at Mayo Clinic and Olmsted Medical Center in Rochester, Minnesota. RESULTS Of 247 evaluable adult patients with SAB who were included in the incidence calculation, 143 (57.9%) were males, and the median age was 72.1 years (range, 19.5-98.5 years). Episodes of bacteremia were classified according to acquisition type: 58 (23.5%) were nosocomial (N-SAB), 145 (58.7%) were healthcare-associated (HCA-SAB), and 44 (17.8%) were community-acquired (CA-SAB). Methicillin-resistant S. aureus (MRSA) constituted 31.6% of the cases. No community-acquired MRSA bacteremia was noted. The age-adjusted incidence of SAB was 28.3 episodes/100,000 person-years for females and 53.5 episodes/100,000 person-years for males, with an age- and sex-adjusted rate of 38.2 episodes/100,000 person-years. The age- and sex-adjusted incidence of N-SAB, HCA-SAB, and CA-SAB was 9.0, 22.6, and 6.6 episodes/100,000 person-years, respectively. The age- and sex-adjusted incidence of methicillin-susceptible S. aureus was 25.4 episodes/100,000 person-years, and that of MRSA was 12.4 episodes/100,000 person-years. Overall, the incidence rate increased with age but not over the calendar year. The exception was MRSA bacteremia, which increased at a rate of 19.8% (standard error, +/-5.5%) per year during the study. CONCLUSIONS The incidence of SAB in adults remained stable in Olmsted County, Minnesota, from 1998 to 2005, but the proportion of episodes due to MRSA significantly increased over the 8-year period.

Outcome of enterococcal prosthetic joint infection: Is combination systemic therapy superior to monotherapy?

BACKGROUND The optimal medical or surgical therapy and outcome of enterococcal prosthetic joint infection are unknown. METHOD We performed a retrospective cohort study involving all patients with enterococcal total hip or knee arthroplasty infection treated at our institution from 1969 through 1999. The outcome for patients treated with combination systemic antimicrobial therapy (a cell wall-active agent and an aminoglycoside) versus monotherapy with a cell wall-active agent was analyzed. RESULTS Fifty episodes of prosthetic joint infection due to enterococci occurred in 47 patients. The median duration of follow-up was 1253 days (range, 29-4610 days). The median age at the time of diagnosis was 70 years (range, 32-89 years). Fifty percent of episodes (25 of 50 episodes) occurred in male patients; 48% (24 of 50 episodes) involved total hip or knee arthroplasty. The estimate of 2-year survival free of treatment failure was 94% (95% confidence interval [CI], 83%-100%) for patients treated with 2-stage exchange, 76% (95% CI, 58%-100%) for patients treated with resection arthroplasty, and 80% (95% CI, 51.6%-100%) for patients treated with debridement and retention of the components (P=.9). The overall rate of 2-year survival free of treatment failure was 88% (95% CI, 77%-100%) for patients treated with monotherapy and 72% (95% CI, 54%-96%) for patients treated with combination therapy (P=.1). The development of cranial nerve VIII toxicity was significantly more common among patients receiving combination therapy (P=.002). Nephrotoxicity was more frequent in the combination therapy group (occurring in 26% of episodes; P=.09). CONCLUSIONS Enterococcal prosthetic joint infection is uncommon at our institution. Patients receiving combination therapy and those receiving monotherapy did not differ with respect to outcome. There were more cases of ototoxicity in the combination therapy group than there were in the monotherapy group.

Ribosomal RNA Sequence Analysis of Brucella Infection Misidentified as Ochrobactrum anthropi Infection

ABSTRACT A Brucella isolate was identified from purulent material collected during a hip surgery. Two previous blood cultures from the same patient yielded Ochrobactrum anthropi. After rRNA sequencing, all the isolates were identified as Brucella species and subsequently serotyped as Brucella suis. Misidentification of Brucella species remains a problem with bacterial identification systems.

Vancomycin Trough and Acute Kidney Injury: A Large Retrospective, Cohort Study.

Background: The association between vancomycin trough (VT) and acute kidney injury (AKI) at the recommended doses remains controversial. Methods: The authors conducted a retrospective, observational cohort study of 500 adult patients who received vancomycin for ≥72 h. Data collected included 2 main predictors: average VT (including only VTs before the occurrence of AKI), first VT and other possible risk factors for AKI. The baseline characteristics/variables between patients with AKI and patients with no AKI were compared. Logistic regression models were used to develop multivariate models. The authors divided the patients into 4 subgroups: (1) VT <10, (2) 10 ≤ VT < 15, (3) 15 ≤ VT < 20 and (4) VT ≥20 µg/ml. All subgroups were compared to subgroup 2 (reference group). Results: AKI occurred in 12.85% of patients while on vancomycin. The incidence of AKI in subgroups 1-4 was 8.02, 13.61, 13.70 and 31.82%, respectively, using the first VT, that is significantly higher in subgroup 4. Using average VT, AKI incidence was 5, 10.38, 19.01 and 25.58%, respectively, that is significantly higher in subgroups 3 and 4. On multivariate logistic regression, average VT, first VT, average VT >15, first VT >15, methicillin-resistant Staphylococcus aureus infection and morbid obesity were significantly associated with increased incidence of AKI. Conclusion: Clinicians should be careful when aiming for a VT >15 μg/ml as this is associated with increased incidence of AKI.

Relationship between vancomycin tolerance and clinical outcomes in Staphylococcus aureus bacteraemia

Background: Previous data have demonstrated the clinical importance of vancomycin MIC values in Staphylococcus aureus bacteraemia (SAB); however, the impact of vancomycin tolerance (VT) is unknown. Objectives: To compare the frequency of clinical failure between patients with VT and non-VT isolates in SAB. Methods: This was a retrospective cohort study of patients with SAB, excluding treatment <48 h or polymicrobial bacteraemia. The primary outcome was clinical failure (composite of 30 day mortality, non-resolving signs and symptoms, and 60 day recurrence). Vancomycin MIC and MBC were determined by broth microdilution. The association between VT (MBC/MIC ≥32) and clinical failure was evaluated by multivariable Poisson regression. Results: Of the 225 patients, 26.7% had VT isolates. VT was associated with clinical failure (48.0% overall) in unadjusted analysis [68.3% (n = 41/60) versus 40.6% (n = 67/165); P < 0.001] and this relationship persisted in multivariable analysis (adjusted risk ratio, 1.74; 95% CI, 1.36-2.24; P < 0.001). The association between VT and clinical failure was also consistent within strata of methicillin susceptibility [methicillin susceptible (n = 125, risk ratio, 1.67; 95% CI, 1.20-2.32; P = 0.002); methicillin resistant (n = 100, risk ratio, 1.69; 95% CI, 1.14-2.51; P = 0.010)]. Among methicillin-susceptible SAB cases treated with &bgr;-lactam therapy, VT remained associated with clinical failure (risk ratio, 1.77; 95% CI, 1.19-2.61; P = 0.004). Conclusions: VT was associated with clinical failure in SAB, irrespective of methicillin susceptibility or definitive treatment. VT may decrease the effectiveness of cell-wall-active therapy or be a surrogate marker of some other pathogen-specific factor associated with poor outcomes. Future research should evaluate if bactericidal non-cell-wall-active agents improve outcomes in VT SAB.

Bilateral inflammatory myofibroblastic tumor mastoiditis

Inflammatory myoblastic tumors (IMTs) are rare, mesenchymal neoplasms most commonly located in areas of previous inflammation. In the temporal bone, these tumors typically present as solitary, space‐occupying lesions that clinically resemble chronic otitis media.

Isolated Sporothrix schenckii Monoarthritis

Sporothrix schenkii sensu lato is a rare cause of arthritis. Its course is indolent with lack of constitutional symptoms resulting in delayed presentation and diagnosis. It is a dimorphic fungus found ubiquitously in sphagnum moss, decaying vegetation, soil, and hay. Inoculation of dirt into the skin and soft tissues and, in rare instances, inhalation of aerosolized conidia from soil and plants can lead to infection. Subacute and chronic involvement of skin and subcutaneous tissues is the most common manifestation of sporotrichosis in immunocompetent hosts. In patients with underlying risk factors (HIV, alcoholism, diabetes mellitus, organ transplant patients, immunosuppressive medications, steroids, and malignancies), it can often have disseminated visceral, osteoarticular, meningeal, and pulmonary involvement. Sporothrical arthritis most commonly infects knee joint followed by hand and wrist joints. A culture of Sporothrix schenkii sensu lato is the gold standard for the diagnosis of sporotrichosis. Itraconazole is the drug of choice for osteoarticular sporotrichosis. We present a case of sporotrichal arthritis in a patient without skin or lymph node involvement who underwent treatment with itraconazole resulting in resolution of his symptoms.

1580Sexual Health of HIV Infected Patients Attending KUMC ID Clinic

Background. The aim of this study was to identify overall sexually transmitted diseases (STD) burden in HIV infected patients and determine compliance with sexual health screening and treatment based on CDC 2010 Guideline in our HIV clinic. Methods. This is a retrospective cohort study of all adult patients attending at least 2 visits at the University of Kansas Medical Center outpatient infectious diseases clinic between October 1, 2010 and August 15, 2013. Syphilis, gonorrhea, chlamydia, genital warts, genital herpes, hepatitis A, B, C testing frequency, diagnoses and treatments were abstracted from the charts. Period prevalence, compliance with screening methods, frequency, and treatment were measured. Percentages below are calculated out of the total cohort. Results. Of 241 patients included in the analysis, 197 (81.74%) were male, 43 (17.84%) were female, 1 (0.41%) was transgender, 136 (56.43%) were men who have sex with men, and mean age was 42.07 years. During the study period, 3 (1.24%) patients were diagnosed with gonorrhea, 3 (1.24%) had chlamydia, 34 (14.1%) had a positive syphilis test (RPR or EIA), 22 (9.13%) had positive hepatitis B surface antigen, 20 (8.3%) had positive hepatitis C antibodies, 26 (10.8%) had genital warts, 6 (2.5%) had genital herpes, and 4/43 (9.3%) women had positive cervical HPV DNA. At study entry, mean CD4 count was 403 cells/uL, and mean HIV viral load was 282,529 copies/mL. At STD diagnosis, mean CD4 was 352 cells/uL, and mean HIV viral load was 45,132 copies/mL. Testing per guideline occurred in 95.83% of patients for syphilis, 43.75% for chlamydia, 45% for gonorrhea, 90% for hepatitis A, 99.58% for hepatitis B and 96.25% for hepatitis C. Testing frequency per guideline occurred in 81.25% of patients for syphilis, 37.92% for chlamydia, 38.33% for gonorrhea. When STD was diagnosed, treatment was according to guideline for most patients. Conclusion. Compliance with screening methods and frequency was adequate for syphilis and hepatitis, but screening for chlamydia and gonorrhea is suboptimal and can be improved. Disclosures. All authors: No reported disclosures.

396What is the Best Predictor for Vancomycin Nephrotoxicity

396. What is the Best Predictor for Vancomycin Nephrotoxicity? Kassem Hammoud, MD; Neil Goodloe, MD; Wael Haidar, MD; Michael Brimacombe, PhD; Wissam El Atrouni, MD; Internal Medicine/Infectious Diseases, University of Kansas Medical Center, Kansas City, KS; Cox Health System, Springfield, MO, Uruguay; Adena Health Care, Chillicothe, OH; Department of Biostatistics, University of Kansas Medical Center, Kansas City, KS

Reply to “Mistaken Identity of Brucella Infection”

The letter of Yang et al. ([1][1]) is an interesting account of the continuing issues associated with the misidentification of Brucella species by the current commercial identification systems. As mentioned in the letter, we experienced similar issues with the commercial bacterial identification