Comparative Evaluation of the BD Phoenix Yeast ID Panel and Remel RapID Yeast Plus System for Yeast Identification.

Becton Dickinson Phoenix Yeast ID Panel was compared to the Remel RapID Yeast Plus System using 150 recent clinical yeast isolates and the API 20C AUX system to resolve discrepant results. The concordance rate between the Yeast ID Panel and the RapID Yeast Plus System (without arbitration) was 93.3% with 97.3% (146/150) and 95.3% (143/150) of the isolates correctly identified by the Becton Dickinson Phoenix and the Remel RapID, respectively, with arbitration.

Predictability of urinalysis parameters in the diagnosis of urinary tract infection: a case study.

Early diagnostic strategies to rule out uncomplicated urinary tract infections (UTI) or test of exclusion could significantly improve patient management in addition to providing optimal cost-effectiveness. We evaluated the predictability of dipstick parameters, with particular emphasis on leukocyte esterase (LE) and nitrite (NT) tests and microscopic urine sediment analysis as predictors of urinary tract infection in the setting of an urban university hospital. A total of 9,845 culture positive urine samples (7,095 females, 2,750 males; 8,938 clean catch, 907 catheterized specimens) collected over a period of twelve months from all patients seen at Temple University Hospital, Philadelphia, were included in this retrospective study. Dipstick and urinalysis data were independently correlated and compared with positive culture results. Either individually or in combination, LE and NT were positive in 30% (2,912/9,845), while both LE and NT were negative in 70% (6,933/9,845) of the total culture positive urine samples. There was no correlation of several other measured variables to culture positive urine samples. This study demonstrates that the uses of LE and/or NT are poor screening parameters as predictors of UTI, in the absence of additional clinical information.

Bacteria adhere less to barbed monofilament than braided sutures in a contaminated wound model.

BACKGROUND: Previous studies have found fewer clinical infections in wounds closed with monofilament suture compared with braided suture. Recently, barbed monofilament sutures have shown improved strength and increased timesavings over interrupted braided sutures. However, the adherence of bacteria to barbed monofilament sutures and other commonly used suture materials is unclear. QUESTIONS/PURPOSES: We therefore determined: (1) the adherence of bacteria to five suture types including a barbed monofilament suture; (2) the ability to culture bacteria after gentle washing of each suture type; and (3) the pattern of bacterial adherence. METHODS: We created an experimental contaminated wound model using planktonic methicillin-resistant Staphylococcus aureus (MRSA). Five types of commonly used suture material were used: Vicryl™, Vicryl™ Plus, PDS™, PDS™ Plus, and Quill™. To determine adherence, we determined the number of bacteria removed from the suture by sequential washes. Sutures were plated to determine bacterial growth. Sutures were examined under confocal microscopy to determine adherence patterns. RESULTS: The barbed monofilament suture showed the least bacterial adherence of any suture material tested. Inoculated monofilament and barbed monofilament sutures placed on agar plates had less bacterial growth than braided suture, whereas antibacterial monofilament and braided sutures showed no growth. Confocal microscopy showed more adherence to braided suture than to the barbed monofilament or monofilament sutures. CONCLUSIONS: Barbed monofilament suture showed similar bacterial adherence properties to standard monofilament suture. CLINICAL RELEVANCE: Our findings suggest barbed monofilament suture can be substituted for monofilament suture, at the surgeon's discretion, without fear of increased risk of infection.

Infections in Heart and Lung Transplant Recipients.

Patients undergoing thoracic organ transplantation procedures involving the heart or lung are at increased risk for developing a wide variety of infections due to their underlying immunosuppression and/or other factors. Lung transplant recipients are at high risk for developing infections caused by bacteria, viruses, and opportunistic fungi, whereas heart transplant recipients are at risk for developing infections caused by these same microorganisms, as well as parasitic infections, including toxoplasmosis and New World trypanosomiasis. This review will highlight the various infections that thoracic organ transplant recipients may develop following their procedures.

Innate immune responses to systemic Acinetobacter baumannii infection in mice: neutrophils, but not interleukin-17, mediate host resistance.

Acinetobacter baumannii is a nosocomial pathogen with a high prevalence of multiple-drug-resistant strains, causing pneumonia and sepsis. The current studies further develop a systemic mouse model of this infection and characterize selected innate immune responses to the organism. Five clinical isolates, with various degrees of antibiotic resistance, were assessed for virulence in two mouse strains, and between male and female mice, using intraperitoneal infection. A nearly 1,000-fold difference in virulence was found between bacterial strains, but no significant differences between sexes or mouse strains were observed. It was found that microbes disseminated rapidly from the peritoneal cavity to the lung and spleen, where they replicated. A persistent septic state was observed. The infection progressed rapidly, with mortality between 36 and 48 h. Depletion of neutrophils with antibody to Ly-6G decreased mean time to death and increased mortality. Interleukin-17 (IL-17) promotes the response of neutrophils by inducing production of the chemokine keratinocyte-derived chemoattractant (KC/CXCL1), the mouse homolog of human IL-8. Acinetobacter infection resulted in biphasic increases in both IL-17 and KC/CXCL1. Depletion of neither IL-17 nor KC/CXCL1, using specific antibodies, resulted in a difference in bacterial burdens in organs of infected mice at 10 h postinfection. Comparison of bacterial burdens between IL-17a(-/-) and wild-type mice confirmed that the absence of this cytokine did not sensitize mice to Acinetobacter infection. These studies definitely demonstrate the importance of neutrophils in resistance to systemic Acinetobacter infection. However, neither IL-17 nor KC/CXCL1 alone is required for effective host defense to systemic infection with this organism.

The incidence of and clinical approach to positive allograft cultures in anterior cruciate ligament reconstruction.

OBJECTIVE: To define the incidence of positive allograft cultures in anterior cruciate ligament (ACL) reconstruction and to determine a clinical approach to a positive test. DESIGN: Retrospective chart review, cohort series. SETTING: Urban academic hospital. PATIENTS: All patients who underwent anterior cruciate ligament reconstruction using allograft between January 2003 and December 2008. One hundred fifteen patients met the inclusion criteria. INTERVENTIONS: Culture of allograft before surgical implantation. MAIN OUTCOME MEASURES: Positive allograft culture. RESULTS: Positive allograft cultures were obtained in 3 of 115 grafts (2.6%). Two cultures grew coagulase-negative Staphylococcus and 1 grew Escherichia coli, both from the broth only. CONCLUSIONS: Positive cultures in ACL allografts have a reported incidence of 5.7% to 13.25%. Our current series shows an incidence of 2.6%. No patients who had a culture-positive allograft developed a clinical infection postoperatively. Routine preimplantation culture of soft tissue allografts cannot be recommended given the low incidence of positive culture and lack of correlation with clinical infection. In the presence of a positive preimplantation allograft culture without signs of clinical infection, our series and the 4 other published series in the literature demonstrate that antibiotic treatment is not indicated. In contrast, signs and symptoms of septic arthritis should be aggressively treated with irrigation, debridement, and intravenous antibiotics.

Delayed recognition of a pseudo-outbreak of Mycobacterium terrae.

Pseudo-outbreaks of mycobacteria are difficult to recognize because of long incubation periods for growth and species identification. We report our experience with one clinical microbiology laboratory that isolated a species of nontuberculous mycobacteria from 14 patient specimens. These specimens came from 12 patients at 2 hospitals over a 6-day period and included 6 different fluids or tissues. Because of the delay between mycobacterial specimen submission and growth in culture, the outbreak was not noted until more than a month later. Initial species determination by a reference laboratory indicated that these isolates were Mycobacterium fortuitum. One patient received treatment for presumed M fortuitum brain infection, and it was not effective in changing her clinical course. The isolates were sent to the Centers for Disease Control and Prevention (CDC) for identification and typing by pulsed-field gel electrophoresis. The CDC determined that the isolates were an identical strain of M terrae, thus confirming a pseudo-outbreak. Combining pseudo-outbreak isolates with those correctly identified initially as M terrae during the 6-day period in question, there were 22 samples from 20 patients with M terrae. Since the pseudo-outbreak, the number of cultures of M terrae in the clinical laboratory has returned to baseline levels without any specific intervention.

An outbreak of mediastinitis among heart transplant recipients apparently related to a change in the united network for organ sharing guidelines.

OBJECTIVE: To describe an outbreak of mediastinitis in heart transplant recipients. DESIGN: Retrospective and contemporaneous cohort SETTING: Urban tertiary-care university hospital with a large cardiac transplantation program. PATIENTS: Heart transplant recipients. INTERVENTIONS: Modifications of donor harvest technique; procedures aimed at decreasing skin and mucosal bacterial colonization; strict aseptic technique in the intensive care unit; and aggressive policing of established infection control practices. RESULTS: In April 1999, mediastinitis rates among heart transplant recipients increased abruptly from a baseline of 6 cases per 100 procedures to sequential quarterly rates of 22, 31, and 50 cases per 100 procedures, whereas infection rates in other cardiac operations were unchanged. Bacteria causing these infections were multidrug-resistant "nosocomial" organisms. The epidemic occurred 2 months after a change in the United Network for Organ Sharing organ allocation algorithm. This change resulted in an increase in the duration of preoperative hospitalization from a median of 52 to 79 days (P = .008) and may have promoted prolonged hospitalization of patients with high illness severity. Aggressive multidisciplinary interventions were temporally associated with a return to preoperative mediastinitis rates without changing length of hospitalization prior to transplantation. CONCLUSIONS: Changes in organ allocation for transplant that prolong waiting time in the hospital and alter illness acuity may lead to increased rates of postoperative infection. Measures to limit bacterial colonization may be a helpful countervailing strategy.

Sporadic fatal insomnia with clinical, laboratory, and genetic findings.

A 75-year-old man presented with a three-year history of progressively worsening insomnia and dementia. His mother and older sister had similar disorders. On initial examination, he was awake, apathetic, and disoriented but had no focal neurological deficits. Electroencephalography showed diffuse background slowing with neither periodic discharge nor sleeping activity. A single-photon emission CT scan showed significantly reduced cerebral perfusion in bilateral thalami, basal ganglia, and limbic cortices. In the late stage of his illness, he developed sphincter dysfunction. Laboratory studies showed increased T-lymphocytes and B-lymphocytes and reduced cortisol level. Cerebrospinal fluid 14-3-3 protein was absent. Genetic evaluations failed to show the aspartate to asparagine point mutation at codon 178 but disclosed an asparagine to serine substitution at codon 171 in one allele and a deletion of 24 base pairs in the other allele in the human prion protein gene. These findings led to a diagnosis of sporadic fatal insomnia, which is a recently described prion disease.

Longitudinal epidemiology of multidrug-resistant (MDR) Acinetobacter species in a tertiary care hospital.

BACKGROUND: Acinetobacter species are well-known causes of health care-associated infections. The longitudinal epidemiology of this species in the hospital setting is poorly understood. A sudden, persistent increase in multidrug-resistant (MDR) A baumannii infections occurred beginning in June 2006 at Temple University Hospital in Philadelphia. An analysis was done to describe the longitudinal molecular epidemiology of MDR A baumannii in a tertiary care hospital. METHODS: This was an epidemiologic investigation using repetitive extragenic palindromic-PCR (rep-PCR) of patients with a positive culture for MDR A baumannii admitted to the hospital between February 2006 and January 2010. MDR A baumannii were defined as susceptible only to colistin and/or tigecycline. RESULTS: The incidence rate of MDR A baumannii rose from 0.36 cases per 1,000 patient-days (pre-epidemic) to 0.86 cases per 1,000 patient-days, due mainly to an increase in the surgical intensive care unit. Enhanced infection control measures were implemented, but waves of MDR A baumannii continued to be documented through routine surveillance. Of 32 strains collected in 2006-2007, a single predominant clone and 2 minor clones accounted for almost all of the cases of MDR A baumannii studied. Of 24 strains collected in 2008-2009, another clone, different from those studied in the earlier period, predominated, and was accompanied by 3 minor variants. CONCLUSION: Following an outbreak in the surgical intensive care unit, MDR A baumannii persisted in our institution for a 3-year period despite rigorous infection control measures. An unexpected strain replacement occurred during this period, with the original predominant strain disappearing completely and new minor clones displacing the original minor clones.

Characterization of bacterial biofilms on tracheostomy tubes.

OBJECTIVES/HYPOTHESIS: To characterize the structure and microbial content of biofilms found on tracheostomy tubes. To determine the correlation between the patients' clinical condition and biofilm content. STUDY DESIGN: Prospective observational series. METHODS: Tracheostomy tubes were collected from patients in both the inpatient and outpatient setting at an urban academic medical center. Sections of the tracheostomy tubes were evaluated by confocal microscopy and bacteria from them plated and identified. The number of colony forming units (CFUs) and species present were determined and a univariate analysis performed to correlate them with various clinical factors. RESULTS: Bacteria were cultured from 19 of the 21 tracheostomy tubes collected. There were between 1 x 10(6) and 1 x 10(10) CFUs present in each of the 2 mm sections. Twelve different bacterial species and one fungus were isolated from culture and speciation. The number of bacteria isolated and the CFUs calculated varied in tubes obtained from the same patient at different times. CONCLUSIONS: Biofilms were present on tracheostomy tubes in greater than 90% of tracheostomy tubes collected as early as 7 days after insertion in both the inpatients and outpatients. Although a variety of bacteria were identified in the biofilm, they often appeared as discrete microcolonies that appeared to be monospecies biofilm on confocal microscopy. There was a statistically significant inverse correlation between the number of colony forming units found and frequency of inner cannula change.

Morphine withdrawal lowers host defense to enteric bacteria: spontaneous sepsis and increased sensitivity to oral Salmonella enterica serovar Typhimurium infection.

Understanding the consequences of drug withdrawal on immune function and host defense to infection is important. We, and others, previously demonstrated that morphine withdrawal results in immunosuppression and sensitizes to lipopolysaccharide-induced septic shock. In the present study, the effect of morphine withdrawal on spontaneous sepsis and on oral infection with Salmonella enterica serovar Typhimurium was examined. Mice were chronically exposed to morphine for 96 h by implantation of a slow-release morphine pellet. Abrupt withdrawal was induced by removal of the pellet. In the sepsis model, bacterial colonization was examined and bacterial species were identified by necropsy of various tissues. It was found that at 48 h postwithdrawal, morphine-treated mice had enteric bacteria that were detected in the Peyer's patches (4/5), mesenteric lymph nodes (4/5), spleens (4/10), livers (6/10), and peritoneal cavities (8/10). In placebo pellet-withdrawn mice, only 2/40 cultures were positive. The most frequently detected organisms in tissues of morphine-withdrawn mice were Enterococcus faecium followed by Klebsiella pneumoniae. Both organisms are part of the normal gastrointestinal flora. In the infection model, mice were orally inoculated with S. enterica 24 h post-initiation of abrupt withdrawal from morphine. Withdrawal significantly decreased the mean survival time and significantly increased the Salmonella burden in various tissues of infected mice compared to placebo-withdrawn animals. Elevated levels of the proinflammatory cytokines were observed in spleens of morphine-withdrawn mice, compared to placebo-withdrawn mice. These findings demonstrate that morphine withdrawal sensitizes to oral infection with a bacterial pathogen and predisposes mice to bacterial sepsis.

Potential clindamycin resistance in clindamycin-susceptible, erythromycin-resistant Staphylococcus aureus: report of a clinical failure.

The erm gene product confers clindamycin resistance on Staphylococcus aureus. We report a clindamycin clinical failure where resistance developed on therapy in a D-test-positive strain. D tests of 91 clindamycin-susceptible, erythromycin-resistant S. aureus isolates showed that 68% of methicillin-susceptible and 12.3% of methicillin-resistant S. aureus strains were D-test positive.

Cladophialophora bantiana brain abscess in a solid-organ transplant recipient: case report and review of the literature.

Cerebral phaeohyphomycosis caused by Cladophialophora bantiana is a rare disease. We describe a heart and bilateral lung transplant recipient who was unsuccessfully treated for a C. bantiana brain abscess. This report compares the present case to those of other solid-organ transplant recipients with the same infection and to those of patients who did not receive transplants.