Acinetobacter baumannii is an emerging bacterial pathogen of considerable healthcare concern. Nonetheless, relatively little is known about the organism's virulence factors or their regulatory networks. Septicemia and ventilator-associated pneumonia are two of the more severe forms of A. baumannii disease. To identify virulence factors that may contribute to these disease processes, genetically diverse A. baumannii clinical isolates were evaluated for their ability to proliferate in human serum. A transposon mutant library was created in a strain background that propagated well in serum and screened for members with decreased serum growth. Results revealed that disruption of A. baumannii phospholipase D (PLD) causes a reduction in the organism's ability to thrive in serum, a deficiency in epithelial cell invasion, and diminished pathogenesis in a murine model of pneumonia. Collectively, these results suggest that PLD is an A. baumannii virulence factor.

Correct identification of nonfermenting gram-negative bacilli (NFB) is crucial for patient management. We compared phenotypic identification of 96 clinical NFB isolates with 5' 16S rRNA gene sequencing. Sequencing identified 88 (91.7%) with a > 99% similarity; 61.5% were concordant to phenotypic results indicating the usability of sequencing to identify NFB.

Anamorphic members of the ascomycete family Trichocomaceae including Aspergillus, Penicillium, Paecilomyces, Geosmithia and Sagenomella have been reported from infections in canines. Six clinical isolates (five associated with infections in canines and one from a human source) demonstrated simple phialides producing conidia in long chains and were investigated for their potential relationship to Sagenomella chlamydospora, a known agent of canine disseminated mycosis. Phylogenetic analyses of internal transcribed spacer (ITS) and small subunit (SSU) region sequences revealed that all of the canine-associated isolates were distinct from Sagenomella species. The new anamorphic genus and species Phialosimplex caninus is described to accommodate the clinical isolates. Sagenomella chlamydospora and Sagenomella sclerotialis are transferred to the new genus as Phialosimplex chlamydosporus comb. nov. and Phialosimplex sclerotialis comb. nov.

Francisella tularensis subspecies tularensis consists of two separate populations A1 and A2. This report describes the complete genome sequence of NE061598, an F. tularensis subspecies tularensis A1 isolated in 1998 from a human with clinical disease in Nebraska, United States of America. The genome sequence was compared to Schu S4, an F. tularensis subspecies tularensis A1a strain originally isolated in Ohio in 1941. It was determined that there were 25 nucleotide polymorphisms (22 SNPs and 3 indels) between Schu S4 and NE061598; two of these polymorphisms were in potential virulence loci. Pulsed-field gel electrophoresis analysis demonstrated that NE061598 was an A1a genotype. Other differences included repeat sequences (n = 11 separate loci), four of which were contained in coding sequences, and an inversion and rearrangement probably mediated by insertion sequences and the previously identified direct repeats I, II, and III. Five new variable-number tandem repeats were identified; three of these five were unique in NE061598 compared to Schu S4. Importantly, there was no gene loss or gain identified between NE061598 and Schu S4. Interpretation of these data suggests there is significant sequence conservation and chromosomal synteny within the A1 population. Further studies are needed to determine the biological properties driving the selective pressure that maintains the chromosomal structure of this monomorphic pathogen.

Mycobacterium intracellulare (MIT) was diagnosed postmortem by culture and supporting histopathology in seven birds from a flock of little blue penguins (Eudyptula minor) at the Henry Doorly Zoo (HDZ). These birds represented 20% of the deaths in the population over a 4 yr period. Clinical signs in affected birds included severe respiratory distress characterized by open-mouth breathing with chronic debilitation. On exam, plaques were noted in the larynx, trachea, and soft tissue of the caudal oropharynx. Index cases were identified on necropsy in two birds on loan to another institution in 2003. Following a case confirmed antemortem at the HDZ, a three-drug protocol of rifampin (15 mg/kg p.o. s.i.d.), ethambutol (15 mg/kg p.o. s.i.d.), and clarithromycin (10 mg/kg p.o. s.i.d.) was started on this bird in 2004 and extended to the entire flock in 2005. Gastric wash, fecal samples, and throat plaques were obtained antemortem on five birds within the flock, selected because of the presence of oral plaques, and tested by culture followed by a polymerase chain reaction assay. MIT was detected in gastric washes from four birds and in throat plaques from all five. Three more birds died during treatment. After the seventh bird died, antimicrobial susceptibility testing performed in July 2007 indicated that the MIT was now resistant to most antibiotics tested, including rifampin and ethambutol. The treatment regimen was changed to minocycline (10 mg/kg p.o. b.i.d.) and clarithromycin (10 mg/kg p.o. s.i.d.). Oral plaques were not seen on monthly rechecks of the flock through November 2008. The proposed mechanism of transmission is exposure to wild birds but the source has not been determined. These cases of avian mycobacteriosis caused by MIT are the first known cases reported in little blue penguins.

This report describes a case of Mycobacterium chimaera infection in a patient with a history of chronic obstructive pulmonary disease where the organism was identified by using molecular methods. M. chimaera was identified from fresh lung tissue and from an instrument-negative mycobacterial growth indicator tube broth culture. The utility of using sequence analysis of the internal transcribed spacer region for the rapid identification of a slow-growing nontuberculous Mycobacterium spp. where conventional culture methods were not successful was shown.

This report describes the first case of cerebral aspergillosis in a heart transplantation patient caused by Aspergillus ustus and reviews 15 previously reported cases of invasive aspergillosis in immunocompromised hosts caused by this mold. The utility of molecular analysis for the identification of unusual fungal pathogens is also described. The refractory nature of A. ustus to treatment is similar to other Aspergillus species and treatment options are reviewed.

Background: Differentiating staphylococci in blood cultures is a critical issue, particularly when only one of two cultures is positive by Gram-stain for staphylococci. New tests for identification of Staphylococcus aureus allow faster results and definitive treatment compared to the tube coagulase test interpreted at 24h (TCT24). These newer tests, peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) and real-time polymerase chain reaction (RT-PCR), offer improved sensitivity at higher cost. Data suggest TCT may be interpreted at 4h (TCT4) with little loss of sensitivity. The impact of variability in turnaround time, sensitivity, specificity, and cost on comparative cost-effectiveness is unknown. Our aim was to establish the cost-effectiveness of TCT24, PNA-FISH, RT-PCR, and TCT4 for direct identification of staphylococci in blood cultures. Methods: Decision analysis comparing these strategies was from the institutional perspective. Beside test variables, other variables included patient risk factors, empiric treatment, and follow-up cultures. Probability and cost estimates came from literature and institutional data. Base-case estimates were derived from institutional rates of 73% contamination when CoNS was identified, 67.6% prevalence of risk factors, and 12.4% prevalence of S. aureus when one of two cultures yielded staphylococci. Sensitivity analysis was done across a range of probabilities and costs. Results: In the base-case, TCT4 and TCT24 were more cost-effective than RT-PCR and PNA-FISH ($78 vs.$120 vs.$165 per patient, respectively). The advantage of TCT4 and TCT24 remained robust upon sensitivity analysis. Conclusions: TCT4 should be further evaluated as a rapid, cost-effective means for identification of S. aureus in blood cultures.

Objective.@nbsp; To characterize infection control experience during a 6.5-year period in a cooperative care center for transplant patients. Design.@nbsp; Descriptive analysis. Setting.@nbsp; A cooperative care center for transplanted patients, in which patients and care partners are housed in a homelike environment, and care partners assume responsibility for patient care duties. Patients.@nbsp; Nine hundred ninety one transplant patients. Methods.@nbsp; Infection control definitions from the Centers for Disease Control and Prevention were used to ascertain infection rates. Environmental cultures were used to detect methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), Clostridium difficile, and fungi during the first 18 months. Surveillance cultures were performed for a subset of patients and care partners. Results.@nbsp; From June 1999 through December 2005, there were 19,365 patient-days observed. The most common healthcare-associated infection encountered was intravascular catheter-related bloodstream infection, with infection rates of 5.74 and 4.94 cases per 1,000 patient-days for hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) patients, respectively. C. difficile-associated diarrhea was observed more frequently in HSCT patients than in SOT patients (3.97 vs 0.57 cases per 1000 patient-days;[Formula: see text]). There was no evidence of environmental contamination with MRSA, VRE, or C. difficile. Acquisition of MRSA was not observed. Acquisition of VRE was documented. Conclusion.@nbsp; This study documented that cooperative care was associated with some risk of healthcare-associated infection, most notably intravascular catheter-associated bloodstream infection and C. difficile-associated diarrhea, it appears the incidences of these infections were roughly commensurate with those in other care settings.