Amanda T. Harrington

Isolation of Bordetella avium and Novel Bordetella Strain from Patients with Respiratory Disease

Bordetella avium is thought to be strictly an avian pathogen. However, 16S rRNA gene sequencing identified 2 isolates from 2 humans with respiratory disease as B. avium and a novel B. avium–like strain. Thus, B. avium and B. avium–like organisms are rare opportunistic human pathogens.

Impact of Strain Typing Methods on Assessment of Relationship between Paired Nares and Wound Isolates of Methicillin-Resistant Staphylococcus aureus

ABSTRACT The anterior nares are the site of choice for the Veterans Administration methicillin-resistant Staphylococcus aureus (MRSA) surveillance program; however, a correlation between nares colonization and concomitant wound infections has not been well established. The purpose of this study was 3-fold: to determine the relatedness of MRSA isolates from 40 paired wound and nares specimens by four different strain typing methods, to determine concordance of typing methods, and to establish a baseline of MRSA types at this medical center. Isolates were typed by repetitive PCR (rep-PCR) (DiversiLab System; DL) and SpectraCell Raman analysis (SCRA) (commercially available methods that can be performed within a clinical lab), pulsed-field gel electrophoresis (PFGE), and an antibiotic susceptibility profile (AB). Whole-genome optical mapping (WGM) (OpGen, Inc.) was performed on selected isolates. All methods agreed that 26 pairs were indistinguishable and four pairs were different. Discrepant results were as follows: 4 where only SCRA was discordant, 3 where only AB was discordant, 2 where both DL and AB were discordant, and 1 where both DL and SCRA were discordant. All WGM agreed with PFGE. After discrepancy resolution, 80% of the pairs were indistinguishable and 20% were different. A total of 56% of nares results were nonpredictive if negative nares and positive wound cultures are included. Methods agreed 85 to 93% of the time; however, congruence of isolates to a clade was lower. Baseline analysis of types showed that 15 pairs were unique to single patients (30 strains, 38%; 47% of the matching pairs). Twenty-five strains (30%) represented a single clade identical by PFGE, SCRA, and DL, decreasing specificity. Typing method and institutional type frequency are important in assessing MRSA strain relatedness.

Significantly larger numbers of methicillin-resistant Staphylococcus aureus bacteria are recovered from polymicrobial respiratory and wound sites by use of chromogenic primary media than by use of conventional culture

ABSTRACT Previous studies have validated the properties and documented the utility of chromogenic agar for surveillance of methicillin-resistant Staphylococcus aureus (MRSA). In this study, we used one of the chromagars, MRSASelect (Bio-Rad), as one of the primary isolation media for selected wound and respiratory clinical specimens which, in our institution, were typically polymicrobial. We examined a total of 638 specimens; 142 (22%) MRSA isolates were recovered. Twenty-six of these isolates were recovered only on the MRSASelect plate, representing a 28% (15/54) increase for endotracheal aspirates/sputa and a 15% increase for superficial wounds/ulcers (11/73) compared to the results with conventional culture. One isolate (1 CFU) was recovered by conventional medium alone. MRSASelect has generally been used for surveillance cultures; however, we document that an additional 21% of MRSA isolates would have gone unreported in these selected clinical specimens using only standard culture media. For 40% (6/15) of inpatients, MRSA isolated from the MRSASelect plate was the sole indicator of MRSA. Although these isolates can represent either colonization or infection, they are a potential reservoir of infection and nosocomial transmission. Our data support the focused use of chromogenic selective media for the increased detection of MRSA in polymicrobial wound and respiratory specimens, which could have an impact on both clinical treatment and infection control.

Multicenter Assessment of Gram Stain Error Rates

ABSTRACT Gram stains remain the cornerstone of diagnostic testing in the microbiology laboratory for the guidance of empirical treatment prior to availability of culture results. Incorrectly interpreted Gram stains may adversely impact patient care, and yet there are no comprehensive studies that have evaluated the reliability of the technique and there are no established standards for performance. In this study, clinical microbiology laboratories at four major tertiary medical care centers evaluated Gram stain error rates across all nonblood specimen types by using standardized criteria. The study focused on several factors that primarily contribute to errors in the process, including poor specimen quality, smear preparation, and interpretation of the smears. The number of specimens during the evaluation period ranged from 976 to 1,864 specimens per site, and there were a total of 6,115 specimens. Gram stain results were discrepant from culture for 5% of all specimens. Fifty-eight percent of discrepant results were specimens with no organisms reported on Gram stain but significant growth on culture, while 42% of discrepant results had reported organisms on Gram stain that were not recovered in culture. Upon review of available slides, 24% (63/263) of discrepant results were due to reader error, which varied significantly based on site (9% to 45%). The Gram stain error rate also varied between sites, ranging from 0.4% to 2.7%. The data demonstrate a significant variability between laboratories in Gram stain performance and affirm the need for ongoing quality assessment by laboratories. Standardized monitoring of Gram stains is an essential quality control tool for laboratories and is necessary for the establishment of a quality benchmark across laboratories.

Multicenter Evaluation of the Accelerate PhenoTest BC Kit for Rapid Identification and Phenotypic Antimicrobial Susceptibility Testing Using Morphokinetic Cellular Analysis

ABSTRACT We describe results from a multicenter study evaluating the Accelerate Pheno system, a first of its kind diagnostic system that rapidly identifies common bloodstream pathogens from positive blood cultures within 90 min and determines bacterial phenotypic antimicrobial susceptibility testing (AST) results within ∼7 h. A combination of fresh clinical and seeded blood cultures were tested, and results from the Accelerate Pheno system were compared to Vitek 2 results for identification (ID) and broth microdilution or disk diffusion for AST. The Accelerate Pheno system accurately identified 14 common bacterial pathogens and two Candida spp. with sensitivities ranging from 94.6 to 100%. Of fresh positive blood cultures, 89% received a monomicrobial call with a positive predictive value of 97.3%. Six common Gram-positive cocci were evaluated for ID. Five were tested against eight antibiotics, two resistance phenotypes (methicillin-resistant Staphylococcus aureus and Staphylococcus spp. [MRSA/MRS]), and inducible clindamycin resistance (MLSb). From the 4,142 AST results, the overall essential agreement (EA) and categorical agreement (CA) were 97.6% and 97.9%, respectively. Overall very major error (VME), major error (ME), and minor error (mE) rates were 1.0%, 0.7%, and 1.3%, respectively. Eight species of Gram-negative rods were evaluated against 15 antibiotics. From the 6,331 AST results, overall EA and CA were 95.4% and 94.3%, respectively. Overall VME, ME, and mE rates were 0.5%, 0.9%, and 4.8%, respectively. The Accelerate Pheno system has the unique ability to identify and provide phenotypic MIC and categorical AST results in a few hours directly from positive blood culture bottles and support accurate antimicrobial adjustment.

Synergistic activity of ceftazidime-avibactam and aztreonam against serine and metallo-β-lactamase-producing gram-negative pathogens

This study assessed the in vitro synergy between ceftazidime, aztreonam, and ceftazidime-avibactam against serine and metallo-β-lactamase (MBL)-producing pathogens via the Etest MIC:MIC ratio and Agar-Etest synergy methods. The combination of aztreonam and ceftazidime-avibactam was synergistic against all Enterobacteriaceae. None of the tested combinations were consistently synergistic against IMP-producing P. aeruginosa.

In Vitro Activity of Retapamulin and Antimicrobial Susceptibility Patterns in a Longitudinal Collection of Methicillin-Resistant Staphylococcus aureus Isolates from a Veterans Affairs Medical Center.

ABSTRACT Mupirocin is a topical antimicrobial used to decolonize patients who carry methicillin-resistant Staphylococcus aureus (MRSA), and the topical agent retapamulin may be a potential alternative therapy. The goal of this study was to determine the in vitro activity of retapamulin as well as a panel of 15 antimicrobial agents, including mupirocin, for 403 MRSA isolates collected longitudinally from a naive population at the Veterans Affairs Puget Sound Health Care System. The MICs for retapamulin had a unimodal distribution, ranging from 0.008 to 0.5 μg/ml. One isolate had an MIC of >16 μg/ml, was also resistant to clindamycin and erythromycin, and was recovered from the nares of a patient undergoing hemodialysis. Twenty-four isolates (6%) and 11 isolates (3%) demonstrated low-level resistance (MICs of 8 to 64 μg/ml) and high-level resistance (MICs of ≥512 μg/ml), respectively, to mupirocin. Isolates were recovered from 10 patients both before and after mupirocin therapy. Of those, isolates from 2 patients demonstrated MIC changes postmupirocin therapy; in both cases, however, strain typing demonstrated that the pre- and postmupirocin strains were different. A total of 386 isolates (96%) had vancomycin MICs of ≤1.0 μg/ml; 340 isolates (84%) were resistant to levofloxacin, 18 isolates (4.5%) were resistant to trimethoprim-sulfamethoxazole, and 135 isolates (33%) had elevated MICs of 4 μg/ml for linezolid. The baseline levels of resistance were low for mupirocin (9%) and even lower for retapamulin (0.25%) Although the use of mupirocin is currently the standard therapy for decolonization practices, the activity of retapamulin warrants its consideration as an alternative therapy in MRSA decolonization regimens.

Does the American Society for Microbiology Meet the Needs of Clinical Microbiologists

There has been increasing concern that the American Society for Microbiology (ASM) is not meeting the needs of the clinical microbiology membership (Division C and related divisions). Some have suggested that clinical microbiologists are underrepresented in the organization, operation, and

Testing of the filter function of a prototype device to eliminate fetal surrogate markers and bacterial load for autotransfusion in postpartum haemorrhage in low-resource settings

26 www.thelancet.com/lancetgh Published Online April 8, 2016 University of Illinois, Chicago, IL, USA (B Collofello BS, N Robinson MD, V Dobiesz MD, P Kutz CCP, A Koch MA, A Harrington PhD, H Esmailbeigi PhD, S Geller PhD) Correspondence to: Brandon Collofello, 1940 W Taylor M/C 584, Center for Global Health, Chicago, IL 60612, USA bcollo2@uic.edu Testing of the fi lter function of a prototype device to eliminate fetal surrogate markers and bacterial load for autotransfusion in postpartum haemorrhage in low-resource settings Brandon Collofello, Nuriya Robinson, Valerie Dobiesz, Pam Kutz, Abby Koch, Amanda Harrington, Hananeh Esmailbeigi, Stacie Geller Abstract Background Postpartum haemorrhage is a leading cause of death in low-income and middle-income countries, but it is also largely preventable. As a potential solution for restoring blood volume in women with life-threatening haemorrhage in low-resource settings, a vaginal blood collection drape with adaptations for autotransfusion has been created. In this study, we aimed to assess the fi ltration function of the autotransfusion system prototype and to determine the degree to which the fi lter removes surrogate markers for amniotic fl uid, fetal cells, and inhibin A, as well as to quantify the reduction of bacterial contaminants in postpartum blood after vaginal delivery.Background Postpartum haemorrhage is a leading cause of death in low-income and middle-income countries, but it is also largely preventable. As a potential solution for restoring blood volume in women with life-threatening haemorrhage in low-resource settings, a vaginal blood collection drape with adaptations for autotransfusion has been created. In this study, we aimed to assess the fi ltration function of the autotransfusion system prototype and to determine the degree to which the fi lter removes surrogate markers for amniotic fl uid, fetal cells, and inhibin A, as well as to quantify the reduction of bacterial contaminants in postpartum blood after vaginal delivery. Methods We collected postpartum blood from four women who had normal spontaneous vaginal delivery of a term pregnancy using an adapted obstetrical blood collection drape. Immediately after the delivery, the research drape was placed under the buttocks of the participant and postpartum blood was collected. The blood entered a sterile system and was fi ltered through a Pall LeukoGuard BC2 Cardioplegia fi lter via a negative pressure pump. We tested prefi ltration and post-fi ltration samples for the presence of fetal cells, inhibin A, and surrogate markers for amniotic fl uid contamination. Cultures of prefi ltered and post-fi ltered blood underwent qualitative analysis, to identify specifi c bacterial species present, and quantitative analysis. Findings We identifi ed Escherichia coli, Bacteroides fragilis, Klebsiella pneumoniae, Enterococcus faecalis, Corynebacterium jeikeium, Lactobacillus spp, and Staphylococcus spp in prefi ltration blood samples. In samples from three of the four participants, bacterial load decreased after fi ltration. However, complete elimination of a bacterial species did not occur in two participants’ post-fi lter cultures. Fetal cells were present in one prefi ltration sample and decreased but remained present after fi ltration. Reduction in α-fetoprotein and inhibin A varied between the four participants’ post-fi ltration samples. Interpretation The fi lter tested in the autotransfusion system prototype did not signifi cantly reduce the surrogate markers tested nor eliminate bacteria in the four samples, although selective removal of Staphylococcus spp might have occurred. The system remains a promising solution to improve health outcomes of women who give birth in low-resource settings but improved fi lter function does need to be addressed. Future studies will test a leucocyte depletion fi lter, previously shown to successfully remove bacterial contaminants, as well as alter device fl ow rates for optimum fi lter function. Funding UIC Chancellor’s Innovation Fund: Spring 2014 Proof-of-Concept Award (V Dobiesz), UIC College of Medicine Craig Fellowship (B Collofello). Copyright

Cutaneous phaeohyphomycosis caused by Biatriospora mackinnonii in a renal transplant recipient

Phaeohyphomycosis is a heterogeneous group of opportunistic infections that are becoming increasingly more prevalent as pathogens in immunocompromised individuals. We present a rare case of cutaneous phaeohyphomycosis caused by Biatriospora mackinnonii in a renal transplant patient. This case also highlights the importance of molecular techniques in the diagnosis of this rare disease.