[Show abstract][Hide abstract] ABSTRACT: The detection of pathogens associated with gastrointestinal disease may be important in certain patient populations, such as immunocompromised hosts, the critically ill, or individuals with prolonged disease that is refractory to treatment. In this study, we evaluated two commercially-available multiplex panels (FilmArray™ Gastrointestinal [GI] Panel [BioFire Diagnostics, Salt Lake City, UT] and the Luminex xTag® gastrointestinal pathogen panel [GPP] [Luminex Corporation, Toronto, Canada]) using Cary-Blair stool samples (n=500) submitted to our laboratory for routine GI testing (e.g., culture, antigen testing, microscopy, individual real-time PCR). At the time of this study, the prototype (non-FDA cleared) FilmArray GI panel targeted 23 pathogens (14 bacterial, 5 viral, 4 parasitic) and testing of 200 μL of Cary-Blair stool was recommended. In contrast, the Luminex GPP assay was FDA-cleared for the detection of 11 pathogens (7 bacterial, 2 viral, 2 parasitic), but had the capacity to identify 4 additional pathogens using a research-use-only protocol. Importantly, the Luminex assay was FDA-cleared for 100 μL raw stool; however, 100 μL Cary-Blair stool was tested by the Luminex assay in this study. Among 230 prospectively collected samples, routine testing was positive for one or more GI pathogens in 19 (8.3%) samples, compared to 76 (33.0%) by the FilmArray and 69 (30.3%) by the Luminex assay. Clostridium difficile (12.6-13.9% prevalence) and norovirus GI/GII (5.7-13.9% prevalence) were two of the most commonly detected pathogens among prospective samples by both assays. Sapovirus was also commonly detected (5.7% positive rate) by the FilmArray assay. Among 270 additional, previously characterized samples, both multiplex panels demonstrated high sensitivity (>90%) for the majority of targets, with the exception of several pathogens, notably Aeromonas sp. (23.8%) by FilmArray and Yersinia enterocolitica (48.1%) by the Luminex assay. Interestingly, the FilmArray and Luminex panels identified mixed infections in 21.1% and 13.0% of positive prospective samples, respectively, compared to only 8.3% by routine methods.
[Show abstract][Hide abstract] ABSTRACT: Cryptosporidium ubiquitum is an emerging zoonotic pathogen. In the past, it was not possible to identify an association between cases of human and animal infection. We conducted a genomic survey of the species, developed a subtyping tool targeting the 60-kDa glycoprotein (gp60) gene, and identified 6 subtype families (XIIa-XIIf) of C. ubiquitum. Host adaptation was apparent at the gp60 locus; subtype XIIa was found in ruminants worldwide, subtype families XIIb-XIId were found in rodents in the United States, and XIIe and XIIf were found in rodents in the Slovak Republic. Humans in the United States were infected with isolates of subtypes XIIb-XIId, whereas those in other areas were infected primarily with subtype XIIa isolates. In addition, subtype families XIIb and XIId were detected in drinking source water in the United States. Contact with C. ubiquitum-infected sheep and drinking water contaminated by infected wildlife could be sources of human infections.
[Show abstract][Hide abstract] ABSTRACT: Background: Community associated Clostridium difficile infection (CA-CDI), i.e., CDI in patients who lack classic CDI risk factors (recent hospitalization or antibiotic use), is increasing and accounts for approximately 50% of CDI cases in central Minnesota. Some have speculated that animals and food may serve as CA-CDI sources. We collected samples from humans, animals, and meat products to explore this hypothesis.
Methods: Since 2007, the Minnesota Department of Health (MDH) has collected and genotyped CD isolates from central Minnesota as part of human CDI surveillance. In November 2011, we began collecting food and companion animal fecal samples (goal n = 600) and retail meat products (goal n = 300) from the same geographic region. Sample characteristics for fecal samples (geographic region, animal diarrhea status, age, antibiotic use) and retail meats (geographic region, antibiotic-free labeling) are recorded. Animal fecal and retail meat samples are cultured using a single alcohol shock method. CD-like colonies are confirmed as CD using egg yolk agar, blood agar, PRO disk, and Gram stain. Confirmed CD isolates undergo binary toxin PCR, toxinotyping, and tcdCgene sequencing.
Results: Sample collection is ongoing. Of 164 animal fecal samples tested to date, 17 (10%) yielded CD; the majority porcine (n = 10) and bovine (n = 4). Preliminary results showed a higher trend in the CD positivity rate among diarrhetic (26%) versus healthy animals (5%), (P = .15). To date, of 129 retail meat samples tested, none were CD-positive. Molecular analysis shows that most CD isolates are binary toxin positive (81%), toxinotype V (75%), with a 39 base pair deletion in tcdC(81%). In parallel, MDH’s human CDI surveillance project has yielded 138 human CD isolates during the same time frame.
Conclusion: CD has been recovered from food animals in Minnesota, but not from retail meats. Future plans include (i) completing collection and CD testing of animal fecal and retail meat samples, (ii) comparative molecular analysis of CD isolates from animals, meats, and humans including pulsed field gel electrophoresis, (iii) and statistical analysis of CD prevalence in relation to sample characteristics. Preliminary data from retail meat currently does not support the hypothesis that meat products are a key source of CA-CDI.
IDWeek 2012 Meeting of the Infectious Diseases Society of America; 10/2012
[Show abstract][Hide abstract] ABSTRACT: A 44-year-old woman with long-standing common variable immunodeficiency who was receiving intravenous immune globulin suddenly had paralysis of all four limbs and the respiratory muscles, resulting in death. Type 2 vaccine-derived poliovirus was isolated from stool. The viral capsid protein VP1 region had diverged from the vaccine strain at 12.3% of nucleotide positions, and the two attenuating substitutions had reverted to the wild-type sequence. Infection probably occurred 11.9 years earlier (95% confidence interval [CI], 10.9 to 13.2), when her child received the oral poliovirus vaccine. No secondary cases were identified among close contacts or 2038 screened health care workers. Patients with common variable immunodeficiency can be chronically infected with poliovirus, and poliomyelitis can develop despite treatment with intravenous immune globulin.
New England Journal of Medicine 06/2011; 364(24):2316-23. DOI:10.1056/NEJMoa1008677 · 55.87 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Neuroinvasive immunodeficiency-associated vaccine-derived polio virus (iVDPV) infection is extremely rare, affecting predominantly persons with B-cell deficiency. Globally, 44 cases have been reported to WHO since 1962. Routine use of oral polio vaccine (OPV) was discontinued in the U.S. in 2000.
Methods: A 44 year-old female with >20 year history of common-variable immunodeficiency (on monthly IVIG) had abrupt onset of left leg cramping followed by weakness in December 2008. Over the next 3 weeks, ascending paralysis developed in all limbs and respiratory muscles. MRI revealed hyperintensity in anterior-horns of C3-C7 and bilateral thalami. She died in March 2009 from complications of hepatic cirrhosis and chronic interstitial pneumonitis with persistent neurologic sequela. A stool culture prior to death grew enterovirus. Viral serotyping and sequencing was performed at MN Dept Health and CDC. An investigation of family and healthcare workers who participated in her care was done.
Results: Poliovirus type 2 antisera neutralized the isolate. Genome sequencing identified 13% nucleotide difference from Sabin type 2 OPV and other sequence properties typical of iVDPV isolates. Attenuating mutations in nucleotide 481 in the 5' noncoding region and amino acid 143 in VP1 had reverted. A household member received 3 OPV doses 13 years prior to patient’s onset. 2038 health care workers were contacted and screened for immunodeficiency, polio vaccination, and neurological symptoms with no secondary cases identified.
Conclusion: The genetic properties of the patient’s isolate were consistent with other highly divergent, neurovirulent iVDPVs. Poliovirus evolves at a known rate of 1% per year suggesting infection occurred about 13 years ago, the time the household member was vaccinated. B-cell immunodeficient patients can be chronic carriers of VDPV despite IVIG and are at risk for polio disease. Clinicians should be familiar with the clinical presentation of polio and contraindications of live-virus vaccines.
Infectious Diseases Society of America 2009 Annual Meeting; 10/2009
[Show abstract][Hide abstract] ABSTRACT: Oral poliovirus vaccine (OPV) has not been used in the United States since 2000. Type 1 vaccine-derived poliovirus (VDPV) was identified in September 2005, from an unvaccinated Amish infant hospitalized in Minnesota with severe combined immunodeficiency. An investigation was conducted to determine the source of the virus and its means of transmission.
The infant was tested serially for poliovirus excretion. Investigations were conducted to detect poliovirus infections or paralytic poliomyelitis in Amish communities in Minnesota, neighboring states, and Ontario, Canada. Genomic sequences of poliovirus isolates were determined for phylogenetic analysis.
No source for the VDPV could be identified. In the index community, 8 (35%) of 23 children tested, including the infant, had evidence of type 1 poliovirus or VDPV infection. Phylogenetic analysis suggested that the VDPV circulated in the community for approximately 2 months before the infant's infection was detected and that the initiating OPV dose had been given before her birth. No paralytic disease was found in the community, and no poliovirus infections were found in other Amish communities investigated.
This is the first demonstrated transmission of VDPV in an undervaccinated community in a developed country. Continued vigilance is needed in all countries to identify poliovirus infections in communities at high risk of poliovirus transmission.
The Journal of Infectious Diseases 02/2009; 199(3):391-7. DOI:10.1086/596052 · 6.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We investigated a cluster of community-associated methicillin-resistant Staphylococcus aureus infections among persons at a wilderness canoe camp. Isolates from the investigation had identical profiles for susceptibility, pulsed-field gel electrophoresis, and toxins. Participants in activities that involve skin injury, person-to-person contact, and inadequate hygiene are at increased risk for methicillin-resistant S. aureus infections.
[Show abstract][Hide abstract] ABSTRACT: Enteric illness outbreaks among middle-/high-school students in consecutive semesters of an educational farm programme were investigated with retrospective cohort studies. During the first outbreak, 31/92 (34%) interviewed students were ill. Risk factors included participating in animal science class (RR 8.1, 95% CI 1.2-55.2) and contact with calves (RR 4.2, 95% CI 1.1-16.2). Stool samples from seven students and two calves yielded Cryptosporidium parvum. Students cared for animals in street clothes and practised poor hand washing. During the second outbreak, 37/81 (46%) interviewed animal science students were ill. Risk factors included having visible manure on hands, and wearing coveralls and boots. Stool samples from seven students and eight calves yielded C. parvum. Student hand washing was still inadequate. Coveralls/boots were cleaned infrequently and removed after hand washing. These outbreaks of cryptosporidiosis resulted from calf contact and inadequate hygiene practices. The failure to adequately implement recommended interventions contributed to the second outbreak.
Epidemiology and Infection 09/2006; 134(4):878-86. DOI:10.1017/S0950268805005649 · 2.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Kingella kingae often colonizes the oropharyngeal and respiratory tracts of children but infrequently causes invasive disease. In mid-October 2003, 2 confirmed and 1 probable case of K kingae osteomyelitis/septic arthritis occurred among children in the same 16- to 24-month-old toddler classroom of a child care center. The objective of this study was to investigate the epidemiology of K kingae colonization and invasive disease among child care attendees.
Staff at the center were interviewed, and a site visit was performed. Oropharyngeal cultures were obtained from the staff and children aged 0 to 5 years to assess the prevalence of Kingella colonization. Bacterial isolates were subtyped by pulsed-field gel electrophoresis (PFGE), and DNA sequencing of the 16S rRNA gene was performed. A telephone survey inquiring about potential risk factors and the general health of each child was also conducted. All children and staff in the affected toddler classroom were given rifampin prophylaxis and recultured 10 to 14 days later. For epidemiologic and microbiologic comparison, oropharyngeal cultures were obtained from a cohort of children at a control child care center with similar demographics and were analyzed using the same laboratory methods. The main outcome measures were prevalence and risk factors for colonization and invasive disease and comparison of bacterial isolates by molecular subtyping and DNA sequencing.
The 2 confirmed case patients required hospitalization, surgical debridement, and intravenous antibiotic therapy. The probable case patient was initially misdiagnosed; MRI 16 days later revealed evidence of ankle osteomyelitis. The site visit revealed no obvious outbreak source. Of 122 children in the center, 115 (94%) were cultured. Fifteen (13%) were colonized with K kingae, with the highest prevalence in the affected toddler classroom (9 [45%] of 20 children; all case patients tested negative but had received antibiotics). Six colonized children were distributed among the older classrooms; 2 were siblings of colonized toddlers. No staff (n = 28) or children aged <16 months were colonized. Isolates from the 2 confirmed case patients and from the colonized children had an indistinguishable PFGE pattern. No risk factors for invasive disease or colonization were identified from the telephone survey. Of the 9 colonized toddlers who took rifampin, 3 (33%) remained positive on reculture; an additional toddler, initially negative, was positive on reculture. The children of the control child care center demonstrated a similar degree and distribution of K kingae colonization; of 118 potential subjects, 45 (38%) underwent oropharyngeal culture, and 7 (16%) were colonized with K kingae. The highest prevalence again occurred in the toddler classrooms. All 7 isolates from the control facility had an indistinguishable PFGE pattern; this pattern differed from the PFGE pattern observed from the outbreak center isolates. 16S rRNA gene sequencing demonstrated that the outbreak K kingae strain exhibited >98% homology to the ATCC-type strain, although several sequence deviations were present. Sequencing of the control center strain demonstrated more homology to the outbreak center strain than to the ATCC-type strain.
This is the first reported outbreak of invasive K kingae disease. The high prevalence in the affected toddler class and the matching PFGE pattern are consistent with child-to-child transmission within the child care center. Rifampin was modestly effective in eliminating carriage. DNA sequence analysis suggests that there may be considerable variability within the species K kingae and that different K kingae strains may demonstrate varying degrees of pathogenicity.
[Show abstract][Hide abstract] ABSTRACT: Rifampin-resistant meningococcal disease occurred in a child who had completed rifampin chemoprophylaxis for exposure to a sibling with meningococcemia. Susceptibility testing of 331 case isolates found only 1 other case of rifampin-resistant disease in Minnesota, USA, during 11 years of statewide surveillance. Point mutations in the RNA polymerase Beta subunit (rpoB) gene were found in isolates from each rifampin-resistant case-patient.
[Show abstract][Hide abstract] ABSTRACT: Athletics-associated methicillin-resistant Staphylococcus aureus (MRSA) infections have become a high-profile national problem with substantial morbidity.
To investigate an MRSA outbreak involving a college football team, we conducted a retrospective cohort study of all 100 players. A case was defined as MRSA cellulitis or skin abscess diagnosed during the period of 6 August (the start of football camp) through 1 October 2003.
We identified 10 case patients (2 of whom were hospitalized). The 6 available wound isolates had indistinguishable pulsed-field gel electrophoresis patterns (MRSA strain USA300) and carried the Panton-Valentine leukocidin toxin gene, as determined by polymerase chain reaction. On univariate analysis, infection was associated (P<.05) with player position (relative risk [RR], 17.5 and 11.7 for cornerbacks and wide receivers, respectively), abrasions from artificial grass (i.e., "turf burns"; RR, 7.2), and body shaving (RR, 6.1). Cornerbacks and wide receivers were a subpopulation with frequent direct person-to-person contact with each other during scrimmage play and drills. Three of 4 players with infection at a covered site (hip or thigh) had shaved the affected area, and these infections were also associated with sharing the whirlpool > or =2 times per week (RR, 12.2; 95% confidence interval, 1.4-109.2). Whirlpool water was disinfected with dilute povidone-iodine only and remained unchanged between uses.
MRSA was likely spread predominantly during practice play, with skin breaks facilitating infection. Measures to minimize skin breaks among athletes should be considered, including prevention of turf burns and education regarding the risks of cosmetic body shaving. MRSA-contaminated pool water may have contributed to infections at covered sites, but small numbers limit the strength of this conclusion. Nevertheless, appropriate whirlpool disinfection methods should be promoted among athletic trainers.
[Show abstract][Hide abstract] ABSTRACT: Background: Rifampin is one of the agents used for chemoprophylaxis for close contacts of cases of invasive meningococcal disease. Rifampin-resistant meningococcal isolates have been reported only rarely. We describe a case of rifampin-resistant invasive meningococcal disease in the sibling of an infant who died from meningococcemia that was attributed to a rifampin-sensitive strain. Methods: Active population-based surveillance for invasive meningococcal disease is carried out statewide in MN and submission of isolates to the state public health laboratory is required. Isolates are serogrouped and further subgrouped using pulsed-field gel electrophoresis (PFGE). Susceptibilities are routinely done using broth microdilution. Sequencing of the rpoB gene was done for the isolates from both siblings. Results: A six-year-old sibling had N. meningitidis isolated from a blood culture collected 3 days after her sister died of meningococcemia and within a day of completing prophylaxis with rifampin. Isolates from both siblings were serogroup C and their PFGE patterns were identical. The first sibling's isolate was sensitive to rifampin (MIC = 0.008 mcg/ml) while the second sibling's isolate was resistant to rifampin (MIC > 1 mcg/ml by broth microdilution and > 32 mcg/ml by Etest). The rpoB gene from both isolates was sequenced and a single point mutation in the resistant strain resulted in an amino acid substitution from serine phenylalanine. This mutation was previously implicated in similar rifampin-resistant sibling strains. Only one other rifampin-resistant isolate had been noted in MN since 1993. Conclusions: Rifampin-resistant secondary cases of meningococcal disease can occur following rifampin prophylaxis. It is important to advise close contacts receiving chemoprophylaxis of the potential for developing meningococcal disease even though they have taken antibiotics. Rifampin resistance in such cases should be considered and alternative prophylaxis discussed. It is useful for public health authorities to monitor susceptibility trends of rifampin and other chemoprophylactic agents to Neisseria meningitidis.
Infectious Diseases Society of America 2003 Annual Meeting; 10/2003