Elizabeth Cebelinski

Outbreak of Osteomyelitis/Septic Arthritis Caused by Kingella kingae Among Child Care Center Attendees

Objective.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. Methods.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. Results.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. Conclusions.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.

Subtyping Cryptosporidium ubiquitum, a Zoonotic Pathogen Emerging in Humans

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.

Recurrent outbreaks of cryptosporidiosis associated with calves among students at an educational farm programme, Minnesota, 2003

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.

Sapovirus Outbreaks in Long-Term Care Facilities, Oregon and Minnesota, USA, 2002–2009

Sapovirus gives new meaning to the phrase “cradle to grave.” Historically, sapovirus has been associated with gastrointestinal illness in children living in group settings such as hospitals, shelters, or refugee camps. But now, sapovirus outbreaks are occurring among elderly residents of long-term care and similar facilities. These elderly residents are especially vulnerable to rapidly transmitted gastrointestinal viruses and serious complications. This virus has been making the rounds in long-term care facilities since 2002, and outbreaks started increasing in 2007. Sapovirus testing should be added to routine diagnostic workups for gastrointestinal infections, regardless of patient age group. Results can be used to develop prevention, control, and treatment guidelines, especially for vulnerable elderly populations.

An Outbreak of Foodborne Illness Among Attendees of a Wedding Reception in Wisconsin Likely Caused by Arcobacter butzleri

BACKGROUND Arcobacter species, primarily Arcobacter butzleri, are widely distributed among animals, infrequently isolated from humans, and previously not associated with outbreaks of foodborne illness. We report results of an investigation of a foodborne outbreak that occurred among attendees of a wedding reception in Wisconsin, United States, and was likely caused by A. butzleri. METHODS We conducted a case-control study among reception attendees and a laboratory investigation to determine the extent, source, and cause of the outbreak. A clinical case was defined as diarrhea in an attendee with illness onset ≤7 days following the wedding reception. RESULTS The case-control study included 47 of 51 case patients and 43 non-ill attendees. Results demonstrated that consuming broasted chicken was the only factor significantly associated with illness (odds ratio 10.51; 95% confidence interval 1.28, 476.4). Five patients provided stool specimens. Comprehensive culture and polymerase chain reaction (PCR) testing did not detect common bacterial or viral pathogens. Subsequent testing with PCRs targeting 16S/23S rDNA of the three most clinically relevant Arcobacter spp. and the rpoB/C gene of A. butzleri provided products confirmed as A. butzleri (four patients) and A. cryaerophilus (one patient) by sequence analysis. CONCLUSIONS The results of this investigation suggest that A. butzleri should be considered an agent that can cause outbreaks of foodborne illness. Rigorous investigation of outbreaks of undetermined etiology is valuable for incrementally increasing our understanding of emerging agents causing foodborne illnesses.

Rifampin-resistant Meningococcal Disease

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 β subunit (rpoB) gene were found in isolates from each rifampin-resistant case-patient.

Subtyping Novel Zoonotic Pathogen Cryptosporidium Chipmunk Genotype I

ABSTRACT Cryptosporidium chipmunk genotype I is an emerging zoonotic pathogen in humans. The lack of subtyping tools makes it impossible to determine the role of zoonotic transmission in epidemiology. To identify potential subtyping markers, we sequenced the genome of a human chipmunk genotype I isolate. Altogether, 9,509,783 bp of assembled sequences in 853 contigs were obtained, with an N50 of 117,886 bp and >200-fold coverage. Based on the whole-genome sequence data, two genetic markers encoding the 60-kDa glycoprotein (gp60) and a mucin protein (ortholog of cgd1_470) were selected for the development of a subtyping tool. The tool was used for characterizing chipmunk genotype I in 25 human specimens from four U.S. states and Sweden, one specimen each from an eastern gray squirrel, a chipmunk, and a deer mouse, and 4 water samples from New York. At the gp60 locus, although different subtypes were seen among the animals, water, and humans, the 15 subtypes identified differed mostly in the numbers of trinucleotide repeats (TCA, TCG, or TCT) in the serine repeat region, with only two single nucleotide polymorphisms in the nonrepeat region. Some geographic differences were found in the subtype distribution of chipmunk genotype I from humans. In contrast, only two subtypes were found at the mucin locus, which differed from each other in the numbers of a 30-bp minisatellite repeat. Thus, Cryptosporidium chipmunk genotype I isolates from humans and wildlife are genetically similar, and zoonotic transmission might play a potential role in human infections.

Evaluation of the positive predictive value of rapid assays used by clinical laboratories in Minnesota for the diagnosis of cryptosporidiosis.

We evaluated the positive predictive value (PPV) of rapid assays used by clinical laboratories in Minnesota to diagnose cryptosporidiosis. The overall PPV was 56% for rapid assays versus 97% for nonrapid assays; clinicians and laboratorians need to be aware of the low PPV of rapid assays when diagnosing cryptosporidiosis.

Norovirus surveillance among callers to foodborne illness complaint hotline, Minnesota, USA, 2011-2013.

Norovirus is the leading cause of foodborne disease in the United States. During October 2011–January 2013, we conducted surveillance for norovirus infection in Minnesota among callers to a complaint-based foodborne illness hotline who reported diarrhea or vomiting. Of 241 complainants tested, 127 (52.7%) were positive for norovirus.

Methicillin-Resistant Staphylococcus aureus at Canoe Camp

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.