Articles from Emerging Infectious Diseases

We reviewed Corynebacterium spp. infection cases reported in South Africa during 2015–2023. We analyzed 84 isolates from 83 patients with C. diphtheriae, as well as 1 C. belfantii and 3 C. ulcerans isolates. Among C. diphtheriae cases, we observed respiratory diphtheria (26/83 patients [31%]), endocarditis (14/83 [17%]), cutaneous diphtheria (22/83 [27%]), nonspecific respiratory illnesses (5/83 [6%]), and asymptomatic carriage (16/83 [19%]). The median patient age was 19 (range 0–88) years. Diphtheria-tetanus-pertussis vaccination was incomplete for 26% (5/19) or unknown for 68% (13/19) of children 0–9 years of age. C. diphtheriae was intermediately resistant to penicillin (82/84 [98%] isolates; MIC₉₀ 0.5 μg/mL) but susceptible to erythromycin (83/84 [99%] isolates; MIC₉₀ 0.25 μg/mL). Eighteen unique sequence types were identified, corroborating C. diphtheriae heterogeneity. Toxin-producing strains were detected among cutaneous and respiratory diphtheria cases, indicating all forms of disease require monitoring and prompt public health action to curb transmission.

Henipaviruses, such as Hendra and Nipah viruses, are major zoonotic pathogens that cause encephalitis and respiratory infections in humans and animals. The recent emergence of Langya virus in China highlights the need to understand henipavirus host diversity and geographic spread to prevent future outbreaks. Our analysis of the National Center for Biotechnology Information Virus and VIRION databases revealed ≈1,117 henipavirus sequences and 142 complete genomes. Bats (64.7%) and shrews (11.7%) dominated the host species record, and the genera Pteropus and Crocidura contained key henipavirus hosts in Asia, Australia, and Africa. Henipaviruses found in the Eidolon bat genus exhibited the highest within-host genetic distance. Phylogenetic analysis revealed batborne and rodent- or shrew-derived henipaviruses diverged ≈11,000 years ago and the first known lineage originating in Eidolon genus bats ≈9,900 years ago. Pathogenic henipaviruses diverged from their ancestors 2,800–1,200 years ago. Including atypical hosts and regions in future investigations is necessary to control future outbreaks.

Candida auris is an emerging fungal pathogen associated with outbreaks in healthcare settings. We report a multiyear outbreak of C. auris in a burn intensive care unit in Illinois, USA, during 2021–2023. We identified 28 C. auris cases in the unit over a 2-year period, despite outbreak response and multimodal mitigation measures. Of the 28 case-patients, 15 (53.6%) were considered colonized and 13 (46.4%) had clinical infections. Phylogenetic analysis of whole-genome sequences revealed 4 distinct clusters of closely related (0–6 SNP differences) genomes containing 3–6 cases. Clusters generally contained temporally related isolates from patients with epidemiologic links; this finding suggests that multiple introductions and within-unit spread over a limited time were responsible for the outbreak, rather than transmission from a long-term source (e.g., persistent environmental contamination or staff carriage). Here, integrated traditional and genomic epidemiology supported C. auris outbreak investigation and response and informed targeted interventions.

Buruli ulcer (BU) is a rare, neglected tropical disease caused by Mycobacterium ulcerans that can lead to severe skin ulcers. To determine the epidemiology of BU in Victoria, Australia, during 2017–2022 we analyzed surveillance data. A total of 1,751 cases of BU were notified; 968 (55%) patients were male and 781 (45%) female (2 were missing sex data), and 984 (56%) resided in established BU-endemic areas, although an increasing number were in new BU-endemic areas. Most cases (83%, 1,301) were classified as category I. Multivariate modeling demonstrated that factors for severe BU included being male, being older, and living in a new BU-endemic or non–BU-endemic area. A relatively shorter interval between first visit to a clinician and receipt of diagnosis was protective against severe disease. The expansion of BU-endemic areas throughout Victoria remains a public health concern and calls for targeted action, particularly for patients and clinicians in new BU-endemic areas.

Reports of human infections with influenza A(H5N1) clade 2.3.4.4b viruses associated with outbreaks in dairy cows in the United States underscore the need to assess the potential cross-protection conferred by existing influenza immunity. We serologically evaluated ferrets previously infected with an influenza A(H1N1)pdm09 virus for cross-reactive antibodies and then challenged 3 months later with either highly pathogenic H5N1 clade 2.3.4.4b or low pathogenicity H7N9 virus. Our results showed that prior influenza A(H1N1)pdm09 virus infection more effectively reduced the replication and transmission of the H5N1 virus than did the H7N9 virus, a finding supported by the presence of group 1 hemagglutinin stalk and N1 neuraminidase antibodies in preimmune ferrets. Our findings suggest that prior influenza A(H1N1)pdm09 virus infection may confer some level of protection against influenza A(H5N1) clade 2.3.4.4.b virus.

A previous study demonstrated noninferior efficacy of 4-month rifapentine/moxifloxacin regimen for tuberculosis (TB) treatment compared with the standard regimen. We explored results among study participants with diabetes. Among 2,516 randomized participants, 181 (7.2%) had diabetes. Of 166 participants with diabetes in the microbiologically eligible analysis group, 26.3% (15/57) had unfavorable outcomes in the control regimen, 13.8% (8/58) in the rifapentine/moxifloxacin regimen, and 29.4% (15/51) in the rifapentine regimen. The difference in proportion of unfavorable outcomes between the control and rifapentine/moxifloxacin arms in the microbiologically eligible analysis group was –12.5% (95% CI –27.0% to 1.9%); the difference between the control and rifapentine arms was 3.1% (95% CI –13.8% to 20.0%). Safety outcomes were similar in the rifapentine/moxifloxacin regimen and control arms. Among participants with TB and diabetes, the rifapentine/moxifloxacin arm had fewest unfavorable outcomes and was safe. Our findings indicate that the rifapentine/moxifloxacin regimen can be used in persons with TB and diabetes.

The emergence of highly pathogenic avian influenza A(H5N1) virus in dairy cattle herds across the United States in 2024 caused several human infections. Understanding the risk for spillover infections into humans is crucial for protecting public health. We investigated whether immunity from influenza A(H1N1)pdm09 (pH1N1) virus would provide protection from death and severe clinical disease among ferrets intranasally infected with H5N1 virus from dairy cows from the 2024 outbreak. We observed differential tissue tropism among pH1N1-immune ferrets. pH1N1-immune ferrets also had little H5N1 viral dissemination to organs outside the respiratory tract and much less H5N1 virus in nasal secretions and the respiratory tract than naive ferrets. In addition, ferrets with pH1N1 immunity produced antibodies that cross-reacted with H5N1 neuraminidase protein. Taken together, our results suggest that humans with immunity to human seasonal influenza viruses may experience milder disease from the 2024 influenza A(H5N1) virus strain.

After detection of 2 clinical lymphatic filariasis (LF) cases in a postelimination context in 2023 on the island of Futuna (Wallis and Futuna archipelago), the Wallis and Futuna Health Agency conducted a LF prevalence survey in Futuna in May 2024. This cross-sectional study, carried out among schoolchildren <18 years of age, identified 5 children with antigenemia, indicating an estimated antigenemia prevalence in Futuna children nearing 2%. The study also confirmed a spatial cluster of cases in the village of Taoa, where the child antigenemia prevalence reached 7.5% (95% CI 2.1%–18.2%), and demonstrated a link between infection and traditional housing. We observed microfilariae in contact cases during secondary investigations. These findings suggest resurgence of LF in a postelimination context, in which the expected child antigenemia prevalence should not exceed 1%. This situation should prompt a new mass drug administration campaign using triple therapy and the reinforcement of epidemiologic and entomologic surveillance.

Outbreak investigation is an essential component of tuberculosis (TB) control in the United States, but its epidemiologic impact and cost-effectiveness have not been quantified. We modeled outbreak investigation activities in the United States during 2023–2032 and estimated corresponding epidemiologic impact, economic costs (in 2022 US$), and incremental cost-effectiveness ratios from the healthcare system perspective (cost per additional quality-adjusted life-year gained). We projected that outbreak investigations would result in 1,030,000 (95% uncertainty interval [UI] 376,000–1,740,000) contacts investigated, leading to 4,130 (95% UI 1,420–7,640) TB diagnoses and 104,000 (95% UI 37,600–181,000) latent TB infection diagnoses, at a total cost of US $219 million (95% UI $80–$387 million). We estimated that 5,560 (95% UI 1,720–11,400) TB cases would be averted through early detection and treatment, and the incremental cost-effectiveness of outbreak investigations, compared with no outbreak investigations, was $27,800 per quality-adjusted life-year gained (95% UI $4,580–$68,700).

Mycobacterium nebraskense infection is rarely encountered; only 7 human cases have been reported worldwide since the initial report of 5 cases in Nebraska, USA, in 2004. We report 9 patients from Connecticut and 2 from Oregon, USA, who had M. nebraskense isolated from respiratory secretions; 7 patients met the American Thoracic Society/Infectious Diseases Society of America criteria for nontuberculous mycobacterial pulmonary disease. In 4 cases, the organism was isolated 1 time and caused brief or no symptoms. Most cases in Connecticut were reported after 2017. Antimicrobial drug susceptibility testing of 6 isolates showed clarithromycin susceptibility. In 2 cases, infection was refractory to treatment. The 9 Connecticut patients lived in 8 different towns; thus, a common water supply did not explain the high frequency of M. nebraskense isolation. M. nebraskense is a clinically significant cause of nontuberculous mycobacterial pulmonary disease in Connecticut; continued surveillance will be needed to determine its frequency and optimum treatment.

In Ethiopia, dengue virus (DENV) infections have been reported in several regions; however, little is known about the genetic diversity of circulating viruses. We conducted clinical surveillance of DENV during the 2023 nationwide outbreak in Ethiopia. We enrolled patients at 3 sentinel hospital sites. Using reverse transcription PCR, we screened serum samples for 3 arboviruses and then serotyped and whole-genome sequenced DENV-positive samples. We detected DENV-1 and DENV-3 serotypes. Phylogenetic analysis identified 1 transmission cluster for DENV-1 (genotype III major lineage A) and 2 clusters for DENV-3 (genotype III major lineage B). The first DENV-3 cluster was closely related to an isolate from a 2023 dengue outbreak in Italy; the second cluster was related to isolates from India. Co-circulation of DENV-1 and DENV-3 in Ethiopia highlights the potential for severe dengue. Intensified surveillance and coordinated public health responses are needed to address the threat of severe dengue outbreaks.

Bedaquiline is a cornerstone drug for treating drug-resistant tuberculosis. We analyzed 11 isolates from 9 patients who were treated with a bedaquiline-based regimen and remained culture-positive long after treatment start. In 4 of 8 resistant isolates, we found substitutions in AtpE, which encodes subunit c of the Mycobacterium tuberculosis ATP synthase and is rarely identified in clinical isolates. We found Ile66Met and Glu61Asp substitutions in 2 cases each. Additional mutations in mmpL5, mmpL4, and atpB genes could affect the susceptibility to bedaquiline. MmpL5(Asn772Thr) emerged during bedaquiline treatment, whereas AtpB(Val165Leu) was found in 1 case simultaneously with the loss-of-function mmpR5 mutation in a susceptible strain. The loss-of-function mutation in the mmpL4 efflux gene was identified in the mixed state, pointing to ongoing selection in a bedaquiline-resistant isolate. Another case of the emergence of the mmpL4 mutation, accompanied by a proportional increase in bedaquiline MIC, was identified by retrospective analysis of genomes from bedaquiline-resistant isolates.

We describe the epidemiology, diagnosis, and management of nontuberculous mycobacterial lymphadenitis cases detailed in a 28-year (1996–2023) multicenter cohort from Spain. The case numbers remained stable during the initial prospective phase (2013–2020), but a sharp decline was observed during 2021–2022. Disease onset occurred during spring or June in 45.9% of cases. Mycobacterium avium complex (43.1%) and M. lentiflavum (39.9%) were the most common species detected. M. lentiflavum affected mostly younger children from central Spain. The most common treatment strategy was complete surgical resection with (n = 80) or without (n = 88) antimicrobial drug treatment, followed by antimicrobial drugs alone (n = 76). Facial palsy developed in 10.4% of surgical cases. Adverse events because of antimicrobial drugs were uncommon. New fistula formation during follow-up occurred more in children managed with observation alone than in those treated with antimicrobial drugs alone (relative risk 2.7 [95% CI 1.3–5.3]; p = 0.014).

After 3 cases of Corynebacterium diphtheriae infection associated with intravenous drug use among persons experiencing homelessness (PEH) were reported to the Health Protection Authority in Frankfurt am Main, Germany, in 2023, we examined pathogen spread among PEH. Furthermore, we investigated a possible link with the 2022 outbreak of diphtheria in Europe. From swab samples collected during August–November 2023 from 36 PEH and cutaneous lesions, we detected 3 additional cases of cutaneous toxigenic C. diphtheriae. Sequence type 574 was identified in 5 case-isolates and is genetically associated with 1 of the predominant clusters in identified in the 2022 outbreak. Our findings demonstrate the need for increased detection and monitoring of cutaneous diphtheria and boosting immunity against diphtheria in groups with increased risk for infection. Genomic analyses are valuable for identifying genetic relationships between outbreaks, even when epidemiologic data are scarce.

Mycoplasma pneumoniae infections decreased in Ohio, USA, during the COVID-19 pandemic but reemerged in 2023; >2,000 cases were reported during September 2023­–September 2024. Of 995 M. pneumoniae–positive samples, 24 (2.4%) had mutations for macrolide-resistant M. pneumoniae (MRMp). MRMp rates are low but increasing. MRMp surveillance is crucial for monitoring antimicrobial resistance.

To elucidate the epidemiology of Sarcocystis spp. parasites in human intestinal infections, we used high-throughput sequencing to investigate human intestinal sarcocystosis cases identified by microscopy in France during 2021–2024. Our results indicate that humans are a definitive host of S. sigmoideus parasites and that occurrence of multiple species in 1 patient is common.

During January–September 2024, a national active case-finding program in Peru’s prisons screened >38,000 persons for tuberculosis (TB) using chest radiography with automated interpretation and rapid molecular tests. The program found high percentages of TB, rifampin-resistant TB, and asymptomatic infections, demonstrating the urgent need for systematic screening among incarcerated populations.

We describe emergence of Buruli ulcer in urban Geelong, Victoria, Australia, and examine timing and proximity of human cases to detection of Mycobacterium ulcerans DNA in possum feces. M. ulcerans–positive feces preceded human cases by up to 39 months, constituting an early warning of impending risk for Buruli ulcer.

We quantified presumptive extended-spectrum β-lactamase–producing Escherichia coli and Klebsiella, Enterobacter, Serratia, and Citrobacter group colonies from wastewater in Basel, Switzerland, across 3 years to represent before, during, and after the COVID-19 pandemic. Wastewater surveillance might be a noninvasive, sensitive, rapid, and cost-effective instrument for early detection and monitoring local epidemiology.

Two unvaccinated infants residing in the same borough of New York, New York, USA, had Haemophilus influenzae type b meningitis develop 1 year apart. Whole-genome sequencing and phylogenetic analysis revealed the isolates shared a previously undescribed multilocus sequence type and were more closely related to each other than to other sequenced strains.

Complement C5 inhibitors bring an increased risk for Neisseria infections. A novel complement C3 inhibitor, pegcetacoplan, was recently approved to treat paroxysmal nocturnal hemoglobinuria, a condition commonly treated with complement C5 inhibitors. We present a case of meningococcal sepsis in a pegcetacoplan-treated patient with aplastic anemia and paroxysmal nocturnal hemoglobinuria.

Tickborne infections are challenging to diagnose, particularly among solid organ transplant recipients. We report a US case of donor-derived ehrlichiosis from a living kidney donation that highlights how screening for living donors may miss tickborne infections. Clinicians should consider the epidemiology of the donor when screening donations and evaluating recipients for donor-derived infection.

We explored the role of commensal Neisseria in the emergence of third-generation cephalosporin-resistant N. meningitidis. Cefotaxime resistance–conferring penA795 was prevalent among commensal Neisseria isolates in Shanghai, China, and was acquired by a serogroup C quinolone-resistant sequence type 4821 N. meningitidis, Nm507, causing fulminant meningitis in an unvaccinated 2-year-old child.

Tsukamurella spp. are an infrequent and underdiagnosed cause of bacterial respiratory infection, usually occurring in patients with structural lung disease or immune compromise. We describe T. tyrosinosolvens respiratory infection in a patient in Australia without structural lung disease or known immune deficiency. The patient was successfully treated with oral ciprofloxacin and clarithromycin.

To reconstruct transmission chains of the multidrug-resistant tuberculosis Ch strain, which harbors a unique combination of resistance mutations, we analyzed genomes of 25 isolates from 12 patients with diagnosis during 2006–2022 in Chaco Province, Argentina. Amplification of resistance, high mortality rates, and indications of a wider outbreak raise concerns for surveillance programs.

Rifampin-resistant Mycobacterium tuberculosis was identified by the World Health Organization as a pathogen of public health critical importance. During 2014–2023, an increase in fluoroquinolone resistance in rifampin-resistant M. tuberculosis from Kharkiv, Ukraine, was observed. Efforts to mitigate factors contributing to resistance should be prioritized to prevent further escalation of that threat.

Sarcocystis is a genus of protozoan parasites that can infect various vertebrates. In humans, Sarcocystis infection usually is asymptomatic but might manifest as a mild gastroenteritis or extraintestinal myositis. We report a case of human central nervous system infection in Norway caused by S. nesbitti parasites.

Given recent outbreaks of Oropouche virus in Latin America and >100 confirmed travel-associated cases in the United States, we evaluated the competence of US vectors, including Aedes albopictus, Culex quinquefasciatus, Culex pipiens, and Anopheles quadrimaculatus mosquitoes. Results with historic and recent isolates suggest transmission potential for those species is low.

We detected neutralizing antibodies, viral RNA, and sialic acid receptors for Alphainfluenzavirus influenzae in urban coatis (Nasua nasua) in Brazil, suggesting exposure and susceptibility. We used hemagglutination inhibition, reverse transcription quantitative PCR, and histochemistry for detection. Increased epidemiologic wildlife surveillance would improve influenza A emergency event response.

We identified 2 novel species, Mycobacterium novusgordonae and M. shingordonae, from sputum specimens of pulmonary disease patients in Japan. Genetic and biochemical analyses revealed a close relationship with M. paragordonae. One M. shingordonae case-patient experienced severe progressive infection, highlighting the variation in pathogenicity of the M. gordonae clade species.

In a longitudinal study in a first-level hospital in Luanda, Angola, we found rifampin-resistant and multidrug-resistant tuberculosis (TB) in 38 (8%, 95% CI 5.7–10.8) of 474 patients with no previous history of TB. Of note, 2 patients (0.4%, 95% CI 0.1–1.5) demonstrated pre–extensively drug-resistant TB.

We report avian Chlamydia abortus pneumonia in an immunocompetent elderly patient in the Netherlands after environmental exposure to wild aquatic birds, including seabirds. New molecular surveillance studies are needed in wild and captive birds, as well as increased awareness to establish occurrence, clinical manifestations, and geographic distribution of this rare zoonotic disease.

High-dose isoniazid is recommended to treat multidrug-resistant tuberculosis (MDR TB). Among 958 MDR TB isolates identified in France during 2008–2022, 93.1% exhibited high-level isoniazid resistance, and molecular testing showed limited diagnostic accuracy in predicting resistance. Clinicians should reconsider using high-dose isoniazid in MDR TB treatment because of suboptimal effect and toxicity concerns.

Projections for the US 2023–24 respiratory virus season indicated a 31% decrease to a 55% increase in hospitalizations for respiratory syncytial virus, influenza, and COVID-19 compared with 2022–23, depending on circulating variants and vaccination uptake. The projections captured the tripledemic peak but missed the multiwave seasonality of COVID-19.

In 2020, fecal (stool) testing was recommended for diagnosing Mycobacterium tuberculosis complex (MTBC) infection in children by using the Cepheid Xpert MTB/RIF assay; since then, countries have begun implementing stool-based testing, often as part of a comprehensive strategy to enhance TB case finding among children. On the basis of an experience-sharing workshop in November 2023, we determined insights of 9 early-adopter countries. Across those countries, 71,757 children underwent stool testing over a combined period of 121 months, October 2020–September 2023. A total of 2,892 children were positive for MTBC, and rifampin resistance was confirmed for 43 stool samples. The overall yield of MTBC detection across the countries was 4.1% (range 1.1%–17.3%). Stool collection for Xpert testing was considered noninvasive and as easy as sputum testing. Stool-based testing can be integrated into peripheral healthcare levels as a routine test to increase bacteriologic confirmation among children with presumptive TB.

A previous study demonstrated noninferior efficacy of 4-month rifapentine/moxifloxacin regimen for tuberculosis (TB) treatment compared with the standard regimen. We explored results among study participants with diabetes. Among 2,516 randomized participants, 181 (7.2%) had diabetes. Of 166 participants with diabetes in the microbiologically eligible analysis group, 26.3% (15/57) had unfavorable outcomes in the control regimen, 13.8% (8/58) in the rifapentine/moxifloxacin regimen, and 29.4% (15/51) in the rifapentine regimen. The difference in proportion of unfavorable outcomes between the control and rifapentine/moxifloxacin arms in the microbiologically eligible analysis group was –12.5% (95% CI –27.0% to 1.9%); the difference between the control and rifapentine arms was 3.1% (95% CI –13.8% to 20.0%). Safety outcomes were similar in the rifapentine/moxifloxacin regimen and control arms. Among participants with TB and diabetes, the rifapentine/moxifloxacin arm had fewest unfavorable outcomes and was safe. Our findings indicate that the rifapentine/moxifloxacin regimen can be used in persons with TB and diabetes.

Human ehrlichiosis is a potentially fatal tickborne disease caused by 3 species: Ehrlichia chaffeensis, E. ewingii, and E. muris eauclairensis. In the United States, 234 confirmed cases of E. ewingii ehrlichiosis were reported to the Centers for Disease Control and Prevention through the National Notifiable Diseases Surveillance System during 2013–2021; average annual incidence was 0.08 cases/1 million population. E. ewingii ehrlichiosis was reported more commonly among older, White, non-Hispanic, and male patients. Incidence and case counts generally increased yearly, except for 2020 and 2021. The highest number of cases were reported from Missouri and Arkansas. We report the geographic expansion of E. ewingii ehrlichiosis and the continued public health challenge of clarifying clinical manifestations of this infection. Clinician education will be essential to implement molecular assays to properly diagnose E. ewingii infection in patients and gain a better understanding of the epidemiology of this emerging disease.

A global increase in the incidence of invasive group A Streptococcus (iGAS) infections was observed after lifting of COVID-19 related restrictions in 2022, and type M1_UK dominated in many countries. After seasonal declines in iGAS incidence during the summer of 2023, simultaneous, rapid expansion of a previously rare emm type 3.93 was seen beginning in November, increasing to 20% of all cases in England and 60% of all cases in the Netherlands within 4 months. emm3.93 was associated with iGAS in children 6–17 years of age and with increased risk for pneumonia or pleural empyema and meningitis in both countries. No excess risk of death was identified for emm3.93 compared with other types. Genomic analysis of historic and contemporary emm3.93 isolates revealed the emergence of 3 new clades with a potentially advantageous genomic configuration. Our findings demonstrate the value of molecular surveillance, including long-read sequencing, in identifying clinical and public health threats.

Rickettsia sibirica mongolitimonae is an emerging cause of tickborne rickettsiosis. Since the bacterium was first documented as a human pathogen in 1996, a total of 69 patients with this infection have been reported in the literature. Because of the rising rate of R. sibirica mongolitimonae infection cases, we evaluated the epidemiologic and clinical features of 29 patients who had R. sibirica mongolitimonae infections confirmed during 2007–2024 at the Center for Rickettsiosis and Arthropod-Borne Diseases, the reference laboratory of San Pedro University Hospital–Center for Biomedical Research of La Rioja, Logroño, Spain. We also reviewed all cases published in the literature during 1996–2024, evaluating features of 94 cases of R. sibirica mongolitimonae infection (89 in Europe, 4 in Africa, and 1 in Asia). Clinicians should consider R. sibirica mongolitimonae as a potential causative agent of rickettsiosis, and doxycycline should be administered promptly to avoid clinical complications.

Streptococcus pneumoniae infection is considered an uncommon cause of arthritis in adults. To determine the clinical and microbiological characteristics of pneumococcal septic arthritis, we retrospectively studied a large series of cases among adult patients during the 2010–2018 conjugate vaccine era in France. We identified 110 patients (56 women, 54 men; mean age 65 years), and cases included 82 native joint infections and 28 prosthetic joint infections. Most commonly affected were the knee (50/110) and hip (25/110). Concomitant pneumococcal infections were found in 37.2% (38/102) and bacteremia in 57.3% (55/96) of patients, and underlying conditions were noted for 81.4% (83/102). Mortality rate was 9.4% (8/85). The proportion of strains not susceptible to penicillin was 29.1% (32/110). Of the 55 serotyped strains, 31 (56.4%) were covered by standard pneumococcal vaccines; however, several nonvaccine serotypes (mainly 23B, 24F, and 15A) had emerged, for which susceptibility to β-lactams was low.

The Ebola virus disease (EVD) outbreak of 2013–2016 was large, leaving in its wake an estimated 17,000 survivors in West Africa. Uveitis is one of the most common ophthalmic manifestations of EVD, but long-term follow-up in the at-risk population is lacking. We conducted a retrospective cross-sectional study of 521 EVD survivors from Sierra Leone who underwent comprehensive ophthalmic examination a median of 1,289 days, or ≈3.5 years, after discharge from Ebola treatment units. The most common ophthalmic findings were cataracts (117 eyes, 11.2%), uveitis (86 eyes, 8.3%), dry eyes (81 eyes, 7.8%), and chorioretinal scar (68 eyes, 6.5%). EVD survivors with cataracts, uveitis, optic neuropathy, and corneal scar were more likely to have vision impairment, defined as Snellen visual acuity worse than 20/50. Results of our study highlight the need for ongoing vision care in EVD survivors.

Congregate homeless shelters are disproportionately affected by infectious disease outbreaks. We describe enterovirus epidemiology across 23 adult and family shelters in King County, Washington, USA, during October 2019–May 2021, by using repeated cross-sectional respiratory illness and environmental surveillance and viral genome sequencing. Among 3,281 participants >3 months of age, we identified coxsackievirus A21 (CVA21) in 39 adult residents (3.0% [95% CI 1.9%–4.8%] detection) across 7 shelters during October 2019–February 2020. We identified enterovirus D68 (EV-D68) in 5 adult residents in 2 shelters during October–November 2019. Of 812 environmental samples, 1 was EV-D68–positive and 5 were CVA21–positive. Other enteroviruses detected among residents, but not in environmental samples, included coxsackievirus A6/A4 in 3 children. No enteroviruses were detected during April 2020–May 2021. Phylogenetically clustered CVA21 and EV-D68 cases occurred in some shelters. Some shelters also hosted multiple CVA21 lineages.

Mycobacterium abscessus infection is challenging to treat. Extrapulmonary M. abscessus infections (EP-MAB) are less common than pulmonary M. abscessus infections. To evaluate treatment regimens, we retrospectively analyzed consecutive microbiologically confirmed EP-MAB cases diagnosed in France during 2012–2020. We studied 45 patients with EP-MAB, including 14 bone and joint infections, 10 skin and soft tissue infections, and 8 lymph node infections. Most (62%) patients had no reported immunodeficiency. In 27 patients, EP-MAB followed healthcare-associated (44%) or environmental (16%) injuries. Of the 45 isolates, 25 were subspecies abscessus, 10 bolletii, and 9 massiliense; 1 was unidentified. Cure was achieved for 36 (80%) patients who received a median antimicrobial regimen of 6 months; 22 (55%) also underwent surgery. Four patients died, and 5 were unavailable for follow-up. EP-MAB predominantly affects immunocompetent patients after an injury; outcomes are favorable. We propose a >6-month regimen of antimicrobial therapy with consideration for surgery and regular patient reassessment.

Pasteurella spp. can cause fatal zoonotic infections in humans. We performed a multicenter study to investigate the prevalence and clinical features of Pasteurella infections in South Korea during 2018‒2022. We also conducted a collaborative systematic review and meta-analysis of the global burden of Pasteurella bacteremia. The study included 283 cases found an increasing trend in Pasteurella infections. Blood cultures were positive in 8/35 (22.9%) cases sampled, for overall bacteremia-associated rate of 2.8% (8/283). Aging was a significant risk factor for bacteremia (odds ratio 1.05 [95% CI 1.01–1.10]), according to multivariate analyses. For the meta-analysis, we included a total of 2,012 cases from 10 studies. The pooled prevalence of bacteremia was 12.4% (95% CI 7.3%–18.6%) and of mortality 8.4% (95% CI 2.7%–16.5%). Our findings reflect the need for greater understanding of the increase in Pasteurella infections and the global burden of Pasteurella bacteremia to determine appropriate case management.

We investigated differences in risk factors and preventive behaviors by age and sex among persons with reported Lyme disease in Ontario, Canada, during 2015–2022. Incidence rates peaked among children 5–9 and adults 50–79 years of age. Median age was higher for female than male case-patients (54 vs. 51 years). Male case-patients reported more activity in wooded and tall grass areas than did female case-patients; fewer male case-patients reported sharing living space with outdoor-exposed companion animals. As age increased, more case-patients reported activity in blacklegged tick habitats, exposure to ticks, and wearing adequate clothing, but fewer reported sharing living space with outdoor-exposed companion animals. Adoption of preventive behaviors was relatively low and did not differ by sex. Male case-patients, children 5–9 years of age and their parents or caregivers, and adults >59 years of age represent populations that would benefit from tailored public health messaging on Lyme disease prevention.

We conducted a prospective study of 159 cases of Streptococcus dysgalactiae subspecies equisimilis (SDSE) bacteremia in 157 patients at 2 hospitals in Finland during November 2015–November 2019. Cellulitis was associated with nonsevere disease (p = 0.008); necrotizing fasciitis was associated with severe disease (p = 0.004). Fifty percent of patients had >1 clinical characteristic associated with risk for death. The case-fatality rate was 6%, and 7% of patients were treated in an intensive care unit. Blood leukocyte counts on days 2 (p = 0.032) and 3 (p = 0.020) and C-reactive protein levels on days 3 (p = 0.030) and 4 (p = 0.009) after admission were predictors of severe disease. The Pitt bacteremia score was an accurate predictor of death. Using the Pitt bacteremia score, leukocyte counts, and CRP responses during initial treatment can improve treatment strategies and survival for patients with SDSE.

Evidence on mortality rates and causes of death associated with extrapulmonary nontuberculous mycobacteria (NTM) infection is limited. This nationwide register-based study in Denmark used diagnostic codes to match adult patients with extrapulmonary NTM infection 1:4 to controls. During 2000–2017, we identified 485 patients, who had significantly more comorbidities than controls. The 5-year mortality rate for patients was 26.8% (95% CI 23.1%–31.0%) and for controls, 10.9% (95% CI 9.6%–12.4%). The median age at death was 76 (interquartile range 63–85) years for patients and 84 (interquartile range 73–90) years for controls. The adjusted hazard rate of death for patients was 1.34 (95% CI 1.10–1.63; p = 0.004). Patients and controls mainly died of cardiovascular disease and solid malignant neoplasms. Hematologic malignancies and HIV were more frequently causes of death in patients. Mortality rates are substantial among patients with extrapulmonary NTM infection, predominantly caused by underlying conditions.

Human infections with Corynebacterium diphtheriae species complex (CdSC) bacteria were rare in French Guiana until 2016, when the number of cases diagnosed increased. We conducted an epidemiologic, multicenter, retrospective study of all human CdSC infections diagnosed in French Guiana during January 1, 2016–December 31, 2021. A total of 64 infectious episodes were observed in 60 patients; 61 infections were caused by C. diphtheriae and 3 by C. ulcerans. Estimated incidence increased from 0.7 cases/100,000 population in 2016 to 7.7 cases/100,000 population in 2021. The mean patient age was 30.4 (+23.7) years, and male-to-female ratio was 1.7:1 (38/22). Of the 61 C. diphtheriae isolates, 5 tested positive for the diphtheria toxin gene, and all results were negative by Elek test; 95% (61/64) of cases were cutaneous, including the C. ulcerans cases. The increase in reported human infections underscores the need to raise awareness among frontline healthcare practitioners to improve prevention.

Archaea represent a separate domain of life, next to bacteria and eukarya. As components of the human microbiome, archaea have been associated with various diseases, including periodontitis, endodontic infections, small intestinal bacterial overgrowth, and urogenital tract infections. Archaea are generally considered nonpathogenic; the reasons are speculative because of limited knowledge and gene annotation challenges. Nevertheless, archaeal syntrophic principles that shape global microbial networks aid both archaea and potentially pathogenic bacteria. Evaluating archaea interactions remains challenging, requiring clinical studies on inflammatory potential and the effects of archaeal metabolism. Establishing a culture collection is crucial for investigating archaea functions within the human microbiome, which could improve health outcomes in infectious diseases. We summarize potential reasons for archaeal nonpathogenicity, assess the association with infectious diseases in humans, and discuss the necessary experimental steps to enable mechanistic studies involving archaea.

Xenotransplantation, transplantation into humans of vascularized organs or viable cells from nonhuman species, is a potential solution to shortages of transplantable human organs. Among challenges to application of clinical xenotransplantation are unknown risks of transmission of animal microbes to immunosuppressed recipients or the community. Experience in allotransplantation and in preclinical models suggests that viral infections are the greatest concern. Worldwide, the distribution of swine pathogens is heterogeneous and cannot be fully controlled by international agricultural regulations. It is possible to screen source animals for potential human pathogens before procuring organs in a manner not possible within the time available for surveillance testing in allotransplantation. Infection control measures require microbiological assays for surveillance of source animals and xenograft recipients and research into zoonotic potential of porcine organisms. Available data suggest that infectious risks of xenotransplantation are manageable and that clinical trials can advance with appropriate protocols for microbiological monitoring of source animals and recipients.

We conducted surveillance for carbapenem-resistant Enterobacterales (CRE) during 2016–2020 at 10 US sites and extended-spectrum β-lactamase–producing Enterobacterales (ESBL-E) during 2019–2020 at 6 US sites. Among 159 CRE cases in children (median age 5 years), CRE was isolated from urine for 131 (82.4%) and blood from 20 (12.6%). Annual CRE incidence rate (cases/100,000 population) was 0.47–0.87. Among 207 ESBL-E cases in children (median age 6 years), ESBL-E was isolated from urine of 196 (94.7%) and blood of 8 (3.9%). Annual ESBL-E incidence rate was 26.5 in 2019 and 19.63 in 2020. CRE and ESBL-E rates were >2-fold higher among infants than other age groups. Most CRE and ESBL-E cases were healthcare-associated community-onset (68 [43.0%] for CRE vs. 40 [23.7%] for ESBL-E) or community-associated (43 [27.2%] for CRE vs. 109 [64.5%] for ESBL-E). Programs to detect, prevent, and treat multidrug-resistant infections must include pediatric populations (particularly the youngest) and outpatient settings.

Crimean-Congo hemorrhagic fever (CCHF) is a tickborne infection that can range from asymptomatic to fatal and has been described in >30 countries. Early identification and isolation of patients with suspected or confirmed CCHF and the use of appropriate prevention and control measures are essential for preventing human-to-human transmission. Here, we provide an overview of the epidemiology, clinical features, and prevention and control of CCHF. CCHF poses a continued public health threat given its wide geographic distribution, potential to spread to new regions, propensity for genetic variability, and potential for severe and fatal illness, in addition to the limited medical countermeasures for prophylaxis and treatment. A high index of suspicion, comprehensive travel and epidemiologic history, and clinical evaluation are essential for prompt diagnosis. Infection control measures can be effective in reducing the risk for transmission but require correct and consistent application.

Crimean-Congo hemorrhagic fever virus (CCHFV) is the most geographically widespread tickborne viral infection worldwide and has a fatality rate of up to 62%. Despite its widespread range and high fatality rate, no vaccines or treatments are currently approved by regulatory agencies in the United States or Europe. Supportive treatment remains the standard of care, but the use of antiviral medications developed for other viral infections have been considered. We reviewed published literature to summarize the main aspects of CCHFV infection in humans. We provide an overview of diagnostic testing and management and medical countermeasures, including investigational vaccines and limited therapeutics. CCHFV continues to pose a public health threat because of its wide geographic distribution, potential to spread to new regions, propensity for genetic variability, potential for severe and fatal illness, and limited medical countermeasures for prophylaxis and treatment. Clinicians should become familiar with available diagnostic and management tools for CCHFV infections in humans.

During October 2021–June 2023, a total of 392 cases of acute hepatitis of unknown etiology in children in the United States were reported to Centers for Disease Control and Prevention as part of national surveillance. We describe demographic and clinical characteristics, including potential involvement of adenovirus in development of acute hepatitis, of 8 fatally ill children who met reporting criteria. The children had diverse courses of illness. Two children were immunocompromised when initially brought for care. Four children tested positive for adenovirus in multiple specimen types, including 2 for whom typing was completed. One adenovirus-positive child had no known underlying conditions, supporting a potential relationship between adenovirus and acute hepatitis in previously healthy children. Our findings emphasize the importance of continued investigation to determine the mechanism of liver injury and appropriate treatment. Testing for adenovirus in similar cases could elucidate the role of the virus.

In 2022, concurrent outbreaks of hepatitis A, invasive meningococcal disease (IMD), and mpox were identified in Florida, USA, primarily among men who have sex with men. The hepatitis A outbreak (153 cases) was associated with hepatitis A virus genotype IA. The IMD outbreak (44 cases) was associated with Neisseria meningitidis serogroup C, sequence type 11, clonal complex 11. The mpox outbreak in Florida (2,845 cases) was part of a global epidemic. The hepatitis A and IMD outbreaks were concentrated in Central Florida and peaked during March–­June, whereas mpox cases were more heavily concentrated in South Florida and had peak incidence in August. HIV infection was more common (52%) among mpox cases than among hepatitis A (21%) or IMD (34%) cases. Where feasible, vaccination against hepatitis A, meningococcal disease, and mpox should be encouraged among at-risk groups and offered along with program services that target those groups.