Clinical presentation, antimicrobial resistance, and treatment outcomes of Aeromonas human infections: A 14-year retrospective study and comparative genomics of two isolates from fatal cases

BACKGROUND

Aeromonas virulence may not be entirely dependent on the host immune status. Pathophysiologic determinants of disease progression and severity remain unclear.

METHODS

One hundred five patients with Aeromonas infections and 112 isolates were identified, their clinical presentations and outcomes analyzed, and their antimicrobial resistance (AMR) patterns assessed. Two isolates (A and B) from fatal cases of Aeromonas dhakensis bacteremia were characterized using whole genome sequence analysis. Virulence factor- and AMR-encoding genes from these isolates were compared with a well-characterized diarrheal isolate A. dhakensis SSU, and environmental isolate A. hydrophila ATCC_7966T.

RESULTS

Skin and soft tissue infections, traumatic wound infections, sepsis, burns, and intraabdominal infections were common. Diabetes, malignancy, and cirrhosis were frequent comorbidities. Male sex, age ≥ 65 years, hospitalization, burns, and intensive care were associated with complicated disease. High rates of AMR to carbapenems and piperacillin-tazobactam were found. Treatment failure was observed in 25.7% of cases. Septic shock and hospital-acquired infections were predictors of treatment failure. All four isolates harbored assorted broad-spectrum AMR genes including blaOXA, ampC, cphA, and efflux pumps. Only clinical isolates possessed both polar and lateral flagellar genes, genes for various surface adhesion proteins, type 3- and -6 secretion systems and their effectors, and toxin genes, including exotoxin A. Both isolates A and B were resistant to colistin and harbored the mobile colistin resistance-3 (mcr-3) gene.

CONCLUSIONS

Empirical therapy tailored to local Aeromonas antibiograms may facilitate more favorable outcomes, while advanced diagnostic methods may aid in identifying correct Aeromonas spp. of significant clinical importance.

Single-center investigation on central-line-associated bloodstream infections and blood-culture contamination during the early months of the coronavirus disease 2019 (COVID-19) pandemic

In this retrospective cohort study, we assessed central-line-associated bloodstream infections (CLABSIs) and blood-culture contamination frequency during the first pandemic wave. Coronavirus disease 2019 (COVID-19) was significantly associated with CLABSI and blood-culture contamination. In the COVID-19 cohort, malignancy was associated with CLABSI. Black race, end-stage renal disease, and obesity were associated with blood-culture contamination.

Ischemic brain infarcts and vasculitis in histoplasmosis of the central nervous system: A case report and review of the literature

Histoplasmosis is one of the most common endemic mycoses affecting immunocompromised individuals in the United States and Latin America. Involvement of the central nervous system carries higher mortality rates and worse prognosis, given its resemblance to stroke, vasculitis, and meningitis of other etiologies. The diagnosis is challenging, due to its subtle clinical presentation and the poor sensitivity of the cerebrospinal fluid culture. Herein the authors present a case of a middle-aged man with HIV, who presented with intermittent headaches exacerbated by an oculomotor nerve palsy, concerning for acute stroke. A diagnosis of central nervous system histoplasmosis was made, and his neurological deficits subsided after initiation of treatment. The stroke-like syndrome in this scenario may be secondary to granulomatous vasculitis of small caliber cerebral blood vessels. Histoplasmosis of the central nervous system remains a challenging diagnosis, which requires a high index of suspicion by the clinician for an early institution of therapy in order to improve outcomes.

1269. Infection, Clinical Syndromes and Antimicrobial Resistance by Aeromonas species: 13-Year Experience with an Emerging Pathogen at a Tertiary Care Center

Background

Aeromonas spp. are emerging pathogens that cause a wide breadth of clinical syndromes, ranging from acute gastroenteritis to skin and soft tissue infections, sepsis, and “flesh-eating” necrotizing fasciitis. Aeromonads have been associated with natural disasters and have predominance in estuarine ecosystems, generating a negative impact on the fishing industry and aquaculture, as well as morbidity and mortality in human populations at risk. Antimicrobial resistance patterns differ by geographic locations worldwide, and studies to guide the therapy in the era of multidrug resistance are lacking in the US.

Methods

A retrospective case series was designed to chart review all adult subjects who had culture proven Aeromonas spp. infections during the period 2008-2020. Demographic data, water exposure, clinical syndromes on presentation, origin (community-acquired vs. nosocomial) and severity of infection, antibiograms, empirical antibiotics, time-to-appropriate therapy, and treatment outcomes were collected.

Results

Eighty-two subjects were included in the analysis. Demographic and clinical data is summarized in Table 1. Near 20% individuals had water exposure, including 53% of those with traumatic wound infections. Skin and soft tissue infection (including traumatic and surgical wound infections) was the most frequent clinical syndrome (51.2%). Sepsis was present on admission in 33% inpatients. Appropriate antibiotics were instituted in a median of 2 days (IQR=1-5), and the most prescribed empiric agents were piperacillin-tazobactam (48%) and meropenem (13.3%). Most isolates were susceptible to cefepime (70/71, 98.6%), levofloxacin (72/78, 92.3%) and TMP-SMX (69/78, 88.5%). Resistance to meropenem was reported in 18/31 isolates (58.1%) after 2015. Treatment failure was identified in 32.3% cases.

Most cases (55%) were encountered during the months of spring and summer, which have warmer temperatures and seasonal heavy rains. Tropical storms caused significant flooding in the Galveston Bay area and Southeast Texas during the summer of 2015, which interestingly coincides with the high number of cases. However, following Hurricane Ike in 2008 or Hurricane Harvey in 2017, the number of cases did not significantly increase.

Conclusion

Aeromonads are emerging pathogens that cause mainly intraabdominal and skin and soft tissue infections. Their incidence is seasonal (55% cases in spring and summer) and it is associated with water exposure in more than half of those with traumatic wound infections. In subjects with specific risk factors, the use of carbapenem-sparing strategies, such as 3^rd or 4^th generation cephalosporins, fluoroquinolones or TMP-SMX, may improve outcomes.

Disclosures

All Authors: No reported disclosures

Strongyloides stercoralis infection after the use of emergency corticosteroids: a case report on hyperinfection syndrome

BACKGROUND

In clinical practice, identification of a case of severe asthma exacerbation prompts initiation of corticosteroids. However, not all that wheezes is asthma.

CASE PRESENTATION

A 61-year-old man from the Peruvian Amazon presented with progressive dyspnea, abdominal pain, and cough for the past week. His medical history was remarkable for asthma since childhood; he was treated with beta-agonists, ipratropium, and orally administered corticosteroids. On evaluation, he was febrile and ill-appearing. His chest examination revealed diffuse wheezing and bilateral crackles. He was diagnosed as having community-acquired pneumonia and asthma exacerbation and was started on empiric antibiotics, nebulized beta-agonists, and orally administered corticosteroids. His clinical status continued deteriorating and he became critically ill despite broad-spectrum antibiotics and antifungals. Considering the epidemiological background of our patient, bronchoalveolar and fecal samples were obtained to investigate soil-transmitted helminths. Larvae of Strongyloides stercoralis were found in both specimens. Ivermectin was initiated and corticosteroids were discontinued. He experienced remarkable improvement of clinical condition over the next weeks. The literature on this topic was reviewed.

CONCLUSION

Cases of severe asthma exacerbation warrant careful evaluation before the initiation of corticosteroids, especially in patients at risk for parasitic infections. A high index of suspicion is critical. Alternative etiologies of respiratory decompensation should be considered in patients who fail to improve with broad-spectrum antibiotics and antifungals.

Strongyloides stercoralis hyperinfection syndrome: a deeper understanding of a neglected disease

Strongyloides stercoralis hyperinfection syndrome (SHS) is a life-threatening condition that warrants early detection and management. We describe the pathogenesis, organ-specific clinical manifestations, and risk factors associated to this condition. A comprehensive review of the literature was conducted in PubMed, LILACS, EBSCO and SciELO by using the keywords: "hyperinfection syndrome"; "Strongyloides stercoralis"; "disseminated strongyloidiasis"; "systemic strongyloidiasis", "pathogenesis" and "pathophysiology". Relevant articles on this topic were evaluated and included by consensus. Also, a secondary search of the literature was performed. Articles in English and Spanish language were included. SHS has been described in tropical and sub-tropical regions. However, there is growing evidence of cases detected in developed countries favored by increasing migration and the advance in immunosuppressive therapies for oncologic and inflammatory diseases. SHS is characterized by massive multiplication of larvae, typically in immunocompromised hosts. Clinical manifestations vary according to the organ involved and include diarrhea, intestinal bleeding, alveolar hemorrhages, heart failure, jaundice, bacteremia among others. Despite advances in the understanding of this condition, fatality rates are near 90%. Clinicians should consider SHS in the differential diagnosis of acutely ill patients with multiple organ damage and epidemiological risk factors. Adverse outcomes are common, especially with delayed anti-parasitic treatment.

Allele-specific differences in transcriptome, miRNome, and mitochondrial function in two hypertrophic cardiomyopathy mouse models

Hypertrophic cardiomyopathy (HCM) stems from mutations in sarcomeric proteins that elicit distinct biophysical sequelae, which in turn may yield radically different intracellular signaling and molecular pathologic profiles. These signaling events remain largely unaddressed by clinical trials that have selected patients based on clinical HCM diagnosis, irrespective of genotype. In this study, we determined how two mouse models of HCM differ, with respect to cellular/mitochondrial function and molecular biosignatures, at an early stage of disease. We show that hearts from young R92W-TnT and R403Q-αMyHC mutation-bearing mice differ in their transcriptome, miRNome, intracellular redox environment, mitochondrial antioxidant defense mechanisms, and susceptibility to mitochondrial permeability transition pore opening. Pathway analysis of mRNA-sequencing data and microRNA profiles indicate that R92W-TnT mutants exhibit a biosignature consistent with activation of profibrotic TGF-β signaling. Our results suggest that the oxidative environment and mitochondrial impairment in young R92W-TnT mice promote activation of TGF-β signaling that foreshadows a pernicious phenotype in young individuals. Of the two mutations, R92W-TnT is more likely to benefit from anti-TGF-β signaling effects conferred by angiotensin receptor blockers and may be responsive to mitochondrial antioxidant strategies in the early stage of disease. Molecular and functional profiling may therefore serve as aids to guide precision therapy for HCM.

Kato-Katz and Lumbreras rapid sedimentation test to evaluate helminth prevalence in the setting of a school-based deworming program

The sensitivity of the Kato-Katz test is suboptimal for the evaluation of intestinal helminth prevalence. Moreover, during mass deworming, as helminth egg burden decreases, the sensitivity is likely to decrease. The Lumbreras rapid sedimentation (Lumbreras) is a low-cost non-quantitative test, but may provide useful information in low burden areas. We compared the prevalence of intestinal helminth infections assessed by the Kato-Katz and the Lumbreras rapid sedimentation test on 3 stool specimens from each of 1083 children. The sensitivities were compared using the McNemar paired test. Using the combined outcome of the 3 different stool tests as the standard, Kato-Katz had lower sensitivity than Lumbreras rapid sedimentation tests for Ascaris lumbricoides (85.1% vs. 95.1%, p = 0.03), Hymenolepis nana (77.7% vs. 97.9%, p < 0.01), Trichuris trichura (41.7% vs. 100%, p = 0.01), hookworm (0% vs. 100%, p = 0.01), and Strongyloides stercoralis (0% vs. 88%, p < 0.01). Kato-Katz demonstrated significantly lower sensitivity, missing most T. trichiura, hookworm, and S. stercoralis infections. The combination of Kato-Katz and Lumbreras rapid sedimentation tests enables the detection of more intestinal helminths infections in post-deworming low prevalence areas.

[Traditional treatments in an endemic area of american cutaneous Leishmaniasis in Peru]

In order to know the first-choice treatment by villagers of an endemic area of Cutaneous Leishmaniasis (CL) prior to medical attention in a health care center, a cross sectional study was realized in Pichupampa town. A census was made in order to collect demographic data and previous history of CL. 254 participants were surveyed. 41.7% (106/254) of the village had CL at least once in their lives and only half of them went to a health center to seek for primary care. 76/106 (71.7%) used some traditional treatment as their first choice and only 23.6% (25/106) subjects went to a health-care center without manipulation of their lesions. It's evident that a high percentage (71.7%) of people potentially infected by CL manipulate and treat their lesions with traditional treatments prior to professional health-care, actions that could interfere with the diagnosis and effectiveness of the program implemented by the Health Ministry.