Comparison of culture-dependent and -independent bacterial detection results on nasal swabs in dogs with nasal discharge

OBJECTIVES

The role of bacterial communities in the pathophysiology of canine nasal disease is still unclear. How and when to treat dogs with suspected secondary bacterial rhinitis and on which test to rely before making a decision to treat with antimicrobials has not been established. The objective is to compare the results of bacterial identification using agar-plate cultures and 16S rRNA gene amplicon sequencing in dogs with nasal discharge suspected to be of bacterial origin.

MATERIALS AND METHODS

Twenty-nine client-owned dogs presented for investigation of nasal disease were included in the study. Paired swabs were collected from the same affected nasal cavity. One swab was streaked on 4 agar media (Columbia Blood Agar, MacConkey, Chapman and Edward's). The other swab was stored in a sterile cryotube at -80°. Extracted DNA underwent a polymerase chain reaction targeting the V1-V3 region of the 16S rRNA gene.

RESULTS

At least one of the species detected by amplicon sequencing with a relative abundance of >10% was also identified by culture in 14 cases (48.3%), in association with marked predominance of one taxon (>80% relative abundance) in six of 14 cases. In 12 dogs (41.4%), the cultured isolates were rare or undetected components of the corresponding sequence libraries. A negative culture in the face of bacterial predominance (>50% relative abundance) of a potentially pathogenic bacteria detected by sequencing occurred in 17% (n=5) of cases; however, the use of other agar media may have decreased this percentage.

CLINICAL SIGNIFICANCE

Standard culture does not reliably predict the bacterial profile detected by 16S rRNA gene amplicon sequencing.

Central Retinal Artery Occlusion in Rhino-Orbital-Cerebral Mucormycosis: An Inflammatory-Prothrombotic State

PURPOSE

The aim was to evaluate patient profiles of rhino-orbital-cerebral mucormycosis (ROCM) cases with central retinal artery occlusion (CRAO) postcoronavirus disease 2019.

DESIGN

A nonrandomized retrospective case-control study.

METHODS

The ROCM cases presenting with CRAO were compared with a control ROCM group without CRAO at a tertiary care center. Demography, systemic status, clinical features, histopathology, imaging, and blood profile were assessed for any specific risk factors.

RESULTS

A total of 12 patients were seen in the CRAO group and 16 in the non-CRAO group. The male-to-female ratio was 3:1 with a mean age of 49.5 years. In the CRAO group, 75% had diabetes mellitus with mean hemoglobin A1c of 9.03%, and 66.7% had received steroid treatment. All cases were histopathologically confirmed positive for mucor. There was a significant difference in mean D-dimer and serum ferritin between the 2 groups, with higher level in the CRAO group. All patients with CRAO had light perception-negative vision, with total ophthalmoplegia and proptosis seen in 66.7% of cases. Four patients had orbital apex involvement, 5 had cavernous sinus involvement, and 8 had intracranial involvement in the CRAO group.

CONCLUSIONS

Inflammatory markers D-dimer and serum ferritin were significantly associated with CRAO, suggestive of hyperinflammatory and hypercoagulable state. A high index of suspicion should be maintained in cases with elevated markers and prophylactic anticoagulants can be started to prevent CRAO in a subset of patients.

Efficacy of mupirocin, neomycin and octenidine for nasal Staphylococcus aureus decolonisation: a retrospective cohort study

BACKGROUND

Periprosthetic joint infection (PJI) causes significant morbidity. Methicillin sensitive Staphylococcus aureus (MSSA) is the most frequent organism, and the majority are endogenous. Decolonisation reduces PJIs but there is a paucity of evidence comparing treatments. Aims; compare 3 nasal decolonisation treatments at (1) achieving MSSA decolonisation, (2) preventing PJI.

METHODS

Our hospital prospectively collected data on our MSSA decolonisation programme since 2013, including; all MSSA carriers, treatment received, MSSA status at time of surgery and all PJIs. Prior to 2017 MSSA carriers received nasal mupirocin or neomycin, from August 2017 until August 2019 nasal octenidine was used.

RESULTS

During the study period 15,958 primary hip and knee replacements were performed. 3200 (20.1%) were MSSA positive at preoperative screening and received decolonisation treatment, 698 mupirocin, 1210 neomycin and 1221 octenidine. Mupirocin (89.1%) and neomycin (90.9%) were more effective at decolonisation than octenidine (50.0%, P < 0.0001). There was no difference in PJI rates (P = 0.452).

CONCLUSIONS

Mupirocin and neomycin are more effective than octenidine at MSSA decolonisation. There was poor correlation between the MSSA status after treatment (on day of surgery) and PJI rates. Further research is needed to compare alternative MSSA decolonisation treatments.

Black Fungus Complicated with COVID-19 in a Man with Underlying Non-Hodgkin's Lymphoma

COVID-19 is a disease reported to suppress cellular immunity. This may lead to the development of opportunistic infections, among others black fungus, or mucormycosis. On the other hand, pre-existing defect in immunity may render patients susceptible to both mucormycosis and COVID-19. Mucormycosis is a relatively rare fungal infection with rapid progression unless diagnosed promptly and treated adequately, and urgent surgical and medical intervention is lifesaving. The manifestation of mucormycosis largely depends on the presence of exposure to the pathogen and the existing risk factor of the host. As black fungus is locally invasive, the majority of cases will involve tissue damage with local destruction and contiguous spread to nearby structure. We here with present a case of black fungus complicated with COVID-19 in a man with underlying non-Hodgkin's lymphoma.

Acute Invasive Rhino-Orbital Mucormycosis in a Patient With COVID-19-Associated Acute Respiratory Distress Syndrome

Acute invasive fungal rhinosinusitis is a rare, although highly morbid, infection primarily affecting immunosuppressed individuals. The same population is at particularly high risk of complications and mortality in the setting of SARS-CoV-2 infection and coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome. The authors present a case of acute invasive fungal rhino-orbital mucormycosis in a patient with COVID-19 and discuss the prevalence, diagnosis, and treatment of fungal coinfections in COVID-19. Prompt recognition, initiation of therapy, and consideration of the challenges of rapidly evolving COVID-19 therapy guidelines are important for improving patient survival.

Interferon inducible GBPs restrict Burkholderia thailandensis motility induced cell-cell fusion

Innate immunity responds to pathogens by producing alarm signals and activating pathways that make host cells inhospitable for pathogen replication. The intracellular bacterium Burkholderia thailandensis invades the cytosol, hijacks host actin, and induces cell fusion to spread to adjacent cells, forming multinucleated giant cells (MNGCs) which promote bacterial replication. We show that type I interferon (IFN) restricts macrophage MNGC formation during B. thailandensis infection. Guanylate-binding proteins (GBPs) expressed downstream of type I IFN were required to restrict MNGC formation through inhibition of bacterial Arp2/3-dependent actin motility during infection. GTPase activity and the CAAX prenylation domain were required for GBP2 recruitment to B. thailandensis, which restricted bacterial actin polymerization required for MNGC formation. Consistent with the effects in in vitro macrophages, Gbp2-/-, Gbp5-/-, GbpChr3-KO mice were more susceptible to intranasal infection with B. thailandensis than wildtype mice. Our findings reveal that IFN and GBPs play a critical role in restricting cell-cell fusion and bacteria-induced pathology during infection.

Mucormycosis creeping along the nerves in an immunocompetent individual

Mucormycosis is a rare opportunistic fungal infection, often life-threatening. We report an unusual case of rhinocerebral mucormycosis in an immunocompetent patient. A 23-year-old male presented with headache, speech disturbance and hearing difficulty for 4 weeks. Magnetic resonance imaging (MRI) revealed right cerebellar abscess and enhancing soft tissue in the nasal cavity, extending to cranial and infratemporal fossae. Computed tomography (CT) revealed the widening of foramen rotundum and sclerosis involving the sphenoid and ethmoid sinuses. MR Spectroscopy revealed multiple peaks between 3.6 and 3.8 parts per million (ppm) which could represent trehalose. Nasal mucosa scrapings confirmed mucormycosis. Suspicion of a fungal infection needs to be considered even in the absence of immunocompromised status.

Orbitocerebral Mucormycosis in a Patient With Central Nervous System Lymphoma

A 61-year-old man with well-controlled diabetes mellitus type 2, cirrhosis from hepatitis C, alcohol abuse, and portal hypertension presented with painful vision loss and left orbital swelling. Imaging showed diffuse orbital, perineural, and pachymeningeal inflammation. He was initially diagnosed with neurosarcoidosis. However, cerebrospinal fluid analysis revealed central nervous system lymphoma, and lacrimal gland biopsy showed fungal organisms consistent with mucormycosis. The authors describe a case of Mucorales infection lacking sinonasal involvement and discuss the differential diagnosis and management of patients presenting with orbital and central nervous system inflammation from this uncommon fungal infection.

Sinonasal aspergillosis: Outcome after topical treatment in dogs with cribriform plate lysis

BACKGROUND

Cribriform lysis has been considered a contraindication for topical treatment of sinonasal aspergillosis (SNA) because of concerns about drug extravasation with resultant neurologic signs or death.

OBJECTIVE/HYPOTHESIS

To describe dogs with SNA and cribriform plate lysis treated with topical antifungal medications. Our hypothesis was that the conventional dogma that topical therapy should be avoided in these cases is incorrect.

ANIMALS

Nine client-owned dogs with SNA and lysis of the cribriform plate, lysis of the floor of a frontal sinus or both detected by computed tomography (CT).

METHODS

A retrospective review of medical records was performed. Dogs that met inclusion criteria (ie, SNA confirmed by at least 1 laboratory test, braincase affected on CT, and topical treatment applied) were included. Size of lesions, ancillary diagnostic test results, topical therapy, and adjuvant PO treatments were recorded. Outcome was determined by phone calls.

RESULTS

Four dogs were alive at the time of the manuscript submission with follow-up ranging from 188 to 684 days without neurological signs observed. All dogs were discharged without major complication 1-7 days postoperatively. One dog that had presented with a history of seizures experienced seizure activity 2 months after treatment.

CONCLUSIONS AND CLINICAL IMPORTANCE

Topical therapy did not result in complications in these dogs in which lytic regions as large as 16 × 22 mm2 were noted. Sinonasal aspergillosis associated lysis of the cribriform plate; lysis of the floor of a frontal sinus or both detected on CT is not necessarily a contraindication to topical therapy.

Resolution of esophageal dysmotility following treatment of nasal disease in a dog

A 2-year-old Rottweiler dog was evaluated for cough, regurgitation, and nasal discharge, and was subsequently diagnosed with sinonasal aspergillosis and secondary esophageal disease. Following treatment of sinonasal aspergillosis, all clinical signs resolved. To the authors' knowledge, this is the first report of resolution of esophageal dysfunction following treatment of sinonasal aspergillosis.

A fatal case of rhinocerebral mucormycosis of the jaw after dental extractions and review of literature

The purpose of presenting this case is to report a fatal case of rhinocerebral mucormycosis post-dental extraction in a patient with uncontrolled diabetes mellitus. Several cases of rhinocerebral mucormycosis have been reported, but mucocutaneous mucormycosis has not been commonly reported to be a part of polymicrobial wound infections at multifocal sites. To the best of author's knowledge, this is the second case of polymicrobial rhinocerebral infection involving mucormycosis.

Bacterial microbiome in the nose of healthy cats and in cats with nasal disease

Background

Traditionally, changes in the microbial population of the nose have been assessed using conventional culture techniques. Sequencing of bacterial 16S rRNA genes demonstrated that the human nose is inhabited by a rich and diverse bacterial microbiome that cannot be detected using culture-based methods. The goal of this study was to describe the nasal microbiome of healthy cats, cats with nasal neoplasia, and cats with feline upper respiratory tract disease (FURTD).

Methodology/Principal findings

DNA was extracted from nasal swabs of healthy cats (n = 28), cats with nasal neoplasia (n = 16), and cats with FURTD (n = 15), and 16S rRNA genes were sequenced. High species richness was observed in all samples. Rarefaction analysis revealed that healthy cats living indoors had greater species richness (observed species p = 0.042) and Shannon diversity (p = 0.003) compared with healthy cats living outdoors. Higher species richness (observed species p = 0.001) and Shannon diversity (p<0.001) were found in middle-aged cats in comparison to healthy cats in different age groups. Principal coordinate analysis revealed separate clustering based on similarities in bacterial molecular phylogenetic trees of 16S rRNA genes for indoor and outdoor cats. In all groups examined, the most abundant phyla identified were Proteobacteria, Firmicutes, and Bacteroidetes. At the genus level, 375 operational taxonomic units (OTUs) were identified. In healthy cats and cats with FURTD, Moraxella spp. was the most common genus, while it was unclassified Bradyrhizobiaceae in cats with nasal neoplasia. High individual variability was observed.

Conclusion

This study demonstrates that the nose of cats is inhabited by much more variable and diverse microbial communities than previously shown. Future research in this field might help to develop new diagnostic tools to easily identify nasal microbial changes, relate them to certain disease processes, and help clinicians in the decision process of antibiotic selection for individual patients.

Blastomycosis of the nose: A case report

Blastomyces dermatitidis is a thermally dimorphic fungus endemic to the North American soil near the Mississippi, Ohio, and St. Lawrence river valleys, as well as the Great Lakes Basin. It is responsible for blastomycosis, a systemic pyogranulomatous disease. Blastomycosis of the head and neck is decidedly uncommon and often mistaken for cancer. There are only 3 previous case reports of blastomycosis presenting as an intranasal lesion. We report the unusual case of a 24-year-old man with blastomycosis presenting with a 4-week history of a progressively enlarging intranasal mass who had complete resolution of symptoms after treatment with itraconazole and surgical excision of the lesion.

Outbreak of Methicillin-Resistant Staphylococcus aureus Colonization and Infection in a Neonatal Intensive Care Unit Epidemiologically Linked to a Healthcare Worker With Chronic Otitis

Objective.

To describe the investigation and interventions necessary to contain an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection in a neonatal intensive care unit (NICU).

Design.

Retrospective case finding that involved prospective performance of surveillance cultures for detection of MRSA and molecular typing of MRSA by repetitive-sequence polymerase chain reaction (rep-PCR).

Setting.

Level III NICU in a tertiary care center.

Participants.

Three neonates in a NICU were identified with MRSA bloodstream infection on April 16, 2004. A point prevalence survey identified 6 additional colonized neonates (attack rate, 75% [9 of 12 neonates]). The outbreak strain was phenotypically unusual.

Interventions.

Cohorting and mupirocin therapy were initiated for neonates who had acquired MRSA during the outbreak. Contact precautions were introduced in the NICU, and healthcare workers (HCWs) were retrained in cleaning and disinfection procedures and hand hygiene. Noncolonized neonates and newly admitted patients had surveillance cultures performed 3 times per week.

Results.

Two new colonized neonates were identified 1 month later. HCW X, who had worked in the NICU since June 2003, was identified as having chronic otitis. MRSA was isolated from cultures of swab specimens from HCW X's ear canal and nares. HCW X was epidemiologically linked to the outbreak. Molecular typing (by rep-PCR) confirmed that the isolates from HCW X and from the neonates were more than 90% similar. Retrospective review of NICU isolates revealed that the outbreak strain was initially cultured from a neonate 2 months after HCW X began working on the unit. The epidemic strain was eradicated after removing HCW X from patient care in the NICU.

Conclusion.

An outbreak of MRSA colonization and infection in a NICU was epidemiologically linked to a HCW with chronic otitis externa and nasal colonization with MRSA. Eradication was not achieved until removal of HCW X from the NICU. Routine surveillance for MRSA may have allowed earlier recognition of the outbreak and is now standard practice in our NICU.

Disseminated Mycobacterium marinum Infection With a Destructive Nasal Lesion Mimicking Extranodal NK/T Cell Lymphoma: A Case Report

Mycobacterium marinum is a ubiquitous waterborne organism that mainly causes skin infection in immunocompetent patients, and its disseminated infection is rare. Extranodal NK/T cell lymphoma, nasal type (ENKL) usually localizes at the nasal and/or paranasal area, but occasionally disseminates into the skin/soft tissue and gastrointestinal tract. Compromised immunity is a risk factor for developing nontuberculous mycobacterial (NTM) infection and malignant lymphoma, and the 2 diseases may share similar clinical presentation; however, only a few reports have described NTM infection mimicking malignant lymphoma.A 43-year-old Japanese man presented to our hospital complaining of multiple progressive skin nodules and purulent nasal discharge for 3 weeks. He was diagnosed with Crohn disease with refractory enteropathic arthritis and has been treated with anti-tumor necrosis factor alpha agents for 25 years. Fiberoptic nasal examination revealed septal perforation with hemorrhagic mucus and purulent rhinorrhea. Histological examination of the nasal septum revealed the infiltration of atypical medium-to-large-sized cells with erosion. The cells were positive for cytoplasmic CD3, granzyme B, and Epstein-Barr virus-encoded small RNA. Histological examination of the skin nodules and auricle also showed infiltration of atypical lymphocytes. The patient was tentatively diagnosed with ENKL, and chemotherapy was considered. However, the skin lesions decreased in size after discontinuation of immunosuppressive agents and minocycline administration. Two weeks later, nasal septum and lavage fluid and left leg skin cultures were positive for M marinum, and minocycline was discontinued. The skin and the nasal lesions improved after 2 months. To the best of our knowledge, this is the first case of disseminated M marinum infection with a destructive nasal lesion mimicking ENKL. The differentiation between M marinum infection and ENKL is clinically important because misdirected treatment leads to a poor prognosis. NTM infections including M marinum should be considered in differential diagnosis of ENKL. Bacterial cultures, pathological analysis, and close monitoring are required for the differentiation of ENKL and disseminated M marinum infection; both are serious diseases and early diagnostic distinction between them and immediate appropriate treatment will improve the patient's prognosis.

Conidiobolus coronatus granuloma of the right inferior turbinate: A rare presentation

Fungal infections are common in tropical countries such as India. Very few clinical cases caused by the Entomophthorales Zygomycetes have been reported. Rhinofacial infection is a rare form of zygomycosis in humans, and only limited information regarding optimal treatment is available. We report here a rare case of rhinofacial Conidiobolus coronatus infection in a previously healthy 18-year-old man who presented with a fungal granuloma of the right inferior turbinate and face. Diagnosis was confirmed by microbiologic culture from a tissue biopsy. The infection was successfully treated with surgery and itraconazole therapy for 12 months. The clinical presentation and treatment of this rare, chronic, indolent form of fungal infection are highlighted in this article.

Nasal vestibulitis due to targeted therapies in cancer patients

BACKGROUND AND PURPOSE

Cancer patients treated with targeted therapies (e.g., epidermal growth factor receptor inhibitors) are susceptible to dermatologic adverse events (AEs) including secondary skin infections. Whereas infections such as paronychia and cellulitis have been reported, nasal vestibulitis (NV) has not been described with the use of these agents. The aim of our study was to characterize NV in cancer patients treated with targeted therapies.

METHODS

We utilized a retrospective chart review of cancer patients who had been referred to dermatology and were diagnosed with NV. We recorded data including demographics, referral reason, underlying malignancy, targeted anticancer regimen, NV treatment, and nasal bacterial culture results.

RESULTS

One Hundred Fifteen patients were included in the analysis, of which 13 % experienced multiple NV episodes. Skin rash was the most common reason (90 %) for a dermatology referral. The most common underlying malignancies were lung (43 %), breast (19 %), and colorectal (10 %) cancer. Sixty-eight percent of patients had been treated with an EGFRI-based regimen. Nasal cultures were obtained in 60 % of episodes, of which 94 % were positive for one or more organisms. Staphylococcus aureus was the most commonly isolated organism [methicillin-sensitive S. aureus 43 %; methicillin-resistant S. aureus 3 %].

CONCLUSIONS

We report the incidence and characteristics of an unreported, yet frequent dermatologic condition in cancer patients treated with targeted therapies. These findings provide the basis for additional studies to describe the incidence, treatment, and consequences of this event. A better understanding of NV would mitigate its impact on patients' quality of life and risk for additional dermatologic AEs.