Normal Oral Flora Research Articles

GARLING WITH A SOLUTION OF ACACIA CARPA HONEY SOLUTION OF 10% CONCENTRATION ON THE DEGREE OF SALIVA ACIDITY AND THE TOTAL PLATE COUNT (TPC) OF THE NORMAL FLORA OF THE ORAL CAVITY IN CHILDREN

Saliva functions as a buffer that can prevent a decrease in pH or an increase in mouth acidity. Alcohol-free mouthwash containing herbs using honey solution which is made from natural ingredients and is safe for children can be used as an appropriate preventive measure to maintain oral hygiene. The normal flora of the oral cavity consists of microorganisms including bacteria, fungi, mycoplasma, protozoa and possibly viruses. The aim of the research was to analyze the effect of gargling with a 10% concentration of Acacia Carpa (Acacia Crassicarpa) honey solution on the degree of saliva acidity and Total Plate Count (TPC) of normal oral flora and Gram bacteria in children aged 8-9 years. Method: True experimental research type, with a group pre-test post-test with control group design. The sampling technique was carried out by simple random sampling of 30 children. The degree of acidity of saliva is measured using litmus paper, bacterial colonies are incubated on Nutrient Agar media for 24 hours and counted. Test the normality of the data using the one sample Kolmogorov-Smirnov test. Data were analyzed using the Paired T-test if it was normally distributed and the Kruskal Wallis test if it was not normally distributed. Results: The 10% concentration honey gargle group resulted in the average degree of acidity before, namely 7.00, after 6.98, then the average Total Plate Count (TPC) result for normal oral flora, namely before, was 100.47 CFU/ml, whereas after, it was 69.67. CFU/ml. Paired T-Test test results for the 10% honey gargle group Sig. 0.003 (< 0.05), so there is a significant difference between the Total Plate Count (TPC) before and after gargling honey with a concentration of 10%. Conclusion: There is an effect of gargling honey with a concentration of 10% on Total Plate Count of normal oral flora

Abstract We127: Infective Endocarditis in COVID-19 - An Unusual Suspect

Introduction: The COVID-19 pandemic globally overwhelmed healthcare systems and the complications associated with this illness have contributed to poor outcomes. The hypercoagulable state associated with COVID-19 is well recognized in the literature. Thromboembolic complications such as left ventricular thrombus (LVT), deep venous thrombosis (DVT) and pulmonary embolism (PE) have been increasingly reported. Dhakal et al. published an association between COVID-19 and cardiovascular disease, including possible complication by infective endocarditis (IE) which was confirmed by Amir et al. reporting the first case. Since then, there have been few reported cases. We present a case of COVID-19 in a patient who developed LVT, complicated by non-valvular IE by an underreported organism, Granulicatella adiacens. Case Presentation: A 55-year-old male with history of dental caries, provoked DVT/PE, NSTEMI x2 and STEMI in-stent restenosis requiring thrombectomy presented to the hospital with a 2-day history of shortness of breath, fatigue, cough, change in mentation and right-sided weakness. He tested positive for COVID-19 by NAAT. CXR revealed cardiomegaly and multiple bilateral infiltrates. CT head demonstrated acute ischemic stroke of the left occipital, parietal and posterior temporal lobes, also confirmed on MRI. CTA neck showed 30% stenosis of left ICA. Blood cultures x2 resulted positive for G. adiacens. Echocardiogram was obtained, demonstrating reduced EF of 35% and the presence of a large, 2.7 x 2.2cm mobile thrombus in the apical-septal region of the left ventricle, not visualized on previous echocardiogram 6 months earlier. Methods: Data was collected from direct patient care and electronic medical records. Discussion: G. adiacens is a fastidious gram-positive coccus, part of the nutritionally variant streptococci (NVS) species, and part of the normal oral and gastrointestinal flora. It is also found in dental plaques and endodontic abscesses. NVS account for less than 5% of cases of bacteremia and IE. G. adiacens account for even fewer cases. Two separate meta-analyses conducted by Quintero-Martinez et al. and George et al. failed to reveal any cases of IE attributable to G. adiacens in the setting of COVID-19 infection. In conclusion, we believe that the hypercoagulable state of COVID-19 infection led to endocardial damage and development of LVT, thereby creating a nidus for microorganism adherence from underlying dental carries resulting in thromboembolic stroke.

Contemporary Update on the Microbiology of Paranasal Sinusitis

Background: Sinusitis, whether acute or chronic, is likely due at least in part to disruptions in the microbiota of the paranasal sinuses. Sinus cultures are often employed to guide medical treatment. Objective: To quantify the contemporary microbiology of the paranasal sinuses and better understand the utility of paranasal sinus cultures. Methods: We identified patients from 2018 to 2019 with sinus cultures taken by an otolaryngologist in the outpatient setting in our healthcare system with a concurrent diagnosis of acute or chronic rhinosinusitis. These cultures were analyzed based on their culture type and result. The most commonly isolated bacteria were further analyzed by species; Staphylococcus resistance patterns were analyzed as well. Results: A total of 2302 culture samples were collected: 2012 (87%) bacterial, 287 (13%) fungal, and 3 (0.1%) mycobacterial cultures. The results of more than half (1142, 57%) of these bacterial cultures were positive for a named genus, while those of 592 (29%) were positive for normal sinus flora and 16 (0.8%) for normal oral flora, and those of 183 (9%) showed no growth. The results of another 79 (4%) bacterial cultures were positive for unnamed bacteria, which were not further classified (e.g., Gram-negative rods). Of the positive bacterial cultures with named genera, the most common genera identified was Staphylococcus (383, 34%). Of these, the most common species of Staphylococcus was S. aureus (311, 81%), 42 of which (14%) showed methicillin resistance (MRSA). Of the fungal cultures, 265 (92%) resulted in no growth, and all three mycobacterial cultures showed no growth. Conclusions: In contrast to fungal cultures, the majority (57%) of sinus bacterial cultures showed positive results, with the identification of a named genus, highlighting the potential utility of this assay in guiding medical therapy.

Antifungal Properties of Dracaena cinnabari Resin Extracts Against Candida albicans

Background: Candida albicans is the most prevalent fungal pathogen in humans, capable of causing a range of clinical infections from mucocutaneous conditions like oral thrush to life-threatening systemic diseases. While Candida species are typically part of the normal oral flora in about 75% of the global population, the rising resistance to antifungal drugs has become a significant concern. This highlights the urgent need to explore alternative antimicrobial agents, including natural phytochemicals derived from plants, as potential substitutes for synthetic chemicals to address the growing issue of antifungal resistance. Methods: This study aimed to evaluate the antifungal properties of Dracaena cinnabari resin extracts (methanol and water) against Candida albicans. The antifungal activity was assessed using the direct contact agar diffusion test, while the minimal inhibitory concentration (MIC) of the extracts was determined through the broth dilution method. Results: The antifungal susceptibility tests demonstrated that C. albicans was susceptible to both methanol and water extracts of D. cinnabari resin, with zones of inhibition measuring 32.2 ± 0.8 mm and 29.0 ± 1.1 mm, respectively. The MIC values ranged between 2.50 and 5.00 mg/mL for both extracts. Conclusion: The antifungal effectiveness of D. cinnabari resin extracts was comparable to that of the miconazole control, showing significant potential as a natural treatment option against Candida albicans. These findings suggest that Dracaena cinnabari resin could play a valuable role in the treatment and management of candidiasis, particularly oral candidiasis.

Candida albicans - relationship with prosthetic stomatitis

Introduction: The oral cavity is the permanent residence of various types of microorganisms that live in complex ecosystems,which are not yet sufficiently researched. The normal oral flora always undergoes changes, which depend on many factors:food, immunological factors, hygiene and all the changes that occur during life in the oral cavity. One of the most frequent reasons for these changes is the use of new materials in the mouth, whether they are tooth fillings or fixed or mobile prosthetic works. The spread of prosthetic stomatitis is a long-standing problem among wearers of mobile prostheses. Colonization by Candida spp is of particular clinical importance, in most patients who have encountered prosthetic stomatitis and the presence of Candida spp has been determined. the dominant species is Candida Albicans.Local factors can cause the transformation of Candida albicans from non-pathogenic to pathogenic microorganisms.

INFECTIOUS STOMATITIS IN CAPTIVE SALVATOR MERIANAE LIZARDS

Infectious stomatitis is a common ailment in captive reptiles, it arises from a combination of predisposing factors such as poor nutritional conditions, habitat issues or stress, where normal oral flora microorganisms act as pathogens, facilitating the disease development. This study aims to describe infectious stomatitis in a captive population of adult Salvator merianae lizards and to propose prophylactic measures for their maintenance in captivity. Within a population of 57 animals, a morbidity rate of 19.2% and a mortality rate of 7% were estimated. Microbiological analysis of oral mucosa revealed Pseudomonas aeruginosa susceptible to ceftazidime, ciprofloxacin, gentamicin, and amikacin. Symptoms ranged from asymptomatic to animals with mild oral cavity lesions or severe stomatitis, with some cases exhibiting respiratory complications. Histopathological examination of lung samples was consistent with caseous pneumonia. Intramuscular ceftazidime treatment and oral disinfection yielded excellent results for lizards with stomatitis, although a favorable response was not observed in animals with pneumonia.

An autopsy case of infective aortic aneurysm with Pasteurella multocida infection: clinicopathological appearance and a review of literatures

Here, we showed our clinicopathological findings of infected aortic aneurysm (IAA) with Pasteurella multocida, which is a Gram-negative coccobacillus and is part of the normal oral flora of many animals. The patient was a 76-year-old male animal owner with a history of diabetes mellitus, alcoholic liver damage, and laryngeal cancer. He died 16 days after admission without undergoing operation because of poor general condition. Autopsy showed saccular outpouching with loss of the existing aortic wall and marked neutrophilic infiltration in the suprarenal abdominal aorta. Rupture was not evident. A polymerase chain reaction assay using DNA extracted from formalin-fixed paraffin-embedded specimen of the aneurysmal wall detected the Pasteurella multocida gene, therefore we conclude that the present case was IAA of native aorta with Pasteurella multocida infection. A review of the literature showed that IAA of native aorta with Pasteurella multocida infection is opportunistic and that liver disorder, alcohol addiction, diabetes mellitus, and animal bite may increase its risk. On the other hand, aortic endograft infection with Pasteurella multocida frequently occurred without an immunocompromised state. Pasteurella multocida may be a distinct causative microorganism in IAA, and/or sepsis when the participant is an animal owner.

The effectiveness of spatholobus littoralis hassk ethanol extract against fungal growth of candida albicans

Candida albicans is a normal oral flora which has a virulence factor that is closely associated with Oral Candidiasis. Both bacteria have a symbiotic relationship in growth and production of biofilms. Spatholobus littoralis Hassk stem are often not known for their benefits so they are not utilized optimally and effectively. Spatholobus littoralis Hassk stem contains active ingredients in the form of tannins, alkaloids, triterpenoids, saponins, and flavonoids which are antifungal. Objectives: To determine the antifungal effects of ethanol extract bajakah tampala stem (Spatholobus littoralis Hassk) on C. albicans. Methods: In vitro laboratory experiment with post test only control group design. The test solutions used were ethanol extract of bajakah tampala stem (Spatholobus littoralis Hassk) 6.25%, 12.5%, 25%, 50% and 100%, nystatine as a positive control, and aquades 10% as a negative control. The antifungal test was carried out using the plate count method. Results: All concentrations of the extracts has a antifungal effect on C. albicans compared to the negative control (p<0,05). Conclusion: The ethanol extract of Spatholobus littoralis Hassk stem is effective in inhibiting the growth of the Candida albicans. Further studies on toxicity of Spatholobus littoralis Hassk stem ethanol extract on Candida albicans are necessary.

Pasteurella multocida Submandibular Gland Abscess and Sepsis: Case Report and Case Report

<em>Pasteurella multocida</em>, a gram-negative coccobacillus, part of the normal oral flora of many domestic and wild mammals, has been described a widespread veterinary pathogen and has the potential to cause zoonotic infections in humans resulting from injuries caused by household or wild pets.

Co-adaptation of Streptococcus mutans to simulated microgravity and silver nitrate

To sustain life on extended space missions, it is essential to maintain clean potable water. NASA currently uses iodine as the primary biocide in the potable water dispenser on the International Space Station and has recently proposed a potential switch to silver-based antimicrobials. Streptococcus mutans is the primary etiological agent of dental caries, part of the normal oral flora, and would endure direct exposure to water from the potable water dispenser. In our previous work, we examined the 100-day adaptive response of Streptococcus mutans to simulated microgravity (sMG). Here, we examined the evolutionary co-adaptation of S. mutans under sMG and silver nitrate (AgNO3) to evaluate the consequences of using silver as a primary biocide in space and the impact on the evolution of microbes from the oral microbiome. To do this, we adapted four populations of S. mutans under sMG and co-adapted four populations in simulated microgravity and silver nitrate using high-aspect ratio vessels for 100 days. Genomic analysis at multiple time points showed that S. mutans in sMG evolved variants consistent with our previous findings (SMU_1307c and SMU_399) while also acquiring novel mutations in the glutathione reductase gorA. The co-adapted populations showed mutations specific for the environment in ciaH/R, PBP1a, trkA, and trkB. We also assessed virulence phenotypes, and while simulated microgravity increased antibiotic susceptibility, sucrose-dependent adhesion, and, in some populations, acid tolerance, co-adaptation to silver nitrate reversed these effects. Overall, these data show that the use of silver as a biocide in simulated microgravity can evolve strains with novel genotypic and phenotypic traits that could alter virulence.

The First Case of Infectious Spondylitis Caused by Gemella bergeri

Gemella bergeri, a member of the genus Gemella, is a facultatively anaerobic, Gram-positive cocci. G. bergeri is a component of normal oral flora; however, it can become pathogenic and cause infections in patients with poor oral hygiene. A 78-year-old man was admitted to a hospital with a complaint of increasing posterior neck pain and lower back pain for 2 weeks. MRI was suggestive of infectious spondylitis at the C3-C4 level with prevertebral abscess formation, anterior epidural abscess formation. We identified Gemella bergeri in closed pus obtained during the surgery. Herein, we describe the first case of infective spondylitis caused by G. bergeri.

Dysphagia and Tongue Deviation: An Unexpected Cause.

Dysphagia and Tongue Deviation: An Unexpected Cause.

A RARELY REPORTED PNEUMONIA PATHOGEN: ROTHIA MUCILAGINOSA

A RARELY REPORTED PNEUMONIA PATHOGEN: ROTHIA MUCILAGINOSA

Prosthetic Joint Infection Due to Cardiobacterium hominis: Report of First Known Case and Review of C. hominis Septic Arthritis Literature

Introduction. The Cardiobacterium species is a pleomorphic Gram-negative bacterium discovered in 1964 and is part of the HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella) group of organisms known to cause endocarditis. It has low virulence and can also cause dacryocystitis, septicemia and abdominal abscess. We report a patient with C. hominis prosthetic joint infection in the absence of definitive endocarditis. Case Report. A 57-year-old man presented to his orthopedic surgeon 17 months after left total knee arthroplasty with a 4–5-day history of left knee pain following yard work. He had an aortic valve replacement in 2003, mitral valve repair in 2006 and bovine aortic valve replacement in 2019 (12 months previously). Aspirate of knee joint fluid was grossly cloudy. Two of two preoperative blood cultures revealed Cardiobacterium species after 4 days’ incubation. He was initially treated with intravenous vancomycin plus piperacillin/tazobactam followed by 6 weeks of parenteral ceftriaxone followed by five months of oral cefdinir. Patient is infection-free 6 months after completion of antimicrobial therapy. Discussion. Cardiobacterium hominis is a slow-growing, fastidious, capnophilic, Gram-negative bacillus commonly found in normal oral and upper respiratory flora. Google Scholar™ and PubMed®searches were conducted and this is the first reported case of prosthetic joint infection due to Cardiobacterium hominis. We found three previously reported cases of C. hominis pyogenic arthritis: one patient with native knee pyogenic arthritis, one patient with cervical spondylodiscitis and one patient with lumbar spondylodiscitis and epidural abscess. Two of these three patients had TEE-documented infective endocarditis and one had a bioprosthetic aortic valve without evident vegetation on TEE. Our patient had a bioprosthetic aortic valve without TEE evidence of endocarditis. C. hominis should be added to the list of organisms that can cause bacteremically spread prosthetic joint infection.

Effects of oral health intervention strategies on cognition and microbiota alterations in patients with mild Alzheimer's disease: A randomized controlled trial

We explored the effects of an oral health intervention on the oral microbiome and cognitive function of patients with mild Alzheimer's disease (AD) and determined the influence on disease progression. Sixty-six patients with mild AD were randomly assigned to intervention or control groups and received a 24-week oral health intervention and routine care, respectively. Data were collected at baseline and week 24. 16 S rRNA sequencing was used to analyze oral microbiota. After 24 weeks of oral health intervention, Kayser-Jones Brief Oral Health Status Examination (BOHSE), Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI), Nursing Home Adjustment Scale (NHAS), and Alzheimer's Disease Cooperative Study-ADL (ADCS-ADL) scores were different between groups (p < 0.05). Subgingival plaque in patients with AD showed significant differences in the diversity and abundance of oral microbiomes, with a higher abundance of normal oral flora in the intervention group. We found oral health intervention strategies are effective in modifying subgingival microbiota differences and slowing cognitive decline in mild AD patients.

Leptotrichia species Bacteremia in Hematological Malignancies

Here we present four clinical cases of immunocompromised patients experiencing bacteremia caused by Leptotrichia species in a few months with no common epidemiological link. Leptotrichia species are thin anaerobic gram-negative rods that inhabit multiple areas in the human body, including the oral microbiota. Many infections with Leptotrichia species occur in immunocompromised individuals classifying Leptotrichia species as opportunistic pathogens. Utilization of standard microbial identification methods of matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) initially yielded the same identification for all four Leptotrichia isolates as Leptotrichia buccalis. However, 16S ribosomal RNA sequencing confirmed the identification of only one of the four isolates as L. buccalis, while two of the four isolates were identified as Leptotrichia trevisanii. These four cases highlight the clinical importance of considering opportunistic infection in immunocompromised patients with unusual organisms considered members of the normal oral flora. J Microbiol Infect Dis 2022; 12(3):130-135.

Immunoglobulin Disorders and the Oral Cavity: A Narrative Review.

The oral mucosa is a mechanical barrier against the penetration and colonization of microorganisms. Oral homeostasis is maintained by congenital and adaptive systems in conjunction with normal oral flora and an intact oral mucosa. Components contributing to the defense of the oral cavity include the salivary glands, innate antimicrobial proteins of saliva, plasma proteins, circulating white blood cells, keratinocyte products of the oral mucosa, and gingival crevicular fluid. General disturbances in the level of immunoglobulins in the human body may be manifested as pathological lesions in the oral mucosa. Symptoms of immunoglobulin-related general diseases such as mucous membrane pemphigoid (MMP), pemphigus vulgaris (PV), linear IgA bullous dermatosis (LABD), Epidermolysis Bullosa Aquisita (EBA), and Hyper-IgE syndrome (HIES) may appear in the oral cavity. In this review, authors present selected diseases associated with immunoglobulins in which the lesions appear in the oral cavity. Early detection and treatment of autoimmune diseases, sometimes showing a severe evolution (e.g., PV), allow the control of their dissemination and involvement of skin or other body organs. Immunoglobulin disorders with oral manifestations are not common, but knowledge, differentiation and diagnosis are essential for proper treatment.

Prevalence of antibiotic resistance genes in the oral cavity and mobile genetic elements that disseminate antimicrobial resistance: A systematic review.

The objective of this review was to assess the prevalence of antibiotic resistance genes in the oral cavity and identify mobile genetic elements (MGEs) important in disseminating them. Additionally, to assess if age, geographic location, oral site, bacterial strains and oral disease influence the prevalence of these genes. Three electronic databases (Medline, Embase and the Cochrane Library) were used to search the literature. Journals and the grey literature were also hand searched. English language studies from January 2000 to November 2020 were selected. Primary screening was performed on the titles and abstracts of 1509 articles generated. One hundred and forty-seven full texts were obtained to conduct the second screening with strict inclusion and exclusion criteria. Forty-four final articles agreed with the inclusion criteria. Half of the studies were classed as low quality. tet(M) was the most prevalent gene overall and the conjugative transposon Tn916 the most common MGE associated with antibiotic resistance genes in the oral cavity. In babies delivered vaginally, tet(M) was more prevalent, whilst tet(Q) was more prevalent in those delivered by C-section. Generally, countries with higher consumption of antibiotics had higher numbers of antibiotic resistance genes. Agricultural as well as medical use of antibiotics in a country should always be considered. Between healthy, periodontitis and peri-implantitis subjects, there was no difference in the prevalence of tet(M); however, erm(B), tet(M) and tet(O) were higher in carious active children than the non-carious group. Subjects with poor oral hygiene have more pathogenic bacteria that carry resistance genes compared to those with good oral hygiene. Enterococcus faecalis isolates demonstrated significant tetracycline resistance (tet(M) up to 60% prevalence in samples) and erythromycin resistance (erm(B) up to 61.9% prevalence in samples), periodontal pathogens showed significant beta-lactam resistance with blaZ and cfxA present in up to 90%-97% of samples and the normal oral flora had a high level of erythromycin resistance with mef(A/E) present in 65% of Streptococcus salivarius isolates. The most common resistance gene was tet(M) in root canals, cfxA in subgingival plaque, erm(B) in supragingival plaque and tet(W) in 100% of whole saliva samples. The review highlights that although many studies in this area have been performed, 50% were classed as low quality. We advise the following recommendations to allow firm conclusions to be drawn from future work: the use of large sample sizes, investigate a broad range of antibiotic resistance genes, improved methodologies and reporting to improve the quality of genetic testing in microbiology and randomisation of subject selection.

Armed to the Teeth-The Oral Mucosa Immunity System and Microbiota.

The oral cavity is inhabited by a wide spectrum of microbial species, and their colonization is mostly based on commensalism. These microbes are part of the normal oral flora, but there are also opportunistic species that can cause oral and systemic diseases. Although there is a strong exposure to various microorganisms, the oral mucosa reduces the colonization of microorganisms with high rotation and secretion of various types of cytokines and antimicrobial proteins such as defensins. In some circumstances, the imbalance between normal oral flora and pathogenic flora may lead to a change in the ratio of commensalism to parasitism. Healthy oral mucosa has many important functions. Thanks to its integrity, it is impermeable to most microorganisms and constitutes a mechanical barrier against their penetration into tissues. Our study aims to present the role and composition of the oral cavity microbiota as well as defense mechanisms within the oral mucosa which allow for maintaining a balance between such numerous species of microorganisms. We highlight the specific aspects of the oral mucosa protecting barrier and discuss up-to-date information on the immune cell system that ensures microbiota balance. This study presents the latest data on specific tissue stimuli in the regulation of the immune system with particular emphasis on the resistance of the gingival barrier. Despite advances in understanding the mechanisms regulating the balance on the microorganism/host axis, more research is still needed on how the combination of these diverse signals is involved in the regulation of immunity at the oral mucosa barrier.

Bacterial and fungal growth in sputum cultures from 165 COVID-19 pneumonia patients requiring intubation: evidence for antimicrobial resistance development and analysis of risk factors

BackgroundCoronavirus SARS-CoV-2 causes COVID-19 illness which can progress to severe pneumonia. Empiric antibacterials are often employed though frequency of bacterial coinfection superinfection is debated and concerns raised about selection of bacterial antimicrobial resistance. We evaluated sputum bacterial and fungal growth from 165 intubated COVID-19 pneumonia patients. Objectives were to determine frequency of culture positivity, risk factors for and outcomes of positive cultures, and timing of antimicrobial resistance development.MethodsRetrospective reviews were conducted of COVID-19 pneumonia patients requiring intubation admitted to a 1058-bed four community hospital system on the east coast United States, March 1 to May 1, 2020. Length of stay (LOS) was expressed as mean (standard deviation); 95% confidence interval (95% CI) was computed for overall mortality rate using the exact binomial method, and overall mortality was compared across each level of a potential risk factor using a Chi-Square Test of Independence. All tests were two-sided, and significance level was set to 0.05.ResultsAverage patient age was 68.7 years and LOS 19.9 days. Eighty-three patients (50.3% of total) originated from home, 10 from group homes (6.1% of total), and 72 from nursing facilities (43.6% of total). Mortality was 62.4%, highest for nursing home residents (80.6%). Findings from 253 sputum cultures overall did not suggest acute bacterial or fungal infection in 73 (45%) of 165 individuals sampled within 24 h of intubation. Cultures ≥ 1 week following intubation did grow potential pathogens in 72 (64.9%) of 111 cases with 70.8% consistent with late pneumonia and 29.2% suggesting colonization. Twelve (10.8% of total) of these late post-intubation cultures revealed worsened antimicrobial resistance predominantly in Pseudomonas, Enterobacter, or Staphylococcus aureus.ConclusionsIn severe COVID-19 pneumonia, a radiographic ground glass interstitial pattern and lack of purulent sputum prior to/around the time of intubation correlated with no culture growth or recovery of normal oral flora ± yeast. Discontinuation of empiric antibacterials should be considered in these patients aided by other clinical findings, history of prior antimicrobials, laboratory testing, and overall clinical course. Continuing longterm hospitalisation and antibiotics are associated with sputum cultures reflective of hospital-acquired microbes and increasing antimicrobial resistance.Trial registration: Not applicable as this was a retrospective chart review study without interventional arm.