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AbstractBackgroundMethodsResultsConclusionUrinary tract infections (UTIs) are prevalent among patients carrying indwelling catheters in the intensive care unit (ICU). This study investigates antibiotic use and bacterial colonisation among ICU patients during the third wave of the COVID-19 pandemic, building on our prior discovery of increased Enterococcus colonisation associated with increased cephalosporin use in early COVID-19.Longitudinal urine samples from COVID-19 patients (n = 109) with transurethral catheterisation were analysed for bacterial prevalence, further identified via MALDI-TOF. Microbiological results were combined with clinical data obtained daily, assessed and compared with COVID-19 waves 1 and 2.Patients in wave 3 exhibited improved outcomes compared to those in waves 1 and 2, alongside a decrease in antibiotic use. Staphylococcus emerged as the primary bacterium and early colonizer of the urinary tract, potentially due to the absence of antibiotic treatment. Our results imply that length of stay (LOS) correlates solely with enteric pathogens and that antibiotic treatment correlates with colonisation by certain uropathogens, whereas the absence of antimicrobial therapy is associated with rapid colonisation of skin flora. Polymicrobial colonisation was common, predominantly involving Gram-positive bacteria.Our findings underscore the complexity of bacteriuria in ICU patients, advocating for targeted surveillance and tailored antibiotic approaches to mitigate UTI risk. Insights into antibiotic use and bacterial colonisation are vital for optimising stewardship practices, combating antimicrobial resistance, and enhancing ICU patient outcomes. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Cervicofacial necrotizing fasciitis (CNF) can occur as a dental complication in young, healthy individuals. Early diagnosis, treatment, and awareness of severe acute cervicofacial pain, rapid swelling, and radiological gas formation are crucial. Broad molecular profiling is recommended for understanding the organisms involved in such infections in future research. [ABSTRACT FROM AUTHOR]

Infected fracture nonunions often require prolonged treatment and recovery courses. It is unclear whether the bacterial microbiome influences the time to healing as well as the eradication of infection. The goals of this study are (1) to assess the bacterial microbiome affecting infected nonunions and (2) to evaluate the effects of bacterial speciation on associated outcomes. Between 2006 and 2022, data from 551 adult patients from a single academic institution who presented with a fracture nonunion were analyzed retrospectively for infection. All patients underwent revision surgery with three sets of cultures obtained intra-operatively. Patients with significant intra-operative cultures were grouped into gram-positive and gram-negative culture cohorts. These patients were managed with a standardized protocol involving surgical debridement, nonunion site fixation, and culture-directed antibiotic treatment. Primary outcome was time to fracture union. Secondary outcomes included number of re-operations and eventual amputation or reconstructive surgery. 56 nonunion patients (10 %) were diagnosed with an infected nonunion (44 g-positive, 12 g-negative). Of these, 3 g-positive patients received an amputation or arthroplasty procedure prior to fracture union, and seven were lost to follow-up. There were no significant differences in age, gender, or nonunion site between cohorts. Most nonunions occurred in the lower extremity. The most common bacteria were staph species (54.3 %). 36 g-positive and 10 g-negative patients achieved fracture union. Time to union was on average 158.4 days longer in the gram-negative cohort—but did not reach statistical significance (446.8 days gram-positive, 662.3 days gram-negative, p = 0.69). There was no difference in re-operation rates (1.9 % gram-positive, 2.2 % gram-negative, p = 0.84). Patients with infected nonunions had wide-ranging bacterial contamination that were treated successfully using a standardized protocol. However, patients with any gram-negative culture trended toward a delay in time to union. [ABSTRACT FROM AUTHOR]

PurposeInfectious keratitis is a serious cause of visual impairment, particularly in low-income communities. This study examines the associations between social risk factors and polymicrobial keratitis, multidrug resistance, pathogen spectrum, and outcomes at a county hospital.MethodsWe performed a retrospective study of Zuckerberg San Francisco General Hospital patients treated for infectious keratitis from 2010-2021. Multivariable regression was performed to analyze the relationships between social, medical, and psychiatric risk factors with polymicrobial growth, multidrug resistance, and clinical outcomes.ResultsOf 174 patients with infectious keratitis, 44 (25%) had polymicrobial growth. Six patients (14%) with polymicrobial growth had multidrug-resistant organisms. Homeless patients were more likely to present with polymicrobial infection (OR 3.4, p = 0.023), and polymicrobial infections were associated with multidrug-resistant organisms (p = 0.018). Smoking, drug use, HIV positivity, prior corneal pathology, and contact lens use were not associated with an increased risk of polymicrobial infection. Eleven patients (6.3%) were started on topical antibiotics prior to presentation; of these, none developed polymicrobial infections or multidrug-resistant organisms. Polymicrobial infections increased the likelihood to initiation of fortified antibiotics (OR 2.9, p = 0.011) but did not impact ulcer size, final visual acuity, time to resolution, or likelihood of emergent procedures.ConclusionsHomelessness correlates with an increased risk of polymicrobial keratitis and subsequent multidrug resistance, supporting initiation of broad antibiotic coverage in this population. Prior topical antibiotics did not increase risk of polymicrobial infection. Polymicrobial infection did not significantly worsen clinical outcomes.

In this study, we aimed to analyze the temporal distribution of polymicrobial periprosthetic joint infections (PJIs), while also evaluating the patient risk factors associated with these infections following total joint arthroplasty at our institution across 2 distinct periods. This retrospective cross-sectional study evaluated 259 patients who had knee or hip PJI from 2001 to 2006 and 2018 to 2022. A PJI was diagnosed using the 2018 International Consensus Meeting criteria. We utilized the Polymicrobial Pathogens' Co-occurrence Network Analysis, a novel approach that leverages network theory to map and quantify the complex interplay of organisms in PJIs. Of the 259 patients who had polymicrobial PJI, 58.7% were men, with mean age 67 years (range, 24 to 90). Of the 579 identified pathogens, Staphylococcus epidermidis was the most common (22.1%), followed by Staphylococcus aureus (9.0%) and Cutibacterium acnes (7.8%). The co-occurrence analysis indicated that Staphylococcus epidermidis frequently coexisted with Cutibacterium acnes (26 cultures) and Staphylococcus capitis (22 cultures). A notable increase in body mass index from 27.7 ± 4.4 in 2001 to 2006 to 29.7 ± 6.2 in 2018 to 2022 was observed (P =.001). Moreover, infections from Staphylococcus epidermidis , Cutibacterium acnes , and Staphylococcus capitis saw a significant uptick (P <.001). The study shows that from 2001 to 2022, there was a significant change in the pathogens responsible for polymicrobial PJIs, particularly an increase in Staphylococcus epidermidis , Cutibacterium acnes , and Staphylococcus capitis. Alongside these microbial changes, there was a rise in body mass index and shifts in comorbid conditions, such as more renal disease and fewer cases of congestive heart failure. These changes highlight the dynamic interplay between host and microbial factors in the pathogenesis of polymicrobial PJIs, necessitating adaptive strategies in both surgical and postoperative care to mitigate the rising tide of these complex infections. [ABSTRACT FROM AUTHOR]

Polymicrobial endocarditis is uncommon, and polymicrobial endocarditis in combination with Coxiella burnetii is very rare. We herein describe an extremely rare case of polymicrobial bivalvular endocarditis due to coinfection with Enterococcus faecalis and Coxiella burnetii in a 62-year-old male patient, and extensively review the relevant medical literature. To the best of our knowledge, only three similar cases have been previously reported. Q fever is a worldwide endemic bacterial zoonosis, but it and its most common chronic complication, endocarditis, are still underestimated and underdiagnosed worldwide. This situation reflects the paucity of reported cases of polymicrobial endocarditis in combination with Coxiella burnetii. Clinical presentation of Q fever endocarditis is highly nonspecific, and diagnosis may be delayed or missed, leading to severe and potentially fatal disease. Our case and the previously reported similar cases emphasize the need for further evaluation of infective endocarditis due to Coxiella burnetii, in all cases of culture-negative endocarditis, and in prolonged oligo-symptomatic inflammatory syndrome, particularly in the presence of valvular heart disease. This approach should be applied even when typical pathogens are isolated, especially in endemic areas of Q fever, and with atypical presentation. [ABSTRACT FROM AUTHOR]

Candida species comprise a ubiquitous pathogenic fungal genus responsible for causing candidiasis. They are one of the primary causatives of several mucosal and systemic infections in humans and can survive in various environments. In this study, we investigated the antifungal, anti-biofilm, and anti-hyphal effects of six Nsubstituted phthalimides against three Candida species. Of the derivatives, Nbutylphthalimide (NBP) was the most potent, with a minimum inhibitory concentration (MIC) of 100 µg/ml and which dose-dependently inhibited biofilm at sub-inhibitory concentrations (10-50 µg/ml) in both the fluconazole-resistant and fluconazole-sensitive Candida albicans and Candida parapsilosis.NBP also effectively inhibited biofilm formation in other pathogens including uropathogenic Escherichia coli, Staphylococcus epidermidis, Staphylococcus aureus, and Vibrio parahaemolyticus, along with the polymicrobial biofilms of S. epidermidis and C. albicans. NBP markedly inhibited the hyphal formation and cell aggregation of C. albicans and altered its colony morphology in a dose-dependent manner. Gene expression analysis showed that NBP significantly downregulated the expression of important hyphal- and biofilm-associated genes, i.e., ECE1, HWP1, and UME6, upon treatment.NBPalso exhibited mild toxicity at concentrations ranging from 2 to 20 µg/ml in a nematodemodel. Therefore, this study suggests that NBP has anti-biofilm and antifungal potential against various Candida strains. [ABSTRACT FROM AUTHOR]

ABSTRACT Chelsey VanDrisse works in the field of microbial physiology, studying how acylation of small molecules and proteins affects the development of Pseudomonas biofilms. In this mSphere of Influence article, she reflects on the paper “Community composition shapes microbial-specific phenotypes in a cystic fibrosis polymicrobial model system” by Jean-Pierre et al. This paper prompted her to reassess her approach to studying antibiotic tolerance and her design of experiments that search for disease-relevant mutants and phenotypes in the laboratory.

Key Clinical Message Cervicofacial necrotizing fasciitis (CNF) can occur as a dental complication in young, healthy individuals. Early diagnosis, treatment, and awareness of severe acute cervicofacial pain, rapid swelling, and radiological gas formation are crucial. Broad molecular profiling is recommended for understanding the organisms involved in such infections in future research.

ABSTRACT Chronic polymicrobial infections involving Pseudomonas aeruginosa and Staphylococcus aureus are prevalent, difficult to eradicate, and associated with poor health outcomes. Therefore, understanding interactions between these pathogens is important to inform improved treatment development. We previously demonstrated that P. aeruginosa is attracted to S. aureus using type IV pili (TFP)-mediated chemotaxis, but the impact of attraction on S. aureus growth and physiology remained unknown. Using live single-cell confocal imaging to visualize microcolony structure, spatial organization, and survival of S. aureus during coculture, we found that interspecies chemotaxis provides P. aeruginosa a competitive advantage by promoting invasion into and disruption of S. aureus microcolonies. This behavior renders S. aureus susceptible to P. aeruginosa antimicrobials. Conversely, in the absence of TFP motility, P. aeruginosa cells exhibit reduced invasion of S. aureus colonies. Instead, P. aeruginosa builds a cellular barrier adjacent to S. aureus and secretes diffusible, bacteriostatic antimicrobials like 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) into the S. aureus colonies. Reduced invasion leads to the formation of denser and thicker S. aureus colonies with increased HQNO-mediated lactic acid fermentation, a physiological change that could complicate treatment strategies. Finally, we show that P. aeruginosa motility modifications of spatial structure enhance competition against S. aureus. Overall, these studies expand our understanding of how P. aeruginosa TFP-mediated interspecies chemotaxis facilitates polymicrobial interactions, highlighting the importance of spatial positioning in mixed-species communities.IMPORTANCEThe polymicrobial nature of many chronic infections makes their eradication challenging. Particularly, coisolation of Pseudomonas aeruginosa and Staphylococcus aureus from airways of people with cystic fibrosis and chronic wound infections is common and associated with severe clinical outcomes. The complex interplay between these pathogens is not fully understood, highlighting the need for continued research to improve management of chronic infections. Our study unveils that P. aeruginosa is attracted to S. aureus, invades into neighboring colonies, and secretes anti-staphylococcal factors into the interior of the colony. Upon inhibition of P. aeruginosa motility and thus invasion, S. aureus colony architecture changes dramatically, whereby S. aureus is protected from P. aeruginosa antagonism and responds through physiological alterations that may further hamper treatment. These studies reinforce accumulating evidence that spatial structuring can dictate community resilience and reveal that motility and chemotaxis are critical drivers of interspecies competition.

The interactions between pathogens during infection and the impact of these interactions on drug effectiveness are poorly understood, making polymicrobial infections challenging to treat. During an infection, cross-interactions between bacteria and fungi can strengthen virulence mechanisms and affect how the disease develops. The purpose of this study is to determine how Pseudomonas aeruginosa interacts with Candida glabrata, Candida albicans, Candida krusei, Candida parapsilosis, and Candida tropicalis in the development of polymicrobial biofilms. Pseudomonas aeruginosa, Candida albicans, Candida krusei, Candida parapsilosis, Candida glabrata, and Candida tropicalis isolates were used in this experimental investigation. After preparing a 0.5 Mc Farland suspension of each isolate, the gold standard for measuring biofilm was applied: the Tissue Plate Culture (TCP) method. After that, an ELISA reader with a wavelength of 595 nm was used to measure the optical density (OD) of the biofilm. SPSS 26.0 was then used for statistical analysis to compare the OD values between Pseudomonas aeruginosa that had not been exposed to Candida and those that had. Pseudomonas aeruginosa and Candida are found to interact synergistically if there is an increase in OD, and antagonistic interaction is discovered if there is a decrease in OD. In comparison to the group that was not exposed to Candida, Pseudomonas aeruginosa exposed to Candida albicans, Candida krusei, Candida parapsilosis, Candida glabrata, and Candida tropicalis showed an increase in the OD value of biofilm. Pseudomonas aeruginosa and Candida albicans, Candida glabrata, Candida krusei, Candida parapsilosis, and Candida tropicalis interact synergistically.

Background: The prevalence of fungal bloodstream infections (BSI), especially candidaemia, has been increasing globally during the last decades. Fungal diagnosis is still challenging due to the slow growth of fungal microorganisms and need for special expertise. Fungal polymicrobial infections further complicate the diagnosis and extend the time required. Epidemiological data are vital to generate effective empirical treatment strategies. Objectives: The overall aim of this project is to describe the epidemiology of monomicrobial candidaemia and polymicrobial BSI, both with mixed fungaemia and with mixed Candida/bacterial BSIs. Methods: We conducted a single‐centre retrospective epidemiological study that encompasses 950,161 blood cultures during the years 2010 to 2020. The epidemiology of monomicrobial and polymicrobial candidaemia episodes were investigated from the electronic records. Results: We found that 1334 candidaemia episodes were identified belonging to 1144 individual patients during 2010 to 2020. Candida albicans was the most prevalent species detected in candidaemia patients, representing 57.7% of these episodes. Nakaseomyces (Candida) glabrata and Candida parapsilosis complex showed an increasing trend compared to previous studies, whereas Candida albicans demonstrated a decrease. 19.8% of these episodes were polymicrobial and 17% presented with mixed Candida/bacterial BSIs while 2.8% were mixed fungaemia. C. albicans and N. glabrata were the most common combination (51.4%) in mixed fungaemia episodes. Enterococcus and Lactobacillus spp. were the most common bacteria isolated in mixed Candida/bacterial BSIs. Conclusions: Polymicrobial growth with candidaemia is common, mostly being mixed Candida/bacterial BSIs. C. albicans was detected in more than half of all the candidaemia patients however showed a decreasing trend in time, whereas an increase is noteworthy in C. parapsilosis complex and N. glabrata. [ABSTRACT FROM AUTHOR]

Biofilm polymicrobial infections have gained international attention, especially cases involving fungi and bacteria. Such infections require patients to undergo costly, extended hospital stays and have caused a considerable amount of morbidity and mortality. Polymicrobial biofilms also have greater mortality rates than monomicrobial biofilms. This study aims to evaluate the overall biomass of biofilms produced by Candida albicans interacting with two Gram-positive bacteria: E. faecalis and S. aureus. Tryptic Soy Broth (TSB) medium were used for the bacterial and fungal suspensions. Three 96-well microplates were used for the biofilm cultivation. The microplates were then incubated for 24, 48, and 72 hours at 37˚C. Next, after conducting the Crystal Violet test, the biofilms’ Optical Density (OD) values were measured by an ELISA reader. The mixed species treatment of Candida albicans with S. aureus for 72 hours had the highest average OD value (OD ± SD = 0.903 ± 0.050), while the mixed species treatment of Candida albicans with E. faecalis for 24 hours had the lowest average OD value (OD ± SD = 0.240 ± 0.032). In conclusion, the parameters observed in this study revealed that biofilms could be formed well by polymicrobial interactions between Candida albicans and two Gram-positive bacteria: S. aureus and E. faecalis. [ABSTRACT FROM AUTHOR]

Background: Diabetic foot ulcer (DFU) is a major complication of diabetes mellitus (DM) which is associated with high morbidity and mortality. There is high rate of bacteria colonization especially in those with tendencies for poor wound dressing. This is accompanied by high rate of inappropriate antibiotic usage. The aim of this study is to characterize microbial pathogens colonizing foot ulcers of diabetic patients in Enugu, Nigeria, and to determine the antibiotic susceptibility of these isolates. Methodology: This was a descriptive cross-sectional study of consecutively enrolled diabetic patients with foot ulcers in two tertiary healthcare facilities in Enugu, Nigeria, between May 2021 and February 2022. A structured questionnaire was used to obtain socio-demographic and clinical data of the patients. Pus samples and/or tissues were collected from the ulcer lesion of each patient for aerobic and anaerobic microbial cultures and biochemical identification using standard conventional techniques. Results: A total of 310 diabetic patients with foot ulcers were recruited into the study, with 62.3% (193/310) males and 37.7% (117/310) females, and mean age of 56.0±13.9 years. Bacteria and yeast were isolated from samples of 280 (90.3%) patients while samples of 30 (9.7%) patients had no microbial growth. Males had higher frequency of microbial isolates (90.7%, 175/193) than females (89.7%, 105/117), while the age group ≤ 40 years had higher frequency of microbial isolates (100%, 43/43) compared to other age groups, although the differences are not statistically significant (p>0.05). The distribution of the isolates showed that 15.7% (44/280) were monomicrobial while 84.3% (236/280) were polymicrobial. The highest single isolate was Bacteroides fragilis with 5.0% (14/280), followed by Staphylococcus aureus with 3.2% (9/280). Bacteroides fragilis and S. aureus occurred as the highest combined bacteria isolates with 5.7% (16/280). Most of the patients were colonized by combination of bacterial isolates. The susceptibility indicates that most of the anaerobic bacteria were sensitive to metronidazole while S. aureus isolates were resistant to ofloxacin at a rate of 65.0%. Conclusion: The findings in this study showed that there is high bacteria and fungi colonization of foot ulcers of diabetic patients in Enugu, Nigeria. Routine care of wounds especially frequent changes of dressing materials and the use of potent antiseptics, are recommended. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to investigate an in vitro dynamic bioreactor model by evaluating the antimicrobial effect of clinically relevant amoxicillin doses on polymicrobial microcosm biofilms derived from subgingival plaque. Methods: Biofilms from pooled subgingival plaque were grown for 108 hours in control and experimental dynamic biofilm reactors. Amoxicillin was subsequently infused into the experimental reactor to simulate the pharmacokinetic profile of a standard 500 mg thrice‐daily dosing regimen over 5 days and biofilms were assessed by live/dead staining, scanning electron microscopy, and quantitative polymerase chain reaction. Results: Following establishment of the oral microcosm biofilms, confocal imaging analysis showed a significant increase in dead bacteria at 8 hours (p = 0.0095), 48 hours (p = 0.0070), 96 hours (p = 0.0140), and 120 hours (p < 0.0001) in the amoxicillin‐treated biofilms compared to the control biofilms. Nevertheless, viable bacteria remained in the center of the biofilm at all timepoints. Significant reductions/elimination in Campylobacter rectus, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, and Peptostreptococcus anaerobius was observed among the amoxicillin‐treated biofilms at the 96 and 120 hour timepoints. Conclusion: A novel in vitro dynamic model of oral microcosm biofilms was effective in modeling the antimicrobial effect of a pharmacokinetically simulated clinically relevant dose of amoxicillin. [ABSTRACT FROM AUTHOR]

The interactions between pathogens during infection and the impact of these interactions on drug effectiveness are poorly understood, making polymicrobial infections challenging to treat. During an infection, cross-interactions between bacteria and fungi can strengthen virulence mechanisms and affect how the disease develops. The purpose of this study is to determine how Pseudomonas aeruginosa interacts with Candida glabrata, Candida albicans, Candida krusei, Candida parapsilosis, and Candida tropicalis in the development of polymicrobial biofilms. Pseudomonas aeruginosa, Candida albicans, Candida krusei, Candida parapsilosis, Candida glabrata, and Candida tropicalis isolates were used in this experimental investigation. After preparing a 0.5 Mc Farland suspension of each isolate, the gold standard for measuring biofilm was applied: the Tissue Plate Culture (TCP) method. After that, an ELISA reader with a wavelength of 595 nm was used to measure the optical density (OD) of the biofilm. SPSS 26.0 was then used for statistical analysis to compare the OD values between Pseudomonas aeruginosa that had not been exposed to Candida and those that had. Pseudomonas aeruginosa and Candida are found to interact synergistically if there is an increase in OD, and antagonistic interaction is discovered if there is a decrease in OD. In comparison to the group that was not exposed to Candida, Pseudomonas aeruginosa exposed to Candida albicans, Candida krusei, Candida parapsilosis, Candida glabrata, and Candida tropicalis showed an increase in the OD value of biofilm. Pseudomonas aeruginosa and Candida albicans, Candida glabrata, Candida krusei, Candida parapsilosis, and Candida tropicalis interact synergistically. [ABSTRACT FROM AUTHOR]

ObjectivesWe sought to evaluate the pharmacodynamics of β-lactam antibacterials against polymicrobial communities of clinically relevant gram-positive and gram-negative pathogens.MethodsTwo Enterococcus faecalis isolates, two Staphylococcus aureus isolates, and three Escherichia coli isolates with varying β-lactamase production were evaluated in static time-killing experiments. Each gram-positive isolate was exposed to a concentration array of ampicillin (E. faecalis) or cefazolin (S. aureus) alone and during co-culture with an E. coli isolate that was β-lactamase-deficient, produced TEM-1, or produced KPC-3/TEM-1B. The results of the time-killing experiments were summarized using an integrated pharmacokinetic/pharmacodynamics analysis as well as mathematical modelling to fully characterize the antibacterial pharmacodynamics.ResultsIn the integrated analysis, the maximum killing of ampicillin (Emax) against both E. faecalis isolates was ≥ 4.11 during monoculture experiments or co-culture with β-lactamase-deficient E. coli, whereas the Emax was reduced to ≤ 1.54 during co-culture with β-lactamase-producing E. coli. In comparison to monoculture experiments, culturing S. aureus with KPC-producing E. coli resulted in reductions of the cefazolin Emax from 3.25 and 3.71 down to 2.02 and 2.98, respectively. Two mathematical models were created to describe the interactions between E. coli and either E. faecalis or S. aureus. When in co-culture with E. coli, S. aureus experienced a reduction in its cefazolin Kmax by 24.8% (23.1%RSE). Similarly, β-lactamase-producing E. coli preferentially protected the ampicillin-resistant E. faecalis subpopulation, reducing Kmax,r by 90.1% (14%RSE).Discussionβ-lactamase-producing E. coli were capable of protecting S. aureus and E. faecalis from exposure to β-lactam antibacterials.

Necrotising fasciitis (NF) is a rare but life-threatening skin and soft tissue infection. It requires urgent surgical debridement. The most common cause of monomicrobial NF is invasive Group A Streptococcus (IGAS). We present eight patients who were all treated in a single trauma unit within a 9-month period. All cases required surgical debridement and had positive microbiology testing for IGAS. The eight patients did not present typically for NF, nor did they all have typical risk factors for the development of NF. The in-hospital mortality rate was 37.5%. This series represents an epidemiological spike of IGAS infections causing NF. The findings from this series could inform future practice if similar spikes were to be encountered. [ABSTRACT FROM AUTHOR]

PurposeTo present a case of periorbital and orbital necrotizing fasciitis (PONF) from an odontogenic source with a distinct microbiologic profile and highlight the need for emergent multidisciplinary management.ObservationsA 39-year-old man presented with periorbital swelling, pain, and erythema following facial trauma. Imaging revealed peri-dental collections, accompanying maxillary sinusitis, and pre- and post-septal involvement. Immediate surgical debridement of necrotic tissue along with broad-spectrum antibiotics were pursued for management. Cultures grew multiple organisms, most notably Streptococcus milleri group and Staphylococcus lugdunensis.Conclusions and importancePONF is a rare yet potentially fatal disease. Streptococcus milleri group and a fulminant course are to be suspected when the source is odontogenic. Timely multidisciplinary surgical debridement and medical management with intravenous antibiotics is critical for best outcomes.

Brain abscess is a serious clinical condition caused by a localized collection of pus within the brain tissue. This typically occurs as a result of an infection that originates from a nearby area, such as an ear, sinus, or dental infection, or an infection in the bloodstream. Streptococcus and Staphylococcus species are the most common organisms implicated in brain abscesses. Apart from aerobic growth, cases of mixed infections of both aerobic and anaerobic organisms are also commonly reported in the literature. Herein we report a 23-year-old immunocompetent female with chronic otitis media who presented with cerebellar abscess where the aerobic growth was sterile and anaerobic culture revealed pure growth of dual anaerobes viz... Peptostreptococcus and Bacteroides thetaiotaomicron. This case highlights the importance of prompt diagnosis and management of polymicrobial anaerobic infection in cases of brain abscess. [ABSTRACT FROM AUTHOR]

Flavobacterium covae and virulent Aeromonas hydrophila are prevalent bacterial pathogens within the US catfish industry that can cause high mortality in production ponds. An assessment of in vivo bacterial coinfection with virulent A. hydrophila (ML09‐119) and F. covae (ALG‐00‐530) was conducted in juvenile channel catfish (Ictalurus punctatus). Catfish were divided into seven treatments: (1) mock control; (2) and (3) high and low doses of virulent A. hydrophila; (4) and (5) high and low doses of F. covae; (6) and (7) simultaneous challenge with high and low doses of virulent A. hydrophila and F. covae. In addition to the mortality assessment, anterior kidney and spleen were collected to evaluate immune gene expression, as well as quantify bacterial load by qPCR. At 96 h post‐challenge (hpc), the high dose of virulent A. hydrophila infection (immersed in 2.3 × 107 CFU mL−1) resulted in cumulative percent mortality (CPM) of 28.3 ± 9.5%, while the high dose of F. covae (immersed in 5.2 × 106 CFU mL−1) yielded CPM of 23.3 ± 12.9%. When these pathogens were delivered in combination, CPM significantly increased for both the high‐ (98.3 ± 1.36%) and low‐dose combinations (76.7 ± 17.05%) (p < .001). Lysozyme activity was found to be different at 24 and 48 hpc, with the high‐dose vAh group demonstrating greater levels than unexposed control fish at each time point. Three proinflammatory cytokines (tnfα, il8, il1b) demonstrated increased expression levels at 48 hpc. These results demonstrate the additive effects on mortality when these two pathogens are combined. The synthesis of these mortality and health metrics advances our understanding of coinfections of these two important catfish pathogens and will aid fish health diagnosticians and channel catfish producers in developing therapeutants and prevention methods to control bacterial coinfections. [ABSTRACT FROM AUTHOR]

Bacterial infections are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus cause chronic co-infections, which are more problematic than mono-species infections. Understanding the mechanisms of their interactions is crucial for treating co-infections. Staphyloxanthin (STX), a yellow pigment synthesized by the S. aureus crt operon, promotes S. aureus resistance to oxidative stress and neutrophil-mediated killing. We found that STX production by S. aureus, either as surface-grown macrocolonies or planktonic cultures, was elevated when exposed to the P. aeruginosa exoproduct, 2-heptyl-4-hydroxyquinoline N-oxide (HQNO). This was observed with both mucoid and non-mucoid P. aeruginosa strains. The induction phenotype was found in a majority of P. aeruginosa and S. aureus clinical isolates examined. When subjected to hydrogen peroxide or human neutrophils, P. aeruginosa survival was significantly higher when mixed with wild-type (WT) S. aureus, compared to P. aeruginosa alone or with an S. aureus crt mutant deficient in STX production. In a murine wound model, co-infection with WT S. aureus, but not the STX-deficient mutant, enhanced P. aeruginosa burden and disease compared to mono-infection. In conclusion, we identified a role for P. aeruginosa HQNO mediating polymicrobial interactions with S. aureus by inducing STX production, which consequently promotes resistance to the innate immune effectors H2O2 and neutrophils. These results further our understanding of how different bacterial species cooperatively cause co-infections. [ABSTRACT FROM AUTHOR]

Background: Chronic suppurative otitis media (CSOM) is one of the commonest illnesses which require urgent medical treatment especially in children's of poor socioeconomic status. The aim of present study was conducted to evaluate the different aerobic and anaerobic microorganisms causing csom in paediatric and adult patients and their antimicrobial sensitivity pattern as a guide to therapy. Materials and methods: A total of 106 clinically diagnosed cases of csom patients were included in the study, out of which 74 patients belong to paediatric csom and 32 cases were adult csom. From all the patients 106 samples were collected aseptically and processed according to standard CLSI Guidelines. Results: Out of 74 paediatric csom patients, 68 patients (91.89%) were bacterial culture positive while out of 32 adult's csom patients, 26 patients (81.25%) were culture positive. Bilateral csom was slightly more common in adults than paediatric age group. Polymicrobial nature of csom was noted in both paediatric and adult cases while number of organisms isolated per lesion was slightly higher in adults as compared to paediatrics cases. Staphyloccocus aureus was the commonest aerobic isolate in paediatric age groups csom, while in adult Pseudomonas aeruginosa was the commonest one. Among anaerobic culture Peptostreptococcus spp was commonest in paediatrics csom whereas Prevotella melaninogenica in adult csom. Sensitivity of S. aureus to Doxycycline, Clindamycin, Linezolid were 100%, piperacillin + Tazobacatum 94.59%, cefuroxime was 86.48% while that of gram negative bacilli was higher to cefuroxime, ceftriaxone, Azithromycin, Clindamycin, Doxycycline 90 to 100%. Among anaerobes higher sensitivity was seen to metronidazole (100%), clindamycin (100%) and ceftriaxone (100%). Conclusion: In view of the polymicrobial etiology of csom, prompt appropriate antimicrobial therapy can effectively reverse the disease process thereby preventing longterm sequelae. [ABSTRACT FROM AUTHOR]

Background: Necrotizing fasciitis is rapidly progressive, lethaldestructive inflammation with polymicrobial infection and secondary necrosis. Though it is a disease described from the Hippocratic era, there is an increase in the incidence of necrotizing fasciitis. The most important factors determining the outcome of the disease are early diagnosis and aggressive debridement. Materials and Methods: Cross-sectional descriptive study was conducted in a tertiary care teaching hospital's surgical ward. A total of 50 patients, diagnosed with necrotizing fasciitis based on the criteria set were included in the study. After detailed clinical and laboratory evaluation, appropriate and adequate surgical and medical interventions were administered and were followed to note the outcome. Results: The majority of patients were over 40 years old and 74% of them were male. 72% of them had fever, 88% of them had tenderness. 68% of the patients had involvement of the lower extremities. Trauma was the predominant triggering factor and diabetes, the most commonly associated predisposing disease present in 72% of patients. 84% of the infections were polymicrobial and E. coli was isolated from 74% of them. 4 patients succumbed to the disease and 6 patients needed amputations as a life-saving measure. Acidosis and hypoalbuminemia were the most common independent predictive factors for mortality. Once sepsis is overcome and the granulation tissue is formed, the wound is covered with an SSG or flap cover. Conclusion: The aggressive and destructive course of necrotizing fasciitis could lead to morbidity and mortality. Early recognition, aggressive debridement are the essential steps for recovery. Though broad-spectrum antibiotics started as empirical therapy to avoid the catastrophe of septic shock, appropriate antibiotics should be started as the disease is often polymicrobial. Acidosis, truncallocation, leucocytosis and decreased albumin were found to be factors strongly associated with mortality. [ABSTRACT FROM AUTHOR]

A retrospective descriptive study included patients admitted with severe burns over the course of 10 years (2008–2018). Across all patients, there were 39 different species of bacteria, with 23 species being Gram-negative and 16 being Gram-positive bacteria, with also five different species of fungi cultured. Pseudomonas aeruginosa was the most commonly isolated organism, with 57.45% of patients having a positive culture. There was a significant difference in the number of P. aeruginosa isolated from patients that acquired their burns at work, in a garden, inside a vehicle, in a garage or in a public place. In patients that were positive for P. aeruginosa, the number of operations was higher (2.4) and the length of stay was significantly increased (80.1 days). Patients that suffered from substance abuse demonstrated significantly higher numbers of isolated P. aeruginosa (14.8%). Patients that suffered from both mental health illness and substance abuse demonstrated significantly higher numbers of P. aeruginosa isolated (18.5%). In the P. aeruginosa-negative group, there were significantly fewer patients that had been involved in a clothing fire. Furthermore, in the P. aeruginosa-negative patient cohort, the mortality rate was significantly higher (p = 0.002). Since the incidence of P. aeruginosa was also associated with a decreased mortality rate, it may be that patients admitted to hospital for shorter periods of time were less likely to be colonised with P. aeruginosa. This study demonstrates novel factors that may increase the incidence of P. aeruginosa isolated from burn patients. [ABSTRACT FROM AUTHOR]

Background Accurate measurement of disease associated with endemic bacterial agents in pig populations is challenging due to their commensal ecology, the lack of disease-specific antemortem diagnostic tests, and the polymicrobial nature of swine diagnostic cases. The main objective of this retrospective study was to estimate temporal patterns of agent detection and disease diagnosis for five endemic bacteria that can cause systemic disease in porcine tissue specimens submitted to the Iowa State University Veterinary Diagnostic Laboratory (ISU VDL) from 2017 to 2022. The study also explored the diagnostic value of specific tissue specimens for disease diagnosis, estimated the frequency of polymicrobial diagnosis, and evaluated the association between phase of pig production and disease diagnosis. Results S. suis and G. parasuis bronchopneumonia increased on average 6 and 4.3%, while S. suis endocarditis increased by 23% per year, respectively. M. hyorhinis and A. suis associated serositis increased yearly by 4.2 and 12.8%, respectively. A significant upward trend in M. hyorhinis arthritis cases was also observed. In contrast, M. hyosynoviae arthritis cases decreased by 33% average/year. Investigation into the diagnostic value of tissues showed that lungs were the most frequently submitted sample, However, the use of lung for systemic disease diagnosis requires caution due to the commensal nature of these agents in the respiratory system, compared to systemic sites that diagnosticians typically target. This study also explored associations between phase of production and specific diseases caused by each agent, showcasing the role of S. suis arthritis in suckling pigs, meningitis in early nursery and endocarditis in growing pigs, and the role of G. parasuis, A. suis, M. hyorhinis and M. hyosynoviae disease mainly in post-weaning phases. Finally, this study highlighted the high frequency of co-detection and -disease diagnosis with other infectious etiologies, such as PRRSV and IAV, demonstrating that to minimize the health impact of these endemic bacterial agents it is imperative to establish effective viral control programs. Conclusions Results from this retrospective study demonstrated significant increases in disease diagnosis for S. suis, G. parasuis, M. hyorhinis, and A. suis, and a signifcant decrease in detection and disease diagnosis of M. hyosynoviae. High frequencies of interactions between these endemic agents and with viral pathogens was also demonstrated. Consequently, improved control programs are needed to mitigate the adverse effect of these endemic bacterial agents on swine health and wellbeing. This includes improving diagnostic procedures, developing more effective vaccine products, fne-tuning antimicrobial approaches, and managing viral co-infections. [ABSTRACT FROM AUTHOR]

Proteus mirabilis is a common uropathogen and a leading cause of catheter-associated urinary tract infections (CAUTIs), which are often polymicrobial. Through a genome-wide screen, we previously identified two [NiFe] hydrogenases as candidate fitness factors for P. mirabilis CAUTI: a Hyb-type Group 1c H2-uptake hydrogenase and a Hyf-type Group 4a H2-producing hydrogenase. In this study, we disrupted one gene of each system (hyfE and hybC) and also generated a double mutant to examine the contribution of flexible H2 metabolism to P. mirabilis growth and fitness in vitro and during experimental CAUTI. Since P. mirabilis is typically present as part of a polymicrobial community in the urinary tract, we also examined the impact of two common co-colonization partners, Providencia stuartii and Enterococcus faecalis, on the expression and contribution of each hydrogenase to fitness. Our data demonstrate that neither system alone is critical for P. mirabilis growth in vitro or fitness during experimental CAUTI. However, perturbation of flexible H2 metabolism in the ∆hybC∆hyfE double mutant decreased P. mirabilis fitness in vitro and during infection. The Hyf system alone contributed to the generation of proton motive force and swarming motility, but only during anaerobic conditions. Unexpectedly, both systems contributed to benzyl viologen reduction in TYET medium, and disruption of either system increased expression of the other. We further demonstrate that polymicrobial interactions with P. stuartii and E. faecalis alter the expression of Hyb and Hyf in vitro as well as the contribution of each system to P. mirabilis fitness during CAUTI. [ABSTRACT FROM AUTHOR]

Background: Necrotising fasciitis (NF) is a fulminant soft tissue infection that requires timely diagnosis, urgent surgical debridement, and appropriate antimicrobial therapy. The choice of empiric antimicrobial therapy depends on the microorganisms cultured and the antimicrobial resistance profile of the institution. Necrotising fasciitis has not been studied in our setting. Objectives: The aim of the study was to audit the microbiological profile of NF and antimicrobial susceptibility profile. Method: This was a retrospective study in a secondary level hospital from the period of 2014–2020. The patients’ demographic data, clinical features, location of infection, comorbidities, laboratory and microbiological profiles were analysed. Results: There were 53 patients during 2014–2020 with median age of 45.5 (38.5–56.0) years. The majority of the patients were males (35 [66.04%]), had no comorbidities (25 [47.17%]), and the lower limb was the most common anatomic site (17 [32.08%]). Type II (monomicrobial) NF was the predominant type (31 [58.49%]). Staphylococcus aureus was the most prevalent Gram-positive bacteria (18 [38%]) and Escherichia coli, the main species isolated in the Gram-negative bacteria (14 [36%]) with susceptibility to cloxacillin (94%) and amoxicillin and/or clavulanic acid (92%), respectively. Conclusion: Staphylococcus aureus and Escherichia coli were the most common bacteria with low rate of antimicrobial resistance. Amoxicillin and/or clavulanic acid and an adjunctive clindamycin are appropriate antimicrobial therapy for empiric treatment for NF in our setting. Contribution: Amoxicillin and/or clavulanic acid and an adjunctive clindamycin can be used as an empiric treatment for NF.

Polymicrobial endocarditis is uncommon, and polymicrobial endocarditis in combination with Coxiella burnetii is very rare. We herein describe an extremely rare case of polymicrobial bivalvular endocarditis due to coinfection with Enterococcus faecalis and Coxiella burnetii in a 62-year-old male patient, and extensively review the relevant medical literature. To the best of our knowledge, only three similar cases have been previously reported. Q fever is a worldwide endemic bacterial zoonosis, but it and its most common chronic complication, endocarditis, are still underestimated and underdiagnosed worldwide. This situation reflects the paucity of reported cases of polymicrobial endocarditis in combination with Coxiella burnetii. Clinical presentation of Q fever endocarditis is highly nonspecific, and diagnosis may be delayed or missed, leading to severe and potentially fatal disease. Our case and the previously reported similar cases emphasize the need for further evaluation of infective endocarditis due to Coxiella burnetii, in all cases of culture-negative endocarditis, and in prolonged oligo-symptomatic inflammatory syndrome, particularly in the presence of valvular heart disease. This approach should be applied even when typical pathogens are isolated, especially in endemic areas of Q fever, and with atypical presentation.

A recent workshop titled "Developing Models to Study Polymicrobial Infections," sponsored by the Dartmouth Cystic Fibrosis Center (DartCF), explored the development of new models to study the polymicrobial infections associated with the airways of persons with cystic fibrosis (CF). The workshop gathered 35+ investigators over two virtual sessions. Here, we present the findings of this workshop, summarize some of the challenges involved with developing such models, and suggest three frameworks to tackle this complex problem. The frameworks proposed here, we believe, could be generally useful in developing new model systems for other infectious diseases. Developing and validating new approaches to study the complex polymicrobial communities in the CF airway could open windows to new therapeutics to treat these recalcitrant infections, as well as uncovering organizing principles applicable to chronic polymicrobial infections more generally.

A recent workshop titled "Developing Models to Study Polymicrobial Infections," sponsored by the Dartmouth Cystic Fibrosis Center (DartCF), explored the development of new models to study the polymicrobial infections associated with the airways of persons with cystic fibrosis (CF). The workshop gathered 35+ investigators over two virtual sessions. Here, we present the findings of this workshop, summarize some of the challenges involved with developing such models, and suggest three frameworks to tackle this complex problem. The frameworks proposed here, we believe, could be generally useful in developing new model systems for other infectious diseases. Developing and validating new approaches to study the complex polymicrobial communities in the CF airway could open windows to new therapeutics to treat these recalcitrant infections, as well as uncovering organizing principles applicable to chronic polymicrobial infections more generally.

Biofilm infection occurs in 80% of chronic infections caused by 60% of biofilms from plankton cells and polymicrobial biofilms. Due to synergistic interactions between species, infections caused by polymicrobial biofilms are more virulent than monospecies biofilm infections. New anti-biofilm candidates are constantly being developed by tracing the content of active compounds from medicinal plants native to Indonesia. The need to find new plant sources that have the potential as anti-biofilms is increasingly needed along with increasing microbial resistance. Various studies show that active compounds that have anti-biofilm potential are polyphenols, quercetin, curcumin, gallic acid, and ferulic acid. The mechanism of action of anti-biofilms is through the prevention of attachment and formation of biofilms, inhibition of quorum sensing, and inhibition of gene expression in microbes.

Intra-abdominal infections (IAI) are surgical emergencies ranging from appendicitis to peritonitis and intrahepatic infections. Anaerobic bacteria including Bacteroides spp. and Clostridium spp. cause 30–50 % of these infections. Slackia exigua (S.exigua) is an obligate anaerobe part of the human oral microbiota and has been associated with periodontal problems. In this report, we describe a rare occurrence of polymicrobial infection with four anaerobes including S. exigua in a patient with peritonitis caused by a hidden ileal perforation.

Necrotizing fasciitis (NF) is a rare life-threatening skin and soft tissue infection. Most commonly the result of trauma, it rapidly spreads through the fascial planes and causes necrosis of the subcutaneous tissues. The disease is classified into different types depending on the underlying bacteria responsible, with Group A streptococcus reported as the most common organism found. Reaching a diagnosis of NF is often challenging due to its non-specific signs and symptoms. A delay to recognition and treatment significantly increases the risk of mortality. Risk scoring systems can be helpful to assist with diagnosis. Patients typically present with symptoms of systemic infection and sepsis which requires management in an intensive care setting. The treatment for NF is aggressive surgical debridement and the provision of broad-spectrum cover with intravenous antibiotics. Although it is uncommon, knowledge of this life-threatening emergency is essential for surgical trainees across all specialties. [ABSTRACT FROM AUTHOR]

Ludwig's angina was first described in 1839 by German physician, Wilhelm Frederick Von Ludwig as a rapidly and fatal progressive gangrenous cellulitis and edema of the soft tissues of the neck and floor of the mouth with rapid spread to other places like anterior mediastinum. However, Type 2 acute myocardial infarction (MI) due to Ludwig's angina has not been documented. A 62‐year‐old male presented to the emergency department with visible anterior neck swelling for 1 week, which was preceded by a tooth arch 1 week prior, the patient presented with a high grade fevers, dysphonia, dysphagia, and facial swelling. No history of trauma. He reported in the past 24 h prior to evaluation, a steady progression of pain intensity with rapid progression and anterior neck skin erythema and swelling. The pain was exacerbated by rotation of the neck, tongue protrusion, and speaking. On examination, there was a visible anterior neck swelling measuring 10.0 × 3.0 cm in widest dimensions, exquisitely tender to palpation with a positive temperature gradient, skin hyperpigmentation and firm in consistency, no crepitus, fluctuance, or induration. Tongue appeared elevated with sublingual edema and pooling of secretions. No stridor. A chest and neck ultrasound scan revealed an extensive abscisic mass from the submandibular, neck, sternal notch, and right clavicular region with the largest pockets measuring 2.11 × 0.8 cm, 2.03 × 0.62 cm, 1.50 × 1.1 cm, with noted submandibular, subclavicular and deep and superficial cervical lymph nodes, the largest measuring 1.23 × 1.63 cm in dimensions. A neck‐CT scan with contrast revealed a pronounced subcutaneous tissue localized collection extending to both submandibular spaces measuring about 5.5 × 12.5 × 9.5 cm with mural enhancement. The upper chest cuts showed moderate pleural effusions and a paracardial hypodense well‐defined lesion measuring 7.5 × 2.5 cm with mild pericardial effusion. The patient was referred to the ear, neck and throat, ENT surgeon for urgent drainage of the abscess, which was done successfully and about 300 mL of hemorrhagic pus was drained. Then transferred to highly dependent unit, (HDU) for IV antibiotic administration and vital observations, prior to that electrocardiogram, ECG showed a normal sinus rhythm. The following day in HDU, the patient started experiencing a chest pain of sudden onset radiating to the upper jaws, left forearm and throbbing in nature, palpitations and started becoming diaphoretic. Blood pressure was 150/70 mmgh and pulse of 120 bpm. ECG readings demonstrated ST‐elevation, at lead 11, V2, and V3, cardiac Troponin I and CK‐MB were elevated 10.0 ng/mL, (<0.4 ng/mL) and 150.0 IU/L, (5‐25 IU/L) respectively. The patient was started on medications to relief acute ischemic pain these included, sublingual nitroglycerin 0.6 mg, morphine 5 mg intravenous slowly, antithrombotic, and beta‐adrenergic blockade. He was kept in HDU later with heparin 80 U/kg bolus and 8 U/kg continuous infusion and was taken for coronary angiogram which demonstrated no any coronary artery occlusion. The patient later on started to register improvement and later discharged on medications for follow‐up. On follow‐up, the subsequent ECG showed persistent atrial fibrillation and patient was discharged on P2Y12 inhibitor, clopidogrel, 75 mg, and beta‐blocker, metoprolol 50 mg. Over the past three decades, mortality rates for acute MI have increased significantly, One common subtype, type 2 MI is noted and driven by a myocardial oxygen supply and demand mismatch in the absence of coronary thrombosis. T2MI can occur with or without obstructive coronary disease like in this patients with angiographically normal coronary arteries. T2MI is increasingly recognized because of various septic pathophyisologies that cause increased myocardia oxygen demand. Evidence of myocardial ischemia especially those with sepsis are likely to develop myocardial injury. T2MI is frequent and explains a significant increase in clinical practice. A consensus is needed about how the diagnosis is established, to facilitate evidence‐based therapies geared toward improving outcomes. [ABSTRACT FROM AUTHOR]

Acinetobacter baumannii) ABSTRACT: Background: Biofilms are composed of more than one species or often called polymicrobial biofilms, so research is needed on the formation of polymicrobial biofilms, especially between fungi and bacteria. This study aimed to analyze the total biomass and metabolic activity of biofilms formed from the interaction of fungi (Candida tropicalis) with bacteria (Staphylococcus aureus, MRSA, Pseudomonas aeruginosa, and Acinetobacter baumannii); Methods: Bacterial and fungal cultures were suspended in Tryptic Soy Broth (TSB) medium, then biofilm was cultivated in two 96-well microplates, then the microplates were incubated at 37 degrees Celsius for 48 hours. Detection of the biofilm will be carried out using the Crystal Violet assay and reduction of the tetrazolium salt (3-(4,5-dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide), or MTT assay to obtain the Optical Density (OD) value by using ELISA reader; Results: The results of this study obtained significant data from both parameters, the highest average value was found in the C. tropicalis treatment group (2,412 ± 0.825 on the biomass test results; 1,525 ± 0.473 on the metabolic activity test results), while the lowest was seen in the S. aureus treatment group (0.512 ± 0.224 in the biomass test results; 0.978 ± 0.349 in the metabolic activity test results); and Conclusions: In the total biomass parameter, it was obtained that the biofilm biomass could be formed strongly in each treatment, while the results of the metabolic activity showed that each treatment was able to carry out cell proliferation. [ J Adv Biotechnol Exp Ther 2023; 6(1.000): 84-93]

One of the most feared complications of diabetes is diabetic foot, which is also the main cause of hospitalisation in diabetic individuals. In order to pick the appropriate antibiotics for the effective management of these illnesses, it is essential to have a solid understanding of the prevalent microorganisms that have been isolated and their respective antibiograms. [ABSTRACT FROM AUTHOR]

ABSTRACT The study of human commensal bacteria began with the first observation of prokaryotes >340 years ago. Since then, the study of human-associated microbes has been justifiably biased toward the study of infectious pathogens. However, the role of commensal microbes has in recent years begun to be understood with some appreciation of them as potential protectors of host health rather than bystanders. As our understanding of these valuable microbes grows, it highlights how much more remains to be learned about them and their roles in maintaining health. We note here that a thorough framework for the study of commensals, both in vivo and in vitro is overall lacking compared to well-developed methodologies for pathogens. The modification and application of methods for the study of pathogens can work well for the study of commensals but is not alone sufficient to properly characterize their relationships. This is because commensals live in homeostasis with the host and within complex communities. One difficulty is determining which commensals have a quantifiable impact on community structure and stability as well as host health, vs benign microbes that may indeed serve only as bystanders. Human microbiomes are composed of bacteria, archaea, fungi, and viruses. This review focuses particularly on oral bacteria, yet many of the principles of commensal impacts on host health observed in the mouth can translate well to other host sites. Here, we discuss the value of commensals, the shortcomings involved in model systems for their study, and some of the more notable impacts they have upon not only each other but host health.

ABSTRACT Polymicrobial biofilms are present in many environments particularly in the human oral cavity where they can prevent or facilitate the onset of disease. While recent advances have provided a clear picture of both the constituents and their biogeographic arrangement, it is still unclear what mechanisms of interaction occur between individual species in close proximity within these communities. In this study, we investigated two mechanisms of interaction between the highly abundant supragingival plaque (SUPP) commensal Corynebacterium matruchotii and Streptococcus mitis which are directly adjacent/attached in vivo. We discovered that C. matruchotii enhanced the fitness of streptococci dependent on its ability to detoxify streptococcal-produced hydrogen peroxide and its ability to oxidize lactate also produced by streptococci. We demonstrate that the fitness of adjacent streptococci was linked to that of C. matruchotii and that these mechanisms support the previously described “corncob” arrangement between these species but that this is favorable only in aerobic conditions. Furthermore, we utilized scanning electrochemical microscopy to quantify lactate production and consumption between individual bacterial cells for the first time, revealing that lactate oxidation provides a fitness benefit to S. mitis not due to pH mitigation. This study describes mechanistic interactions between two highly abundant human commensals that can explain their observed in vivo spatial arrangements and suggest a way by which they may help preserve a healthy oral bacterial community. IMPORTANCE As the microbiome era matures, the need for mechanistic interaction data between species is crucial to understand how stable microbiomes are preserved, especially in healthy conditions where the microbiota could help resist opportunistic or exogenous pathogens. Here we reveal multiple mechanisms of interaction between two commensals that dictate their biogeographic relationship to each other in previously described structures in human supragingival plaque. Using a novel variation for chemical detection, we observed metabolite exchange between individual bacterial cells in real time validating the ability of these organisms to carry out metabolic crossfeeding at distal and temporal scales observed in vivo. These findings reveal one way by which these interactions are both favorable to the interacting commensals and potentially the host.

Abstract Ludwig's angina was first described in 1839 by German physician, Wilhelm Frederick Von Ludwig as a rapidly and fatal progressive gangrenous cellulitis and edema of the soft tissues of the neck and floor of the mouth with rapid spread to other places like anterior mediastinum. However, Type 2 acute myocardial infarction (MI) due to Ludwig's angina has not been documented. A 62‐year‐old male presented to the emergency department with visible anterior neck swelling for 1 week, which was preceded by a tooth arch 1 week prior, the patient presented with a high grade fevers, dysphonia, dysphagia, and facial swelling. No history of trauma. He reported in the past 24 h prior to evaluation, a steady progression of pain intensity with rapid progression and anterior neck skin erythema and swelling. The pain was exacerbated by rotation of the neck, tongue protrusion, and speaking. On examination, there was a visible anterior neck swelling measuring 10.0 × 3.0 cm in widest dimensions, exquisitely tender to palpation with a positive temperature gradient, skin hyperpigmentation and firm in consistency, no crepitus, fluctuance, or induration. Tongue appeared elevated with sublingual edema and pooling of secretions. No stridor. A chest and neck ultrasound scan revealed an extensive abscisic mass from the submandibular, neck, sternal notch, and right clavicular region with the largest pockets measuring 2.11 × 0.8 cm, 2.03 × 0.62 cm, 1.50 × 1.1 cm, with noted submandibular, subclavicular and deep and superficial cervical lymph nodes, the largest measuring 1.23 × 1.63 cm in dimensions. A neck‐CT scan with contrast revealed a pronounced subcutaneous tissue localized collection extending to both submandibular spaces measuring about 5.5 × 12.5 × 9.5 cm with mural enhancement. The upper chest cuts showed moderate pleural effusions and a paracardial hypodense well‐defined lesion measuring 7.5 × 2.5 cm with mild pericardial effusion. The patient was referred to the ear, neck and throat, ENT surgeon for urgent drainage of the abscess, which was done successfully and about 300 mL of hemorrhagic pus was drained. Then transferred to highly dependent unit, (HDU) for IV antibiotic administration and vital observations, prior to that electrocardiogram, ECG showed a normal sinus rhythm. The following day in HDU, the patient started experiencing a chest pain of sudden onset radiating to the upper jaws, left forearm and throbbing in nature, palpitations and started becoming diaphoretic. Blood pressure was 150/70 mmgh and pulse of 120 bpm. ECG readings demonstrated ST‐elevation, at lead 11, V2, and V3, cardiac Troponin I and CK‐MB were elevated 10.0 ng/mL, (

A 71-year-old male a chronic smoker, who also had diabetes mellitus and hypertension presented with complaints of fever, cough with foul-smelling sputum and dyspnoea for 25 days. Coarse crepitations were evident in the interscapular area, infrascapular, axillary, infra-axillary and mammary areas on the left side. Contrast-enhanced computed tomography of the chest showed necrotic mediastinal lymph nodes and areas of consolidation in the left upper lobe. Bronchoalveolar lavage fluid polymerase chain reaction identified Staphylococcus, New Delhi metallo-β-lactamase (NDM) producing Klebsiella; GeneXpert detected Mycobacterium tuberculosis complex. Pleural fluid analysis was suggestive of exudative effusion with elevated adenosine deaminase. The patient was managed with anti-tuberculosis treatment, ceftazidime-avibactam, aztreonam and linezolid. [ABSTRACT FROM AUTHOR]

The checkerboard assay is a well-established tool used to determine the antimicrobial effects of two compounds in combination. Usually, data collected from the checkerboard assay use visible turbidity and optical density as a readout. While helpful in traditional checkerboard assays, these measurements become less useful in a polymicrobial context as they do not enable assessment of the drug effects on the individual members of the community. The methodology described herein allows for the determination of cell viability through selective and differential plating of each individual species in a community while retaining much of the high-throughput nature of a turbidity-based analysis and requiring no specialized equipment. This methodology further improves turbidity-based measurements by providing a distinction between bacteriostatic versus bactericidal concentrations of antibiotics. Herein, we use this method to demonstrate that the clinically used antibiotic combination of ceftazidime and gentamicin works synergistically against Pseudomonas aeruginosa in monoculture but antagonistically in a polymicrobial culture also containing Acinetobacter baumannii, Staphylococcus aureus, and Enterococcus faecalis, highlighting the fundamental importance of this methodology in improving clinical practices. We propose that this method could be implemented in clinical microbiology laboratories with minimal impact on the overall time for diagnosis. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa dominates the complex polymicrobial cystic fibrosis (CF) airway and is a leading cause of death in persons with CF. Interestingly, oral streptococcal colonization has been associated with stable CF lung function. The most abundant streptococcal species found in stable patients, Streptococcus salivarius, has been shown to downregulate pro-inflammatory cytokines in multiple colonization models. However, no studies have demonstrated how S. salivarius potentially improves lung function. Our lab previously demonstrated that the P. aeruginosa exopolysaccharide Psl promotes S. salivarius biofilm formation in vitro, suggesting a possible mechanism by which S. salivarius is incorporated into the CF airway microbial community. In this study, we demonstrate that co-infection of rats leads to enhanced S. salivarius colonization and reduced P. aeruginosa colonization. Histological scores for tissue inflammation and damage are lower in dual-infected rats compared to P. aeruginosa infected rats. Additionally, pro-inflammatory cytokines IL-1β, IL-6, CXCL2, and TNF-α are downregulated during co-infection compared to P. aeruginosa single-infection. Lastly, RNA sequencing of cultures grown in synthetic CF sputum revealed that P. aeruginosa glucose metabolism genes are downregulated in the presence of S. salivarius, suggesting a potential alteration in P. aeruginosa fitness during co-culture. Overall, our data support a model in which S. salivarius colonization is promoted during co-infection with P. aeruginosa, whereas P. aeruginosa airway bacterial burden is reduced, leading to an attenuated host inflammatory response. [ABSTRACT FROM AUTHOR]

VAP due to multidrug-resistant (MDR) bacteria is a frequent infection among patients in ICUs. Patient characteristics and mortality in mono- and polybacterial cases of VAP may differ. A single-centre, retrospective 3-year study was conducted in the four ICUs of a Lithuanian referral university hospital, aiming to compare both the clinical features and the 60-day ICU all-cause mortality of monobacterial and polybacterial MDR Klebsiella spp. VAP episodes. Of the 86 MDR Klebsiella spp. VAP episodes analyzed, 50 (58.1%) were polybacterial. The 60-day mortality was higher (p < 0.05) in polybacterial episodes: overall (50.0 vs. 27.8%), in the sub-group with less-severe disease (SOFA < 8) at VAP onset (45.5 vs. 15.0%), even with appropriate treatment (41.7 vs. 12.5%), and the sub-group of extended drug-resistant (XDR) Klebsiella spp. (46.4 vs. 17.6%). The ICU mortality (44.0 vs. 22.5%) was also higher in the polybacterial episodes. The monobacterial MDR Klebsiella spp. VAP was associated (p < 0.05) with prior hospitalization (61.1 vs. 40.0%), diabetes mellitus (30.6 vs. 5.8%), obesity (30.6 vs. 4.7%), prior antibiotic therapy (77.8 vs. 52.0%), prior treatment with cephalosporins (66.7 vs. 36.0%), and SOFA cardiovascular ≥ 3 (44.4 vs. 10.0%) at VAP onset. Patients with polybacterial VAP were more likely (p < 0.05) to be comatose (22.2 vs. 52.0%) and had a higher SAPS II score (median [IQR] 45.0 [35.25–51.1] vs. 50.0 [40.5–60.75]) at VAP onset. Polybacterial MDR Klebsiella spp. VAP had distinct demographic and clinical characteristics compared to monobacterial, and was associated with poorer outcomes. [ABSTRACT FROM AUTHOR]

A 71-year-old male a chronic smoker, who also had diabetes mellitus and hypertension presented with complaints of fever, cough with foul-smelling sputum and dyspnoea for 25 days. Coarse crepitations were evident in the interscapular area, infrascapular, axillary, infra-axillary and mammary areas on the left side. Contrast-enhanced computed tomography of the chest showed necrotic mediastinal lymph nodes and areas of consolidation in the left upper lobe. Bronchoalveolar lavage fluid polymerase chain reaction identified Staphylococcus, New Delhi metallo-β-lactamase (NDM) producing Klebsiella; GeneXpert detected Mycobacterium tuberculosis complex. Pleural fluid analysis was suggestive of exudative effusion with elevated adenosine deaminase. The patient was managed with anti-tuberculosis treatment, ceftazidime-avibactam, aztreonam and linezolid.