Rectal Samples Research Articles

Mucosal microbiome is predictive of pediatric Crohn's disease across geographic regions in North America.

Background: Patients with Crohn's disease (CD) have an altered intestinal microbiome, which may facilitate novel diagnostic testing. However, accuracy of microbiome classification models across geographic regions may be limited. Therefore, we sought to examine geographic variation in the microbiome of patients with CD from North America and test the performance of a machine learning classification model across geographic regions. Methods: The RISK cohort included 447 pediatric patients with CD and 221 non-inflammatory bowel disease controls from across North America. Terminal ileum, rectal and fecal samples were obtained prior to treatment for microbiome analysis. We divided study sites into 3 geographic regions to examine regional microbiome differences. We trained and tested the performance of a machine learning classification model across these regions. Results: No differences were seen in the mucosal microbiome of patients with CD across regions or in either the fecal or mucosal microbiomes of controls. Machine learning classification algorithms for patients with CD performed well across regions (area under the receiver operating characteristic curve [AUROC] range of 0.85-0.91) with the best results from terminal ileum. Conclusions: This study demonstrated the feasibility of microbiome based diagnostic testing in pediatric patients with CD within North America, independently from regional influences.

Molecular surveillance of potential SARS-CoV-2 reservoir hosts in wildlife rehabilitation centers

Background The COVID-19 pandemic, caused by SARS-CoV-2 infection, has become the most devastating zoonotic event in recent times, with negative impacts on both human and animal welfare as well as on the global economy. Although SARS-CoV-2 is considered a human virus, it likely emerged from animals, and it can infect both domestic and wild animals. This constitutes a risk for human and animal health including wildlife with evidence of SARS-CoV-2 horizontal transmission back and forth between humans and wild animals. Aim Molecular surveillance in different wildlife rehabilitation centers and wildlife associated institutions in Chile, which are critical points of animal-human interaction and wildlife conservation, especially since the aim of wildlife rehabilitation centers is to reintroduce animals to their original habitat. Materials and Methods The survey was conducted in six WRCs and three wildlife associated institutions. A total of 185 samples were obtained from 83 individuals belonging to 15 different species, including vulnerable and endangered species. Each specimen was sampled with two different swabs: one oropharyngeal or nasopharyngeal according to the nostril diameter, and/or a second rectal sample. RNA was extracted from the samples and two different molecular assays were performed: first, a conventional RT-PCR with pan-coronavirus primers and a second SARS-CoV-2 qPCR targeting the N and S genes. Results All 185 samples were negative for SARS-CoV-2. Clinical relevance This study constitutes the first report on the surveillance of SARS-CoV-2 from wildlife treated in rehabilitation centers in Chile, and supports the biosafety procedures adopted in those centers.

Inferring the Postmortem Interval of Rat Cadaver after Boiling Water Treatment Based on Microbial Community Succession

Abstract Background: In forensic investigations, accurate estimation of the postmortem interval (PMI) is an important task, but also an ongoing challenge. Especially in cases where the cadaver has been specially treated, for example, by boiling, the determination of PMI becomes extremely difficult. Previous studies have shown that the succession of the microbial community after decomposition of the cadaver can be used to infer PMI. However, the feasibility of determining the PMI of boiled cadavers has not yet been demonstrated. Aims and Objectives: The main objective of this study was to test whether we can infer PMI of boiled cadavers based on the succession of microbial communities. Materials and Methods: SD rats were killed by cervical dislocation. Subsequently, the rat cadavers were divided into the case (boiled cadavers) and control (unboiled cadavers) groups. Rectal samples were collected from the rats for 45 days and at nine time points. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial community in the rectum. Results: The results showed that the composition and relative abundance of bacterial communities at the phylum level were significantly different between the case and control groups. The alpha diversity of the microbial community showed a decreasing trend with the decomposition process. Principal coordinate analysis showed that the case and control groups had obvious patterns along the succession of microbial communities. The rectal microbial communities showed a significant linear trend in the time course of decomposition. A random forest model was used to infer PMI. The goodness-of-fit (R2) of the model was 68.00% and 84.00%, and the mean absolute errors were 2.05 and 1.48 days within 45 days of decomposition for the case and control groups, respectively. Conclusions: Our results suggest that microbial community succession could be a potential method to infer PMI of boiled cadavers.

Antibiotic Sensitivity of Group B Streptococcus from Pregnant Mothers and Its Association with Resistance Genes

Objective: This study assessed the antibiotic susceptibility and characterized antibiotic resistance genes of group B Streptococcus (GBS) isolates from selected tertiary care hospitals in Western Province, Sri Lanka. Methods: A descriptive cross-sectional study was carried out to determine antibiotic sensitivity of GBS among 175 pregnant women of >35 weeks of gestation attending antenatal clinics in four teaching hospitals. Low vaginal and rectal swabs were collected separately, and GBS was identified by standard microbiological methods. Antibiotic sensitivity and minimum inhibitory concentration (MIC) were performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. DNA was extracted from culture isolates, and antibiotic-resistant genes were identified by polymerase chain reaction using ermB, ermTR, mefA, and linB genes. Results: GBS colonization in the study sample was 25.7% (45/175) with detection rate of 22.9% (40/175) and 2.9% (5/175) in vaginal and rectal samples, respectively. All isolates were susceptible to penicillin with an MIC range of 0.03–0.12 μg/mL. Six isolates (13.3%) were intermediate, and 11 isolates (24.4%) were resistant to erythromycin. There were 5 intermediately resistant isolates (11.1%) and 10 resistant isolates (22.2%) for clindamycin. Of them, seven had inducible clindamycin resistance (iMLS_B). MIC range of erythromycin was 0.03–0.32 μg/mL and that of clindamycin was 0.06–0.32 μg/mL. ermB gene was detected in 7 (15.5%). ermTR gene was found in 16 (35.6%) and was significantly associated with iMLS_B phenotype (p = 0.005). mefA gene was detected in two (4.4%) isolates, while linB gene was not detected in tested isolates. Conclusion: All isolates were sensitive to penicillin, and the most prevalent resistance genotype was ermTR in the study population.

Understanding the Role of Cancer Stem Cells in Treatment Resistance and Poor Outcomes of Rectal Cancer in Indian Population

Background Rectal cancer is one of the common gastrointestinal cancers and a leading cause for cancer deaths in India especially in the younger population. Cancer stem cells as part of intratumoral heterogeneity are attributed to therapy failure due to stemness related resistance mechanisms. Better understanding of resistant stem cell clones of rectal cancer will increase the success rate of cancer treatment. Methods After Institutional ethical committee approval the primary cell cultures from two tumour specimens of rectal cancer patients planned for chemoradiation and at the time of surgery were prepared. From single cell suspension cultures total stem cell population was estimated based upon Hoechst 33342 dye staining technique and its correlation with patientsrsquo overall survival was evaluated.Results During the study period out of 91 newly diagnosed rectal cancer patients 21 rectal cancer tissue samples were collected before chemoradiation and at the time of surgery from 12 patients consisting of ten males and two females in the age range of 29 to 67 years. Single cell suspension culture from tumour tissue samples collected from eight patients prior to their chemoradiation were prepared with maximum duration of viability of 10 days. Range of percentage of Hoechst low stem cells to Hoechst bright tumours cells was from 0.2 to 0.9 in eight SCSC with significant correlation with overall survival.Conclusion Cancer stem cell populations in rectal cancer patients can be attributed to poor outcomes owing to the resistance mechanisms to chemoradiation termed as stemness. Better understanding of stemness and targeting of pathways by novel therapies can improve current poor outcome.

Изменение экспрессии мРНК панели генов в слизистой оболочке толстой кишки в процессе естественного старения

Background: during natural aging, cellular and molecular changes in the colonic mucosa contribute to chronic damage and the development of various neoplasia, including colorectal cancer (CRC). Aim: to assess the age peculiarities of mRNA expression in samples of normal mucosa from various parts of the colon. Patients and Methods: the study included 95 patients. Normal colonic mucosa biopsies were derived during videocolonoscopy from different parts of the colon, i.e., the right colon (n=91), left colon (n=95), and rectum (n=87). In total, 273 samples were examined. The relative level of mRNA expression of 63 genes potentially involved in various pathways of CRC carcino-genesis was evaluated by reverse transcription polymerase chain reaction. Results: a linear regression model for predicting passport age, including data on gene ex-pression, was characterized by moderate reliability (R2 0.45, DW test 1.54). Age estimation er-rors in the model arise proportionally to its increase, which is associated with the accumulation of epigenetic changes. Maximum accuracy in age prediction is typical for rectal mucosa samples. The first statistically significant division (primary classification node) of patients by age in indi-viduals over or under 60 years provides the level of TERT gene expression. Telomerase activity in association with HLA-G5 gene overexpression is typical in older patients, whereas HLA-G5 gene hypoexpression and simultaneous granulysin (GNLY) overexpression are typical in patients younger than 60 years. A molecular cascade involving a decrease in telomerase activity due to TERT hypoexpression with simultaneous overexpression of the cell cycle regulator and tumor suppressor P14ARF is also typical for normal colonic mucosa in patients aged 60 years and over. Conclusion: our findings support molecular genetic changes in the colonic mucosa that occur with age. The specifics of gene expression involved in CRC carcinogenesis are the basis for assessing CRC risk. KEYWORDS: gene expression, mRNA, RT-PCR, normal colon mucosa, age, epigenetic changes, colorectal cancer. FOR CITATION: Goncharov S.V., Bozhenko V.K., Zakharenko M.V., Chaptykov A.A., Kulinich T.M., Solodkiy V.A. Changes in mRNA expression of colon mucosa genes during natural aging. Russian Medical Inquiry. 2023;7(6):347–352 (in Russ.). DOI: 10.32364/2587-6821-2023-7-6-2.

Assessment of Microbial Load and Multidrug-Resistant Profile of Bacterial Flora from Cattle in Bauchi, Nigeria

Aim: The study aimed to assess the bacterial load of in rectal swabs from cattle by isolating Enterococcus spp and Escherichia coli, and determining the multidrug-resistant pattern of the isolates.
 Study Design: The study is a clinical-veterinary laboratory investigation involving the isolation and determination of the multidrug-resistant (MDR) profile of Enterococcus spp and E. coli isolated from cattle rectal.
 Place and Duration of Study: This study was carried out in the Yelwa and Gubi campuses Farm centers of Abubakar Tafawa Balewa University (ATBU), Bauchi, Nigeria, in period extended from April to June 2021.
 Methodology: Fresh rectal swab samples were collected from the randomly selected cattle and labeled. The samples were immediately transported and processed in the Microbiology laboratory at Yelwa Campus, and the bacterial load of each sample was determined using standard techniques. Enterococcus spp and E. coli were isolated using differential culture media followed by an appropriate biochemical identification test. The isolates were subjected to the Kirby-Bauer disc diffusion method, to assess the antimicrobial susceptibility pattern.
 Results: In Yelwa, the highest microbial load is 2.7 x 1012 CFU/g. while the lowest microbial load is 2.0 x 1012 CFU/g. In the Gubi campus, the highest microbial load is 3.4 x 1012 CFU/g. while the lowest microbial load is 2.7 x 1012 CFU/g. Both in Yelwa and Gubi ,the result showed that most isolates of Enterococcus spp and E. coli are multidrug-resistant. In Yalwa some of the isolates showed 100% resistance against Norfloxacin, Rifampicin, Ampicillin, and Streptomycin, while Gentamycin gave the lowest multidrug resistance (57.4%). In Gubi, the highest was to ampicillin with (90.6%) frequency, while the lowest resistance was found in Chloramphenicol (11.3%). In Yelwa, a high percentage resistance (92.6%) was observed in Streptomycin, and Cephalexin has the lowest (20.4%). In Gubi, all the E. coli isolates had 100% resistance against sulfamethoxazole, and the lowest was in Ofloxacin (43.4%).
 Conclusion: This study found that cattle in the area are reservoirs of bacteria that are both part of the normal flora and opportunistic pathogens, and harbored resistance phenotypes. It is therefore advocated that the use of these animals’ faeces as manure should be done with caution, particularly after pre-treatments.

One-Year Surveillance of SARS-CoV-2 Exposure in Stray Cats and Kennel Dogs from Northeastern Italy.

Dogs and cats are susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). During the pandemic, several studies have been performed on owned cats and dogs, whereas limited data are available on the exposure to stray animals. The objective of this study was to investigate the exposure to SARS-CoV-2 of feral cats and kennel dogs in northeastern Italy, through serological and molecular methods. From May 2021 to September 2022, public health veterinary services collected serum, oropharyngeal, and rectal swab samples from 257 free-roaming dogs newly introduced to shelters, and from 389 feral cats examined during the routinely trap-neutered-return programs. The swabs were analyzed for viral RNA through a real-time reverse transcriptase PCR (rRT-PCR), and sera were tested for the presence of the specific antibody against SARS-CoV-2 (enzyme-linked immunosorbent assay). Serology was positive in nine dogs (9/257) and three cats (3/389), while two asymptomatic cats tested positive to rRT-PCR. One cat turned out to be positive both for serology and molecular analysis. In addition, this study described the case of a possible human-to-animal SARS-CoV-2 transmission in a cat that travelled in close contact to a COVID-19-positive refugee from Ukraine. This study shows that SARS-CoV-2 can infect, in natural conditions, stray cats and kennel dogs in northeastern Italy, although with a low prevalence.

To β or Not to β: Lack of Correlation Between APC Mutation and β-Catenin Nuclear Localization in Colorectal Cancer.

Colorectal cancer (CRC) appears to arise from sequential genetic lesions in tumor suppressor genes (APC, SMAD4, and TP53) and oncogenes (KRAS) leading to the classical adenoma to carcinoma progression. Biallelic APC inactivating genetic aberrations are detected in about 70% of early microadenomas implicating APC inactivation as the first genetic hit in CRC. APC is an essential protein of the Wnt 'destruction complex'; APC inactivation is believed to cause disruption of the complex allowing stabilization and nuclear translocation of β-catenin, resulting in transcriptional activation of cancer-promoting genes. β-catenin nuclear localization and APC mutation were validated from serial FFPE sections representing the same tumor regions, using immunohistochemistry and Sanger sequencing, respectively. Here, we provide evidence for a surprising lack of correlation between APC mutation and β-catenin nuclear localization in early-onset sporadic rectal cancer samples. Several factors including status of KRAS mutation could not explain this anomaly. The lack of correlation was validated in CRC cell lines harboring various APC mutations. Our results provide evidence directly from tumor samples for possible non-canonical role(s) for mutant APC.

Rapid molecular detection and isolation of canine distemper virus in naturally infected dogs

The canine distemper virus (CDV), which infects dogs and a broad range of animal species, remains a serious concern in Türkiye and across the world. The current study shows that CDV can be detected and isolated rapidly and specifically in naturally infected dogs. Whole blood, nasal swab, ocular swab, rectal swab, and urine samples from 50 stray dogs were used in the study (n = 250). The presence of the CDV genome was confirmed in 105 (42%) samples using one-Step real-time RT-PCR. In total, 39 dogs were diagnosed with CDV infection based on the detection of cytopathic effects in MDCK, which was verified by the fluorescent antibody technique. A total of 12 one-Step real-time RT-PCR negative samples, consisting of 4 rectal swabs and 8 urine samples, were found to be positive by virus isolation. Blood, nasal swab, ocular swab (P<0.01, r = 1), rectal swab (P<0.01, r = 0.844), and urine samples (P<0.01, r = 0.697) all showed positive correlations in the tests for viral genome detection and virus isolation. CPE levels of high 37 (31.62%), medium 26 (22.23%) and low 54 (46.15%) were detected in a total of 117 (46.8%) samples with viral growth in cell culture. The highest CPE levels detected by FAT were for rectal swab and urine samples. In conclusion, the one-step real-time RT-PCR method on rectal swab samples proved to be a very sensitive method for the rapid and reliable CDV detection. Besides, non-modified MDCK can be used to isolate CDV from naturally infected dogs.

Presence of Coliforms in Water, Poultry Mouth and Rectal Swabs from Selected Smallholder Poultry Farming Projects of Capricorn District, South Africa

Background: Limited biosecurity measures in smallholder poultry facilities expose birds to various pathogens as a result, poultry products particularly raw ones are reported to be responsible for cases of human foodborne diseases. The aim of the study was to profile and characterise the zoonotic bacterial pathogens in water, poultry mouth and rectal swabs in a value chain project of Capricorn district, Limpopo Province, South Africa. Methods: A total of 74 samples comprising of 14 water samples, 60 mouth and rectal swab samples were collected from the farms. The samples were screened for the presence of Escherichia coli, Salmonella spp. and Shigella spp. through selective cultivation. Result: The study revealed that the water resources, mouth and rectal swab samples of chickens were contaminated by coliform bacteria. Escherichia coli and Klebsiella spp., were dominant isolates. E. coli strains that were isolated from the water sources, mouth and rectal swabs of the chickens showed strong resistance to gentamycin, neomycin, penicillin, streptomycin, tetracycline, erythromycin, nalidixic acid, ciprofloxacin and ampicillin. K. pneumoniae showed resistant to neomycin; penicillin; erythromycin while K. oxytoca and E. absuriae showed similar antibiotic resistance profile as penicillin, erythromycin, nalidixic acid and ampicillin.

Determination Of Enterococcus Species And Antibiotic Resistance In Budgerigars

Abstract: In this study, it was aimed to determine the resistance profile by examining the prevalence and species distribution of enterococci in rectal samples of healthy budgerigars and their susceptibility to antibiotics. 100 cloacal swab samples were used in the study. Identification and antibiotic resistance of Enterococcal isolates obtained by classical methods were determined with the automated identification system. As a result of the study, 22 (75.86%) E. faecalis, 2 (6.90%) E. faecium (6.90%) E. hirae (6.90%) and E. casseliflavus/gallinarum and 1 S. uberis (3.44%) was obtained. The presence of Enterococci was detected in 29% of the samples. In general, they were suspectible to Amoxicillin clavunate (96.4%), Ampicillin (100%), Ciproflaxacin (54.2%), Levoflaxacin (60.9%), Gentamicin(Syn) (82.1%), Streptomycin(Syn) (28.6%), Tigecycline (80%), Vancomycin(89.3%), Teicoplanin (96.4%), Linezolide (96.4%) and Nitrofurontion (100%), and they showed 100% resistance to Cefocitin, Amikacin, Gentamicin, Tobramycin, Clindamycin, Erythromycin, TMP-SXT, Fusidic acid and Quinopuristin-Dalfopuristin. The presence of Entrococcal species, which are very important in terms of zoonosis, in healthy budgerigars was revealed. In addition, the different types of antibiotic resistance found in the studies also reveal the necessity of performing antibiotic susceptibility tests in this type of infections. However, it has been demonstrated that which antibiotics will be effective in nosocomial and/or gastrointestinal infections of Enterococcal origin in budgerigars.

ABX464 (Obefazimod) Upregulates miR-124 to Reduce Proinflammatory Markers in Inflammatory Bowel Diseases.

Advanced therapies have transformed the treatment of inflammatory bowel disease; however, many patients fail to respond, highlighting the need for therapies tailored to the underlying cell and molecular disease drivers. The first-in-class oral molecule ABX464 (obefazimod), which selectively upregulates miR-124, has demonstrated its ability to be a well-tolerated treatment with rapid and sustained efficacy in patients with ulcerative colitis (UC). Here, we provide evidence that ABX464 affects the immune system in vitro , in the murine model of inflammatory bowel disease, and in patients with UC. In vitro , ABX464 treatment upregulated miR-124 and led to decreases in proinflammatory cytokines including interleukin (IL) 17 and IL6, and in the chemokine CCL2. Consistently, miR-124 expression was upregulated in the rectal biopsies and blood samples of patients with UC, and a parallel reduction in Th17 cells and IL17a levels was observed in serum samples. In a mouse model of induced intestinal inflammation with dextran sulfate sodium, ABX464 reversed the increases in multiple proinflammatory cytokines in the colon and the upregulation of IL17a secretion in the mesenteric lymph nodes. By upregulating miR-124, ABX464 acts as "a physiological brake" of inflammation, which may explain the efficacy of ABX464 with a favorable tolerability and safety profile in patients with UC.

Post-irradiation intratumoral heterogeneity modulates response to immune checkpoint inhibition therapy in a murine melanoma model

PurposeThe underlying mechanism for radiation as a potentiator of immune checkpoint inhibition (ICI) is unclear. We developed a novel murine model to investigate the effects of post-irradiation intratumoral heterogeneity (ITH) on response to ICI. Experimental designParental mouse melanoma B16F10 cells were irradiated in vitro (5Gy x 3 fractions), then an a priori determined number of resulting colonies were implanted in C57BL/6J immunocompetent mice creating syngeneic models of unirradiated (parental) and irradiated tumors with low (irradiated-L) and high (irradiated-H) ITH. Mice were treated with placebo, α-PD-L1, α-CTLA-4 or dual ICI. Murine tumors underwent whole exome sequencing (WES). Clinically correlated paired pre- and post-irradiation patient rectal adenocarcinoma samples underwent WES. ResultsIrradiated-L tumors showed increased tumor mutational burden (TMB) and a sustained decrease in ITH. Irradiated-L tumors were predicted to express five neoantigens with high variant allele frequency/clonal distribution. Mice with irradiated-L and irradiated-H versus parental B16F10 tumors demonstrated longer overall survival with dual ICI. Only mice with irradiated-L tumors experienced an overall survival benefit with single agent ICI. Clinically correlated rectal adenocarcinoma samples showed similarly increased TMB and decreased ITH following irradiation. ConclusionsPost-irradiation ITH modulates ICI response in a murine melanoma model. Irradiation may offer a mechanism to widen the therapeutic window of ICI.

The bacteria of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) are site-specific and distinct from freshwater environment.

Bacteria play an essential role in the health of marine mammals, and the bacteria of marine mammals are widely concerned, but less is known about freshwater mammals. In this study, we investigated the bacteria of various body sites of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) and analyzed their association with freshwater environmental bacteria. The bacterial community and function of Yangtze finless porpoise showed apparent site-specificity. Various body sites have distinct differences in bacteria and have their dominant bacteria. Romboutsia, Plesiomonas, Actinobacillus, Candidatus Arthromitus dominated in the intestine (fecal and rectal samples). Fusobacterium, Streptococcus, and Acinetobacter dominated in the oral. The dominant genera in the blowhole include Suttonella, Psychrobacter, and two uncultured genera. Psychrobacter, Flavobacterium, and Acinetobacter were dominant in the skin. The alpha diversity of intestinal (fecal and rectal) bacteria was the lowest, while that of skin was the highest. The oral and skin bacteria of Yangtze finless porpoise significantly differed between the natural and semi-natural conditions, but no sex difference was observed. A clear boundary was found between the animal and the freshwater environmental bacteria. Even the skin bacteria, which are more affected by the environment, are significantly different from the environmental bacteria and harbor indigenous bacteria. Our results provide a comprehensive preliminary exploration of the bacteria of Yangtze finless porpoise and its association with bacteria in the freshwater environment.

Ocular Rosacea microBiome Study (ORBS)—sub-microbial versus antibiotic dosing of doxycycline versus placebo in treatment of symptomatic ocular rosacea: study protocol for a parallel-arm randomized clinical trial

BackgroundOcular rosacea is common and is often managed with long-term antibiotic treatment. Doxycycline is the most commonly selected antibiotic for the treatment of rosacea. As there is no established standard of care treatment dose for rosacea, prescribed doses of doxycycline vary widely. The FDA classifies 40 mg daily dose of doxycycline for ocular rosacea as sub-microbial in comparison to an antibiotic dose of 200 mg daily. However, this “sub-microbial” dose has never been evaluated in patients with ocular rosacea, and even the sub-microbial dose has potential to alter systemic mucosa flora. Here, we present a randomized controlled trial using RNA sequencing to fully characterize the impact of sub-microbial antibiotic dosing of doxycycline on antimicrobial resistance and bacterial composition of the ocular and gut flora.MethodsIn a triple-masked parallel randomized control trial, patients with ocular rosacea will be randomized to three arms: a 40-mg dose of doxycycline, a 200-mg antibiotic dose of doxycycline, or placebo. Collected rectal and lower eyelid samples will be compared for frequency of antimicrobial resistance genetic determinants and microbiome diversity. A subjective ocular surface disease index survey and objective tear breakup time measurement will be determined.DiscussionThese results will enhance our understanding of the overall systemic impact of long-term systemic sub-microbial antibiotic dosing for the treatment of chronic recurrent ocular inflammatory diseases.Trial registrationThis trial was registered on ClinicalTrials.org (NCT05296837) on March 22, 2022.

14. Monkeypox viral detection from different body sites. Northern California, June–July 2022

Abstract Background Unlike prior outbreaks of monkeypox, the 2022 outbreak is unique because lesions have been predominantly noted in the anogenital area, especially among persons identifying as gay, bisexual, or other men who have sex with men. The role of various body sites in monkeypox transmission is currently unclear. We assessed monkeypox PCR positivity from various body sites. Methods We collected demographic, clinical, and laboratory data from patients with confirmed monkeypox at Stanford during June–July 2022. We obtained samples from skin lesions, oropharynx, saliva, conjunctiva, urine, semen, and rectum. Monkeypox DNA analysis was performed on site using a quantitative PCR modified from published CDC assays. Results During June–July 2022, 10 patients were confirmed to have monkeypox. All were men; median age was 40 (range 24–46). Four patients identified as Hispanic, three as Caucasian, two as African American, and one as Asian. Additionally, three had HIV infection and the remaining seven were on HIV pre-exposure prophylaxis. At the time of diagnosis, eight patients (80%) described a prodrome of fever and malaise. Seven (70%) had genital lesions; the remaining three (30%) presented with only extra-genital lesions. Complications included two patients with proctitis (20%), one with phimosis (10%) and one with tonsillar involvement and impending airway compromise (10%). A total of seven (70%) received tecovirimat, and one was hospitalized. Median time from symptom onset to sample collection was seven days (range 3–14). All patients had at least one skin lesion sample positive for monkeypox virus DNA (Table 1). Six rectal samples (100%), Eight oropharyngeal samples (89%) and two (66%) urine samples were also positive. Conclusion We found monkeypox PCR positivity from different body sites. Public health messaging should consider targeting behaviors that involve body sites beyond skin, with particular consideration to mucosal surfaces. Disclosures All Authors: No reported disclosures.

421. In vitro and in vivo synergistic antimicrobial activities of the combinations of meropenem, colistin, tigecycline, and ceftolozane/tazobactam against carbapenem-resistant Klebsiella pneumoniae

Abstract Background The aim of this study was to evaluate the in vitro and in vivo activities of various antimicrobial combinations against carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods The in vitro activity of six two-drug combinations against CRKP isolates collected from the rectal swab samples of patients with intestinal CRKP colonization was evaluated using the checkerboard method and time-kill assay to identify potential synergistic and bactericidal two-drug combinations against CRKP isolates. The in vivo efficacy of the combinations of colistin, meropenem and ceftolozane/tazobactam (C/T) as therapeutic options, was assessed in a mouse model of intraperitoneal CRKP sepsis. Antimicrobial susceptibility and genotypes of carbapenem-resistance were also analyzed. Results A total of 5 clinical isolates of CRKP were collected from nonduplicate patients with CRKP infection. Of 5 CRKP isolates, 4 carried the blaKPC-2-type carbapenem-hydrolyzing enzymes except 1 blaNDM-1-type. Antimicrobial susceptibility rates were tigecycline 80%, colistin 40%, and C/T 0%, respectively. The checkerboard assay showed that in vitro synergistic activity against CRKP isolates was 90% for the meropenem-tigecycline combinations and 20% for colistin-C/T combinations. None of the various combinations of the six antibiotics showed a synergistic effect in the time-kill assay. However, the meropenem-colistin (100%) and colistin-C/T (100%) combinations showed bactericidal effects in the time-kill assay (using an antibiotic concentration of 1× MIC) (Table). The survival rates of the mice was 80% (4/5) at 48 h in the treated group using low dose combinations of colistin (10 mg/kg) and C/T (25 mg/kg), unlike both antibiotics, which were 60% in a monotherapy with the same dose (Figure). Comparison of checkerboard assay and time-kill assay Comparison of checkerboard assay and time-kill assay associated with the bactericidal activity of two-drug combinations (1 × MIC) against each carbapenem-resistant Klebsiella pneumoniae isolate In vivo survival tests for antimicrobial combinations Comparison of the survival rates of the mice in the treated group using antimicrobial combinations Conclusion In conclusion, the present in vivo study demonstrated that the low-dose combination of colistin and C/T may be a promising alternative to nephrotoxic high-dose colistin alone for treating CRKP infections. However, it was difficult to predict this possibility in in vitro tests, and even there is great discordance of antimicrobial synergistic activities between the checkerboard microdilution and time-kill assays. Disclosures All Authors: No reported disclosures.

Retrospective Evaluation of the Most Frequently Observed Histological Changes in Duodenal and Rectal Mucosal Biopsies in Horses with Recurrent Colic.

Colic, a condition affecting the gastrointestinal tract of horses, manifests as severe pain and may be a life-threatening condition. It is possible to distinguish between an acute, disposable process, as well as recurrent colic symptoms (abdominal pain) caused by an ongoing chronic inflammatory process. This paper presents a retrospective analysis of the histopathological findings of duodenal and rectal samples taken from horses with recurrent colic, with the aim to determine the frequency and extent of inflammation. The samples, i.e., duodenal biopsy (60 samples) and rectal biopsy (17 samples), were taken from 77 horses showing recurrent colic symptoms. Histopathological examination included staining with hematoxylin and eosin. The examination included evaluation of the superficial epithelium, mucosal lamina propria, and submucosa. All samples from the duodenum and rectum showed the presence of leukocyte infiltration in the mucosal lamina propria. The most frequently observed cellular infiltration was a moderate infiltration consisting of lymphocytes and plasma cells in duodenum and mixed populations of plasma cells, lymphocytes, and eosinophilia in the rectum. Mott cells were also noted among the inflammatory infiltrates. More than one-fourth of the horses were found to have shortened intestinal villi. The results presented here showed the involvement of inflammation in the course of recurrent colic, which can be both its cause (by impairing motility and absorption) and its effect (as a result of obstruction or ischemia).

Prevalence of bat viruses associated with land-use change in the Atlantic Forest, Brazil.

Bats are critical to maintaining healthy ecosystems and many species are threatened primarily due to global habitat loss. Bats are also important hosts of a range of viruses, several of which have had significant impacts on global public health. The emergence of these viruses has been associated with land-use change and decreased host species richness. Yet, few studies have assessed how bat communities and the viruses they host alter with land-use change, particularly in highly biodiverse sites. In this study, we investigate the effects of deforestation on bat host species richness and diversity, and viral prevalence and richness across five forested sites and three nearby deforested sites in the interior Atlantic Forest of southern Brazil. Nested-PCR and qPCR were used to amplify and detect viral genetic sequence from six viral families (corona-, adeno-, herpes-, hanta-, paramyxo-, and astro-viridae) in 944 blood, saliva and rectal samples collected from 335 bats. We found that deforested sites had a less diverse bat community than forested sites, but higher viral prevalence and richness after controlling for confounding factors. Viral detection was more likely in juvenile males located in deforested sites. Interestingly, we also found a significant effect of host bat species on viral prevalence indicating that viral taxa were detected more frequently in some species than others. In particular, viruses from the Coronaviridae family were detected more frequently in generalist species compared to specialist species. Our findings suggest that deforestation may drive changes in the ecosystem which reduce bat host diversity while increasing the abundance of generalist species which host a wider range of viruses.