High Frequency and Diversity of Tetracycline Resistance Genes in the Microbiota of Broiler Chickens in Tunisia

Tetracycline resistance is still considered one of the most abundant antibiotic resistances among pathogenic and commensal microorganisms. The aim of this study was to evaluate the prevalence of tetracycline resistance (tet) genes in broiler chickens in Tunisia, and this was done by PCR. Individual cloacal swabs from 195 broiler chickens were collected at two slaughterhouses in the governorate of Ben Arous (Grand Tunis, Tunisia). Chickens were from 7 farms and belonged to 13 lots consisting of 15 animals randomly selected. DNA was extracted and tested for 14 tet genes. All the lots examined were positive for at least 9 tet genes, with an average number of 11 tet genes per lot. Of the 195 animals tested, 194 (99%) were positive for one or more tet genes. Tet(L), tet(M) and tet(O) genes were found in 98% of the samples, followed by tet(A) in 90.2%, tet(K) in 88.7% and tet(Q) in 80%. These results confirm the antimicrobial resistance impact in the Tunisian poultry sector and suggest the urgent need to establish a robust national antimicrobial resistance monitoring plan. Furthermore, the molecular detection of antibiotic resistance genes directly in biological samples seems to be a useful means for epidemiological investigations of the spread of resistance determinants.

Comprehensive Analysis of DNA Methylation Regulator DNA Methyltransferase (DNMT) Family and Ten-Eleven-Translocation (TET) Enzymes Family in Pan-Cancer

Background: DNA methyltransferase (DNMT) family and ten-eleven-translocation (TET) family enzymes play pivotal roles in regulating DNA methylation, and are closely related to diverse cancers. This study was designed to clarify the specific roles of DNMT and TET genes in pan-cancers.Methods: The expression, mutation, copy number variations (CNVs), cancer-related pathways, immune cell infiltration correlation, and prognostic potential of DNMT/TET genes were systematically investigated in 33 cancer types using next-generation sequence data from the Cancer Genome Atlas database. Results: DNMT3B was more highly expressed in the majority of tumors analyzed than in normal tissues. Most DNMT/TET genes were frequently mutated in uterine carcinosarcoma, and TET1 and TET2 showed higher mutation frequencies in various cancer types. DNMT3B exhibited inclusive copy number amplification in almost all cancers, such as stomach adenocarcinoma(STAD) and colon adenocarcinoma(COAD)l, while most DNMT/TET genes displayed highly copy number deletion in kidney chromophobe（KICH）. DNMT/TET genes were mainly involved in the following cancer-related pathways: UV response DN, mitotic spindle, cholesterol homeostasis, TGF beat signaling, xenobiotic metabolism, G2/M checkpoint, and E2F targets. DNMT/TET genes were significantly correlated with NK cells, CD4 positive T cells, and Tfh cells. Additionally, Most DNMT/TET genes were significantly associated with lower survival rates of adrenocortical carcinoma (ACC), mesothelioma, and liver hepatocellular carcinoma (LIHC), but played a protective role in thymoma (THYM). Furthermore, overexpression of most DNMT genes, except for DMAP1, was associated worse prognoses in pan-cancer. Conclusion: These results suggest that DNMT/TET genes can serve as potential predictors for prognosis and treatment in pan-cancer, providing new insight for future study.

Tetracycline Resistant Genes as Bioindicators of Water Pollution

The current study aimed to investigate the prevalence of tetracycline resistant bacteria isolated from different water samples and the genes responsible for this resistance. Two hundred fifty isolates were isolated from different water samples from two different locations. Isolates were obtained from El-Zamalek site was (n =110) and from Rod El-Farag site was (n = 140). A hundred isolates out of 250 bacterial isolates (40%) were resistant to tetracycline at a concentration of 16 μg/ml. Only 31 (31%) were selected due to their resistance to (32 μg/ml) tetracycline for identification. All selected isolates were identified according to biochemical and the 16S sequence techniques. The 16S rDNA gene sequences of the bacterial isolates which were reported in this study were submitted to the NCBI database. Of the 31 isolates were analyzed by Polymerase Chain Reaction (PCR), results showed that 41.9 % (13/31) harbored tet A gene, 74.2% (23/31) carried tet D gene, while 12.9 % (4/31) carried tet M gene. Whereas tet B, tet C and tet O were not detected. Twenty-one isolates (67.7%) harbored a single tet gene, five isolates (16.1%) harbored two different tet genes while three isolates (9.7 %) harbored three different tet genes. Moreover, two isolates were free from any tested tet genes.

1377. Omadacycline In Vitro Activity Against a Molecularly Characterized Collection of Clinical Isolates with Known Tetracycline Resistance Mechanisms

Background Omadacycline is a novel aminomethylcycline that recently completed Phase 3 clinical trials for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) and community-acquired bacterial pneumonia (CABP). This study evaluated the activity of omadacycline against a broad collection of recent (2016) clinical isolates with molecularly characterized tetracycline resistance mechanisms. Methods A total of 177 Gram-positive and -negative clinical isolates were identified as carrying acquired tetracycline resistance genes and were included in this study. Isolates were previously subjected to next-generation sequencing followed by screening of known tetracycline resistance mechanisms. Susceptibility testing and interpretation were performed according to CLSI methods. Results Omadacycline demonstrated MIC50 values of 0.06–0.12 µg/mL against Gram-positive isolates carrying tet genes. Similar MIC results (0.06–0.12 µg/mL) were obtained against Gram-positive organisms carrying tet(K), tet(L)/tet(M) or tet(M). Omadacycline (MIC50/90, 0.12/0.25 µg/mL) and tigecycline (MIC50/90, 0.06/0.25 µg/mL) showed similar MIC results when tested against Staphylococcus aureus carrying tet(K). While tetracycline was less active (0.0–78.6% susceptible) against Tet(K)-producing S. aureus, doxycycline (MIC50/90, 0.5/0.5 µg/mL; 100.0% susceptible) was active in vitro. Omadacycline (MIC90, 0.25–2 µg/mL) and tigecycline (MIC90, 0.12–1 µg/mL) showed potent MIC results against Gram-positive isolates carrying tet(L) and/or tet(M). Tetracycline and doxycycline had MIC90 values of ≥8 µg/mL. Omadacycline (MIC90 4–32 µg/mL) and tigecycline (MIC90 0.5–2 µg/mL) were active against Gram-negative isolates harboring tet(A), tet(B) or tet(D) or a combination of tet. Tetracycline (MIC50/90, >16/>16 µg/mL) and doxycycline (MIC50/90, >8/>8 µg/mL) had elevated MIC50 and MIC90 results against these isolates. Conclusion Results presented here indicate that omadacycline is not adversely affected by tet genes present in contemporary Gram-positive and -negative clinical isolates, a characteristic that differs from the legacy tetracycline agents. Disclosures R. E. Mendes, Paratek Pharmaceuticals: Research Contractor, Research support. M. Castanheira, Paratek Pharmaceuticals: Research Contractor, Research support. E. S. Armstrong, Paratek Pharmaceuticals: Employee, Salary. J. N. Steenbergen, Paratek Pharmaceuticals: Employee and Shareholder, Salary. R. K. Flamm, Paratek Pharmaceuticals: Research Contractor, Research support.

Differential expression of ten-eleven translocation genes in endometrial cancers

Ten-eleven translocation proteins are α-ketoglutarate-dependent dioxygenases involved in the conversion of 5-methylcytosines (5-mC) to 5-hydroxymethylcytosine (5-hmC), 5-formylcytosine, and 5-carboxylcytosine that play a significant role in DNA demethylation. Deregulation of TET genes expression and changes in the level of 5-hmC are thought to be associated with the onset and progression of several types of cancer, but there are no such data related to endometrial cancer. The aim of the work was to investigate the messenger RNA expression levels of TET1, TET2, and TET3 in relation to clinicopathological characteristics of endometrial cancer as well as the correlation between expression of TET genes and the level of 5-hmC/5-mC. The prognostic significance of TETs expression for overall survival was established. We found that TET1 and TET2 messenger RNA expression was lower and TET3 was higher in cancers compared to normal tissues. Positive correlation between 5-hmC and the relative expression of TET1 and TET2 was found, but no correlation was observed in the case of TET3. Decreased expression of TET1 and TET2 was significantly associated with increased lymph node metastasis and International Federation of Gynecology and Obstetrics stage. Kaplan–Meier analysis indicated that low TET1 expression predicted poor overall survival (p = 0.038). Multivariate analysis identified the TET1 expression in endometrial cancer as an independent prognostic factor. Our results suggest that decreased expression of TET1 correlates with tumor progression and may serve as a potential prognostic biomarker in endometrial cancer.