The RND Efflux Pump Gene Expression in the Biofilm Formation of Acinetobacter baumannii.

Multidrug resistant (MDR) Acinetobacter baumannii is a critical opportunistic pathogen in healthcare-associated infections (HAI). This is attributed to several factors, including its ability to develop biofilms that can enhance antimicrobial resistance (AMR) in addition to creating an environment for horizontal transfer of antibiotic resistance genes. The role of the efflux pump in biofilm formation is important for studies on alternative treatments for biofilms. One of the significant efflux pump families is the RND efflux pump family, which is common in Gram negative bacteria. The aim is to study the role of the RND efflux pump in biofilm formation by A. baumannii. The biofilm formation potential of thirty-four MDR A. baumannii isolates was evaluated by crystal violet assays. The effect of efflux pump inhibition and activation was studied using the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and the RND efflux pump substrate levofloxacin (at sub-MIC), respectively. The isolates were genotypically grouped by enterobacterial repetitive intergenic consensus (ERIC) typing and the expression of adeABC, adeFGH, and adeIJK efflux pump genes was measured by qPCR. Overall, 88.2% (30/34) of isolates were biofilm producers (the phenotype was variable including strong and weak producers). Efflux pump inhibition by CCCP reduced the biofilm formation significantly (p < 0.05) in 17.6% (6/34) of some isolates, whereas sub-MICs of the substrate levofloxacin increased biofilm formation in 20.5% (7/34) of other isolates. Overexpression of the three RND efflux pump genes was detected in five out of eleven selected isolates for qPCR with remarkable overexpression in the adeJ gene. No correlation was detected between the biofilm phenotype pattern and the RND efflux pump gene expression in biofilm cells relative to planktonic cells. In conclusion, the role of the RND efflux pumps AdeABC, AdeFGH, and AdeIJK in biofilm formation does not appear to be pivotal and the expression differs according to the genetic background of each strain. Thus, these pumps may not be a promising target for biofilm inhibition.

Crimean-Congo hemorrhagic fever virus in ticks collected from imported camels in Egypt.

Crimean-Congo hemorrhagic fever (CCHF) is one of the utmost broadly distributed tick-borne viruses, with an infection resulting in a fatality rate of up to 30%. During this study period, 25,000 hard adult ticks of Hyalomma species were collected from freshly slaughtered imported camels to determine the presence of Crimean-Congo hemorrhagic fever virus (CCHFV) and genetic lineage of the virus. Ticks were pooled and analyzed for the existence of CCHFV using nested RT- PCR and real-time reverse transcription PCR; the genome was detected in 18 (1.44%) tick pools. Partial genome sequences reveal an adjacent relationship with strains from South Africa to Namibia, Nigeria, Sudan, Senegal, and Mauritania, corresponding to the Africa I and III genotypes. This study indicates the presence of CCHFV in Egypt and illustrates the potential for tick-borne dissemination of the virus. Further studies focused on not only tick samples, but also human samples are epidemiologically valuable to obtain exact data in the region.

Synthesis, Antibacterial Evaluation, and Computational Studies of a Diverse Set of Linezolid Conjugates.

The development of new antibiotics to treat multidrug-resistant (MDR) bacteria or possess broad-spectrum activity is one of the challenging tasks. Unfortunately, there are not many new antibiotics in clinical trials. So, the molecular hybridization approach could be an effective strategy to develop potential drug candidates using the known scaffolds. We synthesized a total of 31 diverse linezolid conjugates 3, 5, 7, 9, 11, 13, and 15 using our established benzotriazole chemistry with good yield and purity. Some of the synthesized conjugates exhibited promising antibacterial properties against different strains of bacteria. Among all the synthesized compounds, 5d is the most promising antibacterial agent with MIC 4.5 µM against S. aureus and 2.25 µM against B. subtilis. Using our experimental data pool, we developed a robust QSAR (R2 = 0.926, 0.935; R2cvOO = 0.898, 0.915; R2cvMO = 0.903, 0.916 for the S. aureus and B. subtilis models, respectively) and 3D-pharmacophore models. We have also determined the drug-like properties of the synthesized conjugates using computational tools. Our findings provide valuable insight into the possible linezolid-based antibiotic drug candidates.

New quinoline-triazole conjugates: Synthesis, and antiviral properties against SARS-CoV-2.

At present therapeutic options for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are very limited. We designed and synthesized three sets of small molecules using quinoline scaffolds. A series of quinoline conjugates (10a-l, 11a-c, and 12a-e) by incorporating 1,2,3-triazole were synthesized via a modified microwave-assisted click chemistry technique. Among the synthesized conjugates, 4-((1-(2-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-6-fluoro-2-(trifluoromethyl)quinoline (10g) and 6-fluoro-4-(2-(1-(4-methoxyphenyl)-1H-1,2,3-triazol-4-yl)ethoxy)-2-(trifluoromethyl)quinoline (12c) show high potency against SARS-CoV-2. The selectivity index (SI) of compounds 10g and 12c also indicates the significant efficacy compared to the reference drugs.

Co-Existence of Carbapenemase-Encoding Genes in Acinetobacter baumannii from Cancer Patients.

INTRODUCTION: Acinetobacter baumannii is an opportunistic pathogen, which can acquire new resistance genes. Infections by carbapenem-resistant A. baumannii (CRAB) in cancer patients cause high mortality. METHODS: CRAB isolates from cancer patients were screened for carbapenemase-encoding genes that belong to Ambler classes (A), (B), and (D), followed by genotypic characterization by enterobacterial-repetitive-Intergenic-consensus-polymerase chain reaction (ERIC-PCR) and multilocus-sequence-typing (MLST). RESULTS: A total of 94.1% of CRAB isolates co-harbored more than one carbapenemase-encoding gene. The genes blaNDM, blaOXA-23-like, and blaKPC showed the highest prevalence, with rates of 23 (67.7%), 19 (55.9%), and 17 (50%), respectively. ERIC-PCR revealed 19 patterns (grouped into 9 clusters). MLST analysis identified different sequence types (STs) (ST-268, ST-195, ST-1114, and ST-1632) that belong to the highly resistant easily spreadable International clone II (IC II). Genotype diversity indicated the dissemination of carbapenem-hydrolyzing, ß-lactamase-encoding genes among genetically unrelated isolates. We observed a high prevalence of metallo-ß-lactamase (MBL)-encoding genes (including the highly-resistant blaNDM gene that is capable of horizontal gene transfer) and of isolates harboring multiple carbapenemase-encoding genes from different classes. CONCLUSION: The findings are alarming and call for measures to prevent and control the spread of MBL-encoding genes among bacteria causing infections in cancer patients and other immunocompromised patient populations.