The Atypical Antipsychotic Quetiapine Induces Multiple Antibiotic Resistance in Escherichia coli

Atypical antipsychotic (AAP) medication is a critical tool for treating symptoms of psychiatric disorders. While AAPs primarily target dopamine (D2) and serotonin (5HT2A and 5HT1A) receptors, they also exhibit intrinsic antimicrobial activity as an off-target effect. Because AAPs are often prescribed to patients for many years, a potential risk associated with long-term AAP use is the unintended emergence of bacteria with antimicrobial resistance (AMR). Here, we show that exposure to the AAP quetiapine at estimated gut concentrations promotes AMR in Escherichia coli after six weeks. Quetiapine-exposed isolates exhibited an increase in minimal inhibitory concentrations (MICs) for ampicillin, tetracycline, ceftriaxone, and levofloxacin. By whole genome sequencing analysis, we identified mutations in genes that confer AMR, including the repressor for the multiple antibiotic resistance mar operon (marR), and real-time RT-qPCR analysis showed increased levels of marA, acrA, and tolC mRNAs and a reduced level of ompF mRNA in the isolates carrying marR mutations. To determine the contribution of each marR mutation to AMR, we constructed isogenic strains carrying individual mutant marR alleles in the parent background and re-evaluated their resistant phenotypes using MIC and RT-qPCR assays. While marR mutations induced a robust activity of the mar operon, they resulted in only a modest increase in MICs. Interestingly, although these marR mutations did not fully recapitulate the AMR phenotype of the quetiapine-exposed isolates, we show that marR mutations promote growth fitness in the presence of quetiapine. Our findings revealed an important link between the use of AAPs and AMR development in E. coli.

High prevalence of multiple antibiotic resistance in clinical E. coli isolates from Bangladesh and prediction of molecular resistance determinants using WGS of an XDR isolate

Multi-drug-resistance (MDR) is a severe public health concern worldwide, and its containment is more challenging in developing countries due to poor antimicrobial resistance (AMR) surveillance and irrational use of antibiotics. The current study investigated 100 clinical E. coli isolates and revealed that 98% of them were MDR. PCR analysis using 25 selected isolates showed the predominance of metallo-β-lactamase gene blaNDM (80%) and ESBL genes blaOXA (48%) and blaCTX-M-15 (32%). The AmpC gene was detected in 68% of the isolates, while 32% was tetC positive. Notably, 34% of the isolates were resistant to carbapenem. Whole genome sequence (WGS) analysis of an extensively drug-resistant (XDR) isolate (L16) revealed the presence of the notorious sequence type 131 responsible for multi-drug-resistant infections, multiple antibiotic resistance genes (ARGs), virulence genes, and mobile genetic elements that pose risks to environmental transmission. Our results indicate that MDR is alarmingly increasing in Bangladesh that critically limits the treatment option against infections and contributes to further aggravation to the prevailing situation of MDR worldwide. The findings of this study will be valuable in designing sustainable strategies to contain MDR in the region.

Isolation, Identification and Antibiotic Susceptibility of Escherichia coli Isolated from Raw Meat from Modake and Ile-Ife, Osun State, Nigeria

The study reported isolation, identification and antibiotic susceptibility of Escherichia coli isolated from raw meat from Modakeke and Ile-ife, Osun State, Nigeria, with the view to determining the antibiogram profiling of the bacterial isolates. In this study, five samples of fresh meat were collected from different abattoirs in Ile-Ife and Modakeke, Osun State. Isolates of Escherichia coli were isolated, identified morphologically based on their growth on nutrient agar and subjected to antibiotic susceptibility test on Mueller Hinton agar. The mean microbial load from the meat samples ranged from 8.85 x 102cfu/ml to 5.77 x 104cfu/ml. A total of 69 E. coli isolates were recovered from the meat sampled. All the isolates appeared cream, translucent, entire, convex, circular, smooth and glistering. The isolates were identified as Gram negative rods, non-motile, lactose fermenters, positive for indole test and negative for citrate utilization test. All the E. coli isolates were resistant to augmentin, ceftriazone, nitrofurantoin and gentamycin. 98.55% of E. coli isolated was resistant to amoxillin and the least resistant was recorded in ofloxacin (8.70%). However, 91.30% of the E. coli isolates was sensitive to ofloxacin, 81.16% to ciprofloxacin and 36.23% to pefloxacin while none was sensitive to augmentin, ceftriazone, nitrofurantoin and gentamycin. A total of 19 different multiple antibiotic resistance patterns were observed among the isolates. Thirty isolates (43.48%) showed multiple antibiotic resistance to 5 and 10 different antibiotic types each. The study concluded that occurrence of E. coli infection is high in the study area with high level of multiple antibiotic resistance.

Sulfane Sulfur Is a Strong Inducer of the Multiple Antibiotic Resistance Regulator MarR in Escherichia coli

Sulfane sulfur, including persulfide and polysulfide, is produced from the metabolism of sulfur-containing organic compounds or from sulfide oxidation. It is a normal cellular component, participating in signaling. In bacteria, it modifies gene regulators to activate the expression of genes involved in sulfur metabolism. However, to determine whether sulfane sulfur is a common signal in bacteria, additional evidence is required. The ubiquitous multiple antibiotic resistance regulator (MarR) family of regulators controls the expression of numerous genes, but the intrinsic inducers are often elusive. Recently, two MarR family members, Pseudomonas aeruginosa MexR and Staphylococcus aureus MgrA, have been reported to sense sulfane sulfur. Here, we report that Escherichia coli MarR, the prototypical member of the family, also senses sulfane sulfur to form one or two disulfide or trisulfide bonds between two dimers. Although the tetramer with two disulfide bonds does not bind to its target DNA, our results suggest that the tetramer with one disulfide bond does bind to its target DNA, with reduced affinity. An MarR-repressed mKate reporter is strongly induced by polysulfide in E. coli. Further investigation is needed to determine whether sulfane sulfur is a common signal of the family members, but three members sense cellular sulfane sulfur to turn on antibiotic resistance genes. The findings offer additional support for a general signaling role of sulfane sulfur in bacteria.

Multiple Antibiotic Resistance of Airborne Bacteria in Outdoor Markets in Ado-Ekiti Metropolis

The emergence of multiple antibiotic resistant strains in the environment, particularly in a densely populated market is a problem to the infection management. The prevalence of antibiotic- resistant airborne bacteria was examined in five different outdoor markets in Ado Ekiti, Ekiti State, Nigeria. The sample collection was taken between 3-5pm when activities at the market place were at the peak. The bacteria isolates were identified and their antibiotic susceptibility to fourteen different antibiotics was carried out. Six genera of bacteria were recovered, Staphylococcus (16.7%), Escherichia (18.6%), Pseudomonas (21.6%), Enterococcus (19.6%), Salmonella (10.8 %) and Klebsiella (12.7%). The airborne isolates showed the highest resistance to Pefloxacin (52.3%), followed by Augumentin (44.7%). The lowest resistance was to Erythromycin (5.8%). All of Salmonellae typhimurium, and Escherichia coli were multiple antibiotic resistant (MAR), while a great percentage of otherisolates were also MAR (Staphylococcus aureus (88.3%), Pseudomonas aeruginosa (90.9%), Klebsiella pneumoniae (92.3%), and Enterococcus spp (85%). These results show that the air in the outdoor markets studied was highly contaminated with a great diversity of MAR bacteria. The findings of this study will be helpful in the intervention of health officials and policy makers in decision making towards the effective control of infections caused by the airborne bacteria in the outdoor markets.

Antimicrobial Resistance of Listeria monocytogenes Strains Isolated from Humans, Animals, and Food Products in Russia in 1950–1980, 2000–2005, and 2018–2021

Susceptibility of 117 L. monocytogenes strains isolated during three time periods (1950–1980; 2000–2005, and 2018–2021) to 23 antibiotics was tested by the disk diffusion method. All strains were sensitive to aminoglycosides (gentamicin, kanamycin, neomycin, streptomycin), glycopeptides (vancomycin and teicoplanin), clarithromycin, levofloxacin, amoxicillin/clavulanic acid, and trimethoprim/sulfamethoxazole. Resistance to clindamycin was observed in 35.5% of strains. Resistance to carbapenems, imipenem and meropenem was found in 4% and 5% of strains, respectively. Resistance to erythromycin, penicillin G, trimethoprim, and ciprofloxacin was found in 4%, 3%, 3%, and 2.5% of strains, respectively. Resistance to tylosin, ampicillin, enrofloxacin, linezolid, chloramphenicol, and tetracycline was found in less than 2%. Three strains with multiple antibiotic resistance and 12 strains with resistance to two antibiotics were revealed. Comparison of strains isolated in different time periods showed that the percentage of resistant strains was the lowest among strains isolated before 1980, and no strains with multiple antibiotic resistance were found among them. Statistical analysis demonstrated that the temporal evolution of resistance in L. monocytogenes has an antibiotic-specific character. While resistance to some antibiotics such as ampicillin and penicillin G has gradually decreased in the population, resistance to other antibiotics acquired by particular strains in recent years has not been accompanied by changes in resistance of other strains.

Antibiotic susceptibility pattern of Escherichia coli isolated from food, cooking utensils and palms of food handlers in some restaurants in Zaria, Nigeria

Foodborne disease is a major public health problem causing considerable morbidity and mortality annually. In the present study, the antibiotic susceptibility patterns of Escherichia coli isolated from food, cooking utensils and palms of food handlers in some restaurants in Zaria, Nigeria were evaluated. A total of 250 samples (220 food samples, 7 hand samples of food handlers, 10 plate samples within restaurants and 13 spoon samples) were collected from five locations in Zaria, Nigeria and analysed for microbial contaminations using standard microbiological techniques. The antibiotic susceptibility pattern of the isolates was determined using Kirby-Bauer modified disc agar diffusion technique. Results revealed that out of 158 acclaimed Enterobacteriaceae isolates evaluated, 19 % (30) were confirmed to be E. coli, while 81 % were Klebsiella. spp, Citrobacter fruendii, Enterobacter spp, Shigella spp, Salmonella spp, Serratia spp, and Cronobacter sakazaki. The majority of the isolates were resistant to amoxiclav (26.08%), ampicillin (26.08%), tetracycline (26.08%) and metronidazole (13.04%). A 33.3% of the isolates were multidrug-resistant. The E. coli isolates were mostly multiple antibiotic resistance with 43.3% having multiple antibiotic resistance index (MARI) ≥ 0.2. In conclusion, E. coli evolved resistance to ampicillin, Amoxicillin Clavulanic acid, and Tetracycline and other tested antimicrobial drugs which would make the treatment of Escherichia coli infections difficult