Multi-antibiotic Resistance Research Articles

Effects of heavy metals pollution on the co-selection of metal and antibiotic resistance in urban rivers in UK and India

Heavy metal pollution and the potential for co-selection of resistance to antibiotics in the environment is growing concern. However, clear associations between heavy metals and antibiotic resistance in river systems have not been developed. Here we investigated relationships between total and bioavailable heavy metals concentrations; metal resistance gene (MRG) and antibiotic resistance gene (ARG) abundances; mobile genetic elements; and the composition of local bacterial communities in low and high metal polluted rivers in UK and India. The results indicated that MRGs conferring resistance to cobalt (Co) and nickel (Ni) (rcnA), and Co, zinc (Zn), and cadmium (Cd) (czcA), and ARGs conferring resistance to carbapenem and erythromycin were the dominating resistant genes across the samples. The relative MRGs, ARGs, and integrons abundances tended to increase at high metal polluted environments, suggesting high metals concentrations have a strong potential to promote metal and antibiotic resistance by horizontal gene transmission and affecting bacterial communities, leading to the development of multi-metal and multi-antibiotic resistance. Network analysis demonstrated the positive and significant relationships between MRGs and ARGs as well as the potential for integrons playing a role in the co-transmission of MRGs and ARGs (r > 0.80, p < 0.05). Additionally, the major host bacteria of various MRGs and ARGs that could be accountable for greater MRGs and ARGs levels at high metal polluted environments were also identified by network analysis. Spearman's rank-order correlations and RDA analysis further confirm relationships between total and bioavailable heavy metals concentrations and the relative MRG, ARG, and integron abundances, as well as the composition of related bacterial communities (r > 0.80 (or < −0.80), p < 0.05). These findings are critical for assessing the possible human health concerns associated with metal-driven antibiotic resistance and highlight the need of considering metal pollution for developing appropriate measures to control ARG transmission.

Screening for the Probiotic Activities of Lactic Acid Bacteria Isolated from the Gastrointestinal Tract of Traditional Poultry in Côte d'Ivoire

In the view to overcome the problem of antibiotic multi-resistance of pathogens encountered in poultry farming, the most appropriate strategy was suggested to be the use of probiotic lactic acid bacteria (LAB) strains. Thus, this study aimed to evaluate the probiotic properties of LAB isolated from gastrointestinal tract of Ivorian traditional chickens for potential application as probiotic in broiler production. So, after a preliminary screening for pH 2.0 tolerance, the probiotic characters like tolerance to bile salt, hydrophobicity, auto and co-aggregation properties, antimicrobial activity and antibiotic susceptibility were evaluated. The results showed that amongst the 90 LAB investigated, a total of 15 isolates were able to grow after 90 min exposed to pH 2.0. The resistance of these 15 isolates to 0.3% bile salt was more than 50%. A test of their adhesion ability to host epithelial cells using cell surface hydrophobicity produced a range of 50.25% to 92.57%. The isolates had weak auto-aggregation ability and high coaggregation with the pathogens Salmonella enteritidis and Escherichia coli. They had wide spectrum inhibitory activity against challenging zoonotic and foodborne pathogens. Furthermore, all the five selected strains showed resistance to Colistin while 60-80% resistance was demonstrated against Oxacillin, Gentamicin and Kanamycin. Based on above characteristics, the LAB strains Pediococcus acidilactici JK148 and Lactobacillus pentosus JK151 which showed excellent probiotic potentials were selected as chicken probiotic candidates.

Antibiotic Prophylaxis and Empirical Antibiotic Therapy in Primary Arthroplasty and Periprosthetic Joint Infections: Current Practice and Need for Therapy Optimization.

The aim of the present work was to survey the situation of healthcare regarding the use of prophylactic and empirical antibiotics in primary arthroplasty and treatment of periprosthetic joint infections (PJI). For this purpose, a survey was conducted at German university and occupational accident hospitals. Survey data was compared to previously published data on the antimicrobial regimes of PJI (n=81) patients (n=81) treated in our department between 2017 and 2020. A homogeneous picture emerged for the prophylactic administration of antibiotics in the context of primary arthroplasty. In 93.2% (elective) and 88.6% (fracture treatment) of the hospitals, first or second generation cephalosporins were administered perioperatively for infection prophylaxis in primary hip arthroplasty. The empirical antibiotic treatment of PJIs showed a clearly inhomogeneous therapeutic picture. Monotherapy with an aminopenicillin plus a beta-lactamase inhibitor is used most frequently (38.7%); first and second generation cephalosporins are used second most frequently as monotherapy (18.2%). In light of the global problem of antibiotic multi-resistance, clinical use of antibiotics has to be reasonable and effective. The present results highlight the further need to improve awareness and following existing guidelines in the administration of empirical antibiotic therapy in PJI.

Enterococcus faecium Isolates Present in Human Breast Milk Might Be Carriers of Multi-Antibiotic Resistance Genes

Using Enterococcus faecium strains as probiotics raises several controversies related to their antibiotic resistance (AR). In the current study, we examined isolates of E. faecium obtained from human breast milk. Catalase-negative and γ-haemolytic isolates were identified by analyzing the sequences of 16S rRNA gene and their phenotypic resistance to antibiotics was investigated. We examined the expression of genes that were found on plasmids. The majority of isolates tested were resistant to erythromycin (96%), followed by trimethoprim (67%), tetracycline (57%), and gentamicin (55%). Ninety-seven percent of E. faecium isolates were resistant to at least two antibiotics. We detected the presence of the following genes on plasmids: ErmB (erythromycin), dfrA17 (trimethoprim), tetO, tetK (tetracycline), Aph(3′)-IIIa (neomycin), and marA (rifampicin). TetO was not expressed in all cases, dfrA14 was not expressed in CDCP1449, while tetK was only expressed in CDCP1128 and CDCP1331 isolates. In the majority of isolates, AR genes were located on chromosomes since they were not detected on plasmids. Our study shows that due to the spread of AR, human milk could be one of the first sources of the bacteria resistant to antimicrobials to infants.

Epidemiological study on Listeria monocytogenes in Egyptian dairy cattle farms’ insights into genetic diversity of multi-antibiotic-resistant strains by ERIC-PCR

Listeria monocytogenes (L. monocytogenes) is frequently detected in ruminants, especially dairy cattle, and associated with the sporadic and epidemic outbreak of listeriosis in farms. In this epidemiological study, the prevalence, virulence, antibiotic resistance profiles, and genetic diversity of L. monocytogenes in three Egyptian dairy cattle farms were investigated. The risk factors associated with the fecal shedding of L. monocytogenes were analyzed. The L. monocytogenes strains from the three farms were categorized into distinct genotypes based on sampling site and sample type through enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). A total of 1896 samples were collected from animals, environments, and milking equipment in the three farms. Results revealed that 137 (7.23%) of these samples were L. monocytogenes positive. The prevalence of L. monocytogenes in the animal samples was high (32.1%), and the main environmental source of prevalent genotypes in the three farms was silage. For all sample types, L. monocytogenes was more prevalent in farm I than in farms II and III. Risk factor analysis showed seasonal variation in production hygiene. For all sample types, L. monocytogenes was significantly more prevalent in winter than in spring and summer. The level of L. monocytogenes fecal shedding was high likely because of increasing age, number of parities, and milk yield in dairy cattle. Two virulence genes, namely, hlyA & prfA, were also detected in 93 strains, whereas only one of these genes was found in 44 residual strains. Conversely, iap was completely absent in all strains. The strains exhibited phenotypic resistance to most of the tested antibiotics, but none of them was resistant to netilmicin or vancomycin. According to sample type, the strains from the animal samples were extremely resistant to amoxicillin (95.2%, 80/84) and cloxacillin (92.9%, 78/84). By comparison, the strains from the environmental samples were highly resistant to cefotaxime (86.95%, 20/23). Furthermore, 25 multi-antibiotic resistance (MAR) patterns were observed in L. monocytogenes strains. All strains had a MAR index of 0.22–0.78 and harbored antibiotic resistance genes, including extended-spectrum β-lactamase (blaCTX-M [92.7%] and blaDHA-1 [66.4%]), quinolones (qnrS [91.2%], qnrA [58.4%], parC [58.4%], and qnrB [51%]), macrolides (erm[B] [76.6%], erm(C) [1.5%], and msr(A) [27%]), trimethoprim (dfrD [65.7%]), and tetracyclines (tet(M) [41.6%], tet(S) [8%], and int-Tn [26.3%]). ERIC-PCR confirmed that the strains were genetically diverse and heterogeneous. A total of 137 isolated L. monocytogenes strains were classified into 22 distinct ERIC-PCR groups (A–V). Among them, ERIC E (10.2%) was the most prevalent group. These results indicated that environment and milking equipment served as reservoirs and potential transmission ways of virulent and multidrug-resistant L. monocytogenes to dairy animals, consequently posing threats to public health. Silage is the main environmental source of prevalent genotypes on all three farms. Therefore, hygienic measures at the farm level should be developed and implemented to reduce L. monocytogenes transmission inside dairy cattle farms.

Antibiotic Susceptibility and Plasmid Profile of Multidrug resistant Uropathogenic Serratia marcescens

Objectives: Genetic elements such as plasmids play a role in spreading multi-antibiotic resistance, a global threat. Therefore, the purpose of this study was to investigate the antibiotic susceptibility and plasmid profiles of multidrug-resistant (MDR) uropathogenic Serratia marcescens. Methods: Fifty Serratia marcescens isolates were obtained from urine samples of patients presenting with urinary tract infection (UTI) in Southeastern Nigeria. Bacteria samples were identified via their characteristic red pigmentation and other biochemical tests. The disc diffusion method was used for antibiotic susceptibility testing. Plasmids were extracted using the alkaline lysis method, and electrophoresis was done on a 1% agarose gel. Extracted DNA plasmids were visualized using the ultraviolet light illuminator and a photo documentation system. Plasmid curing was carried out using acridine orange. Results: Antibiotic susceptibility testing of isolates revealed 41 (82%) were resistant to one or more antibiotics tested, and 8 (16%) isolates exhibited resistance to three or more antibiotics (MDR). Of the eight MDR isolates, five (63%) had plasmids with molecular weights ranging from 33 kb to 58 kb. One isolate (S9) was cured and became sensitive to ceftriaxone, but not cefuroxime or ceftazidime. Notably, one isolate (S23), initially sensitive to ciprofloxacin, became resistant post-plasmid curing. Conclusion: The findings show that most resistant bacteria containing plasmids were immune to curing as they remained resistant to antibiotics after curing. This result confirms a concern about the growing presence of MDR plasmids of S. marcescens in healthcare facilities in Southeastern Nigeria. J Microbiol Infect Dis 2022; 12(1):12-18.

Rosmarinus officinalis Might be Exploited as a Natural Antifouling Agent: A Potentially Promising Strategy for Curbing Membrane Biofouling

Membrane biofouling is the coverage of membrane surfaces due to undesirable development of biofilms causing a decrease and subsequent loss of productivity in water treatment settings. Continuous use of synthetic chemicals against biofouling is inept as it leads to the emergence of multi-antibiotic resistance. Application of natural products such as plants can be apt in curbing biofouling while checking the resistance challenge. This study aimed to evaluate the potential of Rosmarinus officinalis in the control of membrane biofouling. Bacteria from biofouling environments were subjected to a biofilm confirmation test and identified at cultural, morphological, biochemical and molecular levels. Leaves of R.officinalis were extracted in solvents of varying polarity and activities. These extracts were evaluated against bacterial biofilm formation via minimum biofilm inhibitory concentration (MBIC), minimum biofilm eradication concentration (MBEC) and mesocosm bioassays. Biofilm formation was confirmed in 68% of the isolates identified as Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus. The methanol and ethyl acetate extracts of R.officinalis indicated the least MICs (0.313mg/L and 1.25mg/L) against Pseudomonas aeruginosa and Staphylococcus aureus, respectively. Both extracts recorded the highest MBIC (50.00%) against Pseudomonas aeruginosa. The peak MBEC (57.88%) was obtained from the methanol extract against Staphylococcus aureus and this same extract inhibited 56.23% density of bacterial biofilms on glass slides.The methanol and ethyl acetate crude extracts of R. officinalis appreciably reduced bacterial biofilms; hence, this plant can be exploited as a natural antifouling agent, with reduced toxicity and low risk of resistance.

Pathogenicity of newly emerged bacterial pathogens, Pseudomonas stutzeri and P. oleovorans, in the Red Sea seabream Diplodus noct

Pseudomonas is one of the most varied genera noted for its metabolism and genetic versatilities, which enable it to survive in various environmental conditions, including marine habitats. Pseudomonas species associated with fish diseases have rapidly increased, and new species are constantly being isolated. In this study, two newly emerged marine Pseudomonas pathogens, AMP-HB1 and AMP-FB1, were isolated from infected blackspot snapper, Lutjanus ehrenbergii, and blacktail butterflyfish, Chaetodon austriacus, from the National Institute of Oceanography and fisheries aquarium in Hurghada. External signs of naturally infected fish were ulcers, erosion, ophthalmitis, and cutaneous hemorrhage. The results of 16S rDNA sequencing and phylogenetic analysis confirmed that the AMP-HB1 and AMP-FB1 isolates were Pseudomonas stutzeri and P. oleovorans/pseudoalcaligenes, respectively. A challenge experiment was conducted in which the Red Sea seabream Diplodus noct were injected with a series of three different doses of 1 × 107, 1.5 × 108, and 3 × 108 CFU from each isolate. After 7 days, the survival rates were found to be 25%, 16.6%, and 0% for P. stutzeri and 66.6%, 16.6%, and 0% for P. oleovorans, respectively. In addition, P. stutzeri exhibited multiantibiotic resistance to streptomycin, chloramphenicol, and ciprofloxacin. As well, P. oleovorans exhibited 100% resistance to the antibiotics used in this study.

Knockout of Tobacco Homologs of Arabidopsis Multi-Antibiotic Resistance 1 Gene Confers a Limited Resistance to Aminoglycoside Antibiotics.

To explore a possible recessive selective marker for future DNA-free genome editing by direct delivery of a CRISPR/Cas9-single guide RNA (sgRNA) ribonucleoprotein complex, we knocked out homologs of the Arabidopsis Multi-Antibiotic Resistance 1 (MAR1)/RTS3 gene, mutations of which confer aminoglycoside resistance, in tobacco plants by an efficient Agrobacterium-mediated gene transfer. A Cas9 gene was introduced into Nicotiana tabacum and Nicotiana sylvestris together with an sgRNA gene for one of three different target sequences designed to perfectly match sequences in both S- and T-genome copies of N. tabacum MAR1 homologs (NtMAR1hs). All three sgRNAs directed the introduction of InDels into NtMAR1hs, as demonstrated by CAPS and amplicon sequencing analyses, albeit with varying efficiency. Leaves of regenerated transformant shoots were evaluated for aminoglycoside resistance on shoot-induction media containing different aminoglycoside antibiotics. All transformants tested were as sensitive to those antibiotics as non-transformed control plants, regardless of the mutation rates in NtMAR1hs. The NtMAR1hs–knockout seedlings of the T1 generation showed limited aminoglycoside resistance but failed to form shoots when cultured on shoot-induction media containing kanamycin. The results suggest that, like Arabidopsis MAR1, NtMAR1hs have a role in plants’ sensitivity to aminoglycoside antibiotics, and that tobacco has some additional functional homologs.

Hormesis Effect of Pyroligneous Acids on Conjugative Transfer of Plasmid-Mediated Multi-Antibiotic Resistance Genes within Bacterial Genus

Hormesis Effect of Pyroligneous Acids on Conjugative Transfer of Plasmid-Mediated Multi-Antibiotic Resistance Genes within Bacterial Genus

Identification of Small Molecule Inhibitors of the Pathogen Box against Vibrio cholerae.

ABSTRACTAntimicrobial resistance (AMR) has become a serious public and economic threat. The rate of bacteria acquiring AMR surpasses the rate of new antibiotics discovery, projecting more deadly AMR infections in the future. The Pathogen Box is an open-source library of drug-like compounds that can be screened for antibiotic activity. We have screened molecules of the Pathogen Box against Vibrio cholerae, the cholera-causing pathogen, and successfully identified two compounds, MMV687807 and MMV675968, that inhibit growth. RNA-seq analyses of V. cholerae after incubation with each compound revealed that both compounds affect cellular functions on multiple levels including carbon metabolism, iron homeostasis, and biofilm formation. In addition, whole-genome sequencing analysis of spontaneous resistance mutants identified an efflux system that confers resistance to MMV687807. We also identified that the dihydrofolate reductase is the likely target of MMV675968 suggesting it acts as an analog of trimethoprim but with a MIC 14-fold lower than trimethoprim in molar concentration. In summary, these two compounds that effectively inhibit V. cholerae and other bacteria may lead to the development of new antibiotics for better treatment of the cholera disease.IMPORTANCE Cholera is a serious infectious disease in tropical regions causing millions of infections annually. Vibrio cholerae, the causative agent of cholera, has gained multi-antibiotic resistance over the years, posing greater threat to public health and current treatment strategies. Here we report two compounds that effectively target the growth of V. cholerae and have the potential to control cholera infection.

Identification of multi-antibiotic resistant bacteria isolated from Vietnamese climbing perch (Anabas testudineus) on fish farms in Ho Chi Minh City, Vietnam

Climbing perch (Anabas testudineus) is considered a cultured species with high economic value and is widely distributed in several Asian countries, including Vietnam. In climbing perch aquaculture, antibiotic and antibacterial agents have been overused, leading to the emergence of antibiotic-resistant bacteria or genes in the aquatic environment as well as in the seafood products. These antibiotic-resistant bacteria and/or genes can then be spread to human through the food chain, generating detrimental consequences for public health and environment. In this study, 14 bacterial strains were isolated from Vietnamese climbing perch collected from various fish farms in Ho Chi Minh City which possess abnormal symptoms on the outside and in their organs. These bacterial strains were then subjected to several biochemical tests to characterize their colony morphologies. Besides, gene sequencing was performed and as compared to the 16S rRNA, 4 bacterial strains were identified with a high percentage in similarity, including Pseudomonas aeruginosa (99.7%), Aeromonas caviae (99.93%), Kosakonia sacchari (100%), and Edwardsiella ictaluri (99.44%). Additionally, these bacteria showed high levels of antibiotic resistance against beta-lactam, tetracycline, and others. Taken together, these results showed that the four identified bacterial strains isolated from Vietnamese climbing perch circulated in fish farms in Ho Chi Minh City. Their current status of multi-antibiotic resistance indicates further alternative sources of antimicrobial agents, for example, natural compounds, to overcome antibiotic resistance. It is then crucial to identify fish diseases, the associated pathogens, and the new alternatives for antibiotics to protect aquatic ecosystems and water resources.

Characteristics of Post-Neurosurgical Nosocomial Bacterial Meningitis in Adults: A retrospective Cross-Sectional Study

Aim: To analyze the characteristics of Post-neurosurgical nosocomial bacterial meningitis in adults Study design: A retrospective cross-sectional study Place and duration: Riyadh Care Hospital/ National Care Hospital, from July 2005 to June 2010 then 2013 to 2018. Methodology: Over ten years, sixty-two patients above the age of 16 years who suffered from Post-neurosurgical nosocomial bacterial meningitis were evaluated by collecting clinical data. The cases were divided into two categories, the first one from July 2007 to June 2012 and second one from August 2013 to July 2018. Results: Among the 62 patients, there were 43 males and 19 females with post-neurosurgical nosocomial bacterial meningitis. It was recorded in the first group that the percentage of post-neurosurgical nosocomial meningitis in all culture-proven adult bacterial meningitis was 12 percent and for the second group it was seen to be 27 percent. The most constant clinical characteristics were fever and gradual consciousness disruption, which may be related to various postoperative neurosurgery issues. The most prevalent pathogens were recorded to be pseudomonas aeruginosa, staphylococcus aureus, coagulase-negative staphylococcus, Acinetobacter baumannii, and lastly, Escherichia coli. During the second era, there was a rise in polymicrobial illnesses and multi antibiotic resistance. Mortality was 22% in the first group of the study and 36% in the second group of the study. Conclusion: The selection of appropriate empirical antibiotics is complex and is necessary to be guided by knowledge of the comparative ratio of multiple diseases as well as the rising prevalence of resistant strains. To increase the likelihood of survival, early diagnosis is suggested with optimal antibiotic selection based on in vitro susceptibility testing, epidemiologic patterns, and lastly, metabolic derangement treatment to be advised and required. Keywords: Bacterial Meningitis, adults, post-neurosurgery

Antibiotics Resistance Pattern of Staphylococcus aureus Isolated From In-patients of an Orthopaedic Hospital in North-Western Nigeria

Background and aims: Staphylococcus aureus, an important pathogen in bone diseases, is a highly multi-drug resistant (MDR) bacterium. This study aimed to investigate the antibiotic resistance among S. aureus isolated from patients on admission in an orthopaedic hospital. Methods: In this cross-sectional research, 140 samples comprising urine samples, wound swabs, and nasal swabs were collected from 49 patients on admission. Samples were cultured and screened for S. aureus following standard procedures. Using the agar-disk diffusion method, the isolates were subjected to antibiotics susceptibility tests. Results: S. aureus were isolated from 26 (18.6%) samples, and wound swabs were found to have the highest number of the S. aureus isolates with 12 (46.2%). Among the 26 S. aureus isolated, 25 (96.2%) isolates were resistant to at least four or more of the tested antibiotics. There were 23 (88.5%) MDR isolates, while there were only 2 (7.6%) extensively drug resistant ones. The number of methicillin-resistant S. aureus were 17 (65.4% of the isolates), while the number of methicillin-susceptible S. aureus were 9 (34.6% of the isolates). A total of 22 (84.6%) isolates had multi-antibiotic resistance (MAR) index greater than 0.2. Inducible clindamycin resistance of 2 (7.6%) was observed. Conclusion: This study showed that the S. aureus isolated from the patients were resistant to multiple antibiotics. Regular surveillance of antibiotic resistance is of utmost importance, since it facilitates the design or development of the treatment regimens that could check the spread of antimicrobial resistance.

Association of blood isolate's multi antibiotic resistance-index on laboratory-confirmed bloodstream infection: A cross-sectional study

BackgroundA not optimal way of the insertion of the intravenous catheter can be one of the factors that cause bloodstream infection (BSI) that should be confirmed with blood culture, and if positive it is called Laboratory-Confirmed Bloodstream Infection (LCBI). One of the surveillance methods of nosocomial infection that is commonly used is the Multi Antibiotic Resistance (MAR)-Index. The aimed of study was association of MAR-index from blood isolates on LCBI category. MethodThis study used a cross-sectional study with a consecutive sampling method. Data collection for this study includes identification of micromaterial profile, antimicrobial test, MAR-Index, and LCBI category. The analysis used is the Mann Whitney test with p < 0.05. ResultThere were 43 isolates of LCBI 1, 26 isolates of LCBI 2, and none of the LCBI 3. Microorganisms in the LCBI category 1 were Staphylococcus aureus (53.4%), Acinetobacter baumannii (20.9%), Escherichia coli (9.3%), Klebsiella pneumonia (7.0%), Pseudomonas aeruginosa (4.7%), and Enterococcus faecalis (4.7%) with the MAR-Index ranged from 0.22 to 0.91. Microorganisms in the LCBI category 2 were Staphylococcus haemolyticus (69.3%), Staphylococcus epidermidis (19.3%), Staphylococcus hominis (3.8%), Streptococcus viridans (3.8%), and Corynebacterium jeikeium (3.8%) with the MAR-Index ranging between 0.11 and 0.79. There is no significant difference of MAR-index between LCBI 1 and 2 (p = 0.424) and no association of MAR-index on LCBI (p = 0.571). ConclusionMost LCBI type 1 is Staphylococcus aureus and LCBI type 2 is Staphylococcus haemolyticus which there is no significant association of MAR-index on LCBIs.

Antibiofilm Activity of Gallium(III) Complexed Anionic Polymers in Combination with Antibiotics.

Pseudomonas aeruginosa (P. aeruginosa) is a life-threatening pathogen associated with multiantibiotic resistance, which is largely caused by its strong ability to form biofilms. Recent research has revealed that gallium (III) shows an activity against the biofilm of P. aeruginosa by interfering with Fe metabolism. The antibacterial activity of the combination of Ga3+ ion and antibiotic rifampicin (RMP) against P. aeruginosa PAO1 is investigated. An anionic polymer poly{{2-[(2-methylprop-2-enoyl)oxy]ethyl}phosphonic acid} (PDMPOH) is exploited to form complexes (GaPD) with Ga3+ . The GaPD complexes act as a carrier of Ga3+ and release Ga3+ via enzymatic degradation by bacterial lipases. GaPD is found to damage the outer membrane, leading to enhanced cellular uptake of RMP and Ga3+ due to increased outer membrane permeability, which inhibits the RNA polymerase and interferes with Fe metabolism. The antibiofilm activity and biocompatibility of the GaPD system offer a promising treatment option for P. aeruginosa biofilm-related infections.

Effects of the prebiotic lactoferrin on multidrug-resistant Escherichia coli infections in broiler chickens.

Background and Aim:Increased multidrug resistance in Escherichia coli has created challenges for the poultry industry. Consequently, new antimicrobial agents should preferentially be utilized for the prevention and treatment of E. coli outbreaks. This study aimed to evaluate the effects of lactoferrin (LF) as a prebiotic on broiler chicks challenged with multidrug-resistant E. coli in comparison with antibiotics.Materials and Methods:A total of 70 diseased flocks from Egypt were collected for E. coli isolation and identification, serotyping, and antimicrobial susceptibility pattern determination. E. coli was isolated and characterized phenotypically and one isolate that showed multidrug-resistance was selected. A challenge trial was performed to evaluate the effectiveness of LF as a prebiotic on the isolated multidrug-resistant E. coli. Liver samples were collected from the experimental chicks and subjected to E. coli enumeration to illustrate the effectiveness of LF on the liver cells and bacteria using an electron microscope. Serum samples were also collected to estimate lysozyme and nitric oxide (NO) concentrations.Results:After isolation of E. coli with a percentage of 54.3% from the diseased broilers, the strain was serotyped (identified serotypes: O2, O18, O55, O78, O86a, O111, O125, O126, O127, O157, O159, and O166). Multi-antibiotic resistance was found to be harbored in a high percentage among 11 antibiotic discs. The LF in the prophylactic and treated groups was found to have a significant effect in comparison with the group treated with the drug of choice (ciprofloxacin). Furthermore, a significant difference in the NO (one of non-specific immune response) and a non-significant difference in lysozyme concentrations were reported in the group fed on rations with LF in comparison with the non-fed group.Conclusion:LF was thus identified as an effective prebiotic that can improve chick performance, help them to overcome multidrug-resistant E. coli and stimulate immunity.

Chlorination contributes to multi-antibiotic resistance in a pilot-scale water distribution system

Abstract The generation and dissemination of antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) in the environment has become a critical risk to human health. This study is based on a pilot-scale simulated water distribution system to understand the effects of chlorine disinfection treatment (without free chlorine) on ARB and ARGs in biofilms. The hydraulic parameters and pipe materials of the system were simulated based on a drinking water system. The results of the colony counts showed that bacterial multi-antibiotic resistance could be enhanced 13-fold in the biofilms of the pipeline. The use of high-throughput qPCR (HT-qPCR) indicated that the total relative abundance of ARGs in biofilm samples increased significantly (p &amp;lt; 0.05), while the diversity of bacteria was shown to be reduced via taxonomic analysis of the V3–V4 region of 16S rRNA. The prominent types of ARGs were conferred resistance by aminoglycoside and β-lactam after the chlorine disinfection treatment, and antibiotic deactivation was the main mechanism. Phyla Proteobacteria had the highest abundance in both treatment and control groups but decreased from 70.81% (initial biofilm sample) to 26.09% (the sixth-month biofilm sample) in the treatment groups. The results show that the chlorine disinfection plays a role in the risk of development of bacterial antibiotic resistance in pipe networks owing to bacteria in biofilms. This study was the first to investigate the contribution of chlorination without free chlorine to the bacterial community shift and resistome alteration in biofilms at a pilot-test level.

From the Andes to the desert: 16S rRNA metabarcoding characterization of aquatic bacterial communities in the Rimac river, the main source of water for Lima, Peru.

The Rimac river is the main source of water for Lima, Peru’s capital megacity. The river is constantly affected by different types of contamination including mine tailings in the Andes and urban sewage in the metropolitan area. In this work, we aim to produce the first characterization of aquatic bacterial communities in the Rimac river using a 16S rRNA metabarcoding approach which would be useful to identify bacterial diversity and potential understudied pathogens. We report a lower diversity in bacterial communities from the Lower Rimac (Metropolitan zone) in comparison to other sub-basins. Samples were generally grouped according to their geographical location. Bacterial classes Alphaproteobacteria, Bacteroidia, Campylobacteria, Fusobacteriia, and Gammaproteobacteria were the most frequent along the river. Arcobacter cryaerophilus (Campylobacteria) was the most frequent species in the Lower Rimac while Flavobacterium succinicans (Bacteroidia) and Hypnocyclicus (Fusobacteriia) were the most predominant in the Upper Rimac. Predicted metabolic functions in the microbiota include bacterial motility and quorum sensing. Additional metabolomic analyses showed the presence of some insecticides and herbicides in the Parac-Upper Rimac and Santa Eulalia-Parac sub-basins. The dominance in the Metropolitan area of Arcobacter cryaerophilus, an emergent pathogen associated with fecal contamination and antibiotic multiresistance, that is not usually reported in traditional microbiological quality assessments, highlights the necessity to apply next-generation sequencing tools to improve pathogen surveillance. We believe that our study will encourage the integration of omics sciences in Peru and its application on current environmental and public health issues.

The Role of Biofilm Formation in Antibiotic Resistance of Bacteria Isolated from Saliva of Patients with Dental Caries

Objectives: This study aim to determine the bacterial diversity, biofilm forming ability and the antimicrobial resistance of bacteria isolated from saliva of patients with dental caries conditions with the using of 16S rRNA gene sequencing technique for identification of the most virulent isolates.&#x0D; Methods: Isolation and identification of microorganisms were done employing standard bacteriologic techniques, followed by biofilm detection using tissue culture plate method. The strong biofilm forming isolates were selected for antibiotic susceptibility test against selected antibiotics using disk diffusion technique. In order to identify the selected isolates. The genomic DNA obtained following the extraction process were used for the amplification of the bacterial 16S rRNA gene.&#x0D; Results: A total of 137 bacterial isolates were obtained and identified as belonging to 21 genera. Tissue culture plate (TCP) method were employed for screening the isolates according to its biofilm forming ability, its showed that 55 (40.1%) of the total isolates were strong, 57 (41.6%) were moderate and 25 (18.3%) were weak biofilm producers. The antimicrobial susceptibility test showed the multi antibiotics resistance of the strong biofilm former isolates to the conventional antibiotics. Enterococcus faecalis isolates showed the highest biofilm formation and antibiotic resistance. The 16S rRNA gene for two of these isolates have been amplified using PCR and the product sequenced, analyzed and registered in the National Center for Biotechnology Information (NCBI) as UKMS1 and UKMS2 and the accession numbers KX960104.1 and KX960105.1 respectively.&#x0D; Conclusion: The study has revealed that antimicrobial resistance of bacteria isolates from saliva of patients with dental caries conditions is associated with biofilm formation. Other uncommon pathogenic bacteria were also isolated in this study as a result of the use of non-selective enrichment medium for culturing. Enterococcus faecalis isolates indicated the highest biofilm formation and antibiotic resistance.