Colistin Research Articles

Prevalence and Antibiogram of Clostridium perfringens in Small Ruminants of District Kalat, Balochistan

Background: Among life-threatening infections of small ruminants (sheep/goat), enterotoxaemia has vital importance. This disease is caused by certain serotype of Clostridium perfringens and commonly known as pulpy kidney or overeating infection. The current study was carried out to determine the prevalence of C. perfringens in small ruminants in different zones (Kalat, Mangochar, Johan, and Gazg) of district Kalat, Balochistan. Methods: Fecal samples (n=100) were collected aseptically, from rectum of enterotoxaemia suspected animals. The samples were cultured in Reinforced Clostridial Media (RCM). Biochemically identified isolates were further confirmed through polymerase chain reaction (PCR). Result: Overall prevalence of C. perfringens was noticed 48%, with higher occurrence rate (p less than 0.01) in sheep (60%) than goat (36%). Among fifty samples of each specie, 30 and 18 isolates recovered from sheep and goat respectively. The area wise analysis showed that, in goats, the highest prevalence was found in Kalat (50%) followed by the Mangochar (38.46%), Johan (30.77%) and Gazg (25%). The statistical analysis revealed the significant differences (p less than 0.05; 95% confidence interval (CI) 18.80-68.91) in C. perfringens prevalence in various areas of Kalat district. The results of the gender-wise prevalence of C. perfringens exhibited a numerically higher (p greater than 0.05; 95% CI 9.23-49.02) prevalence in female goats (40%) than male goats (32%). Whereas, the age-wise analysis indicated that, in less than 1 year age group (44.44%), the prevalence of C. perfringens was higher (p less than 0.05; 95% CI 8.00-57.89) than greater than 1 but less than 2 years (29.41%) and ³ 2-year (33.33%) age groups. Similarly, in sheep, the highest prevalence (p less than 0.05) was found in Kalat (76.92%) followed by Mangochar (66.67%), Johan (58.33%) and Gazg (38.46%). The age wise and gender-wise differences (p less than 0.05) were also observed in various age and gender groups of sheep similar to goat. Among 30 sheep isolates of C. perfringens, a highest number (28 isolates) showed resistance against amikacin, followed by amoxicillin/penicillin (25 isolates) and colistin sulphate (22 isolates); while among 18 isolates of goat 17 were found resistant against colistin sulphate and 16 were resistant against amoxicillin and amikacin. In conclusion enterotoxaemia is prevailing in small ruminants of district Kalat, Balochistan thus mass scale vaccination campaign should be carried out to prevent losses.

Analysis of antibiotic resistance of KPC-2-positive Klebsiella pneumoniae strains isolated from blood cultures in Van, Turkey.

Recently, Klebsiella pneumoniae strains causing bacteremia and showing significant antibiotic resistance have raised serious health concerns. Especially carbapenem-resistant K. pneumoniae has spread worldwide and caused an increase in mortality rates. In this study, we aimed to present information about KPC-2 carriage and molecular characteristics of K. pneumoniae strains showing multiple antibiotic resistance among patients in our hospital. Blood samples were collected from patients hospitalized in the intensive care units (ICU) of Van Regional Training and Research Hospital between 2020-2021. Culture, biochemical tests, antibiotic susceptibility tests, and molecular tests were performed to identify K. pneumoniae strains isolated from blood culture samples. Two hundred and sixteen K. pneumoniae were isolated from patients with positive blood cultures. Twenty-seven of these isolates showed multidrug resistance. Carbapenem, β-lactam, and quinolone resistance were particularly high. On the contrary, almost all of these isolates were susceptible to Amikacin (AK), Gentamicin (CN), Colistin (CT) and Tigecycline (TGC). Molecular analysis revealed that all of these isolates were KPC-2-positive and ST11 variants. It was observed that KPC-2- positive K. pneumoniae strains with multi-drug resistance may pose a serious risk in patients hospitalized in ICU in our hospital. It was concluded that surveillance and personnel training regarding the hospital and community-acquired infections due to these isolates that show pandemic spread would be important.

Dissemination of mcr-1 and β-lactamase genes among Pseudomonas aeruginosa: molecular characterization of MDR strains in broiler chicks and dead-in-shell chicks infections

ObjectivesPseudomonas aeruginosa (P. aeruginosa) is one of the most serious pathogens implicated in antimicrobial resistance, and it has been identified as an ESKAPE along with other extremely significant multidrug resistance pathogens. The present study was carried out to explore prevalence, antibiotic susceptibility phenotypes, virulence-associated genes, integron (int1), colistin (mcr-1), and β-lactamase resistance' genes (ESBls), as well as biofilm profiling of P. aeruginosa isolated from broiler chicks and dead in-shell chicks.DesignA total of 300 samples from broiler chicks (n = 200) and dead in-shell chicks (n = 100) collected from different farms and hatcheries located at Mansoura, Dakahlia Governorate, Egypt were included in this study. Bacteriological examination was performed by cultivation of the samples on the surface of both Cetrimide and MacConkey’s agar. Presumptive colonies were then subjected to biochemical tests and Polymerase Chain Reaction (PCR) targeting 16S rRNA. The recovered isolates were tested for the presence of three selected virulence-associated genes (lasB, toxA, and exoS). Furthermore, the retrieved isolates were subjected to phenotypic antimicrobial susceptibility testing by Kirby–Bauer disc diffusion method as well as phenotypic detection of ESBLs by both Double Disc Synergy Test (DDST) and the Phenotypic Confirmatory Disc Diffusion Test (PCDDT). P. aeruginosa isolates were then tested for the presence of antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, OXA-2, VEB-1, SHV, TEM, and CTX-M). Additionally, biofilm production was examined by the Tube Adherent method (TA) and Microtiter Plate assay (MTP).ResultsFifty –five isolates were confirmed to be P. aeruginosa, including 35 isolates from broiler chicks and 20 isolates from dead in-shell chicks. The three tested virulence genes (lasB, toxA, and exoS) were detected in all isolates. Antibiogram results showed complete resistance against penicillin, amoxicillin, ceftriaxone, ceftazidime, streptomycin, erythromycin, spectinomycin, and doxycycline, while a higher sensitivity was observed against meropenem, imipenem, colistin sulfate, ciprofloxacin, and gentamicin. ESBL production was confirmed in 12 (21.8%) and 15 (27.3%) isolates by DDST and PCDDT, respectively. Antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, SHV, TEM, and CTX-M), were detected in 87.3%, 18.2%, 16.4%, 69.1%, 72.7%, and 54.5% of the examined isolates respectively, whereas no isolate harbored the OXA-2 or VEB-1 genes. Based on the results of both methods used for detection of biofilm formation, Kappa statistics [kappa 0.324] revealed a poor agreement between both methods.Conclusionsthe emergence of mcr-1 and its coexistence with other resistance genes such as β-lactamase genes, particularly blaOXA-10, for the first time in P. aeruginosa from young broiler chicks and dead in-shell chicks in Egypt pose a risk not only to the poultry industry but also to public health.Graphical

In Situ Cas12a-Based Allele-Specific PCR for Imaging Single-Nucleotide Variations in Foodborne Pathogenic Bacteria.

In situ profiling of single-nucleotide variations (SNVs) can elucidate drug-resistant genotypes with single-cell resolution. The capacity to directly "see" genetic information is crucial for investigating the relationship between mutated genes and phenotypes. Fluorescence in situ hybridization serves as a canonical tool for genetic imaging; however, it cannot detect subtle sequence alteration including SNVs. Herein, we develop an in situ Cas12a-based amplification refractory mutation system-PCR (ARMS-PCR) method that allows the visualization of SNVs related to quinolone resistance inside cells. The capacity of discriminating SNVs is enhanced by incorporating optimized mismatched bases in the allele-specific primers, thus allowing to specifically amplify quinolone-resistant related genes. After in situ ARMS-PCR, we employed a modified Cas12a/CRISPR RNA to tag the amplicon, thereby enabling specific binding of fluorophore-labeled DNA probes. The method allows to precisely quantify quinolone-resistant Salmonella enterica in the bacterial mixture. Utilizing this method, we investigated the survival competition capacity of quinolone-resistant and quinolone-sensitive bacteria toward antimicrobial peptides and indicated the enrichment of quinolone-resistant bacteria under colistin sulfate stress. The in situ Cas12a-based ARMS-PCR method holds the potential for profiling cellular phenotypes and gene regulation with single-nucleotide resolution at the single-cell level.

Protective effects of naringin on colistin-induced damage in rat testicular tissue: Modulating the levels of Nrf-2/HO-1, AKT-2/FOXO1A, Bax/Bcl2/Caspase-3, and Beclin-1/LC3A/LC3B signaling pathways.

Antimicrobial agent resistance has become a growing health issue across the world. Colistin (COL) is one of the drugs used in the treatment of multidrug-resistant bacteria resulting in toxic effects. Naringin (NRG), a natural flavonoid, has come to the fore as its antioxidant, anti-inflammatory, and antiapoptotic activities. The aim of the present study was to determine whether NRG has protective effects on COL-induced toxicity in testicular tissue. Thirty-five male Spraque rats were randomly divided into five groups (n = 7 per group): Control, COL, NRG, COL + NRG 50, COL + NRG 100. COL (15 mg/kg b.w., i.p., once per/day), and NRG (50or 100 mg/kg, oral, b.w./once per/day) were administered for 7 days. The parameters of oxidative stress, inflammation, apoptosis, and autophagic damage were evaluated by using biochemical, molecular, western blot, and histological methods in testicular issues. NRG treatment reversed the increased malondialdehyde level and reduced antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione) levels due to COL administration (p < 0.001), and oxidative stress damage was mitigated. Nuclear factor erythroid 2-related factor-2 pathway, one of the antioxidant defence systems, was stimulated by NRG (p < 0.001). NRG treatment reduced the levels of markers for the pathways of apoptotic (p < 0.001) and autophagic (p < 0.001) damages induced by COL. Sperm viability and the live/dead ratio were reduced by COL but enhanced by NRG treatment. Testicular tissue integrity was damaged by COL but showed a tendency to improve by NRG. In conclusion, COL exhibited toxic effect on testicular tissue by elevating the levels of oxidative stress, apoptosis, autophagy, inflammation, and tissue damage. NRG demonstrated a protective effect by alleviating toxic damage.

Simultaneous determination of colistin sulfate and tigecycline in human plasma by liquid chromatography-tandem mass spectrometry method

ObjectiveTo establish a high-performance liquid chromatography–tandem mass spectrometry method (HPLC–MS/MS) to simultaneously determine colistin sulfate and tigecycline in human plasma.MethodsPolymyxin B1 internal standard (20 µL) was added into 200 µL of plasma sample. The samples were treated with methanol-5% trichloroacetic acid (50:50, V/V) solution, and the protein precipitation method was adopted for post-injection analysis. The chromatographic column was a Dikma C18 (4.6 mm × 150 mm, 5 μm). For the mobile phase, 0.1% formic acid in aqueous solution was used for phase A, 0.1% formic acid in acetonitrile solution for phase B, and gradient elution was also applied. The flow rate was 0.8 mL/min, the column temperature was 40 °C, and the injection volume was 10 µL; Electrospray ionization and multiple reaction ion monitoring were adopted and scanned by the HPLC–MS/MS positive ion mode.ResultsThe endogenous impurities in the plasma had no interference in the determination of the analytes. There existed a good linear relationship of colistin sulfate within the range of 0.1–10 µg/mL (R2 = 0.9986), with the lower limit of quantification (LLOQ) of 0.1 µg/mL. There existed a good linear relationship of tigecycline within the range of 0.05–5 µg/ mL (R2 = 0.9987), with the LLOQ of 0.05 µg/mL. The intra- and inter-day relative standard deviations of colistin sulfate and tigecycline were both less than 15%, and the accuracy was between 88.21% and 108.24%. The extraction had good stability, the extraction recovery rate was 87.75–91.22%, and the matrix effect was 99.40–105.26%.ConclusionThis study successfully established a method for simultaneously detecting colistin sulfate and tigecycline plasma concentrations. The method was simple, rapid, and highly sensitive and could be applied for therapeutic medication monitoring.

Antimicrobial resistance profiles of Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae strains isolated from broiler chickens

Globally, the spread of multidrug-resistant Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae from food to humans poses a severe threat to public health. The aim of this study was to assess the co-occurrence of colistin and β-lactamase resistance genes in E. coli, K. pneumoniae, and P. aeruginosa strains isolated from faeces of abattoir broiler chickens. The E. coli, P. aeruginosa and K. pneumoniae isolates were successfully detected from faecal samples by polymerase chain reaction (PCR) at infection rates of 60.7%, 22.5% and 16.7% respectively. The isolates displayed the highest levels of antibiotic resistance (AR) against ampicillin (82.3%) and amoxicillin-clavulanic acid (74.2%) for E. coli, followed by cefoxitin (70.6%) for K. pneumoniae, whilst P. aeruginosa displayed 26.1% antibiotic resistance (AR) against both ampicillin and colistin sulphate. The colistin mcr-1 gene was harboured by 46.8%, 47.1% and 21.7%, E. coli, K. pneumonia and P. aeruginosa isolates respectively. Ten out of 62 (16.1%), 6/17 (35.3%), 4/23 (17.4%) isolates were phenotypically classified as ESBL E. coli, K. pneumoniae, and P. aeruginosa respectively. The ESBL-E. coli isolates respectively possessed blaCTX-M (60%), blaTEM (20%) and blaCTX-M-9 (10%) genes. The ESBL-K. pneumoniae harboured, blaCTX-M (50%), blaOXA (33%), blaCARB (17%), and blaCTX-M-9 (17%) genes respectively, whilst, P. aeruginosa isolates respectively carried blaTEM (75%), blaCTX-M (50%), blaOXA (25%) and blaCARB (25%) genes. Molecular analysis identified the blaCTX-Mβ-lactamase-encoding genes collectively from E. coli, P. aeruginosa, K. pneumoniae isolates. Colistin and β-lactamase genes were present in only 16.7%, 6.9%, and 2.9% of E. coli, K. pneumoniae, and P. aeruginosa isolates, respectively. A total of 17, 7 and 3 isolates for E. coli, K. pneumoniae and P. aeruginosa respectively carried both colistin and β-lactamase antibiotics resistant genes. This is a public health threat that points to a challenge in the treatment of infections caused by these zoonotic bacteria. Data generated from this study will contribute to formulation of new strategies for combating spread of E. coli, K. pneumoniae, and P. aeruginosa isolates as well as prevention of their AR development.

Determining Susceptibility and Potential Mediators of Resistance for the Novel Polymyxin Derivative, SPR206, in Acinetobacter baumannii.

With the increase in carbapenem-resistant A. baumannii (CRAB) infections, there has been a resurgence in the use of polymyxins, specifically colistin (COL). Since the reintroduction of COL-based regimens in treating CRAB infections, several COL-resistant A. baumannii isolates have been identified, with the mechanism of resistance heavily linked with the loss of the lipopolysaccharide (LPS) layer of the bacterial outer membrane through mutations in lpxACD genes or the pmrCAB operon. SPR206, a novel polymyxin derivative, has exhibited robust activity against multidrug-resistant (MDR) A. baumannii. However, there is a dearth of knowledge regarding its efficacy in comparison with other A. baumannii-active therapeutics and whether traditional polymyxin (COL) mediators of A. baumannii resistance also translate to reduced SPR206 activity. Here, we conducted susceptibility testing using broth microdilution on 30 A. baumannii isolates (17 COL-resistant and 27 CRAB), selected 14 COL-resistant isolates for genomic sequencing analysis, and performed time-kill analyses on four COL-resistant isolates. In susceptibility testing, SPR206 demonstrated a lower range of minimum inhibitory concentrations (MICs) compared with COL, with a four-fold difference observed in MIC50 values. Mutations in lpxACD and/or pmrA and pmrB genes were detected in each of the 14 COL-resistant isolates; however, SPR206 maintained MICs ≤ 2 mg/L for 9/14 (64%) of the isolates. Finally, SPR206-based combination regimens exhibited increased synergistic and bactericidal activity compared with COL-based combination regimens irrespective of the multiple resistance genes detected. The results of this study highlight the potential utility of SPR206 in the treatment of COL-resistant A. baumannii infections.

Molecular detection of Shiga toxin and extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates from sheep and goats.

The Shiga toxin (Stx)-producing Escherichia coli (STEC) have become important global public health concerns. This study investigated the prevalence, antimicrobial resistance profile, and extended-spectrum beta-lactamase-producing E. coli in sheep and goat faeces. A total of 53 E. coli isolates were confirmed by PCR targeting the uidA [β-D glucuronidase] gene. The Shiga toxin genes stx1 and stx2, as well as bfpA, vir, eaeA, lt and aafII virulence genes, were detected in this study. Of the 53 isolates confirmed to be STEC, 100% were positive for stx2 and 47.2% for stx1. Three isolates possessed a combination of stx1 + stx2 + eaeA, while four isolates harboured stx1 + stx2 + vir virulence genes. The isolates displayed phenotypic antimicrobial resistance against erythromycin (66.04%), colistin sulphate (43.4%), chloramphenicol (9.4%) and ciprofloxacin (1.9%). A total of 28.8% of the strains were phenotypically considered ESBL producers and contained the beta-lactamase blaCTX-M-9 and blaCTX-M-25 gene groups. A larger proportion of the E. coli strains (86.8%) contained the antibiotic sulphonamide resistant (sulII) gene, while 62.3%, 62.3%, 52.8%, 43.4%, 41.5%, 20.8%, 18.9%, 11.3%, 11.3%, 9.4%, 9.4% and 5.7% possessed mcr-4, floR, mcr-1, tet(A), sulI, tet(O), tet(W), parC, mcr-2, ampC 5, qnrS and ermB genes, respectively. Thirteen isolates of the ESBL-producing E. coli were considered multi-drug resistant (MDR). One Shiga toxin (stx2) and two beta-lactamase genes (blaCTX-M-9 and blaCTX-M-25 groups) were present in 16 isolates. In conclusion, the E. coli isolates from the small stock in this study contained a large array of high antibiotic resistance and virulence profiles. Our findings highlight the importance of sheep and goats as sources of virulence genes and MDR E. coli. From a public health and veterinary medicine perspective, the characterization of ESBL producers originating from small livestock (sheep and goats) is crucial due to their close contact with humans.

ИЗУЧЕНИЕ ФАРМАКОКИНЕТИКИ ДЕЙСТВУЮЩИХ ВЕЩЕСТВ ПРЕПАРАТА «ДОКСИКОЛИВЕТ» И «ТИЛМИКОЗИН» У ЦЫПЛЯТ - БРОЙЛЕРОВ

The aim of the study was to determine the amount of residual substances of the drug "Doxicolivet" and Tilmicosin 25% in poultry products by high-performance liquid chromatography in dynamics. The objects of the study were 10 heads of broiler chickens, live weight 500 g, 15 days old. The drugs used to assess the residual amount of active substances were the complex antibacterial drug Doxicolivet, as well as the mono-drug Tilmicosin 25%. In this work, the method of high-performance liquid chromatography (HPLC) was used to determine the residual amount of active substances of the drugs in question in poultry products. The total residual substances in the tissues were determined using a scintillation counter, and the residual content of tilmicosin phosphate and colistin sulfate was determined using high-performance liquid chromatography on an Agilent 1220 Infinity II chromatograph (Agilent Technologies Inc., USA). In this work, only the residual amount of doxycycline – hyclate, which is part of the complex broad-spectrum antibacterial drug Doxicolivet, was determined, since colistin sulfate is not absorbed in the gastrointestinal tract and does not accumulate in the muscle, adipose tissues and parenchymal organs of birds. Studies conducted on the residual amounts of active substances of the studied drugs: Tilmicosin 25% and Doxicolivet in broiler chickens, 15 days old, live weight 500 g., with their oral (with water) use showed that components of the antibacterial agents in question are present in both muscle and adipose tissue: Tilmicosin 25%" and "Doxicolivet" even 96 hours after the last evaporation in both muscle tissue and adipose tissue, 21 mcg/kg and 39 mcg/kg, respectively. The limit of quantitative determination of the components of the drug was reached only by 192 hours. Thus, the slaughter of broiler chickens after the use of Tilmicosin 25% and Doxicolivet drugs is possible only after 192 hours.

Clinical Efficacy and Safety of Colistin Sulfate in the Treatment of Carbapenem-Resistant Organism Infections in Patients with Hematological Diseases.

Carbapenem-resistant organisms (CRO) have emerged as a significant worldwide issue. However, the availability of efficacious antibiotics for treating CRO infections remains limited. Polymyxins, including colistin sulfate, represent the last-line therapeutic option against CRO infections. This study aims to retrospectively evaluate the clinical effectiveness and safety of colistin sulfate in managing CRO infections among patients with hematological diseases. Between April 2022 and January 2023, a total of 118 hematological patients diagnosed with CRO infection were treated with colistin sulfate at Suzhou Hongci Hospital of Hematology. The assessment encompassed the clinical efficacy, bacterial clearance rate, adverse reactions, and 30-day all-cause mortality. The study found that the total effective rate of colistin sulfate in the treatment of CRO infection was 74.6%, with a bacterial clearance rate of 72.6%. Throughout the treatment, nephrotoxicity occurred in 7.6% of cases, neurotoxicity in 2.5% of cases, and the 30-day all-cause mortality rate was 22.9%. Multivariate logistic analysis revealed that the treatment course and combination medication with other antimicrobials were independent factors affecting the clinical efficacy of colistin sulfate. Our study demonstrates that the treatment of colistin sulfate can achieve high clinical efficacy and microbial responses, with a low risk of nephrotoxicity. This study provides evidence of the positive clinical efficacy and safety of colistin sulfate treatment in these patients. High-quality randomized controlled trials are still needed to further confirm the beneficial role of colistin sulfate.

Evaluation of the probiotic potential of yeast isolated from kombucha in New Zealand

The current study investigated the in vitro probiotic potential of yeast isolated from kombucha, a tea beverage fermented with a symbiotic culture of acetic acid bacteria and yeast. A total of 62 yeast strains were previously isolated from four different commercial kombucha samples sold in New Zealand. Fifteen representative isolates belonging to eight different species were evaluated for their growth under different conditions (temperature, low pH, concentrations of bile salts, and NaCl). Cell surface characteristics, functional and enzymatic activities of the selected strains were also studied in triplicate experiments. Results showed that six strains (Dekkera bruxellensis LBY1, Sachizosaccharomyces pombe LBY5, Hanseniaspora valbyensis DOY1, Brettanomyces anomalus DOY8, Pichia kudraivzevii GBY1, and Saccharomyces cerevisiae GBY2) were able to grow under low-acid conditions (at pH 2 and pH 3) and in the presence of bile salts. This suggests their potential to survive passage through the human gut. All 15 strains exhibited negative enzymatic activity reactions (haemolytic, gelatinase, phospholipase, and protease activities), and thus, they can be considered safe to consume. Notably, two of the fifteen strains (Pichia kudraivzevii GBY1 and Saccharomyces cerevisiae GBY2) exhibited desirable cell surface hydrophobicity (64.60–83.87%), auto-aggregation (>98%), co-aggregation, resistance to eight tested antibiotics (ampicillin, chloramphenicol, colistin sulphate, kanamycin, nalidixic acid, nitrofurantoin, streptomycin, and tetracycline), and high levels of antioxidant activities (>90%). Together, our data reveal the probiotic activities of two yeast strains GBY1 and GBY2 and their potential application in functional food production.

Diversity of Antibiotic-resistant of Tentative Motile Aeromonas Species Isolated From Clarias gariepinus (Burchell 1822) Cultured in Earthen Ponds

Background: Aeromonas species is one of the most important causes of diseases in Clarias gariepinus, a public health threat with significant economic losses. Objectives: In this research, the prevalence and variety of Aeromonas species isolated from C. gariepinus cultured in an earthen pond were investigated, as well as the antibiogram and multiple antibiotic resistance index Methods: Aeromonas species were isolated by culture and biochemical test and confirmed using a Microbact 24E kit. The antibiotic susceptibility to 10 antibiotics was determined using the Kirby-Bauer disk diffusion method. Results: Aeromonas species were isolated with a prevalence of 43.1% with 4 different phenospecies with the highest prevalence of 46(24 %) for Aeromonas hydrophila followed by 15(7.8%) for Aeromonas caviae, then 10(5.2%) for Aeromonas veronii sobria, and the least was observed for Aeromonas veronii veronii 6(3.1%). The Aeromonas species showed high resistance to amoxicillin, ampicillin, colistin sulfate, oxytetracycline, trimethoprim/sulfamethoxazole, and penicillin, with varying resistant patterns, and the multiple antibiotic resistance index values ranged between 0.20 and 0.80. Conclusion: There was a diversity of Aeromonas species associated with multiple antibiotic-resistant leading to the wide spread of antimicrobial resistance. Therefore, there is a need to control the use of antibiotics and ensure the effective use of biosecurity and preventive management measures in fish farms.

First detection and characterization of mcr-1 colistin resistant E. coli from wild rat in Bangladesh.

Colistin resistance is a global concern warning for a one health approach to combat the challenge. Colistin resistant E. coli and their resistance determinants are widely distributed in the environment, and rats could be a potential source of these isolates and resistant determinants to a diverse environmental setting. This study was aimed to determine the presence of colistin resistant E. coli (CREC) in wild rats, their antimicrobial resistance (AMR) phenotypes, and genotypic analysis of mcr-1 CREC through whole genome sequencing (WGS). A total of 39 rats were examined and CREC was isolated from their fecal pellets onto MacConkey agar containing colistin sulfate (1 μg/ mL). AMR of the CREC was determined by disc diffusion and broth microdilution was employed to determine MIC to colistin sulfate. CREC were screened for mcr genes (mcr-1 to mcr-8) and phylogenetic grouping by PCR. Finally, WGS of one mcr-1 CREC was performed to explore its genetic characteristics especially resistomes and virulence determinants. 43.59% of the rats carried CREC with one (2.56%) of them carrying CREC with mcr-1 gene among the mcr genes examined. Examination of seventeen (17) isolates from the CREC positive rats (n = 17) revealed that majority of them belonging to the pathogenic phylogroup D (52.94%) and B2 (11.76%). 58.82% of the CREC were MDR on disc diffusion test. Shockingly, the mcr-1 CREC showed phenotypic resistance to 16 antimicrobials of 8 different classes and carried the ARGs in its genome. The mcr-1 gene was located on a 60 kb IncI2 plasmid. On the other hand, ARGs related to aminoglycosides, phenicols, sulfonamides, tetracyclines and trimethoprims were located on a 288 kb mega-plasmid separately. The mcr-1 CREC carried 58 virulence genes including genes related to adhesion, colonization, biofilm formation, hemolysis and immune-evasion. The isolate belonged to ST224 and closely related to E. coli from different sources including UPEC clinical isolates from human based on cgMLST analysis. The current research indicates that rats might be a possible source of CREC, and the presence of mcr-1 and other ARGs on plasmid increases the risk of ARGs spreading and endangering human health and other environmental components through this infamous pest.

High qnrS retention of ESBL-producing and mcr-harbouring colistin-resistant Escherichia coli in Vietnamese food products.

Plasmid-mediated antibiotic-resistant bacteria's transmission is fatal and a major threat to public health. This study aimed to clarify the presence of plasmid-mediated quinolone resistance（PMQR）genes in extended-spectrum β-lactamase（ESBL）-producing or/and mcr-harbouring colistin（COL）-resistant Escherichia coli（ESBL-COL-EC）isolates from Vietnamese and Japanese chicken meat. Resistance towards ciprofloxacin（CIP）was examined in 308 ESBL-COL-EC isolates; CIP-resistant ESBL-COL-EC isolates were examined for the PMQR gene. Approximately, 71.1% and 38.1% of ESBL-COL-EC and ESBLproducing E. coli isolates from Vietnamese and Japanese chicken meat were CIP-resistant, respectively. Multiplex PCR led PMQR detection showed that 35.2% of CIP-resistant ESBL-COL-EC isolates from Vietnamese food contained PMQR gene, whereas CIP-resistant ESBL-COL-EC isolates from Japanese chicken meat did not. Conjugation assays showed that the transmission of qnrS gene carried by E. coli to Salmonella. In conclusion, ESBL-COL-EC isolates from Vietnamese food are associated with a high frequency of fluoroquinolone resistance and a high distribution of the qnrS gene.

Transcriptional responses of cytokines, immunoglobulin A, and nitric oxide genes in 1-day-old chicks post Salmonella typhimurium infection: An experimental study.

Salmonella has become one of the hazards prevalent foodborne pathogens causing different diseases in chickens. However, Salmonella typhimurium (ST), a nonhost-specific serovar, is a major avian agent that causes severe disturbance in young chicken wellness. The occurrence of Salmonella in chickens and their antimicrobial resistance were explored in this study. In addition, the immune response of 1-day-old broiler chicks, against multidrug resistant (MDR) ST infection, was also assessed at 4 and 24 hours post infection (pi) in the cecum and spleen, representing their mucosal and systemic immune responses, respectively. A total of 375 samples from 130 diseased and apparently healthy broiler and layer chickens were randomly collected for Salmonella isolation, identification, and resistance profile evaluation, from farms and different clinical laboratories. The immune response of 1-day-old broiler chicks, Ross 308, against in-vivo ST infection was ascertained through the evaluation of heterophile phagocytosis and s expression of cytokines, immunoglobulin A and other immune-regulating genes in the cecum and spleen. Twenty-four, 1-day-old nonvaccinated broiler chicks were used and divided into two groups. The chicks in the infected group were orally inoculated with 0.5 ml of 2 × 108 colony forming units (CFU)/ml of MDR ST suspension, while those in the control group were taken nutrient broth. Seven out of 130 (5.38%) examined chickens were positive for Salmonella. All isolates (100%) were resistant to amoxicillin-clavulanic acid (AMC), cefazolin (CZ), cefoxitin (FOX), ciprofloxacin (CIP), nalidixic acid (NA), tetracycline (TE), fosfomycin (FOS), and colistin (CT) with multiple antimicrobial resistances (MARs) index range of 0.72-0.83, where none of them was resistant to meropenem (MEM). The results of immune response revealed that chicks infected with ST showed significantly different phagocytosis percentages and index values compared to controls. According to the real-time quantitative polymerase chain reaction (RT-qPCR) results, the transcription of IL-8, iNOS, IL-18, IgA, and IFN-γ for chicks infected by ST showed a significantly increased trend (p < 0.01) with increasing chicken age and was higher in the cecum than spleen compared to controls (p < 0.05) during 24 hours after infection. The findings indicated a strong mucosal immune response in the chicks after the ST challenge, which reflects humoral and cellular responses. Our insight recommended the occurrence of a natural immune response stimulator at 1 day age to face the infection, and this can prevent the resistance transfer, with efficient control measures.

Coronavirus infection and systemic inflammatory reaction syndrome.

Aim: The purpose of this study was a clinical approbation of the Kometad drug (international non-proprietary name sodium colistimethate), an antibiotic from the polymyxin group in patients with severe course of confirmed сoronavirus infection in the intensive care unit of the Branch of the I. Zhekenova Municipal Clinical Infectious Diseases Hospital.. Materials and Methods: The methodology is based on both theoretical and empirical methods of scientific cognition. During the study, the features of the Coronavirus infection and the inflammatory reaction syndrome were considered, which became quite a big problem during the pandemic. Results: The main indications for the tested drug and the consequences of its use for one age group were also determined. Conclusions: The conclusion was made about the positive dynamics of the patients' health status, and recommendations were given for further research in this area. The practical significance of this study lies in the first clinical approbation of the Kometad drug, which can be used in medicine to reduce the severity of the systemic inflammatory reaction syndrome and improve the patient's health as a result of the disease of Coronavirus infection, after further clinical trials of the drug with different age groups of patients.

Whole genome sequencing of resistance and virulence genes in multi-drug resistant Pseudomonas aeruginosa

BackgroundPseudomonas aeruginosa is an opportunistic bacterium that causes serious hospital-acquired infections. To assess the risk of clinically isolated P. aeruginosa to human health, we analyzed the resistance and virulence mechanisms of a collection of clinical isolates. MethodsThis was a retrospective study in which P. aeruginosa isolates collected from January 1, 2018 to August 31, 2019 were analyzed using phenotypic and whole-genome sequencing (WGS) methods. The analysis included 48 clinical samples. Median patient age was 54.0 (29.5) years, and 58.3% of patients were women. Data from the microbiology laboratory database were reviewed to identify P. aeruginosa isolates. All unique isolates available for further testing were included, and related clinical data were collected. Infections were defined as hospital acquired if the index culture was obtained at least 48 h after hospitalization. ResultsHigh-risk P. aeruginosa clones, including sequence types (STs) ST235 and ST111, were identified, in addition to 12 new STs. The isolates showed varying degrees of biofilm formation ability when evaluated at room temperature, along with reduced metabolic activity, as measured by metabolic staining, suggesting their ability to evade antimicrobial therapy. Most isolates (77.1%) were multidrug resistant (MDR), with the highest resistance and susceptibility rates to beta-lactams and colistimethate sodium, respectively. ConclusionsThe MDR phenotypes of the examined isolates can be explained by the high prevalence of efflux-mediated resistance- and hydrolytic enzyme-encoding genes. These isolates had high cytotoxic potential, as indicated by the detection of toxin production-related genes.

Anionic Hyperbranched Amphiphilic Polyelectrolytes as Nanocarriers for Antimicrobial Proteins and Peptides.

This manuscript presents the synthesis of hyperbranched amphiphilic poly (lauryl methacrylate-co-tert-butyl methacrylate-co-methacrylic acid), H-P(LMA-co-tBMA-co-MAA) copolymers via reversible addition fragmentation chain transfer (RAFT) copolymerization of tBMA and LMA, and their post-polymerization modification to anionic amphiphilic polyelectrolytes. The focus is on investigating whether the combination of the hydrophobic characters of LMA and tBMA segments, as well as the polyelectrolyte and hydrophilic properties of MAA segments, both distributed within a unique hyperbranched polymer chain topology, would result in intriguing, branched copolymers with the potential to be applied in nanomedicine. Therefore, we studied the self-assembly behavior of these copolymers in aqueous media, as well as their ability to form complexes with cationic proteins, namely lysozyme (LYZ) and polymyxin (PMX). Various physicochemical characterization techniques, including size exclusion chromatography (SEC) and proton nuclear magnetic resonance (1H-NMR), verified the molecular characteristics of these well-defined copolymers, whereas light scattering and fluorescence spectroscopy techniques revealed promising nanoparticle (NP) self- and co-assembly properties of the copolymers in aqueous media.

Association Between the Site of Infection and Mortality Analysis in Critically Ill Surgical Patients.

Background Sepsis remains a critical global health concern, leading to a high mortality rate. Existing literature suggests a potential correlation between infection site and mortality. Mortality data from Pakistan, especially in the context of the infection site, is notably scarce. Purpose The study aimed to explore the relationship between the site of infection and clinical features in deceased septic patients in the surgical intensive care unit. Methods In this retrospective study conducted at the Aga Khan University Hospital, data from patients admitted to the surgical intensive care unit and meeting Sepsis 3 criteria over a five-year period (2016-2020) were analyzed. We analyzed the relation between the infection site and clinical characteristics using analysis of variance (ANOVA), chi-square, or Fisher's exact tests. Multivariable logistic regression models were applied using stepwise forward selection. A p-value of ≤ 0.05 was considered statistically significant. Results A total of 2472 ICU admissions were screened, out of which 170 patients were included in this study. Demographic analysis showed a predominantly male population with a mean age of 47 years. The most prevalent site of infection was the abdomen. Logistic regression analysis identified on-admission septic shock and highAcute Physiology and Chronic Health Evaluation (APACHE) II scores as significant risk factors for 48-hour mortalitywhile colistimethate sodium usage and admission through the operating room were protective. Conclusion Our study provides a comprehensive analysis, outlining infection sites and identifying early mortality-influencing factors within our region. The distinct demographic profile, characterized by younger age, and the prevalence of abdominal infections in the Pakistani cohort contradict established medical literature. Early initiation of broad-spectrum antibiotics, coupled with prompt source control, confers a protective effect upon individuals afflicted with sepsis.