Different Classes Of Antibiotics Research Articles

Aromatic hydrazides: A potential solution for Acinetobacter baumannii infections

The emergence of multidrug-resistant bacteria and the poor efficacy of available antibiotics against these infections have led to the urgent need for novel antibiotics. Acinetobacter baumannii is one of high-priority pathogens due to its ability to mount resistance to different classes of antibiotics. In an effort to provide novel agents in the fight against infections caused by A. baumannii, we synthesized a series of 46 aromatic hydrazides as potential treatments. In this series, 34 compounds were found to be low- to sub-μM inhibitors of A. baumannii growth, with MIC values in the range of 8 μg/mL to ≤0.125 μg/mL against a broad set of multidrug-resistant clinical isolates. These compounds were not highly active against other bacteria. We showed that one of the most potent compounds, 3e, was bacteriostatic and inhibitory to biofilm formation, although it did not disrupt the preformed biofilm. Additionally, we found that these compounds lacked mammalian cytotoxicity. The high antibacterial potency and the lack of mammalian cytotoxicity make these compounds a promising lead series for development of a novel selective anti-A. baumannii antibiotic.

Antibacterial Activity of Peptide Derivatives of Phosphinothricin against Multidrug-Resistant Klebsiella pneumoniae.

The fast spread of bacteria that are resistant to many classes of antibiotics (multidrug resistant) is a global threat to human and animal health with a worrisome scenario ahead. Novel therapeutical strategies are of crucial importance to combat this phenomenon. For this purpose, we investigated the antimicrobial properties of the naturally occurring tripeptide Bialaphos and a dipeptide L-leucyl-L-phosphinoithricin, the synthesis and diastereomers separation of which are herein described. We demonstrate that these compounds are effective on clinical isolates of the human pathogen Klebsiella pneumoniae, causing hospital-acquired and community-acquired infections. The tested isolates were remarkable for their resistance to more than 20 commercial antibiotics of different classes. Based on previous literature data and our experiments consisting of glutamine supplementation, we suggest that both compounds release phosphinothricin-a well-known nanomolar inhibitor of glutamine synthetase-after their penetration in the bacterial cells; and, in this way, exert their antibacterial effect by negatively affecting nitrogen assimilation in this pathogen.

Multiresidues Multiclass Analytical Methods for Determination of Antibiotics in Animal Origin Food: A Critical Analysis

Veterinary drugs are widely used to prevent and treat diseases. The European Union has forbidden the use of antibiotics as growth promoters since 2006. Its abusive use leads to the presence of antibiotic residues (AR) in foods of animal origin which is associated with antibiotic resistance. The monitoring of AR in food intended for human consumption is of utmost importance to assure Food Safety. A systematic bibliographic review was carried out on the analytical methodologies, published in 2013, for the determination of AR in foods of animal origin. The food processing effect in the AR detected in animal products is also addressed. However, there is a preference for multiresidues multiclass methods, i.e., methodologies that allow determining simultaneously different classes of antibiotics, which is still a challenge for researchers. The wide diversity of physico-chemical properties of these drugs is an obstacle to achieving excellent analytical performance for a vast number of molecules analyzed concurrently. New techniques in sample preparation continue to be developed in order to obtain a compromise between good recoveries and extracts without interferences (clean extracts). The most widely used analytical methodology for the determination of AR is liquid chromatography coupled with mass spectrometry. However, the current trend is focused on the use of powerful high-resolution MS detectors such as Time of Flight and Orbitrap with modern chromatographic systems. Cooking time and temperature control are the key processing conditions influencing the reduction of AR in foods.

Antibiotics resistance pattern of Pseudomonas aeruginosa isolated from different hospitals in Nowshera KPK Pakistan

Pseudomonas aeruginosa is an invasive nosocomial pathogen of immunocompromised individuals that mainly affects the respiratory system, urinary tract, burns, and wounds, as well as blood diseases. In this investigation, samples from pus, wound swabs, sputum, blood, and urine were collected to examine the isolation, biochemical identification, and antibiotic resistance pattern against antibiotics of Pseudomonas aeruginosa in Qazi Medical Complex (QMC) and District Headquarter Hospital (DHQ) Nowshera, KPK Pakistan. For biochemical identification, the catalase, oxidase, triple sugar iron, and citrate utilisation tests were run. Using the Kirby Bauer Disc diffusion technique, antibiotic resistance was revealed. Pseudomonas aeruginosa was most prevalent in group C males (51-100 years old) and group B females (60.7%), (19-50 ages). The Clinical samples were divided as follows: pus (40.6%), urine (16.2%), sputum (16.2%), sputum (10.5%), wound (4.8%) and blood (3.2%). According to the antimicrobial resistance pattern, from 6 antibiotics of different classes, Ceftazidime (90%) and cefotaxime (86%) showed high resistance. In contrast, Meropenem (12%), Levofloxacin (16%), and Ciprofloxacin (24%) showed sensitivity, and Gentamicin (30%) was intermediate against P. aeruginosa. Our outcome specifies that P. aeruginosa was highly resistant to some commonly prescribed antibiotics. The selection and reasonable application of antimicrobial drugs in hospital settings for first therapy would be beneficial in preventing the further spread of resistance as the incidence of isolates of P. aeruginosa raises over time.

PATHOGENIC BACTERIAL ISOLATES FROM DIABETIC FOOT INFECTIONS PATIENTS AND THEIR SUSCEPTIBILITY TO ANTIBIOTICS IN SELECTED PUBLIC HOSPITALS, SANA’A, YEMEN

Sickle cell disease (SCD) is a group of blood genetic disorders resulting in an abnormality in the Diabetic foot infections remain a major public health problem and cause socioeconomic burdens to affected people. Clinically infected foot ulcers require treatment guided by appropriate cultures and antimicrobial susceptibility testing. This study aimed to assess the bacterial profile and antimicrobial susceptibility pattern of isolates from diabetic foot infections in selected public hospitals, Sana'a, Yemen. A cross-sectional study was conducted from June 2021 to July 2022 at Al-Gomhori teaching hospital, Kuwait teaching hospital, and AlThawrah public hospital in Sana'a, the capital city of Yemen. The study included 135 adult patients with infected diabetic foot ulcers. Convenient sampling was employed. Wound aspirates from the foot ulcers were collected aseptically and inoculated into Blood, MacConkey, Chocolate and Mannitol salt Agar. The antimicrobial susceptibility patterns were conducted by disk diffusion method. The data was analyzed with SPSS v.20 for windows. The results revealed that; One hundred ninety bacterial isolates were identified among 135 patients. Among them, 62.96% had mono-bacterial infection while 37.04% had mixed bacterial infections. Gram negative aerobic bacterial infections were more accounting cases 63.7% than, Gram positive aerobic bacteria 36.3%. The most commonly isolated bacteria were S. aureus 26.3%, followed by Klebsiella spp 22.1% and Proteus spp 11.1%. In general, 73.68% of the isolates developed multidrug resistance to at least one drug in three different classes of antibiotics. Meropinem and amikacin appeared to be the best antibiotics for therapy against Gram negative and cefoxitin and vancomycin against Gram positive organisms.

The significant role of Carbapenems-resistant Acinetobacter Baumannii in mortality rate of patients with COVID-19

Background: Infections caused by Acinetobacter baumannii, especially carbapenem-resistant (CR) strains, pose important challenges in patients with COVID-19 infection. Therefore, in the present study, we investigated co-infection and antimicrobial resistance patterns, as well as the role of A. baumannii in the outcome of patients with COVID-19.Materials and methods: Between February 2019 and January 2021, 141 patients with A. baumannii infections were detected from seven different hospitals (A to G) in Arak, Iran, and the antibacterial susceptibility pattern of these isolates was evaluated using disk diffusion and E-test methods. Forty-seven of these patients were co-infected with COVID-19. During the study, the data about the clinical course, demographic data, and the role of A. baumannii infections in the mortality rate of COVID-19 patients were collected.Results: Hospitals A and B reported the most patients, with 53 (38%) and 47 (33%), respectively. Additionally, most cases (105 cases, 75%) were reported from surgical and general ICUs. Mechanical ventilators were detected as predisposing factors in 95 (67%) patients, and infection was detected in 20% of patients on the 10th day after intubation. All of the A. baumannii isolates were resistant to different classes of antibiotics, such as carbapenems. Notably, 33% (47 patients) were also positive for COVID-19, and 68% (32 patients) died due to the infection. Statistical analysis showed a significant role of A. baumannii co-infection in the mortality rate of COVID-19 patients (p-value 0.05).Conclusion: co-infection with A. baumannii is one of the most important challenges in COVID-19 patients. Our results showed that all isolated bacteria were CR and significantly increased mortality rates in COVID-19 patients.

Characterization of Klebsiella pneumoniae isolated from Contaminated Sheep and Goat Meat at Matrouh Governorate and Its Antibiotic Resistance

The study of Klebsiella pneumoniae as a food born pathogen that isolated from sheep and goat meat at Matrouh Governorate, and tracking the extent of its resistance to various antibiotics, is considered the first study at Matrouh Governorate. Out of 48 meat samples, 6 (12.5%) were positive for Klebsiella pneumoniae subspecies pneumoniae by PCR. All Klebsiella pneumoniae isolates (100%) showed presence of fim H and aerobactin genes. All isolates showed resistance to at least 3 different classes of antibiotics, so, considered as multi drug resistant (MDR) or pan-drug resistant. The 2 pan-drug resistant strains were extended spectrum beta lactamase (ESBL) producers.

Phage-resistant mutations impact bacteria susceptibility to future phage infections and antibiotic response.

Bacteriophage (phage) therapy in combination with antibiotic treatment serves as a potential strategy to overcome the continued rise in antibiotic resistance across bacterial pathogens. Understanding the impacts of evolutionary and ecological processes to the phage-antibiotic-resistance dynamic could advance the development of such combinatorial therapy. We tested whether the acquisition of mutations conferring phage resistance may have antagonistically pleiotropic consequences for antibiotic resistance. First, to determine the robustness of phage resistance across different phage strains, we infected resistant Escherichia coli cultures with phage that were not previously encountered. We found that phage-resistant E. coli mutants that gained resistance to a single phage strain maintain resistance to other phages with overlapping adsorption methods. Mutations underlying the phage-resistant phenotype affects lipopolysaccharide (LPS) structure and/or synthesis. Because LPS is implicated in both phage infection and antibiotic response, we then determined whether phage-resistant trade-offs exist when challenged with different classes of antibiotics. We found that only 1 out of the 4 phage-resistant E. coli mutants yielded trade-offs between phage and antibiotic resistance. Surprisingly, when challenged with novobiocin, we uncovered evidence of synergistic pleiotropy for some mutants allowing for greater antibiotic resistance, even though antibiotic resistance was never selected for. Our results highlight the importance of understanding the role of selective pressures and pleiotropic interactions in the bacterial response to phage-antibiotic combinatorial therapy.

Exploring Oceans for Curative Compounds: Potential New Antimicrobial and Anti-Virulence Molecules against Pseudomonas aeruginosa.

Although several antibiotics are already widely used against a large number of pathogens, the discovery of new antimicrobial compounds with new mechanisms of action is critical today in order to overcome the spreading of antimicrobial resistance among pathogen bacteria. In this regard, marine organisms represent a potential source of a wide diversity of unique secondary metabolites produced as an adaptation strategy to survive in competitive and hostile environments. Among the multidrug-resistant Gram-negative bacteria, Pseudomonas aeruginosa is undoubtedly one of the most important species due to its high intrinsic resistance to different classes of antibiotics on the market and its ability to cause serious therapeutic problems. In the present review, we first discuss the general mechanisms involved in the antibiotic resistance of P. aeruginosa. Subsequently, we list the marine molecules identified up until now showing activity against P. aeruginosa, dividing them according to whether they act as antimicrobial or anti-virulence compounds.

1387. Prevalence and Risk Factors for Bacterial Resistance in Diabetic Foot Infections at a Hospital in Nicaragua.

Abstract Background The bacterial resistance could have an deleterious outcome in patients with diabetic foot infections (DFI). The aim of this study was to determine the prevalence, the main risk factors, and clinical outcomes for DFI caused by bacterias that were resistant to different classes of antimicrobials in a hospital in Nicaragua. Methods A case-control study was conducted between January 2019 and March 2020 at Hospital Dr. Fernando Vélez Paiz in Managua (Nicaragua). Cases were patients with diabetic foot infections caused by drug-resistant organisms (DRO) and the controls were patients infected by non-drug resistant organisms (NDRO). The resistance to quinolones, beta-lactams, and carbapenems were evaluated in the Gram negative bacterias. In the cases of Staphylococcus aureus the resistant to methicillin was evaluated. Samples of tissue and exudates obtained by aspiration were processed. Conventional methods as blood agar and McConkey agar were used, and the final identification method was Vytek 2 System. Different variables of both groups were compared. Results A total of 76 bacterias were identified in 61 patients. Forty-four patients had an infection with at least one resistant bacteria for a prevalence of 72%. Staphylococcus aureus was the most prevalent bacteria and 76.9% of them were resistant to methicillin (MRSA). A 71% of the Gram negative bacterias were resistant to at least one class of antibiotic; 58% of them were resistant to quinolones, 40% were ESBL positive, and 12% were resistant to carbapenems. A total of 12 isolates were multi-drug resistant organisms (MDRO). The main risk factor to have an infection with a resistant bacteria was the use of antibiotics into the previous 3 months (OR:4.28; CI95%: 1.31-13.98). An infection caused by DRO was associated with a increased risk of amputation. Infections caused by NDRO had more probability of clinical resolution (OR:0.14; CI95%:0.04-0.48). Prevalence of Resistant Bacterias to Different Classes of Antibiotics in Diabetic Foot Infections. Conclusion In this setting, the bacterial resistance in diabetic foot infections has to be considered significative. MRSA had a high prevalence and the Gram negative organisms showed an important resistance rate to different classes of antibiotics. The main risk factor was the previous use of antibiotics. The clinical outcome is affected by the bacterial resistance. Disclosures All Authors: No reported disclosures.

2048. Molecular Characterization and Resistance Factors of Circulating Acinetobacter baumannii isolates in South-East Michigan

Abstract Background Carbapenem-resistant Acinetobacter baumannii (CRAb) is increasing due to widespread use of antibiotics. Multidrug resistant (MDR) CRAb is a major threat to public health as treatment options are limited. The objective of this study is to elucidate the molecular epidemiology of circulating antibiotic resistance genes causing MDR CRAb infections by using a combination of whole-genome Multi-Locus Sequence Typing (wgMLST) and antibiotic susceptibility phenotyping. Table 1.Molecular characterization of MDR CRAb isolates*The numbers indicate % of sequence identity match for each Beta-lactamase gene. Methods Bacterial isolates were derived from cultures taken from subjects 48 hours following admission as part of routine clinical care for patients between 2017-2020. Isolates were obtained from 16 hospital units (both ICU and non-ICU) across two hospitals in the Detroit area. Whole Genome Sequencing (WGS) was performed using Illumina MiniSeq or Nextseq. WgMLST analysis was performed using BioNumerics software v7.6. ResFinder software was used for analysis of antibiotic resistance genes. Isolates underwent antibiotic susceptibility testing using a broth microdilution method (VITEK2) and Clinical & Laboratory Standards Institute (CLSI) minimum inhibitory concentration (MIC) cut offs. Results Out of the 95 total isolates, 51(54%) were CRAb isolates and of the CRAb isolates, 21(41%) were MDR CRAb. WgMLST identified that majority of the circulating MDR CRAb isolates belonged to ST2Pas (ST195Ox and ST208Ox) based on CDC definitions (Table 1). MDR CRAb isolates were resistant to 3 different classes of antibiotics including aminoglycosides, fluroquinolones and β-lactams. β-lactamase genes present include (blaADC-25, blaOXA-23, blaOXA-66 and blaTEM1D) for both ST195Ox and ST208Ox and (blaADC-25, blaOXA-23 and blaOXA-223) for ST406Pas (ST310Ox). Among the patients with MDR CRAb infections, most were males with respiratory infections in a non-ICU setting. Conclusion The study demonstrated a high proportion of isolates belonged to ST2 Pas carrying multiple beta-lactamase genes including blaOXA-23 gene. ST406Pas might be an emerging lineage carrying the blaOXA-23 gene. In addition to stringent infection control measures, continuous surveillance is recommended in limiting the spread of MDR CRAb isolates in the healthcare settings. Disclosures Chetan Jinadatha, MD, MPH, AHRQ R01 Grant-5R01HS025598: Grant/Research Support|EOS Surfaces: Copper Coupons and materials for testing Keith S. Kaye, MD, MPH, Allecra: Advisor/Consultant|GlaxoSmithKline plc.: Receiving symposia honoraria|GlaxoSmithKline plc.: GlaxoSmithKline plc.-sponsored study 212502|Merck: Advisor/Consultant|qpex: Advisor/Consultant|Shionogi: Grant/Research Support|Spero: Advisor/Consultant Piyali Chatterjee, PhD, AHRQ Grant # 1R03HS027667-01: Grant/Research Support|AHRQ Grant # 1R03HS027667-01: Central Texas Veterans Health Care System.

Occurrence and Genomic Characterization of mcr-1-Harboring Escherichia coli Isolates from Chicken and Pig Farms in Lima, Peru.

Resistance to colistin generated by the mcr-1 gene in Enterobacteriaceae is of great concern due to its efficient worldwide spread. Despite the fact that the Lima region has a third of the Peruvian population and more than half of the national pig and poultry production, there are no reports of the occurrence of the mcr-1 gene in Escherichia coli isolated from livestock. In the present work, we studied the occurrence of E. coli carrying the mcr-1 gene in chicken and pig farms in Lima between 2019 and 2020 and described the genomic context of the mcr-1 gene. We collected fecal samples from 15 farms in 4 provinces of Lima including the capital Lima Metropolitana and recovered 341 E. coli isolates. We found that 21.3% (42/197) and 12.5% (18/144) of the chicken and pig strains were mcr-1-positive by PCR, respectively. The whole genome sequencing of 14 mcr-1-positive isolates revealed diverse sequence types (e.g., ST48 and ST602) and the presence of other 38 genes that confer resistance to 10 different classes of antibiotics, including beta-lactamase blaCTX-M-55. The mcr-1 gene was located on diverse plasmids belonging to the IncI2 and IncHI1A:IncHI1B replicon types. A comparative analysis of the plasmids showed that they contained the mcr-1 gene within varied structures (mikB-mcr1-pap2, ISApl1-mcr1-pap2, and Tn6330). To the best of our knowledge, this is the first attempt to study the prevalence of the mcr-1 gene in livestock in Peru, revealing its high occurrence in pig and chicken farms. The genetic diversity of mcr-1-positive strains suggests a complex local epidemiology calling for a coordinated surveillance under the One-Health approach that includes animals, retail meat, farmers, hospitals and the environment to effectively detect and limit the spread of colistin-resistant bacteria.

Drug-Resistant Proteus Virulence Factors Characterization and Their Inhibition Using Probiotic Bacteria

Background: The genus Proteus is a Gram-negative bacterium with a unique characteristic of swarming. Mainly three species are involved in initiating urinary tract infections in the community and in immunocompromised patients, particularly in patients going through long-term catheterization. Due to their strong virulence factors like biofilm formations, protease, and hemolysin, they can lead to lengthening infections in affected individuals. Probiotics are live bacteria and yeasts that are beneficial to human health and can be used as an alternative for the control of nosocomial diseases. Lactobacilli are one of the common probiotics mostly found in yogurt and other fermented foods that have been used as a substitute for infection control. Objectives: The current study was designed to screen potential probiotic bacteria to encounter antibiotic-resistant and virulent Proteus species. Methods: In the current study, using probiotics, already known antibiotic-resistant isolates (n = 25) of Proteus were processed to characterize their virulence factors and their inhibition. Biofilm formation, protease, and hemolysin activities were studied using different phenotypic detection methods. Further, their virulence genes zapA, flg, hmpA, mrp, and rsbA were explored using their genomic DNA. These isolates were found resistant to different classes of antibiotics, and a strategy was designed to inhibit their growth by using probiotic bacteria isolated from the soil. Results: Virulence factors first, all isolates were subjected to biofilm detection, and they were 32% (n = 8) strong, 40% (n = 10) moderate, 16% (n = 4) weak, and 12% (n = 3) non-biofilm producers. All isolates were positive for swarming activity by showing a differentiated ring form of growth. Protease activity showed 56% (n = 14) isolates. Only 24% (n = 6) of isolates were positive for hemolysin. Virulence factors and molecular mechanisms were studied, and gene rsbA responsible for swarming was amplified in 17 (68%) Proteus isolates, and mrp responsible for fimbria was detected in 19 (76%) bacterial isolates. Further, these isolates were subjected to flagella, protease, and hemolysin, and it was revealed that flg 11 (44%), 13 (52%) protease coding zapA, and hmA gene coding hemolysin were amplified in 2 (8%) Proteus isolates. Probiotic bacteria isolated from soil samples were probed for antagonistic activity against Proteus species. The probiotic bacteria were identified as Lactobacillus plantarum, Bacillus subtilis, and B. licheniformis. Due to their strong growth inhibitory effects against Proteus, it is crucial to characterize further the metabolites that have shown suppressive results against Proteus. Conclusions: Findings from the current study will provide new avenues for drug development and also help clinicians manage resistant pathogens in healthcare settings. Probiotic applications for infection control can be useful in treating resistant pathogens. Further purification and characterization of metabolites will provide alternative options for managing resistance issues in microbes.

Alarming Antibiotic Resistance of Lactobacilli Isolated from Probiotic Preparations and Dietary Supplements.

In this study, we screened eight commercially available brands of Lactobacillus-containing probiotic preparations and dietary supplements for resistance towards commonly administered antibiotics of different classes. According to disc diffusion results, most of the isolates were resistant to vancomycin and susceptible to penicillin-type antibiotics (ampicillin and amoxicillin), carbapenems (imipenem, meropenem, and ertapenem), and inhibitors of protein synthesis (chloramphenicol, erythromycin, tetracycline, clarithromycin, and linezolid). However, based on minimum inhibitory concentration (MIC) values, six strains were reconsidered as resistant to tetracycline. All tested lactobacilli were resistant towards amikacin, ciprofloxacin, and norfloxacin. Resistance to cephalosporins was highly variable and decreased in the following order: ceftazidime/cefepime, ceftriaxone, cefotaxime, cefazolin, and cefoperazone. PCR screening for antibiotic resistance determinants in probiotic lactobacilli revealed a wide occurrence of vancomycin resistance gene vanX, ciprofloxacin resistance gene parC, and extended-spectrum β-lactamase gene blaTEM. We also detected the tetK gene for tetracycline resistance in one isolate. Additionally, we identified discrepancies between the claims of the manufacturers and the identified species composition, as well as the enumerated amount of viable bacteria, for several products. The results of this study raise concerns about the safety of lactobacilli for human consumption as probiotics, as they may act as reservoirs of transferable antibiotic resistance genes.

The significant role of Carbapenems-resistant Acinetobacter Baumannii in mortality rate of patients with COVID-19

Background: Infections caused by Acinetobacter baumannii, especially carbapenem-resistant (CR) strains, pose important challenges in patients with COVID-19 infection. Therefore, in the present study, we investigated co-infection and antimicrobial resistance patterns, as well as the role of A. baumannii in the outcome of patients with COVID-19.Materials and methods: Between February 2019 and January 2021, 141 patients with A. baumannii infections were detected from seven different hospitals (A to G) in Arak, Iran, and the antibacterial susceptibility pattern of these isolates was evaluated using disk diffusion and E-test methods. Forty-seven of these patients were co-infected with COVID-19. During the study, the data about the clinical course, demographic data, and the role of A. baumannii infections in the mortality rate of COVID-19 patients were collected.Results: Hospitals A and B reported the most patients, with 53 (38%) and 47 (33%), respectively. Additionally, most cases (105 cases, 75%) were reported from surgical and general ICUs. Mechanical ventilators were detected as predisposing factors in 95 (67%) patients, and infection was detected in 20% of patients on the 10th day after intubation. All of the A. baumannii isolates were resistant to different classes of antibiotics, such as carbapenems. Notably, 33% (47 patients) were also positive for COVID-19, and 68% (32 patients) died due to the infection. Statistical analysis showed a significant role of A. baumannii co-infection in the mortality rate of COVID-19 patients (p-value 0.05).Conclusion: co-infection with A. baumannii is one of the most important challenges in COVID-19 patients. Our results showed that all isolated bacteria were CR and significantly increased mortality rates in COVID-19 patients.

Hospital-Based Air-Borne and Surface-Borne Bacterial Pathogens and Their Antimicrobial Profiles in Wolaita Sodo, Southern Ethiopia.

It is well documented that hospital environments are the niche/reservoir of many clinically important microorganisms, including multidrug-resistant air-borne and surface-borne pathogens. This problem is the most pressing public health concern, particularly in developing countries like Ethiopia, due to its poor infection management system. This study was planned to detect air-borne and surface-borne bacterial pathogens and their antimicrobial resistance patterns in Wolaita Sodo University Comprehensive Hospital, Southern Ethiopia. A laboratory-based cross-sectional study was conducted from May to July 2021. Swabbing and open-plate sample collection methods were used to collect specimens. Standard bacteriological techniques were used to isolate and identify bacterial pathogens. The Mueller-Hinton agar was used to detect the drug susceptibility pattern of bacteria by using the Kirby-Bauer disc diffusion method. From a total of 323 samples tested, 118 (36.5%) showed the growth of bacteria. The detection rate of bacterial pathogens in the intensive care unit (35.4%) was higher than in operation theater. From the total of 118 bacterial isolates, 39.8%, 27.9%, 20.3%, and 11.5% of S. aureus, P. aeruginosa, Klebsiella pneumoniae, and E. coli, respectively, were surface-borne. Whereas 37%, 25%, 20.83, and 16.6% of S. aureus, P. aeruginosa, Klebsiella species, and E. coli, respectively, were air-borne. S. aureus showed a 19.04 to 80.9% range of antimicrobial resistance to different classes of antibiotics from surface specimens. A 12.5-100% range of antibiotic resistance levels was detected for all Gram-negative surface-borne bacterial pathogens. P. aeruginosa was 66.7%, 73.3%, and 73.3% resistant to gentamicin, chloramphenicol, and ceftriaxone, respectively. K. pneumoniae showed 75% and 87.5% resistance to ceftriaxone and ciprofloxacin, respectively, and a completely ampicillin-resistant E. coli was detected. From a total of 48 bacterial pathogens identified from surfaces in the intensive care unit, 34 (70.8%) developed multidrug resistance. A significant prevalence of surface-borne bacterial pathogens was detected. This study revealed that S. aureus, P. aeruginosa, K. pneumoniae, and E. coli were nosocomial infection concerns of the hospital, and this could be the reason for different types of hospital acquired infections in the study area. A high prevalence of MDR was detected in the most surface-borne bacterial isolates.

Antibiotic resistance profiles and activity of clove essential oil (Syzygium aromaticum) against Pseudomonas aeruginosa isolated of canine otitis.

Pseudomonas aeruginosa is often isolated from acute and chronic otitis and deep pyoderma in dogs. The increase in bacterial resistance to antibiotics induced the need for alternative therapies to treat infections, with an emphasis on essential oils (EOs). This study aimed to investigate clove oil's in vitro bactericidal action as a therapeutic alternative against strains of P. aeruginosa isolated from canine otitis. The antibacterial activity of clove oil was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the broth microdilution technique in 96-well plates. Serial concentrations of 10-0.31% of the oil were used, equivalent to 104.5-3.26 mg/mL. The susceptibility of isolates to different classes of antibiotics was determined by the disk diffusion technique using 20 antibiotics belonging to eight classes. Isolates resistant to at least one antibiotic of three different classes were considered multidrug-resistant (MDR). A high occurrence of resistance was observed for three antibiotics belonging to the cephalosporin classes (cefadroxil, cephalexin, and ceftriaxone), namely, sulfamethoxazole + trimethoprime, doxycycline, and enrofloxacin. The lowest resistance rates were observed for meropenem (4.88%), amikacin (12.20%), and tobramycin (12.2%). All isolates were susceptible to clove oil with an equivalent MIC and MBC from 3.26 to 6.53 mg/mL. Eugenol was the major component of the oil. Clove EO was effective against MDR strains of P. aeruginosa, indicating an alternative for developing an efficient and low-cost antimicrobial agent to treat canine otitis.

Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in a Tertiary Hospital from the Comunidad Valenciana (Spain).

To reduce the high rates of morbidity and mortality caused by methicillin-resistant Staphylococcus aureus (MRSA) strains, it is essential to prevent their transmission. This can be achieved through molecular surveillance of the infecting strains, for which the detection of the entry of new strains, the analysis of antimicrobial resistance, and their containment are essential. In this study, we have analyzed 190 MRSA isolates obtained at the Consorcio Hospital General Universitario de Valencia (Spain) from 2013 to 2018 with three approaches: Multilocus Sequence Typing, spa, and SCCmec typing. Although the incidence of S. aureus infections detected in the hospital increased in the study period, the frequency of MRSA isolates decreased from 33% to 18%. One hundred seventy-two MRSA isolates were resistant to three or more classes of antimicrobials, especially to fluoroquinolones. No relevant temporal trend in the distribution of antibiotic susceptibility was observed. The combination of the three typing schemes allowed the identification of 74 different clones, of which the combination ST125-t067-IV was the most abundant in the study (27 cases). Members of three clonal complexes, CC5, CC8, and CC22, comprised 91% of the isolates, and included 32 STs and 32 spa types. The emergence of low incidence strains throughout the study period and a large number of isolates resistant to different classes of antibiotics shows the need for epidemiological surveillance of this pathogen. Our study demonstrates that epidemiological and molecular surveillance is a powerful tool to detect the emergence of clinically important MRSA clones.

Effect of antibiotics and sanitizers on Salmonella biofilms associated with seafood contact surfaces

This study investigates the effect of antibiotics and sanitizers on biofilm forming Salmonella isolated from different seafood contact surfaces. Four Salmonella were isolated from 384 swab samples collected from various contact surfaces of fishing boats, fish landing centres and seafood processing plants. One out of four isolates was from the fishing boat (FB I -1) other three isolates were from the seafood processing plant (FPPII -4, FPPII- 5, FPPI-3). The ability of Salmonella to form biofilms on different contact surfaces (HDPE, stainless steel, wood, glass, tiles) was tested with the microbial load on different incubation days, and a higher count was observed on day five. The effect of sanitizer viz., sodium hypochlorite (20, 50, 100, 200 mg/l) and iodophor (2, 5, 10 mg/l) on the biofilm formed on different seafood contact surfaces were investigated. A reduction of 2–3 log was observed on surfaces of HDPE and stainless steel when they were treated with a minimum of 5 mg/l of iodophor or 20 mg/l of sodium hypochlorite after a contact time of 5 min. Antibiotic resistance of biofilm forming Salmonella was tested for different classes of antibiotics (penicillin, ß-lactams, quinolones, macrolides, aminoglycosides, phenol drugs, sulfonamides, cephalosporin). All four isolates showed intermediate resistance to ciprofloxacin, a quinolone drug. Only one isolate FB I -1 (fishing boat deck) expressed resistance to more drugs, viz., ßlactams (AMC, AMP, penicillin G), macrolides (AZM) and nitrofurantoin (NIT). These findings shall help the seafood processors to mitigate the formation of Salmonella biofilms on various seafood contact surfaces with different sanitizers and the antibiotic resistance of biofilm forming Salmonella shall give knowledge on human clinical treatments. With this study, we shall recommend the regulatory authorities control the contamination level of fish handling areas.

Structure and function response of bacterial communities towards antibiotic contamination in hyporheic zone sediments

Bacterial communities are crucial for processing and degrading contaminants in hyporheic zones (HZ). However, the effects of antibiotics on HZ bacterial communities have seldom been addressed. Here, using MiSeq 16S amplicon sequencing technology, the effects of acute exposure to Enrofloxacin, Sulfathiazole, Tetracycline hydrochloride, and Penicillin V potassium on HZ bacterial communities were investigated. Results revealed that HZ sediment communities responded differently to different classes of antibiotics, reflecting the distinct selection stress of antibiotics on HZ bacterial communities. Besides, HZ communities from the locations with more severe antibiotic contamination backgrounds (∼150 μg kg−1) were more resistant towards antibiotic treatment. Compared with small/non-significant changes in HZ community diversity and composition treated with ng L−1∼ug L−1 level antibiotics compared to the control group, treatments with antibiotics over mg L−1 level significantly reduced the diversity and changed the structures of HZ bacterial communities, and enhanced the resistance of the community to antibiotics by enriching antibiotic resistant bacteria. The exposure to mg L−1 level antibiotics also changed community functions by restricting the growth of functional bacteria, such as ammonia oxidizing bacteria (AOB) Nitrosomonas, resulting in ammonia accumulation in sediments. The results implied that at field-relevant concentrations, there was no or minor effect of antibiotics on HZ bacterial community structure and functions, and only those areas with high antibiotic concentrations would have effects.