Bacterial Isolates Research Articles

An Etiology of Sputum Culture Contamination and their Drugs Susceptibility Patterns among TB-suspected Patients at Epicentre Mbarara Research Centre, Uganda

Aims: Contamination in TB cultures is problematic as it allows the growth of non-target bacterial or fungal species in sputum samples, potentially concealing M. tuberculosis. This study aimed to determine the prevalence, characterization, and drug susceptibility patterns of contaminants in sputum cultures from TB-suspected patients. Methods: A laboratory-based cross-sectional study was conducted from October 2023 to June 2024 at the Epicentre Mbarara Research Centre, involving 81 sputum samples from TB-suspected patients. Conventional decontamination procedures were used, and both solid Lowenstein Jensen (LJ) and liquid Mycobacterium Growth Indicator Tube (MGIT) culture methods were applied. Standard culture techniques and physicochemical analyses were employed. Bacteria were incubated at 37°C in O2 and Co2 incubators, with growth observed within 24 to 48 hours and up to three days for yeast contaminants. Sabouraud Dextrose Agar cultures were monitored for two weeks for filamentous fungi. Antibiograms for bacterial isolates were determined using the Kirby-Bauer, while broth microdilution was used for fungal isolates. Results: Of 81 samples, 14(17.28%) were contaminated. The most common bacterial contaminants were Staphylococcus aureus, Bacillus subtilis, Streptococcus viridans, Staphylococcus epidermidis, and Escherichia coli. Fungal contaminants included Aspergillus flavus, Penicillium species, Candida albicans, Cryptococcus neoformans, and non-albican Candida species. High resistance to erythromycin (73%) and tetracycline (50%) was noted among bacterial isolates, with sensitivity to vancomycin (67%), gentamycin (60%), and chloramphenicol (58%). Yeast isolates showed (87.5%) susceptibility to itraconazole and (75%) to amphotericin B but (50%) resistance to 5-flucytosine. Mold isolates exhibited (100%) susceptibility to itraconazole, amphotericin B, and 5-flucytosine but complete resistance to caspofungin. Conclusion: The level of contamination in TB cultures was noted, and Staphylococcus aureus and Candida albicans were observed as the most common contaminants. Bacterial isolates resisted erythromycin and tetracycline, while fungal isolates were generally susceptible to itraconazole and amphotericin B. We recommend Strengthening decontamination and monitoring common resistant contaminants.

Isolation and characterization of non-rhizobial bacteria and arbuscular mycorrhizal fungi from legumes.

This study investigates non-rhizobial endophytic bacteria in the root nodules of chickpea (Cicer arietinum L), faba bean (Vicia faba), and cowpea (Vigna unguiculata L. Walp), as well as arbuscular mycorrhizal fungi in the rhizospheric soil of chickpea and faba bean. Out of the 34 endophytic bacterial populations examined, 31 strains were identified as non-rhizobial based on nodulation tests. All strains were assessed for their plant growth-promoting (PGP) activities in vitro. The results revealed that most isolates exhibited multiple PGP activities, such as nitrogen fixation, indole-3-acetic acid (IAA) and ammonia (NH3) production, phosphate solubilization, and exopolysaccharide production. The most effective PGP bacteria were selected for 16S rRNA analysis. Additionally, a total of 36 species of native arbuscular mycorrhizal fungi (AMF) were identified. Acaulospora (100%) and Scutellospora (91.66%) were the most prevalent genera in Cicer arietinum L. and Vicia faba L. plants, respectively. Acaulospora also exhibited the highest spore density and relative abundance in both plants. Moreover, the root colonization of Cicer arietinum L. and Vicia faba L. plants by hyphae, vesicles, and arbuscules (HVA) was significant. The findings of this study provide valuable insights into non-rhizobial endophytic bacteria associated with legume root nodules and the diversity of AMF. These organisms have great potential for PGP and can be manipulated by co-inoculation with rhizobia to enhance their biofertilizer effectiveness. This manipulation is crucial for promoting sustainable agriculture, improving crop growth, and advancing biofertilizer technology.

Evaluation of a microfluidic-based point-of-care prototype with customized chip for detection of bacterial clusters.

Especially in medical facilities, where morbid people are nursed in close distance to each other, pathogenic bacteria can accumulate and spread. To contain such infection clusters, usually time- and labor-intensive large-scale screening assays are conducted, where patients and patient-side surfaces are sampled, and PCR or whole-genome sequencing analyses are conducted to confirm or deny cluster affiliation of cultivated bacteria. Hence, fast solutions with easy application are required to complement the current state-of-the-art technology for cluster surveillance. Here, we developed a fully automated microfluidic point-of-care prototype that identified bacterial cluster isolates within 70 min from bacterial solutions, including swab eluates. The system requires only low hands-on time and can be applied apart from laboratory infrastructures near the patient, which considerably reduces the time from sampling to result. This ensures fast implementation of hygiene measures and quick containment of the infection cluster, which would enhance patients' safety and outcome.

Primary screening of growth-stimulating properties of rhizosphere microorganisms in relation to tomato seeds

The ability of bacterial isolates isolated from the rhizosphere of cultivated and wild plants of arid ecosystems of the Astrakhan region, which have the ability to tryptophan-induced synthesis of indolyl-3-acetic acid, to stimulate the germination of tomato seeds of the varieties “Sanka”, “Volgogradsky”, “Cosmonaut Volkov”, was studied. “Newbie” Experimental studies were carried out through laboratory experiments by incubating seeds in humid chambers; laboratory germination and morphometric parameters of seedlings were assessed. It was revealed that most of the studied suspensions of isolates have a stimulating effect on tomato seeds. High germination (90% or more) of seeds of the “Sanka” variety was observed when 12 isolates were treated with suspensions; variety “Volgogradsky” – suspensions of 9 isolates; variety “Cosmonaut Volkov” – suspensions of 2 isolates; variety “Novichok” – suspensions of 3 isolates. Suspensions of isolates 16/19 and 31/20 contributed to high germination of seeds of all varieties: up to 86.6–100% and 90–100%, respectively, and isolate 9/19 significantly reduced the germination of seeds of the varieties “Volgogradsky”, “Cosmonaut Volkov” and “Novichok” by 66.6–56.7%. When assessing the morphometric parameters of seedlings in the experiment, it was noted that the suspension of isolate 16/19 helps to increase the biomass of the varieties “Sanka”, “Volgogradsky” and “Cosmonaut Volkov” up to 273–449%. Suspension of isolate 31/20 has a stimulating effect on the morphometric parameters of seedlings of all varieties: it stimulates root development by 73.3–183.3%, stem development by 46.8–100.5%. The isolate 9/19 suspension not only inhibits seed germination, but also causes a reduced accumulation of seedling biomass, inhibits the development of roots and stems of seedlings of the varieties “Volgogradsky”, “Cosmonaut Volkov” and “Novichok”. Thus, during experimental studies, isolates (16/19 and 31/20) of rhizosphere bacteria were identified that have a stimulating effect on both the germination of tomato seeds and the morphometric parameters of seedlings.

Fosfomycin—Overcoming Problematic In Vitro Susceptibility Testing and Tricky Result Interpretation: Comparison of Three Fosfomycin Susceptibility Testing Methods

Background: Fosfomycin (FOS) is an older antimicrobial agent newly rediscovered as a possible treatment for infections with limited therapeutic options (e.g., Gram-negative bacteria with difficult-to-treat resistance, DTR), especially in intravenous form. However, for correct usage of FOS, it is necessary to have a reliable susceptibility testing method suitable for routine practice and robust interpretation criteria. Results: The results were interpreted according to 2023 interpretation criteria provided by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). DTR Gram-negatives were more likely to be resistant to FOS (45% in Enterobacterales and 20% in P. aeruginosa) than non-DTR (10% and 6.7%, resp.). All isolates of S. aureus were susceptible to FOS. In Gram-negatives, all agreement values were unacceptable. Etest® performed better in the DTR cohort (categorical agreement, CA, 80%) than in the non-DTR cohort (CA 45.7%). There were no very major errors (VREs) observed in P. aeruginosa. S. aureus had surprisingly low essential agreement (EA) rates (53% for MRSA and 47% for MSSA) for Etest®, but categorical agreement was 100%. Methods: A total of 130 bacterial isolates were tested and compared using the disc diffusion method (DD) and gradient strip method (Etest®) with the reference method (agar dilution, AD). The spectrum of isolates tested was as follows: 40 Enterobacterales (20 DTR vs. 20 non-DTR), 30 Pseudomonas aeruginosa (15 DTR vs. 15 non-DTR), and 60 Staphylococcus aureus (30 methicillin-susceptible, MSSA, vs. 30 methicillin-resistant, MRSA). Conclusions: Neither one of the tested methods was identified as a suitable alternative to AD. It would be beneficial to define more interpretation criteria, at least in some instances.

Comprehensive evaluation of the antibacterial and antibiofilm activities of NiTi orthodontic wires coated with silver nanoparticles and nanocomposites: an in vitro study.

Fixed orthodontic appliances act as a niche for microbial growth and colonization. Coating orthodontic wires with antimicrobial silver nanoparticles (AgNPs) and nanocomposite was adopted in this study to augment the biological activity of these wires by increasing their antibacterial and antibiofilm properties and inhibiting bacterial infections that cause white spot lesions and lead to periodontal disease. Three concentrations of biologically synthesized AgNPs were used for coating NiTi wires. The shape, size, and charge of the AgNPs were determined. Six groups of 0.016 × 0.022-inch NiTi orthodontic wires, each with six wires, were used; and coated with AgNPs and nanocomposites. The antimicrobial and antibiofilm activities of these coated wires were tested against normal flora and multidrug-resistant bacteria (Gram-positive and Gram-negative bacterial isolates). The surface topography, roughness, elemental percentile, and ion release were characterized. AgNPs and nanocomposite coated NiTi wires showed significant antimicrobial and antibiofilm activities. The chitosan-silver nanocomposite (CS-Ag) coated wires had the greatest bacterial growth inhibition against both Gram-positive and Gram-negative bacteria. The surface roughness of the coated wires was significantly reduced, impacting the surface topography and with recorded low Ni and Ag ion release rates. NiTi orthodontic wires coated with AgNPs, and nanocomposites have shown increased antimicrobial and antibiofilm activities, with decreased surface roughness, friction resistance and limited- metal ion release.

Caracterización fenotípica y simbiótica de las bacterias que nodulan Genista saharae en la región árida de Argelia

Twenty bacterial strains had been isolated from root nodules of Genista saharae that grew wild in Biskra and El Oued city (Northeastern Algerian Sahara). This study focused on obtaining isolates of legume nodule bacteria (LNB) from the plant G. saharae and evaluated their effectiveness in forming a symbiotic relationship with the legume species Vigna unguiculata through cross-inoculation. Additionally, the study aimed to identify the successful cross-inoculation group of LNB strains based on their phenotypic characteristics. The growth capacity of isolates under varying salinity conditions [NaCl] and pH levels was investigated using a spectrophotometer (96-microplate reader). The API 20NE and API 20E systems were used to identify the biochemical characteristics of the isolates. In addition, the rhizospheric soil samples from the two study sites were analyzed using standard analytical techniques of soil. All isolates established effective symbioses with Vigna unguiculata, were Gram-negative rods, and were fast-growing. The optimal growth temperature was between 28 °C and 37 °C; some isolates were thermophiles and specifically withstood extreme heat between 45-50 °C. Furthermore, they demonstrated a wide tolerance range to pH (5–10) with salt tolerance ranging from 100 mM to 500 mM. Biochemical results revealed that the isolates assimilated various sources of carbon and nitrogen and displayed numerous enzyme activities. Physicochemical analysis revealed that all the soils were deficient in nutrients and had an alkaline pH. This study enabled us to identify the effective stress-tolerant strains, which could be used in the future to inoculate plants for environmental applications. Keywords: Rhizobia, morpho-physiological and biochemical characterization.

Culture-Dependent Characterization of Hydrocarbon Utilizing Bacteria and Fungi from an Artisanal Crude Oil Refining Site

Crude oil refining is a global insert responsible for the production of a wide array of petroleum based products crucial for various sectors including energy, transportation, and manufacturing. However, the artisanal form of crude oil refining, often characterized by its small scale and limited technological infrastructure, has emerged as a major environmental concern in several regions around the world. Illegal refining of crude oil has led to oil spillages which in turn lead to a disruption of the microbial population of the soil. Hence, the aim of this study was to isolate and characterize the heterotrophic and hydrocarbon utilizing bacteria and fungi from an artisanal crude oil refining site. A total of thirty six (36) soil samples were collected from three (3) artisanal crude oil refining sites at iwofe, ogbogoro and ibaa community all in Rivers State, Nigeria. The samples were collected using soil auger and subjected to standard microbiological procedures such as culturing, isolation and identification. The results revealed significantly elevated levels of heterotrophic and hydrocarbon utilizing bacteria and fungi in the soil samples, with notable variations (p≤0.05) across the different artisanal crude oil refining sites. Total Heterotrophic Bacteria (THB) counts ranged from 3.75x105CFU/g in Iwofe to 2.70x105CFU/g in Ibaa, Total heterotrophic Fungal (THF) counts ranged from 2.80x104CFU/g recorded in Ogbogoro to 1.45x104CFU/g recorded in Iwofe, Hydrocarbon Utilizing Bacteria (HUB) counts ranged from 2.25x103CFU/g in Ibaa to 1.30x103CFU/g in Iwofe and Hydrocarbon Utilizing Fungi (HUF) counts ranged from 2.50x102CFU/g recorded in Ogbogoro to 1.40x102CFU/g recorded in Ibaa community with significant differences (p≤0.05). Bacteria isolated and characterized from the soil include Enterobacter, Pseudomonas putida, Serratia and Bacillus amyloliquefaciens while fungi include Fusarium, Aspergillus, Penicillium and Mucor. The microorganisms identified in this study have been reported to play key roles in the utilization of crude oil. Pseudomonas and Bacillus were the most dominant bacterial isolates and their dominance could imply that the soil could support the growth of crops. Thus, while they utilize the hydrocarbons, they also serve as plant-growth promoting microorganisms. Although some of the microorganisms in the present study have been reported to promote the growth of plant, the dumping of crude oil products legal or illegal should be minimized to avoid the extinction of plant-promoting microorganisms.

Personalized CZA-ATM dosing against an XDR E. coli in liver transplant patients; the application of the in vitro hollow fiber system.

A patient with an extensively drug-resistant (XDR) New Delhi metallo-β-lactamase (NDM) and oxacillinase (OXA-48) producing Escherichia coli (E. coli) infection was awaiting orthotopic liver transplant. There is no standardized antibiotic prophylaxis regimen; however, in line with the Infectious Diseases Society of America guidance, an antibiotic prophylactic regimen of ceftazidime-avibactam 2.5g TDS with aztreonam 2g three times a day (TDS) IV was proposed. The hollow fiber system (HFS) was applied to inform the individualized pharmacodynamic outcome likelihood prior to prophylaxis. A 4-log reduction in CFU/mL in the first 10 h of the regimen exposure was observed; however, the killing dynamics were slow and six 8-hourly infusions were required to reduce bacterial cells to below the limit of quantification. Thus, the HFS supported the use of the regimen for infection clearance; however, it highlighted the need for several infusions. Standard local practice is to administer prophylaxis antibiotics at induction of orthotopic liver transplantation (OLT); however, the HFS provided data to rationalize earlier dosing. Therefore, the patient was dosed at 24 h prior to their OLT induction and subsequently discharged 8 days after surgery. The HFS provides a dynamic culture solution for informing individualized medicine by testing antibiotic combinations and exposures against the bacterial isolates cultured from the patient's infection. .

Bacterial isolates and antibiotic sensitivity in canine bacterial keratitis in Korea.

To analyze bacterial isolates associated with canine bacterial keratitis and their antibiotic susceptibility patterns in Korea, focusing on multidrug resistance (MDR) and identifying effective antibiotic combinations for clinical treatment. A total of 146 dogs diagnosed with suspected bacterial keratitis between October 2022 and October 2023 in Korea, with 157 eye samples collected for analysis. Eye samples were cultured to isolate bacteria, and antibiotic susceptibility testing was performed using the minimum inhibitory concentration (MIC) method. Bacterial identification was conducted using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF). The study assessed the efficacy of individual antibiotics and combination therapies. Bacteria were isolated in 55.4% of the samples. The most common genera were Staphylococcus species (48.5%, 48/99), Streptococcus species (13.1%, 13/99), Pseudomonas species (9.1%, 9/99), and Escherichia coli (9.1%, 9/99). Amikacin (84.8%) showed the highest antibiotic susceptibility, while doxycycline exhibited the lowest (17.2%). The most effective antibiotic combinations were amikacin-moxifloxacin (93%). MDR isolates accounted for 52.5% (52/99) of the total bacterial samples. Staphylococcus species were the most common isolates, with 52.5% showing MDR, underscoring the need to curb antibiotic misuse. While antibiotics like amikacin demonstrated high susceptibility rates, their use should be reserved for resistant infections to prevent further resistance development. Rather than focusing solely on finding effective combinations of antibiotics, it is crucial to consider alternative treatment strategies that offer more sustainable solutions. Rather than relying on antibiotic combinations, attention should shift to sustainable alternatives to treat bacterial keratitis and reduce antibiotic dependence in clinical practice.

Deciphering Phyllomicrobiome of Cauliflower Leaf: Revelation by Metagenomic and Microbiological Analysis of Tolerant and Susceptible Genotypes Against Black Rot Disease.

Understanding the phyllomicrobiome dynamics in cauliflower plants holds significant promise for enhancing crop resilience against black rot disease, caused by Xanthomonas campestris pv. campestris. In this study, the culturable microbiome and metagenomic profile of tolerant (BR-161) and susceptible (Pusa Sharad) cauliflower genotypes were investigated to elucidate microbial interactions associated with disease tolerance. Isolation of phyllospheric bacteria from asymptomatic and black rot disease symptomatic leaves of tolerant and susceptible cultivars yielded 46 diverse bacterial isolates. Molecular identification via 16S rRNA sequencing revealed differences in the diversity of microbial taxa between genotypes and health conditions. Metagenomic profiling using next-generation sequencing elucidated distinct microbial communities, with higher diversity observed in black rot disease symptomatic leaf of BR-161. Alpha and beta diversity indices highlighted differences in microbial community structure and composition between genotypes and health conditions. Taxonomic analysis revealed a core microbiome consisting of genera such as Xanthomonas, Psychrobacillus, Lactobacillus, and Pseudomonas across all the samples. Validation through microbiological methods confirmed the presence of these key genera. The findings provide novel insights into the phyllomicrobiome of black rot-tolerant and susceptible genotypes of cauliflower. Harnessing beneficial microbial communities identified in this study offers promising avenues for developing sustainable strategies to manage black rot disease and enhance cauliflower crop health and productivity.

Prospects of iron solubilizing Bacillus species for improving growth and iron in maize (Zea mays L.) under axenic conditions

Iron (Fe) deficiency in calcareous soils is a significant agricultural challenge, affecting crop productivity and nutritional quality. This study aimed to isolate, characterize, and evaluate Fe solubilizing rhizobacterial isolates from maize rhizosphere in calcareous soils as potential biofertilizers. Forty bacterial isolates coded as SG1, SG2, …, SG40 were isolated and screened for siderophore production, with ten showing significant Fe solubilizing capabilities. These isolates were further assessed for phosphate solubilization and exopolysaccharides production. The selected bacterial isolates were also screened under axenic conditions for their ability to improve maize growth. The isolates SG8, SG13, SG24, SG30 and SG33 significantly enhanced growth parameters of maize. Notably, SG30 showed highest increment in shoot length (58%), root length (54%), root fresh and dry biomass (67% and 76%), SPAD value (67%), relative water contents (69%), root surface area (61%), and Fe concentration in shoots (79%) as compared to control. The biochemical characterization of these strains showed that all these strains have capability to solubilize insoluble phosphorus, produce indole-3-acetic acid (IAA), and ammonia with catalase, urease and protease activity. Molecular identification through 16s rRNA gene sequencing confirmed high similarity (99.7–100%) of the selected isolates to various Bacillus species, including B. pyramidoids, B. firmicutes, and B. cereus. The study provides a strong base for developing eco-friendly, cost-effective biofertilizers to address Fe deficiency in crops and promote sustainable agriculture.

Molecular Identification, Histopathology and Antibiotic Susceptibility Profiling of Aeromonas veronii Isolated from Oreochromis niloticus in Bangladesh.

Tilapia (Oreochromis niloticus) is the most widely cultured freshwater fish species in Bangladesh and worldwide. However, commercial tilapia culture systems face increasing challenges from bacterial infections. The objective of this study was to identify the bacterial isolates from infected tilapia inan intensive cage culture farm located along the Shitalakshya River in Bangladesh. Infected fish samples were collected and underwentcomprehensive clinical and post-mortem investigations, followed by phenotypic, biochemical and molecular identification of the bacterial isolates, as well as histopathological and antibiotic susceptibility examinations. Phenotypic and biochemical characterization showed similarities of the -collected isolates with Aeromonas veronii. Moreover, molecular analysis of the bacterial conserved region 16S rRNA also confirmed these isolates as A. veronii. The analysed 16S rRNA sequence (GenBank accession no. PP832815) showed a close relationship (100% identity) with A. veronii from China (GenBank accession no. MT071624) in the NCBI BLAST search, and in the phylogenetic tree, they grouped in a single clade. This close genetic relationship is also supported by the low genetic distance between the isolates. Histopathological analysis revealed gross pathological changes like necrosis, hypertrophy and inflammation in muscle tissues. The isolates were found to be sensitive to multiple antibiotics but resistant to trimethoprim and sulphamethoxazole. This study investigated the presence of A. veronii infection in tilapia (O. niloticus) in an intensive cage culture farm in Bangladesh.

Isolation and identification of lactic acid bacteria from artisanal Turkish cheeses, and evaluation of γ-aminobutyric acid (GABA) production potential

Isolation and identification of lactic acid bacteria from artisanal Turkish cheeses, and evaluation of γ-aminobutyric acid (GABA) production potential

Biofilm formation and antibiogram profile of bacteria from infected wounds in a general hospital in southern Ethiopia

Biofilm-producing bacteria associated with wound infections exhibit exceptional drug resistance, leading to an escalation in morbidity, worse clinical outcomes (including delay in the healing process), and an increase in health care cost, burdening the whole system. This study is an attempt to estimate the prevalence and the relationship between the biofilm-forming capacity and multi-drug resistance of wound bacterial isolates. The findings intended to help clinicians, healthcare providers and program planners and to formulate an evidence-based decision-making process, especially in resource-limited healthcare settings. This study was done to assess the prevalence of bacterial infections in wounds and the antibiogram and biofilm-forming capacity of those bacteria in patients with clinical signs and symptoms, attending a General Hospital in southern Ethiopia. A cross-sectional study was performed in Arba Minch General Hospital from June to November 2021. The study participants comprised 201 patients with clinically infected wounds. Demographic and clinical data were gathered via a structured questionnaire. Specimens from wounds were taken from each participant and inoculated onto a series of culture media, namely MacConkey agar, mannitol salt agar, and blood agar, and different species were identified using a number of biochemical tests. Antimicrobial susceptibility tests were performed by means of the Kirby-Bauer disc diffusion technique following the guidelines of the Clinical and Laboratory Standards Institute. A micro-titer plate method was employed to detect the extent of biofilm formation. Bivariable and multivariable logistic regression models were applied to analyse the association between dependent and independent variables, and P values ≤ 0.05 were considered as statistically significant. Data analyses were done with Statistical Package for the Social Sciences version 25. Out of the 201 clinically infected wounds, 165 were found culture-positive with an overall prevalence of 82% (95% CI: 75.9–86.9). In total, 188 bacteria were recovered; 53.1% of them were Gram-positive cocci. The often-isolated bacterial species were Staphylococcus aureus, 38.3% (n = 72), and Pseudomonas aeruginosa, 16.4% (n = 31). The Gram-positive isolates showed considerable resistance against penicillin, 70%, and somewhat strong resistance against tetracycline, 57.7%. Gram-negative isolates showed severe resistance to ampicillin, 80.68%. The overall multi-drug resistance (MDR) among isolates was 48.4%. Extended beta-lactamase (ESBL)-producing Gram-negatives and methicillin-resistant Staphylococcus aureus (MRSA) accounted for 49 and 41.67%, respectively; 62.2% of the isolates were biofilm formers and were correlated statistically with MDR, ESBL producers, and MRSA (P < 0.005). The extent of biofilm formation and the prevalence of MDR bacteria associated with infected wounds hint at a public health threat that needs immediate attention. Thus, a more balanced and comprehensive wound management approach and antimicrobial stewardship program are essential in the study setting.

Peritonitis-related bacterial infections: a large-scale case-series retrospective study in 160 domestic animals (2009-2022).

Bacterial peritonitis infections comprise a life-threatening clinical condition in domestic animals that commonly lead to sepsis and high mortality. A set of bacterial pathogens have been identified in septic peritonitis in livestock and companion animals. Nonetheless, most descriptions are restricted to case reports or limited to only one domestic species, and a restrict number of comprehensive studies involving this infection has focused on a great number of domestic animals. Here, we retrospectively investigated selected epidemiological data (with an emphasis in outcome), clinical signs, bacteriological culturing, and in vitro antimicrobial susceptibility patterns of microorganisms isolated of peritoneal fluid from 160 domestic animals (2009-2023) compatible with septic peritonitis. Bacteria were isolated from 71.9% (115/160) of the peritoneal fluid from 75 dogs (75/115 = 65.2%), 22 cats (22/115 = 19.1%), 14 horses (14/115 = 12.2%), and 4 cattle (4/115 = 3.5%). Among animals with bacterial isolation, Escherichia coli (34/115 = 29.6%), alfa-hemolytic Streptococcus (12/115 = 10.4%), Staphylococcus aureus (8/115 = 6.9%), beta-hemolytic Streptococcus (7/115 = 6.1%), and Pasteurella multocida (6/115 = 5.2%) were predominant in pure culture, in addition to a miscellaneous of other bacteria isolated in minor frequency, e.g., Pseudomonas sp., Trueperella pyogenes, Klebsiella pneumoniae, and Salmonella sp. In general, in vitro susceptibility tests of isolates revealed that florfenicol, chloramphenicol, and amoxicillin/clavulanic acid showed moderate effectivity (≥ 60%). Conversely, most of isolates exhibited resistance mainly to trimethoprim/sulfamethoxazole, enrofloxacin, and penicillin (> 60%). Additionally, multidrug resistance was found in 42.6% (49/115) of the isolates. Data related to the outcome were available in 37.4% (43/115) of animals that had bacterial isolation and, from these, the mortality rate was 79.1% (34/43), with a significant association (p < 0.036) between mortality and septic peritonitis by gram-negative bacteria. Neoplasia (7/43 = 16.3%), pneumonia/pulmonary abscess (5/43 = 11.6%), hepatitis (5/43 = 11.6%), metritis/pyometra (4/43 = 9.3%), and gall bladder rupture (3/43 = 7%) represented the probable main sources of septic peritonitis. Anorexia (34/115 = 29.6%), emesis (29/115 = 25.2%), lethargy (26/115 = 22.6%), respiratory distress (25/115 = 21.7%), ascites (20/115 = 17.4%), and fever (19/115 = 16.5%) were the most frequent clinical signs among animals with bacterial isolation. A variety of bacteria were isolated in the peritoneal fluid of animals, with a predominance of Enterobacteriaceae, streptococci, and staphylococci, highlighting the opportunistic nature of the pathogens in septic peritonitis. High in vitro multidrug resistance of isolates and high mortality of animals reinforce the need for early diagnosis and therapy based on the in vitro antimicrobial profile of the pathogens involved in septic peritonitis. Our results contribute to the etiological characterization, clinical-epidemiological findings, and vigilance of multidrug-resistant bacteria in septic peritonitis among livestock and companion animals.

Prevalence, Risk Factors, and Antimicrobial Resistance of Staphylococcus and Streptococcus Species Isolated from Subclinical Bovine Mastitis.

Subclinical mastitis (SCM) is a prevalent serious disease among dairy cows worldwide. It poses a significant challenge to the dairy industry, animal welfare, and a threat to public health. The present study aimed to investigate the molecular detection, prevalence, and antimicrobial resistance of Staphylococcus spp. and Streptococcus spp. isolated from raw composite milk samples obtained from SCM dairy cattle in Bangladesh. A total of 612 quarters milk samples obtained from 153 cows were analyzed for SCM using the California Mastitis Test. Bacterial isolation and identification were carried out and bacterial species were confirmed using molecular polymerase chain reaction methods. Antimicrobial susceptibility testing was performed using disc diffusion method. The findings revealed that the prevalence of SCM was 70.3% (26/37), 35.95% (55/153), and 23.04% (141/612) in the herd, cow, and quarter levels, respectively. Among the positive samples, 92.7% (51/55) were Staphylococcus spp. (S. aureus, S. chromogenes, and S. simulans) and the remaining isolates were 7.3% (4/55) Streptococcus spp. (Streptococcus agalactiae and Streptococcus dysgalactiae). The most prevalent species was S. chromogenes, accounting for 67.3% (37/55). Antimicrobial susceptibility testing showed that 65.5% of isolates were susceptible to cefoxitin, whereas, 89.1% were resistant to penicillin. Overall, 12 isolates (21.8%) out of 55 were resistant to more than three classes of antimicrobials and were defined as multidrug-resistant isolates. Methicillin-resistance gene was detected in 61.1% of the cefoxitin-resistant isolates. A multivariate logistic regression analysis identified five potential risk factors including the lack of post-milking teat disinfection (OR: 3.06), absence of immediate feeding after milking (OR: 9.81), poor udder hygiene (OR: 7.83), tick infestation (OR: 13.76), and absence of dry cow therapy (OR: 3.31). The findings of the current study underscore the urgent requirement for targeted interventions, considering the identified factors to effectively manage and control SCM in dairy cows.

Isolation, Antibacterial Activity and Molecular Identification of Avocado Rhizosphere Actinobacteria as Potential Biocontrol Agents of Xanthomonas sp.

Actinobacteria, especially the genus Streptomyces, have been shown to be potential biocontrol agents for phytopathogenic bacteria. Bacteria spot disease caused by Xanthomonas spp. may severely affect chili pepper (Capsicum annuum) crops with a subsequent decrease in productivity. Therefore, the objective of the study was to isolate rhizospheric actinobacteria from soil samples treated by physical methods and evaluate the inhibitory activity of the isolates over Xanthomonas. Initially, soil samples collected from avocado tree orchards were treated by dry heat air and microwave irradiation; thereafter, isolation was implemented. Then, antibacterial activity (AA) of isolates was evaluated by the double-layer agar method. Furthermore, the positive/negative effect on AA for selected isolates was evaluated on three culture media (potato-dextrose agar, PDA; yeast malt extract agar, YME; and oat agar, OA). Isolates were identified by 16S rRNA sequence analysis. A total of 198 isolates were obtained; 76 (series BVEZ) correspond to samples treated by dry heat and 122 strains (series BVEZMW) were isolated from samples irradiated with microwaves. A total of 19 dry heat and 25 microwave-irradiated isolates showed AA with inhibition zones (IZ, diameter in mm) ranging from 12.7 to 82.3 mm and from 11.4 to 55.4 mm, respectively. An increment for the AA was registered for isolates cultured on PDA and YME, with an IZ from 21.1 to 80.2 mm and 14.1 to 69.6 mm, respectively. A lower AA was detected when isolates were cultured on OA media (15.0 to 38.1 mm). Based on the 16S rRNA gene sequencing analysis, the actinobacteria belong to the Streptomyces (6) and Amycolatopsis (2) genera. Therefore, the study showed that microwave irradiation is a suitable method to increase the isolation of soil bacteria with AA against Xanthomonas sp. In addition, Streptomyces sp. BVEZ 50 was the isolate with the highest IZ (80.2 mm).

Bacterial Co-Infections and Antibiotic Resistance in Urinary Tract Infection of Covid-19 Patients in Erbil City

The COVID-19 pandemic has raised concerns over secondary infections because it has limited treatment options and empiric antimicrobial treatment poses serious risks of aggravating antimicrobial resistance. Many studies have shown that COVID-19 patients are predisposed to developing secondary infections. The prevalence of urinary tract infections (UTI) was evaluated in 248 patients admitted to different hospitals in Erbil city, Iraq. Results showed 138 (55.65%) patients were positive for bacterial growth, of which 72 isolates of Gram-negative and 66 isolates of Gram-positive bacteria were isolated and identified from the urine of COVID-19 patients depending on the 16S rRNA gene using PCR. The predominant obtained bacteria were Staphylococci species, of which isolates belong to 6 species, and the predominant Gram-negative species was Pseudomonas spp. which belongs to 4 species. Also, their susceptibility to 15 antibiotics was tested and it was found that most of the Gram-negative isolates were highly resistant to ampicillin 66(91.66%), amoxicillin 60(83.33%), cephalexin 52(72.22%) and cefixime 50(69.44%). While the most effective antibiotic was imipenem, and with percentage of 26(36.11%), it also showed variable sensitivity to other antibiotics. For Gram-positive bacteria, the highest resistance was against cefixime 40(60.60%), ampicillin 28(42.42%), and 18(27.27%) for both amoxicillin and ciprofloxacin, while the most effective antibiotic was gentamicin, which showed effectiveness against all the Gram-positive isolates. Another part of the study concerned with detection of the existence of ESBLs genes responsible for antibiotic resistance. The results revealed that all the isolates possessed the 16S rRNA gene, whereas blaTEM and blaCTX-M were found to be the most possessed genes in all the isolates, with a percentage of (88.33%).

Carbapenem resistance in gram-negative pathogens in an Iranian hospital: high prevalence of OXA-type carbapenemase genes.

The widespread dissemination of carbapenem-resistant Gram-negative bacteria poses a significant threat to global public health. This study aimed to investigate the prevalence of carbapenem resistance in Gram-negative bacteria isolated from patients at the Children's Medical Center Hospital, Tehran, Iran, to understand the molecular mechanisms underlying this resistance. During the period spanning from June 2019 to June 2020, 777 Gram-negative bacterial strains were isolated. Antibiotic susceptibility testing was performed according to Clinical and Laboratory Standards Institute. Polymerase chain reaction was used to detect carbapenem resistance genes including bla OXA23, bla OXA24, bla OXA48, bla OXA51, bla OXA58, bla OXA143, bla KPC, bla IMP, bla VIM, and bla NDM. Among the total bacterial isolates, 141 (18.1%) exhibited carbapenem resistance. Escherichia coli was the most prevalent (57.4%), followed by Klebsiella pneumoniae (11.3%) and Acinetobacter baumannii (10.6%). Other notable contributors included Enterobacter spp. (5.7%), Salmonella spp. (3.5%), and Stenotrophomonas maltophilia (2.8%). Citrobacter spp., Proteus mirabilis, and Pseudomonas aeruginosa contributed to the distributions of two, one, and three isolates, respectively. Notably, bla OXA48 showed the highest prevalence (33%), followed by bla OXA143 and bla OXA58 (27% and 24%, respectively). In addition, bla OXA24 was present in 11% of the total isolates, bla OXA23 in 10%, and bla NDM in 10%, whereas bla KPC, bla VIM, and bla IMP were not detected. Our study highlights the prevalence of carbapenemase-producing Gram-negative isolates among pediatric patients. Notable resistance patterns, especially in K. pneumoniae and E. coli, underline the urgent need for proactive interventions, including appropriate antibiotic prescription practices and strengthening of antibiotic stewardship programs.