Kirby-Bauer Disc Diffusion Method Research Articles

Cytotoxicity and antibacterial susceptibility assessment of a newly developed pectin–chitosan polyelectrolyte composite for dental implants

Biopolymers such as chitosan and pectin are currently attracting significant attention because of their unique properties, which are valuable in the food industry and pharmaceutical applications. These properties include non-toxicity, compatibility with biological systems, natural decomposition ability, and structural adaptability. The objective of this study was to assess the performance of two different ratios of pectin–chitosan polyelectrolyte composite (PCPC) after applying them as a coating to commercially pure titanium (CpTi) substrates using electrospraying. The PCPC was studied in ratios of 1:2 and 1:3, while the control group consisted of CpTi substrates without any coating. The pull-off adhesion strength, cytotoxicity, and antibacterial susceptibility tests were utilized to evaluate the PCPC coatings. In order to determine whether the composite coating was the result of physical blending or chemical bonding, the topographic surface parameters were studied using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). PCPC (1:3) had the highest average cell viability of 93.42, 89.88, and 86.85% after 24, 48, and 72 h, respectively, as determined by the cytotoxicity assay, when compared to the other groups. According to the Kirby–Bauer disk diffusion method for testing antibacterial susceptibility, PCPC (1:3) showed the highest average diameter of the zone of inhibition, measuring 14.88, 14.43, and 11.03 mm after 24, 48, and 72 h of incubation, respectively. This difference was highly significant compared to Group 3 at all three time periods. PCPC (1:3) exhibited a significantly higher mean pull-off adhesion strength (521.6 psi) compared to PCPC (1:2), which revealed 419.5 psi. PCPC (1:3) coated substrates exhibited better surface roughness parameters compared to other groups based on the findings of the AFM. The FTIR measurement indicated that both PCPC groups exhibited a purely physical blending in the composite coating. Based on the extent of these successful in vitro experiments, PCPC (1:3) demonstrates its potential as an effective coating layer. Therefore, the findings of this study pave the way for using newly developed PCPC after electrospraying coating on CpTi for dental implants.

Identification and Antimicrobial Susceptibility Patterns of Neisseria gonorrhoeae, Ureaplasma spp. and Mycoplasma spp. Isolated from Tribal Women

Sexually transmitted infections (STIs) are a major public health problem worldwide with significant social and economic implications. Effective control and prevention strategies necessitate a thorough understanding of the prevalence, isolation, and identification of STI pathogens. The present study aims to provide a comprehensive analysis of the isolation, identification, prevalence, and antimicrobial susceptibility pattern of STI pathogens based on culture method analysis. Endocervical /vaginal swab samples from female patients symptomatic for STI were cultured on different selective and differential media and pathogens were identified by colony morphology and biochemical tests. Antimicrobial Susceptibility Test (AST) of isolated and identified culture pathogen was performed by using Kirby-Bauer disc diffusion method. Among 209 endocervical/vaginal swab samples from symptomatic patients, 126 (60.28%) tested positive and 83 (39.71%) negative. Ureaplasma spp. (n = 100) was the most prevalent isolate, constituting 79.36% of culture-positive samples, followed by N. gonorrhoea (n = 99) at 78.57%, and Mycoplasma spp. (n = 41) at 32.54% individually and in combination. AST analysis revealed erythromycin (74%), ofloxacin (69%), and roxithromycin (64%) as the most resistant antibiotics for Ureaplasma spp. N. gonorrhoea showed the highest resistance to cefixime (78.79%), followed by ofloxacin (75.76%) and erythromycin (69.7%). Azithromycin and erythromycin exhibited 100% resistance against Mycoplasma spp. The study provides information on the prevalent bacterial pathogens involved in STIs among women in Anuppur and Shahdol districts, Madhya Pradesh. Understanding the diversity, distribution patterns and antibiotic sensitivity of these pathogens is crucial for developing targeted interventions and effective prevention strategies in such resource-limited areas.

Antimicrobial Resistance of Enterococcus Isolates from Poultry Farms in the Republic of Serbia (Autonomous Province of Vojvodina)

Enterococcus species are significant intestinal commensals of animals, including poultry. However, they have emerged as important opportunistic infective agents in both veterinary and human medicine as well as major nosocomial pathogens, owing to their increasing antimicrobial resistance. This research aimed to investigate the prevalence and antimicrobial resistance patterns of Enterococcus spp. isolated from poultry farms in the north of Serbia. A total of 40 samples of overshoes or feces were collected from 40 poultry farms and analyzed for the presence of Enterococcus spp. using PCR or MALDI-TOF mass spectrometry for their identification. The number of isolates was 40 and included 11 isolates from laying hens, 2 isolates from turkeys, 3 from broiler breeders, and 24 from broilers. The Kirby–Bauer disk diffusion method was used to test for antibiotic susceptibility in accordance with the Clinical and Laboratory Standards Institute and EUCAST guidelines. The results showed that Enterococcus faecalis was isolated from 37.5% farms, and E. faecium from 42.5%. E. hirae was identified in 15% of poultry establishments, and E. durans and E. thialandicus on 2.5%. Notably, resistance to erythromycin, streptomycin, fluoroquinolones, and tetracyclines among the frequently used antibiotics was found. Furthermore, 35% of the isolates had multidrug resistance (MDR). In order to prevent the spread of antibiotic resistance in chicken farming and protect the health of the public and animals alike, our findings highlight the critical need for improved surveillance and control measures. To effectively establish a containment strategy for Enterococcus spp. isolated from poultry farms, more research into the processes behind their antibiotic resistance is required.

Evaluation of Fosfomycin in-vitro susceptibility among gram negative isolates from urine culture in a tertiary care hospital in Lucknow

The rise of bacteria that are Multidrug- resistant or Extended Drug Resistant (MDR or XDR) and the lack of novel antibiotics have wreaked havoc on patient treatment options. Fosfomycin has just recently come to light because of the development of resistance to existing drugs. This study aims to evaluate the Fosfomycin susceptibility of Gram- negative isolates in vitro. A prospective study done in the Department of Microbiology, Integral Institute of Medical Sciences of Research, Lucknow, over a period of six months from April 2023 to September 2023. A total of 1328 urine samples were processed in microbiology lab and after identification of urinary isolates, antibiotic susceptibility testing was performed, and results were interpreted following the Clinical and Laboratory Standards Institute guidelines (CLSI). Fosfomycin sensitivity was tested by the Kirby-Bauer disc diffusion method. 353 of the 1328 processed urine samples showed a growth of pathogens. 184 (52.1%) of the isolates were Gram-negative, while 169 (47.8%) were Gram-positive. Fosfomycin (7%) and Nitrofurantoin (13%) showed lower rates of resistance among these isolates. Relatively higher rates of resistance were observed for Doripenem (17%), Meropenem (17%), Imipenem (18%), Amikacin (18%), Gentamicin (27.9%). Norfloxacin, Aztreonam, Cefepime, Ciprofloxacin and Levofloxacin and Cotrimoxazole showed a high resistance rate of 46.2%, 48.8%, 50%, 60.4%, 61% and 70% respectively. Fosfomycin's low resistance (7%) to the antibiotic indicates that it works well as a urinary antibiotic. Uropathogenic Enterobacteriaceae isolates exhibited an excellent level of in vitro susceptibility to Fosfomycin. These in vitro results highlight the unexplored possibilities of Fosfomycin as a superior therapeutic option for the treatment of UTIs, and it has a good chance of expanding into a safe and effective oral alternative treatment that can be used in inpatient as well as outpatient settings.

BACTERIOLOGICAL PROFILE AND ANTIBIOGRAM OF GRAM-NEGATIVE BACILLI ISOLATED FROM ENDOTRACHEAL TUBE SECRETIONS AND TRACHEAL ASPIRATES FROM PATIENTS ON MECHANICAL VENTILATION: A HOSPITAL-BASED CROSS-SECTIONAL STUDY

Objective: Nosocomial infections have become a serious threat to mortality and morbidity among hospitalized patients. Major risk factor among critically ill patients is excessive use of invasive devices like Endotracheal tube (ET) and tracheal intubation. The development of biofilm and their subsequent dislodgement aids in lung colonization and may cause Ventilator-associated pneumonia (VAP) [1]. Methods: Present study was conducted on ET tube tips and Tracheal aspirates received in microbiological laboratory from various ICU’s (Medical, surgical and pediatric) in Andhra Medical College, Visakhapatnam over a period of one year from September 2022 to August 2023. A total of 116 samples were processed according to standard protocols and Antibiotic Susceptible Testing (AST) was performed by Kirby-Bauer disc diffusion method on Mueller-Hinton agar as per CLSI guidelines. Results: In total, 116 samples were processed. ET tube tips were 76/116 and tracheal aspirates were 40/116, with males (69/116) outnumbered females (47/116). Out of a total of 116 samples, 72 (62%) were culture-positive and 44 (38%) were sterile. Acinetobacter spp. was the most common pathogen among 72 culture positives (31/72, 43%), followed by Klebsiella spp. (20/72, 28%), Pseudomonas spp. (13/72, 18%) and Escherichia coli (8/72, 11%). A total of 11 (11/72, 15%) GNB were found as multi-drug resistant. The multi-drug resistant GNB isolated were Acinetobacter (6/72), Klebsiella (3/72) and Pseudomonas (2/72). Meropenem is the most susceptible antibiotic, followed by Piperacillin-Tazobactam. Conclusion: It was concluded from this study that most commonly isolated pathogen was Acinetobacter spp. Most of these isolates were sensitive to Carbapenem and BLBLI combination drugs. Microbial persistence and impaired response to the treatment were more frequent, when multi-drug resistant organisms were present. Hence a local combined antibiotic approach, based on bacteriological profile and AST is essential to initiate empirical therapy which will minimize the bacterial colonization and prevent the incidences of VAP.

Epidemiology of cryptococcal meningitis and fluconazole heteroresistance in Cryptococcus neoformans isolates from a teaching hospital in southwestern China.

Cryptococcal meningitis (CM), a common and serious opportunistic infection mostly caused by Cryptococcus neoformans, is primarily treated with fluconazole. Nevertheless, Cryptococcus neoformans strains that undergo repeated exposure to azoles can gradually acquire heteroresistance to fluconazole. The management of this specific CM infection poses a substantial challenge. Determining a globally accepted definition for fluconazole heteroresistance and developing effective and prompt methods for identifying heteroresistance is of utmost importance. We collected data on the clinical and epidemiological characteristics of patients diagnosed with CM. All the available Cryptococcus neoformans strains isolated from these patients were collected and subjected to antifungal susceptibility testing and evaluation of fluconazole heteroresistance. AIDS was present in 40.5% of the patients, whereas 24.1% did not have any underlying diseases. Patients with chronic diseases or impaired immune systems are susceptible to infection by Cryptococcus neoformans, a fungus that frequently (39.6%, 19/48) shows heteroresistance to fluconazole, as confirmed by population analysis profile (PAP).IMPORTANCEFluconazole heteroresistance poses a significant threat to the efficacy of fluconazole in treating cryptococcal meningitis (CM). Unfortunately, the standard broth microdilution method often misses the subtle percentages of subpopulations exhibiting heteroresistance. While the population analysis profile (PAP) method is esteemed as the gold standard, its time-consuming and labor-intensive nature makes it impractical for routine clinical use. In contrast, the Kirby-Bauer (KB) disk diffusion method offers a simple and effective screening solution. Our study highlights the value of KB over PAP and minimum inhibitory concentration (MIC) by demonstrating that when adjusting the inoculum concentration to 1.0 McFarland and subjecting samples to a 72-hour incubation period at 35°C, the KB method closely mirrors the outcomes of the PAP approach in detecting fluconazole heteroresistance. This optimization of the KB method not only enhances assay efficiency but also provides a blueprint for developing a timely and effective strategy for identifying heteroresistance.

A facile method to fabricate superhydrophobic cotton fabrics finished using water-proof and antibacterial agent

Superhydrophobic emulsions (SHEs) based on fatty acids (stearic, palmitic, myristic and lauric acids)-melamine (FAMEs) was synthesized without emulsifier and applied on cotton fabric. The superhydrophobic compounds (FAME1, FAME2, FAME3 and FAME4) were successfully prepared on the basis of the reaction between fatty acid anhydrides and melamine. The chemical structures of the prepared FAME compounds were investigated using FTIR,1HNMR spectroscopy and elemental analysis. The cotton fabric samples were treated with the prepared emulsions using different concentrations in the range of 20 – 60 g/L. Hydrostatic pressure, water contact angle (WCA) and water permeability tests were performed on the treated samples. It was shown that super hydrophobicity of the fabric treated with stearic acid-melamine emulsion (60 g/L) recorded the best results due to the combined effect of surface roughness imparted by melamine and the low surface energy of stearic acid. Furthermore, antibacterial agent Biochrol WS1 in concentrations (2 and 8%) was simultaneously applied to the treated samples. The Kirby-Bauer disc diffusion method was used to estimate the biological activity of the treated cotton. Two strains of bacteria: Gram-positive (Bacillus subtilis - Staphylococcus aureus) and Gram-negative (Escherichia coli-Pseudomonas aeruginosa) were used for this purpose. The tensile strength of treated samples was measured as well. The results showed that the antibacterial and water-proof fabrics can be achieved by applying selected material without significant changes on their comfort properties.

Colistin-, cefepime-, and levofloxacin-resistant Salmonella enterica serovars isolated from Egyptian chicken carcasses

ObjectivesThe emergence of multidrug-resistant (MDR) Salmonella strains, especially resistant ones toward critically important antimicrobial classes such as fluoroquinolones and third- and fourth-generation cephalosporins, is a growing public health concern. The current study, therefore, aimed to determine the prevalence, and existence of virulence genes (invA, stn, and spvC genes), antimicrobial resistance profiles, and the presence of β-lactamase resistance genes (blaOXA, blaCTX-M1, blaSHV, and blaTEM) in Salmonella strains isolated from native chicken carcasses in Egypt marketed in Mansoura, Egypt, as well as spotlight the risk of isolated MDR, colistin-, cefepime-, and levofloxacin-resistant Salmonella enterica serovars to public health.MethodsOne hundred fifty freshly dressed native chicken carcasses were collected from different poultry shops in Mansoura City, Egypt between July 2022 and November 2022. Salmonella isolation was performed using standard bacteriological techniques, including pre-enrichment in buffered peptone water (BPW), selective enrichment in Rappaport Vassiliadis broth (RVS), and cultivating on the surface of xylose-lysine-desoxycholate (XLD) agar. All suspected Salmonella colonies were subjected to biochemical tests, serological identification using slide agglutination test, and Polymerase Chain Reaction (PCR) targeting the invasion A gene (invA; Salmonella marker gene). Afterward, all molecularly verified isolates were screened for the presence of virulence genes (stn and spvC). The antimicrobial susceptibility testing for isolated Salmonella strains towards the 16 antimicrobial agents tested was analyzed by Kirby–Bauer disc diffusion method, except for colistin, in which the minimum inhibition concentration (MIC) was determined by broth microdilution technique. Furthermore, 82 cefotaxime-resistant Salmonella isolates were tested using multiplex PCR targeting the β-lactamase resistance genes, including blaOXA, blaCTX-M1, blaSHV, and blaTEM genes.ResultsSalmonella enterica species were molecularly confirmed via the invA Salmonella marker gene in 18% (27/150) of the freshly dressed native chicken carcasses. Twelve Salmonella serotypes were identified among 129 confirmed Salmonella isolates with the most predominant serotypes were S. Kentucky, S. Enteritidis, S. Typhimurium, and S. Molade with an incidence of 19.4% (25/129), 17.1% (22/129), 17.1% (22/129), and 10.9% (14/129), respectively. All the identified Salmonella isolates (n = 129) were positive for both invA and stn genes, while only 31.8% (41/129) of isolates were positive for the spvC gene. One hundred twenty-one (93.8%) of the 129 Salmonella-verified isolates were resistant to at least three antibiotics. Interestingly, 3.9%, 14.7%, and 75.2% of isolates were categorized into pan-drug-resistant, extensively drug-resistant, and multidrug-resistant, respectively. The average MAR index for the 129 isolates tested was 0.505. Exactly, 82.2%, 82.2%, 63.6%, 51.9%, 50.4%, 48.8%, 11.6%, and 10.1% of isolated Salmonella strains were resistant to cefepime, colistin, cefotaxime, ceftazidime/clavulanic acid, levofloxacin, ciprofloxacin, azithromycin, and meropenem, respectively. Thirty-one out (37.8%) of the 82 cefotaxime-resistant Salmonella isolates were β-lactamase producers with the blaTEM as the most predominant β-lactamase resistance gene, followed by blaCTX-M1 and blaOXA genes, which were detected in 21, 16, and 14 isolates respectively).ConclusionThe high prevalence of MDR-, colistin-, cefepime-, and levofloxacin-resistant Salmonella serovars among Salmonella isolates from native chicken is alarming as these antimicrobials are critically important in treating severe salmonellosis cases and boost the urgent need for controlling antibiotic usage in veterinary and human medicine to protect public health.Graphical

Prevalence, antimicrobial susceptibility profiles and resistant gene identification of bovine subclinical mastitis pathogens in Bangladesh

Subclinical mastitis (SCM), a silent threat in the dairy sector of Bangladesh poses a significant economic impact and serves as a potential source of infection for healthy cows, hindering efforts to achieve milk self-sufficiency. Despite the importance of this issue, limited research has been conducted on mastitis in Sylhet region of Bangladesh. This study aimed to investigate the molecular prevalence, antimicrobial susceptibility profile and resistant genes detection on pathogens (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) causing SCM. In a cross-sectional study utilizing convenience sampling, 325 milk samples were collected from apparently healthy dairy cows. Initially, SCM was detected using the modified Whiteside test (MWST) method. Suspected positive samples were then subjected to bacteriological culture and standard biochemical assays, followed by molecular identification through polymerase chain reaction (PCR). Finally, antimicrobial susceptibility testing was conducted on all PCR-positive samples using the Kirby-Bauer disk diffusion method on Mueller-Hinton agar. In the Sylhet district, the prevalence of SCM was 64.92 % (211 out of 325) at the individual animal level and 82.69 % (43 out of 52) at the herd level. Among the SCM-positive animals, S.aureus was found in 31.75 % (67 out of 211) of cases, E.coli in 81.99 % (173 out of 211), and K.pneumoniae in 66.82 % (141 out of 211). K.pneumoniae had the highest prevalence at 60 % in Zakiganj, S.aureus at 45 % in Zakiganj, and E.coli at 72 % in Bishwanath Upazila. Extended spectrum beta lactamase (ESBL) genes blaTEM, blaOXA, blaCTX-M1,blaCTX-M2,MultiCaseDHA were identified. Additionally, antibiotic resistance genes tet(A), AAC(3)-iv, and Sul1 were also detected. The pathogens exhibited resistance to Penicillins (ampicillin, amoxicillin), Cephems (cefuroxime, ceftazidime), and Tetracyclines (tetracycline). However, all three bacteria were highly sensitive to meropenem, amikacin, gentamicin, ciprofloxacin, and sulfamethoxazole-trimethoprim. These findings highlight the critical need for targeted antimicrobial stewardship and effective control measures to mitigate the impact of SCM on dairy production and animal health in the Sylhet region of Bangladesh.

Distribution Patterns and Antibiotic Resistance Profiles of Bacterial Pathogens Among Patients with Wound Infections in the Jiaxing Region from 2021 to 2023.

To systematically assess the distribution and antimicrobial susceptibility of pathogens in wound infections, and analyze risk factors associated with multidrug resistance (MDR). Retrospectively analyzing Jiaxing-region medical records between January 2021 and December 2023, we identified a cohort of 461 wound infection patients. Cultures were grown on various agars, with bacteria identified via Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. The antimicrobial susceptibility of the organisms were conducted by VITEK 2 system, Kirby-Bauer disk diffusion method and Epsilometer test. Statistical Package for the Social Sciences (SPSS) version 22 was used for statistical analysis. Multivariable logistic regression models were developed to pinpoint risk factors for multidrug-resistant organism (MDRO) infections and predict occurrences. From 461 patients, 549 bacterial pathogens were isolated, predominantly consisting of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Enterobacter cloacae, and Enterococcus faecalis. Vancomycin, linezolid, and tigecycline maintained their efficacy against Staphylococcus aureus and Enterococcus species, while Pseudomonas aeruginosa demonstrated sensitivity to aminoglycosides. Conversely, Escherichia coli exhibited high amoxicillin resistance (85.4%). More than half of the isolates were resistant to levofloxacin, ceftriaxone, cotrimoxazole, and gentamicin, with Acinetobacter baumannii strains showing considerable resistance (65.8-68.4%) to advanced cephalosporins and carbapenems. Within this group, 58 MDROs were detected, primarily originating from Burn Plastic Surgery, Emergency, and Intensive Care Unit (ICU) departments. Multivariate logistic regression identified hyperglycemia, hypoalbuminemia, surgery, extended hospitalization, and exposure to multiple antibiotic classes as independent risk factors for MDRO wound infections. Based on these findings, a predictive model for MDRO occurrence in wounds was constructed, which had a sensitivity of 0.627, specificity of 0.933, and an Area Under the Curve (AUC) of 0.838. Staphylococcus aureus and Pseudomonas aeruginosa dominated in wound infections with differential antibiotic resistance. Independent risk factors included hyperglycemia, hypoalbuminemia, surgery, extended hospitalization, and polyantibiotic use. We urge prioritizing culture, susceptibility tests, and personalized antibiotic strategies to address MDRO risks and improve wound infection management specificity and efficacy.

Spatial Distribution of Faecal Indicator Bacteria around Kanyakumari Coast, Southernmost point of Mainland India.

Coastal and marine ecosystems should be sustained by maintaining the better environmental quality for our well-being. The goal of this study was to assess the water quality on the coastlines of Kanyakumari, the southernmost part of Indian mainland. Distribution and abundance of indicator bacteria and opportunistic pathogens related to fecal contamination and antibiotic resistance of the isolates were studied to observe the influence of anthropogenic pressures on coastal waters. Water samples were collected from July’22 to September‘22 from three different ecosystems: Chinnamuttom harbor, Kovalam coast and Manakudy estuary. At each site physio–chemical parameters were noted. Simple main effects analysis showed that the sites have a statistically significant difference in total viable count and total coliform count (p < 0.05). A total of eight indicator bacteria such as E. coli, Klebsiella sp., Enterococcus sp., Aeromonas sp., Proteus mirabilis, Salmonella typhi, Vibrio cholerae and Vibrio paraheamolyticus were identified. Antibiotic sensitivity test by Kirby-Bauer Disk Diffusion method was performed to identify sensitivity pattern of antibiotics. The isolates were exposed to ten antibiotics. All the isolates were resistant to at least one antibiotic, and penicillin was the predominant. Presence of fecal indicators indisputably reveals that the chosen sites are receiving untreated sewage loaded with fecal matter which might have detrimental effect on coastal waters.

Prevalence and antimicrobial resistance of salmonellae isolated from eggs of local chicken in selected towns of Ethiopia.

Salmonellosis is one of the most common food-borne diseases in industrialised and developing countries. In recent year, an increase in antimicrobial resistance among different Salmonella serotypes has been observed. A cross-sectional study was conducted to assess the prevalence and antimicrobial susceptibility of Salmonella isolated from local chicken eggs in four selected towns in Ethiopia. A total of 115 eggs were examined to detect Salmonella by using standard microbiological methods. The susceptibilities of the isolates to nine antimicrobials were tested by the Kirby-Bauer disk diffusion method. The study revealed that of the 115 eggs examined, 22 (19.1%) were positive for Salmonella of which 14 (12.2%) and 8 (7%) of the isolates were from shells and contents, respectively. The occurrence of Salmonella in egg shells and content and between different altitudes did not differ significantly (p > 0.05). Most isolates were resistant to more than three antimicrobials with a high resistance to kanamycin, ampicillin, nalidixic acid, cotrimoxazole, oxytetracycline and chloramphenicol. The results indicate the potential importance of local chicken eggs as source of multiple antimicrobial-resistant salmonellae and the need for proper cooking before consumption. Further studies are required to describe the epidemiology of Salmonella in various agroclimatic zones of Ethiopia.

ANTIMICROBIAL EFFECT OF CLOVES (Syzygium aromaticum) ON Escherichia coli FROM FEMALE ADULTS URINE WITHIN ALUU COMMUNITY, RIVERS STATE, NIGERIA.

The study was aimed at determining the antimicrobial effect of clove on Escherichia coli isolated from the urine of female adults in Aluu community, Rivers State. Clean-void, mid-stream urine (MSU) specimens were collected from 30 female adults and 20 pregnant women residing in Aluu community, Port Harcourt Rivers state. The samples were culture on Eosin Methylene Blue (EMB) agar by streaking method. Biochemical test was carried out on the isolated bacteria using Bergey’s Manual of Bacteriological Identification. Antibiogram of the isolated bacteria were determined by Kirby-Bauer disc diffusion method. Antimicrobial activity of clove extract was determined by well-in-agar method. Among the 30 sample of the adult female, only 20% of the urine sample were positive for the presence of Escherichia coli while 80% were devoid of Escherichia coli. In the case of urine sample from pregnant women, Escherichia coli was isolated from 45% of the sample while 55% of the sample showed no presence of Escherichia coli. The result of the antibiotic sensitivity showed that 14% of Escherichia coli were resistant to ofloxacin, 33% resistant to perfloxacin, 60%, resistant to augmentin, 74% resistant to nitrofurantoin, 73%, resistant to ceftazidime, 93% resistant to Nalidixic acid and 33% were resistant to gentamin. The antimicrobial activity of cloves produced zone inhibition ranged from 11.50±0.71 to 17.50±0.71mm of all the tested isolated. The antimicrobial potential of clove in the treatment of urinary tract infection by Escherichia coli was also shown in this study, hence could be applied in the treatment of urinary tract infections.

A Quick, High-Yield Biogenic Synthesis of Antibacterial AgNPs (Silver Nanoparticles) via Carica papaya Seeds

Carica papaya seeds were used in this research for the synthesis of AgNPs. The production of silver nanoparticles was characterized using UV–Vis spectroscopy, FTIR, XRD and SEM-EDX analysis. The antibacterial activity of the prepared AgNPs was evaluated by the Kirby–Bauer disc diffusion method with the antibacterial activity of different compounds against Bacillus aerogenes. UV–Vis spectral peaks are found at 8–18 nm. SEM and TEM analysis revealed several spherical structures between 10 nm and 50 nm. XRD analysis also confirmed its 50 nm size. Experimental data revealed that AgNPs inhibited bacterial growth. This study shows that papaya seed extract contributes to the bioreduction and stabilization of the synthesized silver nanoparticles.

In vitro antimicrobial activity of silver nanoparticles against selected Gram-negative and Gram-positive pathogens

Background and aim. Infections caused by pathogenic bacteria increase patient morbidity and mortality and significantly raise treatment costs. The use of silver nanoparticles as an alternative treatment for S aureus, E coli, MRSA, E faecalis, K pneumoniae and P aeruginosa indicates their antibacterial effect and prompts medical research to consider the next generation of antibacterial drugs that could change antibiotic therapy. By combining silver nanoparticles with different classes of antibiotics, the antibacterial effect is evidenced by increased values of the inhibition zone compared to the values obtained for some antibiotics commonly used in the treatment of bacterial infections. This study focuses on comparing the antibacterial activity of antibiotics versus antibiotics combined with silver nanoparticles against various bacteria, by comparing inhibition zones obtained for both. We aim to prove that the size of the inhibition zone for antibiotics combined with silver nanoparticles is greater, thus confirming the improved antibacterial effect. Metods. In this study we tested the antibacterial activity of solutions of silver nanoparticles alone or in combination with different antibiotics. We used standard bacterial strains, ATCC, both Gram positive bacteria Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, as well as Gram negative bacteria Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, but also on clinical isolates: a strain MRSA (Methicillin Resistant Staphylococcus aureus) and a PDR strain (pan drug resistant) of Klebsiella pneumoniae. Bacterial identification was performed using Vitek MS analyzer (bioMerieux). Antibiotic susceptibility determination was performed with VITEK2 COMPACT SYSTEM (bio Merieux, Inc Durham NC) with ready to use VITEK AST cards. The interpretation of the results was done in compliance with EUCAST 2023-2024 standards. Testing was performed for several classes of antibiotics, silver nanoparticle solutions in 2 concentrations (10 μg/mL and 100 μg/mL) and for combinations of antibiotics with silver nanoparticle solutions. The diameter of the inhibition zone (ZOI) for silver nanoparticles, antibiotics and silver nanoparticles combined with antibiotic against each bacterium was expressed in millimeters. The Kirby-Bauer disk-diffusion method, in accordance with current EUCAST standards, was used to analyze the antibacterial effect of antibiotics, silver nanoparticles, and antibiotics combined with silver nanoparticles at biocompatible doses of 10 and 100 μg/mL. The experiments were conducted in triplicate, and the results were almost identical. Results. The results of this study show that the silver nanoparticles displayed antibacterial activity, proven by the appearance of the inhibition zone, in various sizes, for all bacteria studied. The antibiotic classes tested were beta-lactamins, first, second, third and fourth generation cephalosporins, macrolides, fluoroquinolones, lincosamides, aminoglycosides, glycopeptides, tetracyclines, oxazolidinones, sulfonamides, rifamycins, amphenicols. Testing S aureus ATCC 29213, the highest zone of inhibition was demonstrated for cephalosporins (32.6667 ± 0.701 mm), macrolides (31.6667 ± 0.701 mm, and lincosamides (29.6667 ± 0.701 mm). Testing MRSA (internal code GR0333), the highest zone of inhibition for combination of silver nanoparticles and antibiotics was demonstrated for fluoroquinolones (36.3333 ± 0.701 mm), lincosamides (32.3333 ± 0.701 mm), Fusid acid (32.3333 ± 0.701 mm) and aminoglicosides (31.3333 ± 0.701 mm). Testing E coli ATCC 25922 the highest zone of inhibition was for Fosfomycine, 39 mm and for E faecalis ATCC 29212 for aminoglicosides was 19 mm. For K pneumoniae (internal code GQ8575) the inhibition zone for silver nanoparticles 100 μg/mL was 12.3333 ± 0.701 mm and for P aeruginosa ATCC 27253 was 16 ± 1.214 mm. Conclusions. The use of metallic nanoparticles, especially silver ones, as antimicrobial agents with definite bactericidal activity has led medical specialists to consider this new treatment which may change antibacterial therapy. Studies of in vitro combinations between silver nanoparticles and different classes of antibiotics represent a highly efficient and effective new antibacterial treatment against multidrug-resistant bacteria. To avoid the problem of antimicrobial resistance associated with conventional antibiotics, it is necessary to understand the adaptive mechanisms of bacteria under the action of metal nanoparticles, which could be exploited in future studies. Further in vitro and in vivo studies that would assess specify the biocompatibility and toxicity of silver nanoparticles will make these super nanomaterials the medicines of the future.

Phenotypic Screening and Antibiogram of Infectious Ulcerative Keratitis Cases in Tripoli Eye Hospital, Libya

Aims: This study to investigate the most prevalent pathogens that cause corneal ulcer in Tripoli-Libya, and to recognize the antibiogram of the isolated pathogens Study Design: This study was a prospective study performed in eye hospital (Zawyet-Aldahmany eye hospital). Place and Duration of Study: It was conducted at the microbiology laboratory of the hospital over a year from December 2018 to January 2020, The overall size of the sample enrolled in this study was 50 inpatients in the admission department, which was taken according to the incidence of the corneal ulceration cases admitted to the hospital. Methodology: The corneal scrapings and swabs were collected and subjected to microbiological examination. Demographic data and risk factors were collected for each patient. The antibiotic susceptibility of the bacterial microorganisms was determined by the Kirby-Bauer disk diffusion method, to identify the most appropriate antibiotic for each bacterial isolate. Results: 60% of the patients were males, the mean age of the patients was 46.5 years, unilateral right eye keratitis was involved in (54%) of cases, trauma was the major risk factor (24%), followed by systemic disease (14%). Concerning the seasonal distribution of the cases between months, our study revealed that summer and winter seasons in Libya (January, July, August, and September) involved most of the cases, and interestingly, fungal keratitis (Aspergillus) was higher in (July, August), which is the summer season in Libya. The culture positive rate was (80%), of which (36%) were bacterial, and (22%) were fungal pathogens, and the other (22%) were mixed fungal and bacterial cultures. The most common bacterial isolate was (26%) P.aeruginosa and (16%) staphylococcus aureus, while Aspergillus (40%) was the most common fungal isolate, followed by Penicillium and fusarium species. Our results showed that P.aeruginosa was the responsible microorganism for rapid keratitis progression in three cases who were using cosmetic lenses promptly. Concerning antibiotic sensitivity, all gram-negative bacteria and positive isolates were susceptible to old-generation fluoroquinolones such as ciprofloxacin and levofloxacin, while ceftazidime showed resistance to penicillins. Conclusion: In conclusion, with early suspicion and microbiological diagnostic procedures, appropriate therapy can only reduce the incidence of this threatening ocular case.

Characterization of Leuconostoc lactis Bacteremia during a 2-year Study at a Tertiary Care Center in North India-An Observational Analysis.

Leuconostoc species are regarded as important causes for many infections in immunocompromised patients. In this study, we assessed the characteristics of Leuconostoc spp. causing bacteremia in patients at our center. This observational analysis was conducted in the microbiology laboratory of a tertiary care center in northern India from July 2021 to July 2023. Patients in whom blood culture bottles were positive for Leuconostoc lactis were included in the study. Culture isolates were identified by MALDI-ToF MS as L. lactis and tested for antibiotic sensitivity results by Kirby-Bauer disk diffusion method. Demographic and clinical details were collected and analyzed. During the study period, 6,742 blood culture bottles flagged positive. Among these, L. lactis was isolated from 14 (0.21%) patients. The median patient age was 34 years. The male-to-female ratio was 2.5:1. All the patients with L. lactis bacteremia had an underlying condition leading to immunosuppression (e.g., carcinoma and chronic kidney disease). All the patients with L. lactis bacteremia had an intravascular device present at the time of bacteremia. All isolates in the study were sensitive to doxycycline, high level gentamicin, minocycline, ampicillin-sulbactam, and linezolid. Mortality was attributed to bacteremia by L. lactis in five patients. Appropriate and timely identification of the Leuconostoc species is important for the clinician to tailor regimens for the patients.

Prevalence and antimicrobial mechanism of carbapenem-resistant Klebsiella pneumoniae and its molecular properties

BackgroundThe carbapenem-resistant Klebsiella pneumoniae poses a serious threat to public health because carbapenems are used as a final resort to treat K. pneumoniae-mediated infections in humans. MethodsSamples were collected from various clinical specimens including skin swabs, anal swabs, wound swabs, oral swabs, and sputum by the standard method and K. pneumoniae strains were isolated. Biofilm-forming characters were determined. The antibiotic resistance pattern was analyzed by the Kirby–Bauer disk diffusion method. Carbapenem resistance properties were tested using the imipenem and meropenem antibiotics. The carbapenemase genes (blaKPC and blaNDM) were determined. ResultsA total of 11 cephalosporin-resistant K. pneumoniae (CRKP) strains were isolated from the samples. The screened CRKP strains exhibited multi-drug resistance and non-susceptible to imipenem, ceftazidime, piperacillin, ceftriaxone, cefazolin, ampicillin, aztreonam, and cefotetan antibiotics. A total of 79.4 % K. pneumoniae isolates showed positive results on String-forming test. About 82.1 % of isolates showed mucoid colonies and 59 % of K. pneumoniae strains formed biofilm (p < 0.01). Out of 11 isolates, four strains exhibited Klebsiella pneumoniae carbapenemase type, three strains produced metallo-β-lactamases (MBL), and four strains exhibited as carbapenemase types. A total of 63.5 % Klebsiella pneumoniae carbapenemase-producing strains showed very low MIC value (<0.05 mg/L). ConclusionsDrug-resistance K. pneumoniae was isolated from clinical specimens that were screened. The continuous monitoring of drug-resistance genes are required to make policy decisions.

Pediatric Urinary Tract Infections at a Tertiary Care Center: Microbial Diversity and Antibiotic Resistance Patterns

Abstract Introduction: Urinary tract infection (UTI) remains a prevalent bacterial infection among the pediatric age group, ranking as the third-most common bacterial infection in children in developing countries, following gastrointestinal and respiratory tract infections. It continues to pose a significant health challenge. Materials and Methods: The urine samples underwent gross examination, wet mount, and Gram stain. Semiquantitative cultures were conducted on conventional media (MacConkey agar, blood agar, and CLED agar) and UTI chromogenic media. Uropathogen identification employed standard microbiological techniques. Antibiotic susceptibility was determined using the Kirby–Bauer disk diffusion method, with interpretation based on CLSI guidelines. Plates were incubated overnight, and clear zone diameters around antibiotic discs were measured for sensitivity or resistance determination. Results: The study comprised 64.75% male children and 35.25% female children. Analyzing the age distribution, the majority of participants fell within the age range of 1–5 years (35%), followed by those &lt;1 year (33.75%), and the age group of 5–12 years, accounting for 31.25% of the total 400 participants. The findings from our investigation revealed a UTI prevalence of 17.25%, with Escherichia coli and Klebsiella emerging as the predominant uropathogens. Notably, these pathogens exhibited a significant susceptibility to carbapenems, nitrofurantoin, and amikacin. Conclusion: Our study identified a male predominance and various age distributions among UTI patients. Antibiotic susceptibility patterns revealed E. coli and Klebsiella pneumoniae’s high sensitivity to key antibiotics, whereas Enterococcus spp. exhibited significant high-level aminoglycoside resistance. This study underscores the importance of tailored antibiotic strategies based on local resistance profiles to combat UTIs effectively.

Prevalence and antibiotic susceptibility patterns of Escherichia coli and Staphylococcus aureus isolated from bioaerosols of local markets located in Agulu, Anambara State

There is a need for improved understanding of aerosol-acquired disease due to the increasing environmental load of antibiotic resistant bacteria. Multidrug-resistant Escherichia coli and Staphylococcus aureus are examples of bacteria for which the role of exposure to aerosolized organisms in disease transmission should be more closely evaluated globally. This study is aimed at evaluating the prevalence and antibiogram of S. aureus and E. coli present in market bioaerosols, located in Nwagu-Agulu, Anambra Nigeria. Impaction sample collection method was used to collect bioaerosol samples within the market using nutrient agar as the collection media, A combination of the cultural and microscopic features as well as selected biochemical tests were employed to identify the isolates. The Kirby-Bauer disk diffusion method was used to determine antibiotic resistance to selected commonly used antibiotics. A total of 76 S. aureus and 24 E. coli were isolated. Both organisms have been implicated in community-acquired infections. The most common bacteria isolated were Staphylococcus aureus. Varying levels of resistance were observed by these isolates to selected commonly use antibiotics. There is high prevalence of S. aureus and E. coli within Nwagu market Agulu, Anambra State, Eastern region of Nigeria. The organisms have very high rates of resistance to antibiotics (MDR) as reported by other workers. The government as well as Health professionals must play an important role in the prevention of community acquired infections via regular environmental monitoring of open markets bioaerosol and establishing a common permissible limits or concentration for bioaerosols within the markets.