Kirby-Bauer Disc Diffusion Method Research Articles

High prevalence of multidrug resistant and extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolated from urinary tract infections in the West region, Cameroon.

Antimicrobial resistance remains a worldwide health problem with serious societal and economical repercussions. Multidrug resistant and Extended-Spectrum β-Lactamase producing-Enterobacterales (ESBL-E) are pathogens of critical public health priority that urgently require the research and development of new drugs. This study aims to determine the prevalence and characterize the genes conferring resistance to β-lactams among Escherichia coli and Klebsiella pneumoniae isolated from patients with urinary tract infections (UTIs) in the West region, Cameroon. A cross-sectional study was conducted among two healthcare facilities during a four-month period from February to May, 2023. All mid-stream urine samples were collected from UTIs patients. The Escherichia coli and K. pneumoniae strains were identified using Enterosystem 18R kit following the manufacturer's instructions. The antimicrobial susceptibility test (AST) was performed using the Kirby-Bauer disk diffusion method. The screening of ESBL production was done using ESBL ChromAgar medium combined with the double-disk synergy test (DDT). Antimicrobial resistance genes were detected using polymerase chain methods. The data analysis was performed using Excel 2016 and IBM SPSS version 20. A total of 215 urine samples were collected and analyzed during the study period. A 31.62% (68/215) prevalence of Enterobacterales was detected with prevalence of 79.41% (54/68) and 14.70% (10/68) for Escherichia coli and Klebsiella pneumoniae respectively. The overall prevalence of ESBL-Enterobacterales was 64.70% (44/68). About 82% (36/44) of isolates were MDR and high resistance level was observed for amoxicillin + clavulanic acid and ceftazidime. The resistance genes detected were blaCTX-M,and blaTEM respectively. The findings of this study highlight the high burden of MDR and ESBL-E. coli and K. pneumoniae isolates from UTIs. The study emphasizes the necessity of routine screening and monitoring of antimicrobial resistance in healthcare facilities and community settings. It is therefore crucial to implement antimicrobial stewardship programs in the country and infection prevention and control (IPC) measures in hospital settings.

Antimicrobial activity of adipose-derived mesenchymal stromal cell secretome against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is still a growing concern in the field of antimicrobial resistance due to its resistance to conventional antibiotics and its association with high mortality rates. Mesenchymal stromal cells (MSCs) have been shown as a promising and attractive alternative treatment for bacterial infections, due to their antibacterial properties and potential to bypass traditional resistance mechanisms. This study aims to shed light on the antibacterial potential of adipose-derived mesenchymal stromal cell (AD-MSC) secretome against clinical isolates of Staphylococcus spp., including MRSA strains. Using the Kirby-Bauer disk diffusion method, broth microdilution assays, and colony-forming unit (CFU) counting, the antibacterial activity of AD-MSC secretome was assessed. These tests were first conducted on Staphylococcus (S.) aureus ATCC 25923, then on 73 clinical isolates including MRSA strains. Further molecular analysis was performed to identify resistant genes in MRSA isolates. The AD-MSC secretome demonstrated significant antibacterial activity against S. aureus ATCC with a 32mm inhibition zone. 96% of the collected staphylococcal clinical isolates showed susceptibility to the secretome with 87.5% inhibition observed in MRSA isolates, along with 100% in MSSA, MSSE, and MRSE strains. Molecular analysis revealed that MRSA strains resistant to the secretome harbored mecA, ermA, and ermB genes. Additionally, the mecA-negative MRSA strains remained susceptible to the secretome, suggesting alternative resistance mechanisms. These findings emphasize the ability of AD-MSCs secretome as a promising alternative for treating antibiotic-resistant infections, with potential applications in combating MRSA. However, further research is required to explore its clinical applications as a complementary or standalone therapy for resistant infections.

Antimicrobial resistance pattern and species distribution profile of aerobic bacteria causing sterile body fluid infection from a tertiary care hospital

Objectives: Body fluids such as pleural fluid, ascitic fluid, and cerebrospinal fluid are sterile but they can get infected by different microorganisms leading to life-threatening infections. We conducted this study to evaluate the distribution profile of various aerobic bacteria and their antimicrobial resistance pattern isolated from sterile body fluids from the patients attending a tertiary care hospital in North India. Materials and Methods: This hospital-based cross-sectional observational study was conducted in the Department of Microbiology of a tertiary care hospital. A total of 495 sterile body fluid samples were processed for species-level identification of aerobic bacteria by conventional methods following standard laboratory procedures. The antimicrobial susceptibility testing was performed by Kirby–Bauer disc diffusion method according to clinical and laboratory standards institute guidelines 2020. Results: Out of a total of 495 sterile body fluid samples, 48 were found positive on culture for bacterial pathogens. The predominant organisms isolated from sterile body fluids were Acinetobacter species (35%), followed by Klebsiella species (23%), Escherichia coli (13%), Pseudomonas species (12%), Staphylococcus aureus (13%), and Streptococcus species (4%). All of the Gram-negative isolates were 100% sensitive to Colistin followed by amikacin (67.50%) and gentamicin (60%). The Gram-positive isolates were 100% sensitive to vancomycin and linezolid followed by gentamicin (50%). Conclusion: Infections of sterile body fluids can lead to high morbidity and mortality. The knowledge of the bacteriological and antimicrobial resistance profile of bacteria causing sterile body fluid infections is vital in determining appropriate antimicrobial therapy.

A STUDY ON BACTERIOLOGICAL PROFILE OF SURGICAL SITE INFECTION AND THEIR ANTIMICROBIAL SUSCEPTIBILITY PATTERN AT A TERTIARY CARE HOSPITAL IN TIRUPATI

Objective: Surgical Site Infections (SSIs) are defined as infections apparent within 30days of an operative procedure and most often between the 5th and 10th postoperative days. It constitutes a major public health problem worldwide; It is one of the most common causes of nosocomial infection. They are responsible for increasing the treatment cost, length of hospital stays and significant morbidity and mortality. Despite the technical advances in infection control and surgical practices, SSI still continue to be a major problem, even in hospitals with most modern facilities. The present study conducted to isolate and identify microbes from pus samples collected from patients who were suspected for SSI and to determine their antimicrobial susceptibility profiles in a tertiary care hospital. Methods: This is a cross-sectional study conducted in the Department of Microbiology, Sri Venkateswara Medical College, Tirupati for a period of 6 mo. A total of 390 various clinical samples were collected and processed. Isolates were tested for antibiotic susceptibility by a Kirby-Bauer disk diffusion method. Results: Out of 390 pus/wound discharge samples processed, 132 (34%) samples were culture positive, among which 107 (81%) were Gram-negative bacilli and 25 (19%) were Gram-positive cocci. Male to female ratio was 2:1. Most common age group affected was>50yrs. Predominant isolates were Klebsiella pneumoniae (73.47%) followed by Pseudomonas aeruginosa (26.53%) and Staphylococcus aureus (17.4%). Gram-negative bacilli showed maximum susceptibility to Imipenam, Piperacillin-Tazobactam and Amikacin and Gram-positive cocci showed 100% to Linezolid, Vancomycin. Conclusion: SSI remains to be a significant challenge for the surgeon’s inspite of sterile surgical techniques and prophylactic use of antibiotics. Hospital infection control measures like hand hygiene, strict adherence to pre-operative measures, rational use of antibiotics and establishing active surveillance can reduce the prevalence of SSIs.

Prevalence and Risk Factors for Colonization with Carbapenem-Resistant Microorganisms in Patients Admitted to a Multidisciplinary Hospital

Relevance. In the last decade, there has been an increase in the isolation of antibiotic-resistant microorganisms in community settings. Colonization and asymptomatic carriage of extended-spectrum beta-lactamase and carbapenemase producers can be a precursor to the development of an infectious process and a significant factor in the pathogenesis of healthcare-associated infections. Understanding the risk factors for community-acquired colonization with antibiotic-resistant microorganisms is necessary for targeted screening and timely implementation of measures to prevent the spread of resistance in hospitals.The aim. To determine significant risk factors for colonization with antibiotic-resistant gram-negative microorganisms and carriage of carbapenem resistance genes in patients admitted to a multidisciplinary hospital.Materials & Methods. A prospective single-center crosssectional study was conducted at the Moscow Multidisciplinary Clinical Center «Kommunarka» from 15.09.2022 to 15.08.2023. The study included 733 patients aged 18 to 94 years. Biological samples were taken from the rectum, upper and lower respiratory tract. The obtained samples were examined by real-time polymerase chain reaction (PCR) with hybridization-fluorescent detection of amplification products to identify carbapenemase genes and by culture method to determine colonization with carbapenemresistant bacteria. Identification of isolated microorganisms was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and antibiotic susceptibility was determined by the Kirby-Bauer disk diffusion method on Mueller-Hinton agar. The results of susceptibility testing were interpreted based on EUCAST v12.0, v13.0, and v13.1 criteria.Results. Carriage of carbapenemase genes was detected in 12.6% of patients admitted to the hospital, while colonization with carbapenem-resistant bacteria was found in 2.7%. In the majority of patients (66.7%), the rectum was the only site of gene carriage. However, only 18.1% of these patients showed rectal colonization with carbapenem-resistant bacteria. This discrepancy is likely due to the higher sensitivity of molecular genetic methods compared to culture-based techniques. From a clinical perspective, the detection of nucleic acids by PCR can serve as an equivalent to pathogen detection in biological material. Multivariate analysis identified 5 independent predictors of colonization: cytostatic therapy, transfer from another hospital, need for vasopressor support, antibiotic use in the previous 3 months, and male gender.Conclusion. The identified risk factors allow for the identification of a highrisk patient cohort for targeted screening, enabling timely administration of appropriate antibiotic therapy and implementation of measures to prevent the spread of carbapenem resistance in the hospital.

Antimicrobial Residues in Poultry Litter: Assessing the Association of Antimicrobial Persistence with Resistant Escherichia coli Strains.

Objective: We set out to evaluate the persistence of sulfachloropyridazine, oxytetracycline, and enrofloxacin in broiler chicken litter following therapeutic oral treatment and its association with the isolation of Escherichia coli resistant to these antimicrobials. Methods: Forty broiler chickens were raised under controlled conditions and divided into three experimental groups, each treated with a different antimicrobial, in addition to an untreated/control group. Litter samples were collected post treatment, analyzed by UPLC-MS/MS, and processed for the isolation of E. coli. The antimicrobial susceptibility of E. coli was assessed using the Kirby-Bauer disk diffusion method. Results: Chemical analysis detected concentrations of antimicrobials throughout post treatment, reaching maxima of 42,910.14 μg kg-1, 92,712 μg kg-1, and 9567 μg kg-1 for sulfachloropyridazine, oxytetracycline plus 4-epi-oxytetracycline, and enrofloxacin plus ciprofloxacin, respectively. It was estimated that the concentrations of sulfachloropyridazine, oxytetracycline, and enrofloxacin would persist in broiler litter for 61, 244, and 514 days, respectively. A very strong association was observed between the presence of antimicrobial residues and the antimicrobial resistance of E. coli (p-value < 0.0001, and Cramer's coefficient of 0.47), and an independence between the level of residue concentration and susceptibility (p-value 0.5262). Conclusions: The persistence of antimicrobial residues contributes to the selection of resistant bacteria, regardless of persistent antimicrobial concentrations. These findings highlight the need for stricter regulations on poultry litter management, including residue thresholds and resistance monitoring, to minimize environmental and public health risks. Proper treatment of poultry litter is essential to ensure its sustainable and safe re-use in agricultural systems.

Clinical and molecular analysis of ESBL, carbapenemase, and colistin-resistant bacteria in UTI patients.

Uropathogens, particularly bacteria, can infect any part of the urinary tract and cause bacteriuria. Our study aimed to examine the antibiotic-resistant profile, associated risk factors, and phenotypic and genotypic features of ESBL, carbapenemase, and mcr resistance genes in multidrug-resistant bacteria. Samples were inoculated on culture media, identified using standard biochemical tests, and species confirmation was performed via 16S rRNA gene amplification. Furthermore, antibiotic susceptibilities were evaluated using the Kirby-Bauer disc diffusion method. The phenotypically confirmed resistant strains were further inspected for ESBL, carbapenemases, and mcr variants using PCR. Merely 57.24% (83/145) of the samples exhibited growth. Of these, 39.70% (33/83) were identified as Klebsiella pneumoniae, 27.70% (23/83) as Escherichia coli, 10.80% (9/83) as Pseudomonas aeruginosa, 9.60% (8/83) as Staphylococcus aureus, 7.20% (6/83) as Proteus mirabilis, and 4.80% (4/83) as Staphylococcus saprophyticus. Overall, 22.54% (16/71) of the gram-negative strains were confirmed molecularly to have resistant genes. The ESBL - producers accounted for 21.74% (5/23) of E. coli, 21.21% (7/33) of K. pneumoniae, and 22.22% (2/9) of P. aeruginosa. Likewise, carbapenemase-harboring strains included 6.06% (2/33) of K. pneumoniae, 4.35% (1/23) of E. coli, and 11.11% (1/9) of P. aeruginosa. Notably, 3.03% (1/33) of K. pneumoniae, 8.70% (2/23) of E. coli, and 11.11% (1/9) of P. aeruginosa strains tested positive for the mcr-1 gene. None of the Proteus strains showed any resistant genes. The most common variants were blaSHV-11 (non-ESBL) and blaCTX-M-15 (ESBL) accounted for 28.57% (4/14) each, blaTEM-116 accounted for 14.29% (2/14), blaSHV-1, blaSHV-75, blaTEM-1 and blaOXA-1 accounted for 7.14% (1/14) each of the ESBL. Similarly, the carbapenemase variants included blaOXA-48, blaNDM-1, blaVIM-1, and blaKPC-2, each accounting for 25.0% (1/4), while 37.50% (6/16) of the strains exhibited co-existence of different gene variants. Based on our findings, it can be concluded that females, especially those in middle age, were more infected. These pathogens exhibited a wide range of ESBL, carbapenemase, and mcr-1 variants. Imipenem was suggested as the preferred medication.

Antibiogram Profile of Patients Having Urinary Tract Infection Treated with Most Commonly Used Antibiotics

Background: Urinary tract infections (UTIs) are the most common infections in humans, primarily caused by bacteria, with Escherichia coli (E. coli) responsible for 75-90% of cases. The rise in bacterial resistance is largely due to inappropriate antibiotic use, posing significant public health concerns. This study investigated UTI prevalence and antibiotic resistance to inform optimized treatment guidelines. This study aimed to identify the bacterial pathogens causing UTIs and assess their antimicrobial sensitivity and resistance to commonly used antibiotics. Method: A descriptive cross-sectional study was conducted over six months at Khyber Teaching Hospital's Microbiology Department to assess the antibiogram profile of uropathogens from urine cultures. Urine samples were cultured on CLED media, and biochemical tests were used to identify the uropathogens. Antimicrobial susceptibility testing was performed on the isolates using the Kirby-Bauer disk diffusion method on Mueller Hinton Agar (MHA), following CLSI guidelines. A total of 384 patients' urine samples were collected through a convenient technique and processed as per standard guidelines. The collected data was analyzed using SPSS-22 and shown in tables. Results: Escherichia coli was the most common uropathogen, found in 48.17% (n=185) of cases, with a higher prevalence in females at about 48.4% (n=125). Fosfomycin was the most frequently prescribed antibiotic (31.5%) and showed the highest sensitivity (50.2%). Cefotaxime exhibited the highest resistance (38.45%), followed by Amoxicillin-clavulanic acid (34.8%). Conclusion: Escherichia coli remains the dominant pathogen, with Fosfomycin proving generally effective, while resistance to cefotaxime is notable. These reports show the importance of antibiotic use responsibly. By selecting appropriate antibiotics, we can minimize the resistance rate of uropathogens.

Antibiotic Resistance Profile of Enterovirulent E. coli Isolates Harboring Broad-Spectrum Beta-Lactamase Genes in Cancer Patients at the Laquintinie Hospital in Douala, Littoral Region, Cameroon.

Cases of antibiotic-resistant Escherichia coli (E. coli) infections are becoming increasingly frequent and represent a major threat to our ability to treat cancer patients. The emergence of antimicrobial resistance threatens the treatment of E. coli infections. In this study, the antimicrobial profiles, virulent genes, and the frequency of extended-spectrum beta-lactamase (ESBL) gene carriage in fecal E. coli isolates from cancer patients at the Laquintinie Hospital in Douala (Cameroon) were determined. 507 participants were recruited from October 2021 to March 2023, of whom 307 (60.55%) had cancer and 200 (39.45%) did not. Two hundred and two E. coli were isolated from fecal samples of one hundred and fifteen cancer patients and 47 (87) noncancer patients using EMB LEVINE agar. The antimicrobial resistance profile of the isolates was determined using the Kirby-Bauer disk diffusion method. Virulence and resistance genes were detected by simplex polymerase chain reaction (PCR). E. coli showed significant rates of resistance to amoxicillin, cefotaxime, ceftazidime, piperacillin, tetracycline, and ciprofloxacin in cancer patients compared to noncancer patients. The rate of multidrug resistance (MDR) was significantly (p < 0.05) higher in cancer patients than in noncancer patients. Fifty-five enterovirulent E. coli were identified, of which 24 (43.63%) were EPEC, 13 (23.63%) were EAEC, 6 (10.90%) were ETEC, 10 (18.18%) were STEC, and 2 (3.63%) were EIEC. The frequency of beta-lactamase genes in the 55 ESBL-producing enterovirulent E. coli isolates was determined, and 94.54% harbored at least one ESBL gene, distributed as follows: 80.00% for bla TEM, 67.27% for bla CTX-M, 24.63 for bla OXA, and 36.36% for bla SHV genes. Several associations were observed between virulence factors, resistance genes, and the antimicrobial resistance phenotype. This study revealed the real existence of fecal carriage of ESBL-producing enterovirulent E. coli isolates from cancer patients with a high rate of MDR in the latter.

Genotypic detection of metallo-Beta-Lactamases among multidrug resistant Klebsiella pneumoniae isolated from urine samples of UTI patients

Metallo-beta-lactamases producing bacteria are of public health concern, owning to the fact that bacteria that harbour genes for their production are notably resistant to several antibiotics. This study was carried out to genotypically investigate the prevalence of MBL-production in multidrug resistant K. pneumoniae isolated from urine samples of UTI patients attending a tertiary teaching hospital in Awka, Anambra State, Nigeria. Two hundred (200) mid-stream urine samples were collected from UTI patients, and were analyzed using standard microbiological procedures. Antibiotic susceptibility testing (AST) of the isolates was carried out using Kirby-Bauer disc diffusion method and combination disc test was employed to phenotypically screen the isolates for MBL production. The genotypic screening was performed by Polymerase chain reaction (PCR), using specific primers. Fifty-one (51) K. pneumoniae isolates were recovered from the urine samples. AST revealed that the isolates exhibited high resistance to Amoxicllin-clavulanic acid (100%), Ampiclox (98.04%), Imipenem (98.04%), Cefotaxime (96.08%), Cefuroxime (96.08%), Nitrofurantoin (70.59%), and were relatively susceptible to Ofloxacin (54.91%), Gentamycin (50.98%) and Levofloxacin (47.06%). A 79.02% of the K. pneumoniae isolates showed resistance to more than two classes of antibiotics, thus termed multidrug resistance strains. Of the 38 (41.76%) isolates of K. pneumoniae that were resistant to imipenem, 19 (20.88%) were confirmed as MBL-producers phenotypically, while 19 (20.88%) were non-MBL producers. Genotypically, blaVIM (21.98%) was the most detected MBL gene, followed by blaOXA-48 (18.68%) and blaIMP (15.38%). This study revealed the prevalence of multidrug resistant and MBLs producing K. pneumoniae in urine samples of the selected UTI patients.

Antimicrobial resistance, virulence gene profiling, and genetic diversity of multidrug-resistant Pseudomonas aeruginosa isolates in Mazandaran, Iran

BackgroundPseudomonas aeruginosa is a major cause of healthcare-associated infections (HAIs), particularly in immunocompromised patients, leading to high morbidity and mortality rates. This study aimed to investigate the antimicrobial resistance patterns, virulence gene profiles, and genetic diversity among P. aeruginosa isolates from hospitalized patients in Mazandaran, Iran.MethodsFrom September 2021 to April 2022, 82 non-duplicate P. aeruginosa isolates were collected from diverse clinical sources. Identification was confirmed using API 20 NE (bioMérieux, Marcy l’Etoile, France). Antimicrobial susceptibility testing was conducted using the Kirby-Bauer disk diffusion method according to CLSI guidelines to assess resistance to a range of antibiotics. The virulence profile (exoT, exoY, exoU, toxA, plcH, plcN, algD, aprA, lasB and exoS) of each P. aeruginosa isolate was determined by PCR. The genetic diversity among the strains was evaluated using the random amplification of polymorphic DNA (RAPD) technique. Clustering was based on a Dice similarity coefficient of ≥ 85%.ResultsOf the 82 total strains, P. aeruginosa exhibited the highest and lowest resistance toward ticarcillin-clavulanate (98.78%) and colistin (0%), respectively. Moreover, 100% of the P. aeruginosa isolates were MDR. The following prevalence of virulence factor genes was observed: aprA, lasB, algD, toxA, plcH, exoY, and exoT in 100% of isolates. The plcN, exoS, and exoU were identified 98.78%, 67.07%, and 45.12%, respectively. The RAPD patterns obtained with primers 272 and 208 had respectively 2–19 and 6–17 bands. According to the Dice similarity coefficient of higher than 85%, 56 and 39 clusters were recognized.ConclusionThe high rate of multidrug resistance combined with the widespread presence of virulence genes in P. aeruginosa isolates highlights the potential for increased infection severity, morbidity, and mortality in hospitalized patients. The substantial genetic diversity observed among isolates suggests that P. aeruginosa in this region may rapidly evolve, necessitating ongoing surveillance and more targeted antimicrobial strategies.Clinical trial numberNot applicable.

Antimicrobial resistance, virulence profiling, and drug repurposing analysis of Staphylococcus aureus from camel mastitis.

Camel mastitis especially caused by Staphylococcus aureus (S. aureus), is a major risk to animal health and milk production. The current investigation evaluated the antibiotic susceptibility and virulence factors of S. aureus isolates from subclinical mastitis in camels. A total of 384 milk samples were collected and submitted to isolate S. aureus. The S. aureus isolates exhibiting resistance to Penicillin and Cefoxitin disc on Kirby-Bauer disc diffusion method were considered as β-lactam resistant S. aureus (BRSA) and methicillin-resistant S. aureus (MRSA) which were further confirmed by PCR targeting blaZ and mecA genes, respectively. The results showed that S. aureus was found in 57.06% of subclinical (SCM) positive camel milk samples. A high molecular prevalence of BRSA and MRSA were found to be 48.51% and 46.53% respectively depicting that treating these infections is challenging due to their high resistance levels. The phylogenetic analysis revealed a significant resemblance of the study isolates with each other and with already reported sequences from different countries which shows the potential for the spread of pathogen. Virulence profiling of antibiotic resistance strains showed the presence of virulence markers (nuc and coag genes), intercellular adhesion genes (icaA, icaD), Panton-Valentine leukocidin (pvl) gene, and enterotoxin-producing genes including sea, seb, sec, and sed. In-vitro antibiotic susceptibility testing revealed that the most resistant antibiotic group was penicillin followed by aminoglycosides and cephalosporins. Drug repurposing analysis of different non-antibiotics for combination therapies with resistant antibiotics was done to combat the S. aureus isolates harboring the mecA and blaZ genes. The results revealed the synergistic effect of amoxicillin, sulfamethoxazole, gentamicin, and doxycycline with ketoprofen, amikacin with flunixin meglumine, and gentamicin with N-acetylcysteine (NAC) against study isolates. The current investigation provides the status of antibiotic-resistant strains and virulence factors of S. aureus in the udder of dromedary camels. The combinational therapy of resistant antibiotics with non-antibiotics provides a potential therapeutic option for the treatment of resistant strains.

Antimicrobial resistance and molecular characterization of Escherichia coli and Staphylococcus aureus isolated from common fast foods in Gazipur city, Bangladesh

The increased trend in fast food consumption in Bangladesh has raised massive public health concerns about bacterial contamination and its resistance pattern to available antibiotics. This study aims to isolate, identify, and molecular characterization of Escherichia coli and Staphylococcus aureus from fast food samples sold within Gazipur City, Bangladesh, determine their antibiotic resistance profiles and virulence gene detection. A total of 120 samples including fuchka, burgers, sandwiches, and chicken roll were collected from different street vendors and restaurants in Gazipur City. Conventional microbiological methods were employed for the isolation and identification of anticipated isolates, while PCR techniques utilizing nuc and malB genes were implemented for molecular detection. Antibiotic sensitivity patterns were assessed using the Kirby-Bauer disc diffusion method and interpreted in accordance with CLSI guidelines. Out of 120 samples, 26 (21.66%) S. aureus and 22 (18.33%) E. coli were phenotypically detected by cultural and biochemical tests, whereas 12 (46.15%) nuc gene of S. aureus and 10 (45.45%) malB gene of E. coli were genotypically detected. The 6 nuc gene of S. aureus isolates exhibited resistance to cefoxitin, oxacillin, and penicillin (100%), and frequently moderate resistance to clindamycin (50%), whereas 83.33% were sensitive to doxycycline, gentamicin, azithromycin, and levofloxacin, respectively. Similarly, all E. coli isolates showed 100% resistance against erythromycin, ampicillin, and 80% resistance elicited against ceftazidime and tetracycline, respectively. Potentially significant for public health, this study found that fast food offered in restaurants was tainted with harmful S. aureus and E. coli isolates. The detection of MDR bacteria in fast food poses immense public health risks, and there is a dire need to improve food safety practices.

Presence and characterisation of extended spectrum beta-lactamase producing Gram-negative bacteria obtained from water in selected storage tanks

Objective: To detect the presence of extended-spectrum beta-lactamase-producing Gram-negative bacteria in water from selected storage tanks in Ogun State, Nigeria. Methods: MacConkey agar supplemented with 6 µg/mL of cefotaxime was used to isolate bacteria. Pure isolates were identified through PCR amplification. The susceptibility patterns of the isolates to ceftazidime (30 µg/mL), amoxicillin/clavulanate (30 µg/mL), tetracycline (30 µg/mL), cefotaxime (30 µg/mL), cefpodoxime (10 µg/mL), and ciprofloxacin (5 µg/mL) were evaluated using the Kirby-Bauer disc diffusion method, while the identification of beta-lactamase production was performed using the double disc synergy test. Results: A total of 19 isolates belonging to four genera (Citrobacter, Pseudomonas, Escherichia, and Serratia) were obtained from the ten water samples. Escherichia coli and Citrobacter spp. had the highest presence (30.0%). The antibiotic with highest resistance was observed to be cefpodoxime (100%) followed by amoxicillin/clavulanate (89.5%) and cefotaxime (89.5%), the least was noted with tetracycline (31.6%). Additionally, 10 (52.6%) out of the 19 isolates showed beta-lactamase-producing phenotypic properties with high resistance to cefpodoxime (100%), amoxicillin/clavulanate (100%) and ceftazidime (90.0%). Additionally, this study showed the link between bacterial strains identified by 16S rRNA and related human diseases, highlighting the importance of genetic identification in managing infections. Conclusions: This study highlights the prevalence of beta-lactam-resistant bacteria, emphasizing the urgent need for proactive measures to address this issue.

Assessment of Microbial Contamination and Antibiotic Resistance Profiles of Bacteria on Nigerian Currency Notes: Implications for Public Health and Antimicrobial Resistance

Background: Many microbes have been associated with the contamination of Naira notes, and most of these microbes have shown high resistance to antimicrobials, with different resistance profiles including multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR). Therefore, the aim of this study was to investigate the microbial contamination and antibiotic resistance profiles of isolated microorganisms on Nigerian currency notes, emphasizing their public health implications. Methods: A total of 112 currency notes, spanning all eight denominations, were collected from rural (Oyan) and urban (Osogbo) regions in Osun State, Nigeria. Microbial isolation and identification were performed using standard culture techniques, while antibiotic susceptibility was assessed via the Kirby-Bauer disc diffusion method. Data were analyzed using SPSS. Results: Microbial analysis revealed high contamination rates, with Klebsiella sp (35.7% rural, 23.2% urban) and Staphylococcus aureus (28.6% rural, 26.8% urban) being the most prevalent bacterial isolates. Aspergillus sp was the dominant fungal contaminant, particularly in rural areas. Polymer-based notes exhibited lower contamination compared to paper-based notes. Antibiotic susceptibility tests highlighted alarming multidrug resistance (MDR), with Staphylococcus aureus showing high resistance to Penicillins and Cephalosporins. Pseudomonas aeruginosa displayed extensive drug resistance (XDR) to multiple antibiotic classes, leaving limited treatment options. Conclusion: Nigerian currency notes are significant reservoirs of microbial contamination and multidrug-resistant pathogens, posing severe public health risks. The study underscores the need for improved hygiene practices, public awareness campaigns, and a transition to polymer-based notes. Strengthened antibiotic stewardship programs and regulatory measures are essential to combat rising antimicrobial resistance and prevent pathogen dissemination through currency handling.

Antimicrobial resistance profile of bacteria from hospital wastewater at two specialized hospitals in Bahir Dar city, Ethiopia

BackgroundThe high levels of antimicrobial consumption in hospitals contribute to the occurrence of antimicrobial resistant bacteria. Antimicrobial resistant bacteria and sub-lethal concentrations of antimicrobial metabolites can end up in hospital wastewater which can spread to the environment and to the community. However, information on the resistance profile of bacteria isolated from environments is not well studied. Thus, the main aim of this study was to determine the antibiotic resistance profile of bacteria from hospital wastewater in Bahir Dar City, Northwest Ethiopia.MethodA total of 70 hospital wastewater samples were collected from two comprehensive specialized hospitals using a grab-sampling technique. Bacteria were identified using colony morphology, Gram staining, and biochemical tests. The drug susceptibility test was performed using the Kirby-Bauer disc diffusion method on Muller-Hinton agar.ResultThe most dominant bacterial isolates from hospital wastewater were Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Citrobacter spp., Acinetobacter spp., Enterobacter spp., Klebsiella pneumoniae (K. pneumoniae), and Pseudomonas aeruginosa (P. aeruginosa). All K. pneumoniae and 52.4% (11/21) E. coli were resistant to ceftazidime (third-generation cephalosporin), while Citrobacter spp., Acinetobacter spp., and Enterobacter spp., were susceptible to ceftazidime. Likewise, S. aureus revealed 64% (16/25) resistance to erythromycin. Overall, 22.2% of bacterial isolates were multidrug resistant bacteria to the commonly prescribed antimicrobials.ConclusionHospital waste waters contain high prevalence of multiple drug-resistant bacteria, particularly the third-generation cephalosporin resistant K. pneumoniae and E. coli would be a big concern. Infection prevention and control practices with proper treatment of hospital wastewater before discharging should be in practice to contain the spread of drug-resistant bacteria from hospital to external environment.

Investigation of integron classes 1, 2, and 3 among multi-drug resistant Staphylococcus aureus isolates in Iran: a multi-center study

BackgroundRising methicillin-resistant Staphylococcus aureus (MRSA) poses a global health threat, contributing to serious infections with high mortality rates. Integrons are recognized as significant genetic elements in disseminating multidrug-resistant (MDR) strains. This study focuses on assessing the prevalence of integron classes 1, 2, and 3 in S. aureus strains from four major cities in Iran.MethodsThis cross-sectional study analyzed 183 S. aureus isolates from Shiraz, Tehran, Isfahan, and Yazd in Iran. The isolates were identified using specific biochemical and molecullar tests. The Kirby-Bauer disc diffusion method and microbroth dilution method were employed to determine the susceptibility of the isolates to relevant antibiotics and vancomycin, respectively. The macrolide-lincosamide-streptogramin B (MLSB) resistance phenotype was also evaluated using the D-test. All isolates were sought for presence of the intI1, intI2, and intI3 genes.ResultsAmong 183 S. aureus isolates, high resistance rates were noted: 86.3% for erythromycin, 66.1% for ciprofloxacin, and 61.7% for clindamycin, while all isolates were susceptible to linezolid and vancomycin. Of the 183 isolates, 59.6% were identified as MRSA and 78.1% as MDR. According to the D-test results, 112/183 (61.2%), 29/183 (15.8%), 25/183 (13.7%), and 17/183 (9.7%) of S. aureus isolates showed constitutive resistance-MLSB, inducible resistance-MLSB, sensitive, and resistance to macrolide-streptogramin B (MS) phenotypes, respectively. The intI1 gene was found in 14 out of 183 S. aureus isolates (7.6%), while none were positive for the intI2 or intI3 genes. Notably, 11/14 (78.5%) and 13/14 (92.8%) intI1-positive isolates were MRSA and MDR, respectively.ConclusionsThe distribution of MRSA and MDR S. aureus isolates in Iran seems concerning. Although the prevalence of intI1 was not as high as in prior studies, almost all S. aureus harbored the intI1 gene were MRSA and MDR.

Antibiotic Susceptibility of Zoonotic Bacteria Isolated From Oral Cavities of Indigenous Dogs From Semi-Urban Areas in Uganda.

Dog bites are a source of zoonotic infections to humans, such as pasteurellosis and meningitis. Zoonotic bacterial identification and their antibiotic susceptibility assessment are key towards the successful management of such infections. This study isolated and identified zoonotic bacterial species from the oral cavities of indigenous dogs and also determined their antibiotic susceptibility profile. Oral swab samples collected from 54 indigenous dogs (domestic [36] and stray [18]) were cultured on agar media, and then on selective-differential media. The colony morphology and conventional biochemical tests were used to identify the bacterial isolates. Antibiotic susceptibility was evaluated using the Kirby-Bauer disk diffusion method. A total of 232 bacterial isolates were obtained, from which 29 bacteria species (18 Gram-negative and 11 Gram-positive) belonging to 19 genera and 13 families were identified. Aerobic and anaerobic bacteria species constituted 69% and 31%, respectively. The most prevalent bacteria species was Staphylococcus aureus (10.8%) followed by Escherichia coli (9.5%), while Yersinia enterocolitica (0.4%) was the least common. Most bacteria species belonged to family Enterobacteriaceae (11) followed by Vibrionaceae (04). All the sampled dogs had a number of multi-drug-resistant superbugs in their oral cavities. However, all the tested bacterial isolates were only susceptible to imipenem and chloramphenicol. All the identified bacteria species were resistant to metronidazole, amoxicillin-clavulanic acid and ceftazidime. Therefore, antibiotics such as imipenem and chloramphenicol could be of better choice for managing dog bite infections compared to the antibiotics recommended by Uganda Clinical Guidelines, such as metronidazole and amoxicillin-clavulanic acid.

Green synthesis of silver nanoparticles using Acroptilon repens aqueous extract and their antibacterial efficacy against multidrug-resistant Acinetobacter baumannii.

Acinetobacter baumannii is a critical pathogen associated with hospital-acquired infections, particularly in burn and intensive care unit (ICU) patients, and is notorious for its high level of antibiotic resistance. This study aims to evaluate the antibacterial potential of silver nanoparticles (AgNPs) synthesized using Acroptilon repens extract as a promising alternative treatment for combating multidrug-resistant A. baumannii. Twelve clinical isolates of A. baumannii were identified through biochemical testing. Antibiotic susceptibility testing using the Kirby-Bauer disk diffusion method revealed universal resistance to ceftazidime, amikacin, imipenem, gentamicin, ciprofloxacin, and piperacillin-tazobactam, while all isolates remained sensitive to colistin (p ≤ 0.05). AgNPs were synthesized using A. repens extract and characterized through transmission electron microscopy (TEM), scanning electron microscopy (SEM), particle size analysis (PSA), UV-Vis spectroscopy, X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). TEM analysis showed that the AgNPs had a spherical morphology with an average particle size of approximately 30nm, while SEM confirmed their spherical shape and size distribution, ranging from 10 to 130nm, with a mean size of 38.89nm. UV-Vis spectroscopy confirmed the successful formation of AgNPs, indicated by a distinct broad absorption peak between 400 and 480nm. XRD analysis validated the crystalline nature of the nanoparticles, with characteristic peaks at 2θ values of 38.21°, 46.28°, 64.57°, and 77.49°, corresponding to the (111), (200), (220), and (311) planes of face-centered cubic (fcc) silver. Antibacterial activity was evaluated by determining the minimum inhibitory concentration (MIC), which ranged from 50 to 400µg/mL. The highest inhibitory activity was observed at 400µg/mL. Gene expression analysis using quantitative real-time PCR (qRT-PCR) demonstrated downregulation of the oprD and carO porin genes following AgNP treatment. However, these reductions were not statistically significant (p = 0.302 and p = 0.198, respectively). AgNPs synthesized from A. repens demonstrated strong antibacterial activity against multidrug-resistant A. baumannii. While downregulation of porin genes was observed, further investigation is required to elucidate the underlying mechanisms of action and assess their potential clinical applications. These findings support the potential of AgNPs as an alternative therapeutic strategy for addressing A. baumannii infections resistant to conventional antibiotics.

In Vitro Evaluation of the Antifungal Properties of Bixa orellana L. Essential Oil from the Ecuadorian Amazon Against Candida albicans (ATCC 10231).

Essential oils are investigated due to their biological activity, and the Amazon rainforest, with its rich biodiversity, is a promising source of therapeutic compounds. The aim of this study was to evaluate the essential oil from the leaves of Bixa orellana as an antifungal agent, thus contributing to the search for alternatives that can address the growing resistance to conventional antifungals. B. orellana leaves were collected in the Ecuadorian Amazon and their essential oil was obtained by steam distillation. Their chemical composition was analysed by Gas Chromatography-Mass Spectrometry (GC-MS) and their antifungal activity against Candida albicans was evaluated using the Kirby-Bauer disc diffusion method (ATCC 10231), with nystatin as a positive control. GC-MS analysis revealed the presence of 60 compounds, the main ones being dihydroedulan (27.5%), β-caryophyllene (10.3%), nerolidol (7.21%), trans-β-bergamotene (5.73%), α-santalene (4.94%) and trans-α-bergamotene (4.26%). The essential oil showed moderate antifungal activity against C. albicans, producing an inhibition halo of 13 mm in diameter, which is 48% of the inhibition observed with nystatin (27 mm). The presence of sesquiterpenes, such as β-caryophyllene, known for its membrane-disrupting properties, probably contributes to the observed antifungal effects. The study highlights the potential of B. orellana essential oil as a natural antifungal agent; however, further research is required to evaluate its efficacy against a wider range of pathogenic fungi, its possible synergistic effects with conventional antifungals and its safety and efficacy in vivo.