Kirby-Bauer Disc Diffusion Method Research Articles

Enhancing antimicrobial management: A 5–year retrospective analysis of urinary pathogen susceptibility at a tertiary care centre from January 2018 to December 2022

Objective: The study aims to collect data on prevalence and antibiotic susceptibility patterns of uropathogens in a hospital in India, and to analyze any changes that have occurred over the past 5 years. Methods: This retrospective study was conducted over 5 years at Lady Hardinge Medical College & Associated Hospitals, New Delhi. Urine samples from patients who attended outpatient department or were admitted with diagnosis of urinary tract infection (UTI) were included in this study. Samples were cultured and tested to identify bacteria and determine antibiotic susceptibility using the Kirby-Bauer disc diffusion method. Results: A total of number of 151395 urine specimens were collected from January 2018 to December 2022. The prevalence of UTI was 7.5% (11372/151395) with the majority of patients being aged above 40 years (19.3%). The prevalence was higher in females (12.7%) as compared to males (3.2%). Escherichia (E.) coli was the predominant pathogen, accounting for 59.8% of cases, followed by Klebsiella spp. at 18.9%, and Enterococcus spp. at 8.3%. Gram-negative bacteria accounted for 89.5% of the isolates and exhibited good susceptibility to aminoglycosides and piperacillin-tazobactam, but showed resistance to fluoroquinolones. Methicillin-resistant Staphylococcus aureus (MRSA) was present in 35% of Staphylococcus (S.) aureus isolates with high susceptibility to glycopeptides and nitrofurantoin. Conclusions: The data suggest the need for careful selection of empirical therapy due to increasing resistance patterns. The stringent use of antimicrobial agents is pivotal to the control of antimicrobial resistance. Antibiotic susceptibility data contributes to tailoring the antibiotic stewardship programs to local needs.

Prevalence and Antimicrobial Susceptibility Patterns of Wound and Pus Bacterial Pathogens at a Tertiary Care Hospital in Central Riyadh, Saudi Arabia

The long history and extensive use of antibiotics have caused resistant bacterial pathogens to emerge, increasing mortality and morbidity. The current study was designed to see the prevalence of aerobic bacterial isolates with their antimicrobial resistance pattern from out- and inpatients requested for wound or pus culture. Retrospective study conducted at a tertiary care hospital in central Riyadh from January 2023 to December 2023. Samples were collected and inoculated onto the appropriate media following standard guidelines. Bacterial pathogens were identified by the Vitek2 compact system. Antimicrobial susceptibility was tested using the Kirby–Bauer disk diffusion method as well as by MIC determination through the Vitek2 compact. A total of 1186 subjects were included in the study with a bacterial isolation rate of 691 (58.3%). Out of these, 155 positive cultures had incomplete information or anaerobic or fungal growth and were excluded from the study. With a slight female predominance (54.9%), the majority of subjects (72.2%) were outpatients, and over half of the isolates (55.2%) were Gram-positive. The most common isolate was Staphylococcus spp. (44.4%), followed by E. coli (13.6%) and P. aeruginosa (12.9%). The highest resistance was reported against penicillin followed by fusidic acid against Gram-positive bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in 40.5% of Staphylococcus aureus (S. aureus) isolates. Amikacin was the most susceptible antibiotic against all Gram-negative isolates. MDR Gram-negative bacteria accounted for 51.9% of wound infection isolates (95% CI: 45.95 to 58.33) while 6.3% (95% CI: 4.39 to 8.86) were XDR (nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories). A high prevalence of bacterial isolates, with S. aureus as the predominant pathogen, showed high rates of multidrug resistance. This highlights the importance of monitoring antibiotic choices for prophylaxis and treatment in the study area.

Antibiotic resistant bacteria in goat meat and hygienic practices among retail stores in Nashville, Tennessee

This study explores into the levels of coliform contamination, prevalence of antibiotic-resistant bacteria, and the hygienic practices in goat meat retail stores. Goat meat from 10 retail stores was analyzed for E. coli, Salmonella, and S. aureus using serological and PCR methods. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Data on hygienic practices were collected through a structured observational questionnaire. Pearson’s correlation analysis was also employed to establish the relationship between hygienic practices and coliform loads. The average coliform loads on goat meat ranged between 0.88–5.04 log10 cfu/g. Our results revealed that 52% of examined goat meat was deemed unacceptable (>3.30 log10 CFU/g). The overall level of good meat handling practices among meat handlers in our study was 45.75%. Further, the study establishes a significant correlation between the level of food safety practices and coliform load. Hence, stores with higher hygienic practice scores exhibited lower coliform loads. The prevalence of S. aureus (44%) in goat meat was significantly higher (p < 0.05) as compared to E. coli (29%), and Salmonella spp. (20%). E. coli isolates displayed the highest resistance to penicillin (31.2%), Salmonella spp. to oxytetracycline (13.9%), and S. aureus to ampicillin (29.0%). Resistance was observed across selected antibiotic classes, particularly in beta-lactams and tetracyclines, with penicillin (78.5%) and oxytetracycline (64.5%) exhibiting notable resistance. Cephalosporin resistance was noted, with 48.4 and 33.3% of isolates showing resistance to cephalothin and cefpodoxime, respectively. Bacterial isolates also demonstrated resistance to phenicol antibiotics, including chloramphenicol (9.7%) and florfenicol (16.1%), respectively. Approximately 44.1% of bacterial isolates displayed multidrug resistance and MAR index ranged from 0.25 to 0.75. The study’s findings reveal heightened levels of coliform contamination, the presence of pathogenic and multidrug-resistant bacteria in goat meat, and suboptimal meat handling practices in retail stores. The significance of improving food safety practices in retail settings is emphasized to ensure the safety of goat meat, a matter of increasing importance due to its growing demand globally.

Vancomycin Resistant Enterococci and Trend of Antimicrobial Susceptibility in Urine Cultures

Background: Enterococci are emerging nosocomial pathogen showing resistance to broad spectrum antibiotics. As reported by the center for disease control and prevention, enterococci (13.9%) are the second leading cause of urinary tract infection, after Escherichia coli. After the first report of vancomycin-resistant enterococci in England (1988), India reported its first vancomycin resistant enterococci isolate from New Delhi (1999). The prevalence of vancomycin resistant enterococci ranges from 1-9%, in India. To evaluate the prevalence of vancomycin resistant enterococci among urinary isolates and to check their antimicrobial resistance pattern. Methods: A retrospective observational study conducted at a tertiary care hospital. Data were analysed from November, 2017 to October, 2018. A total of 12,129 urine samples were received and subjected to culture on HiCrome UTI agar (Hi-Media laboratories, Mumbai) and incubated at 37 °C for a period of 18-24 hours. Antimicrobial susceptibility was performed using Kirby–Bauer disc diffusion method. Identification was done on the basis of colony colour and species identification was done by using biochemical test as per standard laboratory protocol. In one case automated siemens microscan walkaway identification system was used for confirmation. Results: Enterococci were isolated in 4.06% from urine cultures out of which 7.52% were vancomycin resistant. Most of the vancomycin resistant enterococci isolate (86.49%) were multi drug resistant. Conclusion: In vancomycin resistant enterococci related urinary tract infection, nitrofurantoin can be used as an appropriate first choice in uncomplicated cases and linezolid should be reserved for serious and complicated urinary tract infections.

Antimicrobial resistance profiles of and associated risk factors for Pseudomonas aeruginosa nosocomial infection among patients at two tertiary healthcare facilities in Lusaka and Copperbelt Provinces, Zambia.

Antimicrobial resistance (AMR) of pathogens such as Pseudomonas aeruginosa is among the top 10 threats to global health. However, clinical and molecular data are scarce in Zambia. We, therefore, evaluated the AMR profiles of P. aeruginosa nosocomial infections (NIs). A year-long hospital-based cross-sectional study was conducted at two large tertiary-level hospitals in Zambia. Patients with current or previous hospital contact were screened for NIs. The current study focused on patients diagnosed with P. aeruginosa NIs. Clinical specimens were collected for bacteriological culture, and PCR amplification of 16S rRNA gene fragments was performed on pure isolates. Hospital or NIs were defined as infections that arise during hospitalization, occurring at least 48 h after admission. The Kirby-Bauer's disk diffusion method was used to evaluate antibiotic resistance patterns. The association between AMR and risk factors was analysed using the χ2 test. Eight hundred and forty-one patients were screened, and clinical specimens were collected and analysed. Of them, 116 (13.7%) were diagnosed with P. aeruginosa NIs. The participants' ages ranged from 15 to 98 years, with a mean of 51 (SD ± 18). Catheter-associated urinary tract infections (57%) were the most common, followed by pressure sores (38.7%). P. aeruginosa isolates were primarily susceptible to amikacin, which had the highest resistance to FEP. We observed a high prevalence of multidrug resistance (73.6%). The AMR was associated with carbapenem-hydrolysing β-lactamase gene blaOXA-51 and surgical care. This study has demonstrated that multidrug-resistant P. aeruginosa is prevalent in hospitals in Zambia's Lusaka and Ndola districts and possibly countrywide.

Pattern Of Antibiotic Resistance In Urinary Tract Infections: Insights From A Tertiary Care Hospital In Bangladesh

Background: Urinary tract infections (UTIs) are one of the most common bacterial infections, with increasing rates of antibiotic resistance complicating treatment. This study aimed to assess the prevalence and antibiotic resistance patterns of uropathogens in patients with UTIs at a tertiary care hospital in Bangladesh. Methods: A cross-sectional, retrospective study was conducted from June, 2023 to July, 2024 involving 60 UTI patients. Clinical and microbiological data, including urine cultures and antibiotic susceptibility tests, were collected. Antibiotic susceptibility testing was performed using the Kirby-Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Data were analyzed using SPSS version 26.0. Results: Escherichia coli was the most frequently isolated pathogen (50.0%), followed by Klebsiella spp. (20.0%). Both pathogens exhibited high resistance to ciprofloxacin (66.7%) and amoxicillin (83.3%) (p < 0.05). Pseudomonas spp. showed 66.7% resistance to ceftriaxone, and Proteus spp. exhibited 75.0% resistance to nitrofurantoin. However, E. coli and Klebsiella spp. demonstrated higher susceptibility to nitrofurantoin and gentamicin, with 50.0% and 66.7% susceptibility, respectively. Conclusion: The findings indicate a high prevalence of antibiotic-resistant uropathogens, particularly E. coli and Klebsiella spp., in the study population. Nitrofurantoin and gentamicin remain effective treatment options. These results highlight the urgent need for updated empirical treatment protocols and regular monitoring of resistance patterns to guide UTI management in Bangladesh.

Whole Genome Sequencing (WGS) Analysis of Antimicrobial Resistance (AMR) Milk and Dairy-Derived Pathogens from Anand, Gujarat, India

This study aimed to evaluate the antimicrobial resistance (AMR) patterns and genomic characteristics of Enterococcus faecalis, Enterococcus faecium, and Staphylococcus aureus strains isolated from dairy products, including buttermilk, curd, ice cream, and sweets, in the Anand region of Gujarat, India. A total of 205 isolates were analyzed, with the highest contamination levels found in buttermilk and curd. The bacterial isolates were identified using biochemical tests and advanced Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry. Antimicrobial susceptibility testing (AST) was performed using the Kirby-Bauer disk diffusion method, following CLSI guidelines, focusing on common antibiotics used for treating dairy-related bacterial infections. Resistance profiles were analyzed using WHONET software.s The findings revealed significant multidrug resistance (MDR), particularly among E. faecium and E. faecalis, with over 95% resistance to key antibiotics, including linezolid, ciprofloxacin, cefpodoxime, and carbapenems. Many strains were classified as MDR, XDR, and PDR. Staphylococcus aureus also exhibited substantial resistance to penicillin and enrofloxacin. whole-genome sequencing (WGS) and phylogenetic analysis to identify AMR determinants and conduct nucleotide sequence alignment. The study identified several antibiotic resistance genes, including LiaF, which regulates the expression of LiaR and LiaS genes. WGS revealed that genes such as GdpD, MprF, and PgsA encode intrinsic resistance determinants, contributing to antibiotic resistance. Additional AMR mechanisms were identified, including ABC transporter efflux pumps and the regulation of resistance genes by LiaR and LiaS. Phylogenetic analysis indicates a close relationship between Enterococcus faecium 640 1352.18624 and Enterococcus durans FB129-CNAB-4 883162.3.

Detection of antibiogram pattern and prevalence of blaNDM and blaVIM genes among carbapenem resistant Eschericia coli isolates in a tertiary care hospital

Background: Clinical significance of Eschericia coli is due to its capacity to develop resistance against many antibiotics specially carbapenem by producing carbapenemase which limits treatment options. blaNDM and blaVIM genes are responsible for this multi-drug-resistance. This is an alarming condition for society as well as clinician because they are very difficult to treat due to limited options of antibiotics and its high virulence. Aims and Objectives: The study was conducted to detect antibiogram pattern and prevalence of blaNDM and blaVIM genes among carbapenem resistant E. coli isolates in a tertiary care hospital. Our study will also help to identify molecular basis of Carbapenem resistance including treatment guideline. Materials and Methods: Cross-sectional study was performed during January’2021 to June’2022 time period. Identification of E. coli was followed by standard protocol and antibiotic sensitivity was done by Kirby-Bauer disk-diffusion method following CLSI guideline, using VITEK-2D-SYSTEM. Detection of genes was done by polymerase chain reaction (PCR). Results: Out of 1867 samples, 161 isolates were identified as E. coli, among which 90 were resistant to carbapenem. Among those, 50 (31%) were resistant to all three carbapenems. Among those, 100% were resistant to ampicillin, amoxycillin-clavulanic acid, cefuroxime, cefuroxime-axetil, cefoperazone-sulbactam, ceftriaxone, cefepime, piperacillin-tazobactam, nalidixic acid, ciprofloxacin; 52% were resistant to amikacin; 54% were resistant to gentamicin; 86% were resistant to cotrimoxazole; 22% were resistant to nitrofurantoin and 96% were sensitive to tigecycline; 100% were intermediate sensitive to colistin. blaNDM gene is detected in 17 (34%) isolates and blaVIM gene is detected in 2 (4%) isolates by PCR. Conclusion: E. coli leads to common clinical presentations such as urinary tract infection, blood stream infection, pneumonia, and wound infection. High burden of carbapenem resistant E. coli was associated with urinary indoor samples. Rising incidence of multi-drug-resistance occurs due to lack of infection control measures, irrational use of antibiotics. Continuous surveillance will prevent development of multi-drug-resistance and help to improve treatment guideline.

Prevalence of Metallo β-Lactamase Genes Among MDR Pseudomonas <i>Aeruginosa</i> Isolated from Different Sources in Baghdad

Background: Pseudomonas aeruginosa is a gram-negative apportunistic pathogen that has ability to couse different type of infections and charecterised by their high resistance to commonly used antibiotics via different stratiges. Objective: The objective of this study is to detect the prevalence rate of MβL gene among MDR Pseudomonas aeruginosa. Methods: Forty clinical isolates of Pseudomonas aeruginosa were obtained from different hospitials in Baghdad/Iraq. Their identification was confirmed by using 16s rDNA as a housekeeping gene (reference gene). Specific primers were used to detect 3 types of Metallo β-lactamase (MβL) genes vim, spm1, and imp1 genes followed by sequencing the amplified fragment which was analyzed by Geneious software. Antibiotic sensitivity test for 15 antimicrobial agents was done using the Kirby-Bauer disc diffusion method. Results: The revealed resistance pattern was as following: 100% for the combination of Trimethoprim/Sulphamethoxazole and Nitrofurantoin, 95% for Tigecycline, 82.5% for Ciprofloxacin, 67.5% for Cefepime, 60% for Levofloxacin, 57.5% for Carbenicillin, 55% for Piperacillin, 50% for Amikacin, 47.5% for Tobramycin, 45% for both Imipenem and Ceftazidime, 27.5% for piperacillin/tazobactam, 22.5% for Aztreonam and 7.5% for Colistin. More than half (55%) of isolates were positive for MβL enzymes production during phenotypically assessed by combined disc test. The MIC of meropenem ranged from 16µg/ml to 32 µg/ml. The percentage of MβL genes among the total isolates during conventional PCR was as follows: 95% for vim, 25% of the isolates harbored both vim and imp1, while spm 1 are negative in all isolates. The result of the study explained that 10 isolates from the antibiotic susceptibility test were resistant to 10-14 antimicrobial agents that harbored both vim and imp1 genes. Conclusions: MβL gene could be used as a genetic marker to determine the degree of resistance in MDR P. aeruginosa which are more resistant than other isolates that have one gene of MβL responsible for break the β-lactam ring then inactivating the β-lactam antibiotic.

Evaluation of the Causative Microorganisms and Antibiogram Results in Women with Vaginal Swab Culture Taken with Prediagnosis of Vaginitis

Aim: Vaginitis occurs when the vaginal flora is disturbed. This study aimed to evaluate the demographic data, causative microorganisms, and antibiogram results of women who underwent vaginal swab culture with a prediagnosis of vaginitis. Methods: Vaginal swab samples from 314 women who visited the Kafkas University Department of Obstetrics and Gynecology were included in the study. Women with immunosuppressive diseases, gynecological malignancies, and IUD use were excluded. Vaginal discharge or swab samples were Gram stained and cultured on various media. Microorganisms were identified using conventional and biochemical methods, and antibiotic susceptibility tests were performed using the Kirby-Bauer disk diffusion method, according to the EUCAST guidelines. Statistical analyses were performed using SPSS, with categorical variables assessed using the chi-square test or Fisher's exact test, and continuous variables assessed using the Mann-Whitney U test. The study complied with the recommendations of the Declaration of Helsinki for human biomedical research and was approved by the Non-Interventional Clinical Research Ethics Committee of the Kafkas University Faculty of Medicine. Results: The median age of 314 women included in this study was 39 (20-69) years. . In total, 73.6% (n=231) were premenopausal, 24.5% (n=77) were postmenopausal, and 1.9% (n=6) were pregnant. The most common complaint was abdominal/pelvic pain (142, 45.2%). Vaginal cultures from 123 women (39.1%) showed the growth of different microorganisms. The most common causative microorganism was Escherichia coli (41.5%). According to the antibiogram results, the most sensitive antibiotic was gentamicin (65.9%), and ampicillin (52.8 %) was the most resistant. Conclusion: It is important to quickly and accurately identify microorganisms involved in the etiology of the correct treatment.

Antibiotic Resistance Patterns of Pseudomonas aeruginosa Bacterial Species Isolated from Various Clinical Samples

Pseudomonas aeruginosa infections have become a real burden in healthcare settings, contributing substantially to nosocomial infections. The emergence of several drug-resistant strains was the major issue causing massive mortality. Multiple-drug resistant Pseudomonas aeruginosa isolates containing beta-lactamase were becoming more prevalent. Objective: To investigate and characterize the antibiotic resistance patterns of Pseudomonas aeruginosa isolated from different clinical samples. Methods: A total of 618 different clinical samples including blood, pus and urine samples were collected from the patients visiting Indus Medical College Hospital Tando Muhammad Khan, Sindh, Pakistan. All the clinical samples were processed for the isolation of bacterial species using specific culture media. The identification of Pseudomonas aeruginosa strains was achieved based on Gram’s staining and certain biochemical tests including Cetrimide test. Moreover, antibiotic susceptibility testing was determined by Kirby-Bauer disc diffusion method. Results: A total of 452 bacterial strains were isolated and pure cultured from different clinical samples. Among these, 60.62% were Gram-negative and 25% of the total isolates were found to be Pseudomonas aeruginosa strains. Antibiotic sensitivity testing results revealed the highest resistance ratio of Pseudomonas aeruginosa strains against Ticarcillin (46.02%), while Colistin showed the lowest resistance (3.54%). Overall, 14.15% of the isolates of Pseudomonas aeruginosa strains were found to be multi-drug-resistant bacteria. Conclusion: The results of the present study reveal an increased ratio of antibiotic resistance particularly of Ticarcillin, piperacillin and imipenem in Pseudomonas aeruginosa isolated from various clinical samples.

Significance of Modified Hodge Test in Carbapenemase Detection: A Brief Insight

Neonatal sepsis is one of the leading causes of neonatal deaths. A. baumannii-calcoaceticus is the most notorious bacterial agent. Carbapenems are the most important antibiotics and modified Hodge Test is considered as important phenotypic method for observing Carbapenemase production. Objective: To evaluate the efficacy rate of Modified Hodge Test, for detection of Carbapenem resistance. Methods: A cross sectional study was conducted at department of pathology, Nishtar Medical University, Multan from August 2023 to September 2023. The blood samples of suspected cases of sepsis were collected and after isolation of Acinetobacter baumannii sensitivity of multiple antibiotics were checked by disc diffusion method. Carbapenem resistance was re-evaluated by Modified Hodge Test using Meropenem disc (10 µg). All data were entered and analyzed by SPSS version 23.0. Results: Total samples of neonatal sepsis were 182. 83 (45.6%) were culture positive for bacterial growth. Among the positive samples 26 (31.3%) were isolated as Acinetobacter baumannii. Kirby-Bauer disc diffusion method was used to check sensitivity of multiple antibiotics including Carbapenems. Out of 26 Acinetobacter isolated samples, 16 were found to be Carbapenem resistant by this method. Modified Hodge test was used to re-confirm Carbapenem resistance. Out of 16 Meropenem resistant cases this phenotypic test only detected 5 cases (31.25%). Conclusions: Staphylococcus aureus followed by Acinetobacter baumannii were isolated predominantly and Carbapenem resistance has markedly increased. In contrast to a study conducted in 2010 in Pakistan on MHT effectiveness where effectiveness of MHT for Carbapenemase detection was satisfactory, our results reveled that some other techniques should be introduced for Carbapenemase detection as Modified Hodge test did not give satisfactory results

Trends in Antimicrobial Resistance of Uropathogens Isolated from Urinary Tract Infections in a Tertiary Care Hospital in Dhaka, Bangladesh.

Background/Objectives: Urinary tract infection (UTI) is a prevalent microbial infection in medical practise, leading to significant patient morbidity and increased treatment costs, particularly in developing countries. This retrospective study, conducted at a tertiary care hospital in Dhaka, Bangladesh, aims to examine the antimicrobial resistance (AMR) patterns of uropathogens and evaluate whether these patterns are influenced by demographic factors such as gender, age, or patient status. Methods: Standard microbiological techniques were used to identify uropathogens, and AMR patterns were determined using the Kirby-Bauer disc diffusion method. Results: Out of 6549 urine samples, 1001 cultures were positive. The infection was more prevalent in females compared to males. The incidence of UTIs in children aged 0-10 years accounted for 12.59% of the total cases, with this age group also exhibiting the highest rate of polymicrobial infections. Among the bacterial uropathogens, 71.19% of isolates were multidrug resistant (MDR) and 84.27% were resistant to at least one antibiotic. Escherichia coli (n = 544, 73.90% MDR) and Klebsiella species (n = 143, 48.95% MDR) were the most common Gram-negative uropathogens, while Enterococcus species (n = 78, 94.87% MDR) was the predominant Gram-positive isolate in this study. Our results indicate that most uropathogens showed resistance against ceftazidime, followed by cefuroxime, trimethoprim-sulfamethoxazole, amoxicillin-clavulanate, and netilmicin. Moderate levels of resistance were observed against ciprofloxacin, levofloxacin, aztreonam, and cefpodoxime. Conclusions: Amikacin was observed to be effective against Gram-negative uropathogens, whereas cefixime was more active against Gram-positive microorganisms, such as Enterococcus species. Moreover, a principal coordinate analysis (PCoA) depicted no significant influence of gender, patient status, or age on AMR patterns. For the continued usefulness of most antibiotics, periodic analysis of the AMR patterns of uropathogens can help assess the rise of MDR bacteria, and therefore guide the selection of appropriate antibiotic treatment strategies.

Prevalence of Antimicrobial Resistant Escherichia coli from Sinking Creek in Northeast Tennessee.

Antibiotic resistance (AR) is a critical global health threat exacerbated by complex human-animal-environment interactions. Aquatic environments, particularly surface water systems, can serve as reservoirs and transmission routes for AR bacteria. This study investigated the prevalence of AR E. coli in Sinking Creek, a pathogen-impacted creek in Northeast Tennessee. Water samples were collected monthly from four sites along the creek over a 6-month period. E. coli isolates were cultured, identified, and tested for susceptibility to eight antibiotics using the Kirby-Bauer disk diffusion method and broth disk elution method for colistin. Data were analyzed to determine the prevalence of AR and multidrug resistance (MDR) among isolates. Of the 122 water samples, 89.3% contained E. coli. Among the 177 isolates tested, resistance was highest to ciprofloxacin (64.2%) and nitrofurantoin (62.7%), and lowest to fosfomycin (14.1%) and colistin (6.0%). Significant differences in resistance to ceftriaxone and amoxicillin/clavulanic acid were observed between sampling sites. MDR was prevalent in 47.5% of isolates, with 5.1% resistant to seven antibiotics. The most frequent MDR patterns (6.8%) included three antibiotics: ceftriaxone, ciprofloxacin, and nitrofurantoin. The high prevalence of AR E. coli in Sinking Creek poses a significant public health risk, highlighting the need for ongoing surveillance and intervention strategies to prevent the spread of AR bacteria.

Isolation of Nutmeg Essential Oil (Myristica fragrans houtt) From Aceh Indonesia and Their Antioxidant and Antibacterial Activities

This study aims to isolate the nutmeg essential oil (Myristica fragrans Houtt) from Aceh Indonesia and evaluate their biological activity. The antioxidant activity of the nutmeg essential oils (Myristica fragrans Houtt) was determined by DPPH (1,1-difenil-2-pikrihidrazil) assay. The DPPH assay showed that arillus essential oil (AMFH) has the highest antioxidant activity with the IC50 values was 216,695 ppm. The chemical composition of the AMFH was perfomed by Gas Chromatography-Mass Spectroscopy (GC-MS), and the results showed that AMFH contains Terpinen-4-ol (T-4-ol), α-Terpineol (α-T), Safrole (Saf) and Myristicin (Myr) with the percentage area of 11.20%; 1.83%; 5.10%; and 27.80% respectively. The AMFH was isolated by column chromatography and four fractions were obtained, namely AMFH1; AMFH2; AMFH3; and AMFH4 fractions. The DPPH assay showed that the AMFH3 fraction showed excellent antioxidant activity with the IC50 values of 59.329 ppm. The AMFH3 fraction was than reisolated by using by column chromatography to obtain four subfractions namely AMFH3A; AMFH3B; AMFH3C; and AMFH3D. The DPPH assay showed that the subfraction of AMFH3A has the highest antioxidant activity with the IC50 values of 98.993 ppm. The antibacterial activity of AMFH3A subfractions was evaluated by Kirby Bauer-Disc diffusion method, and the results showed that AMFH3A subfraction showed slightly higher activity against Staphylococcus epidermidis and Staphylococcus aureus with the diameter inhibition of 14.28 mm and 12.26 mm respectively. The chemical composition of the AMFH3A subfraction was performed by GC-MS, and the results showed that AMFH3A subfraction contains Terpinen-4-ol (T-4-ol), α-Terpineol (α-T), Safrole (Saf) and Myristicin (Myr) with the percentage area of 14.37%; 2.16%; 7.36%; and 54.77% respectively.

ANTIBACTERIAL EFFICACY OF BACTERIOPHAGES AGAINST VIBRIO CHOLERAE

This study investigates the use of bacteriophages as an alternative antibacterial approach to combat antibiotic-resistant Vibrio cholerae, a major public health concern. Vibrio cholerae strains were identified through culture on TCBS agar, microscopy, and biochemical tests (catalase, oxidase, indole, and citrate). Antibiotic susceptibility was assessed using the Kirby-Bauer disk diffusion method across five antibiotics: tetracycline, norfloxacin, ampicillin, ciprofloxacin, and erythromycin. Results showed resistance to ampicillin, tetracycline, and erythromycin, while strains remained susceptible to norfloxacin and ciprofloxacin Five bacteriophages against Vibrio cholerae were isolated from 50 wastewater samples, and only two (F1 and F2) showed lytic activity, forming clear plaques. These two lytic phages were further purified and characterized for stability across different temperatures, pH levels, and host range. The isolated phages were tested for host range against six Vibrio cholerae strains, with F1 lysing five strains and F2 lysing three, and demonstrated stability across temperatures (20°C to 55°C) and pH levels (4 to 9). They remained active across a wider temperature and pH range demonstrating their potential for therapeutic use. The study shows that these phages are highly specific, targeting only Vibrio cholerae strains from various sources without affecting other bacterial species. This specificity makes them safer for therapeutic use, as they are less likely to disrupt the body’s natural bacterial flora. Further genomic studies are recommended to characterize the genetic makeup of these phages, optimizing their application in cholera treatment. This study provides critical insights into the potential of bacteriophages as an alternative treatment for antibiotic-resistant Vibrio cholerae.

Antimicrobial Susceptibility Patterns of Bacteria Associated with Upper Respiratory Tract Infections in North and South Waziristan, Pakistan

Background: Upper respiratory tract infections (URTIs) are a significant cause of outpatient visits globally, with antimicrobial resistance (AMR) presenting a growing challenge to effective treatment. In Pakistan's tribal regions, limited healthcare access exacerbates this issue.Objective: To determine the prevalence of bacterial pathogens causing URTIs and assess their antimicrobial susceptibility patterns in North and South Waziristan, Pakistan.Methods: This cross-sectional study involved 300 throat swabs collected from outpatients between January and June 2023. Samples were inoculated on Blood, MacConkey, and Chocolate agars, followed by incubation at 37°C for 24 hours. Standard biochemical tests were used for bacterial identification, and the Kirby-Bauer disc diffusion method assessed antimicrobial susceptibility. Statistical analysis was performed using SPSS version 25.0, with p-values ≤ 0.05 considered significant.Results: Pathogens were isolated in 93% of samples, with Staphylococcus aureus (40.2%), viridans group streptococci (35.7%), and Streptococcus pyogenes (17.1%) being the most common. Resistance was highest in viridans group streptococci (33.7% to tazobactam) and lowest in Streptococcus pyogenes (26.3%).Conclusion: The high rates of resistance, particularly in viridans group streptococci, highlight the need for targeted interventions to mitigate AMR in this region.

Physicochemical characteristics and antibiotic resistance patterns of enteric bacteria isolated from harvested rainwater (HRW) in Oraukwu, Anambra State, Nigeria

infections temperature, colour, turbidity, DO, TDS, TSS, alkalinity, hardness, chloride, and some heavy metals of the water samples were examined using APHA method. Bacteriological analyses were performed using the membrane filtration technique. Colonies formed were counted and expressed in CFU/100mL. Enteric bacteria were enumerated and characterized by their morphological characteristics and biochemical tests. Axenic cultures of the isolates were further subjected to antimicrobial susceptibility testing (AST) using the modified Kirby-Bauer disc diffusion method, based on the guidelines by CLSI. Results revealed that physicochemical parameters and some heavy metals were within acceptable limits, except for Fe (0.01-0.72 mg/L) and Pb (0.01-0.25 mg/L). Total bacterial counts ranged from 1.2×104 to 6.8×104 CFU/100mL, indicating high contamination. Morphological characteristics revealed twelve (12) isolates of enteric bacteria, comprising Escherichia coli (41.67%), Salmonella sp. (33.33%) and Shigella sp. (25%). All the isolates exhibited 100% resistant to augmentin and tetracycline, but showed varying degrees of susceptibilities; E. coli to levofloxacin (60%), Salmonella sp. to ertapenem, imipenem, levofloxacin and nalidixic acid (100%), and Shigella sp. to ceftriaxone and ertapenem (100%). ‘First flush’ diverters are recommended to be installed within the water collecting system, in order to divert runoff from the rooftop after a period of no rainfall. Antibiotics which the isolates were susceptible to are recommended for the treatment of infections caused by these pathogens.

Genetic and in-silico approaches for investigating the mechanisms of ciprofloxacin resistance in Salmonella typhi: Mutations, extrusion, and antimicrobial resistance

Salmonella enterica serovar Typhi spreads typhoid infection in humans through the consumption of contaminated food and water. Poor sanitation plays a pivotal role in its dissemination. Over time, the bacterium has acquired resistance to many promising antibiotics, posing a growing global health concern and hindering the achievement of sustainable development goals. This study aims to elucidate the molecular complexity of fluoroquinolone resistance, a first-line treatment for typhoid infection. To achieve this aim, 80 clinical isolates were collected from various diagnostic laboratories. These isolates were confirmed based on morphological characteristics and biochemical tests. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) isolates were identified using the Kirby-Bauer disc diffusion method. The mechanism of ciprofloxacin resistance was investigated by sequencing the quinolone resistance-determining region (QRDR) genes and identifying the presence of the qnrS1 gene. As a result of this study, 60 % of isolates showed resistance to ciprofloxacin. At the same time, the qnrS1 gene was present in all the selected strains while mutation analysis identified significant mutation in QRDR of DNA gyrase subunit A (gyrA) and Topoisomerase IV (parC) gene. The combinatorial effect was further investigated by downloading 286 draft genomes. The Mutation analysis reveals significant mutations at gyrA S83F, gyrA D87N, gyrA S83Y, gyrB S464F, parC S80I, and parE L416F. Additionally, docking analysis indicates reduced binding affinity and altered solvent accessibility, which show the structural changes at mutation sites. This study provides crucial insights that mutation reduces the binding affinity while qnrS1 acts as a transport channel to extrude the ciprofloxacin. In the future, further validation through experimental mutagenesis is recommended, for targeted therapeutic interventions against the mounting threat of antibiotic-resistant S. Typhi.

Antibiotic Susceptibility Pattern of Pseudomonas aeruginosa and Detection of Virulence Genes in a Tertiary Care Hospital, Kathmandu, Nepal

Pseudomonas aeruginosa is one of the most common causes of hospital-acquired infections. It threatens worldwide public health because of its intrinsic antibiotic resistance and virulence. In this context, this research aimed to determine the occurrence of P. aeruginosa in a clinical setting, examine its susceptibility to antibiotics, and detect the presence of virulence genes, viz. exoY, oprL and toxA in all isolates. It was a cross-sectional study carried out from June 2022 to December 2022. A total of 1356 clinical specimens were collected and processed in the laboratory for Gram staining, culture techniques, and biochemical tests. The Kirby-Bauer disk diffusion method was applied to examine the antibiotic susceptibility pattern and conventional PCR was used to detect the virulence genes in all confirmed P. aeruginosa isolates. 40.5% of specimens showed bacterial growth, of which only 3.02% were identified as P. aeruginosa. Among them, 61.0% were multidrug resistant and 29.2% were β-lactamase producers. Aztreonam (70.7%) was the most effective antibiotic. Among all P. aeruginosa isolates, 68.3% isolates were exoY positive, 61.0% were oprL positive and 56.1% were toxA positive. Strategic interventions are required to stop the emergence and spread of antimicrobial resistance as a result of the isolation of multidrug resistant (MDR) isolates carrying these virulence genes. This study can benefit the medical staff and the entire community in building a surveillance system and enhancing infection control procedures.