Etest Research Articles

Ceftriaxone-resistant viridans streptococci bacteraemia among patients treated at a large comprehensive cancer care centre: a retrospective eighteen-year study.

Viridans streptococci (VS) are opportunistic oral commensals and a common cause of bacteraemia in neutropenic patients. In this retrospective single centre cohort study, we investigated the prevalence of ceftriaxone resistance in VS (CRO-R VS) blood isolates between January 2005 and December 2022 from patients treated at a tertiary care hospital. Blood culture isolates were identified using biochemicals and mass spectrometry. Susceptibility testing was performed by Kirby-Bauer and Epsilometer tests. Demographic data, clinical outcomes and antimicrobial use were assessed through electronic medical record review. Among 791 patients with VS bacteraemia, 31 (4%) had confirmed CRO-R VS bacteraemia over the 18-year period; 20/31 (65%) were patients also treated at the Fred Hutchinson Cancer Center and were the focus of this study. Of these 20 patients, 18 (90%) had a known haematologic malignancy; 14 (70%) had undergone haematopoietic cell transplant (HCT); 18 (90%) were neutropenic at the time of culture. Two (10%) patients died within 30 days of CRO-R VS bacteraemia. All the CRO-R isolates (20/20) were members of the Streptococcus mitis group, 12 were multi-drug resistant; all were susceptible to vancomycin. Most patients received vancomycin once blood cultures were positive for a Gram-positive organism. During the study period, the frequency of VS isolate susceptibility testing increased; however, there was no concomitant increase in the percentage of CRO-R isolates at our facility. These data are important in an era where cefepime monotherapy is often used and reinforces the importance of routine resistance testing among VS bacteraemia.

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.

A Road Less Traveled: E-test Method for Antifungal Susceptibility Testing in Trichophyton mentagrophyte Isolates Among Patients Presenting With Dermatophytosis at a Tertiary Healthcare Center in North India.

Introduction Dermatophytosis is a common infection of the skin, hair, and nails caused by dermatophytes, a group of filamentous fungi capable of digesting and obtaining nutrients from keratin. Dermatophytes comprise three important genera: Epidermophyton, Microsporum,and Trichophyton. This study aimed to analyze the antifungal susceptibility patterns of Trichophyton mentagrophytes isolates using the epsilometer test (E-test) method. Material and methods This prospective observational study was conducted on clinically suspected cases of dermatophytosis. All samples, including skin scrapings, hair, and nails, were subjected to potassium hydroxide (KOH) examination followed by fungal culture. The Trichophyton mentagrophytes isolates were then subjected to antifungal susceptibility testing using the E-test method for the two most prescribed antifungals: itraconazole and fluconazole. Results In this study, one-third of the patients who tested positive for dermatophytosis belonged to the same family, with spouses being the most commonly affected. Tinea corporis was the most common clinical presentation, with Trichophyton mentagrophytes identified as the most common etiological agent. Itraconazole was more effective than fluconazole. Conclusion The current study demonstrated that antifungal susceptibility testing of dermatophytes using the E-test is easier and can be applied in routine laboratories as a screening method, serving as an alternative to broth microdilution.

Streptococcus pneumoniae among the children of Aden, Yemen: a cross-sectional report of post-pneumococcal conjugate vaccine.

Streptococcus pneumoniae cause a significant global health challenge. We aimed to determine nasopharyngeal carriage, serotypes distribution, and antimicrobial profile of pneumococci among the children of Aden. A total of 385 children, aged 2-17 years, were included. Asymptomatic samples were randomly collected from children in selected schools and vaccination centers. Symptomatic samples were obtained from selected pediatric clinics. The nasopharyngeal swabs were tested for pneumococci using culture and real time polymerase chain reaction (RT-PCR). Serotyping was done with a pneumotest-latex kit and antimicrobial susceptibility was tested by disc diffusion and Epsilometer test. The total pneumococcal carriage was 44.4% and 57.1% by culture and RT-PCR, respectively. There was a statistically significant association between carriage rate and living in single room (OR = 7.9; p = 0.00001), sharing a sleeping space (OR = 15.1; p = 0.00001), and low monthly income (OR = 2.02; p = 0.007). The common serotypes were 19, 1, 4, 5, 2, and 23. The proportion of non-pneumococcal conjugate vaccine (non-PCV13) serotypes was 24%. Pneumococci were resistant to penicillin (96.5%), cefepime (15.8%), ceftriaxone (16.4%), and amoxicillin-clavulanate (0%). Erythromycin, azithromycin, and doxycycline had resistance rates of 48%, 31%, and 53.3%, respectively. A high pneumococcal carriage rate was observed in Yemeni children, particularly in low-income households and shared living conditions. There was significant penicillin resistance at meningitis breakpoint. Furthermore, non-PCV13 serotypes were gradually replacing PCV13 serotypes. The findings underscore the urgent need for enhanced surveillance and stewardship to improve vaccination and antibiotic policies in Yemen.

Effects of different types of warm-ups on performance by young volleyball players

The study aimed to compare the impact of warm-up with dynamic stretching (DS), warm-up with foam roller (FR), and warm-up with a combination of FR and DS (CO) on the performance of movement indicators in tests conducted on young volleyball players (n = 8, age = 15.4 ± 0.5 years, height = 176.3 ± 8.6 cm, weight = 64.5 ± 10.9 kg) during the competition year 2021/2022. To assess the effects of warm-up methods (DS, FR, CO), performance in various movement tests was compared. The tests included the sit and reach test (SR), a 1 kg ball throw in a kneeling position (H1), squat jump (SJ), countermovement jump (CMJ), sit-up test (SU), E-Test (ET), and run to cones (RC). The One-way ANOVA analysis did not reveal significant differences in the effects of DS, FR, and CO warm-ups (p > .05) across all investigated indicators. The effect size coefficient (η2) indicated negligible differences (η2 < 0.01), except for the ET indicator, where a small effect size (η2 = 0.028, 95%CI: 0.04-0.31) favoured DS. These findings carry social importance as they contribute to enhancing the efficacy of warm-up routines, both in sports performance and health considerations.

Antimicrobial resistance profile of Enterococcus species and molecular characterization of Vancomycin resistant Enterococcus faecium from the fecal samples of newly diagnosed adult HIV patients in Dar es Salaam, Tanzania

BackgroundEnterococci are becoming clinically more important especially among immunocompromised patients. Of concern are vancomycin resistant enterococci (VRE) which have both intrinsic and acquired forms of resistance. This work aimed to determine the antimicrobial resistance patterns of Enterococcus spp. and characterize VRE isolate obtained from HIV-infected patient using whole genome sequencing (WGS).Methods:Antimicrobial susceptibility testing was done on 57 enterococci isolates by both the disk diffusion method and Epsilometer test (E-Test). WGS was performed on VRE isolate determined by E-test.ResultsOut of the 57 enterococci isolates; 58% (33/57) were E. faecalis, 39% (22/57) E. faecium and 4% (2/57) were E. gallinarum. The highest antimicrobial resistance was observed in E. faecalis isolates. The most prevalent antimicrobial resistance was observed towards quinupristin-dalfopristin (56%, 32/57), followed by ciprofloxacin (28%), tigecycline (18%), daptomycin (16%), chloramphenicol (14%), ampicillin and teicoplanin (2%). Multidrug resistance (MDR) was detected in 11% (6/57) of the isolates. Vancomycin resistance and high-level gentamycin resistance (HLGR) were observed in one E. faecium and one E. faecalis isolates respectively. The VRE was typed as ST80, carried vanA and other resistance genes for aminoglycosides, tetracyclines, quinolones and ampicillin. Furthermore, the isolate had chromosomal mutations responsible for quinolone (gyrA (p.S83I) and parC (p.S80I) and ampicillin (pbp5) resistance.ConclusionsThe detection of VRE, HLGR and MDR in the study settings underscores the sustained surveillance of VRE in high-risk groups and institution of infection control measures for prompt identification and isolation of carriers to prevent the spread of VRE in the community and hospital settings.

Genomic Characterization and Safety Assessment of Bifidobacterium breve BS2-PB3 as Functional Food.

Our group had isolated Bifidobacterium breve strain BS2-PB3 from human breast milk. In this study, we sequenced the whole genome of B. breve BS2-PB3, and with a focus on its safety profile, various probiotic characteristics (presence of antibiotic resistance genes, virulence factors, and mobile elements) were then determined through bioinformatic analyses. The antibiotic resistance profile of B. breve BS2-PB3 was also evaluated. The whole genome of B. breve BS2-PB3 consisted of 2,268,931 base pairs with a G-C content of 58.89% and 2,108 coding regions. The average nucleotide identity and whole-genome phylogenetic analyses supported the classification of B. breve BS2-PB3. According to our in silico assessment, B. breve BS2-PB3 possesses antioxidant and immunomodulation properties in addition to various genes related to the probiotic properties of heat, cold, and acid stress, bile tolerance, and adhesion. Antibiotic susceptibility was evaluated using the Kirby-Bauer disk-diffusion test, in which the minimum inhibitory concentrations for selected antibiotics were subsequently tested using the Epsilometer test. B. breve BS2-PB3 only exhibited selected resistance phenotypes, i.e., to mupirocin (minimum inhibitory concentration/MIC >1,024 μg/ml), sulfamethoxazole (MIC >1,024 μg/ml), and oxacillin (MIC >3 μg/ml). The resistance genes against those antibiotics, i.e., ileS, mupB, sul4, mecC and ramA, were detected within its genome as well. While no virulence factor was detected, four insertion sequences were identified within the genome but were located away from the identified antibiotic resistance genes. In conclusion, B. breve BS2-PB3 demonstrated a sufficient safety profile, making it a promising candidate for further development as a potential functional food.

Avoiding the Danger of Rising Resistance in Cutibacterium acnes: Criticality of Benzoyl Peroxide and Antibiotic Fixed Combinations

Background: Antibiotic resistance is a global concern, with several countries reporting resistance in >50% of Cutibacterium acnes (C. acnes) strains. Combination formulations containing an antibiotic and the antimicrobial benzoyl peroxide (BPO) may reduce this resistance risk, especially with prolonged use. This four-part study tested susceptibility of 31 C. acnes clinical strains to antibiotics alone or in combination with BPO.
 Methods: Part 1: C. acnes susceptibility to single-drug antibiotics was assessed via minimum inhibitory concentration (MIC) values obtained from epsilometer tests, with lower MIC indicating higher susceptibility. Part 2: Susceptibility to fixed-dose antibiotic/BPO combination products (branded/in-development) was determined by measuring zone of inhibition using agar diffusion method, with larger diameter indicating increased bacterial inhibition. Part 3: The effect (synergistic, additive, antagonistic, or neutral) of combining clindamycin with BPO on C. acnes inhibition was evaluated using a checkerboard assay, wherein two test compounds are combined in varying concentrations. Part 4: Development of resistance was assessed using serial passage of bacterial cultures in increasing concentrations of clindamycin alone or in combination with BPO.
 Results: Part 1: All antibiotics tested—clindamycin, doxycycline, erythromycin, and minocycline—had similar activity. Susceptibility was highly strain dependent, as some C. acnes strains had elevated MIC—an indication of resistance—against different antibiotics. Part 2: For the 6 C. acnes strains that had no inhibitory zone (0 cm) with clindamycin alone, formulations with BPO enhanced activity against the same isolates (range: 0.8-2.2 cm with clindamycin phosphate 1.2%/adapalene 0.15%/BPO 3.1%, clindamycin phosphate 1.2%/BPO 5%, or clindamycin phosphate 1.2%/BPO 3.75%). Part 3: The combination of clindamycin and BPO resulted in an additive effect for 4 of the 7 acne-associated strains tested and was neutral for 3 strains. Part 4: Bacterial cultures repeatedly exposed to a combination of clindamycin and BPO did not develop resistance to C. acnes, which occurred with exposure to antibiotic alone.
 Conclusions: Overall, antibiotic susceptibility was highly strain dependent and antibiotic formulations with BPO exhibited enhanced activity against less susceptible C. acnes strains. Fixed combinations of BPO with an antibiotic may improve antimicrobial activity and protect against resistance development.
 
 Funding: Ortho Dermatologics.

Determination of Vancomycin Minimum Inhibitory Concentration in Methicillin-resistant Staphylococcus Aureus by Various Phenotypic Methods: A Cross-sectional Study

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) has become a global threat, causing nosocomial and community-acquired infections, thus significantly contributing to morbidity and mortality. These organisms often exhibit Multidrug Resistance (MDR) to various groups of antimicrobials. The emergence of reduced susceptibility to vancomycin and resistance further exacerbates the problem, leaving clinicians with few therapeutic options to treat serious, life-threatening infections. Aim: To determine the vancomycin susceptibility of MRSA using various phenotypic methods. Materials and Methods: The present cross-sectional study was conducted in the Department of Microbiology, SHKM Government Medical College, Nalhar, Haryana, India, from February 2019 to January 2020. All MRSA isolates were included, totaling 66 MRSA isolates. MRSA isolates were screened using the cefoxitin disc (30 μg) according to the Clinical and Laboratory Standards Institute (CLSI) recommended disc diffusion method. The Minimum Inhibitory Concentration (MIC) of vancomycin was determined using phenotypic methods such as broth dilution, agar dilution and Epsilometer test (E-test). Demographic details such as age, sex, site of the sample and diagnosis were recorded. Statistical analysis was performed using the Pearson’s product-moment correlation. The significance level was set at a probability of <0.05 with a confidence interval of 95%. Results: A total of 66 (30.3%) isolates of Staphylococcus aureus (S. aureus) were identified as MRSA using standard laboratory tests and were studied for vancomycin MIC using phenotypic methods: Broth dilution, agar dilution and E-test. Vancomycin- intermediate S. aureus (VISA) was observed in 54.5%, 42.4% and 51.5% of MRSA by E-test, agar dilution and broth dilution, respectively. The presence of Vancomycin-resistant S. aureus (VRSA) was not detected in the region. When compared with broth dilution, E-test results demonstrated higher accuracy (97%) than agar dilution (90.9%). Conclusion: The present study highlights the emergence of VISA in more than 40% of the MRSA in the region. The higher MIC of vancomycin emphasises the need for strict adherence to antibiotic prescription guidelines to prevent further emergence of vancomycin resistance.

Analysis of Susceptibility or Resistance to Antimicrobial Agents.

Here were described the main three methods being used for analysis of antibiotic susceptibility or resistance of Streptococcus suis clinical isolates to antimicrobial agents: the Kirby-Bauer disk diffusion, the epsilometer test (E test), and the broth microdilution test. In each case, procedures, results, and interpretation are described, as well as their advantages or limitations when proceeds.

Bacteriological Profile and Antibiogram of Aerobic Blood Culture Isolates among Suspected Blood Stream Infections: A Cross-sectional Study

Introduction: Bloodstream Infections (BSIs) are important causes of morbidity and mortality worldwide. Blood culture is the most important diagnostic tool for BSI. The epidemiology and outcome of BSI are constantly changing due to increasing antimicrobial resistance, changing patterns of antibiotic drug usage, and the increased use of transient or permanent medical devices. Thus, regular monitoring of the bacterial aetiology of BSI and their antibiograms is necessary. Aim: To determine the bacteriological profile and antibiotic susceptibility patterns among suspected BSI patients. Materials and Methods: A hospital-based cross-sectional study was carried out in the Department of Microbiology, Jawaharlal Nehru Institute of Medical Sciences (JNIMS), Imphal, Manipur, India, from September 2018 to August 2020. A total of 481 suspected BSI patients were included in the study. The blood culture samples were collected under aseptic conditions and cultured for seven days. The isolates were identified using conventional biochemical tests, and the antibiotic susceptibility pattern was determined by the Kirby-Bauer disk diffusion method and the epsilometer test (E-test). Methicillin resistance among the staphylococcal isolates was detected using the cefoxitin disk diffusion method. Data analysis was performed using EpiInfoTM version 7.0, and the Chi-square test was used as a statistical test. Results: A total of 150 (31.2%) blood samples were culture positive out of the 481 samples processed from suspected BSI patients. The predominant isolates were gram-positive, accounting for 113/150 (75.3%), while gram-negatives accounted for 37/150 (24.7%). Staphylococcus aureus, Pseudomonas aeruginosa, and Coagulase Negative Staphylococci (CoNS) were the primary pathogens isolated. Methicillin resistance was detected in 59 (54.6%) of the staphylococcal isolates {52 (54.7%) were Methicillin Resistant S. aureus (MRSA), and out of the 13 CoNS isolates, 7 (53.9%) were Methicillin Resistant CoNS (MRCoNS)}. The most susceptible drugs for gram-positives were vancomycin and linezolid, while aminoglycosides and imipenem were the most susceptible drugs for gram-negatives. Conclusion: The study highlighted the prevalence and pattern of aerobic bacterial isolates in BSI cases at JNIMS Hospital, as well as, the antibiotic susceptibility patterns of the isolates. Regular epidemiological studies of BSIs, regarding the pathogens and their antibiotic susceptibility patterns, are necessary to guide clinicians in choosing appropriate empirical therapy and to update the hospital antibiotic policy from time to time. This promotes rational antibiotic use and reduces resistance among bacteria.

Antibiotic Susceptibility Pattern of Cutibacterium acnes in Egyptian Acne Patients

Background. Recent studies have revealed that antibiotics are yielding unsatisfactory outcomes in certain patients with acne. Therefore, attention was drawn to antibiotic resistance as a rapidly growing problem that might lead to treatment failure. Objective. The study aims to assess the antibiotic susceptibility patterns of Cutibacterium acne isolates in a sample of Egyptian patients to the antibiotics most frequently prescribed for acne vulgaris. Methods. A total of 155 patients with moderate to severe acne were included in the study. Skin swab samples were collected and inoculated. Cutibacterium acnes was identified based on colonial morphology, Gram stain, and biochemical reactions and further confirmed by VITEK 2 automated systems. Antibiotic susceptibility tests were performed using minimum inhibitory concentrations determined by the Epsilometer test. Results. Cutibacterium acnes was detected in 50 samples (32.2%), alone in 17 (10.9%), and in combination with Staphylococci in 33 (21.3%) cases. The results of the antibiotic susceptibility testing revealed high resistance to erythromycin, followed by clindamycin, tetracycline, trimethoprim/sulfamethoxazole, and doxycycline. Conclusion. Cutibacterium acnes showed high resistance rates to most antibiotics used in the clinical treatment of acne vulgaris.

A comparative evaluation of colistin Minimum Inhibitory Concentration determination by reference broth microdilution with other commonly used phenotypic methods in Multidrug-Resistant Gram-negative bacilli

Background: over the past decade, the dependency on colistin as a last resort antibiotic has driven the global emergence of colistin resistance among many bacterial species. This study comparatively evaluated the colistin Minimum Inhibitory Concentration (MIC) by various phenotypic methods, including the reference method of Broth Microdilution (BMD), other approved methods of Colistin Broth Disk Elution (CBDE), and Colistin Agar Test (CAT) and widely available method of Epsilometer Test (E-test) among Multidrug Resistant (MDR) Gram-negative bacteria. Methods: ninety Gram-negative bacterial isolates that were resistant to three or more classes of drugs (MDR) were included in the study. All the MDR isolates were subjected to colistin susceptibility determination by BMD, CBDE, CAT, and E-test. Results: amongst 1118 samples, 90 (8.05%) samples yielded MDR Gram-negative bacilli. All the MDR Gram-negative isolates were colistin intermediate by all four methods of phenotypic colistin susceptibility. Three Acinetobacter baumannii and two Klebsiella pneumoniae isolates that had MIC of 2 μg/mL by BMD, displayed MIC of <1 μg/mL by CBDE and CAT. Three isolates (2 Citrobacter koseri and 1 Enterobacter spp.) showed higher MIC by the E-strip method in comparison to BMD. Conclusions: our study holds significance, as there is a paucity of data comparing the four phenotypic methods for colistin MIC determination; BMD is the most reliable, gold standard method, but it is labor-intensive and requires technical expertise. In the present study, CBDE and CAT methods showed good concordance with BMD, and are easy to perform with limited logistics. Thus, they can be used as an alternative to BMD. We found that even though the Etest method was less accurate, it can still be used with caution to exclude the possibility of colistin resistance.

The Molecular Investigation of the mecA Gene and Antibiotic Susceptibility Pattern of Staphylococcus aureus and Staphylococcus epidermidis Isolated from Patients with Immune System Disorders at Omid Hospital, Isfahan, Iran

Background: At present, antibiotic-resistant staphylococci, especially methicillin-resistant strains, are prevalent agents of infections in medical centers and hospitals. The objective of the present investigation was to discern and trace the methicillin resistance gene harbored in two bacterial strains, namely Staphylococcus aureus and Staphylococcus epidermidis, obtained from clinical specimens gathered from patients exhibiting immune system deficiency at Omid hospital located in Isfahan. Methods: The present investigation was conducted utilizing a descriptive cross-sectional approach. Initially, a total of 70 clinical isolates comprising 35 isolates of S. aureus and 35 isolates of S. epidermidis were obtained from patients who were diagnosed with immunodeficiency and admitted to Omid Hospital located in Isfahan, Iran, from January 2017 to April 2018. After the characterization of the isolates via morphological and biochemical assessments, subsequent evaluation of their antibiotic sensitivity was performed through the utilization of disk diffusion and Epsilometer test (E-test). Then, the identification of the isolates was conducted using the colony PCR method incorporating primers (MCF, MCR, GAIF, and GAIR) and elucidated through molecular analysis. Results: In this study, all isolates of S. aureus were resistant to cefoxitin and the MIC of this antibiotic was confirmed using E-test. However, of 35 S. epidermidis isolates, 30 isolates (85.7%) were resistant to oxacillin and 5 isolates (14.3%) were sensitive to oxacillin. According to the molecular findings, out of 35 isolates of methicillin-resistant S. aureus, 4 isolates (11.4%) had the mecA gene, and out of 35 isolates of S. epidermidis, 10 isolates (28.5%) had the mecA gene. Conclusion: The present study revealed that precise detection of methicillin resistance in the aforementioned bacterial strains necessitates the employment of both phenotypic and genotypic methods. The frequency of the mecA gene in methicillin-resistant S. aureus (MRSA) was found to be declining. The incidence of methicillin-resistant S. epidermidis (MRSE) is on the rise.

In Vitro Susceptibility of Clinical Isolates to Ceftriaxone Alone and Ceftriaxone in Combination With Sulbactam or Tazobactam: A Comparative Study of Broad-Spectrum β-Lactam Antibiotics in India.

Background This study was designed to evaluate the current in vitro susceptibility of clinical isolates to broad-spectrum β-lactam antibiotics. Methodology Bacterial isolates, cultured from 180 non-repetitive clinical samples between April and November 2022 at three hospitals in India, were used to evaluate the minimum inhibitory concentration (MIC) of broad-spectrum β-lactam antibiotics using the Epsilometer test (E-test) method. Test antibiotics were ceftriaxone and ceftriaxone in combination with β-lactamase inhibitors (BLIs) sulbactam and tazobactam. Comparator antibiotics included amoxicillin + BLI clavulanic acid, piperacillin + tazobactam, cefotaxime, and cefepime. The MIC values obtained were used to assess the susceptibility of the isolates and to compute the efficacy ratios (ERs) of the antibiotics. Results Among the 180 clinical isolates, ~89% were gram-negative bacteria, the most prevalent ones being Escherichia coli and Klebsiella pneumoniae. Of the gram-negative isolates, ~37% were susceptible/intermediately susceptible to ceftriaxone, and ~29% were susceptible to ceftriaxone + BLIs. The test antibiotics had ER >10 against 85%-95% E. coli isolates, whereas comparator antibiotics had ER >10 against 31%-68% isolates. The differences between the test antibiotics and piperacillin + tazobactam or cefotaxime were statistically significant. Ceftriaxone, ceftriaxone + sulbactam, and ceftriaxone + tazobactam had ER >10 against 78%, 100%, and 90% of K. pneumoniae isolates, while the corresponding percentages for cefotaxime, piperacillin + tazobactam, and cefepime were 100%, 64%, and 80%, respectively. The difference between ceftriaxone + BLIs and piperacillin + tazobactam was statistically significant. Ceftriaxone + BLIs had ER >10 against all E. coli isolates producing extended-spectrum β-lactamases (ESBLs); the percentage of isolates was significantly higher than that for piperacillin + tazobactam. Ceftriaxone + tazobactam had ER >10 against all ESBL-producing K. pneumoniae isolates; ceftriaxone and ceftriaxone + sulbactam had ER ranging 6-10. Conclusions Ceftriaxone and ceftriaxone in combination with sulbactam and tazobactam are promising antibiotics to explore against prevalent infectious microorganisms such as E. coli and K. pneumoniae. Ceftriaxone + tazobactam also holds promise against ESBL-producing variants.

SCREENING OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS AMONG HEALTHCARE WORKERS AND THEIR ANTIBIOTIC SUSCEPTIBILITY PATTERN IN A TERTIARY CARE HOSPITAL

Objective: Colonization of Staphylococcus aureus in the nasal flora has been proven to play an important role in the transmission of infections. Health care workers carrying Staphylococcus aureus in their nose or skin play an important role in cross-contamination and thus result in Methicillin-resistant Staphylococcus aureus (MRSA) related hospital-acquired or community-acquired infections. Implementation of hand hygiene methods and standard precautions are helpful in reducing transmission and controlling spread. Screening for carriage of MRSA is fundamental step in nosocomial infection control. The present study was undertaken to determine the prevalence of MRSA carriage rate and study their antibiogram.
 Methods: A cross-sectional study was conducted for a period of six months and samples from 185 HCWs working in high-risk areas were processed by standard protocols. As per CLSI guidelines, MRSA detection by disc diffusion method using Cefoxitin disc (30μg) and further determined by Epsilometer test (E-test) by interpreting Minimum inhibitory concentration (MIC) values (mcg/ml).
 Results: Out of 185 nasal swabs, 53 were Staphylococcus aureus isolates. MRSA colonization is seen in (8.64%) samples. Preponderance was seen in staff nurses (10.16%). Antibiogram of MRSA isolates showed sensitivity to Vancomycin and linezolid.
 Conclusion: The present study was undertaken to screen nasal carriage of MRSA among healthcare workers, as they pose a potential risk factor for nosocomial transmission leading to MRSA outbreaks. The strengthening of Infection prevention and control measures institutionalization of antimicrobial stewardship programs helps in curbing the spread of MRSA.

Osteosynthesis-associated infection in maxillofacial surgery by bacterial biofilms: a retrospective cohort study of 11 years

ObjectivesThe aim of this retrospective cohort study was to determine risk factors for osteosynthesis-associated infections (OAI) with subsequent necessity of implant removal in oral and maxillofacial surgery.Materials and methodsA total of 3937 records of patients who received either orthognathic, trauma, or reconstructive jaw surgery from 2009 to 2021 were screened for osteosynthetic material removal due to infection. Treatment-intervals, volume of applied osteosynthetic material, and respective surgical procedures were also assessed. Moreover, intraoperatively harvested microbial flora was cultured and subsequently identified by MALDI TOF. Bacteria were then screened for antibiotic resistance via VITEK system or, if necessary, via agar diffusion or epsilometer test. Data was analyzed utilizing SPSS statistical software. For statistical analysis of categorical variables, chi-square tests or Fisher exact tests were used. Continuous variables were compared via non-parametric tests. The level of significance for p-values was set at < 0.05. Descriptive analysis was also performed.ResultsThe lower jaw was more prone to OAI than the mid face region. Larger volumes of osteosynthetic material led to significantly more OAI, resulting in reconstruction plates bearing the highest risk for OAI especially when compared to small-volume mini-plates frequently applied in trauma surgery. Among OAI associated with implant volumes smaller than 1500 mm3, the detection of Streptococcus spp., Prevotella spp., Staphylococcus spp., and Veillonella spp. was significantly elevated, whereas implant volumes larger than 1500 mm3 showed a significant increase of Enterococcus faecalis, Proteus mirabilis and Pseudomonas aeruginosa. High susceptibility rates (87.7–95.7%) were documented for 2nd- and 3rd-generation cephalosporines and piperacillin/tazobactam.ConclusionHigh material load and lower jaw reconstruction bear the greatest risks for OAI. When working with large volume osteosynthetic implants, gram-negative pathogens must be considered when choosing an appropriate antibiotic regime. Suitable antibiotics include, e.g., piperacillin/tazobactam and 3rd-generation cephalosporines.Clinical relevanceOsteosynthetic material utilized in reconstructive procedures of the lower jaw may be colonized with drug-resistant biofilms.

MINIMUM INHIBITORY CONCENTRATION LEVELS OF MUPIROCIN BY E-TEST AMONG STAPHYLOCOCCUS AUREUS ISOLATES AND THEIR ANTIMICROBIAL SUSCEPTIBILITY PATTERN

Objective: This study was done to evaluate the susceptibility of Staphylococcus aureus to mupirocin and to determine the antimicrobial susceptibility pattern of Staphylococcus aureus among various clinical isolates. Methods: All the consecutive, non-duplicative Staphylococcus aureus isolates collected during the year 2020 were subjected to the disk diffusion method to evaluate the antimicrobial susceptibility pattern and were stocked. Mupirocin susceptibility for all stocked Staphylococcus aureus was detected by Minimal inhibitory concentration (MIC) determination by Epsilometer test (E-test). Results: The total number of Staphylococcus aureus was 52. The maximum number of Staphylococcus aureus was isolated from pus sample 40 (76.9%). Among the 52 isolates, 26 (50%) were found to be methicillin-resistant Staphylococcus aureus (MRSA). All the isolates were susceptible to tetracycline (100%), vancomycin (100%), teicoplanin (100%), and linezolid (100%). By E-test, the overall prevalence of mupirocin resistance was 63.5%. Low-level Mupirocin resistance (MupRL) of 8-256 µg/ml was 59.6% and high-level mupirocin resistance (MupRH) of ≥512 µg/ml was 3.9%. Conclusion: The present study shows a high prevalence of mupirocin resistance (63.5%) which is a serious concern. Therefore, indiscriminate use of topical mupirocin in carriers is not advisable. It may be recommended only in case of an outbreak of skin and soft tissue infection attributed to Staphylococcus aureus.

MICROBIAL PROFILE OF ULCERATIVE KERATITIS AT TERTIARY LEVEL HOSPITAL

Background: Keratitis is the term applied for inammations of the cornea. Ulcerative keratitis is a common potentially sight threatening ocular infection that may be caused by bacteria, fungi, viruses or parasites. Corneal ulcer is an ocular emergency that requires prompt management to ensure the best visual outcome for the patient. Otherwise, it can result in scarring and blindness. Aim and objectives: To study Microbial causes and to identify risk factors, and corelation of clinical features of ulcerative keratitis with etiological agents Materials and methods: Total 325 corneal ulcer cases were studied. Corneal scrapings were collected and subjected for examination by Gram's stain, 10% KOH, bacterial and fungal culture. Antibiotic susceptibility of the bacterial pathogens was performed by Kirby Bauer disc diffusion method as per CLSI guidelines with various groups of antibiotics. MIC for vancomycin were determined for study isolates by Epsilometer test. Results: Totally 325 infectious corneal ulcers were studied in detail. Aetiological agents were isolated in 115 (35.38%) cases. Majority of the isolates were fungal agents (44.18%), belonging to the Aspergillus (21.05%), Fusarium (14.47%). Bacterial corneal ulcer was less common (25.49%). The predominant bacterial pathogen isolated was Staphylococcus epidermidis, followed by Pseudomonas aeruginosa. no Acanthamoeba were identied. The sensitivity of potassium hydroxide staining was almost 100% in culture-proven fungal cases. Trauma is the leading cause for the corneal ulcers. Majority of the bacterial isolates were susceptible to amikacin. Conclusion: Ulcerative keratitis being a sight threatening disorder, early suspicion, rational use of laboratory diagnostic procedures, identication of the causative organisms and timely institution of appropriate antimicrobial therapy based on the prevailing sensitivity pattern of the isolates could save the eye from this preventable cause of blindness

Clostridioides difficile in food and food products of animal origin in Assam, India

ObjectiveConsidering the paucity of information about food-associated Clostridioides difficile from India, a study was undertaken to establish the prevalence of C. difficile in a variety of foods of animal origin, together with molecular strain characterization and antimicrobial resistance. MethodsA total of 235 samples comprising raw meat and meat products, fish products, and milk and milk products were screened for C. difficile. Toxin genes and other parts of PaLoc were amplified in isolated strains. The resistance pattern towards commonly used antimicrobial agents was studied by the Epsilometric test. ResultsC. difficile was isolated from 17(7.23%) different food samples of animal origin, including toxigenic (6) and non-toxigenic (11) isolates. In four toxigenic strains, the tcdA gene could not be detected under used conditions (tcdA-tcdB+). However, all strains had binary toxin-associated genes (cdtA and cdtB). The antimicrobial resistance was highest in non-toxigenic C. difficile isolates in food of animal origin. ConclusionMeat, meat products and dry fish, but not milk and milk products were contaminated with C. difficile. Contamination rates were low with diverse toxin profiles and antibiotic resistance patterns among the C. difficile strains.