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Showing 3 results for Multiple Drug Resistance
Antibiotic resistance profile of Acinetobacter baumannii isolates identified from blood cultures
Zaid Faris Hasan , Umut Safiye Şay Coşkun,
Volume 18, Issue 4 (7-2024)
Abstract
Background: Acinetobacter baumannii (A. baumannii) has emerged as the predominant etiological agent responsible for bloodstream infections among hospitalized patients. The objective of this study was to evaluate antibiotic resistance in A. baumannii isolates identified from blood cultures.
Methods: A retrospective cohort evaluation was conducted on 117 A. baumannii isolates obtained from blood cultures collected between 2018 and 2019 at the Microbiology Laboratory of Tokat Gaziosmanpaşa University Hospital (Türkiye). The blood culture samples were incubated using the BACT-ALERT 3D system (bioMérieux, Durham, NC, USA). Microorganism identification and antibiotic susceptibility testing were performed using the VITEK 2 (bioMérieux, France) automated system.
Results: Of the 117 samples, 59.8% were obtained from males and 40.2% from females. A total of 90.6% of blood culture samples were collected from the intensive care unit, and 88.9% of isolates were identified as multidrug-resistant (MDR). The highest resistance was observed against meropenem (99.1%), while the lowest resistance was noted for colistin (17.1%) and tigecycline (27.3%). Resistance to amikacin was 74.4%, while resistance levels to gentamicin, tobramycin, cefoxitin, and cefotaxime were within the range of 80–90%. Resistance to imipenem, amoxicillin/clavulanic acid, ampicillin/sulbactam, ceftazidime, cefepime, ciprofloxacin, levofloxacin, meropenem, and ertapenem exceeded 90%.
Conclusion: The increasing number of MDR A. baumannii isolates poses a significant threat to all hospitalized patients. However, colistin and tigecycline remain preferable options for the treatment of MDR A. baumannii infections. Considering the increasing prevalence of MDR A. baumannii isolates, periodic analysis of epidemiological data in healthcare centers is important for managing resistance to colistin and tigecycline.
 

Comparative evaluation of in vitro activity of tigecycline using the disc diffusion method and the VITEK-2 COMPACT in clinical isolates at a tertiary care cancer center
Sujata Lall , Vivek Bhat, Sanjay Biswas, Navin Khattry ,
Volume 18, Issue 4 (7-2024)
Abstract
Background: Tigecycline susceptibility testing and reporting remain enigmatic due to the lack of established guidelines. Disc diffusion, as a method of performing susceptibility testing, is more widely accepted worldwide due to its ease of use. Limited published literature is available from India on the utility of this method, especially in a cancer care setting. Hence, this study was conducted to evaluate the performance characteristics of disc diffusion by comparing its results with those of the VITEK-2 COMPACT, considering the latter as the standard.
Methods: Disc diffusion was performed using Kirby-Bauer’s method on Mueller-Hinton agar with a HiMedia 15 mcg TGC disc, following FDA and EUCAST breakpoints. According to CLSI criteria, disc diffusion breakpoints can be considered acceptable when categorical agreement is ≥ 90%, the very major error is ≤ 1.5%, and the major error is ≤ 3%.
Results: Using Cohen’s kappa coefficient, the kappa value was 0.328, with a p-value of <0.05. The agreement percentage observed was 60.84%. Two strains reported as resistant by VITEK-2 COMPACT were misclassified as sensitive by disc diffusion, resulting in a very major error rate of 0.76%. A major error rate of 9.5% and a minor error rate of 27.7% were noted, as 25 strains reported as susceptible were identified as resistant.
Conclusion: Since poor agreement was observed, exceeding the acceptable performance rate, the disc diffusion method was unacceptable according to CLSI criteria. There is a gap in uniformity and a lack of streamlined, harmonized TST, which might become an alarming cause for concern.
 

Resistance Investigation of Uropathogenic Escherichia coli strains isolated from urinary tract infections in the north of Iran
Zahra Askari, Zeynab Mirzapour, Seyedeh Tooba Shafighi, Reyhaneh Ghorbanpour,
Volume 19, Issue 1 (4-2025)
Abstract
Background and objectives: Urinary tract infection (UTI) caused by Uropathogenic Escherichia coli (UPEC) is a worldwide health problem. Virulence factors (VFs) expressed by UPEC strains promote the pathogenicity of bacteria in the urinary tract. Treatment of the infection is often difficult due to the high antimicrobial resistance of E. coli. This study aimed to determine VFs and the antibiotic susceptibility pattern of isolated UPEC strains in the north of Iran.

Methods: 105 urine samples were collected from females with UTIs, in north of Iran, Rasht. The samples were cultured on EMB agar and MacConkey agar. The plates were incubated at 37°C for 24 h and the pure isolates were identified using Gram-stains and standard biochemical tests. The presence of six VF genes including papC, sfa/foc, fimH, afa, ibeA and neuC were identified by polymerase chain reaction (PCR) in UPEC strains and verified by direct sequencing. Antibiotic susceptibility test (AST) was performed by disk diffusion method based on the Clinical and Laboratory Standards Institute (CLSI) guidelines.
Results: 65.71% isolates were identified as E. coli. The most frequent virulence gene was fimH (100%) and the least one was afa (1.44%).  The highest and the lowest antibiotic resistance rates were observed against Cephazolin (66.66%), and Gentamicin (24.63%), respectively. Indeed, the prevalence of multiple drug resistance (MDR) was determined as 73.91%.
Conclusion: Our study highlighted the importance of local monitoring in UPEC isolates due to the high genetic mutation capacity of the pathogen, environmental and patient properties to recommend the best strategies against UTIs.
 
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