There was a high prevalence of CR-GNB among septicemia patients, emphasizing the need for strict infection control measures to prevent their spread, and the need for strict infection control measures to prevent their spread.
Abstract
Aims
This study aimed to assess the antibiogram patterns of CR-GNB and to characterize carbapenemase-encoding genes among isolates obtained from patients with sepsis.
Methods
A total of 3,746 blood culture samples were collected from patients with suspected septicemia and samples were processed using the BACTEC blood culture system, and all positive cultures were sub-cultured onto blood agar and MacConkey agar plates for isolation. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK 2 compact system following CLSI guidelines. Detection of antimicrobial resistance genes was carried out by PCR using gene-specific primers.
Results
Of 3,746 blood cultures, 873 (23.3%) were positive, yielding 577 (66.1%) Gram-negative isolates. Among these, 212 (24.3%) were CR-GNB, predominantly A. baumannii (41.5%), and K. pneumoniae (21.2%). MIC of meropenem among CR-GNB isolates ranged from >128 µg/mL to <1024 µg/ml. Overall, 47.2% of isolates were inhibited at 624µg/mL, followed by 38.2% at 312 µg/mL, and 12.7% at 156 µg/ml. In CR-A. baumannii, blaOXA-23 and blaNDM were detected in 71.6% and 62.5% of isolates, respectively. blaNDM was also present in K. pneumoniae (43.8%), and E. coli (40.7%). .
Conclusion
There was a high prevalence of CR-GNB among septicemia patients, emphasizing the need for strict infection control measures to prevent their spread.
Background: Recently worldwide, carbapenem-resistant Klebsiella pneumoniae (CRKP) infection has attracted a lot of attention because of the scarcity of effective drugs and the severity of the illness as well as the high death rate. This study was conducted to assess the antimicrobial susceptibility profiles and the molecular identification of CRKP isolates that were obtained from patients with lower respiratory tract infection (LRTI) at a tertiary care hospital in Sylhet, Bangladesh.
Methods: This cross-sectional study was conducted in the Department of Microbiology at Sylhet MAG Osmani Medical College, Sylhet, from July 2021 to June 2022. A total of 153 sputum samples were collected from adult patients (≥18 years) clinically diagnosed with LRTIs. Data were analyzed using SPSS version 26.
Result: Among 153 sputum samples from LRTI patients, 66.0% showed bacterial growth, with Klebsiella pneumoniae accounting for 20.9% of isolates. The mean age was 52.43±17.12 years with male predominance (69.3%). Of the Klebsiella pneumoniae isolates, 25.0% were carbapenem-resistant (CRKP), among which 75.0% produced carbapenemase and 50.0% harbored the KPC gene. Overall isolates showed high resistance to cephalosporins (up to 81.2%) and moderate sensitivity to carbapenems (around 72–75%) and amikacin (56.2%). CRKP isolates demonstrated marked multidrug resistance, with high resistance to most antibiotics, including carbapenems (75.0%).
Conclusion: In conclusion, one in every fourth KP isolate was CRKP, which highlighted the need for careful prescription of carbapenems for the therapy of infectious diseases with ESBL-producing KP. Among different genes conferring resistance to carbapenems, only the blaKPC gene was investigated in this study.
S. Chowdhury, Swarna Paul, Fouzia Ahmed Chowdhury et al.· International Journal of Res...· 0 citations
Background: Infections of the bloodstream and sepsis are significant causes of morbidity and mortality, especially when complicated by multidrug resistance. Molecular diagnosis represents a tool for rapid identification of causative organisms with subsequent optimization of antimicrobial therapy; however, conventional blood culture still plays a critical role as a reference method for microbial identification and susceptibility testing. Methods: The study included 110 bloodstream isolates obtained from patients with suspected bacteremia and sepsis. Conventional blood culture was used for organism identification, incubation time analysis, and antibiogram testing, while multiplex PCR was used to screen for the most prevalent resistance determinants, namely NDM, OXA-48, KPC, VIM, mecA, and VanA/VanB genes. Bloodstream and non-bloodstream isolates from selected cases of sepsis were compared. Results: Klebsiella pneumoniae: 27 (24.5%), Staphylococcus aureus13 (11.8%), Escherichia coli8 (7.3%), Enterococcus faecium (7; 6.4%), Acinetobacter baumannii (8;7.3%), Enterococcus faecalis (6; 5.5%), and Pseudomonas aeruginosa (6; 5.5%) were the most prevalent species isolated from blood. The majority of cultures became positive within 20 hours from seeding, with 24 out of 97 (24.7%) positive between 0 and 10 hours and 55 out of 97 (56.7%) positive between 11 and 20 hours. The most prevalent resistance determinants were NDM, NDM+OXA-48, mecA, and VanA/VanB. Susceptibility testing revealed that carbapenems were largely ineffective against K.pneumoniae, while aztreonam/avibactam, tigecycline, fosfomycin, linezolid, vancomycin, and teicoplanin showed good activity against several strains of bacteria. Conclusion: The present findings demonstrate the potential utility of multiplex PCR as a rapid assay for detection of multidrug-resistant bloodstream pathogens and early optimization of antimicrobial treatment. At the same time, conventional blood culture remains an indispensable tool fo
Ruparna Kayal, B. Chaudhuri, P. Guchhait et al.· East African Scholars Journa...· 0 citations
Background: Salmonella species are important public health pathogens associated with bloodstream infections, particularly in settings where sanitation and healthcare access may be limited.
Aims: This study evaluated the antibiotic susceptibility pattern of Salmonella spp. isolated from patients’ blood specimens at Federal Medical Centre, Umuahia.
Methodology: A total of 470 whole-blood samples were collected from 470 patients and cultured. Suspected organisms were recovered from 88 samples (18.7%). Seventy-four suspected samples were sub-cultured onto selective media, including Xylose Lysine Deoxycholate agar, Salmonella-Shigella agar and MacConkey agar. Positive bacterial growth was obtained from 22 samples (29.7%), while 66 samples (75.0%) were negative after sub-culture. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion method, and the results were interpreted in relation to the tested isolates and reported inhibition-zone patterns within the hospital.
Results: Higher susceptibility was observed with cefuroxime, ceftriaxone and ciprofloxacin. Azithromycin and nalidixic acid showed lower susceptibility, while ampicillin, amoxicillin-clavulanate and chloramphenicol showed moderate activity. Gentamicin and tetracycline showed resistance among the isolates tested. None of the isolates was reported as multidrug resistant.
Conclusion: The findings indicate the need for continued blood culture surveillance and antimicrobial susceptibility testing to support the management of patients with Salmonella infections in the study setting.
Precious Nnedimma Sabastine-Nkeonadi, E. O. Onwuchekwa, U. K. Chukwu et al.· South Asian Journal of Resea...· 0 citations
BACKGROUND/AIMS
Acinetobacter baumannii is an opportunistic gram-negative pathogen and an increasingly important cause of hospital-acquired infections, particularly in intensive care units. Its remarkable ability to rapidly acquire resistance mechanisms, especially against carbapenems, represents a major public health concern. This study aimed to investigate the molecular detection and characterization of OXA-type carbapenemase genes in A. baumannii isolates collected from various clinical sources in Baghdad, Iraq.
METHODS
Between March and July 2025, 36 non-repetitive A. baumannii isolates were obtained from patients with different infections. Identification was performed using standard biochemical tests, CHROMagar Acinetobacter, and the VITEK 2 system and was confirmed by PCR amplification of the intrinsic blaOXA-51 gene. Antimicrobial susceptibility testing was conducted according to CLSI guidelines. The prevalence of blaOXA-23, blaOXA-24, blaOXA-51, and blaOXA-58 genes was determined by PCR. Selected PCR products were sequenced and subjected to phylogenetic analysis.
RESULTS
Extensive antimicrobial resistance was observed among the isolates, particularly to carbapenems, with resistance rates of 83.3% for imipenem and 72.2% for meropenem. High resistance rates were also detected for fluoroquinolones and aminoglycosides, whereas colistin and tigecycline retained comparatively greater activity. PCR screening revealed prevalence rates of 100% for blaOXA-51, 86.1% for blaOXA-23, 69.4% for blaOXA-24, and 47.2% for blaOXA-58. Multiple blaOXA genes were detected in more than half of the isolates, suggesting horizontal gene transfer and local clonal expansion. Phylogenetic analysis demonstrated high similarity between local isolates and international reference strains, supporting the widespread dissemination of resistance determinants. Several nucleotide substitutions were identified within the blaOXA-23 and blaOXA-24 genes.
CONCLUSION
The findings indicate that blaOXA-23 is the predominant contributor to carbapenem resistance among A. baumannii isolates in Baghdad, while blaOXA-24 and blaOXA-58 are also increasingly prevalent. The observed resistance patterns and phylogenetic relationships underscore the importance of continuous molecular surveillance, antimicrobial stewardship, and effective infection control measures to limit the spread of multidrug-resistant A. baumannii. These data contribute valuable regional information to the global understanding of antimicrobial resistance epidemiology.
A. A. Abdulhassan, Hiba Hazim Hamid, Sara Mahdi Al-Lami et al.· Cellular Physiology and Bioc...· 0 citations
Background: Klebsiella pneumoniae is a critical contributor to both community- and hospital-acquired infections, with rising multidrug resistance (MDR) posing serious therapeutic challenges.
Objective: This study assessed the prevalence of K. pneumoniae and its antimicrobial susceptibility patterns among clinical specimens collected at Chittagong Medical College, Bangladesh.
Methodology: This cross-sectional study was conducted from July 2022 to June 2023 in Chittagong Medical College, Chattogram. A total of 320 clinical specimens (urine, wound swabs, sputum, blood) from inpatients and outpatients were subjected to culture and sensitivity. Conventional microbiological identification was confirmed by 16S rRNA PCR. Antimicrobial susceptibility (excluding colistin) was tested via the Modified Kirby–Bauer disk diffusion method (CLSI 2022). Colistin resistance was assessed using the colistin agar test, applying CLSI breakpoints.
Results: Overall culture positivity was 63.4% (203/320). Klebsiella pneumoniae was confirmed in 16.9% (54/320) of samples, most commonly isolated from sputum (51.4%), followed by wound swabs (17.1%), urine (11.8%), and blood (6.5%). Among the 54 Klebsiella pneumoniae isolates, resistance rates were highest against amoxiclav (94.4%), with lower resistance observed for aminoglycosides (amikacin, 24.1%) and meropenem (31.5%). Colistin resistance was detected in 12.9% (7/54) of Klebsiella pneumoniae isolates.
Conclusion: The prominence of Klebsiella pneumoniae and its variable degree of resistance to multiple antibiotics, underscores an urgent need for enhanced antimicrobial stewardship, accurate diagnostics, and robust surveillance in Bangladesh.
Bangladesh Journal of Medical Microbiology, January 2026;20 (1):3-9
D. Chowdhury, Sahed Uddin, Pompy Dey et al.· Bangladesh Journal of Medica...· 0 citations
INTRODUCTION: Antimicrobial resistance is a growing global threat, with carbapenem-resistant
A. baumannii (CRAB) identified by World Health Organisation (WHO) as a top-priority pathogen. In
Rwanda, data on resistance patterns and underlying genetic determinants in A. baumannii remains
limited. This study aims to assess phenotypic resistance profile and detect key resistance genes to
support infection prevention and control (IPC) and antimicrobial stewardship interventions.
METHODS: A cross-sectional study was conducted from February to July 2025.Acinetobacter
baumannii isolates were identified and tested for antimicrobial susceptibility using the disk
diffusion method. Polymerase chain reaction (PCR) was used to detect selected resistance genes.
Data on patient demographics, sample types, and hospital wards were collected and analysed.
RESULTS: Of 1746 clinical isolates, 3.2% (n=56) were confirmed Acinetobacter baumannnii. Most
isolates were recovered from male Intensive Care Unit (ICU) patients aged 19–40. All isolates
showed 100% resistance to key beta-lactams, high resistance to ciprofloxacin with 87.0%,
gentamicin 78.3%, while complete susceptibility to imipenem at 100% was observed. Resistance
genes; blaOXA-23 and blaCTX-M were detected in 60.9% and 52.2% of isolates respectively,
confirming the genetic basis for carbapenem and ESBL resistance.
CONCLUSION: The study revealed a significant burden of multidrug-resistant Acinetobacter
baumannii infections, particularly among ICU patients. The high resistance of blaOXA-23 and blaCTX-M highlights the complexity of managing these infections and
underscores the need for strengthened IPC measures, routine molecular surveillance, and
targeted AMS strategies.
J. Uwimana, L. Mutesa, A. Ishimwe et al.· Rwanda medical journal· 0 citations
