Carbapenem-resistant Klebsiella pneumoniae (CPKP) infections seriously threaten global public health. The main objective of this study was to assess the in-vitro synergistic activity of ceftazidime–avibactam (CZA) in combination with colistin (COL), amikacin (AK), gentamicin (GEN), and fosfomycin (FOS) against CPKP isolates. The secondary goal was to determine the antibiotic susceptibility performance of BD Phoenix. OXA-48 (49.1%) was the predominant carbapenemase, followed by KPC (29.1%). We used the broth microdilution (BMD) method to determine the minimum inhibitory concentrations (MICs) of CZA, COL, AK, and GEN. Meanwhile, the MICs of FOS were determined by the agar dilution (AD) method. To examine the antibacterial activity of CZA, we conducted a checkerboard assay (CBA) with COL, AK, GEN, and FOS against CRKP isolates. We randomly selected three strains and performed synergy testing via time-kill assay (TKA). CRKP isolates were 89.1% susceptible to CZA, 16.4% to COL, 21.8% to GEN, and 29.1% to AK using BMD, 47.3% to FOS by AD. The most synergistic effects were observed in the combination of CZA-COL (78.2%) and CZA-FOS (63.6%). Given the limited therapeutic options for treating severe CRKP infections, combining CZA with COL and FOS may enhance in-vitro activity against clinical CRKP isolates.

This study aims to investigate trends in bloodstream infections and their antimicrobial susceptibility profiles over 12 years in our hospital. This retrospective study was carried out in the Bursa Uludag University Hospital, Turkey, during 2008–2019. Blood cultures from patients were performed using BACTEC System. Isolates were identified with Phoenix System until 2018 and “matrix-assisted laser desorption ionization time-of-flight mass spectrometry” (MALDI-TOF MS) in 2019. Antibiotic susceptibility testing was performed with Phoenix System. Patient data came from the BD EpiCenter™ data management system. Escherichia coli was found to be the most common Gram-negative (11.6%), and coagulase-negative staphylococci were the most common Gram-positive (10.1%) monomicrobial growth. Overall, there was a significant increase in rates of extended-spectrum β-lactamase positive E. coli (p = 0.014) and Klebsiella pneumonia (p < 0.001), carbapenem-resistant E. coli (p < 0.001), and K. pneumoniae (p < 0.001) and colistin-resistant K. pneumoniae (p < 0.001) and Acinetobacter baumannii (p < 0.001) over 12 years. Carbapenem and colistin resistance has increased dramatically in recent years. We believe that regular monitoring of the distribution of pathogens and antibiotic susceptibility profiles, especially in intensive care units, can contribute to evidence for the increase in resistant microorganisms and help prevent their spread with antimicrobial stewardship and infection control policies.

Background: We aimed to compare the performance of carbapenemase classification in carbapenem-resistant Klebsiella pneumoniae (CRKP) obtained using the BD Phoenix CPO Detect panel (CPO panel) and Cepheid Xpert Carba-R assays. We analyzed 55 CRKP strains from clinical specimens collected between November 2020 and November 2022. The CPO panel was used to detect both antibiotic susceptibility and phenotypic carbapenemase classes, while Xpert Carba-R was employed to identify KPC, NDM, VIM, OXA-48, and IMP genes. Due to the limited availability of molecular kits, we arbitrarily selected 55 isolates, identified as carbapenemase-producing according to the CPO panel and with meropenem minimum inhibitory concentration values > 8 mg/L. Results: According to the Xpert Carba-R assay, 16 of the 55 isolates (29.1%) were categorised as Ambler Class A (11 of which matched CPO panel Class A identification); three isolates (5.5%) were identified as Class B and 27 isolates (49.1%) as Class D (in both cases consistent with CPO panel B and D classifications). A further eight isolates (14.5%) exhibited multiple carbapenemase enzymes and were designated as dual-carbapenemase producers, while one isolate (1.8%) was identified as a non-carbapenemase-producer. The CPO panel demonstrated positive and negative percent agreements of 100% and 85.7% for Ambler Class A, 100% and 100% for Class B, and 96.4% and 100% for Class D carbapenemase detection, respectively. Conclusion: While the CPO panel’s phenotypic performance was satisfactory in detecting Class B and D carbapenemases, additional confirmatory testing may be necessary for Class A carbapenemases as part of routine laboratory procedures.

The aim of this study was to evaluate the combination treatments with intravenous fosfomycin for carbapenem-resistant Klebsiella pneumoniae infections in a tertiary-care center.