Bloodstream infection caused by KPC-producing Klebsiella pneumoniae resistant to ceftazidime/avibactam: epidemiology and genomic characterization

Objectives: The aim of this study was to evaluate the incidence of ceftazidime/avibactam resistance among Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-Kp) strains isolated from patients with bloodstream infection. Methods: We collected 120 carbapenemase producing Enterobacteriaceae (CPE) strains from unique patients hospitalized in two Italian hospitals between January 2018 to February 2019. Strains were phenotypically characterized for the type of carbapenemase production and susceptibility to ceftazidime/avibactam. Ceftazidime/avibactam-resistant strains were characterized by whole-genome sequencing. Results: During the study period, we characterized 105 (87.5%) KPC producers among a total of 120 CPE strains. Ceftazidime/avibactam resistance was found in three KPC-Kp strains isolated from patients with no history of previous ceftazidime/avibactam-based treatment. Of note, two out of three ceftazidime\u2013avibactam-resistant KPC-Kp were also resistant to meropenem/vaborbactam. Genomic characterization showed that a ceftazidime/avibactam-resistant KPC-Kp harboured a mixed population with D179Y mutated KPC-2, while the other two ceftazidime\u2013avibactam-resistant KPC-Kp possessed non-functional ompK35-ompK37 and mutated ompK36 porins associated with higher copy number of blaKPC gene. Conclusions: Our results showed that incidence of ceftazidime/avibactam resistance emerged in KCP-Kp strains independently from previous antimicrobial exposure. Resistance to ceftazidime/avibactam was associated with mutations within the blaKPC gene or porin deficiency associated with higher blaKPC copy number and is also related to the meropenem/vaborbactam resistance

Epidemiology and In Vitro Activity of Ceftazidime/Avibactam, Meropenem/Vaborbactam and Imipenem/Relebactam against KPC-Producing K. pneumoniae Collected from Bacteremic Patients, 2018 to 2020

The management of KPC-producing K. pneumoniae (KPC-Kp) in bloodstream infections (BSIs) represent a serious clinical challenge. In this study, the aim is to assess the incidence of resistance to novel β-lactams-β-lactamase inhibitor combinations (βL-βLICs), such as ceftazidime-avibactam (CAZ-AVI), meropenem-vaborbactam (MER-VAB) and imipenem-relebactam (IMI-REL), in KPC-Kp strains collected during a three-year period from patients with bacteremia. KPC-Kp strains resistant to βL-βLICs were selected for whole-genome sequencing. A total of 133 K. pneumoniae strains were isolated, and KPC-Kp strains were the most represented (87.2%). In 2018, resistance to CAZ-AVI and MER-VAB was 6.5% and 14.5%, respectively. In 2019, KPC-Kp resistance to CAZ-AVI and MER-VAB remained at low levels, with values of 12.9% and 3.2%, respectively. During 2020, CAZ-AVI resistance was detected in 2/23 of KPC-Kp strains (8.7%). IMI-REL was the most active βL-βLIC, inhibiting >98% of the isolates, while CAZ-AVI and MER-VAB inhibited 87-93% and 85-97% of the KPC producers, respectively. Correlations between genotypic traits and resistance to βL-βLICs showed that KPC-Kp strains resistant to CAZ-AVI harbored a mutation within the blaKPC-3 gene, while all KPC-Kp strains resistant to CAZ-AVI, MER-VAB and/or IMI-REL carried the blaKPC-3 gene. Moreover, genetic analysis of porin genes showed that 14/16 of KPC-Kp resistant isolates possessed a truncated OmpK35 and glycine (G) and aspartic acid (D) insertions at positions 134-135 within OmpK36, whereas 2/16 displayed truncated OmpK35 and OmpK36 porins. Novel βL-βLICs are promising agents against KPC-Kp infections; however, the emergence of resistance to these agents highlights the need for continuous surveillance and application of enhanced antimicrobial stewardship

Analysis and characterization of mouse monoclonal antibodies reactive to Chikungunya virus (CHIKV)

occurring in 1984). However, plague has made an astonishing comeback in the last decade. Methods: n/a. Results: After a silence of 50 years, an outbreak of bubonic plague suddenly occurred close to Oran in Algeria, in June 2003. Eighteen bubonic cases were identified, and Yersinia pestis was isolated from 6 patients. In July 2008, a new cluster was reported among nomads 300 km south of the first one. Four members of one family were affected and one died. The bacillus was isolated from one patient. No epidemiological association was identified between the two events. On June 2009, 25 years after the last occurrence in the country, Libya reported five confirmed cases of bubonic plague in the Tobruk area. Y. pestis was isolated from three patients. In all these cases, further local ecological investigations confirmed the existence of a natural focus The re-emergence of human plague in the region is not without international consequences. Two of the last concerned natural foci are close to an international port which raises the question of the potential exportation of infected rodents. Cross-border tensions, between ''plague countries'' and ''plague-free countries'' have been observed although the foci's limits are unknown as any systematic ecological investigation and surveillance is lacking. Additionally, the potential weaponization of Y.pestis together with international political tensions feed a recurrent interest in plague in North Africa. False rumors of alleged military laboratory accidents or terrorist acts are routinely mentioned, although events could be first explained by the natural history of the disease. Conclusion: In this context, and although the number of human cases has been very limited so far, the first priorities are to establish appropriate ecological surveillance and agree on a common plague control strategy for the region

Chikungunya virus (CHIKV) infection: Analytical performance of real-time NASBA assay

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A descriptive pharmacokinetic/pharmacodynamic analysis of continuous infusion ceftazidime-avibactam for treating DTR gram-negative infections in a case series of critically ill patients undergoing continuous veno-venous haemodiafiltration (CVVHDF)

Purpose: To explore pharmacokinetic/pharmacodynamic (PK/PD) profile of continuous infusion (CI) ceftazidime-avibactam for treating difficult-to-treat resistant Gram-negative (DTR-GN) infections in critical patients undergoing continuous venovenous haemodiafiltration (CVVHDF). Materials and methods: Patients treated with CI ceftazidime-avibactam for DTR-GN infections during CVVHDF were retrospectively assessed. Ceftazidime and avibactam concentrations were measured at steady-state and the free fraction (fCss) was calculated. Total clearance (CLtot) of both agents were calculated and the impact of CVVHDF intensity was assessed by linear regression. The joint PK/PD target of ceftazidime-avibactam was defined as optimal when both fCss/MIC≥4 for ceftazidime and fCss/CT > 1 for avibactam were achieved. Relationship between ceftazidime-avibactam PK/PD targets and microbiological outcome was assessed. Results: Eight patients with DTR-GN infections were retrieved. Median fCss were 84.5 (73.7–87.7 mg/L) for ceftazidime and 24.8 mg/L (20.7–25.8 mg/L) for avibactam. Median CLtot was 2.39 L/h (2.05–2.96 L/h) for ceftazidime and 2.56 L/h (2.12–2.98 L/h) for avibactam. Median CVVHDF dose was 38.6 mL/h/kg (35.9–40.0 mL/kg/h). CLtot were linearly correlated with CVVHDF dose (r = 0.53;p = 0.03, and r = 0.64;p = 0.006, respectively). The joint PK/PD targets were optimal granting microbiological eradication in all the assessable cases. Conclusion: CI administration of 1.25–2.5 g q8h ceftazidime-avibactam may allow prompt attainment and maintenance of optimal joint PK/PD targets during high-intensity CVVHDF

Comparative genomic and phylogenetic analysis of the first usutu virus isolate from a human patient presenting with neurological symptoms.

Usutu virus (USUV) is a mosquito-borne flavivirus, belonging to the Japanese encephalitis antigenic complex, that circulates among mosquitoes and birds. We describe and analyze the complete genome sequence of the first USUV strain isolated from an immunocompromised patient with neuroinvasive disease. This USUV isolate showed an overall nucleotide identity of 99% and 96%, respectively, with the genomes of isolates from Europe and Africa. Comparison of the human USUV complete polyprotein sequence with bird-derived strains, showed two unique amino acid substitutions. In particular, one substitution (S595G) was situated in the DIII domain of the viral Envelope protein that is recognized by flavivirus neutralizing antibodies. An additional amino acid substitution (D3425E) was identified in the RNA-dependent RNA polymerase (RdRp) domain of the NS5 protein. This substitution is remarkable since E3425 is highly conserved among the other USUV isolates that were not associated with human infection. However, a similar substitution was observed in Japanese encephalitis and in West Nile viruses isolated from humans. Phylogenetic analysis of the human USUV strain revealed a close relationship with an Italian strain isolated in 2009. Analysis of synonymous nucleotide substitutions (SNSs) among the different USUV genomes showed a specific evolutionary divergence among different countries. In addition, 15 SNSs were identified as unique in the human isolate. We also identified four specific nucleotide substitutions in the 59 and 39 untranslated regions (UTRs) in the human isolate that were not present in the other USUV sequences. Our analyses provide the basis for further experimental studies aimed at defining the effective role of these mutations in the USUV genome, their potential role in the development of viral variants pathogenic for humans and their evolution and dispersal out of Africa

Complete Genome Sequence of a Klebsiella pneumoniae Strain Carrying Novel Variant blaKPC-203, Cross-Resistant to Ceftazidime/Avibactam and Cefiderocol, but Susceptible to Carbapenems, Isolated in Italy, 2023

Background: Klebsiella pneumoniae is a concerning pathogen, responsible for hospital-associated outbreaks. Multi drug resistant (MDR) strains are especially hard to treat. We conducted whole-genome sequencing on a MDR K. pneumoniae strain in order to identify genomic features potentially linked to its phenotype. Methods: DNA sequencing was performed on the Illumina iSeq 100 platform. Genome assembly was carried out with SPAdes. The genome was annotated with RASTtk. Typing was performed with MLST and Kaptive. Antibiotic resistance genes were detected with AMRFinderPlus and Abricate, and further verified with BLAST. Results: The strain exhibited resistance to ceftazidime/avibactam and cefiderocol, but remained susceptible to carbapenems. The strain belonged to sequence type ST101, serotype O1:K17. The analysis of antibiotic resistance genes indicated that the strain carried a novel KPC variant, designated as KPC-203, featuring a EL deletion at amino acid position 166-167, within the Omega-loop, and a nine-amino-acid insertion (LAVYTRAPM) at position 259. Sequence alterations were found in porin genes ompK35 and ompK36. Unlike molecular testing, which was able to detect the KPC-203 variant, all phenotypic carbapenemase detection methods achieved negative results. Conclusions: KPC-203, a novel KPC variant, showed a sequence modification in a cephalosporin resistance-associated hotspot. Interestingly, such alterations typically correlate with the restoration of carbapenem susceptibility. We hypothesize that KPC-203 likely led to resistance to ceftazidime/avibactam and cefiderocol, while maintaining susceptibility to carbapenems

Serological update of the Chikungunya epidemic outbreak in Italy

Serological update of the Chikungunya epidemic outbreak in Italy P. Gaibani1,∗, A. Pierro1, F. CAVRINI2, G. Rossini 3, M.P. Landini 3, C. Manisera4, V. Sambri5 1 S.Orsola-Malpighi, Bologna, Italy 2 S. Orsola-Malpighi Hospital, BOLOGNA, Italy 3 S.Orsola-Malpighi Hospital, section of Microbiology, BOLOGNA, Italy 4 S.Orsola-Malpighi Hospital, Microbiology, Bologna, Italy 5 University of Bologna, Bologna, Ital

Imported cases of Chikungunya and Dengue fever in Emilia Romagna region, Italy

Imported cases of Chikungunya and Dengue fever in Emilia Romagna region, Italy F. Cavrini 1,∗, P. Gaibani2, C. Manisera3, A. Pierro4, G. Rossini 5, M.P. Landini 5, V. Sambri6 1 S. Orsola-Malpighi Hospital, BOLOGNA, Italy 2 S.Orsola-Malpighi Hospital, Section of Microbiology, BOLOGNA, Italy 3 S.Orsola-Malpighi Hospital, Section of Microbiology, BOLOGNA, Italy 4 S.Orsola-Malpighi, Bologna, Italy 5 S.Orsola-Malpighi Hospital, section of Microbiology, BOLOGNA, Italy 6 University of Bologna, Bologna, Ital

Serodiagnosis of visceral leishmaniasis in northeastern italy: Evaluation of seven serological tests

This study compares the performance of seven assays, including two ELISA (Leishmania ELISA IgG + IgM, Vircell Microbiologists; Leishmania infantum IgG ELISA, NovaTec), three rK39-based immunochromatographic tests (rK39-ICTs) (Leishmania Dipstick Rapydtest, Apacor; On Site Leishmania IgG/IgM Combo Rapid Test, CTK Biotech; LEISHMANIA Strip quick Test, Cypress Diagnostic), one indirect immunofluorescent antibody test (IFAT) (Leishmania-Spot IF, BioM\ue9rieux), and one western blot (WB) (Leishmania WESTERN BLOT IgG, LDBio Diagnostics) for serodiagnosis of visceral leishmaniasis (VL). Serum samples from 27 VL patients living in northeastern Italy were analyzed, as well as the serum samples from 50 individuals in whom VL diagnosis was excluded. The WB and the IFAT had 96% sensitivity, followed by the ELISA (63% and 74%, respectively). The rK39-ICT exhibited the worst performance among the serological tests, with sensitivities ranging from 52% to 70%. By combining selected ELISA/ICT, the sensitivity of VL detection reached 89%. IFAT and WB outperformed ELISA and rK39-ICT by possessing optimal sensitivity, but their high cost and complexity of execution would not allow their employment as screening tests. In conclusion, the combination of easy-to-perform tests, such as ICT and ELISA, could improve sensitivity in the serodiagnosis of Mediterranean VL