BACKGROUND: Carbapenem-resistant strains of Pseudomonas aeruginosa (CRPA) have become a major healthcare concern in many countries, against which anti-infective strategies are limited and which require adequate infection control interventions. Knowing the different modes of transmission of CRPA in intensive care units (ICUs) would be helpful to adapt the means of prevention.
METHODS: The aim of this retrospective case-control study was conducted between 01/01/2017 and 02/28/2022 to identify the risk factors for the acquisition of CRPA in ICUs.
RESULTS: During the study period, 147 patients were included (49 cases and 98 controls). Among the 49 patients, 31 (63%) acquired CRPA in clusters and 18 (37%) sporadically. An univariate analysis showed that five variables were associated with CRPA acquisition including (i) prior antibiotic prescriptions, (ii) admission to rooms 203 and 207, (iii) severity of illness at admission, and (iv) use of mechanical ventilation. Multivariate analysis identified three factors of CRPA acquisition including admission to room 203 (OR = 29.5 [3.52-247.09]), previous antibiotic therapy (OR = 3.44 [1.02 - 11.76]) and severity of condition at admission (OR = 1.02 [1 - 1.04]).
CONCLUSIONS: Our study suggests the role of a contaminated environment in the acquisition of CRPA in the ICU, along with antibiotic use.

We describe four cases of a novel carbapenem-resistant Pseudomonas aeruginosa ST179 clone carrying the blaKPC-2 or blaKPC-35 gene together with blaIMP-16, imported from Peru to Spain and isolated from leukemia patients. All isolates were multidrug-resistant but remained susceptible to fosfomycin, cefiderocol, and colistin. Whole-genome sequencing revealed that blaKPC-2 and blaKPC-35 were located in an IncP6 plasmid, whereas blaIMP-16 was in a chromosomal type 1 integron. This study highlights the global threat of multidrug-resistant P. aeruginosa clones and underscores the importance of monitoring and early detection of emerging resistance mechanisms to guide appropriate treatment strategies. The importation and spread of such clones emphasize the urgent need to implement strict infection control measures to prevent the dissemination of carbapenem-resistant bacteria.
OBJECTIVE: This is the first documented case of a Pseudomonas aeruginosa ST179 strain carrying the blaKPC-35 gene, and it represents the first report of a P. aeruginosa co-harboring blaIMP-16 and either blaKPC-2 or blaKPC-35, which wre imported from Peru to Spain, highlighting a threat due to the capacity of spreading carbapenem-resistance via plasmid conjugation.

OBJECTIVE: The aim was to analyse the clinical and economic impact of carbapenemase-producing Enterobacterales (CPE) infections.
METHODS: Case-control study. Adult patients with CPE infections were considered cases, while those with non-CPE infections were controls. Matching criteria were age (± 5 years), sex, source of infection and microorganism (ratio 1:2). Primary outcome was 30-day mortality. Secondary outcomes were 90-day mortality, clinical failure, hospitalisation costs and resource consumption.
RESULTS: 246 patients (82 cases and 164 controls) were included. Klebsiella pneumoniae OXA-48 was the most common microorganism causing CPE infections. CPE cases had more prior comorbidities (p = 0.007), septic shock (p = 0.003), and were more likely to receive inappropriate empirical and definitive antibiotic treatment (both p < 0.001). Multivariate analysis identified septic shock and inappropriate empirical treatment as independent predictors for 7-day and end-of-treatment clinical failure, whereas Charlson Index and septic shock were associated with 30- and 90-day mortality. CPE infection was independently associated with early clinical failure (OR 2.18, 95% CI, 1.03-4.59), but not with end-of-treatment clinical failure or 30- or 90-day mortality. In terms of resource consumption, hospitalisation costs for CPE were double those of the non-CPE group. CPE cases had longer hospital stay (p < 0.001), required more long-term care facilities (p < 0.001) and outpatient parenteral antibiotic therapy (p = 0.007).
CONCLUSIONS: The CPE group was associated with worse clinical outcomes, but this was mainly due to a higher comorbidity burden, more severe illness, and more frequent inappropriate antibiotic treatment rather than resistance patterns as such. However, the CPE group consumed more healthcare resources and incurred higher costs.

BACKGROUND: Nationwide research on the association between carbapenem-resistant Enterobacterales (CREs) and antibiotic use is limited.
METHODS: This nested case-control study analyzed Korean National Health Insurance claims data from April 2017 to April 2019. Based on the occurrence of CRE, hospitalized patients aged ≥ 18 years were classified into CRE (cases) and control groups. Propensity scores based on age, sex, modified Charlson comorbidity score, insurance type, long-term care facility, intensive care unit stay, and acquisition of vancomycin-resistant Enterococci were used to match the case and control groups (1:3).
RESULTS: After matching, the study included 6,476 participants (1,619 cases and 4,857 controls). Multivariable logistic regression analysis revealed that the utilization of broad-spectrum antibiotics, such as piperacillin/tazobactam (adjusted odds ratio [aOR], 2.178; 95% confidence interval [CI], 1.829-2.594), third/fourth generation cephalosporins (aOR, 1.764; 95% CI, 1.514-2.056), and carbapenems (aOR, 1.775; 95% CI, 1.454-2.165), as well as the presence of comorbidities (diabetes [aOR, 1.237; 95% CI, 1.061-1.443], hemiplegia or paraplegia [aOR, 1.370; 95% CI, 1.119-1.679], kidney disease [aOR, 1.312; 95% CI, 1.105-1.559], and liver disease [aOR, 1.431; 95% CI, 1.073-1.908]), were significantly associated with the development of CRE. Additionally, the CRE group had higher mortality (8.33 vs. 3.32 incidence rate per 100 person-months, P < 0.001) and a total cost of healthcare utilization per person-month (15,325,491 ± 23,587,378 vs. 5,263,373 ± 14,070,118 KRW, P < 0.001) than the control group.
CONCLUSIONS: The utilization of broad-spectrum antibiotics and the presence of comorbidities are associated with increasing development of CRE. This study emphasizes the importance of antimicrobial stewardship in reducing broad-spectrum antibiotic use and CRE disease burden in Korea.

Infections caused by extensively drug-resistant Pseudomonas aeruginosa are difficult to treat due to limited effective treatment options. In this issue, a patient with a corneal infection caused by a Verona integron-encoded metallo-β-lactamase (VIM)- and Guiana extended-spectrum β-lactamase (GES)-coproducing P. aeruginosa strain associated with the recent artificial tears-related outbreak in the United States is described. This resistance genotype/phenotype further compromises therapeutic options, and this report provides insights into diagnostic and treatment approaches for clinicians dealing with infections due to this highly resistant P. aeruginosa.

Salmonella enterica serovar Typhimurium is a gram-negative bacterium mainly involved in foodborne diseases. Several pathways of antimicrobial resistance have been recently identified in this strain. This article reports a case of a patient hospitalized in intensive care who underwent emergency trauma surgery. During his hospitalization, he developed a nosocomial bacteremia from a surgical wound infection. The cytobacteriological examination of the surgical site and the blood culture isolated Salmonella spp. susceptible to third-generation cephalosporins, resistant to ertapenem, and with decreased sensitivity to imipenem. The carbapenemase test was positive for blaOXA-48. The serotyping identified Salmonella enterica serovar Typhimurium. The patient\'s response to antibiotics was favorable.

Ralstonia spp. is an emerging, non-fermentative Gram-negative rod that demonstrates multidrug resistance. Herein, four cases of bloodstream infections (BSI) caused by R. mannitolilytica or R. pickettii are presented. All the cases had comorbidities that predisposed them to this opportunistic infection. The microbiological assessment showed carbapenemase genes carried out in two strains with minimal inhibitory concentrations > 32 μg/mL to imipenem and meropenem. Fluoroquinolones and trimethoprim-sulphamethoxazole were the most potent agents showing activity against 3/4 strains (75%), although treatment should be susceptibility-dependent for each strain. This case series highlights the possibility of co-infection by a rare organism during the COVID-19 pandemic and the importance of the readiness of diagnostic laboratories to support the diagnosis of uncommon pathogens.

This study investigated the mechanism of carbapenem resistance in an Enterobacter cloacae complex positive by the modified carbapenem inactivation method (mCIM) but negative by the Rosco Neo-Rapid Carb Kit, β CARBA, and conventional PCR for common carbapenemase genes (KPC, NDM, OXA-48, IMP, VIM, GES, and IMI/NMC). Using whole genome sequencing (WGS) data we confirmed the identification of Enterobacter asburiae (ST1639) and the presence of blaFRI-8 located on a 148kb IncFII(Yp) plasmid. This is the first occurrence of a clinical isolate harboring the FRI-8 carbapenemase and the second occurrence of FRI in Canada. This study highlights the need to use both WGS and phenotypic screening methods for detection of carbapenemase-producing strains if we consider the growing diversity of carbapenemases.

We report a Russian case of a 61-year-old male patient with confirmed COVID-19 infection who developed nosocomial pneumonia complicated by lung abscess associated with multi-drug-resistant isolates of Klebsiella pneumoniae and Acinetobacter baumannii, which could have been provoked due to the immunosuppressive therapy. We discuss the existing literature highlighting the issue of the prudent balance between benefits and risks when prescribing immunomodulators to hospitalized patients with COVID-19 due to the risk of difficult-to-treat nosocomial infections caused by MDR Gram-negative bacterial pathogens. Currently, there is evidence of a substantial positive effect of dexamethasone on the course of COVID-19 in patients requiring supplemental oxygen or anti-interleukin-6 drugs in individuals with prominent systemic inflammation. However, it seems that in real clinical practice, the proposed criteria for initiating treatment with immunomodulators are interpreted arbitrarily, and the doses of dexamethasone can significantly exceed those recommended.

Here we describe an unusual clinical presentation of infection due to Aeromonas hydrophila and underline the importance of a correct microbiological diagnosis for an adequate treatment. A 6-year-old patient with a history of craniotomy with duraplasty the week before consulted for fever and drainage of serosanguineous fluid from the surgical wound. The laboratory parameters were normal and the computed tomography scan showed no relevant changes. Lumbar puncture: leukocytes: 91/mm3; proteins: 89 mg/dL; glucose: 36 mg/dL. Treatment with vancomycin and ceftazidime was started. Cerebrospinal fluid culture: oxidase-positive, glucose-fermenting Gram-negative bacillus. Treatment was changed to meropenem. At 72 hours, using a diffusion method and Vitek 2, it was reported as Aeromonas hydrophila sensitive to trimethoprim-sulfamethoxazole, ciprofloxacin, cefotaxime, and meropenem. The Blue-Carba method was performed to detect carbapenemases; the result was positive. Treatment was changed to trimethoprimsulfamethoxazole. The patient completed 21 days of treatment with a favorable clinical course.
Se describe una presentación clínica inusual de infección por Aeromonas complejo hydrophila y se destaca la importancia del correcto diagnóstico microbiológico para adecuar el tratamiento. Paciente de 6 años consultó por fiebre y drenaje de líquido serohemático de herida quirúrgica por antecedente de craneotomía con duroplastia la semana previa. Laboratorio con parámetros normales y tomografía computada sin cambios relevantes. Punción lumbar: leucocitos 91/mm3, proteínas 89 mg/dl, glucosa 36 mg/dl. Comenzó tratamiento con vancomicina y ceftazidima. Cultivo de líquido cefalorraquídeo: bacilo gramnegativo, oxidasa positivo, fermentador de glucosa. Se rotó a meropenem. A las 72 horas, se informó, por método difusión y Vitek2, Aeromonas complejo hydrophila: sensible a trimetoprimasulfametoxazol, ciprofloxacina, cefotaxima y meropenem. Se realizó método Blue Carba para detección de carbapenemasas con resultado positivo. Se rotó a trimetoprima-sulfametoxazol. Completó 21 días de tratamiento con evolución clínica favorable.