Secondary Klebsiella pneumoniae infection in patients with COVID-19: A systematic review.

This study aims to investigate the development of secondary bacterial infection and risk factors associated with it in critical COVID-19 patients, and to identify the most common pathogen groups in them. All the cohort studies were retrieved from Scopus, Google Scholar, Web of Science, and MEDLINE from the inception of COVID-19 to 2022 for the following keywords: 'Klebsiella" AND "COVID-19". The most common comorbidities among the patients with COVID-19 were respiratory disease (33.62%), obesity (28.99%), and heart disease or cardiovascular disease (16.31%). We report 42.91% rate of Klebsiella spp co-infection in ICU admission patients, mostly related to K. pneumonia (26.81%), K. aerogenes (9.4%), and K. oxytoca (6.7%). The overall incidence of bacterial infection in hospitalized COVID-19 patients is estimated at 15.5% and in 32.5% of cases of co-infection patients deceased. The threat of carbapenem-resistant K. pneumoniae infections in patients with COVID-19 is imminent, therefore rational antibiotic therapy based on antibiotic sensitivity test should be implemented.

Upstream region of OprD mutations in imipenem-resistant and imipenem-sensitive Pseudomonas isolates.

The current study was aimed at investigating the prevalence of the mutations upstream of the oprD coding region and its promoters among imipenem-resistant and sensitive Pseudomonas aeruginosa isolated from educational hospitals in Yazd City, Iran. All isolates were identified by the conventional biochemical tests. Then, the antibiotic resistance of these isolates was determined using the disk diffusion method according to the CLSI guidelines. Also, the E.test was performed to determine the minimum inhibitory concentrations (MIC) of imipenem. The mutations of this gene were recognized by the amplification of this region and subsequently sequenced. Sequencing of the genomic region upstream of oprD these regions were done in the 29 clinical strains. Statistical analysis was done by the statistical software SPSS-18. Seventy (77.7%) of isolates had MIC ≥ 16 and were resistant to imipenem. Mutations of the upstream of the oprD gene and its promoters were seen in 25 (86.2%) isolates and 4 isolates had no mutation. One isolate had a base substitution A→Cat nt 25 in the coding region and this isolate had a point mutation leading to an amino acid change at positions 9 (I→L). Our study results indicated that none of the strains had mutation in Shine-Dalgarno and the point mutations were the most common mutations upstream of the oprD coding region among P. aeruginosa isolates. Mutations were observed in imipenem-resistant isolates and it seems this mechanism is effective in resistance of isolates to imipenem and this confirmed that the indiscriminate use of antibiotic should be controlled.