Microbial drug resistance最新文献

Acinetobacter baumannii is a highly antibiotic-resistant pathogen causing nosocomial severe life-threatening infections, especially in critically ill patients. Capsular polysaccharide is a major virulence factor of A. baumannii both in vitro and in vivo. In this study, 220 isolates were collected in the hospital. The prevalent capsular types of A. baumannii were determined using polymerase chain reaction, and the clinical characteristics of infections were analyzed. The virulence of these strains was determined by serum-killing resistance, biofilm formation, and Galleria mellonella survival assays. Twenty-eight isolates (12.7%) carried KL2, and 22 isolates (10%) carried the types KL10, KL14, KL22, and KL52. Compared with non-KL2 (KL10, KL14, KL22, and KL52) isolates, KL2 isolates had significantly higher resistance to all antimicrobials except tigecycline, cefoperazone-sulbactam, or colistin. Seventy-five percent of KL2 A. baumannii and 72.7% of non-KL2 were highly virulent using a G. mellonella model. Biofilm formation was significantly different between the KL2 and non-KL2 groups. The biofilm production of non-KL2 A. baumannii was significantly stronger than that of KL2 A. baumannii. These findings highlight the role of KL2 as a powerful factor for drug resistance and virulence of A. baumannii.

The global dissemination of extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli has been considered a critical issue within a One Health framework. The aim of this study was to perform a genomic investigation of an ESBL-producing E. coli strain belonging to the globally spread sequence type/clonal complex ST90/CC23, isolated from gastrointestinal tract of a dog, in Brazil. Besides CTX-M-15 ESBL, this E. coli isolate carried mutations conferring resistance to human and veterinary fluoroquinolones (GyrA [Ser83Leu, Asp87Asn], ParC [Ser80Ile] and ParE [Ser458Ala]), and resistance determinants to disinfectants and pesticides. Noteworthy, phylogenomic analysis revealed that this multidrug E. coli strain clustered with ST90 lineages isolated from human, dog, and livestock in Brazil. The phylogenetic tree also revealed that this E. coli strain shares a common ancestor with isolates from the United States, Russia, Germany, and China, highlighting the potential global spreading of this clone. In summary, we report genomic data of CTX-M-15-positive E.coli ST90 colonizing a pet. Colonization of companion animals by critical resistant pathogens highlights the need for close monitoring to better understand the epidemiology and genetic factors contributing for successful adaptation of global clones at the human-animal interface.

This study aimed to identify variation in the minimum biocidal concentration (MBC) over time, comparing three commercial super-oxidized solutions with different chemical compositions. In the bactericidal assay, the following bacteria were tested: Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), and for each ATCC, one wild-type strain was used. In vitro experiments were performed in triplicate at 0, 60, and 120 days of follow up. A commercial formulation based on sodium and chloride ions (SCSS) was tested using a standard accelerated aging protocol. Data were analyzed with the Friedman and Wilcoxon signed-rank tests. The results showed that super-oxidized solution bases of 20 ppm of sodium (SSS) had a significant change in MBC at 120 days (p < 0.001), whereas SCSS remained stable during the same period (p = 0.18). However, after accelerated aging treatment, the MBC of SCSS increased (p < 0.001). With our proposed approach, the two SSS showed MBC variation at 120 days, whereas SCSS showed stability over time, similar to chlorhexidine, but lost its bactericidal properties after accelerated aging treatment.

There is a scarcity of data regarding the antimicrobial susceptibility testing profiles of nontuberculous mycobacterial (NTM) in Israel and other Middle Eastern countries. We aimed to describe the antimicrobial susceptibility profiles of NTM in Israel. A total of 410 clinical isolates of NTM, identified to the species level using matrix-assisted laser desorption ionization-time of flight mass spectrometry or hsp65 gene sequencing, were included. Minimum inhibitory concentrations for slowly growing mycobacteria (SGM) and rapidly growing mycobacteria (RGM) for 12 and 11 drugs were determined using the Sensititre SLOMYCOI and RAPMYCOI broth microdilution plates, respectively. Mycobacterium avium complex (MAC) was the most frequently isolated species (n = 148; 36%), followed by Mycobacterium simiae (n = 93; 23%), Mycobacterium abscessus group (n = 62; 15%), Mycobacterium kansasii (n = 27; 7%), and Mycobacterium fortuitum (n = 22; 5%) accounting together for 86% of isolates. The most active agents against SGM were amikacin (98%/85%/100%) and clarithromycin (97%/99%/100%), followed by moxifloxacin (25%/10%/100%) and linezolid (3%/6%/100%) for MAC, M. simiae, and M. kansasii, respectively. For RGM, the most active agents were amikacin (98%/100%/88%) followed by linezolid (48%/80%/100%) and clarithromycin (39%/28%/94%) for M. abscessus group, M. fortuitum, and M. chelonae, respectively. These findings can assist in guiding the treatment of NTM infections.

In this study, we aimed to characterize drug-resistant strains by whole-genome sequencing (WGS), to describe the spreading lineages and the history of transmission. Drug susceptibility testing was performed by 96-well broth microdilution plates. The genomic DNA was extracted and purified; libraries were prepared and run on the Illumina NextSeq500 System. Among 82 isolates, 21 tuberculosis (TB) isolates (25.6%) were drug resistant, including 10 MDR and 4 pre-extensively drug-resistant (XDR)-TB. The mutation Ser315Thr in the katG gene was confirmed in 15 isolates. In rpoB, Ser450Leu and His445Asp mutations were the most common. Asp94Asn and Ala90Val mutations were reported in gyrA. The LAM family, the most TB drug resistant, was widely predominant in the north and the T sublineage in the south of the country. This study provides the first insight on TB drug resistance using WGS in Algeria and clearly describes the first pre-XDR-TB cases and lineage distribution across the country.

In this study, we report the carbapenemase-encoding genes and colistin resistance in Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa in the second year of the COVID-19 pandemic. Clinical isolates included carbapenem-resistant K. pneumoniae, carbapenem-resistant E. coli, carbapenem-resistant A. baumannii, and carbapenem-resistant P. aeruginosa. Carbapenemase-encoding genes were detected by PCR. Carbapenem-resistant K. pneumoniae and carbapenem-resistant E. coli isolates were analyzed using the Rapid Polymyxin NP assay. mcr genes were screened by PCR. Pulsed-field gel electrophoresis and whole-genome sequencing were performed on representative isolates. A total of 80 carbapenem-resistant E. coli, 103 carbapenem-resistant K. pneumoniae, 284 carbapenem-resistant A. baumannii, and 129 carbapenem-resistant P. aeruginosa isolates were recovered. All carbapenem-resistant E. coli and carbapenem-resistant K. pneumoniae isolates were included for further analysis. A selection of carbapenem-resistant A. baumannii and carbapenem-resistant P. aeruginosa strains was further analyzed (86 carbapenem-resistant A. baumannii and 82 carbapenem-resistant P. aeruginosa). Among carbapenem-resistant K. pneumoniae and carbapenem-resistant E. coli isolates, the most frequent gene was bla_NDM (86/103 [83.5%] and 72/80 [90%], respectively). For carbapenem-resistant A. baumannii, the most frequently detected gene was bla_OXA-40 (52/86, 60.5%), and for carbapenem-resistant P. aeruginosa, was bla_VIM (19/82, 23.2%). For carbapenem-resistant A. baumannii, five indistinguishable pulsotypes were detected. Circulation of K. pneumoniae New Delhi metallo-β-lactamase (NDM) and E. coli NDM was detected in Mexico. High virulence sequence types (STs), such as K. pneumoniae ST307, E. coli ST167, P. aeruginosa ST111, and A. baumannii ST2, were detected. Among K. pneumoniae isolates, 18/101 (17.8%) were positive for the Polymyxin NP test (two, 11.0% positive for the mcr-1 gene, and one, 5.6% with disruption of the mgrB gene). All E. coli isolates were negative for the Polymyxin NP test. In conclusion, K. pneumoniae NDM and E. coli NDM were detected in Mexico, with the circulation of highly virulent STs. These results are relevant in clinical practice to guide antibiotic therapies considering the molecular mechanisms of resistance to carbapenems.

Background: This study aimed to determine the epidemiology of gram-negative bacteria (GNB) isolated in the newborn intensive care unit (NICU) population, to assess their antibiotic susceptibility patterns and possible associated risk factors. Methods: All neonates admitted to the NICU of Abderrezak-Bouhara hospital (Skikda, Algeria) with a clinical diagnosis of neonatal infections from March to May 2019 were included in the study. The extended-spectrum β-lactamase (ESBLs), plasmidic cephalosporinase (pAmpC), and carbapenemases genes were screened by polymerase chain reaction (PCR) and sequencing. PCR amplification of oprD among carbapenem-resistant Pseudomonas aeruginosa isolates was also performed. The clonal relatedness of the ESBLs isolates was studied using multilocus sequence typing (MLST). Results: Among 148 clinical specimens, 36 (24.3%) GNB strains were isolated from urine (n = 22), wound (n = 8), stool (n = 3), and blood (n = 3) samples. The bacterial species identified were Escherichia coli (n = 13), Klebsiella pneumoniae (n = 5), Enterobacter cloacae (n = 3), Serratia marcescens (n = 3), Salmonella spp. (n = 3), Proteus mirabilis (n = 1), P. aeruginosa (n = 5), and Acinetobacter baumannii (n = 3). PCR and sequencing showed that eleven Enterobacterales isolates harbored the bla_CTX-M-15 gene, two E. coli isolates harbored the bla_CMY-2 gene, and three A. baumannii isolates harbored both bla_OXA-23 and bla_OXA-51 genes. Also, five strains of P. aeruginosa were found to harbor mutations in the oprD gene. MLST showed that the K. pneumoniae strains belonged to ST13 and ST189, E. coli belonged to ST69, and E. cloacae belonged to ST214. Different risk factors that could predict positive GNB cultures were found, including female sex, Apgar score <8 at 5 min of life, enteral nutrition, antibiotic use, and extended length of hospitalization. Conclusion: Our study highlights the importance of determining the epidemiology of pathogens causing neonatal infections, their sequence types (ST), and their antibiotic susceptibility patterns to address rapidly a correct antibiotic treatment regimen.