Emergence and spread of resistant and biofilm-forming Acinetobacter baumannii in critically ill COVID-19 patients.

The COVID-19 pandemic has raised concerns beyond the viral infection itself. Bacterial co-infections, particularly those involving Acinetobacter baumannii, have become a significant worry in critically ill COVID-19 patients. A. baumannii is an opportunistic pathogen that can cause nosocomial infections, especially in patients with compromised immune systems. This study investigated 36 A. baumannii isolates obtained from COVID-19 patients during a concurrent outbreak. The isolates were collected over two years through routine medical requests sent to the Clinical Microbiology laboratory. Identification of the strains was confirmed through biochemical tests, the Phoenix BD® Automated Microbiology System, and MALDI-TOF Mass Spectrometry. The study assessed the antimicrobial sensitivity of the isolates, with a specific focus on resistance to the beta-lactam group as well as aminoglycosides. The presence of specific antibiotic resistance genes (blaOXA-23, -24, -51 and -58, blaKPC, blaSHV, blaIMP, blaVIM, aac(6')-Ib, ant(3″)-Ia, and aph(3')-Ia) was investigated using PCR and Sanger DNA sequencing. Biofilm-forming capabilities of the isolates were also evaluated. The findings revealed diverse resistance profiles, with a high prevalence of resistant strains, including resistance to carbapenems. Genetic analysis suggested potential clonal spread of certain strains within the hospital setting. Moreover, a significant proportion of the isolates demonstrated strong biofilm-forming abilities, which can enhance persistence and antibiotic resistance. In conclusion, this study highlights the need for vigilant monitoring and targeted interventions to address bacterial co-infections in COVID-19 patients. The diversity in resistance patterns, potential clonal spread, and robust biofilm-forming abilities among A. baumannii isolates underscore the importance of addressing this issue to better manage and treat critically ill COVID-19 patients.

Occurrence and Diversity of Intra- and Interhospital Drug-Resistant and Biofilm-Forming Acinetobacter baumannii and Pseudomonas aeruginosa.

Acinetobacter baumannii and Pseudomonas aeruginosa are the most relevant Gram-negative bacteria associated with hospital and opportunistic infections. This study aimed to evaluate the dynamics of drug-resistant A. baumannii and P. aeruginosa and biofilm formers from two public hospitals in northeastern Brazil. One hundred isolates (35 from A. baumannii and 65 from P. aeruginosa) were identified using the automated Vitek®2 Compact method (bioMérieux) and confirmed using the MALDI-TOF (MS) mass spectrometry technique. Molecular experiments were performed by polymerase chain reaction (PCR) to detect the frequency of blaKPC, blaIMP, blaVIM, and blaSHV genes. The biofilm formation potential was evaluated using crystal violet in Luria Bertani Miller and trypticase soy broth culture media under the following conditions: at standard concentration, one quarter (25%) of the standard concentration and supplemented with 1% glucose. In addition, the genetic diversity of the isolates was verified by the ERIC-PCR technique. Isolates presented distinct resistance profiles with a high level of beta-lactam resistance. The highest index of genes detected was blaKPC (60%), followed by blaSHV (39%), blaVIM (8%), and blaIMP (1%). All the isolates were sensitive to the polymyxins tested and formed biofilms at different intensities. Twelve clones of A. baumannii and eight of P. aeruginosa were identified, of which few were indicative of intra- and interhospital dissemination. This study reveals the dispersion dynamics of these isolates in the hospital environment. The results demonstrate the importance of monitoring programs to combat the spread of these pathogens.