Bacteria, Volume 2, Issue 4 (December 2023) – 4 articles

(1) Background: Given the widespread use of Alkalihalobacillus clausii (A. clausii) as a probiotic in recent decades and the detection of bacteremia cases in a group of patients, we sought to analyze cases of A. clausii bacteremia following oral probiotic use (2) Methods: A retrospective observational study was conducted at a private hospital in San Jose, Costa Rica. Cases of bacteremia caused by A. clausii confirmed by the microbiology laboratory were analyzed in patients who received oral treatment with this probiotic between January 2020 and January 2022. In addition, an isolate (HCB-AC2) was compared through whole genome sequencing to demonstrate the correlation of bacteremia and A. clausii. Possible vulnerability factors related to the development of this condition were determined. (3) Results: Four cases were identified in this hospital over 2 years. Genomic analysis of isolate HCB-AC2, using two different methods, showed identical results. This indicates that HCB-AC2 is genomically identical to ENTpro and the Enterogermina^® reference genome. The median age was 71 years, and all patients had some degree of immunosuppression. All patients met at least three sepsis criteria at the time of bacterial identification. Most patients were treated with vancomycin and levofloxacin. Three of the identified patients died. (4) Conclusion: A. clausii can be used as a probiotic, but caution is advised when used in immunosuppressed and elderly patients. These findings align with those reported in similar case studies. Full article

The presence of nontuberculous mycobacteria in biofilms on the surface of medical devices may affect the opportunistic pathogens that are common inhabitants of such biofilms. This study assessed the effect of Mycolicibacterium iranicum cell-free supernatants on biofilm formation and antibiotic susceptibility of Escherichia coli and Staphylococcus epidermidis differing in the anti-hemoglobin activity level. The cell-free supernatants have been shown to stimulate biofilm formation and also help reduce susceptibility of opportunistic pathogens to a number of antibiotics. Full article

Klebsiella pneumoniae, a Gram-negative pathogen, poses a significant threat as a cause of community- and hospital-acquired infections worldwide. The emergence of multidrug-resistant strains, particularly in nosocomial settings, has further complicated the management of these infections. This study aimed to investigate the culture identification and antibiogram of K. pneumoniae isolated from sputum samples collected in various districts in Mardan, Khyber Pakhtunkhwa, Pakistan. A total of 16 sputum samples were collected from patients at the Mardan Medical Complex. Standard microbiological techniques were employed to identify K. pneumoniae, and the antibiotic susceptibility testing was performed using the Kirby–Bauer disc diffusion method, following CLSI guidelines. Among the confirmed K. pneumoniae isolates, approximately 50% were found to be multidrug-resistant. The results indicated resistance to several antibiotics, including vancomycin (30 g), amikacin (30 g), chloramphenicol (30 g), amoxicillin (30 g), and ticarcillin (75 g), while being susceptible to meropenem (10 g), piperacillin (100 g), and tazobactam (110 g). A bioinformatics analysis was also conducted to gain deeper insights into the resistance patterns and potential clustering of isolates. This comprehensive study provides valuable information on the epidemiological trends and antimicrobial susceptibility profile of K. pneumoniae in the region. The findings of this study highlight the urgent need for antimicrobial stewardship programs to combat the rising challenge of antibiotic resistance. Understanding the resistance landscape of K. pneumoniae can guide healthcare professionals in selecting appropriate antibiotics and improving patient outcomes. These data can contribute to the formulation of local antibiotic policies and assist clinicians in making rational choices for antibiotic therapy. Full article

During meat processing, lactic acid bacteria (LAB) have to competitively adapt to the hostile environment produced by curing additives (CA). The objective of this study was to investigate the ability of Latilactobacillus curvatus CRL 705, a bioprotective strain of meat origin, to adapt to CA. A physiological and proteomic approach was performed. CRL 705 was grown in a chemically defined medium (CDM) containing specific concentrations of CA (NaCl, nitrite, sucrose, and ascorbic acid). The results showed minor differences in growth kinetics in the presence of CA. Glucose consumption, present in the CDM, and production of lactic acid and bacteriocins were not significantly affected. Proteomic analyses indicated that most of the identified proteins (36 out of 39) mainly related to carbohydrate metabolism (18%), posttranslational modifications (15.6%), energy production and conversion (11.1%), translation (11.1%), and nucleotide metabolism (8.9%) were underexpressed. In response to the studied CA, CRL 705 slowed down its general metabolism, achieving slight changes in physiological and proteomic parameters. The observed performance is another characteristic that extends the well-known competitive profile of CRL 705 as a meat starter and bioprotective culture. This is the first report dealing with the impact of CA on LAB proteomics. Full article