Background: A variety of clinically important pathogens have developed multidrug resistance (MDR), which threatens global public health. This study aimed to determine the incidence, patterns, and trends of MDR of gram-negative bacterial isolates in clinical specimens in the Tamale Teaching Hospital, Ghana. Methods: This retrospective study analyzed gram-negative bacterial isolates and antimicrobial susceptibility test (AST) results of patients who visited the Tamale Teaching Hospital laboratory between 2017 and 2019. Results: A total of 2,779 gram-negative bacterial isolates and their phenotypic AST results were analyzed. From these, 1,297 gram-negative bacteria (46.7%) were isolated from urine samples, while the rest were isolated from sputum (20.9%), wound (14.3%), and swabs (11.7%) samples, etc. Escherichia coli (23.8%) was the most common gram-negative pathogen found predominantly in the urine samples (33.2%). All gram-negative bacteria isolated between 2017 and 2019 showed high MDR. Klebsiella pneumoniae gradually increased its MDR from 84.0% in 2017, 89.5% in 2018, to 95.1% in 2019. On the other hand, the MDR rates in Pseudomonas aeruginosa were approximately 65.8%, varying from 59.5% in 2017 to 78.7% in 2019. Among tested antimicrobials, amikacin was the most effective. Resistance to amikacin in Enterobacter spp., E. coli, and K. pneumoniae in vitro were 16.2%, 11.8%, and 17.7%, respectively. Conclusion: The study has shown that the high levels of MDR in gram-negative bacteria isolated may be associated with the infections recorded at the Tamale Teaching Hospital. The major gram-negative pathogens isolated have resistance to penicillins, cephalosporins, and fluoroquinolones. Aminoglycosides can offer high antibiotic activity to overcome gramnegative bacterial resistance. Further studies will be needed to decide policy direction on infection prevention and control, and antimicrobial stewardship programs.

Background: Environmental sanitation plays a significant role on the prevalence of enteropathogenic bacteria. This study aimed to determine the trends in the prevalence and antimicrobial resistance profiles of enteropathogenic bacteria from 2011 to 2019. Methods: A retrospective analysis was performed using data from stool cultures of Salmonella spp., Shigella spp., Plesiomonas shigelloides, Yersinia spp., Vibrio spp., and Campylobacter spp. Samples were obtained between 2011 and 2019 from Severance Hospital. Antimicrobial susceptibility profile was determined using the disk diffusion method for nontyphoidal Salmonella (NTS) and Campylobacter spp., following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: The number of specimens obtained for stool culture increased significantly from 13,412 during the period of 1969–1978, to 48,476 over the past nine years (2011–2019), whereas the ratio of positive specimens decreased significantly from 1,732 (12.9%) to 449 (0.9%). The proportion of samples positive for Salmonella Typhi decreased from 472 (93.6%, 1969–1978) to 4 (1.5%, 2011–2019), whereas the proportion of NTS increased from 14 (2.8%, 1969–1978) to 261 (96.7%, 2011–2019). Among all the enteropathogenic bacteria isolated, Shigella spp. accounted for 60.0% (1,039) isolates from 1969 to 1978, but only 1.6% (7) from 2011 to 2019. Campylobacter was the second most prevalent enteropathogenic bacteria, accounting for 29.4% isolates (132). Among the NTS strains isolated from 2016 to 2019, their susceptibility rates to ampicillin and sulfamethoxazole-trimethoprim were 51.1% and 85.2%, respectively. Additionally, the susceptibility rate of Campylobacter to ciprofloxacin was 15.8%. Conclusion: The prevalence of Salmonella Typhi and Shigella spp. significantly decreased, whereas those of NTS and Campylobacter spp. increased. Therefore, continuous monitoring of ciprofloxacin-resistant Campylobacter spp. is of vital importance.

(1) Background: Linezolid plays an important role in the treatment of invasive infections caused by vancomycin-resistant enterococci after its introduction to clinical practice. However, a detailed examination of linezolid-nonsusceptible enterococci (LNSE) is required. In this study, we attempted to analyze the mechanisms of LNSE strains isolated from a tertiary care hospital. (2) Methods: From 2019 to 2020, 18 Enterococcus faecalis, 14 E. faecium, and 2 E. gallinarum clinical isolates were collected at Severance Hospital. Agar dilution was performed to evaluate precise linezolid minimum inhibitory concentrations (MICs). Short-read whole-genome sequencing (WGS) was used to analyze resistance determinants. (3) Results: The presence of the optrA gene was likely the primary resistance mechanism in these three species, typically demonstrating a MIC value of 8 μg/mL. The co-existence of the cfr(D) and poxtA2 gene was the second major mechanism, primarily predicting a phenotype showing intermediate susceptibility to linezolid. G2576U mutation on 23S rRNA was only found in E. faecium; it mediated the most significant increase in linezolid MIC. (4) Conclusion: This is the first report examining poxtA2–cfr(D) co-harboring clinical enterococcal isolates in Korea and demonstrating the poxtA EF9F6-harboring clinical E. gallinarum strain worldwide. The comparison with resistance-gene-containing fragments in the isolates obtained from different countries and different sources demonstrated the spread of linezolid-resistance genes and suggested the possibility of foodborne transmission.