Changing Paradigms in Antibiotic Resistance in Salmonella Species with Focus on Fluoroquinolone Resistance: A 5-Year Retrospective Study of Enteric Fever in a Tertiary Care Hospital in Kolkata, India

Abstract

Enteric fever, a potentially fatal multisystem disease that is caused by Salmonella enterica serovar Typhi and Paratyphi, poses a significant risk in low- and middle-income countries. A retrospective study to understand the prevalence and evolving patterns of antibiotic resistance in Salmonella Typhi and Paratyphi was undertaken from June 2017 to June 2022. A total of 4051 blood samples were collected from patients attending inpatient and outpatient departments of the School of Tropical Medicine (Kolkata, India) hospital. Blood samples were cultured, and culture positive samples were further processed for identification using conventional and automated systems. Antibiotic susceptibility test was performed using both the Kirby-Bauer disc diffusion method and VITEK2 (bioMerieux). Forty-five (1.1%) Salmonella species were isolated among the number of total (n = 4051) samples that were tested. Out of the 45 Salmonella isolates, 35 were Salmonella Typhi (77.77%) and 10 were Salmonella Paratyphi A (22.23%). We found pronounced fluoroquinolone resistance of 100% in the recent years (2019–2022) in both of the S. Typhi and S. Paratyphi A isolates. We found that 1 Salmonella Typhi and 2 Salmonella Paratyphi A isolates were resistant against multiple antibiotics (cefixime, ceftriaxone, ciprofloxacin and nalidixic acid), and 1 multidrug-resistant (MDR) Salmonella Paratyphi A isolate was found in a recent study year (2020) and it showed resistance against different classes of antibiotics (cephalosporins, fluoroquinolones and carbapenems). There was no resistance that was detected to the 3rd generation cephalosporins in the final years of the study. The emergence of Salmonella isolates that are resistant to multiple antibiotics poses a serious health problem. The antimicrobial resistance patterns that were detected in the study thus warrant further studies to understand the antibiotic susceptibility and resistance pattern of Salmonella against the major classes of antibiotics.

Antibiotic Resistance and Plasmid Replicon Types of Non-Typhoidal Salmonella Serovars Isolated From Food Animals and Humans in Lagos, Nigeria

“…The apparent difference in level susceptibility may be due the source of the isolates, since clinical isolates are known to be more resistant to fluoroquinones. 17 Plasmids are wide spread among Salmonella serovars where they mediate both virulence and resistance to antibiotics. 8 Plasmids are major players in the horizontal transfer of AMR determinants in Salmonella.…”

Antibiotic Resistance among Salmonella Isolates - A Five-year Trend

“…In our study, the positivity of blood culture for Salmonella enterica varied from 0.7% to 1.3% while in a study conducted by Biswas et al, the positivity varied from 0.4% to 1.7% (2017-2022). 15 In concordance with other studies, S. Typhi was found to be the leading isolate in comparison to S. Paratyphi A. 16,17 In our study, males (64%) were predominantly infected as compared to females (36%), which is corroborated by a study conducted by Biswas et al, in which 66.6% of the enteric fever patients were males, 15 whereas in contrast, only 47.7% males were involved in a study conducted in South India 18 .…”

“…4,5,19 In the present study, resistance to ciprofloxacin during 2018-2022 varied from 56.8% to 87.3% and from 99% to 100% in S. Typhi and S. Paratyphi A, respectively. Various authors reported resistance to ciprofloxacin in S. Typhi isolates (13.6%, 20 67.3%, 11 68.5%, 21 80%, 15 and 100% 22 ) and S. Paratyphi A (11%, 22 82.6%, 21 90%, 15 and 97.6% 11 ). A report from the United Kingdom has also shown an increase in the incidence of S. enterica serovar Typhi isolates with decreased ciprofloxacin susceptibility (from 0.9% to 33%) in a span of just 8 years.…”

“…30 In our study, S. Typhi isolates showed resistance to ampicillin (0%-6.2%), cotrimoxazole (0.0%) and chloramphenicol (0.8%-2.1%). Various authors reported resistance to ampicillin (34.1%-100%, 20 0.0%, 15,22 and 23.1% 21 ), cotrimoxazole (0%-9.7%, 20 0.0%, 15,22 24.1% 21 ) and chloramphenicol (0%, 15 2.4%, 20 11.0%, 22 and 25.6% 21 ).…”

The Benefits and Challenges of Antibiotics–Non-Steroidal Anti-Inflammatory Drugs Non-Covalent Reaction

“…This was associated with more capillary lung lesions and bilateral disease, which required more prolonged treatment [125]. Also, more than half of S. aureus strains tested were MDR, showing resistance to fluoroquinolones [126][127][128]. Efforts have been made to improve the fluoroquinolones' potency, for example, by conjugate biofilm formation, a major virulence factor of Pseudomonas auroginosa that causes antibiotic resistance [129].…”