Prevalence of multidrug resistance Salmonella species isolated from clinical specimens at University of Gondar comprehensive specialized hospital Northwest Ethiopia: A retrospective study

BACKGROUND

Multidrug resistance Salmonellosis remains an important public health problem globally. The disease is among the leading causes of morbidity and mortality in developing countries, but there have been limited recent studies about the prevalence, antimicrobial resistance, and multidrug resistance patterns of Salmonella isolates from various clinical specimens.

OBJECTIVE

Aimed to assess the prevalence, antimicrobial resistance, and multidrug resistance patterns of Salmonella isolates from clinical specimens at the University of Gondar Comprehensive Specialised Hospital, northwestern Ethiopia.

METHOD

A retrospective hospital-based cross-sectional study was conducted to determine the prevalence, antimicrobial resistance, and multidrug resistance patterns of isolated from all clinical specimens at the University of Gondar Salmonella Comprehensive Specialised Hospital from June 1st, 2017 to June 3rd, 2022. A total of 26,154 data points were collected using a checklist of records of laboratory registration. Clinical specimens were collected, inoculated, and incubated for about a week with visual inspection for growth and gram staining. The isolates were grown on MacConkey agar and Xylose Lysine Deoxycholate agar. Pure colonies were identified with a conventional biochemical test, and those unidentified at the species level were further identified by the analytical profile index-20E. Then, antimicrobial susceptibility was determined by the Kirby-Bauer disc diffusion technique. The multidrug resistance Salmonella isolates was identified using the criteria set by Magiorakos. Finally, the data was cleaned and checked for completeness and then entered into SPSS version 26 for analysis. Then the results were displayed using tables and figures.

RESULTS

Of the total 26,154 Salmonella suspected clinical samples, 41 (0.16%) Salmonella species were isolated. Most of the Salmonella isolates, 19 (46.3%), were in the age group of less than 18 years, followed by the age group of 19-44 years, 11 (26.8%). In this study, S. enterica subsp. arizonae accounts for the highest 21 (51%), followed by S. paratyphi A 9 (22%). Of the Salmonella isolates, S. typhi were highly resistant to ampicillin (100%), followed by tetracycline and trimethoprim-sulfamethoxazole, each accounting for 83.3%. Furthermore, S. paratyphi A was resistant to ampicillin (100%), tetracycline (88.9%), and chloramphenicol (88.9%). The overall multi-drug resistance prevalence was 22 (53.7%; 95% CI: 39.7-61). Accordingly, S. paratyphi A was 100% multidrug-resistant, followed by S. typhi (66.6%).

CONCLUSION

A low prevalence of Salmonella species was observed in the past six years. Moreover, most S. typhi and S. paratyphi strains in the study area were found to be resistant to routinely recommended antibiotics like ciprofloxacin and ceftriaxone, compared to what was reported earlier. In addition, all isolates of S. paratyphi A and the majority of S. typhi were multidrug resistant. Therefore, health professionals should consider antimicrobial susceptibility tests and use antibiotics with caution for Salmonellosis management.

Salmonella Typhi and Salmonella Paratyphi prevalence, antimicrobial susceptibility profile and factors associated with enteric fever infection in Bahir Dar, Ethiopia

Enteric fever (EF) is caused by Salmonella enterica serovars Typhi (S. Typhi) and Paratyphi (S. Paratyphi) causing significant health problems in developing countries including Ethiopia. Thus present study aimed to determine prevalence and antimicrobial resistance profile of S. Typhi and S. Paratyphi among EF suspected patients at Felege-Hiwot comprehensive specialized hospital, Bahir Dar, Ethiopia. Hospital based cross-sectional study was conducted from March-to-May 2020. Totally, 150 patients were included conveniently. Data were collected using questionnaires by face-to-face interview. Concurrently, venous blood and stool specimens were collected and processed following standard bacteriological technique. Antimicrobial susceptibility test (AST) was performed by disc diffusion method. Logistic regression was performed to identify factors associated with EF infection. The study indicated 5.3% EF prevalence where S. Typhi accounted 75%. S. Typhi and S. Paratyphi isolates were 100% sensitive to cephalosporins but at least 83.3% showed resistance against chloramphenicol and tetracycline. At least 66.7% of isolates were multidrug resistance (MDR). Using well water for drinking (AOR = 6.22, CI 1.4-27.5) and previous EF history (AOR = 10.74, CI 2.01-55.9) were significantly associated with EF infection. Thus high bacterial prevalence and MDR isolates was observed. Therefore, health professionals should consider AST and use antibiotics with cautions for EF patient management.

A systematic review of antimicrobial resistance of typhoidal Salmonella in India

Background & objectives:

The temporal trends in the development of antimicrobial resistance (AMR) among Salmonella Typhi and Salmonella Paratyphi in India have not been systematically reported. We aimed to systematically review the temporal AMR trends (phenotypic and molecular mechanisms) in bacterial isolates from patients with enteric fever over two decades in India.

Methods:

To identify trends in AMR in India, resistance patterns among 4611 individual S. Typhi isolates and 800 S. Paratyphi A isolates, reported from 1992 to 2017 in 40 publications, were analysed. Molecular resistance determinants were extracted from 22 publications and also reviewed in accordance with the PRISMA guidelines. Articles were sourced using a predefined search strategy from different databases.

Results:

The analyses suggested that multidrug-resistant (MDR) enteric fever was declining in India and being replaced by fluoroquinolone (FQ) resistance. Mutations in gyrA and parC were key mechanisms responsible for FQ resistance, whereas MDR was largely driven by resistance determinants encoded on mobile genetic elements (plasmids, transposons).

Interpretation & conclusions:

The results reflect the effect of antimicrobial pressure which has been driving AMR in typhoidal Salmonella in India. Understanding these trends is important in planning future approaches to therapy, which serve as a baseline for assessment of the impact of new typhoid conjugate vaccines against these resistant organisms.

A Retrospective Review of Hospital-Based Data on Enteric Fever in India, 2014-2015

Background

Enteric fever remains a threat to many countries with minimal access to clean water and poor sanitation infrastructure. As part of a multisite surveillance study, we conducted a retrospective review of records in 5 hospitals across India to gather evidence on the burden of enteric fever.

Methods

We examined hospital records (laboratory and surgical registers) from 5 hospitals across India for laboratory-confirmed Salmonella Typhi or Salmonella Paratyphi cases and intestinal perforations from 2014–2015. Clinical data were obtained where available. For laboratory-confirmed infections, we compared differences in disease burden, age, sex, clinical presentation, and antimicrobial resistance.

Results

Of 267536 blood cultures, 1418 (0.53%) were positive for S. Typhi or S. Paratyphi. Clinical data were available for 429 cases (72%); a higher proportion of participants with S. Typhi infection were hospitalized, compared with those with S. Paratyphi infection (44% vs 35%). We observed resistance to quinolones among 82% of isolates, with cases of cephalosporin resistance (1%) and macrolide resistance (9%) detected. Of 94 participants with intestinal perforations, 16 (17%) had a provisional, final, or laboratory-confirmed diagnosis of enteric fever.

Discussion

Data show a moderate burden of enteric fever in India. Enteric fever data should be systematically collected to facilitate evidence-based decision-making by countries for typhoid conjugate vaccines.

Antimicrobial susceptibility to azithromycin among Salmonella enterica Typhi and Paratyphi A isolates from India

Decreased ciprofloxacin susceptibility (DCS) and multidrug resistance in typhoidal Salmonella isolates in areas of endemicity are significant therapeutic problems. Guidelines for azithromycin disc diffusion and MIC interpretive criteria for Salmonella enterica serovar Typhi were published recently by the Clinical and Laboratory Standards Institute in 2015. We investigated the antimicrobial susceptibility pattern of azithromycin in 100 isolates of Salmonella Typhi (n=80), Paratyphi A (n=18) and B (n=2) recovered from bloodstream infections from January 2013 to December 2015. Zone sizes were extrapolated against MIC values, and a scatter plot was constructed. The azithromycin MICs by Etest ranged from 2 to 16 µg ml-1, while the disc diffusion diameters were from 13 to 22 mm. We observed that the margin of the zone of inhibition around the azithromycin disc may not be very clear and therefore difficult to interpret and that there was wide variation in the zone sizes for the same MIC value in both serovars. DCS was observed in 85 % of Salmonella Typhi recovered (68/80) and in 15/18 (83.3 %) Paratyphi A isolates. Judicious use of azithromycin is advocated as an alternative oral agent in endemic areas where DCS is common.

Antimicrobial susceptibility pattern and sequence analysis of DNA gyrase and DNA topoisomerase IV in Salmonella enterica serovars Typhi and Paratyphi A isolates with decreased susceptibility to ciprofloxacin

BACKGROUND

We describe the antimicrobial susceptibility pattern of 100 typhoidal Salmonella isolates recovered from blood cultures and also investigate the association of decreased ciprofloxacin susceptibility with mutations in the genes coding for DNA gyrase and topoisomerase IV in 55 isolates.

METHODS

The study was conducted between January 2013 and December 2015 at a tertiary care centre in north India. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion and E-test. Genotypic characterization included the screening of mutations in the quinolone resistance-determining region of gyrA, gyrB, parC, and parE by PCR. DNA sequence analysis was done for 55 isolates.

RESULTS

Out of 100 isolates recovered 80 were S. Typhi, 18 were Paratyphi A and two were Paratyphi B. Eighty two percent (66/80) of S. Typhi and 15/18 S. Paratyphi A showed decreased ciprofloxacin susceptibility. The most common mutation in gyrA led to a change at codon 83 of serine to phenylalanine (n=37) or tyrosine (n=12). Five S. Typhi isolates that were resistant to ciprofloxacin (MICs of 12, 16, 24 and 32 μg/ml) had a second mutation at codon 87 in the gyrA gene changing aspartate to asparagine.

CONCLUSIONS

There is a need to urgently review the use of fluoroquinolones for the management of enteric fever in endemic areas.