Nontyphoidal Salmonella enterica Nonsusceptible to Both Levofloxacin and Ceftriaxone in Nebraska, United States 2014–2015

Rise of the (possible) resistance: a review of susceptibility patterns for nontyphoidal Salmonella enterica in Nebraska

Our institution sought to evaluate our antimicrobial stewardship empiric treatment recommendations for Salmonella. Results from 36 isolates demonstrated reduced susceptibilities to fluoroquinolones with 1 isolate susceptible only to ceftriaxone. Analysis supports the current recommendation of empiric ceftriaxone therapy for severe infection and updated recommendation for sulfamethoxazole-trimethoprim in non-severe infections.

Antimicrobial Resistance and Whole-Genome Characterisation of High-Level Ciprofloxacin-Resistant Salmonella Enterica Serovar Kentucky ST 198 Strains Isolated from Human in Poland

BACKGROUND

Salmonella Kentucky belongs to zoonotic serotypes that demonstrate that the high antimicrobial resistance and multidrug resistance (including fluoroquinolones) is an emerging problem. To the best of our knowledge, clinical S. Kentucky strains isolated in Poland remain undescribed.

METHODS

Eighteen clinical S. Kentucky strains collected in the years 2018-2019 in Poland were investigated. All the strains were tested for susceptibility to 11 antimicrobials using the disc diffusion and E-test methods. Whole genome sequences were analysed for antimicrobial resistance genes, mutations, the presence and structure of SGI1-K (Salmonella Genomic Island and the genetic relationship of the isolates.

RESULTS

Sixteen of 18 isolates (88.9%) were assigned as ST198 and were found to be high-level resistant to ampicillin (>256 mg/L) and quinolones (nalidixic acid MIC ≥ 1024 mg/L, ciprofloxacin MIC range 6-16 mg/L). All the 16 strains revealed three mutations in QRDR of GyrA and ParC. The substitutions of Ser83 → Phe and Asp87 → Tyr of the GyrA subunit and Ser80→Ile of the ParC subunit were the most common. One S. Kentucky isolate had qnrS1 in addition to the QRDR mutations. Five of the ST198 strains, grouped in cluster A, had multiple resistant determinants like blaTEM1-B, aac(6')-Iaa, sul1 or tetA, mostly in SGI1 K. Seven strains, grouped in cluster B, had shorter SGI1-K with deletions of many regions and with few resistance genes detected.

CONCLUSION

The results of this study demonstrated that a significant part of S. Kentucky isolates from humans in Poland belonged to ST198 and were high-level resistant to ampicillin and quinolones.

Associations of Salmonella hospitalizations with ambient temperature, humidity and rainfall in Hong Kong

BACKGROUND

Little is known about the relationship between Salmonella infection and meteorological parameters other than air temperature. This study aimed to explore associations of Salmonella hospitalizations with temperature, relative humidity (RH) and rainfall.

METHODS

With negative binomial distribution assumed, time-series regression model adjusting for season and time trend were constructed employing distributed lag non-linear models and generalized additive models. Meteorological variables including mean temperature, RH, and daily total rainfall as well as indicator variables including day of the week and public holiday were incorporated in the models.

RESULTS

Higher temperature was strongly associated with more hospitalizations over the entire range of temperatures observed. There was a net 6.13 (95%Confidence Interval (CI) 3.52-10.67) relative risk of hospitalization at a temperature of 30.5 °C, relative to 13 °C, lag 0-16 days. Positive associations were found for RH above 60% and rainfall between 0 and 0.14 mm. Extreme high humidity (96%) and trace rainfall (0.02 mm) were associated with 2.06 (95%CI 1.35-3.14), lag 0-17 day, and 1.30 (95%CI 1.01-1.67), lag 0-26 days, relative risks of hospitalizations, relative to 60% and no rain, respectively.

CONCLUSIONS

High temperatures, high RH and light rainfall are positively associated with Salmonella hospitalizations. The very strong association with temperatures implies that hotter days will lead to increases in Salmonella morbidity in the absence of other changes, and the public health implications of this could be exacerbated by global climate change.