Typhoid and paratyphoid fevers

Typhoid and paratyphoid fever (the enteric fevers) are caused by specific serovars of the Gram-negative bacillus, Salmonella enterica. Sources of typhoid transmission are excreting chronic or convalescent carriers and the acutely infected, with transmission occurring through contamination by carriers of food or water by effluents containing infected faeces or urine. Global estimates have varied between 12 and 27 million cases of enteric fever in the world each year, almost all in low- and middle-income countries, with about 200,000 deaths. Aside from supportive care, antibiotic therapy reduces mortality and complications and shortens the illness. Antibiotic resistance is a common and increasing problem, hence the choice of antibiotic should be informed by knowledge of likely local susceptibility.

Antimicrobial Susceptibility Trends Observed in Urinary Pathogens Obtained From New York State

International guidelines recommend using local susceptibility data to direct empiric therapy for acute uncomplicated cystitis. We evaluated outpatient urinary isolate susceptibility trends in New York State. Nitrofurantoin had the lowest resistance prevalence whereas trimethoprim-sulfamethoxazole and fluoroquinolones had higher prevalences. This study highlights the need for local outpatient antimicrobial stewardship programs.

Feasibility and Value of Developing a Regional Antibiogram for Community Hospitals

OBJECTIVETo determine the feasibility and value of developing a regional antibiogram for community hospitals.DESIGNMulticenter retrospective analysis of antibiograms.SETTING AND PARTICIPANTSA total of 20 community hospitals in central and eastern North Carolina and south central Virginia participated in this study.METHODSWe combined antibiogram data from participating hospitals for 13 clinically relevant gram-negative pathogen–antibiotic combinations. From this combined antibiogram, we developed a regional antibiogram based on the mean susceptibilities of the combined data.RESULTSWe combined a total of 69,778 bacterial isolates across 13 clinically relevant gram-negative pathogen–antibiotic combinations (median for each combination, 1100; range, 174–27,428). Across all pathogen–antibiotic combinations, 69% of local susceptibility rates fell within 1 SD of the regional mean susceptibility rate, and 97% of local susceptibilities fell within 2 SD of the regional mean susceptibility rate. No individual hospital had >1 pathogen–antibiotic combination with a local susceptibility rate >2 SD of the regional mean susceptibility rate. All hospitals’ local susceptibility rates were within 2 SD of the regional mean susceptibility rate for low-prevalence pathogens (<500 isolates cumulative for the region).CONCLUSIONSSmall community hospitals frequently cannot develop an accurate antibiogram due to a paucity of local data. A regional antibiogram is likely to provide clinically useful information to community hospitals for low-prevalence pathogens.Infect Control Hosp Epidemiol 2018;39:718–722

Results of a local combination therapy antibiogram for Pseudomonas aeruginosa isolates: is double worth the trouble?

Purpose: To determine the frequency at which fluoroquinolones and aminoglycosides demonstrate in vitro activity against non-urinary, non-skin/skin structure Pseudomonas aeruginosa isolates exhibiting decreased susceptibilities to one or more β-lactam agents. Methods: β-lactam-non-susceptible P. aeruginosa isolates recovered from blood, bone, lower respiratory tract, pleural fluid, cerebrospinal fluid, or peritoneal fluid cultures between October 2010 and October 2014 were reviewed from four community hospitals within a single health-system. Only the first isolate per patient was included for analysis. The likelihood that each isolate was susceptible to a non-β-lactam antimicrobial was then determined and summarized within a combination antibiogram. Results: In total, 179 P. aeruginosa isolates with decreased susceptibilities to one or more β-lactam agents were assessed. Because no appreciable differences in antimicrobial susceptibility profile were observed between hospitals, the isolates were evaluated in aggregate. Susceptibility rates for β-lactam monotherapy ranged from 34% to 75%. Aminoglycosides possessed increased antibacterial activity compared to fluoroquinolones. Tobramycin was the non-β-lactam most likely to expand antimicrobial coverage against β-lactam-non-susceptible P. aeruginosa with activity against 64%, 66%, and 65% of cefepime-, piperacillin-tazobactam-, and meropenem-non-susceptible isolates, respectively ( p < 0.001 for all). Conclusions: The results of this study support the use of aminoglycosides over fluoroquinolones for achieving optimal, empiric antimicrobial combination therapy for P. aeruginosa when dual antimicrobial therapy is clinically necessary. Future efforts aimed at optimizing combination therapy for P. aeruginosa should focus on systemic interventions that limit the selection of fluoroquinolones in combination with β-lactams to expand coverage based on local susceptibility rates.