Aztreonam-Avibactam Susceptibility Testing Program for Metallo-Beta-Lactamase-Producing Enterobacterales in the Antibiotic Resistance Laboratory Network, March 2019 to December 2020.

Aztreonam-avibactam is a drug combination pending phase 3 clinical trials and is suggested for treatment of severe infections caused by metallo-beta-lactamase (MBL)-producing Enterobacterales by combining ceftazidime-avibactam and aztreonam. Beginning in 2019, four Antibiotic Resistance Laboratory Network regional laboratories offered aztreonam-avibactam susceptibility testing by broth microdilution. For 64 clinical isolates tested, the MIC50 and MIC90 values of aztreonam-avibactam were 0.5/4 µg/ml and 8/4 µg/ml, respectively. Aztreonam-avibactam displayed potent in vitro activity against the MBL-producing Enterobacterales tested.

Oral Prevalence of Akkermansia muciniphila Differs among Pediatric and Adult Orthodontic and Non-Orthodontic Patients.

Akkermansia muciniphila (AM) is one of many highly abundant intestinal microbes that influences homeostasis and metabolic disorders and may also play a role in oral disorders. However, there is little evidence regarding the oral prevalence of this organism. Based upon this lack of evidence, the primary goal of this project is to survey an existing saliva repository to determine the overall prevalence of this organism and any associations with demographic or patient characteristics (age, sex, body mass index, race/ethnicity, orthodontic therapy). Using an approved protocol,, a total n = 141 pediatric samples from an existing saliva repository were screened using qPCR revealing 29.8% harbored AM with nearly equal distribution among males and females, p = 0.8347. Significantly higher percentages of pediatric, non-orthodontic patients were positive for AM (42.3%) compared with age-matched orthodontic patients (14.3%)-which were equally distributed among non-orthodontic males (42.1%) and non-orthodontic females (42.5%). In addition, analysis of the adult samples revealed that nearly equal percentages of males (18.2%) and females (16.7%) harbored detectable levels of salivary AM, p = 0.2035. However, a higher proportion of non-orthodontic adult samples harbored AM (21.3%) compared to orthodontic samples (12.8%, p = 0.0001), which was equally distributed among males and females. These results suggest that both age and the presence of orthodontic brackets may influence microbial composition and, more specifically, are associated with reduction in AM among both pediatric and adult populations from their baseline levels.

Prevalence of Oral Pathogen Slackia exigua among Clinical Orthodontic and Non-Orthodontic Saliva Samples.

Slackia exigua (SE) is a recently identified intestinal microbe, which recent oral surveys suggest may be associated with oral diseases including caries and periodontal disease. Based upon the lack of information regarding this organism, the primary objective of this study was to determine the oral prevalence of this microbe and any potential associations with patient characteristics such as age, sex, or the presence of orthodontic appliances. This retrospective study involved the screening of an existing saliva repository composed of previously collected unstimulated clinical saliva samples. More specifically, N = 266 were identified and screened using a spectrophotometer at absorbances of A260 and A280 nm to determine their DNA purity and concentration. qPCR screening of these samples revealed a higher prevalence of Slackia exigua positive samples among pediatric patients (63.1%) compared with adults (36.9%) in this clinic population, p = 0.0007. In addition, higher percentages of Slackia exigua were observed among orthodontic patients (71.2%) compared with non-orthodontic patients (28.8%), p = 0.0001. These results did not vary by sex with nearly equal percentages of Slackia exigua positive males and females among adult and pediatric patients, as well as orthodontic and non-orthodontic samples. These results suggest a strong potential for association between the prevalence of this organism with age as well as orthodontic status, given that younger patients and those with orthodontic brackets (regardless of age) were most likely to harbor this pathogen in sufficient levels to be detected in saliva. More research will be needed to determine any associations with specific outcomes, such as caries or periodontal disease, among Slackia exigua positive patients within these specific populations.