Following a year of valganciclovir prophylaxis, a lung transplant recipient developed cytomegalovirus (CMV) infection that became resistant to ganciclovir, as confirmed by detection of UL97 kinase mutation M460V and a previously uncharacterized UL54 DNA polymerase mutation L516P. The latter mutation is now shown to confer ganciclovir and cidofovir resistance. As predicted from the viral genotype, foscarnet therapy was effective, but resumption of valganciclovir as secondary prophylaxis resulted in a plasma viral load rebound to 3.6 log10 copies/mL several weeks later. Valganciclovir was then replaced by letermovir, resulting in gradual viral load reduction in the first 5 weeks to below the quantitation limit (2.7 log10 copies/mL) for one week, followed by 10 weeks of rising viral loads reaching 4.3 log10 copies/mL while on letermovir. At this point, CMV genotypic testing revealed UL56 mutation C325Y, which confers absolute resistance to letermovir. Retreatment with foscarnet was successful. This case adds to the considerable list of proven ganciclovir resistance mutations, and provides an early experience with letermovir resistance after off-label therapeutic use. This experience is consistent with in vitro observations of rapid emergence of letermovir-resistant CMV after drug exposure.

Increasing bacterial resistance and poor patient adherence rates limit the effectiveness of conventional antibiotic therapies for urinary tract infection (UTI). The objective of this study was to investigate whether a single aminoglycoside dose adequately treated UTI. A systematic search of PubMed/MEDLINE and Google Scholar databases was performed through September 2018 for English language original research articles assessing the efficacy of one-time parenteral aminoglycoside as UTI monotherapy. Of 252 potentially relevant studies, 13 studies met the inclusion criteria, representing 13,804 patients. Patient ages ranged from 2 weeks to >70 years; both inpatient and outpatient settings were represented. Cystitis was more common than pyelonephritis, and more females were represented than males.Escherichia coliwas the most commonly isolated uropathogen. The pooled microbiologic cure rate with single-dose aminoglycoside therapy was 94.5% ± 4.3%. Cure was sustained (no recurrence) for 73.4% ± 9.6% of patients at day 30. Lower cure rates were observed among patients with radiographic urinary tract abnormality (chi-squareP < 0.01). Across all studies, 63/13,804 (0.5%) cases of nephrotoxicity, vestibular toxicity, or injection site reaction were reported; no hearing loss was observed. Single-dose aminoglycoside therapy appears to be an effective treatment option for lower UTI in nonseptic patients, with minimal toxicity. Additional studies would be beneficial to confirm efficacy for pyelonephritis. When resistance to first-line UTI agents is endemic, aminoglycosides may serve as β-lactam- and fluoroquinolone-sparing options.

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Complicated intra-abdominal infections (cIAI) represent a large proportion of all hospital admissions and are a major cause of morbidity and mortality in the intensive care unit. Rising rates of multidrug resistant organisms (MDRO), including extended-spectrum β-lactamase producing Enterobacteriaceae and carbapenem-nonsusceptible Pseudomonas spp., for which there are few remaining active antimicrobial agents, pose an increased challenge to clinicians. Patients with frequent exposures to the health care system or multiple recurrent IAIs are at increased risk for MDRO; however, treatment options have traditionally been limited, in some cases necessitating the utilization of last-line agents with unfavorable side-effect profiles. Ceftolozane/tazobactam and ceftazidime/avibactam are two new cephalosporin and β-lactamase inhibitor combinations with recent US Food and Drug Administration approvals for the treatment of cIAI in combination with metronidazole. Ceftolozane/tazobactam has demonstrated excellent in vitro activity against MDR and extensively drug-resistant Pseudomonas spp., including carbapenem-nonsusceptible strains, while ceftazidime/avibactam effectively inhibits a broad range of β-lactamases, making it an excellent option for the treatment of carbapenem-resistant Enterobacteriaceae. Both agents were shown to be noninferior to meropenem for treatment of cIAI in Phase III trials; however, reduced responses in patients with renal impairment at baseline highlight the importance of routine serum creatinine monitoring and ongoing dose adjustments. This review highlights in vitro and in vivo data of these two agents and suggests their proper place in cIAI treatment to ensure adequate therapy in our most at-risk patients while sparing unnecessary use in patients without MDRO risk factors.

Psychotropic medications are frequently co-prescribed with antiretroviral therapy (ART), owing to a high prevalence of psychiatric illness within the population living with HIV, as well as a 7-fold increased risk of HIV infection among patients with psychiatric illness. While ART has been notoriously associated with a multitude of pharmacokinetic drug interactions involving the cytochrome P450 enzyme system, the magnitude and clinical impact of these interactions with psychotropics may range from negligible effects on plasma concentrations to life-threatening torsades de pointes or respiratory depression. This comprehensive review summarizes the currently available information regarding drug–drug interactions between antiretrovirals and pharmacologic agents utilized in the treatment of psychiatric disorders—antidepressants, stimulants, antipsychotics, anxiolytics, mood stabilizers, and treatments for opioid use disorder and alcohol use disorder—and provides recommendations for their management. Additionally, overlapping toxicities between antiretrovirals and the psychotropic classes are highlighted. Knowledge of the interaction and adverse effect potential of specific antiretrovirals and psychotropics will allow clinicians to make informed prescribing decisions to better promote the health and wellness of this high-risk population.