Treatment outcomes of patients with non-bacteremic pneumonia caused by extensively drug-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex isolates

Abstract

Few therapeutic options exist for various infections caused by extensively drug-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii (XDR-Acb) complex isolates, including pneumonia. This study investigated the clinical efficacy between aerosolized colistimethate sodium (AS-CMS, 2 million units thrice a day) treatment alone or in combination with standard-dose tigecycline (TGC) in patients with non-bacteremic pneumonia due to XDR-Acb, and explored the factors influencing patients’ 30-day mortality.A 1:1 case (n = 106; receiving TGC plus AS-CMS) control (receiving AS-CMS alone with matching scores) observational study was conducted among adult patients with non-bacteremic XDR-Acb complex pneumonia in a Taiwanese medical center from January 2014 through December 2016. The clinically relevant data were retrospectively recorded. The primary endpoint was 30-day case fatality. Secondary endpoints investigated that if the co-morbidities, XDR-A. baumannii as a pneumonic pathogen, therapy-related factors, or airway colonization with colistin-resistant Acb negatively influenced the 14-day clinical condition of enrolled patients.A higher 30-day mortality rate was noted among the group receiving combination therapy (34.0% vs 22.6%; P = .17). The ≥7-day AS-CMS therapy successfully eradicated > 90% of airway XDR-Acb isolates. Nevertheless, follow-up sputum specimens from 10 (6.4% [10/156]) patients were colonized with colistin-resistant Acb isolates. After the conditional factors were adjusted by multivariate logistic analysis, the only factor independently predicting the 30-day case-fatality was the failure of treating XDR-Acb pneumonia at 14 days (adjusted odds ratio [aOR] = 38.2; 95% confidence interval [CI] = 9.96–142.29; P < .001). Cox proportional regression analysis found that chronic obstructive pulmonary disease (COPD) (adjusted hazard ratio [aHR] = 2.08; 95% CI = 1.05–4.10; P = .035), chronic renal failure (aHR = 3.00; 95% CI = 1.52–5.90; P = .002), non-invasive ventilation use (aHR = 2.68; 95% CI = 1.37–5.25; P = .004), and lack of TGC therapy (aHR = 0.52; 95% CI = 0.27–1.00; P = .049) adversely influenced the 14-day clinical outcomes. Conversely, the emergence of colistin-resistant Acb isolates in the follow-up sputum samples was not statistically significantly associated with curing or improving XDR-Acb pneumonia.In conclusion, aggressive pulmonary hygiene care, the addition of TGC, and corticosteroid dose tapering were beneficial in improving the 14-day patients’ outcomes.

Epidemiology, Treatment, and Prevention of Nosocomial Bacterial Pneumonia

“…A Spanish study investigating the outcomes of ICU patients with VAP caused by P. aeruginosa observed that initial use of antibiotic combination therapy (mainly anti-pseudomonal β-lactam plus an aminoglycoside or an anti-pseudomonal fluoroquinolone agent) indeed significantly reduced the likelihood of inappropriate therapy, which was strongly associated with higher case-fatality risk [97]. Nevertheless, in distinction from two guidelines [11,14], there were many diversified regimens of antibiotic combinations proposed against clinical infections due to isolates of CR-Acinetobacter baumannii complex species [59,75,80,[98][99][100], as well as CRE [34,69,94,101]. Despite no reduction of mortality rates [11], a useful de-escalation of an antibiotic has the benefit of decreasing resistance burden.…”

Epidemiology and clinical outcomes associated with extensively drug-resistant (XDR) Acinetobacter in US Veterans’ Affairs (VA) medical centers

“…Isolation of XDRAB has been associated with high in-hospital and 30-day mortality in prior studies. [8][9][10] Although some of this association is explained by the propensity of Acinetobacter to infect hospitalized, medically complex patients with high baseline risk for mortality, prior studies have shown substantial attributable mortality from MDRAB infections specifically. 4,12 Our study had several important limitations.…”

“…Existing data on XDRAB come largely from smaller, single-center studies conducted outside the United States. [8][9][10] In this national cohort study, we used data from US Department of Veterans' Affairs (VA) hospitals to describe the epidemiology, clinical characteristics, and outcomes for patients with XDRAB in the VA.…”

Re: ‘Efficacy and safety of tocilizumab in COVID-19 patients: a living systematic review and meta-analysis’ by Tleyjeh et al.

“…As a result of the impact of assessment criteria and administration route on observed nephrotoxicity rates, subsequent subgroup analyses of the nephrotoxicity rate were performed in a secondary analysis population that included only studies using internationally recognized assessment criteria (RIFLE, AKIN or KDIGO) and excluded ten studies in which less than 50% patients received systemic polymyxins [19,26,53,66,71,119,143,147,155,243]. The results of these subanalyses are presented here, whereas metaanalyses of the nephrotoxicity rate including all 237 studies regardless of AKI criteria and administration route are presented in Supplementary Figs S1 to S17.…”