Bacteremic nosocomial pneumonia caused by Acinetobacter baumannii and Acinetobacter nosocomialis: a single or two distinct clinical entities?

Lee, Y.-T.; Kuo, Shu‐Chen; Yang, Shi‐Ping; Lin, Yi Tsung; Chiang, Dung-Hung; Tseng, Fan-Chen; Chen, T.-L.; Fung, Chang Phone

doi:10.1111/j.1469-0691.2012.03988.x

Cited by 37 publications

(34 citation statements)

References 29 publications

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“…Several studies have shown that these different species within the ACB complex exhibit unique epidemiologic niches, drug resistance patterns, and virulence characteristics within the nosocomial environment (9, 10). In addition, recent studies have demonstrated that patients infected with non-baumannii ACB complex bacteria have fewer comorbidities and improved clinical outcomes than patients with A. baumannii infections (7,(11)(12)(13). Thus, determining the species within the ACB complex that is responsible for an infection has important medical implications.…”

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confidence: 99%

Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

2016

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bAcinetobacter baumannii frequently causes nosocomial infections and outbreaks. Whole-genome sequencing (WGS) is a promising technique for strain typing and outbreak investigations. We compared the performance of conventional methods with WGS for strain typing clinical Acinetobacter isolates and analyzing a carbapenem-resistant A. baumannii (CRAB) outbreak. We performed two band-based typing techniques (pulsed-field gel electrophoresis and repetitive extragenic palindromic-PCR), multilocus sequence type (MLST) analysis, and WGS on 148 Acinetobacter calcoaceticus-A. baumannii complex bloodstream isolates collected from a single hospital from 2005 to 2012. Phylogenetic trees inferred from core-genome single nucleotide polymorphisms (SNPs) confirmed three Acinetobacter species within this collection. Four major A. baumannii clonal lineages (as defined by MLST) circulated during the study, three of which are globally distributed and one of which is novel. WGS indicated that a threshold of 2,500 core SNPs accurately distinguished A. baumannii isolates from different clonal lineages. The bandbased techniques performed poorly in assigning isolates to clonal lineages and exhibited little agreement with sequence-based techniques. After applying WGS to a CRAB outbreak that occurred during the study, we identified a threshold of 2.5 core SNPs that distinguished nonoutbreak from outbreak strains. WGS was more discriminatory than the band-based techniques and was used to construct a more accurate transmission map that resolved many of the plausible transmission routes suggested by epidemiologic links. Our study demonstrates that WGS is superior to conventional techniques for A. baumannii strain typing and outbreak analysis. These findings support the incorporation of WGS into health care infection prevention efforts.A n important role of clinical microbiology is to identify relationships between bacterial isolates. At a broad level, phenotypic and genotypic tests are used to categorize bacterial isolates into the same or different species. Within a bacterial species, techniques are used to group isolates into clonal lineages, which are groups of closely related bacteria that share a recent common ancestor but have spread regionally or globally. At a more local level, infection control practitioners must determine whether a group of isolates constitutes a hospital outbreak by ascertaining whether the isolates have a degree of similarity consistent with a common source within the hospital. Once isolates belonging to a hospital outbreak have been identified, similarities and differences between these isolates can be exploited to generate a transmission map to aid in finding the source of the outbreak and in disrupting ongoing pathways of transmission. For some groups of bacteria, such as Acinetobacter, discernment at each level has medically important consequences and therefore must be accomplished by hospital-associated clinical microbiology laboratories.Within the Acinetobacter genus, the Acinetobacter calcoaceticusAcinetobac...

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Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

2016

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“…2 Species identification with commercial identification systems that are currently used in clinical microbiology laboratories remains problematic, and molecular methods have been developed and validated for identification of Acinetobacter species. 3 Given that A. baumannii, Acinetobacter genomic species 3, and Acinetobacter genomic species 13TU share important clinical and epidemiological characteristics, the need for species identification of the ACB complex in clinical microbiology laboratories is questionable. 3,4 Moreover, A. calcoaceticus is the environmental species that has frequently been recovered from soil and water, and the designation "ACB complex" may be misleading and not appropriate if used in a clinical context.…”

Section: Reply To Su and Chaomentioning

confidence: 99%

“…3 Given that A. baumannii, Acinetobacter genomic species 3, and Acinetobacter genomic species 13TU share important clinical and epidemiological characteristics, the need for species identification of the ACB complex in clinical microbiology laboratories is questionable. 3,4 Moreover, A. calcoaceticus is the environmental species that has frequently been recovered from soil and water, and the designation "ACB complex" may be misleading and not appropriate if used in a clinical context. 3 The majority of studies that have addressed epidemiological and clinical issues related to Acinetobacter, including ours, have not employed identification methods for the ACB complex.…”

Section: Reply To Su and Chaomentioning

confidence: 99%

“…3,4 Moreover, A. calcoaceticus is the environmental species that has frequently been recovered from soil and water, and the designation "ACB complex" may be misleading and not appropriate if used in a clinical context. 3 The majority of studies that have addressed epidemiological and clinical issues related to Acinetobacter, including ours, have not employed identification methods for the ACB complex. 2 ' 3 However, further clinical studies using proper methods for species identification of Acinetobacter are warranted to increase our knowledge of the epidemiology, pathogenicity, and clinical implications of the various species of this diverse genus.…”

Section: Reply To Su and Chaomentioning

confidence: 99%

“…After the introduction of molecular methods to accurately identify each genospecies, the clinical characteristics of each have been clarified, and it has been better realized that every genospecies has its own distinct features. For example, in the latest study by Lee et al, 3 patients with A. baumannii pneumonia were more likely to have abnormal hematological findings, lobar pneumonia, significantly higher Acute Physiology and Chronic Health Evaluation II scores, and higher mortality than those with A. nosocomialis pneumonia. Thus, they concluded that A. baumannii and A. nosocomialis nosocomial pneumonia are 2 distinct clinical entities.…”

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Acinetobacter calcoaceticus–Acinetobacter baumannii Complex Is Not Equal to A. baumannii

Chao

2013

Infect. Control Hosp. Epidemiol.

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many important nonstandard indicators of patient care-can easily be extended to hand hygiene surveillance. Because logins linked to computers in patient rooms correlate with actual visits by HCWs vis-a-vis hand hygiene opportunities arising from HCW/patient contact, they can also be used to estimate temporal patterns appropriate for effectively monitoring hand hygiene activity levels.To validate our new method, we used 660 days of UIHC MICU log-in data (September 1, 2006, through June 21, 2008, restricted to those log-ins linked to patient rooms (a total of 1,757 unique users). We then counted the number of unique users who log in for every hour for each day in our data set. For each day and night shift, we then rank ordered each hour on the basis of the number of unique individual log-ins observed (the choice of this metric was motivated by our simulations of hand hygiene compliance, which show that methodologies that favor observing more unique individuals rather than more events results in a better overall estimate of unit compliance, in essence by reducing sample bias in population selection). The resulting distribution of each hour's respective rank is then calculated across the entire data set and validated against a similar rank-order statistic derived from the sensor-mote data, where each hour in the shift is ranked by median number of captured hand hygiene events.Overall, we found that the observed hourly, unique HCW log-ins in our sensor data set are highly correlated with the same measure in our log-in data, with a Spearman's p of 0.86 (P<.001).Choosing a single observation hour on the basis of log-in rank results in selecting the single best hour 22% and 29% of the time for the day and night shift, respectively, a 2.5-3-fold improvement over simply selecting an hour at random. If we instead select the top quartile of hours per shift, it will contain the best hour 47% and 60% of the time for the day and night shift, respectively, a 1.5-2.5-fold improvement over uniform random selection. More generally, because this approach calculates qualitative rankings for each hour, we can both identify alternate candidate hours for observation (eg, the second-best hour to observe) and identify candidates that are consistently the best hours for observation compared with other, more variable candidate hours. By examining the variability (ie, entropy) of a given hour's rankings, we find that the best hours for observation tend to be those with lower variability for a shift-that is, their rankings are more stable across any given day. As a last point, all these results assume a static choice of observation hour across the entire data set. An obvious improvement would be a dynamic schedule in which an algorithm uses a window of recent log-in data to propose different candidate hours, providing real-time guidance to observers on which hours to monitor. We leave this idea for exploration in future work.Data-driven approaches are being applied to problems in health care with increasing regularity. Improving hand hygien...

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Imaging mass spectrometry for assessing temporal proteomics: Analysis of calprotectin in Acinetobacter baumannii pulmonary infection

et al. 2013

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Imaging MS is routinely used to show spatial localization of proteins within a tissue sample and can also be employed to study temporal protein dynamics. The antimicrobial S100 protein calprotectin, a heterodimer of subunits S100A8 and S100A9, is an abundant cytosolic component of neutrophils. Using imaging MS, calprotectin can be detected as a marker of the inflammatory response to bacterial challenge. In a murine model of Acinetobacter baumannii pneumonia, protein images of S100A8 and S100A9 collected at different time points throughout infection aid in visualization of the innate immune response to this pathogen. Calprotectin is detectable within 6 h of infection as immune cells respond to the invading pathogen. As the bacterial burden decreases, signals from the inflammatory proteins decrease. Calprotectin is no longer detectable 96–144 h post infection, correlating to a lack of detectable bacterial burden in lungs. These experiments provide a label-free, multiplexed approach to study host response to a bacterial threat and eventual clearance of the pathogen over time.

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Bacteremic nosocomial pneumonia caused by Acinetobacter baumannii and Acinetobacter nosocomialis: a single or two distinct clinical entities?

Cited by 37 publications

References 29 publications

Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

Acinetobacter calcoaceticus–Acinetobacter baumannii Complex Is Not Equal to A. baumannii

Imaging mass spectrometry for assessing temporal proteomics: Analysis of calprotectin in Acinetobacter baumannii pulmonary infection

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