Enhancement of Conventional Phenotypic Methods with Molecular-Based Methods for the More Definitive Identification of Nontuberculous Mycobacteria

Microbiologic Outcome of Interventions Against Mycobacterium avium Complex Pulmonary Disease: A Systematic Review

OBJECTIVE

Pulmonary disease (PD) caused by Mycobacterium avium complex (MAC) is increasing worldwide. We conducted a systematic review of studies that include microbiologic outcomes to evaluate current macrolide-based treatment regimens.

METHODS

We searched literature published before April 2017 by using the MEDLINE, Cochrane, and Embase databases. Risk of bias in randomized trials was assessed using the Cochrane tool.

RESULTS

We retrieved 333 citations and evaluated 42 studies including 2,748 patients: 18 studies were retrospective chart reviews, 18 were prospective, and six were randomized. The weighted average proportion of sputum culture conversions in macrolide-containing regimens after subtracting posttreatment microbiologic recurrences was 52.3% (95% CI, 44.7%-59.9%). Using the triple-drug regimens recommended by the American Thoracic Society (ATS) achieved treatment success in 61.4% (95% CI, 49.7%-72.5%), which further increased to 65.7% (95% CI, 53.3%-77.4%) when drugs were taken for at least 1 year by patients who were macrolide susceptible and had previously untreated MAC. The overall risk of bias was low in five of the six randomized trials. However, selective outcome reporting because of a posteriori exclusion of initially included patients (14.0%), uncompleted treatment (17.6%), and inconsistent use of outcome parameters (17 definitions of treatment success) hampered the comparison of nonrandomized trials.

CONCLUSIONS

To date, randomized studies on treatment outcome in patients with MAC PD are scarce. Long-term treatments with ATS-recommended regimens for patients who are macrolide susceptible are superior to other macrolide-based therapies. A standardized definition of treatment success and genotypic distinction between reinfection and relapse by means of pretreatment and posttreatment identification of MAC species in cases of microbiologic recurrences may help to optimize evaluation of treatment regimens in the future.

Prevention and Control of Antimicrobial Resistant Healthcare-Associated Infections: The Microbiology Laboratory Rocks!

In Europe, each year, more than four milion patients acquire a healthcare-associated infection (HAI) and almost 40 thousand die as a direct consequence of it. Regardless of many stategies to prevent and control HAIs, they remain an important cause of morbidity and mortality worldwide with a significant economic impact: a recent estimate places it at the ten billion dollars/year. The control of HAIs requires a prompt and efficient identification of the etiological agent and a rapid communication with the clinician. The Microbiology Laboratory has a significant role in the prevention and control of these infections and is a key element of any Infection Control Program. The work of the Microbiology Laboratory covers microbial isolation and identification, determination of antimicrobial susceptibility patterns, epidemiological surveillance and outbreak detection, education, and report of quality assured results. In this paper we address the role and importance of the Microbiology Laboratory in the prevention and control of HAI and in Antibiotic Stewardship Programs and how it can be leveraged when combined with the use of information systems. Additionally, we critically review some challenges that the Microbiology Laboratory has to deal with, including the selection of analytic methods and the proper use of communication channels with other healthcare services.

Skin and soft tissue infections caused by nontuberculous mycobacteria

PURPOSE OF REVIEW

Skin and soft tissues infections (SSTIs) caused by nontuberculous mycobacteria (NTM) are underrecognized and difficult to treat. Controversies exist for optimal medical management and the role of surgery. Defining the epidemiology in the environment, in animals and in healthcare aids disease prevention. This review focuses on recent advances in epidemiology, risk factors, diagnostics and therapy.

RECENT FINDINGS

The increasing consumer appetite for cosmetic and body-modifying procedures (e.g. tattooing, mesotherapy, liposuction) has been associated with rises in sporadic cases and outbreaks of NTM SSTIs. In mainstream healthcare, recent epidemiological studies have helped to quantify the increased risk of NTM infection related to anti-tumour necrosis factor-α monoclonal antibody therapy. Cervicofacial lymphadenitis in children poses management dilemmas, but recent studies and resultant algorithms have simplified decision-making. Molecular studies have led to a better understanding of the epidemiology, therapy and course of Mycobacterium ulcerans infection (Buruli ulcer) that remains prevalent in many areas including sub-Saharan Africa and southeastern Australia. Apart from molecular methods, the widespread adoption of matrix-assisted laser desorption ionization-time of flight mass spectrometry by routine laboratories has potential to simplify and expedite the laboratory identification of NTMs.

SUMMARY

An improved understanding of the epidemiology of NTM SSTIs indicates a need to apply effective infection control and ensure regulation of cosmetic and related procedures associated with nonsterile fluids. Broader access to newer diagnostic methods will continue to improve recognition of NTM disease. Along with a paucity of therapeutic agents, there is need for more reliable methods to assess susceptibility and selection of effective combination therapy.