Lower respiratory tract infections are important causes of morbidity and mortality. The global increase in antimicrobial resistance necessitates rapid diagnostic assays. The BioFire FilmArray Pneumonia plus (FAPP) panel is an FDA approved multiplex polymerase chain reaction assay that detects the most important etiological agents of pneumonia, and associated antibiotic resistance genes, in approximately one hour. This study assessed the diagnostic performance of this assay by comparing it to conventional culture methods in the analysis of 59 lower respiratory tract specimens. The sensitivity and specificity of the FAPP panel for bacterial detection were 92.0% (95% CI, 80.8% - 97.8%) and 93.8% (95% CI, 91.1% - 95.3%) respectively. For detecting antibiotic resistance, the positive- and negative percent agreement were 100% (95% CI, 81.5% - 100.0%) and 98.5% (95% CI, 216 96.7% - 99.4%) respectively. The FAPP panel was found to be highly accurate in evaluating tracheal aspirate specimens from hospitalised patients.

Sepsis and septic shock are key contributors to mortality in critically ill patients and thus prompt recognition and management thereof is central to achieving improved patient outcomes. Early initiation of appropriate antimicrobial therapy constitutes a crucial component of the management strategy and thus early identification of the causative pathogen is essential in informing antimicrobial therapeutic choices. The BioFire FilmArray blood culture identification (BCID) panel is a US Food and Drug Administration (FDA) approved rapid, multiplex polymerase chain reaction assay for use on positive blood cultures. This study evaluated its clinical utility in the intensive care unit (ICU) setting, in terms of amendment of empiric antimicrobial therapy in critically ill patients with sepsis. The assay proved useful in this setting as final results were made available to clinicians significantly earlier than with conventional culture methods. This, in turn, allowed for modification of empirical antimicrobial therapy to more appropriate agents in 32% of patients. Additionally, the use of the BioFire FilmArray BCID panel permitted the prompt implementation of additional infection prevention and control practices in a sizeable proportion (14%) of patients in the study who were harbouring multidrug resistant pathogens. These findings support the use of the BioFire FilmArray BCID panel as a valuable adjunct to conventional culture methods for the diagnosis and subsequent management of critically ill patients with sepsis.

Background Non-typhoidal salmonellae (NTS) have been associated with invasive disease, notably meningitis, in immunocompromised individuals. Infections of this nature carry high rates of morbidity and mortality. Colistin resistance in salmonellae is a rare finding, more so in an invasive isolate such as cerebrospinal fluid (CSF). Colistin resistance has important infection control implications and failure to manage this phenomenon may lead to the loss of our last line of defence against multi-drug resistant Gram-negative organisms. To our knowledge, this is the first reported clinical case of colistin-resistant Salmonella Enteritidis meningitis in South Africa. Case presentation We report a case of a young male patient with advanced human immunodeficiency virus (HIV) infection who presented to hospital with symptoms of meningitis. Cerebrospinal fluid (CSF) cultured a Salmonella Enteritidis strain. Antimicrobial susceptibility testing (AST) of the isolate, revealed the strain to be colistin resistant. Despite early and aggressive antimicrobial therapy, the patient succumbed to the illness after a short stay in hospital. Subsequent genomic analysis of the isolate showed no presence of the mcr genes or resistance-conferring mutations in phoPQ, pmrAB, pmrHFIJKLME/arnBCADTEF, mgrB, and acrAB genes, suggesting the presence of a novel colistin resistance mechanism. Conclusion Invasive non-typhoidal salmonellae infection should be suspected in patients with advanced immunosuppression who present with clinical features of meningitis. Despite early and appropriate empiric therapy, these infections are commonly associated with adverse outcomes to the patient. Combination therapy with two active anti-Salmonella agents may be a consideration in the future to overcome the high mortality associated with NTS meningitis. Colistin resistance in clinical Salmonella isolates, although a rare finding at present, has significant public health and infection control implications. The causative mechanism of resistance should be sought in all cases.