Clinical outcomes of elderly patients with bloodstream infections due to extended-spectrum ß-lactamase-producing Enterobacteriaceae in an Italian Internal Medicine ward.

PURPOSE: Infections caused by ESBL-producing Enterobacteriaceae (ESBL-EB) are a major health problem, but data regarding elderly patients is lacking. METHODS: We performed a retrospective observational study quantifying the effects of antimicrobial treatment and primary infection site on clinical outcomes in an historical case series of 42 patients aged 80.7±10years admitted to an Internal Medicine ward in Italy for ESBL-EB bloodstream infections (BSI). RESULTS: At multivariate risk analysis, we found that urinary tract as primary infection site (RR=0.181 [0.037-0.886], p=0.035) and definitive antibiotic therapy (RR=0.517 [0.147-0.799], p=0.038) decreased the relative risk of a negative clinical response, while the respiratory tract origin increased the relative risk (RR=2.788 [1.407-9.228], p=0.025). Also regarding 30days mortality, multivariate risk analysis identified that urinary tract as primary infection site (RR=0.098 [0.011-0.743], p=0.025) and definitive antibiotic therapy (RR=0.236 [0.058-0.961], p=0.044) decreased the relative risk, while the respiratory origin increased the relative risk (RR=4.241 [1.040-17.295], p=0.014). We observed similar outcomes in patients definitively treated with carbapenems or with carbapenem-free treatments. Additionally, an initially inappropriate therapy did not correlate with worse outcomes if a switch to an effective definitive treatment was performed promptly. CONCLUSIONS: Carbapenem-sparing regimens (e.g. piperacillin-tazobactam alone or with an aminoglycoside) could be empirically safely used in elderly patients at high risk of ESBL-EB BSI and for definitive treatment of ascertained cases if the primary site is the urinary tract, leaving early carbapenem use for cases at higher risk of death, such as those with pneumonia.

Usefulness of procalcitonin in differentiating Candida and bacterial blood stream infections in critically ill septic patients outside the intensive care unit.

We aimed to explore the role of procalcitonin (PCT) for the diagnosis of Candida spp. bloodstream infections in a population of critically ill septic patients admitted to internal medicine units. This is a retrospective case-control study considering all cases of candidemia identified in three internal medicine units, from January 1st 2012 to May 31st 2016. For each case of candidemia, two patients with bacteremic sepsis were included in the study as control cases. The end point of the study was to evaluate the diagnostic performance of PCT for the diagnosis of Candida spp. blood stream infections in patients with objectively documented sepsis. Sixty-four patients with candidemia and 128 controls with bacteremia were enrolled. Median and interquartile range (IQR) PCT values are significantly lower in patients with candidemia (0.73; IQR 0.26-1.85 ng/mL) than in those with bacteremia (4.48; IQR 1.10-18.26 ng/mL). At ROC curve analysis, values of PCT greater than 2.5 ng/mL had a negative predictive value (NPV) of 98.3% with an AUC of 0.76 (0.68-0.84 95% CI) for the identification of Candida spp. from blood cultures. At multivariate analysis, a PCT value <2.5 ng/mL showed an odds ratio of 8.57 (95% CI 3.09-23.70; p < 0.0001) for candidemia. In septic patients at risk of Candida infection, a PCT value lower than 2.5 ng/mL should raise the suspicion of candidemia, adding value for considering prompt initiation of antifungal therapy.

Low prevalence of methicillin-resistant Staphylococcus aureus nasal carriage in urban and rural community settings in Bolivia and Peru.

OBJECTIVE: To investigate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in rural and urban community settings of Bolivia and Peru. METHODS: MRSA nasal carriage was investigated in 585 individuals living in rural and urban areas of Bolivia and Peru (one urban area, one small rural village, and two native communities, one of which was highly isolated). MRSA isolates were subjected to molecular analysis for the detection of virulence genes, characterization of the staphylococcal cassette chromosome mec (SCCmec), and genotyping (multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE)). RESULTS: An overall very low prevalence of MRSA nasal carriage was observed (0.5%), with MRSA carriers being detected only in a small rural village of the Bolivian Chaco. The three MRSA isolates showed the characteristics of community-associated MRSA (being susceptible to all non-beta-lactam antibiotics and harboring the SCCmec type IV), were clonally related, and belonged to ST1649. CONCLUSIONS: This study provides an insight into the epidemiology of MRSA in community settings of Bolivia and Peru. Reliable, time-saving, and low-cost methods should be implemented to encourage continued surveillance of MRSA dissemination in resource-limited countries.

Quinolone resistance in absence of selective pressure: the experience of a very remote community in the Amazon forest.

BACKGROUND: Quinolones are potent broad-spectrum bactericidal agents increasingly employed also in resource-limited countries. Resistance to quinolones is an increasing problem, known to be strongly associated with quinolone exposure. We report on the emergence of quinolone resistance in a very remote community in the Amazon forest, where quinolones have never been used and quinolone resistance was absent in 2002. METHODS: The community exhibited a considerable level of geographical isolation, limited contact with the exterior and minimal antibiotic use (not including quinolones). In December 2009, fecal carriage of antibiotic resistant Escherichia coli was investigated in 120 of the 140 inhabitants, and in 48 animals reared in the community. All fluoroquinolone-resistant isolates were genotyped and characterized for the mechanisms of plasmid- and chromosomal-mediated quinolone resistance. PRINCIPAL FINDINGS: Despite the characteristics of the community remained substantially unchanged during the period 2002-2009, carriage of quinolone-resistant E. coli was found to be common in 2009 both in humans (45% nalidixic acid, 14% ciprofloxacin) and animals (54% nalidixic acid, 23% ciprofloxacin). Ciprofloxacin-resistant isolates of human and animal origin showed multidrug resistance phenotypes, a high level of genetic heterogeneity, and a combination of GyrA (Ser83Leu and Asp87Asn) and ParC (Ser80Ile) substitutions commonly observed in fluoroquinolone-resistant clinical isolates of E. coli. CONCLUSIONS: Remoteness and absence of antibiotic selective pressure did not protect the community from the remarkable emergence of quinolone resistance in E. coli. Introduction of the resistant strains from antibiotic-exposed settings is the most likely source, while persistence and dissemination in the absence of quinolone exposure is likely mostly related with poor sanitation. Interventions aimed at reducing the spreading of resistant isolates (by improving sanitation and water/food safety) are urgently needed to preserve the efficacy of quinolones in resource-limited countries, as control strategies based only on antibiotic restriction policies are unlikely to succeed in those settings.