Invasive Infection Group Research Articles

Distribution of virulence genes and antimicrobial resistance of Escherichia coli isolated from hospitalized neonates: A multi-center study across China

BackgroundEscherichia coli is the most common gram-negative pathogen to cause neonatal infections. Contemporary virulence characterization and antimicrobial resistance (AMR) data of neonatal E. coli isolates in China are limited. MethodsA total of 159 E. coli strains isolated from neonates were collected and classified into invasive and non-invasive infection groups, according to their site of origin. The presence of virulence genes was determined using polymerase chain reaction (PCR). All the strains were subjected to antimicrobial susceptibility testing using the broth dilution method. ResultsThe top three virulence genes with the highest detection rates were fimH (90.6 %), iutA (88.7 %), and kspMT II (88.1 %). The prevalences of fyuA (p = 0.023), kpsMT K1 (p = 0.019), ibeA (p < 0.001), and iroN (p = 0.027) were significantly higher in the invasive infection group than in the non-invasive infection group. Resistance to ceftazixime, sulfamethoxazole/trimethoprim, and ciprofloxacin was 75.5 %, 65.4 %, and 48.4 %, respectively. Lower rates of resistance to ceftazidime (p = 0.022), cefepime (p = 0.005), ticarcillin/clavulanic acid (p = 0.020) and aztreonam (p = 0.001) were observed in the invasive infection group compared to the non-invasive infection group. The number of virulence genes carried by E. coli was positively correlated with the number of antibiotics to which the isolates were resistant (r = 0.71, p = 0.016), and a specific virulence gene was associated with resistance to various species of antibiotics. ConclusionsNeonatal E. coli isolates carried multiple virulence genes and were highly resistant to antibiotics. Further studies are needed to understand the molecular mechanisms underlying the association between virulence and AMR.

Virulence Factors Found in Nasal Colonization and Infection of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates and Their Ability to Form a Biofilm

Hospitalizations related to Methicillin-resistant Staphylococcus aureus (MRSA) are frequent, increasing mortality and health costs. In this way, this study aimed to compare the genotypic and phenotypic characteristics of MRSA isolates that colonize and infect patients seen at two hospitals in the city of Niterói—Rio de Janeiro, Brazil. A total of 147 samples collected between March 2013 and December 2015 were phenotyped and genotyped to identify the protein A (SPA) gene, the mec staphylococcal chromosomal cassette (SCCmec), mecA, Panton-Valentine Leucocidin (PVL), icaC, icaR, ACME, and hla virulence genes. The strength of biofilm formation has also been exploited. The prevalence of SCCmec type IV (77.1%) was observed in the colonization group; however, in the invasive infection group, SCCmec type II was prevalent (62.9%). The Multilocus Sequence Typing (MLST), ST5/ST30, and ST5/ST239 analyses were the most frequent clones in colonization, and invasive infection isolates, respectively. Among the isolates selected to assess the ability to form a biofilm, 51.06% were classified as strong biofilm builders. Surprisingly, we observed that isolates other than the Brazilian Epidemic Clone (BEC) have appeared in Brazilian hospitals. The virulence profile has changed among these isolates since the ACME type I and II genes were also identified in this collection.

Rhino-oculocerebral Mucormycosis

Mucormycoses are a group of invasive infections caused by filamentous fungi of the Mucoraceae family, with the rhinocerebral form of the disease being the most common in a large case series. Uncontrolled diabetes and increased level of serum iron are regarded as the two leading predisposing factors for the development of the disease. We present a case of a 43-year-old male patient recently diagnosed with diabetes presenting with features of orbital apex syndrome and short-term memory loss. He was found to have rhino-oculocerebral mucormycosis on histopathological and radiological evaluations.

Isolation of Aspergillus spp. from the respiratory tract in critically ill patients: risk factors, clinical presentation and outcome

IntroductionOur aims were to assess risk factors, clinical features, management and outcomes in critically ill patients in whom Aspergillus spp. were isolated from respiratory secretions, using a database from a study designed to assess fungal infections.MethodsA multicentre prospective study was conducted over a 9-month period in 73 intensive care units (ICUs) and included patients with an ICU stay longer than 7 days. Tracheal aspirate and urine samples, and oropharyngeal and gastric swabs were collected and cultured each week. On admission to the ICU and at the initiation of antifungal therapy, the severity of illness was evaluated using the Acute Physiology and Chronic Health Evaluation II score. Retrospectively, isolation of Aspergillus spp. was considered to reflect colonization if the patient did not fulfil criteria for pneumonia, and infection if the patient met criteria for pulmonary infection and if the clinician in charge considered the isolation to be clinically valuable. Risk factors, antifungal use and duration of therapy were noted.ResultsOut of a total of 1756 patients, Aspergillus spp. were recovered in 36. Treatment with steroids (odds ratio = 4.5) and chronic obstructive pulmonary disease (odds ratio = 2.9) were significantly associated with Aspergillus spp. isolation in multivariate analysis. In 14 patients isolation of Aspergillus spp. was interpreted as colonization, in 20 it was interpreted as invasive aspergillosis, and two cases were not classified. The mortality rates were 50% in the colonization group and 80% in the invasive infection group. Autopsy was performed in five patients with clinically suspected infection and confirmed the diagnosis in all of these cases.ConclusionIn critically ill patients, treatment should be considered if features of pulmonary infection are present and Aspergillus spp. are isolated from respiratory secretions.

Changes in lymphocyte response to phytohaemagglutinin and serum immunosuppressive activity after thermal injury

The present study consisted of two parts. In part one, 14 cases were divided into an invasive infection group (10 cases) and a non-invasive infection group (10 cases). A total of 68 assays for lymphocyte responses to PHA stimulation were carried out. The invasive infection group showed a significantly suppressed lymphocyte response, which occurred during invasive infection but neither before nor after the infection. The extent of third-degree burns was statistically significant between these two groups (P <0·05), but no significance was found between the total body surface area burned. In part two, 18 burn patients were studied for serum immunosuppressive activity. Both invasive infection cases and non-invasive infection cases showed serum immunosuppression during the course of the study and no significant difference was found between these two groups (P >0·05). It is concluded that the extent of third-degree burn and the complicated systemic infection contribute to the impairment of lymphocyte responses to PHA stimulation, while the post-burn serum immunosuppression is unrelated to the occurrence of systemic infection.