Altered CD4+ T cell immunity in nurses occupationally exposed to viral pathogens

Pathogen exposure, including but not limited to herpesviruses, moulds the shape of the immune system, both at a basal state and in response to immune challenge. However, little is known about the impact of high exposure to other viruses on baseline immune signatures and how the immune system copes with repetitive exposures to maintain a balanced functionality. Here we investigated baseline immune signatures, including detailed T cell phenotyping, antigen-specific CD4⁺ and CD8⁺ T cell responses and cytokine profile in paediatric (PED) nurses, who have high occupational exposure to viral pathogens including varicella zoster virus (VZV) and respiratory viruses, and in neonatal intensive care unit (NICU) nurses, as a control group with infrequent occupational exposure. Our results show a lower CD4⁺ T cell response to two VZV proteins (IE62 and gE) and to tetanus toxoid (TT) in PED nurses who are cytomegalovirus (CMV)-seronegative, compared to CMV-seronegative NICU nurses, and that the decline might be more pronounced the more sustained the exposure. This decline might be due to an attrition of VZV- and TT-specific T cells as a result of the continuous pressure on the CD4⁺ T cell compartment. Moreover, our data suggest that the distinct T cell phenotypes known to be associated with CMV-seropositivity might be less prominent in PED nurses compared to NICU nurses, implying a plausible attenuating effect of occupational exposure on CMV-associated immunosenescence. Overall, this pilot study reveals an impact of occupational exposure to viral pathogens on CD4⁺ T cell immunity and supports further investigation in a larger cohort.

A tropical diabetic foot

Foot infections are a common problem and an important cause of morbidity in patients with diabetes. We report a patient with type 2 diabetes, presenting with a chronic foot wound resistant to standard care, in whom the diagnosis of eumycetoma was made through histopathological examination of a bone biopsy specimen and confirmed by polymerase chain reaction (PCR). Diagnosis and treatment of eumycetoma are reviewed. Eumycetoma caused by Madurella mycetomatis is an uncommon cause of osteomyelitis in patients with diabetes in Europe, but should be considered in patients from endemic regions when (antibacterial) therapy fails.

Long-term epidemiology of bacterial susceptibility profiles in adults suffering from febrile neutropenia with hematologic malignancy after antibiotic change

Objective:

The aim of this study was to investigate the epidemiology and antibiotic susceptibility profiles of isolated bacterial organisms in relation to empiric treatment of neutropenic fever over a 15-year period.

Methods:

All patients with or at risk for febrile neutropenia and treated in the hematology ward of the Antwerp University Hospital during 1994–2008 were prospectively included. Skin, blood, and urine cultures were taken. Oral quinolone prophylaxis was started in patients with neutropenia without fever. Empiric starting therapy consisted of amikacin in combination with cefepime.

Results:

A total of 3624 bacteria were isolated. The most common pathogens were coagulase-negative Staphylococci (46%), followed by Escherichia coli (25%), Enterobacteriaceae (15.6%), Staphylococcus aureus (7.2%), and Pseudomonas aeruginosa (3.8%). The balance between Gram-positive and Gram-negative bacteria remained stable, with a majority of Gram-positive bacteria. A shift from oxacillin-sensitive to oxacillin-resistant coagulase-negative Staphylococci was observed. Regarding susceptibility patterns, no vancomycin resistance was detected in coagulase-negative Staphylococci or in S. aureus. The E. coli susceptibility rates remained stable. However, 66% of bloodstream infections were ciprofloxacin-resistant. A reduced susceptibility of P. aeruginosa strains to meropenem was noticed.

Conclusions:

Improvement in antibiotic susceptibility of inducible Enterobacteriaceae following a switch of empiric antibiotic therapy was maintained 15 years after starting the latter treatment. Further improvement in antibiotic susceptibility of these bacteria to ceftazidime was observed, but continuous vigilance is warranted.

A series of five adult cases of respiratory syncytial virus-related acute respiratory distress syndrome

Respiratory syncytial virus is a common cause of respiratory tract disease in children, predominantly presenting with mild symptoms. We present five cases of respiratory syncytial virus infection of the lower respiratory tract in immunocompromised adults suffering from severe respiratory insufficiency leading to bilateral pneumonia and fulfilling the criteria for acute respiratory distress syndrome. Respiratory syncytial virus was cultured as the only pathogen in the bronchoalveolar lavage fluid in four of these patients. Despite various therapeutic interventions, only one patient survived. Respiratory syncytial virus was implicated as a direct cause of respiratory failure. Respiratory syncytial virus may be an underestimated cause of severe respiratory failure and acute respiratory distress syndrome in the immunocompromised adult admitted to the intensive care unit.

Study of the environmental effect of a commercial wound cleanser used with different mechanical forces

Important improvements have been made in wound care over the last decade. However, few data are available on the influence that these have outside their intended use. This study aimed to clarify the effects of the use of wound cleansers on bacterial contamination of the immediate surroundings. Little evidence was found from either laboratory or clinical settings that wound-derived micro-organisms become airborne during wound cleansing. Bacterial dispersion around wounds may be attributed to general activity rather than wound cleansing. If simple precautions are taken, risks for personnel and patients in hospitals and consultation rooms during wound cleansing can be minimized.

High-dose cefepime as an alternative treatment for infections caused by TEM-24 ESBL-producing Enterobacter aerogenes in severely-ill patients

This study evaluated retrospectively the efficacy of treatment with cefepime vs. a carbapenem, in combination with amikacin or ciprofloxacin, for seriously-ill patients infected with ESBL-producing Enterobacter aerogenes who were admitted to an intensive care unit. Forty-four episodes of infection were investigated in 43 patients: 21 treated with cefepime; 23 with a carbapenem. The two treatment groups did not differ statistically in terms of age, APACHE II scores, and infection sites, but the average duration of antibiotic exposure was significantly shorter in the cefepime group (8.5 days vs. 11.4 days; p 0.04). Clinical improvement was seen in 62% of patients receiving cefepime vs. 70% of patients receiving a carbapenem (p 0.59). Bacteriological eradication was achieved in 14% of patients receiving cefepime vs. 22% of patients receiving a carbapenem (p 0.76). The 30-day mortality rates related to infection were 33% in the cefepime group and 26% in the carbapenem group (p 0.44). Thus, outcome parameters did not differ significantly between the two groups. Nevertheless, a statistically significant increase in failure to eradicate ESBL-producing E. aerogenes was observed as the MICs of cefepime rose (p 0.017). Pulsed-field gel electrophoresis revealed three distinct clones, but one predominant clone harbouring the bla(TEM-24) gene was associated with most (42/44) of the episodes of infection. It was concluded that cefepime may be an alternative agent for therapy of severe infections caused by TEM-24 ESBL-producing E. aerogenes, although further studies are required to confirm these observations.

A prospective study on factors influencing aspergillus spore load in the air during renovation works in a neonatal intensive care unit

The relationship between air contamination (cfu/m(3)) with fungal spores, especially Aspergillus spp., in three renovation areas of a neonatal intensive care unit (NICU) and colonization and infection rates in a high care area (HC) equipped with high efficiency particulate air (HEPA) filtration and a high pressure system, was evaluated. Data on the type and site of renovation works, outdoor meteorological conditions, patient crowding and nasopharyngeal colonization rate were collected. Factors not associated with Aspergillus spp. concentration were outdoor temperature, air pressure, wind speed, humidity, rainfall, patient density in the NICU, renovation works in the administrative area and in the isolation rooms. Multivariate analysis revealed that renovation works and air concentration of Aspergillus spp. spores in the medium care area (MC) resulted in a significant increase of the concentration in the HC of the NICU. The use of a mobile HEPA air filtration system (MedicCleanAir(R)Forte, Willebroek, Belgium) caused a significant decrease in the Aspergillus spp. concentration. There was no relationship between Aspergillus spp. air concentration and nasopharyngeal colonization in the neonates. Invasive aspergillosis did not occur during the renovation. This study highlights the importance of optimal physical barriers and air filtration to decrease airborne fungal spores in high-risk units during renovation works. The value of patient surveillance and environmental air sampling is questionable since no relationship was found between air contamination and colonization in patients.

Rapid detection of methicillin resistance in coagulase-negative staphylococci by commercially available fluorescence test

A commercially available fluorescence test (Crystal MRSA ID System; BBL) for the rapid detection of methicillin resistance in Staphylococcus aureus was evaluated for the detection of methicillin resistance in coagulase-negative staphylococci. The assay was compared with the agar dilution method and mecA detection by PCR. Provided that one uses an inoculum equivalent to a no. 2 McFarland standard instead of a no. 0.5 McFarland standard, which is used for S. aureus, the Crystal MRSA ID System detects methicillin resistance among coagulase-negative staphylococci with sensitivity, specificity, and positive and negative predictive values of 98.5, 95.4, 96.3, and 98.1%, respectively.