Detection of multiple respiratory pathogens during primary respiratory infection: nasal swab versus nasopharyngeal aspirate using real-time polymerase chain reactionMeerhoff, T.; Houben, M.; Coenjaerts, F.; Kimpen, J.; Hofland, R.; Schellevis, F.; Bont, L.
doi: 10.1007/s10096-009-0865-7pmid: 20111881
In this study, we present the multiple detection of respiratory viruses in infants during primary respiratory illness, investigate the sensitivity of nasal swabs and nasopharyngeal aspirates, and assess whether patient characteristics and viral load played a role in the sensitivity. Healthy infants were included at signs of first respiratory tract infection. Paired nasopharyngeal aspirates and nasal swabs were collected. Real-time polymerase chain reaction (PCR) was carried out for 11 respiratory pathogens. Paired nasopharyngeal aspirates and nasal swabs were collected in 98 infants. Rhinovirus (n = 67) and respiratory syncytial virus (n = 39) were the most frequently detected. Co-infection occurred in 48% (n = 45) of the infants. The sensitivity of the nasal swab was lower than the nasopharyngeal aspirate, in particular, for respiratory syncytial virus (51% vs. 100%) and rhinovirus (75% vs. 97%). The sensitivity of the nasal swab was strongly determined by the cycle threshold (CT) value (p < 0.001). The sensitivity of the swab for respiratory syncytial virus, but not rhinovirus, was 100% in children with severe symptoms (score ≥11). It is concluded that, for community-based studies and surveillance purposes, the nasal swab can be used, though the sensitivity is lower than the aspirate, in particular, for the detection of mild cases of respiratory syncytial virus (RSV) infection.
Characterization of the best anatomical sites in screening for methicillin-resistant Staphylococcus aureus colonizationBitterman, Y.; Laor, A.; Itzhaki, S.; Weber, G.
doi: 10.1007/s10096-009-0869-3pmid: 20111880
The purpose of this study was to identify differences in the sensitivity of anatomical sites sampling for methicillin-resistant Staphylococcus aureus (MRSA) colonization related to age, gender, clinical situation, and acquisition source as a base for screening protocols. We used a database that included all MRSA-positive cultures (Carmel Medical Center, 2003–2006) taken from nares, throat, perineum, and infection sites. The study population of 597 patients was divided into: “screening sample” (SS), which were cases of routine screening, and “clinical diagnostic sample” (CDS), which were patients with concurrent MRSA infection. MRSA acquisition sources were classified as internal medicine, surgical, referral patients, or intensive care unit (ICU). CDS patients were older than SS patients (median age 78 vs. 74 years, p = 0.0002), more commonly throat colonized (47.5% vs. 31.8%, p = 0.0001), and colonized in more multiple sites (65.7% vs. 43.3% were colonized in three sites in the CDS and SS groups, respectively, p < 0.001) than SS patients. In the SS, group throat colonization was higher in internal medicine wards than in the ICU (odds ratio [OR] = 3.98, p < 0.0001). In the CDS group, perineal colonization was more common in referral patients than in the ICU (OR = 4.52, p < 0.05). Patient age was the most influential factor on nares and multiple sites colonization in the SS and CDS groups, respectively. Our data support multiple sites sampling. Throat cultures are crucial in MRSA-infected patients and internal medicine ward patients. Multiple body sites colonization is more likely in older or MRSA-infected patients, affecting decisions regarding eradication using topical antibiotics.
Management of post-splenectomy patients in the NetherlandsLammers, A.; Veninga, D.; Lombarts, M.; Hoekstra, J.; Speelman, P.
doi: 10.1007/s10096-009-0870-xpmid: 20094896
After splenectomy, patients are at increased risk of sepsis with considerable mortality. The risk of sepsis can be reduced by immunising these patients and by prescribing antibiotic prophylaxis. The purpose of our study was to determine compliance with the international standards for the management of splenectomised patients in the Netherlands by investigating: (i) vaccination rates, (ii) the prescription of antibiotics and (iii) information in discharge letters. A retrospective review of the medical records and discharge correspondence of 609 splenectomy patients from 1997 to 2008 was performed. Data were collected from 28 hospitals. Adherence to vaccination guidelines and the prescription of antibiotics were assessed. It was found that 85.4% of post-splenectomy patients received pneumococcal vaccination, 39.4% received Haemophilus influenzae type B and 32.3% received meningococcal group C vaccination. Also, 12.4% of patients were discharged on prophylactic antibiotics. In less than 25% of cases were adequate recommendations regarding post-splenectomy management given to the general practitioner (GP). In the Netherlands, compliance with recommendations for the management of patients after splenectomy is insufficient. Fifteen percent of patients do not receive vaccination against pneumococci and the majority of patients do not receive antibiotic prophylaxis. The development and implementation of a national guideline for splenectomised patients is urgently required.
In vitro time-kill activities of ciprofloxacin alone and in combination with the iron chelator deferasirox against Vibrio vulnificusNeupane, G.; Kim, D.-M.
doi: 10.1007/s10096-010-0875-5pmid: 20127132
Iron plays a major role in the growth and virulence of ferrophilic organisms like Vibrio vulnificus. People who reside in the coastal areas with raw fish eating habits have a high risk of Vibrio infection and aggressive therapy can only reduce their mortality. We investigated the in vitro efficacy of ciprofloxacin, a bactericidal drug used in V. vulnificus patients, and the orally active iron chelator deferasirox against V. vulnificus infection. We performed in vitro time-kill studies on two ATCC strains and one clinical isolate of V. vulnificus collected from a patient admitted to Chosun University Hospital with either ciprofloxacin or iron chelator deferasirox alone and the two drugs in combination. The combination of an iron chelator plus an antibiotic creates a novel form of synergism at 24 h. The antimicrobial effect of deferasirox may be ascribed to its ability to deplete iron that would otherwise be used for bacterial growth. Combination therapy with ciprofloxacin plus deferasirox has potential clinical application by lowering the iron availability against a ferrophilic organism like V. vulnificus infections.
Comparison of microscopy, two xenic culture techniques, conventional and real-time PCR for the detection of Dientamoeba fragilis in clinical stool samplesStark, D.; Barratt, J.; Roberts, T.; Marriott, D.; Harkness, J.; Ellis, J.
doi: 10.1007/s10096-010-0876-4pmid: 20155433
Dientamoeba fragilis is a pathogenic protozoan parasite that is notoriously difficult to diagnose. The aim of this study was to determine the gold standard for laboratory detection of D. fragilis. A total of 650 human faecal samples were included in the study. All specimens underwent the following: microscopy using a permanent stain (modified iron-haematoxylin), culture using a modified Boeck and Drbohlav’s medium (MBD) and TYGM-9, a conventional polymerase chain reaction (PCR) and a real-time PCR (RT-PCR). The overall prevalence of D. fragilis in the study population was 5.4% (35/650). RT-PCR detected 35 isolates, conventional PCR detected 15 isolates, MBD culture detected 14 isolates, TYGM-9 detected ten isolates, while microscopy detected 12 isolates. RT-PCR detected an additional 15 positive samples compared to the other diagnostic methods, all of which were confirmed by sequencing. When all methods were compared to each other, RT-PCR showed a sensitivity and specificity of 100 and 100%, conventional PCR 42.9 and 100%, MBD culture 40 and 100%, TYGM-9 culture 28.6 and 100%, and microscopy 34.3 and 99%, respectively. These results show that RT-PCR is the diagnostic method of choice for the detection of D. fragilis in clinical samples and, as such, should be considered as the gold standard for diagnosis.