Peter M. Schneeberger

Clinical relevance of the cagA, vacA, and iceA status of Helicobacter pylori.

BACKGROUND & AIMS Clinical outcome of Helicobacter pylori infection may be associated with specific virulence-associated bacterial genotypes. The aim of this study was to assess the relationships between H. pylori cagA, vacA, and iceA status and severity of disease. METHODS Gastric biopsy specimens from 94 patients in The Netherlands were analyzed by polymerase chain reaction and reverse hybridization. RESULTS cagA was present in 63 (67%) of 94 cases and was associated with peptic ulcer disease (P = 0.0019). vacA geno-types s1a/m1, s1b/m2, s1b/m1, s1b/m2, and s2/m2 were found in 36.2%, 23.4%, 2.1%, 5.3%, and 20.2%, respectively. Ten isolates (10.6%) contained multiple vacA genotypes. The presence of peptic ulcers was associated with type s1 strains (P = 0.0006) but not with the m type (P = 0.2035). cagA and vacA s1 were strongly associated (P < 10(-5)). iceA1 was found in 53 (56.4%) and iceA2 in 25 (26.6%) of the 94 cases. In 14 isolates (14.9%), both iceA alleles were found, and 2 (2.1%) were negative for both iceA1 and iceA2. iceA1 was also associated with peptic ulcer disease (P = 0.0042). The iceA allelic type was independent of the cagA and vacA status. CONCLUSIONS vacA s1, cagA, and iceA1 are markers of H. pylori strains that are more likely to lead to ulcer disease.

Geographic Distribution of vacA Allelic Types of Helicobacter pylori

BACKGROUND & AIMS Distinct allelic types of Helicobacter pylori vacA have been defined. The geographic distribution of vacA alleles and cagA was assessed in this study. METHODS A total of 735 cultures from patients in 24 countries were analyzed by polymerase chain reaction and reverse hybridization on a line probe assay (LiPA). RESULTS In 124 (16.9%) of the 735 cultures, multiple vacA genotypes were detected, permitting analysis of 611 strains. In Europe, a distribution gradient of s1 subtypes was observed. In northern and eastern Europe, 89% were subtype s1a. s1a and s1b were equally present in France and Italy, whereas in Spain and Portugal 89% of strains were subtype s1b. s1a and s1b were approximately equally prevalent in North America. In Central and South America, virtually all s1 strains were subtype s1b. Subtype s1c was observed in 77% of the s1 isolates from East Asia. m1 and m2a have equal presence, except on the Iberian peninsula and in Central and South America, where m1 (86.2%) is more prevalent than m2 (13.8%). Subtype m2b was found exclusively among East Asian s1c strains. In all parts of the world, vacA s1/cagA-positive genotypes were associated with peptic ulcer disease (P < 0.001). CONCLUSIONS These data indicate a geographic distribution of H. pylori genotypes and aid in understanding the relationship of H. pylori with disease.

The 2007-2010 Q fever epidemic in The Netherlands: characteristics of notified acute Q fever patients and the association with dairy goat farming.

We describe the Q fever epidemic in the Netherlands with emphasis on the epidemiological characteristics of acute Q fever patients and the association with veterinary factors. Data from 3264 notifications for acute Q fever in the period from 2007 through 2009 were analysed. The patients most affected were men, smokers and persons aged 40–60 years. Pneumonia was the most common clinical presentation (62% in 2007 and 2008). Only 3.2% of the patients were working in the agriculture sector and 0.5% in the meat-processing industry including abattoirs. Dairy goat farms with Coxiella burnetii-induced abortion waves were mainly located in the same area where human cases occurred. Airborne transmission of contaminated dust particles from commercial dairy goat farms in densely populated areas has probably caused this epidemic. In 2010, there was a sharp decline in the number of notified cases following the implementation of control measures on dairy goat and sheep farms such as vaccination, hygiene measures and culling of pregnant animals on infected farms. In combination with a rise in the human population with antibodies against C. burnetii, these have most likely ended the outbreak. Development of chronic Q fever in infected patients remains an important problem for years to come.

The use of a geographic information system to identify a dairy goat farm as the most likely source of an urban Q-fever outbreak

BackgroundA Q-fever outbreak occurred in an urban area in the south of the Netherlands in May 2008. The distribution and timing of cases suggested a common source. We studied the spatial relationship between the residence locations of human cases and nearby small ruminant farms, of which one dairy goat farm had experienced abortions due to Q-fever since mid April 2008. A generic geographic information system (GIS) was used to develop a method for source detection in the still evolving major epidemic of Q-fever in the Netherlands.MethodsAll notified Q-fever cases in the area were interviewed. Postal codes of cases and of small ruminant farms (size >40 animals) located within 5 kilometres of the cluster area were geo-referenced as point locations in a GIS-model. For each farm, attack rates and relative risks were calculated for 5 concentric zones adding 1 kilometre at a time, using the 5-10 kilometres zone as reference. These data were linked to the results of veterinary investigations.ResultsPersons living within 2 kilometres of an affected dairy goat farm (>400 animals) had a much higher risk for Q-fever than those living more than 5 kilometres away (Relative risk 31.1 [95% CI 16.4-59.1]).ConclusionsThe study supported the hypothesis that a single dairy goat farm was the source of the human outbreak. GIS-based attack rate analysis is a promising tool for source detection in outbreaks of human Q-fever.

Real-Time PCR with Serum Samples Is Indispensable for Early Diagnosis of Acute Q Fever

ABSTRACT The worlds largest Q fever outbreak is ongoing in The Netherlands with around 3,000 confirmed cases since the first half of 2007. Increased awareness has resulted in early referral of patients for diagnostics. An important drawback to serological diagnosis of acute Q fever is the lag phase in antibody response. Therefore, we evaluated the performance of a real-time PCR for detection of Coxiella burnetii DNA using serum samples from patients with acute Q fever. PCR, targeting IS1111, was retrospectively performed on acute-phase and follow-up convalescent-phase serum samples from 65 patients with acute Q fever as diagnosed by immunofluorescence assay. The results obtained by PCR were related to disease stage as defined by subsequent appearance of phase II IgM, phase II IgG, phase I IgM, and phase I IgG (IgM-II, IgG-II, IgM-I, and IgG-I, respectively) antibodies and time since onset of disease. In addition, we analyzed seronegative acute-phase serum samples from patients with inconclusive Q fever serology, because no convalescent-phase serum samples were available. PCR was scored positive in 49/50 (98%) seronegative sera, 9/10 (90%) sera with isolated IgM-II antibodies, 3/13 (23%) sera with IgM-II/IgG-II antibodies, 2/41 (5%) sera with IgM-II/IgG-II/IgM-I antibodies, 0/15 (0%) sera with IgM-II/IgG-II/IgM-I/IgG-I antibodies, and 0/1 (0%) serum sample with IgM-II/IgG-II/IgG-I antibodies. The latest time point after onset of disease in which C. burnetii DNA could be detected was at day 17. In patients with inconclusive Q fever serology, PCR was positive in 5/50 (10%) cases. We conclude that real-time PCR with serum samples is indispensable for early diagnosis of acute Q fever. C. burnetii DNA becomes undetectable in serum as the serological response develops.

Investigation of a Q fever outbreak in a rural area of The Netherlands.

A Q fever outbreak occurred in the southeast of The Netherlands in spring and summer 2007. Risk factors for the acquisition of a recent Coxiella burnetii infection were studied. In total, 696 inhabitants in the cluster area were invited to complete a questionnaire and provide a blood sample for serological testing of IgG and IgM phases I and II antibodies against C. burnetii, in order to recruit seronegative controls for a case-control study. Questionnaires were also sent to 35 previously identified clinical cases. Limited environmental sampling focused on two goat farms in the area. Living in the east of the cluster area, in which a positive goat farm, cattle and small ruminants were situated, smoking and contact with agricultural products were associated with a recent infection. Information leaflets were distributed on a large scale to ruminant farms, including hygiene measures to reduce the risk of spread between animals and to humans.

The Prevalence and Incidence of Hepatitis C Virus Infections among Dialysis Patients in The Netherlands: A Nationwide Prospective Study

A nationwide prospective survey on hepatitis C virus (HCV) infections among dialysis patients in The Netherlands was performed. Patients were recruited from 34 dialysis centers and were tested for antibodies and HCV RNA in 1995 and 1997. Seronegative serum samples were analyzed by reverse-transcriptase polymerase chain reaction in pools. HCV-RNA-positive serum samples were genotyped and were partly sequenced. In the first and second rounds, 67 (2.9%) of 2281 and 76 (3.4%) of 2286 patients were HCV positive, respectively. Of 960 patients with paired serum samples, 35 were HCV positive in both rounds, and 9 HCV-positive cases were newly identified in the second round. The incidence of HCV infection was 0.5 per 100 dialysis years. Phylogenetic analysis revealed clustered sequences that indicated nosocomial transmission. Sixty percent of HCV infections, however, can be attributed to 4 interdependent risk factors (i.e., hemodialysis before 1992, kidney transplantation before 1994, and birth or dialysis in a foreign country). In conclusion, the prevalence of HCV infections in The Netherlands does not decline, and transmission within dialysis units continues. Adequate screening of HCV infections and strict enforcement of universal infection control practices are required.

Alpha-hemolytic streptococci : a major pathogen of iatrogenic meningitis following lumbar puncture. Case reports and a review of the literature

SummaryIatrogenic meningitis following lumbar puncture is a rare complication of myelography, spinal anesthesia, intrathecal chemotherapy, and epidural anesthesia. Sporadic cases and clusters of iatrogenic meningitis have been reported after intrathecal therapy, but most incidental cases are reported after myelography. Four cases of iatrogenic meningitis caused by viridans streptococci and a review of the literature are presented here. Observations and a case control study implicated a single anesthesiologist as the source. Probable cause of this cluster is non-observance of infection control measures as to the routine wearing of masks during the procedure. New infection control guidelines were implemented. A review of the literature on iatrogenic meningitis is given. Viridans streptococci have emerged as major pathogens of this complication. These findings underline the need to wear face masks since these bacteria are commensals of the oral cavity.ZusammenfassungEine iatrogene Meningitis nach Lumbalpunktion ist eine seltene Komplikation bei Myelographie, intrathekaler Chemotherapie und spinaler, sowie epiduraler Anaesthesie. Kasuistiken von Fällen von iatrogener Meningitis sind nach intrathekaler Applikation beschrieben, kommen aber am häufigsten nach Myelographie vor. Wir berichten über vier Patienten mit iatrogener Meningitis verursacht durch viridans Streptokokken und geben eine Übersicht über die Literatur. Beobachtungen und eine Fall-Kontroll-Studie verwiesen auf einen Anaesthesisten als Verursacher der Infektionen. Der wahrscheinliche Grund der Häufung der Fälle war das Nichteinhalten von Hygienevorschriften, insbesondere das Tragen eines Mund-/Nasenschutzes. Neue Hygienevorschriften wurden eingeführt. Auch aus der Literaturübersicht gehen vergrünende Streptokokken als einer der wichtigsten Erreger der iatrogenen Meningitis hervor. Da diese Mikroorganismen zur Normalflora des Nasen-Rachenraumes gehören, empfehlen wir das Tragen eines Mund-Nasenschutzes.

Coxiella burnetii infection among blood donors during the 2009 Q-fever outbreak in The Netherlands.

BACKGROUND: In 2007, 2008, and 2009 outbreaks of Q‐fever occurred in the Netherlands with increasing magnitude. The 2009 outbreak with 2354 reported cases is the largest human Q‐fever outbreak ever recorded. To assess the extent of infection and the safety of donated blood, we tested local blood donations for presence of Coxiella burnetii antibodies and DNA.

Follow-up of 686 patients with acute Q fever and detection of chronic infection

BACKGROUND Recent outbreaks in the Netherlands allowed for laboratory follow-up of a large series of patients with acute Q fever and for evaluation of test algorithms to detect chronic Q fever, a condition with considerable morbidity and mortality. METHODS For 686 patients with acute Q fever, IgG antibodies to Coxiella burnetii were determined using an immunofluorescence assay at 3, 6, and 12 months of follow-up. Polymerase chain reaction (PCR) was performed after 12 months and on earlier serum samples with an IgG phase I antibody titer ≥ 1:1024. RESULTS In 43% of patients, the IgG phase II antibody titers remained high (≥ 1:1024) at 3, 6, and 12 months of follow-up. Three months after acute Q fever, 14% of the patients had an IgG phase I titer ≥ 1:1024, which became negative later in 81%. IgG phase I antibody titers were rarely higher than phase II titers. Eleven cases of chronic Q fever were identified on the basis of serological profile, PCR results, and clinical presentation. Six of these patients were known to have clinical risk factors at the time of acute Q fever. In a comparison of various serological algorithms, IgG phase I titer ≥ 1:1024 at 6 months had the most favorable sensitivity and positive predictive value for the detection of chronic Q fever. CONCLUSIONS The wide variation of serological and PCR results during the follow-up of acute Q fever implies that the diagnosis of chronic Q fever, necessitating long-term antibiotic treatment, must be based primarily on clinical grounds. Different serological follow-up strategies are needed for patients with and without known risk factors for chronic Q fever.