Viral and bacterial aetiologies of male urethritis: findings of a high prevalence of Epstein-Barr virus.

Male urethritis is one of the most common sexually transmitted infections (STIs). However, the aetiology is still unclear in many cases. In this study the prevalences of Epstein-Barr virus (EBV), herpes simplex virus type 1 (HSV-1), HSV-2, cytomegalovirus (CMV), adenovirus, Chlamydia trachomatis, Mycoplasma genitalium and Ureaplasma urealyticum (including subtyping) were investigated. Samples from 112 male STI attendants with microscopically verified urethritis and from a control group of 103 men without clinical or microscopic signs of urethritis were analysed. Prevalences in the urethritis group compared with the controls were as follows: EBV 21%, 6% (P < 0.01); C. trachomatis 15%, 3% (P < 0.01); M. genitalium 6%, 1% (P = 0.067) and U. urealyticum 10%, 10% (ns). The results for HSV-1, HSV-2, CMV and adenovirus were negative in patients, and therefore not analysed in the controls. EBV was shown to be an independent predictor of urethritis and may play a role in its pathogenesis.

A large Escherichia coli O157 outbreak in Sweden associated with locally produced lettuce.

In 2005 a large outbreak of verotoxin-producing Escherichia coli (VTEC) occurred in Sweden. Cases were interviewed and cohort and case-control studies were conducted. Microbiological investigations were performed using polymerase chain reaction (PCR) to detect the Shiga-like toxin (Stx) genes followed by cultivation and pulsed-field gel electrophoresis. A total of 135 cases were recorded, including 11 cases of hemolytic uremic syndrome. The epidemiological investigations implicated lettuce as the most likely source of the outbreak, with an OR of 13.0 (CI 2.94-57.5) in the case-control study. The lettuce was irrigated by water from a small stream, and water samples were positive for Stx 2 by PCR. The identical VTEC O157 Stx 2 positive strain was isolated from the cases and in cattle at a farm upstream from the irrigation point. An active surveillance and reporting system was crucial and cooperation between all involved parties was essential for quickly identifying the cause of this outbreak. Handling of fresh greens from farm to table must be improved to minimize the risk of contamination.

Comparison of broad-range bacterial PCR and culture of cerebrospinal fluid for diagnosis of community-acquired bacterial meningitis.

Appropriate, rapid and reliable laboratory tests are essential for the diagnosis and optimal antibiotic therapy of acute bacterial meningitis. Broad-range bacterial PCR, combined with DNA sequencing, was compared with culture-based methods for examining cerebrospinal fluid (CSF) samples from patients with suspected meningitis. In total, 345 CSF specimens from 345 patients were analysed, with acute community-acquired bacterial meningitis being diagnosed in 74 patients. The CSF of 25 patients was positive by both PCR and culture; 26 patients had CSF specimens positive by PCR only, and 14 patients had specimens positive by culture only. The sensitivity of PCR and culture for clinically relevant meningitis was 59% (44/74) and 43% (32/74), respectively, while the specificity was 97% (264/271) and 97% (264/271), respectively. The commonest bacterial rRNA gene sequences detected by PCR only were those of Streptococcus pneumoniae and Neisseria meningitidis (n = 12). PCR failed to detect the bacterial rRNA gene in seven specimens from patients with symptoms compatible with acute bacterial meningitis. Overall, the results demonstrated that PCR in conjunction with sequencing may be a useful tool in the diagnosis of bacterial meningitis. PCR is particularly useful for analysing CSF from patients who have been treated with antibiotics before lumbar puncture.

Virulence genes in verocytotoxigenic Escherichia coli strains isolated from humans and cattle.

Verocytotoxigenic Escherichia coli (VTEC) causing diarrhoea, haemorrhagic colitis and haemolytic-uremic syndrome usually have additional traits such as the adhesin intimin and a large plasmid that seems to increase virulence. There are, however, isolates of VTEC causing serious symptoms that do not harbour these traits. In the present study we have used PCR with primers detecting adhesin genes other than eaeA, namely fimA, papC, sfaD/sfaE and daaE. We have also used PCR to detect the genes hlyA and iutA that besides the plasmid-borne gene E-hly possibly support the bacterial access to iron. The aim of the study was to identify and compare the presence of virulence genes in VTEC isolates of human and cattle origin. The main finding was that the absence of E-hly might be compensated for by the gene iutA coding for aerobactin or hlyA coding for alpha-haemolysin as 94% of the human VTEC isolates had at least one of these genes. Interestingly, only 45% of VTEC isolated from cattle had any of these genes. We propose that this might be the reason for the relatively low incidence of symptomatic VTEC infections among humans in relation to the high number of VTEC among cattle.

Genotyping of Pseudomonas aeruginosa reveals high diversity, stability over time and good outcome of eradication.

BACKGROUND: Genotyping of Pseudomonas aeruginosa (P.a) is used for surveillance at our CF clinic. METHODS: P.a from 1999 to 2012 were analysed, using pulsed-field gel electrophoresis (PFGE) and multiple-locus variable number of tandem repeats analysis (MLVA). RESULTS: Among 232 isolates from 104 patients, we identified 78 unique strains, of which 56 were isolated from individual patients. The B-clone was isolated from 13 patients and the camp transmission clone J-strains from 8 patients at the start of the study. There was no indication of transmission within the clinic. PFGE and MLVA clone identification was in 91% agreement. For patients who provided more than 2 P.a isolates, similar strains were identified over time for 45/49 chronically- and for 6/16 intermittently-colonized patients despite, periods of no detectable P.a after eradication therapy. CONCLUSIONS: Analyses revealed high genotypic diversity, acceptable outcome of eradication therapy and no indication of cross-infection at the CF centre.

Plasmids and serogroups in Campylobacter jejuni.

For epidemiological purposes identification of Campylobacter strains is usually based on surface antigen characteristics. Two different systems, one for heat-stable (HS) and one for heat-labile (HL) antigen have dominated. In earlier studies we found a great variability in the two antigen systems. The aim of the present investigation was to analyse the frequency of plasmids in Campylobacter strains in the light of their possible use as an epidemiological tool as well as the relation between the presence of plasmids and surface antigens (HS and HL). Two hundred and forty-two strains from the same number of patients with diarrhea were analysed. In 70 (28.9%) plasmid(s) were found, in general one or two. Most of the plasmids were found in the molecular weight interval between 21-40 Md. There was no relation between the presence or size of plasmids and serogroup. We conclude that plasmid determination can be used as a complement to serotyping in epidemiological studies.

Occurrence and treatment of Mycoplasma genitalium in patients visiting STD clinics in Sweden.

Two hundred and thirty-three men and 85 women visiting STD clinics in western Sweden between April 1997 and March 1998 were examined for Mycoplasma genitalium and Chlamydia trachomatis. The bacteria were identified by the polymerase chain reaction (PCR) technique. Three women (3.5%) and 18 men (7%) were positive for M. genitalium. Seventeen (14%) of the 115 men with urethritis were infected but only one of the men was without urethritis. After treatment with tetracyclines for 10 days, one woman and 8 of the 13 men still harboured M. genitalium. M. genitalium-infected men did not have more life-time partners than other men visiting STD clinics. More men positive for M. genitalium gave a history of previous urethritis but the difference was not significant.

Shift of CTX-M genotypes has determined the increased prevalence of extended-spectrum ß-lactamase-producing Escherichia coli in south-western Sweden.

The prevalence of Escherichia coli producing extended-spectrum ß-lactamases (ESBLs) markedly increased during 2004-2008 in south-western Sweden, with a greater increase in urinary isolates in hospitals (0.2-2.5%) than in the community (0.2-1.6%). ESBLs of genotype CTX-M predominated, with a significant (p <0.02) shift from the CTX-M-9 to CTX-M-1 phylogroup occurring among urinary ESBL-producing E. coli isolated early (n = 41) as compared with late (n = 221) in the study period. The increase in ESBL-producing E. coli was polyclonal, and only partly attributable to an increase (0-24%) in the number of O25b-ST131 isolates carrying CTX-M-15. The increase was prominent in men and in elderly patients, and warrants continued surveillance.

Optimization of the detection of microbes in blood from immunocompromised patients with haematological malignancies.

The present study aimed to improve the rate of detection of blood-borne microbes by using PCRs with pan-bacterial and Candida specificity. Seventeen per cent of the blood samples (n=178) collected from 107 febrile patients with haematological malignancies were positive using standard culture (BacT/Alert system). Candida PCR was positive in 12 patients, only one of whom scored culture-positive. Bacterial PCR using fresh blood samples was often negative, but the detection rate increased when the blood was pre-incubated for 2 days. These data indicate that PCR assays might be a complement for the detection of blood-borne opportunists in immunocompromised haematology patients.

Improved microbiological techniques using the polymerase chain reaction and pulsed-field gel electrophoresis for diagnosis and follow-up of enterohaemorrhagic Escherichia coli infection.

The aims of the present investigation were to evaluate the microbiological diagnostic procedures, especially polymerase chain reaction (PCR) versus culture and seroagglutination, in relation to the clinical features of enterohaemorrhagic Escherichia coli (EHEC) infection and to study the status of EHEC in the western part of Sweden. During 1997 and 1998, stool specimens from 3,948 patients were analysed by PCR for the presence of EHEC with verotoxin (VT)1- and/or VT2-producing DNA sequences. The stool specimens were also cultured for Escherichia coli O157:H7, Salmonella, Campylobacter, Shigella and Yersinia. Fifty-five patients were positive by PCR. Thirty-nine patients were positive for EHEC by PCR and culture. Of these, 29 were infected with EHEC serogroup O157:H7 strains. All EHEC isolates were analysed by pulsed-field gel electrophoresis (PFGE); 17 different clones were identified. Studies on the duration of the presence of EHEC in the gut showed that EHEC often disappears rather quickly, i.e. within 2 weeks. In one patient, however, EHEC remained for several months. In conclusion, PCR, rather than culture and agglutination, should be the method of choice for microbiological diagnosis of EHEC infection. PCR is more sensitive than culture for detecting EHEC in the gut.

Evaluation of PCR for diagnosis of Bordetella pertussis and Bordetella parapertussis infections.

PCR, using primers Plp1 and Plp2, was evaluated for the detection of DNA from Bordetella pertussis in bacterial strains and in nasopharyngeal samples from patients with a cough lasting at least 7 days. The assay could detect DNA from 6 CFU of B. pertussis/10 microl of sample. Results of the PCR assay were compared with those of cultures, a determination of serum antibodies against pertussis toxin and filamentous hemagglutinin, and a clinical evaluation of 2,442 coughing episodes. The overall sensitivity of PCR was 65% (623 of 956), which was higher than the sensitivity of cultures (58%) (P < 0.001). Factors influencing the sensitivity of PCR were the interval between the onset of symptoms and sampling and the vaccination status of the patient. The specificity of PCR was 98% (1,451 of 1,486). The positive and negative predictive values were 95 and 81%, respectively. Parapertussis PCR, using primers BPPA and BPPZ, was positive in 11 of 18 culture-positive cases and was confirmed by serology in another 4 cases. In conclusion, PCR is a valuable complement to cultures and can probably replace cultures for diagnosis of B. pertussis and Bordetella parapertussis infections.

EHEC outbreak among staff at a children's hospital--use of PCR for verocytotoxin detection and PFGE for epidemiological investigation.

This is the first report of a major foodborne outbreak of enterohaemorrhagic Escherichia coli (EHEC) in Sweden. It occurred among the nursing staff at a children's hospital with approximately 1600 employees. Contaminated lettuce was the most likely source of infection. Nine persons were culture-positive for Escherichia coli (E. coli) O157 and verocytotoxin-positive by PCR and a further two were verocytotoxin-positive by PCR only. All 11 EHEC-positive individuals had attended a party for approximately 250 staff members, which was held at the hospital. In a questionnaire 37 persons stated that they had symptoms consistent with EHEC infection during the weeks after the party. There was no evidence of secondary transmission from staff to patients. The value of PCR as a sensitive and fast method for diagnosis is discussed in this paper. Pulsed-field gel electrophoresis (PFGE) was used to ascertain that staff members were infected by the same clone, and that two patients with E. coli O157 infection were not.