Invasive disease caused by Haemophilus influenzae in Sweden 1997-2009; evidence of increasing incidence and clinical burden of non-type b strains.

Introduction of a conjugated vaccine against encapsulated Haemophilus influenzae type b (Hib) has led to a dramatic reduction of invasive Hib disease. However, an increasing incidence of invasive disease by H. influenzae non-type b has recently been reported. Non-type b strains have been suggested to be opportunists in an invasive context, but information on clinical consequences and related medical conditions is scarce. In this retrospective study, all H. influenzae isolates (n = 410) from blood and cerebrospinal fluid in three metropolitan Swedish regions between 1997 and 2009 from a population of approximately 3 million individuals were identified. All available isolates were serotyped by PCR (n = 250). We observed a statistically significant increase in the incidence of invasive H. influenzae disease, ascribed to non-typeable H. influenzae (NTHi) and encapsulated strains type f (Hif) in mainly individuals >60 years of age. The medical reports from a subset of 136 cases of invasive Haemophilus disease revealed that 48% of invasive NTHi cases and 59% of invasive Hif cases, respectively, met the criteria of severe sepsis or septic shock according to the ACCP/SCCM classification of sepsis grading. One-fifth of invasive NTHi cases and more than one-third of invasive Hif cases were admitted to intensive care units. Only 37% of patients with invasive non-type b disease had evidence of immunocompromise, of which conditions related to impaired humoral immunity was the most common. The clinical burden of invasive non-type b H. influenzae disease, measured as days of hospitalization/100 000 individuals at risk and year, increased significantly throughout the study period.

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.

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.

Virulence characteristics of Escherichia coli strains causing acute cystitis in young adults in Iran.

BACKGROUND: Escherichia coli strains that cause cystitis posses virulence properties that facilitate their colonisation and persistence in the bladder. In Iran, despite the high number of the urinary tract infections, very few studies has been done to determine the role of these virulence properties in the pathogenesis of E. coli cyctitis. PATIENTS AND METHODS: Eighty-seven strains of E. coli, isolated from young adults with cystitis in Shiraz, Iran, were examined for the expression of type 1 and P-fimbriae, mannose resistant haemagglutination, haemolysin production, aerobactin-mediated iron uptake, O:K serotypes, biochemical phenotypes (BPTs) and their antibiotic susceptibility patterns. RESULTS: Seventy-six percent of the strains expressed multiple virulence properties. There was a significant correlation between the presence of aerobactin and the expression of type 1 fimbriae. All P-fimbriated strains produced aerobactin with 50% of them also coexpressing haemolysin. Of the 29 different O:K serotypes identified, 42% belonged to serotypes not commonly found among European serotypes associated with UTI. Strains of O groups 4 and 6 expressed more virulence factors than the others. A high resistance against ampicillin, trimethoprim and cotrimoxasol was observed among the isolates with 53% of the isolates showing multiresistance to these three antibiotics. Certain BPTs were also found among O:K serotypes with some containing strains of the same virulence profile. CONCLUSION: We conclude that certain colonal groups of E. coli are commonly associated with cystitis in young adults in Iran with strains possessing a combination of aerobactin and type 1 fimbriae being the dominant ones and belonging to serotypes not commonly found in Europe. We also conclude that the multiple antibiotic resistant E. coli strains causing cyctitis are highly prevalent in this part of the country.

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.

Perspectives on hepatitis B infections and the efficacy of vaccination (hepatitis B and pneumococci) in dialysis patients.

Hepatitis B is a well known problem in dialysis units. We therefore examined the historical frequency of hepatitis B carriers in our unit, our vaccination program to hepatitis B virus (HBV), the response to hepatitis B vaccine, the IgG subclass response of anti-HBs and the response and IgG subclass response to pneumococcal vaccination (another vaccine) in dialysis patients. From 1970 and onwards 23 HBV carriers were found, but no new cases of hepatitis B occurred during the study period, i.e. from 1980 and onwards. Only one of the carriers was alive by the end of 2001. In four patients liver disease (in one of them liver cirrhosis) may have been a concomitant cause of death. The antibody response to hepatitis B vaccine was significantly lower in patients than in staff. In four patients a fourth injection was cancelled due to transplantation and bad health, while such data were lacking in 8 cases. In anti-HBs positive patients and controls a significant difference in the response of healthy adults was observed in anti-HBs IgG1 (p < 0.001) vs all other IgG subclasses. Dialysis patients had low levels, or negative findings, in all cases, with IgG1 as the highest proportion found (3/11 patients). An antibody response to pneumococcal vaccination was registered in 25 out of 29 dialysis patients (in all 86%). The IgG-subclass vaccination response to pneumococci in 28 dialysis patients was mainly IgG2 and IgG1 but also occurred in IgG3 and IgG4. Prevaccination antibody levels of the controls were higher in IgG1 and IgG2 (p < 0.01) (n = 21) than in dialysis patients (n = 28). Hepatitis B is nowadays a rare, but still dangerous disease in nephrology units. Dialysis patients have a reduced response to hepatitis B vaccine and vaccination schedules should be started early as some patients otherwise may not receive a fourth injection. The adequate antibody response to pneumococcal vaccination mainly due to IgG2 and IgG1 antibodies indicates that the antigen involved is important in vaccination responses in dialysis patients.

Outbreak of Campylobacter infection in a subartic community.

A presumably waterborne outbreak of Campylobacter jejuni/coli infection in a subarctic community is described. Drinking water supplied to residents was delivered unchlorinated during a 4-week period. No Campylobacter sp. was recovered from the water supply. Three hundred thirty individuals (15% of the 2,200 exposed) became ill. Diarrhoea, abdominal pain, fever, nausea and joint pain occurred in 81%, 30%, 29%, 43% and 21%, respectively. Nine percent reported swelling of joints, and two cases of reactive arthritis occurred. A Campylobacter sp. was isolated from 9 of 33 individuals who became ill and from 1 of 33 healthy controls. All culture-positive individuals, 46% of culture-negative ill persons and 27% of healthy controls were seropositive. All strains recovered had an identical DNA profile.

Antibodies, directed towards Campylobacter jejuni antigens, in sera from poultry abattoir workers.

Occupational exposure of susceptible humans to Campylobacter jejuni appears to result in resistance to disease. This is believed to be due to acquired protective immunity. To support this hypothesis the levels of C. jejuni-specific IgG and IgM antibodies were determined in sera from poultry abattoir workers. Such individuals are persistently exposed to C. jejuni, but apparently rarely acquire campylobacteriosis. Sera from 43 short-term workers (employed < or = 1 month), 78 long-term workers and 40 blood donors were investigated by ELISA. In 51 individuals a second serum sample, taken at least 1 month after the first, was also investigated. Eight workers had C. jejuni-positive faecal cultures and only one, a short-term worker, had symptoms of campylobacteriosis. There were significantly higher levels of specific IgG antibodies in long-term workers than in either of the other groups. There was no significant difference detectable in specific IgM antibody levels between any of the groups. The results provide supporting evidence that long-term exposure to C. jejuni induces circulating antibodies which reflect apparent reduced susceptibility to disease. Western blotting showed flagellin and polypeptides of 45, 40, 32 and 30 kD bound antibodies significantly more frequently by sera from long-term workers than short-term workers and blood donors. The most commonly detected antigens were the 40-kD (80%) and flagellin (55%). The results indicate that specific serum IgG responses induced by endemic exposure to C. jejuni might be directed towards a small number of protein antigens with apparently conserved epitopes.

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.

Rapid emergence of high-level resistance to quinolones in Campylobacter jejuni associated with mutational changes in gyrA and parC.

Quinolone resistance in clinical isolates of Campylobacter jejuni in Sweden increased more than 20-fold at the beginning of the 1990s. Resistance to 125 microgram of ciprofloxacin per ml in clinical isolates was associated with chromosomal mutations in C. jejuni leading to a Thr-86-Ile substitution in the gyrA product and a Arg-139-Gln substitution in the parC product.

Occurrence and susceptibility to antibiotics of Shigella species in stools of hospitalized children with bloody diarrhea in Pakistan.

The aim of the present investigation was to study the frequency of Shigella spp. in patients with bloody diarrhea in Pakistan and the susceptibility of isolated Shigella to three antibiotics: ampicillin, cotrimoxazole and nalidixic acid. In addition, the frequency of Campylobacter and Salmonella was also determined. Stool samples (n = 152) were collected from 152 diarrheic children less than six years of age passing blood and mucus in their stools who were admitted to Paediatric Department of Mayo Hospital in Lahore, Pakistan from June to September 1990. The samples were cultivated on standard media for Shigella, Campylobacter, and Salmonella. Susceptibility of Shigella isolates was tested by disk diffusion method. The frequency of isolation was 19.1% for Shigella spp., 7.9% for Campylobacter, and 4.6% for Salmonella. Shigella flexneri (7.9%) was the most frequently isolated species, followed by S. dysenteriae (6.6%), S. boydii, (3.3%) and S. sonnei (1.3%). All Shigella isolates were susceptible to nalidixic acid (100%), while only a few were susceptible to cotrimoxazole (7.0%) and ampicillin (3.5%). In Pakistan, self-medication and purchases of drugs without a prescription are commonly practiced. Thus, there is a greater possibility of development of resistant strains due to over use of antibiotics.

Aetiology of acute epiglottitis in adults.

In order to determine the aetiology of acute epiglottitis in adults, blood cultures, paired sera and a urine sample were obtained from 54 patients with fever and epiglottitis visualized by indirect laryngoscopy or by direct fibreoptic nasolaryngoscopy. Antibodies were determined against the capsular polysaccharide of Haemophilus influenzae type b (Hib), 3 pneumococcal antigens (a mixture of 23 capsular polysaccharides, C-polysaccharide and pneumolysin) and antistreptolysin O. Acute sera were examined by the polymerase chain reaction (PCR) for DNA of Hib and pneumococci. The urine samples were examined for Hib capsular antigen. Blood cultures were positive in 15 patients. In another 16, serology and/or PCR verified the aetiology. Hib was the cause in 14, pneumococci in 12 and group A streptococci in 5 patients. The aetiology remained unknown in 23/54 patients (43%). In conclusion, the addition of serology and PCR to blood cultures doubled the possibilities of verifying the aetiology of acute epiglottitis in adults.

Bile duct bacterial isolates in primary sclerosing cholangitis: a study of explanted livers.

BACKGROUND/AIMS: The pathogenesis of the inflammatory lesion in primary sclerosing cholangitis is unknown. The clinical picture is characterized by i.a. episodes of fever, the cause of which also remains speculative. Previous studies of bacterial isolates in the liver or bile ducts in primary sclerosing cholangitis have had the shortcoming of possible contamination associated with the sampling. The aim of this study was to investigate whether bile and bile duct tissue, obtained under sterile conditions in connection with liver transplantation, contain bacteria. METHODS: We studied bile from bile duct walls and bile collected from the explanted livers of 36 patients with primary sclerosing cholangitis and 14 patients with primary biliary cirrhosis. RESULTS: Positive cultures were obtained from 21 of 36 primary sclerosing cholangitis patients, but from none of the primary biliary cirrhosis patients. The number of bacterial strains was inversely related to the time after the last endoscopic retrograde cholangiography. Treatment with antibiotics or intraductal stent, or the occurrence of fever before liver transplantation did not seem to influence the culture results, whereas antibiotic treatment in connection with endoscopic retrograde cholangiography may possibly have reduced the number of isolates in the cultures. Alpha-haemolytic Streptococci were retrieved as late as 4 years after the last endoscopic retrograde cholangiography. Retrospective analysis of liver laboratory tests after endoscopic retrograde cholangiography did not indicate a deleterious effect of the investigation. CONCLUSIONS: The data suggest that antibiotics should be given routinely in connection with endoscopic retrograde cholangiography. They also raise the question of a possible role of alpha-haemolytic Streptococci in the progression of primary sclerosing cholangitis.

Norfloxacin resistance in Campylobacter jejuni and Campylobacter coli isolates from Swedish patients.

This study focused on the frequency of Campylobacter jejuni and Campylobacter coli strains resistant to norfloxacin. Included were 1659 consecutive stool specimens isolated between 1992 and 1995, from as many Swedish patients with diarrhoea. The patients were divided with regard to place of infection and age. All strains were tested for susceptibility to norfloxacin by means of disc diffusion test on blood-agar plates. Norfloxacin-resistant strains (n = 310) were furthermore tested for resistance to doxycycline and erythromycin. The Etest was used for determination of MIC values of doxycyclin, erythromycin and norfloxacin of 81 of the strains. C. jejuni and C. coli isolations resistant to norfloxacin were significantly more frequent among patients infected abroad, especially in Spain and Thailand, compared with those infected in Sweden, adults more often than children. The number of resistant strains showed a yearly increase, and the difference between children and adults was equalized in 1995. The MIC50 and MIC90 values for doxycycline and erythromycin have increased markedly through the 4 years studied. This study shows that norfloxacin, because of increased resistance, may have limited utility for treatment of gastrointestinal infections caused by C. jejuni and C. coli.

Oral administration of antibodies as prophylaxis and therapy in Campylobacter jejuni-infected chickens.

Passive immunity against gastrointestinal infections has recently been successfully applied as prophylaxis and therapy in patients in a variety of virally and bacterially induced infections. Campylobacter jejuni is frequently associated with acute diarrhoea in humans, and several species of animals have been shown to transmit the disease, although birds have been implicated as the main source of infection. We used bovine and chicken immunoglobulin preparations from the milk and eggs, respectively, of immunized animals for prophylactic and therapeutic treatment of chickens infected with C. jejuni. A marked prophylactic effect (a >99% decrease in the number of bacteria) was noted using either antibody preparation, whereas the therapeutic efficacy, i.e. when antibodies were given after the infection was established, was distinctly lower (80-95%) as judged by faecal bacterial counts. These observations may serve as a starting point for experiments aimed at elimination of the infection in an industrial or farm setting. It may also encourage future attempts to treat, prophylactically or therapeutically, patients with Campylobacter-induced diarrhoea.

The serotype distribution of Campylobacter jejuni and C. coli isolated from patients with diarrhoea and controls at Tikur Anbassa Hospital, Addis Ababa, Ethiopia.

Sixty-eight isolates of Campylobacter jejuni and C. coli isolated from patients with diarrhoea (n = 630) and controls (n = 220) at Tikur Anbassa Hospital, Addis Ababa, Ethiopia were serotyped on the basis of the heat-labile (HL) and the heat-stable (HS) antigens, by using 16 and 34 antisera, respectively, for the two methods. With the antisera against heat labile antigens, 89.3% of the C. jejuni and 75% of the C. coli were typable. The HL serotypes 1, 2, 3, 4, 5, 6 and 7 were the most common among the C. jejuni while HL serotypes 1 and 2 were dominant among the C. coli isolates. These serotypes accounted for 63.2% of all isolates. For the heat-stable antigens, 60% of the C. jejuni and 83.3% of the C. coli isolates were typable. The HS serotypes 1, 3, 8, 26 and 34 were most common among the C. jejuni, while serotypes 3 and 8 were dominant among C. coli isolates. This study shows that the most common HL and HS antigens among campylobacter isolates from Ethiopia correspond to the most frequent antigenic types from other parts of the world. A limited number of antisera were sufficient to identify the majority of the isolates.

DNA fingerprinting and serotyping of Campylobacter jejuni isolates from epidemic outbreaks.

The aim of the present investigation was to compare DNA fingerprinting and serotyping (heat-stabile and heat-labile antigens) of isolates from epidemic outbreaks as well as of solitary isolates. Campylobacter jejuni isolates from two epidemic outbreaks in Sweden, one milkborne (35 isolates) and one waterborne (17 isolates), and one waterborne outbreak in Norway (11 isolates), as well as 30 solitary isolates from Swedish patients with gastroenteritis, were analyzed. A total of 93 isolates were analyzed. In the waterborne outbreak in Norway, only one serotype with one DNA pattern was found. In the milkborne outbreak in Sweden, two serotypes (HS2:HL4 and HSNT:HL4) with two different DNA patterns were found. The isolates from the waterborne outbreak in Sweden were different serotypes. For two isolates of the same serotype, different DNA patterns were seen. This was also recorded for isolates from solitary cases. It was concluded that serotyping is a useful tool in most epidemiological situations but sometimes lacks sufficient discriminatory power. DNA fingerprinting can add valuable epidemiological information to that supplied by serotyping and can in some situations provide sufficient epidemiological information when used alone.

In vitro studies of Campylobacter jejuni/coli strains from hens and humans regarding adherence, invasiveness, and toxigenicity.

Campylobacter jejuni/coli strains from hens and humans were compared for their ability to adhere to and invade HEp-2-cells and for toxigenicity to CHO-cells. In both hen and human strains, invasiveness was higher among non-toxigenic strains than among toxigenic ones. The frequency of adherence, invasiveness, and toxigenicity was the same in hen and human strains.

Campylobacter jejuni/coli and enterotoxigenic Escherichia coli (ETEC) in faeces from children and adults in Tanzania.

The occurrence of Campylobacter and enterotoxigenic E. coli (ETEC) was studied in faecal samples from Tanzanian children (< 5 years of age), adolescents and adults (only Campylobacter) with and without diarrhoea. The Campylobacter strains isolated were tested for subspecies, enterotoxigenicity and serotype. Out of 394 children with diarrhoea 18% were infected with Campylobacter and 20% with ETEC. In 278 samples tested for Campylobacter and 136 tested for ETEC from asymptomatic children the corresponding numbers were 12 and 5%, respectively. In children < 18 months with diarrhoea Campylobacter was noted in 22% and ETEC in 18%, whereas the figures were 11 and 4% respectively in asymptomatic children. In the age group 18 months to 5 years Campylobacter was demonstrated in 2% of the children with diarrhoea and 27% had ETEC, while the figures were 15 and 8% for asymptomatic children. Among adults the prevalence of Campylobacter-positive samples was 1% both for symptomatic and asymptomatic individuals. There were no seasonal differences in the prevalences of both Campylobacter and ETEC either in the symptomatic or the asymptomatic group. Campylobacter jejuni was the dominating Campylobacter species among both symptomatic and asymptomatic individuals. C. jejuni strains from patients with diarrhoea were significantly more often enterotoxigenic than were C. coli strains. The serotype pattern regarding Campylobacter was in general similar for symptomatic and asymptomatic individuals. We conclude that Campylobacter and ETEC are common causes of bacterial diarrhoea in Tanzanian children, and that Campylobacter infections are more important in children younger than 18 months, than in older ones.