Increase of ß-lactam-resistant invasive Haemophilus influenzae in Sweden, 1997 to 2010.

The proportions of Haemophilus influenzae resistant to ampicillin and other ß-lactam antibiotics have been low in Sweden compared to other countries in the Western world. However, a near-doubled proportion of nasopharyngeal Swedish H. influenzae isolates with resistance to ß-lactams has been observed in the last decade. In the present study, the epidemiology and mechanisms of antimicrobial resistance of H. influenzae isolates from blood and cerebrospinal fluid in southern Sweden from 1997 to 2010 (n = 465) were studied. Antimicrobial susceptibility testing was performed using disk diffusion, and isolates with resistance to any tested ß-lactam were further analyzed in detail. We identified a significantly increased (P = 0.03) proportion of ß-lactam-resistant invasive H. influenzae during the study period, which was mainly attributed to a significant recent increase of ß-lactamase-negative ß-lactam-resistant isolates (P = 0.04). Furthermore, invasive ß-lactamase-negative ß-lactam-resistant H. influenzae isolates from 2007 and onwards were found in higher proportions than the corresponding proportions of nasopharyngeal isolates in a national survey. Multiple-locus sequence typing (MLST) of this group of isolates did not completely separate isolates with different resistance phenotypes. However, one cluster of ß-lactamase-negative ampicillin-resistant (BLNAR) isolates was identified, and it included isolates from all geographical areas. A truncated variant of a ß-lactamase gene with a promoter deletion, bla(TEM-1)-PΔ dominated among the ß-lactamase-positive H. influenzae isolates. Our results show that the proportions of ß-lactam-resistant invasive H. influenzae have increased in Sweden in the last decade.

The hygienic effectiveness of 2 different skin cleansing procedures.

PURPOSE: This study was designed to assess the ability of 2 skin cleaning procedures to remove transient microbial flora from the skin. DESIGN: The study is a direct comparison of 2 washing procedures: soap and water washing versus cleansing with a no-rinse cleanser. SETTING AND SUBJECTS: The trial was performed at the research facilities of the Department of Clinical Bacteriology at the University of Göteborg. Forty-five healthy adult volunteers were recruited to participate in the study. METHODS: A solution of test bacteria, either Escherichia coli or Staphylococcus aureus, was applied to both forearms of the test subject. After a 15-minute incubation period, one arm was cleaned using soap and water and the other arm was cleaned with no-rinse cleanser. Both the arms were dried with a disposable cloth. The amount of residual bacteria on the skin was assessed using contact agar plates. RESULTS: Both methods of cleaning resulted in 4-to 5-fold log reductions in bacterial count. The number of residual bacteria after both procedures ranged from 1 to 4 colony-forming units/cm after washing. The amount of residual bacteria was comparable for both washing procedures. CONCLUSIONS: Both washing procedures resulted in a low level of residual bacteria on the skin. No-rinse cleansers can be safely used as an alternative to soap and water washing of fragile skin.

Humoral immunity to tetanus, diphtheria and polio in adults after treatment for hematological malignancies.

INTRODUCTION: After chemotherapy, children with acute lymphocytic leukemia lose immunity and need revaccination against tetanus and diphtheria. However, little is known about immunity in adult patients after treatment for hematological malignancies. In this study, we assessed serology levels against polio, diphtheria and tetanus in adult patients after conventional treatment for leukemia and lymphoma. PATIENTS: One hundred and four patients, age 61 (19-86) years, were included at a median of 18 (4-77) months after chemotherapy for acute leukemia (n = 24) or lymphoma (n = 80). Pre-treatment sera were available in 73 cases for a pre-versus post treatment comparison. Healthy, age- and sex matched controls were available for 47 pts. METHODS: Tetanus antibodies were quantified using ELISA, and antibody levels ≥0.01 IU/mL were considered protective. Diphtheria antibodies were analyzed using neutralization test (n = 60) or by ELISA (n = 44). In both tests values ≥0.01 IU/mL were considered protective. Antibodies against poliovirus serotype 1 and 3 were assessed by a neutralizing test. A microneutralization titer of ≥2 was considered protective. RESULTS: Tetanus: There were significantly more non-immune patients after treatment (24%), compared to before (12%), p = 0.02. Post-treatment antibody levels were significantly lower than pre-treatment levels (p = 0.02). Diphtheria: There was a trend, p = 0.06, towards more non-immune patients after treatment (21%) compared to before (27%). Antibody levels post treatment were lower than pre treatment levels (p = 0.03) and lower than controls (p = 0.01). Polio: There was no significant difference in the number of non-immune patients before vs after chemotherapy for either PV1 or PV3. Protective immunity against serotype 1 and 3 was preserved in 90 and 97%, respectively. CONCLUSIONS: After standard chemotherapy for leukemia and lymphoma a significant proportion of patients had impaired humoral immunity to diphtheria and tetanus. However, polio immunity was well preserved.

Transmission dynamics study of tuberculosis isolates with whole genome sequencing in southern Sweden.

Epidemiological contact tracing complemented with genotyping of clinical Mycobacterium tuberculosis isolates is important for understanding disease transmission. In Sweden, tuberculosis (TB) is mostly reported in migrant and homeless where epidemiologic contact tracing could pose a problem. This study compared epidemiologic linking with genotyping in a low burden country. Mycobacterium tuberculosis isolates (n = 93) collected at Scania University Hospital in Southern Sweden were analysed with the standard genotyping method mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR) and the results were compared with whole genome sequencing (WGS). Using a maximum of twelve single nucleotide polymorphisms (SNPs) as the upper threshold of genomic relatedness noted among hosts, we identified 18 clusters with WGS comprising 52 patients with overall pairwise genetic maximum distances ranging from zero to nine SNPs. MIRU-VNTR and WGS clustered the same isolates, although the distribution differed depending on MIRU-VNTR limitations. Both genotyping techniques identified clusters where epidemiologic linking was insufficient, although WGS had higher correlation with epidemiologic data. To summarize, WGS provided better resolution of transmission than MIRU-VNTR in a setting with low TB incidence. WGS predicted epidemiologic links better which could consolidate and correct the epidemiologically linked cases, avoiding thus false clustering.

Species identification by genotyping and determination of antibiotic resistance in Campylobacter jejuni and Campylobacter coli from humans and chickens in Sweden.

Campylobacter is today the most common cause of human bacterial enteritis in Sweden, as well as in most other industrialized countries. Common sources of infection are undercooked chicken meat, unpasteurized milk and contaminated drinking water. One aim with our present study was to identify the species Campylobacter jejuni and Campylobacter coli strains from humans and chickens using a polymerase chain reaction/restriction enzyme analysis (PCR/REA) method, as well as traditional hippurate hydrolysis test. Another aim was to investigate the antibiotic resistance pattern of the human domestic C. jejuni/C. coli isolates from infected patients and isolates from healthy Swedish chicken, as well as isolates from humans infected abroad. If discrimination between C. jejuni and C. coli was based on testing for hippurate hydrolysis, 95% of the human domestic strains and 88% of the chicken strains were identified as C. jejuni. Based on genotyping by PCR/REA, 100% of the human domestic strains and 98% of the chicken strains were attributed to C. jejuni. The E-test and disc diffusion methods were used for phenotypic antibiotic resistance studies. The two methods gave similar results. Most Swedish C. jejuni/C. coli isolates both from humans and chickens were sensitive to doxycycline and erythromycin, which are antibiotics used to treat human infection. Only 7% of the human domestic strains and 2% of the chicken strains were resistant to the quinolones tested. As a comparison, more than 94% of strains isolated from travelers to Asia and southern Europe showed antibiotic resistance to one or more drugs.

Helicobacter pylori antibodies and iron deficiency in female adolescents.

OBJECTIVE: Iron deficiency (ID) is a common clinical problem worldwide, affecting primarily females. Helicobacter pylori (HP) infection has been shown to be associated with ID. The objective of this study was to define the prevalence of HP antibodies in female adolescents, and to find out if there was a correlation between HP infection and ID. The secondary aim was to study if regularly performed sporting activity, have any association to HP infection, in itself. DESIGN: A controlled clinical trial. SETTING: A senior high school in Gothenburg, Sweden. SUBJECTS: All female athletes at a senior high school for top-level athletes were offered to take part, and 56 athletes took part in the study. The control group consisted of a random sample of age-matched non-athlete students of which 71 entered the study. MAIN OUTCOME MEASURES: Iron deficiency (ID) and iron deficiency anaemia (IDA) were defined by the use of levels of haemoglobin, serum iron, total iron-binding capacity, transferrin saturation, and serum ferritin, as previously described. HP IgG-antibodies were detected by ELISA. RESULTS: 18 of 127 (14%) adolescent females had antibodies against HP. Only 3% had IDA, while 50% had ID. In total, 66% of the HP positive females had ID compared to 48% of the negative females (p = 0.203). No correlation between sporting activity and HP infection was found. Regarding ethnicity, 11/28 of subjects from medium-high risk areas were HP-positive, compared to 7/99 coming from low-risk areas (p<0.001). CONCLUSION: The main finding of this study is that the prevalence of HP IgG antibodies was 14% in adolescent females. We could not find any difference regarding frequency of ID and IDA, between HP positive and negative individuals. Ethnicity is of great importance for the risk of HP infection, while sporting activity itself seems to have no association to HP-infection.

Enterohemorrhagic Escherichia coli (EHEC).

Enterohaemorrhagic Escherichia coli has since the last 2 decades been known to cause severe and bloody diarrhoea as well as haemorrhagic colitis (HC) and haemorrhagic uraemic syndrome (HUS) especially among children. The importance of screening for EHEC among children and older patients with severe symptoms is apparent. Production of the verocytotoxins VT1 and VT2 are the main features of EHEC, and the VT types and mode of action during human infection is described. There are, however, other features adding to the pathogenicity. In this review we deal with the importance of properties such as fimbriae and adhesins as well as systems to meet the bacterial need for iron during infection. These factors are probably important for the establishment of EHEC in the gut and add to the bacterial virulence. It has now become evident that VT producing E. coli, irrespective of serogroup, might be human pathogens. We conclude that knowledge of the different possible virulence factors adds to the possibility of separating more virulent from less virulent isolates.

Genetic profiling of Campylobacter jejuni strains from humans infected in Sweden or in Thailand, and from healthy Swedish chickens, studied by pulsed-field gel electrophoresis (PFGE).

The major objective of the study was to explore the genomic diversity between Campylobacter jejuni (C.jejuni) from different sources as a tool for epidemiological considerations. Subtyping was performed using pulsed-field gel electrophoresis (PFGE) and the enzyme used for cleavage was SmaI. Isolates originated from humans infected in Sweden (n=49) and Thailand (n=32) and from healthy Swedish chickens (n=51). Eight PFGE groups were formed in a dendrogram and 48% of the isolates belonged to 1 of these groups. In 2 PFGE groups, strains from humans infected in both Sweden and Thailand were represented. Four of the PFGE groups comprised high frequencies of strains from domestic human infection, as well as from healthy chickens. The PFGE pattern was also compared with the antibiotic resistance pattern in all the above-mentioned isolates. In conclusion, C.jejuni was a diverse group based on PFGE genotyping; about 24% of the clones from Swedish patients and healthy Swedish chickens were similar; and there was no correlation between the antibiotic resistance pattern and the PFGE profiling among the studied strains. Our findings are also in accordance with our hypothesis that there may be similarities between Swedish and Thai strains, which might support a theory of globally occurring C.jejuni.

Genetic profiling of enterohemorrhagic Escherichia coli strains in relation to clonality and clinical signs of infection.

Sixty-seven human strains of enterohemorrhagic Escherichia coli (EHEC) (from patients with more or less severe symptoms) were serogrouped and arranged according to pulsed-field gel electrophoresis (PFGE) patterns. We used PCR to investigate the strains according to known or putative virulence factors, and associations with disease were studied. All EHEC strains with the same PFGE pattern belonged to the same serogroup. On the contrary, two serogroups (O157 and O8) included strains with different PFGE patterns. We found several different combinations of chromosomal and plasmid-borne determinants, encoding the putative virulence factors, among the strains. As judged from clinical symptoms, there was no marked difference in pathogenicity among the strains and their combinations of virulence traits. All strains of O157 had the genes coding for verocytotoxin (VT) 2, intimin (eaeA), E. coli hemolysin (E-hly), and secreted serine protease (espP). Among EHEC non-O157 strains, the genes coding for VT1 and VT2 were equally dispersed. EaeA positivity was just as common among VT1- as VT2-positive strains. Among the plasmid-borne determinants, E-hly and espP were the most common and E-hly might be a pathogenicity marker among EHEC non-O157 strains. The conclusion is that PFGE is a very useful tool in epidemiological studies. The EHEC plasmids are heterogeneous in their gene composition, with the four plasmid-borne determinants found in many combinations. There was no reliable correlation between chromosomal and plasmid-borne virulence factors and human disease.