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Biomedical subjects

M T Cafferkey

Publications and source records attributed to M T Cafferkey.

At least 19 recordsLinked to original sources

Screening for Chlamydia trachomatis in asymptomatic women attending outpatient clinics in a large maternity hospital in Dublin, Ireland.

BACKGROUND: Chlamydia trachomatis can cause a sexually transmitted infection, which, untreated, may result in considerable morbidity. METHODS: A prevalence study was conducted for C trachomatis using nucleic acid amplification technology in asymptomatic women, and certain risk factors that may be used to direct future screening strategies were assessed. RESULTS: The study population comprised 945 asymptomatic women, of whom 783 were attending antenatal clinics, 91 were attending infertility clinics and 71 were attending family planning clinics. An overall C trachomatis prevalence of 3.7% (35/945) was found, with the highest prevalence of 11.2% (22/196) in Irish single women aged <25 years. Logistic regression analysis showed that single status and age <25 years were independent, statistically significant predictors of C trachomatis infection. CONCLUSION: These results support routine screening of asymptomatic women who are sexually active and aged <25 years. An opportunist active screening of all sexually active women independent of age should be additionally considered if resources permit.

Adult↗

Susceptibility to infectious rash illness in pregnant women from diverse geographical regions.

Varicella-zoster (VZV), rubella (RV) and parvovirus B19 (B19V) infections are important causes of rash illness in pregnancy, due to their potential adverse impact on both mother and fetus. We determined susceptibility to these infections in pregnant women attending our hospital in 2002. Age and nationality were recorded. Sera were tested for VZV, RV, and B19V antibody by enzyme immunoassay. Of 7,980 women screened for VZV IgG, 11.3% were seronegative and therefore susceptible to infection. Across different worldwide regions, 6.9% of Irish and other Western European women were susceptible to VZV, compared to 19.7% of other women tested (p < 0.001), most of whom were from Central and Eastern Europe, sub-Saharan Africa and Asia. Of 7,872 women screened for RV IgG, 2.3% were seronegative. Few Irish (0.6%) or other Western European women (0.7%) were rubella non-immune, but 5.5% of women from other regions tested were susceptible to rubella (p < 0.001). A random subset of 1,048 women were tested for B19V IgG. About 38% were susceptible, varying from 22% to 63% across the different regions studied. There are important differences in immunity to these infections and so of potential risk of an adverse outcome in indigenous and immigrant pregnant women in Ireland.

Adult↗

Irish strains of Neisseria meningitidis: characterisation using multilocus sequence typing.

A total of 56 Neisseria meningitidis strains are analysed using multilocus sequence typing (MLST). Twenty-nine distinct sequence types (STs) were identified, eight of which were new. Four known hypervirulent clones--ST-11 (electrophoretic type [ET]-37) complex, ST-44 complex (lineage 3), ST-32 (ET-5) complex and ST-8 complex (cluster A4)--were identified by MLST in 35 disease-associated and four carrier strains. Two other clones (ST-22 complex and ST-269 complex) were identified in nine disease-associated and one carrier strain. The remaining strains were heterogeneous. Additional sequencing within the FumC gene further distinguished the ET-15 clone within the ST-11 (ET-37) clonal complex. This resolution of isolates into genetic clones by MLST enhances the more traditional techniques of serotyping and serosubtyping. The data obtained established that hyperendemic meningococcal disease in Ireland could be attributed to strains belonging to four major hypervirulent clones, all of which account for elevated levels of disease worldwide. The extra information provided by MLST will be used to study the population structure and epidemiology of N. meningitidis and will allow a comparison of Irish strains with those circulating globally.

Bacterial Typing Techniques↗

Antenatal hepatitis B screening - is there a need for a national policy?

Routine antenatal testing for hepatitis B carriage with maternal consent was introduced at the Rotunda in January 1998. The uptake of testing has been excellent; 99.98% of women presenting for antenatal care accepted hepatitis B (HBV) screening in the 30-months from January 1998 through June 2000. The prevalence of HBV carriage was 0.35% (58 pregnancies of 16,222 tested) increasing from 0.25% in 1998 (16 of 6227) to 0.45% in the first six months of 2000 (16 of 3484). Fifty-five women had 58 pregnancies (three women had two pregnancies). Two of these were e-antigen positive. HBV carrier status was previously unknown in 48 (87%). Two additional women had acute HBV infection in pregnancy. Forty-five infants have been born to mothers included in this screening programme. Audit of infant outcome reveals excellent compliance with immunisation and follow-up: 29 (64%) have completed the 3 dose HBV vaccination schedule to date. Thirteen infants (31%) are still attending; three are lost to follow-up including one whose family has emigrated. Routine antenatal screening for hepatitis B carriage is cost-effective and should be considered a standard of care in maternity practice.

Carrier State↗

Bacteriology of normal and diseased tonsils assessed by fine-needle aspiration: Haemophilus influenzae and the pathogenesis of recurrent acute tonsillitis.

The pathogenesis of recurrent tonsillitis is largely unknown. Selection of appropriate antibiotic therapy for patients with recurrent tonsillitis is difficult because of the limitations of traditional methods of sampling tonsillar microflora and the increasing incidence of beta-lactamase producing bacteria in the tonsil. In addition, little attention has been paid to the bacteriology of normal tonsils. The tonsil core bacteria was assessed in 124 patients with recurrent acute tonsillitis. Fifty-five of these patients were randomly selected for fine-needle aspiration which revealed a similar profile of bacteria in 85%. Fine-needle aspiration of 10 normal tonsils found few pathogens; the predominant organisms being normal flora. No Haemophilus influenzae were detected in this control group. This study demonstrates the accuracy of fine-needle aspiration in identifying tonsil core bacteriology and its suitability in the clinical setting. It reports on the flora of normal healthy tonsils and it highlights the association between H. influenzae and recurrent acute tonsillitis.

Acute Disease↗

Meningococcal disease in the Republic of Ireland: 1995.

Two hundred and nine culture confirmed cases of meningococcal disease were reported in the Republic of Ireland in 1995, using a new laboratory based surveillance system. The reported rate of 5.9/100000 population is one of the highest in western Europe, but the rate differed widely between regions. Fifty-three per cent of cases were female. Half of the cases occurred in four months (January, February, March, and December). Nineteen cases (9%) died. The highest age specific incidence was in infancy (under 1 year). Infections with serogroup B accounted for 105 cases (54%) and serogroup C 87 cases (45%). We estimate that up to 30% of cases of meningococcal disease may be preventable when conjugate meningococcal group C vaccines become available, but cost benefit analyses will be required to determine how they should be employed.

Adolescent↗

The in-vitro susceptibilities of vaginal lactobacilli to four broad-spectrum antibiotics, as determined by the agar dilution and E test methods.

The minimum inhibitory concentrations (MICs) of cefaclor, co-amoxiclav, clarithromycin and ciprofloxacin for 59 strains of vaginal lactobacilli were determined by both the reference agar dilution and E test methods. With the exception of clarithromycin, there was poor correlation between the results obtained by the two techniques. This was most apparent for the beta-lactams studied, the MICs of cefaclor as determined by the E test being particularly difficult to define. The stability of antimicrobial gradients in the E test may cause problems when testing slow-growing bacteria and/or organisms which grow only under anaerobic conditions. Accordingly, only those MICs determined by the agar dilution method are reported. The percentages of susceptible isolates were as follows: clarithromycin, 100; co-amoxiclav, 100; cefaclor, 20; and ciprofloxacin, 4. The administration of antimicrobials, such as ciprofloxacin and cefaclor, which have poor activities in vitro against lactobacilli, may therefore be advantageous to the host because it allows the protective effects of the normal vaginal flora to be preserved.

Agar↗

Chemoprophylaxis of invasive pulmonary aspergillosis.

Invasive aspergillosis in now the second most common mycosis encountered in patients with cancer, particularly those with haematological malignancies. The present review discusses strategies for the chemoprophylaxis of invasive pulmonary aspergillosis. Recommendations for chemoprophylaxis are currently based on the particular fungal pathogens seen in individual centres and the resources available. In many units, only BMT recipients are nursed in protected environments and the majority of patients at risk of invasive mycosis, i.e. patients undergoing remission induction or consolidation therapy, are nursed on open wards. The studies so far reported have included relatively small numbers of patients and provide insufficient data for definitive recommendations. The measures used at present should be considered as ad hoc approaches for use in units in which spore-free air for profoundly neutropenic patients is lacking. Nebulized amphotericin B allows deposition of a chemical barrier throughout the airways. Intravenous low dose amphotericin B would be protective when invasion occurs and is clearly the chemoprophylaxis of choice in patients with an established diagnosis of previous invasive aspergillosis at any site. The role of surgery in removing a focus of infection before further chemotherapy, should not be overlooked. The potential role of cytokines in accelerating host defence recovery may in future also prove to be important in controlling invasive fungal infection.

Animals↗

Serotype F double- and triple-converting phage insertionally inactivate the Staphylococcus aureus beta-toxin determinant by a common molecular mechanism.

The precise molecular mechanism of Staphylococcus aureus beta-toxin inactivation by the serotype F triple-converting phage phi 42, phi A1 and phi A3 was investigated. Sequence analysis of the phi 42 (attP) and Staphylococcus aureus (attB) attachment sites and the left (attL) and right (attR) chromosomal/bacteriophage DNA junctions of individual lysogens, each harbouring a triple-converting phage, revealed the presence of a common 14-bp core sequence in all four sites. These findings indicate that the genomes of the triple-converting phage integrate into the 5'-end of the beta-toxin gene (hlb) by a site- and orientation-specific mechanism identical to that previously described for the serotype F double-converting phage phi 13.

Attachment Sites, Microbiological↗

Yersinia frederiksenii infection and colonization in hospital staff.

A diagnosis of gastrointestinal infection with Yersinia frederiksenii was made in a 24-year-old female hospital doctor, resident in hospital. An additional three of nine medical residents screened were found to be faecal carriers of Y. frederiksenii. The latter three residents denied any gastrointestinal symptoms. Screening of 25 resident nurses and 25 in-patients for carriage of Y. frederiksenii was negative. Initial investigation revealed that the medical residents frequently drank unpasteurized milk, which was supplied on the understanding that it would be used for cooking only. Counts of > 10(8) cfu l-1 were obtained from unpasteurized milk samples, including 24 species of Gram-negative bacilli. Yersinia spp. were not isolated. Residents also drank water from the cold taps in the bedrooms; this water was supplied by a holding tank on the hospital roof. Subsequent investigations revealed that three of the 21 holding tanks supplying stored water to the hospital were not covered. Y. enterocolitica was isolated from the uncovered water tank supplying the medical residence.

Adult↗

Bacteriology of tonsil and adenoid and sampling techniques of adenoidal bacteriology.

The value of pernasal swabs and direct adenoid swabs in chronic adenoid and adenotonsillar disease was assessed in 175 patients. Prior to adenoidectomy (53 patients) or adenotonsillectomy (122 patients), pernasal and direct adenoid swabs were taken. Adenoid currettings and tonsil tissue were cultured. Haemophilus influenzae was the bacterium most frequently isolated from adenoid currettings and from the centre (core) of the resected tonsil. There was a close relationship between the bacteriology of the pernasal swab and the adenoid tissue and tonsil core in 72 and 71% of patients, respectively. There was an identical profile of pathogens in 52 and 49%, respectively. We suggest that in children with adenoiditis or adenotonsillitis and hypertrophy of the adenoid, a pernasal swab should be used in preference to a throat swab in selecting appropriate antimicrobial therapy. Penicillin and ampicillin are not appropriate blind therapy in chronic adenoid and adenotonsillar infections because of the prevalence of beta-lactamase-producing aerobes (40%) in adenoid and tonsil core in these conditions.

Adenoidectomy↗

Effect of pre-operative antibiotic treatment on the bacterial content of the tonsil.

The impact of 7 days pre-tonsillectomy antibiotics on the aerobic bacterial content of the tonsil was studied in 70 consecutive patients. One group received no antibiotic, one group received pre-operative amoxycillin and the final group, pre-operative cefaclor. The qualitative bacteriology was similar in the three groups Haemophilus influenzae was the predominant isolate present in the centre ('core') of the resected tonsil. Similar numbers of beta-lactamase producers including H. influenzae and Straphylococcus aureus were found in all three groups. Quantitative bacteriology of the tonsil core demonstrated that there was a significant reduction in core tonsil pathogens associated with antibiotic therapy. The most statistically significant difference was between the untreated control group and the cefaclor treated group. We conclude that in patients with established recurrent acute tonsillitis, oral antibiotics penetrate the diseased tonsil and influence the predominant core aerobic microflora.

Adolescent↗

Post-tonsillectomy bacteraemia.

Post-tonsillectomy bacteraemia is a well recognized aetiological factor in streptococcal endocarditis. Prophylactic penicillin has been recommended to reduce its incidence in susceptible patients undergoing tonsillectomy. Recent studies have shown a change in the microflora and an increase in the number of penicillin resistant organisms in the tonsils of patients undergoing tonsillectomy. The aim of this study has been to assess the incidence of post-tonsillectomy bacteraemia, identify the organisms associated with it and review the suitability of penicillin in prophylactic regimens. Of the 32 patients included in the study, 11 (34.4%) had positive post-tonsillectomy blood cultures. We were surprised at this low incidence of bacteraemia and have postulated a possible reason. Haemophilus influenzae was isolated from 4 (36.4%) of the positive cultures and Streptococcus viridans in only 1 (9%). Rather than using penicillin for prophylaxis a beta-lactamase stable antibiotic would be more appropriate.

Bacteremia↗

Fine-needle aspiration in recurrent tonsillitis.

The incidence of tonsillitis that is unresponsive to penicillin therapy is leading to concern. This phenomenon has been linked to a change in the core tonsil bacteria, in particular beta-lactamase production. To date, the only way to identify the presence of these resistant microbes is at tonsillectomy. In this prospective study, we performed fine-needle tonsil aspiration in 34 patients (mean age, 7.6 years) before tonsillectomy. The bacteriologic nature of the aspirate was compared with that obtained from culturing the tonsillar surface (in situ) and core of the resected tonsils. The bacteriologic findings of the aspirate corresponded closely with those of the tonsil core (qualitative and quantitative comparison), while the superficial swab was of limited value in predicting the core bacteria. Based on this study, tonsil fine-needle aspiration may have a place in the treatment of recurrent tonsillitis.

Adolescent↗

Differences in tonsil core bacteriology in adults and children: a prospective study of 262 patients.

The tonsillar microflora of 262 patients with recurrent acute tonsillitis studied in 1989-1990 is presented. The patient population was divided into three age groups to determine any age-related features. One-hundred and forty-nine patients (57%) were in the 2-7-year-old group, 72 (28%) the 8-14-year-old age group, and the remaining 41 (15%) were over 15 years of age. H. influenzae was the single most common bacterium isolated from the centre of the tonsil (referred to as 'tonsil core'), and this was more prevalent in the 2-7-year-old age group. Staph aureus was the next most commonly isolated bacterium and was most frequently seen in the 8-14-year-old age group (29%). Anaerobic bacteriology was performed in 120 patients. Strict anaerobic species were isolated in significant numbers from the tonsil core in 5% but were present in the superficial culture in all. Anaerobes were present in moderate to heavy numbers in 32% of superficial swabs overall and this was more frequently seen in the older age groups. Mixed pathogens were found throughout all age groups and were most prevalent in the 8-14-year-old age group at 46%. The commonest mixture was H. influenzae and Staph aureus. Normal flora only was commonly found in the superficial swab and rarely in the tonsil core. The number of specimens containing a beta-lactamase producer was assessed for each group; this was similar in all of the groups ranging from 43% in the 2-7-year-old group and 53% in the 8-14-year-old group to 39% in the greater than 15-year-old group.

Adolescent↗