The in-vitro activity of clarithromycin and other macrolides against the type strain of Chlamydia pneumoniae (TWAR)

The activity of oxytetracycline and seven macrolide antibiotics was investigated against a prototype strain of Chlamydia pneumoniae in cell culture. Following incubation, inoculated cell monolayers were fixed in methanol and stained with a genus specific immunofluorescent monoclonal antibody before examination for inhibition of inclusion formation. The most active agent was clarithromycin (MIC 0.007 mg/l), followed by erythromycin (0.06 mg/l). Other macrolides were less active; josamycin and roxithromycin (0.25 mg/l), midecamycin acetate and azithromycin (0.5 mg/l) and spiramycin (4.0 mg/l). The MIC of oxytetracycline was 0.25 mg/l. Clinical evaluation of clarithromycin for C. pneumoniae lower respiratory infection is indicated.

Non-gonococcal urethritis in men practising "safe" sex

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Toxic dilatation of the colon in shigellosis

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The in-vitro antibiotic susceptibility of Chlamydia pneumoniae

A cell culture technique was used to test the in-vitro susceptibility of the type strain of Chlamydia pneumoniae to 23 antibiotics including macrolides, tetracyclines and quinolones. The activity of the antibiotics tested was similar to previous findings with C. trachomatis. Clarythromycin had the lowest MIC overall (0.007 mg/l). Other macrolides were found to have similar MICs to erythromycin (0.06 mg/l). Both the macrolides and the tetracyclines were more active than the quinolones. It is proposed that the tetracyclines and erythromycin should be the drugs of choice for treating infections with C. pneumoniae; however several other antibiotics need to be evaluated.

Is a test of cure necessary following treatment for cervical infection with Chlamydia trachomatis?

Tests of cure (TOC) were performed on specimens from 106 women following treatment for chlamydial infection of the cervix. 91 women attended for the first TOC with enzyme immunoassay (EIA) within one week of finishing antibiotics. Three were EIA positive, 88 were EIA negative. These three women were subsequently EIA and culture negative although they received no further antibiotics. Ninety women returned for the second TOC with EIA and culture between seven and 27 days after completing treatment. All the results were negative. Routine TOC is unnecessary following appropriate antichlamydial therapy. If TOC is indicated antigen-detection methods should not be used immediately after finishing antibiotics as misleading positive results may be obtained. EIA or culture at one week or later after treatment is reliable.

A microbiologist's view of commissioning operating theatres

We report our experiences of microbiological testing of operating theatres over a 10-year period. Major faults within the theatres can be detected by microbiological monitoring of air flow direction and the bioload in theatre air. We advocate that there should be a close cooperation between the microbiologist and the hospital engineering department for effective monitoring of theatre commissioning and upgrading. Also we recommend that contract work should be closely supervised particularly with respect to theatre ventilation systems.

Comparison of an enzyme immunoassay (Ortho) with cell culture and immunofluorescence for the detection of genital chlamydial infection

An enzyme immunoassay (EIA) test (Ortho Diagnostic Systems Ltd) was evaluated against cell culture for the detection of chlamydial genital infection. Specimens were obtained from 409 patients (204 men and 205 women). Sensitivity, specificity, predictive value of a positive result (PVP) and predictive value of a negative result (PVN) for the new test compared to cell culture were respectively 73.1%, 93.8%, 63.3% and 96% for men and 80%, 95.6%, 71.4% and 97.2% for women. Discrepancies were further evaluated by repeating the EIA, and by direct immunofluorescence (IF) on the EIA transport buffer. The sensitivity, specificity, PVP and PVN of the EIA against the combination of cell culture and direct IF were respectively 76.7%, 96%, 76.7% and 96% for men, and unchanged for women. Overall agreement between the EIA and the combination of cell culture and direct IF was 93.4%. The EIA is rapid and simple to perform and does not require elaborate equipment.

Enzyme immunoassay compared with cell culture and immunofluorescence for detecting genital chlamydia

A novel enzyme immunoassay test (Pharmacia EIA) was evaluated against cell culture for the detection of chlamydial genital infection. Specimens were obtained from 525 patients (257 men and 268 women). Sensitivity, specificity, predictive value of positive (PVP) and predictive value of negative (PVN) for the new test were, respectively, 83.6, 98.5, 94.4 and 95.1% for men and 86, 97.2, 87.8 and 96.8% for women. Discrepancies were further evaluated by repeating the EIA, and by direct immunofluorescence on the EIA transport buffer. The sensitivity, specificity, PVP and PVN of the EIA against the combination of cell culture and direct immunofluorescence were, respectively 85.9, 100, 100, and 95.5% for men, and 90.5, 98.1, 92.3 and 97.7% for women. Overall agreement between the EIA and the combination of cell culture and direct immunofluorescence was 97%. The Pharmacia EIA is rapid and simple to perform and does not require elaborate equipment.

Comparative in vitro activity of lomefloxacin, a difluoro-quinolone

Lomefloxacin is a new difluoro-quinolone. In this study, we have determined the in vitro activity of lomefloxacin against a wide range of clinical bacterial isolates and compared it with that of other fluoro-quinolones and some unrelated antimicrobials. Lomefloxacin was very active against Enterobacteriaceae (MIC90, 0.5 micrograms/ml) with activity comparable to that of ofloxacin (MIC90, 0.25 micrograms/ml). Lomefloxacin was moderately active against isolates of Pseudomonas aeruginosa (MIC90, 4 micrograms/ml), and again the activity was comparable to ofloxacin (MIC90, 4 micrograms/ml) but was eightfold less than ciprofloxacin (MIC90, 0.5 micrograms/ml). Lomefloxacin was also active against isolates of Staphylococcus aureus (MIC90, 1 micrograms/ml), irrespective of methicillin susceptibility, and this activity was most comparable to ofloxacin (MIC90, 0.5 micrograms/ml) and ciprofloxacin (MIC90, 0.5 micrograms/ml). Lomefloxacin was fourfold less active than either ofloxacin or ciprofloxacin against isolates of Enterococcus faecalis (MIC90, 8 micrograms/ml) and Streptococcus pneumoniae (MIC90, 8 micrograms/ml). In common with ofloxacin and ciprofloxacin, lomefloxacin was very active against isolates of Neisseria spp. (MIC90, less than or equal to 0.06 micrograms/ml), Haemophilus spp. (MIC90, less than or equal to 0.06 micrograms/ml), Legionella spp. (MIC90, less than or equal to 0.06 micrograms/ml), Vibrio spp. (MIC90, less than or equal to 0.06 micrograms/ml), and Campylobacter jejuni (MIC90, 1 microgram/ml). Lomefloxacin showed poor activity against isolates of Bacteroides spp. (MIC90, 16 micrograms/ml) or Clostridium difficile MIC90, 32 micrograms/ml) and was only moderately active against isolates of Clostridium perfringens (MIC90, 2 micrograms/ml), Peptostreptococcus spp. (MIC90, 4 micrograms/ml), Chlamydia trachomatis (MIC90, 4 micrograms/ml), Mycoplasma hominis (MIC90, 2 micrograms/ml), and Urea-plasma urealyticum (MIC90, 8 micrograms/ml). Lomefloxacin was found to be bactericidal at concentrations generally close to the MIC with greater than 3 log10 reduction in viability of exponentially dividing cultures of Escherichia coli and S. aureus within 5 hr of exposure to concentrations at eight times the MIC. These results indicate a potential clinical role for lomefloxacin in the treatment of genitourinary tract infections caused by Gram-positive and Gram-negative bacteria, respiratory tract infections caused by susceptible organisms, and soft tissue infections caused by S. aureus.

Chlamydia trachomatis infection in a gynaecology clinic population: identification of high-risk groups and the value of contact tracing

Of 1267 women attending a gynaecology clinic, who were screened for the presence of Chlamydia trachomatis, 45 (3.6%) were found to be infected. Infection with C. trachomatis was more common in women who were less than or equal to 25 years of age, unmarried, nulliparous, requesting termination of pregnancy, using oral contraception as opposed to barrier methods, and who had cervical ectopy or cervicitis. Using contact tracing techniques 35% of male sexual partners of women who harboured C. trachomatis were also found to be infected. 86% of these men were symptomless. Asymptomatic chlamydial infection is common in men as well as women. Selective screening to identify women at risk of infection and the use of contact tracing to identify symptomless men with chlamydial infection are shown to be of value.

The use of a monoclonal antibody serotyping system in the study of the epidemiology of Pseudomonas aeruginosa

A monoclonal antibody method was used as a primary O serotyping method for 1084 isolates of Pseudomonas aeruginosa, using commercially available antibody reagents in slide agglutination tests with whole-cell antigen. Differences in distribution of serogroups were found between various hospitals in the district. Serotyping provided useful information in the investigation of suspected incidents of cross-infection. Colonization at multiple sites, or over periods of time, in a single patient usually involved only a single serogroup.

Efficacy of ofloxacin in the treatment of non-gonococcal urethritis in men and genital infections caused by Chlamydia trachomatis in men and women

The efficacy of ofloxacin was evaluated in 30 men with non-gonococcal urethritis (NGU) and 17 women with Chlamydia trachomatis infection of the cervix. All were treated with ofloxacin 200 mg twice daily for seven days. Before treatment, Ch. trachomatis was isolated from 11 (37%) of the 30 men with NGU. Of these 30 men, the symptoms and signs of urethritis were eliminated in 20 (67%) two weeks after completion of ofloxacin therapy. Ch. trachomatis was not re-isolated from any of the 11 men with positive isolation before treatment. All of the group of 17 women with Ch. trachomatis infection of the cervix had complete cure two weeks after completion of ofloxacin treatment. Ofloxacin appears to be an effective treatment for lower genital tract infections with Ch. trachomatis in men and women and its efficacy in NGU appears to be comparable to standard tetracycline therapy.

The comparative in-vitro activity of ofloxacin

The antibacterial activity of ofloxacin, a new fluoroquinolone, was evaluated against a wide range of clinical bacterial isolates and compared with that of nalidixic acid, norfloxacin, enoxacin, pefloxacin and ciprofloxacin by determination of minimum inhibitory concentrations (MICs). Ofloxacin was very active against nalidixic acid-susceptible isolates of the Enterobacteriaceae (MIC less than or equal to 0.12 mg/l) and was also active against strains resistant to nalidixic acid (MIC less than or equal to 2 mg/l). The activity was similar to norfloxacin, enoxacin and pefloxacin but some four-fold less than that of ciprofloxacin. All of the fluoroquinolones were highly active against Vibrio cholerae (MIC less than or equal to 0.015 mg/l), V. parahaemolyticus (MIC less than or equal to 0.12 mg/l) Aeromonas hydrophila (MIC less than or equal to 0.03 mg/l), Plesiomonas shigelloides (MIC less than or equal to 0.015 mg/l), Campylobacter jejuni (MIC less than or equal to 0.5 mg/l), Neisseria spp., Haemophilus influenzae, H. ducreyi, Bordetella pertussis and Legionella pneumophila (MIC less than or equal to 0.06 mg/l for all species). Ofloxacin, ciprofloxacin and pefloxacin (MIC less than or equal to 1, 2 and 2 mg/l, respectively) showed similar activity against Staphylococcus spp. and were somewhat more active than enoxacin (MIC less than or equal to 4 mg/l) and norfloxacin (MIC less than or equal to 8 mg/l). Ofloxacin was moderately active against beta-haemolytic Streptococcus spp. (MIC less than or equal to 2 mg/l), Corynebacterium diphtheriae (MIC less than or equal to 1 mg/l) and Cory. jeikeium (MIC less than or equal to 2 mg/l) and somewhat less active against alpha- and non-haemolytic Streptococcus spp., Str. pneumoniae and Listeria monocytogenes (MIC less than or equal to 4 mg/l for all species) and Str. faecalis (MIC less than or equal to 8 mg/l). The activity of ofloxacin, against these species, was similar to ciprofloxacin and four to eight times greater than norfloxacin, enoxacin and pefloxacin. Ofloxacin, and all of the fluoroquinolones, were less active against anaerobic than aerobic bacteria. Clostridium perfringens (MIC less than or equal to 1 mg/l) was more susceptible to ofloxacin than were other anaerobic species and Cl. difficile (MIC less than or equal to 16 mg/l) was more resistant. Ofloxacin was the most active compound tested against Chlamydia trachomatis SA2f (MIC less than or equal to 0.5 mg/l) with only ciprofloxacin (MIC less than or equal to 1 mg/l) approaching similar activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Cross-infection between animals and man: possible feline transmission of Staphylococcus aureus infection in humans?

An outbreak of epidemic methicillin-resistant Staphylococcus aureus occurred on a rehabilitation geriatric ward. Intensive screening of patients and staff revealed an unusually high carriage rate in the nursing staff (38%), thought to be related to a ward cat which was heavily colonized from the environment. Infection control measures and removal of the cat led to rapid resolution of the outbreak.

In vitro activity of sulphamethoxazole/trimethoprim and sulfadoxine/pyrimethamine against Chlamydia trachomatis SA2f in McCoy cell culture

Chequerboard titrations of sulphamethoxazole/trimethoprim and sulfadoxine/pyrimethamine were performed against Chlamydia trachomatis (strain SA2f) using McCoy cell monolayers in vials. The experiments were continued for ten passages each. The mean fractional inhibitory concentration index for each combination was calculated. Results demonstrated synergistic activity between sulphamethoxazole and trimethoprim, and between sulfadoxine and pyrimethamine.

Isolation of Chlamydia trachomatis from endometriums of women with and without symptoms

Chlamydia trachomatis was isolated from the endometrial cavities of three out of 19 women with positive cervical cultures, who were all symptomless sexual contacts of men with non-gonococcal urethritis (NGU). C trachomatis was recovered from the endometrial cavities of four out of 14 women with pelvic inflammatory disease (PID), three of whom had positive cervical cultures. Although endometrial biopsy is probably not justifiable as a routine procedure, it may be a useful adjunct to endocervical investigations for managing women with PID.

Database handling for infection control and hospital epidemiology

In 1977 the Department of Microbiology, University College Hospital, London introduced an integrated data processing system. The system was designed primarily to produce individual reports on specimens processed. Input was via visual display units (VDU's) using nmemonic codes. Additionally data is sorted by the software to provide daily, weekly, monthly and annual listings for epidemiological use. Listings concerning specific problem area can be produced as required. As computing power and data storage systems become cheaper it should be possible to improve upon the quality of epidemiological information available. A continuous surveillance system is envisaged where each day all potential outbreaks are displayed and help with their management is offered. Information on incidence of infections and changing trends (such as anti-microbial resistance patterns) would be instantly available in numerical and graphical form. Modern colour VDU's and new programming techniques would make the system especially easy to use by the untrained operator.

A review of the in-vitro activity of roxithromycin against genital pathogens

The in-vitro activity of roxithromycin against Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Treponema pallidum, Gardnerella vaginalis and Haemophilus ducreyi is reviewed. Roxithromycin demonstrated equivalent activity to erythromycin against N. gonorrhoeae, C. trachomatis, M. hominis, U. urealyticum, G. vaginalis and H. ducreyi. In a rabbit model for syphilis, potentially useful activity against T. pallidum has been demonstrated.

The in-vitro activity of doxycycline and minocycline against anaerobic bacteria

The likelihood of bacterial resistance now prevents the use of oxytetracycline in the empirical therapy of anaerobic infections. This study investigates the in-vitro activity of two semi-synthetic derivatives, doxycycline and minocycline, against a range of anaerobic bacteria. MICs for each antibiotic were determined by an agar incorporation technique. Doxycycline and minocycline were four to eight times more active against the majority of strains than oxytetracycline. With the exception of Bacteroides bivius, almost 90% of strains were inhibited by 4 mg/l of doxycycline or minocycline, but resistance to the same concentration of oxytetracycline was present in 60% of the B. fragilis group, 30% of Peptostreptococcus spp. and 24% of Clostridium perfringens. Doxycycline and minocycline represent an alternative therapy for anaerobic infections where bacterial sensitivities are known.