Dealing with waterborne disease in Canada: challenges in the delivery of safe drinking water.

Protecting the public from waterborne diseases is an environmental health responsibility that every government worldwide must deal with. Canada's recent experience with waterborne outbreaks has brought the effectiveness of its water-monitoring and treatment systems under scrutiny. This paper focuses on microbial waterborne diseases and the shortcomings of drinking-water systems, dividing them into source control, monitoring, treatment, and operation, epidemiologic, and risk communication issues. Whereas some of these issues are often addressed, others, such as risk communication issues, are less frequently included in drinking water-management plans. Lessons can be learned from the Canadian experience, as these issues are applicable worldwide and especially in the developed world.

Synergistic interactions of ciprofloxacin and extended spectrum beta-lactams or aminoglycosides against Acinetobacter calcoaceticus ss. anitratus.

The susceptibility of 54 clinical isolates of Acinetobacter calcoaceticus ss. anitratus to 16 antimicrobial agents was determined in vitro with inoculum of 10(4) and 10(6) cfu by a standard agar dilution method. The most active agents were imipenem, SCH 34343, ciprofloxacin, difloxacin (A-56619), and A-56620. Only imipenem and Abbott quinolones (A-56619 and A-56620) remained active when tested with the heavier inoculum. Except for ticarcillin and ceftazidime, which showed only moderate activity, the extended-spectrum penicillins and cephalosporins, as well as aztreonam and aminoglycosides, were inactive against these highly resistant strains. Nine isolates were selected for combination studies of ciprofloxacin with seven beta-lactams and three aminoglycosides using a checkerboard agar dilution technique. Synergistic or additive interactions at clinically achievable concentrations were more common with amikacin (eight isolates), tobramycin (seven), ceftazidime (six), cefoperazone (six), and aztreonam (six), than with other agents, including mezlocillin (four), piperacillin (three), gentamicin (two), and cefsulodin (two). Antagonism was rare, only occurring with mezlocillin in a single strain. These data suggest that combinations of ciprofloxacin with these agents may be useful for some nosocomial multidrug resistant A. calcoaceticus ss. anitratus infections.

Point-of-sale glass bottle recycling: indoor airborne exposures and symptoms among employees.

AIMS: To assess the impact of newly introduced point-of-sale glass bottle recycling on indoor air quality and employee health. METHODS: Airborne exposures and both chronic and acute respiratory and somatic symptoms were surveyed among 226 employees at 36 randomly selected liquor stores with bottle recycling and in-house glass breaking. Each store was visited twice; between visits glass breaking was discontinued for one month in half the stores (selected at random), although bottles were still collected and stored on site. Rates of chronic symptoms were compared to an external, unexposed control population. RESULTS: Geometric mean exposure levels were 0.18 mg/m3 for inhalable particulate matter and 3.6 EU/m3 for endotoxin (270 personal samples); 1064 CFU/m3 for viable fungi (648 area samples). Fungal levels were associated with visibly mouldy bottles being broken, outdoor fungal counts, and uncovered glass bins. Exposures were not altered by the intervention of shutting down glass breaking machinery. Compared to controls, employees reported more work related chronic chest tightness and chronic nasal symptoms. Acute chest symptoms were associated with breaking visibly mouldy bottles, but not with measured fungal counts. Inhalable particulate matter levels >0.2 mg/m3 were associated with acute upper airway irritation. Somatic symptoms were associated with measures of psychosocial job strain. CONCLUSION: Results suggest that this type of recycling programme may generate fungal exposures sufficient to elicit upper airway and chest symptoms.

Vaginal colonization of Escherichia coli and its relation to contraceptive methods.

The prevalence rate of vaginal colonization with E. coli was studied prospectively among 495 healthy premenopausal women, and factors associated with vaginal carriage of E. coli were examined. Vaginal colonization with E. coli was found in 12% of women, and was significantly correlated with phase of the menstrual cycle (p less than 0.05), prior use of antibiotics (p less than 0.05), current genital complaints (p less than 0.05), history of previous urinary tract infection (p less than 0.001), and use of diaphragm or cervical cap for contraception (p less than 0.005). The high prevalence rate among diaphragm or cervical cap users remained significant when other confounding factors were kept constant (p less than 0.05). This observation may explain the association of diaphragm use and urinary tract infection demonstrated in previous epidemiologic studies and confirmed in the present study (p less than 0.05).

PIP: The prevalence rate of vaginal colonization with E. coli was studied prospectively over the January-April 1982 period among 495 healthy premenopausal women, and factors associated with vaginal carriage of E. coli were examined. The study was conducted at the University of British Columbia Student Health Service. A confidential questionnaire was administered for information regarding present sexual activity, methods of contraception, menstrual hygiene, previous history of genital and urinary tract infections, and recent antibiotic use. A manual pelvic examination was performed and vaginal culture was obtained. 28% of the women were seen in the Clinic because of genital symptoms including vaginal discharge with or without irritation, abnormal menstruation, or pelvic pain. 71% of the women attended the Clinic for an annual physical examination and had no genital complaints. E. coli was isolated in 61 women (12%). Other Enterobactericeae were cultured from 6 additional women. Factors significantly associated with vaginal colonization of E. coli included phase of the menstrual cycle, prior use of antibiotics, previous history of urinary tract infection, concurrent presence of gential complaints, and use of diaphragm or cervical cap contraceptive method. Difference in prevalence rates of vaginal E. coli in women using diaphragm or cervical cap compared to rates among women using other contraceptive methods remained statistically significant when other confounding factors such as phase of menstrual cycle, presence of genital complaints, previous history of urinary tract infection, or prior use of antibiotics were kept constant. No significant correlation with vaginal E. coli was observed regarding prior vaginal infection within 2 weeks, sexual activity, intercourse during menstruation, or use of vaginal douche or spray.

Methanol exposure to car occupants from windshield washing fluid: a pilot study.

UNLABELLED: Automobile occupants might be exposed to considerable amounts of methanol from previously unreported source, namely via the inhalation of vapors of winter-grade, methanol-based, windshield washing fluid that drains to the intake air ducts of the car. Air samples were collected in passenger cars during simulated operating conditions and analyzed for methanol via headspace gas chromatography-mass spectrometry, electron impact, selected ion monitoring. The method was linear in the 2-2000 ppm range. Concentrations exceeding 1000 ppm were recorded. PRACTICAL IMPLICATIONS: Using a winter-grade, methanol-based, windshield washing fluid for windshield cleaning in a passenger car can result in a methanol concentration in the air of the passenger cabin in excess of 1000 ppm. In view of the widespread use of this product, more studies are necessary to elucidate, in depth, the concentrations of methanol vapors which could be encountered in various weather and driving conditions as well as the concomitant contributing influences of car design. These studies are necessary to properly assess the hazards associated with use of the fluid and possible mitigation approaches which might include substitution of methanol by less toxic formulations.

Follow-up study of dogs and cats with asymptomatic Cryptococcus gattii infection or nasal colonization.

The pathogenesis of Cryptococcus spp. infection following nasal colonization is unclear. This article reports follow-up data on a cohort of seven cats and five dogs identified in a previous study as sub-clinically infected with Cryptococcus spp. or colonized by C. gattii. Two cats progressed to clinical disease within four to six months of initial detection of antigenemia and nasal cavity colonization. The ten other animals remained asymptomatic but many were repeatedly positive on cryptococcal antigen testing or nasal fungal culture suggesting protracted infection or colonization. The results indicate that asymptomatically infected animals may clear the organism, remain sub-clinically infected or progress to clinical disease. Factors influencing the transition from exposure to disease require further investigation.

Sub-clinical infection and asymptomatic carriage of Cryptococcus gattii in dogs and cats during an outbreak of cryptococcosis.

Since 1999, Cryptococcus gattii has emerged as an important pathogen of humans and animals in British Columbia, Canada. Nasal swabs and serum samples were collected from dogs and cats residing within the Coastal Douglas Fir biogeoclimatic zone on Vancouver Island, where clinical cases have been reported. Deep and superficial nasal fungal cultures of 280 dogs and 94 cats identified four (4.3%) cats and three (1.1%) dogs with C. gattii serotype B in their nasal cavity. Serum samples collected from 266 dogs and 84 cats identified six (7.1%) cats and two (0.8%) dogs with a positive cryptococcal antigen titer. Overall cats were 4.4 times more likely than dogs to be positive on one or both tests. Identification of sub-clinical infection and nasal colonization is an important step in the characterization of the outbreak of clinical cryptococcosis on Vancouver Island.

Sequential assessment of vaginal microflora in healthy women randomly assigned to tampon or napkin use.

The effect of tampon usage on the vaginal microflora of 35 healthy women was determined following their random allocation to either tampon or napkin use for three consecutive menstrual cycles. Sequential and semiquantitative vaginal cultures were obtained on days 3 +/- 2, 15 +/- 2, and 25 +/- 2 of the menstrual cycle (day 1, first day of menses) before and after randomization. Before randomization, the rate of isolation and median counts of facultative lactobacilli were significantly higher (P less than .05) and that of eubacteria was significantly lower (P = .026) among regular tampon users than among exclusive napkin users. After randomization, only median counts of coagulase-negative staphylococci were significantly increased (P = .025) during tampon use compared with the rates for the same women during napkin use. These shifts in vaginal microflora occurred only in samples obtained during menstruation and not in those obtained at other sampling times. The data presented here support the notion that the use of tampons may result in alterations in the autochthonous vaginal microflora. It remains to be determined if these ecologic shifts in the vaginal microflora may adversely affect resistance to colonization by potential pathogens in the lower female genital tract.

Aquarium pets as a source of antibiotic-resistant salmonellae.

Thirteen serotypes of Salmonella isolated from imported ornamental aquarium frogs, snails, and their waters were shown to be multi-drug-resistant. Among the resistances exhibited were resistance to gentamicin, sulfamethoxazole-trimethoprim, cephalothin, and nalidixic acid. Frog isolates displayed eight different patterns and snails isolates had two different resistance patterns. The most common serotype, Salmonella typhimurium, was resistant to 18 antibacterials while other salmonellae were resistant to 9 to 16 antibacterials. Resistances in S. typhimurium and S. bovis-morbificans were conjugative and a number of R plasmids participated in the resistance. The plasmid-mediated resistance in S. typhimurium was stable and the levels of resistance conferred were markedly higher than in the other salmonellae tested. Resistance of other serotypes was non-conjugative and resistance to the beta-lactam antibiotics was unstable.

Plasmid-specified sucrose fermentation in Salmonella arizonae.

Thirty cultures of Salmonella arizonae 47:r:253 (Ar 23:24-25) were isolated over 7 months from the faeces of a captive reptile. All were unusual in their inability to produce a positive o-nitrophenyl-beta-D-galactosidase reaction, and in their ability to ferment sucrose. These S. arizonae carried a plasmid having a molecular mass of 72 megadaltons which specified tetracycline resistance and a plasmid of 5 megadaltons which coded for the ability to ferment sucrose. The small size of this sucrose plasmid clearly distinguishes it from others which have been reported.

Isolation of salmonellae and other potential pathogens from the freshwater aquarium snail Ampullaria.

The freshwater aquarium snail (Ampullaria spp.) was demonstrated to carry as many as 10(8) viable mesophilic bacteria per g of meat plus shell. Some 16 genera of bacteria were identified, with gram negatives predominating. Enrichment culture techniques enabled the isolation of salmonellae from 24 to 42 lots of 200 g each. The salmonellae comprised eight different serotypes, including Salmonella newport, Salmonella saint-paul, and Salmonella infantis. This association of salmonellae with snails may contribute to cases of human salmonellosis, since other aquarium species have already been shown to contribute to many such cases. The snails were also found to commonly harbor Pseudomonas aeruginosa and, occasionally, Edwardsiella tarda.

Comparative in-vitro activity of ceftazidime (GR-20263) and other beta-lactamase stable cephalosporins against anaerobic bacteria.

The in-vitro activity of ceftazidime was determined against 586 clinical isolates of anaerobic bacteria by an agar-dilution technique and compared with that of cefuroxime, moxalactam and cefoxitin. At 16 mg/l, only 60% of all isolates were inhibited by ceftazidime, compared to 79% by cefuroxime, 81% by moxalactam and 80% by cefoxitin. Ceftazidime was relatively inactive against Bacteroides fragilis group, Lactobacillus and Clostridium species other than Cl. perfringens. Peptococcus, Peptostreptococcus, Cl. perfringens, microaerophilic streptococci and Propionibacterium were readily inhibited. Moxalactam was the most active agent against Bact. fragilis group, while cefuroxime was the most active agent against Streptococcus and Lactobacillus.

Comparative in-vitro activity of ceftazidime (GR 20263) and other beta-lactamase stable cephalosporins against pseudomonas. Effect of inoculum size and divalent cation supplementation.

The anti-pseudomonal activity of ceftazidime was determined by an agar-dilution technique against 92 strains of Pseudomonas aeruginosa and 22 non-aeruginosa isolates and compared with that of cefoperazone, moxalactam and ceftizoxime. Against Ps. aeruginosa, ceftazidime and cefoperazone were comparable in activity and both were significantly more active than moxalactam and ceftizoxime (P < 0001). At 16 mg/l, 95% of strains were inhibited by ceftazidime, compared to 94% by cefoperazone, 80% by moxalactam and 25% by ceftizoxime. A three- to four-fold increase in geometric mean MIC for ceftazidime, moxalactam and ceftizoxime, and a 23-fold increase for cefoperazone was observed with a larger inoculum of 10(6) cfu, demonstrating a marked inoculum effect. Additionally, divalent cation (calcium and magnesium) concentrations of the test medium also influenced the in-vitro results for ceftazidime and cefoperazone, but not for moxalactam or ceftizoxime. Against non-aeruginosa strains, cefoperazone was most active while ceftizoxime was less effective.

Occurrence of potential pathogens in water containing ornamental fishes.

The bacterial population of the water supplied with ornamental fish purchased from retail outlets was examined qualitatively and quantitatively. As many as 10(9) viable aerobic organisms per 100 ml were present, with fecal coliform counts as high as 10(5) per 100 ml. Citrobacter, Escherichia, Pseudomonas, and Vibrio were isolated from 75% or more of the samples, whereas Aeromonas, Alcaligenes, Enterobacter, Flavobacterium, and Streptococcus were isolated from 45 to 65% of the samples. Pseudomonas aeruginosa, Edwardsiella tarda, and Klebsiella pneumoniae were also isolated.

Isolation of Pseudomonas aeruginosa and other bacterial species from ornamental aquarium plants.

Ornamental aquarium plants were demonstrated to carry as many as 10(8) viable mesophilic bacteria per g. Gram-negative organisms predominated among the 19 genera of bacteria identified. Pseudomonas aeruginosa was readily isolated from 53% of the samples tested.

Antibacterial activity of tropilidine and tropone.

The seven-membered ring compounds tropilidine and tropone were shown to be bacteriostatic and bactericidal for a wide range of bacterial species.

Detection and quantitation of toxic shock syndrome toxin 1 in vitro and in vivo by noncompetitive enzyme-linked immunosorbent assay.

Toxic shock syndrome toxin 1 (TSST-1), an exotoxin produced by many Staphylococcus aureus strains, is implicated as the prime causal agent of toxic shock syndrome (TSS). A sensitive and specific noncompetitive enzyme-linked immunosorbent assay (ELISA) capable of detecting TSST-1 at concentrations from 0.5 to 16 ng/ml was developed. This assay did not detect other staphylococcal enterotoxins including A, B, C1, C2, C3, D, and E. Possible interactions with protein A were readily eliminated by pretreatment of test samples with 10% normal rabbit serum. The assay was adapted for rapid screening of TSST-1 production by S. aureus isolates in culture supernatants in vitro and for detection of TSST-1 in vaginal washings of TSS patients and healthy controls in vivo. All 35 S. aureus isolates confirmed to be TSST positive by Ouchterlony immunodiffusion and 59 of 60 isolates confirmed to be TSST-1 negative gave concordant results by ELISA. Interestingly, toxigenic S. aureus strains isolated from TSS patients quantitatively produced significantly more TSST-1 in vitro compared with toxigenic control strains (P less than 0.05, Mann-Whitney rank sum test). TSST-1 could be detected by ELISA in three of four vaginal washings collected within 3 days of hospitalization from three women with acute menstrual TSS, compared with 0 of 17 washings from nine TSS patients hospitalized longer than 3 days (P = 0.003, Fisher's exact test) and 1 of 15 washings from 14 healthy control women (P = 0.016). This noncompetitive ELISA should be particularly useful for rapid screening of TSST-1 production by S. aureus isolates, for the purification and biochemical characterization of TSST-1, and for human and animal studies of the pathogenesis of TSS.

Comparison of susceptibility of gentamicin-resistant and -susceptible "Acinetobacter anitratus" to 15 alternative antibiotics.

Fifty-four clinical isolates of "Acinetobacter anitratus" separated cleanly into gentamicin-susceptible (16 strains) and gentamicin-resistant (38 strains) subpopulations. When tested with a 10(4)-CFU inoculum, gentamicin resistance was associated with a greater than fourfold increase in the MICs of norfloxacin, ciprofloxacin, A-56620, tobramycin, and amikacin for 50% of the strains. Antimicrobial agents with MICs for 90% of gentamicin-resistant strains in the susceptible range were ciprofloxacin, A-56619, A-56620, imipenem, SCH-34343, ceftazidime, aztreonam, carbenicillin, ticarcillin, and piperacillin. These agents may be useful alternative drugs for treating infections caused by aminoglycoside-susceptible and -resistant "A. anitratus."

Serologic responses to toxic shock syndrome (TSS) toxin-1 in menstrual and nonmenstrual TSS.

Toxic shock syndrome toxin-1 (TSST-1) is implicated as the major exotoxin associated with menstrual toxic shock syndrome. The role of TSST-1 in nonmenstrual TSS is less certain. We examined serum IgG responses to TSST-1 in 16 nonmenstrual (9 female, 7 male) and 14 menstrual TSS patients, and in 87 women and 66 men as age-matched healthy controls, using an enzyme-linked immunosorbent assay (ELISA). Relative ELISA titers were expressed as percent activity of a mid level serum standard tested concurrently. Based on 95% confidence estimates for predicting a negative titer (20.6 +/- 8.2%) using sera in which TSST-1 specific IgG was demonstrated to be absent by western blot, 24% of control women and 9% of control men lacked TSST-1 specific IgG in the random survey (p less than 0.05, Fisher's exact test). Relative titers in acute sera of menstrual TSS women (26.2 +/- 5.2%, mean +/- S.E.), but not nonmenstrual TSS women (71.8 +/- 18.6%), were significantly lower than those of control women (78.9 +/- 7.3%, p less than 0.01, Mann-Whitney test). Acute titers from male TSS patients (37.0 +/- 15.6%) were also significantly lower than those in control men (114.6 +/- 11.0% (p less than 0.05). Antibody titers from menstrual TSS women and TSS men remained low during convalescence. Nevertheless, seroconversion to TSST-1 was demonstrated by western blot in 7 of 10 patients in whom TSST-1 positive S. aureus was isolated, but in neither of two patients without toxigenic S. aureus.(ABSTRACT TRUNCATED AT 250 WORDS)

Synergistic interactions of ciprofloxacin and extended-spectrum beta-lactams or aminoglycosides against multiply drug-resistant Pseudomonas maltophilia.

The susceptibility of 28 clinical isolates of Pseudomonas maltophilia to 16 antimicrobial agents was determined in vitro by a standard agar dilution method with inoculum sizes of 10(4) and 10(6) CFU. All isolates exhibited multiple drug resistance. Nine isolates were selected for studies of combinations of ciprofloxacin with seven antipseudomonal beta-lactams and three aminoglycosides by a checkerboard agar dilution technique. Synergistic or additive combinations of ciprofloxacin in clinically achievable concentrations were most frequent with mezlocillin (89%), followed by cefoperazone (67%), piperacillin (56%), cefsulodin (56%), and ceftazidime (33%), and were infrequent with aztreonam (11%), the aminoglycosides (0 to 14%), or imipenem (0%). Antagonism was not observed in any combination. These data suggest that combinations of ciprofloxacin with these agents may be useful for some nosocomial multiply drug-resistant P. maltophilia infections.