During a 6-month period, 892 positive blood cultures were detected in the Copenhagen County hospitals. 302 (34%) were regarded as contaminations, and of the remaining cases 419 (71%) were community-acquired and 171 (29%) hospital-acquired, giving incidence rates of 6.8/1,000 admissions and 2.8/1,000 admissions, respectively. Both frequency and rate of hospital-acquired bacteremia were lower compared to most other studies. E. coli was more commonly found in community-acquired infections, while coagulase-negative staphylococci were the organisms most often considered as a contaminant. The main causative organisms in hospital-acquired infections were S. aureus (n = 37) and E. coli (n = 34). The proportion of polymicrobial bacteremias in this study was lower compared to most other studies (8%). E. coli from hospital-acquired infections were resistant to ampicillin in 42% of cases, but other Enterobacteriaceae showed higher percentage of resistance to beta-lactam antibiotics. S. aureus was penicillin-resistant in 92% of cases, but no methicillin-resistant strains were isolated. The frequency of antibiotic resistance was low compared to reports from other countries. A total of 136 hospital-acquired cases were followed prospectively. 61% of the patients were male and 46% were > or = 60 years of age. Most patients had predisposing diseases, 90% had foreign body and/or recent surgery performed, and 74 (54%) had an intraveneous catheter. The portal of entry was known in 132 (97%) of the cases, the most common being the urinary tract (42%), followed by an intravenous catheter (30%). The prevalence of urinary tract catheters gave an increased number of cases with E. coli bacteremia. The mortality was 16%.
In patients treated with cytotoxic drugs granulocytopenia and septicemia are commonly seen. In this 10-year survey 324 blood culture isolates from 184 patients with hematological diseases and septicemia were studied. The distribution of microbiological diagnoses in patients with hematological diseases as well as acute leukemia 1980-1986 was significantly different (p less than 0.01) from an unselected blood culture material from the same period. The differences are mainly seen between Enterobacteriaceae other than Escherichia coli, Pseudomonas aeruginosa and staphylococci. The microbiological spectrum for patients with hematological disease 1987-1989 was also significantly different (p less than 0.05) from the spectrum of the same group of patients 1980-1986 due to higher frequencies of coagulase-negative staphylococci and alpha-streptococci and lower frequency of E. coli in the latter period. 40% of the isolates were gram-positive cocci during the first period and increased to 50% during the second period. The susceptibility testing indicates that trimethoprim/sulfonamide is not as good a choice as ciprofloxacin or norfloxacin for oral antibiotic prophylaxis. For intravenous therapy imipenem/cilastatin or the combinations of an aminoglycoside/piperacillin or aminoglycoside/third generation cephalosporin have advantages over aminoglycoside/trimethoprim/sulfa in combination. However, addition of isoxazolylpenicillin or vancomycin now seems necessary to cover the increasing part of gram-positive bacteria causing septicemia in patients with hematological disease.
The cultural characteristics of 1220 Campylobacter strains from a variety of sources are described. Forty-two were identified as Campylobacter fetus ssp. fetus (Véron & Chatelain, 1973), 1120 as members of the C. jejuni/C. coli group, and 58 did not conform to any known description. Sixteen of the latter strains had the basic characteristics of C. fetus but were atypical in certain other respects. The other 42 strains had the thermophilic characteristics of the jejuni/coli group, but were resistant to nalidixic acid and had other features in common; it is possible that they represent a new species. They were isolated from 19% of locally caught wild seagulls but only occasionally from other animals and man.Growth at 25 degrees C clearly distinguished strains of C. fetus from those of the jejuni/coli and the nalidixic acid-resistant thermophilic (NARTC) groups. Maximum growth temperature was less reliable for this purpose, and 43 degrees C was found to be better than the traditional 42 degrees C. By arranging the results of three tests (tolerance to 2,3,5-triphenyltetrazolium chloride, growth at 30.5 and 45.5 degrees C) serially in the form of a schema comprising nine categories, the jejuni/coli strains fell into two main groups resembling the Institute Pasteur C. jejuni and C. coli type strains, but these groups could not be clearly defined owing to the existence of strains with intermediate characteristics.Most of the strains from cattle resembled C. jejuni, whereas those from pigs resembled C. coli; poultry strains occupied a more intermediate position. Strains from man and other animals were of mixed types, but most human strains resembled C. jejuni rather than C. coli. The type distribution pattern that most nearly matched that of human indigenous strains was given by a half-and-half mixture of strains from cattle and poultry.
Cites: J Pediatr. 1973 Mar;82(3):493-54572934
Cites: Br Med J. 1977 Jul 2;2(6078):9-11871765
Cites: Can J Microbiol. 1977 Sep;23(9):1311-371191
We report the results of a province-wide quality control program in which five methicillin-resistant Staphylococcus aureus strains were circulated to all Ontario laboratories (hospital, private, and public health laboratories) on nine occasions between 1980 and 1989. The level of expression of methicillin resistance in each of the isolates was determined by performing viable colony counts on serial dilutions of methicillin in agar, and each isolate was assigned to an expression class according to previous published criteria (A. Tomasz, S. Nachman, and H. Leaf, Antimicrob. Agents Chemother. 35:124-129, 1991). Over this time there was an improvement in the performance of laboratories in the recognition of three strains that were relatively easy to detect (strains B, C, and E). These strains were of expression class II, and 98% of laboratories reported correct identifications in 1986. Performance in identifying two strains (strains A and D) of expression class I remained poor. Strain A was circulated in two surveys in 1987 and 1989, and laboratories were sent a questionnaire requesting details of the methods used in those two surveys. The methods used by the laboratories were classified into three categories: disk diffusion, single-plate screening by agar incorporation, and automated methods, which included premanufactured MIC panels. Between the 1987 and 1989 surveys, there was no change in the performance of the disk diffusion test (60% correct on both occasions), but there was improvement in the sensitivity of the agar incorporation test (36% correct in 1987 and 84% correct in 1989) and in automated methods (43% correct in 1987 and 79% correct in 1989). Over a decade, there was overall improvement in the performance of laboratories in detecting easy-to-detect strains, but there were difficulties in detecting organisms of low expression class, and an organism of very low expression class should be designated as a control organism for routine testing of methicillin-resistant s. aureus isolates.
The comparative analysis of 133 S. typhi clinical strains isolated from patients and carriers in Dnepropetrovsk Province in 1978-1987 was carried out. As shown by this analysis, 10 Vi phage types were represented in the set of strains under study, phage types A and F1 being the most numerous ones. Phage type F1 occurred less frequently among the strains isolated from carriers. 31.1% of the strains were found to contain plasmids with different molecular weight ranging from 96 to 0.5 MD. The occurrence of plasmid-containing strains remained at the same level during the whole period under study. Low-molecular plasmids occurred more frequently in the strains isolated from carriers. The minimal suppressive concentrations of a number of antibiotics, such as penicillin, ampicillin, monomycin, chloramphenicol, tetracycline, rifampicin and streptomycin, were determined. 7% of the strains were resistant to penicillin, 9% to monomycin, 15%--to tetracycline and 2.6% to chloramphenicol. The correlation between penicillin and monomycin resistance of the strains and the presence of the plasmid with a molecular weight of 60 MD in these strains was established. All strains were shown to be highly variable in the degree of their virulence: from 10(2) to 10(8). The strains isolated from patients possessed greater virulence.
The oral cavity is the ecological niche for Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus, but occasionally they cause severe nonoral infections. In this study we present 20 systemic or nonoral infections due to A. actinomycetemcomitans and H. aphrophilus, comprising all isolates of these species forwarded to and stored in Finnish reference laboratories during the years 1988-2000. The time from specimen collection to correct species identification was 9.3 days for A. actinomycetemcomitans and 10.7 days for H. aphrophilus. A. actinomycetemcomitans strains represented serotypes a, b, c, and d. Arbitrarily primed PCR distinguished four A. actinomycetemcomitans and six H. aphrophilus genotypes. Antimicrobial susceptibility testing with benzylpenicillin, amoxicillin, tetracycline, metronidazole, azithromycin, and trovafloxacin showed generally good activities against the present strains, and the susceptibility patterns closely resembled those of oral strains. The prolonged time to recover and identify A. actinomycetemcomitans and H. aphrophilus from systemic and nonoral infections may delay the correct diagnosis of the patient, but the good antimicrobial efficacies of antimicrobial agents against these pathogens give a good prognosis for the patients and advance the treatment of severe infections caused by these fastidious organisms of oral origin.
Activity of macrolides, lincosamines, streptogramins and fluoroquinolones against streptococcus pneumoniae and enterococci isolates from the western hemisphere: example of international surveillance (SENTRY antimicrobial surveillance program )in the development of new drugs.
Resistance among commonly isolated Gram-positive cocci have compromised the available therapeutic regimens and require structured monitoring at the local, regional, national, and international levels. Two popular treatment classes of antimicrobials (macrolides-lincosamines-streptogramins [MLS], fluoroquinolones) have been tested against 3, 049 isolates of Streptococcus pneumoniae and enterococci from the SENTRY Antimicrobial Surveillance program. The strains were obtained from clinical cases in hospitals in the United States, Canada, and six nations (10 medical centers )in Latin America. MLS and fluoroquinolone compounds had moderate activity against vancomycin-susceptible Enterococcus faecalis only (gatifloxacin, and trovafloxacin MIC(50), 0.5 microg/ml), and quinupristin/dalfopristin was potent only against E.faecium isolates (MIC(90), 1 microg/ml(-2) microg/ml). When tested against pneumococci, gatifloxacin, trovafloxacin, sparfloxacin, and quinupristin/dalfopristin (MIC(90), or =99.8% and 84.7% to 99.1% of strains, respectively. These results from a global resistance monitoring program should encourage rapid drug development. Based on in vitro sensitivity testing, they indicate a promising role for the treatment of emerging resistant Gram-positive cocci. The clinical role for each new agent will depend on safety profiles, rates of administration, and other issues identified during development in the clinical trials process.