Adherence, enterotoxigenicity, invasiveness and serogroups in Campylobacter jejuni and Campylobacter coli strains from adult humans with acute enterocolitis

Two hundred Campylobacter jejuni and Campylobacter coli strains from the same number of adult Swedish patients with acute enterocolitis were tested regarding adherence to and invasiveness in HEp-2 cells and for enterotoxigenicity by the CHO-cell assay. The serogroup characteristics, heat-stable and heat-labile, for each strain were also investigated. Eighty-four percent of the strains were classified as C. jejuni and 16 percent as C. coli. All of the strains were adherent to HEp-2 cells, 39% were invasive and 31.5% enterotoxigenic. We found significantly more invasive strains in the non-enterotoxigenic group than in the enterotoxigenic one. There would seem to be no correlation between enterotoxigenicity or invasiveness and serogroup. The results of this study suggest the existence of multiple mechanisms for C. jejuni- and C. coli-induced diarrhoea and that the mechanisms may differ from one strain to another.

Enterotoxigenicity and frequency of Campylobacter jejuni, C. coli and C. laridis in human and animal stool isolates from different countries

Campylobacter jejuni and C. coli strains were collected during three different years from adult patients with enterocolitis in Sweden (n = 372) from 49 patients in Kuwait, and Campylobacter strains from hens from Mexico, Pakistan and Sweden (n = 107) and Swedish pigs (n = 47). C. jejuni was the predominant species in human and hen isolates, and C. coli in pigs C. coli was significantly more common in human isolates from Sweden, and more common in hen isolates from Pakistan, than in hens from Sweden and Mexico. C. laridis was only isolated from pigs (17%) and was in no case enterotoxigenic. Both in human and hen isolates, C. jejuni strains were more enterotoxigenic than C. coli strains. C. jejuni strains from Swedish hens were less enterotoxigenic than those from Pakistan and Mexico (P less than 0.001), and strains from pigs were less enterotoxigenic than those from hens (P less than 0.001). We conclude that C. jejuni are more often enterotoxigenic and possibly more virulent than c. coli and C. laridis. The relative frequency of C. jejuni and C. coli in humans and animals differs from one country to another.

Intravenous ciprofloxacin and ceftazidime in serious infections. A prospective, controlled clinical trial with third-party blinding

Oral ciprofloxacin has been shown to be effective in the treatment of infections due to gram-positive cocci and gram-negative rods. The efficacy and safety of intravenous ciprofloxacin was compared with that of intravenous ceftazidime in the treatment of 59 patients with well-documented serious infections in a prospective, controlled, randomized study with a third-party blinding. Thirty-three patients were treated with intravenous ciprofloxacin (200 mg every 12 hours, plus a daily extra placebo dose); 26 patients were treated with ceftazidime (1 g every eight hours). The severity of the infections, underlying diseases, and demographic features were comparable in both groups, although there were more men in the ciprofloxacin group. For ciprofloxacin/ceftazidime treatments, respectively, the evaluated infections were: pyelonephritis (16 patients/nine patients), pneumonia (three/five), soft-tissue infections (four/zero), spontaneous peritonitis (five/two), primary bacteremia (three/eight), and other (two/two). Isolated pathogens included: Escherichia coli (22/12), Klebsiella sp. (five/four), Pseudomonas aeruginosa (two/three), Haemophilus influenzae (one/one), Proteus mirabilis (two/zero), Proteus vulgaris (one/zero), Salmonella sp. (zero/two), Plesiomonas shigelloides (one/zero), and others (one/four). The clinical responses were cure or improvement in 31 ciprofloxacin cases/21 ceftazidime cases; failure, zero/four; and indeterminate, two/one. The bacteriologic responses were eradication in 28 ciprofloxacin cases/22 ceftazidime cases; persistence, one/three; and indeterminate, four/one. Mild intolerance occurred in three ciprofloxacin cases and two ceftazidime cases. A mild increase in serum hepatic enzymes was observed in two patients in each group. Superinfections occurred in five patients: enterococcal septicemia (zero/two) and urinary tract infections (one/two). The results presented suggest that intravenous ciprofloxacin is an effective and safe antimicrobial agent for the treatment of serious infections, with an efficacy comparable with that of ceftazidime, a broad-spectrum cephalosporin. An additional advantage seems to be a lower rate of superinfections.

Cohort study of intestinal infection with campylobacter in Mexican children

A cohort of 179 children under 5 years of age from a low-income urban community was followed up for a year to determine the incidence of symptom-producing and of diarrhoea-free campylobacter intestinal infections, and thus their illness-to-infection ratio. 66% of all children had at least one campylobacter infection, one-third of these being associated with diarrhoea. The annual incidence of all campylobacter infections was 2.1 episodes per child. The incidence was inversely related to age (r = -0.78 p less than 0.02). The illness-to-infection ratio, which in infants younger than 6 months was 1:2, was negatively associated with age (r = -0.7, p less than 0.02). Only symptom-producing infections occurring early in life seemed to protect against subsequent infections.

High incidence of subclavian dialysis catheter-related bacteremias

This retrospective cohort study reviews the incidence of bacteremia in 48 patients undergoing hemodialysis using subclavian vein dialysis catheters (SDC) as temporary vascular access. Twelve (25%) of these patients had catheter-related bacteremia, and the most frequently isolated organisms were coagulase-negative staphylococci. Three patients developed right-sided endocarditis and one of them died due to pulmonary embolism. The presence of possible risk factors for SDC-related bacteremia, including duration of catheterization and number of hemodialysis procedures, were not statistically different when patients with and without bacteremia were compared, with the exception of a significantly lower incidence of bacteremia among those patients receiving antibiotic therapy at the time of catheter insertion. The use of resterilized catheters was not a risk factor. Specific guidelines for SDC insertion and care were established and followed, after which the infection frequency was reduced to 7.5% (1 episode per 45.5 patient-weeks of catheter use) in this high-risk population.

Control of emergence of multi-resistant gram-negative bacilli by exclusive use of amikacin

Results of a three-year prospective study of amikacin as the only aminoglycoside used at the Instituto Nacional de la Nutrición "Salvador Zubirán" are presented. During the initial three-month baseline period, resistance to amikacin, gentamicin, and tobramycin among 870 gram-negative bacterial isolates was 3.2 percent, 17.4 percent, and 11.2 percent, respectively. In this period, the overall consumption of aminoglycosides was 69 percent for gentamicin, 30.5 percent for amikacin, and 0.5 percent for tobramycin. In the following period of exclusive amikacin use, sensitivity patterns of 9,344 gram-negative strains isolated over three years were recorded. During this period, amikacin constituted 99.3 percent of all aminoglycosides used. The percentage of gentamicin-resistant gram-negative strains declined to 7.4 percent (p less than 0.0001), whereas the percentage of amikacin-resistant strains did not change significantly. Quarterly trend analysis of aminoglycoside-resistant strains also demonstrated a significant decrease in gentamicin resistance (p less than 0.005) and an overall steady state of amikacin resistance. It is concluded that the exclusive use of amikacin was not accompanied by a significant increase in amikacin resistance during a three-year period, and may even lead to a decrease in resistance to gentamicin and tobramycin among most gram-negative organisms.

Analysis of epidemiologic markers of nosocomial Serratia marcescens isolates with special reference to the Grimont biotyping system

Seventy-one strains of Serratia marcescens obtained from hospitalized patients of the Instituto Nacional de la Nutricion in Mexico City and two Virginia hospitals (University of Virginia Medical Center and Norfolk General Hospital) were analyzed to find markers useful for the epidemiologic investigation of outbreaks with this organism. Biotyping with commercial microwell systems (API 20# system [Analytab Products, Plainview, N.Y.] and DMS Rapid NFT [DMS Laboratories, Inc., Flemington, N.J.]) was not useful. Biotyping with the system designed by Grimont (assimilation tests, pigment production, and the ability to reduce tetrathionate broth) was helpful to characterize all strains. Of the 37 Mexican strains, 36 belonged to biogroup A 5/8 and 32 were biotype A8b. The 34 strains from the Virginia hospitals were distributed among six different biogroups and 12 biotypes. Significant differences in antimicrobial susceptibility (50% MIC, microgram/ml) between Mexican and Virginia strains were seen with carbenicillin (256 versus 8), piperacillin (64 versus 4), amikacin (16 versus 2), gentamicin (2 versus 0.5), and tobramycin (16 versus 2). Some Mexican strains showed variability in the susceptibility to amikacin because they were low producers of 6'-N-acetyltransferase type I. The Mexican strains seemed to come from a hospital with cross-infection problems because most were isolated from urine, were multiresistant, and more nonpigmented; in contrast, the strains isolated at University of Virginia Medical Center represent the experience of a hospital with scattered S. marcescens infections. The Grimont biotyping scheme is a useful epidemiologic tool for the clinical microbiologist.

Detection of mycobacterial antigens in cerebrospinal fluid of patients with tuberculous meningitis by enzyme-linked immunosorbent assay

Culture and identification of Mycobacterium tuberculosis in cerebrospinal fluid (CSF) of patients with tuberculous meningitis is slow, and prognosis depends on early diagnosis and treatment. An enzyme-linked immunosorbent assay with commercial BCG and anti-BCG was designed to detect mycobacterial antigens in human body fluids. Absorbance at 405 nm was measured and readings greater than or equal to 0.20 were considered positive. The readings were above 0.20 for four patients with confirmed tuberculous meningitis and nine of twelve patients with probable tuberculous meningitis. In all but one of ten patients with meningitis of other causes and in eleven control subjects the readings were below 0.20. The specificity of the test was 95% and its sensitivity 81.25%.

Cholera-like enterotoxin produced by Campylobacter jejuni. Characterisation and clinical significance

The presence and clinical significance of enterotoxins produced by Campylobacter jejuni were investigated. The supernatant of a prototype virulent strain grown in supplemented medium induced intraluminal fluid secretion in rat ileal loop but not in rabbit ileal loop or the infant mouse assay. It induced elongation and increased intracellular cyclic AMP levels in Chinese hamster ovary cells. Toxin activity was blocked by cholera antitoxin and was destroyed by heat and high or low pH; its molecular weight is in the range 10(4)-10(5) daltons. Toxin production was detected in 24 of 32 C jejuni strains from patients with diarrhoea and 1 of 6 from carriers. Antibody response to autologous C jejuni somatic antigen was investigated in 19 subjects for whom serial serum specimens were available. A fourfold rise was observed in all 10 patients with enterotoxigenic C jejuni diarrhoea, in 1 of 3 patients with non-enterotoxigenic C jejuni, and in none of the symptomless carriers of non-enterotoxigenic strains. These findings demonstrate that C jejuni produces an enterotoxin that may be important in pathogenesis of diarrhoea.

Experimental Campylobacter diarrhea in chickens

An animal model for Campylobacter fetus subsp. jejuni enteritis was developed in 3-day-old chickens. Diarrhea was induced in 88% (22 of 25) of chickens inoculated with 9 X 10(7) bacteria given orally. The mean incubation time was 45 h (range, 24 to 72 h). Considerable weight loss was observed in the experimental group compared with the control group. Ninety bacteria was the minimal infective dose capable of inducing diarrhea in 90% of the chickens. Overall mortality was 32% (8 of 25). Light microscopy, immunofluorescence, and electron microscopy of the gastrointestinal tract of serially sacrificed chickens were performed in control and experimental groups. A moderate infiltration of mononuclear cells was observed in ileum and cecum in the experimental group, with no disruption of intestinal mucosa. By immunofluorescence and electron microscopy, campylobacter was located within the epithelial cells and phagocytosed to a greater degree by mononuclear cells of the lamina propria.