Therapeutic effect of antibiotics in the compromised host : an experimental study

The present study was performed in a model of Klebsiella pneumoniae pneumonia and septicemia in rats. This experimental model was used because in leukopenic patients septicemia is a real threat, and K.pneumoniae is one of the pathogens that may be recovered [68, 74, 99, 116, 122, 124]. The experimental design including the infectious disease model is described in chapter 2. The role of the antibiotic dosage schedule as a determinant of therapeutic activity was investigated in relation to various factors such as the severity of infection (chapter 3) , the presence of host defense factors (chapter 4), and the kinetics of antibacterial activity in vitro and in vivo for different classes of antibiotics (chapter 5) . From the three classes of antibiotics, the 8-lactams, the aminoglycosides and the quinolones, ceftazidime, gentamicin and ciprofloxacin were selected as investigational drug, respectively, because of their antibacterial activity against clinically important pathogens and their broad antibacterial spectrum. In addition, the in vitro susceptibility in terms of MBC values of the K.pneumoniae strain used was similar for the three drugs tested, which facilitated a good evaluation of their therapeutic efficacy. The therapeutic effect of ceftazidime, gentamicin and ciprofloxacin in relation to the duration of infection and the bacterial growth rate is described in chapter 6. Finally in chapter 7 the experimental results obtained are discussed with reference to the observations of other investigators. The chapters 3 through 6 represent the appendix papers

Methicillin-Resistant Staphylococcus aureus in Meat Products, the Netherlands

A new methicillin-resistant Staphylococcus aureus (MRSA) clone related to pig and cattle farming was detected in the Netherlands. We investigated the extent of S. aureus presence in meat and found 36 S. aureus strains in 79 samples. Two strains were MRSA; 1 was multilocus sequence type 398, the clone related to farming

Brushland tinamou

p. 271-314 [11] p. of plates : ill., maps ; 27 cm.Includes bibliographical references (p. 314)

Helicobacter species are not detectable by 16S rDNA PCR in bile from Dutch patients with common bile duct stones.

BACKGROUND: Some Helicobacter species colonize the intestinal tract. To explore the possible relation between Helicobacter spp. and gallbladder disorders, we have investigated their presence in bile of patients with biliary obstruction and dilatation of the bile ducts. METHODS: Bile was sampled from 31 Dutch patients with biliary obstruction identified by jaundice and dilatation of the bile ducts on ultrasound. Samples (n = 31) were obtained immediately following cannulation of the common bile duct (CBD) by endoscopic retrograde cholangiopancreatography (ERCP) (n = 29) or by peri-operative puncture of the gallbladder (n = 2). DNA was isolated from bile by binding to diatoms. Helicobacter spp. were detected by a sensitive (detection limit 1 CFU per reaction tube) 16S rDNA PCR with genus-specific primers. Duplicate samples were spiked with Helicobacter pylori DNA and subjected to PCR in order to check for inhibition. RESULTS: 28 patients had CBD stones (bile collected by ERCP (n = 26) or operatively (n = 2)), 2 had a pancreatic head tumor, and in 1 no abnormalities were found. In 1 of 21 amplifiable bile samples (10/31 inhibited) from Dutch patients with CBD stones, H. pylori 16S rDNA was found. CONCLUSION: Our data indicate that CBD stones in Dutch patients are not associated with the presence of Helicobacter spp. in bil

Parietal cell protrusions and fundic gland cysts during omeprazole maintenance treatment

Parietal cell protrusion (PCP), swelling and bulging of parietal cells, has been observed in the oxyntic mucosa of patients receiving omeprazole. The frequency of this event and the underlying mechanisms remain to be clarified. As such, it is unknown whether there is a relation with either serum gastrin or Helicobacter pylori infection, and whether PCP predisposes to the development of fundic gland cysts (FGC). We therefore investigated the development of PCP and FGC in gastroesophageal reflux disease (GERD) patients treated with omeprazole and correlated findings to duration of therapy, gastrin, and H pylori infection. In a randomized, double-blinded study, GERD patients were evaluated by endoscopy with biopsy sampling for histology and culture at baseline, and after 3 and 12 months' therapy with omeprazole 40 mg daily. H pylori-positive patients were randomized to additional eradication therapy or placebo antibiotics at baseline. All histological slides were scored blinded for time and outcome of culture for the presence of PCP and FGC. Fasting serum samples from all visits were used for gastrin measurements. The prevalence of PCP increased during omeprazole therapy from 18% at baseline to 79% and 86% at 3 and 12 months (P < .001, baseline v both 3 and 12 months). The prevalence of FGC increased from 8% to 17% and 35% (P < .05, baseline v 12 months). The prevalence of PCP and FGC did not differ among the H pylori-positive and H pylori-negative patients at baseline (PCP 16% v 20% and FGC 7% v 8%, respectively). Whereas H pylori eradication did not significantly affect development of PCP (P = .7), FGC developed significantly more often in the H pylori-eradicated patients when compared with persistent H pylori-positive patients (P < .05). PCP development was related to serum gastrin rise during therapy. In conclusion, PCP occurs in most patients within the first months of omeprazole treatment and is related to increased gastrin levels. FGC develops more gradually and is enhanced by H pylori eradication. (C) 2000 by W.B. Saunders Company

Extensive dissemination of extended spectrum β-lactamase-producing Enterobacteriaceae in a Dutch nursing home

OBJECTIVE: Risk factors for rectal carriage of ESBL-E and transmission were investigated in an outbreak of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E). DESIGN: Rectal carriage of ESBL-E was determined in a cross-sectional survey by culture of perianal swabs or fecal samples. Both phenotypical and genotypical methods were used to detect the production of ESBL. Nosocomial transmission was defined as the presence of genotypically related strains in ≥2 residents within the NH. Patient characteristics and variables in infection control practices were registered to investigate risk factors for transmission. SETTING: A nursing home (NH) in the southern Netherlands. PARTICIPANTS: Of 189 residents, 160 residents (84.7%) were screened for ESBL-E carriage. Of these 160 residents, 33 (20.6%) were ESBL-E positive. ESBL carriage rates varied substantially between wards (range, 0-47%). Four different ESBL-E clusters were observed. A bla CTX-M1-15 positive E. coli ST131 constituted the largest cluster (n=21) and was found in multiple wards (n=7). RESULTS: Our investigation revealed extensive clonal dissemination of bla CTX-M1-15-positive E. coli ST131 in a nursing home. Unexplained differences in ESBL prevalence were detected among the wards. CONCLUSIONS: As NHs constitute potential sources of multidrug-resistant bacteria, it is important to gain a better understanding of the risks factors and routes of transmission of ESBL-E

Extended-Spectrum-Beta-Lactamase Production in a Salmonella enterica Serotype Typhi Strain from the Philippines▿

A Salmonella enterica serotype Typhi strain was cultured from blood and fecal samples from a 54-year-old man with fever and diarrhea. He had returned from travel to the Philippines a few days earlier. Phenotypic and genotypic analysis confirmed the production of the SHV-12 extended-spectrum beta-lactamase