Rat strains differ in susceptibility to maternal and fetal infection with Mycoplasma pulmonis

PROBLEM: Vaginally infected Sprague-Dawley (SD) rats are more susceptible to adverse pregnancy outcomes than Wistar (WIS) rats. We postulated that SD rats have enhanced hematogenous spread of Mycoplasma pulmonis to fetal tissues. METHOD OF STUDY: WIS and SD dams were infected intravenously with 10(7), 10(6), and 10(5) colony-forming units of M. pulmonis at gestation day 14. Dams and six randomly selected fetuses were cultured at days 15, 16, 17, and 18 of gestation. RESULTS: In the high-dose group, 100% of fetuses were colonized regardless of rat strain. Significantly higher numbers of M. pulmonis were isolated from placenta (low dose, P < 0.0001; medium dose, P < 0.024; high dose, P < 0.0001), amniotic fluid (low dose, P < 0.003; medium dose, P < 0.017), and fetuses (low dose, P < 0.0011) of SD rats. Spread of M. pulmonis to the amniotic fluid and fetus occurred 1 day earlier in SD rats. CONCLUSIONS: The difference in susceptibility between the two rat strains cannot be explained by hematogenous spread alone. The relative resistance to adverse pregnancy outcomes in WIS rats may be a function of a more robust innate immune system. These rat strains may represent an animal model to address host resistance factors to intrauterine infection.     

Ureaplasma urealyticum serotypes in urinary tract disease.

Ureaplasma urealyticum cultures from 124 patients with urinary tract disease were serotyped by indirect immunofluorescence, using antisera to serotypes I to VIII. A similar range of serotypes was recovered from first-voided, midstream, and bladder-aspiration (SPA) urine, upper urinary tract samples, and vaginal swabs. Serotype VI was predominant (44/124) among the samples, whereas serotypes V (1/124 samples) and VII (0/124 samples) were uncommon. Twenty of 124 cultures contained more than one serotype, and three cultures were untypeable. Serotypes cultured from bladder urine were also present in vaginal and urethral samples, although these samples often carried additional serotypes. Consecutive SPA samples from the same patient invariably contained the same serotype, whereas some consecutive midstream urine samples showed a loss or gain of serotypes with time. One patient carried the same serotype in SPA urine over a period of 13 months. The pattern of serotypes recovered from the urinary tract was similar irrespective of the sampling site, the site of infection, the clinical diagnosis and renal function of the patient, and the presence or absence of other microorganisms. Colonization above the urethra and association with urinary tract disease appeared to be serotype independent.     

Incidence of aerobactin-positiveEscherichia coli strains in patients with symptomatic urinary tract infection

A total of 323Escherichia coli strains from children with primary acute non-obstructive pyelonephritis (n=144) or cystitis (n=56) and from adults with acute non-obstructive pyelonephritis (n=66) or cystitis (n=57) were examined for presence of the aerobactin-mediated iron uptake system and expression of P-fimbriae. Overall, pyelonephritogenicEscherichia coli strains were significantly more often aerobactin-positive (72 %) than cystitis strains (42 %) (p<0.001). Seventy-three percent of the isolates from children with acute pyelonephritis were aerobactin-positive compared to 54 % of the cystitis strains (p<0.05). PyelonephritogenicEscherichia coli strains from adults were also significantly more often aerobactin-positive (70 %) than cystitis strains (30 %) (p<0.001). The cystitis strains from children were more often aerobactin-positive than cystitis strains from adult patients (p<0.05). There was a significant correlation between presence of the aerobactin-mediated iron uptake system and expression of P-fimbriae in all strains (p<0.001).     

Responses to vaccination in strains of mice that differ in susceptibility to coccidiosis.

BALB/c mice are normally resistant to infection with Eimeria vermiformis than C57BL/6 (B6) mice, but these phenotypes were reversed by prior vaccination with crude antigens prepared from developmental stages of the parasite: B6 mice were protected, and BALB/c mice were made more susceptible. Infections with a heterologous species, E. pragensis, were unaffected when this was given either alone or together with E. vermiformis. In both strains of mice, vaccination induced serum antibody responses to E. vermiformis and the levels were boosted by superimposed infection, the highest values being found in BALB/c mice. Cellular responses in the mesenteric lymph nodes (MLN), as indicated by cellularity and proliferation, either unstimulated or restimulated in vitro with E. vermiformis antigen, were decreased in both strains, but markedly more in BALB/c than B6. The capacity of MLN cells to transfer immunity to naive recipients was lowered by vaccination of BALB/c donors but unimpaired in vaccinated B6 mice. Responses to the mitogen, concanavalin A, and to unrelated antigens (human erythrocytes and fowl gamma globulin) were unaffected. Thus, parenteral vaccination, which increased the susceptibility of BALB/c mice to infection with E. vermiformis, had a depressing effect on some specific immune responses in the MLN. It was surprising to find some reduction in the cellular responses of the MLN of B6 mice also, although they were protected by vaccination.     

Non-fermenters in urinary tract infection

Sixty four (4.4%) strains of non-fermenting gram negative bacteria (NFGNB) were isolated out of 1,380 bacterial isolates from 7,784 urine samples, of which 43 were isolated from male patients and 21 from female patients. P. aeruginosa was found to be the commonest (67.2%) followed by A. lwoffi (7.8%), A. anitratus and P. acidovorans testosterani (6.2% each), P. maltophilia and P. denitrificans (4.8% each), P. putida and P. vesiculare (1.5% each). Forty two(65.6%) of these isolates were isolated as pure cultures and 22(34.4%) as predominant organisms. Most of these isolates i.e. 50-88.8% were sensitive to Norfloxacin and Ofloxacin and 22.2% to 66.6% of these isolates were sensitive to Gentamycin and Cephalexin whereas 11.1% of these isolates were sensitive to Co-trimoxazole and Ampicillin. All of these isolates were resistant to Penicillin and Tetracycline.     

Oral vaccination against coccidiosis: responses in strains of mice that differ in susceptibility to infection with Eimeria vermiformis.

Four strains of mice with different susceptibilities to Eimeria vermiformis were orally dosed with a crude antigen prepared from sporulated oocysts of the parasite, with or without cholera toxin as adjuvant. The effect on subsequent challenge infections depended on the resistance and susceptibility phenotypes of the host: oocyst production was reduced in susceptible C57BL/6 and NIH mice but increased in resistant BALB/c and C3H mice. Despite this contrast, no fundamental differences were detected between the immune responses of BALB/c and C57BL/6 mice, either to vaccination or after superimposed infection, but the suppressing and enhancing effects of vaccination were transmissible to naive recipients via suspensions of mesenteric lymph node cells. The results obtained are compared with those previously reported for parenterally immunized BALB/c and C57BL/6 mice.     

Evaluation of levofloxacin susceptibility against strains isolated from lower urinary tract infections in the community

The aim of this study was to evaluate the in vitro activity of levofloxacin (LVX) in comparison to nalidixic acid (NAL), ofloxacin (OFX), norfloxacin (NOR), amoxicillin (AMX), cefixime (CFM), cotrimoxazole (SXT) and nitrofurantoin (FT), against 402 strains recently isolated from urine specimens in outpatient women suffering from lower urinary tract infections for which short-term treatment was not indicated. MICs were determined by the agar dilution method on Mueller-Hinton medium (Bio-Rad) according to the recommendations of the Comite de l'Antibiogramme de la Societe Francaise de Microbiologie (CA-SFM). Strains were classified as susceptible (S), intermediate (I) or resistant (R) according to the CA-SFM recommended breakpoints. Quality control was carried out using three reference strains: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853. For E. coli, the most prevalent species (345 isolates: 85.3%), susceptibilities were as follows: AMX: 60.6%, CFM: 99.1%, NAL: 94.8%, NOR: 97.4%, OFX: 97.4%, LVX: 97.4%, SXT: 84.5%, FT: 98%. This study confirms the good in vitro activity of LVX, OFX, and CFM against strains isolated from urinary tract infections in the community and particularly against E. coli, which is by far the most prevalent pathogen, 90% of strains, with more than 97% of strains being susceptible.     

Inbred mouse strains differ in resistance to lethal Coccidioides immitis infection.

Inbred strains of mice were infected intraperitoneally with Coccidioides immitis, and the mean lethal dose was determined after 28 days. DBA/2N mice had a mean lethal dose of greater than 10(5) arthroconidia, whereas BALB/cAnN, C57BL/6N, and C57L/J mice had a mean lethal dose of less than or equal to 10(3). Since both BALB/c and DBA/2 mice are the H-2d haplotype, resistance is not primarily determined by the major histocompatibility locus. Resistance was the dominant phenotype. The pattern of C. immitis-resistant strains does not correspond to the strain distribution of the lsh gene or to the pattern of resistance to Blastomyces dermatitidis or Cryptococcus neoformans. Both resistant and susceptible mice, however, could be successfully immunized with a killed spherule vaccine, and susceptible BALB/cAnN mice were protected from an otherwise lethal infection by prior immunization with an attenuated mutant of C. immitis. Despite the evidence that BALB/cAnN mice could respond to immunization, nonimmune mice did not control the later phase of intraabdominal infection as well as DBA/2N mice. Dissemination of C. immitis to the lung occurred frequently in BALB/cAnN but not in DBA/2N mice. This suggests that BALB/cAnN mice cannot mount an effective immune response to C. immitis during the course of infection.     

Trimethoprim-sulphamethoxazole in urinary tract infection due to Streptococcus faecalis

In-vitro sensitivities were performed on 140 specimens of urine which grew Streptococcus faecalis of more than 100 000 organisms/ml between March 1970 and February 1971. Although the combination of trimethoprim and sulphamethoxazole definitely appeared to be more effective than sulphonamide alone and as effective as ampicillin, its use for more than two weeks in 14 cases of uncomplicated urinary tract infection due to Streptococcus faecalis led to development of resistance. As in these cases organisms were resistant to sulphonamide to start with, it is suggested that the combination should be used in prolonged treatment only where the organisms are sensitive to both the individual antibiotics. Ampicillin is still the drug of choice in urinary tract infection due to Streptococcus faecalis. The alternative appears to be rotational therapy with other potent antibiotics.     

超敏C反应蛋白和尿路感染信息在尿路感染诊断中的应用

目的探讨超敏C反应蛋白（hs-CRP）及尿路感染信息（UTI-Info）对尿路感染（UTI）的诊断价值。方法对380例疑似UTI患者的尿标本进行尿培养,用UF-1000i全自动尿液有形成分分析仪测定白细胞数（WBC）及细菌数（BACT）,得到UTI-Info;用AU2700全自动生化分析仪测定静脉血hs-CRP含量;以细菌定量培养结果为标准对照,评估hs-CRP、UTI-Info、hs-CRP＋UTI-Info诊断UTI的灵敏度、特异性、诊断符合率等。结果除污染标本外,余下360份标本中,细菌培养结果阳性有102份,阳性率为28.3%。以细菌培养为参考方法,hs-CRP诊断UTI的灵敏度、特异性、诊断符合率分别为85.3%、70.9%、75.0%;UTI-Info诊断UTI的灵敏度、特异性、诊断符合率分别为76.5%、84.5%、82.2%;hs-CRP＋UTI-Info诊断UTI的灵敏度、特异性、诊断符合率分别为70.6%、97.3%、89.7%。结论 hs-CRP联合UTI-Info能快速诊断UTI并能提高特异性及诊断的准确性。     

Cranberries and lower urinary tract infection prevention

Lower urinary tract infections are very common diseases. Recurrent urinary tract infections remain challenging to treat because the main treatment option is long-term antibiotic prophylaxis; however, this poses a risk for the emergence of bacterial resistance. Some options to avoid this risk are available, including the use of cranberry products. This article reviews the key methods in using cranberries as a preventive measure for lower urinary tract infections, including in vitro studies and clinical trials.     

Aspergillus infection in urinary tract post-ureteric stenting

Fungal infections of the urinary tract are usually encountered following prolonged antibiotic use, instrumentation and indwelling urinary catheters. These type of infections are mostly seen in immuno-compromised patients. Candida is the most common among the fungal infections of urinary tract followed by Aspergillus infection. Here is a case report of a 26 year old diabetic female who presented with abdominal pain, fever, nausea and vomiting. She had undergone double-J stenting 15-20 days back. The cause of the symptoms was not detected till the patient underwent C.T Scan-KUB with excretory urography which showed the displaced D-J stent. Then on performing replacement of D-J stent, cystoscopy was done and the tissue sample was sent for microbiological and histopathological examination. On Microbiological examination, Aspergillus flavus was isolated from the tissue, which was culprit behind the disease. Patient was then treated with anti-fungal drugs, following which she gradually improved.     

Pseudomonas urinary tract infection in mice.

When Pseudomonas aeruginosa was injected through a catheter into the bladder. Hemorrhage, edema, and vessel engorgement were seen 1 h after challenge. At 3 hours we observed microulceration of the bladder, which rapidly healed and was rarely present after 24 h. Pseudomonas was cultured from 50% of the kidneys at 1 week, and the number of kidneys infected decreased over 4 weeks.     

Saturation-inhibition index as a measure of the risk of calcium oxalate stone formation in the urinary tract.

Studies were carried out on multiple urine samples from eight patients with recurrent idiopathic calcium oxalate stone formation and eight normal persons to define an index of the risk of forming calcium oxalate stones. Under the same conditions of dietary and fluid intake the urine samples of the patients with stone formation were more supersaturated with calcium oxalate (P less than 0.001) and had lower concentrations of protective inhibitors of crystallization (P less than 0.001) than those of the controls. However, the best separation between the groups was defined by a discriminant line relating inhibitory activity and urine saturation. A measure of the risk of forming large crystals, the saturation-inhibition index, was defined as the distance of each urine from the discriminant line. The patients with stone formation had a significantly higher mean saturation-inhibition index than the controls (P less than 0.001). Both the percentage of large calcium oxalate crystals excreted (P less than 0.001) and the stone episode rate (P less than 0.005) were significantly correlated with the saturation-inhibition index.     

Serum resistance of Escherichia coli strains causing urinary tract infection and diarrhoea in relation to alpha haemolysin production and O type

A total of 46 alpha-hemolytic and 40 non-hemolytic clinical isolates of Escherichia coli were collected from pediatric patients with urinary tract infection and diarrhoea. Of 39 (84.7%) alpha-hemolytic strains and 27 (67.5%) non-hemolytic strains were resistant to 10% serum and there was no significant difference between urinary and stool isolates. On the contrary when 100% serum was used, 22 (47.8%) of the alpha-hemolytic and 7 (17.5%) of the non-hemolytic strains were resistant (p<0.01). and significantly greater resistance was found in urinary tract infection than from the stool samples (47% versus 24%, p<0.01). Serum resistance was higher in serogroups O6, O18 and O75. Production of alpha-hemolysin was more frequent in serogrops O2, O6, O8, O18 and O75. Thus, the resistance to human serum can determine clinical significance of Escherichia coli from different sources and alpha-hemolysin contributes to the virulence of Escherichia coli in initiation and perpetuation of clinical infection.     

Biofilm formation among methicillin-resistant Staphylococcus aureus isolates from patients with urinary tract infection

Staphylococci have been confirmed to form biofilms on various biomaterials. The purpose of this study was to investigate biofilm formation among methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients with urinary tract infection (UTI) and to assess the relationship between biofilm-forming capacities and virulence determinants/clinical background. Over a 12-year period from 1990 through 2001, a total of 109 MRSA isolates were collected from patients (one isolate per patient) with UTI at the urology ward of Okayama University Hospital. We used the in vitro microtiter plate assay to quantify biofilm formation. We then investigated the presence of several virulence determinants by polymerase chain reaction assay and found eight determinants (tst, sec, hla, hlb, fnbA, clfA, icaA, and agrII) to be predominant among these isolates. Enhanced biofilm formation was confirmed in hla-, hlb-, and fnbA-positive MRSA isolates, both individually and in combination. Upon review of the associated medical records, we concluded that the biofilm-forming capacities of MRSA isolates from catheter-related cases were significantly greater than those from catheter-unrelated cases. The percentage of hla-, hlb-, and fnbA-positive isolates was higher among MRSA isolates from catheter-related cases than those from catheter-unrelated cases. Our studies suggest that MRSA colonization and infection of the urinary tract may be promoted by hla, hlb, and fnbA gene products.