- Volume 55, Issue 5, 2006

Sepsis is responsible for significant morbidity and mortality in patients suffering from severe burn injuries. Burn patients are known to be immunocompromised, and it is generally accepted that the immunosuppressed patient may experience human cytomegalovirus (HCMV) infection and disease. Review of the very limited available literature identifies a seroconversion rate of between 18 and 22 % for burn patients who were seronegative for HCMV prior to suffering their burn injury. Furthermore, approximately 50 % of HCMV antibody-positive patients may reactivate. Blood products and allografted skin have clinically been identified as possible sources of HCMV transmission in burn patients. Experience in the treatment of infection or disease in burn patients is very scarce and limited to immunoglobulin therapy. Animal experiments have demonstrated that murine cytomegalovirus (MCMV)-seropositive skin grafts are able to infect immunodeficient mice as well as burned mice. Murine studies have also demonstrated that infection with MCMV enhances susceptibility to secondary bacterial infection and increases mortality in these animals. Burned mice challenged with MCMV have a significantly higher level of bacterial translocation to mesenteric lymph nodes than either control thermally injured mice without MCMV inoculation or non-burned mice injected with MCMV alone. In summary, it remains controversial whether HCMV infection per se alters outcome for the majority of burn patients. Subgroups of severely burned, seronegative patients may benefit from blood products and skin from seronegative donors. Antiviral strategies are not yet evaluated for the burn patient. Further investigations utilizing modern diagnostic techniques seem necessary.

The crystalline biofilms formed by Proteus mirabilis can seriously complicate the care of patients undergoing long-term bladder catheterization. The generation of alkaline urine by the bacterial urease causes calcium and magnesium phosphates to precipitate from urine and accumulate in the catheter biofilm, blocking the flow of urine from the bladder. The pH at which these salts crystallize from a urine sample, the nucleation pH (pHn), can be elevated by diluting the urine and by increasing its citrate content. The aim of this study was to examine whether manipulation of pHn in these ways modulated the rate at which crystalline biofilm developed. Experiments in laboratory models of the catheterized bladder infected with P. mirabilis showed that when the bladder was supplied with a concentrated urine (pHn 6·7) at a low fluid output (720 ml per 24 h), catheters blocked at 19–31 h. Diluting this urine 1 : 4 increased the pHn to 7·5 and models supplied with this urine at 2880 ml per 24 h took 110–137 h to block. When models were supplied with urine containing citrate at 1·5 mg ml−1 or above (pHn 8·3–9·1), the catheters drained freely for the full 7 day experimental period. Scanning electron microscopy revealed that the catheter biofilms that developed in urine with high pHn values were devoid of crystalline formations. These observations should encourage a clinical trial to examine the effect of increasing a patient's fluid intake with citrate-containing drinks on the encrustation and blockage of catheters.

Brucellosis remains a major zoonosis worldwide; therefore, better understanding of its immunology is a priority for the development of new therapeutic and vaccination strategies. Genetic factors appear to have an important role in the pathogenesis of infectious diseases such as brucellosis. Adhesion molecules, such as members of the selectin family, participate in the interaction between leukocytes and the endothelium, as well as in inflammatory cell recruitment. The impact of L-selectin polymorphisms on brucellosis has not so far been investigated. The aim of this study was to assess an L-selectin Phe206Leu (F206L) polymorphism in patients with active brucellosis, and to analyse its possible relationship with disease progression. A case-control association study was carried out on 619 subjects, including 374 patients with brucellosis and 245 age- and sex-matched healthy controls. Genomic DNA was isolated, and amplification of L-selectin genomic regions was performed by PCR incorporating sequence-specific primers (PCR-SSP) to distinguish the genotypes. The frequencies of the F206L polymorphism were studied. A significant difference in F206L polymorphism was found between patients with brucellosis and controls. The 206Leu allele was more frequent in patients than in healthy individuals (36·6 versus 28 %, P=0·003). In addition, there was an association between the presence of the 206Leu allele and a relapse of brucellosis (odds ratio 6·53, 95 % confidence interval 1·5–28·8, P=0·005). The higher frequency of L-selectin genotypes in patients with brucellosis than in control individuals, as well as the association between the 206Leu allele and the occurrence of brucellosis relapse, suggest that the F206L polymorphism could make individuals more vulnerable to brucellosis.

In the study, group B streptococci (GBS) isolated from bovines and humans in and around Van, eastern Turkey, were serotyped, and their haemagglutination and lectin-agglutination properties were also determined. This study is the first epidemiological survey of GBS serotypes performed in Turkey. A total of 148 GBS isolates, 76 from bovine milk and 72 from women attending a maternity polyclinic, were examined by co-agglutination, slide haemagglutination and slide lectin-agglutination tests. By the co-agglutination test, 34 (44·7 %) of bovine isolates and 49 (68 %) of human isolates could be serotyped. In bovine isolates, type VII (11·8 %), III (10·5 %), Ic (6·5 %) and VIII (3·9 %) were the most frequently detected serotypes. The most frequent human serotypes were Ic (33·3 %), IV (8·3 %), VIII (6·9 %), V (5·5 %) and R (5·5 %). In the haemagglutination test using rabbit erythrocytes, 23 (33·3 %) bovine and 15 (23·4 %) human isolates were found to be positive. The bovine GBS isolates showed a significant positive agglutination reaction with Dolichos biflorus lectin (30·4 %), whereas the human GBS isolates were found to be positive for Arachis hypogea (18·8 %) and Canavalia ensiformis (37·5 %) lectins. The treatment of GBS with trypsin was also found to be important for the demonstration of the haemagglutination and lectin-agglutination properties of GBS. The results of the study provide data on serotype distribution and the formulation of a possible GBS vaccine in Turkey, and the lectin-agglutination tests may also be useful for differentiating bovine and human GBS strains.

A comprehensive investigation of invasive Streptococcus pneumoniae was carried out in Brazil as part of the programme of the national epidemiological surveillance system. The investigation provided data on the trends of resistance to antimicrobial agents. A total of 6470 isolates of S. pneumoniae collected in the country from 1993 to 2004 were tested. During this period of time, the number of penicillin-resistant strains rose from 10·2 to 27·9 %. The proportions of intermediate and high-level resistant strains in 1993, which were 9·1 and 1·1 %, respectively, rose to 22·0 and 5·9 % in 2004. Geometric mean MICs for penicillin increased after the year 2000, to 0·19 μg ml−1 in 2004; most of these isolates were from patients with pneumonia and from children under 5 years old, and belonged to serotype 14. There was a significant increase in the number of isolates belonging to serotypes included in the 7-valent conjugate vaccine from children under 5 years old: from 48·6 % in 1993 to 69·6 % in 2004, mainly related to an increase in the frequency of serotype 14 isolates. From 2000 to 2004, meningitis isolates showed higher resistance rates to cefotaxime (2·6 %) compared to non-meningitis isolates (0·7 %); percentages of isolates resistant to trimethoprim-sulfamethoxazole, tetracycline, erythromycin, chloramphenicol and rifampicin were 65, 14·6, 6·2, 1·3 and 0·7 %, respectively. No levoflaxin resistance was observed. Multidrug resistance was identified in 4·6 % of isolates, of which 3·8 % were resistant to three classes, 0·7 % to four classes and 0·1 % to five classes of antimicrobial agent. The study provides valuable information that may support empirical antimicrobial therapy for severe S. pneumoniae infections in Brazil, and emphasizes the need for conjugate pneumococcal vaccination.

A total of 133 clinical strains of Vibrio cholerae comprising 44 strains of O1, 45 strains of O139 and 44 strains of non-O1, non-O139 serogroups isolated from hospitalized patients in Kolkata, India, from 1992 to 2000 was examined for the presence of class 1, 2 and 4 integrons. By PCR and DNA sequencing, seven strains of O1, one strain of O139 and six strains of non-O1, non-O139 serogroups were found to contain class 1 integron-harbouring genes aadA1, aadA2 (encoding resistance to streptomycin and spectinomycin), blaP1 (resistance to β-lactams), aar-3 (resistance to rifampicin), aacA4 (resistance to kanamycin and gentamicin), and dfrA1 and dfrA15 (resistance to trimethoprim). Most strains produced one or two bands using primers specific for the amplification of the variable region where the antibiotic-resistance genes are located, and their sizes ranged from 700 to 1250 bp. However, one strain of V. cholerae O1 isolated in 1994 gave a 2483 bp fragment, the largest fragment so far found in a class 1 integron of V. cholerae O1. No strain was positive for the intI2 gene. All V. cholerae strains, regardless of serogroup, were positive for the intI4 gene by PCR and using a colony hybridization test. Amplification of the intI4 gene by PCR yielded a 2200 bp fragment (1260 bp larger than the expected size) from three V. cholerae O139 strains isolated in 1999. Sequence analysis of this amplicon revealed an insertion of IS1359 in the middle of the intI4 gene. These data indicate that a class 1 integron is present in some clinical strains of V. cholerae isolated in Kolkata, India, and that a class 4 integron is ubiquitously distributed among V. cholerae strains regardless of serogroup.

Although the high prevalence of blood-borne viral infections and syphilis in correctional facilities has been well documented globally, such data are sparse from Africa, and there has been no such data from Ghana. This study sought to estimate the prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis among prison inmates and officers at prisons in Nsawan and Accra, Ghana. Prisoners and officers in 3 of the 46 prisons in Ghana were surveyed from May 2004 to May 2005. Subjects voluntarily completed a risk-factor questionnaire and provided blood specimens for unlinked anonymous testing for the presence of antibodies to HIV, HCV and Treponema pallidum, the causative agent of syphilis, and the surface antigen of hepatitis B virus (HBsAg). Almost 16 % (3770) of the total of 23 980 prison inmates in Ghana were eligible, and 281 (7·5 %) of those eligible took part, whilst almost 23 % (1120) of the total of 4910 prison officers were eligible, and 82 (7·3 %) of those eligible took part. For the 281 inmates tested, HIV seroprevalence was 19·2 %, 17·4 % had HBsAg, HCV seroprevalence was 19·2 % and reactive syphilis serology was noted in 11 %. For the 82 officers tested, HIV seroprevalence was 8·5 %, 3·7 % had HBsAg, HCV seroprevalence was 23·2 % and reactive syphilis serology was noted in 4·9 %. The data indicate a higher prevalence of HIV and HCV in correctional facilities (both prison inmates and officers) than in the general population in Ghana, suggesting their probable transmission in prisons in Ghana through intravenous drug use, unsafe sexual behaviour and tattooing as pertains to prisons worldwide.

Duodenitis-proximal jejunitis (DPJ) is an idiopathic condition in the horse characterized by inflammation and oedema of the duodenum and proximal jejunum. Clinical signs include colic, ileus, depression, fluid accumulation in the small intestine and stomach, and endotoxaemia. The objective of this study was to investigate prospectively the role of Clostridium difficile in this idiopathic disease. Nasogastric reflux from 10 consecutive cases with DPJ and 16 consecutive horses with other causes of nasogastric reflux was cultured for C. difficile, other Clostridium spp., and Salmonella. Toxigenic strains of C. difficile were isolated from 10/10 (100 %) of horses with DPJ and 1/16 controls (P<0·0001). No other known pathogenic clostridia were isolated from either group. Results of this study suggest that C. difficile might be an important cause of this syndrome.

Bacterial invasion of host epithelial cells plays an important role in the pathogenesis of periodontal diseases; however, the interactions between subgingival species and the gingival crevice cells are not fully understood. This study determined the prevalence of a group of oral bacterial species on or in epithelial cells derived from periodontal pockets and the gingival crevice of subjects with periodontitis. Samples of epithelial cells were obtained from 120 sites with periodontal pockets ⩾4 mm and 92 periodontally healthy sites from 49 patients (mean age 46·3±1·4 years; 43 % males) with chronic periodontitis. Bacteria in or on epithelial cells were separated from unattached bacteria by Percoll density-gradient centrifugation. The presence and levels of 33 oral species were determined in epithelial cell samples by whole genomic DNA probes and the checkerboard method. The most frequently detected species were Porphyromonas gingivalis (42 %), Treponema denticola (38 %), Prevotella intermedia (37 %), Streptococcus intermedius (36 %), Campylobacter rectus (35 %), Streptococcus sanguinis (35 %) and Streptococcus oralis (34 %). Species of Actinomyces were found in low prevalence and levels. The data indicated that there were more micro-organisms on or in epithelial cells obtained from periodontal pockets than from healthy sulci; however, no significant differences regarding the percentage and level of any specific species were found between these sites. Veillonella parvula, S. oralis, Streptococcus gordonii and Streptococcus mitis tended to be more prevalent in sites without disease. These findings demonstrated that a wide range of oral species may be detected on or in crevicular epithelial cells from sites with periodontitis and from periodontally healthy sulci.