Opportunistic testing for urogenital infection with Chlamydia trachomatis in south-western Switzerland, 2012: a feasibility study

The feasibility of opportunistic screening of urogenital infections with Chlamydia trachomatis was assessed in a cross-sectional study in 2012, in two cantons of south-western Switzerland: Vaud and Valais. Sexually active persons younger than 30 years, not tested for C. trachomatis in the last three months, were invited for free C. trachomatis testing by PCR in urine or self-applied vaginal swabs. Of 2,461 consenting participants, 1,899 (77%) were women and all but six (0.3%) submitted a sample. Forty-seven per cent of female and 25% of male participants were younger than 20 years. Overall, 134 (5.5%) of 2,455 tested participants had a positive result and were followed up. Seven per cent of all candidates for screening were not invited, 10% of invited candidates were not eligible, 15% of the eligible candidates declined participation, 5% of tested participants testing positive were not treated, 29% of those treated were not retested after six months and 9% of those retested were positive for C. trachomatis. Opportunistic C. trachomatis testing proved technically feasible and acceptable, at least if free of charge. Men and peripheral rural regions were more difficult to reach. Efforts to increase testing and decrease dropout at all stages of the screening procedure are necessary.

[Chlamydia: from population screening to individual repeated screening]

Chlamydia trachomatis is a frequent sexually transmitted infection especially in young adults and adolescents. Its complications can impair a woman's reproductive potential. chlamydia control has several challenges. These include asymptomatic infections; a long duration of untreated infections; re-infections and partner treatments. Any person with infection is at high risk of re-infection. Repeated screening would decrease, at an individual level, the risk of complications. General practitioners, gynaecologists and centres for sexual health could participate in Chlamydia screening for asymptomatic infections, in Switzerland, the cost of the laboratory test is fixed by national tariff regulations. The cost is high and prohibitive for many, especially adolescents and young adults and needs to be lowered.

[Role of probiotics in the treatment and prevention of antibiotics-associated diarrhea]

Probiotics constitute an alternative to prevent or treat antibiotics-associated diarrhea (AAD). According to WHO, probiotics are "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". Recent meta-analyses, including adult and pediatric in- and outpatients, outlined the lack of good quality studies and of the lack of evaluation of side-effects. These meta-analyses showed a positive effect of probiotics in AAD, nevertheless without identifying patients who would benefit the most of them. Severe side-effects have been described in immunocompromised patients, those with abnormalities in their intestinal barrier, and those with central venous catheters.

[The changing epidemiology of sexually transmitted infections in Switzerland]

Sexually transmitted infections (STI), such as syphilis, gonorrhoea and infections caused by Chlamydia have been increasingly reported in Switzerland during the last decade. After having consistently decreased since the early 90s, reports of HIV infections were on the rise from 2000 to 2008. STIs are thus far from being controlled in Switzerland and their epidemiology has become more complex: different STIs circulate in different populations. The national program for HIV and STI 2011-2017 (PVNI) takes this challenge up and covers now the prevention, screening and treatment of all STIs. Primary care physicians, gynaecologists and specialists have an important role to play in provider initiated testing and counselling (PICT) and in the treatment of STIs.

[Tick-borne encephalitis: first autochtonous case and epidemiological surveillance in canton Valais, Switzerland]

Tick-borne encephalitis (TBE, in French MEVE) is a viral disease usually transmitted to man through an infected tick belonging to the genus Ixodes. Every year about 135 cases of TBE are reported to the Swiss Federal Office of Public Health. Emerging in north-east of Switzerland in the seventies, endemic areas have been slowly spreading. Actually 18 cantons out of 26 have been reached. In the western part of Switzerland, spared until not long ago, new endemic foci are spreading toward the lake of Geneva and recently in Valais. The precise exposure history of human cases, as well as the evaluation of collected tick samples allow the detection of endemic foci which are discontinuous and of variable size. New and more efficient methods are needed to monitor the changing epidemiology of TBE.

Investigation of classical epidemiological links between patients harbouring identical, non-predominant meticillin-resistant Staphylococcus aureus genotypes and lessons for epidemiological tracking

According to molecular epidemiology theory, two isolates belong to the same chain of transmission if they are similar according to a highly discriminatory molecular typing method. This has been demonstrated in outbreaks, but is rarely studied in endemic situations. Person-to-person transmission cannot be established when isolates of meticillin-resistant Staphylococcus aureus (MRSA) belong to endemically predominant genotypes. By contrast, isolates of infrequent genotypes might be more suitable for epidemiological tracking. The objective of the present study was to determine, in newly identified patients harbouring non-predominant MRSA genotypes, whether putative epidemiological links inferred from molecular typing could replace classical epidemiology in the context of a regional surveillance programme. MRSA genotypes were defined using double-locus sequence typing (DLST) combining clfB and spa genes. A total of 1,268 non-repetitive MRSA isolates recovered between 2005 and 2006 in Western Switzerland were typed: 897 isolates (71%) belonged to four predominant genotypes, 231 (18%) to 55 non-predominant genotypes, and 140 (11%) were unique. Obvious epidemiological links were found in only 106/231 (46%) patients carrying isolates with non-predominant genotypes suggesting that molecular surveillance identified twice as many clusters as those that may have been suspected with classical epidemiological links. However, not all of these molecular clusters represented person-to-person transmission. Thus, molecular typing cannot replace classical epidemiology but is complementary. A prospective surveillance of MRSA genotypes could help to target epidemiological tracking in order to recognise new risk factors in hospital and community settings, or emergence of new epidemic clones.

[Septic arthritis]

Septic or acute bacterial arthritis is a medical emergency. The primary physician must suspect this condition even when clinical symptoms are non specific or with simultaneous inflammatory arthropathy. Septic arthritis can have serious complications. Optimal care requires hospital admission in general. Synovial fluid aspiration and its correct interpretation, the appropriate choice and timely administration of empiric antibiotic therapy can limit destruction of the joint's cartilage. The adaptation of the antibiotic regimen after reception of microbiological results and the adequate treatment in full length require interdisciplinary collaboration between the hospital physician, including the specialist in infectious diseases, the microbiology laboratory and post-hospital care.

[Urinary tract infection: a tailored diagnosis]

Urine dipstick testing reveals the presence of esterase secreted by leukocytes, and nitrites produced by some bacteria. The presence of either one confirms the diagnosis of acute uncomplicated urinary tract infection, that is in a woman of childbearing age with typical symptoms. Indeed, false positive tests are rare in this population. In contrast, dipstick testing is much less reliable in aged patients, and those with incontinence or an urinary catheter. Because asymptomatic bacteriuria is frequent in this population which, on the other hand, suffers more often from urinary tract infections due to bacteria that don't produce nitrites, the specificity and sensitivity of dipstick testing are low and should motivate a comprehensive approach to avoid unnecessary treatments or missed diagnoses.

[Diagnosis and treatment of urethritis]

Clinical urethritis should motivate urine analyses including tests for leukocytes and PCR for C. trachomatis and N. gononhocae. The culture of an urethral swab for gonococci is sensitive as well. It allows susceptibility tests. Other infectious agents have been associated with urethritis (e.g., M. genitalium, T. vaginalis, H. simplex). They should be searched in case of negative first results or non-response to an empiric treatment. Given the emergence of resistances to quinolones, single doses of azithromycin 1 g plus cefixime 400 mg constitute a good choice which permits to ensure adherence. Contact tracing, screening for other sexually transmitted infections, and the evaluation of the sexual behaviour should always be done in order to prevent any further transmission.

Cefepime versus imipenem-cilastatin for treatment of nosocomial pneumonia in intensive care unit patients: a multicenter, evaluator-blind, prospective, randomized study

In a randomized, evaluator-blind, multicenter trial, we compared cefepime (2 g three times a day) with imipenem-cilastatin (500 mg four times a day) for the treatment of nosocomial pneumonia in 281 intensive care unit patients from 13 centers in six European countries. Of 209 patients eligible for per-protocol analysis of efficacy, favorable clinical responses were achieved in 76 of 108 (70%) patients treated with cefepime and 75 of 101 (74%) patients treated with imipenem-cilastatin. The 95% confidence interval (CI) for the difference between these response rates (-16 to 8%) failed to exclude the predefined lower limit for noninferiority of -15%. In addition, therapy of pneumonia caused by an organism producing an extended-spectrum beta-lactamase (ESBL) failed in 4 of 13 patients in the cefepime group but in none of 10 patients in the imipenem group. However, the clinical efficacies of both treatments appeared to be similar in a secondary intent-to-treat analysis (95% CI for difference, -9 to 14%) and a multivariate analysis (95% CI for odds ratio, 0.47 to 1.75). Furthermore, the all-cause 30-day mortality rates were 28 of 108 (26%) patients in the cefepime group and 19 of 101 (19%) patients in the imipenem group (P = 0.25). Rates of documented or presumed microbiological eradication of the causative organism were similar with cefepime (61%) and imipenem-cilastatin (54%) (95% CI, -23 to 8%). Primary or secondary resistance of Pseudomonas aeruginosa was detected in 19% of the patients treated with cefepime and 44% of the patients treated with imipenem-cilastatin (P = 0.05). Adverse events were reported in 71 of 138 (51%) and 62 of 141 (44%) patients eligible for safety analysis in the cefepime and imipenem groups, respectively (P = 0.23). Although the primary end point for this study does not exclude the possibility that cefepime was inferior to imipenem, some secondary analyses showed that the two regimens had comparable clinical and microbiological efficacies. Cefepime appeared to be less active against organisms producing an ESBL, but primary and secondary resistance to imipenem was more common for P. aeruginosa. Selection of a single agent for therapy of nosocomial pneumonia should be guided by local resistance patterns.

Polymorphism of HIV type 1 gag p7/p1 and p1/p6 cleavage sites: clinical significance and implications for resistance to protease inhibitors

Amino acid substitutions at HIV-1 Gag p7/p1 and p1/p6 cleavage sites may be selected under antiretroviral pressure or represent natural polymorphisms. Whether changes are associated with specific protease (PR) mutation patterns and different clinical evolution has not been investigated. p7/p1 and p1/p6 cleavage site sequences from sera from 110 patients infected with HIV-1 were compared by regression analysis, using clinical, laboratory, and sequence variables, and the evolution of CD4(+) cell counts and viral load over time. Sixteen of 35 (46%) individuals naive to PR inhibitors (PIs), and 49 of 75 (65%) receiving PI-containing regimens had a p7/p1 and/or p1/p6 cleavage site polymorphism (p = 0.06). A431V and/or L449F were present exclusively among individuals failing PI treatment (17 of 75 [23%] and 3 of 75 [3%], respectively). There was a significant association between A431V and PR M46I,L (OR 13.7; 95% CI 4.2-44.3) and V82A,F,T (OR 8.8; 95% CI 2.7-27.8). Natural polymorphism P453L was strongly associated with the selection of PR I84V (OR 49.5; 95% CI 12-212) and selected against V82 mutation (OR 0.15; 95% CI 0.02-1. 2). After a median followup of 15 months, no polymorphism was associated with parameters of disease progression among individuals failing treatment. Only a limited set of amino acid substitutions can be tolerated at p7/p1 and p1/p6 cleavage sites. A431V is selected in association with specific PR inhibitor mutations. Natural polymorphism P453L might direct the PR resistance pathway through I84V instead of V82 mutation. No short-term clinical impact of cleavage site substitutions was documented.

HIV epidemiology and treatment - 1999

Potent antiretroviral treatment has led to a dramatic decrease in HIV-associated morbidity and mortality. This paper reviews (1) current recommendations for the initiation of antiretroviral therapy, (2) the natural history of HIV infection after initiation of treatment, and (3) toxicity and resistance issues.

Changes in renal function associated with indinavir

BACKGROUND

Indinavir use is associated with a spectrum of renal and urinary tract complications including nephrolithiasis, renal colic and pain without recognizable lithiasis, and a picture of crystalluria-dysuria. A frank nephropathy has not been recognized as part of the spectrum.

METHODS

A retrospective analysis of 106 HIV-infected individuals receiving indinavir was performed with the purpose of identifying the frequency and risk factors for indinavir-associated nephropathy and urinary complications. Individuals receiving ritonavir or nelfinavir served as controls.

RESULTS

A sustained elevation of creatinine (>20%, into abnormal range) was identified in 20 (18.6%) subjects treated with indinavir but not with other protease inhibitors. Creatinine elevation was associated with treatment duration of more than 54 weeks [odds ratio (OR), 7.1; 95% confidence interval (CI), 1.8-27.7], low baseline body mass index < or = 20 kg/m2 (OR, 4.0; 95% CI, 1.0-16.6), and use of trimethoprim-sulphamethoxazole (TMP-SMX; OR, 4.6; 95% CI, 1.5-13.8). Lower urinary specific gravity (P = 0.015), and leukocyturia (P<0.001) were frequently associated features of indinavir nephropathy. No patient developed severe renal impairment and abnormalities were reversible upon discontinuation of the drug. Complications (renal colic, or pain and dysuria) occurred after a mean of 36 weeks (95% CI, 23-48) of indinavir treatment in 13 subjects (12.3%), eight of whom (62%) presented elevated creatinine during follow-up. Only long-term exposure to TMP-SMX (>160 weeks) was identified as a potential risk for the occurrence of a clinical event (OR, 4.7; 95% CI, 1.2-19.2).

CONCLUSIONS

A crystal nephropathy, characterized by serum creatinine elevation, loss of concentrating ability of the kidney, leukocyturia, and renal parenchymal image abnormalities, is a frequent complication of indinavir therapy. Identification of individuals at risk, particularly those with low body mass index or receiving TMP-SMX prophylaxis, may help the decision to initiate indinavir or chose an alternative protease inhibitor in order to minimize renal and urinary tract adverse events.

Age-stratified seroprevalence of measles, mumps and rubella (MMR) virus infections in Switzerland after the introduction of MMR mass vaccination

We have performed age-stratified seroprevalence studies for MMR to evaluate these vaccinations. Serum samples submitted for diagnostic testing were randomly selected for unlinked anonymous panels. IgG antibodies were tested by ELISA and indirect immunofluorescence. In the vaccination cohort (age 1.5 to 6.5 years), seroprevalence attained 80%. For measles and mumps it continued to increase to 95%, while for rubella it declined transiently to 60% between 7 and 12 years of age. We observed no differences according to gender in any age group in 1991-1992. (Semi)quantitative values of the IgG antibodies against all three viruses increased during adolescence, suggesting wild virus circulation. In 1992, MMR vaccination has reached < 80% of the children during their second year of age. Due to previous monovalent measles and mumps vaccinations in pre-school children and due to endemic and epidemic activity, particularly of mumps virus, a trough of the seroprevalence in adolescents was evident only for rubella. MMR vaccination campaigns performed at school since 1987 have increase seroprevalence in this population segment and have probably over-compensated for the expected shift to the right of the seroprevalence curves. A more compulsive implementation of the recommended childhood vaccination schedule and continued efforts at catchup vaccinations during school age especially for rubella are necessary to avoid the accumulation of susceptible young adults during the forthcoming decades.

The incidence of rubella virus infections in Switzerland after the introduction of the MMR mass vaccination programme

We have collected data on the incidence of rubella in Switzerland from 1987 to 1992 to help evaluating the impact of the measles, mumps and rubella (MMR) mass vaccination programme which started in 1985 in this country. We used detailed informations on samples submitted for diagnostic testing in conjunction with anonymous laboratory notifications to the Swiss Federal Office for Public Health, and data from the Swiss sentinel network of general practitioners to find trends in the incidence of rubella after the introduction of mass vaccination. We observed an unabated seasonal oscillation without decreasing trend during the observation period and were unable to detect a shift in the age distribution of cases. An important proportion of laboratory-confirmed rubella occurred in women of childbearing age. Immigrants from regions with low endemicity of rubella were at increased risk of contracting rubella and transmitting it to their offspring. We conclude, that MMR mass vaccination has not interrupted the circulation of rubella virus in Switzerland, and that improvements in the implementation and surveillance of the MMR vaccination campaign are necessary in order to avoid untoward effects of it.

Rapid identification of mycobacteria to the species level by polymerase chain reaction and restriction enzyme analysis

A method for the rapid identification of mycobacteria to the species level was developed on the basis of evaluation by the polymerase chain reaction (PCR) of the gene encoding for the 65-kDa protein. The method involves restriction enzyme analysis of PCR products obtained with primers common to all mycobacteria. Using two restriction enzymes, BstEII and HaeIII, medically relevant and other frequent laboratory isolates were differentiated to the species or subspecies level by PCR-restriction enzyme pattern analysis. PCR-restriction enzyme pattern analysis was performed on isolates (n = 330) from solid and fluid culture media, including BACTEC, or from frozen and lyophilized stocks. The procedure does not involve hybridization steps or the use of radioactivity and can be completed within 1 working day.