2385 cases were included: 55.3% among MSM, 31.3% among MSW and 13.3% among females; cases among MSM increased from 55.8% in 2006 to 62.9% in 2010 while no trends were found among the other two groups.
In addition to the countrywide surveillance system, beginning in January 2006, a sentinel surveillance project was started in a network of clinics specialising in STI, the EPI-ITS Network. The project objective was to collect detailed clinical and epidemiological data, including HIV co-infection, in all gonorrhoea and syphilis cases diagnosed in the EPI-ITS Network. Yearly reports as well as a paper with results from this project have been published previously [7, 8].
The objectives of this paper are: a) to describe the characteristics of gonorrhoea cases diagnosed in a network of 15 clinics from 2006 to 2010; b) to analyse differences among cases who were MSM, men who have sex exclusively with women (MSW) and women, respectively; and c) to investigate factors associated with HIV co-infection.
Cases diagnosed in the network represented 25.7% of the total number of gonorrhoea cases notified to the population surveillance system in Spain during the study period (27.2% in 2006, 22.6% in 2007, 24.5% in 2008, 29.7% in 2009 and 24.7% in 2010). In addition to STI clinics, gonorrhoea cases in Spain can be diagnosed in a variety of settings, including primary care centres, gynaecological and dermatological clinics, and those providing family planning services, both in the public and private sector.
From 2006 to 2010, a total of 2385 gonorrhoea cases were identified in the participating centres. Of these, 1320 (55.3%) occurred among MSM, 747 (31.3%) among MSW and 318 (13.3%) among heterosexual females; twenty cases with missing information, either on gender or on gender of their sexual partners, were excluded from the analysis.
Gonorrhoea cases diagnosed in 15 STI clinics in Spain from 2006 to 2010, by year of diagnosis, sex and transmission route. *MSW: Men who have sex exclusively with women; MSM: Men who have sex with men.
Gonorrhoea cases diagnosed in 15 STI clinics in Spain from 2006 to 2010. Concurrent diagnosis of specific STI by sex and transmission route. *MSW: Men who have sex exclusively with women; MSM: Men who have sex with men.
Information on HIV status was available for a total of 2150 gonorrhoea cases (90.3% of MSM, 87.4% of MSW and 95.9% of heterosexual females). HIV co-infection was highest among MSM (20.9%) followed by MSW (2.3%) (Table 1). A significant increasing trend in gonorrhoea/HIV co-infection was found among MSM (from 15.9% in 2006 to 27.8% in 2010). In the multivariate analysis factors associated with co-infection were: age older than 35 years, low educational level, origin in Western Europe or Latin-America, being MSM, history of STI, having a concurrent STI, and reporting an HIV infected partner as the source of gonorrhoea infection. On the contrary, women were less likely to be infected with HIV (Table 2).
This study has limitations. Variables such as educational level and probable source of infection have a substantial proportion of missing data. Furthermore, cases are not representative of all gonorrhoea cases in Spain, therefore the results can only be extrapolated to the setting from which the cases arose and not to the whole Spanish population. However, to our knowledge, most of the STI clinics operating in Spain belong to this network and cases included in this study represent more than one fourth of all gonorrhoea cases declared in Spain from 2006 to 2008.
Although bacteria dominate the GI tract ecosystem, species from the archaeal domain can also be found in the GI tract, with the methanogens, Methanobrevibacter smithii and Methanosphaera stadtmanae being by far the most dominant archaeal groups (Gill et al. 2006; Mihajlovski et al. 2008). While it was previously assumed that these methanogens were only present in a minor fraction of healthy subjects, application of new DNA isolation methods has led to the observation that they are in fact highly prevalent (Dridi et al. 2009; Salonen et al. 2010b). In addition to bacteria and archaea, eukaryotic microorganisms can also be members of the intestinal microbiota. Culture-independent analysis of the fungal diversity in the GI tract has demonstrated that the majority of the phylotypes belonged to the two fungal phyla Ascomycota (which includes the genera Candida and Saccharomyces) and Basidiomycota (Ott et al. 2008; Scanlan and Marchesi 2008).
In addition to the variation in microbial composition along the GI tract, the microbiota present in the intestinal lumen also differs significantly from that attached to and imbedded in the intestinal mucus layer. Since mucosa-associated microorganisms live in close contact with host cells, it is likely they execute different functions within the GI ecosystem compared with luminal microorganisms. Several studies have reported a significant difference in dominant microbial community composition between colonic biopsies and faecal samples in humans (Eckburg et al. 2005; Lepage et al. 2005; Zoetendal et al. 2002). It should be kept in mind, however, that in these studies colonic biopsies were obtained from humans undergoing standard colonoscopy, which in general is preceded by a laxative preparation in order to clean the GI tract. The influence of this procedure on the luminal and mucosa-associated microbiota is still largely unknown (Mai et al. 2006).
Due to the application of culture-independent molecular approaches, our knowledge of the intestinal microbiota has been advanced significantly (Zoetendal et al. 2006). Yet, a complete description of the microbial diversity along the human GI tract cannot be given at this moment. Future research should include more samples from the various distinct niches along the GI tract, which nowadays can be collected using minimally invasive methods and which can be deeply analysed using high-throughput technologies.
A main focus of current research is to understand the functional contribution of the human intestinal microbiota to the host. Function-driven metagenomics is a first step in assessing the functional capacity of the intestinal microbiota. A prediction of the functional capacity can originate from the metagenome by comparing the assembled sequences to reference databases, such as the COG (clusters of orthologous groups) and KEGG (Kyoto encyclopedia of genes and genomes) databases. Moreover, function-driven metagenomics can be applied to assign a function to predicted gene products and can even contribute to gene discovery (Tasse et al. 2010; Cowan et al. 2005). The first metagenomic studies have demonstrated that, compared with the human genome, the human intestinal microbiome is highly enriched for COG and KEGG categories involved in metabolism (Gill et al. 2006; Kurokawa et al. 2007; Turnbaugh et al. 2009). Pathways involved in metabolism of energy, amino acids, nucleotides, carbohydrates, cofactors and vitamins, terpenoids and polyketides, and the biosynthesis of secondary metabolites are highly represented in the human microbiome. These pathways not only allow the microbes to generate energy, to grow and proliferate, but also to influence the host. Some of the metabolites are being taken away from the host while other ones are provided (e.g. SCFA, vitamins, gases). Overall, the (metabolic) interaction between microbes and host is beneficial for both parties. Future studies should provide data to further establish and detail the functional contribution of the intestinal microbiota to the metabolic capacity of the host.
It is widely accepted that microbial colonisation of the GI tract starts during and directly after birth when neonates are exposed to bacteria that are derived from the mother and the surrounding environment (Adlerberth and Wold 2009; Mackie et al. 1999). Yet, the human foetal environment is not completely microbiologically sterile and there are indications that non-pathological in utero exposure of the foetus to intestinal bacteria or bacterial DNA frequently occurs (Pettker et al. 2007; Satokari et al. 2009). In addition, the isolation of bacteria from the meconium (the first stool of the neonate), umbilical cord blood and amniotic fluid of healthy neonates has been reported (Jiménez et al. 2005, 2008). Postnatal colonisation of the GI tract is highly variable amongst neonates and is influenced by several factors including mode of delivery, type of infant feeding, gestational age, infant hospitalisation and antibiotic use (Penders et al. 2006). It is, however, still unclear how each of these factors exactly influences the infant microbial diversity and how this is related to health. A disturbed development of the infant microbiota has been associated with the development of disease later in life (Vael and Desager 2009). For example, associations have been made between dysbiosis in infants and the later development of childhood obesity (Collado et al. 2008b; Kalliomäki et al. 2008) and atopic and allergic diseases (Björkstén et al. 2001; Kalliomäki et al. 2001; Penders et al. 2007; Sjögren et al. 2009; Wang et al. 2008).
Several culture-independent studies have shown that there is a large inter-individual variability amongst infants in the development of the microbiota (Favier et al. 2002; Palmer et al. 2007; Penders et al. 2006; Roger et al. 2010). In addition, it has been demonstrated that the infant microbiota is highly dynamic and develops in a step-wise fashion with an increase in diversity over time (Palmer et al. 2007; Roger et al. 2010). An important stage in the colonisation of the GI tract of infants is the period in which the infants feed on the milk they receive either by breastfeeding or by infant-formula feeding. During this period, the faecal microbiota of infants consists mainly of bifidobacteria (Roger and McCartney 2010; Roger et al. 2010). Some bifidobacteria are highly adapted to the digestion of the oligosaccharides present in human milk (Zivkovic et al. 2010). The infant intestinal microbiota contains a relatively low diversity in Bifidobacterium populations; B. breve, B. bifidum and B. longum subsp. infantis are the most common Bifidobacterium species (Roger et al. 2010). Compared with breast-fed infants, the intestinal microbiota of formula-fed infants is characterised by less diverse Bifidobacterium populations (Roger et al. 2010) and more complex communities of Clostridia, Enterobacteriaceae, Bacteroides and Enterococcus (Harmsen et al. 2000; Penders et al. 2006). The introduction of solid food (weaning) marks an increase in microbial diversity and changes in the microbial composition towards an adult microbiota (Koenig et al. 2010). For example, dominant Bifidobacterium populations change; B. adolescentis, B. catenulatum and B. longum subsp. longum are more abundantly present in the adult microbiota (Matsuki et al. 2004). The successive shifts of different microbial communities within the first years of life ultimately result in the development of an adult-like microbiota. 2b1af7f3a8