Tropical diarrhoea: new developments in traveller's diarrhoea

Prevalence, Antibiotic Susceptibility Profile, and Associated Risk Factors of Salmonella Isolate among Diarrheal Patients Visiting Dessie Referral Hospital, Northeast Ethiopia

Salmonellosis remains an important public health problem worldwide, particularly in the developing countries such as Ethiopia. A cross-sectional study was conducted to determine the prevalence, antibiotic susceptibility profile, and associated risk factors of Salmonella isolate among diarrheal patients who were visiting Dessie Referral Hospital, Dessie, Northeast Ethiopia, from November 2016 to January 2017. 384 stool samples were collected using sterile stool cups. Out of these, 20 (5.21%) were found to be positive for Salmonella species. The distribution of positive samples among the three age groups indicated that Salmonella species were predominantly prevalent in the age group of three months (0.25 years) to 4 years old patients. Abdominal pain, vomiting, watery consistency of stool, and 1–5 days of diarrhea were the clinical features that were significantly associated with salmonellosis. Eating raw vegetables and fruits, consumption of street-vended foods, cohabitation of animals, using water from the unprotected source, absence of latrine, and consumption of raw products of animals such as eggs and raw milk were the risk factors that were significantly associated with the prevalence of Salmonella species. The antibiotic sensitivity test was performed for the isolated Salmonella species against 5 currently recommended antibiotics. The antimicrobial sensitivity study carried out using the Kirby–Bauer disk diffusion method showed that 100% of Salmonella isolates were sensitive to ciprofloxacin and 80% sensitive to nalidixic acid, respectively. Among them, twenty isolated Salmonella species resistant to ampicillin, tetracycline, and trimethoprim-sulfamethoxazole were 100%, 85%, and 80%, respectively. This study revealed that Salmonella species were prevalent among diarrheal patients who were visiting Dessie Referral Hospital, and therefore, routine diagnosis of patients with diarrhea cases is required, and drugs must be prescribed after performing the sensitivity test, or checking the updated information on the local antibiotics pattern is always necessary.

Prevalence of Shigella species and its drug resistance pattern in Ethiopia: a systematic review and meta-analysis

Background

Shigella species are a major cause of dysentery and may attribute for death worldwide. Currently antibiotic resistance became the critical challenges for management of infectious disease. The aim was to conduct a systematic review and meta-analysis of Shigella species and its drug resistance pattern in Ethiopia.

Methods

A comprehensive literature search was conducted through internet searches using database of MEDLINE, PubMed, Google scholar, EMBASE, HINARI, Cochrane Library and reference lists of previous prevalence studies from January 1999 to November 2018. Results were presented in forest plot, tables and figures with 95% CI. The Cochrane Q test and I² test statistic were used to test heterogeneity across studies. The Pooled estimate of Shigella species and its drug resistance pattern was computed by a random effects model.

Results

The pooled prevalence of Shigella species in Ethiopia was 6.6% (95% CI 4.7–8.8). In the subgroup analysis, the highest prevalence was observed among patients in Health facility (8.5%, 95% CI 6.2–11.5) whereas the lowest prevalence was observed in Community based studies (1.6%, 95% CI 0.8–3.4). In addition, Shigella species were highly resistant to ampicillin, amoxicillin, erythromycin and multi-drug resistant (MDR) with the pooled resistance proportions of 83.1% (95% CI 75.7–88.6), 84.1% (95% CI 75.6–90.1), 86.5% (95% CI 70.9–94.4) and 83.2% (95% CI 77.1–87.9), respectively. On the other hand, comparably low resistance pattern was reported for ciprofloxacin 8.9% (95% CI 6.0–12.8), ceftriaxone 9.3% (95% CI 3.9–20.5), and norfloxacin 8.2% (95% CI 3.8–16.6) and gentamycin 17.3% (95% CI 11.2–25.9). Subgroup analyses indicated that study years were associated with a decreasing Shigella prevalence over time (p = 0.002).

Conclusion

The pooled estimate showed high burden of Shigella infection and its high proportion of drug resistance pattern to ampicillin, amoxicillin and erythromycin in Ethiopia. Therefore, initiating and scale up of performing drug susceptibility test for each shigellosis case, educate the community and health care providers on appropriate use of antibiotics need to be considered and strengthened.

Electronic supplementary material

The online version of this article (10.1186/s12941-019-0321-1) contains supplementary material, which is available to authorized users.

Vibrio Pathogens: A Public Health Concern in Rural Water Resources in Sub-Saharan Africa

Members of the Vibrio genus are autochthonous inhabitants of aquatic environments and play vital roles in sustaining the aquatic milieu. The genus comprises about 100 species, which are mostly of marine or freshwater origin, and their classification is frequently updated due to the continuous discovery of novel species. The main route of transmission of Vibrio pathogens to man is through drinking of contaminated water and consumption inadequately cooked aquatic food products. In sub-Saharan Africa and much of the developing world, some rural dwellers use freshwater resources such as rivers for domestic activities, bathing, and cultural and religious purposes. This review describes the impact of inadequately treated sewage effluents on the receiving freshwater resources and the associated risk to the rural dwellers that depends on the water. Vibrio infections remain a threat to public health. In the last decade, Vibrio disease outbreaks have created alertness on the personal, economic, and public health uncertainties associated with the impact of contaminated water in the aquatic environment of sub-Saharan Africa. In this review, we carried out an overview of Vibrio pathogens in rural water resources in Sub-Saharan Africa and the implication of Vibrio pathogens on public health. Continuous monitoring of Vibrio pathogens among environmental freshwater and treated effluents is expected to help reduce the risk associated with the early detection of sources of infection, and also aid our understanding of the natural ecology and evolution of Vibrio pathogens.

Prevalence and distribution of Cryptosporidium and Giardia in wastewater and the surface, drinking and ground waters in the Lower Rhine, Germany

Samples from different water sources (n = 396) were collected during 2009 and 2011. Wastewater (2-5 l) was purified by aluminium sulphate flocculation. Surface, ground and drinking waters (400-6400 l) were collected by filtration. Cryptosporidium oocysts and Giardia cysts were further concentrated by sucrose centrifugation. (Oo)cysts were identified by IFT (immunofluorescence test), DAPI (4',6-diamidino-2-phenylindole) staining and DICM (difference interference contrast microscopy). Out of 206 wastewater samples, 134 (65·0%) were found to be positive for Giardia cysts and 64 (31·1%) for Cryptosporidium oocysts. Parasite numbers ranged from 0 to 2436 cysts/l and 0 to 1745 oocysts/l. Eight (4·2%) surface and drinking water samples (n = 190) were found to be positive for Giardia cysts (0-56000/100 l), and 18 (9·5%) for Cryptosporidium oocysts (2400/100 l). The purpose of this study was to establish the prevalence and concentrations of Giardia lamblia and Cryptosporidium spp. by detecting (oo)cysts from water samples. This study provides substantial evidence that G. lamblia cysts and Cryptosporidium spp. oocysts are able to enter and circulate in the aquatic environment with negative implications for public health.

Bactericidal effects and mechanisms of visible light-responsive titanium dioxide photocatalysts on pathogenic bacteria

This review focuses on the antibacterial activities of visible light-responsive titanium dioxide (TiO(2)) photocatalysts. These photocatalysts have a range of applications including disinfection, air and water cleaning, deodorization, and pollution and environmental control. Titanium dioxide is a chemically stable and inert material, and can continuously exert antimicrobial effects when illuminated. The energy source could be solar light; therefore, TiO(2) photocatalysts are also useful in remote areas where electricity is insufficient. However, because of its large band gap for excitation, only biohazardous ultraviolet (UV) light irradiation can excite TiO(2), which limits its application in the living environment. To extend its application, impurity doping, through metal coating and controlled calcination, has successfully modified the substrates of TiO(2) to expand its absorption wavelengths to the visible light region. Previous studies have investigated the antibacterial abilities of visible light-responsive photocatalysts using the model bacteria Escherichia coli and human pathogens. The modified TiO(2) photocatalysts significantly reduced the numbers of surviving bacterial cells in response to visible light illumination. They also significantly reduced the activity of bacterial endospores; reducing their toxicity while retaining their germinating abilities. It is suggested that the photocatalytic killing mechanism initially damages the surfaces weak points of the bacterial cells, before totally breakage of the cell membranes. The internal bacterial components then leak from the cells through the damaged sites. Finally, the photocatalytic reaction oxidizes the cell debris. In summary, visible light-responsive TiO(2) photocatalysts are more convenient than the traditional UV light-responsive TiO(2) photocatalysts because they do not require harmful UV light irradiation to function. These photocatalysts, thus, provide a promising and feasible approach for disinfection of pathogenic bacteria; facilitating the prevention of infectious diseases.

Clinical and epidemiological characteristics of imported infectious diseases in Spanish travelers

INTRODUCTION

Spain could be a potential area in Europe for the development and spread of emerging diseases from the tropics due to its geoclimatic characteristics, but there is little information on infectious diseases imported by travelers. The aim of this article was to analyze clinical-epidemiological characteristics of infectious diseases imported by Spanish travelers from the tropics.

METHODS

A retrospective descriptive study of 2,982 travelers seeking medical advice who return ill from the tropics was conducted. Demographic data, details of travel (destination, type, and duration), preventive measures, clinical syndromes, and diagnoses were analyzed.

RESULTS

Nearly half (46.5%) the travelers had traveled to sub-Saharan Africa; 46.5% reported a stay exceeding 1 month (and almost a quarter more than 6 months). Following pre-travel advice, 69.1% received at least one vaccine and 35.5% took malarial chemoprophylaxis with variations according to geographical area of travel. In all, 58.8% of this took chemoprophylaxis correctly. Most common syndromes were fever 1,028 (34.5%), diarrhea 872 (29.3%), and cutaneous syndrome 684 (22.9%). Most frequent diagnoses were traveler's diarrhea (17.2%), malaria (17%), and intestinal parasites (10.4%). The three main syndromes in travelers to the Caribbean-Central America, Indian subcontinent-Southeast Asia, and other areas were diarrhea, fever, and cutaneous syndrome (p < 0.05); in sub-Saharan Africa were fever, cutaneous syndrome, and diarrhea (p < 0.05); and in South America were cutaneous syndrome, diarrhea, and fever (p < 0.05). Travelers to sub-Saharan Africa showed a higher frequency of malaria, rickettsiosis, filariasis, and schistosomiasis (p < 0.05); those to South America showed cutaneous larva migrants, other ectoparasitosis, and cutaneous/mucocutaneous leishmaniasis; and those to the Indian subcontinent-Southeast Asia showed intestinal parasitosis, arboviriasis, and enteric fever (p < 0.05).

CONCLUSIONS

Increased international travel is a key factor for the development and spread of emerging pathogens. Information on these diseases is essential to establish early warning mechanisms and action plans. Spain represents a unique setting for this.

Antibiotic susceptibility profiles of some Vibrio strains isolated from wastewater final effluents in a rural community of the Eastern Cape Province of South Africa

BACKGROUND

To evaluate the antibiogram and antibiotic resistance genes of some Vibrio strains isolated from wastewater final effluents in a rural community of South Africa. V. vulnificus (18), V. metschnikovii (3), V. fluvialis (19) and V. parahaemolyticus (12) strains were isolated from final effluents of a wastewater treatment plant (WWTP) located in a rural community of South Africa. The disk diffusion method was used for the characterization of the antibiogram of the isolates. Polymerase chain reaction (PCR) was employed to evaluate the presence of established antibiotic resistance genes using specific primer sets.

RESULTS

The Vibrio strains showed the typical multidrug-resistance phenotype of an SXT element. They were resistant to sulfamethoxazole (Sul), trimethoprim (Tmp), cotrimoxazole (Cot), chloramphenicol (Chl), streptomycin (Str), ampicillin (Amp), tetracycline (Tet) nalidixic acid (Nal), and gentamicin (Gen). The antibiotic resistance genes detected includes dfr18 and dfrA1 for trimethoprim; floR, tetA, strB, sul2 for chloramphenicol, tetracycline, streptomycin and sulfamethoxazole respectively. Some of these genes were only recently described from clinical isolates, demonstrating genetic exchange between clinical and environmental Vibrio species.

CONCLUSIONS

These results demonstrate that final effluents from wastewater treatment plants are potential reservoirs of various antibiotics resistance genes. Moreover, detection of resistance genes in Vibrio strains obtained from the wastewater final effluents suggests that these resistance determinants might be further disseminated in habitats downstream of the sewage plant, thus constituting a serious health risk to the communities reliant on the receiving waterbodies.

The effects of the bacterial interaction with visible-light responsive titania photocatalyst on the bactericidal performance

Bactericidal activity of traditional titanium dioxide (TiO₂) photocatalyst is effective only upon irradiation by ultraviolet light, which restricts the potential applications of TiO₂ for use in our living environments. Recently carbon-containing TiO₂ was found to be photoactive at visible-light illumination that affords the potential to overcome this problem; although, the bactericidal activity of these photocatalysts is relatively lower than conventional disinfectants. Evidenced from scanning electron microscopy and confocal Raman spectral mapping analysis, we found the interaction with bacteria was significantly enhanced in these anatase/rutile mixed-phase carbon-containing TiO₂. Bacteria-killing experiments indicate that a significantly higher proportion of all tested pathogens including Staphylococcus aureus, Shigella flexneri and Acinetobacter baumannii, were eliminated by the new nanoparticle with higher bacterial interaction property. These findings suggest the created materials with high bacterial interaction ability might be a useful strategy to improve the antimicrobial activity of visible-light-activated TiO₂.

Lack of an adverse effect of Giardia intestinalis infection on the health of Peruvian children

Giardia intestinalis is a common gastrointestinal protozoan worldwide, but its effects on childhood growth in developing countries are not clearly understood. The authors aimed to describe its effects on child growth. They followed 220 Peruvian children daily for diarrhea, weekly for stool samples, and monthly for anthropometry. The authors modeled the effect of nutritional status on the risk of Giardia infection and the risk of diarrhea attributable to Giardia using negative binomial regression. They modeled the effects of Giardia infection on growth using linear regression, with 85% of children becoming infected with Giardia and 87% of these becoming reinfected. In multivariable analysis, the risk of Giardia infection did not vary with weight for age (relative risk = 1.00, 95% confidence interval: 0.89, 1.12) or height for age (relative risk = 0.92, 95% confidence interval: 0.82, 1.04). Giardiasis did not affect growth at 1 or 2 months following the first infection at any age interval. The longitudinal prevalence of Giardia between 6 and 24 months of age was not associated with height gain in that interval (p = 0.981). Giardia was not associated with an increased risk of diarrhea at any age interval. Study results question the importance of Giardia as a childhood pathogen in developing countries where giardiasis is hyperendemic.

A report on a cluster of travelers' diarrhea among Cambodian students visiting Thailand

BACKGROUND

Travelers' diarrhea is an important gastrointestinal disorder in developing countries.

METHODS

A cluster of travelers' diarrhea among Cambodian students visiting Thailand is described in this article.

RESULTS

Nine cases of travelers' diarrhea were identified. These cases were among Cambodian students visiting Thailand under an exchange program. All presented with symptoms of diarrhea and nausea, and all improved within that day.

CONCLUSIONS

The prevention of gastrointestinal illness as well as recommendations for hygienic precautions for travelers who plan to visit tropical Asia, where the high prevalence of gastrointestinal disorder is documented, are important. In addition, a similar practice among local travelers within tropical Asia is also necessary.

Current perceptions of travelers' diarrhea treatments and vaccines: results from a postal questionnaire survey and physician interviews

BACKGROUND

Travelers' diarrhea (TD) occurs at high frequency in individuals from industrialized countries visiting destinations in nonindustrialized countries and may result in chronic complications such as Guillain-Barré syndrome.

METHODS

We distributed a questionnaire requesting information on physicians' perceptions of currently available TD products, hypothesized TD vaccines, and aspects of travelers' behavior. Some physicians also were interviewed by telephone.

RESULTS

We obtained completed questionnaires from named individuals at 68 UK/US clinics. These individuals reported seeing a total of approximately 76,500 travelers per year, and estimated that 61% (UK) and 77% (US) of travelers present 2 weeks or more predeparture. More US (92%) than UK (43%) travelers are advised to purchase TD products. In both countries, 85% of travelers would be prescribed an ideal TD vaccine, but only approximately 47% (UK) and approximately 65% (US) would purchase this vaccine. About 80% of physicians would recommend an hypothesized 100% effective Campylobacter vaccine for travelers visiting regions where 30% of TD cases are caused by Campylobacter.

CONCLUSIONS

Physicians support the concept of TD vaccines, including campylobacteriosis vaccines. An ideal TD vaccine might be purchased by up to 16% (UK) and 28% (US) of relevant travelers. A 100% effective Campylobacter vaccine might be purchased by over 2 million UK/US travelers per year.

Visible-light-induced bactericidal activity of a nitrogen-doped titanium photocatalyst against human pathogens

The antibacterial activity of photocatalytic titanium dioxide (TiO(2)) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO(2) substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO(2) substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO(2) and carbon-doped TiO(2) substrates. We also found that protein- and light-absorbing contaminants partially reduce the bactericidal activity of nitrogen-doped TiO(2) substrates due to their light-shielding effects. In the pathogen-killing experiment, a significantly higher proportion of all tested pathogens, including Shigella flexneri, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Streptococcus pyogenes, and Acinetobacter baumannii, were killed by visible-light-illuminated nitrogen-doped TiO(2) substrates than by pure TiO(2) substrates. These findings suggest that nitrogen-doped TiO(2) has potential application in the development of alternative disinfectants for environmental and medical usages.

Diarrhea and respiratory symptoms among travelers to Asia, Africa, and South and Central America from Scotland

Surveillance using admissions to hospital, while being useful, is a poor indicator of the real incidence of disease encountered by travelers. An alternative is self-reported illness among those who attended at a pretravel clinic prior to their travels. Estimates of incidence and risk factors were determined for attendees at a travel clinic in Scotland using a questionnaire. Analysis for risk factors was carried out for those travelers visiting countries in Africa, Asia, or South and Central America, who had traveled for 1 week or more and had returned between 1997 and 2001 (N= 4,856). Multivariate logistic regression was used to test the hypotheses that time abroad and age-group would be significant for both respiratory and diarrheal symptoms regardless of which of the three geographical areas are visited. From 2006 returned questionnaires (response rate = 41.3%), diarrhea and respiratory symptoms were reported by 44.2 and 16.8% of respondents, respectively; the incidence was significantly greater among travelers to Asia for both diarrheal (55.5%) and respiratory (23.7%) symptoms than among travelers to Africa (36.6 and 12.2%, respectively) or South and Central America (39.5 and 16.2%, respectively). For diarrhea, age was a highly significant risk factor for travelers to Asia, South and Central America, and Africa. Being a self-organized tourist/backpacker, traveling to Asia was associated with increased risk, while for Africa and South and Central America visiting family or friends was associated with a lower risk. For travelers to Asia, traveling to the Indian subcontinent was significantly associated with increased risk. The majority of travelers had an adverse event while traveling abroad, with diarrhea and respiratory conditions being especially common despite attending a travel clinic for advice prior to departure. However, the limitations of this surveillance-based strategy have highlighted the requirement for more research to understand more fully the issues of risk and incidence among travelers to high-risk destinations from Scotland.

Traveler's diarrhea

Travelers' diarrhea is common. Between 8% and 50% of travelers develop diarrhea; incidence depends on the country visited. The attack rate is highest for travelers from a developed country who visit a developing country. Children are at particular risk. Travelers' diarrhea is usually acquired through ingestion of fecally contaminated food and water. Most cases are due to a bacterial pathogen, commonly, Escherichia coli, and occur within the first few days after arrival in a foreign country. More than 90% of episodes develop within the first 2 wk of initiation of travel. Dehydration is the most common complication. Water and electrolyte replenishment is important and can usually be accomplished with an oral rehydration solution. Judicious use of an antimotility agent and antimicrobial therapy reduces the duration and severity of diarrhea. Pretravel education on hygiene and on the safe selection of food items is important in minimizing episodes. Dukoraltrade mark (Aventis Pharma Ltd., Auckland, New Zealand) vaccine should be considered for travelers who are 2 y of age or older and who will be visiting an area associated with risk of infection due to enterotoxigenic E coli or Vibrio cholerae. Typhoid vaccine is recommended for travelers who will be visiting areas with poor sanitation and hygiene.

Quinine sulfate inhibits invasion of Salmonella typhimurium and Shigella flexneri: a preliminary study

BACKGROUND

The incidence of typhoid fever and shigellosis parallels that of malaria, so many individuals who are on antimalarial drugs can be found in areas where these diseases are widespread. We investigated the effect of quinine sulfate on the growth and invasion of Salmonella typhimurium and Shigella flexneri M90T to determine whether people on antimalarials can have secondary gain from some protection against typhoid fever and shigellosis.

METHODS

The effect of 50 and 100 microM quinine sulfate on the invasive ability of Salmonella typhimurium and Shigella flexneri M90T into human colon adenocarcinoma-2 (Caco-2) cells was studied during the infection period. The invasive efficiency was expressed as the number of viable internalized bacteria by counting the colony-forming units.

RESULTS

The invasive ability of Salmonella typhimurium and Shigella flexneri M90T was significantly inhibited by 50 and 100 microM quinine sulfate in a dose-dependent manner (for Salmonella typhimurium) when the drug was added to Caco-2 cell monolayers during the infection period.

CONCLUSIONS

Since so many people who are on antimalarial drugs visit and inhabit areas that are endemic to typhoid fever and Shigella infection, a study on the influence of these drugs on the disease is long overdue. Our data indicate that quinine sulfate interferes with the invasion and internalization of Salmonella typhimurium and Shigella flexneri M90T into host cells. Further studies on additional strains/serotypes with other newer antimalarials at various concentrations are needed to verify this effect of quinine sulfate and to draw conclusions on its significance in vivo.

Kinetics and strain variation of phagosome proteins of Entamoeba histolytica by proteomic analysis

The protozoan parasite Entamoeba histolytica ingests and feeds on microorganisms and mammalian cells. Phagocytosis is essential for cell growth and implicated in pathogenesis of E. histolytica. We report here the dynamic changes of phagosome proteins during phagosome maturation by proteomic analysis using reversed-phase capillary liquid chromatography and ion trap tandem mass spectrometry. Phagosomes were isolated at various intervals after internalization of latex beads. Immunoblot analysis and electron microscopy verified successful isolation of phagosomes. A total of 159 proteins were identified from the reference strain HM1 at different stages of phagosome maturation. Approximately 70% of them were detected in a time-dependent fashion, suggesting dynamism of phagosome biogenesis. The kinetics of representative proteins were verified by immunoblots and also by video microscopy of live transgenic amebae expressing green fluorescent protein-fused EhRab7A. Furthermore, we observed significant differences in phagosome profiles between HM1 and two recent clinical isolates. Approximately 60% of 229 proteins detected in at least one of these three strains were identified only in one strain, while approximately 20% of these proteins were detected in all three strains. These data should provide significant insights into molecular characterization of phagosome biogenesis, and help to elucidate the pathogenesis of this important infection.

Pathophysiology and impact of enteric bacterial and protozoal infections: new approaches to therapy

Despite numerous scientific advances in the past few years regarding the pathogenesis, diagnostic tools and treatment of infectious enteritis, enteric infections remain a serious threat to health worldwide. With globalization of the food supply, the increase in travel, mass food processing and antibiotic resistance, infectious diarrhea has become a critical concern for both developing and developed countries. Oral rehydration therapy has been cited as the most important medical discovery of the century due to the millions of lives that have been saved. However, statistics concerning diarrhea-induced mortality and the highly underestimated morbidity continue to demonstrate the severity of the problem. A more complete understanding of the pathogenesis of infectious diarrhea and potential new vaccines and effective treatments are badly needed. In addition, public health preventive actions, such as early detection of outbreaks, care with food, water and sanitation and, where relevant, immunization, should be considered a priority. This article provides an overview of the epidemiological impact, pathogenesis and new approaches to the management of enteric infections.

Mechanism of resistance to several antimicrobial agents in Salmonella Clinical isolates causing traveler's diarrhea

The evolution of antimicrobial resistance in Salmonella isolates causing traveler's diarrhea (TD) and their mechanisms of resistance to several antimicrobial agents were analyzed. From 1995 to 2002, a total of 62 Salmonella strains were isolated from stools of patients with TD. The antimicrobial susceptibility to 12 antibiotics was determined, and the molecular mechanisms of resistance to several of them were detected as well. The highest levels of resistance were found against tetracycline and ampicillin (21 and 19%, respectively), followed by resistance to nalidixic acid (16%), which was mainly detected from 2000 onward. Molecular mechanisms of resistance were analyzed in 16 isolates. In these isolates, which were resistant to ampicillin, two genes encoding beta-lactamases were detected: oxa-1 (one isolate) and tem-like (seven isolates [in one strain concomitantly with a carb-2]). Resistance to tetracycline was mainly related to tetA (five cases) and to tetB and tetG (one case each). Resistance to chloramphenicol was related to the presence of the floR and cmlA genes and to chloramphenicol acetyltransferase activity in one case each. Different genes encoding dihydrofolate-reductases (dfrA1, dfrA12, dfrA14, and dfrA17) were detected in trimethoprim-resistant isolates. Resistance to nalidixic acid was related to the presence of mutations in the amino acid codons 83 or 87 of the gyrA gene. Further surveillance of the Salmonella spp. causing TD is needed to detect trends in their resistance to antimicrobial agents, as we have shown in our study with nalidixic acid. Moreover, such studies will lead to better treatment and strategies to prevent and limit their spread.

Probiotics for mother and child

For the survival of humankind, nothing can be as important as the health of a mother and a child. As the world's population grows to more than 6 billion, it might seem ridiculous to suggest that any real threat exists to the human species. Diseases have long ravaged populations, as have wars, poverty, and malnutrition. Life today is no different with new and emerging diseases such as SARS and Mad Cow Disease leaving a trail of concern around the planet. All that being said, the AIDS crisis is threatening humans like no other. In countries such as Botswana, close to half the population of pregnant women is infected. Of great concern, the disease is now prevalent among women and teenage girls, threatening not only their lives but those of their offspring. Efforts to control this spread are quite abysmal, albeit well intentioned. Likewise, the death of a child every 15 seconds from diarrheal disease is not being addressed with the same vigor as SARS, even though the risk of dying from the latter for most people is similar to being struck by lightning. In the end, it is the economy and politics that dictate health spending. Image and perception are everything. While deaths mount among women and children from AIDS and other infections, the potential to intervene with a low-risk natural concept of probiotics seemed all too distant. As evidence mounts of the attributes of certain probiotic strains to treat diarrhea and reduce the risk of urogenital and other diseases, the developing world has failed to embrace it, support its evaluation and implementation, and take it to where it is needed the most. In this review, the case for and against probiotics for urogenital and intestinal infections is presented based on current literature. The story is far from complete, but the potential for improving the health of the mother and child is significant. United Nations and World Health Organization guidelines have now been developed to vanquish the unproved marketing hype products that have given probiotics a bad name. It is now up to science to deliver the remedies, and to society to make sure that only proven products reach the marketplace and the people in most need.

Emerging Causes of Traveler's Diarrhea: Cryptosporidium, Cyclospora, Isospora, and Microsporidia

Travel is a risk factor for acquiring infection with a spore-forming protozoa: Cryptosopridium, Cyclospora, Microsporidia, and Isospora. Certain travel destinations have a high disease burden and intense exposure. Patients present with persistent diarrhea and a history of recent travel to a developing country in the tropics. Very mild infections may be underdiagnosed and may cause typical traveler's diarrhea. In a patient with a history of travel and persistent diarrhea unresponsive to the usual antibiotic and antidiarrhea treatment, stool studies for all four of these protozoa infections should be performed. If immune status is normal and the disease is mild, symptomatic therapy may suffice. Effective treatment is available for Cyclospora, Microsporidia, and Isospora.