Neglect of skin wounds and the risk of becoming a Staphylococcus aureus nasal carrier: a cohort study.

BACKGROUND: Nasal carriers of Staphylococcus aureus have an increased risk of acquiring skin and soft tissue infections, which could manifest as outbreaks, especially in crowded settings. Current prevention programs are ineffective, antibiotic resistance is rising and risk factors for becoming a carrier are incompletely understood. We aimed to examine whether a behavior, the neglect of skin wounds, is a risk factor for becoming a Staphylococcus aureus carrier during training. METHODS: We conducted a field-based cohort study among male infantry trainees in three seasons in Israel during 2011-12. Participants underwent anterior nares cultures and answered structured questionnaires on potential risk factors on two occasions: before and 3 weeks after start of training (N = 542). Attitudes and practices toward neglect of skin wounds were defined as perseverance in training at all costs, despite having a wound. Samples were processed within 18 hours for identification of Staphylococcus aureus. Univariable and multivariable logistic regression analyses were performed to assess risk factors for becoming a carrier. RESULTS: Carriage prevalence increased by 43.3% during training, from 33.2% to 47.6% (p < 0.01). One-fourth (25.4%) of those with a negative culture before training became carriers. None of the socio-demographic characteristics was a risk factor for becoming a carrier while the risk was lower in the winter (Odds ratio [OR] = 0.42; 95% confidence interval [CI]: 0.23-0.78, p < 0.01) and spring (OR = 0.46; 0.26-0.81, p < 0.01) seasons compared to the summer season. Neglect of skin wounds in practice and attitude was a risk factor for becoming a carrier (OR = 2.40; 1.13-5.12, p = 0.02), as well as neglect in practice or attitude (OR = 1.86; 1.04-3.34, p = 0.04) compared to no neglect when controlled for season. The preventable fraction in the population attributed to neglect of skin wounds was 33%. CONCLUSIONS: Neglect of skin wounds is an independent, common and strong risk factor for becoming a Staphylococcus aureus carrier during training. This preventable behavior should not be ignored and should be addressed in public health programs during training and in other settings. Further research on behavioral determinants of Staphylococcus aureus carriage and infection is warranted.

Phenotypic characteristics of enterotoxigenic Escherichia coli associated with acute diarrhea among Israeli young adults.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea among infants and children in developing countries, as well as among travelers to these areas. The major virulence factors of ETEC are the colonization factor antigens (CFAs) and a heat-labile enterotoxin (LT) and/or a heat-stable enterotoxin (ST). Among Israeli recruits serving under military field conditions, 107 of all examined isolates expressed LT or ST, and CFAs could be characterized in 68% of the isolates, in which CFAs of the CFA/II group and CS6 were the most prevalent. Additionally, 31% of the 107 ETEC isolates showed resistance to three or more of the antimicrobial agents examined, and the percentage of resistant isolates expressing LT was significantly higher than those expressing ST or LT+ST. These results may be important for development of an effective vaccine and for facilitation of an empirical choice of antibiotic treatment or prophylaxis for traveler's diarrhea in this area.

A cluster of ecthyma outbreaks caused by a single clone of invasive and highly infective Streptococcus pyogenes.

BACKGROUND: Ecthyma is an invasive, ulcerated skin infection. Four ecthyma outbreaks occurred in different infantry units in the Israeli Defense Force from October 2004 through February 2005. Morbidity attack rates in the first 3 outbreaks were 89% (49 of 55 soldiers), 73% (32 of 44), and 82% (37 of 45). In the fourth outbreak, in which early intervention (antimicrobial treatment and improvement of hygiene) was applied, the attack rate was 25% (10 of 40 soldiers). In the first outbreak cluster, 4 soldiers experienced poststreptococcal glomerulonephritis, and 5 cases of systemic sequelae were recorded (1 case of severe septic shock, 3 cases of pneumonia, and 1 case of septic olecranon bursitis). METHODS: Streptococcus pyogenes and Staphylococcus aureus were isolated from ecthyma sores, oropharynx, and anterior nares of affected and unaffected soldiers involved in all 4 outbreaks. RESULTS: Although the S. aureus isolates had different genomic profiles, >90% of S. pyogenes isolates were identified as belonging to a single clone, emm type 81, T type 8. Epidemiological investigation revealed that the hygiene levels of the soldiers and their living conditions were probably the most important cause for the difference in attack rates, wound severity, and systemic sequelae found between and within the units. CONCLUSIONS: Our study demonstrates the possible ramifications of the combination of a virulent and highly infective S. pyogenes strain and poor living conditions, and it emphasizes the importance of early intervention in such conditions.

Postexposure treatment with doxycycline for the prevention of tick-borne relapsing fever.

BACKGROUND: Tick-borne relapsing fever (TBRF) is an acute febrile illness. In Israel, TBRF is caused by Borrelia persica and is transmitted by Ornithodoros tholozani ticks. We examined the safety and efficacy of postexposure treatment to prevent TBRF. METHODS: In a double-blind, placebo-controlled trial, 93 healthy subjects with suspected tick exposure (52 with signs of tick bites and 41 close contacts--those without signs but with a similar risk of contact with ticks) were randomly assigned to receive either doxycycline (Dexxon, in a dose of 200 mg the first day and then 100 mg per day for four days) or placebo after presumed exposure to TBRF. Cases of TBRF were defined by fever and a positive blood smear. Serologic analysis for cross-reactivity to Borrelia burgdorferi and polymerase chain reaction (PCR) for the borrelia glpQ gene were also performed. RESULTS: After randomization, 47 subjects (26 with signs of tick bites and 21 close contacts) received doxycycline. Forty-six other subjects (26 with signs of tick bites and 20 close contacts) received placebo. All 10 cases of TBRF identified by a positive blood smear were in the placebo group of subjects with signs of a tick bite (P<0.001). These findings suggested a 100 percent efficacy of preemptive treatment (95 percent confidence interval, 46 to 100 percent). PCR for the borrelia glpQ gene was negative at baseline for all subjects and subsequently positive in all subjects with fever and a positive blood smear. Seroconversion was detected in eight of nine cases of TBRF. PCR and serum samples were negative for all of the other subjects tested. No major treatment-associated adverse effects were identified. CONCLUSIONS: Treatment with doxycycline is safe and efficacious in preventing TBRF after suspected exposure to ticks in a high-risk environment. (ClinicalTrials.gov number, NCT00237016 [ClinicalTrials.gov].).

Identification of risk factors for infection in an outbreak of Mycoplasma pneumoniae respiratory tract disease.

BACKGROUND: Mycoplasma pneumoniae is one of the most common pathogens that causes community-acquired respiratory tract infection. Outbreaks are well known, and all age groups are susceptible. An outbreak in an army training unit afforded an opportunity to identify possible risk factors for morbidity. METHODS: An outbreak of respiratory illness that occurred in a unit comprising 91 trainees was investigated and analyzed as a cohort study. M. pneumoniae infection was suspected on clinical grounds and was confirmed by polymerase chain reaction, culture, and serologic testing. Data regarding medical history, symptoms, signs, and laboratory tests were collected. RESULTS: During a period of 12 days, 41 soldiers (45.1%) had respiratory illnesses, of which 10 (11.0%) were pneumonia. Comparison of symptomatic and asymptomatic individuals revealed that smoking was associated with higher rates of disease (risk ratio, 2.1; 95% confidence interval [CI], 1.3-3.2; P<.005) and seroconversion (risk ratio, 2; 95% CI, 1.2-3.4; P=.03). In multivariate analysis, both lower acute immunoglobulin G values (adjusted odds ratio, 7.8; 95% CI, 1.4-42.5; P=.018) and smoking (adjusted odds ratio, 5.6; 95% CI, 1.5-20.4; P=.01) were associated with symptomatic infection; stratification according to smoking status revealed that immunoglobulin G levels among nonsmokers were protective. Patients who had pneumonia had lower lymphocyte counts (1400+/-258 vs. 2000+/-465 cells/microL; P=.001). CONCLUSIONS: Smoking and lower preexisting immunoglobulin G levels were strongly associated with M. pneumoniae respiratory infection. These findings emphasize the importance of immunity and cessation of smoking for the prevention of disease. The high attack rate emphasizes the extent of infection transmission among healthy persons living in close contact.

Detection of relapsing fever in human blood samples from Israel using PCR targeting the glycerophosphodiester phosphodiesterase (GlpQ) gene.

Relapsing fever caused by Borrelia persica is an acute tick-borne disease infecting people in the Middle East. A PCR test targeting the glycerophosphodiester phosphodiesterase (GlpQ) gene was used to detect infection in the blood of suspected relapsing fever patients. The assay detected infection in all 19 patients from Israel who were spirochetemic by blood smear examination and in two additional patients with clinical relapsing fever who were negative by smear examination. Patients were positive by PCR of blood only at the febrile stage and not during the incubation period prior to the appearance of clinical symptoms. Of 52 tick-bitten subjects who were tested and followed-up after being bitten by ticks, 10 developed symptoms of relapsing fever and all became positive by PCR following an earlier negative test. Partial sequencing of the 16S rRNA gene supported by phylogenetic analysis indicated that infection was caused by B. persica or a closely related species. A phylogenetic analysis of the GlpQ sequence showed that it was different yet closely related to other relapsing fever Borrelia spp. present in the Old World. The GlpQ PCR was positive also with the relapsing fever spirochetes B. recurrentis and B. crocidure but not with the Lyme disease agent B. burgdorferi DNA. A second modified GlpQ PCR was able to discriminate between probable B. persica and B. recurrentis and B. crocidurae infection. This study describes the first molecular assay for the diagnosis of relapsing fever caused by B. persica.

The effect of fermented yogurt on the prevention of diarrhea in a healthy adult population.

BACKGROUND: Probiotic dairy products are increasingly gaining popularity. Although the role of probiotic bacteria in the prevention and treatment of pediatric and antibiotic associated diarrhea is fairly well established, their role in the prevention of adult infectious diarrhea has not been well investigated. METHODS: Five hundred forty-one, young male military recruits were enrolled and randomly assigned to receive a yogurt containing Lactobacillus casei (n = 275) or a nonprobiotic yogurt (n = 266). The incidence and duration of diarrhea were documented and stool samples examined for bacteria and parasites. RESULTS: Five hundred and two participants were eligible for final analysis, 254 receiving probiotic yogurt and 248 in the control group. Seventy-one participants (14.14%) experienced diarrhea during the study period. The incidence of diarrhea in the probiotic group and the control group was 12.2% and 16.1%, respectively (P = .207). The mean duration of diarrhea was 3 +/- 1.95 days in the probiotic group and 2.6 +/- 1.08 days in the control group (P = .276). CONCLUSION: Our study demonstrated a nonsignificant trend for reduction of the incidence of diarrhea among healthy young adults consuming yogurt containing Lactobacillus casei . Further study is needed to evaluate the role of probiotics in adults.

Dynamics of pneumococcal acquisition and carriage in young adults during training in confined settings in Israel.

BACKGROUND: Outbreaks and sporadic cases of pneumococcal illness occur among young adults in confined settings. Our aim was to characterize pneumococcal acquisition and carriage among healthy young adults in Israel during military training in confined settings. METHODS: During the years 2007-2008, an observational longitudinal study was conducted in three cohorts of healthy soldiers, during a 7-month basic training period. Epidemiological data, oropharyngeal and nasopharyngeal cultures were sampled on 5 occasions: before and 3, 6, 12 and 24 weeks after start of training. Samples were processed within 2-18 hours. Relatedness of isolates was investigated by capsular typing of all isolates and pulsed-field gel electrophoresis to determine acquisition and transmission. Carriage and acquisition patterns were analyzed and multivariable logistic regression analysis was performed to assess the impact of time on acquisition after mixing, controlling for other covariates. RESULTS: Pneumococci were recovered on 202 of 1872 visits among 742 individuals, including 40 different serotypes. Mean carriage prevalence increased in all visits following training initiation. Acquisition during training was high, as 36.9% of individuals acquired pneumococci at least once during training, and for almost one fourth of the whole population this occurred during the first 6 weeks. Significant clustering was noted. Sharing drinking glass/bottle was found to be a significant and common risk factor for pneumococcal acquisition. CONCLUSIONS: Pneumococcal acquisition is highly frequent when young adults live in close contact in confined settings, especially early after mixing.

No association between histo-blood group antigens and susceptibility to clinical infections with genogroup II norovirus.

Noroviruses (NoVs) are a leading cause of viral gastroenteritis in humans. In the present study, the association between NoV susceptibility and the ABO histo-blood group was studied during 2 outbreaks of acute gastroenteritis in military units in Israel caused by genogroup II (GII) NoVs. The findings demonstrate that, unlike for genogroup I of NoV, there is no association between the ABO histo-blood group and clinical infection with GII NoVs. This is the largest study to test the association between NoVs, proven clinical infection with GII, and the ABO histo-blood group.

Long-term immunity in young adults after a single dose of inactivated Hepatitis A vaccines.

We evaluated in a prospective study the immune response of naïve subjects to a single dose of inactivated Hepatitis A vaccine. Ninety-seven percent of the vaccinees sero-converted 1 month after vaccination and 93% were still positive 2 years later. All of the vaccinees had a strong booster response 2 years after the single dose. Avaxim was more immunogenic than Vaqta for the primary dose (p = 0.01 for sero-positivity, p<0.001 for antibody level) but no differences were found after boosting with Avaxim. Performance of intense physical activity during the first month after a single vaccine dose was associated with lower antibody levels (p = 0.004). This study indicates that a single dose of inactivated HAV vaccine elicits protective immune memory for at least 2 years.

Community-based safety, immunogenicity, and transmissibility study of the Shigella sonnei WRSS1 vaccine in Israeli volunteers.

We describe the first community-based evaluation of Shigella sonnei strain WRSS1, a live, oral candidate vaccine attenuated by a 212-bp deletion in the virG (or icsA) plasmid virulence gene. Three single-dose regimens of WRSS1 (5 x 10(3) CFU, 2 x 10(4) CFU, and 4 x 10(5) CFU) were tested with cohorts of 15 adult volunteers. The vaccine was generally well tolerated at the 10(3)- and 10(4)-CFU doses. There were no fevers and there was one report of moderate diarrhea in 30 vaccinees; five additional vaccinees reported mild diarrhea. At the 10(5)-CFU dose, there were two reports of low-grade fevers and four reports of moderate diarrhea. The geometric means for immunoglobulin A (IgA) antibody-secreting cells (ASC) against lipopolysaccharide (LPS) were 30, 75, and 193 ASC per 10(6) peripheral blood mononuclear cells (PBMC) for the 10(3)-, 10(4)-, and 10(5)-CFU doses, respectively. The IgG means were 40, 46, and 135 ASC per 10(6) PBMC, respectively. The 10(4)-CFU dose of WRSS1 gave the best balance of safety and immunogenicity, since all vaccinees had a significant IgA ASC response and 73% had a response of more than 50 ASC. The anti-LPS seroconversion rate (threefold) for IgA was 60% and the IgG rate was 27% for the 10(4)-CFU cohort. Each vaccinee and a cohabitating household contact delivered daily perianal stool swabs for bacteriological culture. WRSS1 colonized vaccinees for a median of 5 days, and one individual excreted WRSS1 intermittently for 23 days. None of the 45 household contacts were colonized with WRSS1 after a cumulative 192 days of cohabitation with colonized vaccinees, suggesting that adventitious vaccine spread was not common in the community setting.