During October 2021, the County of San Diego Health and Human Services Agency identified five cases of shigellosis among persons experiencing homelessness (PEH). We conducted an outbreak investigation and developed interventions to respond to shigellosis outbreaks among PEH. Confirmed cases occurred among PEH with stool-cultured Shigella sonnei; probable cases were among PEH with Shigella-positive culture-independent diagnostic testing. Patients were interviewed to determine infectious sources and risk factors. Fifty-three patients were identified (47 confirmed, 6 probable); 34 (64%) were hospitalised. None died. No point source was identified. Patients reported inadequate access to clean water and sanitation facilities, including public restrooms closed because of the COVID-19 pandemic. After implementing interventions, including handwashing stations, more frequent public restroom cleaning, sanitation kit distribution, and isolation housing for ill persons, S. sonnei cases decreased to preoutbreak frequencies. Improving public sanitation access was associated with decreased cases and should be considered to prevent outbreaks among PEH.

Shigellosis causes significant morbidity and mortality in developing and developed countries, mostly among infants and young children. The World Health Organization estimates that more than one million people die from Shigellosis every year. In order to evaluate trends in Shigellosis in Israel in the years 2002–2015, we analysed national notifiable disease reporting data. Shigella sonnei was the most commonly identified Shigella species in Israel. Hospitalisation rates due to Shigella flexenri were higher in comparison with other Shigella species. Shigella morbidity was higher among infants and young children (age 0–5 years old). Incidence of Shigella species differed among various ethnic groups, with significantly high rates of S. flexenri among Muslims, in comparison with Jews, Druze and Christians. In order to improve the current Shigellosis clinical diagnosis, we developed machine learning algorithms to predict the Shigella species and whether a patient will be hospitalised or not, based on available demographic and clinical data. The algorithms’ performances yielded an accuracy of 93.2% (Shigella species) and 94.9% (hospitalisation) and may consequently improve the diagnosis and treatment of the disease.

French Guiana, a tropical country, is characterised by a young and multi-ethnic population. Difficulties in accessing safe water sources lead to outbreaks of gastroenteritis. The objectives of this study were (1) to describe the microbiological profile of shigella strains isolated in western French Guiana, including antimicrobial susceptibility and the distribution of strains in terms of species and serotypes and (2) to estimate the incidence of shigellosis in children under 5 years old. A retrospective observational study was conducted of 213 cases of shigellosis diagnosed in the biology department of the hospital centre for western French Guiana between 2000 and 2012 in children under 5 years old. The serogroups (formerly known as species) that predominates in French Guiana was Shigella flexneri. No resistance was observed to fluoroquinolones or to third-generation cephalosporins. The average incidence of shigellosis in children under 5 years old in western French Guiana was estimated at 189.6 cases per 100 000 inhabitants per year. Shigellosis is a public health problem in western French Guiana. These infections suggest the difficulties in accessing safe water sources and the lack of public sanitation. A quadrivalent vaccine containing Shigella sonnei and three serotypes of S. flexneri (S. flexneri 2a, 3a and 6) could provide broad coverage against shigella infections.

Shigellosis is endemic in most developing countries and thus a known risk in refugees and internally displaced persons. In 2015, a massive influx of refugees into Greece, due to the political crisis in the Middle East, led to the development of appropriate conditions for outbreaks of communicable diseases as shigellosis. We present a cluster of 16 shigellosis cases in refugees, detected by the implementation of a syndromic notification system in one transit centre in Athens, between 20 August and 7 October 2015. Both Shigella flexneri (n = 8) and S. sonnei (n = 8) were identified, distributed in various serotypes. All tested isolates (n = 13) were multidrug resistant; seven were CTX-M-type extended-spectrum β-lactamase producers. Our results indicate lack of a potential common source, although pulsed-field gel electrophoresis typing results revealed small clusters in isolates of the same serotype indicating possible limited person-to-person transmission without identifying secondary community cases related to the refugees. To prevent the spread of shigellosis, empirical antibiotic treatment as well as environmental hygiene measures were implemented. The detection of multi-drug resistance is important for determining the appropriate empirical antibiotic treatment for the more severe cases, while at the same time real-time typing is useful for epidemiological investigation and control measures.

There is limited information on percent expenditure of household income due to childhood diarrhoea especially in rural Bangladesh. A total of 4205 children aged <5 years with acute diarrhoea were studied. Percent expenditure was calculated as total expenditure for the diarrhoeal episode divided by monthly family income, multiplied by 100. Overall median percent expenditure was 3·04 (range 0·01–94·35). For Vibrio cholerae it was 6·42 (range 0·52–82·85), for enterotoxigenic Escherichia coli 3·10 (range 0·22–91·87), for Shigella 3·17 (range 0·06–77·80), and for rotavirus 3·08 (range 0·06–48·00). In a multinomial logistic regression model, for the upper tertile of percent expenditure, significant higher odds were found for male sex, travelling a longer distance to reach hospital (⩾median of 4 miles), seeking care elsewhere before attending hospital, vomiting, higher frequency of purging (⩾10 times/day), some or severe dehydration and stunting. V. cholerae was the highest and rotavirus was the least responsible pathogen for percent expenditure of household income due to childhood diarrhoea.

The enteric pathogens causing diarrhoea impair children's health severely. This study retrospectively analysed 1577 pathogens isolated from inpatients and outpatients in six hospitals located in Northern (Inner Mongolia), Northeastern (Hebei), Eastern (Shanghai and Jiangsu), Southern (Hainan) and Central (Hubei) China between 2008 and 2013. Of the 1577 enteric pathogens, Salmonella presented with the highest frequency (36·0%), followed by diarrhoeagenic Escherichia coli (23·7%), Staphylococcus aureus (15·0%), Shigella (13·1%), and Aeromonas (4·6%). The predominant pathogens varied in different regions of China, with Salmonella most prevalent in Shanghai and Hainan, diarrhoeagenic E. coli most prevalent in Inner Mongolia, Jiangsu and Hubei, and Shigella most prevalent in Hebei. Enteric pathogens were more frequently isolated in males (56·9%) than in females (43·1%). The highest proportion of all enteric pathogens was found in infants (67·6%) with a peak in summer and autumn (68·5%). Antimicrobial susceptibility assay demonstrated that Shigella was more resistant to ampicillin, ceftriaxone and sulfamethoxazole than Salmonella. Of the top two serotypes in Salmonella, Typhimurium was more resistant to ciprofloxacin, sulfamethoxazole and chloramphenicol than Enteritidis (P < 0·001). Meanwhile, the resistance rates of Shigella flexneri against ampicillin/sulbactam, ciprofloxacin, and chloramphenicol were significantly higher than those of Shigella sonnei (P < 0·001). Multidrug resistance was apparent in 58·2% of Shigella and 45·9% of Salmonella, and this phenomenon was more pronounced in S. flexneri.

In 2006 we initiated an enhanced laboratory-based surveillance of Salmonella and Shigella infections in Shanghai, China. A total of 4483 Salmonella and 2226 Shigella isolates were recovered from stool specimens by 2012. In 80 identified Salmonella serovars, Enteritidis (34·5%) and Typhimurium (26·2%) were the most common. Shigella (S.) sonnei accounted for 63·9% of human Shigella infections over the same time period, and replaced S. flexneri to become the primary cause of shigellosis since 2010. Overall, a high level of antimicrobial resistance was observed in Salmonella and Shigella, particularly to nalidixic acid, ampicillin, and tetracycline. Ciprofloxacin resistance was common in Salmonella Typhimurium (21·0%) and S. flexneri (37·6%). The cephalosporin resistance in both pathogens also increased over the years, ranging from 3·4% to 7·0% in Salmonella, and from 10·4% to 28·6% in Shigella. Resistance to multiple antimicrobials was also identified in a large number of the isolates. This study provides insight into the distribution of Salmonella and Shigella in diarrhoeal diseases.

We provide an update on the epidemiology of shigellosis in Israel using data generated by a sentinel laboratory-based surveillance network for the period 1998–2012. The average annual incidence of culture-proven shigellosis was 97/100 000. We estimated that each case of shigellosis accounted for 25 cases in the community indicating the high burden of disease. Orthodox Jewish communities, living in highly crowded conditions and with a high number of children aged <5 years were the epicentre of country-wide biennial propagated epidemics of S. sonnei shigellosis. S. flexneri was the leading Shigella serogroup in Israeli Arabs. S. flexneri 2a and S. flexneri 6 alternated as the most common serotypes. Both S. sonnei and S. flexneri isolates showed high rates of resistance to ampicillin and trimethoprim/sulfamethoxazole and very low rates of resistance to quinolones and third-generation cephalosporins. Shigellosis due to S. sonnei conferred 81% (95% confidence interval 69–89) protection against the homologous Shigella serotype when epidemic exposure re-occurred 2 years later. These data are of value in the process of Shigella vaccine development.

The study aimed to determine the geographical diversity in seasonality of major diarrhoeal pathogens among 21 138 patients enrolled between 2010 and 2012 in two urban and two rural sites in Bangladesh under the surveillance system of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). Distinct patterns in seasonality were found for rotavirus diarrhoea which peaked in winter across the sites (December and January) and dipped during the rainy season (May) in urban Dhaka, August in Mirpur and July in Matlab, equated by time-series analysis using quasi-Poisson regression model. Significant seasonality for shigellosis was observed in Dhaka and rural Mirzapur. Cholera had robust seasonality in Dhaka and Matlab in the hot and rainy seasons. For enterotoxogenic Escherichia coli (ETEC) diarrhoea, clearly defined seasonality was observed in Dhaka (summer). Understanding the seasonality of such pathogens can improve case management with appropriate therapy, allowing policy-makers to identify periods of high disease burden.

The study identified the common aetiological agents and prominent clinical features of dysentery cases in children aged <5 years and compared this to non-dysentery diarrhoeal cases from the same population. From January 2010 to December 2011, 2324 children aged <5 years received treatment at Kumudini Hospital, of which 682 (29%) presented with dysentery. Of the dysenteric children, aetiology could not be determined for over half (61%). Shigella spp. accounted for 32% of dysentery cases. Significant associations were found between presence of blood in stool and: child age (24–59 months) [odds ratio (OR) 2·21, 95% confidence interval (CI) 1·49–3·27], no treatment of drinking water at home (OR 2·00, 95% CI 1·09–3·67), vomiting (OR 0·19, 95% CI 0·14–0·25), abdominal pain (OR 4·68, 95% CI 3·24–6·77), straining (OR 16·45, 95% CI 11·92–22·69), wasting (OR 1·66, 95% CI 1·15–2·41), and presence of Shigella in stool (OR 6·25, 95% CI 4·20–9·29) after controlling for confounders. This study makes it clear that appropriate public health strategies are needed to reduce the burden of dysentery in Bangladesh.

Although immediate notification of a case is crucial for epidemic control, clinicians may delay notification due to uncertainties in diagnosis, reflecting a trade-off between timeliness and the accuracy of surveillance. We assessed this trade-off for four epidemic-prone diseases that require immediate notification of suspected cases: shigellosis, typhoid fever, paratyphoid fever, and cholera in the Korean National Notifiable Disease Surveillance System data for 2001–2007. Timeliness was measured as the time to registration (TR), being the time interval from symptom onset to notification by the clinician to the local public health centre. We introduced a new index, ‘time-accuracy trade-off ratio’ to indicate time saved by clinical vs. laboratory-based notifications. Clinical notifications comprised 34·4% of total notifications, and these showed a shorter median TR than laboratory-based notifications (1–4 days). The trade-off ratio was greatest for shigellosis (3·3 days), and smallest for typhoid fever (0·6 days). A higher trade-off ratio provides stronger evidence for clinical notification without waiting for laboratory confirmation.

The aim of this study was to retrospectively assess the value of whole genome sequencing (WGS) compared to conventional typing methods in the investigation and control of an outbreak of Shigella sonnei in the Orthodox Jewish (OJ) community in the UK. The genome sequence analysis showed that the strains implicated in the outbreak formed three phylogenetically distinct clusters. One cluster represented cases associated with recent exposure to a single strain, whereas the other two clusters represented related but distinct strains of S. sonnei circulating in the OJ community across the UK. The WGS data challenged the conclusions drawn during the initial outbreak investigation and allowed cases of dysentery to be implicated or ruled out of the outbreak that were previously misclassified. This study showed that the resolution achieved using WGS would have clearly defined the outbreak, thus facilitating the promotion of infection control measures within local schools and the dissemination of a stronger public health message to the community.

The serotype distribution and susceptibility to 14 antimicrobial agents of 526 isolates of Shigella spp. from four hospitals in Sun county, Henan province, China during 2001–2008, were analysed to identify associations of serotypes with resistance trends. S. flexneri was the most frequent species (92·4%), the remainder was S. sonnei. The prevalent serotype of S. flexneri was 2a (26·7%). Almost all (>99%) isolates were resistant to tetracycline, nalidixic acid and pipemidic acid; >80% were resistant to chloramphenicol, amoxicillin and co-trimoxazole but less than 5% were resistant to polymyxin B, furazolidone, cefotaxime and gentamicin. S. flexneri showed statistically significant higher resistance than S. sonnei to amoxicillin, ampicillin, chloramphenicol and ciprofloxacin but resistance to co-trimoxazole was more common in S. sonnei than in S. flexneri. These results emphasize that monitoring of emerging resistance in Shigella isolates is essential for timely and appropriate recommendations for antimicrobial therapy.

Shigella is an important bacterial cause of infectious diarrhoea globally. The Shigella human challenge model has been used since 1946 for a variety of objectives including understanding disease pathogenesis, human immune responses and allowing for an early assessment of vaccine efficacy. A systematic review of the literature regarding experimental shigellosis in human subjects was conducted. Summative estimates were calculated by strain and dose. While a total of 19 studies evaluating nine strains at doses ranging from 10 to 1 × 1010 colony-forming units were identified, most studies utilized the S. sonnei strain 53G and the S. flexneri strain 2457T. Inoculum solution and pre-inoculation buffering has varied over time although diarrhoea attack rates do not appear to increase above 75–80%, and dysentery rates remain fairly constant, highlighting the need for additional dose-ranging studies. Expansion of the model to include additional strains from different serotypes will elucidate serotype and strain-specific outcome variability.

Historically, Shigella sonnei has dominated other Shigella species infection in men who have sex with men (MSM) in Montréal. In early 2010, Toronto reported increased proportions of the more pathogenic S. flexneri, HIV co-infection and MSM in shigellosis cases since 2009. Analytical methods were used to assess whether S. flexneri had dominated Montréal's MSM cases since 2009 and whether changes had occurred in notifications in MSM and HIV-co-infected MSM. S. flexneri increased by 6·7% per month since 2007 and predominated in MSM since 2009 without changes in HIV co-infection or similar shifts in the general population. The results suggest that the surveillance of Shigella species in order to detect species shifts is beneficial for surveillance, given the potential for increased transmission and severity of S. flexneri in HIV-positive MSM.

Shigella flexneri 4a caused sustained outbreaks in a large long-stay psychiatric centre, Taiwan, 2001–2006. Trimethoprim-sulphamethoxazole (SXT) prophylaxis was administered in 2004. We recovered 108 S. flexneri 4a isolates from 83 symptomatic (including one caregiver) and 12 asymptomatic subjects (11 contacts, one caregiver). The isolates were classified into eight antibiogram types and 15 genotypes (six clusters) by using antimicrobial susceptibility testing and pulsed-field gel electrophoresis of NotI-digested DNA, respectively. These characteristics altered significantly after SXT prophylaxis (P < 0·05), with concomitant emergence of SXT-resistant isolates in two antibiogram types. P01 (n = 71), the predominant epidemic genotype, caused infection in two caregivers and five patients under their care; two P01 isolates were recovered from the same patient 6 months apart. These results indicate the importance of sustained person-to-person transmission of S. flexneri 4a by long-term convalescent, asymptomatic or caregiver carriers, and support the emergence of SXT-resistant strains following selective pressure by SXT prophylaxis.

We examined reported outbreaks of foodborne shigellosis in the USA from 1998 to 2008 and summarized demographic and epidemiological characteristics of 120 confirmed outbreaks resulting in 6208 illnesses. Most reported foodborne shigellosis outbreaks (n = 70, 58%) and outbreak-associated illnesses (n = 3383, 54%) were restaurant-associated. The largest outbreaks were associated with commercially prepared foods distributed in multiple states and foods prepared in institutional settings. Foods commonly consumed raw were implicated in 29 (24%) outbreaks and infected food handlers in 28 (23%) outbreaks. Most outbreaks (n = 86, 72%) were caused by Shigella sonnei. Targeted efforts to reduce contamination during food handling at multiple points in the food processing and distribution system, including food preparation in restaurants and institutional settings, could prevent many foodborne disease outbreaks and outbreak-related illnesses including those due to Shigella.

Diversity within Shigella dysenteriae (n=40) and Shigella boydii (n=30) isolates from children living in Egypt aged <5 years was investigated. Shigella-associated diarrhoea occurred mainly in summer months and in children aged <3 years, it commonly presented with vomiting and fever. Serotypes 7 (30%), 2 (28%), and 3 (23%) accounted for most of S. dysenteriae isolates; 50% of S. boydii isolates were serotype 2. S. dysenteriae and S. boydii isolates were often resistant to ampicillin, chloramphenicol and tetracycline (42%, 17%, respectively), although resistance varied among serotypes. Pulsed-field gel electrophoresis separated the isolates into distinct clusters correlating with species and serotype. Genetic differences in trimethoprim/sulfamethoxazole and β-lactam-encoding resistance genes were also evident. S. dysenteriae and S. boydii are genetically diverse pathogens in Egypt; the high level of multidrug resistance associated with both pathogens and resistance to the most available inexpensive antibiotics underlines the importance of continuing surveillance.

On 13 November 2009, the authorities of Flemish Brabant, Belgium, received an alert concerning a potential outbreak of Shigella sonnei at a public institution. A study was conducted to assess the extent, discover the source and to implement further measures. We performed a matched case-control study to test an association between shigellosis and canteen-food consumption. Water samples and food handlers' faecal samples were tested. The reference laboratory characterized the retrospectively collected Shigella specimens. We found 52 cases distributed over space (25/35 departments) and time (2 months). We found a matched odds ratio of 3·84 (95% confidence interval 1·02–14·44) for canteen-food consumption. A food handler had travelled to Morocco shortly before detection of the first laboratory-confirmed case. Water samples and food handlers' faecal samples tested negative for Shigella. Confirmed cases presented PFGE profiles, highly similar to archived isolates from Morocco. Foodborne transmission associated with the canteen was strongly suspected.

We determined the extent by which mandatory reporting on isolates of Shigella and Salmonella underestimates the burden of diarrhoeal diseases in individuals aged <17 years in Israel and examined paediatricians' knowledge, attitudes and practices related to patient visits with diarrhoeal diseases. Sources of data were a nationwide population-based telephone survey for presence of diarrhoeal diseases, Maccabi Healthcare Services databases and a mail survey among its paediatricians. Monte Carlo simulation and rate estimates for all stages, from visit to physician to reporting on a culture-confirmed case of shigellosis or salmonellosis, were used to determine the underestimation factor. Of 1492 children, 5·7% reported a diarrhoeal episode during the 2 weeks prior to interview. The rate of visiting a physician with and without fever was 86% and 16%, respectively. A stool culture was performed for around 20% of patients and the isolation rates were 7·1% for Shigella and 2·1% for Salmonella. Paediatricians (n=214) ranked very young age of patient and the complaint ‘bloody diarrhoea’ as the most important determinants. We estimated that one reported isolate of Shigella or Salmonella represented 152 diarrhoeal episodes of all aetiologies. This estimate is important for further assessments of the true burden of diarrhoeal diseases.