Shigella gastroenteritis: clinical and epidemiological aspects, and antibiotic susceptibility

Prevalence of Multidrug-Resistant Escherichia coli Isolated from Drinking Water Sources

The control of infectious diseases is badly endangered by the rise in the number of microorganisms that are resistant to antimicrobial agents. This is because infections caused by resistant microorganisms often fail to respond to conventional treatment, resulting in prolonged illness and greater risk of death. Antimicrobial-resistant bacteria are also present in various water sources. This study therefore sought to document the microbiological quality and antibiograms of bacterial isolates (E. coli strains) from six different water sources in order to determine their safety for human consumption and to provide updated antibiotic data for pragmatic treatment of patients. Bacteria isolation and identification was done using API and conventional methods. Antibiotic susceptibility testing was conducted using the Kirby-Bauer method. Results obtained indicated that all the water sources tested were of poor quality. Bacteria isolated included E. coli, Enterobacter spp., Klebsiella spp., Salmonella typhi, Streptococcus spp., Proteus vulgaris, Vibrio cholera, Shigella spp., Pseudomonas aeruginosa, and Enterococcus faecalis. The prevalence of multidrug-resistant E. coli was 49.48%. E. coli isolates showed high resistance patterns to the tested antibiotics. They were most resistant to penicillin (32.99%), cefuroxime (28.87%), erythromycin (23.71%), and tetracycline (21.45%). In contrast, they were susceptible to nitrofurantoin (93.8%), cefotaxime and amikacin (91.75%), gentamicin (90.7%), nalidixic acid (89.65%), ciprofloxacin (74.2%), chloramphenicol (69.07%), pipemidic acid (65.97%), and cefuroxime (52.58%). Sixty-three percent (63%) of the multidrug-resistant E. coli strains recorded a multiple antibiotic resistance (MAR) index value >0.2. The susceptible antibiotics, especially the nitrofurantoin, are hence recommended in the practical treatment of waterborne bacterial diseases.

The changing epidemiology of bacillary dysentery and characteristics of antimicrobial resistance of Shigella isolated in China from 2004-2014

Background

Bacillary dysentery caused by bacteria of the genus Shigella is a significant public health problem in developing countries such as China. The objective of this study was to analyze the epidemiological pattern of bacillary dysentery, the diversity of the causative agent, and the antimicrobial resistance patterns of Shigella spp. for the purpose of determining the most effective allocation of resources and prioritization of interventions.

Methods

Surveillance data were acquired from the National Infectious Disease Information Reporting System (2004–2014) and from the sentinel hospital-based surveillance system (2005–2014). We analyzed the spatial and temporal distribution of bacillary dysentery, age and sex distribution, species diversity, and antimicrobial resistance patterns of Shigella spp.

Results

The surveillance registry included over 3 million probable cases of bacillary dysentery during the period 2004–2014. The annual incidence rate of bacillary dysentery decreased from 38.03 cases per 100,000 person-years in 2004 to 11.24 cases per 100,000 person-years in 2014. The case-fatality rate decreased from 0.028% in 2004 to 0.003% in 2014. Children aged <1 year and 1–4 years were most affected, with higher incidence rates (228.59 cases per 100,000 person-years and 92.58 cases per 100,000 person-years respectively). The annual epidemic season occurred between June and September. A higher incidence rate of bacillary dysentery was found in the Northwest region, Beijing and Tianjin during the study period. Shigella flexneri was the most prevalent species that caused bacillary dysentery in China (63.86%), followed by Shigella sonnei (34.89%). Shigella isolates were highly resistant to nalidixic acid (89.13%), ampicillin (88.90%), tetracycline (88.43%), and sulfamethoxazole (82.92%). During the study period, isolates resistant to ciprofloxacin and cefotaxime increased from 8.53 and 7.87% in 2005 to 44.65 and 29.94% in 2014, respectively.

Conclusions

The incidence rate of bacillary dysentery has undergone an obvious decrease from 2004 to 2014. Priority interventions should be delivered to populations in northwest China and to individuals aged <5 years. Antimicrobial resistance of Shigella is a serious public health problem and it is important to consider the susceptibility profile of isolates before determining treatment.

Clinical characteristics and antibiotic resistance of Shigella gastroenteritis in Ankara, Turkey between 2003 and 2009, and comparison with previous reports

OBJECTIVES

The aim of this study was to define the epidemiological, clinical, and antibiotic susceptibility patterns of Shigella gastroenteritis cases occurring during the years 2003-2009 and to compare results with those of the years 1987-2002.

METHODS

A hospital-based study was conducted over a 22-year period. All 238 Shigella strains isolated between 2003 and 2009 were compared to 618 isolates from the period 1987-1994 and 218 Shigella strains isolated during 1995-2002 with regard to antimicrobial resistance patterns and patient clinical characteristics.

RESULTS

The predominant species during all periods was Shigella sonnei, with an increasing predominance across the periods (64.0%, 71.5%, and 87.8%, respectively; p<0.001). Neither the prevalence of bloody diarrhea nor other clinical characteristics changed across the study periods, except for the prevalence of dehydration, which increased (11.0%, 20.6%, and 28.6%, respectively; p<0.001). During the period 2003-2009, 69.9% of Shigella were resistant to trimethoprim/sulfamethoxazole, 35.8% to ampicillin, and 4.7% to nalidixic acid. No case resistant to ciprofloxacin was detected. Multidrug resistance was also found to be similar in the last two periods (24.0% vs. 28.1%, respectively).

CONCLUSIONS

There was both a microbiological and a clinical change in childhood Shigella gastroenteritis cases over the 22 years. The antibiotic resistance pattern appears to have remained stable over the last two periods. There is a need to re-examine the criteria and clinical management guidelines for suspected shigellosis cases.

Waterborne epidemic outbreak of Shigella sonnei gastroenteritis in Santa Maria de Palautordera, Catalonia, Spain

In August 2002 an outbreak of Shigella sonnei infection occurred in a Spanish town of 6343 inhabitants. In total, 756 people developed acute gastroenteritis and 181 cases were shigella-confirmed. The peak incidence was during 5-6 August 2002. The estimated primary attack rate was 9.97%; the attack rate for secondary cases was 38%. The <15 years ago group was most affected (16.49%). The town and its surroundings were served by two water systems, A and B. The cases had consumed water provided by system A (attack rate 164 cases/1000 population). Microbiological analysis of water from system A did not show the presence of coliform bacteria or shigella. This shigellosis outbreak was the largest reported in Spain. The impact of the epidemic was probably greater than the incidence detected.

Molecular epidemiology of Shigella flexneri in a long-stay psychiatric nursing center during 2001 to 2003

With six separate wards accommodating more than 1,600 patients, V Nursing Center (VNC) is a long-stay psychiatric nursing center in eastern Taiwan. During 2001 to 2003, 39 shigellosis cases occurred in VNC. Different from the notion that most cases of shigellosis are caused by Shigella sonnei, all except one of these cases were caused by S. flexneri, with the remaining one caused by an S. sonnei isolate. O-antigen serotyping showed that the 38 S. flexneri strains were of either type 1a (n = 20) or 4a (n = 18), two less prevalent serotypes in Taiwan. NotI-based pulsed-field gel electrophoresis analyses performed with 8 type 1a non-VNC strains and 9 type 4a non-VNC strains isolated from 1996 to 2003 for comparison divided the 28 type 1a strains and the 27 type 4a strains into 7 and 10 subtypes, designated subtypes P1A to P1G and subtypes P4A to P4J, respectively. Subtypes P1A and P4A, which appeared in three consecutive years in VNC as well as outside of VNC, are the most prevalent subtypes. Analyses of the relatedness of the VNC strains on the basis of the banding patterns grouped the type 1a and 4a strains into four and five clusters, respectively. All except one of the type 1a strains had 95% similarity, indicating that they had a common parent, whereas the type 4a strains had similarities that ranged from 77 to 93%, suggesting that they were of diverse origins. In two of the outbreaks, less related subtypes of the type 4a strains were found in the same VNC wards in consecutive years, suggesting the possible existence of different subtypes in VNC all the time. Antibiotic susceptibility testing showed that all except one of the S. flexneri strains were sensitive to at least seven antibiotics; the remaining isolate was sensitive to three antibiotics. The data from the latter tests should be helpful for selection of proper treatments for S. flexneri infections in Taiwan.

Shigella antibiotic resistance in central Turkey: comparison of the years 1987-1994 and 1995-2002

BACKGROUND

The epidemiology and antibiotic susceptibility of Shigella species changes over time. Updated susceptibility knowledge is necessary for appropriate empirical antibiotic treatment.

METHODS

In this study the clinical characteristics and the antibiotic susceptibility test results of Shigella species isolated from patients admitted to Hacettepe University Ihsan Dogramac Children's Hospital Diarrheal Diseases Training and Treatment Unit between 1995-2002 (n = 218) were evaluated. The results were compared with the results of 1987-1994 from the same center (n = 618).

RESULTS

The predominant species was S. sonnei in both periods with increasing prevalence in the later period (64% and 71.5% respectively, P < 0.05). Although the prevalence of bloody diarrhea among Shigella cases did not change between periods, the prevalence of mild to moderate dehydration (11% and 20.6%) increased. Approximately 40% of cases were prescribed antibiotics on the suspicion of shigellosis. When the two periods were compared, Shigella resistance to trimethoprim/sulfamethoxazole increased from 39% to 70% (P < 0.0001), whereas resistance to ampicillin decreased from 41% to 23% (P < 0.0001). However, the resistance of S. flexneri to ampicillin was found to be quite high (72.9%) between 1995-2002. No Shigella species resistant to ciprofloxacin was detected. Multi-drug resistance was present in 52 (24%) of the cases, of which 10 were S. sonnei (6.3%) and 42 S. flexneri (26.4%) (P < 0.0001).

CONCLUSION

The need to treat all Shigella cases in areas where S. sonnei is predominant should be reevaluated, as should the appropriate empirical antibiotic.

Shigella infections in children: new insights

Shigellosis , the acute enteric infection caused by bacteria of the genus Shigella , has a worldwide distribution with an estimated annual incidence of 164.7 million cases, of which 163.2 million occur in developing countries, and 1.1 million deaths. Sixty-nine percent of all episodes and 61 percent of all Shigella -related deaths involve children younger than 5 years old. In the United States, 10,000 to 15,000 cases of shigellosis are reported each year. Although usually confined to the colonic mucosa, shigellosis sometimes can cause extraintestinal complications. Recent publications have shed light on the clinical characteristics of Shigella -induced bacteremia, surgical complications, urogenital symptoms, and neurologic manifestations, and on the unique manifestations in the neonatal period. The mainstay of treatment of shigellosis in children is correction of the fluid and electrolyte loss, which often is achieved by the administration of oral rehydration solutions. Appropriate antibiotic therapy shortens the duration of both clinical symptoms and fecal excretion of the pathogen. However, the increasing antimicrobial resistance of shigellae worldwide constitutes a major problem. Regarding the pathophysiology of shigellosis and its complications, recent data not only elucidated the molecular mechanisms involved but also linked manifestations of disease to the interplay of bacterial virulence factors and host responses. The improved understanding of the pathophysiology is hoped to lead to innovative therapeutic approaches against shigellosis and new generations of vaccine candidates.

Shigellosis of childhood in northern Greece: epidemiological, clinical and laboratory data of hospitalized patients during the period 1971-96

The aim of this study was to evaluate epidemiological, clinical and laboratory data of shigellosis in children from northern Greece, hospitalized in our department during the period 1971-96. In total, 422 cases of shigellosis, aged 1 month to 14 y (238M, 184F) were hospitalized during the study period. The annual distribution was approximately stable until 1990, the mean number of cases per year being about 20. During the last 4 y the incidence significantly decreased. Shigella was serotyped in 138/422 cases. Seventy six of the strains were S. flexneri (55%) and 56 S. sonnei (40%). In the majority of cases the clinical picture was mild. Severe dehydration was seen in only 6 patients. Ninety four patients (22%) had extra-intestinal manifestations. Most common of these were convulsions (16%) and, less frequently, disturbances of consciousness (n = 26), rash (n = 9), shock and disseminated intravascular coagulopathy (n = 2), nerve paralysis (n = 2), severe anaemia (n = 2) and haemolytic-uraemic syndrome (n = 1). Nine patients had acute encephalopathy of 12 h to 12 d duration. It is important to note that all these cases recovered completely with no residual neurological deficit, except for 1 girl who developed temporal epilepsy 8 y later. Spinal fluid was normal in all 42 examined patients. Antibiotics were given to 212 of 422 patients, mainly during the first half of the study period. Shigella resistance to antibiotic was significant for cotrimoxazole (24%) and ampicillin (16%). All patients were cured. Shigellosis is a mild disease in our area, with a decreasing prevalence.