Prevalence of antibiotic resistance pattern in shigella isolates procured from pediatric patients at Faisalabad - Pakistan

Shigella infection (shigellosis) is an intestinal disease caused by a shigella isolates belongs to a family Enterobacteriacea. Watery diarrhea, abdominal pain and tenesmus are the prominent symptoms of shigella infection. The present study was designed to determine period prevalence and antimicrobial susceptibility of Shigella species recovered from stool specimens obtained from diarrheal paediatric patients under 5 years of age. This cross-sectional study was carried out for a period of six months (Jan to June, 2016). All Shigella isolates were identified based on colony morphology, microscopic characteristics, and biochemical characteristics. After applying Kirby Baur disc diffusion method only 22 (18.96%) stool specimens were found positive for Shigella isolates among the 116 stool specimens. The isolates were also found susceptible to Levofloxacin (72.72%), Azithromycin (59.09%), and Cefotaxime (40.90%). However, the said isolates were resistant to Lincomycin (100%) and Penicillin-G (100%), followed by Amoxicillin (95.45%) and Oxacillin (95.45%). The chi-square test was used to check the close association among antimicrobial agents used and as highly significant (p-value < 2.2e-16). Based on antimicrobial susceptibility findings, Levofloxacin, Azithromycin and Cefotoxime were found effective for the control of shigellosis.

Chemical Profile, Antioxidant Properties and Antimicrobial Activities of Malaysian Heterotrigona itama Bee Bread

The aim of the study was to determine the chemical profile, antioxidant properties and antimicrobial activities of Heterotrigona itama bee bread from Malaysia. The pH, presence of phytochemicals, antioxidant properties, total phenolic content (TPC) and total flavonoid content (TFC), as well as antimicrobial activities, were assessed. Results revealed a decrease in the pH of bee bread water extract (BBW) relative to bee bread ethanolic extract (BBE) and bee bread hot water extract (BBH). Further, alkaloids, flavonoids, phenols, tannins, saponins, terpenoids, resins, glycosides and xanthoproteins were detected in BBW, BBH and BBE. Also, significant decreases in TPC, TFC, DPPH activity and FRAP were detected in BBW relative to BBH and BBE. We detected phenolic acids such as gallic acid, caffeic acid, trans-ferulic acid, trans 3-hydroxycinnamic acid and 2-hydroxycinnamic acid, and flavonoids such as quercetin, kaempferol, apigenin and mangiferin in BBE using high-performance liquid chromatography analysis. The strongest antimicrobial activity was observed in Klebsilla pneumonia (MIC₅₀ 1.914 µg/mL), followed by E. coli (MIC₅₀ 1.923 µg/mL), Shigella (MIC₅₀ 1.813 µg/mL) and Salmonella typhi (MIC₅₀ 1.617 µg/mL). Bee bread samples possess antioxidant and antimicrobial properties. Bee bread contains phenolic acids and flavonoids, and could be beneficial in the management and treatment of metabolic diseases.

Antimicrobial resistance in Shigella species: Our five years (2015-2019) experience in a tertiary care center in north India

PURPOSE

Shigella is the second leading cause of diarrhoeal mortality especially in children <5 years of age in African and Asian countries. Rapid changes are occurring in the epidemiology of shigellosis and Shigella are increasingly becoming highly drug resistant. To determine the serogroup distribution and antimicrobial resistance of Shigella isolated at our tertiary care centre in North India.

METHODS

A retrospective study was conducted where demographic details along with antimicrobial susceptibility data of Shigella isolated from stool specimens from 1^st January 2015 till 31^st December 2019 were retrieved from records and analyzed by WHONET 2019 software.

RESULTS

Shigella species was isolated in 1.31% (n = 137) of a total of 10,456 stool samples. Males predominated (n = 82; 59.8%) and majority of cases were admitted (n = 94; 68.6%). Children ≤5 years of age (n = 47; 34.3%) were the most commonly affected. Adults in the 21-40 age group contributed 27% of cases (n = 37). Overall, Shigella flexneri (n = 87; 63.5%) was the most common serogroup followed by non-agglutinable Shigella (n = 28; 20.4%) while Shigella sonnei (n = 12, 8.8%) and Shigella boydii (n = 9, 6.6%) fluctuated over the years. Shigella dysenteriae reappeared in 2019 after a hiatus of ten years. Overall, 45.3% (n = 62) of isolates were multidrug resistant to CLSI recommended drugs and high resistance was noted for ampicillin/amoxicillin (68.1%), cotrimoxazole (75.8%) ciprofloxacin (61.5%) and ceftriaxone/cefotaxime (45.2%).

CONCLUSIONS

Shigella have become highly drug resistant to fluoroquinolones and cephalosporins. Community based studies are required to truly assess the burden of AMR in India.

Whole genome sequence analysis of Shigella from Malawi identifies fluoroquinolone resistance

Increasing antimicrobial resistance and limited alternative treatments have led to fluoroquinolone-resistant Shigella strain inclusion on the WHO global priority pathogens list. In this study we characterized multiple Shigella isolates from Malawi with whole genome sequence analysis, identifying the acquirable fluoroquinolone resistance determinant qnrS1.

Antimicrobial Resistance Surveillance in Low- and Middle-Income Countries: Progress and Challenges in Eight South Asian and Southeast Asian Countries

Antimicrobial resistance (AMR) is a serious global health threat and is predicted to cause significant health and economic impacts, particularly in low- and middle-income countries (LMICs). AMR surveillance is critical in LMICs due to high burden of bacterial infections; however, conducting AMR surveillance in resource-limited settings is constrained by poorly functioning health systems, scarce financial resources, and lack of skilled personnel. In 2015, the United Nations World Health Assembly endorsed the World Health Organization's Global Action Plan to tackle AMR; thus, several countries are striving to improve their AMR surveillance capacity, including making significant investments and establishing and expanding surveillance networks. Initial data generated from AMR surveillance networks in LMICs suggest the high prevalence of resistance, but these data exhibit several shortcomings, such as a lack of representativeness, lack of standardized laboratory practices, and underutilization of microbiology services. Despite significant progress, AMR surveillance networks in LMICs face several challenges in expansion and sustainability due to limited financial resources and technical capacity. This review summarizes the existing health infrastructure affecting the establishment of AMR surveillance programs, the burden of bacterial infections demonstrating the need for AMR surveillance, and current progress and challenges in AMR surveillance efforts in eight South and Southeast Asian countries.

Tracking Antimicrobial Resistance Determinants in Diarrheal Pathogens: A Cross-Institutional Pilot Study

Infectious diarrhea affects over four billion individuals annually and causes over a million deaths each year. Though not typically prescribed for treatment of uncomplicated diarrheal disease, antimicrobials serve as a critical part of the armamentarium used to treat severe or persistent cases. Due to widespread over- and misuse of antimicrobials, there has been an alarming increase in global resistance, for which a standardized methodology for geographic surveillance would be highly beneficial. To demonstrate that a standardized methodology could be used to provide molecular surveillance of antimicrobial resistance (AMR) genes, we initiated a pilot study to test 130 diarrheal pathogens (Campylobacter spp., Escherichia coli, Salmonella, and Shigella spp.) from the USA, Peru, Egypt, Cambodia, and Kenya for the presence/absence of over 200 AMR determinants. We detected a total of 55 different determinants conferring resistance to ten different categories of antimicrobials: genes detected in ≥ 25 samples included bla_TEM, tet(A), tet(B), mac(A), mac(B), aadA1/A2, strA, strB, sul1, sul2, qacEΔ1, cmr, and dfrA1. The number of determinants per strain ranged from none (several Campylobacter spp. strains) to sixteen, with isolates from Egypt harboring a wider variety and greater number of genes per isolate than other sites. Two samples harbored carbapenemase genes, bla_OXA-48 or bla_NDM. Genes conferring resistance to azithromycin (ere(A), mph(A)/mph(K), erm(B)), a first-line therapeutic for severe diarrhea, were detected in over 10% of all Enterobacteriaceae tested: these included >25% of the Enterobacteriaceae from Egypt and Kenya. Forty-six percent of the Egyptian Enterobacteriaceae harbored genes encoding CTX-M-1 or CTX-M-9 families of extended-spectrum β-lactamases. Overall, the data provide cross-comparable resistome information to establish regional trends in support of international surveillance activities and potentially guide geospatially informed medical care.

Oxysterols provide innate immunity to bacterial infection by mobilizing cell surface accessible cholesterol

Cholesterol 25-hydroxylase (CH25H) is an interferon-stimulated gene that converts cholesterol to the oxysterol 25-hydroxycholesterol (25HC). Circulating 25HC modulates essential immunological processes including antiviral immunity, inflammasome activation and antibody class switching; and dysregulation of CH25H may contribute to chronic inflammatory disease and cancer. Although 25HC is a potent regulator of cholesterol storage, uptake, efflux and biosynthesis, how these metabolic activities reprogram the immunological state of target cells remains poorly understood. Here, we used recently designed toxin-based biosensors that discriminate between distinct pools of plasma membrane cholesterol to elucidate how 25HC prevents Listeria monocytogenes from traversing the plasma membrane of infected host cells. The 25HC-mediated activation of acyl-CoA:cholesterol acyltransferase (ACAT) triggered rapid internalization of a biochemically defined fraction of cholesterol, termed 'accessible' cholesterol, from the plasma membrane while having little effect on cholesterol in complexes with sphingomyelin. We show that evolutionarily distinct bacterial species, L. monocytogenes and Shigella flexneri, exploit the accessible pool of cholesterol for infection and that acute mobilization of this pool by oxysterols confers immunity to these pathogens. The significance of this signal-mediated membrane remodelling pathway probably extends beyond host defence systems, as several other biologically active oxysterols also mobilize accessible cholesterol through an ACAT-dependent mechanism.

Surface-enhanced Raman spectroscopic-based aptasensor for Shigella sonnei using a dual-functional metal complex-ligated gold nanoparticles dimer

Herein, we constructed an aptamer-based sensor for the sensitive and highly specific detection of Shigella sonnei via surface enhanced Raman spectroscopy (SERS) analysis. A composite material integrated of the Raman active 4-MBA ligand of the Eu-complex and citrate-stabilized Au nanoparticles (cit-Au NPs) was synthesized and served as both active substrate and Raman reporter. Aptamers targeted to S. Sonnei was then modified onto the surface of this dual-functional material. With the introduction of S. Sonnei, aptamer bound with target with high affinity and specificity, leaving the dual-functional material onto the bacteria. The SERS intensity response showed a strong positive linear correlation (R = 0.9956) with increasing concentrations of S. sonnei (ranging from 10 to 10⁶ cfu/mL). High specificity was achieved at Shigella species (S. dysenteriae, S. flexneri, S. boydii) and other common bacteria (Salmonella typhimurium, Staphylococcus aureus and Escherichia coli). When applied in real samples, the approach showed recoveries from 92.6 to 103.8 %. The designed approach holds great potential for the construction of various aptasensors for the effective and convenient detection of different food hazards.

How genomics can be used to understand host susceptibility to enteric infection, aiding in the development of vaccines and immunotherapeutic interventions

Thanks to the modern sequencing era, the extent to which infectious disease imposes selective pressures on the worldwide human population is being revealed. This is aiding our understanding of the underlying immunological and host mechanistic defenses against these pathogens, as well as potentially assisting in the development of vaccines and therapeutics to control them. As a consequence, the workshop "How genomics can be used to understand host susceptibility to enteric infection, aiding in the development of vaccines and immunotherapeutic interventions" at the VASE 2018 meeting, aimed to discuss how genomics and related tools could be used to assist Shigella and ETEC vaccine development. The workshop featured four short presentations which highlighted how genomic applications can be used to assist in the identification of genetic patterns related to the virulence of disease, or host genetic factors that could contribute to immunity or successful vaccine responses. Following the presentations, there was an open debate with workshop attendees to discuss the best ways to utilise such genomic studies, to improve or accelerate the process of both Shigella and ETEC vaccine development. The workshop concluded by making specific recommendations on how genomic research methods could be strengthened and harmonised within the ETEC and Shigella research communities.

Characterizing Shigella species distribution and antimicrobial susceptibility to ciprofloxacin and nalidixic acid in Latin America between 2000-2015

BACKGROUND

Shigellosis is the second leading cause of diarrheal death globally. The global burden has been complicated by the emergence of Shigella strains resistant to first line antibiotic treatments such as ciprofloxacin. This study aims to describe the epidemiologic distribution of the most common Shigella species, and their antimicrobial susceptibility patterns to ciprofloxacin and nalidixic acid (NA) in Latin America.

METHODS

Laboratory data from 19 countries were obtained through the Latin American Network for Antimicrobial Resistance Surveillance (ReLAVRA) from 2000-2015. The Clinical Laboratory Standards Institute reduced susceptibility breakpoints for Enterobacteriaceae was used to interpret the disc diffusion tests for Shigella susceptibility to ciprofloxacin and NA. Negative binominal regression was used to analyze longitudinal trends of Shigella isolates antimicrobial susceptibility.

RESULTS

79,548 Shigella isolates were tested and reported between 2000-2015. The most common isolated species were S. flexneri (49%), and S. sonnei (28%). There was a steady increase in the proportion of S. sonnei isolates within the region(p<0.001). The average annual percentage increase (AAPI) in nonsusceptibility was 18.4% (p<0.001) for ciprofloxacin (baseline = 0.3); and 13.2%(p<0.001) for NA (baseline = 3). AAPI nonsusceptibility to ciprofloxacin was 13.3% for S. flexneri (p<0.04); and 39.9% for S. sonnei (p<0.001). Honduras, Dominican Republic, Venezuela, and Chile reported the highest increase in nonsusceptibility to ciprofloxacin among all Shigella isolates.

CONCLUSION

There is an increasing trend in Shigella nonsusceptibility to ciprofloxacin and NA, including among the most common shigella species, in Latin America. This rise of nonsusceptibility among Shigella species to commonly used treatments such as ciprofloxacin is alarming and threatens the control and management of this currently treatable infection. Improved data quality, collection and reporting is needed in Latin America to respond effectively to the rising trends observed. This includes the need for quality isolate level epidemiological data; molecular data, and data on antibiotic consumption and use.

Role of antigen specific T and B cells in systemic and mucosal immune responses in ETEC and Shigella infections, and their potential to serve as correlates of protection in vaccine development

The generation of robust systemic and mucosal antibody and cell-mediated immune (CMI) responses that are protective, long-lasting, and can quickly be recalled upon subsequent re-exposure to the cognate antigen is the key to the development of effective vaccine candidates. These responses, whether they represent mechanistic or non-mechanistic immunological correlates of protection, usually entail the activation of T cell memory and effector subsets (T-CMI) and induction of long-lasting memory B cells. However, for ETEC and Shigella, the precise role of these key immune cells in primary and secondary (anamnestic) immune responses remains ill-defined. A workshop to address immune correlates for ETEC and Shigella, in general, and to elucidate the mechanistic role of T-cell subsets and B-cells, both systemically and in the mucosal microenvironment, in the development of durable protective immunity against ETEC and Shigella was held at the recent 2nd Vaccines against Shigella and ETEC (VASE) conference in June 2018. This report is a summary of the presentations and the discussion that ensued at the workshop.

Molecular epidemiology and genetic characterization of Shigella in pediatric patients in Iran

Infection with Shigella is considered a major cause of morbidity and mortality in children with diarrhea in developing countries, especially in Iran. Due to the importance of country-level epidemiological data, molecular characterization of genetic determinants of Shigella spp. is a necessity. The aim of the present study was to investigate the prevalence of integron types, bla-CTX-M, bla-SHV and blaTEM β-lactamase genes of Shigella isolates in pediatric patients in Tehran, Iran. In a time period of 18 months from May 2015 to August 2017, 75 Shigella spp. were isolated from non-duplicative diarrheal stool specimens in six different hospitals in Tehran. The isolates from patients were further analyzed for their antibiotic susceptibility and extended-spectrum beta-lactamase (ESBL) production. Polymerase chain reaction was performed for amplification of the integrons (I, II, III), TEM, SHV, CTX-M15. The prevalence of S. sonnei, S. flexneri, S. dysenteriae and S. boydii were 40 (53.3%), 33 (44%), 1 (1.3%) and 1 (1.3%), respectively. The results of an antimicrobial resistance test showed that the high percentage of resistance to nalidixic acid (NA), ampicillin (AMP) and trimethoprim/sulfamethoxazole (SXT) included 38 (50.6%), 59 (81.3%) and 64 (88%) isolates, respectively. Further results revealed that 52% and 76% of Shigella isolates carried intI and intII genes, respectively. In this study, the rates of CTX-M (10.7%), SHV (28%) and TEM (21.3%) were determined, all of which were positive for blaCTX-M15. This study showed the high prevalence of multidrug resistant S. sonnei and S. flexneri. Furthermore, it highlighted the increasing integrons (intI and intII) and ESBL genes, especially blaCTX-M15, in Shigella isolates.

Alterations in the diversity and composition of mice gut microbiota by lytic or temperate gut phage treatment

Phages, the most abundant species in the mammalian gut, have numerous advantages as biocontrol agent over antibiotics. In this study, mice were orally treated with the lytic gut phage PA13076 (group B), the temperate phage BP96115 (group C), no phage (group A), or streptomycin (group D) over 31 days. At the end of the experiment, fecal microbiota diversity and composition was determined and compared using high-throughput sequencing of the V3-V4 hyper-variable region of the 16S rRNA gene and virus-like particles (VLPs) were quantified in feces. There was high diversity and richness of microbiota in the lytic and temperate gut phage-treated mice, with the lytic gut phage causing an increased alpha diversity based on the Chao1 index (p < 0.01). However, the streptomycin treatment reduced the microbiota diversity and richness (p = 0.0299). Both phage and streptomycin treatments reduced the abundance of Bacteroidetes at the phylum level (p < 0.01) and increased the abundance of the phylum Firmicutes. Interestingly, two beneficial genera, Lactobacillus and Bifidobacterium, were enhanced by treatment with the lytic and temperate gut phage. The abundance of the genus Escherichia/Shigella was higher in mice after temperate phage administration than in the control group (p < 0.01), but lower than in the streptomycin group. Moreover, streptomycin treatment increased the abundance of the genera Klebsiella and Escherichia/Shigella (p < 0.01). In terms of the gut virome, fecal VLPs did not change significantly after phage treatment. This study showed that lytic and temperate gut phage treatment modulated the composition and diversity of gut microbiota and the lytic gut phage promoted a beneficial gut ecosystem, while the temperate phage may promote conditions enabling diseases to occur.

One-pot green synthesis and structural characterisation of silver nanoparticles using aqueous leaves extract of Carissa carandas: antioxidant, anticancer and antibacterial activities

Facile green synthesis of silver nanoparticles (AgNPs) using an aqueous extract of Carissa carandas (C. carandas) leaves was studied. Fabrication of AgNPs was confirmed by the UV-visible spectroscopy which gives absorption maxima at 420 nm. C. carandas leaves are the rich source of the bioactive molecules, acts as a reducing and stabilising agent in AgNPs, confirmed by Fourier transforms infrared spectroscopy. The field emission scanning electron microscope revealed the spherical shape of biosynthesised AgNPs. A distinctive peak of silver at 3 keV was determined by energy dispersive X-ray spectroscopy. X-ray diffraction showed the facecentred cubic structure of biosynthesised AgNPs and thermal stability was confirmed by the thermogravimetric analysis. Total flavonoid and total phenolic contents were evaluated in biosynthesised AgNPs. Biosynthesised AgNPs showed free radical scavenging activities against 2, 2-diphenyl-1-picrylhydrazyl test and ferric reducing antioxidant power assay. In vitro cytotoxicity against hepatic cell lines (HUH-7) and renal cell lines (HEK-293) were also assessed. Finally, biosynthesised AgNPs were scrutinised for their antibacterial activity against methicillin-resistant Staphylococcus aureus, Shigella sonnei, Shigella boydii and Salmonella typhimurium. This study demonstrated the biofabrication of AgNPs by using C. carandas leaves extract and a potential in vitro biological application as antioxidant, anticancer and antibacterial agents.

Prevalence and antibiotic susceptibility patterns of Shigella and Salmonella among children aged below five years with Diarrhoea attending Nigist Eleni Mohammed memorial hospital, South Ethiopia

BACKGROUND

Diarrhoeal disease is the second leading cause of death among children aged below 5 years. Even though, both preventable and treatable diseases, globally there are nearly 1.7 billion cases of childhood diarrhoeal disease and responsible for killing around 525,000 children every year. Shigella and Salmonella species were the leading cause of etiologic agents for diarrhoea associated deaths. The aim of this study was to determine the prevalence and antibiotic susceptibility patterns of Shigella and Salmonella isolated from children aged below 5 years with diarrhoea attending Nigist Eleni Mohammed Memorial Hospital, Hossana, South Ethiopia.

METHODS

A cross sectional study was conducted from June 02 to September 24, 2017. Two hundred four children aged below 5 years with diarrhoea were enrolled consecutively using convenience sampling technique. Stool specimens were processed in accordance with the standard bacteriological methods and antibiotic susceptibility pattern of the isolates was determined using disc diffusion method. Data were analyzed using SPSS version 20.

RESULTS

Out of the 204 children aged below 5 years with diarrhoeal disease 19/204 (9.3%, [95%CI, 5.7-13.7%]) of them were positive for bacterial growth, of which 17/204(8.3%) were Shigella species and 2/204(1%) were Salmonella species. Both Shigella and Salmonella isolates were 100% susceptible to norfloxacin, nalidixic acid and kanamycin. However, isolates of Shigella showed 100, 76.5 and 64.7% resistance to ampicillin, gentamicin and cotrimoxazole respectively while Salmonella species were highly resistant to ampicillin and gentamicin (100% each).

CONCLUSIONS

Salmonella and Shigella species is prevalent in the current study area. Among the tested antibiotics, norfloxacin, nalidixic acid and kanamycin were found to be most effective for both isolates. Both species are developing resistance to the commonly prescribed antibiotic. Therefore, culture based bacterial species identification and antimicrobial susceptibility testing services are strongly recommended to avoid empirical treatment in the study area.

Antimicrobial resistance among Shigella in New Zealand

AIM

We undertook a national survey to provide current information on antimicrobial resistance among Shigella isolated in New Zealand.

METHODS

Diagnostic laboratories are requested to refer all Shigella isolates to the Institute of Environmental Science and Research (ESR) for epidemiological typing as part of the national surveillance of shigellosis. The antimicrobial susceptibility of 263 non-duplicate Shigella isolates referred to ESR in 2015 and 2016 was tested.

RESULTS

The 263 Shigella comprised 141 (53.6%) S. sonnei, 113 (43.0%) S. flexneri, 7 (2.7%) S. boydii and 2 (0.8%) S. dysenteriae. Among the 141 S. sonnei, the majority were either biotype g (90) or biotype a (50). Rates of resistance to the two currently recommended first-line antibiotics, co-trimoxazole and fluoroquinolones, were relatively high at 56.7% and 22.8%, respectively. Azithromycin is considered a second-line treatment option, but 11.0% of Shigella were categorised as having a non-wildtype (NWT) azithromycin phenotype (ie, having some mechanism of azithromycin resistance although not necessarily clinically resistant). There were several significant differences in resistance between the two most prevalent S. sonnei biotypes, with resistance being significantly more prevalent among biotype g isolates. Shigella from patients who had not travelled overseas were significantly more likely to be azithromycin NWT than isolates from patients who had recently travelled (20.7 vs 5.6%). Azithromycin NWT was more prevalent among Shigella from males than females (13.9 vs 7.7%).

CONCLUSIONS

These results suggest there is an immediate need to revise the currently recommended first-line treatment for shigellosis, especially when treatment is given on an empirical basis. Equally concerning is the fact that resistance to the second-line antibiotic for shigellosis, azithromycin, appears to be emerging in New Zealand. As diagnostic laboratories increase their use of culture-independent testing, it is recommended that they should continue to culture specimens from all shigellosis cases so that isolates are available for susceptibility testing and epidemiological typing.

Dominant serotype distribution and antimicrobial resistance profile of Shigella spp. in Xinjiang, China

Shigella represents one of the major diarrhea-inducing pathogens threatening public health, but its prevalence and antimicrobial resistance profile in Xinjiang Uygur Autonomous region, China, remains unclear. We conducted comprehensive investigation of Shigella serotype distribution and antimicrobial resistance pattern in Xinjiang, identifying 458 Shigella isolates between 2008 to 2014. Shigella flexneri was identified as predominant species, and several S. flexneri serotypes were isolated, including atypical serotypes 1c, 2c, and 4s. Dominant S. flexneri serotypes were 2a, 1b, 2b, and Xv, different from those generally dominant in China. A hybrid serotype pattern was observed, which included the major Chinese serotypes (2a, Xv) and those predominant in Pakistan (1b, 2b). Shigella sonnei was shown to have a lower frequency compared with that generally observed in China, but an increasing trend of infections associated with this pathogen was observed. Furthermore, a high frequency of drug resistance and different Shigella antimicrobial resistance patterns were demonstrated as well, including very severe resistance phenotypes, such as multidrug resistance and resistance to frontline antibiotics. Seventy-five cephalosporin-resistant Shigella isolates were frequently identified with the resistance determinants that can undergo horizontal transfer, such as bla_OXA, bla_TEM, bla_CTX-M, and integrons, facilitating the development of cephalosporin resistance among Shigella subtypes. Additionally, genetic analyses demonstrated that all 86 quinolone-resistant S. flexneri isolates possess 3–4 mutation sites in quinolone resistance-determining regions, primarily contributing to their resistance to quinolone. However, S. sonnei isolates were not shown to be quinolone resistant. Co-resistance to cephalosporins and quinolones was detected in 17 S. flexneri isolates, and these isolates were additionally multidrug resistant and carried β-lactamase genes and quinolone-resistance determinants. As is demonstrated in this study, dominant serotypes of Shigella were distributed in unique trend with dangerous drug resistance patterns. Novel strategies are urgently required to prevent the development of drug resistance among diarrhea-inducing pathogens.

Comparative Review of Antimicrobial Resistance in Humans and Nonhuman Primates

Antimicrobial resistance (AMR) presents serious threats to human and animal health. Although AMR of pathogens is often evaluated independently between humans and animals, comparative analysis of AMR between humans and animals is necessary for zoonotic pathogens. Major surveillance systems monitor AMR of zoonotic pathogens in humans and food animals, but comprehensive AMR data in veterinary medicine is not diligently monitored for most animal species with which humans commonly contact, including NHP. The objective of this review is to provide a complete report of the prevalences of AMR among zoonotic bacteria that present the greatest threats to NHP, occupational, and public health. High prevalences of AMR exist among Shigella, Campylobacter, and Yersinia, including resistance to antimicrobials important to public health, such as macrolides. Despite improvements in regulations, standards, policies, practices, and zoonotic awareness, occupational exposures to and illnesses due to zoonotic pathogens continue to be reported and, given the documented prevalences of AMR, constitute an occupational and public health risk. However, published literature is sparse, thus indicating the need for veterinarians to proactively monitor AMR in dangerous zoonotic bacteria, to enable veterinarians to make more informed decisions to maximize antimicrobial therapy and minimize occupational risk.

Increasing Antibiotic Resistance in Shigella spp. from Infected New York City Residents, New York, USA

Approximately 20% of Shigella isolates tested in New York City, New York, USA, during 2013–2015 displayed decreased azithromycin susceptibility. Case-patients were older and more frequently male and HIV infected than those with azithromycin-susceptible Shigella infection; 90% identified as men who have sex with men. Clinical interpretation guidelines for azithromycin resistance and outcome studies are needed.

Multidrug-Resistant Shigella Infections in Patients with Diarrhea, Cambodia, 2014-2015

We observed multidrug resistance in 10 (91%) of 11 Shigella isolates from a diarrheal surveillance study in Cambodia. One isolate was resistant to fluoroquinolones and cephalosporins and showed decreased susceptibility to azithromycin. We found mutations in gyrA, parC, β-lactamase, and mphA genes. Multidrug resistance increases concern about shigellosis treatment options.

No Clinical Benefit of Empirical Antimicrobial Therapy for Pediatric Diarrhea in a High-Usage, High-Resistance Setting

Background

Pediatric diarrheal disease presents a major public health burden in low- to middle-income countries. The clinical benefits of empirical antimicrobial treatment for diarrhea are unclear in settings that lack reliable diagnostics and have high antimicrobial resistance (AMR).

Methods

We conducted a prospective multicenter cross-sectional study of pediatric patients hospitalized with diarrhea containing blood and/or mucus in Ho Chi Minh City, Vietnam. Clinical parameters, including disease outcome and treatment, were measured. Shigella, nontyphoidal Salmonella (NTS), and Campylobacter were isolated from fecal samples, and their antimicrobial susceptibility profiles were determined. Statistical analyses, comprising log-rank tests and accelerated failure time models, were performed to assess the effect of antimicrobials on disease outcome.

Results

Among 3166 recruited participants (median age 10 months; interquartile range, 6.5-16.7 months), one-third (1096 of 3166) had bloody diarrhea, and 25% (793 of 3166) were culture positive for Shigella, NTS, or Campylobacter. More than 85% of patients (2697 of 3166) were treated with antimicrobials; fluoroquinolones were the most commonly administered antimicrobials. AMR was highly prevalent among the isolated bacteria, including resistance against fluoroquinolones and third-generation cephalosporins. Antimicrobial treatment and multidrug resistance status of the infecting pathogens were found to have no significant effect on outcome. Antimicrobial treatment was significantly associated with an increase in the duration of hospitalization with particular groups of diarrheal diseases.

Conclusions

In a setting with high antimicrobial usage and high AMR, our results imply a lack of clinical benefit for treating diarrhea with antimicrobials; adequately powered randomized controlled trials are required to assess the role of antimicrobials for diarrhea.

Shigella Antimicrobial Drug Resistance Mechanisms, 2004-2014

To determine antimicrobial drug resistance mechanisms of Shigella spp., we analyzed 344 isolates collected in Switzerland during 2004–2014. Overall, 78.5% of isolates were multidrug resistant; 10.5% were ciprofloxacin resistant; and 2% harbored mph(A), a plasmid-mediated gene that confers reduced susceptibility to azithromycin, a last-resort antimicrobial agent for shigellosis.

The pathogenic detection for 126 children with diarrhea and drug sensitivity tests

OBJECTIVE

To investigate the cause of infective diarrhea in children, special distribution of the infection and the drug sensitivity.

PATIENTS AND METHODS

We carried out pathogenic detection and drug sensitivity tests for one hundred and twenty-six children with diarrhea, including 67 children in infant group (0-<1 year) and 59 children in child group (1-5 years).

RESULTS

Fat particles and starch particles were seen in most stool samples under microscope; 42 kinds of pathogenic bacteria were obtained from 126 stool samples, including 10 Diarrheagenic E. coli (8 Enteropathogenic E. coli and Enteroinvasive E. coli); there were found 53 positive samples in the detection of anti-rotavirus antibody in 126 stool samples; in the drug sensitivity tests for major pathogenic bacteria, Staphylococcus aureus, Shigella, Salmonella and Diarrheagenic E. coli were highly sensitive.

CONCLUSIONS

The abuse of antimicrobial agents may result in intestinal disorders, leading to aggravation in diarrhea and antimicrobial agents based on drug sensitivity tests may be served as fundamental treatment of diarrhea for children.

Surveillance for Travel and Domestically Acquired Multidrug-Resistant Human Shigella Infections-Pennsylvania, 2006-2014

Shigellosis is a leading cause of enteric infections in the United States. We compared antimicrobial resistance in Shigella infections related to overseas travel (travel-associated) and in those acquired domestically by analyzing antimicrobial resistance patterns, geographic distributions, and pulsed-field gel electrophoresis (PFGE) patterns. We tested samples (n = 204) from a collection of isolates recovered from patients in Pennsylvania between 2006 and 2014. Isolates were grouped into travel- and non-travel-associated categories. Eighty-one (79.4%) of the Shigella isolates acquired during international travel were resistant to multiple antibiotics compared to 53 (52.1%) of the infections transmitted in domestic settings. A majority (79.4%) of isolates associated with international travel demonstrated resistance to aminoglycosides and tetracyclines, whereas 47 (46.1%) of the infections acquired domestically were resistant to tetracycline. Almost all isolates (92.2%) transmitted in domestic settings were resistant to aminoglycosides, and 5 isolates from adult male patients were resistant to azithromycin, a drug often used for empiric treatment of severe shigellosis. Twenty (19.6%) isolates associated with illnesses acquired during overseas travel in 4 countries were resistant to quinolones. One S. sonnei PFGE pattern was traced to a multidrug-resistant isolate acquired overseas that had caused a multistate outbreak of shigellosis, suggesting global dissemination of a drug-resistant species. Resistance to certain drugs-for example, tetracycline-increased in both overseas- and domestic-acquired infections during the study period. The prevalence of resistance to macrolides (azithromycin) and third-generation cephalosporins (ceftriaxone) was less than 1%; however, efforts to better monitor changes in drug resistance over time combined with increased antimicrobial stewardship are essential at the local, national, and global levels.

Moderate dietary protein restriction alters the composition of gut microbiota and improves ileal barrier function in adult pig model

This study was conducted to investigate impacts of dietary protein levels on gut bacterial community and gut barrier. The intestinal microbiota of finishing pigs, fed with 16%, 13% and 10% crude protein (CP) in diets, respectively, were investigated using Illumina MiSeq sequencing. The ileal bacterial richness tended to decrease when the dietary protein concentration reduced from 16% to 10%. The proportion of Clostridium_sensu_stricto_1 in ileum significantly decreased, whereas Escherichia-Shigella increased with reduction of protein concentration. In colon, the proportion of Clostridium_sensu_stricto_1 and Turicibacter increased, while the proportion of RC9_gut_group significantly decreased with the dietary protein reduction. Notably, the proportion of Peptostreptococcaceae was higher in both ileum and colon of 13% CP group. As for metabolites, the intestinal concentrations of SCFAs and biogenic amines decreased with the dietary protein reduction. The 10% CP dietary treatment damaged ileal mucosal morphology, and decreased the expression of biomarks of intestinal cells (Lgr5 and Bmi1), whereas the expression of tight junction proteins (occludin and claudin) in 13% CP group were higher than the other two groups. In conclusion, moderate dietary protein restriction (13% CP) could alter the bacterial community and metabolites, promote colonization of beneficial bacteria in both ileum and colon, and improve gut barrier function.

[Changes of resistant phenotype and CRISPR/Cas system of four Shigella strains passaged for 90 times without antibiotics]

Objective: To explore the stability of resistant phenotypes and changes of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) gene system on four Shigella strains in the absence of antibiotics. Methods: Four clinical isolated Shigella strains that resistant to different antibiotics were consecutive passaged for 90 times without antibiotics. Agar dilution method was used to determine the minimum inhibitory concentration of Shigella strains. After sequence analysis with PCR, CRISPR Finder and Clustal X 2.1 were applied to identify the changes of CRISPR loci in the Shigella strains. Results: After the consecutive transfer of 90 generations, sensitivity to certain antibiotics of four Shigella strains with different drug resistant spectrums increased. Mel-sf1998024/zz resistance to ampicillin, cephalexin, cefotaxime, chloramphenicol decreased, mel-s2014026/sx resistance to norfloxacin, trimethoprim decreased, mel-sf2004004/sx drug resistance to ampicillin, cefuroxime, cefotaxime, chloramphenicol, trimethoprim decreased and mel-sf2013004/bj resistance to chloramphenicol decreased. The spacer of which matched gene codes Cas and its upstream repeat in 3'end of CRISPR3 got lost in mel-sf1998024/zz and mel-sf2013004/bj. Conclusions:Shigella strains could reduce or lose their resistance to some antibiotics after consecutive transfers, without the interference of antibiotics. CRISPR3 locus had dynamic spacers in Shigella strains while CRISPR3 locus and cas genes might have been co-evolved.

[Role of CRISPR/Cas systems in drugresistance and virulence and the effect of IS600 on the expression of cse2 in Shigella]

OBJECTIVE

To analyze the relationship between CRISPR/Cas system and drug-resistance, virulence. To investigate the effect of IS600 on the expression of CRISPR associated gene cse2 in Shigella.

METHODS

CRISPR loci, CRISPR associated gene cse2, drug-resistant genes and virulent genes were detected by PCR in 33 Shigella strains; Trypan Blue counting test was used to detect bacterial virulence; Real-time PCR was used to detect relative mRNA expression of cse2; susceptibilities of Shigella strains were tested by agar diffusion method. Furthermore, we analyzed the relationship between CRISPR loci and drug-resistant genes, virulent genes. The effect of the IS600 on the expression of CRISPR associated gene cse2 was investigated.

RESULTS

The mortality of Hela cells infected by Shigella with CRISPR1 loci was significantly lower (P<0.05) than those infected by Shigella without CRISPR1. The mRNA expression level of cse2 in group with IS600 was significantly (P<0.05) lower than that in group without IS600.

CONCLUSIONS

CRISPR loci were widely present in Shigella. Shigella without CRISPR1 has a higher pathogenicity. Due to the insertion of IS600, the mRNA expression level of cse2 was decreased in Shigella.

FABRICATION AND EVALUATION OF SMART NANOCRYSTALS OF ARTEMISININ FOR ANTIMALARIAL AND ANTIBACTERIAL EFFICACY

BACKGROUND

Nanocrystals have the potential to substantially increase dissolution rate, solubility with subsequent enhanced bioavailability via the oral route of a range of poor water soluble drugs. Regardless of other issues, scale up of the batch size is the main issue associated with bottom up approach.

MATERIAL AND METHODS

Smart nanocrystals of artemisinin (ARM) was produced relatively at large batch sizes (100, 200, 300 and 400ml) compared to our previously reported study by (Shah, et al., 2016). ARM nanosuspensions/nanocrystals were characterised using zeta sizer, SEM, TEM, DSC, PXRD and RP-HPLC. The nanosuspensions were finally subjected to in vitro antimalarial and antimicrobial activity.

RESULTS

The average particle size (PS) for 400 ml batches was 126.5 ±1.02 nm, and the polydispersity index (PI) was 0.194 ± 0.04. The saturation solubility of the ARM nanocrystals was substantially increased to (725.4± 2.0 μg/ml) compared to the raw ARM in water 177.4± 1.3 μg/ml and stabilizer solution (385.3± 2.0 μg/ml). The IC50 value of ARM nanosuspension against P. vivax was 65 and 21 folds lower than micronized 19.5 ng/mL and unprocessed drug (6.4 ng/mL) respectively. The ARM nanosuspension was found highly effective compared to unprocessed drug against all the tested microorganism except E. coli, Shigella and C. albican.

CONCLUSION

The simple precipitation-ultrasonication approach was efficiently employed for fabrication of ARM nanosuspension to scale up the batch size. Similarly, the solubility, antimalarial potential and antimicrobial efficacy of ARM in the form of nanosuspension were significantly enhanced. Findings from this study can persuade research interest for further comprehensive studies using animals model.

Prevalence, antimicrobial susceptibility patterns and associated risk factors of Shigella and Salmonella among food handlers in Arba Minch University, South Ethiopia

BACKGROUND

The availability of safe food improves health of the people that contributes to productivity and provides an effective platform for development and poverty alleviation. On the other hand, unsafe food handling and processing can serve as a vehicle for the transmission of a variety of disease causing agents. The risk of food getting contaminated depends largely on the health status of the food handlers, their personal hygiene, knowledge and practice of food hygiene. Food borne diseases are therefore a public health problem in developed and developing countries which is also true for Ethiopia. Hence, the aim of this study was to determine prevalence, antimicrobial susceptibility patterns and associated risk factors of Shigella and Salmonella among food handlers in Arba Minch University, South Ethiopia.

METHODS

A cross sectional study was conducted among food handlers in Arba Minch University students' cafeteria from April- June, 2015. Structured questionnaire was used to collect socio demographic data and associated risk factors. Stool sample was collected and examined for pathogens following standard procedures. Biochemical tests were done to identify the species of pathogens and sensitivity test was done using Kirby- Baur disk diffusion technique.

RESULTS

A total of 376 food handlers were enrolled in the study with the response rate of 100% for data collected by questionnaire. About 7.4% were aged less than 20 years with majority (63.3%) lay in the working age group of 21-35 years. However, a total of 345 food handlers participated for stool examination of whom, stool cultures revealed 6.9% of Salmonella and 3% Shigella isolates. Finger nail status (AOR=0.033), hand washing practice after toilet (AOR= 0.006) and touching food with bare hands (AOR= p < 0.001) were independent predictors of infectious enteric diseases among the food handlers. All isolated pathogens were resistant to amoxicillin (100%), followed by clarithromycin (41%) and amoxicillin-clavulanic acid (35%).

CONCLUSION

The present study showed high prevalence of enteropathogens among the study participants. The study also revealed poor personal hygiene like poor practice of hand washing. Therefore, pre placement, in service training on personal and food hygiene should be provided to all food handlers with regular sanitary inspection to improve adherence of food handlers to personal hygiene and food safety practices.

Evaluation of antimicrobial resistance among Salmonella and Shigella isolates in the University Hospital "St. George," Plovdiv, Bulgaria

The aim of this work is to study the epidemiology and antimicrobial resistance to the most commonly used antibiotics for the treatment of acute gastroenteritis caused by Salmonella and Shigella at the largest Bulgarian hospital-University Hospital "St. George," Plovdiv-for the period 2009-2013. Two hundred ninety strains were in vitro tested for resistance to 15 antimicrobial agents. The presence of extended-spectrum beta-lactamases (ESBLs) was demonstrated by a variety of specialized tests. For comparison, a collection of 28 strains submitted by the National Reference Laboratory (NRL) "Enteric Infections" at the National Center of Infectious and Parasitic Diseases (NCIPD), Sofia, was also tested for the production of ESBLs. In isolates, phenotypically demonstrated as ESBL producers, polymerase chain reaction (PCR) detection of the genes bla-CTX-M, bla-SHV, and bla-TEM was performed. Among the 290 tested isolates, only two- Salmonella serotype Livingstone and Shigella flexneri-were phenotypically proven to be ESBL producers. Only 4 strains from the collection of 28, submitted from the NRL "Intestinal Infections" in NCIPD, Sofia, were phenotypically confirmed as ESBL producers. The presence of the bla-CTX-M gene was detected in all of the tested strains (4 from NRL, NCIPD, Sofia, and 2 from the University Hospital St. George, Plovdiv), the bla-SHV gene only in strain S. Livingstone from Plovdiv, and the bla-TEM gene in two from Sofia and one (again S. Livingstone) from Plovdiv. In conclusion, Salmonella and Shigella isolates from patients hospitalized at the University Hospital St. George, Plovdiv, with acute gastroenteritis demonstrate good susceptibility to the most commonly used antibiotic agents, including azithromycin.

The importance of integrons for development and propagation of resistance in Shigella: the case of Latin America

In Latin America, the disease burden of shigellosis is found to coexist with the rapid and rampant spread of resistance to commonly used antibiotics. The molecular basis of antibiotic resistance lies within genetic elements such as plasmids, transposons, integrons, genomic islands, etc., which are found in the bacterial genome. Integrons are known to acquire, exchange, and express genes within gene cassettes and it is hypothesized that they play a significant role in the transmission of multidrug resistance genes in several Gram-negative bacteria including Shigella. A few studies have described antibiotic resistance genes and integrons among multidrug resistant Shigella isolates found in Latin America. For example, in Brazil, Bolivia, Chile, Costa Rica and Peru, class 1 and class 2 integrons have been detected among multidrug resistant strains of Shigella; this phenomenon is more frequently observed in S. flexneri isolates that are resistant to trimethoprim, sulfamethoxazole, streptomycin, ampicillin, chloramphenicol, and tetracycline. The gene cassette sul2, which is frequently detected in Shigella strains resistant to the sulfonamides, suggests that the sulfonamide-resistant phenotype can be explained by the presence of the sul2 genes independent of the integron class detected. It is to be noted that sul3 was negative in all isolates analyzed in these studies. The high frequency of sulfonamide (as encoded by sul2) and trimethoprim resistance is likely to be a result of the recurrent use of trimethoprim sulfamethoxazole as a popular regimen for the treatment of shigellosis. The observed resistance profiles of Shigella strains confirm that ampicillin and trimethoprim-sulfamethoxazole are ineffective as therapeutic options. In-depth information regarding antibiotic resistance mechanism in this pathogen is needed in order to develop suitable intervention strategies. There is a pressing need for regional and local antimicrobial resistance profiling of Shigella to be included as a part of the public health strategy.

Elevated Risk for Antimicrobial Drug-Resistant Shigella Infection among Men Who Have Sex with Men, United States, 2011-2015

Shigella spp. cause ≈500,000 illnesses in the United States annually, and resistance to ciprofloxacin, ceftriaxone, and azithromycin is emerging. We investigated associations between transmission route and antimicrobial resistance among US shigellosis clusters reported during 2011-2015. Of 32 clusters, 9 were caused by shigellae resistant to ciprofloxacin (3 clusters), ceftriaxone (2 clusters), or azithromycin (7 clusters); 3 clusters were resistant to >1 of these drugs. We observed resistance to any of these drugs in all 7 clusters among men who have sex with men (MSM) but in only 2 of the other 25 clusters (p<0.001). Azithromycin resistance was more common among MSM-associated clusters than other clusters (86% vs. 4% of clusters; p<0.001). For adults with suspected shigellosis, clinicians should culture feces; obtain sex histories; discuss shigellosis prevention; and choose treatment, when needed, according to antimicrobial drug susceptibility. Public health interviews for enteric illnesses should encompass sex practices; health messaging for MSM must include shigellosis prevention.

Multi drug resistance and Extended Spectrum Beta Lactamases in clinical isolates of Shigella: A study from New Delhi, India

BACKGROUND

Shigella is an important cause of gastroenteritis in local Indian population, as well as of traveler's diarrhea in the international visitors to India. These patients often require appropriate antimicrobial therapy; however, rapid development of antimicrobial resistance poses a major hurdle in achieving this goal.

METHOD

A prospective study was conducted during 2009-12 in New Delhi, India, including 6339 stool samples from gastroenteritis patients. 121 Shigella strains were identified on the basis of colony morphology, biochemical reactions, serotyping and ipaH gene based PCR. Antimicrobial susceptibility testing by disc diffusion, MIC determination by Vitek(®) 2 and phenotypic tests for ESBL/AmpC production were done.

RESULTS

Nineteen percent strains (23/121) were found to be resistant to third generation cephalosporins and all were phenotypically confirmed to be ESBL producers; one strain was positive for AmpC. ESBL producing strains were also found to be significantly more resistant (p < 0.05) to several other antimicrobials agents in comparison to ESBL non-producers, [ampicillin (100% vs. 62.2%), ampicillin/sulbactam (100% vs. 30.6%), cotrimoxazole (100% vs. 77.6%), ciprofloxacin (87.0% vs. 49.0%), ofloxacin (87.0% vs. 52.0%) and gentamicin (30.4% vs. 7.1%)]. Multidrug resistance was seen in 76% strains.

CONCLUSIONS

Inappropriate use of antimicrobial agents puts high selection pressure on the higher-end antibiotics. Multi-drug resistance and high rates of ESBL production by Shigella is a matter of concern for the local population as well as international travelers. Therefore, better national level antimicrobial management programs are the priority needs.

CTX-M extended-spectrum β-lactamase-producing Klebsiella spp, Salmonella spp, Shigella spp and Escherichia coli isolates in Iranian hospitals

This study was conducted in Iran in order to assess the distribution of CTX-M type ESBLs producing Enterobacteriaceae. From January 2012 to December 2013, totally 198 E. coli, 139 Klebsiella spp, 54 Salmonella spp and 52 Shigella spp from seven hospitals of six provinces in Iran were screened for resistance to extended-spectrum cephalosporins. After identification and susceptibility testing, isolates presenting multiple-drug resistance (MDR) were evaluated for ESBL production by the disk combination method and by Etest using (cefotaxime and cefotaxime plus clavulanic acid). All isolates were also screened for bla_CTX-M using conventional PCR. A total of 42.92%, 33.81%, 14.81% and 7.69% of the E. coli, Klebsiella spp, Salmonella spp and Shigella spp isolates were MDR, respectively. The presence of CTX-M enzyme among ESBL-producing isolates was 85.18%, 77.7%, 50%, and 66.7%, in E. coli, Klebsiella spp, Salmonella spp and Shigella spp respectively. The overall presence of CTX-M genes in Enterobacteriaceae was 15.4% and among the resistant isolates was 47.6%. This study indicated that resistance to β-lactams mediated by CTX-M enzymes in Iran had similar pattern as in other parts of the world. In order to control the spread of resistance, comprehensive studies and programs are needed.

Travel Destinations and Sexual Behavior as Indicators of Antibiotic Resistant Shigella Strains--Victoria, Australia

BACKGROUND

Knowledge of relationships between antibiotic susceptibility of Shigella isolates and travel destination or other risk factors can assist clinicians in determining appropriate antibiotic therapy prior to susceptibility testing. We describe relationships between resistance patterns and risk factors for acquisition in Shigella isolates using routinely collected data for notified cases of shigellosis between 2008 and 2012 in Victoria, Australia.

METHODS

We included all shigellosis patients notified during the study period, where Shigella isolates were tested for antimicrobial sensitivity using Clinical and Laboratory Standards Institute breakpoints. Cases were interviewed to collect data on risk factors, including recent travel. Data were analyzed using Stata 13.1 to examine associations between risk factors and resistant strains.

RESULTS

Of the 500 cases of shigellosis, 249 were associated with overseas travel and 210 were locally acquired. Forty-six of 51 isolates of Indian origin displayed decreased susceptibility or resistance to ciprofloxacin. All isolates of Indonesian origin were susceptible to ciprofloxacin. Twenty-six travel-related isolates were resistant to all tested oral antimicrobials. Male-to-male sexual contact was the primary risk factor for 80% (120/150) of locally acquired infections among adult males, characterized by distinct periodic Shigella sonnei outbreaks.

CONCLUSIONS

Clinicians should consider travel destination as a marker for resistance to common antimicrobials in returning travelers, where severe disease requires empirical treatment prior to receipt of individual sensitivity testing results. Repeated outbreaks of locally acquired shigellosis among men who have sex with men highlight the importance of prevention and control measures in this high-risk group.

Changing patterns of drug-resistant Shigella isolates in egypt

BACKGROUND

The emergence of multidrug resistance (MDR) is a serious problem in treating shigellosis. There are limited existing data examining the change in the antimicrobial resistance profile of Shigella in Egypt. We previously reported that 58% of the Shigella isolates in Egypt were resistant to at least one member of the three different antimicrobial groups. This study was performed to determine the antimicrobial resistance profile of Shigella, determine their possible mechanisms of resistance, and compare their resistance profile to those reported 20 years ago.

PATIENTS AND METHODS

Stool samples were collected from 500 subjects and processed for the isolation and identification of Shigella. The susceptibility of the isolates to 11 different antimicrobials was determined using the disc diffusion method.

RESULTS

Of 500 stool cultures, 24 (4.8%) samples were positive for Shigella. There was a high percentage of resistance to ampicillin (88%), tetracycline (83%), and sulfamethoxazole-trimethoprim (75%). Also, there was a moderate percentage of resistance to chloramphenicol (46%), streptomycin (42%), ceftazidime (33%), and cefotaxime (25%). A lower percentage of resistance was recorded for amikacin, nalidixic acid (17% each), and ofloxacin (7%), while no resistance was found to ciprofloxacin (0%). Twenty-one of the isolates (88%) were resistant to at least three different antimicrobial groups (indicating MDR). The average number of antimicrobial agents to which the Shigella isolates were resistant was 4.3±1.4, while it was 3.4±1.5 in the same locality in 1994.

CONCLUSION

These data demonstrate that there is a marked increase in MDR and change in the resistance patterns of Shigella over the past 20 years.

Antimicrobial susceptibility testing of bacteria that cause gastroenteritis

Gastroenteritis due to enteric pathogens is generally a self-limiting disease for which antimicrobial treatment is not required. However, treatment should be considered for cases of severe or prolonged diarrhea, extraintestinal isolation of bacteria, or diarrhea in immunocompromised hosts, the elderly, and infants. Various resistance trends and current issues concerning antimicrobial susceptibility testing of enteric pathogens are reviewed in this article, including Campylobacter, Salmonella, Shigella, Vibrio, Aeromonas, Plesiomonas, and Clostridium difficile. Updated interpretive criteria from breakpoint-setting organizations are reviewed, along with explanations for recent changes in antimicrobial breakpoints.

Shigella spp. with reduced azithromycin susceptibility, Quebec, Canada, 2012-2013

During 2012-2013 in Montreal, Canada, 4 locally acquired Shigella spp. pulse types with the mph(A) gene and reduced susceptibility to azithromycin were identified from 9 men who have sex with men, 7 of whom were HIV infected. Counseling about prevention of enteric sexually transmitted infections might help slow transmission of these organisms.

Sulfonamide-resistant bacteria and their resistance genes in soils fertilized with manures from Jiangsu Province, Southeastern China

Antibiotic-resistant bacteria and genes are recognized as new environmental pollutants that warrant special concern. There were few reports on veterinary antibiotic-resistant bacteria and genes in China. This work systematically analyzed the prevalence and distribution of sulfonamide resistance genes in soils from the environments around poultry and livestock farms in Jiangsu Province, Southeastern China. The results showed that the animal manure application made the spread and abundance of antibiotic resistance genes (ARGs) increasingly in the soil. The frequency of sulfonamide resistance genes was sul1 > sul2 > sul3 in pig-manured soil DNA and sul2 > sul1 > sul3 in chicken-manured soil DNA. Further analysis suggested that the frequency distribution of the sul genes in the genomic DNA and plasmids of the SR isolates from manured soil was sul2 > sul1 > sul3 overall (p<0.05). The combination of sul1 and sul2 was the most frequent, and the co-existence of sul1 and sul3 was not found either in the genomic DNA or plasmids. The sample type, animal type and sampling time can influence the prevalence and distribution pattern of sulfonamide resistance genes. The present study also indicated that Bacillus, Pseudomonas and Shigella were the most prevalent sul-positive genera in the soil, suggesting a potential human health risk. The above results could be important in the evaluation of antibiotic-resistant bacteria and genes from manure as sources of agricultural soil pollution; the results also demonstrate the necessity and urgency of the regulation and supervision of veterinary antibiotics in China.

Stable Silver Nanoparticles Synthesis by Citrus Sinensis (Orange) and Assessing Activity Against Food Poisoning Microbes

Silver nanoparticles are considered as good antimicrobial agent. AgNPs were synthesized by mixing silver nitrate solution with citrus sinesis extract for 2 h at 37 °C and analyzed by UV-visible spectra, SEM, XRD, and FTIR. AgNPs were tested against B. subtilis, Shigella, S. aureus, and E. coli. Minimum inhibitory concentration of AgNPs was 20 µg/mL for B. subtilis and Shigella and 30 µg/mL for S. aureus and E. coli. Antibiofilm activity (80% to 90%) was observed at 25 µg/mL. AgNPs were stable for five months with sustained antimicrobial activity. Biosynthesized AgNPs can be used to inhibit food poisoning microbial growth.

Clinical characteristics, etiology and antimicrobial susceptibility among overweight and obese individuals with diarrhea: observed at a large diarrheal disease hospital, Bangladesh

BACKGROUND

The present study aimed to determine the clinical characteristics and etiology of overweight and obese (OO) individuals with diarrhea attending an urban Dhaka Hospital, International Centre for Diarrheal Disease Research (icddr,b), Bangladesh.

METHODS

Total of 508 under-5 children, 96 individuals of 5-19 years and 1331 of >19 years were identified as OO from the Diarrheal Disease Surveillance System (DDSS) between 1993-2011. Two comparison groups such as well-nourished and malnourished individuals from respective age stratums were selected.

RESULTS

Isolation rate of rotavirus was higher among OO under-5 children compared to malnourished group (46% vs. 28%). Rotavirus infection among OO individuals aged 5-19 years (9% vs. 3%) (9% vs. 3%) and >19 years (6% vs. 4%) (6% vs. 3%) was higher compared to well-nourished and malnourished children. Conversely, Vibrio cholerae was lower among all OO age groups compared to well-nourished and malnourished ones. Shigella (4% vs. 6%) (4% vs. 8%), and Campylobacter (3% vs. 5%) (3% vs. 5%) were lower only among OO in >19 years individuals compared to their counterparts of the same age stratum. Salmonella was similarly isolated in all age strata and nutritional groups. In multinomial logistic regression among under-5 children, significant association was observed only with use of antimicrobials at home [OR-1.97] and duration of hospital stay [OR-0.68]. For individuals aged 5-19 years, use of antimicrobials at home (OR-1.83), some or severe dehydration (OR-3.12), having received intravenous saline (OR-0.46) and rotavirus diarrhea (OR-2.96) were found to be associated with OO respectively. Moreover, significant associations were also found for duration of diarrhea before coming to hospital (>24 hours) (OR-1.24), Shigella (OR-0.46), and Campylobacter (OR-0.58) among >19 years OO individuals along with other associated co-variates in 5-19 years group (all p<0.05).

CONCLUSION AND SIGNIFICANCE

Higher proportion of OO were infected with rotavirus and a greater proportion of them used antimicrobials before coming to the hospital.

Antimicrobial resistance in Shigella spp. causing traveller's diarrhoea (1995-2010): a retrospective analysis

BACKGROUND

Shigellosis is a global human health problem causing an important morbidity among travellers returning from tropical areas. This study was aimed to describe the evolution of antimicrobial resistance profile in Shigella spp. isolated between the years 1995-2010 in patients with traveller's diarrhoea (TD) returning from tropical areas.

METHODS

The levels of antimicrobial resistance were tested in a total of 191 Shigella spp. isolated during the period from 1995 to 2010.

RESULTS

A decrease of cases of diarrhoea caused by Shigella has been observed in recent years. A wide spectrum of antibiotic resistance was observed among Shigella spp. These isolates showed high levels of resistance to tetracycline (84%), co-trimoxazole (75.5%), and ampicillin (45.5%). The resistance was low to ciprofloxacin (2.1%), azithromycin (3.9%) and furazolidone (8.4%). According to the period, in the case of ampicillin, amoxicillin plus clavulanic acid, chloramphenicol, values of resistance were significantly decreasing from 1995-2000 to 2001-2010, (62.5% vs. 28.4%, 19.8% vs. 6.6%, 23.4 vs. 10.4%, respectively). Meanwhile in nalidixic acid and tetracycline the evolution of resistance has increased over time.

CONCLUSIONS

A decrease in the isolation number of Shigella spp. causing TD has been observed. Differential trends in the evolution of the levels of resistance to the tested antibacterial agents have been observed.

Use of population-based surveillance to define the high incidence of shigellosis in an urban slum in Nairobi, Kenya

Background

Worldwide, Shigella causes an estimated 160 million infections and >1 million deaths annually. However, limited incidence data are available from African urban slums. We investigated the epidemiology of shigellosis and drug susceptibility patterns within a densely populated urban settlement in Nairobi, Kenya through population-based surveillance.

Methods

Surveillance participants were interviewed in their homes every 2 weeks by community interviewers. Participants also had free access to a designated study clinic in the surveillance area where stool specimens were collected from patients with diarrhea (≥3 loose stools within 24 hours) or dysentery (≥1 stool with visible blood during previous 24 hours). We adjusted crude incidence rates for participants meeting stool collection criteria at household visits who reported visiting another clinic.

Results

Shigella species were isolated from 224 (23%) of 976 stool specimens. The overall adjusted incidence rate was 408/100,000 person years of observation (PYO) with highest rates among adults 34–49 years old (1,575/100,000 PYO). Isolates were: Shigella flexneri (64%), S. dysenteriae (11%), S. sonnei (9%), and S. boydii (5%). Over 90% of all Shigella isolates were resistant to trimethoprim-sulfamethoxazole and sulfisoxazole. Additional resistance included nalidixic acid (3%), ciprofloxacin (1%) and ceftriaxone (1%).

Conclusion

More than 1 of every 200 persons experience shigellosis each year in this Kenyan urban slum, yielding rates similar to those in some Asian countries. Provision of safe drinking water, improved sanitation, and hygiene in urban slums are needed to reduce disease burden, in addition to development of effective Shigella vaccines.

The bacteriological safety and antimicrobial susceptibility of bacteria isolated from street-vended white lupin (Lupinus albus) in Bahir Dar, Ethiopia

BACKGROUND

Whereas street vended foods are readily available sources of meals for many people across the world, the microbial safety of such food is always uncertain. In developing countries the major sources of food-borne illnesses are street vended foods. The aim of this study was thus to assess the prevalence and antibiogram of bacteria from white lupin in Bahir Dar Town.

METHODS

A total of 40 samples were processed for detection of indicator bacteria and pathogens from December, 2011 to February, 2012 using standard bacteriological techniques. Antimicrobial susceptibility test was performed using the Kirby-Bauer disk diffusion method.

RESULTS

The total coliform counts were 954.2±385 and 756.2±447.3 at the surface and the core of white lupin, respectively. On the other hand, the fecal coliform counts were 880.9±396.6 and 662.1±461.9 at surface and the core, respectively. There was a statistically significant difference in total colifoms and fecal coliform counts between the surface and core of white lupin (p <0.05). Escherichia coli 29 (72.5%), Salmonella spp. 23 (57.5%) and Shigella spp. 8 (20%) were the pathogens isolated. Most bacterial isolates were resistant to tetracycline, cotriamoxazole and erythromycin whereas many of them were sensitive to chloramphenicol, nalidixic acid, gentamicin and ciprofloxacin. The overall multiple antimicrobial resistances rate was 75%.

CONCLUSION

This study revealed contamination of white lupin and a potential health to consumers, and the bacteria isolated showed high rates of multiple drug resistance. Surveillance of antimicrobial resistance should be done on food borne pathogens. In addition, further studies should be conducted on the bacteriological quality of waters used for soaking white lupin.

Decreased susceptibility to antimicrobials among Shigella flexneri isolates in Manipal, South India--a 5 year hospital based study

Shigellosis is endemic in many developing countries and an important cause of bloody diarrhea worldwide. Our study was undertaken as a continuation of our earlier study during 2001 - 2006.The aim of this study was to monitor changes in Shigella serogroups and resistance patterns to antimicrobials among Shigella isolates. Two thousand one hundred fecal samples were obtained from patients with diarrhea during June 2006-June 2011. Isolates were identified by standard microbiological techniques as Shigella spp and the disk diffusion method was used to determine antimicrobial susceptibility following CLSI guidelines. Of the 2,100 fecal samples, 77 (3.7%) contained Shigella spp, of which 73 (94.8%) were S. flexneri, 3 (3.9%) were S. sonnei and 1 (1.3%) was S. dysentriae type 1. S. boydii was not identified. One hundred percent resistance was noted against nalidixic acid. There were high levels of resistance to other antimicrobials: ampicillin (100%), Co-trimoxazole (89.6%), tetracycline (84.4%), ciprofloxacin (87%) and norfloxacin (83.1%). Most of the isolates were susceptible to ceftriaxone except for 2 isolates of S. flexneri. Antibiotic treatment of shigellosis is needed to prevent mortality. Increasing fluoroquinolone resistance leaves us dependent on third generation cephalosporins for treating shigellosis. Emerging resistance to these cephalosporins was seen in our study.

[Drug resistance and molecular epidemiology of Shigella isolated from children with diarrhea]

OBJECTIVE

To investigate the prevalence and antibiotic resistance of Shigella isolated from children with diarrhea for the guidance of clinical treatment and prevention and control of bacillary dysentery.

METHOD

A total of 156 strains of Shigella were isolated from feces of children with diarrhea in Zhejiang Xiaoshan Hospital from January 2008 to December 2010. The antimicrobial resistance of the strains was detected by disk diffusion method and the extended-spectrum beta-lactamases (ESBLs) in these isolates were determined using phenotypic confirmatory test; the isolates of ESBLs producing Shigella sonnei were analyzed by REP-PCR.

RESULT

Among 156 strains of Shigella isolated, the most common groups were Shigella sonnei (130 strains, accounting for 83.3%) and Shigella fleaneri (26 strains, accounting for 16.7%), and 81 (51.9%) strains were identified as ESBLs producers, and the positive rates in 2008, 2009 and 2010 were 32.0%, 41.4% and 59.8%, respectively. The results of antibiotic susceptibility test displayed that the resistance rates of ESBLs producing Shigella to ampicillin, cotrimoxazole, cefotaxime, piperacillin were higher than 90%. However, the resistance rates to cefepime, ceftazidime, levofloxacin and ciprofloxacin were low; The resistance of ESBLs producing strains to piperacillin (100% vs. 77.3%), cefotaxime (100% vs. 0), ceftazidime (14.8% vs. 0), cefepime (28.4% vs. 0), cotrimoxazole (95.1% vs. 86.7%) was significantly higher than that of non-ESBLs producing strains (χ(2) = 20.605, 156.000, 12.037, 24.979, 45.040, respectively; P < 0.05). No isolate was resistant to piperacillin/tazobactam and imipenem. There were 7 genotypes among 74 ESBLs producing Shigella sonnei, respectively type A (50), type B (12), type C (8), type D (1), type E (1), type F (1), and type G (1).

CONCLUSION

The isolation rate of ESBLs-producing isolate was high in Shigella from pediatric patients with diarrhea, and the number is going up year by year, and these ESBLs producing Shigella sonnei strains in genotype A are dominant in recent years, Piperacillin/tazobactam is the drug of choice for children with ESBLs producing Shigella infection.

The co-selection of fluoroquinolone resistance genes in the gut flora of Vietnamese children

Antimicrobial consumption is one of the major contributing factors facilitating the development and maintenance of bacteria exhibiting antimicrobial resistance. Plasmid-mediated quinolone resistance (PMQR) genes, such as the qnr family, can be horizontally transferred and contribute to reduced susceptibility to fluoroquinolones. We performed an observational study, investigating the copy number of PMQR after antimicrobial therapy. We enrolled 300 children resident in Ho Chi Minh City receiving antimicrobial therapy for acute respiratory tract infections (ARIs). Rectal swabs were taken on enrollment and seven days subsequently, counts for Enterobacteriaceae were performed and qnrA, qnrB and qnrS were quantified by using real-time PCR on metagenomic stool DNA. On enrollment, we found no association between age, gender or location of the participants and the prevalence of qnrA, qnrB or qnrS. Yet, all three loci demonstrated a proportional increase in the number of samples testing positive between day 0 and day 7. Furthermore, qnrB demonstrated a significant increase in copy number between paired samples (p<0.001; Wilcoxon rank-sum), associated with non-fluoroquinolone combination antimicrobial therapy. To our knowledge, this is the first study describing an association between the use of non-fluoroquinolone antimicrobials and the increasing relative prevalence and quantity of qnr genes. Our work outlines a potential mechanism for the selection and maintenance of PMQR genes and predicts a strong effect of co-selection of these resistance determinants through the use of unrelated and potentially unnecessary antimicrobial regimes.

Purification and genetic characterisation of the novel bacteriocin LS2 produced by the human oral strain Lactobacillus salivarius BGHO1

The aim of this study was to investigate the antimicrobial potential of Lactobacillus salivarius BGHO1, a human oral strain with probiotic characteristics and a broad inhibitory spectrum both against Gram-positive and Gram-negative pathogens. Here we present the bacteriocin LS2, an extremely pH- and heat-stable peptide with antilisterial activity. LS2 is a novel member of the class IId bacteriocins, unique among all currently characterised bacteriocins. It is somewhat similar to putative bacteriocins from several oral streptococci, including the cariogenic Streptococcus mutans. LS2 is a 41-amino-acid, highly hydrophobic cationic peptide of 4115.1Da that is sensitive to proteolytic enzymes. LS2 was purified from cells of strain BGHO1 by solvent extraction and reverse-phase chromatography. Mass spectrometry was used to determine the molecular mass of the purified peptide. N-terminal amino acid sequencing enabled identification of the LS2 structural gene bacls2 by a reverse genetics approach. Downstream of the bacls2 gene, two bacteriocin-like genes were found, named blp1a and blp1b, and one putative bacteriocin immunity gene named bimlp. We also present the identification of the 242-kb megaplasmid pMPHO1 by pulsed-field gel electrophoresis, which harbours the genes bacls2, blp1a, blp1b and bimlp. Two peptides with antimicrobial activity, whose approximate sizes corresponded to those of blp1a and blp1b, were identified only after culturing strain BGHO1 in a chemically defined medium. This study demonstrated the capacity of Lactobacillus salivarius BGHO1 to produce multiple bacteriocins and further established this strain as a promising probiotic candidate.