Resistant Shigella Research Articles

First report of sexually transmitted multi-drug resistant Shigella sonnei infections in Switzerland, investigated by whole genome sequencing

Shigella sonnei causes foodborne infections, but has recently also been described as a sexually transmitted infection (STI), with increased levels of antimicrobial resistance. We describe three cases of sexually acquired Shigella sonnei infection - the first report of this emerging infection in Switzerland. We used in-house whole genome sequencing (WGS) to investigate possible transmission routes and epidemiological correlations between the three cases. The genomic analysis demonstrated that two of three case isolates were very closely related, with only two single nucleotide polymorphism differences between them, despite being isolated from two unrelated patients at time-points six months apart, and the infections having been acquired at different geographic locations within Europe. All three isolates were found to fall within two of the clusters (1 and 7) defined within UK men who have sex with men (MSM) isolate populations, but with higher divergence, suggesting a more diverse pool circulating within Europe. Phenotypic testing confirmed the genotypic findings, with all three isolates azithromycin resistant, and two out of three resistant to quinolones. This report underlines the importance of the implementation of new sequencing technologies in the investigation of epidemiological aspects of this STI circulating in the population of MSM. In such cases, therapy should always be guided by antimicrobial susceptibility testing owing to increasing resistances. Greater awareness of this emerging sexually transmitted infection is needed.

Characterization of integrons, extended-spectrum β-lactamases, AmpC cephalosporinase, quinolone resistance, and molecular typing of Shigella spp. from Iran

Introduction: The wide distribution of extended-spectrum β-lactamase (ESBL) producing Shigella spp., along with the emergence of fluoroquinolone resistant isolates, is a serious threat to public health, posing a new challenge for the effective treatment of shigellosis. The purpose of this study was to determine the level of antimicrobial resistance, the presence of genes encoding resistance to cephalosporins, and plasmid-mediated quinolone resistance (PMQR) among the clinical isolates of Shigella spp. in Iran.Materials and methods: A total of 142 Shigella isolates were collected from different parts of Iran. All of the cephalosporin resistant Shigella strains were selected based on ESBL and AmpC production. The presence of PMQR regions was assessed in ciprofloxacin-resistant isolates, and genetic relatedness in the isolates was determined.Results: Seventy-eight Shigella isolates were found to be resistant to extended-spectrum cephalosporin (ESC). The blaCTX-M15 was the most prevalent cephalosporinase. Four ESBL-producing isolates were also resistant to ciprofloxacin. Among the PMQR regions, aac(6’)-lb-cr gene was the most prevalent, as it was seen in 83.3% of the ciprofloxacin resistant isolates, while qnrA was positive in 16.7%. Clonal relatedness showed a limited variety of clones was responsible for Shigella infection in the region studied.Conclusion: Overall, our findings indicated that a large number of ESBL producing Shigella spp. were mediated mainly by blaCTX-M15. This study is the first report on ciprofloxacin-resistant ESBL-producing Shigella isolates from patients in Iran.

Azithromycin Resistance in Shigella spp. in Southeast Asia.

ABSTRACTInfection by Shigella spp. is a common cause of dysentery in Southeast Asia. Antimicrobials are thought to be beneficial for treatment; however, antimicrobial resistance in Shigella spp. is becoming widespread. We aimed to assess the frequency and mechanisms associated with decreased susceptibility to azithromycin in Southeast Asian Shigella isolates and use these data to assess appropriate susceptibility breakpoints. Shigella isolates recovered in Vietnam and Laos were screened for susceptibility to azithromycin (15 μg) by disc diffusion and MIC. Phenotypic resistance was confirmed by PCR amplification of macrolide resistance loci. We compared the genetic relationships and plasmid contents of azithromycin-resistant Shigella sonnei isolates using whole-genome sequences. From 475 available Shigella spp. isolated in Vietnam and Laos between 1994 and 2012, 6/181 S. flexneri isolates (3.3%, MIC ≥ 16 g/liter) and 16/294 S. sonnei isolates (5.4%, MIC ≥ 32 g/liter) were phenotypically resistant to azithromycin. PCR amplification confirmed a resistance mechanism in 22/475 (4.6%) isolates (mphA in 19 isolates and ermB in 3 isolates). The susceptibility data demonstrated the acceptability of the S. flexneri (MIC ≥ 16 g/liter, zone diameter ≤ 15 mm) and S. sonnei (MIC ≥ 32 g/liter, zone diameter ≤ 11 mm) breakpoints with a <3% discrepancy. Phylogenetic analysis demonstrated that decreased susceptibility has arisen sporadically in Vietnamese S. sonnei isolates on at least seven occasions between 2000 and 2009 but failed to become established. While the proposed susceptibility breakpoints may allow better recognition of resistant isolates, additional studies are required to assess the impact on the clinical outcome. The potential emergence of azithromycin resistance highlights the need for alternative options for management of Shigella infections in countries where Shigella is endemic.

Plasmid-Mediated Quinolone Resistance in Shigella flexneri Isolated From Macaques.

Non-human primates (NHPs) for biomedical research are commonly infected with Shigella spp. that can cause acute dysentery or chronic episodic diarrhea. These animals are often prophylactically and clinically treated with quinolone antibiotics to eradicate these possible infections. However, chromosomally- and plasmid-mediated antibiotic resistance has become an emerging concern for species in the family Enterobacteriaceae. In this study, five individual isolates of multi-drug resistant Shigella flexneri were isolated from the feces of three macaques. Antibiotic susceptibility testing confirmed resistance or decreased susceptibility to ampicillin, amoxicillin-clavulanic acid, cephalosporins, gentamicin, tetracycline, ciprofloxacin, enrofloxacin, levofloxacin, and nalidixic acid. S. flexneri isolates were susceptible to trimethoprim-sulfamethoxazole, and this drug was used to eradicate infection in two of the macaques. Plasmid DNA from all isolates was positive for the plasmid-encoded quinolone resistance gene qnrS, but not qnrA and qnrB. Conjugation and transformation of plasmid DNA from several S. flexneri isolates into antibiotic-susceptible Escherichia coli strains conferred the recipients with resistance or decreased susceptibility to quinolones and beta-lactams. Genome sequencing of two representative S. flexneri isolates identified the qnrS gene on a plasmid-like contig. These contigs showed >99% homology to plasmid sequences previously characterized from quinolone-resistant Shigella flexneri 2a and Salmonella enterica strains. Other antibiotic resistance genes and virulence factor genes were also identified in chromosome and plasmid sequences in these genomes. The findings from this study indicate macaques harbor pathogenic S. flexneri strains with chromosomally- and plasmid-encoded antibiotic resistance genes. To our knowledge, this is the first report of plasmid-mediated quinolone resistance in S. flexneri isolated from NHPs and warrants isolation and antibiotic testing of enteric pathogens before treating macaques with quinolones prophylactically or therapeutically.

Molecular analysis of integrons and antimicrobial resistance profile in Shigella spp. isolated from acute pediatric diarrhea patients.

Introduction: Shigella spp. is a growing global health concern due to increasing multiple drug resistance, commonly resulting in therapeutic failure. Integrons are gene expression systems run by integrase genes. The aims of this study were detection of class I, II and III integrons and assessment of antimicrobial resistance in Shigella spp. isolated from acute pediatric diarrhea patients.Materials and methods: From January to December 2015, 16 Shigella spp. were isolated from 310 non-duplicative diarrheal stool samples in Children’s Medical Center, Tehran, Iran. The isolates were analyzed for their antibiotic susceptibility using CLSI guidelines M100-S14. Multiplex PCR was used for amplification of I, II and III integron-associated integrase (intl) genes.Results: Of 310 stool samples, 16 (5.2%) were positive for Shigella spp., in 7 of them S. sonnei and in 9 of them S. flexneri were identified. Results of the antimicrobial susceptibility test showed that 6.2%, 50%, 31.2%, 6.2%, 81.2%, 56.2% and 31.2% of the isolates were resistant to gentamicin, chloramphenicol, nalidixic acid, ciprofloxacin, tetracycline, ampicillin and trimethoprim-sulfamethoxazole, respectively. Multiplex PCR results revealed that 6.2% (1/16), 31.2% (5/16), 50% (8/16) of Shigella isolates carried intlI, intlII and both intlI/intllI genes. No class 3 integrons were detected.Discussion: In this study, multidrug resistance was seen in Shigella isolates similar to that in isolates from other geographical areas. This is possible due to inappropriate use of antimicrobials. Furthermore, prevalence of multidrug resistance was significantly linked to the presence of integrin genes. Conclusion: A class 2 integron plays a role in presence of multidrug resistance in Shigella spp. It is vital to prevent the spread of antibiotic resistance through continuous monitoring.

Molecular analysis of multidrug resistance in clinical isolates of Shigella spp. from 2001-2010 in Kolkata, India: role of integrons, plasmids, and topoisomerase mutations.

To understand the genetic basis of high drug resistance in Shigella, 95 clinical isolates of Shigella spp. (2001–2010) were obtained from the Infectious Diseases Hospital, Kolkata, India. Ninety-three isolates were resistant to three or more antibiotics. Resistance to nalidixic acid, trimethoprim, streptomycin, and co-trimoxazole was most common in this population. Dendrogram analysis showed that S. sonnei strains were more clonally related when compared to the other Shigella species. The role of mobile genetic elements and chromosome-borne resistance factors was analyzed in detail. Integron analysis indicated the preponderance of class 2 and atypical class 1 integrons in that population. Typical class 1 integron was present in only one S. sonnei isolate and harbored trimethoprim resistance-encoding gene dfrV, while atypical class 1 integrons harbored dfrA1–aadA or blaOXA-aadA gene cassettes responsible for resistance to trimethoprim, aminoglycosides, and β-lactams. Class 2 integrons harbored either dfrA1-sat-aadA or dfrA1-sat gene cassettes. Most importantly, a novel gene cassette array InsE-InsO-dfrA1-sat was found in class 2 integron of S. sonnei NK4846. Many of the resistance traits for antibiotics such as trimethoprim, co-trimoxazole, kanamycin, ampicillin, and tetracycline were transferred from parent Shigella isolates to recipient Escherichia coli during conjugation, establishing the role of plasmids in horizontal transfer of resistance genes. Multiple mutations such as S80→I, S83→L, and D87→G/N/Y in quinolone resistance determining regions of topoisomerases from the representative quinolone-resistant isolates could explain the spectrum of minimal inhibitory concentration values for various quinolones. To the best of our knowledge, this is the first comprehensive report that describes the contribution of mobile (plasmids, integrons, and quinolone resistance genes named qnr) and innate genetic elements (mutations in topoisomerases) in determining the resistance phenotype of all the four species of Shigella over a span of ten years.

Genotypic Diversity of Multidrug Resistant Shigella species from Iran.

BackgroundIn many developing countries, shigellosis is endemic and also occurs in epidemics and treatment of multidrug-resistant (MDR) isolates are important. The aims of this study were to determine the antimicrobial susceptibility, prevalence of class 1 and 2 integrons and the clonal relatedness of isolates.Materials and MethodsAntimicrobial susceptibility tests were performed by disc diffusion method. Polymerase chain reaction (PCR)-sequencing technique was employed for detection and characterization of integrons. The genetic relatedness was evaluated by using enterobacterial repetitive intergenic consensus (ERIC) PCR.ResultsThere was a high percentage of resistance to trimethoprim-sulfamethoxazole (TMP/SMX) (93.7%), ampicillin (AMP) (87.3%), streptomycin (STR) (84.5%) and tetracycline (TET) (78.9%). Multidrug resistant phenotype was seen in 95.1% of total isolates. Most common MDR profile was TMP/SMX/STR/AMP resistant pattern. Among the 142 Shigella spp. analyzed in this study, 28 isolates were positive for class 1 integron with two types of gene cassette arrays (dfrA17/aadA5 = 31.7% and dfrA7 = 3.8%). The class 2 integron was more frequently detected among the isolates (94.7%) with dfrA1/sat1/aadA1 (69.4%) and dfrA1/sat1 (30.6%) gene cassettes. ERIC-PCR results showed 6, 5, 4 and 3 main genotypes among S. flexneri, S. sonnei, S. boydii and S. dysenteriae isolates, respectively.ConclusionsOur findings revealed that multidrug resistant Shigella species with high prevalence of class 2 integron were very common in Iran. In addition, ERIC-PCR patterns showed limited variety of clones are responsible for shigellosis in the region of the study.

Emergence of antibiotic resistant Shigella species: A matter of concern.

A major threat to the world is the emergence of antibiotic resistant bacteria, which has rendered previously susceptible drugs useless and increased the rate of therapeutic failures. Shigella species, which are the causative organism of Shigellosis, were earlier susceptible to ampicillin, chloramphenicol, co-trimoxazole and nalidixic acid but now they have developed resistance against fluoroquinolones, cephalosporins and azithromycin. Many shigellosis outbreaks have been reported by resistant strains of Shigella species. This review attempts to provide a brief overview about the scenario of shigellosis and the emergence as well as ubiquitous nature of multidrug resistant (MDR) Shigella species.

Epidemic characterization and molecular genotyping of Shigella flexneri isolated from calves with diarrhea in Northwest China

BackgroundThe widespread presence of antibiotics resistance genes in pathogenic bacteria can cause enormous problems. Food animals are one of the main reservoirs of intestinal pathogens that pose a potential risk to human. Analyzing the epidemiological characteristics and resistance patterns of Shigella flexneri in calves is necessary for animal and human health.Methods and resultsA total of 54 Shigella flexneri isolates, including six serotypes (1a, 2a, 2b, 4a, 6 and Xv), were collected from 837 fecal samples obtained from 2014 to 2016. We performed pulsed-field gel electrophoresis (PFGE) and applied the restriction enzyme NotI to analyze the genetic relatedness among the 54 isolates and to categorize them into 31 reproducible and unique PFGE patterns. According to the results of antimicrobial susceptibility tests, all 26 Shigella flexneri 2a serotypes were resistant to cephalosporin and/or fluoroquinolones. The genes blaTEM-1, blaOXA-1, and blaCTX-M-14 were detected in 19 cephalosporin-resistant S. flexneri 2a isolates. Among 14 fluoroquinolone-resistant isolates, the aac(6′)-Ib-cr gene was largely present in each strain, followed by qnrS (5). Only one ciprofloxacin-resistant isolate harbored the qepA gene. Sequencing the quinolone resistance determining regions (QRDRs) of the fluoroquinolone-resistant isolates revealed two point mutations in gyrA (S83 L, D87N/Y) and a single point mutation in parC (S80I). Interestingly, two gyrA (D87N/Y) strains were resistant to ciprofloxacin.ConclusionsThe current study enhances our knowledge of Shigella in cattle, although continual surveillance is necessary for the control of shigellosis. The high level of cephalosporin and/or fluoroquinolone resistance in Shigella warns us of a potential risk to human and animal health.

Relationship between drug resistance and the clustered, regularly interspaced, short, palindromic repeat-associated protein genes cas1 and cas2 in Shigella from giant panda dung.

Background:To detect drug resistance in Shigella obtained from the dung of the giant panda, explore the factors leading to drug resistance in Shigella, understand the characteristics of clustered, regularly interspaced, short, palindromic repeats (CRISPR), and assess the relationship between CRISPR and drug resistance.Methods:We collected fresh feces from 27 healthy giant pandas in the Giant Panda Conservation base (Wolong, China). We identified the strains of Shigella in the samples by using nucleotide sequence analysis. Further, the Kirby-Bauer paper method was used to determine drug sensitivity of the Shigella strains. CRISPR-associated protein genes cas1 and cas2 in Shigella were detected by polymerase chain reaction (PCR), and the PCR products were sequenced and compared.Results:We isolated and identified 17 strains of Shigella from 27 samples, including 14 strains of Shigella flexneri, 2 strains of Shigella sonnei, and 1 strain of Shigella dysenteriae. Further, drug resistance to cefazolin, imipenem, and amoxicillin–clavulanic acid was identified as a serious problem, as multidrug-resistant strains were detected. Further, cas1 and cas2 showed different degrees of point mutations.Conclusion:The CRISPR system widely exists in Shigella and shares homology with that in Escherichia coli. The cas1 and cas 2 mutations contribute to the different levels of resistance. Point mutations at sites 3176455, 3176590, and 3176465 in cas1 (a); sites 3176989, 3176992, and 3176995 in cas1 (b); sites 3176156 and 3176236 in cas2 may affect the resistance of bacteria, cause emergence of multidrug resistance, and increase the types of drug resistance.

Investigation of Efflux-Mediated Tetracycline Resistance in Shigella Isolates Using the Inhibitor and Real Time Polymerase Chain Reaction Method

Shigella spp. are gram negative bacteria, which are of global public health importance. The growing of multidrug-resistant Shigella isolates are a major problem around the world. Overall, 50 isolates of Shigella spp. from children diarrheic stools were studied. The isolates were identified and confirmed using biochemical, serological and molecular methods (ipaH, wbgZ and rfc genes). Antimicrobial susceptibility test was done according to the Clinical and Laboratory Standards Institute (CLSI) guidelines against minocycline, tetracycline, doxycycline, ampicillin, streptomycin, trimethoprim-sulfamethoxazole, nalidixic acid, norfloxacin, ciprofloxacin and levofloxacin. Also, the role of efflux pump in defense of Shigella against tetracycline was investigated by Minimum Inhibitory Concentration (MIC) with and without an efflux pump inhibitor. Detection of tetA, tetB, tetC and tetD genes in Shigella was evaluated by conventional Polymerase Chain Reaction (PCR) and real time PCR. Molecular identification revealed a prevalence of 14% for Shigella flexneri and 86% for Shigella sonnei. Minimum Inhibitory Concentration (MIC) of 90% of resistant isolates was changed in the presence CCCP. Results of conventional PCR exhibited that 66% of isolates were positive for tetA, while according to real time PCR method, 90% of isolates carried tetA. Positive results for tetB were 12% and 18% by conventional and real time PCR methods, respectively. No positive results were detected for tetC and tetD. Also, tetB was detected only in S. flexneri while tetA was detected in both S. flexneri and S. sonnei. It seems that efflux-mediated tetracycline resistance to tetracycline in S. flexneri can be related to tetB, however resistance in S. sonnei can be related to the expression of tetA.

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

BackgroundBacillary 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.MethodsSurveillance 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.ResultsThe 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.ConclusionsThe 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.

A study on the antibiotic resistance of Shigella

Background The hospital morbidity caused by Shigella or dysen-tery ranges between 0.3 to 2.9%. Irrational use of antibiotics causesa persistent diarrhea and may lead to drug resistance.Objectives With various kinds of antibiotics available in Indone-sia at the moment, this study aimed to anticipate the kinds of anti-biotics appropriate for shigellosis and to evaluate the clinical spec-trum of dysentery in children in Indonesia.Method The study involved 50 children diagnosed with dysenteryor dysentery-like syndrome, aged 1 to 12 years, who came to fourdifferent hospitals in Jakarta, from November 2001 to April 2002.Parents were asked for their consent. Interviewers recorded de-tails of the children’s history of illness and the physical examina-tions. Stool culture and resistance tests were done.Results Fifty dysentery cases, comprising 30 males and 20 fe-males, 98% aged from 1 to 5 years, came to the four hospitalsduring the study period. Only 24 cases had positive Shigella cul-tures, of which 87% were Shigella flexneri and 17% were Shigellasonnei. The clinical manifestations of shigellosis were bloody stools(83%), mucus in the stool (75%), and watery diarrhea (96%). Fe-ver and tenesmus were absent in 67% and 92% of subjects, re-spectively. Almost 87% of shigellosis cases were resistant tocotrimoxazole; all were sensitive to colistin and most were sensi-tive to nalidixic acid.Conclusion This data suggests that colistin and nalidixic acid aredrugs of choice for dysentery syndrome. The clinical manifesta-tion of dysentery is not always accompanied by bloody stools butmostly incorporates watery diarrhea and mucus in the stool

The Emergence of Quinolone Resistant Shigella sonnei, Pondicherry, India.

Ciprofloxacin resistant Shigella sonnei across the globe have been increasing alarmingly. In order to understand the emergence of S.sonnei with respect to ciprofloxacin resistance in our patient population, the following study was carried out. Of the 184 Shigella sp. Isolated from 2012 to 2015, 34 S.sonnei which were confirmed by standard methods and subjected to antimicrobial susceptibility testing were selected. The minimum inhibitory concentrations (MICs) of 16/34 quinolone resistant isolates tested ranged from 4micrograms/ml to 16micrograms/ml for ciprofloxacin, from 16 micrograms/ml to 64 micrograms/ml for ofloxacin and from 16micrograms/ml to 64micrograms/ml for levofloxacin. Sequence determination of the quinolone resistance determining regions of gyrA, gyrB, parC, and parE genes showed mutations in GyrA at Gln69/Trp, Phe71/Ser, Ser72/Pro, Met75/Leu, Ser90/Cys, Met94/Leu, His106/Pro, Asn161/His, Thr163/Ala and in ParC at Ala64/Asp. Among the plasmid-mediated quinolone resistance (PMQRs) targets investigated,qnrB was the most (93.7%) prevalent followed by qnrC (18.7%). None hadqnrA, qnrS and qepA. Two (0.1%) of the isolates harboured theaac(6’)-lb gene. Drug accumulation assay detected the presence of efflux pump activity in 9/15 (60%) among ciprofloxacin resistant isolates. All isolates harboured the ipaH gene followed by ial (17.6%), sen (11.7%), set1A&set1B (5.8%) genes. None had stx1 element. PCR for Enterobacterial repetitive intergenic consensus (ERIC) sequences resulted in 4 unique clusters, of which Type III was the most (44%) dominant but there was no correlation between the ERIC types and the antibiotic resistance pattern or the virulence profile. A documented increase in S.sonnei harbouring the qnrgenes and some unusual genes like set1Aand indicate an ongoing process of horizontal gene transfer. The accumulation of novel mutations in GyrA and ParC in the presence of efflux pump and PMQR genes contributed to the raised MIC to quinolones. These findings are crucial in our understanding of quinolone resistance in these isolates.

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.

Fluoroqunilone resistance in Shigella over a decade In India: Do we have Plasmid-mediated quinolone resistance?

Fluoroqunilone resistance in Shigella over a decade In India: Do we have Plasmid-mediated quinolone resistance?

Patterns of Acute Non Amebiasis Dysentery in Adults

iarrhea is still a major cause of death in many People all over the world. Acute diarrhea causes 3 million people death annually. Etiologic agents for bacterial dysentery are: Shigella (dysenteria, flexneri, boydii, sonnei), Salmonella (Typhi and para typhi), Campylobacter (jejuni) and Yersinia (entero colitica). The most common agent in developing countries is shigella Dysenteria and in developed countries is campylobacter jejuni [1]. While dysentery is a self limited disease, the antibiotic treatment not only reduces the symptomatic time, but also the excretion of the microbes, preventing its infection exposing other people [2]. The present study was aimed to determine patterns of acute non amebiasis dysentery in adult. This cross-sectional study performs in 2012. Patients with acute invasive diarrhea (bloody or mucoid diarrhea) for shorter than 3 days duration or watery diarrhea with fever or chill or tenesmus enrolled. Exclusion criteria were lactating and pregnant women, antibiotic therapy in 72 h past, patients with high toxicity and poor general condition and complications. In first, we get from all patients a sample of stool for direct examination and culture and antibiogram. Dysentery confirmed by positivity stool for WBC and RBC without amebiasis, then some of patients received azithromycin and other group received tab ciprofloxacin 500 mg/12 h for 5 days. After 48 h patients were examined for fever, general condition, decreased diarrhea and tenesmus. For patients with good clinical response, duration of treatment completed for 5 days but in groups without good clinical response, with use of results of culture and antibiogram, treatment changed. Stool culture was done from all patients in 5th day after treatment. Also patients evaluate for drug reactions in two groups. Data was analyzed using SPSS-11 software and χ test was used p<0.05 was set as the significant level. From 84 patients, 52 (61.9%) patients were male and 32 patients (38.9%) were female. In 29 (34.5%) patients culture result was negative. Shigella dysenteria cultured from 41 (48.8%) patients and other organisms (E. coli, Salmonella paratyphi A, Campylobacter jejuni cultured in 14 (16.6%) patients. Bloody diarrhea was seen at 38.1% patients and 27.3% had watery diarrhea and 32% mucoid and mixed diarrhea. From 55 patients that had antibiogram, 32 (58.1%) were sensitive to ciprofloxacin and 41 (74.4%) to azithromycin. Clinical response in azithromycin was more than ciprofloxacin 93.5% versus 88.6%. Stool cultures were negative in 100% patients at the end of treatment. In our study in patients with dysenteria, Shigella dysenteria is the most common etiologic agent but is not only bacterial etiology and other Gram negative bacillus example Salmonella paratyphi A, Campylobacter jejuni and E. coli. This may be to Shigella dysenteria low tolerance to hard environment conditions that it difficult Shigella dysenteria diagnosis or early antibiotic use by patients with dysenteria. Other studies showed quinolone resistance in Shigella (all species) has increased at an alarming speed, reinforcing the importance of continuous monitoring of antimicrobial resistance in Shigella (all species) [3]. In our study microbiological resistance for azithromycin was 19.3% and for ciprofloxacin was 23.8%, that indicated Shigella dysenteria resistant to new antibiotics example macrolides and quinolones is increased but clinical response to azithromycin and ciprofloxacin were good.

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

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. 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. 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. 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.

Prevalence and antimicrobial susceptibility patterns of Shigella among acute diarrheal outpatients in Mekelle hospital, Northern Ethiopia.

BackgroundEmergence of increased antimicrobial resistance of Shigella species is a global challenge, particularly in developing countries where increased misuse of antimicrobial agents occurs. There is no published data in the study area on the prevalence and antimicrobial susceptibility patterns of Shigella among acute diarrheal patients. This study was therefore, under taken to fill this gap.MethodsUsing cross sectional study method, stool specimens were collected from 216 patients with acute diarrhea at Mekelle Hospital from August to November 2014. Standard bacteriological methods were used to isolate and determine the antimicrobial susceptibility patterns of the isolates, and data were analyzed using SPSS version 20.ResultsOut of the total 216 participants, Shigella was isolated from 15 (6.9 %) of the participants. Ten (66.7 %) of the positive isolates were from children <15 years (p = 0.005). Latrine availability, source of drinking water and hand washing habits before meal were statistically significant with shigellosis (p < 0.05). Isolates of Shigella showed 100, 86.7 and 66.7 % resistance to amoxicillin, amoxicillin and cotrimoxazole respectively. Low levels of resistance were observed for norfloxacin and ciprofloxacin (6.7 % each). Overall, 80 % of the isolates showed multidrug resistance.ConclusionShigella isolates were highly resistant to amoxicillin, amoxicillin and cotrimoxazole. However, ciprofloxacin and norfloxacin were effective. Antibiotic surveillance is needed to prevent further emergence of drug resistant Shigella strains. More has to be done in the availability of latrine, supply of safe drinking water to the community to reduce the disease burden.

YEŞİL ÇAYIN AĞIZ VE DİŞ SAĞLIĞI ÜZERİNE ETKİSİ

Tea is one of the most consumed beverages. Past two decades, because of benefits on human health, there is a rising interest on green tea. Green tea has antifungal, antimicrobial and antioxidant activition and also it reduces, recuding incidence of cardiovascular disease, obesity and oral cancer. Polyphenol content of green tea has inhibitory effect againts growth of various patogens such as Helicobakter pylori, metisilin resistant mutans, Streptococcus sobrinus, Salmonella typhi, Shigella dysentery, Shigella flexneri and Vibrio cholera.Green tea has also anticariogenic efficiency with inhibiting microorganisms such as S. mutans and S. sobrinus. Green tea is also effective agent against periodontal disease and dental erosion. The purpose of this review is to investigate the effects of green tea on oral health