Helicobacter pylori infection in pregnant women:Gastrointestinal symptoms and pregnancy-related disorders

Helicobacter pylori(H.Pylori)is a gram-negative,flagellated and spiral-shaped bacterial pathogen that impacts approximately 46%among pregnant women globally and has been associated with various maternal-fetal complications.Iron deficiency anemia,fetal growth restriction,cardiovascular diseases,and insufficient nutrient absorption can be observed in pregnant women,as well as miscarriages and pregnancy-specific hypertensive disease,such as pre-eclampsia.Thus,the evidence supports the influence of H.pylori infection on fetal implantation/placentation failure,and positive strains of the cytotoxin-associated gene A of H.Pylori were reported as the most prevalent in these conditions.However,current knowledge indicates a relationship between this infection and the occurrence of hyperemesis gravidarum,characterized by frequent nausea and vomiting.Regarding the diagnosis of this bacterial infection,non-invasive approaches such as stool antigen test,urea breath test,and serological tests are more accepted during pregnancy,as they are easy to carry out and cost-effective.Finally,the bacteria eradication therapy should consider the risks and benefits for the pregnant woman and her child,with pharmacological intervention depending on the clinical presentation.

Three-dimensional models of antigens with serodiagnostic potential for leprosy:An in silico study

BACKGROUND Leprosy is a disease caused by Mycobacterium leprae(M.leprae),an intracellular pathogen that has tropism and affects skin and nervous system cells.The disease has two forms of presentation:Paucibacillary and multibacillary,with different clinical and immunological manifestations.Unlike what occurs in the multibacillary form,the diagnostic tests for the paucibacillary form are nonspecific and not very sensitive,allowing the existence of infected individuals without treatment,which contributes to the spread of the pathogen in the population.To mitigate this contamination,more sensitive diagnostic tests capable of detecting paucibacillary patients are needed.AIM To predict the three-dimensional structure models of M.leprae antigens with serodiagnostic potential for leprosy.METHODS In this in silico study,satisfactory templates were selected in the Protein Data Bank(PDB)using Basic Local Alignment Search Tool to predict the structural templates of ML2038,ML0286,ML0050,and 85B antigens by comparative modeling.The templates were selected according to general criteria such as sequence identity,coverage,X-ray resolution,Global Model Quality Estimate value and phylogenetic relationship;Clustal X 2.1 software was used in this analysis.Molecular modeling was completed using the software Modeller 9v13.Visualization of the models was made using ViewerLite 4.2 and PyMol software,and analysis of the quality of the predicted models was performed using the QMEAN score and Z-score.Finally,the three-dimensional moels were validated using the MolProbity and Verify 3D platforms.RESULTS The three-dimensional structure models of ML2038,ML0286,ML0050,and 85B antigens of M.leprae were predicted using the templates PDB:3UOI(90.51%identity),PDB:3EKL(87.46%identity),PDB:3FAV(40.00%identity),and PDB:1F0N(85.21%identity),respectively.The QMEAN and Z-score values indicated the good quality of the structure models.These data refer to the monomeric units of antigens,since some of these antigens have quaternary structure.The validation of the models was performed with the final three-dimensional structure-monomer(ML0050 and 85B antigens)and quaternary structures(ML2038 and ML0286).The majority of amino acid residues were observed in favorable and allowed regions in the Ramachandran plot,indicating correct positioning of the side chain and absence of steric impediment.The MolProbity score value and Verify 3D results of all models indicated a satisfactory prediction.CONCLUSION The polarized immune response against M.leprae creates a problem in leprosy detection.The selection of immunodominant epitopes is essential for the development of more sensitive serodiagnostic tests,for this it is important to know the three-dimensional structure of the antigens,which can be predicted with bioinformatics tools.

Analysis of clinical characteristics and risk factors between elderly patients with severe and nonsevere Omicron variant infection

BACKGROUND Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has led to millions of confirmed cases and deaths worldwide.Elderly patients are at high risk of developing and dying from COVID-19 due to advanced age,decreased immune function,intense inflammatory response,and comorbidities.Shanghai has experienced a wave of infection with Omicron,a new variant of SARS-CoV-2,since March 2022.There is a pressing need to identify clinical features and risk factors for disease progression among elderly patients with Omicron infection to provide solid evidence for clinical policy-makers,public health officials,researchers,and the general public.AIM To investigate clinical characteristic differences and risk factors between elderly patients with severe and nonsevere Omicron SARS-CoV-2 variant infection.METHODS A total of 328 elderly patients with COVID-19 admitted to the Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from April 2022 to June 2022 were enrolled and divided into a severe group(82 patients)and a nonsevere group(246 patients)according to the diagnosis and treatment protocol of COVID-19(version 7).The clinical data and laboratory results of both groups were collected and compared.A chi-square test,t test,Mann-Whitney U test,hierarchical log-rank test,univariate and multivariate logistic regression,and hierarchical analyses were used to determine significant differences.RESULTS The severe group was older(84 vs 74 years,P<0.001),included more males(57.3%vs 43.9%,P=0.037),had a lower vaccination rate(P<0.001),and had a higher proportion of comorbidities,including chronic respiratory disease(P=0.001),cerebral infarction(P<0.001),chronic kidney disease(P=0.002),and neurodegenerative disease(P<0.001),than the nonsevere group.In addition,severe disease patients had a higher inflammatory index(P<0.001),greater need for symptomatic treatment(P<0.001),longer hospital stay(P=0.011),extended viral shedding time(P=0.014),and higher mortality than nonsevere disease patients(P<0.001).No difference was observed in the application of Paxlovid in the severe and nonsevere groups(P=0.817).Oxygen saturation,cerebral infarction,and D-dimer were predictive factors for developing severe disease in patients with COVID-19,with D-dimer having an excellent role(area under the curve:90.1%,95%CI:86.1-94.0%).In addition,D-dimer was a risk factor for developing severe COVID-19 according to multivariate stratified analysis.CONCLUSION The clinical course of severe COVID-19 is complex,with a higher need for symptomatic treatment.D-dimer is a suitable biomarker for identifying patients at risk for developing severe COVID-19.

Monkeypox in humans:Transmission,pathophysiology,diagnosis,treatment,prevention,and all recent updates

The Centers for Disease Control and Prevention(CDC)is monitoring an epidemic of monkeypox infection in the United States.The outbreak is now global and more than 6900 cases have already been reported.There are 83 confirmed cases among children and adolescents,as shown in the report published on November 3,2022,in the USA.However,monkeypox in pediatric patients is still infrequent(<0.3%of total cases).Among cases in the United States,16 cases were in children<5 years,12 in the age group 5-12 years,and 55 cases in adolescents 13-17 years old.In the adolescent age group,89%were male.For children<12 years of age,close physical contact with an adult household with monkeypox was the primary exposure,but for adolescents,male-to-male sexual contact was found more frequently.The CDC advised United States healthcare providers to remain vigilant for patients with a rash resembling monkeypox,even if there is no history of travel to a country with high risk.This article summarizes the history and epidemiology of monkeypox with a specific emphasis on clinical features and management in pediatric patients.

Brucellosis,a diagnostic dilemma,presenting atypically in a child with terminal ileitis:A case report

BACKGROUND Brucellosis is endemic in India with seropositivity rates as high as 10%in children in the eastern states,yet the disease is not on the radar when a differential diagnosis of pyrexia of unknown origin(PUO)is being considered,especially in children in urban set-up.This may be because of the non-specific multitude of systemic symptoms seen in this disease and the lack of awareness among clinicians.CASE SUMMARY We present a case of a 13-year-old boy,who came with a history of undulating fever for the past three and a half months,loss of appetite,and abdominal pain.The child had visited several pediatricians and was even admitted to a tertiary care hospital for PUO evaluation,but to no avail.He presented to us after three and half months of suffering and weight loss of more than 10%of body weight.His ultrasonography revealed thickening of the terminal ileum.His blood culture grew Brucella melitensis.A diagnosis of Brucellosis with terminal ileitis was made.Brucella serology by enzyme-linked immunoassay(ELISA)was positive for both IgG and IgM.He was treated with doxycycline and Rifampicin along with syrup multivitamin and zinc,for 6 wk.There was remarkable improvement with gain in 4 kg body weight within 2 mo of completing treatment.History revealed consumption of unpasteurized milk and contact with cattle.CONCLUSION Clinical suspicion,detailed history,appropriate laboratory investigations are the three pillars for diagnosing Brucellosis in patients presenting with vague symptoms.

Emerging leishmaniasis in southern Himalayas:A mini-review

Leishmaniasis is a vector-borne parasitic disease affecting millions of people worldwide.However,in the last decade,the number of cases has been reduced from well-documented endemic parts,but sporadic cases have been reported widely from various non-endemic areas,especially from the southern Himalayan zone.This raises concerns about the emergence of new ecological niches.This warrants a critical evaluation of key factors causing this rapid spread and possibly indigenous transmission.This mini-review article is aimed to briefly address the parasite,the vector,and the environmental aspects in the transmission of leishmaniasis in these new foci against a background of worldwide endemic leishmaniasis with a special focus on the southern Himalayan zone.As the lack of knowledge about the causative parasites,vectors,reservoir hosts,atypical presentations,and their management make the problem serious and may lead to the emergence of public health issues.The present works also reviewed the existing information regarding clinical variations,diagnostic methods,treatment,its outcome,and ignite for further research in these aspects of the disease.

Medical errors, infection-control breaches and the use of adulterated and misbranded medical devices

Several well-publicized cases of improper cleaning,disinfection or sterilization of contaminated reusable medical equipment that posed an increased risk of patientto-patient disease transmission were reported within the past few years,resulting in the notification of approximately 20 000 patients.These medical errors,the specific infection-control standards they breached,and assessments of the risk of infection associated with each are discussed.Other topics discussed include the Food and Drug Administration’s(FDA)regulation of medical devices and infection-control products;the use of adulterated,misbranded,and investigational devices;consent decrees and associated Certificates of Medical Necessity;and informed patient consent.Focus is placed on liquid chemical sterilization,its history,and the FDA’s recent censure and discontinuation of a medical device labeled with this claim,namely,the STERIS System 1 processor.Recommendations are provided for healthcare facilities,regulatory agencies,manufacturers of reusable medical devices,and professional healthcare organizations and administrations to improve public health and prevent healthcareassociated infections.

Acinetobacter baumannii:An emerging pathogenic threat to public health

Over the last three decades, Acinetobacter has gained importance as a leading nosocomial pathogen, partly due to its impressive genetic capabilities to acquire resistance and partly due to high selective pressure, especially in critical care units. This low-virulence organism has turned into a multidrug resistant pathogen and now alarming healthcare providers worldwide. Acinetobacter baumanni(A. baumannii) is a major species, contributing about 80% of all Acinetobacter hospital-acquired infections. It disseminates antibiotic resistance by virtue of its extraordinary ability to accept or donate resistance plasmids. The procedures for breaking the route of transmission are still proper hand washing and personal hygiene(both the patient and the healthcare professional), reducing patient's biofilm burden from skin, and judicious use of antimicrobial agents. The increasing incidence of extended-spectrum beta-lactamases and carbapenemases in A. baumannii leaves almost no cure for these "bad bugs".To control hospital outbreaks of multidrug resistantAcinetobacter infection, we need to contain their dissemination or require new drugs or a rational combination therapy. The optimal treatment for multidrug-resistant A. baumannii infection has not been clearly established, and empirical therapy continues to require knowledge of susceptibility patterns of isolates from one's own institution. This review mainly focused on general features and introduction to A. baumannii and its epidemiological status, potential sources of infection, risk factors, and strategies to control infection to minimize spread.

Physiological functions and clinical implications of fibrinogen-like 2:A review

Fibrinogen-like 2(FGL2) encompasses a transmembrane(m FGL2) and a soluble(s FGL2) form with differential tertiary structure and biological activities. Typically, m FGL2 functions as prothrombinase that is capable of initiating coagulation in tissue without activation of the blood clotting cascade, whereas s FGL2 largely acts as an immunosuppressor that can repress proliferation of alloreactive T lymphocytes and maturation of bone marrow dendritic cells. Protein sequences of FGL2 exhibit evolutionary conservation across wide variety of species, especially at the carboxyl terminus that contains fibrinogen related domain(FRED). The FRED of FGL2 confers specificity and complexity in the action of FGL2, including receptor recognition, calcium affiliation, and substrate binding. Constitutive expression of FGL2 during embryogenesis and in mature tissues suggests FGL2 might be physiologically important. However, excessive induction of FGL2 under certain medical conditions(e.g. pathogen invasion) could trigger complement activation, inflammatory response,cellular apoptosis, and immune dysfunctions. On the other hand, complete absence of FGL2 is also detrimental as lack of FGL2 can cause autoimmune glomerulonephritis and acute cellular rejection of xenografts. All these roles involve m FGL2, s FGL2, or their combination. Although it is not clear how m FGL2 is cleaved off its host cells and secreted into the blood, circulating s FGL2 has been found correlated with disease severity and viral loading among patients with human hepatitis B virus or hepatitis C virus infection. Further studies are warranted to understand how FGL2 expression is regulated under physiological and pathological conditions. Even more interesting is to determine whether m FGL2 can fulfill an immunoregulatory role through its FRED at carboxyl end of the molecule and, and vice versa, whether s FGL2 is procoagulant upon binding to a target cell. Knowledge in this area should shed light on development of s FGL2 as an alternative immunosuppressive agent for organ transplantation or as a biomarker for predicting disease progression, monitoring therapeutic effects, and targeting FGL2 for repression in ameliorating fulminant viral hepatitis.

Reverse genetics: Unlocking the secrets of negative sense RNA viral pathogens

Negative-sense RNA viruses comprise several zoonotic pathogens that mutate rapidly and frequently emerge in people including Influenza, Ebola, Rabies, Hendra and Nipah viruses. Acute respiratory distress syndrome, encephalitis and vasculitis are common disease outcomes in people as a result of pathogenic viral infection, and are also associated with high case fatality rates. Viral spread from exposure sites to systemic tissues and organs is mediated by virulence factors, including viral attachment glycoproteins and accessory proteins, and their contribution to infection and disease have been delineated by reverse genetics; a molecular approach that enables researchers to experimentally produce recombinant and reassortant viruses from cloned cD NA. Through reverse genetics we have developed a deeper understanding of virulence factors key to disease causation thereby enabling development of targeted antiviral therapies and well-defined live attenuated vaccines. Despite the value of reverse genetics for virulence factor discovery, classical reverse genetic approaches may not provide sufficient resolution for characterization of heterogeneous viral populations, because current techniques recover clonal virus, representing a consensus sequence. In this review the contribution of reverse genetics to virulence factor characterization is outlined, while the limitation of the technique is discussed withreference to new technologies that may be utilized to improve reverse genetic approaches.

Gastric mucormycosis: A case report

Mucormycosis is a rare fungal infection which is largely diagnosed in immune-compromised patients. The infection can cause pulmonary, rhinocerebral, skin and soft tissue, central nervous system and gastrointestinal system. The gastrointestinal involvement is the rarest presentation, especially the stomach. We present a 38 years old HIV positive female seen in Steve Biko Academic Hospital with 2 wk history of cough, shortness of breath and lethargy. She was clinically found to be pale, pyrexial, dyspnoea and had severe oral thrush. Blood tests revealed hemoglobin of 6 g/dL CD4 count of 63 cells/uL. Chest X-ray showed multi-lobe pneumonia and gastroscopy confirmed esophageal candidiasis and nodular gastritis. She continued to deteriorate despite antibiotics, antifungal and antituberculous treatment. She developed upper gastrointestinal bleed on day 34, and gastroscopy showed a plaque like lesion in the stomach, histology of which confirmed mucormycosis. She improved on Amphotericin B but subsequently deteriorated and demised a few days later. These cases illustrate the occurrence of a rare fungal infection of the stomach and the poor mortality when diagnosis is delayed. Mucormycosis can co-exist with candidiasis and clinicians should have a high index of suspicion especially in patients not responding to appropriate treatment.

COVID-19 compared to other epidemic coronavirus diseases and theflu

Coronaviruses are among the largest group of known positive-sense RNA viruses with a wide range of animal hosts as reservoir. In the last two decades,newly evolved coronaviruses such as the severe acute respiratory syndrome coronavirus(SARS-CoV) which caused the infamous 2002 outbreak, the Middle East respiratory syndrome coronavirus(MERS-CoV) which caused an outbreak in 2012, and now the SARS-CoV-2 [responsible for the current coronavirus disease 2019(COVID-19)] have all posed notable threats to global public health.But, how does the current COVID-19 outbreak compare with previous coronaviruses diseases? In this review, we look at the key differences between SARS-CoV, MERS-CoV, and SARS-CoV-2, and examine challenges in determining accurate estimates of the severity of COVID-19. We discuss coronavirus outbreaks in light of key outbreak severity indicators including,disease fatality, pathogen novelty, ease of transmission, geographical range, and outbreak preparedness. Finally, we review clinical trials of emerging treatment modalities and provide recommendations on the control of COVID-19 based on the mode of transmission of the coronaviruses. We also recommend the development and use of a standardized predictive epidemic severity models to inform future epidemic response.

Regulation of fim genes in uropathogenic Escherichia coli

Uropathogenic Escherichia coli(UPEC)is the leading cause of urinary tract infections in women,causing significant morbidity and mortality in this population.Adherence to host epithelial cells is a pivotal step in the pathogenesis of UPEC.One of the most important virulence factors involved in mediating this attachment is the type 1 pilus(type 1 fimbria)encoded by a set of fim genes arranged in an operon.The expression of type 1 pili is controlled by a phenomenon known as phase variation,which reversibly switches between the expression of type 1 pili(Phase-ON)and loss of expression(Phase-OFF).Phase-ON cells have the promoter for the fimA structural gene on an invertible DNA element called fimS,which lines up to allow transcription,whereas transcription of the structural gene is silenced in Phase-OFF cells.The orientation of the fimS invertible element is controlled by two site-specific recombinases,FimB and FimE.Environmental conditions cause transcriptional and post-transcriptional changes in UPEC cells that affect the level of regulatory proteins,which in turn play vital roles in modulating this phase switching ability.The role of fim gene regulation in UPEC pathogenesis will be discussed.

Treatment of methicillin-resistant Staphylococcus aureus infections:Importance of high vancomycin minumum inhibitory concentrations

Staphylococcus aureus(SA) infections remain a major cause of morbidity and mortality despite the availability of numerous effective anti-staphylococcal antibiotics.This organism is responsible for both nosocomial and community-acquired infections ranging from relatively minor skin and soft tissue infections to life-threateningsystemic infections.The increasing incidence of methicillin-resistant strains has granted an increasing use of vancomycin causing a covert progressive increase of its minimum inhibitory concentration(MIC)(dubbed the MIC "creep").In this way,the emergence of vancomycinintermediate SA(VISA) strains and heteroresistantVISA has raised concern for the scarcity of alternative treatment options.Equally alarming,though fortunately less frequent,is the emergence of vancomycin-resistant SA.These strains show different mechanisms of resistance but have similar problems in terms of therapeutic approach.Ultimately,various debate issues have arisen regarding the emergence of SA strains with a minimum inhibitory concentration sitting on the superior limit of the sensitivity range(i.e.,MIC = 2 μg/mL).These strains have shown certain resilience to vancomycin and a different clinical behaviour regardless of vancomycin use,both in methicillin-resistant SA and in methicillin-sensitive SA.The aim of this text is to revise the clinical impact and consequences of the emergence of reduced vancomycin susceptibility SA strains,and the different optimal treatment options known.

Prosthetic joint infections-a clinico-microbiological perspective: Review article

Prosthetic joint infections(PJIs),although not very common,currently pose a very significant threat since they are associated with severe complications,high morbidity rates and substantial costs.PJIs are most commonly caused by Staphylococcus aureus and coagulase-negative staphylococci.The diagnosis of implant-associated infections is very challenging since no single routinely used laboratory or clinical test has been shown to demonstrate adequate results with respect to sensitivity,specificity and accuracy.In most cases,a sum of clinical signs and symptoms,histopathology,blood tests,radiography,bone scans and microbiological testing is considered to arrive at an accurate diagnosis.Treatment of PJIs is also very difficult since most of the infections are caused by biofilm-producing microorganisms which are significantly more resistant to the hosts natural defense mechanisms and antibiotic treatment.For successful management,a combination of both antibiotic and surgical treatment is most often required,and early diagnosis is of the utmost importance.Thus,a multidisciplinary approach is potentially the best option in dealing with PJI,and should include the involvement of microbiologists,orthopedic specialists,clinicians,pathologists and radiologists in order to improve decision-making processes and ensure overall success.The following review aims at briefly outlining the microbiology,diagnostic and treatment options,and preventive measures associated with such infections.

GadE regulates fliC gene transcription and motility in Escherichia coli

BACKGROUND Escherichia coli(E.coli)express flagella to ascend human urinary tracts.To survive in the acidic pH of human urine,E.coli uses the glutamate decarboxylase acid response system,which is regulated by the GadE protein.AIM To determine if growth in an acidic pH environment affected fliC transcription and whether GadE regulated that transcription.METHODS A fliC-lacZ reporter fusion was created on a single copy number plasmid to assess the effects of acidic pH on fliC transcription.Further,aΔgadE mutant strain of a uropathogenic E.coli was created and tested for motility compared to the wildtype strain.RESULTS Escherichia coli cells carrying the fliC-lacZ fusion displayed significantly less fliC transcription when grown in an acidic pH medium compared to when grown in a neutral pH medium.Transcription of fliC fell further when the E.coli was grown in an acidic pH/high osmolarity environment.Since GadE is a critical regulator of one acid response system,fliC transcription was tested in a gadE mutant strain grown under acidic conditions.Expression of fliC was derepressed in the E.coli gadE mutant strain grown under acidic conditions compared to that in wild-type bacteria under the same conditions.Furthermore,a gadE mutation in a uropathogenic E.coli background exhibited significantly greater motility than the wild-type strain following growth in an acidic medium.CONCLUSION Together,our results suggest that GadE may down-regulate fliC transcription and motility in E.coli grown under acidic conditions.

Disseminated cryptosporidiosis:Case report and literature review

Cryptosporidiosis,better known as an intestinal disease may disseminate to infect other sites including the respiratory tract. Little information however is available on respiratory cryptosporidiosis that may largely be due to lower frequency of respiratory cryptosporidiosis. Respiratory cryptosporidiosis has been majorly reported in immunocompromised individuals and children. Here we report a case of respiratory and intestinal cryptosporidiosis in a fifteen months old child with CD8+ deficiency. The patient in spite of treatment with Nitazoxanide and Azithromycin followed by Intravenous immunoglobulin and Bovine colostrum had a fatal outcome. The Cryptosporidium spp. isolate was subjected to molecular characterization. The Cryptosporidium spp. was identified both in stool specimen and Endotracheal aspirate(ETA). The blood sample was negative for Cryptosporidium spp. The Cryptosporidium spp. isolate from stool as well as ETA was identified as Cryptosporidium hominis(C. hominis) using Multiplex Allele Specific Polymerase Chain Reaction assay and was subtyped as Ia A23G1R1 subtype using gp60 gene polymerase chain reaction assay followed by sequencing.

Osmolyte transport in Staphylococcus aureus and the role in pathogenesis

Osmolyte transport is a pivotal part of bacterial life, particularly in high salt environments. Several low and high affinity osmolyte transport systems have been identified in various bacterial species. A lot of research has centered on characterizing the osmolyte transport systems of Gram-negative bacteria, but less has been done to characterize the same transport systems in Gram-positive bacteria. This review will focus on the previous work that has been done to understand the osmolyte transport systems in the species Staphylococcus aureus and how these transporters may serve dual functions in allowing the bacteria to survive and grow in a variety of environments, including on the surface or within humans or other animals.

COVID-19,stigma,and people with disabilities:A mental health perspective

Discrimination is an age-old‘illness’irrespective of its context.Stigma is a common factor that has been associated with disability and coronavirus disease 2019.The public health impact of stigma on differently-abled people during this pandemic is not known and it is a poorly investigated and neglected area.It is important to address the current research need in the concerned area and its implications for public health policymaking and changes in practices that it requires.Together we can win the war against pandemics if we reduce the mental distancing in all perspectives.

Extended role for insertion sequence elements in the antibiotic resistance of Bacteroides

The Bacteroides species are important micro-organisms, both in the normal physiology of the intestines and as frequent opportunistic anaerobic pathogens, with a deeply-rooted phylogenetic origin endowing them with some interesting biological features. Their prevalence in anaerobic clinical specimens is around 60%-80%, and they display the most numerous and highest rates of antibiotic resistance among all pathogenic anaerobes. In these antibiotic resistance mechanisms there is a noteworthy role for the insertion sequence(IS) elements, which are usually regarded as representatives of ‘selfish' genes; the IS elements of Bacteroides are usually capable of up-regulating the antibiotic resistance genes. These include the cep A(penicillin and cephalosporin), cfx A(cephamycin), cfi A(carbapenem), nim(metronidazole) and erm F(clindamycin) resistance genes. This is achieved by outwardoriented promoter sequences on the ISs. Although some representatives are well characterized, e.g., the resistance gene-IS element pairs in certain resistant strains, open questions remain in this field concerning a better understanding of the molecular biology of theantibiotic resistance mechanisms of Bacteroides, which will have clinical implications.