Characterization of virulence factors and antibiotic resistance pattern of uropathogenic Escherichia coli strains in a tertiary care center.

Background: Urinary tract infections (UTI) are the most prevalent bacterial infection in humans. The uropathogenic E. coli (UPEC) expresses a range of virulence factors that contribute to their pathogenicity . The emergence of multidrug resistance (MDR)-associated UTI is increasing. This study monitors the distribution of virulence factors among UPEC strains to note the antibiogram, outcome and type of associated UTI. Methods: A prospective cross-sectional time-bound study of six months was done on clinically significant urinary isolates of Escherichia coli. Detection of haemolysin production and serum resistance was done by phenotypic methods. Genotypic characterization of the virulence genes ( papC, iutA, hlyA, cnf1) was done by multiplex PCR. Demographic data, clinical history, antibiogram and type of UTI was collected from clinical case records. Results:75 E.coli isolates from patients with suspected UTIs were included. Females had a higher preponderance of UTI (66.7%). 93% of patients were adults and the remaining 7% were from paediatrics.  24 (32%) isolates showed haemolysis by plate haemolysis and all isolates were serum-resistant. Out of 75 isolates, 65 were positive for at least one of four targeted genes, while remaining ten isolates were negative for all four genes. Multidrug resistance was found in 40 (53.3%) isolates. 97.4% of the UTI cases had a favourable clinical outcome at discharge. Mortality due to urosepsis was 2.6%. Conclusion: Association of hemolysin production with resistance to imipenem and norfloxacin in UPEC strains was significant. Presence of hlyA gene is positively associated with ceftazidime resistance. Nitrofurantoin, piperacillin, tazobactam, and cefaperazone sulbactam are possible candidates for empirical therapy of UTIs. Drugs like aminoglycosides, carbapenems and fosfomycin may be used as reserve drugs in the treatment of MDR-UTI. However, inappropriate usage can increase antibiotic resistance. Hence proper selection of antibiotics in hospitals taking into account the local antibiogram is needed to reduce the emergence of antibiotic resistance.

Genotypic and Phenotypic Expression of Antibiotic Resistance Patterns of Uropathogenic Enterobacteriaceae.

Aim: To determine the antibiotic resistance patterns, detection of carbapenemase genes in uropathogenic bacilli belonging to the Enterobacteriaceae family and to correlate it with clinical data. Materials and Methods: Identification and antibiotic sensitivity testing of the uropathogenic Enterobacteriaceae was done by using VITEK2 Compact (C) system. Multiplex PCR was used to detect blaIMP, blaKPC, blaNDM1, blaOXA -48, and blaVIM genes. Results: Out of 1602 urine samples, 417 (26%) showed significant growth, and in these 311 (74.6%) belonged to the Enterobacteriaceae family. Escherichia coli showed a relatively low rate of resistance to nitrofurantoin (17/205; 8.3%), with the majority of the isolates showing a MIC value of ≤16 µg/mL when compared to Klebsiella spp. (55/86; 64%), with MIC values for the majority of isolates being 128 µg/mL. Klebsiella spp. showed a relatively low rate of resistance to nalidixic acid (48/86; 55.8%) when compared with E. coli isolates (179/205; 87.3%). Out of 145 isolates tested, we found blaNDM in 11 (7.58%), bla OXA -48 in 8 (5.51%), bla VIM in 4 (2.75%), bla KPC in one (0.6%) and blaIMP in none of the isolates. Of these 3 isolates were carbapenem sensitive, the rest were resistant. Conclusion: Most of the isolates were sensitive to fosfomycin, carbapenems and resistant to cephalosporins and nalidixic acid. We detected carbapenemase genes in 13 (59%) out of 22 carbapenem resistant isolates and 3 (2.4%) out of 123 carbapenem sensitive isolates.

Carnosic Acid as an intracanal medicament performs better than triple antibiotic paste and calcium hydroxide to eradicate Enterococcus faecalis from root canal: An in vitro confocal laser scanning microscopic study.

Background: Carnosic acid is an herbal derivative with potent antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. Aim: Comparative evaluation of the antimicrobial potential of carnosic acid, calcium hydroxide, and triple antibiotic paste as intracanal medicaments against Enterococcus faecalis. Settings and Design: Department of Conservative Dentistry and Microbiology, an in vitro study. Materials and Methods: Fifty-two extracted single-rooted human teeth were decoronated and chemomechanical preparation was performed. The specimens were secured in the center of screw-capped vials and autoclaved. A strain of E. faecalis was inoculated into the canals and grown for 72 h. The teeth were divided into: Group I-Ca(OH)2, Group II- triple antibiotic paste (TAP), Group III-Carnosic acid, and Group IV-Negative control. The medicaments were applied in the canal and left for 14 days. The specimens were sectioned transversely at three levels to create dentinal discs and observed under the confocal laser scanning microscopic (CLSM). Images were analyzed, and quantification of bacteria was done using the Image J software. Statistical Analysis: Mean percentage of live/dead bacteria was analyzed using One-way ANOVA and Post hoc Tukey test. Results: Mean percentages of live and dead bacteria were seen under CLSM in Group I, Group II, and Group III were (4.44 ± 2.87, 4.56 ± 2.93, 1.61 ± 1.90), and (4.59 ± 3.04, 4.25 ± 2.98, 1.70 ± 1.99), respectively, with least mean percentages for live and dead bacteria in carnosic acid (Group III). Conclusion: Carnosic acid showed better antimicrobial efficacy against E. faecalis than TAP and Ca(OH)2 by showing a low percentage of both live and dead bacteria.

Microbial assessment of dental unit waterlines in an institutional setup in Karnataka, South India.

BACKGROUND AND AIM: Biofilms in dental unit waterlines (DUWLs), suction hoses, and fittings are a potentially significant source of cross-contamination posing significant health risk as these may come into contact with patients during treatment. The purpose of this in vitro study was to identify the spectrum of bacterial flora colonizing the DUWLs and to detect pathogenic microorganisms present in such an environmental niche. MATERIALS AND METHODS: Thirty DUWL samples were collected from in use dental units selected randomly from various clinical departments. Samples were collected from the following devices; 3-in-1 syringe waterline, section of waterline tubing supplying the 3-in-1 syringe, and the air rotor water. The samples were subjected to bacteriological analysis, and all bacterial isolates were tested for their ability to form biofilms. RESULTS: A descriptive analysis of the results obtained was carried out, and it was observed that 7 out of 30 (23.3%) samples collected from DUWL were supplying water of unsatisfactory quality with species of low-pathogenicity bacteria isolated present in significant numbers; four of ten (40%) water supply lines contained bacterial biofilms; and the species with greatest capability to form biofilms were Enterobacter species (spp.). In addition, the results were also subjected to Chi-square test which revealed no statistical difference between the species and the location of collection of samples. CONCLUSION: Within the limitations of this study, it is concluded that DUWLs are not totally free of contamination. Microbial biofilms are a significant source of cross-contamination and cross-infection in the dental clinic environment.

Molecular characterisation of uropathogenic Escherichia coli isolates at a tertiary care hospital in South India.

Uropathogenic Escherichia coli (UPEC) express a multitude of virulence factors (VFs) to break the inertia of the mucosal barrier of the urinary tract. The aim of the present study was undertaken to characterised the UPEC strains and to correlate carriage of specific virulence markers with different phylogroups and also to correlate these findings with clinical outcome of patients. A total of 156 non-repeated, clinically significant UPEC isolates were studied. Virulent genes were determined by two set of multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Antibiograms and patient's clinical outcomes were collected in a structured pro forma. Of the 156 patients infected by UPEC strains with significant bacterial counts the most common predisposing factors were diabetes (45.5%) followed by carcinoma (7%). On analysis of the VF genes of the isolates, a majority of strains (140; 90%) were possessing the fimH gene followed by iutA (98; 63%), papC (76; 49%), cnf1 (46; 29.5%), hlyA (45; 29%) and neuC (8; 5%), respectively. On phylogenetic analysis, 27 (17%) isolates were belong to phylogroup A, 16 (10%) strains to Group B1, 59 (38%) were from Group B2 and 54 (35%) were from Group D. High prevalence of antibiotic resistance was observed among the isolates. The incidence of papC, cnf1 and hlyA was significantly higher (P < 0.05) among the isolates from relapse patients. Our findings indicate that virulent as well as commensal strains are capable of causing urinary tract infection. Virulence genes as well as patients-related factors are equally responsible for the development of infections and also that virulence genes may help such isolates to persist even with appropriate chemotherapy and be responsible for recurrent infections.

A Fortuitous Turn of Evidence in an Elderly Female - A Case of Pulmonary Fusariosis.

Pulmonary mycosis is seen infrequently in our country. It is more common in the immunocompromised. The infections caused by less known species like Fusarium have been found to be increasing in incidence in other parts of the world. We hereby report its occurrence in a 79-year-old, non-immunocompromised female who presented with pyrexia of unknown origin. Her Alanine Phosphatase (ALP) and Lactate Dehydrogenase (LHD) levels were raised. CT scan showed interstitial thickening in subpleural aspect of lungs and multiple enlarged lymph nodes in mediastinum. Liver showed multiple hypodense lesions. Metastasis was suspected for which Fine Needle Aspiration Cytology (FNAC) of liver was done which showed foci of regenerative hepatocytes with desmoplastic stromal tissue fragments and negative for tumour. Her Alpha Fetoprotein (AFP) was normal. The bronchial tree cytology showed endobronchial cells, dust-laden macrophages and chronic inflammatory cells along with fungi on Pap smear studies. This was confirmed by culture that grew Fusarium species. after one week of incubation. The acutely branching septate hyphae of Fusarium species are identical to those of Aspergillus species. In a patient who has a disseminated infection with a septate fungus, growth in culture is important to identify the specific organism and subsequently treatment with appropriate antifungals. In cases like ours, where the infection simulates malignancy, it is even more important to make the correct diagnosis to give the appropriate treatment.

Is diabetes mellitus an important risk factor for the antibiotic resistance in extraintestinal pathogenic Escherichia coli?

Escherichia coli is a major cause of extraintestinal infections in all age group. However, the infection becomes more severe when patients have some underlying condition such as Diabetes Mellitus. The aim of the study was to determine whether diabetic mellitus may act as an important risk factor for the E. coli to express drug resistance property. This descriptive study was carried out in a multi-specialty tertiary care hospital. One hundred and twenty-seven E. coli isolates from diabetic patients, and one hundred seventy-three isolates from nondiabetic patients were studied. Possession drug resistance genes were determined by multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR. Antibiotic sensitivity testing was performed by Kirby-Bauer disk diffusion method. Among the study isolates from Diabetic patients maximum numbers were from phylogroup B2 (42.5%) and D (33%) similarly in case of nondiabetic patients B2 (29%) and D (38%) were the most common phylogroup. Presence of drug resistance genes among the diabetic and nondiabetic patient's isolates were as followed extended-spectrum beta-lactamase (70% and 70.5%) AmpC (9.5% and 14.5%) and NDM-1 ( 7% and 4.5%) and by disk diffusion methods susceptibility pattern were meropenem (94% and 94%), imipenem (92% and 92%), amikacin (76% and 74%), and ampicillin/sulbactam (68% and 69%), respectively. The proportion of diabetic patients strains with the drug resistance characteristics were not significantly different from that seen in nondiabetic patients strains, which indicating that in a predisposed host additional or subtraction bacterial aids for drug resistance property are not a necessity.

Virulence factor profiles, phylogenetic background, and antimicrobial resistance pattern of lactose fermenting and nonlactose fermenting Escherichia coli from extraintestinal sources.

CONTEXT: In recent years, nonlactose fermenting (NLF) Escherichia coli have been increasingly isolated in the microbiology laboratory, but their clinical significance has not yet been clearly elucidated. AIMS: To characterize the lactose fermenting (LF) and NLF isolates on the basis of their virulence factors, phylogenetic background, and drug resistance property. SETTINGS AND DESIGN: This descriptive study was carried out in a multi-specialty tertiary care hospital. SUBJECTS AND METHODS: Three hundred nonrepeat E. coli isolates from inpatients were studied. Isolates were differentiated as LF and NLF on the basis of colony characteristics on MacConkey's agar. Possession of virulence and drug resistance genes was determined by multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Antibiotic sensitivity testing was performed by disk diffusion method. RESULTS: Of 300 isolates 39 (13%) were NLF isolates. Maximum number of NLF isolates belonged to phylogroups B2 and D when compared with LF isolates. The incidence of iutA, hlyA, and neuC genes were significantly higher in NLF isolates. The presence of drug resistance genes such as AmpC gene, SHV, and CTXM were higher in LF isolates. CONCLUSIONS: LF isolates demonstrated a higher antimicrobial resistance and NLF isolates possessed higher virulence properties. The microbiology laboratory should report lactose fermentation profile as it may help the physician to initiate appropriate treatment.

Molecular characterization and clinical significance of New Delhi metallo-beta-lactamases-1 producing Escherichia coli recovered from a South Indian tertiary care hospital.

CONTEXT: The increased rate of infection by New Delhi metallo-beta-lactamases-1 (NDM1) producing Escherichia coli is a major concern since they show a high rate of drug resistance and are responsible for mortality and morbidity. AIMS: To characterize the NDM1 producing E. coli isolates and their impact on patients' clinical outcome. SETTINGS AND DESIGN: This descriptive study was carried out in a multi-specialty tertiary care hospital. MATERIALS AND METHODS: Three hundred nonrepeat strains of E. coli from inpatients were included in the study. Modified Hodge test and metallo-beta-lactamases (MBL) e-test were performed to detect carbapenemase and MBL activity. Polymerase chain reaction (PCR) technique was performed to detect NDM1. NDM1 positive isolates were further tested for plasmid mediated AmpC, blaCTX , blaSHV , blaTEM genes and also for phylogrouping by PCR methods. Treatment and patients' clinical outcome were also analyzed. RESULTS: Out of 300 isolates, 21 (7%) were MBL producers by phenotypic methods. Of this, 17 (81%) were NDM1 positives, among the NDM1 producers 6 (35%) isolates were belongs to phylogroups D followed by A 5 (29%), B1 4 (24%) and B2 2 (12%), 15 (88%) isolates were blaCTX-M positive suggestive of extended-spectrum beta lactamase producing strain and 7 (47%) were positive with CIT type of AmpC. With the follow-up of the patients, it was found that 12 (71%) recovered and 3 (18%) developed relapses, and mortality was seen in 2 (12%) patients. CONCLUSIONS: NDM1 producing isolates showed a high degree of drug resistance but can be treated with suitable antimicrobials, in the majority. Early detection and choice of appropriate antibiotics may help in reducing mortality and morbidity.

Genomic analysis and clinical importance of Escherichia coli isolate from patients with sepsis.

CONTEXT: Escherichia coli is a major cause of bloodstream infections and death due to sepsis. Bacteremic isolates harbor a significantly greater repertoire of virulence factors (VFs) in contrast with commensal E. coli isolates. AIMS: The aim was to determine the relationships between E. coli VFs, phylogenetic groups, and their clinical importance. SETTINGS AND DESIGN: This descriptive study was carried out in a multi-specialty tertiary care hospital. MATERIALS AND METHODS: Escherichia coli isolates from consecutive episodes of bacteremia in 100 patients were screened for their VFs, phylogenetic group, and their effect on patient's clinical outcome. Virulence genes of all isolates were determined by multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Estimation of risk of death was calculated using APACHE score II calculator. RESULTS: Of the 100 patients, the most common predisposing factors were diabetes (42%), followed by carcinoma (23%). On analysis of the VF genes of the isolates, a majority of strains (88%) were possessing the fimH gene followed by iutA (76%), papC (44%), cnf1 (16%), hlyA (16%) and neuC (5%) respectively. Phylogenetic analysis revealed that 25 (25%) isolates belonged to phylogroup A, 8(8%) strains to group B1, 30 (30%) were from group B2 and 37 (37%) were from group D. The incidence of iutA gene was significant in higher APACHE II score group. CONCLUSIONS: Our findings indicate that virulent as well as commensal strains are capable of causing sepsis. Host related predisposing factors, adherence factors, and iron uptake are essential for the survival of the sepsis inducing strains.

Clinical significance and phylogenetic background of extended spectrum ß-lactamase producing Escherichia coli isolates from extra-intestinal infections.

INTRODUCTION: Escherichia coli producing extended spectrum-ß-lactamases (ESBL), particularly CTX-M type ESBLs, have rapidly spread worldwide and pose a serious threat for healthcare-associated infections. We performed a molecular detection and characterization study of ESBL-related bla genes, including blaTEM, blaSHV, blaCTX-M, and blaCTX-M15, and also assessed the relationship between the phylogenetic background of strains carrying ESBL genes and the patient's clinical outcome. METHODOLOGY: A total of 300 non-repeated, clinically significant isolates were investigated. The molecular types of ESBL genes were determined using multiplex PCR. Phylogenetic analysis was performed using triplex PCR methods. Antibiograms and the patient's clinical outcome were collected in a structured pro forma. RESULTS: Among the 300 isolates, 212 (70.5%) isolates were found to carry ESBL genes. A total of 186 (62%) strains were positive for the blaCTX-M gene, and 171 isolates (approximately 92%) of these blaCTX-M producers were positive for blaCTXM-15. Phylogenetic analysis of the isolates indicated that 41 (67%) Group A, 22 (81.50%) group B1, 67 (64.5%) group B2 and 82 (76%) group D isolates carried different ESBL genes. Appropriate antibiotic therapy helped to resolve infection in 66.5% patients. CONCLUSION: Our study documented the high prevalence of ESBLs in E. coli isolates, with CTX-M-15 as the predominant ESBL gene in the region, and these isolates predominantly belonged to commensal phylo-groups. Thus, an appropriate antibiotic and hospital policy is required to reduce the horizontal spread of ESBL genes among various bacterial strains, whereas in the near future, the spread of ESBL producers may result in therapeutic dead ends.

Characterization of plasmid mediated AmpC producing Escherichia coli clinical isolates from a tertiary care hospital in South India.

CONTEXT: Plasmid mediated AmpC (pAmpC) ß-lactamase producing Escherichia coli are an emerging problem worldwide as they are now exhibiting resistance to multiple classes of antibiotics and are a major cause of therapeutic failure. AIMS: The aim of this study was to characterize pAmpC ß-lactamase producing extraintestinal E. coli, their phylogenetic distribution, resistance pattern, treatment options, and impact on patient's clinical outcome. SETTINGS AND DESIGN: This descriptive study was carried out in a multi-specialty tertiary care hospital. MATERIALS AND METHODS: A total of 300 clinically significant, non-repeat isolates were studied. AmpC disk test was used for phenotypic AmpC-ß-lactamase detection. Molecular types of pAmpC were determined by a multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Metallo-beta-lactamase (MBL) detection was done by E test. Antibiogram, treatment, and clinical outcome were collected in a structured proforma. RESULTS: Although 95 isolates (32%) were phenotypically positive for AmpC, PCR detected CIT type of AmpC gene in only 37 isolates. Majority of strains were from phylogroup A (85%) and B1 (58%) which are considered as commensal groups. Co-production of ESBL's was observed in 33 strains and 5 strains were found to be MBL producers. Most widely prescribed antibiotics were 3 rd generation cephalosporins (30%), carbapenems (19%) and aminoglycosides (16%). CONCLUSIONS: Plasmid mediated AmpC producing isolates were found to exhibit a high degree of drug resistance, and they mainly belonged to commensal strains possibly due to misuse of antibiotics. Proper antibiotic policy is required to limit the spread of pAmpC producers or else it will lead to a therapeutic dead end in the near future.

Effect of phenotypic switching on expression of virulence factors by Candida albicans causing candidiasis in diabetic patients

Se aislaron 110 cepas que pertenecían a siete especies de Candida procedentes de pacientes diabéticos con distintas formas de candidiasis, encontrándose 53 aislamientos de Candida albicans (47%), 36 de Candida tropicalis (33%), 9 de Candida glabrata (8%), 4 de Candida parapsilosis (4%), 2 de Candida guilliermondii (2%), 5 de Candida krusei (5%) y 1 de Candida kefyr (1%). En las 53 cepas de C. albicans aisladas se estudió la expresión de factores de virulencia tales como la hidrofobicidad de la superficie celular (CSH), adherencia a células epiteliales bucales humanas (BEC) y actividad enzimática. La actividad proteolítica se detectó en el 100% de las cepas de C. albicans, mientras que la producción de fosfolipasa se detectó en 52 cepas (98%). Se estudió la variación fenotípica y su influencia en factores de patogenicidad en dos cepas de C. albicans, procedentes de boca y vagina respectivamente, y en la cepa patrón C. albicans NCPF 3153A. Se les indujo la variación fenotípica mediante exposición a luz UV y se valoró el grado de expresión de los factores de virulencia por las diversas formas morfológicas obtenidas. Se obtuvieron tres variaciones morfológicas de C. albicans: forma de estrella (S), rugosa (W) y anular (R), a partir de la variedad lisa original (O). La actividad proteinasa fue mayor en el tipo W, seguida por el tipo R, y por el tipo O; el tipo S fue el de menor actividad proteolítica. La actividad fosfolipasa fue mayor en el tipo O, seguida por el tipo R; los tipos W y S presentaron una actividad fosfolipasa menor. La expresión de la CSH y de la adherencia fue superior en el tipo O, seguida por el tipo R y el tipo W, y finalmente el tipo S. Las variaciones fenotípicas de C. albicans presentan una expresión diferenciada de factores de virulencia y ello puede proveer a un tipo morfológico particular de ciertas ventajas, facilitando el inicio de una candidiasis(AU)

A total of 110 strains belonging to seven species of Candida were isolated from various forms of candidiasis in diabetic patients. They were Candida albicans 53 (47%), Candida tropicalis 36 (33%), Candida glabrata 9 (8%), Candida parapsilosis 4 (4%), Candida guilliermondii 2 (2%), Candida krusei 5 (5%) and Candida kefyr 1 (1%). All 53 strains of C. albicans isolated were observed to express virulence factors such as cell surface hydrophobicity (CSH), adherence to human buccal epithelial cell (BEC) and proteinase activity (100%), while phospholipase activity was observed in 52 (98%). Phenotypic switching and its influence on the pathogenicity of C. albicans were studied. Two C. albicans strains isolated from oral and vaginal thrush, respectively, in diabetic individuals, and the control strain C. albicans NCPF 3153A were induced to undergo phenotypic switching by exposure to UV light and the degree of expression of virulence factors by the different morphological forms was determined. Three different morphological forms of C. albicans were obtained, namely Star (S), Wrinkled (W) and Ring (R) types from the original Smooth (O) variety. It was found that proteinase activity was greatest with the W type followed by the R type then the O type. The S type produced the least proteinase. The phospholipase activity was greatest with O type followed by R type. The W and S types produced the least phospholipase. Expression of CSH and adherence was greatest in the O type followed by the R and then the W type and finally the S type. Differential expression of virulence factors occurs with different phenotypic forms of C. albicans and this may provide a particular morphological type with a distinct advantage over other types in causing candidiasis(AU9

Effect of phenotypic switching on expression of virulence factors by Candida albicans causing candidiasis in diabetic patients.

A total of 110 strains belonging to seven species of Candida were isolated from various forms of candidiasis in diabetic patients. They were Candida albicans 53 (47%), Candida tropicalis 36 (33%), Candida glabrata 9 (8%), Candida parapsilosis 4 (4%), Candida guilliermondii 2 (2%), Candida krusei 5 (5%) and Candida kefyr 1 (1%). All 53 strains of C. albicans isolated were observed to express virulence factors such as cell surface hydrophobicity (CSH), adherence to human buccal epithelial cell (BEC) and proteinase activity (100%), while phospholipase activity was observed in 52 (98%). Phenotypic switching and its influence on the pathogenicity of C. albicans were studied. Two C. albicans strains isolated from oral and vaginal thrush, respectively, in diabetic individuals, and the control strain C. albicans NCPF 3153A were induced to undergo phenotypic switching by exposure to UV light and the degree of expression of virulence factors by the different morphological forms was determined. Three different morphological forms of C. albicans were obtained, namely Star (S), Wrinkled (W) and Ring (R) types from the original Smooth (O) variety. It was found that proteinase activity was greatest with the W type followed by the R type then the O type. The S type produced the least proteinase. The phospholipase activity was greatest with O type followed by R type. The W and S types produced the least phospholipase. Expression of CSH and adherence was greatest in the O type followed by the R and then the W type and finally the S type. Differential expression of virulence factors occurs with different phenotypic forms of C. albicans and this may provide a particular morphological type with a distinct advantage over other types in causing candidiasis.

Prevalence of opportunistic infections in AIDS patients in Mangalore, Karnataka.

A study was conducted to determine the prevalence of opportunistic infections in HIV-seropositive patients at Kasturba Medical College Hospital, Mangalore. Three hundred and seven HIV-positive patients were screened for various opportunistic pathogens. Tuberculosis was the most common infection followed by candidiasis, cryptosporidiosis and cryptococcal meningitis.

Effect of trace elements on surface hydrophobicity and adherence of Escherichia coli to uroepithelial cells.

Trace elements have significant effect on the physiology of bacteria. Variation in the concentration of trace elements may affect the expression of virulence by microorganisms. The effect of trace elements on hydrophobicity and adherence of E.coli to uroepithelial cells was studied. Increasing concentrations of Ca2+, Mg2+, Fe3+ and Zn2+ significantly decreased the surface hydrophobicity. Toxic trace elements like Co2+, Cu2+, Mn2+ and Ni2+ did not alter surface hydrophobicity. With regards to adherence of E.coli to uroepithelial cells, only Mg2+ had significant effect. Toxic trace elements decreased the rate of cell adherence. The pathogenic strains of E.coli showed higher surface hydrophobicity and better cell adherence compared to the nonpathogenic strains. There was good correlation between surface hydrophobicity and cell adherence at higher concentrations (0.1 to 0.2mM) of Fe2+ and Zn2+. The results indicated that trace elements can significantly affect surface hydrophobicity and adherence of E.coli to uroepithelial cells. Such effect may have a significant impact on the initial stages of bacterial infection.