The Journal of Infection in Developing Countries

Development of modified diagnostic criteria for bacterial vaginosis at peripheral health centres in developing countries

Vineeta Mittal, Amita Jain, Yashodhara Pradeep — Wed, 30 Nov 2011 01:48:44 -0800

Introduction: Bacterial vaginosis (BV) is the commonest cause of abnormal vaginal discharge in women of child-bearing age and is associated with increased susceptibility to HIV-AIDS and sexually transmitted diseases. In obstetrics, BV has been implicated in causing various complications. In clinical practice, BV is diagnosed using Amsel criteria and Nugent scoring. Using modified Amsel criteria, we determined that the fulfilling of any two instead of three criteria can be diagnostic of BV.

Methodology: This prospective cross-sectional study involved pregnant females complaining of excessive vaginal discharge admitted in a tertiary health centre in central India. Four vaginal swabs were collected for the diagnosis of BV by Amsel criteria, modified Amsel criteria, and Nugent scoring on Gram stain. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of each individual criterion and combinations of criteria were calculated by using Nugent scoring as the gold standard and by chi square test.

Results: In the present study overall prevalence of BV was 12%. The sensitivity of individual or a combination of two criteria was almost same or higher than that of Amsel criteria. Specificity of each combination of criteria was comparable to that of Amsel criteria. However, a combination of high pH and amine odor test had the highest sensitivity (88%) and highest PPV (62%). Diagnostic accuracy of all combinations in our study was equal to or slightly higher than that of Amsel criteria.

Conclusion: Diagnostic accuracy of new modified Amsel criteria is as reliable as that of Amsel criteria.

Risk factors for Shiga toxin-producing Escherichia coli infections in preadolescent schoolchildren in Buenos Aires, Argentina

Wed, 30 Nov 2011 03:18:29 -0800

Introduction: Shiga toxin-producing Escherichia coli (STEC) infections are the leading cause of hemolytic uremic syndrome (HUS). STEC is the most common cause of acute kidney disease, responsible for 20% of renal transplants in Argentina.

Methodology: In 2007, an epidemiological survey was conducted among 883 students from the fifth and sixth years of elementary education in the public schools of San Martin City, Buenos Aires, Argentina. Degree of exposure to the known risk factors previously detected in the region as primary causes of STEC infections was evaluated. Risk factors assessed included consumption of hamburgers, poor personal hygiene, and exposure to various types of drinking and recreational water. The study was designed to evaluate exposure to risk factors for STEC infections among different socioeconomic groups.

Results: Ninety-five percent of children surveyed reported consumption of hamburgers. Most of these hamburgers were precooked. Children of high and medium strata attended private swimming-pools, while children from the low stratum attended public pools. Only 30.2% of students washed their hands after going to the toilet and only 43.5% reported hand-washing before eating.

Conclusions: Students demonstrated high levels of exposure to identified risk factors for STEC infections. Reduction of these risks will require cultural changes aimed at decreasing morbidity caused by food-borne infections. Institutional framework must provide the necessary resources to implement these changes and emphasize the importance of good personal hygiene. Health education must be implemented to increase food safety awareness of the consumers.

A retrospective study of community-acquired Salmonella infections in patients attending public hospitals in Lagos, Nigeria

Wed, 30 Nov 2011 10:31:01 -0800

Introduction: A retrospective cohort study on Salmonella-associated diseases (SADs) was conducted in 14 public hospitals across Lagos State, Nigeria, between 1999 and 2008.

Methodology: Medical records of clinically diagnosed patients with confirmed Salmonella infections were reviewed for the 10-year period. Laboratory diagnosis of typhoid fever cases in all the hospitals were first based on Widal agglutination tests then followed by culture, while non-typhoidal Salmonella infections were based on culture technique.

Results: A total of 85,187 confirmed cases of SADs were found, of which 880 deaths were recorded (case-fatality rate = 1.03% / 10 years). The mean incidence of SADs in Lagos State for the 10-year period was estimated at 45 cases per 100,000 persons/year, while that of typhoid fever alone was 16 cases per 100,000 persons/year. During the studied period, the number of deaths due to typhoid fever was significantly (P < 0.05) higher than deaths due to gastroenteritis except in 2003 and 2004. Risk associated with typhoidal deaths was 4 to 11 times greater when compared to gastroenteritis deaths between 2000 and 2002. Salmonella-associated diseases were most prevalent in adults 21 -to30 years of age (49.49%). Cases of patients with invasive Salmonella-associated gastroenteritis were observed mainly in children under five years of age.

Conclusion: The current surveillance data indicated high incidence of SADs in areas exposed to environmental contaminations. This study revealed that infections caused by Salmonella enterica serovars are endemic in our environment thus poses a serious threat to public health. Constant public health education is essential to avert undue epidemics.

Comparison of four serological assays for the diagnosis of Chlamydia trachomatis in subfertile women

Wed, 30 Nov 2011 02:04:06 -0800

Introduction: Chlamydia antibody testing (CAT) in serum has been introduced as a screening method in the infertility workup. We evaluated the test characteristics of two ELISA tests compared to micro-immunofluorescence tests (MIFs). MIFs are considered the gold standard in the C. trachomatis IgG antibodies detection. We also compared the accuracy of all CAT tests in predicting tubal subfertility, using laparoscopy as a reference.

Methodology: Four commercial serological methods were used to analyse 101 serum samples for the presence of C. trachomatis IgG antibodies from patients at the Infertility Clinic of Ghent University Hospital. The diagnostic utility for prediction of tubal infertility of serological methods was evaluated based on patients' medical records.

Results: A comparison of the serological assays showed little difference in the major performance characteristics: the sensitivities of all MIFs and ELISAs were 100% for all assays (except the ELISA Vircell, with a sensitivity of 90%), and the specificities ranged from 92% for MIF Ani Labsystems to 98% for the MIF Focus and ELISA Vircell. As compared to laparoscopy data, CAT positivity in subfertile women with tubal damage (n=40) did not significantly differ from that of subfertile women without tubal damage (n=61): Positive predictive values (PPV) of CAT ranged from 53% to 60% and negative predictive values (NPV) ranged from 62% to 64%.

Conclusion: evaluated ELISAs are comparable to MIFs in the detection of C. trachomatis IgG antibodies and should be preferred for large serological studies, especially in resource poor settings.

Study on biofilm-forming properties of clinical isolates of Staphylococcus aureus

Yasmeen Taj, Farhan Essa, Faisal Aziz, Shahana Urooj Kazmi — Tue, 13 Dec 2011 10:56:06 -0800

Introduction: The purpose of this study was to observe the formation of biofilm, an important virulence factor, by isolates of Staphylococcus aureus (S. aureus) in Pakistan by different conventional methods and through electron microscopy.

Methodology: We screened 115 strains of S. aureus isolated from different clinical specimens by tube method (TM), air-liquid interface coverslip assay method, Congo red agar (CRA) method, and scanning electron microscopy (SEM).

Results: Out of 115 S. aureus isolates, 63 (54.78%) showed biofilm formation by tube method. Biofilm forming bacteria were further categorized as high producers (n = 23, 20%) and moderate producers (n = 40, 34.78%). TM coordinated well with the coverslip assay for strong biofilm-producing strains in 19 (16.5%) isolates. By coverslip method, weak producers were difficult to differentiate from biofilm negative isolates. Screening on CRA showed biofilm formation only in four (3.47%) strains. Scanning electron micrographs showed the biofilm-forming strains of S. aureus arranged in a matrix on the propylene surface and correlated well with the TM.

Conclusion: Biofilm production is a marker of virulence for clinically relevant staphylococcal infections. It can be studied by various methods but screening on CRA is not recommended for investigation of biofilm formation in Staphylococcus aureus. Electron micrograph images correlate well with the biofilm production as observed by TM.

The prevalence of congenital and perinatal cytomegalovirus infections among newborns of seropositive mothers

Shahnaz AlKhawaja, Abdulrahman Ismaeel, Giuseppe Botta, Abiola Catherine Senok — Mon, 12 Sep 2011 02:37:50 -0700

Introduction: This study aimed to determine the prevalence of congenital and perinatal human cytomegalovirus (HCMV) infections among newborns in two major neonatal intensive care units (NICU) in Bahrain.

Methodology: One hundred newborns comprised of 84 preterm and 16 term babies admitted to the NICUs were enrolled in the study. During the first six weeks of life, urine and saliva was obtained from the babies weekly and serial breast milk samples were obtained from the mothers. Maternal serum HCMV IgG was measured. Virus isolation and detection was done by shell vial culture and nested PCR.

Results: Maternal HCMV IgG-seropositivity was 100%. Eight HCMV infections were detected comprising of three congenital and five perinatal infections. Congenital HCMV infection was found in preterm (2/84; 1.9%) and term (1/16; 6.3%) babies. HCMV DNA was detected in breast milk samples obtained during the first 10 days postpartum from all mothers whose babies had congenital HCMV. Forty-nine women provided breast milk samples between four and six weeks post-partum and HCMV DNA was detected in the breast milk of 11 women. Five (45.5%) of these eleven were mothers of babies with perinatal HCMV infection. There was no significant difference in the detection of HCMV using shell vial culture versus nested PCR method.

Conclusion: The findings indicate occurrence of congenital and perinatal HCMV transmission in this setting of high maternal seropositivity. The use of shell vial culture and PCR amplification for HCMV screening in the NICU for rapid detection of infection during the early postnatal period is recommended.

Healthcare-associated infections among pediatric oncology patients in Pakistan: risk factors and outcome

Naveed- ur-Rehman Siddiqui, Rabia Wali, Anwar- ul Haque, Zehra Fadoo — Tue, 13 Dec 2011 10:47:56 -0800

Introduction: Pediatric oncology patients are at increased risk of contracting healthcare-associated infections (HAIs), which are responsible for increased morbidity and mortality rates as well as treatment costs. This study aimed to identify the frequency of HAIs among pediatric oncology patients and their outcome.

Methodology: Pediatric oncology patients admitted between January 2009 and June 2010 in a pediatric ward at Aga Khan University Hospital, Karachi, Pakistan, who developed HAIs, were analyzed.

Results: A total of 90 HAIs were identified in 32 patients in 70 admissions. The HAI rate among pediatric oncology patients was 3.1/100 admission episodes. Bloodstream infections (63 episodes, 90.0%) were the most common, followed by urinary tract infection (two episodes, 2.9%). Gram-positive infections were seen in 54 (60%) patients, followed by Gram-negative infection in 34 (37.8%), and fungi in 2 (2.8%) cases. Coagulase negative staphylococci was the most common Gram-positive and Escherichia coli and Pseudomonas aeruginosa were most common Gram-negative infections. Mortality rate among pediatric oncology patients who developed HAIs was 12.5% (4/32). Total parental nutrition use and length of stay longer than 30 days were the identified risk factors associated with increased mortality among pediatric oncology patients who developed HAIs.

Conclusion: We report an HAI rate among pediatric oncology patients of 3.1/100 admission episodes with a mortality rate of 12.5% in Pakistan. Further studies should be done, especially in the developing world, to identify the risk factors associated with increased mortality among pediatric oncology patients so that adequate measures can be taken to reduce the mortality among these patients.

Knowledge, attitudes, perceptions, and practices regarding cutaneous larva migrans in deprived communities in Manaus, Brazil

Mon, 21 Nov 2011 09:28:56 -0800

Introduction: Hookworm-related cutaneous larva migrans (HrCLM) is a neglected parasitic skin disease commonly found in resource-poor communities in tropical countries. It is acquired via skin contact with faeces of cats and dogs, and causes intense pruritus and significant morbidity.

Methodology: We investigated knowledge, attitudes and practices in caregivers of patients with HrCLM by performing focus group discussions (FGDs) with 20 mothers of children with HrCLM in two endemic urban communities in Manaus, Brazil. Additionally, socio-demographic data of 70 actively detected HrCLM patients in both areas were obtained by using questionnaires.

Results: We found that mainly children who lived in large households and habitually walked barefoot were affected. Family income was low, housing was poor, and food shortage common. In the FGDs, mothers described HrCLM as a severely distressing condition with considerable impact on individual and family life.

Conclusion: Inadequate treatment practices and the identification of poverty-related obstacles for practical prevention of HrCLM by the mothers of affected children indicate that both health education and improvement of living conditions are required jointly.

Plasmodium falciparum and intestinal parasitic co-infections in HIV-infected patients in Benin City, Edo State, Nigeria

Frederick Olusegun Akinbo, Christopher Ehis Okaka, Richard Omoregie — Mon, 21 Nov 2011 09:38:42 -0800

Introduction: Human co-infection with Plasmodium falciparum and helminthes is ubiquitous throughout Africa. This study aimed to determine the co-infections of Plasmodium falciparum infection in HIV and intestinal parasitic infections, and their immunological distribution, in Benin City, Nigeria.

Methodology: A total of 2,000 stool specimens from HIV-positive patients and 500 controls (HIV-negative individuals) were examined for ova, cysts, or parasites using standard procedures. In addition, patients' blood samples were analyzed for CD4 counts by flow cytometry and examined for Plasmodium falciparum by microscopy.

Results: The prevalence of single parasitic infection among HIV patients was 18.1% in males and 16.9% among females with no significant difference (p = 0.536) while gender was a risk factor in multiple parasitic infections (male versus female: 4.2% and 1.8% OR = 2.384; 95% CI = 1.371, 4.147) (p = 0.0025). Increasing age was not associated with increased risk of both single and multiple parasitic infections (p = 0.083; p = 0.248). CD4 ⁺ T cell count less than 200 cells/µl was a risk factor for acquiring single and multiple parasitic infections among HIV patients (OR = 5.565; 95% CI = 4.136, 7.486; p = 0.0001; OR = 4.283; 95% CI = 2.424, 7.566; p = 0.0001). The most common co-infection observed was between Plasmodium falciparum and Ascaris lumbricoides 43% (10) among HIV patients.

Conclusion: This study provides evidence of co-infections between Plasmodium falciparum and intestinal parasites. Diagnosis of parasitic infections among HIV patients is advocated as this will enhance better management of HIV-infected patients.

Characterisation of novel strains of multiply antibiotic-resistant Salmonella recovered from poultry in Southern Senegal

Michel M Dione, Stanny Geerts, Martin Antonio — Wed, 30 Nov 2011 01:39:09 -0800

Introduction: Non-typhoidal Salmonella (NTS) contamination in poultry and poultry products is a major cause of food-borne disease in humans. This study presents the molecular epidemiology of NTS isolated from poultry in Senegal.

Methodology: A total of 261 NTS recovered from broiler farms, chicken carcasses and street vendors were characterized using random amplification of polymorphic DNA (RAPD) and multilocus sequence typing (MLST) techniques.

Results: We observed 20 distinct RAPD profiles corresponding to 18 different serotypes. Strains from each of these 20 groups were further analysed using MLST. Consequently, 12 new MLST alleles and 17 new sequence types were discovered. Three sequence types (S. Kentucky ST198, S. Agona ST13 and S. Istanbul ST33) have previously been described in Senegal and other countries, suggesting that these clones are geographically widely distributed and are circulating in a wide range of hosts. Nine clones showed multi-resistance to the most commonly used antibiotics in both humans and animals. However, a novel multi-resistant clone of S. Kentucky ST832 was found.

Conclusion: This study gives new insights into the genetic diversity of NTS in Senegal. Molecular tools remain essential to improve our understanding of the epidemiology of NTS by tracking the sources of infection and/or contamination.

Intra- and inter-laboratory evaluation of an improved multiplex-PCR method for detection and typing of Salmonella

Tue, 24 Jan 2012 08:57:13 -0800

Introduction: We developed and evaluated a multiplex-PCR method for rapid detection of the most common Salmonella serovars in both developed and developing countries. Additionally, the stability of the premixed reagents at high room temperature was studied.

Methodology: Fifty-two Salmonella strains belonging to the collections of the University of Sassari, Italy, and to the University of the Basque Country, Spain, and a collection of a hundred blinded strains, were used to evaluate the multiplex-PCR. Primers targeting genes STY1599 and fliC were selected, and the method was evaluated both intra and inter-laboratories.

Results: The inter-laboratory reproducibility was 95.92%, with a kappa index of 0.757 that indicates a substantial agreement and a high accuracy (80.81%). The sensitivity, specificity, accuracy and precision indexes for the Salmonella genus and S. Typhi targets were maximum, although the targets for Paratyphi A, Typhimurium and Enteritidis showed less accuracy. During a seven-week period, hot-start multiplex-PCR runs were performed with reagents mixed with wax to test their stability at 30ºC, and no significant variation in the patterns of amplification was observed.

Conclusions: An improved multiplex-PCR for rapid detection of the most common serovars of Salmonella operable in both developed and developing countries has been designed and tested intra and inter-laboratories. Following a careful optimization protocol will not only allow the confirmation of any suspicious colony by the amplification of the Salmonella genus target, but also the preliminary adscription to the prevalent serovars. Premixed reagents with wax facilitate the throughput and stability of reagents at high room temperatures.

Tigecycline and intravenous fosfomycin zone breakpoints equivalent to the EUCAST MIC criteria for Enterobacteriaceae

Fri, 17 Feb 2012 08:38:32 -0800

Introduction: Tigecycline and intravenous (i.v.) fosfomycin could be alternative therapeutic options for the treatment of carbapenemase-possessing Enterobacteriaceae bacterial infections. However, routine laboratories are forced to test these drugs using minimum inhibitory concentration (MIC) methods as zone breakpoints are not available for the disc diffusion technique.

Methodology: Clinical and Laboratory Standards Institute methods for agar dilution and disc diffusion were compared to determine tentative zone breakpoints that best correlate to tigecycline and i.v. fosfomycin MIC breakpoints defined by the European Committee on Antimicrobial Susceptibility Testing. A total of 195 Enterobacteriaceae with defined mechanisms of resistance were tested in duplicate assays. Half of the strains were characterized as carbapenemase producers (KPC-2, OXA-48, OXA-163, VIM-1, VIM-2, IMP-8, NDM-1).

Results: Corresponding zone diameters of susceptible ≥15mm, resistant ≤12mm and susceptible ≥17mm, resistant ≤15mm for the 50µg fosfomycin plus 50µg glucose-6-phosphate and 200µg fosfomycin plus 50µg glucose-6-phosphate discs, respectively, allowed categorization of the strains with an acceptable level of error (< 10% minor errors, < 1.5 % major errors, < 1% very major errors and categorical agreement > 90%). For the 15µg tigecycline disc, the best performance was achieved with the corresponding zone diameters of susceptible ≥ 21mm and resistant ≤ 16mm, which eliminated the very major and major errors but not the minor errors (34.4%).

Conclusions: Based on these results, tigecycline and fosfomycin can be included in the routine panel of antibiotics for susceptibility testing by disc diffusion to provide fast and reliable information for the selection of treatment alternatives, especially for strains with extreme resistance, as carbapenemase producers.

Detection of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae producing NDM-1 in Lebanon

Fri, 27 Jan 2012 10:29:19 -0800

Carbapenem resistance has been encountered globally with poor outcome of infected patients. NDM-1 (New Delhi metallo-beta-lactamase) gene containing organisms have emerged and are now spreading in all continents. This is the first report of Iraqi patients referred to Lebanon from whom carbapenem resistant Enterobacteriaceae were recovered. The genes involved in carbapenem resistance were bla-_OXA-48and the novel NDM-1. This report highlights the alarming introduction of such resistance among Enterobacteriaecae to this country.

Plasmid-mediated quinolone resistance determinant qnrB19 in non-typhoidal Salmonella enterica strains isolated in Venezuela

Fanny González, Lucia Pallecchi, Gian María Rossolini, María Araque — Thu, 19 Apr 2012 08:58:08 -0700

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