Evaluation of antibacterial activity of silver nanoparticles against multidrug-resistant gram negative bacilli clinical isolates from Zagazig University Hospitals

Background: The growing incidence of multidrug resistant (MDR) bacterial infections has become a public health crisis. This work aims to evaluate the in-vitro activity of silver nanoparticles (AgNPs), alone and in combination with the antimicrobials amikacin and ceftazidime, against MDR Gram-negative bacilli (GNB) isolated from clinical cases in Zagazig University Hospitals. Methods: In a cross sectional study, MDR GNB were isolated from different clinical specimens and were tested to determine the minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and bactericidal activity of AgNPs using broth microdilution method. The effect of combining subMIC levels of AgNPs (MIC/2 and MIC/4) with amikacin and ceftazidime, was also determined by broth microdilution. Results: A total of 63 MDR GNB was obtained during the study period (22 E. coli, 17 Klebsiella, 15 Pseudomonas aeruginosa and 9 Acinetobacter isolates). AgNPs demonstrated a bactericidal effect on all tested isolates with an MBC/MIC ratio of less than 4. When combined with amikacin, a synergistic effect was demonstrated on all tested E.coli and Klebsiella isolates at AgNPs MIC/2 and on 45.4%, 40% and 77.8% of E.coli, P.aeruginosa and Acinetobacter isolates, respectively at MIC/4. In combination with ceftazidime, AgNPs exhibited a synergistic effect on 100% of E. coli and 88.2% Klebsiella at both MIC/2 and MIC/4 and on 40% of P. aeruginosa isolates at AgNPs MIC/4. Conclusions: AgNPs exert a bactericidal activity on MDR GNB as well as a synergistic effect when combined with amikacin and ceftazidime suggesting them as a new weapon in the war against MDR GNB

Effect of physical stresses on survivability and post-exposure antibiotic susceptibility of coliforms in environmental waters and wastewaters

Background: Coliform bacteria are majorly introduced into water bodies (river and wastewater) as a result of faecal pollution, agricultural run-offs and several anthropogenic activities. Despite the effectiveness of water treatment methods, pathogens still persist in water; hence the relevance of assessing the ability of these pathogens to survive the lethal actions of physical stresses and the possible impact on antibiotic susceptibility pattern of the organisms. Methodology: The survivability of Escherichia coli strains (NCM3722, FAP1 and ST2747), Enterobacter cloacae GGT036 and Shigella sonnei 53G was assessed in environmental and waste waters for 21 days. The effect of three treatment regimens (UV radiation, solar radiation and boiling) on the survival of the coliforms was evaluated. Also, the antibiogram of the isolates post­UV exposure was assayed. Results: Although there was significant reduction (≥ 3-log) in the population of the bacteria overtime, all the coliforms survived in the waters for 21 days. The effect of UV radiation was significant on all organisms (> 3 log reductions). Solar radiation for 60 minutes had significantly lesser effect than boiling for 15 minutes. Surviving cells of all isolates demonstrated multiple drug-resistance post exposure to UV radiation. Conclusion: This study revealed the ability of coliforms to persist in waters after treatment and proves that UV radiation may not be effective in attenuation of antibiotic resistance

Etiology and pathogenicity of bacterial isolates: a cross sectional study among diarrheal children below five years in central regions of Kenya

Introduction: bacterial agents are among pathogens implicated to cause diarrhea in children resulting to huge mortality and morbidities. Bacterial etiologies causing diarrhea in children below five years are rarely investigated in Central Kenya, which would otherwise guide prescription and target health education.Methods: a cross-sectional study approach was applied on 163 randomly selected stool samples from children below five years who presented with diarrhea in Murang`a and Muriranja`s hospitals. The objective was to determine the bacterial agents of diarrhea. Enteric bacterial pathogens were cultured using appropriate media and identified. Statistical analyses were performed using STATA v.13. Chi-square or Fisher exact-test were used to check for evidence of relationship whenever applicable.Results: there were nearly equal distributions in gender 86 (52.8%) female vs. 77 (47.2%) male, majority (35.6%) aged between 0-12 months. Bacterial isolates were highly diverse in female than the male, children aged 49-60 months and least among those aged 0-12 months. A total of 188 bacterial isolates belonging to 11 genera were recovered. The predominant bacteria was nonpathogenic Escherichia coli 85 (45.2%), while 13 (6.9%) Escherichia coli were positive for virulence genes, including 8 (4.3%) positive for LT and STp Shiga-like or Enterotoxigenic Escherichia coli, 3 (1.6%) positive for eae and bfpA Enteropathogenic Escherichia coli and 2 (1.1%) positive for Enteroaggregative Escherichia coli gene. Others included: Salmonella 21 (11.2%), Pseudomonas 14 (7.4%), Shigella 14 (7.4%), Klebsiella 12 (6.4%), Aeromonas 8 (4.3%), Enterobacter 7 (3.7%), Proteus 8 (4.3%), Citrobactor 3 (1.6%), Yersinia 2 (1.1%) and Vibrio 1 (0.5%).Conclusion: salmonella was the major bacterial isolate and majority of the bacteria were statistically significant cause of diarrhea (p=0.001)

Antibiotic sensitivity patterns of enterobacteriaceae isolated at King Faisal Hospital; Kigali - a three years study

Introduction: A great concern exists about the emergence of antibiotic resistant organisms. The goal of this study is to delineate antibiotic sensitivity patterns at King Faisal Hospital. Methods: A three years study; from Jan 2009 to Dec 2011 was conducted in the Microbiology unit; department of Laboratory; King Faisal hospital; Rwanda. All the specimens and antibiotic sensitivity were processed according to the standard guidelines. Microorganisms and their sensitivity data were reviewed and compiled by using hospital information system. Results: Over the 3-year period; several Enterobacteriaceae pathogens declined in susceptibility to various antimicrobial agents. A total of 2153 Enterobacteriaceae were isolated. Most common isolate was Escherichia coli check for this species in other resources (1413) followed by Klebsiella check for this species in other resources species (550); Enterobacter check for this species in other resources species (110); Proteus check for this species in other resources species (165); Citrobacter check for this species in other resources Species (79); Shigella check for this species in other resources species (110) and other species. Most notable were the decreased sensitivities to cefuroxime: E. coli (84 to 72); Klebsiella (78 to 33); Enterobacter (50 to 41) Proteus(67 to 59) and Shigella to ciprofloxacin (100 to 96). And also decreased sensitivities to Imipenem: E. coli (100 to 98) and Klebsiella species (100 to 94). Conclusion: These decreased antibiotic sensitivities reflect increased bacterial selection pressure as a result of widespread antibiotic use. A combined approach involving infection-control specialists; infectious disease physicians; and hospital administrators is necessary to address this increasingly difficult problem

Epidemiological studies on proteeae isolates from clinical specimens in the Laquintinie Hospital in Douala, Cameroon

The tribe Proteeae is a group of bacteria within the family Enterobacteriaceae and is responsible for most cases of nosocomial infections in hospital settings. The objective of this study was to determine the prevalence of members of Proteeae from clinical specimens in Laquintinie hospital in Douala. Specimens were collected from patients and screened for Proteeae using standard microbiological and biochemical methods (API 20 Enterobacteriaceae gallery). Of the 3414 clinical specimens made of 2712 urine; 264 blood; 243 CSF and 195 wounds and burns; 1136 (33.3) yielded a positive bacterial growth; of which 230 (20.2) were Gram positive and 906 (79.7) were Gram negative. 164 (14.4) isolates were identified as members of Proteeae of which 110 (67.1) were from urine; 37( 22.6) from wounds and burns; 10(6.1) from blood and 7( 4.3) from CSF. Speciation of the Proteeae isolates showed that 111 (67.7) were Proteus mirabilis; 21(12.8) Proteus vulgaris; 11 (6.7) Providencia alcalifaciens; 6 (3.6) Providencia stuartii; 4 (2.4) Morganella morganii and 5 (3.0) Proteus penneri and Providencia rettgeri. There was a significant difference between the type of clinical specimens and the age of patients (X2 = 52.623 p0.05). Most Proteeae isolates where susceptible to imipemen; ceftazidine; chloramphenicol; gentamicin; nalidixic acid; ofloxacin and amikacin. These findings have significant clinical and epidemiological implications

Microbiological Water Quality Monitoring in a Resource-Limited Urban Area: a Study in Cameroon; Africa

In resource-limited developing nations; such as Cameroon; the expense of modern water-quality monitoring techniques is prohibitive to frequent water testing; as is done in the developed world. Inexpensive; shelf-stable 3MT PetrifilmT Escherichia coli/Coliform Count Plates potentially can provide significant opportunity for routine water-quality monitoring in the absence of infrastructure for state-of-the-art testing. We used shelf-stable E. coli/coliform culture plates to assess the water quality at twenty sampling sites in Kumbo; Cameroon. Culture results from treated and untreated sources were compared to modern bacterial DNA pyrosequencing methods using established bioinformatics and statistical tools. Petrifilms were reproducible between replicates and sampling dates. Additionally; cultivation on Petrifilms suggests that treatment by the Kumbo Water Authority (KWA) greatly improves water quality as compared with untreated river and rainwater. The majority of sequences detected were representative of common water and soil microbes; with a minority of sequences (40) identified as belonging to genera common in fecal matter and/or causes of human disease. Water sources had variable DNA sequence counts that correlated significantly with the culture count data and may therefore be a proxy for bacterial load. Although the KWA does not meet Western standards for water quality (less than one coliform per 100 mL); KWA piped water is safer than locally available alternative water sources such as river and rainwater. The culture-based technology described is easily transferrable to resource-limited areas and provides local water authorities with valuable microbiological safety information with potential to protect public health in developing nations

Epidemiologie moleculaire des betalactamases a spectre elargi produites par des Enterobacteriaceae d'origine fecale isolees chez les habitants de residences estudiantines a l'Universite de Kinshasa (RDC)

Objectif : Determiner l'epidemiologie moleculaire des Enterobacteriaceae productrices des betalactamases a spectre elargi (E-BLSE) chez les habitants de residence estudiantines a l'Universite de Kinshasa. Methodes : Des echantillons de selles preleves chez 516 etudiants ont ete examines pendant la periode du 15 novembre 2005 au 30 avril 2006. A l'aide de la galerie API 20E; nous avons pu identifier les differentes souches d'enterobacteries. La production de BLSE a ete recherchee par le test de synergie en double disque; puis confirmee et caracterisee par la focalisation isoelectrique; la PCR et le sequencage des genes de resistance. Un questionnaire a permis de recueillir les informations sur la demographie et les antecedents d'antibiotherapie des sujets inclus dans l'etude. Resultats : La frequence des E- BLSE etait de 17;8chez ces etudiants. Aucune correlation n'a ete notee entre un antecedent d'antibiotherapie et la presence d'E-BLSE. Parmi les E-BLSE isolees; Escherichia coli etait l'espece majoritaire (65); suivi de Klebsiella pneumoniae (26) etn d'Enterobacter cloaceae (5;4). CTX-M-15 etait l'ESBL predominante (29); suivie de CTX-M-28 (19;6); TEM- 68 (16;8); TEM-104 (9;3); CTX-M-3 (9;3); CTX-M-n 22 (4;7) ; SHV-12 (4;7); TEM-168 (1;9); TEM-144 (0;9); SHV-5 (0;9); SHV-2 (0;9); CTX-M-34 (0;9); CTX-M-62 (0;9). CTX-M-15 etait presente dans toutes les souches d'Escherichia coli isolees. Conclusion : Cette etude est; a notre connaissance; la premiere sur l'epidemiologie et la caracterisation des BLSE en RDC. La frequence des E-BLSE dans les residences estudiantines de l'Universite de Kinshasa; ainsi que la presence d'une grande variete de BLSE; justifieraient l'extension de ce type d'enquete dans la communaute et en milieu hospitalier; afin d'evaluer l'ampleur reelle du probleme et de definir des strategies adequates de pharmacovigilance et de lutte contre les bacteries multiresistantes aux antibiotiques

Antimicrobial Susceptibility Patterns of Selected Invasive Pathogens from Public Sector Hospitals in South Africa; 2007

Retrospective antibiotic surveillance data of selected invasive pathogens isolated from blood and cerebrospinal fluid at public sector hospitals in South Africa in 2007 are presented. Antimicrobial susceptibilities were determined according to the 2007 Clinical and Laboratory Standards Institute criteria. Klebsiella pneumoniae remains a highly resistant pathogen; with approximately half of all strains producing extended-spectrum beta-lactamases. All laboratories reported considerable resistance among Acinetobacter spp. Approximately 50-60of Staphylococcus aureus isolates from blood were resistant to cloxacillin. Among Streptococcus pneumoniae isolates from blood and cerebrospinal intermediate resistance to penicillin. Resistance to ceftriaxone in S. pneumoniae was rare

Increasing Prevalence of Antimicrobial Resistance among Enterobacteriaceae Uropathogens in Bangui; Central African Republic

Background: Because of the previous high prevalence of resistance to usual antibiotics among uropathogens in Bangui; Central African Republic (CAR); a survey focused on Enterobacteriaceae; the most prevalent group responsible for urinary tract infections (UTIs); was conducted. The aim was to help health authorities revise antibiotic policies.Methodology: We performed a retrospective analysis of all cases of confirmed UTIs due to Enterobacteriaceae in outpatients attending the Institut Pasteur de Bangui (IPB); CAR; between 2004 and 2006. Results: During the study period; 560 (10.9of urine submissions) UTIs were confirmed and 443 Enterobacteriaceae strains were isolated; representing 79of the causative agents for UTIs. Among these 560 strains; E. coli was the most common; representing 64of the isolates; followed by K. pneumoniae (10) and other Enterobacteriaceae (5). Extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae significantly increased from five (3.7) to thirty-three (19.3) between 2004 and 2006. A significantly increased resistance rate to nalidixic acid; ciprofloxacin and gentamicin was observed in ESBL-nonproducing Enterobacteriaceae over the study period. Conclusions: Empiric treatment for UTIs in Bangui should be reconsidered and prudent use of antibiotics; particularly ciprofloxacin; is highly recommended. The recent spread of ESBL-producing Enterobacteriaceae in central African outpatients is striking and underlines the need for further studies

Dissolved Organic Carbon (DOC) and Coliform Bacteria in Underground Water in Areas around Nairobi

Most people in areas surrounding Nairobi use untreated underground waters for their domestic chores. A study was carried out during the wet season (April-June) and the dry season (September-November) of the year 1994 to find out if these untreated underground waters contain dissolved organic carbon (DOC) and coliform bracteria. Out of the 40 sites sampled during both the wet and dry seasons; 11 contained colifrorm bacteria during the wet season; while only 2 contained the microbes during the dry season. The microbes were detected only in the wells. DOC was detected in 37 sites during the wet season and in 31 sites during the dry season within a range of 2.0-30.8 mg L-1. DOC which mainly consists of humic and fulvic acids was quantified by measuring their absorbance at 360nm by UV-VIS spectrophotometry. The presence of coliform bacteria was detected by use of microbiological techniques

Epidemiology of Antimicrobial Resistance in pathogens Isolated in Mulago Hospital in 1998 and 2000

This study analysed the antimicrobial resistance distribution of Staphylococcus; Enterobacteria; Haemophillus and Pseudomonas isolated from the common service departments in Mulago Hospital; over periods of 1998 and 2000. The Standard Errors (se) of two proportions (resistance) and 95Confidence Interval (CI) for the difference between two proportions were used as statistical tests for determining whether there were changes being experienced over the study period. The analysed agents such as Methicillin; Etythromycine and Ceftazidime did not change in resistance point prevalence mechanisms that do not modify or attack them. While Augumentin; Sodium Cefuroxime; Chloramphenicol; Ciprofoxacin; Gentamicin; Tetracycline and Nitrofurantoin showed icnreased resistance prevalence (P0.05 possibly because of being overused or modified by many resistance mechanisms; high rates of resistance were seen in Enterobacteria (67); Staphylococcus (62) and haemophilus (50). Antipseudomonal agents did not show change in resistance prevalence (P0.05). Departmental/ward distribution of resistant isolates did not also change; except in Emergency and Outpatient departments since bacterial ecology tends to keep constant unless contronted by high level of infection control practice