Antimicrobial resistance in Escherichia coli strains from urinary tract infections

An ST131 clade and a phylogroup A clade bearing an O101-like O-antigen cluster predominate among bloodstream Escherichia coli isolates from South-West Nigeria hospitals

Escherichia coli bloodstream infections are typically attributed to a limited number of lineages that carry virulence factors associated with invasiveness. In Nigeria, the identity of circulating clones is largely unknown and surveillance of their antimicrobial resistance has been limited. We verified and whole-genome sequenced 68 2016-2018 bloodstream E. coli isolates from three sentinel sites in South-Western Nigeria and susceptibility tested 67 of them. Resistance to antimicrobials commonly used in Nigeria was high, with 67 (100 %), 62 (92.5 %), 53 (79.1 %) and 37 (55.2 %) showing resistance to trimethoprim, ampicillin, ciprofloxacin and aminoglycosides, respectively. Thirty-five (51 %) isolates carried extended-spectrum β-lactamase genes and 32 (91 %) of these were multidrug resistant. All the isolates were susceptible to carbapenems and colistin. The strain set included globally disseminated high-risk clones from sequence type (ST)12 (2), ST131 (12) and ST648 (4). Twenty-three (33.8 %) of the isolates clustered within two clades. The first of these consisted of ST131 strains, comprising O16:H5 and O25:H4 sub-lineages. The second was an ST10-ST167 complex clade comprising strains carrying O-antigen and capsular genes of likely Klebsiella origin, identical to those of avian pathogenic E. coli Sanji, and serotyped in silico as O89, O101 or ONovel32, depending on the tool used. Four temporally associated ST90 strains from one sentinel were closely related enough to suggest that at least some of them represented a retrospectively detected outbreak cluster. Our data implicate a broad repertoire of E. coli isolates associated with bloodstream infections in South-West Nigeria. Continued genomic surveillance is valuable for tracking clones of importance and for outbreak identification.

Molecular epidemiology of antibiotic-resistant genes and potent inhibitors against TEM, CTX-M-14, CTX-M-15, and SHV-1 proteins of Escherichia coli in district Peshawar, Pakistan

The Extended Spectrum Beta-Lactamases (ESBLs) producing bacteria is an issue of concern for clinicians resulting in minimize the treatment options. To overcome resistance mechanisms, novel inhibitors with good Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties must inhibit the ESBLs resistant genes. The current study aimed to identify the antibiotic resistance genes of ESBLs producing E. coli and a single inhibitor was designed to inhibit all the resistant proteins. The results showed that 42.9% ESBL producers had CTX-M (69.9%), TEM (63.4%), SHV (34.5%) and CTX-M-14 (17.5%) genes. The ESBLs producing isolates were resistant to cephalosporins, quinolones, and sulfonamide with Minimum Inhibitory Concentration (MICs) ranging from 64 to >256 μg/ml. To design multi inhibitory ligands, RECAP synthesis was used for the de-novo discovery of 1000 inhibitors database. Protein crystal structures were retrieved from Protein Data Base (PDB). Lipinski's rules of five were applied to the novel inhibitors database to improve the ADMET properties. The novel inhibitors database was selected for docking simulations. Placement of the ligand was used by the London dG algorithm implemented in Molecular Operating Environment (MOE), while GBVI/WSA dG algorithm was used for final refinement. Based on docking score, visual inspection of ligands interaction with key residues, binding affinity, and binding energy of ligands with proteins, ten compounds were selected for ESBLs proteins with best ADMET properties, binding energy, and binding affinity the reported ones. These hits compounds have unique scaffolds and are predicted to be a starting point for developing potent inhibitors against antibiotic-resistant proteins.

Molecular detection of Extended-Spectrum β-lactamases (ESBLs) and biofilm formation in uropathogen Klebsiella pneumoniae in Iran

Background: Uropathogenic Klebsiella pneumoniae is one of the well-kown uropathogens that have the main rule in biofilm formation. Increased prevalence of ESBL enzyme is one of the therapeutic problems. However, the aims of this study were to characterize the ability of biofilm formation and ESBL-producing isolates produced by urinary tract infection’s K. pneumoniae to identify the prevalence of this type of infection in the studied area.

Methods: Between the 500 nonrepetitive clinical isolates, 128 isolates were detected as K. pneumoniae. Biofilm production of these isolates was showed by Merrit and Christensen method. The standard Kirby-Bauer disk diffusion method was used for antimicrobial susceptibility testing. The phenotype ESBL was confirmed by double disc synergy test (DDST). Genotypic identification of ESBLs did by molecular detection. The statistical analysis was done using software IBM SPSS Statistics (SPSS Inc) and chi-square and Fisher exact tests.

Results: The result of microtiter plate was observed and it was found that 86 (67.2%) isolates had weak biofilm, 24 (18.8%) moderate biofilm, and 18 (14.1%) strong biofilm. Also, 57 (44.5%) out of 128 isolates were diagnosed as MDR. The highest frequency of resistance was identified for cefotaxime 60 (46.9%) and tetracycline 60 (46.9%), and the lowest rate was for amikacin 16 (12.5%). The results of DDST showed 55 of 128 (43%) produced ESBL enzymes. PCR detection in ESBL-producing isolates showed contained bla_TEM 33 of 55(63.1%), and bla_VEB 13 of 55 (23% ). Also, 1 of 55 (2%) had both bla_TEM and bla_VEB. Also, 5 of 13 (38.4%) isolates that had the bla_VEB gene were also MDR and had weak biofilm (8/13; 61.5%), intermediate biofilm (3/13; 23%), and strong biofilm (2/13; 15.4%).

Conclusion: To decrease treatment complications and mortality rate of drug-resistant bacterial infections, rapid detection of β-lactamases genes and evaluation of these properties and infection management programs can help to prevent the transmission of drug resistant-strains.

Etiological Agents of Urinary Tract Infection and 7 Years Trend of Antibiotic Resistance of Bacterial Uropathogens in Sudan

Introduction:

Bacterial infections of the urinary tract represent a major cause of outpatient visits as well as hospital-acquired infections. As the prevalence of multidrug-resistant uropathogens is increasing, updated knowledge of the commonest bacterial causes and their susceptibility patterns is crucial for the proper selection and use of antimicrobial drugs and the development of effective local prescribing guidelines.

Methods:

Handling of urine samples, identification of organisms and antimicrobial susceptibility testing were made according to guidelines in Monica Cheesbrough 2000, 2006. The prevalence of resistance of the pathogens against each antibiotic was calculated as the proportion of resistant isolates over the entire tested isolates. Data were analyzed using Epi info; the chi-square test and Fisher exact test were used to assess the statistical significance of results.

Results:

In this study, 774 samples were cultured from patients with suspected urinary tract infection (UTI), 705 (91%) urinary isolates showed significant growth (>105 CFU /L) while the other 69 samples showed no significant growth. 431 (61%) of the patients were female, while the other 274 (39%) were males. 13 types of pathogens were identified in 705 urinary isolates. E.Coli was the main bacterial uropathogen identified. Microbiological susceptibility of a total of 28 antibiotics was tested; for each urinary isolate, different sets of these antibiotics were used. 601(96%) of the bacteria were resistant to at least one antibiotic. 17 antibiotics were found to have a bacterial resistance rate of more than 50%, including all B lactams (except cefuroxime), Nalidixic acid, Ciprofloxacin, Norfloxacin, Clindamycin, Co-Trimoxazole and Tetracyclines(Tetracycline and Doxycycline). Other antibiotics were found to have resistance rates of less than 50%. Amikacin & Imipenem had the highest susceptibility rates. Throughout the 7 years, resistance to most of the antibiotics showed an incremental pattern.

Conclusion:

Current empirical antibiotic therapy for UTI should be modified, and new guidelines should be established based on local resistance rates. This study comes up with precious regional data for evidence-based empirical antibiotic treatment, but a national sentinel surveillance system and regional antibiograms should be established to track the bacterial susceptibility profiles in Sudan.

α-Hemolysin of uropathogenic E. coli regulates NLRP3 inflammasome activation and mitochondrial dysfunction in THP-1 macrophages

Hemolysin expressing UPEC strains have been associated with severe advanced kidney pathologies, such as cystitis and pyelonephritis, which are associated with an inflammatory response. Macrophages play an important role in regulating an inflammatory response during a urinary tract infection. We have studied the role of purified recombinant α-hemolysin in inducing inflammatory responses and cell death in macrophages. Acylation at lysine residues through HlyC is known to activate proHlyA into a fully functional pore-forming toxin, HlyA. It was observed that active α-hemolysin (HlyA) induced cleavage of caspase-1 leading to the maturation of IL-1β, while inactive α-hemolysin (proHlyA) failed to do so in THP-1 derived macrophages. HlyA also promotes deubiquitination, oligomerization, and activation of the NLRP3 inflammasome, which was found to be dependent on potassium efflux. We have also observed the co-localization of NLRP3 within mitochondria during HlyA stimulations. Moreover, blocking of potassium efflux improved the mitochondrial health in addition to a decreased inflammatory response. Our study demonstrates that HlyA stimulation caused perturbance in potassium homeostasis, which led to the mitochondrial dysfunction followed by an acute inflammatory response, resulting in cell death. However, the repletion of intracellular potassium stores could avoid HlyA induced macrophage cell death. The findings of this study will help to understand the mechanism of α-hemolysin induced inflammatory response and cell death.

Phenotypic and molecular characterization of antimicrobial resistant Escherichia coli from urinary tract infections in Port-Harcourt, Nigeria

Introduction

Multidrug resistance among Escherichia coli causing Urinary Tract Infections (UTIs) is a major public health problem, threatening the effective treatment of UTIs. This study investigated the phenotypic and molecular characteristics of E. coli associated with UTIs in Port-Harcourt, Nigeria.

Methods

Twenty-five non-duplicate isolates of E. coli from UTIs patients at the University of Port-Harcourt Teaching Hospital, Nigeria were identified using Matrix-Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry. The antimicrobial susceptibility patterns were determined using Kirby-Bauer disc diffusion technique. Phenotypic expression of Extended Spectrum Beta Lactamases (ESBLs) and AmpC beta-lactamase were determined using standard laboratory methods and polymerase chain reaction (PCR) was used to detect ESBLs, AmpC, Quinolones and Aminoglycosides resistance genes.

Results

The isolates exhibited high rates of resistance to co-trimoxazole (76%), nalidixic acid (68%), ciprofloxacin (60%), gentamicin (44%) and low resistance to cefotaxime (20%) but were fully susceptible to cefoperazone/sulbactam, amikacin, nitrofurantoin, colistin and carbapenems. Phenotypic expression of ESBLs was recorded in 6(24%) isolates while genotypic detection revealed the highest prevalence of blaTEM 22(88%), followed by blaCTX-M-15 16(64%), blaSHV 7(28%) and blaOXA-1 6(24%) while AmpC (blaCMY-2) gene was detected in 8(32%) isolates. Amongst the quinolone resistant isolates, qnr variants (qnrB, qnrD and qnrS) and aac(6')-Ib genes were detected in 7(28%) and 3(12%) isolates respectively while all gentamicin resistant isolates possessed the aacC2 gene. The co-expression of blaCTX-M-15 with quinolones and aminoglycoside genes were 20% and 40% respectively. The prevalence of multiple drug resistance was 52%.

Conclusion

A high proportion of the studied E. coli isolates co-expressed ESBLs, quinolones and aminoglycosides resistance genes which call for prompt antibiotic stewardship and preventive strategies to limit the spread of these genes.

Regulation of hemolysin in uropathogenic Escherichia coli fine-tunes killing of human macrophages

Uropathogenic E. coli (UPEC) causes the majority of urinary tract infections (UTIs), which are a major global public health concern. UPEC uses numerous mechanisms to subvert the innate immune system, including targeting macrophage functions. We recently showed that some UPEC strains rapidly kill human macrophages via an NLRP3-independent pathway, and also trigger NLRP3-dependent IL-1β processing. In this study, we used random transposon mutagenesis in the reference strain CFT073 to identify UPEC genes that mediate human macrophage cell death. Our approach revealed that the hemolysin A (HlyA) toxin is essential for triggering both cell death and NLRP3 inflammasome-mediated IL-1β release in human macrophages. Random transposon mutagenesis also identified the cof gene, which encodes a poorly characterized phosphatase, as a novel hemolysin regulator; a CFT073 mutant deleted for the cof gene secreted significantly reduced levels of HlyA, had diminished hemolytic activity, and was impaired in its capacity to trigger human macrophage cell death and IL-1β release. Together, our findings reveal that Cof fine-tunes production of hemolysin, an important determinant of both UPEC-mediated inflammasome activation and human macrophage cell death.

Prevalence and Antimicrobial Susceptibility of Bacterial Uropathogens Isolated from Pediatric Patients at Yekatit 12 Hospital Medical College, Addis Ababa, Ethiopia

BACKGROUND

Urinary tract infection (UTI) is considered as the most common bacterial infection seen among the pediatric patients.

OBJECTIVE

This study was carried out in order to determine the prevalence of urinary tract infection in pediatric patients, identify bacterial uropathogens responsible for the infection, and study the antibiotic sensitivity patterns of bacterial isolates.

MATERIALS AND METHODS

A cross-sectional study designed and conducted from January to April 2014. Clean-voided midstream urine specimens were obtained from 384 pediatric patients less than or equal to 15 years in sterile universal bottles. Urine collected from each patient was inoculated onto CLED and blood agar plates using a calibrated inoculating loop with a capacity of 0.001 ml. Inoculated plates were incubated for 24-48 hours at 37°C at inverted position aerobically. Bacterial isolates were indentified and characterized by Gram stain and by using an array of standard routine biochemical tests. The antimicrobial susceptibility test was carried out by using the Kirby-Bauer disc diffusion method. Frequency distribution tables were used to describe the findings. Logistical regression was also used to estimate crude odds ratio (COR) with 95% confidence interval (CI) of positive responses to the different variables, and P values less than 0.05 were taken as statistically significant.

RESULT

In this study, a total of 384 patients (199 males and 185 females) aged less than or equal to 15 years from whom urine samples were collected were enrolled. Of these patients, 61 (15.9%) had significant bacteriuria. Of the 185 females, 36 (19.5%) came up with positive cultures, while 25 (12.6%) of the 199 males had significant bacteriuria, and the largest number of study subjects were below the age of 3 years, and the largest positive culture was obtained from this age group, accounting for 35 (57.4%.) out of 61 positive cultures. Bacterial species belonging to six genera were isolated and identified from 61 positive cultures, and the genera were Escherichia, Klebsiella, Staphylococcus, Proteus, Acinetobacter, and Enterococcus. E. coli was isolated in 28 cases (49.5 %), followed by Klebsiella spp. in 17 cases (27.9%), Staphylococcus spp. in 5 patients (8.2%.) (S. aureus in one and coagulase-negative staphylococci in 4 cases), Enterococcus in 7 cases (11.5%), Proteus spp. in 3 cases (4.9%), and Acinetobacter in one case (1.6%). Of the bacterial isolates, E. coli was found out to be the most common pathogen followed by Klebsiella spp. Furthermore, E. coli and Klebsiella spp. were the most common pathogens in female patients accounting for 71.4% and 64.7%, respectively. Regarding susceptibility tests, E. coli and Klebsiella spp. were not 100% susceptible to any of the 11 antibiotics tested. Acinetobacter spp. had 100% resistance to three antibiotics: gentamicin (GN), trimethoprim-sulfamethoxazole (SXM), and augmentin (AMP). But they were 100% susceptible to ciprofloxacin (CIP), cefuroxime (CXM), norfloxacin (NOR), and ceftazidime (CAZ). On the contrary, Proteus spp. was 100% sensitive to all drugs except to nitrofurantoin. Species of Enterococcus had resistance of 71.4% to chloramphenicol (C) and 85.7% to both SXM and erythromycin. S. aureus was 100% susceptible to almost all drugs, while coagulase-negative staphylococci were not as susceptible as S. aureus. Multidrug resistance to two or more drugs was observed in 73.7% of the bacterial isolates.

CONCLUSION

This study determined the prevalence of urinary tract infection in pediatric patients and highlighted the major bacterial uropathogens involved in UTI for the first time in the country. Furthermore, bacterial pathogen species and their frequency was consistent with the usually reported pattern, with E. coli being the most common organism isolated in cases of urinary tract infections followed by Klebsiella spp. Most of the bacterial isolates were multidrug resistant, and it is therefore suggested that appropriate antimicrobials should be administered to reduce the risk of multidrug resistant organisms developing and avert ineffectiveness of antibiotics. This condition indicates that antibiotic selection should be based on knowledge of the local prevalence of bacterial organisms and antibiotic sensitivities rather than empirical treatment. The present study indicated that ciprofloxacin (CIP), ceftazidime (CAZ), cefotaxime (CTX), cefuroxime (CXM), clindamycin (DA), and ceftriaxone (CRO) were the best antibiotics for the treatment of Gram-negative and Gram-positive bacterial uropathogens, respectively, in the study area relatively.

Antimicrobial resistance in West Africa: a systematic review and meta-analysis

Growing data suggest that antimicrobial-resistant bacterial infections are common in low- and middle-income countries. This review summarises the microbiology of key bacterial syndromes encountered in West Africa and estimates the prevalence of antimicrobial resistance (AMR) that could compromise first-line empirical treatment. We systematically searched for studies reporting on the epidemiology of bacterial infection and prevalence of AMR in West Africa within key clinical syndromes. Within each syndrome, the pooled proportion and 95% confidence interval were calculated for each pathogen-antibiotic pair using random-effects models. Among 281 full-text articles reviewed, 120 met the eligibility criteria. The majority of studies originated from Nigeria (70; 58.3%), Ghana (15; 12.5%) and Senegal (15; 12.5%). Overall, 43 studies (35.8%) focused on urinary tract infections (UTI), 38 (31.7%) on bloodstream infections (BSI), 27 (22.5%) on meningitis, 7 (5.8%) on diarrhoea and 5 (4.2%) on pneumonia. Children comprised the majority of subjects. Studies of UTI reported moderate to high rates of AMR to commonly used antibiotics including evidence of the emergence of cephalosporin resistance. We found moderate rates of AMR among common bloodstream pathogens to typical first-line antibiotics including ampicillin, cotrimoxazole, gentamicin and amoxicillin/clavulanate. Among S. pneumoniae strains isolated in patients with meningitis, levels of penicillin resistance were low to moderate with no significant resistance noted to ceftriaxone or cefotaxime. AMR was common in this region, particularly in hospitalized patients with BSI and both outpatient and hospitalized patients with UTI. This raises concern given the limited diagnostic capability and second-line treatment options in the public sector in West Africa.

Methicillin-resistant Staphylococcus aureus as a uropathogen in an Irish setting

Urinary tract infections are one of the most common infectious diseases diagnosed in the community and in the hospital setting. Their treatment is complicated by drug-resistant pathogens and the colonization by microbes of indwelling urinary catheters. This study assessed the occurrence and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) uropathogens isolated for 5 consecutive years at University Hospital Waterford between 2010 and 2014. We created 4 clinically relevant subdivisions, based on urine source: hospital inpatients, patients from the Emergency Department, patients referred from their General Practitioner, and Nursing Home patients. We performed a retrospective review from the hospital's electronic microbiological system and calculated resistance rates for each of the standard antimicrobial agents. During the 5-year study period, we studied 151 urine isolates obtained from 128 patients who had an MRSA cultured in their urine sample. There was 100% resistance of all MRSA isolates to Flucloxacillin and Coamoxiclav. Ninety-eight percent of isolates were resistant to Ciprofloxacin. The resistance rate for Trimethoprim was 7.4% and there was only 2.7% resistance for Nitrofurantoin. For a clinical subset of patients, we also demonstrated 100% sensitivity for samples tested against Teicoplanin and Vancomycin. Urinary MRSA is an infrequently studied phenomenon, but with the rising trend of hospital superbugs nationally, its management is of critical importance. Suitable agents to address this within our population include Nitrofurantoin in the well patient requiring urinary MRSA eradication or Vancomycin/Teicoplanin in the unwell patient requiring intravenous therapy. In all groups, fluoroquinolones should be avoided due to significant resistance rates.

Spread of TEM, VIM, SHV, and CTX-M β-Lactamases in Imipenem-Resistant Gram-Negative Bacilli Isolated from Egyptian Hospitals

Carbapenem-resistant Gram-negative bacilli resulting from β-lactamases have been reported to be an important cause of nosocomial infections and are a critical therapeutic problem worldwide. This study aimed to describe the prevalence of imipenem-resistant Gram-negative bacilli isolates and detection of bla_VIM, bla_TEM, bla_SHV, bla_CTX-M-1, and bla_CTX-M-9 genes in these clinical isolates in Egyptian hospitals. The isolates were collected from various clinical samples, identified by conventional methods and confirmed by API 20E. Antibiotic susceptibility testing was determined by Kirby-Bauer technique and interpreted according to CLSI. Production of bla_VIM, bla_TEM, bla_SHV, and bla_CTX-M genes was done by polymerase chain reaction (PCR). Direct sequencing from PCR products was subsequently carried out to identify and confirm these β-lactamases genes. Out of 65 isolates, (46.1%) Escherichia coli, (26.2%) Klebsiella pneumoniae, and (10.7%) Pseudomonas aeruginosa were identified as the commonest Gram-negative bacilli. 33(50.8%) were imipenem-resistant isolates. 22 isolates (66.7%) carried bla_VIM, 24(72.7%) had bla_TEM, and 5(15%) showed bla_SHV, while 12(36%), 6(18.2%), and 0(0.00%) harbored bla_CTX-M-1, bla_CTX-M-9, and bla_CTX-M-8/25, respectively. There is a high occurrence of β-lactamase genes in clinical isolates and sequence analysis of amplified genes showed differences between multiple SNPs (single nucleotide polymorphism) sites in the same gene among local isolates in relation to published sequences.

Origin and Dissemination of Antimicrobial Resistance among Uropathogenic Escherichia coli

Antimicrobial agents of various types have important bearing on the outcomes of microbial infections. These agents may be bacteriostatic or –cidal, exert their impact via various means, originate from a living organism or a laboratory, and appropriately be used in or on living tissue or not. Though the primary focus of this chapter is on resistance to the antimicrobial agents used to treat uropathogenic Escherichia coli (UPEC)-caused urinary tract infections (UTIs), some attention will be given to UPEC’s resistance to silver-containing antiseptics, which may be incorporated into catheters to prevent foreign body-associated UTIs.

Multidrug resistance and extended-spectrum β-lactamases genes among Escherichia coli from patients with urinary tract infections in Northwestern Libya

INTRODUCTION

Multidrug resistance (MDR) and emergence of extended-spectrum β-lactamases (ESBLs) that mediate resistance to β-lactam drugs among Escherichia coli and other uropathogens have been reported worldwide. However, there is little information on the detection of ESBLs genes in E. coli from patients with urinary tract infections (UTIs) in the Arab countries using polymerase chain reaction (PCR), and in Libya such information is lacking.

METHODS

All patients attending Zawiya Teaching Hospital in Zawiya city between November 2012 and June 2013 suspected of having UTIs and from whom midstream urine samples were taken as part of the clinical workup were included in this prospective study. Samples were examined for uropathogens by standard bacteriological procedures. VITEK-2 automated microbiology system was used to identify the isolated uropathogens and determine the susceptibility of E. coli and Klebsiella spp. isolates to antimicrobials. In addition, phenotypically ESBLs-positive E. coli isolates were tested for ESBLs genes by PCR.

RESULTS

The present study enrolled 1,790 patients with UTIs. Uropathogens were found in 371 (20.7%) urine specimens examined. Mixed pathogens were detected in two specimens with 373 total pathogens isolated. E. coli and Klebsiella spp. were the predominant uropathogens at 55.8% (208/373) and 18.5% (69/373), respectively. Other pathogens were detected in 25.7% (96/373) of urine samples. Of the E. coli and Klebsiella spp. tested, 69.2 and 100% were resistant to ampicillin, 6.7 and 33.3% to ceftriaxone, and 23.1 and 17.4% to ciprofloxacin, respectively. MDR (resistance to ≥3 antimicrobial groups) was found in 69 (33.2%) of E. coli and in 29 (42%) of Klebsiella spp. isolates. ESBLs were detected phenotypically in 14 (6.7%) of E. coli and in 15 (21.7%) of Klebsiella spp. isolates. Thirteen out of the 14 phenotypically ESBL-positive E. coli were positive for ESBL genes by PCR. bla TEM gene was detected in seven isolates, bla OXA gene in 10 isolates and bla CTX-M gene in six isolates. bla SHV gene was not detected in the present study.

CONCLUSION

The isolation of MDR ESBL-producing uropathogens undoubtedly will limit the choices clinicians have to treat their patients with UTIs. Therefore, there is an urgent need for surveillance studies on antimicrobial resistance and prevalence of ESBLs among uropathogens to guide the clinical treatment of UTIs in Libya in the future.

Antimicrobial drug resistance among clinically relevant bacterial isolates in sub-Saharan Africa: a systematic review

BACKGROUND

Little is known about the prevalence of antimicrobial resistance (AMR) amongst bacterial pathogens in sub-Saharan Africa (sSA), despite calls for continent-wide surveillance to inform empirical treatment guidelines.

METHODS

We searched PubMed and additional databases for susceptibility data of key pathogens for surveillance, published between 1990 and 2013. Extracted data were standardized to a prevalence of resistance in populations of isolates and reported by clinical syndrome, microorganism, relevant antimicrobial drugs and region.

RESULTS

We identified 2005 publications, of which 190 were analysed. Studies predominantly originated from east sSA (61%), were hospital based (60%), were from an urban setting (73%) and reported on isolates from patients with a febrile illness (42%). Quality procedures for susceptibility testing were described in <50% of studies. Median prevalence (MP) of resistance to chloramphenicol in Enterobacteriaceae, isolated from patients with a febrile illness, ranged between 31.0% and 94.2%, whilst MP of resistance to third-generation cephalosporins ranged between 0.0% and 46.5%. MP of resistance to nalidixic acid in Salmonella enterica Typhi ranged between 15.4% and 43.2%. The limited number of studies providing prevalence data on AMR in Gram-positive pathogens or in pathogens isolated from patients with a respiratory tract infection, meningitis, urinary tract infection or hospital-acquired infection suggested high prevalence of resistance to chloramphenicol, trimethoprim/sulfamethoxazole and tetracycline and low prevalence to third-generation cephalosporins and fluoroquinolones.

CONCLUSIONS

Our results indicate high prevalence of AMR in clinical bacterial isolates to antimicrobial drugs commonly used in sSA. Enhanced approaches for AMR surveillance are needed to support empirical therapy in sSA.

Distribution and antimicrobial susceptibility pattern of bacterial pathogens causing urinary tract infection in urban community of meerut city, India

Urinary tract infection is one of the common infections in the Indian community. Distribution and susceptibility of UTI-causing pathogens change according to time and place. This study was conducted to determine the distribution and antimicrobial susceptibility of uropathogens in the Indian community as well as to determine the effect of gender and age on the etiology of bacterial uropathogens. Clean catch midstream urine samples were collected from 288 patients of the age ranging from 15 to ≥48 years. Antimicrobial susceptibility was performed on all isolated bacteria by Kirby Bauer's disc diffusion method. The multiple antibiotic resistance (MAR) index of each antibiotic was calculated. The UTI prevalence was 53.82% in patients; however, the prevalence was significantly higher in females than in males (females: 73.57%; males: 35.14%; P = 0.000). Females within the age group of 26-36 years and elderly males of ≥48 years showed higher prevalence of UTI. Gram negative bacteria (90.32%) were found in high prevalence than Gram positive (9.68%). Escherichia coli (42.58%) was the most prevalent gram negative isolate. Nitrofurantoin (78.71%) was found the most resistant drug among all uropathogens. Tested carbapenems were found the most susceptible drug against isolated uropathogens which showed 92.26% and 84.52% susceptibility, respectively.

Human bladder uroepithelial cells synergize with monocytes to promote IL-10 synthesis and other cytokine responses to uropathogenic Escherichia coli

Urinary tract infections are a major source of morbidity for women and the elderly, with Uropathogenic Escherichia coli (UPEC) being the most prevalent causative pathogen. Studies in recent years have defined a key anti-inflammatory role for Interleukin-10 (IL-10) in urinary tract infection mediated by UPEC and other uropathogens. We investigated the nature of the IL-10-producing interactions between UPEC and host cells by utilising a novel co-culture model that incorporated lymphocytes, mononuclear and uroepithelial cells in histotypic proportions. This co-culture model demonstrated synergistic IL-10 production effects between monocytes and uroepithelial cells following infection with UPEC. Membrane inserts were used to separate the monocyte and uroepithelial cell types during infection and revealed two synergistic IL-10 production effects based on contact-dependent and soluble interactions. Analysis of a comprehensive set of immunologically relevant biomarkers in monocyte-uroepithelial cell co-cultures highlighted that multiple cytokine, chemokine and signalling factors were also produced in a synergistic or antagonistic fashion. These results demonstrate that IL-10 responses to UPEC occur via multiple interactions between several cells types, implying a complex role for infection-related IL-10 during UTI. Development and application of the co-culture model described in this study is thus useful to define the degree of contact dependency of biomarker production to UPEC, and highlights the relevance of histotypic co-cultures in studying complex host-pathogen interactions.

Quantification of bacterial uropathogens in preclinical samples using real-time PCR assays

Uropathogenic Escherichia coli (UPEC) and Staphylococcus saprophyticus (S. saprophyticus) are responsible for the majority of community-acquired urinary tract infections (UTI). Agar plating, a gold standard for detection of bacterial uropathogens, is labor intensive, limited for distinguishing between environmental contaminants and pathogens, and fails to effectively detect mixed infections. A reliable method for specific and sensitive quantitative assessment of infections would allow cost-effective evaluation of large numbers of experimental samples. A methodology such as quantitative PCR (qPCR) addresses the limitations of agar plating. We developed and validated highly specific and sensitive qPCR assays to assist researchers in the evaluation of potential vaccines and interventions in preclinical models of UPEC and S. saprophyticus UTI. The developed UPEC PCR targeted a highly conserved region of the UPEC hemolysin D (hlyD) gene that reproducibly detected type strains CFT073 and J96 over a 9 log range with high precision. To quantify S. saprophyticus genomes, a separate qPCR assay targeting the Trk transport gene was developed with an 8 log range. Neither assay detected bacterial species predicted to be sample contaminants. Using our optimized workflow that includes automated steps, up to 200 urine or tissue samples can be processed in as few as 3 h. Additionally, sequence comparisons of our primers and probe to other UTI bacterial strains indicated the broad applicability of these assays. These optimized qPCR assays provide a cost-effective and time-saving method for quantification of bacterial burdens in tissues and body fluids to assess the effectiveness of candidate vaccines or interventions.

Associated risk factors of urinary tract infection among pregnant women at Felege Hiwot Referral Hospital, Bahir Dar, North West Ethiopia

BACKGROUND

Urinary tract infections (UTIs) are among the most common bacterial infections in humans, both in the community and hospital settings. It is a serious health problem affecting millions of people each year and is the leading cause of Gram-negative bacteremia. We previously conducted a study on "Urinary Bacterial Profile and Antibiotic Susceptibility Pattern of UTI among Pregnant Women in North West Ethiopia" but the study did not address risk factors associated with urinary tract infection so the aim of the study was to assess associated risk factors of UTI among pregnant women in Felege Hiwot Referral Hospital, Bahir Dar, North West Ethiopia.

METHODS

A total of 367 pregnant women with and without symptoms of urinary tract infection(UTI) were included as a study subject from January 2011 to April 2011. Midstream urine samples were collected and processed following standard bacteriological tests. Data concerning associated risk factors were collected using structured questionnaires and were processed and analyzed using Statistical Package for Social Science (SPSS version 16).

RESULT

Bivarait analysis of socio-demographic characteristics and associated risk factors of UTI showed that family income level (family monthly income level ≤ 500 birr($37.85); P = 0.006, OR = 5.581, CI = 1.658, 18.793 and 501-1000 birr ($37.93-$75.70), P = 0.039, OR = 3.429, CI = 1.065, 11.034), anaemia (P = 0.003, OR = 4.388, CI = 1.776, 10.839), sexual activity (P = 0.032, OR = 3.520, CI = 1.197,10.363) and past history of UTI (P = 0.000, OR = 3.397, CI = 1.672, 6.902) were found to be factors significantly associated with increase prevalence of UTI. In contrast multiparity, history of catheterization, genitourinary abnormality, maternal age, gestational age and educational status were not significantly associated with UTI among pregnant women.

CONCLUSION

In this study UTI was high among pregnant women in the presence of associated risk factor such as anaemia, low income level, past history of UTI and sexual activity.

Evaluation of antimicrobial susceptibility of Enterobacteriaceae causing urinary tract infections in Africa

Our objective was to evaluate the antimicrobial susceptibility of Enterobacteriaceae causing urinary tract infections (UTIs) in adults in Africa. The PubMed database was systematically searched to identify relevant studies published after 2000. Google, World Health Organization, and African Field Epidemiology networks were also searched. Twenty-eight studies, accounting for 381,899 urine isolates from 14 African countries, met the inclusion criteria. Escherichia coli, Klebsiella spp., and Proteus spp. were the most commonly encountered uropathogens. Cefotaxime, imipenem, fosfomycin, and ciprofloxacin were the antibiotics with the highest activity against E. coli isolates from outpatients, with susceptibility being 92 to 99, 100, 100, and 68 to 91%, respectively. The susceptibility among Klebsiella spp. isolates from outpatients varied from 80 to 100% for amikacin and from 53 to 100% for ciprofloxacin, while susceptibility was 74 to 78, 97, and 77% for ciprofloxacin, amikacin, and fosfomycin, respectively, among Klebsiella species isolates from inpatients or patients with hospital-acquired UTIs. With regard to Proteus spp., the highest activity was observed among fluoroquinolones; 71 to 100% of the P. mirabilis isolates were susceptible to ciprofloxacin in four studies, and 74 to 100% of the P. vulgaris isolates were susceptible to ofloxacin in two studies. The currently available evidence suggests that the antimicrobial susceptibility patterns of Enterobacteriaceae uropathogens in African countries were similar to those in countries of southeast Europe. Further original studies are warranted from African countries for which there is limited published data.

Microbiology of urinary tract infections in Gaborone, Botswana

OBJECTIVE

The microbiology and epidemiology of UTI pathogens are largely unknown in Botswana, a high prevalence HIV setting. Using laboratory data from the largest referral hospital and a private hospital, we describe the major pathogens causing UTI and their antimicrobial resistance patterns.

METHODS

This retrospective study examined antimicrobial susceptibility data for urine samples collected at Princess Marina Hospital (PMH), Bokamoso Private Hospital (BPH), or one of their affiliated outpatient clinics. A urine sample was included in our dataset if it demonstrated pure growth of a single organism and accompanying antimicrobial susceptibility and subject demographic data were available.

RESULTS

A total of 744 samples were included. Greater than 10% resistance was observed for amoxicillin, co-trimoxazole, amoxicillin-clavulanate, and ciprofloxacin. Resistance of E. coli isolates to ampicillin and co-trimoxazole was greater than 60% in all settings. HIV status did not significantly impact the microbiology of UTIs, but did impact antimicrobial resistance to co-trimoxazole.

CONCLUSIONS

Data suggests that antimicrobial resistance has already emerged to most oral antibiotics, making empiric management of outpatient UTIs challenging. Ampicillin, co-trimoxazole, and ciprofloxacin should not be used as empiric treatment for UTI in this context. Nitrofurantoin could be used for simple cystitis; aminoglycosides for uncomplicated UTI in inpatients.

Urinary tract infection among symptomatic outpatients visiting a tertiary hospital based in midwestern Nigeria

Microbial pathogens implicated in urinary tract infection and their antibiotic susceptibility patterns as prevalent in UTI symptomatic outpatients resident in Benin City, Nigeria was the focus of this study. One hundred (100) midstream urine samples were collected into sterile plastic universal bottles from outpatients who visited the University of Benin Teaching Hospital, Nigeria and who were tentatively diagnosed as manifesting symptoms of UTI. Patients were referred to the Medical Microbiology department by the consulting doctors. Significant bacterial counts and neutrophil (pus cells) counts were carried out on samples by standard methods. Positive samples for both counts were inoculated aseptically on sterile MacConkey agar, Cystine Lactose Electrolyte Deficient (CLED) agar and Sabouraud Dextrose agar plates and incubated appropriately. Microbial isolates were identified and antibiotic sensitivity testing was carried out on isolates by standard methods. Thirty nine (39.0%) and 61 (61.0%) samples recorded significant microbial growth and no growth respectively. Gram negative bacilli constituted 86.1% (of which enterobacteriaceae made up 49.9%) while gram positive cocci made up 13.9%. Strains of uropathogens isolated were Alcaligenes spp (19.4%), Klebsiella aerogenes (16.7%), Escherichia coli (13.9%), Staphylococcus aureus (13.9%), Candida albicans (11.1%), Proteus mirabilis (8.3%), Pseudomonas aeruginosa (5.5%), Enterobacter spp (5.5%) and Providencia spp (5.5%). Occurrence of UTI in male and female patients were 58.3% and 41.7% respectively of which UTI occurred highest in the 25-46, 15-54 and 27-54 age groups in that decreasing order. Alcaligenes spp occurred most in very old female patients. Candida albicans (the only fungal uropathogen) occurred in an 8day old male patient. Other isolates occurred in much older patients. A significantly high microscopic neutrophil count or pyuria was recorded from deposits of UTI positive patients (i.e. < 5/HPF). Eighteen (representing 50.5%) and 15 (47.8%) of total microbial strains isolated were sensitive to nitrofurantoin and ceftriaxone respectively. Antibiotic susceptibility profile also showed 13(41.6%), 13(41.6%), 13(41.6%) for ciprofloxacin, cefuroxime and ofloxacin respectively suggesting moderate sensitivity of the fluoroquinolones and second/third generation cephalosporins. Gentamicin, ampicillin and augmentin recorded over 70.0% resistance level each. A total of nineteen bacterial strains made of E.coli, Enterobacter spp, Proteus mirabilis, Providencia spp, Staph. aureus and Pseudomonas aeruginosa were multi drug resistant as they resisted 3, 3, 4, 4, 5 and 8 antibiotics respectively.

Antimicrobial resistance of Staphylococcus aureus strains from patients with urinary tract infections in Yenagoa, Nigeria

CONTEXT

Antimicrobial resistance in Staphylococcus aureus infections is a global public health problem resulting in very limited treatment options. This study determined the antimicrobial resistance pattern of S. aureus strains from urinary tract infections (UTIs) to commonly used antimicrobial agents.

MATERIALS AND METHODS

Midstream urine specimens of UTIs symptomatic patients from public and private health institutions in Yenagoa, Nigeria were collected, cultured, and screened for common pathogens using standard microbiological protocols. The antimicrobial susceptibility of identified S. aureus strains was evaluated using disc diffusion and agar dilution techniques.

RESULTS

A total of 46 (33.6%) S. aureus strains were identified from 137 growths of the 200 urine specimens. All the S. aureus isolates were methicillin resistant; they exhibited total resistance to ampicillin, 97.8% to tetracycline, 80.4% to chloramphenicol and co-trimoxazole, 73.9% to gentamicin, 69.6% to augmentin and vancomycin, 54.3% to cefuroxime, 39.1% to nitrofurantoin, 34.8% to ofloxacin, and 32.6% to ciprofloxacin. The isolates were commonly resistant to 7 (77.8%) of the nine classes of antimicrobial agents used in this study and 45 (97.8%) of all the isolates were multi-resistant.

CONCLUSION

The faster rate at which this pathogen is developing resistance to nitrofurantoin and fluoroquinolones is reducing their usefulness in the empiric treatment of uncomplicated UTIs. Thus, the need to adopt new strategies in the control of antibiotic resistance in this country cannot be overemphasized.

Decreased susceptibility to commonly used antimicrobial agents in bacterial pathogens isolated from urinary tract infections in Rwanda: need for new antimicrobial guidelines

The aim of this study was to obtain data on susceptibility patterns of pathogens responsible for both community and hospital urinary tract infections (UTIs); and analyzed risk factors for infection caused by ciprofloxacin-resistant Escherichia coli and extended-spectrum β-lactamase (ESBL)-producing strains in Rwanda. Of 1,012 urine cultures prospectively studied, a total of 196 (19.3%) yielded significant growth of a single organism. The most common isolate (60.7%) was Escherichia coli. The antibiotics commonly used in UTIs are less effective except Fosfomycin-trometamol and imipinem. The use of ciprofloxacin in the previous 6 months (odds ratio [OR] = 7.59 [1.75-32.74]), use of other antibiotics in the previous 6 months (OR = 1.02 [1.02-2.34]), and production of ESBL (OR = 19.32 [2.62-142.16]) were found to be associated with ciprofloxacin resistance among the E. coli isolates. Risk factors for ESBL positivity were the use of ciprofloxacin and third-generation cephalosporin in the preceding 6 months (OR = 3.05 [1.42-6.58] and OR = 9.78 [2.71-35.25], respectively); and being an inpatient (OR = 2.27 [1.79-2.89]). Fosfomycin-trometamol could be included as a reasonable alternative for the therapy of uncomplicated UTI in Rwanda.

Efficacy of combination use of Beta-lactamase inhibitor with penicillin and fluoroquinolones for antibiotic prophylaxis in transrectal prostate biopsy

Purpose

To investigate the efficacy of tazobactam/piperacillin (TAZ/PIPC) plus levofloxacin (LVFX) as a prophylactic administration in transrectal prostate biopsy (TPBX).

Materials and Methods

We investigated 201 consecutive patients who underwent TPBX in one Japanese hospital during the period of 2009-2010. The patients received TAZ/PIPC 4.5 g i.v. once just before and 3 hours after TPBX, plus oral LVFX 300 mg or 500 mg daily for 3 days. We examined the infectious adverse events and laboratory data (serum white blood cell [WBC] count and C-reactive protein [CRP]) before and 1 day after TPBX.

Results

Only one patient (0.50%) in 201 cases had febrile complications after TPBX. Serum WBC and CRP did not rise significantly on the day after TPBX compared with before TPBX (p>0.05). There was no significant difference in the rise of serum WBC and CRP before and after TPBX in the comparison of LVFX 500 mg with LVFX 300 mg in the TAZ/PIPC plus LVFX regimen.

Conclusions

TAZ/PIPC plus LVFX can be considered as a prophylactic regimen for preventing infectious complications in TPBX.

Identification of in vivo-induced antigens including an RTX family exoprotein required for uropathogenic Escherichia coli virulence

Uncomplicated urinary tract infections (UTI) are caused most commonly by uropathogenic Escherichia coli (UPEC). Whole-genome screening approaches, including transcriptomic, proteomic, and signature-tagged mutagenesis, have shown that UPEC highly expresses or requires genes for translational machinery, capsule, lipopolysaccharide, type 1 fimbriae, and iron acquisition systems during UTI. To identify additional genes expressed by UPEC during UTI, an immunoscreening approach termed in vivo-induced antigen technology (IVIAT) was employed to identify antigens produced during experimental infection that are not produced during in vitro culture. An inducible protein expression library, constructed from genomic DNA isolated from UPEC strain CFT073, was screened using exhaustively adsorbed pooled sera from 20 chronically infected female CBA/J mice. Using this approach, we identified 93 antigens induced by UPEC in vivo. A representative subset of these genes was tested by quantitative PCR for expression by CFT073 in vivo and during growth in human urine or LB medium in vitro; proWX, narJI, lolA, lolD, tosA (upxA), c2432, katG, ydhX, kpsS, and yddQ were poorly expressed in vitro but highly expressed in vivo. Of these, tosA, a gene encoding a predicted repeat-in-toxin family member, was expressed exclusively during UTI. Deletion of tosA in UPEC strain CFT073 resulted in significant attenuation in bladder and kidney infections during ascending UTI. By screening for in vivo-induced antigens, we identified a novel UPEC virulence factor and additional proteins that could be useful as potential vaccine targets.

Self-medication with antibiotics for the treatment of menstrual symptoms in Southwest Nigeria: a cross-sectional study

Background

Self-medication with antibiotics is an important factor contributing to the development of bacterial antibiotic resistance. The purpose of this study was to evaluate the prevalence of self-medication with antibiotics for the treatment of menstrual symptoms among university women in Southwest Nigeria.

Methods

A cross-sectional survey was administered to female undergraduate and graduate students (n = 706) at four universities in Southwest Nigeria in 2008. The universities were selected by convenience and the study samples within each university were randomly selected cluster samples. The survey was self-administered and included questions pertaining to menstrual symptoms, analgesic and antibiotic use patterns, and demographics. Data were analyzed using descriptive statistics and logistic regression.

Results

The response rate was 95.4%. Eighty-six percent (95% CI: 83-88%) of participants experienced menstrual symptoms, and 39% (95% CI: 36-43%) reported using analgesics to treat them. Overall, 24% (95% CI: 21-27%) of participants reported self-medicated use of antibiotics to treat the following menstrual symptoms: cramps, bloating, heavy bleeding, headaches, pimples/acne, moodiness, tender breasts, backache, joint and muscle pain. Factors associated with this usage were: lower levels of education (Odds Ratio (OR): 2.8, 95% CI: 1.1-7.1, p-value: 0.03); non-science major (OR: 1.58, 95% CI: 1.03-2.50, p-value: 0.04); usage of analgesics (OR: 3.17, 95% CI: 2.07-4.86, p-value: <0.001); and mild to extreme heavy bleeding (OR: 1.64, 95% CI: 1.01-2.67, p-value: 0.05) and pimples/acne (OR: 1.57, 95% CI: 0.98-2.54, p-value: 0.06). Ampicillin, tetracycline, ciprofloxacin and metronidazole were used to treat the most symptoms. Doctors or nurses (6%, 95% CI: 4-7%), friends (6%, 95% CI: 4-7%) and family members (7%, 95% CI: 5-8%) were most likely to recommend the use of antibiotics for menstrual symptoms, while these drugs were most often obtained from local chemists or pharmacists (10.2%, 95% CI: 8-12%).

Conclusions

This is the first formal study to report that approximately 1 out of 4 university women surveyed in Southwest Nigeria self-medicate with antibiotics to treat menstrual symptoms. This practice could provide monthly, low-dose exposures to antibiotics among users. Further studies are necessary to evaluate the impacts of self-medication on student health.