Antimicrobial Drug Susceptibility Research Articles

Natural resistance to meglumine antimoniate is associated with treatment failure in cutaneous leishmaniasis caused by Leishmania (Viannia) panamensis.

The multifactorial basis of therapeutic response can obscure the relation between antimicrobial drug susceptibility and clinical outcome. To discern the relationship between parasite susceptibility to meglumine antimoniate (SbV) and therapeutic outcome of cutaneous leishmaniasis, risk factors for treatment failure were considered in evaluating this relationship in ninety-one cutaneous leishmaniasis patients and corresponding clinical strains of Leishmania (Viannia) panamensis. Parasite susceptibility to 32 μg SbV/mL (plasma Cmax) was evaluated in primary human macrophages, PBMCs, and U937 macrophages. Early parasitological response to treatment was determined in lesions of a subgroup of patients, and pathogenicity of Sb-resistant and sensitive clinical strains was compared in BALB/c mice. Parasite survival in cell models and patient lesions was determined by qRT-PCR of Leishmania 7SLRNA transcript. Parasite loads in BALB/c mice were quantified by limiting dilution analysis. The disparate Sb-susceptibility of parasite subpopulations distinguished by isoenzyme profiles (zymodemes) was manifest in all cell models. Notably, Sb-resistance defined by parasite survival, was most effectively discerned in U937 macrophages compared with primary human host cells, significantly higher among strains from patients who failed treatment than cured and, significantly associated with treatment failure. Each unit increase in transformed survival rate corresponded to a 10.6-fold rise in the odds of treatment failure. Furthermore, treatment failure was significantly associated with naturally Sb-resistant zymodeme 2.3 strains, which also produced larger lesions and parasite burdens in BALB/c mice than Sb-sensitive zymodeme 2.2 strains. The confounding effect of host risk factors for treatment failure in discerning this association was evidenced in comparing strains from patients with and without the defined risk factors for treatment failure. These results establish the association of natural resistance to meglumine antimoniate with treatment failure, the importance of host risk factors in evaluating drug susceptibility and treatment outcome, and the clinical and epidemiological relevance of natural Sb-resistance in L. (V.) panamensis subpopulations.

Antimicrobial Drug Susceptibility Test of Pythium insidiosum by Disc Diffusion Method

Background: Pythiosis is a life-threatening disease caused by the fungus-like organism Pythium insidiosum. It causes disease in both animals and humans. Amphotericin B antifungal is less effective because it lacks ergosterol, a drug target in the cell membrane. Objective: To evaluate antimicrobial susceptibility test of P. insidiosum isolated from human pythiosis by disc diffusion method. Methods: The antimicrobial drug susceptibility test by disc diffusion method was tested against 10 clinical isolated strains of P. insidiosum. Antimicrobial drugs comprise of 8 antibiotics (chloramphenicol, cefotaxime, ciprofloxacin, gentamycin, tetracycline, meropenem, oxacillin, and vancomycin) and 2 antifungal drugs (itraconazole and amphotericin B) which were included in the test. Results: Antimicrobial drugs susceptibility tests were performed on 10 clinically isolated strains of P. insidiosum. Six of them showed susceptibility to antimicrobial drugs. The cutaneous pythiosis strain (SIMI 8569) showed the highest number of susceptibilities to antimicrobial agents (chloramphenicol, ciprofloxacin, gentamycin, tetracycline, vancomycin, and itraconazole). In addition, 4 strains of P. insidiosum (M 29, SIMI 6666, SIMI 7873, and SIMI 2989-42) were not inhibited by all antimicrobial drugs. Conclusions: This result concluded that chloramphenicol, tetracycline, and itraconazole inhibited the mycelial growth of P. insidiosum better than the other drugs. The inhibition effects of these drugs were observed in 40% - 60% of the strains. Further experiments should be carried out to evaluate the tested drugs in various concentrations with other more susceptible methods to get more precise concentrations exposed to P. insidiosum isolates such as broth dilution or dilution assays.

Nanopore sequencing of infectious fluid is a promising supplement for gold-standard culture in real-world clinical scenario.

Infectious diseases are major causes of morbidity and mortality worldwide, necessitating the rapid identification and accurate diagnosis of pathogens. While unbiased metagenomic next-generation sequencing (mNGS) has been extensively utilized in clinical pathogen identification and scientific microbiome detection, there is limited research about the application of nanopore platform-based mNGS in the diagnostic performance of various infectious fluid samples. In this study, we collected 297 suspected infectious fluids from 10 clinical centers and detected them with conventional microbiology culture and nanopore platform-based mNGS. The objective was to assess detective and diagnostic performance of nanopore-sequencing technology (NST) in real-world scenarios. Combined with gold-standard culture and clinical adjudication, nanopore sequencing demonstrated nearly 100% positive predictive agreements in microbial-colonized sites, such as the respiratory and urinary tracts. For samples collected from initially sterile body sites, the detected microorganisms were highly suspected pathogens, and the negative predictive agreements were relatively higher than those in the microbial-colonized sites, particularly with 100% in abscess and 95.7% in cerebrospinal fluid. Furthermore, consistent performance was also observed in the identification of antimicrobial resistance genes and drug susceptibility testing of pathogenic strains of Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii. Rapid NST is a promising clinical tool to supplement gold-standard culture, and it has the potential improve patient prognosis and facilitate clinical treatment of infectious diseases.

Microbiological Distribution, Antimicrobial Susceptibility and Risk Factors of Polymicrobial Infections in Diabetic Foot.

Diabetic foot infection (DFI) leads to poor prognosis and polymicrobial infections are usually the main cause. The study is to explore the microbiological distribution, antimicrobial drug susceptibility, and risk factors of polymicrobial infections in hospitalized patients with DFI. This retrospective study included 160 patients with DFI in Wagner's grades 2, 3, and 4. Deep necrotic tissue was used to acquire specimens for microbiological culture. VITEK-2 system and MALDI-TOF mass spectrometry were used to identify the bacterial isolates. The Kirby Bauer method was used for drug susceptibility tests. A total of 202 pathogens were isolated. The proportion of gram-negative bacilli (GNB, 62.4%, 126 of 202) was higher than that of gram-positive cocci (GPC, 37.6%, 76 of 202). The most prevalent GPC was Staphylococcus aureus in every Wagner grade, while the most common GNB varied in different Wagner grades. Linezolid was the most effective antibiotic for GPC in different Wagner grades. Imipenem was the most effective antibiotic for GNB in Wagner grade 2. Amikacin was the most effective antibiotic for GNB in Wagner grades 3 and 4. Polymicrobial infections existed only in Wagner grades 3 and 4 and increased the risk of amputation (p < 0.01). History of antibiotics, duration of diabetic foot, CRP, and lower extremity arterial disease were the independent risk factors of polymicrobial infections (p < 0.05). Clinicians should adjust the antibiotic as needed based on the results of drug susceptibility and clinical treatment effect among different Wagner grades. Particular attention should be given to the treatment of polymicrobial infections.

Isolation, Identification and Drug Resistance Rates of Bacteria from Pigs in Zhejiang and Surrounding Areas during 2019-2021.

This study aimed to determine the prevalence of bacterial diseases in pig farms in various regions of Zhejiang Province and surrounding areas. A total of 526 samples were collected from 85 pig farms in Zhejiang Province and surrounding areas. In this study, samples were analyzed using bacterial isolation and purification, Gram staining, PCR amplification, and antimicrobial susceptibility testing. A total of 36 Pasteurella multocida (Pm) isolates were detected, with an isolation rate of 6.84%; 37 Bordetella bronchiseptica (Bb) isolates were detected, with an isolation rate of 7.03%; 60 Glasserella parasuis (G. parasuis) isolates were detected, with an isolation rate of 11.41%; 170 Escherichia coli (E. coli) isolates were detected, with an isolation rate of 32.32%; 67 Streptococcus suis (SS) isolates were detected, with an isolation rate of 12.74%; 44 Actinobacillus pleuropneumoniae (APP) isolates were detected, with an isolation rate of 8.37%; and 7 Salmonella enteritis (SE) isolates were detected, with an isolation rate of 1.33%. Antimicrobial drug susceptibility testing against 21 types of antibiotics was carried out on the isolated strains, and the results showed that 228 strains had varying degrees of resistance to 21 antibiotics, including Pm, Bb, E. coli, and APP, with the highest resistance to lincomycin, at 100%. Pm and APP were the most sensitive to cephalothin, with resistance rates of 0. In terms of strains, Pm had the highest overall sensitivity to 21 antibiotics, and E. coli had the highest resistance. In short, bacterial diseases in Zhejiang and the surrounding areas were harmful, and the drug resistance situation was severe. This study provides scientific guidance for the clinical treatment of bacterial diseases.

Co-occurrence of blaNDM-1, rmtC, and mcr-9 in multidrug-resistant Enterobacter kobei strain isolated from an infant with urinary tract infection

The co-emergence of mcr and carbapenem resistance genes in Gram-negative bacteria is a serious problem. This study aims to clarify the genetic characteristic of one novel multidrug-resistant Enterobacter kobei EC1382 with mcr-9 causing urinary tract inflammation in an infant. Antimicrobial drug susceptibility testing was performed for this isolate using the broth microdilution method. Whole-genome sequencing was performed using the Illumina PacBio RS II platform and HiSeq platform, and the antimicrobial resistance genes, mobile elements, and plasmid replicon types were identified. Conjugation analysis was performed using Escherichia coli C600 as recipients. Enterobacter kobei EC1382 was resistant to carbapenem, aminoglycoside, and cephalosporin. Twenty-five antimicrobial resistance genes were identified, including genes conferring resistance to carbapenem (blaNDM-1), colistin (mcr-9), and aminoglycosides (rmtC). The blaNDM-1 gene, accompanied by bleMBL and rmtC located downstream of an ISCR14 element, was detected in the IncFII(Yp) type plasmid pEC1382-2. Interestingly, although E. kobei EC1382 was susceptible to colistin, it had three identical mcr-9 genes (two in the chromosome and one in the IncHI2-type plasmid pEC1382-1). The backbone (∼12.2-kb genetic fragment) of these mcr-9 (flanked by IS903B and IS481-IS26) regions were conserved in this strain, and they were found to be present in various bacteria as three types, implying a silent distribution. To the best of our knowledge, this is the first study to demonstrate the coexistence of blaNDM-1, rmtC, and mcr-9 in E. kobei. The silent prevalence of mcr-9 in bacteria may be a threat to public health.

Evaluation of antimicrobial susceptibility of Escherichia coli isolated from contaminated areas of Majengo slum in Meru County, Kenya

Background: Antimicrobial drug resistance is of great concern today. Infections by the antimicrobial resistant strains of Escherichia coli, including enteropathogenic as well as enterotoxigenic strains have been reported as a major cause of deaths, especially among young children in low- and middle-income countries. This has been augmented by antimicrobial misuse, over the counter availability and poor sanitation especially in low income areas. This study aimed at characterizing antimicrobial resistant strains of Escherichia coli isolated from sanitation environments of the Majengo slum in Meru County, Kenya Methods: A cross-sectional study was conducted on 61 samples from soil, water and drains swabs. These were tested against five antimicrobial drugs by the Kirby disk diffusion method. Results: A total of 42 (69%) of the samples had Escherichia coli. These recorded antimicrobial drug susceptibility as follows: Out of the five antimicrobial agents used, ceftazidime 28 (66.67%) showed the highest sensitivity followed by ciprofloxacin 26 (61.90%) and imepenem 25 (59.52%) respectively. cefotaxime and cefoxitin showed least sensitivity at 14 (33.33%) and 13 (30.95%) respectively. In intermediate imepenem and ciprofloxacin were the highest with 12 (28.57%) followed by cefotaxime 10 (23.81%). The least intermediate was observed in ceftazidime and cefoxitin both at 7 (16.67%). The highest resistance was observed in cefoxitin 22 (52.38%), followed by cefotaxime at 18 (42.86%). Ciprofloxacin, imepenem and ceftazidime had the lowest resistance 4 (9.52%), 5 (11.91%) and 7 (16.67%) respectively. The p-value &lt;0.05 was considered significant to the study. Conclusions: This study showed that Escherichia coli isolated from Majengo is pathogenic and resistant to antibiotics. Detection of Escherichia coli poses a great risk in the spread of resistant strains in human. Proper sanitation and hygiene awareness practices should be provided through education to the residents of this area.

Prevalence of antimicrobial resistance and virulence genes in Klebsiella pneumoniae and Congenetic Raoultella Isolates from captive giant pandas.

To study antimicrobial resistance and virulence genes of Klebsiella pneumoniae and Raoultella strains isolated from captive giant pandas. Non-duplicate fecal samples were collected from 128 giant pandas during 2017-2019. All isolated microbial strains were tested for antimicrobial drug susceptibility using BD verification panels. Four extended-spectrum β-lactamase resistance genes, nine virulence genes and six capsular serotype genes were detected using PCR. 42 K. pneumoniae and nine Raoultella strains were isolated from different giant pandas. Antibiotic resistance rates were 1.9%-23.5%, except for ampicillin, and 7.8% of the isolates were multidrug-resistant to 7-10 antibiotic classes. This is the first time that a multidrug-resistant R. ornithinolytica strain has been isolated from captive giant pandas. The blaTEM, blaCTX-M, blaSHV and blaDHA genes were detected in four MDR ESBL- K. pneumoniae strains. The rmpA, iutA, ybtS, iroN and iroB genes were positively detected in 11.7% of the isolates. Capsular serotype (K2, K5, K54 and K57) genes were all detected in four K. pneumoniae strains, and one was identified as hypervirulent. This study showed that MDR ESBL- K. pneumoniae, hypervirulent K. pneumoniae, MDR R. ornithinolytica and the colistin-resistant strain may pose risks to captive giant pandas and their keepers, and that the diversity of antibiotic resistance and virulence genes in Klebsiella and Raoultella should be monitored regularly.

The Genotypic and Phenotypic Characteristics Contributing to Flomoxef Sensitivity in Clinical Isolates of ESBL-Producing E. coli Strains from Urinary Tract Infections.

We carried out a molecular biological analysis of extended-spectrum β-lactamase (ESBL)-producing E. coli strains and their sensitivity to flomoxef (FMOX). Sequence type (ST) analysis by multilocus sequence typing (MLST) and classification of ESBL genotypes by multiplex PCR were performed on ESBL-producing E. coli strains isolated from urine samples collected from patients treated at our institution between 2008 and 2018. These sequences were compared with results for antimicrobial drug susceptibility determined using a micro-liquid dilution method. We also analyzed cases treated with FMOX at our institution to examine its clinical efficacy. Of the 911 E. coli strains identified, 158 (17.3%) were ESBL-producing. Of these, 67.7% (107/158) were strain ST-131 in ST analysis. Nearly all (154/158; 97.5%) were CTX-M genotypes, with M-14 and M-27 predominating. The isolated strains were sensitive to FMOX in drug susceptibility tests. Among the patient samples, 33 cases received FMOX, and of these, 5 had ESBL-producing E. coli. Among these five cases, three received FMOX for surgical prophylaxis as urinary carriers of ESBL-producing E. coli, and postoperative infections were prevented in all three patients. The other two patients received FMOX treatment for urinary tract infections. FMOX treatment was successful for one, and the other was switched to carbapenem. Our results suggest that FMOX has efficacy for perioperative prophylactic administration in urologic surgery involving carriers of ESBL-producing bacteria and for therapeutic administration for urinary tract infections. Use of FMOX avoids over-reliance on carbapenems or β-lactamase inhibitors and thus is an effective antimicrobial countermeasure.

Virulence gene detection and antimicrobial resistance analysis of Enterococcus faecium in captive giant pandas (Ailuropoda melanoleuca) in China

BackgroundThe emergence of multidrug resistance among enterococci makes effective treatment of enterococcal infections more challenging. Giant pandas (Ailuropoda melanoleuca) are vulnerable to oral trauma and lesions as they feast on bamboo. Enterococci may contaminate such oral lesions and cause infection necessitating treatment with antibiotics. However, few studies have focused on the virulence and drug resistance of oral-derived enterococci, including Enterococcus faecium, in giant pandas. In this study, we analyzed the prevalence of 8 virulence genes and 14 drug resistance genes in E. faecium isolates isolated from saliva samples of giant pandas held in captivity in China and examined the antimicrobial drug susceptibility patterns of the E. faecium isolates.ResultsTwenty-eight isolates of E. faecium were successfully isolated from the saliva samples. Four virulence genes were detected, with the acm gene showing the highest prevalence (89%). The cylA, cpd, esp, and hyl genes were not detected. The isolated E. faecium isolates possessed strong resistance to a variety of drugs; however, they were sensitive to high concentrations of aminoglycosides. The resistance rates to vancomycin, linezolid, and nitrofurantoin were higher than those previously revealed by similar studies in China and other countries.ConclusionsThe findings of the present study indicate the drugs of choice for treatment of oral E. faecium infection in the giant panda.

Evaluation of antimicrobial susceptibility of Escherichia coli isolated from contaminated areas of Majengo slum in Meru County, Kenya

Background: Antimicrobial drug resistance is of great concern today. Infections by the antimicrobial resistant strains of Escherichia coli, including enteropathogenic as well as enterotoxigenic strains have been reported as a major cause of deaths, especially among young children in low- and middle-income countries. This has been augmented by antimicrobial misuse, over the counter availability and poor sanitation especially in low income areas. This study aimed at characterizing antimicrobial resistant strains of Escherichia coli isolated from sanitation environments of the Majengo slum in Meru County, Kenya Methods: A cross-sectional study was conducted on 61 samples from soil, water and drains swabs. These were tested against five antimicrobial drugs by the Kirby disk diffusion method. Results: A total of 42 (69%) of the samples had Escherichia coli. These recorded antimicrobial drug susceptibility as follows: Out of the five antimicrobial agents used, ceftazidime 28 (66.67%) showed the highest sensitivity followed by ciprofloxacin 26 (61.90%) and imepenem 25 (59.52%) respectively. cefotaxime and cefoxitin showed least sensitivity at 14 (33.33%) and 13 (30.95%) respectively. In intermediate imepenem and ciprofloxacin were the highest with 12 (28.57%) followed by cefotaxime 10 (23.81%). The least intermediate was observed in ceftazidime and cefoxitin both at 7 (16.67%). The highest resistance was observed in cefoxitin 22 (52.38%), followed by cefotaxime at 18 (42.86%). Ciprofloxacin, imepenem and ceftazidime had the lowest resistance 4 (9.52%), 5 (11.91%) and 7 (16.67%) respectively. The p-value &lt;0.05 was considered significant to the study. Conclusions: This study showed that Escherichia coli isolated from Majengo is pathogenic and resistant to antibiotics. Detection of Escherichia coli poses a great risk in the spread of resistant strains in human. Proper sanitation and hygiene awareness practices should be provided through education to the residents of this area.

Identification and Antimicrobial Susceptibilities for Patients with Non-tuberculous Mycobacteria Infection in Jeju Island: Single-Center Retrospective Study.

The distribution of species and characteristics of non<bold>-</bold>tuberculous mycobacteria (NTM) differ, and surveillance data for changes in antimicrobial susceptibilities of NTM is insufficient. This study analyzed the changes in antimicrobial susceptibility trends across NTM species and assessed the appropriateness of empirical antimicrobial drugs for NTM. We retrospectively analyzed the clinical characteristics, including demographics, distribution of NTM species, antimicrobial drug susceptibilities, and outcomes, at a teaching hospital in Jeju Island from 2009 - 2022. Overall, 342 patients were included in the analysis; 93.0% were classified into the pulmonary group (PG) and 7.0% into the extrapulmonary group (EPG). The isolation rate of Mycobacterium avium was significantly higher in PG (36.8% vs. 0%, P = 0.001), while that of Mycobacterium fortuitum was significantly higher in EPG (4.5% vs. 31.3%, P = 0.001). The antimicrobial susceptibility rate is higher against clarithromycin (89.9%) and amikacin (83.3%) and lower against rifampin (54.7%) and ethambutol (28.1%). The susceptibility rate to clarithromycin was over 80%, but those to rifampin and ethambutol showed decreasing annual trends. Of the 162 patients who received empirical antimicrobial therapy, actual antimicrobial susceptibility rates were high (90.1%) using empirical macrolide, and relatively low using ethambutol and rifampin (28.0% and 58.8%, respectively). This is the first study of analysis of the distribution, baseline characteristics, and antimicrobial susceptibility of isolated NTM species in pulmonary and extrapulmonary patients in Jeju Island over 10 years. Policies that continuously monitor changes in susceptibility rate are required to ensure effective treatment strategies.

Antimicrobial Resistance Profile of Common Foodborne Pathogens Recovered from Livestock and Poultry in Bangladesh.

Multidrug-resistant (MDR) foodborne pathogens have created a great challenge to the supply and consumption of safe & healthy animal-source foods. The study was conducted to identify the common foodborne pathogens from animal-source foods & by-products with their antimicrobial drug susceptibility and resistance gene profile. The common foodborne pathogens Escherichia coli (E. coli), Salmonella, Streptococcus, Staphylococcus, and Campylobacter species were identified in livestock and poultry food products. The prevalence of foodborne pathogens was found higher in poultry food & by-product compared with livestock (p &lt; 0.05). The antimicrobial drug susceptibility results revealed decreased susceptibility to penicillin, ampicillin, amoxicillin, levofloxacin, ciprofloxacin, tetracycline, neomycin, streptomycin, and sulfamethoxazole-trimethoprim whilst gentamicin was found comparatively more sensitive. Regardless of sources, the overall MDR pattern of E. coli, Salmonella, Staphylococcus, and Streptococcus were found to be 88.33%, 75%, 95%, and 100%, respectively. The genotypic resistance showed a prevalence of blaTEM, blaSHV, blaCMY, tetA, tetB, sul1, aadA1, aac(3)-IV, and ereA resistance genes. The phenotype and genotype resistance patterns of isolated pathogens from livestock and poultry had harmony and good concordance, and sul1 & tetA resistance genes had a higher prevalence. Good agricultural practices along with proper biosecurity may reduce the rampant use of antimicrobial drugs. In addition, proper handling, processing, storage, and transportation of foods may decline the spread of MDR foodborne pathogens in the food chain.

Evaluation of antimicrobial susceptibility of Escherichia coli isolated from contaminated areas of Majengo slum in Meru County, Kenya

Background: Antimicrobial drug resistance is of great concern today. Infections by the antimicrobial resistant strains of Escherichia coli, including enteropathogenic as well as enterotoxigenic strains have been reported as a major cause of deaths, especially among young children in low- and middle-income countries. This has been augmented by antimicrobial misuse, over the counter availability and poor sanitation especially in low income areas. This study aimed at characterizing antimicrobial resistant strains of Escherichia coli isolated from sanitation environments of the Majengo slum in Meru County, Kenya Methods: A cross-sectional study was conducted on 61 samples from soil, water and drains swabs. These were tested against five antimicrobial drugs by the Kirby disk diffusion method. Results: A total of 42 (69%) of the samples had Escherichia coli. These recorded antimicrobial drug susceptibility as follows: Out of the five antimicrobial agents used, ceftazidime 28 (66.67%) showed the highest sensitivity followed by ciprofloxacin 26 (61.90%) and imepenem 25 (59.52%) respectively. cefotaxime and cefoxitin showed least sensitivity at 14 (33.33%) and 13 (30.95%) respectively. In intermediate imepenem and ciprofloxacin were the highest with 12 (28.57%) followed by cefotaxime 10 (23.81%). The least intermediate was observed in ceftazidime and cefoxitin both at 7 (16.67%). The highest resistance was observed in cefoxitin 22 (52.38%), followed by cefotaxime at 18 (42.86%). Ciprofloxacin, imepenem and ceftazidime had the lowest resistance 4 (9.52%), 5 (11.91%) and 7 (16.67%) respectively. The p-value &lt;0.05 was considered significant to the study. Conclusions: This study showed that Escherichia coli isolated from Majengo is pathogenic and resistant to antibiotics. Detection of Escherichia coli poses a great risk in the spread of resistant strains in human. Proper sanitation and hygiene awareness practices should be provided through education to the residents of this area.

Bacterial Profile and Antibiogram of Pathogens Causing Surgical Site Infections at Mnazi Mmoja Hospital in Zanzibar, Tanzania

A hospital based cross sectional study was done to determine bacterial profile and antibiogram of pathogens causing surgical site infections at Mnazi Mmoja Hospital in Zanzibar, Tanzania. The study was conducted from May to July 2017. We enrolled a total of 121 patients who underwent different surgical procedures and met study inclusion criteria. Pus swabs were collected and cultured as per standard operating procedures. Bacterial identification was then performed using biochemical tests and Analytical Profile Index test for Enterobacteriaceae (API 20E). Antimicrobial drug susceptibility testing was performed using Kirby Bauer disc diffusion technique. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 21.0. Of 121 patients that were enrolled in the study, 75 (62%) developed surgical site infection (SSI). A total of 106 isolates were recovered from patients with positive culture results. The majority of the isolates, 92/106 (87%) were Gram-negative bacteria. The most predominant bacterium was Pseudomonas aeruginosa, 29/106 (27%) in all surgical Departments. Some of the isolated pathogens were multi-drug resistant (29/106; 27%), including Extended Spectrum Beta Lactamase (ESBL) producers (24/92; 26%), Methicillin Resistant Stahylococcus aureus (MRSA) (3/9; 33%) and Induced Clindamycin Resistance (ICR) strains (2/14; 14%). K. pneumoniae isolates showed the highest resistance towards most tested antibiotics (24.1-100%), and 24% of P. aeruginosa isolates were resistant to meropenem. In conclusion, P. aeruginosa was the most common isolated pathogen from patients with SSI in Zanzibar and the majority of the pathogens showed high resistance to commonly prescribed antimicrobial agents used in the hospital settings.

Searching for new therapeutic options for the uncommon pathogen Mycobacterium chimaera: an open drug discovery approach

SummaryBackgroundMycobacterium chimaera is a slowly growing non-tuberculous mycobacterium associated with outbreaks of fatal infections in patients after cardiac surgery, and it is increasingly being detected in patients with chronic lung conditions. M chimaera can cause disseminated disease, osteomyelitis, and chronic skin or soft-tissue infections. We aimed to find new inhibitory compounds and drug repurposing opportunities for M chimaera, as current therapeutic options often result in poor outcomes.MethodsIn an open drug discovery approach, we screened the Medicines for Malaria Venture (MMV) Pathogen Box to assess the in-vitro antimicrobial drug susceptibility of M chimaera compared with the antimicrobial drug susceptibility of the slowly growing, major human pathogen Mycobacterium tuberculosis, and the rapidly growing Mycobacterium abscessus reference strains. Compounds identified from an initial resazurin microtitre cell viability assay screen were further characterised by determining the minimum inhibitory concentration (MIC) of MMV Pathogen Box compounds against M chimaera; and the MICs of a panel of 20 drugs commonly used to treat mycobacterial infections against M tuberculosis, M abscessus, and M chimaera. We also assessed the time-kill kinetics of doxycycline, clarithromycin, ethambutol, and rifabutin against M chimaera.FindingsM chimaera was inhibited by 21 (5%) of 400 compounds in the Pathogen Box. Ten compounds were active against all three mycobacteria. MMV675968, with activity against slowly growing mycobacteria that probably targets folate metabolism, had a mean MIC of 2·22 μM (0·80 μg/mL) against M chimaera. Antimicrobial susceptibility testing showed that oxazolidinones such as linezolid (mean MIC 3·13 μg/mL) were active against M chimaera and that bedaquiline was the most potent compound (mean MIC 0·02 μg/mL). Doxycycline, a broad-spectrum antimicrobial drug with excellent tissue penetration properties, also inhibited M chimaera with a mean MIC of 6·25 μg/mL.InterpretationMolecular diagnostics present an opportunity for more effective, targeted drug therapies—treating bacterial infections at the species level. Using an open drug discovery platform, we identified compounds that inhibit the newly recognised pathogen M chimaera. The existing evidence base is poor and the option for expensive drug discovery is improbable; therefore, we have also found options for drug repurposing. Future in-vivo efficacy studies will reveal whether these findings result in new, targeted treatment regimens for M chimaera.FundingWellcome Trust, National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), and the University of Sussex Junior Research Associate scheme.

Association of bacterial isolates and antimicrobial susceptibility between prostatic fluid and urine samples in canine prostatitis with concurrent cystitis

Most old, intact male dogs usually have prostate disorders, especially benign prostatic hypertrophy and prostatitis with or without abscesses, and concurrent cystitis. The successful treatment of dogs with prostatitis concurrent with cystitis has relied on choosing an appropriate antimicrobial drug based on a bacterial culture and drug sensitivity testing. The objective of the study was to compare the prevalence of bacterial species and results of drug susceptibility testing of bacteria that were isolated from the prostatic fluids and urine samples that were collected from dogs with both prostatitis and cystitis. One hundred and sixty intact male dogs, who presented with both diseases, were recruited for the study. The disease diagnoses were based on clinical history notes, physical examinations, abdominal ultrasonography, prostatic fluid cytology, urinalysis and bacterial cultures from both prostatic fluid and urine samples. The bacterial culture results demonstrated that the major species that were detected in either the prostatic fluid or urine samples were Staphylococcus spp., Escherichia coli, Pseudomonas spp., Streptococcus spp., Proteus mirabilis and Klebsiella pneumoniae. Staphylococcus spp. (26.5 %, 43/162) and Escherichia coli (26.1 %, 12/46) were the most prevalent species from the prostatic fluid and urine samples, respectively. Statistical tests revealed that there were no significantly different prevalence levels among the isolated bacteria between the prostatic fluid and urine samples.Imipenem and gentamicin were the most potent antimicrobial drugs tested against the bacterial isolates in the present study. However, the administration of imipenem to treat prostatitis and cystitis in dogs was of concern. Interestingly, there were no significant differences in the antimicrobial drug susceptibility trends between the prostatic fluid and urine samples. Based on these results, a urine sample might be considered as an optional sample for bacterial cultures and antimicrobial drug susceptibility testing when it is not possible to collect a prostatic fluid sample.

Over-Expression of Hypochlorite Inducible Major Facilitator Superfamily (MFS) Pumps Reduces Antimicrobial Drug Susceptibility by Increasing the Production of MexXY Mediated by ArmZ in Pseudomonas aeruginosa.

Pseudomonas aeruginosa, a well-known cause of nosocomial infection, is frequently antibiotic resistant and this complicates treatment. Links between oxidative stress responses inducing antibiotic resistance through over-production of RND-type efflux pumps have been reported in P. aeruginosa, but this has not previously been associated with MFS-type efflux pumps. Two MFS efflux pumps encoded by mfs1 and mfs2 were selected for study because they were found to be sodium hypochlorite (NaOCl) inducible. Antibiotic susceptibility testing was used to define the importance of these MFS pumps in antibiotic resistance and proteomics was used to characterize the resistance mechanisms involved. The results revealed that mfs1 is NaOCl inducible whereas mfs2 is NaOCl, N-Ethylmaleimide and t-butyl hydroperoxide inducible. Deletion of mfs1 or mfs2 did not affect antibiotic or paraquat susceptibility. However, over-production of Mfs1 and Mfs2 reduced susceptibility to aminoglycosides, quinolones, and paraquat. Proteomics, gene expression analysis and targeted mutagenesis showed that over-production of the MexXY RND-type efflux pump in a manner dependent upon armZ, but not amgRS, is the cause of reduced antibiotic susceptibility upon over-production of Mfs1 and Mfs2. mexXY operon expression analysis in strains carrying various lengths of mfs1 and mfs2 revealed that at least three transmembrane domains are necessary for mexXY over-expression and decreased antibiotic susceptibility. Over-expression of the MFS-type efflux pump gene tetA(C) did not give the same effect. Changes in paraquat susceptibility were independent of mexXY and armZ suggesting that it is a substrate of Mfs1 and Mfs2. Altogether, this is the first evidence of cascade effects where the over-production of an MFS pump causes over-production of an RND pump, in this case MexXY via increased armZ expression.

2003-2019: explosive spread of enterobacteria producing extended-spectrum beta-lactamases in Bangui Central African Republic.

Introductionthe spread of enterobacteria producing extended-broad-spectrum beta-lactamases (ESBL) is a global public health-problem. In a study carried in 2003-2005 at the Pasteur Institute in Bangui, 450 enterobacteria were identified in clinical isolates, of which 17 were ESBL (prevalence: 3.78%). The aim of this study was to update this data.Methodsfrom May 2018 to April 2019, a total of 941 enterobacteria were isolated and identified under identical conditions of recruitment and with the same techniques used in the previous study: phenotypic identification using Api 20E strips (bioMérieux SA, Marcy-l'Etoile, France) and antimicrobial drug susceptibility using the disk diffusion method (Bio-Rad antibiotic discs, Marnes la Coquette, France). Resistance genes were identified by polymerase chain reaction (PCR) and sequencing.Resultsfrom May 2018 to April 2019, a total of 941 enterobacteria were isolated of which 478 were ESBL, thus amounting to a prevalence of 50.80%. The genetic profiles of the bla CTX-M resistance genes exhibited the emergence of the CTX-M28 variant (CTX-M1 group) and variants of the M2 and M9 groups. There was also a notable increase, from 35 to 64%, in the ESBL with a bla SHV gene.Conclusionthis study documents a 13 fold increase in the prevalence of ESBL derived from clinical isolates of the bacteriology laboratory of the Institute Pasteur in Bangui, by comparing its data with that of the publication by Frank et al. 2006. Together with this increase a significant diversification of the circulating CTX-M resistance genes was noticed.

Prevalence of asymptomatic urinary tract infection due to escherichia coli among pregnant women attending ANC clinic at BRIMS teaching hospital

Introduction: Urinary tract infection (UTI) due to Escherichia coli (E. coli) is a common health problem among women. Pregnant women are at increased risk from both symptomatic and asymptomatic UTI because of the physiologic changes associated with pregnancy which may cause complications such as pyelonephritis, chronic renal failure, premature delivery and foetal mortality. Our study aimed to check the prevalence of asymptomatic UTI due to E. coli and its antibiotic profile among pregnant women of Bidar district of North Karnataka, India. Materials and Methods: An independent study was done from January to February 2015 to investigate asymptomatic UTI among pregnant women attending Antenatal care clinic (ANC) of Bidar Institute of Medical sciences (BRIMS) Teaching hospital Bidar. 150 mid-stream urine samples were processed for culture and antimicrobial drug susceptibility testing at Department of Microbiology, BRIMS, Bidar as per the routine microbiological techniques. Diagnosis of UTI was made when there were at least 105 colony forming unit (CFU)/ml of urine. Isolates other than E. coli are not considered for this study. Results: Among 150 samples tested, 65 samples grown E. coli with colony count of 105 CFU/ml of urine. (43.33%).The Majority of pregnant women were in their 2nd and 3rd trimester and the mean age of study population was 23.46. The rate of UTI was highest among age group of 20-25 years. E. coli isolates showed highest resistance to antibiotics Ampicillin (96.92%), Cefuroxime (55.38%) and ceftriaxone (53.85%). It was uniformly sensitive to routinely used drugs for treatment of UTI. Discussion: Many Gram negative and Gram positive organisms including Yeast cause UTI in pregnant women. Our study revealed the high prevalence of asymptomatic UTI among pregnant women due to E. coli in Bidar (43.33%) as compared to studies conducted in other parts Karnataka. This study also showed the antibiotic profile of E. coli to different drugs tested and showed highe