Diarrheal Diseases: A Review on Gastroenteritis Bacteria Global Burden and Alternative Control of Multidrug-Resistant Strains

Diarrheal diseases represent a significant and pervasive health challenge for humanity. The aetiology of diarrheal diseases is typically associated with the presence of enteropathogens, including viruses, bacteria and parasites. The implementation of preventive measures, including the maintenance of good food hygiene, effective water sanitation, and the development of rotavirus vaccines, has resulted in a notable reduction in the prevalence of the disease. However, the emergence of bacterial multidrug resistance due to the past or present inappropriate use of antibiotics has rendered bacterial infections a significant challenge. The objective of this review is threefold: firstly, to provide an overview of diarrheal diseases associated with bacteria;secondly, to offer a concise analysis of bacterial multidrug resistance on a global scale;and thirdly, to present the potential of filamentous fungi as an alternative solution to the challenge posed by multidrug-resistant strains. Campylobacter spp. is the most dangerous bacteria, followed by Shigella spp. and Vibrio cholerae in all age groups combined. However, Shigella spp. was the deadliest in children under five years of age and, together with E. coli, are the most antibiotic-resistant bacteria. With their highly developed secondary metabolism, fungi are a reservoir of natural bioactive compounds.

Low-Level Antibiotic Resistance among Staphylococcus aureus and Gram-Negative Pathogens from Infected Skin and Soft Tissues in Rural Kenya

Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insights on antimicrobial susceptibilities in a rural setting, we examined specimens from suspected SSTIs from two public health facilities in Kenya. We additionally assessed antibiotic use, appropriateness of empiric therapy and risk factors for SSTI. Methodology: Between 2021 and 2023, 265 patients at Kisii and Nyamira County Referral hospitals were enrolled. Wound swabs/aspirates were collected and processed following standard microbiological procedures. Identification and antimicrobial susceptibility were performed using the VITEK 2 Compact platform. Demographic, clinical, and microbiological data were analyzed with R Statistical software. Results: S. aureus was isolated in 16.2% (43/265) of patients with a methicillin resistance (MRSA) proportion of 14% (6/43). While 13/15 drugs elicited susceptibilities ranging from 84% - 100%, penicillin (16%) and trimethoprim-sulfamethoxazole [TMP-SXT] (23%) yielded the lowest susceptibilities. Escherichia coli (n = 33), Klebsiella pneumoniae (n = 8), Pseudomonas aeruginosa (n = 8), and Citrobacter species (n = 4) were the most commonly isolated gram-negative species. Gram-negative strains showed high susceptibilities to most of the tested drugs (71% - 100%) with the exception of ampicillin (18%), TMP-SXT (33%), and first and second generation cephalosporins. Conclusions: The low MRSA prevalence and generally high antibiotic susceptibilities for S. aureus and gram-negative bacteria present opportunities for antibiotic stewardship in the study setting. Diminished susceptibilities against penicillin/ampicillin and TMP-SXT accord with prevailing local data and add a layer of evidence for their cautious empiric use.

Association between infections caused by multidrug-resistant gram-negative bacteria and mortality in critically ill patients

The incidence of gram-negative multidrug-resistant(MDR) bacterial pathogens is increasing in hospitals and particularly in the intensive care unit(ICU) setting. The clinical consequences of infections caused by MDR pathogens remain controversial. The purpose of this review is to summarize the available data concerning the impact of these infections on mortality in ICU patients. Twenty-four studies, conducted exclusively in ICU patients, were identified through Pub Med search over the years 2000-2015. Bloodstream infection was the only infection examined in eight studies, respiratory infections in four and variable infections in others. Comparative data on the appropriateness of empirical antibiotic treatment were provided by only seven studies. In ten studies the presence of antimicrobial resistance was not associated with increased mortality; on the contrary, in other studies a significant impact of antibiotic resistance on mortality was found, though, sometimes, mediated by inappropriate antimicrobial treatment. Therefore, a direct association between infections due to gram-negative MDR bacteria and mortality in ICU patients cannot be confirmed. Sample size, presence of multiple confounders and other methodological issues may influence the results. These data support the need for further studies to elucidate the real impact of infections caused by resistant bacteria in ICU patients.

Seafood as a Reservoir of Gram-negative Bacteria Carrying Integrons and Antimicrobial Resistance Genes in Japan

PCR and DNA sequencing were used to screen and characterize integrons and resistance genes in Gram-negative bacteria isolated from seafood products in Japan.A total of 215 Gram-negative bacteria were isolated from local and imported seafood samples collected from retail markets in Hiroshima Prefecture.Class 1 integrons containing gene cassettes encoding resistance to trimethoprim

Impact of Polymyxin Resistance on Virulence and Fitness among Clinically Important Gram-Negative Bacteria

Humanity is facing an enormous and growing worldwide threat from the emergence of multi-drug-resistant(MDR)Gram-negative bacteria such as Escherichia coli,Klebsiella pneumoniae,and Acinetobacter baumannii.Polymyxin B and E(colistin)constitute the last-line therapies for treating MDR Gram-negative bacteria.Polymyxin is a cationic antibacterial peptide that can destroy the outer membrane of Gram-negative bacteria.With the increasing clinical application of polymyxin,however,there have been many reports of the occurrence of polymyxin-resistant Gram-negative bacteria.This resistance is mainly mediated by the modification or complete loss of lipopolysaccharide(LPS).LPS is also a virulence factor of Gram-negative bacteria,and alterations of LPS may correlate with virulence.Although it is generally believed that the biological costs associated with drug resistance may enable benign susceptible bacteria to overcome resistant bacteria when antibiotic pressure is reduced,some studies have shown that polymyxin-resistant bacteria are associated with higher virulence and greater fitness compared with their susceptible counterparts.To predict the development of polymyxin resis-tance and evaluate interventions for its mitigation,it is important to understand the relative biological cost of polymyxin resistance compared with susceptibility.The impact of polymyxin resistance mecha-nisms on the virulence and fitness of these three Gram-negative bacteria are summarized in this review.

Ventilator-associated pneumonia in patients with cancer: Impact of multidrug resistant bacteria

BACKGROUND Patients with cancer have several risk factors for developing respiratory failure requiring mechanical ventilation(MV).The emergence of multidrug resistant bacteria(MDRB)has become a public health problem,creating a new burden on medical care in hospitals,particularly for patients admitted to the intensive care unit(ICU).AIM To describe risk factors for ventilator-acquired pneumonia(VAP)in patients with cancer and to evaluate the impact of MDRB.METHODS A retrospective study was performed from January 2016 to December 2018 at a cancer referral center in Mexico City,which included all patients who were admitted to the ICU and required MV≥48 h.They were classified as those who developed VAP versus those who did not;pathogens isolated,including MDRB.Clinical evolution at 60-d was assessed.Descriptive analysis was carried out;comparison was performed between VAP vs non-VAP and MDRB vs non-MDRB.RESULTS Two hundred sixty-three patients were included in the study;mean age was 51.9 years;52.1%were male;68.4%had solid tumors.There were 32 episodes of VAP with a rate of 12.2%;11.5 episodes/1000 ventilation-days.The most frequent bacteria isolated were the following:Klebsiella spp.[n=9,four were Extended-Spectrum Beta-Lactamase(ESBL)producers,one was Carbapenem-resistant(CR)];Escherichia coli(n=5,one was ESBL),and Pseudomonas aeruginosa(n=8,two were CR).One Methicillin-susceptible Staphylococcus aureus was identified.In multivariate analysis,the sole risk factor associated for VAP was length of ICU stay(OR=1.1;95%CI:1.03-1.17;P=0.003).Sixty-day mortality was 53%in VAP and 43%without VAP(P=0.342).There was not higher mortality in those patients with MDRB.CONCLUSION This study highlights the high percentage of Gram-negative bacteria,which allows the initiation of empiric antibiotic coverage for these pathogens.In this retrospective,single center,observational study,MDRB VAP was not directly linked to increased mortality at 60 days.

Synergistic Effect of Combined Antibiotics against Some Selected Multidrug Resistant Human Pathogenic Bacteria Isolated from Poultry Droppings in Akure, Nigeria

Antibiotic resistant bacteria pass between humans, between animals and between humans and animals in both directions, the use of antibiotics in poultry has contributed to multiple antibiotic resistant in pathogenic bacteria and use of two antibiotics might prevent the emergence of resistance to either. In this study, synergistic effect of combined antibiotics against multidrug resistant human pathogenic bacterial isolates from poultry droppings in Akure, Nigeria was examined. Collection of samples, isolation and identification of bacteria were carried out using standard microbiological method, antibiotic sensitivity test was performed by disc diffusion method and zone of inhibition was used to interpret the sensitivity test as resistant, susceptible or intermediate while combined effects of two antibiotics were investigated by macrobroth dilution and checkerboard assay methods while the synergetic effects of combined antibiotics were calculated using Fractional Inhibitory Concentration (FIC) and percentage synergistic interaction was calculated. All the ten (10) species of bacterial isolates were multidrug resistant and are less resistant to ofloxacin. The highest percentage synergistic interactions observed were Ofloxacin + Amoxicillin (90%), Ciprofloxacin + Amoxicillin (90%), Tetracycline + Amoxicillin (70%), Tetracycline + Augmentin (80%), Cotrimoxazol + Amoxicillin (50%), Cotrimoxazol + Augmentin (70%), Chloramphenicol + Amoxicillin (70%) and Chloramphenicol + Augmentin (80%). Poultry droppings is a potential source of human pathogenic bacteria, high frequency of multiple antibiotic resistance bacteria observed in this study is of great treat to man as this may cause the treatment of infection caused by these bacteria to be difficult. Combination of beta-lactam antibiotic with fluoroqunolones, tetracycline, Chloramphenicol and Cotrimoxazole was synergetic and this will reduce dose related toxicity and prevent resistance to single antibiotic.

Prevalence and Antimicrobial Resistance of Gram-Negative Bacteria Isolates in Shellfish Samples from Two River Estuaries in South-South Nigeria

Antibiotic resistant bacteria pathogens remain the leading cause of shellfish borne diseases and a major health threat to humans worldwide. The objectives of this study were to isolate, identify, and determine the antibiotic resistance patterns of Gram-negative bacteria from shellfish. We analyzed a total of 540 shellfish (117 clams, 88 oysters, and 136 periwinkles) samples collected from different vendors at Iko and Douglas Creeks in Akwa Ibom State, South-South Nigeria. Conventional cultural techniques, morphological, biochemical characteristics, and PCR amplification were used to identify the bacterial isolates. Antibiotic susceptibility tests (Kirby-Bauer disk diffusion method) and ESBL phenotype (disk) of the isolates were performed. One hundred and thirty-five (135) Gram-negative bacteria comprising 5 genera and 14 species were detected at a prevalence of: Alcaligenes faecalis TRB-7 38 (28.2%), Pseudomonas oryzihabitans strain KCB005 16 (11.9%), Paenalcaligenes retgerii strain B5 12 (8.9%) Pseudomonas aeruginosa JB2 10 (7.4%), Providencia stuartii DMC-28b 9 (6.7%), Alcaligenes species TLT151 8 (5.9%), Pseudomonas aeruginosa CIFRI DTSB1 7 (5.2%), Paenalcaligenes species UN24 7 (5.2%), Alcaligenes faecalis BT10 7 (5.2%), Vibrio species strain PrVy108 6 (4.4%), Pseudomonas xiamenensis C10-2 5 (3.7%), Providencia vemicola Bu15_38 4 (2.9%), Pseudomonas anguillisceptica 4029 3 (2.2%), and Pseudomonas aeruginosa N15-01092 3 (2.2%). All tested isolates showed various degrees of resistance to the thirteen antimicrobials evaluated. High levels of resistance (100%) to cefepime and imipenem were expressed by all isolates except the Providencia species. For the EBSL indicators, all isolates apart from Alcaligenes species were resistant (100%) to ceftriaxone. All Vibrio species were susceptible to norfloxacin, nalidixic acid, and ceftazidime. The identification of antibiotic resistant Gram-negative bacteria (GNARB) from shellfish in this study highlights the risk of disseminated multi-drug resistance—a serious public health concern.

Risk factors and mortality rates of carbapenem-resistant Gram-negative bacterial infections in intensive care units

Background The prevalence of hospital-acquired infections caused by carbapenem-resistant gram-negative bacteria(CRGNB)is increasing worldwide.Several risk factors have been associated with such infections.The present study aimed to identify risk factors and determine the mortality rates associated with CRGNB infections in intensive care units.Methods This retrospective case-control study was conducted at Erciyes University Hospital(Kayseri,Turkey)between January 2017 and December 2021.Demographic and laboratory data were obtained from the Infection Control Committee data and record system.Patients who had CRGNB infection 48–72 h after hospitalization were assigned to the case group,while those who were not infected with CRGNB during hospitalization formed the control group.Risk factors,comorbidity,demographic data,and mortality rates were compared between the two groups.Results Approximately 1449 patients(8.97%)were monitored during the active follow-up period;of those,1171 patients were included in this analysis.CRGNB infection developed in 14 patients(70.00%)who had CRGNB colonization at admission;in 162(78.26%)were colonized during hospitalization,whereas 515(54.56%)were not colonized.There was no significant difference in age,sex(male/female)or comorbidities.The total length of hospital stay was statistically significantly longer(P=0.001)in the case group(median:24[interquartile range:3–378]days)than the control group(median:16[interquartile range:3–135]days).The rates of colonization at admission(25.5%;vs.10.6%,P=0.001)and mortality(64.4%vs.45.8%,P=0.001)were also significantly higher in the cases than in the control group,respectively.In the univariate analysis,prolonged hospitalization,the time from intensive care unit admission to the development of infection,presence of CRGNB colonization at admission,transfer from other hospitals,previous antibiotic use,enteral nutrition,transfusion,hemodialysis,mechanical ventilation,tracheostomy,reintubation,central venous catheter,arterial catheterization,chest tube,total parenteral nutrition,nasogastric tube use,and bronchoscopy procedures were significantly associated with CRGNB infections(P<0.05).Multivariate analysis identified the total length of stay in the hospital(odds ratio[OR]=1.02;95%confidence interval[CI]:1.01 to 1.03;P=0.001),colonization(OR=2.19;95%CI:1.53 to 3.13;P=0.001),previous antibiotic use(OR=2.36;95%CI:1.53 to 3.62;P=0.001),intubation(OR=1.59;95%CI:1.14 to 2.20;P=0.006),tracheostomy(OR=1.42;95%CI:1.01 to 1.99;P=0.047),and central venous catheter use(OR=1.62;95%CI:1.20 to 2.19;P=0.002)as the most important risk factors for CRGNB infection.Conclusions Colonization,previous use of antibiotics,and invasive interventions were recognized as the most important risk factors for infections.Future research should focus on measures for the control of these parameters.

Antibacterial activities of ethanol extracts of Philippine medicinal plants against multidrug-resistant bacteria

Objective: To investigate the antibacterial activities of crude ethanol extracts of 12 Philippine medicinal plants.Methods: Crude ethanol extracts from 12 Philippine medicinal plants were evaluated for their antibacterial activity against methicillin-resistant Staphylococcus aureus, vancomycinresistant Enterococcus, extended spectrum β-lactamase-producing, carbapenem-resistant Enterobacteriaceae and metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter baumannii. Results: The leaf extracts of Psidium guajava, Phyllanthus niruri, Ehretia microphylla and Piper betle(P. betle) showed antibacterial activity against the Gram-positive methicillinresistant Staphylococcus aureus and vancomycin-resistant Enterococcus. P. betle showed the highest antibacterial activity for these bacteria in the disk diffusion(16-33 mm inhibition diameter), minimum inhibitory concentration(19-156 μg/m L) and minimum bactericidal concentration(312 μg/m L) assays. P. betle leaf extracts only showed remarkable antibacterial activity for all the Gram-negative multidrug-resistant bacteria(extended spectrum β-lactamaseproducing, carbapenem-resistant Enterobacteriaceae and metallo-β-lactamase-producing) in the disk diffusion(17-21 mm inhibition diameter), minimum inhibitory concentration(312-625 μg/m L) and minimum bactericidal concentration(312-625 μg/m L) assays. Conclusions: P. betle had the greatest potential value against both Gram-negative and Grampositive multidrug-resistant bacteria. Favorable antagonistic activities were also exhibited by the ethanol extracts of Psidium guajava, Phyllanthus niruri and Ehretia microphylla.

Extensively drug-resistant bacteria are an independent predictive factor of mortality in 130 patients with spontaneous bacterial peritonitis or spontaneous bacteremia

AIM: To evaluate the epidemiology and outcomes of culture-positive spontaneous bacterial peritonitis (SBP) and spontaneous bacteremia (SB) in decompensated cirrhosis.METHODS: We prospectively collected clinical, laboratory characteristics, type of administered antibiotic, susceptibility and resistance of bacteria to antibiotics in one hundred thirty cases (68.5% males) with positive ascitic fluid and/or blood cultures during the period from January 1, 2012 to May 30, 2014. All patients with SBP had polymorphonuclear cell count in ascitic fluid > 250/mm3. In patients with SB a thorough study did not reveal any other cause of bacteremia. The patients were followed-up for a 30-d period following diagnosis of the infection. The final outcome of the patients was recorded in the end of follow-up and comparison among 3 groups of patients according to the pattern of drug resistance was performed.RESULTS: Gram-positive-cocci (GPC) were found in half of the cases. The most prevalent organisms in a descending order were Escherichia coli (33), Enterococcus spp (30), Streptococcus spp (25), Klebsiella pneumonia (16), S. aureus (8), Pseudomanas aeruginosa (5), other Gram-negative-bacteria (GNB) (11) and anaerobes (2). Overall, 20.8% of isolates were multidrug-resistant (MDR) and 10% extensively drug-resistant (XDR). Health-care-associated (HCA) and/or nosocomial infections were present in 100% of MDR/XDR and in 65.5% of non-DR cases. Meropenem was the empirically prescribed antibiotic in HCA/nosocomial infections showing a drug-resistance rate of 30.7% while third generation cephalosporins of 43.8%. Meropenem was ineffective on both XDR bacteria and Enterococcus faecium (E. faecium). All but one XDR were susceptible to colistin while all GPC (including E. faecium) and the 86% of GNB to tigecycline. Overall 30-d mortality was 37.7% (69.2% for XDR and 34.2% for the rest of the patients) (log rank, P = 0.015). In multivariate analysis, factors adversely affecting outcome included XDR infection (HR = 2.263, 95%CI: 1.005-5.095, P = 0.049), creatinine (HR = 1.125, 95%CI: 1.024-1.236, P = 0.015) and INR (HR =1.553, 95%CI: 1.106-2.180, P = 0.011).CONCLUSION: XDR bacteria are an independent life-threatening factor in SBP/SB. Strategies aiming at restricting antibiotic overuse and rapid identification of the responsible bacteria could help improve survival.

Isolation and Identification of Multi-Drug Resistant Strains of Non-Lactose Fermenting Bacteria from Clinical Refuses in Major Hospitals of Khyber Pakhtunkhwa, Pakistan

Purpose: The present studied was performed in order to investigate the drug resistance of different non-lactose fermenting gram negative bacteria from clinical isolates. The bacteria were morphologically characterized through culturing and gram staining techniques were used for the identification of different bacterial strains. Methods: A total of 324 samples were collected from patients, after they were diagnosed by physicians at different hospitals at district Peshawar. Samples were morphologically identified by blood agar, MacConkey agar and Eosine Methylene Blue, identified by gram staining techniques. Modified Kirby-Bauer Disc diffusion method was used to test the in-vitro susceptibility of the identified isolates to different antibiotics. Results: The non-lactose fermenting gram negative bacteria were isolated from samples of blood (33.30%), pus/ wound (33.30%), urine (23.30%) and from ascetic/pleural fluids (10.20%). The study revealed that Pseudomonas aeroginosa showed high resistance against Gentamicin (74%) and Aztreonam (74%), followed by Ciprofloxacin (59.20%) and Amikacin (33.30). Tazocin was active as low resistance (18.50%) is shown. More resistance was seen in Morganella morganii against Aztreonam (77.7%) followed by Gentamicin (62.90%), Ciprofloxacin (40.70%). Tazocin show low resistance (3.70%). Multidrug resistant Proteus mirabillis was highly resistance to Gentamicin (66.60%), followed by Aztreonam (62.90%), Amikacin (55.50%), Ciprofloxacin (40.20%) and low resistance to Tazocin was (22.20%). Salmonella typhi demonstrated high resistance against Amikacin (62.90%), followed by Aztreonam (48.10%), Tazocin (40.70%). Gentamicin showed low resistance (29.60%), and hence it is more active against S. typhi. Conclusions: It can be concluded from the present study that different species of non-lactose fermenting gram negative bacteria have shown a different resistivity pattern. This study is a gate way for better and suitable management strategy for the infections caused by non-Lactose fermenting bacteria in the sampling region.

Five-year analysis of isolated pathogens and antibiotic resistance of ocular infections from two large tertiary comprehensive hospitals in east China

AIM:To analyze the spectrum of isolated pathogens and antibiotic resistance for ocular infections within 5y at two tertiary hospitals in east China.METHODS:Ocular specimen data were collected from January 2019 to October 2023.The pathogen spectrum and positive culture rate for different infection location,such as keratitis,endophthalmitis,and periocular infections,along with antibiotic resistance were analyzed.RESULTS:We included 2727 specimens,including 827(30.33%)positive cultures.A total of 871 strains were isolated,530(60.85%)bacterial and 341(39.15%)fungal strains were isolated.Gram-positive cocci(GPC)were the most common ocular pathogens.The most common bacterial isolates were Staphylococcus epidermidis(25.03%),Staphylococcus aureus(7.46%),Streptococcus pneumoniae(4.59%),Corynebacterium macginleyi(3.44%),and Pseudomonas aeruginosa(3.33%).The most common fungal genera were Fusarium spp.(12.74%),Aspergillus spp.(6.54%),and Scedosporium spp.(5.74%).Staphylococcus epidermidis strains showed more than 50%resistance to fluoroquinolones.Streptococcus pneumoniae and Corynebacterium macginleyi showed more than 90%resistance to erythromycin.The percentage of bacteria showing multidrug resistance(MDR)significantly decreased(χ^(2)=17.44,P=0.002).CONCLUSION:GPC are the most common ocular pathogens.Corynebacterium macginleyi,as the fourth common bacterium,may currently be the local microbiological feature of east China.Fusarium spp.is the most common fungus.More than 50%of the GPC are resistant to fluoroquinolones,penicillins,and macrolides.However,the proportion of MDR strains has been reduced over time.

Mechanisms of tigecycline resistance in Gram-negative bacteria:A narrative review

Tigecycline serves as a critical“final-resort”antibiotic for treating bacterial infections caused by multidrug-resistant bacteria for which treatment options are severely limited.The increasing prevalence of tigecycline resistance,particularly among Gram-negative bacteria,is a major concern.Various mechanisms have been iden-tified as contributors to tigecycline resistance,including upregulation of nonspecific Resistance Nodulation Divi-sion(RND)efflux pumps due to mutations in transcriptional regulators,enzymatic modification of tigecycline by monooxygenase enzymes,and mutations affecting tigecycline binding sites.This review aims to consolidate our understanding of tigecycline resistance mechanisms in Gram-negative bacteria and offer insights and perspectives for further drug development.

Immunogenomics for identification of disease resistance genes in pigs: a review focusing on Gram-negative bacilli

Over the past years, infectious disease has caused enormous economic loss in pig industry. Among the pathogens, gram negative bacteria not only cause inflammation, but also cause different diseases and make the pigs more susceptible to virus infection. Vaccination, medication and elimination of sick pigs are major strategies of controlling disease. Genetic methods, such as selection of disease resistance in the pig, have not been widely used. Recently, the completion of the porcine whole genome sequencing has provided powerful tools to identify the genome regions that harboring genes controlling disease or immunity. Immunogenornics, which combines DNA variations, transcriptorne, immune response, and QTL mapping data to illustrate the interactions between pathogen and host immune system, will be an effective genomics tool for identification of disease resistance genes in pigs. These genes will be potential targets for disease resistance in breeding programs. This paper reviewed the progress of disease resistance study in the pig focusing on Gram-negative bacilli. Major porcine Gram-negative bacilli and diseases, suggested candidate genes/pathways against porcine Gram-negative bacilli, and distributions of QTLs for immune capacity on pig chromosomes were summarized. Some tools for immunogenomics research were described. We conclude that integration of sequencing, whole genome associations, functional genomics studies, and immune response information is necessary to illustrate molecular mechanisms and key genes in disease resistance.

Isolation and Identification of Multi-Drug Resistant Strains of Non-Lactose Fermenting Bacteria from Clinical Isolates

Purpose: We studied the drug resistance of different microbes from clinical isolates. The morphological characteristics of bacteria were observed through culture characteristics and by carrying out gram staining techniques while the biochemical characteristics of bacteria were carried out by biochemical test. Methods: A total of 324 samples were collected from suspected patients visiting different hospitals at district Peshawar. For morphological identification, samples of clinical isolates were analyzed by blood agar, MacConkey agar and Eosine Methylene Blue, identified by gram staining and characterized by different biochemical tests. Antibiotic Sensitivity test by Modified Kirby-Bauer Disc diffusion method was used to test the in-vitro susceptibility of the identified isolates to different antibiotics such as Ceftazidime, Ceftazidime, Ceftriaxone, Cefepime and Imipenem. Results: These resistant non-lactose fermenting gram negative bacteria were isolated from samples of pus/wound (33.30%, n = 108/324), blood (33.30%, n = 108/324), urine (23.30%, n = 75/324) and from ascetic/pleural fluids (10.20%, n = 33/324). The study revealed that the percentage of non-fermenting bacterial infection was higher in females (53%) as compared to males (47%) along with higher infection observed in the age group of 11 - 30 years. Pseudomonas aeroginosa showed high resistance against Cefepime (88.80%), followed by Cefoperazone (55.50%), Ceftazidime (48.10%), Ceftriaxone (33.30%). Imipenem was active with low resistance (7.40%). More resistance was seen in Morganella morganii against Imipenem (66.70%) followed by Cefoperazone (55.50%), Ceftriaxone (55.50%). Cefepime showed low resistance (11%). Multi-drug resistant Proteus mirabillis was highly resistance to Ceftriaxone (74.07%), followed by Cefepime (59.20%), Cefoperazone (44.40%) and low resistance for Imipenem (25.90%). Salmonella typhi demonstrated high resistance against Imipenem (74.07%), followed by Ceftriaxone (40.70%), Ceftazidime (37.03%). Cefepime showed low resistance (3.70%), hence it is more active against S. typhi. Conclusions: The different species of non-lactose fermenting gram negative bacteria have shown a different resistivity pattern in the present study. Therefore identification of non-lactose fermenting gram negative bacteria and looking after their resistivity/susceptibility pattern are important for suitable management of the infections caused by them.

Isolation and Characterization of Multi-Drug Resistant Bacteria from Hospital Wastewater Sites around the City of Aizawl, Mizoram

A microbial study was conducted from wastewater soils of hospitals in Aizawl, Mizoram, India which were in existence for a longtime. The isolated bacteria from the wastewater soils were found to be mainly of Morganella morganii and Bacillus cereus and these isolated bacteria were found to be very resistant to a wide range of antibiotics and heavy metals. Antibiotics that were used for treating infections caused by these bacteria like chloramphenicol and ciprofloxacin were also found to be insensitive. The degree of resistance was also very high when compared to earlier reports of antibiotic resistance observed in the corresponding bacteria. Our results suggested that the high degree of resistance is probably conferred by the continued exposure to antibiotics from hospital waste leading to a selected population of highly antibiotics-resistant bacteria.

Control of multidrug-resistant planktonic Acinetobacter baumannii:biocidal efficacy study by atmospheric-pressure air plasma

In this research,an atmospheric-pressure air plasma is used to inactivate the multidrug-resistant Acinetobacter baumannii in liquid.The efficacy of the air plasma on bacterial deactivation and the cytobiological variations after the plasma treatment are investigated.According to colony forming units,nearly all the bacteria（6-log） are inactivated after 10 min of air plasma treatment.However,7% of the bacteria enter a viable but non-culturable state detected by the resazurin based assay during the same period of plasma exposure.Meanwhile,86% of the bacteria lose their membrane integrity in the light of SYTO 9/PI staining assay.The morphological changes in the cells are examined by scanning electron microscopy and bacteria with morphological changes are rare after plasma exposure in the liquid.The concentrations of the long-living RS,such as H2O2,NO3^- and O3,in liquid induced by plasma treatment are measured,and they increase with plasma treatment time.The changes of the intracellular ROS may be related to cell death,which may be attributed to oxidative stress and other damage effects induced by RS plasma generated in liquid.The rapid and effective bacteria inactivation may stem from the RS in the liquid generated by plasma and air plasmas may become a valuable therapy in the treatment of infected wounds.

Overview of Multidrug-Resistant Pseudomonas aeruginosa and Novel Therapeutic Approaches

Gram-negative bacilli Pseudomonas aeruginosa is an important pathogen in hospitalized patients, contributing to their morbidity and mortality due to its multiple resistance mechanisms. Therefore, as therapeutic options become restricted, the search for new agents is a priority. Latterly an accelerated increase in frequency of multidrug-resistant clinical strains has severely limited the availability of therapeutic options. Several in vitro and in vitro studies evaluating the efficacy of different antimicrobials agents and development of vaccines against P. aeruginosa have been reported as novel approaches, such as inhibition of virulence factor expression or inhibition of their metabolic pathways.

Aerosolized Amikacin as Adjunctive Therapy of Ventilator-associated Pneumonia Caused by Multidrug-resistant Gram-negative Bacteria： A Single-center Randomized Controlled Trial

Background： Aerosolized amikacin （AA） is a current option for the management of ventilator-associated pneumonia （VAP） caused by multidrug-resistant Gram-negative bacteria （MDR-GNB）, as it is reported that AA could increase the alveolar level of the drug without increasing systemic toxicity. This study aimed to evaluate the efficacy and safety of AA as an adjunctive therapy for VAP caused by MDR-GNB. Methods： In this single-center, double-blind study conducted in a 36-bed general Intensive Care Unit （ICU） in a tertiary hospital from June 2014 to June 2016, 52 ICU patients with confirmed MDR-GNB VAP were randomized to two groups （AA group, n - 27 and placebo group, n = 25）. Amikacin （400 rag, q8h） or saline placebo （4 ml, q8h） was aerosolized for 7 days. The attending physician determined the administration of systemic antibiotics for VAP. Patients were tbllowed up for 28 days. Bacteriological eradication, clinical pulmonary infection score （CP1S）, and serum creatinine were assessed on day 7 of therapy. New resistance to amikacin, cure rate of VAP, weaning rate, and mortality were assessed on day 28. Results： The baseline characteristics of patients in both groups were similar. At the end of the treatment, 13 of the 32 initially detected bacterial isolates were eradicated in AA group, compared to 4 of 28 in placebo group （41% vs. 14%, P - 0.024）. As for patients, 11 of 27 patients treated with AA and 4 of 25 patients treated with placebo have eradication （41% vs. 16%, P = 0.049）. The adjunction of AA reduced CPIS （4.2 ± 1.6 vs. 5.8 ± 2.1, P = 0.007）. New drug resistance to amikacin and the change in serum creatinine were not detected in AA group. No significant differences in the clinical cure rate in survivors （48% vs. 35%, P = 0.444）, weaning rate （48% vs. 32%, P = 0.236）, and mortality （22% vs. 32%, P = 0.427） were detected between the two groups on day 28. Conclusions： As an adjunctive therapy of MDR-GNB VAP, AA successfully eradicated existing MDR organisms without inducing new resistance to amikacin or change in serum creatinine. However, the improvement of mortality was not found.