A note on antibiotic resistance in the bacterial flora of raw sewage and sewage-polluted River Tigris in Mosul, Iraq

Polluted water samples collected from the River Tigris in the vicinity of a raw sewage outfall were examined for the incidence of antibiotic resistance among coli-form bacteria on three occasions during 1983. Eighty percent or more of the coli-form bacteria were resistant to one or more antibiotics. At the same time, raw sewage samples were examined for the incidence of antibiotic-resistant bacteria, and Escherchia coli, Pseudomonas spp. and Staphylococcus spp. were selected for sensitivity testing. Collectively, more than 90% of the 480 strains of the three organisms were resistant to one or more antibiotics. The minimal inhibitory concentration (MIC) of ampicillin for twenty-nine strains including coliforms, E. coli, Klebsiella sp., Serratia sp., Ps. aeruginosa, Pseudomonas sp., Micrococcus sp., Staph. aureus, Streptococcus faecalis and Bacillus sp. from raw sewage and polluted River Tigris water was determined and that for Ps. aeruginosa was 250 μg/ml. The high incidence of antibiotic-resistant bacteria in natural waters could be related to the widespread use of antibiotics in this locality.     

A note on antibiotic-resistant Escherichia coli in adult man, raw sewage and sewage-polluted River Tigris in Mosul, Nineva

A total of 600 isolates of Escherichia coli were isolated, over a 9 month period during 1984, from healthy human adults, raw sewage and the sewage-polluted River Tigris in Nineva. Over 90% of these organisms were E. coli type 1, but only 8.3% could be serogrouped as enteropathogenic E. coli . Resistance of these organisms to 11 antimicrobial drugs was assessed. Over 40% were antibiotic-resistant and of these 77.1% were resistant to more than one antibiotic. The minimal inhibitory concentration of ampicillin for 193 selected strains from the various sources was determined and ranged from <0.625- > 160 μg/ml. The high incidence of antibiotic-resistant E. coli in this locality and the possible implications to human health are discussed.     

A note on antibiotic-resistant Escherichia coli in adult man, raw sewage and sewage-polluted River Tigris in Mosul, Nineva

A total of 600 isolates of Escherichia coli were isolated, over a 9 month period during 1984, from healthy human adults, raw sewage and the sewage-polluted River Tigris in Nineva. Over 90% of these organisms were E. coli type 1, but only 8.3% could be serogrouped as enteropathogenic E. coli. Resistance of these organisms to 11 antimicrobial drugs was assessed. Over 40% were antibiotic-resistant and of these 77.1% were resistant to more than one antibiotic. The minimal inhibitory concentration of ampicillin for 193 selected strains from the various sources was determined and ranged from less than 0.625-greater than 160 micrograms/ml. The high incidence of antibiotic-resistant E. coli in this locality and the possible implications to human health are discussed.     

Antibiotic resistance among coliforms and Pseudomonas spp. from bodies of water around Port Harcourt, Nigeria

Samples from municipal waste water, the Bonny River estuary and wells in and around Port Harcourt were examined for bacteriological quality over a 9 month period. A total of 157 Pseudomonas spp., 133 Escherichia coli and 282 other coliforms were isolated and tested for the incidence of resistance to 10 antibiotics. All of the Pseudomonas spp. were resistant to at least one of the antibiotics while 96.2% were resistant to two or more. Most (83.5%) of the E. coli and other coliforms (91.8%) were resistant to at least one antibiotic. All strains were susceptible to gentamicin. Minimal inhibitory concentrations of ampicillin and tetracycline for E. coli ranged from 6.25 to 50 and 6.25 to 12.5 micrograms/ml, respectively. Minimal inhibitory concentrations of ampicillin and tetracycline were 1000 and 25 micrograms/ml for the Pseudomonas strains. The high incidence of bacterial resistance to antibiotics is discussed in relation to the widespread use of antibiotics, and possible public health implications.     

Antibiotic resistance among coliforms and Pseudomonas spp. from bodies of water around Port Harcourt, Nigeria

Samples from municipal waste water, the Bonny River estuary and wells in and around Port Harcourt were examined for bacteriological quality over a 9 month period. A total of 157 Pseudomonas spp., 133 Escherichia coli and 282 other coliforms were isolated and tested for the incidence of resistance to 10 antibiotics. All of the Pseudomonas spp. were resistant to at least one of the antibiotics while 96.2% were resistant to two or more. Most (83.5%) of the E. coli and other coliforms (91.8%) were resistant to at least one antibiotic. All strains were susceptible to gentamicin. Minimal inhibitory concentrations of ampicillin and tetracycline for E. coli ranged from 6.25 to 50 and 6.25 to 12.5 μg/ml, respectively. Minimal inhibitory concentrations of ampicillin and tetracycline were 1000 and 25 μg/ml for the Pseudomonas strains. The high incidence of bacterial resistance to antibiotics is discussed in relation to the widespread use of antibiotics, and possible public health implications.     

Multiresistant waterborne pathogens isolated from water reservoirs and cooling systems

Aims:  To determine the incidence of multiple antibiotic-resistant strains of the emergent human pathogens Legionella pneumophila , Pseudomonas aeruginosa and mesophilic Aeromonas species among those isolated from water reservoirs and industrial cooling systems.
Methods and Results:  Water from four natural water reservoirs and four industrial cooling towers was sampled for 1 year period. The total heterotrophs, mesophilic Aeromonas , Pseudomonas spp. and Legionella spp. counts were performed as recommended by standard procedures, and the sensitivity of the isolates to 27 antibiotics was tested. A total of 117 Aeromonas , 60 P. aeruginosa and 15  L. pneumophila strains were isolated and identified by means of biochemical tests and DNA probes. 46·4% of Aeromonas , and 100% of P. aeruginosa isolates presented multiple resistance. Legionella pneumophila strains were generally sensitive to the drugs used.
Conclusions:  Antibiotic-resistant pathogenic bacteria belonging to P. aeruginosa and mesophilic Aeromonas species are common in natural aquatic environments. Thus, the risk of waterborne diseases owing to domestic and industrial uses of freshwater should be re-examined from the increase of bacterial resistance point of view.
Significance and Impact of the Study:  These data confirm the emergence of bacteria resistant to antibiotics in aquatic environments.     

Bacteria of public health significance in blackcurrant juice

A total of 192 samples of blackcurrant juice were investigated for hygienic quality and drug resistance. The average aerobic bacteria in 1 ml of the blackcurrant juice was 4.8 x 10(8) and the average MPN was 8.4 x 10(2) coliform/100 ml. The percentage of the samples contaminated with coliform bacteria was 23.4. The incidence of Escherichia coli, Klebsiella, Pseudomonas aeruginosa, Staphylococcus aureus and faecal streptococci were 19.8, 9.9, 29.2, 14.0 and 18.2%, respectively. Biochemical and serological studies showed that 10.5% of total Escherichia coli were enteropathogenic E. coli. Of sixty strains tested against six antibacterial drugs, 57% were resistant to one or more of the drugs. The incidence of resistance to ampicillin, chloramphenicol, sulphonamide, streptomycin, tetracyline and gentamycin was 40.0, 25.0, 43.3, 18.3, 20.0 and 8.3%, respectively.     

Susceptibility and frequency of selected groups of bacteria isolated in 2001 from patients at the Holy Cross Cancer Center

The aim of the presented study was the analysis of microbiological data obtained from patients hospitalized in The Holly Cross Cancer Center in Kielce in 2001. The frequency of important nosocomial pathogens in selected specimens and their susceptibility to antibiotics were determined. The strains were identified by using commercial tests (bioMerieux) and their antibiotic susceptibility patterns were performed by disc diffusion technique. The most prevalent bacteria were Gram-negative rods of Enterobacteriaceae family (43%), mainly Escherichia coli. Only 2.7% strains of isolated Escherichia coli isolated from clinical specimens collected from hospitalized patients were beta-lactamase--positive (ESBL+). The second important group of microorganisms were Staphylococci, followed by Enterococcus spp., Pseudomonas aeruginosa and Candida spp. About twenty eight percent of Staphylococcus aureus isolates were resistant to methicillin.     

R factors in coliform-fecal coliform sewage flora of the prairies and Northwest Territories of Canada.

Coliform and fecal coliform populations found in the raw sewages and final sewage effluents of the prairie provinces and the Northwest Territories were examined for antibiotic resistance and the possession of R factors. It was determined that 8.91% of the total coliform and 10.80% of the fecal coliform populations carried R factors. The following numbers of combinations of R determinants were found: 39 in the Escherichia coli population, 6 in the Citrobacter population, 20 in the Enterobacter populations, 10 in the Klebsiella populations, and 11 in the Aeromonas populations. The maximum number of R determinants transferable simultaneously was seven; organisms with R factors containing determinants for chloramphenicol usually contained determinants for ampicillin. Of the coliform and fecal coliform populations, 2 to 4% were resistant to chloramphenicol in some provinces, and from 17 to 30% of the populations were resistant to three or more antibiotics. It was calculated that coliforms containing R factors in the raw sewage reached population levels of 1.5 X 10(7)/100 ml, and fecal coliforms containing R factors reached population levels of 8.6 X 10(5) ml. Final effluent discharges to the receiving environment contained R factor-containing coliform and fecal coliform populations of 3.1 X 10(4)/100 ml and 5.8 X 10(2)/100 ml, respectively. The incidence of bacteria containing R factors in sewage appears to be increasing with time, and their removal from sewage before discharge to the receiving environment is desirable. Consideration of data on bacteria with R factors should be made in future water quality deliberations and in discharge regulations.     

Incidence of Infectious Drug Resistance Among Fecal Coliforms Isolated from Raw Sewage

Raw sewage was examined for the incidence of antibiotic-resistant coliforms present among both total and fecal coliforms. In both groups, it was found that approximately 3% of the coliform bacteria were resistant to two or more antibiotics. Of these organisms, 48% were capable of transferring all or part of their antibiotic resistance to an antibiotic-sensitive, F⁻, derivative of Escherichia coli K-12. Among the R factors identified, those conferring resistance to streptomycin-tetracycline, ampicillin-streptomycin-tetracycline, and ampicillin or ampicillin-streptomycin accounted for 23, 20, and 15%, respectively, of the total R factors detected. The data indicate a significant level of infectious drug resistance among the fecal coliforms of the urban population. The data indicate further that because of the high incidence of coliform bacteria found to be doubly resistant to streptomycin and tetracyline, the inclusion of these antibiotics in selective media used for routine total or fecal coliform counts may serve to identify domestic sources of pollution.     

Association of qacE and qacEDelta1 with multiple resistance to antibiotics and antiseptics in clinical isolates of Gram-negative bacteria

Clinical isolates of Enterobacter cloacae, Citrobacter freundii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia were tested for resistance to antibiotics and to the antiseptics benzalkonium chloride and cetyltrimethylammonium bromide. Furthermore, they were examined for the presence of the resistance genes qacE and qacEDelta1. qacEDelta1 was detected by PCR in 10% of all (n=103) and in 81% of multiply antibiotic-resistant strains (n=15). qacE was found in only one of 37 P. aeruginosa strains. The minimum inhibitory concentrations of benzalkonium chloride, cetyltrimethylammonium bromide, and ethidium bromide were not significantly different for qacEDelta1/qacE-positive or -negative strains. Our data indicate that multiply antibiotic-resistant Gram-negative bacteria are not necessarily more resistant to quaternary ammonium compounds than antibiotic-sensitive strains even though qacE or qacEDelta1 is present.     

Effect of chlorination on antibiotic resistance profiles of sewage-related bacteria

A total of 1,900 lactose-fermenting bacteria were isolated from raw sewage influent and chlorinated sewage effluent from a sewage treatment plant, as well as from chlorinated and neutralized dilute sewage, before and after a 24-h regrowth period in the laboratory. Of these isolates, 84% were resistant to one or more antibiotics. Chlorination of influent resulted in an increase in the proportion of bacteria resistant to ampicillin and cephalothin, the increase being most marked after regrowth occurred following chlorination. Of the other nine antibiotics tested, chlorination resulted in an increased proportion of bacteria resistant to some, but a decrease in the proportion resistant to the remainder. Multiple resistance was found for up to nine antibiotics, especially in regrowth populations. Identification of about 5% of the isolates showed that the highest proportion of Escherichia coli fell in untreated sewage. Some rare and potentially pathogenic species were isolated from chlorinated and regrowth samples, including Yersinia enterocolitica, Yersinia pestis, Pasteurella multocida, and Hafnia alvei. Our results indicate that chlorination, while initially lowering the total number of bacteria in sewage, may substantially increase the proportions of antibiotic-resistant, potentially pathogenic organisms.     

Effect of chlorination on antibiotic resistance profiles of sewage-related bacteria.

A total of 1,900 lactose-fermenting bacteria were isolated from raw sewage influent and chlorinated sewage effluent from a sewage treatment plant, as well as from chlorinated and neutralized dilute sewage, before and after a 24-h regrowth period in the laboratory. Of these isolates, 84% were resistant to one or more antibiotics. Chlorination of influent resulted in an increase in the proportion of bacteria resistant to ampicillin and cephalothin, the increase being most marked after regrowth occurred following chlorination. Of the other nine antibiotics tested, chlorination resulted in an increased proportion of bacteria resistant to some, but a decrease in the proportion resistant to the remainder. Multiple resistance was found for up to nine antibiotics, especially in regrowth populations. Identification of about 5% of the isolates showed that the highest proportion of Escherichia coli fell in untreated sewage. Some rare and potentially pathogenic species were isolated from chlorinated and regrowth samples, including Yersinia enterocolitica, Yersinia pestis, Pasteurella multocida, and Hafnia alvei. Our results indicate that chlorination, while initially lowering the total number of bacteria in sewage, may substantially increase the proportions of antibiotic-resistant, potentially pathogenic organisms.     

Quantitative real-time PCR study of the influence of probiotic culture soluble fraction on the expression of Pseudomonas aeruginosa quorum sensing genes

The opportunistic pathogen Pseudomonas (Ps.) aeruginosa causes severe infections, particularly in immunocompromised individuals and patients with cystic fibrosis (CF). A serious side effect of antibiotic therapy in Ps. aeruginosa infections is the development of resistance to antibiotics. During the infection process Ps. aeruginosa forms biofilms, rendering bacterial cells more resistant to disinfectants, antibiotics and the action of host immune defense effectors. Pseudomonas aeruginosa employs the intercellular communication system, known as quorum sensing (QS) to coordinate the expression of tissue-damaging factors. Since the QS systems controls the production of different virulence factors, it is possible that the inhibition of its regulatory activity to severely compromise the ability of Ps. aeruginosa to cause infections in humans. Many studies have shown that some probiotic strains exhibit inhibitory activity on different virulence properties of pathogenic bacteria (adherence to cellular or inert substrate, soluble virulence factors expression). The aim of the present study was to investigate by real-time RT-qPCR the influence of probiotic culture soluble factors on the QS genes expression in 30 Ps. aeruginosa strains isolated from patients hospitalized in the National Institute for Cardiovascular Infections, Prof. C.C. Iliescu Fundeni Hospital, Bucharest. The results of the real time RT-qPCR have shown that in all Ps. aeruginosa strains grown in the presence of probiotic culture sterile filtrates, the level of QS genes expression was reduced comparatively with those from control cultures. In conclusion, these results proved that the inhibition of virulence factors regulation mechanisms by soluble molecules secreted by probiotics could represent an interesting way pathogenicity and virulence attenuation in Ps. aeruginosa nosocomial strains.     

The role of mechanically purified city sewers in the spread of antibiotic-resistant bacteria of the Enterobacteriaceae family

The aim of this study was to evaluate a degree of contribution of mechanically cleansed municipal sewage in a spread in on environment of bacteria of Enterobacteriaceae family with special regard to antibiotic resistant strains. High number of bacteria of Enterobacteriaceae family was found in 1 ml of sewage and the number of antibiotic-resistant bacteria was 0.5-50 X 10(3)/ml. Among the strains tested the resistance to more than one antibiotics was encountered. 78.3% of strains transferred antibiotic resistance to E. coli recipient strain, what indicate a participation of potentially pathogenic bacteria from Enterobacteriaceae family in a spread of antibiotic resistance in a environment.     

Fecal coliforms of wastewater treatment plants: antibiotic resistance, survival on surfaces and inhibition by sodium chloride and ascorbic acid.

Three hundred and sixteen fecal coliform strains isolated from raw sewage and final effluents of two representative wastewater treatment plants were examined for antibiotic resistance. For plant A (which was disinfecting its effluents before discharge), 55% and 41% of the strains isolated from the influent and the effluent, respectively were resistant to one or more antibiotics. For plant B (which was not disinfecting its effluents before discharge), 33% and 58% of the strains isolated from the influent and the effluent, respectively were resistant to one or more antibiotics. A considerable proportion of these bacteria were resistant to three or more antibiotics. NaCl (3%) and ascorbic acid (0.1%) reduced the growth rate of both sensitive and resistant strains, and more inhibitory effects on the sensitive strains than on the resistant strains were observed. All resistant strains tested survived on various types of surfaces (e.g. glass, stainless steel, agar, cabbage, parsley and sand) significantly better than sensitive strains.     

Tinopal AN as a selective agent for the differentiation of phytopathogenic and saprophytic Pseudomonas species

The selective toxicity of the respiratory inhibitor Tinopal AN (1,1-bis (3, N -5–dimethylbenzoxazol-2-yl) methine p -toluene sulphonate) towards phytopathogenic bacteria was investigated further and in general was confirmed using more than 160 additional strains of Pseudomonas spp. The mechanism(s) of the resistance shown by saprophytic fluorescent pseudomonads were studied to elucidate the differences between resistant saprophytic and sensitive phytopathogenic Pseudomonas species. Damage to, or partial removal of the cell wall of Tinopal AN-resistant Pseudomonas aeruginosa , resulted in a marked Tinopal AN-sensitivity, as judged by the ability of Tinopal AN to inhibit oxygen uptake. Furthermore, removal of part of the lipo-polysaccharide (LPS) component of the outer membrane also resulted in sensitivity. Mutants of Ps. aeruginosa with modified outer cell walls were tested for their reactions towards Tinopal AN, and two cell wall lipopolysaccharide (LPS) mutants of Escherichia coli (env Al) and Salmonella typhimurium (rfa) were, in contrast to the wild-type strains, found to be sensitive towards Tinopal AN. The results therefore suggest that the resistance of saprophytic pseudomonads towards Tinopal AN is due (at least in part) to the selectively permeable properties of the outer membrane of the cell wall. The usefulness of Tinopal AN for screening potentially phytopathogenic strains of Pseudomonas was confirmed.     

Comparative survival of antibiotic-resistant and -sensitive fecal indicator bacteria in estuarine water.

The survival of antibiotic-resistant and -sensitive strains of Escherichia coli, Enterococcus faecalis, Enterococcus faecium, Streptococcus equinus, and two environmental isolates, AP17 and AQ62, was examined in estuarine water. Each strain was rendered resistant to a combination of two antibiotics by serial passage in increasing concentrations of antibiotics. Cultures were incubated in filter-sterilized estuarine water for up to 7 days. Recovery was assessed by examining colony-forming ability on media with and without antibiotics. None of the antibiotic-resistant forms survived longer than its antibiotic-sensitive counterpart in estuarine water. Three of the resistant strains died off more rapidly than the antibiotic-sensitive wild type. Survival of the test bacteria in estuarine water was as follows: sensitive and resistant AQ62, resistant Escherichia coli less than sensitive Escherichia coli less than resistant AP17 less than resistant Enterococcus faecium less than sensitive AP17, sensitive and resistant S. equinus less than sensitive and resistant Enterococcus faecalis, sensitive Enterococcus faecium. The results supported the suggestion that fecal entercocci may serve as better indicators of fecal pollution than Escherichia coli in marine ecosystems. Moreover, the results indicated that the use of antibiotic-resistant mutants to follow the fate of bacteria in the environment is inappropriate without adequate studies to ensure that resistant and wild-type strains react similarly to environmental stressors.     

泌尿外科住院患者泌尿系感染病原菌分布及其耐药性分析

了解泌尿外科住院患者泌尿系感染病原菌的分布及其对常用抗菌药物的耐药情况。对泌尿外科泌尿系感染住院患者的消毒中段尿培养结果进行回顾性分析,尿培养菌株的鉴定、药敏分析和统计分析采用VITEK2全自动微生物仪。3 a中泌尿外科泌尿系感染住院患者共分离到细菌1 233株,其中革兰阴性杆菌772株,占62.61%,革兰阳性球菌353株,占28.63%,真菌82株,占6.65%。菌株数居前5位的细菌依次为:大肠埃希菌、肠球菌属、洋葱伯克霍尔德菌、假丝酵母菌属和变形杆菌。分离大肠埃希菌产ESBLs率为66.18%,粪肠球菌中未发现VRE菌株,屎肠球菌VRE为0.8%。未发现对美洛培南耐药的大肠埃希菌,对肠埃希菌耐药率在10%以下的有亚胺培南、阿米卡星、哌拉西林/他唑巴坦和呋喃妥因。洋葱伯克霍尔德菌和铜绿假单胞菌对所监测的抗菌药物均有不同程度的耐药。未发现对万古霉素、替考拉宁及氨苄西林耐药的粪肠球菌。泌尿系感染的病原菌以大肠埃希菌和肠球菌为主,非发酵革兰阴性杆菌及假丝酵母菌所占比例超过20%,不容忽视,病原菌的耐药率较高,临床医生应根据尿培养和药敏试验结果合理使用抗菌药物。     

Pathogens and drug-resistance of hospital-acquired pneumonia in an EICU in Tianjin,China

Objective: Observing the pathogens and drug-resistance within hospital-acquired pneumonia (HAP) in an emergency intensive care unit (EICU) to provide a reference for clinically reasonable use of antibiotics. Methods: Sixty-two patients with HAP in Tianjin Medical University General Hospital from January 2017 to May 2019 were analyzed retrospectively. Bacterial identification and susceptibility were reviewed. Results: One hundred and thirty-seven strains of pathogenic bacteria were isolated from 62 patients, with 97.1% Gram-negative and only 2.9% Gram-positive. There were also six fungal isolates. The most common pathogens were Acinetobacter baumannii, accounting for 30.8% of all isolates, followed by Klebisella spp, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Escherichia coli. Acinetobacter baumannii was poorly susceptible to piperacillin-tazobactam, cefepime, Amoxicillin+clavulonic acid, ciprofloxacin. However, the isolates were sensitive to Tigecycline, so as the isolates of Klebisella spp. Pseudomonas aeruginosa was mostly sensitive to Amikacin, followed by Tobramycin. All of the isolates of Staphylococcus aureus were susceptible to Linezolid, Tigecycline and Vancomycin. Conclusions: Gram-negative bacteria especially Acinetobacter baumannii, are the main pathogens for HAP in the observed EICU. The variety of pathogens should be monitored at regular intervals to improve resistance issues and therapeutic effect.