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PubMed1979

Bacteriological criteria for feeding raw breast-milk to babies on neonatal units.

Aerobic cultures of 207 samples of drip breast-milk from seventy mothers in hospital showed that 6 (3%) were sterile and 170 (82%) contained only the commensal organisms coagulase-negative staphylococci and Streptococcus viridans. 25 (15%) grew potential pathogens--Staphylococcus aureus in 13 (6%); enterobacteria in 15 (7%); and group-B streptococci in 3 (2%). It is proposed that milk with commensals in any numbers may be considered for use unheated but not milk containing any potential pathogens.

Aerobiosis↗

PubMed1982

The last epidemic: selective decontamination in the control of mortality among radiation victims.

Observations made in Hiroshima and Nagasaki have learned that at some distance from the hypocenter of an A-bomb explosion, individuals--in densely populated areas many thousands--may receive a radiation dose which could be survived practically all exposed persons provided bacterial infections by potentially pathogenic microorganisms could effectively be prevented. As a result deteriorating hygienic circumstances may soon promote the occurrence of epidemics by pathogenic bacteria in a zone surrounding the bombed area. This may be promoted by the presence of persons with a suppressed defence capacity due to (low dose) irradiation obtained during the explosion or later on by fall out. Both infections by potentially pathogenic microbes--most of endogenous origin--as well as infections by a number of different pathogenic bacterial species could effectively be prevented by selective decontamination (SD). SD is a method of infection prophylaxis in use in neutropenic patients such as patients with acute leukaemia during remission induction therapy. SD is performed by oral treatment with colonization resistance saving antimicrobial drugs and should start within two or three days after a nuclear explosion. Suggestions are made for the organisation of large scale treatment of many thousands of persons with SD-pills while implications of the latter for the control of epidemic spread of infections among persons living in the first aid zone who have not been exposed to radiation during or after the explosion, are also mentioned.

Decontamination↗

PubMed2026

First characterization of Staphylococcus felis in diabetic foot osteomyelitis: from intracellular persistence to phage treatment.

Staphylococcus felis is a coagulase-negative Staphylococcus (CoNS) primarily associated with the feline microbiota and only rarely reported in human disease. Here, we report its implication in diabetic foot osteomyelitis, and provide the first comprehensive characterization of its pathogenic potential. Two isolates (NSF001 and NSF002), recovered 5 months apart from bone biopsies of the same patient, were analyzed for growth kinetics, biofilm formation, and intracellular persistence in macrophages and osteoblasts. Both isolates proliferated efficiently, produced robust biofilm, and persisted within host cells, most markedly in osteoblasts. In a zebrafish embryo infection model, both isolates caused significant mortality, confirming their pathogenic potential in vivo. Whole-genome sequencing revealed conserved virulence determinants, a narrow resistome, and strain-specific genomic variations affecting genes involved in virulence regulation, phage defense, and iron acquisition. The lytic phage SAVM02, previously characterized for activity against other Staphylococcus species, effectively inhibited S. felis growth in vitro and conferred protection in vivo against lethal infection. Notably, the two sequential isolates differed in their in vivo virulence and phage susceptibility, paralleling these within-host microevolutionary changes and illustrating bacterial adaptation during chronic infection. Altogether, this study establishes S. felis as a CoNS capable of intracellular persistence, biofilm formation, and in vivo virulence in chronic human infection. Our findings also highlight the therapeutic potential of lytic phages against virulent CoNS species and support further investigation of phage therapy for chronic staphylococcal infections.IMPORTANCECoagulase-negative staphylococci (CoNS) are increasingly recognized as genuine agents of chronic infection, yet the pathogenic capacity of most individual species remains undefined. Staphylococcus felis, a commensal of cats only exceptionally reported in humans, had never been implicated in a chronic human infection. Here, we describe two sequential S. felis isolates recovered from bone biopsies of a patient with diabetic foot osteomyelitis and show that this species combines biofilm formation, intracellular persistence in macrophages and osteoblasts, and lethality in a zebrafish embryo model. Whole-genome comparison of the two isolates uncovered microevolutionary changes, most notably in iron-acquisition and genome-defense loci, that paralleled differences in virulence and phage susceptibility. These findings extend the list of CoNS capable of causing invasive human disease and provide a rationale for lytic phage therapy against emerging, difficult-to-treat staphylococcal pathogens.

Staphylococcus felis↗

PubMed1989

[A clinical study of selective gut decolonization in 204 long-term ventilated intensive care patients undergoing abdominal and accident surgery].

In a randomized clinical trial the effects of selective digestive decolonization (SDD) on the frequency of pneumonia and sepsis and the rate of lethality as well as the resistance quota and colonization of bacteria were studied in 102 surgical ICU-patients requiring prolonged mechanical ventilation. These patients received non-resorbable antibiotics: 4 x 100 mg of polymyxin B, 4 x 500 mg of amphotericin B, and 4 x 80 mg of tobramycin via gastric tube. One hundred and two patients served as controls. Patients with an expected period of mechanical ventilation of more than 4 days were included into the study. In both groups there were no significant differences regarding the degree of severity of the primary disease. The rate of pneumonia in the SDD-group was significantly lower after the third day compared with the frequency in the control group. The rate of sepsis was significantly lower after the thirteenth day, and the survival rate in the SDD-group was significantly higher after the twenty-fourth day of artificial ventilation compared with the control group. A significant reduction of the incidence of potential pathogenic gram-negative aerobe germs detected bronchially and rectally could be demonstrated within the first week in patients of the SDD-group. A secondary colonization of the oropharynx in patients of the SDD-group could not be observed. 38.8% of the patients in the control group showed potentially pathogenic microorganisms in oropharyngeal swabs. A development of resistance of pseudomonas aeruginosa against tobramycin occurred in 2.3% of the patients in the SDD-group and in 3.1% of the patients in the control group. It can be concluded that the administration of non-resorbable antimicrobials against gram-negative aerobes is an effective method for prevention of potentially fatal pneumonia and sepsis, and for the first time a significant improvement of the survival rate could be demonstrated.

Abdomen↗

PubMed2002

Bartonella henselae and Bartonella elizabethae as potential canine pathogens.

Bartonella henselae or Bartonella elizabethae DNA from EDTA-anticoagulated blood samples obtained from four dogs was amplified and sequenced. The results showed that B. elizabethae should be added to the list of Bartonella species (i.e., B. vinsonii subsp. berkhoffii, B. henselae, and B. clarridgeiae) that are currently recognized as infectious agents in dogs. Furthermore, these results may have potential zoonotic implications, particularly if dogs can serve as a previously unrecognized reservoir for B. henselae. Although the clinical relevance of these observations remains to be determined, it is possible that molecular diagnostic techniques such as PCR may help to implicate a spectrum of Bartonella spp. as a cause of or a cofactor in chronic canine and human diseases of poorly defined causation.

Animals↗

PubMed1984

An investigation of the role of true hypha production in the pathogenesis of experimental oral candidosis.

From 427 cases of human oral candidosis 2135 yeast clones were screened for the presence of germ tube-negative C. albicans and variants that formed only pseudohyphae in serum; one strain of each was found. The pathogenic potential of the serum-pseudohyphal and germ tube-negative C. albicans variants was investigated in the oral cavity of the rat; both variants failed to induce palatal candidosis, in contrast to a germ tube-positive C. albicans control strain. The pathogenic potential of C. albicans strains appears to be dependent on the formation of true germ tubes.

Animals↗

PubMed1984

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.

Anti-Bacterial Agents↗

PubMed1971

Microbiological evaluation of protected environments during patient occupancy.

Microbiological monitoring has been conducted in two life island (LI) units and two laminar airflow (LAF) rooms while they were occupied by patients undergoing cancer chemotherapy. There were only 5 organisms per 1,000 ft(3) of air sampled in LAF rooms, 31 organisms in LI units, and over 3,000 organisms in regular hospital rooms. None of the floor samples obtained from hospital rooms was sterile, compared to over 70% in LAF rooms. The rate of deposition of organisms onto settling plates was one organism per 4.5 hr in LAF rooms compared to one organism per 0.08 hr in hospital rooms. Potential pathogens were isolated much more frequently from environmental samples obtained from hospital rooms than from LI units or LAF rooms. Two sites of persistent contamination arose in the LAF rooms: the vinyl tile flooring and the water supply system. Over half of the potential pathogens cultured from the protected environment units were cultured initially from the patients who occupied the units.

Air Conditioning↗

PubMed1999

Pharyngeal flora in patients undergoing head and neck oncologic surgery.

In order to specify the correlation between pharyngeal flora and the onset of surgical wound infection, we conducted two prospective studies on patients undergoing oncologic surgical procedures with expected contamination by pharyngeal secretions. In the first study, an oropharyngeal swab and a specific swab of the tumour were collected the day before, or on the day of surgery. As potential pathogens were always isolated in the oropharyngeal swab, it was considered that the tumour is not infected but is colonised by the oropharyngeal flora. A second pharyngeal swab was collected at day 5-7 in the second study. Preliminary results in the second study showed that 50% (11/22) of patients were orpharyngeal carriers of pathogens before surgery. This rate is 70% (15/22) in the post-operative period with a higher rate of gram negative rods. WSI occurred in 7/22 patients (32%), mainly with isolated rods similar to those observed in the oropharyngeal post-operative flora and potential pathogens in 5/7 patients. More patients are necessary to establish a link between pre-operative ropharyngeal pathogens and the occurrence of SWI.

Amoxicillin-Potassium Clavulanate Combination↗

PubMed2006

Frequency of recovery of pathogens causing acute maxillary sinusitis in adults before and after introduction of vaccination of children with the 7-valent pneumococcal vaccine.

The objective of the study was to compare the proportions of the recovery of pathogens of acute maxillary sinusitis in adults in the 4-year period prior to the 5-year period that followed the introduction of vaccination of children with the 7-valent pneumococcal vaccine (PCV7). Cultures were obtained through endoscopy from 385 adults with acute maxillary sinusitis, 156 between 1997 and 2000, and 229 between 2001 and 2005. One hundred and seventeen potentially pathogenic organisms were isolated from the cultures obtained between 1997 and 2000. The predominant organisms were Streptococcus pneumoniae (54 or 46 % of all isolates), Haemophilus influenzae non-type b (42 or 36 %), Moraxella catarrhalis (7 or 6 %), Streptococcus pyogenes (8 or 7 %) and Staphylococcus aureus (6 or 5 %). One hundred and sixty-seven potentially pathogenic organisms were isolated from the cultures obtained between 2001 and 2005. The most predominant organisms were H. influenzae non-type b (71 or 43 % of all isolates), Strep. pneumoniae (58 or 35 %), M. catarrhalis (13 or 8 %), Strep. pyogenes (12 or 7 %) and Staph. aureus (13 or 8 %). Significant statistical differences were noted in the rates of recovery of H. influenzae non-type b (P < 0.05) and Strep. pneumoniae (P < 0.05). A decrease occurred in the recovery of Strep. pneumoniae resistant to penicillin from 41 to 29 %, and an increase was noted in the isolation of beta-lactamase-producing H. influenzae from 33 to 39 %; however, neither change was statistically significant. These data illustrate that a significant shift occurred in the causative pathogens of acute maxillary sinusitis in adults in the 5 years after the introduction of vaccination of children with the PCV7 compared to the previous 4 years.

Adult↗

PubMed2005

New antimycobacterial S-alkylisothiosemicarbazones.

In connection with a systematic study of antimycobacterial agents against potentially pathogenic strains the series of 12 S-alkylisothiosemicarbazones was evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, M. kansasii, M. fortuitum, two strains of M. intracellulare and three strains of M. avium. Quinoline-4-carbaldehyde-S-hexyl-isothiohydrazone was found to be more active against potentially pathogenic strains than isoniazide.

Aldehydes↗

PubMed1980

Laboratory contamination of dental prostheses.

Potential pathogenic microbiologic cross-contamination from various sources by way of the dental laboratory has been documented, and guidelines to reduce it have been published. Ten sterile, complete dentures were fractured and sent to different dental laboratories for repair. Upon return, nine were found to be contaminated with potentially pathogenic microorganisms, possibly from other patients. Dentists must ensure that the possibility of infection to patients from prosthodontic treatment does not exist.

Bacteria↗

PubMed2005

Influence of dietary zinc oxide and copper sulfate on the gastrointestinal ecosystem in newly weaned piglets.

Dietary doses of 2,500 ppm ZnO-Zn reduced bacterial activity (ATP accumulation) in digesta from the gastrointestinal tracts of newly weaned piglets compared to that in animals receiving 100 ppm ZnO-Zn. The amounts of lactic acid bacteria (MRS counts) and lactobacilli (Rogosa counts) were reduced, whereas coliforms (MacConkey counts) and enterococci (Slanetz counts, red colonies) were more numerous in animals receiving the high ZnO dose. Based on 16S rRNA gene sequencing, the colonies on MRS were dominated by three phylotypes, tentatively identified as Lactobacillus amylovorus (OTU171), Lactobacillus reuteri (OTU173), and Streptococcus alactolyticus (OTU180). The colonies on Rogosa plates were dominated by the two Lactobacillus phylotypes only. Terminal restriction fragment length polymorphism analysis supported the observations of three phylotypes of lactic acid bacteria dominating in piglets receiving the low ZnO dose and of coliforms and enterococci dominating in piglets receiving the high ZnO dose. Dietary doses of 175 ppm CuSO(4)-Cu also reduced MRS and Rogosa counts of stomach contents, but for these animals, the numbers of coliforms were reduced in the cecum and the colon. The influence of ZnO on the gastrointestinal microbiota resembles the working mechanism suggested for some growth-promoting antibiotics, namely, the suppression of gram-positive commensals rather than potentially pathogenic gram-negative organisms. Reduced fermentation of digestible nutrients in the proximal part of the gastrointestinal tract may render more energy available for the host animal and contribute to the growth-promoting effect of high dietary ZnO doses. Dietary CuSO(4) inhibited the coliforms and thus potential pathogens as well, but overall the observed effect of CuSO(4) was limited compared to that of ZnO.

Animals↗

PubMed1996

Biological significance of human endogenous retroviral sequences.

Endogenous retroviruses (ERVs) have been known for many years to exist in numerous natural and laboratory animal species. In humans it has been demonstrated that at least 1% of the genome consists of retrovirus-related sequences. Involvement of ERVs in the development of neoplastic and autoimmune diseases in the mouse model implicated a potentially pathogenic role of ERVs for humans, too. The research in this field led to a number of results strongly suggesting that human endogenous retroviral sequences (HERVs) are biologically active, on the RNA and even on the protein level. Particle formation, regulation or dysregulation of cellular gene expression, and synthesis of potentially pathogenic viral proteins indicate the broad spectrum of mechanisms by which HERVs may obtain biological significance.

Animals↗

PubMed1978

Evaluation of some methods for the laboratory examination of sputum.

Methods for the quantitation of leucocytes, squamous epithelial cells, and potential pathogens in sputa are described. Microscopic examination showed that 58% of sputa tested (554/957) were purulent or moderately purulent and 48% were moderately or heavily contaminated by squamous epithelial cells. The presence of squamous epithelial cells indicated oropharyngeal contamination. A simple dilution technique was chosen to compare the isolation of potential pathogens from direct cultures and from dilutions of sputa (10(-7) per ml original sputum). The dilution technique permitted easier reading of sputum cultures and avoided the possible over-reporting of enterobacteria and Pseudomonas aeruginosa, which were frequently found on direct examination. Enterobacteria and Pseudomonas aeruginosa were more likely to be isolated from sputa moderately or heavily contaminated with squamous epithelial cells. The use of counter-current immunoelectrophoresis (CIE) and co-agglutination tests to detect pneumococcal antigen in sputa is described. The presence of antigen in sputum was a more reliable index of lower respiratory tract infection than a positive culture. Co-agglutination tests were simpler to perform and used smaller amounts of expensive antiserum than CIE.

Antigens, Bacterial↗

PubMed2000

Bifidobacteria and lactobacilli in human health.

The gastrointestinal microflora is a complex ecological system, normally characterized by a flexible equilibrium. The most important role of the microflora, from the point of view of the host, is probably to act in colonization resistance against exogenous, potentially pathogenic, microorganisms. Bifidobacteria and lactobacilli are Gram-positive lactic acid-producing bacteria constituting a major part of the intestinal microflora in humans and other mammals. Administration of antimicrobial agents may cause disturbances in the ecological balance of the gastrointestinal microflora with several unwanted effects such as colonization by potential pathogens. To maintain or reestablish the balance in the flora, supplements of intestinal microorganisms, mainly bifidobacteria and lactobacilli, sometimes called probiotics, have been successfully used. This article reviews the role of bifidobacteria and lactobacilli in human health.

Animals↗

PubMed2003

Microbiological evaluation of various parameters in ophthalmic operating rooms. The need to establish guidelines.

PURPOSE: Postoperative infections can be caused by a contaminated environment, unsterile equipment, contaminated surfaces, and infected personnel as well as contaminated disinfectants. In order to establish guidelines for microbiological monitoring, a detailed microbiological surveillance was carried out in an ophthalmic hospital. METHOD: Over a period of 21 months, we assessed environmental Bacteria Carrying Particle(BCP) load and surface samples weekly (n = 276); the autoclaving system once a month and repeated whenever the process failed (n = 24); the air conditioning filters for fungal growth once in four months (n = 15), and the disinfectant solution for contamination once in two months (n = 10). Additionally, the personnel involved directly in surgery were screened for potential pathogens such as Staphylococcus aureus and beta haemolytic streptococci. RESULT: On 14 (5.07%) occasions the environment in the operating rooms had a significant risk of airborne infections. Sterilisation of instruments in the autoclaves was unsatisfactory on 4 (16.66%) occasions. Samples from the filters of the air-conditioning units yielded potentially pathogenic fungi on 3 (20%) occasions. Personnel sampling revealed that 5 (8.77%) individuals harboured beta haemolytic Streptococci in the throat and 4 (7.01%) harboured S. aureus in the nasal cavity. The samples of disinfectant in use were not contaminated. CONCLUSION: There is a need to standardise microbiological evaluation protocols for operating rooms.

Disinfection↗

PubMed1985

Infections in immunocompromised patients. II. Established therapy and its limitations.

Diseases affecting host defense mechanisms include neutropenia, aplastic anemia, leukemia, lymphocytopenia (B- and T-lymphocyte abnormalities), deficiencies of complement, splenectomy, diabetes mellitus, renal failure, and autoimmune diseases. Immunocompromised patients face frequent life-threatening complications of infections, particularly when they are hospitalized and receiving cytotoxic myelosuppressive drugs. Oral antimicrobial agents affect the flora of the host's alimentary tract, enhancing colonization by resistant, potentially pathogenic, strains and species, especially in a hospital environment. Nalidixic acid, oxolinic acid, pipemidic acid, polymyxins, co-trimoxazole, polyene antibiotics, and framycetin, which preserve anaerobic colon flora, do not affect the host's colonization resistance and can be given in oral doses high enough to suppress and clear susceptible potential pathogens from the intestinal tract. Such prophylactic treatment permits patients to stay hospitalized in ward conditions. In the compromised host who has fever and suspected septicemia, a decision concerning treatment should be made within an hour of notification of the patient's condition. In acute stages of life-threatening infection, the principal aim of antimicrobial chemotherapy is to provide the most potent treatment; at this stage, the accompanying side effects are less important. An essential component of therapy should be an aminoglycoside paired with a beta-lactam antibiotic. Because the incidence of staphylococcal resistance to antibiotics is high, preliminary sensitivity-testing is essential when staphylococcal sepsis threatens the life of a compromised host. Despite aggressive antibiotic therapy, more than half of immunocompromised patients and patients with severe underlying diseases die when gram-negative bacteria invade their blood. In these patients, medical or surgical removal of the septic focus is a major part of management, but plasma or plasma fractions should be given to correct hypovolemia, and an agent such as dopamine should be administered if volume replacement fails to restore adequate blood pressure. A high dose of corticosteroids should have a beneficial effect, and, for neutropenic patients with gram-negative bacteremia or fever, transfusion with functional neutrophils improves survival.

Aminoglycosides↗